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THE

VOYAGE OF H.M.S. CHALLENGER.

ZOOLOGY-VOL XXM.

in'7

REPORT

ON THE

SCIENTIFIC RESULTS

OF THE

VOYAGE OF H.M.S. CHALLENGER

DURING THE YEARS i87 3-7 6

UNDER THE COMMAND OF

Captain GEORGE S. NARES, R.N., F.R.S.

AND THE LATE

Captain FRANK TOURLE THOMSON, R.N.

PREPARED UNDER THE SUPERINTENDENCE OF

THE LATE

Sir C. WYVILLE THOMSON, Knt, F.R.S., &c.

REGIUS PROFESSOR OF NATURAL HISTORY IN THE UNIVERSITY OF EnlNBURfiH
DIRECTOR OF THE CIVILIAN SCIENTIFIC STAFF ON BOARD

AND NOW OF

JOHN MURRAY

ONE OF THE NATURALISTS OF THE EXPEDITION

Zoology— Vol. XXII.

r

Publtsl)eti bp <0iDer of l^er Jflajestp's (Sobernmeut

PRINTED FOR HER MAJESTY'S STATIONERY OFFICE

AND SOLD V.Y

LONDON :— EYRE & SPOTTISWOODE, EAST HARDING STREET, FETTER LANE

EDINBURGH ;— ADAM & CHARLES BLACK

DUBLIN :— HODGES, FIGGIS, & CO.

1887 -^2

Price Fifty Shillings. ^

APR 2 2 ^987

PRINTED BY NEILL AND COMPANY, EDINBURGH,
FOR HER majesty's STATIONERY OFFICE.

CONTENTS.

Report on. the Deep-Sea Fishes collected by H.M.S. Challenger during the years

1873-1876.

By Albert Gunther, M.A., M.D., Ph.D., F.R.S., Keeper of the

• • *

Department of Zoology in the British Museum.

EDITOEIAL NOTE.

The Report on the Deep-Sea Fishes, by Dr. Albert Giinther, F.R.S., occupies
the whole of the present Volume. This Report, which forms Part LVII. of
the Zoological Series of Reports on the Scientific Results of the Expedition,
extends to nearly 400 pages, with 73 Lithographic Plates and several
woodcuts.

The Report comprises two Appendices, the first by Professor H. N.
Moseley, F.R.S., on the structure of the Peculiar Organs on the Head of
Ipnops, the second by R. von Lendenfeld, Ph.D., on the structure of the
Phosphorescent Organs op Fishes.

With reference to the depths at which the specimens of Deep-Sea
fish were captured I desire to repeat here a statement so frequently made
in connection with these publications. During the cruise the naturalists
recorded in each case, as faithfully as possible, the depth to which the dredge
or trawl was sent down. The animals may have been captured at the
bottom, or in any of the intermediate layers between surface and bottom ; in
many cases the structure, colour, or modifications of organs, and the contents
of the stomach, furnish clear indications as to whether the animal lived
at the bottom or on the surface, and on such matters the specialists in each
group are the best judges. In this Report, therefore, the depths given for
the specimens show that Dr. Giinther regards the specimens, with a few
exceptions which are mentioned in the body of his Report, as having been
captured at the recorded depth.

This exceedingly valuable and comprehensive Report does not refer to

viii THE VOYAGE OF H.M.S. CHALLENGER.

the immature and larval specimens or pelagic fish captured at the surface of
the sea during the Expedition. It is hoped that Dr. Giinther may prepare a
short Report on these forms during the coming year.

The Manuscript was received by me in instalments between the 9th
September 1886 and the 28th June 1887.

John Murray.

Challenger Office, 32 Queen Street,
Edinburgh, \t;t Aw/ust 1887.

THE

VOYAGE OF H.M.S. CHALLENGER.

ZOOLOGY.

REPORT on the Deep-Sea Fishes collected by H.M.S. Challenger daring the
Years 1873-76. By Dr. Albert Gunthek, M.A., M.D., Ph.D., F.R.S.,
Keeper of the Department of Zoology in the British Museum.

PEEFACE.

Although the collection of Deep-Sea Fishes which was made by the naturalists of
H.M.S. Challenger was entrusted to me for investigation nearly ten years ago, the
preparation of this Eeport was delayed by the pressure of other engagements, especially
an increase of official duties. Only during the last two years I was able to steadily
apply myseK in my leisure hours to the work of re-examining the specimens and of
preparing the present Report for press.

This delay appeared to be the less a matter of regret as it was known that deep-sea
explorations were being actively carried on by two Institutions of the United States of
America, and by the Norwegian, Italian and French Governments. As these expetlitions
had the great advantage of profiting by the experiences of the Challenger, and were likely
to materially increase our knowledge of bathybial fishes, and to elucidate points which the
Challenger with its initial apparatus had left obscure (such as the vertical range of
pelagic forms), it seemed advantageous, in order to produce a complete account of the fish
fauna of the deep sea, to await the publication of the results of those explorations. The
hope, however, of utilizing those results for the present work became fainter, as in tlie
succeeding years only more or less fragmentary and preliminary notices appeared, with
one exception, viz., that of the valuable Report on the Fishes of the Norwegian North
Atlantic Expedition.

(ZOOL. CHALL. EXP. — PAKT LVII. — 1887.) - ^ Lll ffl

jj THE VOYAGE OF H.M.S. CHALLENGER.

One of the instructions given to me by the late Sir Wyville Thomson was, to include
in my Report not only the species collected by the Challenger, but also those which from
other sources are known to inhabit the deep sea. He agreed with me in the conclusion I
arrived at from the materials then available, that a depth of 300 or 350 fathoms should be
considered the boundary between the surface and deep-sea fishes, the fishes above that level
belouffino- principally to littoral genera, whilst those specially organized for bathybial
life appeared at or below that depth. Accordingly, almost all fishes captured by the
Challenger at a less depth than 350 fathoms were included in my Report on the Shore

Fishes.

However, the subsequent Norwegian and North American explorations brought to
liwht instances of fishes with an unmistakably bathybial organisation occurring at a much
shallower depth than the forms discovered by the Challenger, or, on the other hand,
showed that certain littoral forms descend not only to 100, but even to beyond 300
fathoms.

It consequently seemed advisable to abandon the intention of limiting this Report to
fishes occurring below 300 fathoms, and to adopt instead the 100-fathom line as the
boundary at which, with the extinction of sun-light, the bathybial fauna commences,
sporadically at first and largely mixed with surface forms. This line does not express
a sharply defined boundary any more than any other depth, but it is chosen for the
purposes of the present Report, in which a certain upper limit of the deep-sea fauna
had to be fixed. In employing it I intend only to express the fact, that no fish not
known at present to have occurred beyond the 100-fathom line, is admitted in the
present Report ; and, furtlier, that no truly bathybial fish is known to live habitually
above that line.

TABLE OF CONTENTS.

PKEFACE, . .

IISrTRODUCTIOi^,

History of our Knowledge of the Fish-Fauna of the Deep Sea,

Characteristics of Deep-Sea Fishes, ......

Vertical and Horizontal Distribution of Deep-Sea Fishes, ....

The Constitution of the Fish-Fauna of the Deep Sea, ....

Table showing the Vertical Eange of Distribution of Species, Genera, and Families,

DESCEIPTION OF GENERA AND SPECIES.
Chondropterygii.
Plagiosto.mata.

Selachoidea — Sharks, .......

Scylliidte.

Scyllium, M. and H.

canescens, Gthr., .......

Pristiurus, Bonap.

melanostomus, Raf., . . ...

Notidanidae.

Chlamydoselache, Garman.

anguinea, Garman,

Spiuacidje.

Spinax, M. and H.

spiiiax, L.

granulosus, Gthr.,
Centropliorus, M. and H.

foliaceus, Gthr., .

coilolepi^, Booage,

squamulosus, Gthr.,
Gentroscyllium, !M. and H.

fabricii, Enhidt.,

granulatum, Gthr.,
Lxmargus, M. and H.

horealu, Scoresby,
Batoidea — Rays.
Raja, Cuv.

isotrachys, Gthr.,

circularis, Couch,

PLATE

PIG

PAGE

i

xix

xxiv

xxxiii

XXX vii

xl

A 1

2

f LXIV. ... 1

] LXV. ... J

II.

A
B

4
4

5
5
5

6
7

ui.

IV

THE VOYAGE OF H.M.S. CHALLENGER.

Batoidea — Rays — continued.
Raja radiata, Donov.,
liyperhorea, Collett,
plutonia, Garman,
batis, L.,
vomer. Fries,
fulloniea, L.,
nidrosiensis, Collett,
UrolopJius, M. and H.
kaianus, Gtiir., .

HOLOCEPHALA.

Chitncera, L.

monstrosa, L.,
affinis, Capello, .

Acanthopterygii.
Percida3.

Anthias, Cuv.

megalepis, Gthr.,
Centropristis, Cuv. Val.

pleurospilus, Gthr.,
Scombrops, Schleg.

chilodipteroides, BIkr.,
Acropoma, Schleg.

philippinense, Gthr.,
Propoma, Gthr.

roseiim, Gthr.,
Malaciclithys, Doderlein.

griseus, Dod.,
Synagrops, Gthr.

japonicus, Doderlein,
Polyprion, Cuv.

cernium, Val.,
Scorpajnidse.

Scorpama, Gthr.

percoides, Solander,

dadyloptera, de la Eoche,

huhlii, Bowd,
Sebastes, Gthr.

marinus, L.,

viviparus, Kroy.,

Ttmcrochir, Gthr.,

hexanema, Gthr.,

oadatus, Gthr., .
Setarches, Johnson.

fidjiensis, Gthr., .
Bathysebastes, Steind. and Dtiderl.

albescens, St. and D.,
Lioscorpius, Gthr.

longiceps, Gthr., .

PLATE

FIG.

PAGE
8

8
10
11
11
11
11

12

12
13

13
13
14
15
15
15
16
XX, 268

17

XX, 17

xix

17
18
18
18
18

19

20

20

REPORT ON THE DEEP-SEA FISHES.

Berycidsp.

PLATE

FIG.

PAGE

Hoplostethus, C. V.

mediterranemn, C. V.,

*

21

Tradddithys, Shaw.

australis, Shaw, ....

.

22

jaclisoniensis, Macleay,

...

22

elongatus, Gthr., . . . .

. V.

c

22

fernandezianus, Gthr.,

.

...

23

traillii, Hutton, ....

. LV.

A

23

madeayi, Johnston,

24

intermedius, Hector,

. V.

B

24

darwinii, Johnson,

...

24

Anoplogaster, Gthr.

cornutus, C. V., .

25

Caulolepis, Gill.

longidens, Gill, ....

.

26

Melamphaes, Gthr.

microps, Gthr., ....

26

typhlops, Lowe, ....

. V.

A

27

megalopis, Ltkn., ....

. V.

B

27

crassiceps, Gthr., . .

. VIII.

B

28

mizolepis, Gthr., ....

28

robustus, Gthr., ....

29

heanii, Gthr., ....

29

suhorUtalis, Gill, , .

...

30

Malaeosarcus, Gthr.

macrostoma, Gthr.,

...

30

Stephanoheryx, Gill.

monx, Gill, ....

...

31

Beryx, Cuv.

decadactylus, C. V. .

xix, 33

splendens, Lowe, ....

xLx, 33

Polymixia, Lowe.

nobilis, Lowe, ....

. I.

B

34

Poromiira, Goode and Bean.

capita, G. and B.,

35

Myripristis, Cuv.

kaianus, Gthr., .

. ...

35

Trichiuridae.

Nealotus, Johnson.

tripes, Johns., ....

.

35

Aphanopiis, Lowe.

carho, Lowe, ....

. vu.

A

36

Nesiarchus, Johnson.

nasutus, Johns., ....

....

37

Lepidopus, Gouan.

caudatus, Euphrasen,

.

37

tenuis, Gthr., ....

. vn.

B

37

elongatus, Clarke,

.

38

VI

THE VOYAGE OF H.M.S. CHALLENGER.

Trichiuridfe — continued.
Triehiurus, L.

lepturus, L.
Euoxymetopon, Poey.

txniatus, Poey, .

poeyi, Gthr.,
Thyrsites, C. V.

preiiosus, Cooco, .

prometheus, C. V.,
Gempylus, Cuv. Val.

serpens, C. V., .

Carangidie.

Anomalops, Kner.

palpehratus, Boddsert,

Cyttidae.

Cyttus, Gthr.

abhreviahis, Hector,
Antigonia, Lowe.

capros, Lowe,
Diretmus, Johnson.

argenteus, Johns.,

aureiLS, Campbell,
Coryphsenidfe.

Schedophilus, Cocco.

medusophagus, Coeco,

lockingtonii, Jordan and Gilbert,

enigmatieus, Lockington,

Trachinidse.

Bathydraco, Gthr.

antarticus, Gthr.,
Aphritis, C. V.

gohio, Gthr.,
Acanthaphri/is, Gthr.

grandisquainis, Gthr.,
Gliampsodon, Gthr.

vorax, Gthr.,
Uranoscopus, L.

Icaianus, Gthr., .
Notothcnia, Rich.

mir.ops, Gthr.,

Pediculati.

Luphius, Art.

pjiscatorius, L.,

naresii, Gthr.,
Himantolopjhus, Rhdt.,

groenlandicus, Rhdt.,

reinhardti, Ltk., .
Aegxonichthijs, Clarke.

appelii, Clarke, .

PLATE

XLIII.

FIG. PAGE
39
39

39

xix, 268
XX, 268

41

41

42

44

45
45

XLIV.

VIII.

A

46
46
46

48
48
49
49
49
268

49
49
50
51
51

EEPOET ON THE DEEP-SEA FISHES.

VU

Pediculati — continued.

PLATE

FIG.

PAGE

Ceratias, Kroyer.

hispiiiosus, Gthr.,

. XI.

B

.53

holhijlli, Kroy., .

.53

uranoscopus, Murr.,

. XI.

C

.54

shufeldti. Gill,

54

canmculatus, Gthr..

. XI.

D

55

Cnjptopsaras, Gill.

couesii, Gill.,

55

Oneirodes, Liitken.

esclirichtii, Ltk., .

56

Melanocetus, Gthr.

johnsonii, Gthr., .

56

murrayi, Gthr., .

. XI.

A

57

Linopliryne, Collett.

lucifer, ColL,

57

Chaunax, Lowe.

pidus, Lowe,

. X.

A

58

Halieutxa, C. V.

sentieosa, Goods, .

59

D-ibranchus, Ptrs.

atlanticus,^ Ptrs.,

59

Cottidae.

Cotfunculus, Collett.

microps, Coll.,

. IX.

A

60

thomsonii, Gthr., .

IX.

B

61

Cottus, Art.

hathyhius, Gthr., .

. X.

C

62

Centridermichth ys, Richards.

uncinatus, Ehdt.,

.

62

Icelus, Kriiy.

hamafus, Kroy., .

63

Triglops, Reinhardt.

pingelii, Rhdt., .

.

63

Trigla, Art.

leptacantlms, Gthr.,

63

Lepidotriijla, Gthr.

spiloptera, Gthr.,

• ■•■

64

Cataphracti.

Peristethus, Lacep.

miniaium, Goode,

64

molueceme, Blkr.,

64

murrayi, Gthr., .

65

liorhynchus, Gthr.,

65

micrmieyna, Poey,

65

trmicafum, Gthr.,

.

65

Agonus, Bl. Schn.

decagonus, BI.,

. ...

65

' This fish was obtained at 360 fatlioiiis

not at 3600 fathoms, as stated in the description.

VIU

THE VOYAGE OF H.M.S. CHALLENGER.

Discoboli.

Ci/clopferus, Art.

spinosus, Miill., .
Ldparis, Art.

fabricii, Krdy., .
mteroptis, Gthr., .
ffelatinosm, Pall., .
Paraliparis, Coll.

bathyhius, Coll., .
liparinus, Goode,
memhranaceus, Gthr.,
Gobiidae.

Callionymus, L.

kaianus, Gthr., .
calaurqpomus, Eich.,
BlenniidEe.

Anarrhichas, Art.
minor, Olafs,
lafifrons, Stp.,
Blenniops, Nilss.

ascanii, Walb., .
Trachypteridae.

Tracliypterus, Gouan, .
Stylophorus, Shaw,
Regalecus, Briinn.,
Lophotidas.

Lophotes, Giorna.

cepedianus, Giorna,
cristahis, Johns., .
Acanthopterygii Pharyngognathi.
Hdiastes, C. V.
roseus, Gthr.,
Anacanthini.

Lycodidse.

Lyeodes, Reinh.

esmarMi, Coll., .
reticulatus, Rhdt.,
frigidus, Coll.,
pallidus, Coll.,
seminudus, Bwk.,
mursena, Coll.,
sarsii, Coll.,
ven-illi, G. and B.,
paxillus, G. and B.,
paxilloides, G. and B.,
Lycodonus, Goode and Bean.

mirahiUa, G. and B.,
Gymnelis, Reinh.
viridis, Fabr.,

PLATE

FIG. PAGE

66

XI.

XII.

XII.

...

66

B

66

...

67

C

68

68

D

69

70

70

70

71

XIII.

71

72
73
73

76

76

76

77
77
79
79
79
79
80
80
81
81

81

EEPORT ON THE DEEP-SEA FISHES.

IX

Lycodidse — continued.
MelanosHgma, Gtlir.
gelatinosum, Gthr.,

Gadidae.

Gadus, Art.

moirMia, L.,

minutus, L.,

poutassou, Eisso,

argenteus, Guich.,
Mora, Risso.

mediterranea, Risso,
Halargyreus, Gtlir.

johnsonii, Gthr., .
Melanonus, Gthr.

gracilis, Gthr.,
Mei-luccius, Cuv.

vulgaris, Flem., .
Hypdcometes, Goode.

gohioides, Goode, .
Lotella, Kaup.

marginata, Gthr.,
Uraleptus, Costa.

maraldi, Eisso, .
Physicuhis, Kaup.

dalioigkii, Kaup.,

Jcaupi, Poey,

peregrinus, Gthr.,
Phycis, Cuv.

hlennioides, Briinn.,

chesteri, G. and B.,

regius, Walb.,

americanus, Bl., .

tenuis, Mitch.,
Lsemonema, Gthr.

harhatidum, G. and B.,
Haloporphyrus, Gthr.

guentheri, Gigl., .

lepidion, Risso, .

eques, Gthr.,

inomnee, Gthr., .

ensiferus, Gthr., .
Antimora, Gthr.

rostrata, Gthr.,

viola, G. and B., .
Salilota, Gthr.

australis, Gthr., .
Molva, Nilss.

molva, L.,

ahyssorum, Nilss.,

(ZOOL. CHALL. EXP. PART LVII. — 1887.)

PL.^TE FIG. PAGE

82

XIV.

XIV.

XVII.

82
xix

82
83

83

83

84

85

86

86

XX, 87

88
88
88

89
89
89
89
89

90

XVIII.

A

90
91

XVIII.

B

91

XX.

B

92

XIX.

A

92

XVI.

A

93

XV.

94

XVII.

95

96
9G

LIl h

THE VOYAGE OF H.M.S. CHALLENGER.

Gadidae — continued.
Onus, Eisso.

macrophthahnns, Gthr.,

carpenteri, Gthr.,

reinJiardti, Coll., .

septentrionalis, Coll.,

ends, Enh.,

cimbrius, L.,
Brosmms, Cuv.

hrosme, Miill.,
Chiasmodus, Johns.

nir/e); Johns.,
Ophidiidje.

Baraihrodenms, G. and B.

manatinus, G. and B.,
Neobytliites, Goode and Bean.

grandis, Gthr.,

macrops, Gthr., .

ocellatus, Gthr., .

gillii, G. and B., .
Cateehjx, Gthr.

mesderi, Gthr., .
Pteridium, Scopoli.

atrum, Eisso,
Pteroidonuf, Gthr.

quinquarius, Gthr.,
Dicrolene, Goode and Bean.

intronigra, G. and B.,
Mixonus, Gthr.

laticeps, Gthr.,
Bathyonus, Gthr.

compressus, Gthr.,

txnia, Gthr.,

catena, G. and B.,
Porogadus, G. and B.

gracilis, Gthr., .

miles, G. and B., .

rostratus, Gthr., .
Nemaionus, Gthr.

2)ectoralis, G. and B.,
Diplacanthopoma, Gthr.

hrachysoma, Gthr.,
Acanthmius, Gthr.

armatus, Gthr., .
Typhlonus, Gthr.

nasus, Gthr.,
Aphyonus, Gthr.

gelatinosus, Gthr.,
RliodicMhys, CoUett.

regina, Coll.,

PLATE

FIG.

PAGE

96

. XLII.

D

97

. XIX.

B

97
98
98
98

98

99

100

XXI.

A

100

. XX.

A

102

XXI.

B

lO.S
103

. XXIII.

B

104
10.5

XXII.

B

106
107

. XXV.

B

108

. XXII.

A

109

. XXIII.

A

110
111

. XVI.

B

112
113

. XXIV.

B

113
114

. XXIII.

C

115

XXIV.

A

117

. XXV.

A

119

XXVI.

A

120
121

REPORT ON THE DEEP-SEA FISHES.

XI

Ophidiidse — continued.
Ophidiuin, Cuv.

mursmolepig, Gthr.,

Macruridae.

Macrurus, Bl.

( CcBlurliynch us),
parallelus, Gthr., .
japonicus, Schleg.,
austrcdis, Rich., .
ajelorhijnclius, Risso,
camiinatus, Goode,
fasciatus, Gthr., .

{Macrurus).
fabricii, Sundev.,
rudis, Gthr.,
nasutus, Gthr.,
serrulatus, Gthr.,.
sclerorhijnclius, Vul.,
sequahs, Gthr.,
hairdii, G. and B.,
goodii, Gthr.,
holotracliys, Gthr.,
asper, Gthr.,
carinatus, Gthr., .

( Coryph senoides) .
mjiestris, Gunn., .
altipinnis, Gthr., .

(Mystacojumis).
lonfjiharhis, Gthr.,
italicus, Giglioli, .

{lAonurus).
Jiltcauda, Gthr., .
rnicrolepis, Gthr.,

(Trachonunis).
irillosus, Gthr.,

(Cetonurus).

crassiceps, Gthr., .

(ChaUnurus).

leptulepis, Gthr., .
dniulus, G. and B.,
fernandezianus, Gthr.,
liocephalus, Gthr.,
murrayi, Gthr., .

(Optonurtis).

denticulafus, Rich.,

(Malacocejihalus).
Isevts, Lowe,
macroehir, Gthr.,
sulcatus, G. and B.,

PLATE FIG. PAGE

268

XXIX.

A

125

XXIX.

C

127
127

xix

,128

L.

B

129

xxvm.

A

129
130

XXVII.

131

XXX.

B

132

XXX.

A

133

XXXII.

A

133

XXXII.

G

134

XXXII.

B

135
136

xxvm.

B

136

XXXVI.

A

137

XXXUI.

A

137
138

XXXIX.

A

138

XVIII.

C

139
140

XXXIV.

B

141
142

XXX VI.

XXXVII.

142

143

XXXI.

144
145

XXXVIII.

B

145

xxx^^II.

A

145

XXXIV.

A

146

147

XXXIX.

B

148

XXIX.

B

148
149

xu

THE VOYAGE OF H.M.S. CHALLENGER.

Macruridse — continued.

PLATE

FIG.

PAGK

{Nematonurus).

armatm. Hector, ....

. XL.

A

150

affinis, Gthr., ....

. XL.

B

151

longiJUis, Gtlir., ....

. XXXV.

151

Trachyrhynclms, Giorna.

iracliyrhytichus, Eisso,

. XLI.

Cxix,152

longirostris, Gtbr.,

. XLI.

B

153

mmrayi, Gthr., ....

. XLI.

A

153

Batliygadus, Gthr.

cottoides, Gthr., ....

. XLII.

A

154

multijilis, Gthr., ....

. XLII.

B

155

cavei-nostis, G. and B., .

156

macrops, G. and B.,

.

...

156

lotKjifilis, G. and B., .

157

Macrworms, Gthr.

novx-zelandiss, Hector,

. ...

157

Lyconidse.

Lyconus, Gthr.

pinnatus, Gthr., ....

. XLII.

C

15S

Ateleopodidse.

Ateleojjus, Schleg.

japonicus, Blkr., .

PleuronectidcT.

Hippoglossiis, Cuv.

piiiguis, Fabr.,
Hippoglossoides, Gottsche.

platessoideg, Fabr.,
Pcecilopsetta, Gthr.

colorata, Gthr., .
AnticithariLs, Gthr.

p)olyifpiJus, Gthr.,
Samaris, Gray.

inaculatus, Gthr.,
Lepidopisetta, Gthr.

maculata, Gthr., .
Pseudorhombus, Blkr.

hedoris, Gthr.,

boojis, Hector,

oMongus, Mitch., .

ocellatus, Gthr., .
Rhomboidich thys, Blkr.

cornutus, Gthr., .
Moiwlene, Goode.

sessilicauda, Goode.
Citharich thys, Blkr.

areti/rom, Goode,

unicornis, Goode,

159

161

161

162

162

162

162

163
164
164
164

165

165

165
166

REPORT ON THE DEEP-SEA FISHES.

XUl

Pleuronectidse — continued.
Pleuronectes, Gthr.

heanii, Goode,

ajnoglossus, L., .
Nemataps, Gthr.

microstoma, Gthr.,
' Solea, Gthr.

Icaiana, Gthr.,
Aphoristia, Kaup.

nebulosa, G. and B.,

Physostomi.

Sternoptychidse.

Arr/i/ropelecus, Cocco.
hemigymniis, Cocco,
olfeu'di, Cuv.,

Stei'uopitijx, Herm.

diaphana, Herm.,

Polyi2mu8, Gthr.
S2^!7ll>s1ls, Gthr.,

Gonostuma, Rafin.
denudatum, Raf.,
eIo7i(jatum, Gthr.,
(jracile, Gthr.,
microdon, Gthr., .

Photichthi/s, Hutton.
argenteus, Hutton,

Chauliodus, Bl. Schn.
sloanii, Bl. Schn.,
Scopelidae.

Saums, G. V.

liaianu!<, Gthr., .

Harpodon, Les.

microchir, Gthr., .

Bathijsaurus, Gthr.
ferox, Gthr.,
mollis, Gthr.,

Batlujpterois, Gthr.

longifilis, Gthr., .

longijies, Gthr., .
longicauda, Gthr.,
qtiadrifilis, Gthr.,

Ipnops, Gthr.

muiTayi, Gthr., .

Chloropldhalmus, Bonap.
agaaifkii, Bonap.,
jvoductus, Gthr., .
nigripinnis, Gthr.,
gracilis, Gthr.,

PLATE

SLVII.

FIG. PAGE
166

166

166

... 167

... 167

167

167

XLV.

D

169
170
172

XLV.

B

173

.\LV.

C

174

175

XLV.

A

178
179

180

180

XLVI.

A

181

XLVI.

B

18:5

XLVII.

^\

185

XLVIII.

Bf

xLvin.

A

188

XXVL

V,

188

XXXIU.

B

189

191

L.

C

192

L.

D

193

LI.

A

193

XUX.

A

194

XIV

THE VOYAGE OF H.M.S. CHALLENGER.

Scopelidce — continued.
Scopelus, Gthr.

macrolepidotus, Johns.,
glacialis, Eeinli., .
antardicus, Gtlir.,
engraulis, Gthr., .
dumerilii, Blkr., .
NamiohracMurn, Gthr.

nigrum, Gthr.,
Odontostonms, Cocco.

lu/alinus, Cocco, .
Omosudin, Gthr.
lowii, Gthr.,
Plagijodus, Steller.
ferox, Lowe,
assculapius, Bean,
altirelis, Poey,
hm-ealis, Gill,
StomiatidEe.

AstronesiJies, Kich.

niger, Rich.,
Stomias, Guv.
boa, Risso,
affinis, Gthr.,
ferox, Eeinh.,
Echiostoma, Lowe.

harhatum, Lowe, .
Oposfomias, Gthr.

micripnus, Gthr., .
Pacliystomias, Gthr.

microdon, Gthr., .
Photonectes, Gthr.

alhipinnis, Doderl.,
Malacosteus, Ayres.
nigei; Ayres,
indicus, Gthr.,
Batlwpliihis, Giglioli.

nigerrimus, Gigl.,
Idiacanthus, Ptrs.
fascioJa, Ptrs.,
ferox, Gthr.,
Salmonidse.

Argentina, Art.
silus, Cuv.,
spliyrxna, L.,
liogJossa, C. V., .
elongata, Hutton,
Microstoma, Cuv.

rotundatiim, Eisso,
groenlandicum, Knhrdt.,

PLATE

FIG.

PAGE

196
196

LI.

D

196

LI.

C

197
198

LII.

B

199

LII.

A

200

HI.

C

201

203
203
203
203

LII.

203

204

LIV.

A

205
205

LIII.

B

206

LIII.

A

208

LXII.

C

210
212

LIV.

C

214

LIV.

B

214

215

215

D

216

217

217

217

217

219

...

219

KEPORT ON THE DEEP-SEA FISHES.

XV

Salmonidse — continued.

Bathijlagug, Gthr.

atlanticus, Gthr., .
aniarticus, Gthr., .
Bathythrissidas.

Batltythrissa, Gihi.
dorsalis, Gtkr.,
Alepocephalida3.

Alepocephalus, Risso.
rosiratus, Risso, .
agasdzii, G. and B.,
productus. Gill, .
bairdii, G. and B.,
niger, Gthr.,

Bathytrodes, Gthr.
inacrolepis, Gthr.,
mirrolejns, Gthr.,
rostratus, Gthr., .

Platytrodes, Gthr.
apus, Gthr.,

Xenodermidithys, Gthr.
nodulosvs, Gthr., .
Halosauridfe.

Halosaurus, Johns.
otoenii, Johns.,
niaerodiir, Gthr.,
mediorostris, Gthr.,
rostratus, Gthr., .
affinis, Gthr.,
Notacanthi.

Notacantlius, Bloch.
{Notaca7ithus).

sexspinis, Rich., .

nasus, BL,

phasganorus, Goode,
honapaHii, Risso,
{Polyacantlionotus).

rissoamus, FU. and Ver., .
MurajnidtB.
Anguillina.

Congromurxna, Kaup.
guttulaia, Gthr., .
SimendieJys, Goode and Bean.
parasiticus, G. and B.,
Mursenesocina.
Nettastoma, Raf.

meJanurum, Raf.,
parciceps, Gthr., .
procerum, Goodo and B.,

PLATE

( LX.
1 LXI.

LI.

FIG. PAGE

... 219
... 220

222

xix,

223
223
223
224
224

LVII.

B

225

LVII.

A

226

I;VIII.

B

227

Lvin.

A

229

LVIIl.

C

230
236

LIX.

A

237

LIX.

C

239

LIX.

D

240

LIX.

B

240

B

243

9-15 )
A /
... 248
... 249
C 249

Lxin.

250

252

252

253
253
253

XVI

THE VOYAGE OF H.M.S. CHALLENGER.

LXII.
LXII.

LXIII.

LXVI.

LXIII.

A

B

C

Synapliobranchina.

Synaphohranchus, Jolins.

pinnatus, Gronov., . • ■ •

hathyhius, Gthr., . . • • •

iiifernalis, Gill, . . . • •

hrevidorsalis, Gthr., . - • •

Saecopharyiigina.

Saccoptharynx, Mitchill.

ampullaceus, Harwood, . . . •

pelecanoides, Vaill., . . • •

bairdii, Gill and Eyder, ....
Nemiclithyina.
NemicMliys, Rich.

scolopacea. Rich., ....

avocetta, Jord. and Gilb.,

infans, Gthr., . . . . ■

Cyema, Gthr.

atrum, Gthr., .....

Plectognathi.

Triacanthodes, Blkr.

anomalus, Schleg., . . . • ■ ....

Monacanihus, Cuv.

fessellatus, Gthr., . . . . . ....

Cyclostomata.

Myxine, L.

r/Iutinosa, L., . . . . • . ....

atistralis, Jen., . . . . . . ....

APPENDIX A.,

Report on the Structure of the Peculiar Organs in the Head of Ipnops. By Professor H. N.
Moseley, F.R.S.

APPENDIX B.,

Report on the Structure of the Phosphorescent Organs of Fishes. By R. von Lendenfeld,
Ph.D., F.L.S.

FIG. PAGE

B
D

253
•254
254
255

256
262
262

263
263
264

265

26G
267

267
267

269

577

INTRODUCTION.

The materials which form the subject of this Report cousisted of 794 specimens, of
which 610 were obtained during the voyage of the Challenger, 88 on the cruises of the
"Knight Errant " and " Triton," and 96 from various other sources. These specimens
are referred to 266 species, 177 falling to the share of the Challenger, and 14 being due
to the exploration of the Fseroe Channel. The number of new forms discovered by the
Challenger amounts to 144, whilst by the deep-sea exploration of the Fseroe Channel
ten species were added to the fauna of the British Seas.

The latter possess, perhaps, the greatest interest to the student of the British marine
fauna; they verified the supposition which had been entertained for some time, viz.,
that fishes distinct from those of the littoral fauna inhabit the depths of the ocean
surrounding the British Islands. At a time when so much attention is paid to the
investigation of the marine products of the British Seas, it may be hoped that the hitherto
intermittent efforts of exploring the deeper parts of this ocean may be prosecuted in
as systematic a manner as the explorations carried on on the American side of the
Atlantic, where the United States Government has spared no expense to secure the rich
harvest that was to be expected not only for the advancement of knowledge, but also
for the direct benefit to the country.

The majority of the Challenger specimens were at least externally in a very good state
of preservation ; those fishes only which possess bones, integuments, or fin-rays of a soft or
delicate texture, and thin deciduous scales, naturally suffered more or less through being
dragged to the surface from a depth of 1000 and more fathoms. Such specimens can
reach the surface in perfect condition only under exceptional circumstances. However,
with few exceptions, even the specimens of delicate structure were sufficiently well
preserved to enable us to recognise their original shape and the arrangement of their
scales, and to reproduce them in what are believed to be tolerably accurate figures.
Unfortunately the abdominal organs were only too frequently found to be destroyed, or
had suffered too much by laceration and decomposition to admit of examination. This
was especially the case in those provided with an air-bladder, which was almost invariably
torn into mere shreds. The stomach was nearly always empty. This condition of the
specimens, combined with the circumstance that many of the new types were represented

(ZOOL. CHALL. EXP. PAET LVII. 1887.) Lll ''■

xviii THE VOYAGE OF H.M.S. CHALLENGER.

only by one or two examples, which have to be kept intact for the use of future investi-
gators, must account for the scanty information which I am able to give with regard to
their internal structure.

In some of the specimens the so-called phosphorescent organs were well enough
preserved for microscopical examination, and having always held the opinion that
the function of all these organs was to produce light, an opinion which has been partly
or wholly opposed by Leuckart, Ussow and Leydig, I was particularly anxious that as
much as possible of the materials of the Challenger should be utilized for a thorough
histological investigation of these organs by zoologists thoroughly versed in the method
of histological research. Mr. Murray acceded without hesitation to this proposal, and it
was hoped that Professor Moseley would undertake the whole of this investigation ; but
as he was compelled by other duties to limit himself to the examination of the remarkable
organs in the genus Ipnops, the remainder were entrusted to Dr. von Lendenfeld. The
reports of both these gentlemen will be found in the Appendices to the descriptive
report.

My technical descriptions of the Challenger fishes will be found to be much more
concise than those given by some recent writers on similar subjects, and will appear to
some to be too short. In my own experience, the practice of circumstantially describing
every minute detail of the surface of a fish, repeating every jioint of structure
common to all the species of the genus or famdy, and indiscriminately mixing
individual features with specific, not only renders the use of these lengthy descriptions a
laborious and thankless task, but actually leads to misunderstandings not less frequently
than insufficient short diagnoses prepared by inexperienced describers. In fact, in several
instances I have found that the descriptions which I published some ten years ago as
" preliminary diagnoses," express so fully the specific characters of the fishes as to render
any additions to them superfluous.

REPORT ON THE DEEP-SEA FISHES. xix

HISTORY OF OUE KNOWLEDGE OF THE FISH-FAUNA OF THE DEEP SEA.

Isolated examples of Deep-Sea Fishes had fallen into the hands of zoologists at an
early period of systematic ichthyology ; thus, specimens of Trachyi^terus, Regalecus,
Saccopteryx, Stylojjhorus, Plagyodus, and other genera were known to and described by
zoologists of the last century. But, having been captured whilst floating on the surface or
near to the coast, they were regarded merely as extremely scarce creatures, without any
clear idea being entertained that they were stray individuals from the unknowoi depths
of the ocean. Risso was the first to distinguish a bathybial fish-fauna, assigning to it
certain fishes and stating the depths at which they habitually live. In enumerating^ the
various regions of the Gulf of Genoa he states — " Les grands abimes de la mer ne sent
frequentes que par les alepocephales, les pomatomes, les chimeres et les lepidolepres.
Les profondeurs moindres sont la demeure habituelle des merlans, des molves, des phycis,
des soldados, des citules, des serioles, des tetragonures, des castagnolles, etc." He states
exactly the depths inhabited by several fishes : thus Alepocephcdus rostratus occurs at a
depth of 2000 feet or more (350 fathoms), Tracliyrhynchus trachyrhynchiis and
Macrurus ccelorhynchus at a depth of 1500 or 1800 feet (250 or 300 fathoms) "ou parait
constamment regner une temperature de dix degres," Uraleptus maraldi at a depth of
1000 feet (170 fathoms), and Gadiis minutus (Morua capelantis) at a depth of
300 metres (150 fathoms).

During his numerous and prolonged visits to the Island of Madeira the Rev. R. T.
LowE^ paid special attention to the wonderful variety of the fishes of the sea surrounding
that island. He discovered a number of new forms, the bathybial habits of which were
ascertained, either by himself at the time of their discovery, or subsequently by others
who studied the subject after him. In his History of the Fishes of Madeira, the five
parts of which appeared at irregular intervals between the years 1843 and 1860, and
which unfortunately remained unfinished, he gives the precise depths at which several
species occur, viz., Beryx splendens, "which begins to be met with, of small size, at a
depth of 150 or 200 fathoms, but is scarcely ever taken in full size and abundance, except
with its congener, Beryx decadactylus, the Alfonsin a caste larga, at the enormous depth
of from 300 to 400 fathoms, and from one to two leagues from shore " ; Scorpgena kuhlii,
the "Requeime," which is "caught with lines of from 100 to 250 fathoms"; Thyrsites

' Histoire naturelle des principales productions de I'Europe m<5ridionale, vol. 'iii., Paris, 1826 ; Introduction,
page .X.

2 He left England with liis vdk in April 1874 for his last journey to Madeira, which he never reached again.
The steamer " Liberia," in which he had taken his passage, foundered in the Bay of Biscay, not a soul being saved of
the passengers and crew. To him and to his successor in the field of Madeiran ichthyology, Mr. J. Y. Johnson, I
owe a debt of gratitude for the encouragement and help they gave me at an early period of my ichthyological studies.

XX THE VOYAGE OF H.M.S. CHALLENGEE.

pretiosus, the "Escolar," which "is taken with an ordinary bait at a depth (the fishermen
affirm) of from twelve to fourteen linlias ( = 300-400 fathoms), living habitually near the
bottom, in company with the Cherne (Polyprion cernium), Ccelho (Thyrsites prometheus
or Prometheus atlanticus), etc."; Thyrsites pivmetheus, which "lives habitually at the
bottom, and is taken at most seasons in a depth of from 100 to 300 or 400 fathoms";
Scorpsena dactyloptera, from 250 to 400 fathoms. Especially instructive is Lowe's
account of the capture and occurrence of Polyprion cernium ; he says : —

" The Sherny in Madeira is only captured by the hook ; and though shoals of small
fishes, weighing from five to twenty pounds, and called Chernotta, are said to be often
taken near the surface, in the neighbourhood of floating wreck or logs of wood, the
proper habitat of the full-sized fish, weighing from thirty to one hundred pounds, is
from one to two or three leagues from shore, and at the enormous depth of from twelve
to fifteen or sixteen linhas, or from three hundred to four hundred fathoms. With a
strong line^ of this length, to the bottom of which is tied a stone (called the ' pendula')
of three or four pounds' weight, and having attached immediately above the stone, at
intervals of eighteen inches, from twelve to fifteen strong hooks, baited with pieces of
Cavallo [Mackerel] or Chicharro [Madeiran' Horse-Mackerel], I have been frequently
assisting at their capture. Coming up from these enormous depths, the fish becomes so
distended with gas, expanding upon the removal of the vast pressure below, that it rises
to the surface, not indeed entirely dead, but wholly powerless, and in a sort of rigid
cataleptic spasm ; the stomach is usually inverted, and protruded into the mouth ; and
thu eyes in general are forced so completely from their sockets, sticking out often like
two horns, that ' eyes like a Cherne ' is a common phrase amongst the fishermen for a
prominent-eyed person. Sometimes, from the same cause, it rises faster as it aj^proaches
the surface than the line can be hauled in, shooting quite out of the water at some
distance from the boat upon its first emergence, like a cork or bladder, from the
lightness caused by its great distension. The usual size of these was from two and a
half to three and a half feet long, weighing from twenty-five to forty or fifty pounds."

The discovery that some fishes live, at an early period of their existence, at or near
the surface, and in the course of their growth retire into the depths of the ocean, is due
to Lowe.

The study of the fishes of Madeira was continued by Mr. J. Y. Johnson, who,
between the years 1862 and 1866, made some of the most interesting additions to
ichthyology; he discovered important bathybial types, such as Chiasmodus, Melano-
cetus, Halosaurus, Synaphohranchus, the Saccopharynx of Mitchell, and others, but
he treated them like any other rare surface-fishes, without taking note of their pertinence
to a distinct fauna.

Each boat is generally furnished with two such lines, each worked by a single fisherman, who is, however,
assisted by others in the labour of hauling in the line, which takes from twenty to thirty minutes.

EEPOET ON THE DEEP-SEA FISHES. xxi

Lowe as .well as Jolmson deposited their treasures in the British Museum, and from
these materials chiefly I formed the idea of a special adaptation of the ichthyic type to
Imthybial life. The comparison of fishes so widely different as Plagyodus {Ale2ndo-
saurus), Eegaleacs, Tr achy icterus, Stylophorus, Saccopharynx, Chiasmodus, Melano-
cetus, showed nevertheless a singular agreement in important points of organisation,
and even in the circumstances under which their capture took place. And having
recognised that the diminished amount of earthy matter in the osseous system, the
extreme thinness of the muscular layers of the trunk and tail, the easily ruptured
connective ligaments and tissues of the muscles and bones, the increase in size or
degradation of the organ of sight, the distensibility of the stomach, the shrinking of
the gills, the development of the muciferous system with or without special organs of
'■•luminosity, the black coloration of the pharynx and peritoneum, were peculiarities
which, either singly or combined, either by themselves or in connection with other
evidence, indicated the bathybial nature of the fish, I relegated to tlie deep-sea fauna
Plagyodus in 1860, the Trachypteridse and Lophotidae in 1861, Halargyreus and
Saccopharynx in 1862, Melaviphaes, Melanocetus, Chiasmodus, a part of the Sternopty-
chidse, Scopelidas and Stomiatidse in 1864, the Halosauridse in 1866, Pseudophycis in
1867, and Synaphobranchus in 1870.^

I had no definite information at the time with regard to the depth at which these
types habitually live, but I thought it probable that some of them descend to much
greater depths than were recorded hitherto, and that the degree of adaptation to a
bathybial life increased with the depth reached by the fish ; in fact, that the successive
vertical zones of the deep sea were inhabited by fishes of a different and peculiar
organisation. This last surmise has not been verified by the facts obtained during the
Challenger and subsequent expeditions. But I ascertained, at a time previous to the
British Deep-Sea expeditions,^ that deep-sea fishes must have a wide horizontal range,
and that consequently the physical conditions of the depths of the ocean must be the
same or nearly the same over the whole globe, — a fact already recognised by Risso,
though his observations were limited to the district of the Gulf of Genoa (vide supra,
p. xix.).

The materials brought home by the Challenger laid a .broad and sure foundation
of our knowledge of the abyssal fish-fauna, and the preliminary notices of the new and
remarkable forms which were published in the years 1877 and 1878^ could not fail to
draw the attention of the succeeding explorers of the deep sea to this class of animals.

1. Of the three Norwegian North Atlantic expeditions undertaken in the years
1876, 1877, and 1878, the last furnished much information as regards the deep-sea

1 See Cat. Fish., under the headings of the genera enumerated ; Proc. Zool. Soc. Land., 1864, p. 301 (^Melanocetus);
Proc. Zool. Soc. Land., 1866, p. 336 (Ausonia).

» Cat. Fish., vol. v. p. 420, 1864. ^ ^,j„_ ^nd Mag. Nat. Hist., 1877, vol. x.\., and 1878, vol. ii.

xxii THE VOYAGE OF H.M.S. CHALLENGER.

fishes of the Polar Sea. The sea between Hammerfest and Varanger Fjord, that
extendinty towards Novaja Zemlja and Jan Mayen, and northwards to the north-western
extremity of Spitzbergen, were explored. The greatest depth reached by the trawl
was nearly 1400 fathoms. About thirty species were collected, of which those of the
o-enera Lycodes and Lijjciris, and the genus Rliodichthys are of particular interest. In
an elaborate Eeport by Robert CoUett these fishes are described in detail and well
figured.^

2. Thanks to the exertions of Professor A. Agassiz and Dr. Spencer Baird, the
Government of the United States j^rovided, at first by the loan of ships, and later
through the organisation of the U.S. Commission of Fish and Fisheries, for a s5'-ste-
matic exploration of the depths of the Western Atlantic. Omitting the earliest opera-
tions, in which no special attention was paid to deep-sea fishes, we have to mention, in*
the first place, the successful trips of the U.S. steamer " Blake," under the command of
Lieut. -Com. C. D. Sigsbee and Commander J. N. Bartlett, in the years 1878 to 1880,
to the Gulf of Mexico and the Caribbean Sea. The dredging and trawling apparatus
used by the Challenger was improved, and in order to ascertain the nature of
the fauna at any given depth intermediate between the surface and bottom. Com-
mander Sigsbee introduced an apparatus, which works in a vertical, instead of hori-
zontal, direction, and which admits animals only at a desired depth. Whatever
importance may be attached to the results obtained by it with regard to the distribution
of the lower animals, the fact that this apparatus failed to capture any fishes in mid-
water is evidence of but negative value. The investigation of the bottom revealed
areas devoid of and others rich in animal life, and the causes of such abundance or
poverty were approximately ascertained. The operations of the U.S. Fish Commission
had to be conducted chiefly with the direct object of developing the commercial
resources of the country, but as this object goes hand in hand with, and as its
attainment is in great measure dependent on, strictly scientific research, the work
of the Commission was carried on in both directions. From the year 1877 the
Commission was enabled, by the possession of a suitable steamer, the "Fish-Hawk,"
to engage in deep-sea operations, chiefly in parts of the Atlantic north of the area
surveyed by the " Blake," but occasionally extending southwards into the West Indian
Sea, as, for instance, those of 1884 by the U.S. steamer "Albatross." These explora-
tions, which were systematically carried out with sound judgment and intimate
knowledge of the requirements for deep-sea operations, yielded adequate results ; no
other part of the ocean is now better known, with regard to its marine products,
than the Atlantic coasts of the United States and the deep water outside the littoral
zone. The contributions to the fauna of deep-sea fishes were numerous and of
great interest, and have been described chiefly by Messrs. Brown Goode and

1 Deu NorsL-e Nordhavs-Expedition, Zoologie. Fiske. Christiania, 1880, 4°.

REPORT ON THE DEEP-SEA FISHES. xxiii

Bean, whose publications will be duly referred to in the descriptive part of this
Eeport. So far as the materials have been worked out, they show that fishes recorded
by the Challenger from great depths live in much shallower water in other parts of the
ocean, and that, on the other hand, many littoral forms descend to within the vertical
limits of the deep-sea fauna. The greatest depth from which the capture of fishes is
reported was 2900 fathoms, nearly the same as that stated by the Challenger.

3. By the explorations of the Faeroe Channel, in H.M.SS. "Knight Errant" and
"Triton," in the years 1880 and 1882, our knowledge of the deep-sea fishes between
the British Islands and the Polar Sea was much advanced ; in fact, nothing was known
previously about this district. The trawl was used in from 200 to 640 fathoms.^ All
the species collected are embodied in the present Report ; they proved to be partly
identical with those collected by the Norwegian expedition, and partly closely allied to
types which were previously known from the Mediterranean.

4. The deep-sea explorations undertaken by the French Government, and entrusted to
a commission under the presidency of Professor Milne-Edwards, began in the year 1880.
A vessel, " Le Travailleur," was employed for short periods in three consecutive years,
and replaced by the larger " Talisman" in 1883. The field of operations was in the first
years the Bay of Biscay, and extended to the Mediterranean and the Canary Islands, but
stiU more work was done in the "Talisman," in which the expedition made a series of
observations ofi" the coast of Morocco southward to Cape Verde Islands and the Sargasso
Sea, and westward to the Azores. From the general reports published it would appear
that the materials collected contain important contributions to our knowledge of deep-sea
fishes, but no authentic information has been published, with the exception of a supposed
new genus, Eurypliarynx.

5. The Italian Government despatched a ship of the Royal Navy, the " Washington,"
in three consecutive years (1881-3) for the exploration of the depths of the Mediterranean.
With regard to abyssal fishes, these expeditions were somewhat barren in results.

' StafY Commander Tizard, R.N., and John Murray, Exploration of the Faaroe Channel, during the summer of 1880
in H.M.'s hired ship " Knight Errant," Proc. Roy. Soc. Edin., 1882. • ^

xxiv THE VOYAGE OF H.M.S. CHALLENGER.

CHARACTERISTICS OF DEEP-SEA FISHES/

The physical conditions under which fishes live at a depth of 100 and more fathoms
affect certain parts of their organisation. We know now, chiefly from the Norwegian
and North America explorations, that many littoral fishes descend within the limits of
the truly abyssal fauna. These descents, however, are not permanent removals from
the littoral zone, but, at the most, periodical ; and therefore no conspicuous change in
any of the organs of these fishes has taken place. But already, in many fishes which
permanently reside at from 80 to 120 fathoms, we find indications of their habitat in the
black coloration of their pharynx and in the size of their eye, which is proportionally
laro-er than in their representatives at the surface. In the true deep-sea fishes
certain organs are so conspicuously modified that every one of these fishes may be
recognised as a deep-sea fish, without accompanying positive evidence of its capture at a
great depth ; and vice versa, fishes reputed to have been obtained at a great depth, and
not having any of the characteristics of the dwellers of the deep sea, must be regarded as
surface fishes. The question whether the amount of modification is proportioned to the
depth, must be negatived from the evidence at present available, inasmuch as deep-sea
fishes caught at depths of between 300 and 400 fathoms may show a much more con-
spicuous development of abyssal peculiarities than those from 2000 and more fathoms.

The tremendous pressure under which deep-sea fishes live must be one of the primary
causes affecting their organisation. The pressure of the atmosphere at the level of the
sea amounts to fifteen pounds per square inch of the surface of the body of an animal ;
but below the surface of the ocean the pressure is increased to a ton weight for every
1000 fathoms of depth. In many deep-sea fishes we find, then, that the osseous or
muscular systems, or both, are, as compared with the same parts of surface fishes, very
feebly developed, as for instance in the Trachypteridse, Melanocetus, Chiasmodus,
Plagyodus, Omosudis, Saccopharynx. The bones have a fibrous, fissured and cavernous
texture, are light, with scarcely any calcareous matter, so that the point of a fine needle will
readily penetrate them without breaking. In some the primordial cartilage is persistent
in a degree rarely met with in surface fishes, and the membrane bones remain more or
less membranous or are reduced in extent, like the operculum, which frequently is too
small to cover the gills. When the fish is brought to the surface, all the bones, and
more particularly the vertebrse, are most loosely connected with one another. Likewise
the muscles, especially the great lateral muscles of the trunk and tail, are ihin ; the
fascicles can be readily separated or torn, the connective tissue being extremely loose and

1 The contents of this chapter formed the subject of a lecture delivered at Cambridge in 1874, and of the notes
published in Introduction to a Study of Fishes, 1880, p. 296.

REPORT ON THE DEEP-SEA FISHES. XXV

feeble, so that the specimens require the most careful handling to prevent their breaking
up into fragments. This condition appears to obtain in the highest degree in a fish
allied to Plagyodus, and occurring in the Madeiran Sea, of which Lowe succeeded in
obtaining fragments only. Specimens of this fish are sometimes caught on long lines at
great depths, but before they can be hauled to the surface, the body breaks away, leaving
fragments only on the hook.^ We cannot assume that this loose connection of the osseous
and muscular systems obtains whilst those fishes remain under the normal physical
conditions of their abyssal abode. All are carnivorous, and some of them most rapacious
creatures, which must be able to execute rapid and powerful movements to catch and
overpower their prey ; and for that object their muscular system, thin as its layers may
be, must be as strong, and the chain of the segments of their vertebral column as firmly
linked together, as in surface fishes. In coming to the surface their body has undergone
a change which is merely due to their rapid withdrawal from the pressure under which
they lived ; it is a much aggravated form of the afiection that is experienced by persons
reaching great altitudes in a balloon, or by the ascent of a mountain. In every living
organism with an intestinal tract there are accumulations of free gases ; and, moreover,
the blood and other fluids, which permeate every part of the body, contain gases in
solution. Under greatly diminished pressure these gases expand, so that, if the with-
drawal from a depth is not an extremely slow and gradual process, the various tissues
must be distended, loosened and ruptured ; and what is a vigorous fish at a depth of 500
or more fathoms, appears at the surface as a loosely-jointed body, which, if the skin is not
of suflicient toughness, can only be kept together with difliculty. At great depths a
fibrous osseous structure and a thin layer of muscles suffice to obtain the same results for
which, at the surface, thickness of muscle and firm osseous tissue are necessary.

The singular circumstance that the first two specimens known of Saccopteryx, two of
Ghiasmodus, and one of Omosudis were picked up floating on the surface, dead or in a
dying condition, with their stomach distended by a large recently swallowed prey, can be
easily explained by the aid of those phj^siological facts. If, during the struggle which
must take place between the attacking fish and its prey, the fishes are carried out of their
depth into a somewhat higher stratum, the expansion of the gases will cause both to
ascend towards the surface, especially if one of them be provided with an air-bladder, and
the rate of speed of the ascent will increase the nearer they approach the surface, which
they reach dead or in a dying condition, as witnessed and described by Lowe {vide supra,
p. XX.). Occurrences of this kind must happen very often, as, of course, comparatively
few can by accident fall under the observation of naturalists.

In a slight degree the phenomenon described is a matter of every day occurrence,
well known to fishermen who fish at depths of from 40 to 80 fathoms. The fishes with-
drawn from that depth come up more or less distended, if they possess a closed air-bladder.

1 IViegm. Arch., 1860, p. 123.

(ZOOL. CHALL. EXP. PART LVII. — 1887.) " I^H '^

XXVI

THE VOYAGE OF H.M.S. CHALLEXGER.

By the expansion of the air-bladder the oesophagus and stomach are pressed out of the
mouth and the eyes out of their sockets. Cod-fishers are therefore in the habit of
puncturing the air-bladder, in order to keep the fish alive. Every larger collection
possesses specimens showing the inverted stomach and oesophagus; and they may be
safely assumed to have been captured at some distance from the surface.

We might expect that the air-bladder of deep-sea fishes would offer special modi-
fications ; and, indeed, there is sufficient evidence that in many a special muscular
apparatus is developed for the compression or expansion of its contents, to enable the
fish to rise into a higher, or descend into a lower stratum. But, unfortunately, in all the
specimens examined by me the air-bladder was more or less ruptured and broken up,
and destroyed by subsequent decomposition. One point only seems to be clearly
made out, viz., that abyssal life has exercised no influence on the development of an air-
bladder, that is, deep-sea fishes whose nearest surface-relations possess an air-bladder,
are provided with this organ also, and vice versa. In none of the abyssal forms examined
by me have I found an open communication between the air-bladder and the oesophagus,
not even in those which are referred to the Physostomous division.

The branches of the muciferous system are dilated in many deep-sea fishes to an
extraordinary degree. Sometimes it is only the lateral line which is conspicuously wider
than in the allied surface forms (Lepidopus tenuis, many Scorpsenidse), but in mauj-
others, as in Berycidse, Macruridse, Ophidiidse, and Scopelidse, the l^ranches on the head
are enlarged into wide cavities, the walls of which are supported by high ridges of the
superficial bones. Frequently the membranes investing these cavities are very thin and
after the death of the fish liable to be destroyed, so as to leave bare the deeply sculptured
surface of the skull ; in other fishes the outer membranes collapse in consequence of the
shrinking of the mucous contents of the cavities, so that the surface of the head appears
to be extremely uneven ; whilst again in others, as in the majority of the genus
Macritrus, the integument is sufiiciently tough to maintain the natural contours of the
head. The arrangement of the cephalic branches is the same as in Teleosteous fishes
generally: the rostral l)ranches bifurcate into the frontal and infraorbital, and pass into
the scapulary branch which is the commencement of the lateral line ; and the mandi-
bulary and prgeopercular branches are likewise invariably present. All these cavities and
canals are filled with an immense quantity of mucus, which, in specimens that have not
been too long preserved in spirits, swells by immersion in water, and can be pressed out
of the apertures of the canals. These apertures may be wide slits, or more or less open,
or minute pores with or without a tubule. The physiological use of this secretion, as,
indeed, the function of the whole system, is not known. Whether it be regarded as an
excretory or as a sensory organ, it is clear that its extraordinary development in so many
deep-sea fishes must stand in relation to some one of the abyssal conditions under which
they live ; and it is very probable that some special function or functions are superadded

EEPORT ON THE DEEP-SEA FISHES. XXVll

to the original one AYiiicli the muciferous system fulfils in the ordinaxy type of surface
fishes. Considering that the majority of the localised and more highly specialised
luminous organs are situated within the area of, and stand in relation to, the muciferous
system, we may be justified in assuming that one of those additional functions is to
surround the fish with luminosity, the more so as the mucus has been actually observed
to have phosphorescent properties in newly caught specimens.

The so-called phosphorescent organs or luminous bodies have been noticed ever since
the first species of Scopelus and other pelagic genera were described ; but they were
regarded as peculiar pigment spots or modified portions of the scales. Many species of
Scopelus possess, beside the round mother-of-pearl-coloured spots, a pair of whitish gland-
like bodies on the upper side of the snout ; and it seems that Cocco was the first to
assert that these bodies have phosphorescent properties. He mentions^ these organs as
" apparecchio lucido," and one of the species possessing them he named " Nychtophus
metojMclampus." Bonaparte copied Cocco's accounts, and Valenciennes" adopted his
views as to the function of these organs. In 1864, when engaged in the systematic
arrangement of the fishes of the families Sternoptychid^, Scopelidse, and Stomiatidae, I
ascribed phosphorescent properties to all these organs, whilst from their histological
examinations Leuckart^ and Ussow* declared them, or at least part of them, to be
accessory eyes. Leydig' holds the opinion that they are " pseudo-electric " organs, which
sometimes may have the function of emitting light ; Emery" adopts the view of their
phosphorescent nature in Scopelus. As these organs occur, not only in deep-sea fishes,
but also in nocturnal pelagic forms, their function might have been expected to be readily
ascertained by actual observation ; however, so far as I am aware, this has been done
twice only, viz., by myself, when I happened to notice distinct flashes of light to issue
from a dying specimen of Scopelus floating on the surface in the British Channel ; and
by Dr. Guppy,' who examined some freshly caught specimens of the same genus.

During my examination of the Challenger fishes I found the luminous organs widelj'-
distributed over the various organs of the body, and discovered especially their presence,
in a unique modification, in a genus of Alepocephalid fishes (Xenodermichthys), as well
as in the Halosauridse, in which their relation to the muciferous system is undeniable.
Finally, Liitken^ suggested that the white terminations of the dorsal tentacle of Himanto-
lophus reinhardti may be phosphorescent during life, which undoubtedly they are.

Luminous organs are not equally distributed among the various families of deep-sea

1 Nuovi Ann. d. Sei. Nat, 1838, toiii. ii. p. 1S4.

2 Ciiv. Val., vol. xxii. pp. 443, 444, 445.

2 Ueber luutkmassliche Nebenaugeu bei eineni Fisclie, Bcricht u. d. Vcrsamml. deuisch. Naturf., 1864.

* Bull. Soc. unjh des Nat. Moscou, 1879, vol. liv. p. 79.

^ Die augenahnlichen Organe tier Fische, 1881, 8°, Bonn. >

» Mittheil. Zool. Stat. Neapel, vol. v., 1884, p. 471.
' Ann. and Mag. Nat. Hist., vol. ix., 1882, p. 202.

* Vidensk. Selsk. Skriv., vol. xi., 1878, p. 341.

XXVIU

THE VOYAGE OF H.M.S. CHALLENGEK.

fishes ; and it is a remarkable fact that they are almost entirely absent in those which
have the muciferous system most developed; thus, neither the Macruridse nor the
Ophidiidaj possess specialised luminous organs, probably because the mucus, which is so
abundantly secreted, supplies a sufficient amount of luminosity. In the Berycidse and
GadidiB we find only isolated instances, which remind us of the praeoeular or rostral
orwan of certain Scopdi. On the other hand, the Ealosauri ])ossess a wide lateral-line
system with well difi"erentiated luminous organs superimposed on it. In each of the
families of Carangidse and Alepoccphalidse one species only is provided with them. In
the Pediculati luminous organs are of common occurrence and serve as lures to attract
other fishes ; they are most common in the Sternoptychidse, Scopelidse, and Stomiatidse,
in which they have principally the function of enabling these fishes to illuminate their
surroundings, more rarely of alluring other fishes. In the MurgenidEe no luminous organs
have been found ; but in some of them the muciferous system is enlarged.

The luminous organs present many modifications as regards their seat, appearance and
structure.

' 1. In their most primitive condition they appear as innumerable minute tubercles
more or less raised above the surface of the skin, and covering the sides of the body ;
they are crowded together in transverse bands corresponding to the segments of the
muscular system. This form occurs in Echiostoma, Opostomias, Pachystomias, Photo-
nectes, Malacosteu's. I suppose that the pores scattered over the skin of some species of
Ceratias (Ceratias uranoscopus, Ceratias canmctdatiis) are apertures of follicles in which
luminous mucus is secreted.

2. Larger in size, less numerous and more projecting beyond the surface, are the
small nodules in the skin of Xenodermichthys ; they are distributed over the head as
well as the body, and follow, on the former, the muciferous ducts, whilst they are
arranged in a quincuncial fashion on the Ijody, and are wanting along the tract of the
lateral line.

3. More difierentiated are the eye-like spots, of a white colour in preserved specimens,
and red or green during life, which are arranged at regular intervals in two series on the
lower side of the body of the fish, and which occur also on the head, at the base of the
branchiostegals and on the gill-cover. Their arrangement is constant within the limits
of a species, and to judge from their external appearance they gradually pass into the
next form. They occur in numerous genera : — Gonostoma (some species), Chauliodus,
Astroncsthcs, Stoinms, Echiostoma, Opiostomias, Pachystomias, Photonectes, and
Idiacanthus.

4. Still more difierentiated are large round fiat organs of a peculiar mother-of-pearl
brightness, arranged like the former in rows on the lower side of the body and head, with
isolated ones on the sides and on the opercles, and frequently with the addition of a
.short dorsal and ventral series on the peduncle of the tail. ^ They are found in the

KEPOKT ON THE DEEP-SEA FISHES. XXIX

families Stcriioptycliidse and Scopelidse only, viz., Gonostoma (Gonostoma denudatum) ,
Argi/ro2)elecus, Sternoptyx, Polyipnus, PhoticJithya, Scopelus and Nannohrachium.

5. More or less diffuse patches of a white glandular substance of varying thickness
are found.

a. On the side of the trunk in Astronesthes.

h. On the dorsal or ventral sides of the caudal peduncle in Gonostoma and Nanno-
hrachium.

c. On or near the clavicle and more or less within the gill-cavity in SternoiJtyx,

Opostomias and Halosaurus.

d. Above the maxillary in the infraorbital region in Gonostoma and PJwtic/ithys.

e. On the top of the snout or in front of the eye in species of Melamphaes,

Melanonus and Scopelus.

f. On barbels in Linophryne, Stomias, Opostomias and Idiacanthus.

g. On fin rays in Melanocetus, Chaunax, and Himantolophus reinhardtii.

6. In this group these large glandular masses are differentiated, forming a rounded,
more or less oval mass lodged in a cavity of the infraorbital region (as in 5, d), viz., in
Anomalops, Echiostoma, Opostomias, Pachystomias, Photonectes, Malacosteus, Idia-
canthus, Astronesthes.

7. The luminous apparatus of the dorsal fin is differentiated, representing a cavity
with an aperture from which a tentacle or filament may be exserted. This form is found
in Pediculates only, such as Hunantolophus, Aegieoniclithys, some species of Ceratias,
Oneirodes and Linop>hryne.

8. The luminous organs of Halosaurus difi"er from all those enumerated, inasmuch
as they are arranged on the bodj- in a single series which is lodged on the scales of the
lateral line ; on the head they follo\\- the lower branches of the muciferous canals ; in
fact, they are situated in them. The organs have also a peculiar diamond-shape, and
nearly all lie below, but free from, the semitransparent integument of the body.

9. The cephalic organ of Ipnops, the genetic relations of which are still obscure,
althouo;h there can be no. doubt as to its function.

The disposition of all these organs will be more fully noticed in the following pages,
and a complete account of the histology of the more important forms will be given
by Professor Moseley and Dr. von Lendenfeld in the Appendices at the end of the
Report.

y- Light-producing organs are very generally distributed in the abyssal fauna, and those
parts of the depths of the ocean in which phosphorescent animals are abundant must be
sufficiently illuminated to enable such of them as are provided with well-developed eyes
to perceive objects with as much distinctness as do the pelagic forms which sport
at the surface at night, and are dependent on the light of the moon and stars and
the general phosphorescent light around them. There is no doul^t that fishes contribute

XXX

THE VOYAGE OF H.M.S. CHALLENGEE.

a considerable amouut of this luminosity of the abyssal depths ; but the various degrees
of differentiation of the luminous organs, as well as their location on very different parts
of the fish, prove that the production of light is dependent on a variety of circumstances
and subserves different purposes.

1 . Lio-ht may be produced by the luminous organ to enable its possessor to see. In fishes
which secrete merely a large quantity of luminous mucus without specially developed
oro-ans (Macrurid^e), or in which innumerable minute organs are disseminated over the
crreater part of the body, the luminosity proceeds from the general surface of the fish
whenever the animal is active, and probably ceases whilst it is asleep or at rest. But in
those fishes in which the organs are highly developed and specialised, the production of
licht is evidently subject to the will of the fish. Only thus can the luminous apparatus
be of advantage to the fish ; if the production of light were constant, or could not be
suppressed instantaneously, the fish would be a most conspicuous object and fall a ready
prey to its enemies. The high degree of development of the luminous organs on the
side of the head, in close proximity to the eye, as it is found in Anomalops and the
Stomiatidai, can be accounted for only by assuming that these fishes are able at will
to shoot rays of light in the direction which they want to explore for the purpose of
discovering their prey, or for some other object. In fact these organs are used by them
as we would use a " bulls-eye." ThQ circumstance that some of the organs are lodged
below memliranes or even in the cavities of the gills or within the mouth, cannot be
regarded as an objection to this explanation of their function, as the membranes as well
as the bones are semi-transj^arent, and would not much interfere with the eflect. No
doubt the intensity of light produced by the various organs is not the same, and it is
probably least in those least specialised : perhaps no more than the glimmer produced
by a number of minute particles of phosphorus ; but the light which issues from the large
pearly organs of the Scopelidse, the infraorbital organs of the Stomiatidse, and from the
lenticular organs of the Halosaurid^, must be intense and penetrate to a considerable
distance.

2. The luminous organs which are placed on barbels, filamentous fin-rays, or tentacles
have evidently the function of attracting other animals and of serving as lures. It is a
matter of common observation that aquatic animals are in the dark attracted by a light ;
and therefore these appendages will prove most efficient lures in the abyssal darkness,
when, with one or several bright phosphorescent spots at the end of the tentacle, they
are played about by the fish. Thus, whilst the appendages retain the original function
which they have to perform in surface fishes bke LojjJiius, Antennarms, etc., in which
they simulate a worm or other similar creature, the means by which the final end is
attamed is changed in accordance with abyssal conditions. Their luminous property
could not be of any other use to these fishes, many of which, as, for instance, the
deep-sea Pediculates, have their eye in a most rudimentary condition.

REPORT ON THE DEEP-SEA FISHES. XXxi

I am also of opinion that the highly specialised organs which are placed on the dorsal
and ventral sides of the caudal peduncle of many Scopelids and Sternoptychids, have the
function of attracting prey, and not of enabling their possessors to see. Situated at the
posterior extremity of the body, they would be in a most unfavourable position to throw
the light wdthin the area of vision by the eye. On the other hand, when we recollect the
peculiar motion of a Scopelus, which darts rapidly in short curves to' the right and left,
upwards and downwards, we can understand that these posterior organs are of great
assistance to the fish in picking up any creatures which, attracted liy the gleam
of light issuing from its tail, are lured into too near a proximity. The explanation that
these caudal organs shoot out rays of hght to frighten aw-ay a pursuer, does not seem to
me a happy idea. They are, as I assume, subject to the will of the fish, which when
pursued would simply extinguish its lantern and escape into darkness ; light w^ould not
frighten, but rather attract a pursuer.

Special organs of touch are not more generally developed in deep-sea fishes than in
the littoral fauna. As such may be considered the ventral filaments of the Ophidiidae,
the more or less detached rays of the pectoral fin of Pteroidonus, Microlene and Mixonus,
and especially of Bathypterois which possesses but rudimentary eyes, and the pectoral
filaments of which remind one of those of the Polynemidae. Indeed, the comparatively
rare occurrence of special organs of touch in deep-sea fishes may be used as evidence that
the majority depend on the sense of sight for the perception of surrounding objects, and
that therefore a la.rge amount of light must be distributed, at least locally, in depths to
which the surface light does not penetrate.

The excessively elongate fin-rays of young Trachypteridje are evidently not organs of
touch ; it is difficult to explain their use in those young fishes ; it might he imagined
that they would ])e rather disadvantageous to them by attracting other fishes of
prey, unless they afford protection by then- resemblance to delicate fronds of fucus
floating in the water or gradually settling towards the bottom. Such delicate filaments
can only be developed in fishes sojourning in water which is not subject to violent

asjitation.

In the subsequent descriptions of deep-sea fishes frequent mention is made of the
reduction in size and length of the gill-laminae. These organs appear short and shrunken ;
it is possible that they are longer during life, ending in delicate points, and shrunken only
in consequence of the action of the spirit, but the horny rods which support the plaits of
the mucous membrane are also wanting in firmness, like the parts of the skeleton, and are
much shorter than in the ordinary Teleostean type. The lamiuas are also reduced in
number, and the gill does not possess the same extent of respiratory surface, so that
the intensity of ttie respiratory process seems to be more diminished than in surface
fishes. We can hardly doubt that the sojourn in the low temperature of the abyssal
depths must have some efiect upon circulation, respiration, assimilation of food

xxxii THE VOYAGE OF H.M.S. CHALLENGEE.

and secretion ; but we cannot hazard a conjecture as to the manner and degree in which
those physiological functions may differ from those of surface fishes.

I may here also shortly refer to a subject in regard to which very few facts are
known, and which therefore offers wide scope for speculation. It is the fact that the
spawn of some deep-sea fishes (as for instance Polyjjrion cernium), is developed at the
surface, whilst mature individuals of the species reside at more or less considerable
depths. It is not probable that these fishes rise to the surface at the season of
propagation ;■ we may rather suppose that the spawn is deposited at a depth of several
hundred fathoms and gradually rises to the surface, the young fish, after a short
pelagic surface existence, returning to the depths inhabited by their progenitors.
This, however, is certainly not the case with all deep-sea fishes ; of many the spawn will
not only be deposited at the bottom of the ocean, l)ut also remain there throughout
the period of its development. But when we consider the immense diff"erenee of the
conditions under which the development of the ova of these two kinds of fishes pro-
ceeds— the one under the accelerating influences of light, warmth, and a constant
supply of oxygen, the other under the retarding conditions of darkness, cold, and a
minimum amount of oxygen — we cannot help thinking that the one series supplies the
deep sea with the forms which retain the organisation of the surface fishes, whilst
the other develops into those degraded forms, of which the families Ophidiidfe and
Mursenidse offer the most striking examples.

The colours of deep-sea fishes are extremely simple, their bodies being either black,
pink, or silvery ; however, some of the fishes which now are black are described as
having been of a bluish colour when they were brought to the surface. In a few only
are some filaments or the fin-rays of a bright scarlet colour ; black spots on the fins
or dark cross-bars on the body are of very rare occuiTcnce. An extremely common,
almost general characteristic of deep-sea fishes is the black coloration of some of the
body-cavities ; this is limited to the pharynx in many of the fishes which live about
the 100-fjithoms limit, but the colour is more intense, and spread all over the oral,
branchial, and peritoneal cavities in strictly typical deep-sea forms. The highly
specialised luminous organs on the head of the Stomiaticte are green or pi)ik during
life, whilst they fade into white after the immersion of the fishes in spirit. Among the
black- coloured deep-sea fishes albinos are not scarce.

REPORT ON THE DEEP-SEA FISHES. xxxiii

VERTICAL AND HORIZONTAL DISTRIBUTION OF DEEP-SEA FISHES.

Before the voyage of the Challenger scarcely thirty deei^-sea fishes were known ; this
number is now increased to about 370, if we include a few species which are, in fact,
surface fishes, but descend occasionally or regularly to or even beyond the 100-fathoms
limit. In a table appended to these introductory remarks, I have endeavoured to show
in a graphic manner the bathymetrical range of each species, so far as it has been
ascertained at present. Unfortunately, some uncertainty prevails as regards the depth
at which certain specimens were obtained, I formerly assumed that the fishes of the
open sea were living either near to the surface or at the bottom, but I think now that
Mr. Murray is right in supposing that certain fishes live habitually in intermediate
strata, without ever coming to the surface or descending to the bottom.' The function
of the pneumatic apparatus with which many deep-sea fishes are provided is to regulate
their specific gravity, so that a fish is able to maintain its position at a certain
depth, which would vary only within certain limits, comparable to those which we
observe in surface fishes. As the mouth of the dredges or trawls used by the
Challenger was open during their descent or ascent, it is within the limits of proba-
bility that sometimes fishes were accidentally enclosed whilst the apparatus was
traversing the strata intermediate Ijetween the surface and bottom. And this has
actually happened more than once ; for it is quite certain that common surface fishes,
like Sternoptyx and Astronesthes, never ranged to the depth of 2500 fathoms, the
depth to which the dredge had descended on the occasion of the capture of these
specimens. On the other hand, many of the fishes obtained by the Challenger ofi"er
suflicient evidence, from their own organisation, that they live at the bottom, and are
unable to maintain themselves suspended in the water ; and, consequently, that they
actually were obtained at the depth to which the dredge descended. Besides, the
statements of the depths of the Challenger fishes have been confirmed in many instances
by the observations made during the more recent deep-sea explorations.

However, it may be assumed that of those mid-watei' fishes, as the forms may be
called which inhabit intermediate strata, comparatively much fewer specimens are
captured than of the bottom fishes. It must be of rare occurrence that fishes accidentally
enter the narrow mouth of the dredge whilst it is passing to the bottom or to the surface,
and it is more likely to happen when the larger trawl is used. But such free-swimming
fishes are much more agile in their movements, and escape more easilj'' on perceiving the

1 The habit of some fishes of living at a distance from the surface ami bottom is a fact which has been known for
a long time among fresh-water fishes. Salmo lacustrii, of the Lake of Constance, has received its vernacular name
from this habit ; it is called " Schwebe-forelle," that is, the trout which is suspended in mid-water.

(ZOOL. CHALL. EXP. — PART LVII. — 1887.) Lll 6

XXXIV

THE VOYAGE OF H.M.S. CHALLENGEE.

approach of the dredge than bottom fishes, which are generally of a more sluggish
nature, and which, seeking safety by burying themselves in the ooze, would be
readily enclosed in the dredge.

So far as the observations go at present, no distinct bathymetrical zones, characterised
by peculiar forms, can be defined. As the transition from the organisation of the typical
surface fish to that of the most highly specialised deep-sea form is gradual, so the passage
from the Uttoral to the abyssal fauna is continuous and not marked by a sudden change.
The limits between the two faunas are still more obscured by the remarkable manner in
which they overlap each other owing to the wide bathymetrical range of certain species
of either fauna. I need only mention such common littoral forms as Lophius piscatorius,
Meiiuccius vulgaris, and Pleuronectes cynoglossus, which descend to depths of from
300 to 700 fathoms, thus living in the same areas which are inhabited by the most
highly specialised abyssal forms like Chiasmodus, Trachypterus, and Alepocephalus.
Also the temperature of the water clearly interferes mth a uniform bathymetrical dis-
tribution of fishes, as many species, which in low latitudes are found at considerable depths,
often ascend into the cold surface strata of high latitudes.' Further, nocturnal pelagic
surface fishes seek, during the day-time, the darkness of greater depths. The instances of
the wide bathymetrical range of deep-sea species are numerous : some may range from
a depth of some 300 fathoms down to one of 2000 fathoms ; or, in other words, a fish
which has once attained in its organisation to that modification hy which it is enabled to
exist under the pressure of half a ton, can easily accommodate itself to one of two tons or
more.

But if there are serious obstacles to a division of the deep-sea fish-fauna into vertical
zones characterised by the presence of peculiar forms, there are less objections to an
attempt to show to what limits the families of fishes descend which are represented in
the deep-sea by surface-forms or their modifications. As far as our present knowledge
goes, we find —

1. That at a depth of 400 fathoms the Gobiidse, Trachinidse (with the exception of
Bathydraco), Blenniidae, Percidee, Scorpaenidae, Tricliiuriche, Cyttidse, Cataphracti,
Bathythrissidse cease to exist.

2. At a depth of 500 fathoms two important types, viz., the Sharks and Eays, and
the Flat-fishes cease to flourish, only one isolated example of each descending beyond that
bmit.

3. At 700 fathoms several other families, which are chai'acteristic forms of the littoral
fauna of the cold and temperate zones disappear, viz., the Cottidee, Discoboli, and
Lycodidse (with one exception); there is also no evidence of the Trachypteridse and
Myxine extending beyond this depth.

4 The depth of 1200 fathoms seems to be the limit of the Holocephali.

1 This fact -was first expressed in Introduction to the Study of Fishes, p. 30.5.

REPORT ON THE DEEP-SEA FISHES. XXXV

5. Beyond 2000 fatlioms neither Gadidse nor Salmonidse nor Notacantlii have been
found.

6. The families which descend to the greatest depth at which fishes have been
obtained, viz., 2900 fathoms, are Berycidse, Pediculati, Ophidiidse, Macruridse, Sternopty-
chidge, Scopehdae, Stomiatidte, Murseuidse ; also two fomilies which have no representa-
tives in the surface-fauna, viz., the Alepocephalidse and Halosauridje, extend to the same
enormous depth ; and there is no reason why all those deep-sea forms, wliich are known
to live at a depth of nearly 3000 fathoms, should not occur in the greatest abyss of the
ocean.

The abundance and variety of fish life decreases with the depth, as is obvious from
the following table, which expresses our present knowledge of the subject. There have
been found

between 100- 300 fathoms 232 species.

300- 500 „ 142

500- 700 „ 76

700-1500 „ 56

1500-2000 ,, 24 „

2000-2900 „ 23

Of those found between 100 and 300 fathoms 108 also occur above the 100-fathoms
limit.

This decrease in the number of species, as shown in this table, is no doubt partly
owing to the difficulty of capturing fishes at great depths, a difficulty which increases in
proportion to the depth at which the dredge is worked. But it must also be regarded as
evidence of the actually diminished variety of fishes. Fishes may Ije, and no doubt are,
locally abundant at the bottom of the ocean ; but this abundance is probably one of
individuals rather than of distinct forms. We may safely assume, that as the majority
of deep-sea fishes are modifications and derivatives of surface forms, they are fewer in
number than the latter, especially when we consider that the physical conditions of the
abyss are of a very uniform character, and therefore cannot have given rise to the
development of numerous specific and generic forms.

This uniformity of the physical character of the lowermost strata of the ocean is also
the cause of the almost unlimited horizontal distribution of deep-sea fishes. Pelagic
surface-fishes have already a wide range, but are more or less influenced in their
distribution by climatic conditions. Deep-sea fishes are no longer subject to this cause
of limitation when they have reached a deptli of 500 fathoms, where the temperature of
the water is as low as 40° F., and perfectly independent of that of the surface water.
Therefore, the instances already known of the same genera, and even of the same
species occurring in the depths of the eastern and western, northern and southern

xxxvi THE VOYAGE OF H.M.S. CHALLENGER.

hemispheres are numerous, and will be still more increased by future investigations. A
certain number of the species are no doubt more localised ; those will be chiefly such as
have been derived, and are not yet far removed in their organization, from littoral forms.
Others, which may be supposed to have been derived from pelagic surface fish, may have
been as widely distributed, almost from the beginning of their existence, as their ancestors.
At present, however, our knowledge of the actual distribution of deep-sea fishes is much
too imperfect to be used as a safe basis for further generalisations.

REPORT ON THE DEEP-SEA FISHES. xxxvii

THE CONSTITUTION OF THE FISH-FAUNA OF THE DEEP SEA.

If, as has been done in the present Eeport, all species which hitherto have been found
at a depth of 100 fathoms are included in the deep-sea fauna, so great an admixture
of surface forms is admitted, that the characteristic features of abyssal fauna are
obscured. We obtain a more correct idea of its constitution if we take into consideration
only such forms as have been found from 300 fathoms downwards ; eliminating from
the total number of 385 species enumerated in this Report all which do not descend to
300 fathoms, 155 in number. This leaves 230 true abyssal forms.

Of this number the

Chondropterygians

furnish 8

species

or 31

Holocephah

))

2

>)

1

Acanthopterygians

jj

64

>>

26

Berycidae

• S)

24

>>

101

Pediculati

)J

7

))

Trachypteridse

JJ

7

)>

Scorpsenidse

J)

5

)>

Discoboli

J>

5

>j

Percidse

)J

4

))

Trichiuridse

))

4

J)

Cottidse

»)

3

>>

Cataphracti

>)

2

j>

Cyttidas

)>

1

))

Trachinidse

J)

1

))

Lophotidse

)5

1

>)

Anacanthini

))

91

))

40

Lycodidfe

>)

13

5)

Gadidse

5)

19

)5

9

Ophidiidae

))

20

))

9

Macruridse

))

37

>1

16

Pleuronectidse

»

4

))

Physostomi

3J

63

)J

26

Scopelidae

5»

17

))

Mursenidse

J)

13

JJ

Stomiatid^

)J

10

it

Alepocephalidse

)J

9

>J

XXXVIII

THE VOYAGE OF H.M.S. CHALLENGER.

Halosauridse
SternoptyehiclEe
Salmonidge
Notacanthi
Bathythrissidae
Cyclostomi

furnish 5 species.

4
2
2
1

9,

or 1 per cent.

As regards the abundance of individuals the Macruridse seem to surpass all the other
forms ; then follow the Ophidiidse and Gadidfe. Scopelidge and Stomiatidse are likewise
numerous, much more so than the Berycidse, although these latter are represented by a
greater number of species.

xl

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distnhution

0-100 100-300

300-500 500-700 '

— . — ^ 1

700-1000

Sharks—

i

Scyllium canescens,

Pristiurus melatioatomus,

Spinax spinax,

Spinaie granulosa,

—

•

Centrophorus foHaceiiS,

^—

Cenlrophorus cmloUpis,

Ceivtrophorm squamulosus.

.

CenlroscylHumfabricii,

Centroscyllium gramilatum, .

•

^^"

Lxmargjis borcalis, . . . • •

Eays—

Baja isotrachys,

•

—

Baja circularis,

Raja radiata, .

Raja hyperborea,

Rajaplutonia, .
Raja batis,

Raja vomer,
Rajafullanica,

^—

Raja nidrosiensis,

•

Urolophus kaianus,

—

HOLOCEPHALA—

Chimara monstrosa, .....
Chirruera affinis, .....

ACANTHOPTERYGJ 1 —

Percidse —

Anthias megalepis,

—

.

CerUropristis pUurospilus,

—

•

•

.

.

Sambrops chilodipteroides.

•

--

Aoropoma philippiiieiise,

■

■-

.

.

Propoma roseum.

—

•

1

2
3
4
5
6
7
8
9
10

11
12
13
14
15
16
17
18
19
20

21
22

23
24
25
26
27

REPOET ON THE DEEP-SEA FISHES.

xli

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

\ ■ ■ ■ ■

(ZOOL. CHAT.Ti. EXP. — PART LVII. — 1887.)

LU/

xlii

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

jMalacicMhys griscus,
Synagrops japonicus,
Polyprion cemium,

Scorpsenidffl —

Scorpxna dactyloptera,
Scorpsstia kuhlii (see Lowe),
Sebastes marinus,
Setastes vimparus,
Sebastes macrochir,
Sebastes hexcmema,
Sebastes oculatus,
Setarches fidjUnsis,
Setarches parmatus,
Setarches guntlieri,
Bathysebastes albescens,
Lioscorpiiis longiceps, .

Beryeidse —
Hoploslethiis iiuditerraiKum,
Tracliichthys australis,
Trachichlhys jacksoniensis,
Trachichthys elongatus,
Trachichthys ferrumdezianus,
Trachichthys traillii, ,
Trachichthys inacleayi,
Trachichthys intermedins,
TrachicMhys darwinii,
Anoplogaster cornutus,
Caulolepis langidens, .
Melamphaes microps, .
Melamphaes typhlops .
Melampliaes megalops,
MelampJiaes crassiceps,

0-100 100-300 300-500

500-700 700-1000

28
29
30

31

32
33
34
35
36
37
38
39
40
41
42
43

44
45
46
47
48
49
50
51
52
53
54
55
56
57
58

REPORT ON THE DEEP-SEA FISHES.

xliii

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

1

xliv

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distrihtition

0-100

100-200

300-500

500-700

700-1000

Melamphaes mizoUpis,
Melamphaes roiustus,
Melamphaes leanii,
ifelarnphaes suborbitalis,
Malacosarcus mncrostoma,
Slepkanoberyx inonx,
Beryx decadaciyliis,
Bcnjx spUndens,
Polymixia noUlis,
Poromitra capita,
Myripristis Icaianus,

Trichiuridje —
Nealotus tripes,
Aphanopus carho,
Nesiarchus nasiUtis,
Lepidopus caudatus,
Lepidop^LS tenuis,
Lepidopus elongatus,
Trichiurus leplurus,
Euoxymetopon tmniatus,
Euoxymetopon poeyi,
Thyrsites pretiosus,
Thyrsites prometTieus,
Gempylus serpeiis,

Carangidse —
Anomalops palpebratus,

Cyttidae —
Cyttus dbbreviattts,
Antigonia capros,

Coryphaenidae —
Direlmus argenteus,
Diretmus aureus,
Schcdophilus medusophagus,

-(?)

-(?)
-(?)

-(?)
-(?)

--(?)

-(?)

REPORT ON THE DEEP-SEA FISHES.

xlv

of Species, Genera, and Families.

1000-1600

1500-2000

2000-2900

xlvi

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

0-100

100-300

300-500

600-700

700-1000

SchedopMlus lockingtmii, ....
Sckedophiltcs enigmaticus, ....

(0

_. nx

•

87
88

y:j

Trachinidse —

Bathydraco antarcti&iis, ....

•

89

Aphrilis gobio, . .

90

Aca7ithaphritis grmviisguainis,

•

91

Champsodon varax, .....

92 ■

Uranoscopus Jcaianus, .....

93

Notothenia mizops, .....

..-

—

93a

Pediculati—

Lophius pixr/iimius, .....
Lophitis naresii, .....

94
95

Himantolophus groenlandieus,

Himantolophus reinhardli, ....
Aegmonichthys appelii, ....
Ceratias bispinosus, .....

-----H^

. n>

96

— \i)

(7\

97

98
99

Ceratias holbolli, .....

{i\

— (U

100

Ceratias uranoscopus, .....

,

1

Ceratias carunetdatus, ....

,

2

Oneirodes esehrichtii, .....

_.

— (?)

3

Mcla7iocetus johiisonii, ..'..,

4

Melanocetus murrayi, .....

5

Linopkryne lucifer, .....

,

(?)

6

C%aM!Ma; ^>irfM«, .....

ffalieutsea senticosa, .....

7

8

DibrancJius ailanticus.

.

^.^

9

Cottidae—

Coltunculas microps, .....

1

10

Cottunculiis thomsonii, ....
Cottus bathybius, ....
Ceiitridermichthys wieinatus, ....

•

•

11

12

/ceZus limnatiis, ....

13

Triglops pingelii, • ■ . . .

14

1 1

•

15

REPORT ON THE DEEP-SEA FISHES.

xlvii

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

87
88

89
90
91
92
93
93a

94
95
96
97
98
99
00

1

2

3

4

5

6

7

8

9

10
11
12
13
14
15

.

•

xlviii

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

0-100

100-300

300-500

500-700

700-1000

Trigla leptaamthus, .....

•

Lepidotrigla spiloptera, ....

•

Cataphracti — ■
Peristetlvus miniatuvi, .....
Peristethus molitccense, ....

Peristethus murrayi, .....

Peristethus liorhynehus, ....

Peristethus micrcmema, . . . .

—

Agonus decagonus, .....
Discoboli —

Cyclopterus spinosus, .....

.

.

Liparisfahrioii, .....

.

Liparis mieropus, .....

Liparis gelatinosus, .....
Paraliparis bathybius, ....

,

.

Paraliparis Uparinus, ....

.

.

,

Paraliparis membranaceus, ....

•

•

Gobiidse —

Callimymm kaiamia, .....

■^

. .

CalUonymus calaurspomus, ....
Blenniidie —

Anarrhichas minor, ....
Anarrhiehas latifrons, ....
Blenniops ascanii, .....

Trachypterida —

•

.

Trachypterus, ......

Stylophortis, ......

(?)

.

Begalecas, ......

Lophotidffi—

.

Lophotcs, ......

•

1

REPORT ON THE DEEP-SEA FISHES.

xlix

of Species, Genera, and Families.

1000-1500

1500-2000 ' 1 2000-2900

(ZOOL. CHALL. EXP. — PART LVII. — 1887.)

mg

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

0-100

100-300

300-500

500-700

700-1000

Phartngoonathi—
Eeliastes roseus, .....

Anaoanthini —
Lycodidse —

•

•

Lycodes reticulatus,
Lycodes frigidus,
Lycodes pallidum,
Lycodes seminudus,
Lycodes mursena,
Lycodes sarsii,
Lycodes vcrrilli,
Lycodes paxillus,
Lycodes paxilloides,
I/ycodonus mirabilis,
Chjitinelis i>iridis

•

1

1

1

•

1

-

•

•

•

•

MelttThostiOTnct Qelcttiuosum

Gadidfe —

•

Gadus poutassou,
Gadus argentcus,
Gadus minutus (see Risso),
Mora incditerranea.

•

Halargyreus johnsmiii,
Melanomts gracilis,
Mcrluccius vulgaris, .

Hypsiconictcs gobioides,
Lotclla marginata,

...

Uraleptus maraldi (see Risso),
Physiculus dalwigkii,

•

Physieulus Tcaupi,
Physiculus peregrinus,
Phycis blennioides.

—

—

1

141

42
43
44
45
46
47
48
49
50
51
62
53
54

55
56
57
58
59
60
61
62
63
64
65
66
67
68
69

REPORT ON THE DEEP-SEA FISHES.

li

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

141

42
43

H

45

46
47
48
49
50
51
52
53
54

55
56
57
58
59
60
61

62
63
64
65
66
67
68
69

lii

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

Phyds chesteri,
Phycis regius, .
Phyds americanus,
Phycis tenuis, .
Lxmouema iarhatMlum,
Ealaporphyrus guentheri,
HalaporphyrVjS lepidion,
Haloporphyrus cqucs, .
ffaloporphyrus inoeimse,
ffaloporphynis ensiferus,
Antimora rostrata,
Antimora viola,
Molva molva, .
Molva abyssorum.
Onus macropJithalmiis,
Onus carpenteri,
0}ms reinhardli.
Onus scptentrionalis,
Onus ensis,
Onus cvmhritis,
Brosmius hrosmc,
Chiasmodus niger,

OphidiidiE —
Barathrodemus inanatiims,
Neobythites grandis,
Neohythites niacrops, .
Neohythiles ocellatus, . .
Neobythites gillii,
Calsetyx messieri,
Pteridium atrum,
Pteroidonus quinquarius,
Dicrolene intronigra, .
Mixonus laticeps,

0-100 100-300 300-500

500-700

700-1000

170

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

89
90
91

92
93
94
95
96
97
98
99
200
1

REPORT ON THE DEEP-SEA FISHES.

liii

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

70
71
72
73

74
75
76
77
78
79

'1

82
83
84
85
86
87
88
89
90

Q1

92
93
94
95

96
97
98
99

!00

1

Uv

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

£cUhyonus compresms,
Bathyomus tasnia,
Bathyomis catena,
Porogadus gracilis,
Porogadus miles,
Porogadus rostratus, .
Nematonus pectoralis, .
ZHplacantTiopoma brachysoma,
Acanthonus armalus, .
Typhlonus nas^is,
Aphyonus gelatinosus,
Ophidium murxnolepis,
Rhodichthys regiiia,

Macruridse —
Macrurus parallelus, .
Macruriis japoniciis, .
Macrurus australis,
Macrunis ccelorhynch'us,
Macrurus carminatus,
Macrurus /asciaius,
Macrurus fabricii,
Macrurus rudis,
Macrurus nasutus,
Macrurus serrulaiiis,
Macrurus selerorhynclms,
Macrurus sequalis,
Macrurus bairdii,
Macrurus goodii,
Macrurus hololrachys,
Macrurus asper,
Macrurus carinaius,
Macrunis rupestris,
Macrurus altipinnis.

0-100 100-300 300-500 500-700

700-1000

202
3
4
5

10
11
12
13
14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

EEPORT ON THE DEEP-SEA FISHES.

Iv

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

202
3

4
5
6

7

8
9

10
11
12
13

U
15

16

17

18

19

20

21

22

. .

23

24

25
26

27

28
29

30
31

32

33

1

Ivi

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Dislnhution

MacTurus longibarhis,
Maci-urus italicus,
MaCTUTUs filicavda,
Macmrus microlepis,
Macrurus viUosus,
Macmrus crassiceps,
Macrurus leptolepis,
Macrurus simulus,
Macrurus femMndeziarms,
Macrurus liocephaZus,
Majcrurus murrayi,
Macrurus derUiculaius,
Macrurus Isevis,
Macrurus macrochir,
Macrurus sulcatum,
Macrurus amiaius,
Macrurus affinis,
Macrurus longijilis,
Trachyrhynchus trachyrhymhus,
Trachyrhynchus longiroslrw,
Trachyrhynchus murrayi,
Balhygadus cottoides, .
Bathygadus multifilis,
Balhygadus cavemosus,
Bathygadus macrops, .
Bathygadus longijilis,
Macruronus novx-zelandiie,

Ateleopodidae —
Ateleopus japonicus, .

Pleuronectidae —

Eippoglossus pinguis, .
Hippoglossoides platessoidcs,
Poedlopsctia colorata, .

0-100 100-300 300-500

500-700 700-1000

-(?)

EEPORT ON THE DEEP-SEA FISHES.

Ivii

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

(ZOOL. CHALL. EXP. PART LVII. 1887.)

LU/i

Iviii

THE VOYAGE OF H.M.S. CHALLENGEE.

Vertical Range of Distribution

0-100 100-300 300-500 500-700

700-1000

AnticUJiarus pohjspilus,
Samaris maculatus,
Lepidopsetta maculata,
Pseudorhomius Jiectoris,
Pseudorhombus hoops, .
Psevdorhomius oblongus,
Pseudorhombus ocellalus,
Monolene sessilkauda,
CitJiaricMhys arctifrons,
Citharichthys unicornis,
Pleuronectes heanii,
Pleuronedes cynoglossus, ■
Nematops microstoma,
Solea TcaiaiM, .
Aphoristia nebulosa, .

Phtsostomi —
Steruoptychidte —
ArgyropcUcus hemigymnus,
Argyropelecus olfersii,
Slernoptyx diaphana, .
Polyipnus spinosus,
Gonostoma denudatum,
Gorwstoma elongalum,
Gonostoma gracile,
Gonostoma microdon, .
Photichthys argenteus,
Chauliodus sloanii,

Scopelidte —
Saurus kaianvs,
Harpodon microchir, .
Bathysaurus fcrox,
Balhysaurus agassizii,
Bathysaurus mollis,

■(?)

REPORT ON THE DEEP-SEA FISHES.

lix

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

1

Ix

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

0-100

100-300

300-500

500-700

700-1000

Tl It. J • 7.. 'J??."-

Bathypterois longijilis,

Bathypterois longipes, .

•

Bathypterois longicavda,

Bathypterois gicadrijilis,

Ipnops murrayi,

Chlorophthalmus agassizii,

Chlorophthalmus productiis,

Chlorophdudmus nigripinnis,

Chlorophthahmcs gracilis,

Scopelus macrolcpidotus,

Scopeliis gladalis,
Scopelus engraulis,

•

Scopelus dumerilii.

Nannobrachium nigrum,

Odontostomus hyalinus.

Omosudis lowii,

-^—

Plaavodus ferox

Stomiatidse —

^stTonesthes niaer

Stomias hoa, .
Stomias afflrds,

Stomias ferox,
Echiostoma lariat um,
Opostomias micripnus.

Pachystomias nviarodon,

Photonectes alhipinnis.

ft)

Malacosteus niger.

(?)

Malacosteus indicus, .

BatTwphihis nigerrimus.

(?)

.

Idiacanthus fasciola, .

--(?)

Idiacanthus ferox.

Salnioiiidce —

Argentina silus, ...

.

_l

295

96

97

98

99

300

1

2

3

i

5

6

7

8

9

10

11

12
13
14
15
16
17
18
19
20
21
22
23
24

25

REPORT ON THE DEEP-SEA FISHES.

Ixi

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

Ixii

THE VOYAGE OF H.M.S. CHALLENGER.

Vertical Range of Distribution

Argentina lioglossa,
Argentina elongata,
Sathylagits atlaviicus,
Bathylagus atUarcticus,

Bathythrissidse—
Bathythrissa dorsalis,

Alepocephalido;^
Alepocephalus roslraius,
Ahpoccphalus agassizii,
Alepocephalits productus,
Alepocepltalus hairdii,
Alepocephalus niger, .
Bathytrodes macrolepis,
Balhytroctes micralepis,
Bathytroctes rostratus,
Plalylroctes apus,
Xenodermichikys nodulosus,

Halosauridffl —
Saloaaurus owenii,

Ealosaurua macrochir,

Halosaurus mediorostris,

Halosaurus rostratus, .

Halosaurus affinis,

Notacanthi —
Notacanthics scxpim's, .

Notacanthus nasus,

Notacaiithus phasganorus,

Notacanthus honapartii,

Notacanth us rissoanus,

Mui-itnida; —
Cougromuraina guttulata,
Sijiienchelys parasiticus,
Neltastoma melanurum.

0-100 100-300 300-500 500-700 700-1000

-(?)

326
27
28
29

30

31
32
33
34

35
36
37
38
39
40

41
42

43
44
45

46
47
48
49
50

51
52
53

REPORT ON THE DEEP-SEA FISHES.

Ixiii

of Species, Genera, and Families.

1000-1500

1500-2000

2000-2900

(?)

^

Ixiv

THE VOYAGE OF H.M.S. CHALLENGEE.

Vertical Range of Distribution ■

0-100

100-300

300-500

500-700

700-1000

Nettastoma parviceps,
Nettastoina procerum,
Synaphobranchiis pinnatus,

Synaphdbramlms bathybius, .

•

Synaphobraruohus brcvidorsaU%
Saccopharynx ampullaceus.

Saccopharynx pelecanoides,
Saccopharynx bairdii,
NemicMhys scolopaeea,
Nemichtkys infans,
Cyema atrum,

•

i

■

•

Pleotognathi—

Triacanthodes anomalus, ....

.

.

Manamntkus tesstUatus, ....

•

•

.

Cyclostomata —

Myxine glutinosa, .....

■

•

•

354

55
56
57
58
59
60
61
62
63
64

65
66

67
368

KEPOllT ON THE DEEP-SEA FISHES.

Ixv

of Species, Genera, and Families.

1000-1500

1500-2000

354
55
56
57

58

59

2000-2900

60
61
62
63
64

65

67
S68

(ZOOr,. CHALL. EXP. — PART [.Vlt.- -1 887.)

LU »■

DESCRIPTION OF SPECIES.

PLAGIOSTOMATA.

SELACHOIDEI— SHARKS.
Family Scylliid.e.

Scyllium, M. and H.

The species of " Dog-fishes " hitherto known are strictly littoral, and, besides, have
but a limited distribution. It is therefore a matter of some interest to find a species
living at so great a depth as 400 fathoms, although there is nothing in its organisation
which would have led us to suspect its bathybial habits.

Sci/Uium canescens (PI. I. fig. A).

Sajllium canescens, Giinth., Ann. and Mag. Nat. Hist., ser. 5, vol. ii. p. 18, 1878.

The nasal valves are separate from each other, the distance between them being less
than the length of a nasal opening ; each is provided with a cirrus. Lengtli of the
prgeoral portion of the snout much less than its width, or than the width of the mouth.
Labial fold very short. Teeth very small, those of the lower jaw tricuspid, the cusps
being subequal in length. Ventral fin with the posterior margin very oblique. The
posterior dorsal slightly longer than the anterior. The anal terminates below the middle
of the second dorsal, its base being longer than that of the latter fin, and equal to its
distance from the caudal. The whole body rough from small spines. Uniform greyish ;
all the fins, except the caudal, tipped with white behind.

Habitat. — South-western coast of South America, Station 310 ; depth, 400 fathoms.
One specimen, 11 inches long (young female).

(ZOOL. CHALL. EXP. PART LVII. 1886.) LU 1

5

2 , THE VOYAGE OF H.M.S. CHALLENGER.

Pristiurus, Bonaparte.
Fristiurus melanostomus, Rafinesque.

CoUett' records the capture of this littoral species near Tromso, at a depth of
250 fathoms.

Family Notidanid^.
Chlamydoselache, Garman.
Chlamydoselaci,e anguinea (Pis. LXIV., LXV.).

Chlamydoselachus anguineus, Garman, Bull. Mus. Comp. Zool., vol. xii. No. 1, 1885.

I am indebted to M. S. Tegima and A. Sanders, Esq., for three well-preserved examples
of this shark, which hitherto was known from a single specimen onl)^ a female without
intestines, and with a mutilated tail. Our specimens were caught in deep water in Yeddo
Bay, opposite Tokio. Two are males, of which the larger is 4 feet and 10 inches
long, the tail measuring 2 feet ; the third is a female, which had been eviscerated by
the fishermen, from whom it was bought. I am alilc to supplement Mr. Garman 's account
by some remarks on the male claspers and other organs.

The membranous margin of the ventral fin of the male is attached to the outer
and upper side of the clasper, leaving only the terminal third of the latter free, as is the
case in the Notidanidse generally, whilst in other sharks the fin and the clasper are separated
by a more or less deep notch (PI. LXIV. fig. C).

The skeleton of the clasper is extremely simple (PI. LXIV. fig. D, D'). The
principal cartilaginous rod (a) is attached to the basale (h) of the pelvic limb by three
rudimentary and one larger intermediate cartilages {a'). The ventral side of its terminal
third is longitudinally concave, forming a half-canal which in its middle is bridged over
by a lobe-like expansion of the cartilage (/). A long calcified piece {t, t') with sharp
cutting edge is movably attached to each side of the end of the semicanal. These two
movable appendages can be approached to each other so as to complete or close the canal.

The structure is therefore very similar to that of Acanthias as figured by Gegenbaur.^
The cartilaginous ray (?■) nearest to the clasper (or pterygopodium, Petri) is much elongate,
tapering, simple, occupying a position at about equal distance from the clasper and the
ray next above it. This latter {>•'), the penultimate of the series, is also elongate, and
consists of two pieces subequal in length, with a minute terminal piece, the rudimentary
condition of which leads me to suppose that it will not be found to be constant. The
third ray (r") is somewhat shorter than the second, consisting of two pieces, like the second,
but without the rudimentary terminal. The following rays become successively shorter,
are composed of three pieces, and arranged closely side by side, as in the female fish
figured by Garman.

> Nyt Mag.f. Natuniid, xviii., 1884, p. 117. - Jenaische Zeitschr., v., Taf. xvi. figs. 15-17.

REPORT ON THE DEEP-SEA FISHES. 3

The teeth (PI. LXIV. figs. A and B) are arranged with great reguLirity in series crossing
the jaws obliquely. Each anterior series consists of six, and the posterior ones of five teeth,
to which generally from one to three in an immature state of development are added. The
series are separated from each other by a toothless space which becomes narrower between
the posterior series ; the latter are composed of much smaller and rudimentary teeth ;
in fact, the last two or three series are almost confluent, rendering the number of series
somewhat uncertain, so that it may be given as twelve or thirteen on each side of the
upper jaw. There is a broad toothless space in the middle of the upper jaw, and the
two or three foremost series are bent outwards beyond the margin of the jaw, so that the
two or three foremost teeth are entirely outside the buccal cavity. The lower jaw is
armed with one unpaired additional series on the symphysis ; in other respects, with
regard to position, arrangement and number, the teeth of the lower jaw do not differ
from those of the upper. Each tooth consists of an oblong base bearing on its
anterior portion three long, divergent, pointed, spine-like cusps, with a pair of much
smaller ones between. These cusps are directed backwards over the base of the tooth.
On its lower side the base has anteriorly a pair of shallow grooves [g] to receive two
short pointed processes (/j).in which the base of the preceding tooth terminates ; by these
processes fitting into the grooves of the succeeding tooth, the union of the links of the
dental chain is effected. In the rudimentary teeth of the posterior series the base of each
tooth is veiy much abbreviated ; the cusps also are much shorter and have a more erect
position. In the teeth of the series which may be considered the last, the outer cusp
is even entirely lost or quite rudimentary ; in fact, these minute teeth differ very little
from the enlarged papillfe of the surrounding skin.

The stomach is an extremely long cylindrical sac with thin walls ; the short and
narrow intestine, after having made a short and incomplete convolution, passes into the
dilated portion which contains the spiral valve. This portion (PI. LXV. figs. 5 and 6) has
extremely strong muscular walls, from 3 to 4 mm. thick. The spiral valve makes thirty-
five gyi-ations, this part of the intestine being six and a half inches long. A globular
glandular body (fig. 3, gl) of the size of a large pea lies dorsad of the cloaca, into wliich
it discharges its secretion by a short duct.

The liver consists of two extremely long lobes which reach backwards to the end of
the abdominal cavity, and anteriorly receive the gall-bladder between them ; this organ
is of moderate size.

The testicles are narrow elongate bodies of nearly equal size, about 5 inches long
and half an inch broad at the broadest part. Although our specimens seem to be sexually
mature, I am uncertain whether they were captured during the season of propagation.
The testicles reach close to the upper end of the abdominal cavity. In one of the males
the arrangement of the urogenital organs and ducts, as well as of the external openings,
is perfectly symmetrical and normal (fig. 1), whilst in the other the left side shows a

4 THE VOYAGE OF H.M.S. CHALLENGER.

much more developed condition than the right (figs. 2 and 3). In the latter specimen
the left vas deferens (vd) is much wider than the right (vd'), and provided in its
interior with low, circular, closely-set septa (fig. 4), of which only faint traces can be
seen in the right duct. They are, however, limited to the lower 3 or 4 inches of
the duct. The leit vas deferens opens into the urinary bladder (fig. 3, u), if a bottle-
shaped dUatation which terminates externally in a single small conical papilla (uf) may
be so called. The right vas deferens opens by a slit at the side of the papilla directly
into the cloaca (figs. 2 and 3, ug). There is also in this specimen only one porus
abdominalis in the median line (or very slightly to the left of it) immediately behind
the cloaca (figs. 2 and 3, po).

The comis arteriosus (figs. 7 and 8) is of considerable length, slightly bent towards the
right, and of nearly the same diameter throughout. No special valve separates it from the
ventricle. I find the valves much more regularly arranged than would appear from the
figure given by Garman. They form three longitudinal and six transverse rows (fig. 8).
The largest are those of the distal transverse row, placed close to the end of the conus, and
somewhat more distant from the next row than the five other rows are from each other.
The next largest valves are those of the proximal row, those of the second and third
being smaller, and those of the fourth still smaller, with only partially free anterior margins ;
the valves of the fifth row are quite rudimentary, and two of them merely indicated as
raised papillae, which are confluent with those of the fourth row. Finally, a fourth
intermediate longitudinal series is indicated by two minute valves, belonging to the first
and second transverse rows. The larger valves are provided with tendinous chordae.

Family S p i n a c i d ^.

Spiimx, M. and H.
Spinax spmax, L.

The common European species is reported by Strom ' to be common in Throndjhem
Fjord, at a depth of from 70 to 300 fathoms.

Spinax granulosus.

Spinax granulosus, Giinth., Report on the Shore Fishes, Zool. Chall. Exp., jmrt vi. p. 19,
pi. ii. 2, fig. C.

Habitat. — South-western coast of South America, Station 305a ; depth, 125
fathoms. One specimen, 10^ inches long.

Centrophorus, M. and H.
The two Japanese species here described live at about the same depth as the Atlantic
species, all of which have been hitherto found in the Mediterranean, oft' Madeira, and on

' Norsk. Vid. SeUk. Skrift., 1884, p. 44.

REPORT ON THE DEEP-SEA FISHES. 5

the coast of Portugal. With the exception of a specimen taken near Gloucester on the
coast of Massachusetts, and of three very young examples obtained l)y Bleeker in the
East Indian Archipelago, no other representative of this genus has been found in any
other part of the globe ; and therefore the distribution of this genus is an additional
proof of the extraordinary resemblance of the Japanese and Madeiran marine faunas.

Centropliorusfoliaceus, n. sp. (PI. II. fig. A).

Snout much produced, the mouth being nearer to the first giU-openiug than to the
end of the snout. The distance between the nostrils is two-sevenths of the length of the
prseoral portion of the snout. The labial fold extends a little way along the margins of
the mouth ; the angle of the mouth being received into a deep longitudinal slit in the
skin. The anterior teeth of the upper jaw triangular, erect, the lateral slightly oblique ;
they are arranged in two regular rows. No median tooth in the lower jaw. Pectoral
short, with the lower angle rectangular, not produced. Dorsal spines strong, nearly as
high as the fins. The first dorsal fin rather lower than the second, but with its base
longer, the length of the base (without spine) being two-fifths of the distance between
the two fins. Extremity of the ventral fin a little behind the dorsal spine. The scales
are pedunculate, terminating in three spines, of which the middle is the longest, corre-
sponding to a strong median keel on the scale. Uniform greyish.

Habitat. — Off" Inosima, Japan, Station 232; depth, 345 fathoms. One specimen
(young male), 16 inches long.

Centrophorus ccelolepis.

Centroseymnus cmlolepis, Socage and Capello, Proc. ZooL Soc. Lond., 1864, p. 263, fig. 4; and

Peix. Plagiost., p. 30, pi. ii. fig. 3.
„ Wright, Ann. and Mag. Nat. Hist., 1868, vol. ii. p. 426.
Centropliorvs codolepis, Giinth., Fish., vol. viii. p. 423.

Probably all the European species of Centrophorus live at great depths, but the
present is the only one of which we know this to be the case from actual observations,
made by Dr. E. Percival Wright. He found the Portuguese fishermen fishing for them
in 400 or 500 fathoms, with a Hue of some 600 fathoms in length. "The sharks caught
were from three to four feet long ; as they were hauled into the boat, they fell down into
it as so many dead pigs. There could be no reasonable doubt that they were inhabitants
of the same great depth as Hyalonema." This species is obtained off" the coasts of
Portugal and Madeira, and was once found off" the coast of Massachusetts.

Centrophorus squaimilosus, n. sp. (PI. II. fig. B).

Snout much produced, the mouth being nearly midway between the first giU-
opening and the end of the snout. The distance between the nostrils is two-fiftlis

6 THE VOYAGE OF H.M.S. CHALLENGER.

of the length of the prseoral portion of the snout. The labial fold extends a little way
along the margins of the mouth. Upper lip fringed. Pectoral short, with the lower
ano-le rounded, not produced. The first dorsal fin small, its base (without spine) is shorter
than that of the second, and nearly one-sixth of the distance between the two fins.
Spines very small, scarcely projecting beyond the skin. Extremity of the ventral
fins below the end of the second dorsal. The scales are tricuspid, with a median keel,
and so minute as to give a velvety appearance to the skin. Uniform deep black.

Habitat. — Off Inosima, Japan, Station 232 ; depth, 345 fathoms. One specimen
(adult female), 27 inches long.

The structure of the intestinal tract does not essentially differ from that of the ordinary
littoral or pelagic Selachian type. The stomach consists of two portions ; the anterior is
much the larger, of an elongate form, narrowed towards its posteiior extremity ; it passes
by an abrupt bend into the second reverted portion, which is the narrowest part of the intes-
tinal tract. The commencement of the intestine is a wide diverticulum, separated from the
stomach by the circular pyloric valve. The intestine proper is almost straight ; the spiral
valve commences on the level of the posterior extremity of the stomach, the spire being
composed of fifteen transverse gyrations. Csecal appendage worm-shaped, nearly an inch
long, with a very narrow cavity. The intestinal tract contained nothiiig but the single
beak of a cuttle-fish. The liver consists of two extremely long and flat lobes extending
on the right as well as on the left side from the anterior to the posterior extremity of
the abdominal cavity. Anteriorly they are connected by a short transverse strip not
broader than the lateral portions, and having imbedded in its middle line a gall-bladder
of moderate size. The ovaries are paired, containing mature ova, three in the right half
and five in the left. In the oviducts no separate divisions can be distinguished, the
whole of their cavity being coated with numerous longitudinal folds, the edges of which
are beset with villi. They are confluent anteriorly, and attached in the median line to
the ventral side of the abdominal cavity; their single opening is directed backwards
towards the Fallopian tubes and surrounded by a thick swollen j)ad of soft membrane,
the surface of which is finely transversely lamellated. ^

The valves of the conns arteriosus of the heart are arranged in five transverse
series, each series consisting of three principal valves and as many intermediate smaller
ones.

Centroscyllium, M. and H.
Centroscyllium fabricii, Reinhardt.

This Greenland shark has recently been discovered otf the const of Massachusetts,
whence the British Museum received through the Smithsonian Institution a specimen
captured in 250 fathoms.

REPORT ON THE DEEP-SEA FISHES. 7

Centvoscyllium gmmilatum. n. sp.

The discovery of a specimen of this Arctic genus in the opposite hemisphere is highly
interesting ; unfortunately the specimen is in such a deteriorated condition, that we can
ascertain from it scarcely anything beyond its generic characters. Specifically, it must
be very closely allied to CentroscyUium fabricii, having the same disposition of the fins,
size of teeth and dorsal spines, but the epidermoid productions of the head and body
are much coarser, and in the form of granulations, whilst in CentroscyUium fabricii they
are minute.

Habitat. — Port Stanley, Falkland Islands, Station 311; depth, 245 fathoms. One
specimen, 11 inches long.

Lwmargus, M. and H.
Lsemargus borealis, Scoresby.

Common in the North Atlantic, and frequently found on the surface ; but habitually
living at a considerable depth (150 to 300 fathoms), at least on the coast of Norway. ^

BATOIDEI— RAYS.

Raja, Cuv.
Raja isotrachys, n. sp. (PL 111.).

Snout rather produced, the anterior margins meeting at nearly a right angle. The
width of the interorbital space equals the length of the orbits. The distance between
the outer margins of the nostrils equals their distance from the end of the snout. Teeth
small, each with a point directed backwards towards the interior of the buccal cavity.
Outer pectoral angle rounded, but the margins of the fin would meet at a right angle.
Body and tail entirely covered on the upper surface with minute asperities, each with a
stellate base. No spines on the superciliary margin. A single small spine in the
middle of the back. A series of rather strong spines (eighteen) along the median line
of the tail, none on the sides. Upper parts uniform, brownish-grey ; lower parts smooth,
brownish-black.

Distance between tlie snout and vent, . . . . . 10 inches.

Length of the snout, ....... -^ i,

Width of the body, ....... 13 „

Length of the tail, . . . . . . • 12^ „

1 Strom, Norsh Vid. Selsk. Skrift., 1884, p. 44; CoUett, A^ Mag.f. Naturiid., .wiii., 1884, jj. 117.

8 THE VOYAGE OF H.M.S. CHALLENGER.

Habitat. — South of Japan, Station 235 ; depth, 3G5 fathoms. One specimen,
female.

Raja circularis, Couch.

Of the Sandy Kay, only one specimen, a female, 1 5 inches long, was obtained on the
cruise of the "Triton" in the Faroe Channel, at a depth of 516 fathoms (Station 10,
August 24, 1882). Also CoUett^ reports its occurrence in 130 and 870 fathoms off the
coast of Norway.

The Faroe specimen does not differ in its armature from specimens obtained on the
south coast of England, only the spines on the upper side of the snout and the inter-
orbital spa ;e are somewhat more developed, though in this respect littoral specimens
show likewise some variation.

With regard to colour, it is notable that the spot on each side of the back which, in
littoral specimens, is variegated with yellow, is much smaller in the deep-sea specimen,
and uniformly black, without yellow. The lower parts are nearly uniform blackish-brown,
which colour laps over to the upper side of the ventral fins. Tail with irregular brownish
cross-bands.

Raja radiata, Donovan.

This species, which is widely distributed on the coasts of Northern Europe and North
America, has been met with in the sea between Bear Island and Spitzbergen at depths
of from 127 to 259 fathoms ;' and in Throndhjem Fjord in 250 fathoms.^

Raja hyperhorea (PL TV".).

Baja hyperhorea, Collett, Forhandl. Videusk. Selsk. Christ., 1878, p. 7 ; Norsk. Nordh. Exped.
Zool. Fisk., p. 9, pi. i.

The margins of the snout form a right or a nearly right angle, its extremity being
rounded ; the margin of the body between the snout and the extremity of the pectoral
fin is undulated. Width of the interorbital space considerably exceeding that of the
orbit and spiracle ; eye rather small, about as long as the spiracle. Distance between
the nostrils a little more than their distance from the end of tlie snout. Teeth very
slender, acutely pointed, widely set with narrow base. Outer pectoral angle nearly a
right one.

Sides of the trunk nearly smooth, but the greater part of the pectorals and the margin

1 Forhandl. Vidensk. Selsk, 1880, p. 105, and Nyt Mag. f. Naturvid., xviii., 1884, p. 119.
= Collett, Nor.sk. Nordh. Exped. Fisk., p. 14.

2 Strom, Norsk. Vid. Selsk. Skrift., 1881, p. 79 ; Collett, Nyt Mag. /. Naturnd., xviii., 1884, p. 118.

REPORT ON THE DEEP-SEA FISHES. 0

of the head, also the snout and iutoroi-bital space, are studded with minute or very small
spines resting upon a stellate base. A series of larger spines runs along the median
line of the back and tail, commencing immediately behind the occiput. A group of
three similar spines occupies each side of the shoulder ; a short series composed of three
or four spines along the supraorbital margin and above the spiracle. The spines alono-
the ridges of the snout are also somewhat enlarged. Greyish-brown above with a trace
of a darker spot on each side of the body. Lower parts white, with large sub-
symmetrical brown patches. In very young specimdfis the lower parts are uniform
white.

Habitat. — A large male specimen, 24| inches long, was obtained on the cruise of the
"Knight Errant," at Station 9, on August 23 (1880), in 608 fathoms, together with
three small ones, of which two are males 6i inches long, and one a female 8 inches long.
A fourth very young male specimen was caught at Station 4 in about 400 fathoms.

The Norwegian expedition obtained one male only, at 115 kils. west of the Norsk
Islands, Spitzbergen, at the depth of 4.59 fathoms.

Mr. Collett's description of this species is so detailed, that I need only refer to those
points in which our specimens differ from his, or in which I can supplement his
observations.

The most important difference between the specimens obtained by the Norwegian and
British expeditions is the number of scapular spines, which in the former is only two,
whilst four of our five specimens show three placed in a triangle.

In our old specimen the two dorsal fins are joined at the base, but a small spine
intervenes between them in our young specimens. The young sjsecimens are more
uniformly covered with those minute spinelets described in the adult fish, but the larger
spines are much more acute and prominent, longer and claw-like. The number of the
median series varies: in the adult there are 8-f-19, in the three young males G-f 10,
8 -f- 16, and 11+ 21 ; in the young female 7 + 17.

This deep-sea species of Eay shows some striking peculiarities. The teeth are
remarkably slender, small, irregularly and widely set, different from those of other
British Eays. In young specimens, at any rate, those of the male do not differ from
those of the female. The mucous membrane behind the upper jaw forms a pad with a
lobulated surface. The mucous cavities of the head are extremely wide ; and finally,
the accessory copulatory organs have a spongy appearance and are flexible, the cartilage
by which they are supported being a simple slender rod. Fig. A represents the adult
male three-sevenths of the natural size ; fig. B, a young of the natural size ; and
fig. C is a separate view of the mouth of the adult specimen.

(ZOOL. ClIALL. EXP. — PART LVH. — 1SS6,) T-11 2

to THE VOYAGE OF H.M.S. CHALLENGER.

Raja plutonia.

Raja plutonia, Garman, Bull. Mus. Comp. Zoiil., vol. viii. No. 11, 1881, p. 236.

" Disk, including ventrals, broader than long, subquadrangular, broadly rounded in
front and on the lateral angles ; snout forming a very blunt angle ; margin opposite the
o-ill-openings nearly straight. Tail about one and one-half times the length of the disk,
slender, depressed, with a cutaneous fold on each side near the extremity. Eostral
cartilage short, not extending to the end of the snout. Mouth moderate, slightly
curved, width equalling the distance between the outer angles of the nostrils, and
contained twice in its distance from the end of the snout. Teeth about thirty-two
series (a young specimen). Eyes large, longitudinal diameter of orbit greater than their
distance apart. Interorbital space concave, narrow ; width rather more than two and
one-half times in the distance of the eyes from the end of the snout. Spiracles small.
Anterior nasal valve tubular ; posterior reaching the mouth, free on its outer margin.
Hinder extremity of pectoral broad, roundetl. Ventrals deeply notched, anterior portion
narrow, extending farther from the middle of the pelvis than the posterior

'■' Back and tail covered with small, closely set, stellate-based scales, which bear
elongate, slender, compressed, backward directed points. Larger spines form a supra-
orbital row, and a single one stands on each side of the back of the head. The largest
on the body form a close vertebral series on back and tail. On each side of the shoulder
girdle there is an irregular series of five, and a short distance in front of each of these
stands one or a pair. On each side of the tail there are two series, little smaller thaik
those of the medial row. Smooth below. Very small specimens have not so many
spines.

" Brown, grayish in small to purplish in the largest specimens at hand, with more or
less irregular transverse series of distinctly defined spots of brown, often confluent into
short bands, interspersed among which are spots of white of varying size and shapes.
Tail with cross bands of light and of dark. Dorsals dark. Entire lower sui'face white."

This species was obtained during the cruise of the U.S. steamer " Blake," in fi'om
229 to 333 fathoms, oft' the coast of Florida, in lat. 32° N., long. 78°.

Another deep-sea Eay from the North American coast of the Atlantic has been
noticed by Goode and Bean' under the name of Raja granulata in tlie following terms :
" A remarkable species with the back and ventral surface covered with minute sharp
granular ossifications. Of the same type as Raja lievis (?), and having 30-31
teeth on each side ; the back granulated and slate-coloured ; the ventrals distinguished
by reticulate markings and the claspers slender and scarcely expanded." Obtained on the
Le Have Bank.

' Bull. Essex Inst, vol. si., 1879, p. 28.

REPORT ON THE DEEP-SEA FISHES. 11

Raja hatis, L.

Raja batis, Strom, Norsk. Vidensk. Selsk. Skrift., 1881, p. 80; 1884, p. 46.
„ „ Collett, Nyt Mag. f. Naturvid., xviii., 1884, p. 119.

The common skate, which is generally found near the coast in rather shallow water,
has been observed on the Norwegian coast to descend to 150 fathoms.

■^o^

Rdja vomer, Fries.

Raja vomer, Collett, Forliandl. Vidensk. Selsk. Christ., 1880, p. 106; Nyt Mag. f. Naturvid.,
. 1884, xviii., p. 119.
„ Strom, loc. rit., 1881, p. 81; 1884, p. 46.

1> )»

Inhabiting deeper water than the common skate, not rare at a depth of 70 fathoms,
and descending to, or even beyond, 150 fathoms.

Raja fullonica, L.

Raja fullonica, CoUett, Forliandl. Vidensk. Selsk. Christ., 1880, p. 106; Nyt Mag. f. Naturvid.,
xviii. 1884, p. 119.

Reported by Collett to occur locally on the Norwegian coasts at depths of from
80 to 250 fathoms.

Raja nidrosiensis.

Raja nidrosiensis, Collett, Forhandl. Vidensk. Selsk. Christ., 1882, No. 7, p. 2, c. tab. ; Nyt
Mag. f. Naturvid., xviiL, 1884, p. 121.
„ „ Strom, Norsk. Vidensk. Selsk. Skrift, 1881, p. 80; 1884, p. 47.

Snout long and pointed ; the width of the interorbital space is contained about four
times and one half in the length of the snout. Body above smooth, rough only on the
snout and the upper margin of the eye, in some old specimens also along the front margin
of the disk ; the body below thickly covered with minute asperities. No larger spines
on the disk. The tail in the males with a median series (containing about forty spines),
but none on the sides ; the old females with three series, the median series containing a
varying number of spines, some of which are sometimes irregularly crowded together.
Between the dorsals there are, as a rule, a few spines. The teeth form from forty-one
to forty-four series in the upper, and from forty-one to forty-three in the lower jaw.
Coloration dark greyish-brown above ; the mucous pores marked with black vermicular
spots. Lower surface blackish, without spots.

This species is locally not uncommon on the Norwegian coast, for instance in
Throndhjem Fjord, at a depth of 150 to 200 fathoms. It is one of the larger skates, the
specimens in the British Museum measuring from 38 to 46 inches in width.

12 THE VOYAGE OF H.M.S. CHALLENGER.

Urolophus, M. and H.

Urolophus kaianus.

Urolophus kaianus, Giinth., Report on tlie Shore Fishes, Zool. Chall. Exp., part. vi. p. 37.

Habitat.— OS the Ki Lslauds, Station 192, September 26, 1874; lat. 5° 49' 15" S.,
long. 132° 14' 15" E.; depth, 140 fathoms; bottom, blue mud.

HOLOCEPHALA.

Chimcera, L.
Chimcera monstrosa, L.

During the cruise of the " Knight Errant " a young male was obtained at the depth
of 555 fathoms (Station 4). The length of its trunk is 5 inches. The specimens caught
by the " Triton " are still younger ; two, a male and a female, having the trunk 2\ and 3
inches long, came from a depth of 516 fathoms (Station 10). Finally, a male, which
does not appear to have been long hatched, has the trunk only 1^ inches long ; it came
'^ from 565 fathoms (Station 11).

These specimens are of considerable interest, as they show the gradual development
of certain organs.

The youngest example has the caudal filament least developed, the length of the tail
measured from the vent, being little more than 3 inches, or twice the length of the trunk.
The tail is comparatively much longer in specimens of the next size, but as its extremity
is broken off in both, the exact proportion cannot be ascertained. In the largest of these
young specimens, with the trunk 4^ inches long, the tail measures not less than
17 inches. Of the fins only the first dorsal with its spine is developed. Of the anal
only a portion has appeared as a low ridge, but there is no trace of the second dorsal or
of the caudal.

The development of the prehensile organ on the upper part of the snout, which is
peculiar to the male sex in Chimoira, keeps pace with that of the claspers. This
organ is visible in our youngest specimen, which evidently was hatched only a few
days, as a narrow cartilage of whitish colour entirely covered by the skin, but visible
through it. It has not made as great progress in the largest of the young specimens,
and therefore does not seem to become detached from the head before the individual
attains to sexual maturity.

REPORT ON THE DEEP-SEA FISHES. 13

The claspers are visible from the earliest stage, and although only 2 mm. long, show a
distinct bifurcation.

The occurrence of these specimens shows that Chimcera is a deep-sea fish, and one
which propagates its species in deep water. If the propagation of Chimasra really takes
place in deep water only, this circumstance would account for the scarcity of young
specimens in collections ; and also the ova, which have been described as Chimceroid,
seem to be rather those of Callorhynchus than of Chimoera, and, so far as I know, there
is no well authenticated egg of the latter in any collection.

Chimcera affinis.

Cliiriioera affijiis, Capello, Journ. Math. Phys. e. Xat. Lisb., iv. p. 314, pi. iii., 1868.
„ „ Jordan, Rep. Comm. Fish, for 1884 (1885).

„ plumhea, Gill, Bull. Phil. Soc. Washington, Decemher 22, 1877.
ahhreviafa, Gill, Proc. U.S. Nat. Mus., vol. vi. p. 254, 1884.

Scarcely distinguished from Chimcera monstrosa. Has been found first on the coa,st of
Portugal, and later on the North American side of the Atlantic, at depths varying from
200 to 1200 fathoms.

ACANTHOPTERYGII.

Family P e r c i d .e.

Anthias, Cuv.

Anthias megalepis.

Anthias megalejns, Giinth., Report on the Shore Fishes, Zool. ('hall. Exp., part vi. p. 37,
pi. xvi. fig. E.

Habitat. — Off the Ki Islands, Station 192 ; depth, 140 fathoms.

Centropristis, Cuv. Val.
Centropristis pleurospilus.

Centropristis pleurospilus, Giinth., Report on the Shore Fishes, Zool. Chall. Exp., jiart vi. p. 37,

pi. xvi. fig. D.

Habitat.— OS the Ki Islands, Station 192; depth, 140 fathoms.

14

THE VOYAGE OF H.M.S. CHALLENGER.

Scomhrops, Schlegel.

Scomhrops chilodipteroides, Blkr.

This fish, which was originally described by Schlegel in the Fauna Japouica, seems
to be scarce on the coast of Japan, as it is not distinguished by a vernacular name. The

Challenger Expedition obtained one specimen only,
16 inches long, off Inosima, at a depth of 345
fathoms. Like other Japanese fish Scomhrops re-
appears in the AVest Indies, Poey having described
a closely allied species under the name of Latehrus
ocidatiis} The reason why I hesitate in specifically
identifying the Cuban with the Japanese fish is
the circumstance that Poey figures the strong teeth
of the jaws as distinctly barbed, although he
singidarly enough does not allude to this peculiarity
in the description. Difi'erences in the statements
of the number of the scales are of much less weight
in regard to these fishes, because the transverse
series are rather irregularly arranged and do not
correspond with the number of scales along the
lateral line. Poey also found only ten pyloric
appendages in his specimen. He states that the
fish is rare and an inhabitant of great depths.

Scomhrops shows some noteworthy peculiarities
in the structure of its abdominal organs. The gall-
bladder [g) is excessively prolonged, lying behind
the lower intestine and extending to the end of the
abdominal cavity. The stomach [st] is very short
and small, but the pyloric appendages {p), of which
there are eighteen, are very long and wide. Seven-
teen of them are convoluted and form a large
bundle, whilst the eighteenth {p>') is straight, accom-
panying the anterior portion of the intestine. The
intestine ({) makes only one entire convolution.
The air-bladder is large, attached to the walls of the
abdomen, with the ventral part of its outer tunic thickened and giving support to the miich
developed glandular red bodies.

1 Jlem. Hist. Nat. Cuba, ii., 1858, p. 168, Tali. xiii. fig.s. 11, 12 ; Tab. xiv. fig. 2.

Fig. 1. — Scomhrops chilodiptcrindcx. st, .stomach ;
i, i, intestine ; p, pyloric ajipemlages ; p', pyloric
appendage separated from the re.<it ; I, liver, part of
which has been removed ; g, gall-bladder ; a, end
of ductus choledochus ; v, vent , o, o, ovaries.

REPORT ON THE DEEP-SEA FISHES. 15

Acropoma, Schlegel.

Acropoma philippinense.

Acropoma phili-ppimnse, Giinth., Report on the Shore Fishes, Zool. Cball. Exp., part. vi. p. 51.
Habitat. — Philippine Islands, Station 201 ; depth, 82 to 102 fathoms.

Propoma, Gthr.

Propoma roseum.

Propoma roseum, Giiuth., Report on the S' ore Fishes, Zool. Chall. E.xp., part vi. p. 39, pi. x.v.
fig. B.

Habitat.— Off the Ki Islands, Station 192, September 26, 1874; lat. 5° 49' 15" 8.,
long. 132° 14' 15" E.; depth, 140 fathoms; bottom, blue mud.

Only two other bathybial Percoid fishes are known at present ; they were discovered
in the Japanese sea by Doderlein, who characterises them thus : —

Malacichthys.
Malakichfliys, Doderlein, Denkschr. d. k. Akad. d. Wiss. Wien, xlvii., 1883, p. 210.

Form of the body oval, similar to Ambassis. The two dorsals united by a low
membrane ; anal with three spines. Prseoperculum denticulated ; operculum with two
feeble points. Bones of the head very thin, cavernous ; eye large. Very narrow bands
of villiform teeth in the jaws, on the vomer and palatine bones, without canines. Head
nearly entirely scaly. Mouth wide, oblique, with projecting mandible. Scales of
moderate size, ctenoid, deciduous. Seven branchiostegals ; pseudobranchise. Lateral
line complete. Pyloric appendages in small number (four). Air-bladder small.
Aladominal cavity and pharynx black.

Malacichthys griseus.

Mahikicldliyg griseus, Doderlein, lor. rit., xlviii., Tab. ii. fig. 1.

D. 9x^u, A. -^, V. 1, L. lat. 45, L. transv. .--ro-

The height of the body is contained twice and three-fourths or twice and five-sixths,
the length of the head twice and a half in the length of the l)ody; the diameter of the
eye twice and two-thirds to twice and three-fourths, the width of the interorl)ital space
rather more than five times, and the snout thrice and two-thirds in the length of the

f

16 THE VOYAGE OF H.M.S. CHALLENGER.

head. Dorsal spines rather strong, curved, the fourth the longest, its length being
contained twice and one-third in that of the head. Mandible with two points at the
chin. Coloration uniform.

Several examples were obtained from " great depths " at Tokio, where the fish is not
rare. The largest example was 8 inches long.

Synagrojjs.
Melanostoma,^ Doderlein, Denkschr. cl. k. Akad. d. Wiss. Wien, xlviii., 1883, p. 5.

Shape of the body rather elongate. Upper side of the head with muciferous cavities.
Prseoperculum finely denticulated; operculum with two points. Two dorsal fins, the
first with nine slender spines, the second rather short. A narrow band of villiform teeth
in the jaws, on the vomer and palatine bones, with the addition of a pair of canine teeth
in the upper jaw, and a series of similar teeth in the lower. Scales large, thin, and
cycloid. Air-bladder present. Pyloric appendages in small number (six to seven).
Pharynx and peritoneal cavity black.

Synagrops japonicus.

Melanostoma japonicum, Doderlein, loc. cit., Taf. i. fig. 2.

B. 7, D. 9xV, A. I, p. jL, V. 1, L. lat. 31 ( -I- 5 caudal).

The height of the body is one-fourth, the length of the head nearly one-third of the
total (without caudal). Eye longer than the snout, contained thrice and two-thirds in
the length of the head. The mouth extends to below the midtUe of the eye, is rather
oblique, with somewhat projecting lower jaw. Uniform blackish.

From " very great depths," and rare at Tokio ; Doderlein obtained one example only,
9 inches long.

Family Scorp^nid^.

Scorpiena, Gthr.

On the distinctive characters of this genus and Sebastes, see Giinther, Fisch. d.
Siidsee, p. 74.

' Preoccupied. — I may observe here that the fish described by Steindachner in the same paper, under the name of
Oypselichthijs japonicus, n. gen. et sp. (p. 14, pi. vii. tig. 1), is a species of the genus Cahiceps, and does not belong to the
"Maenini," but to the family Nomeidae.

REPORT ON THE DEEP-SEA FISHES. 17

Scorpasna percoides, Solauder.

Scorpeena harathri, Hector, Trans. New Zeal. Inst., vol. viL p. 245, pi. x., 1875; Ann. ;iuil
Mag. Nat. Hist., vol. sv., 1875, p. 80.

This species, wliich is not uucommon along the coasts of Southern Australia, Tasmania,
and New Zealand, descends to a depth of 400 fathoms, so far as is known at present. In
the Eeport on the Shore Fishes of the Challenger Expedition, I have already recorded
its occurrence at Twofold Bay in 120 fathoms. Another specimen, 4 inches long, was
obtained in 275 fathoms at Station 166, in the neighbourhood of New Zealand. Finally,
a very young specimen, 2 inches long, captured oif Matuka, Fiji Islands (Station 173),
in 215 fathoms, on July 24, 1874, belongs without doubt to the same species.

The specimen from which Dr. Hector drew up the description of his Scorpsena
harathri, and which is said to have been obtained in 400 fathoms off Cape Farewell, is
also identical with this species. The length of the third and fourth dorsal spines varies
somewhat, being sometimes rather more, and at other times rather less than two-fifths
of the length of the head.

I have now had an opportunity of examining a skeleton of Scorpsena percoides ; its
spine is composed of ten abdominal and fifteen caudal vertebrae, and therefore this
species must be referred to Scorpiena, of which genus the vejtebral formula j^ is
characteristic.

Scorpsena dactyloptera, de la Eoche.

Sebastes dadylopterus, Giinth., Fish., ii. p. 99.

,, ,, Collett, Norges Fisk., p. 19.

„ ,, Lilljeborg, Sveriges Fisk., p. 107.

This species, which has been known for many years from the Mediterranean and

Madeira, occurs also on the coast of Norway, where it is not uncommon in depths of from

100 to 300 fathoms.

Other species of this genus also occur at considerable depths, Ijut as it is not known to
what depth they descend, they are omitted from the bathybial fauna at present.

Sebastes, Gthr.
Sebastes mannus.

Perca marina, Linne.
Sebastes norwegicus, Cuv. Val.

„ „ Collett, Norges Fisk., p. 19.

Sebastes marinm, Liitk., Vid. Meddel. uat. Foren. Kjobenhavn, p. 358, 1876.

„ „ Collett, Norsk. Nordh. Exped., Fisk., p. 15; Vidensk. Selsk. Forhandl. Christ.,

1880, No. 1, p. 7.
Goode, Proc. U.S. Nat. Mus., vol. iii. p. 480, 1881.
„ „ Lilljeborg, Sveriges Fisk, p. 92.

On the Norwegian expedition (1876) specimens were obtained at depths varjnng from
123 to 147 fathoms, and others on the American coast by the U.S. steamer "Fish

(ZOOL. CHALL. EXP. — PART LVII. — 1886.) Lll 3

18 THE VOYAGE OF H.M.S. CHALLENGEE.

Hawk," at 155 fathoms. The observation which I have made on previous occasions, viz.,
that the young of many deep-sea fishes live on the surface, or much nearer to it than
the adult, seems to be fully borne out by this species. Collett remarks that during the
breeding season individuals are seldom taken at a depth less than 100 fathoms ; the
majority probably producing their young ^ in far greater depths. The fry rise towards
the surface shortly or perhaps immediately after birth, choosing for their haunts the
upper strata of the sea, and do not descend to any considerable depth till they have
attained a length of about 50 or 60 mm.

Sebastes viviparus.

Sebastes viviparus, Kroyer, Nat. Hist. Tidsskr., 1844-45, p. 275 ; and in Gaimard, Voy. Scandin.
Zool. Poiss. pi. vi.
Strom, Norsk. Vid. Selsk. Skrift., 1881, p. 73 ; 1884, p. 16.
„ „ Lilljeborg, Sveriges Fisk., js. 101.

„ regiilas. Fries ocli Ekstr., Skand. Fisk., pi. xlix.

Rather common on the coasts of Scandinavia, at a depth of from 50 to 300 fathoms.

Sebastes macrochir.

Sebastes macrochir, Gunth., Keport on the Shore Fishes, Zool. ClialL Exp., part vi. p. 65,
pi. xxvii.

This fish was discovered oif Inosima in 365 fathoms, and therefore is to be included
among the deep-sea group. For the sake of comparison it was described in the Report
on the Shore Fishes. /

Sebastes hexanema.

Sebastes hexanema, Giinth., Report on tho Shore Fishes, Zool. Chall. Exp., part vi. p. 40.
— Habitat. — Off the Ki Islands, Station 192 ; depth, 1.40 fathoms.

Sebastes oculatus, C. V.

Sebastes oculatm, Giinth., Report on the Shore Fishes, Zool. Chall. Exp,, part vi. p. 20.

A
Vert, \^, Several specimens were obtained at Stations 306 and 307, near Magellan

Strait, in 147 and 345 fathoms. This species, however, lives at certain times or localities

much nearer to the surface, and is not uncommon along the Antarctic coasts of South

America.

1 This species is viviparous.

REPORT ON THE DEEP-SEA FISHES. 19

Setarches, Johnson.

Setarches fidjiensis, n. sp. (PI. I. fig. C).'

D. 10 I ^. A. l P. 23.

The height of the liody is one-third of the total length (without caudal); the
length of the head two-fifths. Head scaleless, without prominent spines on the vertex
and with parallel ridges ; interorbital space flat, as wide as the eye, the diameter
of which is two-ninths of the length of the head and two-thirds of that of the snout ;
upper jaw overlapping the lower, maxillary extending to below the middle of the
eye ; very narrow bands of villiform teeth in the jaws on the vomer and palatine
bones. The largest spines of the head are three at the angle of the prseoper-
culum ; smaller ones are distributed on the praeorbital, the lower prseopercular margin,
and the operculum. The fourth dorsal spine is the longest, two-fifths of the length of
the head ; the third anal spine is longer than the second. Pectoral extending to the anal
fin. Body covered with minute cycloid scales. Lateral line wide. Body iiTegularly
mottled with brown.

Habitat. — Off Matuku, Fiji Islands, Station 173 ; depth, 315 fathoms. One specimen,
3 in. long.

Only one species, represented by a single example from Madeira, was previously
known of this genus, which is evidently a deep-sea modification of Sehaates; the Fiji
species so much resembles the one from Madeira as to leave no doubt whatever -nith
regard to their natural affinities. They are fishes inhabiting moderate depths, and I
should say that they are not likely to descend below 500 fathoms.

Since the above lines were written, a third species has been described by Goode,''
under the name of Setarches parmatiis. Specimens were obtained off the southern coast
of New England and in lat. 34° N., at depths of 120 and 178 fathoms. They are young,
only 52 and 53 mm. long, possess only ten dorsal spines, small cycloid scales, and a deep
body, the height of which is three-eighths of its length.

Bathysebastes.

Bathysehastes, Steindachner mid Duderlein, Denkschr. d. k. Akad. d. Wiss. Wien, 1884,
xlix. p. 207.

This genus is evidently closely aUied to Setarches and Lioscorjpius, with either of

which it may have to be united ; it has been characterised thus : —

1 This specimen was accidentally destroyed by the artist to whom it had been entrusted for the purpose of being
drawn. The figure was finished before the accident happened, but could not be compared by myseK with the
specimen.

2 Proc. U.S. Xat. Mus., 1881, p. 480.

20 THE VOYAGE OF H.M.S. CHALLENGEE.

The superficial bones of the skull with wide muciferous cavities. Cleft of the mouth
unusually wide. Bands of villiform teeth in the jaws, on the vomer and palatine bones.
Scales very small, cycloid ; upper side of the head scaleless ; [scales on the lateral parts
of the head hidden under the skin].^ Branchiostegals seven.

Otherwise resembling Sebastes.

Bathysehastes albescens.

Bathysehastes albescens, Steindachner u. Doderlein, Denksckr. d. k. Akad. d. Wiss. "Wien,

1884, xlix. p. 207.

D. if. A. |. P. 21.

The posterior end of the maxillary is vertically a little in front of the hind-margin
of the eye, which is contained five and two-fifths in the length of the head. The
pectorals reach to the vent. Yellowish-white.

One specimen, 12 inches long, was obtained in the Sea of Japan, but nothing definite
is known about the depth which it inhabits.

Lioscorpius, Gthr.
Lioscorpius longiceps.

Lioscorpiiis longicepn, Giinth., Eeport on the Shore Fishes, Zool. Chall. Exp., part vi. p. 40,
pi. xvii. fig. C.

^ Habitat.— OS the Ki Islands, Station 192 ; depth, 140 fathoms.

Family Berycid^. '
Hoplostethus, C. V.

Body deep, compressed, covered with scales of moderate size and more or less distinct
ctenoid structure, rather irregularly arranged, those of the lateral line being the largest.
Head very large ; the superficial bones being deeply sculptured to receive wide muci-
ferous cavities which are covered by thin skin only. Mouth very wide, oblique ; the jaws
and palatine bones armed with villiform teeth, the vomer being toothless. Eye very
large. Eight brc.-^jchiostegals ; gill-openings very wide, gill-laminae very short. Prse-
operculum armed with a flat spine. Abdomen protected by dermal scutes which form a
serrated edge. One dorsal fin, the anterior rays of which are spinous ; ventrals with six
soft rays ; pectoral symmetrical ; caudal deeply forked. Air-bladder simple ; pyloric
appendages numerous.

One species only is known.

' Useless for generic distinction.

REPORT ON THE DEEP-SEA FISHES. 21

Hoplostethus mediterraneum.

Hoplostethus mediterraneus, Cuv. et Val., iv. p. 469, pi. xcvii., his.
„ „ Guichen, Explor. Alger, poiss., p. 42.

» ,. Giinth., Fish., vol. i. p. 9 ; Anu and Mag. Nat. Hist., 1878, vol. i p

485.
„ „ Jordan and Gilbert, Synopsis, p. 458.

„ „ Steindachner, Denkschr. d. k. Akad. d. Wiss. Wien, 1883, xlvii. p.

218, tab. i.
Trachichthys pretiosna, Lowe, Proc. Zool. See. Lond., 1839, p. 77; Fish. Madeira, p. 55, pi. ix.
Hoplostethus japonicus, Hilgeudorf, Sitzungsb. d. Gesellsch. naturf. Freunde, Berlin, 1879,

p. 78.

D. ^^. A. f. V. i. L. lat. 28-29. Vert, fi-

Specimens of this species have been discovered at distant intervals of time at
considerable depth (the precise depth is not known) in the western parts of the
Mediterranean, off Madeira, and recently also in the Sea of Japan. Dr. Hiloendorf
was of opinion that he could specifically distinguish Japanese specimens by a somewhat
larger number of abdominal scutes. This would have been a character insignificant
enough, even if the Japanese specimens had not sometimes the same number of scutes
as the Mediterranean. A more important difference seems to be the structure of the
scales, which I find in Japanese specimens, on the whole, less strongly ctenoid than
in Madeiran. But even in this respect there is no constancy in specimens from either
of the two localities.

A specimen 3 inches long has lately been dredged by the U.S. Fish Commission,
off Chesapeake Bay.

Trachichthys, Shaw.

Body compressed, more or less deep, covered with small ctenoid and generally rough
scales, which are rather irregularly arranged. Abdomen protected by dermal scutes,
which form a serrated edge. Head very large, the superficial bones being deeply
sculptured to receive wide muciferous cavities which are covered by thin skin only.
Mouth very wide, oblique ; villiform teeth in the jaws and on the vomer and palatine
bones. Eighty branchiostegals ; gill-openings very wide, gill-laminaj very short. Supra-
scapulary and angle of the prseoperculum armed with a spine each. One dorsal fin, the
anterior rays of which are spinous ; ventrals with six soft rays ; pectoral symmetrical ;
caudal deeply forked.

Lowe is right in stating that Hoplostethus is scarcely entitled to generic rank, the
whole difference between it and Trachichthys being the absence or presence of vomerine
teeth. The structure of the bones of the head, the development of large muciferous
cavities, the large eye, the more or less intense black colour of the pharyngeal and
branchial cavities, and finally the mode of occurrence, clearly indicate that the species of

C

22 THE VOYAGE OF H.M.S. CHALLENGER.

this genus belong to the deep-sea fauna, although the actual depth to which they may-
descend is known in one species only. The other species are known from one or
two individuals only, which were picked up in an exhausted condition floating on the
surface.

The following are the species known of this genus : —

Trachichthys australis.

Traehichtliys australis, Shaw, Nat. Misc., p. 378.
„ ,, Giintli., Fish., i. p. 10.

D 3 A 2-3

Scales small and very rough ; eight or nine abdominal scutes. The height of the
body is a little more than one-half of its length, without caudal. Suprascapular spine
longer than that of the angle of the prseoperculum. A black band along each caudal
lobe, the anterior rays of the dorsal and anal fins black.

Besides the diy typical specimen I have seen only one other, 2 inches long, which
also is stated to have come from Australia.

Trachichthys jacJcsoniensis.

Trachichthys australis, Castelnau, Proc. Linn. Soc. N.S.W., 1879, vol. iii. p. 364.
,, jacksoniensis, IVTacleay, Tbid., vol. v. p. 511.

I fully agree with Mr. Macleay that the fish described by Castelnau as Trachichthys
australis cannot be that species, provided that the characters are correctly stated.
But it is somewhat unfortunate that Mr. Macleay himself has not confirmed the more
important of Castelnau's statements. Castelnau states that his specimen had no teeth on
the palate ; if that be correct, the fish should be referred to Hoplostethiis.

Scales rough ; abdominal scutes ten. The height of the body is rather more than
one-half of its length, without caudal. Fins coloured as in Trachichthys austixtlis.

One specimen, 5^ inches long, was found in Port Jackson on the 19th of September
1877.

Trachichthys elongatus (PI. V. fig. C).

Trachichthys elongatus, Giinth., Fi.sh., i. p. 10.

D. j^. A. f. L. lat. ca. 65.

Eleven or twelve abdominal scutes ; the height of the body is one-third of its
length, without caudal ; suprascapulary spine very small, much smaller than that of the

REPORT ON THE DEEP-SEA FISHES. 23

prEeoperculum, which is also very short. A l)lack baud along each of the caudal lobes
and another in front of the soft dorsal and anal fins.

The two typical specimens, of which one, 4 inches long, was found near the Great
Barrier Island (New Zealand), seem still to be the only ones known.

TracMchthys fernandezianiis, n. sp.

D. ^, A. ^, L. lat. ca. 85.i

The height of the body is contained twice and three-fourths in the total length,
without caudal, the length of the head thrice. Bones of the head deeply sculptured as
in the other species of the genus. Eye two-fifths of the length of the head. The
suprascapulary spine is nearly of the same size as that of the prseoperculum. Scales
studded with minute spines. Abdominal scutes ten. Spines of the fins moderately
strong ; and also the rudimentary outer rays of the caudal fin are modified into spines.
The dorsal spines increase in length posteriorly, the length of the last being two-sevenths
of that of the head. Pectoral fin not extending to the anal. Body with a coppery tinge ;
fins yellowish.

Two specimens, preserved in a dry state, were contained in the series of Chilian fish in
the London Exhibition of 1884, and presented by the Chilian Government to the British
Museum. They were stated to have been captured at Juan Fernandez, and are 5 inches long.

#

TracMchthys traillii (PI. L^^ fig. A).

TracMchthys traillii, Button, Ann. and Mag. Nat. Hist., 1875, vol. xvi. p. 315; or Trans. New
Zeal. Inst., vol. viii. p. 212.
„ „ Arthur, Trans. New Zeal. Inst., 1885, vol. xvii. \\ 162, pi. xiv. fig. 2.

D. xV A. xV V. I. L. lat. 95 (118). Ccec. pyl. 11.

The height of the body is contained twice and one-third in the total length (without
caudal), the length of the head thrice. The bones on the upper side of the head deeply
sculptured, the anterior ridges terminating in a pair of small rostral spines projecting
above the mouth. Eye one-third of the length of the head. Suprascapulary and oper-
cular spines subequal in length. The four anterior dorsal spines are shorter than, and the
fifth is nearly equal to, the diameter of the eye. Scales rough, ctenoid, irregularly
arranged. Abdominal scutes eleven. The ventrals nearly reach as far back as the
pectorals, which, however, do not reach the anal fin. Fins yellowish.

The specimen from Otago described and figured here, shows a very extraordinary,
and probably abnormal position of the vent, which is placed between the ventral fins, in
front (and not, as usual, behind) the series of abdominal scutes (fig. a).

1 The exact number of the scales cannot be ascertained, both specimens being dried and thickly covered with varnish-

24 THE VOYAGE OF H.M.S. CHALLENGER.

A specimen 7-g inches long was found dead and floating on the surface of the water
near Stewart IsLand ; a second of the same length was caught in Otago Harbour,
September 6, 1884 ; and a third smaller one since that date.

Trachichthys macleayi.

TracMehthys macleayi, Johnston, Pap. R. Sec. Tasman., 1880, p. 56.

This is probably the same species as the preceding, but described as having thirteen
abdominal scutes. The scales of the lateral line are said to be about fifty in number,
but as they are much larger than the other scales, no inference can be drawn from this
statement as to the distinctness of the two species. This species was described from a
.specimen, 9^ inches long, obtained at the mouth of the estuaiy of the Derwent.

Trachichthys intermedius (PI. V. fig. D).

Trachichthys intemiedius, Hector, Trans. New Zeal, lust, vol. vii. p. 245, pi. xi. fig. 18a.
D. i\. A. T^j-. L. lat. 40.

The height of the body is contained twice and one-third in the total length, without
caudal ; the length of the head twice and one-half. Bones of the head sculptured in the
same fashion as in the other species of the genus. Eye rather larger than one-third
the length of the head. Suprascapulary spine smaller and shorter than that of the
prseoperculum. Scales thin, but wath their surface studded with minute spine.s.
Abdominal scutes nine. Spines of the fins rather strong ; also the rudimentary outer
rays of the caudal fin are modified into spines ; the dorsal spines increase in length
posteriorly, the length of the last being one-half of that of the head. Pectoral
extending to the middle of the anal fin, ventral to the vent. Silvery, tips of the caudal
lobes and top of the dorsal fin black.

Two specimens were collected by the Expedition ; one, 3 J inches long, on the east
coast of New Zealand, at Station 166; depth, 275 fathoms.

The specimen described by Dr. Hector was only 27 inches long, and obtained of!"
Cape Farewell in 400 fathoms.

Trachichthys darwinii.

Trachichthys darwinii, Johns., Proc. Zool. Soc. Loud., 1866, p. 311, pi. xsxii.

„ japo7iicus, Steindachner und Ddderleiu,Deukschr. d. k. Akad. d. Wiss. Wien, 1883,

xlvii. p. 218, tab. ii.

D. ^V A. ^. Ccec. pyl. 13.
This species differ.^ from the Antarctic in having the bones of the head more
solid, narrower muciferous channels, a smaller eye, and the spinous dorsal fin

EEPORT ON THE DEEP-SEA FISHES. 25

more differentiated from the soft. The scales are small; abdominal scutes ten.
The height of the body is. less than one-half of the total length without caudal; the
diameter of the eye two-ninths of the length of the head. No projecting suprascapulary
spine. The third and fourth dorsal spines are the longest, and the seventh is shorter
than the eighth.

Only one specimen, 19 inches long, w\as obtained off Madeira in the month of April.
Mr. Johnson adds that from the protruded stomach and inflated membranes about the
eyes it may be inferred that the fish came from a great depth. Like so many other
Madeiran fishes, this species occurs also in Japan, where it was met with by Doderlein,
who seems to have been unacquainted with Johnson's description.

Anoplogaster, Gthr.

Body compressed and deep, covered with minute asperities ; abdomen without enlarged
dermal scutes; head large, with thin bones deeply sculptured to receive wide muciferous
cavities. Mouth very wide and oblique; jaws armed with bands of small teeth which
are somewhat larger and of unequal size in the lower jaw; no teeth on the palate. Eight
branchiostegals ; gill-openings very wide. Suprascapulary and angle of the prasoperculum
armed with a spine. One dorsal fin, without spinous division ; ventrals with six soft
rays. Air-bladder small, pear-shaped.

Anoplogaster cornutus.

Hoplostethus cornutus, Cuv. Val., ix. p. 470.
Anoplogaster cornutus, Giinth., Fish., i. p. 12.

„ „ Lutken, Oversigt K. D. Vid. Selsk. Forhaudl., 1877, p. 181, tab. v. figs.

4-7 (fig. opt).

B. 8. D. 17. A. 9-10. V. (0) 7. C. pyl. 6. Vert. 26.
Of this singular fish only very few specimens are known, and, with the exception of
one, all were taken from the stomachs of pelagic fish of prey, one in lat. 2G°, three in lat.
31° N. and long. 40° W., and one in lat. 25° N. and long. 31° W.; all in the Atlantic.
The largest of these specimens is only 77 mm. long. Lutken has made the interesting
observation that in very young specimens (10 mm. long), no ventral fins arc
developed, and that the spines on the head are much elongate, forming a very effectual
armature.

Caulolepis.

Caulolepis, Gill, Proo. U.S. Nat. Mus., 1884, vol. vi. p. 258.
Closely allied to Anoplogaster, which it also resembles in the form of the body.
Body covered with pedunculated leaf-like scales. A pair of very long teeth in front of

(ZOOL. CHALL. ESP. PART LVII. — 1886.) "^^^ *

26 THE VOYAGE OF H.M.S. CHALLENGER.

the upper jaw closing in front of the lower ; a similar pair of still longer teeth in the
lower jaw received in grooves of the palate. On the sides of each jaw two long teeth
terminating in bulbous tips ; a row of minute teeth on the posterior half of the
maxUlaries. Palate toothless.

Caulolepis longideiis.

Caulolepis longidens, Gill, loe. cit.

D. ■^. A. |. Eyes small, black.

Habitat. — A single specimen of this interesting form (size not stated) was obtained
by the U.S. steamer " Albatross," in the Atlantic; lat. 39° 27' N., long. G9° 56' W. ;
depth, 1346 fathoms.

Melamphaes.

Metopias, Lowe, Proc. Zool. Soc. Lond., 1843, p. 90.
Melamphaes, Giinth., Cat. Fish., v. p. 433.

Head large and thick, with nearly all the superficial bones modified into wide
muciferous channels. Cleft of the mouth of moderate width, obliquely descending
backwards, with the jaws nearly equal in front. A narrow band of villiform teeth in
both the jaws ; palate toothless. Eight branchiostegals ; pseudobranchise present ; no
barbels; opercles not armed. Scales large, cycloid, rather irregularly arranged. One
dorsal ; caudal forked ; anal spines very feeble ; ventrals with seven rays.

The formation of the head, the black colour of the body, together with the circumstances
attending the capture of the three specimens first known, clearly indicate that the fishes
of this genus are inhabitants of the depths of the ocean. Lowe's two specimens were
picked up at the surface, near Madeira, evidently in an exhausted condition ; whilst the
specimen described by Liitken was found in the stomach of a dolphin. The discoveries
by the Challenger, and by the United States S.S. "Albatross," have proved the
surmise ^ of the bathybial nature of these fishes to be correct.

The following is a list of all the species known : —

Melamphaes microps.

Scopelm microps, Giintli., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 186.

B. 8. D. xV A. I P. 14. V. f L. lat. 35.

The height of the body is one-fourth of the total length (without caudal), the length
of the head one-thurd ; eye one-seventh of the length of the head, and rather more

1 Giinther, he. cit.

HEPORT ON THE DEEP-SEA FISHES.

27

than one-half of that of the snout. Mouth oblique, with the lower jaw rather prominent,
and with the maxillary extending to the vertical from the hind-margin of the eye. The
teeth are very small, rather irregularly placed, so as to appear at places to form a
double and at others a single series. The interior internasal space is occupied by a pair
of muciferous cavities separated by a strip of striated skin, which is narrower than
deep, and much narrower than in Melamphaes typhlops. Branchiostegals long and
closely set. No spines on the neck.

The spines of the fins are very weak, not stronger than the rays. End of the dorsal
fin opposite to the origin of the anal, the rays of which are shorter than those of the
dorsal. Caudal fin very short, and covered with scales at the base. Pectoral not quite
as long as the head, and not reaching to the vent. Ventrals much shorter. Black ;
mouth black ; fins yellowish.

Millims.

Total length, ........

120

Length of snout, ......

10

Length of eye, .......

H

Length of head,. ......

35

Length of pectoral fin, ......

29

Distance of snout from origin of dorsal,

41

Distance of snout from vent, .....

69

Habitat. — Between the Cape of Good Hope and Kerguelen Island, Station 146 ;
depth, 1375 fathoms. One specimen.

Melamphaes typhlops (PL V. fig. A).

Metopias typhlops, Lowe, Proc. Zool. Soo. Lond., 1843, p. 90, and 1850, p. 125.
Melamphaes typhlops, Giinth., Cat. Fish., v. p. 433.

B. 8. D. i^r. A. f. p. 15. V. f L. lat. 25. L. transv. 7.

Eye small, one-sixth of the length of the head, and two-thirds of that of the snout.
Ventral fins not quite as long as pectorals, not reaching to the vent. Black.
Habitat. — Atlantic, near Madeira.

Melamphaes megalops (PI. V. fig. B).

Melamphaes megalops, Liltken, Oversigt K. D. Yid. Selsk. Forhandl., 1877, p. 176, tab. v.
figs. 1-3,

B.

D. 3

A i

P. 10-11. V. 4.. L. lat. 34. L. transv. 9.

Eye rather large, more than one-fourth of the length of the head, and much longer
than the snout. Ventral fins at least as long as pectorals, reaching beyond the vent.

Black.

Habitat. — Atlantic, south of the Azores.

28 THE VOYAGE OF H.M.S. CHALLENGEE.

The single specimen known was taken from the stomach of a Corypliwna ; and the
skin covering the head and enclosing the muciferous cavities is destroyed by the action
of the gastric juice so as to render the ridges of the skeleton of the head more conspicuous
than they are in a living or well-preserved example.

Melamphaes crassiceps (PI. VIII. fig. B).

Scopelus crassiceps, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 185.
D. /j. A. gL. P. 14. V. f L. lat. 28.

The height of the body is one-fourth of the total length (without caudal) ; the
length of the head one-third ; the least depth of the tail is two-fifths of its free portion.
Head very thick with short snout. Eye small, one-seventh of the length of the head,
and one-half of that of the snout ; posterior margin of the prseoperculum descending
obliquely backwards; lower jaw slightly prominent ; cleft of the mouth rather oblique;
the maxillary reaches to behind the eye, and is moderately dilated behind. Origin of
the dorsal fin nearer to the extremity of the snout than to the caudal fin, and immediately
behind the base of the ventrals ; its last ray is above the anterior anal rays. Pectoral
fin narrow, nearly as long as the head, reaching to or beyond the end of the anal fin.
Black.

All the specimens are in an indifi'erent state of preservation ; the bones are extremely
soft, and the wide muciferous channels have collapsed, most of the covering membrane
being destroyed. The scales are lost.

Habitat. — Mid-Atlantic, Station 107 ; depth, 1500 fathoms. One specimen,
2 inches long.

Off" Pepnambuco, Station 120; depth, 675 fathoms. One specimen, 2^ inches long.

Midway between Cape of Good Hope and Kerguelen Island, Station 146 ; depth,
1375 fathoms. One specimen, 6| inches long.

North of New Guinea, Station 220 ; depth, 1100 fathoms. One specimen, 2f inches
long.

Melamphaes mizolepis.

Scopelus mizolepis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 185.

Height of the body two-sevenths of the total length (without caudal); the length of
the head rather less than two-fifths ; the least depth of the tail is one-half of its free
portion. Head very thick, with short snout ; eye very small, about one-seventh of the
length of the head, and one-half of that of the snout. Posterior margin of the

REPORT ON THE DEEP-SEA FISHES.

29

prseoperculum subvertical; lower jaw slightly prominent; cleft of the mouth rather
oblique; the maxillary reaches to below the anterior portion of the eye, and is moderately
dilated behind. Origin of the dorsal fin somewhat nearer to the extremity of the snout
than to the caudal fin, and behind the base of the ventrals, which is below that of the
pectorals; the last dorsal ray is above the middle of the anal. Pectoral fin lone, ex-
tending at least to the middle of the anal fin. The scales, which are lost, appear to
have been of unusually large size; there were, perhaps, not more than eighteen along
the lateral line. Black.

Habitat. — South of New Guinea.

Ofi'the Arrou Islands, Station 191 ; depth, 800 fathoms. One specimen, 3 inches long.

Melamphaes robustus, n. sp.

D. 13(?x\). A. i.

V. ^.

L. lat. 33.

The height of the body is two-sevenths of the total length (without caudal); the
length of the head a little less than two-fifths ; the least depth of the tail is two-fifths
of its free portion. Head thick, with the usual muciferous cavities; snout short ; eye
very small, about one-eighth of the length of the head and one-half of that of the snout.
Posterior margin of the prseoperculum subvertical; lower jaw slightly prominent; cleft
of the mouth rather oblique, wide, extending beyond the eye. Maxillary dilated behind.
Origin of the dorsal fin midway between the end of the snout and the root of the caudal,
somewhat behind the base of the ventrals, which are distinctly thoracic. The last dorsal
ray is opposite to the first of the anal. Upper pectoral rays elongate and reaching to

the vent; ventrals rather short. Uniform black.

Millims.
Total length, ........ 53

Depth of the body,

Length of the head.
Diameter of the orbit, .
Length of the caudal fin.

m
n'

2

8

Habitat. — Mid- Atlantic, south-west of Sierra Leone, Station 106 ; depth, 1850
fathoms. One specimen which has lost its scales, and has most of the fin-rays broken.

Melamphaes heanii, Gthr.

Plectromus crassiceps, Bean, Proc. U.S. Nat. Mus., 1885, p. 73.

D. T^^.. A. ^,. V. 8. P. 15. L. lat. ca. 25.

ll-)2-

The length of the head is one-third, the depth of the body two-sevenths of the
total length, without caudal. The eye is about two-ninths of the length of the head.

30 THE VOYAGE OF H.M.S. CHALLENGER.

The pectoral is as long as the head, and more than twice as long as the ventral, which
does not quite reach to the vent. Black.

Habitat. — Four specimens are known to have been obtained in the Central Atlantic : —
at a depthof 855 fathoms, in lat. 41° 40' K, long. 65° 35'; at a depth of 1022 fathoms,
in lat. 39° 44' N., long. 71° 4'; at a depth of 1497 fathoms, in lat. 37° 41' N.,long. 73° 3';
and one at a depth of 2949 fathoms.

Melamphaes suhorhitalis.

Pledromus suborbitalis, Gill, Proc. U.S. Nat. Mus., 1884, vol. vi. p. 258.

D3 A 1

Elongate like the two preceding species. Black.

Habitat. — One specimen is known from the Central Atlantic, obtained by the United
States S.S. " Albatross," at a depth of 1735 fathoms, in lat. 38° 52' N., long. 69° 24'.

Malacosarcus, n. gen.

Head large and thick, with the bones very thin, and with wide and deep muciferous
cavities; also the canal along the lateral line is much distended. Cleft of the mouth
wide, obliquely descending backwards, with the jaws nearly equal in front. A narrow
band of villiform teeth in both jaws; palate toothless. Eight branchiostegals, pseudo-
branchiae present. The edges of the pra^operculum and the lower edge of the mandible
with minute and distant spines. Scales extremely thin, not sculptured, deciduous,
irregular, and of moderate size. One dorsal; caudal emarginate, with broad basal fold
above and below; anal spines very feeble. Ventrals small, five-rayed, inserted at some
distance behind the pectorals. Gills four; gill- laminae short; gill-rakers long, needle-
shaped.

Although this fish is only a degraded form of Melamphaes, it will be better to make
it the type of a distinct genus, as otherwise the generic definition of Melamphaes would
lose much in precision.

Malacosarcus macrostoma.

Scopelus macrostoma, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 186.

B. 8. D. 13. A. 13. P. 10. V. 5.

The body is highest where it joins the head, and rather rapidly becomes lower
towards the tail ; its greatest depth is rather more than one-fourth of the total
length (without caudal), the length of the head one-third. Head thick, with the snout

EEPORT ON THE DEEP-SEA FISHES. 31

of moderate length, obtuse, and with the jaws equal in front ; eye small, not quite
one-sixth of the length of the head, and two-thirds of that of the snout. Posterior
margin of the prseoperculum oblique, rounded. Operculum narrow, membranaceous.
Cleft of the mouth oblique, very wide, the maxillary reaching far behind the eye
to the mandibulary joint. It is obliquely ddated behind. Origin of the dorsal fin
but little nearer to the extremity of the snout than to the root of the caudal, and not
much in advance of the vent ; its last ray opposite to the last ray of the anal. Pectoral
with narrow base, rather small, scarcely extending to the origin of the dorsal. Ventral
very small, its root equidistant from the vent and the vertical from the base of the
pectoral ; the caudal rays extend a considerable distance forward on the upper as well as
lower side of the tail, and are enclosed within the remains of the embryonic vertical fin.
Gdl-rakers of the first branchial arch twenty-seven in number, the longest nearly twice
as long as the eye. Transparent ; with the sides of the head and the abdomen black.

Habitat. — Mid-Pacific, Station 271; depth, 2425 fathoms. One specimen, 3^ inches
long.

Near the Low Archipelago, Station 276 ; depth, 2350 fathoms. One specimen,
3^ inches long (in bad condition).

The specimen which has served for the description is not in a good state of preserva-
tion ; in fact, the structure of the bones, integuments, and muscles of the fish is so soft
that we can scarcely hope ever to obtain a perfect animal. The rays of the vertical fins
are also much broken, so that it is impossible to distinguish in the dorsal fin between
spines and rays. The soft condition of the parts, the embryonic condition of the caudal,
the want of development of the ventral fins, the absence of colour, the short branchial
lamina;, &c., indicate that this fish inhabits actually the great depth as recorded in the
journal of the Challenger.

Stephanoberyx.
Stephanoheryx, Gill, Proc. U.S. Nat. Mus., 1884, vol vL p. 258.

This genus is very imperfectly known at present, and said to be closely allied to
Melamphaes, but with cycloid scales which are armed about the centre with one or two
erect spines, and with only five soft rays in the ventral fin.

Stephanoheryx monse (D. 14. A. 13. P. 10), is named from a single small
specimen, obtained by the United States S.S. "Albatross," in the Atlantic, lat.
41° 9' N., long. 65° 55', at a depth of 1253 fathoms.

Beryx, Cuv.

Body compressed and deep, covered with ctenoid scales which are regularly arranged ;
abdomen compressed, trenchant, but without enlarged dermal scutes. Head rather large,

32 THE VOYAGE OF H.M.S. CHALLENGEE.

with thin bones and high ridges, between which large muciferous cavities are lodged.
Mouth very wide and oblique ; villiform teeth in the jaws, on the vomer and palatine
bones. Eye very large. Branchiostegals from seven to ten, gill-oi^enings very wide.
Prgeoperculum without spine. One dorsal fin with a few spines in front ; ventrals with
seven and more rays; pectoral asymmetrical; anal with four spines; caudal deeply
forked, with the upper and lower rudimentary rays transformed into spines. Air-bladder
simple ; pyloric appendages from twenty to thirty.

Of the five species known of this genus two only are known to descend to such a depth
as to justify their admission into the deep-sea fauna. The other species (which belong to
the Australian fauna) seem to live habitually in shallower water, and not far from the
coast, where they are captured not unfrequently by the ordinary means. The two deep-sea
species are Beryx decadactylus and Beryx splendens ; they were discovered first in the
sea off Madeira, and more recently in the sea off" Japan. Lowe says that " the latter
species, the ' Alfonsin a casta cumprida ' of the Madeiran fisherman, begins to be met
with of small size at the depth of 150 or 200 fathoms, but is scarcely taken in full size
and plenty except with its congener, Beryx decadactylus, the ' Alfonsin a casta larga,'
at the depth of from 300 to 400 fathoms, and from one to two leagues from shore." The
Challenger Expedition obtained specimens of Beryx decadactylus only, off" Inosima, at a
depth of 345 fathoms, whilst we are indebted to H. Batson Joyner, Esq., for specimens
of Beryx splendens, which he obtained during his residence at Tokio.

Young specimens have been found in the open sea. A specimen, described by Cuvier
and Valenciennes under the name of Beryx delphini, was taken from the stomach of a
Coryphsena in the Western Indian Ocean, in lat. 82° S. and long. 51° E.

Eemains of extinct species of Beryx are found in Cretaceous formations, but not all
the species described as such belong to this genus or even family. The skeleton of Beryx
decadactylus, of which a figure is given on PI. VI., well illustrates the family charac-
teristics.

On the whole the bones of the skeleton are solid and firmly built, but some of the
bones of the head are dilated into thin lamellar ridges, between which the muciferous
channels and cavities are lodged. This is particularly the case with the bones forming
the roof of the skull, the infraorbital ring, and the lower part of the mandible. The
canal running along the praeopercular limbs is much less deeply excavated. The basal
portion of the cranial cavity is comparatively short and deep, very much swollen to lodge
the organ of hearing and especially a pair of very large otoliths. The bones forming this
part of the skull are thin and perforated by an oblong opening between the alisphenoid
and basisphenoid, as in Myripristis}

The vertebral column consists of eleven abdominal and thirteen caudal vertebrae.
The five anterior neural spines are remarkably stout and broad to support the anterior

1 Cat. Fish., vol. i. p. 23.

REPORT ON THE DEEP-SEA FISHES. 33

spinous part of tlie dorsal tiu. The three anterior interneurals have no dii-ect connection
with the dorsal fin, but terminate in the soft parts of the back. The remaining inter-
neurals with which the dorsal rays articulate are feeljle, one or two of the anterior and two
or three of the posterior corresponding to the several neural spines. The haemal spines
of the caudal vertebrae are longer and stronger than the opposite processes. The haemal
of the eleventh vertebra, which forms the boundary between the abdominal cavity and the
muscles of the tail, is exceedingly strong and long and anchylosed to the first interhsemal,
the distal extremity of which is dilated into a vertical lamella. The remaining inter-
hsemals are feeble, three being lodged between each pair of hsemaLs. There are not less
than eight interhsemals abutting upon the first haemal. The pubic bones are peculiarly
shaped, somewhat resembling those of Myriprisiis ; they are much higher in the vertical
line than broad in the horizontal ; anteriorly they are produced into a very long styliform
process, stretching across the whole width of the shoulder-girdle to its front margin.
Posteriorly they form a trihedral cavity with the entrance from beneath, and with a
longitudinal ridge on the outer and inner surface.

Beryx decadactylus.

Beryx decadactylus, Cuv. Val., iii. p. 222.

„ „ Lowe, Fish. Madeii-a, p. 53.

„ „ Steintlacliner, Denkschr. d. k. Akad. d. Wiss. Wieii, xlvii. p. 220.

„ splendeng, Lowe, Cambr. Phil. Trans., vol. vi. tab. 3 (no descript.).
„ hm-ealis, Diib. and Kor., K. Svensk. Vetensk. Akad. Haudl., 1844, p. 33, pi. ii.
Collett, Vidensk. Selsk. Forliandl. Christ., 1884, No. 1, pi. i. (young).
„ „ Lilljeborg, Sverig. och Norg. Fisk., p. 76.

B. 8 (7). D. j^. A. ^^. V. 9-^. • L. lat. 64-65. L. transv. 34-35.
The depth of the body exceeds the length of the head, and is two-fifths of the total
length.

Habitat.— OS Inosima, Japan, Station 232 ; depth, 345 fathoms. Two specimens,

14 and 12 inches long.
Beryx splendens.

Beryx splendens, Lowe, Proc. Zool. Soc. Lond., 1833, p. 142; Cambr. Phil. Trans., vol. vi. p. 197.
(not fig.); Fish. :Madeii-a, p. 47, pi. viii.
Giinth., Ann. and Mag. Xat. Hist., 1878, vol i. p. 485.
Hilgendorf, Sitzungsber. d. Gesellsch. naturf. Freunde, Berlin, 1879, p. 78.
„ „ Steindachner, lor. cif., p. 221.

B. 8 (9). I). ^3^5- A. ^^. V. lo^ra. L. lat. 71-76. L. transv. i^.

The depth of the body is etiual to the length of the head, and one-third or one-fourth

of the total.

T 11 5

(ZOOL. CHALL. EXP. PART LYII. — 188G.)

34 THE VOYAGE OF H.M.S. CHALLENGER.

Polymixia, Lowe.

The fishes of this genus have about the same bathymetrieal and horizontal distribu-
tion as Beryx.

Polymixia nohilis (PI. I. fig. B).

Polymixia nolilia, Lowe, Cambr. PhiL Trans., 1838, vol. vi. p. 198.

„ „ Giinth., Fish., i. p. 17.

Nemohrama webii, Valenc. in Webb and Berthel. Iclitbyol. lies Canar., p. 41, pi. viii.
Polymixia lowei, Giinth., Fisb., i. p. 17.

„ „ Poey, Eeport Cub., ii. p. 158.

Dinemus venustus, Poey, Mem. Cub., 18G0, pp. 161, 352, pi. xiv. fig. 1.
Polymixia japonica, Giinth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 436.

„ „ Steindachner, Denkscbr. d. k. Akad. d. Wiss. Wien, 1883, xlvii. p. 261,

tab. iv. fig. 2 (barbels ?).

Specimens of this genus have been obtained at rare intervals in various parts of the
tropical and subtropical Atlantic, namely, near Madeira, the Canary Islands, St. Helena
and Cuba. The Challenger Expedition brought home specimens from the Sea of Japan,
where they were captured ofi" Inosima, at a depth of 345 fathoms ; and quite recently I
have received a specimen from the Mauritius, my correspondent informing me that it was
the first specimen of its kind which the fishermen remembered to have seen. This deep-
sea form has therefore a wide geographical range, although it probably does not descend
to very great depth or extend beyond the tropical or subtropical zones. From comparison
of all these materials I have also convinced myself that the difi"erences on which I for-
merly separated individuals from distant localities are without specific importance. The
specimen figured is one of the Challenger specimens from Inosima.

Habitat. — Ofli" Inosima, Japan, Station 232 ; depth, 345 fathoms. Three specimens,
6^ and 7^ inches long.

Poromitra.

Poromitra, Goode and Bean, Bull. Mus. Comp. ZoiJl., vol. x. No. 5, 1883, p. 214.

Body short, compressed, scopeliform, covered wdth thin cycloid scales. Head 'very
large, nearly half the entire length of the fish to base of caudal, with scales upon cheeks,
suboperculum, and probably elsewhere. No barbel. Mouth very large, the lower jaw
projecting. Margin of upper jaw composed of a short intermaxillary and a long maxiUary.
Teeth cardiform, numerous, very small on the intermaxillaries and mandibles. None
discovered on maxillaries, palatines or vomer. Opercular apparatus complete. Ventrals
very small, inserted in advance of the pectoral. Dorsal fin in the middle of the body, its

REPORT ON THE DEEP-SEA FISHES. 35

origin not far liehind that of the ventrals, the spinous and soft portions subequal in
length. Anal much shorter than dorsal, its middle under the end of the dorsal or nearly
so. Pseudobranchise present. Gill-openings very wide, separate.

Poromitra capito.

Pororiiitra capito, Goode and Bean, loc. cit., p. 215.

D. ^. A. 9. V. 7 or 8. P. 12. L. lat. ca. 24. L. transv. ca. 10.

Of this fish two specimens only, 1^ inches long, and in a dilapidated condition, were
obtained in 1632 fjxthoms during the cruise of the U.S. steamer "Blake" oft' the
American coast, in lat. 34° N. and long. 75° W.

Myriimstis, Cuv.

Myripristis haianus.

Myripristis Timanus, Giinth., Report on the Shore Fishes, Zool. Chall. Exp., part vi. p. 39.
Habitat.— OS the Ki Islands, Station 192 ; depth, 140 fathoms.

Family Teichiueid^.
Nealotiis, Johnson.

Body elongate, much compressed, incompletely covered with delicate scales. Small
teeth in the jaws and on the palatine bones ; none on the vomer. First dorsal composed
of about twenty spines extending on to the second ; finlets behind the dorsal and anal ;
a dagger-shaped spine behind the vent. Caudal fin well developed. Ventrals reduced
to a spine each. No keel on the tail.

Nealotiis tripes.

Nealotus tripes, Johnson, Proc. Zool. See. LonJ., 1865, p. 434.

D. 21 I 19-fII. A. 18-hII. P. 13. V. 1.

This fish was known from a single example,' 10 inches long, obtained at Madeiiva in
the month of December, and has been fuUy described by Johnson. The Challenger

> Mr. Johnson says (he. cit, p. 435) that this specimen has heen deposited in the British Museiuu. Such was
undouhtedlv his intention at the time when he .vrote his description, as before ami afterwards he most liberally
presented his ichthyological treasures to the National Institution. But this specimen was never received, and from
later inquiries it would appear that this valuable type is lost.

36 THE VOYAGE OF H.M.S. CHALLENGER.

collection contains a very young specimen, only 33 mm. long, wliich agrees so well with
Johnson's description that it no doubt Ijelongs to the same species. Only the dagger-
shaped postanal spine is shorter than the ventral spines, and also the separation of
distinct finlets cannot be clearly made out, as might be expected in so young an example.
It was brought up in the dredge at Station 40, in lat. 34° 51' N., long. 68° 30' W., where
the dredge had reached a depth of 2675 fathoms. However, no part of the organisation
of these Trichiuroids indicates that they descend to so great a depth, whilst, on the other
hand, young Trichiuroids are not rarely found near the surface. It is, therefore, much
more probable that this small fish entered the dredge shortly before it came to the
surface.

Aiihanopus, Lowe.

Body much elongate, band-like, scaleless; head long, pointed; cleft of the mouth
very wide, the jaws being armed with strong lanceolate teeth disposed in a single series
and in a common alveolar grove; no teeth on the palate. Eye very large. The whole of
the back is occupied by a dorsal fin which is divided into two subequal divisions. Anal
spines numerous, very feeble; a strong dagger-shaped spine behind the vent. Caudal fin
well developed, deeply cleft; pectoral fins of moderate length, rounded; ventral fins
absent. Seven branchiostegals ; air-bladder present. Pyloric appendages in small
number.

A2')hanopus carho (PI. VII. fig. A).

Aphanopus carho, Lowe, Proc. Zool. Soc. Lond., 1839, p. 79.
„ ,, Giintli., Fish., vol. iL p. 343.

„ „ Capello, Journ. Sci. Acad. Lisb., vol. i., t. iv. fig. 4.

We have no information as to the exact depth at which this fish lives, but there is no
doubt that it belongs to the deep-sea fauna, as it is caught, and only very rarely, on the
longest lines of the Madeiran fishermen; oflfthe Portuguese coast it is similarly obtained on
the tackle used by the Portuguese fishermen for the capture of deep-sea sharks. The large
eye, the black colour of the body, the thinness of the bones of the head and of the :
vertebrae are additional evidence of the bathybial habits of the iish. >

The length of the species is from 4 to 5 feet.

Nesiarchus, Johnson.

Body elongate, compressed, covered with small scales. Eye of moderate size.
Several strong fangs in the jaws; palate toothless. First dorsal fin with about twenty
spines, separate from the second. No detached finlets. Ventrals small, thoracic. Caudal
fin present. A dagger-shaped spine behind the vent.

REPOET ON THE DEEP-SEA FISHES.

37

Nesiarchus nasutus.

Nedardius nasutus, Johnson, Proc. Zool. Soc. Lond. 1862, p. 173, pi. 22.

Prometheus paradoxus, Capello, Journ. Sc. Acad. Lisb., voL iii. p. 260, pi. iv. fig. 5 ; and vol.
VL p. 1.54.

This is the ouly species of the genus ; it is a large iish, known from a few speci-
mens only which have been found in the sea off Madeira and the Portuguese coast. It
is without doubt a deep-sea fish, which comes to the surface only by accident.

Lepidopus, Gouau.

Body much elongate, band-like, scaleless ; head long and pointed ; cleft of the mouth
wide, the jaws being armed with strong lanceolate teeth in a single series ; a series of
small teeth on the palatine bones. Eyes large. The whcjie of the l)ack is occupied by
a single dorsal fin ; anal spines numerous, but the majority are rudimentary or may
disappear entirely ; no postanal spine ; caudal fin small. Ventral fins absent or
rudimentary. Eight branchiostegals ; air-bladder present. Pyloric appendages rather
numerous.

Lepidopus caudatus (Euphrasen).

The Scabbard-fish or Frost-fish of New Zealand is probably an
inhabitant of moderate depths, although no positive evidence has been
forthcoming as to its vertical distribution. It is rather common in
the Mediterranean and warmer parts of the Atlantic, at the Cape of
Good Hope, in the seas around Tasmania and New Zealand, and on
the coast of California. Lendenfeld has observed that the Frost-fish
periodically appears on the coast of New Zealand in numbers, evidently
rising from the depths which it inhabits in order to deposit its spawn.'

The skeleton has been described in the Catalogue of Fishes, vol. ii.
p. 345, and the annexed figure represents the abdominal surface of the
pelvic bones with the rudimentary scale-like ventral fins, twice the
natural size.

Fio. 2.— Pel vie bones of
Lepidopus caudatxis.

Lepidopus tenuis (PL VII. fig. B).

LepidoiMS tenuis, Giinth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 437.

D. 126. A. 71.

This species is distinguished at the first glance by the extraordinary slenderness
of the body, the depth of which is not much more than one-fourth of the length

J Zool. Anzeiger, 1883, p. 559.

38 THE VOYAGE OF H.M.S. CHALLENGER.

of tlie head; the latter is two-fifths of the length of the trunk, and one-seventh of the
total. The lateral teeth are comparatively stronger and fewer in number than in
Lejndojms caudatus. The terminal portion of the tail becomes so slender that its entire
depth is occupied by the mucous canal of the lateral line, which is very wide. Caudal
fin very small. The anterior anal rays are not free, but hidden below the skin.
Uniform silvery.

Habitat. — Ofi" Inosima, Japan, Station 232 ; depth, 345 fathoms. One specimen,
24 inches long.

The above diagnosis requires scarcely any addition. The two pairs of large teeth
which occupy the front of the upper jaw in Lepidopus caudatus are present also in this
species, but happen to be broken ofi" near the base in the present specimen. None of the
teeth show a trace of being barbed near the apex. Gill-rakers minute and remote from
each other. The inside of the mouth and pharynx is black, indicating, in conjunction
with the wide lateral line, delicate structure of the skin, fin-rays and membranes, the
bathybial habits of the fish. On the other hand, its eye is comparatively smaller than in
Lepidopus caudatus, being contained seven and a half times in ,the length of the head,
and three and a half times in that of the snout.

Lepidopus elongatus.

Lepidopus elongahis, Clarke, Trans. New Zeal. Inst., vol. xi., 1879, p. 294, pi. xiv.
Benthodesmus elongatus, Goode and Bean, Proc. U.S. Nat. Mus., vol. iv., 1882, js. 379.

D. 154-155. A. 25 (Clarke). 100 (G. and B.).

This fish is so closely allied to Lepidopus tenuis that I should have referred it to
that species, but for the circumstance that both the descriptions agree in assigning to
it twenty-eight or twenty-nine more dorsal rays than are found in the Japanese
specimen. Also the dermal elements of the anal fin seem to be more numerous in
Lepidopus elongatus than in Lepidopus tenuis. Clarke represents the caudal fin as
distinctly forked, and so it may have been in the specimen of Lepidopus tenuis, in
which this fin is much mutilated. He also counted of the anal rays those only which
were connected by membrane, and it is quite possible that at an earlier age a similar
connection existed between the posterior rays in Lepidopus tenuis.

The discoverer of this fish found eight or ten specimens washed ashore on the
Hokitika Beach on October 12, 1874; the largest was 27-g inches long. The example
described by the North American ichthyologists was taken from the stomach of a Halibut
caught in 80 fathoms on the Grand Bank of Newfoundland.

REPORT ON THE DEEP-SEA FISHES. 39

Trichiurus, L.
Trichiurus lepturus, L.

Trichiurus lepturus, Giinth., Report ou the Shore Fishes, Zool. Chall. Exp., part vi. p. 6G.
The Silvery Hairtail is a common surface-fish in the warmer parts of the Atlantic, the
Indian Archipelago, in the Chinese and Japanese Seas, and in New Zealand. The
Challenger Expedition obtained it off Inosima in 345 fathoms.

Euoxymetopon, Poey.

Body much elongate, band-shaped ; head with the supraocular portion compressed
into a trenchant edge, and the upper profile abruptly descending towards the end of the
snout ; eye of moderate size, much below the upper profile. Cleft of the mouth wide ;
teeth lanceolate, in single rows, with larger ones in front ; a series of small teeth on the
palatines. Fins as in Lepidopus.

Euoxymetopon tsenicitus.

Euoxymetopon txniatu^, Poey, Proo. Acad. Nat. Sci. Philad., 1863, p. 228; An. Soo. Espan.

Hist. Nat., 1873, p. 77, lam. 5.

B. 7. D. 87. A. .r-Hl9. P. 12.

The ventral fins are reduced to a pair of flat scales ; the dorsal commences above the
eye, the diameter of which is about one-sixth of the length of the head. Body with reddisli
longitudinal bands.

Of this fish only one specimen ' is known to exist in collections, which was obtained
by Professor Poey at Havannah, and is five feet long. The reference of this fish to the
bathybial fauna is merely inferential at present, as nothing is known of the particular
circumstances under which the typical specimen was captured. But it is most improbable
that, if it came as frequently to the surface as Lepidopus caudatus, it should have escaped
so long the observation of an indefatigable collector like Professor Poey.

Euoxymetopon p>oeyi, n. sp. (PI. XLIII.).

A fish which I have received from the Mauritius, whilst this Keport is passing through
the press, agrees in all the principal characteristics so completely with the Cuban fish, that

1 After having examined the original account given by Hoy in Tram. Linn. Soc. Land., vol. xi., 1815 p. 210, of
two supposed specimens of Trichiur>is lepturus from the Moray Firth, I concur with the view expressed by Fleming
(Ann. and Mag. Nat. Hist., Yol. iv., 1831, p. 219) that the specimen captured in 1810 wa., a Trachypterus, m^ijith
Mr. F. Day (Fish, of Great Britain and Ireland, p. 222), who refers the second which was thrown ashore in 1812, to a
species of Regalecm.

40 THE VOYAGE OF H.M.S. CHALLENGER.

it is with great hesitation that I describe it as a second species, attaching to it the name
of the discoverer of the genus. There are two points in which our specimen apparently
differs from the Cuban specimen. First, it possesses an enormously large first? dorsal
spine; but then this spine is but loosely articulated with the interneural, and it is quite
possible that it may have been lost, during or after the life of the fish, in Professor
Poey's specimen. Secondly, the original description in the Proceedings of the Phila-
delphia Academy mentions a postanal spine at the commencement of the anal fin,
which, however, is afterwards explained by Professor Poey to be hidden under the skin,
and therefore not apparent in his figure. Neither should I have taken any notice of
this spine in our specimen ; it is entirely covered by skin, and consists of coalesced and
flattened interhaemal elements, and cannot be properly called a spine. But in our speci-
men, a single oval scale slightly bent along the middle occupies the place at a short
distance behind the vent ; this scale is quite similar to the scales representing the ventral
fins, but single, and of about the same size.

The specimen is a dry skin, 78 inches long, and in a good state of preserva-
tion; it was unknown to any of the fishermen at Port Louis, and the captor stated
that he had obtained it at a depth of 70 fathoms.

D. 93. A. a: -I- 20. P. 12.

The greatest depth of the body is below the first dorsal spine, and one-thirteenth of
the total length or even less; length of the head one-eighth of the total; orbit occupying
the middle of the depth of the head, a little nearer to the end of the snout than to the
end of the gill-cover, and one-fifth of the length of the head. Each jaw with a series
of small, flat, and triangular teeth, but the upper jaw is armed besides with three large
compressed fangs which stand inside the outer series of small teeth, and of which the
two posterior are placed more closely together, and are somewhat larger than the
anterior ; in the lower jaw the foremost pair is very little larger than the others. The
first dorsal spine is large, compressed, sword-shaped, finely ribbed, and in its mutilated
condition not much shorter than the head. The lower pectoral rays are twice as long
as the upper, and half as long as the head; vent somewhat in advance of the middle
of the total length. A large scale marks the commencement of the anal fin, the rays
of which begin to be free in the posterior third of its extent. Hind part of the tail
very slender; caudal fin deeply forked. Coloration in the present state of the specimen
uniform silvery.

I have given on PI. XLIII. a view of the anterior part of the fish of the natural size,
an outline figure, reduced in size, of the entire fish, and separate views of the pair of
ventral scales {a) and of the single postanal scale (6).

REPORT ON THE DEEP-SEA FISHES. 41

Gempylus, Cuv. Val.

Body much elongate, compressed, almost scaleless. Eye large. The first dorsal
continuous, mth thirty and more spines, and extending on to the second. Six finlets
behind the dorsal and anal; ventrals rudimentary. Several strong teeth in the jaws,
and some small ones on the posterior part of the palatine bones.

The single species known, Gempylus serpens, figured by Cuvier and Valenciennes,
on pi. ccxxi., and by myself in Fische d. Siidsee, taf. Ixviii. fig. B, has been rarely
obtained at the Canary Islands, in the Caribbean Sea, and near the Society and
Sandwich Islands. It is generally reported to be an inhabitant of great depths, but
nothing positive is known as to its vertical range.

Very young specimens are not rarely found in the open sea; their changes during
growth have been observed by Liitken.^

Family Carangid^.

Anomalops, Kner.

Body oblong, covered with small rough scales. Snout very short and convex, moutli
very wide. Eyes very large; a glandular, elongate, partly free, luminous organ occupies
a hollow of the infraorl)ital ring below the eyes. Villiform teeth in the jaws and on the
palatine bones ; vomer toothless. First dorsal short; second and anal moderately long;
caudal forked.

Anomalops palpebratus.

Spams palpebratus, Boddsert, in Pallas K Nord. Beitr., ii. p. 55, tab. iv. figs. 1-2.
Heterophil lamus kafop(ro7i, Bleek., Act. Soc. Sc. Ind. Nederl., i.; Manado en Makass., p. 42.
Anomalops grafci, Kner, Sitzungsb. Akad. Wien, 1868, Iviii. p. 294, tab. i. fig. 1.
Anomalops palpebrattis, Giinth., Fisch. d. Siidsee, p. 142, taf. xci. fig. a.

D. 5 I 15-16. A. 13. V. 1

The height of the body equals the length of the head, and is two-sevenths of the
total; the large eye is only two-fifths of the length of the head. The maxillary extends
to behind the middle of the eye. Prseoperculum finely denticulated. Nearly uniform

blackish.

Of this singular fish only six specimens are known, viz., four from Amboma and
Manado, one from the Fiji Islands, and one from the Pauraoto Archipelago. The largest
is 12 inches long. This fish lives evidently in great depths, and comes to the surface

1 K. Dansh. Vidensk SelsL Skriv., xii., 1880, p. 4r,G, tab. iii. figs. 5-8.

TUP

(ZOOI. CHALU EXP.— PART LVII.— 1883.)

42 THE VOYAGE OF H.M.S. CHALLENGER.

at night or by accident only. The peculiar organ below the eyes is without doubt of
the same nature and has the same function as similar structures on the side of the head
of other deep-sea fishes ; as in Pachystomias, it is partly free, as if it could be made to
protrude out of the pit in which it lies.

Kner places this fish in the Berycidse, from which family it is removed by the
different structure of its fins. I have not been able to examine specimens.

Family C Y T T i D ^.

Cyttus, Gthr.

The two species of this genus which were previously known — one from Madeira, the
other from the coast of South Australia — are large-eyed fishes which probably inhabit
the same depth as our John Dory {Zeus), and which on the evidence extant cannot be
included in the deep-sea fauna. The small fish, of which we here give a description,
is reported to have been taken at 400 fathoms, and diff"ers in some particulars from the
diagnosis given for the genus, which differences, however, do not seem to me to call for a
generic separation. There is nothing in its organisation which would lead one to suppose
a priori that it comes from a greater depth than its congeners.

Cyttus ahhreviatus (PI. X. fig. B).

Platystetlms abbreviatus, Hector, Trans. New Zeal. Inst., vol. vii., 1875, p. 247, tab. xi.

Cijttus abbreviatus, Hector, loc. cit, vol. ix., 1876, p. 4G5.

Aiitigonia mulleri, KJunzinger, Sitzungsb. Akad. Wien, Ixxx., 1880, p. 380, taf. v. fig. 3.

B. 6. D. 7/26. A. 2/26. P. 16. V. ^.

Eesembling the boar-fish in general appearance, the body being much compressed and
elevated. The highest point of its upper profile is the root of the first dorsal spine, the
greatest depth of the body being more than one-half of the total length, without caudal.
The lower profile is also convex, but less so than the upper. The head participates in
the general form of the body, and its length is more than two-fifths of the total, without
caudal. Peduncle of the tail very slender, much longer than deep.

The eye lies immediately below the upper profile and is large, at least as long as the
snout, and two-fifths of the length of the head. Snout pointed, with the lower jaw
projecting and the mouth obliquely directed upwards. The distal portion of the maxillary
is dilated, and terminates on its antero-inferior corner in a narrow process, which, when
the mouth is half open, projects downwards like a moustache. T"^^ cleft of the mouth
does not extend to below the eye; the mouth is very protractile, ^^ posterior inter-
maxillary processes sliding in the deeply excavated interorljital space, which is much

■ REPORT ON THE DEEP-SEA FISHES. 43

narrower than the orbit. An angular projection of the parietals above the front margin
of the orbit. Prseopercular margin gently convex; the opercular pieces very short
in the longitudinal axis of the head. The lower ridges of the mandible, prse- and sub-
operculum finely serrate. Teeth in the jaws very minute, forming extremely naiTow
bands; palate toothless.

The first dorsal spine is short, the second very strong, compressed, scythe-shaped, as
long as the orbit ; the other spines are much more feeble, and gradually decrease in
length. The rayed dorsal is only about half as high as the longest spine. The two
anal spines are separate from the soft portion, the anterior and longer being one-third
the length of the longest dorsal spine ; the soft anal fin is similar to the opposite dorsal.
Caurlal fin as long as the orbit, truncated. The pectorals are inserted below the middle
of the depth of the body, and are broad and much shorter than the ventrals. Ventrals
with a strong, straight, compressed spine, shorter than the dorsal spine, the fins extending
to the soft anal. The distance between the root of the ventrals and the anal spine
is less than that between ventrals and pectorals, the vent occupying the middle. The
projecting first interhsemal renders the short space between vent and anal trenchant,
whilst the pelvic region is rather flattened, and there exists no groove for the reception
of the ventrals.

The scales (fig. B') leave the nape of the neck and a narrow strip below the dorsal
profile naked. Those covering the side of the body are much deeper than long, the free
portion, which shows the entire margin of a cycloid scale, and only a few concentric
striae, being less deep than the radical portion, which is more deeply striated, the striae
(all of which run parallel to the hind-margin of the scale) being more numerous. Along
the base of the dorsal and anal fins a series of harder scales is firmly embedded in the
skin, each being armed with a series of small spines. The lateral line follows the dorsal
outline.

Silvery, with a blackish crescent behind the pectoral. Total length, 3 inches.

One specimen was obtained two hundred miles ofi" Cape Farewell, in 400 fathoms.
It is now in the British Museum.

Fig. B^ of PL X. represents a scale from the middle of the side, much magnified ; the
free portion being on the left, and the radical on the right hand side of the reader.

44

THE VOYAGE OF H.M.S. CHALLENGEE.

Antigonia, Lowe.

t/

Antigonia capros.

Antigonia capvs, Lowe, Proc. Zool. Soc. Lond., 1843, p. 85.

„ „ Giinth., Fish., vol. ii. p. 497.

„ „ Steindachner, Denkschr. d. k. Akad. d. Wiss. Wien, xlix., 1884, p. 187, pi. v.

Caprophonus aurora, Miill. and Trosch., Hor. ichth., iii. p. xsviii. taf. v. fig. 1.
Hypdnotus ruhescens, Sclileg., Fauu. Jap. Poiss., p. 84, pi. Ixii. fig. 2.

„ „ Giinth., Report on the Shore Fishes, Zool. Chall. Exp., part vi. p. 44.

Steindachner observes that the height of the body decreases with age relatively to
the length of the fish. This is true within the limits of more or less advanced age, but
exactly the reverse is the case when young specimens are taken into consideration, as I
have already mentioned in the Eeport on the Shore Fishes, and as will be seen from the
following table, in which the total length is given with exclusion of the caudal fin : —

a. Ki Islands,
h. Ki Islands,

c. Ki Islands,

d. Manado,

e. Japan,
/. Barbados,
g. Madeira,

Probably the proportions of the body are also subject to some slight individual varia-
tion, as is also the case with respect to the length of the third and longest dorsal spine,
which in old specimens is much shorter than the head, whilst it is comparatively more
slender and longer in some of the younger specimens. At a certain age a blackish ocular
band is visible, mth traces of a second below the commencement of the dorsal fin.
These bands are visible in specimen h, but not in a or c.

This fish is an inhabitant of moderate depths and has a wide distribution ; it is
therefore not very scarce. We have received specimens from Madeira, Barbados and
Manado ; several collectors have found it in Japan, and the Challenger obtained three
specimens near the Ki Islands, from a depth of 129 fathoms.

Total length.

Height of body

16 lines.

14 1

ines.

21 „

22

25 „

33

27 „

35

78 „

84

60 „

59

69 „

70

Diretmus.

Diretmus, Johns., Proc. Zool. Soc. I.ond., 1863, p. 403.
Discus, Campbell, Trans. New Zeal. Inst., vol. xi., 1879, p. 297.

Body much compressed, short and elevated, covered with small, coarsely spinous
scales, on which no lateral line can be traced ; abdomen prominent and keeled. Mouth

EEPORT ON THE DEEP-SEA FISHES. 45

wide, obliquely ascending, with projecting lower jaw. The jaws are armed with
a very narrow band (which, posteriorly, becomes a single series) of small fine teeth of
unequal size. The vomer and palatine bones are toothless. The maxillaries terminate
at their ujaper and inner extremity in a pair of short pointed processes, which form
peculiar fang-like projections in the inside of the mouth, in front of the vomer. Bones
of the head thin, with wide muciferous cavities, the lower limb of the prseoperculum
denticulated. Eyes very large. Dorsal long, without spinous division ; anal similar in
form and composition ; interradial membrane very fragile. Pectorals large ; ventral fins
thoracic, with more than five rays (?). Branchiostegals seven ; pseudobranchise.

To judge from external characters we may place this genus provisionally near Brama.

Diretmus argenteiis.

Diretmus argentcHs, Jolins., loc. dt., pi. xxxvi. fig. 1.
D. 27. A. 22. P. 18.

The specimen from Madeira, described in detail and well figured by Johnson, is still
the only one known. This author ascribes to it, although with doubt, ten ventral rays,
but the rays are much confused, broken, and split down to the base, so that their exact
number cannot be ascertained. The spine is enlarged into a thin scalpel-shaped lamella,
and marked with numerous oblique striae.

It is evident from the structure of the cranial bones, the immense eyes, the black
colour of the cavity of the mouth and pharynx, and also from the extreme scarcity of the
fish, that this species belongs to the deep-sea fauna.

Diretmus aureus.

Discus aureus, Campbell, loc. eit.

D. 26. A. 21. P. 17.

I should be inclined to refer this fish, which is known from four specimens, 2f inches
long, cast up on Hokitika beach (New Zealand), to the same species as the Madeii-an
specimen, but for the seeming absence of the enlarged ventral spine. This, of course,
might also be accounted for by the less advanced age of the specimens. All the other
differences as they appear in the description would probably disappear on a direct
comparison of the examples. The perforations of the interradial membrane of the dorsal
and anal fins, which Campbell regards as an extraordinary character, may also be seen in
the Madeiran type, and are due to the extremely delicate structure of the membrane.

46 THE VOYAGE OF H.M.S. CHALLENGER.

Family C o K y p H .E N i D .E.

Schedophilus, Cocco.

The species of this genus are pelagic ; young examples, at least, are frequently
captured in the surface-net in the open ocean. Some of the species, however, possess
structural characters which indicate bathybial habits, for instance, a singular want of
firmness of the tissues, especially of the bones.

Schedophilus medusophagus.

Schedophilus medusoj>har/us, Cocco in Giorn. Inuom. Mess. Ann., iii. No. 7, p. 57; Bonap. Faun.

it. Pesc. c. fig.
,, ,, Giiiith., Fish., vol. ii. p. 412 ; Fisoli. d. Siidsee, p. 149 ; Trans. Zool.

Soc. Lond., vol. xi., 1882, p. 223, pi. 47.

Adult specimens have been obtained in the Mediterranean, one on the coast of
Ireland, and another in the South-Sea near Samoa. Young examples are frequently
observed on the surface of the Mid-Atlantic.

Schedophilus lockingtonii.

Icichthys locldngtonii, Jordan and Gilbert, Proc. U.S. Nat. Mus., vol. ii., 1881, p. 305 ; and
Synopsis, jj. G21.

D. 40. A. 28. Y. 1

Lateral line composed of a hundred and twenty smooth scales. More slender than
the typical Schedoj)hilus, the depth of the body being one-fourth of the total length.
Eye one-fourth the length of the head.

One specimen, 7^ inches long, was obtained from deep water off San Francisco,
The fish is described as possessing very soft and flexible bones, and being without an
air-bladder. But I fail to find in the description characters which would warrant a generic
separation from Schedophilus, or the creation of a distinct family " Icosteida^."

Schedop)Mlus enigmaticus {Vl.'K.LlY.). a~^

Icosteus enigmaticus, Lockington, Proc. U.S. Nat. Mus., vol.iii., 1881, p.-^. -'

„ ,, Jordan and Gilbert, Synopsis, p. 620.

„ „ Steindacbner, Sitzungsb. Akad. Wiss. Wien, Ixxxvi., 1882, p. 82.

Schedophilopsis spinosus, Steindachner, loc. cit., Ixxxiii., 1881, p. 396.

B. 6. D. 52-55. A. 37-40. Y. \.

The greatest depth of the hoAj is above the vent, and one-half of the total length,
the head and caudal fin not included. The length of the head is contained four times.

EEPOE.T ON THE DEEP-SEA FISHES. 47

and one-fourth in the total, without caudal It is very broad above, the width of the
interorbital space being two-fifths of the length of the head; eye rather small, one-
seventh of the length of the head in adult specimens, but comparatively larger in young
ones. Cleft of the mouth of moderate width, the maxillary extending to below the
middle of the eye ; jaws even in front. Nostrils small, close together, nearer to the end
of the snout than to the eye. Teeth minute, in a single series. Praeoperculum with
several small spinous processes on the margin. Bones of the head generally soft and
flexible.

The upper profile rises abruptly from the interorbital space and describes a gentle
curve to the end of the dorsal fin. The anterior rays of the latter are short, but the
rays gradually increase in length backwards, those inserted on the posterior descending
part of the curve being the longest. Anal fin similar in shape to the opposite part of the
dorsal fin. Caudal fin rounded, with a semicircular base. Caudal peduncle with a
narrow fringe of the skin above and below. Pectoral broad, rounded, as long as the post-
orbital portion of the head ; ventrals much shorter, inserted immediately behind the
vertical from the base of the pectoral fin. Vent nearly in the middle of the length of
the body.

The skin is naked, groups of minute spines indicate the course of the lateral line;
also the rays of all the fins are beset with minute spines.

The gills are well developed ; the gill-rakers are thin, membranaceous, flexible papillae,
and as a broad membrane is stretched in the concavity of the arches, each l^ranchial
arch bears a series of gill-rakers inside as v,'ell as outside of the membrane. Pseudo-
branchise large, with a series of gill-rakers, similar to those of the branchial arches, along
the base.

The fish is of a very light coloration, transparent below the dorsal and abo^■e the
anal ; its upper half is marked with large blackish spots, irregular in shape, smaller on
the head and neck than on the rest of the body ; they form a series along the base of the
vertical fins, which are similarly spotted.

I have examined two specimens from California, of which one is 1 1 and the other
7 inches long.

-"O"

FamUy T r a c H i N i d.e.
Bathydraco.

Batliydraco, Giintli., Ann. and Mag. Xal. Uist., 1878, vol. ii. p. 18.

Body elongate, subcylindrical ; tail tapering and very attenuated behind; head
depressed, with the snout much -elongate, spatulate ; mouth wide, horizontal, with the
lower jaw prominent ; eyes very large, vertical, close together. Scales very small.

48

THE VOYAGE OF H.M.S, CHALLENGER.

embedded in the skin. Lateral line rather wide, continuous. One dorsal fin ; ventrals
jugular ; the lower pectoral rays branched. Teeth in the jaws in villiform bands ; none
on the vomer or the palatine bones. Opercles unarmed ; ten branchiostegals ; the gill-
membranes free from the isthmus and but slightly united in front. Air-bladder none.
Gills four ; pseudobranchi^e none ; gill-rakers short.

Bathydraco antarcticus (PI. VIII. fig. A).

Bathydraco antarcticus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 18.
D. 36. A. 31. P. 23. V. ^.

The greatest depth of the body is only one-third of the length of the head, which is
one-third of the total length (without caudal); the large eye occupies nearly the middle of
the length of the head, and is about one- fourth of its length. The entire upper surface
of the head is naked, but the cheeks and opercles are covered with small scales like the
body. The dorsal fin commences at a distance from the occiput, which is considerably
less than the distance of the occiput from the snout ; this fin is highest in front and
very low behind, terminating at some distance from the caudal fin. The origin of the anal
is opposite to the tenth dorsal ray. Caudal truncated ; pectoral fin very broad, with the
hind margin truncated and extending to the origin of the anal. Light coloured above ;
lower parts and gill-apertures black.

This genus is clearly allied to Chcenichthys; its habitat at a great depth is evidenced
by the diminished proportion of earthy matter in the bones of the skull ; by its large
eyes, wide muciferous channels, and coloration.

Habitat. — South of Heard Island, Station 152 ; depth, 1260 fathoms.

lines

V

Total length,

120

Length of head, .

37

Length of snout, .

13

Width of snout opposite nostrils,

n

Diameter of the eye.

H

Length of pectoral,

22

Length of ventral,

15

Length of caudal,

16

Distance of snout from origin of dorsal,

48

Distance of .snout from vent,

5.5

Depth of peduncle of tail,

n

Aphritis, C. V.
Aphritis gohio.

Aphritis gohio, Giinth., Report on the Shore Fishes, Zool. ChaU. Exp., pt. vi. p). 21, pl.jix.
Habitat. — Southern coasts of South America, from surface to 147 fathoms.
Near Magellan Strait, Station 307; depth, 140 fathoms. One specimen.

EEPORT ON THE DEEP-SEA FISHES. 49

Acanthaphntis, Gtbr.
One species only is known. i^ 'v^^

Acanthaphritis grandisquamis.

Acanthajjhritis grandisquamis, Giintli., Report on the Shore Fishes, Zool. Chall. Exp., pt. vi.

p. 43, pi. xviii. fig. A.

Habitat. — Ki Islands, Station 192; depth, 140 fathoms.

Champsodon, Gthr.
Champsodon vorax.

Champsodon vonij; Giiuth., Report on the Shore Fishes, ZooL Cliall. E.\p., pt. vi. pp. 43, 52,
pi. xxiii. fig. A.

Widely spread in the Chinese and Japanese Seas, off the Philippines and southwards
into the Arafura Sea. The Challenger obtained numerous specimens at depths of
115 fathoms (Station 204b), 140 fathoms (Station 192), and 152 fathoms (Admiralty
Islands).

Uranoscopus, L.
Ura n oscopus kaianus.

Uranoscopus kaianus, Gunth.,, Report on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 43,
pi. xix. fig. A.

Hahitat. — Arafura Sea, south of Papua, Station 188; depth, 28 fathoms.
. Off the Ki Islands, Station 192; depth, 140 fathoms.

Family Pediculati.

Lophius, Art.
Lophius piscatorius, L.

According to Brown Goode ^ the Sea-devil descends to a considerable depth. It was
taken off the coast of New England, a large specimen in 120, another in 142 fathoms, and
finally one, 26 cm. long, in 365 fathoms.

Lophius naresii.

Lophius naresii, Gunth., Report on the Shore Fishes, Zool. Chall. Exp., pt. vi. pp. 53, 56, pi. xxv.

All the specimens knowTi are from deep w^ater, viz., from 115 fathoms (Philippines,

Station 204b), from 150 fathoms (North of New Guinea, Station 219), and from the

Admiralty Islands.

1 Proc. U.S. Nat. Mas., vol. iii., 1881, p. 469.

(zool. chall. EXP.— part LVIL — 1886.) L'' '

50 THE VOYAGE OF H.M.S. CHALLENGER.

The Bathyhial Sea-devils which are noticed under the following genera, are
degraded forms of Lophius ; they descend to the greatest depths of the ocean. Their
bones are of an extremely light and thin texture, and frequently other parts of their
organisation, their integuments, muscles, and intestines are equally loose in texture
when the specimens are brought to the surface. In their habits they probably do not
diflfer in any degree from their surface representative, Lophius.

When the first individuals of this group were discovered, they seemed to be
sufficiently distinct from one another to justify generic separation. However, the
additions of recent years exhibit that variation in the shape of the body, head and
mouth, in the specialised dorsal spines, and in the development of dermal scutes, which
may be expected in such grotesquely formed creatures ; and future discoveries may lead
to a further reduction of genera, viz., to the union of the naked-skinned Melanocetus and
Oneirodes with Ceratias.

The number of the dorsal spines is always reduced, and at the end of the series of
these fishes only one spine remains, with a simple, very small lamella at the extremity
{Melanocetus johnsomi, Melanocetus murrayi). In other forms sometimes a second
cephalic spine, sometimes a spine on the back of the trunk, is preserved. The first
cephalic spine always retains the original function of a lure for other marine creatures,
but to render it more effective, a special luminous organ ' is sometimes developed in
connection with the filaments with which its extremity is provided [Ceratias hispinosus,
Oneirodes eschrichtii). So far as is known at present, these complicated tentacles attain
to the highest degree of development in Himantolophus and Aegseonichthys. In other
species very peculiar dermal appendages are developed, either accompanying the spine
on the back, or replacing it ; they may be paired or form a group of three, are pear-
shaped, covered with the common skin, and perforated at the top, a delicate tentacle
sometimes issuing from the foramen.

Himantolophus, Ehdt.

Body, short, thick, moderatel}^ compressed ; head very large. Ej^es rudimentary.
Mouth directed obliquely upwards, of moderate width, with projeeti)ig mandible. Jaws
armed with several series of rasp-like depressible teeth of different lengths ; palate
toothless. Skin thick, with round scutes scattered over the body. The spinous dorsal
reduced to a single filament ; the soft dorsal and anal very short. Ventrals none. Gills
two and two halves.

1 Whose function was first suggested by Liitken.

REPORT ON THE DEEP-SEA FISHES. 51

Himantoloi^hus groenlandicus.

Himantoloplius groenlandicus, EeinL., K. dansk. Vidensk. Selsk. Afhandl., 1837, p. 74.

„ „ Liitken, K. dansk. Vidensk. Selsk. Skriv., 1880, p. 320, tab. ii.

fig. 5 (end of dorsal filament).

B. (3. D. 1 I 9. P. 12.

The heirfit of the bodv is two-fifths of the total length.

A single much injured specimen, 23 inches long, was obtained off the coast of
Greenland.

Ilima n toloj^h us i •einhardti.

Himanfoloplms reinhardti, Liitken, loc. cif., p. 309, tab. i., tab. ii. figs. 1-4.
B. G. D. 1 I 5. A. 4. C. 9. P. 17.

The height of the body is three-fourths of the total length.

One specimen, 14 inches long, was likewise discovered off the coast of Greenland.
Whether some young specimens obtained in Mid-Atlantic, and referred by Liitken to this
species, belong to it or to some other species, cannot be decided from the materials at
present available.

Aegaionichthij.'^.
Aegseom'cJiiJnjts, Clarke, Trans. New Zeal. Inst., vol. x., 1878, p. 245.

Head excessively large and broad ; body short. Eyes small. Mouth exceedingly
wide and vertical. Jaws armed with bands of teeth unequal in size and depressible ;
palate toothless. Skin with scattered, large, round scutes, each ending in a spine. The
s^nnous dorsal reduced to a single tentacle ; the soft dorsal and anal very short. Ventrals
none. Pectorals well developed. Gills ?

Unfortunately nothing is known of the gills of this fish, wljidi, as regards grotesqueu ess
of form, surpasses the fishes of the preceding genus. It is evidently closely allied to
Himantohphus reinhardtii, and I therefore suppose that it possesses the same number
(jf gills. If this should prove to be the case, the question will arise whether it should be
kept as the type of a distinct genus. According to the figure Aegieonichthys would
appear to be much more depressed in shape than Himantolophus ; however, we must
remember that these flaccid deep-sea fishes may assume, or l)e made to assume, very
different appearances.

52 THE VOYAGE OF H.M.S. CHALLENGEE.

Aegeeonichthys appelii.

Aegxonichthys a2'>peUi, Clarke, loc. cit., pi. vi.

D. 5. A. 4. C. 8. P. 17.

Tlie cephalic spine consists of a tuft, one-sixth as long as the fish, with a swollen
muscular base and a hemispherical head, from which spring three or four long branched
tentacles ; the shaft is covered with minute spines. Greyish, mottled with light and
splashed with dark brown.

The hemispherical head of the cephalic spine is described as a capsular gland, the
front of which is covered with a silvery or nacreous integument, with an aperture in the
centre communicating with the interior and surrounded by a black ring. It is evidently
the same structure which I have described in Ceratias hispinosus, and adapted for the
same function. It is phosphorescent, and probably illuminates the play of the tentacles
which serve to allure other creatures.

Ceratias, Krdyer.

Pediculates without ventral fins and with two gills and a half only ; no pseudo-
branchiaj. Head very large ; body and tail short ; eyes small. JMoutli large, with the
mandible projecting. Jaws armed with a series or narrow band of depressible teeth of
various lengths. Skin with dermal scutes or spinelets. The spinous dorsal fin reduced
to one or two spines, which are generally modified into tentacles, and sometimes
provided with an accessory luminous a^jparatus. The soft dorsal and anal short.

The species may be arranged in the following order : —

I. Two cephalic spines — Ceratias (Diceratias) hispinosus.

II. One cephalic spine.

A. A second spine on the back, with lateral caruncles ; no vomerine teeth —

Ceratias [Ceratias) hoIboUi.

B. No spine on the back ; with caruncles.

1. Caruncles placed at a distance from the soft dorsal.

a. Two caruncles only; no vomerine teeth — Ceratias (Mancalias)

uranoscopus.
h. Three caruncles; vomerine teeth? — Ceratias {Typhlopsaras)

slnifeldti.

2. Caruncles placed immediately in front of the soft dorsal.

a. Terminal cephalic joint very short — Ceratias ( )

carunculatus.
h. Terminal cephalic joint long — Ceratias {Cryptopsaras) couesii.

REPORT ON THE DEEP-SEA FISHES. 53

Ceratias bispinosns, n. sp. (PL XI. fig. B).

D. 1 I 1 I 6. A. 4. C. 9. P. 14.

Similar in general appearance to Ceratias johnsonii, l>ut the whole body covered
with minute prickles, giving a velvety appearance to the skin. Tho dentition is also
very similar, but the teeth in the upper jaw are less numerous and form a single series
only. The vomerine teeth form also a transverse series, but the teeth are not implanted
on an elevated ridge as in Ceratias johnsonii, and the series is interrupted in the middle.
Eye small ; a perforated nasal tube in front of the eye close to the base of the maxillary :
each frontal bone is armed with a short conical spine situated above the eye. The upper
surface of the head is concave, and in the interorbital groove there are implanted the
two tentacles to which the anterior dorsal fin is reduced. The anterior is stout, half the
length of the head, terminating in a fleshy lentil-shaped knob, which is fringed along its
edges ; the second spine is rudimentary, situated immediately behind the first. Dorsal
and anal fins close to the caudal ; caudal half as long as the remainder of the fish,
composed of bifid rays, the rays of the other fins being simple. Base of the pectoral fin
enveloped in skin ; it is of moderate length, situated above the gill-opening. The whole
fish is brownish-black, with the exception of the vertical fins, w^hich are white.

Habitat.~OS Banda Island, Station 194a; depth, 3G0 fathoms. One specimen, 3^
inches long.

Gills two and a half. The top of the knob at the end of the dorsal tentacle encloses
a cavity which is covered by a smooth cornea-like membrane, very different from the
velvety integument of the body of the knob. The membrane is perforated on the left
side by a wide pore (fig. h).

Ceratias holboelli.

'/'
Ceratias holbuIU, Krbyer, Nat. Hist. TiJs&kr., 1874, i. p. 639; and in Gaimard, Voy. SkanJ.

Poiss., pi. ix.
Lutken, K. dansk. Vidensk. Selsk. Skriv., 1S78, .\i. p. .^SG (skeL).

D. 1 I 1 I 4. A. 4. C. 8. P. 19.

Body rather compressed, short. Mouth subvertical, of moderate width, with pro-
jecting mandible. Jaws armed with rasp-like depressible teeth of diflPerent lengths, ni
sever d series ; palatines and vomer toothless. Cephalic spine very long, as long as the
body, a short distal portion connected with the rest by a joint. A second long spine on
the back, with a dermal caruncle on each side. Skin with small scutes which are
separate from each other. Black.

Three specimens, from 18 to 28 inches long, were obtained ofi" the coast of Greenland.

54 THE VOYAGE OF H.M.S. CHALLENGER.

Ceratias uranoscopus (PL XL fig. C).

Ceratias uranoscopus, Murray, in Wyv. Thomson, The Atlantic, vol. ii. p. 67.
Mancalias uranoscoptis (Gill), Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 469.

D. 1 I 3-4. A. 4. C. 8. P. 10.

Body and head much compressed ; skin finely granuLir, with scattered minute
spiuelets of equal size. Cleft of the mouth vertical. The upper end of the maxillary
with a projecting triangular spine, pointing upwards and forwards. Small pores are
scattered over the whole body. Eye rudimentary. The first dorsal spine extends to the
end of the caudal fin, its distal portion being attached to the rest by a joint. No second
dorsal spine between the pair of claviform tentacles. Gill -opening rather nearer to the
end of the snout than to the end of the caudal fin. Uniform black.

Minute foramina or pores may be seen scattered over the body, together with extremely
fine and soft tentacles of a white colour. These tentacles are so perishable that the
slightest touch removes them, and they are preserved in our specimen only on some parts
of the body. The specimen is not well enough preserved to make out whether they
rise from the bottom or the circumference of the pore. I have noticed one, two, or
three tentacles attached to one pore. I cannot detect terminal pores on the caruncles,
although they are probably present.

Habitat. — North Atlantic, Station 89; dej)th, 2400 fathoms. One .specimen, 3^
inches long.

A much larger example (9g inches long) was obtained by the U.S. Fish Commission
on the south coast of New England, at a depth of 372 fathoms. It has not been
described, which is to be regretted, as in so large an example many points might be cleared
up which must remain obscure and uncertain in a small, indiff"erently preserved example,
like that of the Challenger Expedition.

Ceratias shu/eldti.

Typhlopsaras shufeldti (Gill) Jordan, Catal. Fish. N. Amer., p. 138.
D. 1 I 0 I 4. A. 4. C. 8. P. 4 or 5.

Trunk elongate, back rectilinear. Cephalic spine long, the basal shaft reaching the
dorsal fin, and the knob of its distal joint the caudal ; knob pear-shaped, without
tentacles. A pair of dermal caruncles, with an intermediate single one at some distance
in advance of the dorsal fin. Skin ? Vomerine teeth 1

No information is given as regards the length of the specimen, which was obtained in
the Atlantic by the U.S. Fish Commission steamer "Albatross."

REPORT ON THE DEEP-SEA FISHES. 55

Ceratias carunculatus, n. sp. (PI. XI. fig. D).

D. 1 I 0 I 4. A. 4. C. 8. P. 12.

This species is rather short, with the upper profile ol)liquely descending towards the
front as well as the caudal fin. The branchial opening is midway between the end of the
snout and the root of the caudal. Vent a little to the left of the median line of the
abdomen. Eye rudimentary. Cleft of the mouth subvertical, not of excessive width.
The skin is densely covered with minute prickles of equal size, and pores are scattered
irregularly over the trunk and tail.

The first dorsal spine or tentacle is inserted between the eyes, directed forwards, and
having suspended from a very short distal joint a comparatively large lemon-shaped
body ; this tentacle scarcely extends beyond the end of the snout. Instead of a second
dorsal spine, a soft pear-shaped caruncle is developed, which differs from the two
claviform appendages between which it is placed in size only, being about twice as large.
Each of these three caruncles has a pore at its top. The other fins do not show any
peculiarity. Uniform black.

Habitat. — South of Yeddo, Station 232 ; depth, 345 fathoms. One specimen,
1^ inch long.

The specimen is figured of twice the natural size.

A fish shortly characterised in Jordan's Catalogue of the Fishes of North America,
p. 138, is closely allied to this species, if not identical with it.

Cryptopsaras couesii (Gill). Trunk shortened, back longitudinally convex ; basal
joint of the anterior spine, concealed and procumbent ; terminal joint elongate, reaching
backwards to the dorsal tubercles ; the bulb is pyriform and surmounted by a long whitish
filament. A large intermediate globular and a pair of subpeduuculated lateral dorsal
appendages near the front of the dorsal fin. D. 4. A. 4. p. 15. The specimen was
obtained by the U.S. Fish Commission steamer "Albatross." The size is not stated.

Oneirodes, Liitken.

Head very large, body short and naked. Cleft of the mouth oblique, with depressible
teeth, unequal in size, in the jaws. A cephalic and dorsal spine. The soft dorsal and
anal fins short. Ventrals none. Gills two and a half.

56 THE VOYAGE OF H.M.S. CHALLENGER.

Oneirodes eschrichtii.

Oneirodes eschrichtii, Lutken, Oversigt K. D. Vid. Selsk. Forhandl., 1871, p. 56, tab. ii.
D. 1 I 1 I 6. A. 4. C. 8.

Body short, with convex upper profile. Cleft of the mouth rather oblique;' teeth
of moderate and unequal size, in a single series in the upper jaw; vomerine teeth.
Cephalic spine about one-fourth of the total length (without caudal), with a knob at its
extremity which (is luminous and) bears various short tentacles. A second thick and
flaccid spine on the top of the back, rather longer than the first. A short conical spine
above each eye, and another at the posterior end of the mandible. Black.

One specimen, 8 inches long, obtained ofi" the coast of Greenland, has been described
in detail by Liitken.

Melanocetus, Gtlir.

Head and body rather compressed ; head and cleft of the mouth enormous ; trunk and
tail comparatively short and small. Eyes very small. Mouth vertical, jaws armed with
rasp-like depressible teeth of different lengths ; vomer toothless or armed with similar teeth.
Skin smooth, soft, and thin. The spinous dorsal is reduced to a single filament on the
head. The soft dorsal and anal short. Ventrals none. Gills two and a half.

Two species are known : —

1 . Vomerine teeth present — M. [Melanocetus) johnsonii.

2. Vomerine teeth absent — M. (Liocetus) murrayi.

Melanocetus johnsonii.

Melanocetus johnsonii, Giinth., Proc. Zool. Soc. Lond., 1864, p. 301, pi. xxv.

„ „ Lutken, Oversigt K. D. Vid. Selsk. Forhandl, 1871, p. 74; or Ann. and

Mag. Nat. Hist., 1872, vol. ix. p. 343.

B. 6. D. 1 I 14. A. 4. C. 8. P. 18.

Vomer armed with a transverse series of teeth similar to those of the jaws. Length
of the maxillary at least one half of the total length, without caudal. Black.

One specimen only is known, 3j^^ inches long; it was obtained by Mr. Johnson at
Madeira, and had in its stomach, rolled up spirally into a ball, a Scopelus which
measured T\ inches in length, and 1 inch in depth.

1 Liitken describes it as horizontal, but it is evident from the figure that the lower jaw is turned upwards
when the mouth is shut.

EEPORT ON THE DEEP-SEA FISHES. 57

Melanocetus murrayi, n. sp. (PL XI. fig. A).

D. 1 I 13. A. 4. C. 9. P. 14.

Extremely similar to Melanocetus johnsonii, but, singularly, there is no trace of
vomerine teeth, whilst there is no distinction between the two species as regards the
dentition of the jaws. The posterior angle of the mandible projects more and forms a
saUent point. The mouth is comparatively less wide, and the maxillary considerably
shorter, being about two-fifths of the total length, without caudal, whilst it is rather
more than one-half in the Madeiran species. Eye rudimentary. One cephalic spine,
which is shorter than the maxillary. The last dorsal ray is connected by a short and
delicate membrane with the caudal fin ; most of the caudal rays are bifid, the longest
shorter than the maxillary. Pectoral fin as much developed as in Melanocetus johnsonii.
Entirely black. ^

Total length, . . . . . ' . . 44 lines.

Length of mandible, . . . . . . 14 „

Length of maxillary, . . . . . . 12 ,,

Length of caudal fin, ...... 10| ,,

Habitat. — Mid- Atlantic, Station 106; depth, 1850 fathoms. One specimen, 44 lines
long.

Mid-Atlantic, Station 348; depth, 2450 fathoms. One specimen, 13 lines long.

In the young specimen the dorsal filament is already of the same relative length as in
the old one.

Linophryne, CoUett.
This genus difiers from Melanocetus in possessing a long tentacle at the throat.

Linophryne lucifer.

Linophryne lucifer, CoUett, Proc. Zool. Soc. Lond., 1886, p. 138, pi. xv.

D. 1 I 3. A. 2. C. 9. P. 14-15.

A spinous projection above each orbit. Cephalic tentacle black, with a large ovate
bulb, the upper half of which is white; gular tentacle much longer, terminating in two
tongue-like appendages, which are furnished on the upper edge with a row of round

white papillae.

One specimen, If inch long, was found floating on the surface off Madeira, in

lat. 36° N., long. 20° W.

(zool. CHALU EXP. — PAKT LVIL — 1886.) ^"- °

58 THE VOYAGE OF H.M.S. CHALLENGER.

Chaunax, Lowe.

Head very large, depressed; cleft of the mouth wide, subvertical. Skin covered
with minute spines. Jaws and palate armed with bands of small teeth. The spinous
dorsal fin is reduced to a short spine above the snout. The soft dorsal of moderate
length, anal short ; ventrals developed. Gills two and a half ; pseudobranchise

none.

The fourth branchial arch does not bear a gill, but its integument is dilated, and
forms a broad fold aloug its convex margin. The dorsal spine with the terminal tentacle
can be entirely received into the grove behind it ; the tentacle is fleshy, double-heart-
shaped, and covered with delicate filaments of a white colour.

Chaunax pictus (PL X. fig. A).

Chaunax p ictus, Lowe, Trans. Zool. Soc. Lond., vol. iii. p. 339, pi. li.
„ Guntk, Fish., iii. p. 200.

Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 470.
,, Jimhriatus, Hilgendorf, Sitzungsb. Gesellscb. naturf. Freunde, 1879, p. 80.
,, ,, Steindacliner und Doderlein, Denksclir. d. k. Akad. d. Wiss. Wien, xlix.,

1884, p. 194.

The specimens of this fish have been obtained at very distant localities. It was first
discovered at Madeira by Mr. Lowe and subsequently by Mr. Johnson. A single specimen
forms part of the Challenger collection, and was obtained near the Fiji Islands, at Station
173, from a depth of 315 fathoms. Hilgendorf and Doderlein record its existence in
the Sea of Japan, considering the specimens to be a distinct species ( Chaunax Jimhri-
atus). Finally the U.S. steamer "Fish Hawk" obtained a single small sj)ecimen on the
south coast of New England in 192 fathoms.

All these specimens I consider to belong to one and the same species. The specimen
from the Fiji Islands differs only in the colour of the rostral tentacle and of the grove into
which it is received ; these parts are black in the Atlantic specimens, and of the ^ame
colour as the body in the Fiji Island example. The latter has, in common with the
Japanese specimen, the lower parts of the muciferous ducts fimbriated with very delicate
and short tentacles, of which only a few are to be observed in Madeiran sjjecimens. With
regard to other characters on which the Japanese species was separated, I have to observe
that seven anal rays and round yellow spots occur also in Atlantic specimens, and that
the width of the interorbital sjjace is equal to two diameters of the eye, if the soft prickly
non-transparent skin aliove the eye be taken as part of the interorbital space.

Habitat. — Off Matuku, Fiji Islands, Station 173; depth, 315 fathoms. One specimen
7f inches long.

REPORT ON THE DEEP-SEA FISHES. 59

Halleiitiea, C. V.

The well-known species from China and Japan, Halieutsea stellata, is the only
representative of this genus that was hitherto known. That a second species should be
discovered in the Atlantic, can hardly excite any surprise in those who have paid
attention to the distribution of the marine fishes of the Japanese Fauna. But we should
not have expected to find that, while the Indo-Pacific species is evidently a littoral fish,
or at least one which is readily obtained by the ordinary means of fishermen, its newly
discovered Atlantic representative is an inhabitant of a depth of more than 200 fathoms.
No special modification indicative of bathybial habits has been pointed out in the Atlantic
species.

Halieuteea senticosa.

Halieutsea senticosa, Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 467.
D. 1 I 6. A. 4. C. 8. V. 5. P. 13-15.

The width of the mouth is equal to the distance between the centres of the eyes.
Disk with a marginal series of closely set spines ; outside of the marginal spines a row of
five depressed, knife-like spines, each with a crown of three spinelets ; these two rows
coalesce on the front edge of the disk.

Five specimens, 2-|~ to 5|^ inches long, were obtained by the U.S. Fish Commission on
the south coast of New England, at depths varying from 225 to 238 fathoms.

Dihranchus, Ptrs.
Difi"ers from Halieutiea by having only two gills.

Dihranchus atlanticus.

Dibranchus a^tow^Mws, Peters, Monatsber. d. k. preuss. Akad. d. Wiss., Berlin, 1875, p. 738, c. Tab.

B. 6. D. 6-7. A. 4. C. 9. P. 10-14. Y. i. Vert. ^^.

The larger tubercles with fi'om seven to ten ridges. Brown above, whitish

below.

Four specimens, 3^ inches long, were obtained ofi" the west coast of Africa in
lat. 10° 12' N., long 17° 25' W., at a depth of 3G00 fathoms.

60 THE VOYAGE OF H.M.S. CHALLENGER.

Family C o t t i d ^.
Cottunculus, CoUett.

The first species discovered of this genus, viz., Cottunculus microps, seemed to differ
so much from Cottus, especially by its enormously developed head, that a generic
separation appeared to be well justified. To the very aberrant shape of the head there
were added some other distinctive characters, viz., the connection of the two dorsal fins
by a broad membrane, and the slight development of the spines of the gill-covers, which
do not penetrate the thick skin.

The combination of these characters is not maintained in the second species, Cottus
thomsonii, which has united dorsals and small spines, but the typical Cottoid shape of
the head and body. In fact it connects Cottunculus with Cottus, so that the former can
only be retained as a group of the latter genus, characterised by the union of the dorsal
fins and division of the vomerine teeth into two groups.

Cottunculus microps (PL IX. fig. A).

Oottuneulus microps, CoY^eit, Norges Fisk., p. 20; Forh. Vid. Selsk. Christian., 1880, p. 11;
Norsk. Nordh. Exped. Fisk., p. 18, pi. i. figs. 5-6; NytMag. f. Naturvid.,
vol. xviii., 1884, p. 53.
Strom, Norsk. Vid. Selsk. Skrift., 1880, p. 75.
„ „ Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 479; BuU. Mus. Comp.

Zobl., vol. X., 1883, p. 212.
„ „ Lilljeb., Sverig. och Norg. Fisk., p. 113.

This fish has been fully described by CoUett, who examined specimens from the
open sea, south and west of Spitzbergen, dredged at depths varying between 200 and
460 fathoms. The species occurs also on the coast of Norway at depths of from 80 to 200
fathoms. Specimens of various ages, the largest 9-| inches long, were obtained during the
exploration of the Faroe Channel by the " Knight Errant," at Stations 4, 8 and 9, at
depths varying between 307 and 608 fathoms. The species seems to be also common in
the western parts of the North Atlantic, off the coast of New England, where it was
found in depths of from 238 to 372 fathoms. Our specimens show very little variation
among themselves. The two occipital prominences are sometimes compressed and
truncated, in other specimens more or less distinctly bicuspid. In an adult male the
black bands are more clearly defined, and of a deeper colour, than in the female figured,
or in the j'oung. Also the caudal, anal and pectoral fins are black, ^\ith white
margins.

REPORT ON THE DEEP-SEA FISHES.

61

Cottunculus thomsonii (PI. IX. fig. B).

Cotttis thomsonii,, GiintL, Proo. Roy. Soc. Edin., vol. xi, 1882, p. 679.
Cottunculus torvus, Goode, Bull. Mus. Comp. Zool., vol. x., 5, 1883, p. 212.

D. /v- A. 13. P. 22.

Like the typical species of Cottunculus, tlie present has the two dorsal fins enveloped
in a common and cutaneous fold, so that the division between them can be ascertained
only by dissection. But the head is much more depressed (as in an ordinary Coitus),
and the skin is apparently quite smooth and rather loose, minute granules being scattered
over the back. The protuberances on the various bones of tlie head are arranged as in
Cottunculus microps, those of the prseoperculum slightly piercing the skin, whilst those on
the top of the head are comparatively less developed. The head is much wider than deep,
its greatest width being rather less than its length, which is contained twice and two-
thirds in the total, without caudal. The eye equals the length of the snout, and is a
little less than one-fourth of that of the head. The bony portion of the interorbital space
is flat, less wide than the orbit ; and the quadrangular space enclosed by lines connecting
the four projections on the top of the head is nearly twice as long as broad.

Mouth wide, with projecting lower jaw, and with the maxillary not quite reaching to
below the middle of the eye. Vomerine teeth separated in the middle, each half forming
an elongate oval patch. Gill-membrane confluent with the isthmus opposite to the
lowermost pectoral ray.

The dorsal fin commences above the gill-opening, and is rather low in its anterior
portion ; the soft rays are more distinct externally than the spinous, and much longer,
this part of the fin being about as high as the body underneath is deep. The anal fin is
much lower and commences at some distance behind the vent. Caudal fin narrow at the
base, half as long as the head, subtruncated, with rounded corners. Pectorals extending
nearly to the origin of the anal ; ventrals small and not reaching to the vent.

The colour is now of that dirty whitish tint into which the pink hue of many fishes
changes after death ; and it is probable that this species is red during life ; the fins have
a greyish shade.

Total length, ....

86 lines

Length of head, ....

26 „

Distance of snout from vent,

34 „

Distance of snout from anal fin, .

42 „

Length of caudal fin.

13| „

Length of ventral fin,

8J „

Habitat.— h\mQ Channel, Station 4 "Knight Errant," August 10, 1880; depth, 535
fathoms. One specimen, 7\ inches long.

62 THE VOYAGE OF H.M.S. CHALLENGER.

Cottus, Art.

Coitus hathyhms (PL X. fig. C).

D. 5 I 10. A. 7. P. 17. V. 3.

The iDrseoperculum is very strongly armed ; there are two spines arising from the
same root at the angle, one in front of the other, the posterior being longer than the
eye ; three other shorter spines along the lower edge of the prseoperculum ; operculum
with a small spine at its antero-inferior angle. A pair of spines on the occiput behind a
deep depression occupying nearly the whole of the vertex. Eyes longer than the snout,
close together. Minute teeth on the vomer, but none on the palatine bones. Tail much
attenuated. Pectoral fin extending beyond the origin of the anal ; ventrals not reaching
the vent. Second dorsal fin higher than first ; length of the caudal two-fifths of that of
the body (without head). Muciferous system much developed, opening by wide pores
along the lower jaw, the prseoperculum, the infraorbital ring and the lateral line.
Grepsh-brown ; throat and all the fins black.

Habitat. — South of Yeddo, Japan, Station 235 ; depth, 565 fathoms. One specimen,
2^ inches long.

It may appear matter for surprise to find a species of Cottus at so great a depth as
560 fathoms, and at first it did not seem to me improbable that the specimen
accidentally entered the mouth of the dredge whdst it was near the surface. However,
on further consideration these doubts disappeared, as it is not very likely that a fish
living habitually at the bottom, as a Cottus must do, should be found floating fai-
from land ; moreover, the muciferous system is developed to an extraordinary degree,
much more so than in the littoral species of the genus.

Centridermichthys, Richards.
Centridermichthys uncinatus.

Cottus uncinatus, Remh., Vid. Selsk. Natur. och Math. Afhandl., 18.33, p. xliv.

„ bicornis, Reinh., loc. cit, viii. p. Ixxv.
Centridermichthys uncinatus (Giinth.), CoUett, Norsk. Nordh. Exped., Fisk., p. 29, tab. i. fig. 7;

Forh. Vid. Selsk. Christian., 1880, p. 14; Nyt Mag. f. Naturvid.,
xviii., 1884, p. 54.
„ „ Ltitken, Kara-Havets Fisk. va. Dijmphna-Togtet., p. 124.

,1 ,, Lilljeb., Sverig. och Norg. Fisk., p. 161.

An Arctic littoral species, more or less common in the sea between Greenland,
Spitzbergen, Nova Zembla, and Norway, extending in the western part of its range
southwards to the coast of New England. The Norwegian North Atlantic expedition

REPOET ON THE DEEP-SEA FISHES. 63

has obtained specimens down to 223 fathoms (off Bear Island), and, therefore, the
species is included in this Eeport. As bathybial characters, the width of the pores of the
muciferous system and the relatively large eye may be mentioned.

/^ Icelus, Kroy.

Icelus hamatns.

Icelus hamatus, Kroy., Nat. Hist. Tidsskr., 1844, i. p. 253.

„ „ Collett, Norges Fisk., p. 35 ; Forh. Vid. Selsk. Christian., 1880, p. 14; Norsk.

Nordh. Exped. Fisk., p. 34, tab. i. fig. 8 ; Nyt Mag. f. Naturvid., xviii., 1884,
p. 50.
„ „ Liitken, Kara-Havets Fisk. in Dijmplina-Togtet., p. 123.

„ ,, Lilljeb., Sverig. och Norg. Fisk., p. 164.

Strom, Norsk. Vid. Selsk. Skrift., 1884, p. 18.
Icelus furciger, Malm, Fcirh. Skand. Naturf. 9 Mote., 1865, p. 410.

This common Arctic species is found at small depths ; of late years it has been
frequently found on the Norwegian Coast in 50-250 fathoms. Liitken examined
numerous examples from 46 to 106 fathoms, obtained in the Kara Sea.

Triglops, Reinhardt.

Triglops pingelii.

Triglops pingelii, Eeinli., Vid. Selsk. Natur. och. MatL Afhandl., 1838, pp. 114, 118.
„ „ Giinth., Proc. Zool. Soc. Lond., 1877, p. 475.

„ „ Collett, Norges Fisk., p. 36; Norsk. Nordh. Exped. Fisk., p. 38, pi. i. figs. 9, 10.

„ „ Lilljeb., Sverig. och Norg. Fisk., p. 168.

„ pleurostictus, Cope, Proc. Acad. Nat. Sci. Philad., 1865, p. 81.

An Arctic species, not very common near the coast-lines of Greenland, Nova Zcmbia,
Norway, and extending in the West Atlantic southwards to the latitudes of New
England. It prefers water of about 20 fathoms, but descends to 263 fathoms.

Trigla, Art.

Trigki leptacanthus.

Trigla leptacanthus, Gunth., Eeport on the Shore Fishes, Zool. Chall. Exp., part vi. p. 42,
pL xviii. fig. B.

Habitat.— Ki Islands, Station 192 ; depth, 140 fathoms. One specimen.

64 THE VOYAGE OF H.M.S. CHALLENGER,

Lepidotrigla, Gthr.

Lepidotrigla spiloptera.

Lepidotrigla sinloptera, Giinth., Keport on the Shore Fishes, Zool. Chall. Exp., part vi. p. 42,
pi. xviii fig. C.

Habitat. — Ki Islands, Station 192; depth, 140 fathoms. One specimen.

Family Cataphracti.

Peristethus, Laeep.

The Mailed Gurnards are eminently bottom-fishes, which rise to the surface still more
rarely than the true Gurnards. Some of the species have been lately discovered in
deep water ; probably all will be found to descend to considerable depths.

Peristethus miniatum.

Peristidium miniatum, Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, pp. 349, 480; BuU. Mus.
Comp. Zool., vol. X., 1883, p. 212.

' D. 7-8/18. A. 17-18. L. lat. 27-28.

Very similar to, and with regard to armature agreeing with, the West Indian
Peristethus brevirostre, but described as having four series of spiny plates on each side ;
the spines of the abdominal plates very weak posteriorly. The length of the prseorbital
processes is thrice and a half in the distance between their extremities and the anterior
margin of the orbit. A single pair of spines on the upper surface of the snout. Inter-
orbital space deeply concave. The ridge of the prseoperculum terminates posteriorly in
a depressed, short, sharply-pointed spine. Lower jaw with small tentacles on each side.
The long tentacles at the angle of the mouth are fringed, and reach to the base of the
pectorals. Crimson.

Several specimens were taken by the U.S. steamers between lat. 32° and 40° N.,
long. 70° and 79° W., in the Gulf Stream, at depths varying from 115 to 192 fathoms.

Peristethus moluccense, Blkr.

Found in various parts of the East Indian Ai'chipelago, and discovered by the
Challenger in 140 fathoms, at the Ki Islands, Station 192.

REPORT ON THE DEEP-SEA FISHES. .65

Peristethus murrayi.

Peridethm murrayi, Giintli, Eoport on the Shore Fishes, Zool. Chall. Exp., part \'i. p. 52,
pi. xxxii. fig. A.

Discovered by the Challenger in the Sea of Banda, at a depth of 200 fathoms.

Peristethus liorhynchus.

Peristethus UorhyncJuis, Gunth., Repoit on the Shore Fishes, Zool. Chall. Exp., part vi. p. 56.

First found at Manado, and rediscovered by the Challenger at the Admiralty Islands,
in 152 fathoms.

Peristethus micronema.

Peristedion imberbe, Poey, Eepert. Fis. Nat. Cuba, ii. pp. 158, 462.
Peristedion micronemus, Poey, Ann. Lye. Nat. Hist. New York, ix. p. 321.

This species must inhabit the same depth as Polymixia nohilis, as Poey found it in
the stomach of a specimen of that fish. He considers it as a distinct species charac-
terised by the minute size of the mandibulary tentacles.

Peristethus truncatum.

Peristethus frmicatum, Giiiith., Report on the Shore Fishes, Zool. Chall. Exp., part vi. p. 7.

In the Report on the Challenger Shore Fishes, p. 7, this species was described from
the coast off Pernambuco ; but it was stated to be uncertain whether the fish was caught
in 30 or 350 fathoms.

Agonus, Bl. Schn.
Agonus decagonus.

Agonus decagonus, Bl. Schn., p. 105.

Asjndophorus spinosissimus, Kroyer, Nat. Hist. Tidsskr., i., 1844, p. 250; Gaimard, \'oy.

Scand., pi. V.
„ malarmoides, Deslongch., M6m. Soc. Linn. Norm., vol. ix., 1853, p. 167.

Agonu.s decagonus, Collett, Norges Fisk. p. 40; Norsk. Nordh. Expcd. Fisk., p. 44, pi. ii. figs.

" 11-12.
„ ,, Lilljeb., Sverig. och Norg. Fisk., p. 193.

An Arctic littoral species, extending from the coasts of Greenland and Newfoundland
to Iceland, Spitzbergen and Norway, and descending to a depth of 260 fathoms.

(zool. chall. EXP. — PART LviL — 1886.) Lll 9

6G THE VOYAGE OF H.M.S. CHALLENGER.

Family Discoboli.
Cyclopterus, Artedi.

The common Lump-sucker, Cijdo2^tenis lumjnis, is a shore fish, and has never been
observed to go into deep water, whilst its more northern representative {Cyclopterus
spinosus), like many other Arctic species, descends into the frigid strata of the deep sea.

Cycloptera spinosus.

Cudopteriis spinosus, Miill., Prodr., p. ix.

„ „ Gaimard, Voy. Scand. Poiss., pi. iv. fig. 2.

„ ,, Giintli., Fisb., vol. iii. p. 157; Proc. Zool. Soc. Lond., 1877, p. 293

(fig. of young), and p. 475.

„ „ Jordan and Gilbert, Synopsis, p. 746.

Eumicrotremus spinosus (Gill), CoUett, Norsk. Nordli. Exped. Fisk., p. 67, pi. ii. fig. 13.

This species extends from the southern coast of Greenland to lat. 82° N., and has
been obtained by the North Atlantic Expedition at a depth of 129 fathoms. If CoUett's
supposition, that the number of dorsal rays varies in this species between nine and twelve,
be confirmed by a more extensive series of examples, Cyclopterus orbis, from the North
Pacific, would probably prove to be the same species.

__ Liparis, Art.

Liparis fahricii.

Liparis fahridi, Kriiyer, Nat. Hist. Tidsskr., ii., 1847, p. 274.

„ „ Liitken, Kara-Havets Fisk. in Dijmplma-Togtet, jx 146, tab. xv. figs. 4-5.

The only record of the occurrence of this common Arctic littoral species beyond
the 100 fathoms line is by Liitken, who states that he received a great number of
specimens from the Kara Sea, where they were obtained at depths varying from 46 to
106 fathoms.

Liparis micropus, n. sp. (PI. XIL fig. B).

D. 35-37. A. 35-36.

This species approaches in some respects the genus Carcproctus, having the tail
particularly attenuated, and the ventral disc of unusually small size. The head is large
and thick, about one-fourth of the total length, the caudal included. The interorbital
space equals in length the postorbital portion of the head. Eye entirely in the

EEPOET ON THE DEEP-SEA FISHES. 67

anterior half of the head and one-fifth of its length. Nostrils not tubulated. Cleft of
the mouth not extending to the front margin of the eye. Teeth simple, unicuspid.

Vertical fins continuous, caudal very narrow and pointed. The origin of the anal is
opposite to the eighth dorsal ray. Form of the pectoral typical, the foremost rays being
opposite to the anterior margin of the venti'al disc. Ventral disc circular, small, one-
fourth of the length of the head, situated immediately Ijehind the level of tlie eye. Vent
very close to ventral disc. Colour light greyish or purplish.

Habitat.—" Knight Errant," 1882, Station 9 ; depth, 608 fathoms. Two specimens,
2 and 3^ inches long.

" Knight Errant," 1880, Station 8 ; depth, 540 fathoms. One specimen, 3^ inches long.

A specimen obtained on the cruise of the "Porcupine" in 180 fathoms, north of
Shetland, was referred by me to Liparis liparis, to which it probably belongs ; it is,
however, in too bad a state of preservation to be identified with certainty.

Liparis gelatinosus.

Gydopterus gelatinosiis, Pall. Spioil., vii. p. 19, tab. iii.

Ldparis gelatinosus (Cuv.), EeinL, Oversigt K. D. Vid. Selsk. ForhanJl., 1843, p. Ix.xvii.
„ Giinth., Fish., vol. iii. p. 163 (translat. Pall.).'

{Careprodus) reinhardi, Kroyer, Nat. Hist. TiJsskr., i., 1862, p. 252.

„ „ Collett, Norsk. Nordh. Exped. Fisk., p. 57, pi ii. figs. 15-16.

„ „ Jordan and Gilbert, Synopsi-s, p. 7-10.

„ ,, Ltitken, Kara-Havets Fisk. in Dijmphna-Togtet, p. 152.

D. 54-55. A. 45-46. C. 11-14. P. 32-33. Vert. 64. Cocc. pyL 48.

Tail very long and attenuated. Ventral disk very small, scarcely larger than the
eye, immediately below the front part of which it is placed. Pectorals deeply notched,
extending forwards to the mandibulary symphysis. Vent close to the disk. Skin
glutinous ; body semitransparent. Abdominal cavity black.

An Arctic circumpolar species, fir.st described from the North Pacific (Behring's Strait),
afterwards found on the Greenland coast, and recently discovered by the North Atlantic
Expedition about Jan Mayenand Bear Island, and off Arendal, at depths varying between
263 and 658 fathoms; also found in the Kara Sea.

' This work has been referred to by Collett in a somewhat singular manner. As no specimen of Liparis gelatinosus
was in the British Museum at the time of the publication of the third volume of the Catalogue, a literal translation
ot Pallas and Steller's account was given, and stated to be such. Yet Collett quotes the translation with the addition
of a 1 rather than the original authors ! Jordan also adds a mark of interrogation to his quotation of the Catalogue,
but this must have been an oversight, as his diagnosis is shaped after the one given in that work.

68 THE VOYAGE OF H.M.S. CHALLENGER.

Paraliparis.

Paraliparis, Collett, Norsk. Nordh. Exped. Fisk., p. 53.
Monomitra, Goode, Proc. U.S. Nat. Mus., vol. vi., 1884, p. 109.

General shape of the body and head as in Liparis, the skin being very loose, thin,
and easily torn. The peculiar posterior process of the infraorbital ring, the structure
of the vertical fins, and the dentition are also the same as in Liparis. But the ventral
fins are absent, and the lower rays of the pectoral fin are entirely detached from the
others, or nearly so.

Paraliparis bathyhius (PI. XII. fig. C).

Liparis {Paraliparis) batJiybii, Collett, Norsk. Nordh. Exped. Fisk., p. 52, pi. ii. fig. 15.

D. 60. A. 50. P. 12/3.

The specimen obtained by the "Knight-Errant" is of the same size and sex as the typical
example, and also in a rather indiSerent condition, nearly the whole body being denuded of
skin. Fortunately those parts about which CoUett's description leaves us in doubt, are well
enough preserved to confirm his supposition that this fish is the type of a distinct genus.
The ventral disc, or indeed any external trace of ventral fins, is absent, and the lower
portion of the pectoral fin is separated from the upper by a smooth space without any of
those intermediate filaments which are shown in CoUett's figure. The three lower rays '
are connected by membrane to their tips, and form a fin by themselves. The posterior
part of the vertical fins is also less elevated, the rays being directed more backwards.
The vent occupies a similarly advanced position as in Liparis. Our specimen is distended
with apparently mature ova of the size of hemp-seed, as was the case in the type.

Habitat. — "Knight-Errant," Station 8, 1882; depth, 640 fathoms. One specimen,
7g inches long.

CoUett's specimen was obtained in 658 fathoms, 108 kilometres west of Bear
Island.

Paraliparis liparinus.

Amitra liparina, Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 478.
Monomitra liparina, Goode, loc. cit., vol. vi., 1884, p. 109.

D. 67. A. 54. C. 6. P. 17/6.

Similar in form to Paraliparis bathybius, but with thick, lax, slimy skin. Teeth
weak, paved. The dorsal fin begins over the end of the pectoral; and the anal under the
eighth or tenth doral ray. Yellowish-white, dusky towards the tail and on the head.

1 The number of fin-rays forming the detached portion of the pectoral fin is three only, and not more, as would
appear from the figure, in which the artist has represented the external folds of the skin, which loosely envelops the
three rays.

REPORT ON THE DEEP-SEA FISHES. 69

Two specimens were obtaiued, of wliicli the larger is 7 inches long, by the U.S.
Fish Comniissiou, off the coast of New England, in 487 fathoms.

There are certain discrepancies between the description of this species and of the
European specimens of the genus which made me long hesitate before referring them to the
same genus. Goode says that pseudobranchite are present ; Collett denies this, and in our
specimen of Paraliparis hathyhius they are certainly absent. The teeth are pointed in
Paraliparis hathyhius, and described as paved in Paraliparis lipannus. Finally, Goode
does not remark upon the isolation of the lower pectoral rays which is so conspicuous in
our specimen, although it should be remembered that Collett believes that he noticed
intermediate rays in his example, which, without doubt, is of tlic same species as the
one figured in this work. On the other hand, the agreement in the majority of the other
essential points is great, so that I prefer at present to leave the fishes iu the same genus.
Probably the statement so distinctly made by Collett, viz. , that the ventral fins had been
accidentally lost, as well as the black colour which gives to the European species a very
diff'erent appearance, has prevented Goode from comparing his specimens \vith
Paralip)aris.

Paraliparis memhranaceus, n. sp. (PI. XII. fig. D).

D. ca 70. A. ca 70.

The specimen from which the following description is taken is onlj' 60 mm. long, and
therefore presumal^ly young ; and it is uncertain whether it represents a species iu which
certain embryonic characters are persistent, or merely an early stage of development.

Its head is large, compressed, about as high as long, with the upper profile
descending in a parabolic curve. The abdominal cavity, black and transparent
through the integuments, is excessively short ; the tail compressed and gradually
tajjering into a fine point. The whole of the integuments are colourless ; with minute
scattered points of pigment. A broad median dorsal fold rises from the top of the snout
and is continued to the extremity of the tail, gradually disappearing as it apj^roaches the
caudal fin, which is represented by two or three extremely fine and rather long tenninal
filaments. The fold is highest aljove the posterior portion of the abdomen ; there also
fin-rays commence to be developed, which on the anterior half of the tail are distinct enough,
but become more crowded posteriorly and almost indistinguishable. The anal has a
similar structure ; it also starts as a fold from the vent, which is far advanced, opposite to
the hind margin of the orbit ; rays are developed from the posterior end of the abdominal
cavity, whence the fin is continued in the same manner as the dorsal.

Pectoral fin very large, with a very broad base, extending from the upper end of the
gill-opening forward nearly to the hyoid bone ; its principal portion consists of an

70 THE VOYAGE OF H.M.S. CHALLENGEE.

extremely delicate membrane, in which rays are visible like fine striae, and which on its
hinder margin is provided with long fringes. The eight lower or anterior rays are quite
free but not separated by an interspace from the remaining part of the fin. The bones
of the head are extremely thin, forming cavities on the top and the snout. The eye is of
moderate size, about two-sevenths of the length of the head, a little shorter than the
snout, and considerably less than the width of the interorbital space, which is very convex.
Jaws even in front, the maxillary extending nearly to the hind margin of the orbit.

As described by Goode in ParaUparis lijyarinus, the gill-openings are closed below,
and restricted to small slits below the operculum.

One specimen, 2 J inches long, was obtained off Cape St. Vincent, Station 310, at a
depth of 400 fathoms.

Family G o b 1 1 d /E.

Callionymus, L,
Callionymus kaianus.

Callionymiis kaianus, Giinth., Eeport on the Shore Fishes, Zool. Chall. Exp., part vi. p. 44,
pi. six. fig. B.

Habitat. — Ki Islands, Station 192 ; depth, 140 fathoms. One specimen.

Callionymus calauropomus, Rich.

Gallmiymus calauropomus, Giinth., Eeport on the Shore Fishes, Zool, Chall. Exp., part vi. p. 53.
Habitat. — Philippine Islands, Station 204b; depth, 115 fathoms. One specimen.

Family B L E N N 1 1 D .E.

Anarrhichas, Art.

The common European Wolf-fish, Anarrhichas lupus, is a littoral species which does
not extend so far northwards, or reach so great a depth as the two following North
Atlantic forms, which are considered to be specifically distinct by all Scandinavian and
North American authors.

Anarrhichas minor, Olafsen.

Anarrhichas iMntherinus, Zouiew.
Anarrhichas egerti, Steenstrup.

Anarrhichas minor, Collett, Forhandl. Vidensk. Selsk. Christ., 1880, p. 45.
,, „ Lilljeb., Sverig. och Norg. Fisk., p. 540.

An Arctic species which in southern latitudes descends into deep water, having been
found on the north-west coast of Norway in 200 fathoms. The British Museum has

REPOKT ON THE DEEP-SEA FISHES. 71

received from the Smithsonian Institution a specimen, which was captured at the same
depth in \at. 43° 52' N., long. 59° W.

Anarrhichas latifrons, Steenstrup.

Anarrhlchas latifrons, CoUett, Forhandl. Yidensk. Selsk. Christ., 1880, j). 46, pi. 2.
» „ Lilljeb., Sverig. och Norg. Fisk., p. .540.

Likewise an Arctic species, which has been caught off Finmarkeu in 100 fathoms;
but the British Museum has received from the Smithsonian Institution a specimen, which
was caught in 280 fathoms, in lat. 42° 27' N., long. 64° 20' W.

Blenniops, Nilss.
Blenniops ascanii.

Blennius ascanii, Walbaum, Art. renov., iii. p. 173.

Blenniops ascanii, Giinth., Fisli., vol. iii. p. 284; and Ann. Mag. }sat. Hist., 1874, vol. xiii. p. 139.

Carelophus ascanii, Strom, Norsk. Vid. Selsk. Skr. 1881, p. 7.5.

„ „ CoUett, Nyt Mag. f. Naturvid. Christ., xviii. 1884, p. G8.

This Blenny was obtained during the cruise of the "Porcupine" between Shetland and
Faroe in 180 fathoms, and is recorded by Strom from 140 ftithoms in Throndhjem Fjord.

Family Trachypterid..e.

Although Ribbon-fishes are spread over the whole area of the tropical and temperate
zones,^ and must be very abundant in the abyssal fauna, nothing is known of their habits
and their vertical distribution. Of the expeditions in which the deep-sea dredge or trawl
has been used, the Challenger Expedition is the only one which obtained a single example,
and that of very small size. Large and long individuals, of course, would easily escape,
but one might have expected the capture of a certain number of young examples. It is
not improbable that such small specimens were actually caught, but destroyed during
the ascent of the dredge, as the fragile condition of their body can hardly be expected
to resist the force and pressure of the current passing through the net. Adult
specimens probably pass a great portion of their life on the bottom, but the not
uncommon occurrence of young Trachypteri near the surface seems to indicate that
they live at any depth where the water ceases to be affected by the surface agitation.

' It is noteworthy tliat no instances have been recorded of their occurrence on the western coasts of the Atlantic.

72 THE VOYAGE OF H.M.S. CHALLENGEK.

Trachypterus, Gouan.

A considerable number of species have been described, some of which are without
doubt merely stages of growth, w^hile others were described by authors who had no
opportunity of comparing them with wxU-authenticated specimens. On the other hand,
in a genus which seems to comprise a jalurality of species, but in which the distinctive
specific characters are obscured by a variety of circumstances, it is difficult to arrive at
a satisfactory conclusion with regard to the validity of the species described. One of
the most common and best known is the Vagmaer or Deal-fish, Trachyptei'iis arcticus,
from the North Atlantic, of which almost every year one or more specimens are secured
on the Norwegian and British coasts after severe gales. From the Mediterranean and
neighbouring parts of the Atlantic several species have been described, viz., Trachy-
pterus tasnia (Bl.), of which, according to Emery, Trachypterus Jilicauda (Costa),
Trachypterus iris (Walb.), and Trachypterus spinolse (C. and V.), are successive stages
of growth ; Trachypterus gryphurus (Lowe) ; Trachyp>terus liopterus (C. and V.),
Trachypterus rilppcllii^ (Gthr.) ; Trachypterus cristatus (Bonelli) ; and Trachypterus
repandus (Metaxa, Costa). From Cuba a species is described as Trachypterus trachy-
urus by Poey, and one from the East Indian Archipelago as Trachypterus semiophorus
by Bleeker. The instances of the occurrence of this genus in the Pacific are very
few, viz., Trachypterus altivelis (Kner.), from Valparaiso, Trctchypterus weychardti
(Philippi), also from the Chilian coasts, and Trachypterus araimta^ (Clarke), from the
coast of New Zealand.

The example in the Challenger collection is only 1^ inches long, and was obtained
at Station 207, near the Philippine Islands, when the dredge was used at a depth
of 700 fathoms ; but as this extremely delicate specimen was preserved in a
tolerably good condition, it is probable that it entered the dredge at no great distance
from the surface. It is extremely similar to the small Trachypterus figured by Costa
(Faun. napoL, Tab. ix.), under the name of Trachypterus re2mndus. It has the same
shape of body, the same elongate caudal fin, and the anterior dorsal rays and
ventral fins are prolonged in an extraordinary manner. Also the tail and body are
ornamented with transverse dark spots similarly arranged. But the prolonged fin-rays
are shorter than in Trachypterus repandus, and lack lobes of skin.

It seems to me that both these small individuals represent the young stage of species
of Trachypterus, which, when older, lose the extraordinary development of their fin-
rays. Probably the fish from the Philippine Islands is a species distinct from that

' The specific distinctness of this fish has also been doubted ; and, therefore, I beg again to draw attention to the
position of tlie first lateral black spot, in which the specimen diff'ers from the other Mediterranean specimens of the
same size which are known to me.

REPORT ON THE DEEP-SEA FISHES. 73

figured by Costa, but it is impossible to say whether it is the young of a species
already known or of one peculiar to that part of the Indian Ocean.'

Stylophorus, Shaw.

This extraordinary type is still known from the single example only {Stylophorus
chordatus) which was found at the beginning of this century between Cuba and
Martinique. Since I examined this fish in 1860, it has so much deteriorated, that no
further information can be gleaned from it beyond that which I gave in the Catalogue
of Fishes, vol. iii. p. 306. It has recently been transferred from the Royal College
of Surgeons to the collection of the British Museum.

Regalecus, Brlinn.

Oar-fishes have the same wide range in the depths of the sea as Deal-fishes, and
like these, they have singularly not yet been observed on the American coasts of the
Atlantic. They fall still more rarely into the hands of competent observers than the
Tracliiipteri, and then generally in a more or less mutilated condition. The usual
method subsequently adopted of preserving them dry or stuffed completes their destruc-
tion and renders them aU but useless for future examination and comparison.' Hence,
any attempt at distinguishing separate species is at present open to serious objections.
With regard to the specimens found in the North Atlantic, Liitken,' and CoUett,'' have
come to the conclusion that they are all the same species.

In the following list I have endeavoured to enumerate the specimens, the capture of
which has been hitherto recorded ; and it is noteworthy that by far the greater propor-
tion of their captures fall into the stormy season, at any rate in the northern hemi-
sphere. Thus, of those obtained on the British and Scandinavian coasts, we find four in
the month of January, five in February, eight in March, two in April, one in May,
June, and July each, two in August, one in September, and one in October. Of the
six captured off" the Cape of Good Hope and in New Zealand, one is recorded for each
of the months of February, May, June, July, September, and October.

1 Since tlie above paragraph was written (1878), C. Emery lias demonstrated by a series of young examples of
Trachypterus txnia, that the fin-rays commence to grow when the young is about 6 mm. long, and continue to
lengthen till the fish is about four times that size, after which period a shortening of the rays takes place. Alt. Accad.
Line, vol. iii., 1879, p. 390, c. figs. 1-6.

2 I would recommend to all who may happen to secure one of these valuable specimens, to cut the fish into
convenient lengths and preserve them in the strongest spirit, each piece WTapped separately in muslin.

3 Vid. Meddel. nat. Form. KjiPhenhMvn, 1881, p. 190 ; Oversigt K. D. Vid. Setsk. Forhandl., 1882, p. 206.
" Forhandl. Vidensk. Selsk. Christ, 1883, No. 16.

(ZOOL. CHALL. EXP. — PART LVII. — 1886.) -L" 1"

74

THE VOYAGE OF H.M.S. CHALLENGER.

1.
2.

3.

4.

5.

6.

7.

8.

9.
10.
11.
12.
13.
14.

Ophidium glesne. Ascan,

Regalecus glesne. Ascan,

') ))

Gymoietrus grillii. Lindr.,

Regalecus glesne. CoUett,

Regalecus hanhsii

Liitken,'

I. Scandinavia.'

. Glesvser, near Bergen,

. 1740

Febr.

jj

. 1766

Vseroe, near Glesvser,

. 1769

June

Bergen,

. 1791

March

Hitteren near Throndhjem

, 1797

Aug.

Svaerholt (Finmarken),

1852

Febr.

Nordfjord (Bergen Stift),

1855

Alstahoug (Norland),

1859

Molde,

1860

Jsederen, .

1867

March

Stavanger,

1881

April

Langesund,

1882

May

Tromso, .

1883

Febr.

Faroe,

1852

II. British Coasts.

1.
2.
3.
4.
5.
6.

9. Gymnetrus hanksii. Hancock
10. Regalecus glesne. Gray,
11.

12. Gymnetrus hanksii. Hogg, Ann. and

Mag. Nat. Hist., 1866, vol. xvil
p. 390; Tristram, Proc. Zool. Soc
Lond., 1866, p. 147,

13. Gymnetrus hanksii. Hogg, Ann. and n

Mag. Nat. Hist., 1866, vol. xviii. [ Whitby,
p. 136. .

Whitby, . ■ .

. 1759

Jan.

Newlyn, .

1788

Febr.

Newcastle,

1794

March

Filey,

1796

March

Fern Islands,

1800

)>

1800

Crovie, near Macduff,

1844

March

Alnmouth,

1845

Jan.

CuUercoats,

1849

March

Eedcar,

1850

Jan.

Cromarty,

1851

Sept.

Durham, .

1866

March

s

1 See Collett, Om de i vort Aarhundrede ved de norske Kyster strandede Exemplarer
Forhandl. Vidensk. Selsk. Christ., 1883, No. 16.

2 Vid. Meddel. nat. Foren. Kjiphenham, 1881, p. 205.

. 1866 April

af Slaegten Regalecus ;

EEPOET ON THE DEEP-SEA FISHES. 75

14.
15.
16.
17.
18.
19. "Scotsman," Febr. 11,

Yorkshire, . . 1870 Oct.

Amble, opp. Coquet Island, 1876 March

Dunnet Bay, Caithness, . 1877 July

St. Ancbews, . . 1880 Aug.

Staithes, Yorkshire, . 1880 Jan.

Kinuaird Head Lighthouse, 1884 Febr.

III. Mediterranean.

About half a dozen specimens are known to have been observed on the coasts of the
Mediterranean ; those described by Risso and Valenciennes were captured near Nice,
some in the month of May, but no record as regards the details of their capture seems to
have been preserved.

1. Gymnetrus gladius. Jourdain, Comptes ") ^

1 lo^ro 1 ^. ^n > Palavas, Herault, . . 1871 April

rendus, 1872, vol. 74, p. 58, . ) ^

IV. Bermudas.

1. J. M. Jones, Proc. Zool. Soc. Lond.
1860, p. 185, .

[Hungry Bay, . .1860 Jan.

V. Cape of Good Hope.

1. Gymnetrus capensis, C. V., vol. x. p. 376, . about 1834

2. From a drawing in my possession, . Simon's Bay, . 1865 Sept. 23

3. Layard, Proc. Zool. Soc. Loud., 1868, ) ^ 1 1 t> -.r,^^ tk i

•' } Table Bay, . 1868 tebr.

p. 319, . . . .) ^

VI. Indian Ocean.

1. Gymnetrus russellii. Russell, vol. i. } ... ^ __„„ ,, ,

•^ I Vizagapatam, . . 1788 March

p. 40, . . . . J ° ^ '

VII. New Zealand.

1. W. T. L. Travers, in Giinth., Rsh., | ^^^^^^ , _ _ ^g^^ q^^

vol. iii. p. 307, . . .J

2. ige^raZecws i9acz>«s, Haast, New Zeal. I ^^^^ g^..^^^^^^ _ _ ^g^g ^^^^^
Trans., vol. x. p. 246, . . )

1 Fragments of this specimen are in the British Museum.

76 THE VOYAGE OF H.M.S. CHALLENGER.

3. Haast, loc. cit., p. 250, . . Karamea District, . . 1877 July

4. Parker, loc. cit, . . . Moeraki, . . about 1881

5. Regalecus argenteus, Parker, New Zeal. ^

Trans., vol. xvi. p. 284; and f Moeraki,^ . . . 1883 June

Trans. Zool. Soc, vol. xii. p. 5, .J

Family Lophotid^.

Of these singular fishes only a few specimens have fallen into the hands of naturalists,
and have been referred to two species, Loplwtes cepedianus and Lophotes cristatus.-
They were obtained in the Mediterranean, off Madeira, and in the Sea of Japan. Most
probably they are deep-sea fishes like the Trachypteridee which they resemble in the
general shape of the body, but their skeleton as well as their soft parts is of a firmer and
more coherent texture.

ACANTHOPTERYGII PHAEYNGOGNATHI.

Heliastes.

Heliastes roseus.

Heliastes roseus, Giinth., Eeport on the Shore Fishes, Zool. ChaU. Exp., part vi. p. 45, pi. xx.
fig. D.

Habitat. — Ki Islands, Station 192 ; depth, 140 fathoms. One specimen.

ANACANTHINI.

Family L Y c o D i D yE.

Lycodes, Reinh.

This genus is represented in the Southern as well as Northern Hemisphere, but it
would appear from the present state of our knowledge that the Antarctic species do not
descend to so great a depth as the Arctic. Probably all of the latter will be found to
reach beyond the vertical limit of 100 fathoms, but up to the present time this has been
ascertained of those species only which are enumerated here. Collett in his valuable
contribution to the deep-sea fauna (Norsk. Nordh. Exped. Fisk.) has given a very complete
bibliography of this genus.

1 The skeleton of this specimen is now in the British Museum.

2 Johns., Proc. Zool. Soc. Land., 1863.

REPORT ON THE DEEP-SEA FISHES. 77

Lycodes esmarkii.

Lycodes esmarkii, Collett, Norsk. Nordh. Exped. Fisk., p. 84, pi. ii. figs. 19-21, pi. iii. fig. 22;
Nyt Mag. f. Naturvid. Christ., vol. sviii., 1884, p. 73.

This species, which has been distinguished from Lycodes vahlii hy Collett on perhaps
too indistinct characters, was found by the North Atlantic expedition off the Lofoten
Islands and on the north west-coast of Spitzbergen in depths varying from 260 to 459
fathoms. During the cruise of the " Knight Errant " in the Faroe Channel, two specimens
10^ inches long were obtained in 608 fathoms (Station 9, August 23, 1882). Indi-
viduals from the Varangerfjord, for which we are indebted to Hr. CoUett, exceed 2
feet in length. According to him the species occurs also in the AVestern Atlantic, off the
coast of Nova Scotia.

Lycodes reticulatus (PI. XIII.).

Lycodes reticulatm, Reinh., K. dansk. Vidensk. Selsk. Afhandl, vii., 1838, p. 167, tab. vi.
„ „ Liitken, Vid. Meddel. nat. Foreu. Kjobenliavn, 1880, p. 318.

„ „ Collett, Norsk. Nordh. Exped. Fisk., p. 105.

Lycodes perspicilluni, Krijy., K. dansk. Vidensk. Selsk. Afhandl, xi., 1845, p. cexxxviii.,
Gaim., Voy. Scand. Poiss., pi. vii. ; Nat. Hist. Tidsskr., 1862, p. 289
(young).
Lycodes rossii, Malmgren, Ofversigt k. Vetensk.-Akad. FLirliandl., 1865, p. 516 (young)

(Spitzbergen).
Lycodes gracilis, Sars, Forhandl. Vidensk. Selsk. Christ., 1866, p. 40, pi. i. figs. 1-3 (young)

(Christiania Fjord).
Lycodes lUtkenii, CoUett, loc. cit, p. 103, pi. iii. fig. 25.

„ „ Liitken, Kara-Havets Fisk. in Dij mphna-Togtet, tab. xvi.

The first specimens of this species were brought from the coast of Greenland ; at a
later period young specimens of apparently the same species were found at Spitzbergen
and on the coast of Norway, and described under distinct names. Finally Hr. CoUett is
of opinion that an example, 14 inches long, obtained in the open sea, west of North
Spitzbergen, in 459 fathoms, also represents a distinct species, though very closely allied
to Lycodes i^eticulatus, which he named Lycodes lilthenii. On reading his somewhat
lengthy description of this individual, I could not help entertaining some doubts as
to the propriety of separating it from Lycodes reticulatus, and these doubts were
increased by the examination of an example, 22 inches long, which the " Knight Errant "
obtained in the Faroe Channel at Station No. 9, August 1882, in 608 fathoms. It might
be referred to either Lycodes reticidatm or Lycodes lUtkenii, or distinguished as a
separate species, if no regard be paid to changes of form (to which very old examples
must be subject), or no allowance be made for slight variation. In a paper on the fishes
of the Kara Sea, received whilst this Report is passing through the press, I find that

78

THE VOYAGE OF H.M.S. CHALLENGER.

Liltken retains the name projDosed by Collett, for specimens which were obtained in that
part of the Arctic Ocean.

The specimen is thickly covered with a stratum of coagulated mucus, which can be
peeled off in large coherent flakes, filling the pits of the skin of the body and firmly
adhering to the broad folds which are developed along the course of each anal ray. It
seems to me evident from the appearance of this mucous layer that it is not merely a
port-mortem result, but that the body was covered with it during life. The colour of
the entire fish is a uniform dirty white.

The length of the head is equal to, or perhaps a little more than, its distance from
the origin of the anal fin ; the snout is produced and the mouth wide ; the eye lies in
the anterior half of the length of the head, and is distant from its fellow by only about one
horizontal diameter ; however, the general integument of the head passes so gradually into
the transparent cornea, that it is difficult to define the exact dimensions of the eye.
Nostril near the extremity of the snout, in a short tube. The maxillary extends just to
the vertical from the hind margin of the orbit.

The skin of the head is naked, but with irregular pits on the lower parts of the
cheeks, in which, however, no scales can be detected. The skin of the neck is likewise
pitted, whilst a broad smooth stripe of skin runs aldng each side of the neck and for
some distance along the back of the trunk. Sides of the body and tail pitted, each pit
containing a rudimentary hyaline scale. The lower parts of the abdomen deeply pitted,
without scales, the pits being filled with a deep layer of mucus which also covers the
lower part of the head and the pectoral and anal fins. A single median lateral line ; no
trace of an abdominal line.

The dorsal fin commences above the commencement of the second third of the
pectoral fin ; it is enveloped in thick skin, which forms permanent folds running in the
direction of the rays ; anal similarly formed, but with the folds much higher ; it is
composed of seventy-two rays. Pectoral fin very broad, three-fifths as long as the head ;
ventrals very short and small. The specimen is a male and has several semidigested
young specimens of its own species, or of a species closely allied to it, in its stomach.

Measurements : —

Total length,

Total length without caudal rays,

Height below origin of dorsal,

Ijength of the head.

Distance of vent from end of snout,

Length of snout, .

Length of eye,

Length of pectoral fin.

Length of ventral fin,

Distance of ventral fin from vent,

Inches.

Line

22

21

2

4

. .«

5

7

10

1

9

6

3

5

4

6

6

REPORT ON THE DEEP-SEA FISHES. 79

Ly codes frigidiis.

Ly codes frigidus, Collett, jSTorsk. Nordh. Exped. Fisk., p. 90, ])1. iii. figs. 23-24.

The specimens described by Collett under this name were obtained by the North
Atlantic expedition in the tract of ocean surrounding Bear Island, Spitzbergen, and also
on the banks of Heligoland and Lofoten. The depth varied from 260 to 1333 fathoms.
The " Knight Errant " met with the same species in the Faroe Channel, capturing a great
number of young and half-grown specimens on the 17th August 1880, at Station 8, in
540 fathoms, and in August 1882, at Stations 8 and 9, in 608 and 640 fathoms. Some
of these specimens agree perfectly with the characters assigned to the species by Hr.
CoUett (who had the kindness to send to me one of his own specimens for comparison),
but other specimens of the same size from the same haul, and possibly of the same brood,
show variations in the development of the lateral line and in the extent of scaling, so
that it would have been difficult, or rather impossible, to identify them from the descrip-
tions only. And it seems to me very doubtful whether the lateral line and the scaling
should be employed, in the fishes under consideration, so positively for specific distinction
as has been attempted by Liitken and Collett.

Lycodes pallidus.

Lycodes pallidus, Collett, loc. cit., p. 110, pi. iii. figs. 26, 27.

,, „ Ltitken, Kara-Havet's Fisk. in Dijmphna-Togtet, p. 134, tab. xvii. figs. 1-3.

First known from two examples, 3-j and 6j inches long, obtained off north-western
Spitzbergen, in 260 and 459 fathoms, and lately recognised by Ltitken in specimens from
the Kara Sea, which were caught at a depth of between 46 and 106 fathoms.

Lycodes seminudus.

Lycodes seminudus, Reinh., Vid. Selsk. Naturv. Afhandl., vii., 1838, p. 221.
„ „ Liitken, Vid. Meddel. nat. Foren. Kjubenhavn., 1880, p. 325.

„ „ Collett, Norsk. Nordh. Exped. Fisk., p. 113, pi. iv. fig. 28.

Known from two examples, one from Greenland, and the other from Spitzbergen
(260 fathoms).

Lycodes murcena (PL XIL fig. A).

Lycodes murorna, Collett, Norsk. Nordh. Exped. Fisk., p. 116, pi. iv. figs. 29-31.

Of this interesting species many specimens were collected during the cruise of the
"Knight Errant," viz., at Station 8 (August 17, 1880) in 540 fathoms, and at Station 9
(August 23, 1882) in 608 fathoms. The typical specimens came from banks lying off

80

THE VOYAGE OF H.M.S. CHALLENGER.

Heligoland, and from the open sea, off Bear Island and Spitzbergen, from depths varying
between 350 and 658 fathoms.

I have nothing to add to the long description given by CoUett, except that our
specimens, which vary in length from 2^ to 9 inches, do not confirm his observation that
the scales are most developed in examples of about 6 inches. The scales are equally
rudimentary and irregularly developed on the different portions of the body. Generally
they are present on the tail, but become only conspicuous when the specimen is allowed
to dry. The number of anal rays varies from 87 to 100.

Lycodes sarsii.

Lycodes sarsii, CoUett, OversigtK. D. Vid. Selsk. Forliandl., 1872, p. 62, c. tab.; Norsk. Nordh.

Exped. Fisk., p. 117; Nyt Mag. f. Naturvid. Christ., 1884, p. 78, pi. i.

figs. 3-4.
Anguilla kieneri, Giinth., Ann. and Mag. Nat. Hist., 1874, vol. xiii. p. 138.
Lycodes kieneri, Day, Proc. Zool. Soc. Lond., 1882, p. 536.

The knowledge of this species rests upon two young specimens, of which one,
43 mm. long, was caught in the Hardanger Fjord, at a depth of 100 to 150 fathoms, the

other, 85 mm. long, in the North Atlantic, in
180 fathoms, during the cruise of H.M.S. "Por-
cupine."

This is a shorter species than Lycodes murcena,

the vent being situated at the end of the anterior

third of the total length, and the head occupying

nearly one-half of the distance between the snout

and vent. The pits, with their foramina, in the

circumference of the upper and lower jaw are

deep, but the skin covering the jaws is much less

spongy than in Lycodes murcena; in fact, that

of the upper jaw does not even form a labial

fold. The snout is broad, obtuse, rounded,

scarcely longer than the large eye. Ventrals very slender, two-rayed. Body with

non-imbricate, minute, rudimentary scales, without any markings. Branchiostegals, five.

The specimen is too much shrunk to allow of the fin-rays being counted.

Fig. 3. —Lycodes sarsii, natural size.

Lycodes verrilli.

Lycodes verrilli, Goode and Bean, Amer. Journ. Sci. and Arts, vol. xiv., 1878, p. 474; Bull.
Mus. Comp. Zool., vol. x., 1883, p. 207.
„ „ Collett, Norsk. Nordh. Exped. Fisk., p. 118 {c. fig).

„ „ Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, pp. 337, 477.

Coast of Massachusetts and northward, in from 90 to 603 fathoms.

REPORT ON THE DEEP-SEA FISHES. 81

Lycodes paxillus.

Lyeodes paxillus, Goode and Bean, Proc. U.S. Nat. JIus., 1880, vol. ii. p. U; 1881, p. 477.

Known at first from a single specimen, 14§ inches long, which was caught on the
Le Have Banks in about 300 fathoms, and subsequently from others obtained off the New
England coast in 365 and 487 fathoms.

Lycodes paxilloides.

Lycodes paxilloides, Goode and Bean, Bull. ;Mus. Comp. Zool., 1883, vol. x. p. 207.

Obtained by the U.S. steamer " Blake " off the coast of Massachusetts in from 304 to
466 fathoms.

Lycodon us.
Lyrodonus, Goode and Bean, Bull Mus. Comp. Zoiil., vol. x., 1883, p. '208.

Form of a slender Lycodes. Body with rudimentary scales ; each ray of the dorsal
and anal supported laterally by a pair of sculptured scutes. Caudal distinct, not fully
connate with the other vertical fins. Ventrals present. Gill-opening narrow ; branchios-
tegal membranes broadly joined to the isthmus. Teeth as in Lycodes. Pseudobranchi^
apparently present. Gill-rakers present, in moderate number. Air-bladder and pyloric
coeca apparently absent.

lyycodonus mirahilis.

Lrjcodonvs mirdbilis, Goode and Bean, Bull. Mu.s. Comp. Zoiil., vol. x., 1883, p. 208.

The eye is two-fifths of the length of the head ; the maxillary reaches to the front of
the pupil. The dorsal fin commences somewhat behind the base of the pectorals.

A single mutilated sj^ecimen, measuring 4j inches in its imperfect condition, was
obtained by the U.S. steamer "Blake," in lat. 38° 20' N., long. 73° 23' W., at a depth of
470 fathoms.

Gymnelis, Reinh.

Two species' only are known: one from the Arctic Ocean, the other (Gymnelis picta)
from the Straits of Magellan.

■ I think Hr. CoUett is in error when he identifies Gymnelis picta (GUnth., Fish., vol. iv. p. 324 and Proc. Zool. Soc.
Land., 1881, pi. ii. fig. b) with Gymndis viridis; it is very likely an Antarctic .species, well distinguished by the
number of its fin-rays. The change of colour, wliich takes place during growth, seems to be common to (liimnelU,
Maynea, and some species of Lycodes, and cannot be held as evidence of specific identity.

CZOOL. CHALL. EXP. — PART LVII. — 1886.) Lll 11

82 THE VOYAGE OF H.M.S. CHALLENGER.

Oymnelis viricUs.

Ophidinm viride, Fabr., Faun. Groul., p. 141.

G-ymnelis viridis, Eeinh., K. dansk. Videusk. Selsk. Afhandl., vii., 1838, p. 131.
„ ,, Gaim., Voy. Scand. Poiss., pi. xv.

„ „ Gtinth., Fish., vol. iv. p. 323.

„ CoUett, Norsk. Nordh. Exped. Fisk., p. 123, pi. iv. fig. 32.
„ Kroyer, Nat. Hist. Tidsskr., 1862, i. p. 258.
„ ,, Liitken, Kara-Havets Fisk. in Dijmplina-Togtet, p. 12.5.

An Arctic circumpokr species, locally abundant near the shore, and found by the
North Atlantic Expedition at Jan Mayen in 263 fathoms.

Melanostigma, Gthr.
One species only is known.

Melanostigma gelatinosum.

Melanostigma gelatinosiim, Giinth., Proc. Zool. Soo. Lond., 1881, p. 21, pi. ii. fig. a.
,, „ Goode and Bean, Bull. Mus. Comp. Zocil., 1883, p. 209.

The typical specimen, 5^ inches long, was discovered by Dr. Coppinger in the Strait
of Magellan, in 24 fathoms. Recently this fish has been found off the coast of
Massachusetts in 395 fathoms, thus verifying the conclusion arrived at by the original
describer from its organisation, viz., that it lives at a greater depth than that at which
the typical specimen happened to be caught. But it is not probable that a fish so
eminently specialised for bathybial life as Melanostigma becomes " a shore inhabitant
in seas near the pole," as Messrs. Goode and Bean would have it.

Family G A d i d .■£.

Gadus, Art.
Gadus moi'rkua, L.

Gadus callarias (L.), Lilljeb., Sverig. oob Norg. Fisk., p. 31.
The Cod-fish retires during the summer months into deeper water, and Lilljeborg
and other authors report that it is occasionally caught at a depth of 100 and more
fathoms.

Gadus poutassoii, Risso.

Gadus 23outassou, CoUett, Norg. Fisk., p. 110.

,, „ Lilljeb., Sverig. och Norg. Fisk., p. 112.

This European species habitually lives in deeper water than the majoi'ity of its
congeners, and is not rare at a depth of 100 fathoms on the coast of Scandinavia.

REPORT ON THE DEEP-SEA FISHES. 83

Gadus argenteus.

Gadiculus argenteus, Guichen., Explor. Alger. Poiss., p. 102, pi. vi. fig. 2.
Oadm argenteus, Giinth., Ann. and Mag. Nat. Hi.st., 1874, xiii. p. 1.38.

Since this species was described from the Mediterrcanean, it seems to have been
found only once again, viz., during the cruise of the "Porcupine," in lat. 54° 10' N. and
long. 10° 59' W., in 183 fathoms. The single specimen obtained was 5i indies long.

Mora, Risso.
Mora mediterranea, Risso.

Lowe ^ found this fish at a depth of .300 or 400 fathoms, off Magdalena at Madeira.
The specimens collected by the Challenger were unfortunately destroyed on board ship.

Halargyreus, Gthr.
Halargyreus johnsonii.

Halargyreus johnsonii, Giinth., Fisli., vol. iv. p. 3-t2.

The structure of the typical specimen, and the circumstances connected with its
discovery at Madeira, are sufficient evidence that this fish belongs to the deep-sea fauna.
Numerous examples of the same species, as it seems, apjieared some years ago on the
coast of New Zealand. A few specimens reached the British Museum, but unfortunately
all are in a very bad state of preservation, so that we are unable to give a figure of this
handsome fish. The caudal fin is separated from the other vertical fins by a free
peduncle, and the numbers of the fin-rays, counted in three specimens, are — D. 7 | 57.
A. 41 ; D. 7 I 55. A. 46 ; and D. 7 | 47. A. 41.

Melanonus.

Melanoniis, Giiuth., Ann. anil Mag. Nat. Hist., 1878, ii. p. 19.

Head and body rather compressed, covered with cycloid scales of moderate size, and
terminating in a long tapering tail. Eye of moderate size ; mouth wide, anterior and
lateral ; both jaws with narrow bands of villiform teeth ; vomer and palatines with very-
narrow stripes of minute teeth. Barbel none. Dorsal fin with a short anterior and
posterior division ; the middle portion commences immediately behind the anterior, and
has the anterior rays well developed ; the posterior division is confluent with the extreme
caudal rays and the posterior anal division. Anal like the dorsal, minus its anterior
division. The outer gill-rakers of the first branchial arch strong and long, longer than

1 Pror. Zool. Soc. Land., 1843, y. 91.

84 THE VOYAGE OF H.M.S. CHALLENGER.

the gill-laminse. Ventrals composed of several rays, slightly in advance of the pectorals,
which are narrow. Bones flexible ; mucous cavities of the head of moderate capacity.
Pseudobranchise none.

Allied to Strinsia, but apparently with the dentition and fins modified.

Melanonus gracilis (PI. XIV. fig. B).

MeLanonus grwilis, Giinth., Ann. and Mag. Nat. Hist., 1878, ii. p. 19.

B. 5. D. G I 67. A. 54. 3 D. + C. + 2 A. = 50. P. 10. V. 5.

The head bears, as regards form and general configuration, a striking resemblance to
that oi Melamphaes ; it is of moderate length, equal to the distance of the root of the
ventrals from the vent, rather broad, and with the snout obtuse and arched down-
wards. Only the operculum and praeopercular limb are scaly ; the remainder is
covered with a soft skin, which is roughened by short, soft, keel-like prominences.
The portion covering the front of the snout between the nostrils is of a lighter
colour, with a network of low folds, and similar to the same organ in Melamphaes
typhlops. The muciferous channels are of moderate extent, and open by small but very
distinct pores in the usual manner. One pore, rather wider than the rest, opens in the
centre of the upper surface of the head. The eye is of moderate size, two-ninths of the
length of the head, and rather shorter than the snout. Interorbital space much wider
than the eye, convex.

The mouth is wide, slightly oblique, and not reaching backwards to the hind margin
of the orbit, the maxillary being but little dilated at its posterior extremity. The jaws
are equal in front, or the mandible projects scarcely beyond the upper.

Gill-membranes united below the isthmus for some distance, supported by short
branchiostegals.

The trunk is compressed, passing into the tail, which tapers into an exceedingly
narrow extremity. Of the scales only a small portion has been preserv^ed ; they are
thin, deciduous, marked with numerous concentric striae, and of moderate size. There
seem to be two and a half in a transverse series between the first dorsal and the
lateral line. But the course of the latter cannot be traced, owing to the condition of
the specimen.

The fin-rays are of very delicate structure, connected by a thin membrane, and the
posterior are so closely packed and so fragile that to count them is a matter of some
difficulty. All are more or less directed backwards, especially the posterior.

The first dorsal begins above the root of the pectoral, and is much lower than the
body ; its longest rays are longer than those of the second fin, which maintain nearly the
same length to the end of the fin. The second fin commences immediately behind the

REPORT ON THE DEEP-SEA FISHES. 85

first. A short break separates the second dorsal from the terminal fin which fringes a
portion of the tail, and is equal to about half the length of the head ; its upper and lower
rays are short, much shorter than the few caudal rays proper. The anal fin commences
immediately behind the vent, and is lower than the dorsal opposite. The break in its
continuity is opposite to that of the dorsal.

Both the pectoral and ventral fins have a narrow base, and are slender ; the length of
the former equals that of the head, without snout, and is somew'hat more than that of
the ventrals, which have the second ray prolonged, but do not reach the vent.

The specimen is entirely black, with the exception of the patch of skin in front ©f the
snout, which is of a brownish-grey colour. Fins transparent. Inside of the mouth black,
but not the branchial cavity.

Only one example was obtained in the Antarctic Uceau at Station 1 5 G, in 1975 fathoms ;
it is 6 inches long.

The figures on PI. XIV. represent this specimen of the natural size, also a .side view
of the head, and front view of the snout ; finally, an enlarged view of a scale.

As mentioned above, Strinsia tinea, from the Mediterranean, must be closely allied
to Melanonus, and probably should be included in the deep-sea series.

Merlucc'ms, Cuv.
Merluccius vulgaris (Flem.).

The Hake has been recorded from depths of 115 to 487 fathoms on the edge of the
Gulf Stream ofi" the southern New England coast.' The specimens caught were numerous,
both old and young. Mr. Goode adds : " The adults appeared to be in the middle of the
spawning season (September, 1880), the eggs being separated in the ovaries, and flowing
easily in specimens taken at the depth of 250 and 487 fathoms. This phenomenon is of
the greatest interest and importance, since it may serve to illustrate how other species
common near the shores, such as the Menhaden and Bluefisli {Pomatomus saltatrix)
retreat to deep water to spawn."

Hypsicometes.

Hypsicomete.<, Goode, Pioc. U.S. Nat. Mus., vol. iii., 1881, p. 347.

In introducing this fish into the literature, the author states that "a small specimen,
much contracted and distorted from immersion in strong alcohol, is the only material upon
which to base his description. Although not quite satisfied that the relations of this fish

1 Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, j.].. 337, 476; Bull. Mw. C'omp. Zool, vol. x., 1883, ].. 207.

86 THE VOYAGE OF H.M.S. CHALLENGER.

are most nearly with Merluciidse, he ventures to assign it temporarily to a position in this
family," and proceeds to characterise it thus : —

In general form closely resembling Merlucius, but with the elongate body covered
with (comparatively) large scales. Mouth rather small. A separate caudal. Two dorsal
fins, the first composed of a few long rays, the second with longer base. One elongate
anal. Ventrals well developed, with broad base, composed of six rays. Teeth on the
vomer and in the jaws in two or three rows, rather feeble. Eyes large, near together,
looking upwards. No barbel.

Hypsicometes gobioides.

Hijpsicometes gobioides, Goodc, lor. cit., p. 3-lS.

D. 6 I 17. A. 16. V. 6. L. lat. 58.

The general appearance suggestive of a Gobius. Ventrals far apart, and far in
advance of the pectorals. A large black blotch on the base of the upper caudal rays.

A single specimen, 2 inches long, was obtained by the U.S. Fish Commission, off" the
coast of Rhode Island, in 1 1 5 fathoms.

Lotella, Kaup.^
Lotella marginata (PI. XIV. fig. A).

Lotella marginata, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 19.
B. 7. D. 7-8 I 65. A. 62. V. 5.

Head of moderate length, two-ninths of the total, the caudal fin not included.
Eye very large, more than one-third of the length of the head, and equal to that
of the postorbital portion ; consequently the snout is short, though its length
much exceeds the width of the interorbital space. The maxillary extends only to
below the middle of the eye ; jaws with an outer series of distinctly larger teeth.
Barbel small.

Scales very small, about twelve or fourteen in a transverse series between the first
dorsal fin and the lateral line.

The first dorsal commences above the root of the pectoral, and has none of the rays
prolonged. The second dorsal and especially the anal is depressed in height along
the middle of its length. Pectoral shorter than the head, without snout, directed
upwards. The two outer ventral rays prolonged, the second (which is the longer)

^ Under tlie name of "Lotella maxillaris, n. s.," Dr. Bean described a specimen, 2§ inches long, obtained in 396
fathoms by the U.S. Fish Commission. It is an immature specimen, of which not even the genus or subgenus could
be determined with certainty {Proc. U.S. Nat. Mm., 1885, p. 241).

REPORT ON THE DEEP-SEA FISHES.

87

just reaching the vent. The distance between the vent and the root of the ventrals
equals the length of the head, without snout.

Light-coloured, with black margins to the vertical fins.

Habitat. — Pacific coast of south-western South America.

Near Magellan Strait, Station 305a; depth, 125 fathoms. Two specimens, 5 and
6^ inches long.

Near Magellan Strait, Station 306a ; depth, 345 fathoms. One specimen, 6 inches long.
Messier Channel, Station 307 ; depth, 140 fathoms. One specimen, 9 inches long.
Near Magellan Strait, Station 308 ; depth, 175 fathoms. Four specimens, 5| to 7
inches long.

Measurements : —

Total length, .

Length of the head,

Diameter of the eye.

Length of the pectoral tin,

Distance of the vent from the ventrals

Depth of the caudal peduncle.

105 lines.
22

8 „

15 „

16 „
24

Uraleptus, Costa.

UralejDtits maraldi.

Gculus maraldi, Eisso, Ichth. Nice, p. 123, pi vi. fig. 13.
Uraleptus maraldi, Costa, Faun. Napolit. Pesc, pi. xxxviia.

„ „ Giinth., Fish., vol. iv. p. 349.

,, ,, .Johnson, Ann. and Mag. Nat. Hist., 18G3, vol. x. p. 164.

Not very rare in the Mediterranean and off" Madeira, and apparently an inhabitant of
no great depths.

Physicuhis, Kaup.

Physiadus et Pseudophyci)<, Gthr.

In consequence of the discovery of several intermediate forms, a generic distinction
l:)etween Physiculus dalwigkii and Physiculus hacchus cannot be maintained ; and most
probably the transition from the perfectly developed, many-rayed ventral fin, to the
single filament of Phycis will be found to be so gradual, as to diminish the value of the
structure of this fin as a taxonomic character in these fishes. Besides the species enume-
rated here, others have been described (Physiculus hreviuscuhis. Rich. = Physiculus
hacchus, Forst, Physiculus barbatus, Gthv. = Phijsiculus pabnatus, Klunz.), but it is
not known whether they descend to the same depths as theii' congeners.

8R THE VOYAGE OF H.M.S. CHALLENGEE.

Physiculus dalwigkii

Phydadiis dalwigkii, Kaup, in Wiegm. Arch., 1858, p. 88.
,, „ Giinth., Fish., vol. iv. p. 348.

„ „ Jordan and Gilbert, Synopsis, p. 801. ^

I have three specimens before me, from Madeira, all of which have an exceedingly
narrow base to the ventral fin, which is composed of five rays only. The largest of these
specimens is only 10 inches long, and it is not known at what depth they were caught.

Physiculus haupi (PL XVII. fig. A).

Physicidm kaiqn, Poey, Report Cub., 1865, p. 186.

,, japonicus, Hilgendorf, Sitzungsb. naturf. Freunde Berlin, 1879, p. 80.

This species has constantly (as far as is shown by our specimens) a broader base to
the ventral fins than Physiculus dalwigkii, and they are formed of seven rays, of which
the longest may or may not reach the anal fin. The fin rays vary within proportionate
limits; they are D. 9-10 | 60-66. A. 60-70. There are thirteen series of scales between
the anterior dorsal and ■ the lateral line. The peduncle of the tail is shorter and less
slender than in the Madeiran form, but otherwise the two species are so similar as to
.scarcely deserve specific separation.

Habitat. — Poey obtained a specimen at Cuba, and Melliss two at St. Helena. These
differ in no respect from five examples found by the Challenger off Inosima in 345
fathoms, and 11 to 16 inches long.'

Physiculus peregrimis.

PgeiidopliTjcis peregrinus, Gtinth., Proc. Zool. Soc. Lond., 1871, p. 669.

With three rays in the ventral fins.

Since the discovery of the typical examjjle at Manado no other specimens have been
found. It has so much the characteristic appearance of a deep-sea fish that I cannot
hesitate to admit it here.

Phycis, Cuv.

All the species of this genus seem to descend habitually beyond the hundred fathom
line ; at any rate, the following have been recorded from deep water.

' See, with regard to this reference, .Jordan, Cat., p. 130.

2 Hilgendorf states as one of the characteristics of the Japanese form, that the leni,'th of the head is one-fifth of the
total length. This is not the case in our examples, in which the head forms nearly one -fourth of the total, as in
Physiculus dalwigkii.

REPORT ON THE DEEP-SEA PISHES. 89

Phycis hlennioides (Brlinn.).

Phycis hlennioides, Strom, Norsk. Vid. Selsk. Skr., 1881, p. 76 ; 1884, p. 35.
„ „ Collett, Nyt Mag. f. Naturvid., 1884, p. 83.

This species, which is not uncommou in the littoral parts of the European seas, is
reported by Strom and Collett from a depth of from 70 to 200 fathoms, from the
Norwegian coast.

Phycis chesteri.

Phycis chesteri, Goode and Bean, Proc. U.S. Nat. Mus., vol. i., 1879, p. 256.

„ „ Goode, ibid., vol. iii., 1881, pp. 337, 476; BuU. Mus. Comp. Zool., vol. x.,

1883, p. 204.

Known from numerous specimens, taken off the coasts of Massachusetts and New
England, in from 110 to 306 fathoms; the largest is nearly 10 inches long.

Phycis regius (Walb.).

Phycis regius, Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, pp. 337, 476; Bull. Mus. Comp.
Zool., vol. X., 1883, p. 204.

4- common species on the Atlantic coasts of North America, and recorded to have
been taken in from 142 to 155 fathoms, off the southern New England coasts.

Phycis americanus (Bl. Schn.).

Phycis chuss (Walk), Goode and Bean, BiiU. Mus. Comp. Zool., vol. x., 1883, p. 203.

♦ A common species on the Atlantic coasts of North America, and recorded to have

been taken in 143 fathoms, off the coasts of Massachusetts.

Phycis tenuis (Mitch.).

Phycis tenuis, Goode and Bean, Bull. Mus. Comp. Zool., x., 1883, p. 203.

Abundant on the Northern Atlantic coast of the United States, and once recorded
to have been taken in 304 fathoms, off the coast of Massachusetts.

Lasmonema, Gthr.

This group scarcely deserves generic separation from Phycis ; it was distinguished
only in order that we might be consistent in the employment of certain technical

(zool. CHALL. EXP. — PART LVII. — 1886.) Lll 12

90 THE VOYAGE OF H.M.S. CHALLENGER.

characters, by which the Gadidse have been divided. Of the four species known,
Lsemonema yarrellii and Lsemonema robustum probably reach to or below the depth of
100 fathoms, but this is not sufficiently indicated by their organisation. Lsemonema
brasiliense [Lsemonema hrefijile, Gthr.) is a shore fish.

Lsemonema harhatxdum.

Lsemonema barhatula, Goode and Bean, Bull. Mus. Comp. Zool., vol. x., 1883, p. 204.
B. 7. D. 5 I 63. A. 59. L. lat. 140. L. trans. ^.

The diameter of the eye is one-third of the length of the head. Length of the head
equal to the distance between the root of the ventrals and the anal.

Habitat. ^Beyeviil specimens were obtained in lat. 32° and 38° N., long. 73° and
78° W., by the United States Survey steamers at depths of from 225 to 312 fathoms.

Haloporphyrus, Gthr.
All the species of this genus belong to the deep-sea fauna.

Haloporphyrus guenthen (PI. XVIII. fig. A).

Haloporphyrus lepidion, Gtintli., Fish., vol. iv. p. 358.

,, ,, Johns., Ann. and Mag. Nat. Hist., 1862, vol. x. p. 166.

„ gilntheri, Giglioli, Nature, 1880, Jan. 1.

„ „ Vinciguerra, Ann. Mus. Civ. Genoa, vol. xviii. p. 558.

B. 7. D. 4 I 52-56. A. 49-52. P. 21. V. 6. L. lat. 210. Coec. phy. 15.

The diameter of the eye is one-sixth of the length of the head (in specimens
20 to 24 inches long). Caudal peduncle rather slender, its depth being two-thirds of
the distance between dorsal and caudal finsi Fifteen or sixteen longitudinal series of
scales between the anterior dorsal fin and the lateral line. The dorsal filament very
thin, thread-like.

Habitat. — This species has been obtained ofi" the coasts of Madeira and Portugal, and
also in the Mediterranean.

The figure of the head is of the natural size and taken from a Madeiran specimen,
24 inches long.

EEPORT ON THE DEEP-SEA FISHES. 91

Halojwrjjhyrus lepidion.

Gadus lepidion, Eisso, Ichth. Nice, p. 118, pi. xi. fig. 40.
Halojjorphyrus lepidion, Giglioli, loc. cit.

„ „ Vinciguerra, loc. cit., p. 554, Taf. iii.

D. (5)4 I 52. A. 46-48. V. 6. L. lat. 155-160. Ccbc. pyl. 10.

Eye very large, thrice or thrice and a half in the length of the head. Maxillary
extending beyond the middle of the orbit. Thirteen or fourteen series of scales between
the first dorsal fin and the lateral line.

Habitat. — Mediterranean.

I have recently obtained for the collection of the British Museum a specimen 10 inches

long from Nice, which is undoubtedly the true Gadus lepidion. As in the preceding and

following species, so in this specimen the scales between the first dorsal fin and the

lateral line are rather confused, but there are distinctly more than eleven series, which

jiumber is given by Vinciguerra as characteristic of this species.

Haloporphyrus eques, n. sp. (PI. XVIII. fig. B).

B. 7(8). D 4 I 56-62. A. 49-54. V. 7. L. lat. 180. Ca?c. pyl. 10-11.

The length of tlie head equals the distance between the root of the ventral fin and
the anal, and is rather less than one-fourth of the total (without caudal). The eye is
very large, one-third of the length of the head, longer than the snout, and nearly twice
the width of the interorbital space. Snout of moderate length, obtuse, with an
undulated series of pores in the prseorbital region running towards the extremity of
the snout. The mouth extends nearly to below the middle of the eye. Barbei half the
length of the eye. The caudal peduncle very slender, its depth being two-fifths of the
distance between dorsal and caudal fins. Fifteen or sixteen longitudinal series of scales
between the anterior dorsal fin and the lateral line. The first long dorsal ray is com-
pressed, moderately strong, extending backwards to the posterior fourth of the length of the
dorsal fin. The middle of the anal fin very conspicuously depressed. Caudal fin rounded,
with its basal rays extending for some distance along the peduncle. Pectoral fin as long
as the head without snout. The filamentous ventral ray, which, in fact, consists of two
rays free along their distal half, does not exceed in length the pectoral fin.

Brownish, with blackish fins ; orbit with a black ring ; the cavities of the mouth, gills
and abdomen black. Specimens of a much lighter colour (probably albinos) are not
scarce.

Young specimens (6 inches in length) do not differ essentially from older ones of
twice the length, but their eye is relatively still larger and the dorsal filament somewhat

^'Xy

92 THE VOYAGE OF H.M.S. CHALLENGER.

smaller. Numerous specimens were obtained by the "Knight Errant" in the Faroe
Channel, in 530 fathoms, the largest being 12 or 13 inches long, at Station 6, in August
1880, and Station 2, in August 1882.

I formerly believed that these specimens represented the younger stage of the large
specimen from Madeira (the only one known to me at the time) which I referred in
1862 to Risso's fish; but examples received at a later period convinced me that the
present species may be constantly, at all ages, distinguished by a comparatively larger eye
and shorter head. However, the three European species, viz., Haloporphyrus guentheri,
Haloporphyrus lepidion, and Haloporphyrus eques are most closely allied to each
VjOther.

Haloporphyrus inosimw, n. sp. (PL XX. fig. B).

B. 7. D. 5 I 60. A. 52. Ccec. pyl. 13.

This species is also very similar to Haloporphyi'us lepidion, but distinguished by
much smaller scales. The length of the head is conspicuously less than the distance
between the root of the ventral fin and the anal. Eye rather large, one-fourth of the
length of the head, equal to the length of the snout and more than the width of the
interorbital space. The rows of pores in the prseorbital region are present as in Halo-
porphyrus lepidion and Haloporphyrus eques, but the pores are much smaller. The
mouth scarcely extends to below the middle of the eye. Barbel nearly as long as the
eye. The caudal peduncle is rather slender, its depth being two-thirds of the distance
between dorsal and caudal fins. Scales very small, about twenty longitudinal series
between the anterior dorsal fin and the lateral line. The first long dorsal ray is rather
feeble, extending scarcely to the middle of the length of the dorsal fin. Middle of the
anal fin but little depressed. Caudal fin subtruncated. Pectoral fin three-fifths as long
as the head, equal in length to the filamentous ventral.

Brownish, with blackish fins ; the cavities of the mouth, gUls, and abdomen black.
-^ Habitat. — Several specimens, from 8 to 12 inches long, were obtained by the

fy^ -i-iuiyttoM-. — locveiiu speuimeuB, iron

1^ . Challenger at Inosima, in 345 fathoms.

Haloporphyrus ensiferus, n. sp. (PI. XIX. fig. A).

B. 7. D. 5 I 52. A. 46. V. 8. Ccec. pyl. 10.

Distinguished by the very broad and compressed dorsal ray. The length of the
head equals the distance between the root of the ventrals and the vent. Eye rather
large, two-sevenths of the length of the head, a little longer than the snout, and in
width much exceeding the interorbital space ; pores of the prfeorbital region very

REPORT ON THE DEEP-SEA FISHES. 93

small. Mouth comparatively narrow, only reachiug beyond the anterior margin of the
eye ; barbel much shorter than the eye. Caudal peduncle rather slender, its depth
being rather more than one-half of the distance between dorsal and caudal fins. Scales
very small, rather irregularly arranged, about eighteen longitudinal series between the
first dorsal fin and the lateral line. The long dorsal ray is strongly compressed, broad,
shaped like a blade of grass, and extending backwards to the posterior third of the
dorsal fin. It is so in three male specimens, but in a female the ray is much less
developed, scarcely extending beyond tlie anterior tliird of the dorsal fin. Middle of
the anal fin strongly depressed ; caudal fin subtruncated ; pectoral as long as the head
without snout, much shorter than the filamentous ventral fin, which, however, does not
reach the vent.

Brownish, fins blackish, the posterior dorsal and anal rays whitish ; cavities of the
mouth, gills, and abdomen black.

Habitat. — Four specimens, from 10 to 14 inches long, were obtained off the mouth of
the Rio Plata, at Station 320, in 600 fathoms.

Antimora.

Antimora, Giiiith., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 18.

Body elongate, covered with small scales. Upper part of the snout produced into a
pointed projection. A separate caudal ; two dorsal fins, the first with four or five rays ;
one anal, with a deep depression along the middle. Ventrals narrow, composed of six
rays. Jaws with bands of villiform teeth ; vomerine teeth in a small roundish patch ;
none on the palatine bones. Muciferous channels on the side of the head well
developed ; bones of the cranium wanting in solidity. Vent at the end of the abdominal
cavity. Chin with a barbel. Branchiostegals seven; pseudobranchise none. Pyloric
appendages long, in moderate number.

Deep-sea fishes descending to greater depths than the allied genera of Salilota and
Haloporphyrus.

Antimora rostrata (PI. XVI. fig. A).

Haloporphyrus rosfratus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 18.
B. 7. D. 4 I 51-56. A. 38-39. V. 6. L. lat. 140. L. transv. ca. 1 0/ a:. Coec. pyl. 13. -^

This species is readily distinguished by the peculiarly produced snout, which forms a
short, triangular, pointed lamina, sharply keeled on the sides, and overhanging the cleft
of the mouth.

The head is rather short, broad posteriorly, half as long as the distance between

/

94 THE VOYAGE OF H.M.S. CHALLENGEE.

ventral and anal fins. Eye round, rather large, its diameter one-fonrth of the length of
the head, less than that of the snout, and nearly equal to the width of the flat inter-
orbital space. Mouth wide, the maxillary extending nearly to below the hind margin
of the eye. Teeth in both jaws in narrow villiform bands ; a small group of teeth on
the vomer. Posterior extremity of the maxillary not much dilated. Nostrils close
together ; the posterior are wide, semicircular openings, the anterior narrower and round.
The vent is rather nearer to the end of the operculum than to the root of the caudal.

The entire head (even the gill-membrane and the foremost part of the snout) and the
body are covered with small cycloid scales, of which only a few have been preserved ;
there are about ten in a transverse line between the first dorsal fin and the lateral line.

The greater part of the dorsal and anal fins are covered with scales. The first dorsal
is subcontinuous with the second, and the first ray is produced into a filament about as
long as the head. The second dorsal and anal fins are rather low ; the latter so much
depressed in the middle as to present the appearance of a double anal. The free portion
of the tail is narrow, terminating in a comparatively small caudal fin, which is truncated
behind. Pectoral pointed, the upper rays being the longest ; it is as long as or longer
than the head exclusive of the snout. The two outer ventral rays prolonged as
two filaments ; the second being twice as long as the first, and not extending as far
back as the pectoral.

Black ; cavity of the mouth, gills, and abdomen deep black.

Habitat. — Deep-sea, midway between the Cape of Good Hope and Kerguelen Island ;
east of the mouth of the Eio de la Plata.

Near Marion Island, Station 146; depth, 1375 fathoms. One specimen, 18^ inches
long.

Off Monte Video, Station 320 ; depth, 600 fathoms. One specimen, 24 inches long.

Antimora viola (PI. XV.)

Haloporplujrus viola, Goode and Bean, Proc. U.S. Nat. Mus., vol. i., 1879, p. 257 ; vol. iii., 1881,
p. 476 ; BuU Mus. Comp. Zool., vol x., 1883, p. 206 ; Amer. Jonrn. Sci.
and Arts, vol. xvii., 1879, p. 41.

Antimora viola, Jordan, Cat. Fish. N. Amer., p. 129.

This fish is very closely allied to Antimora rostrata, but clearly a distinct species, if
the following characters should prove to be constant.

1 S

B. 7. D. 4-5 I 53-55. A. 40. V. 6. L. lat. 145. L. transv. — Coec. pyl. 16.

Head rather elongate and pointed, its length being much more than one-half of
the distance between ventral and anal fins. Vent midway between the root of the
caudal and the eye. Eye large, oval, its horizontal longest diameter being rather more

REPORT ON THE DEEP-SEA FISHES. 96

than one-fourth of the length of the head, as long as the snout, and exceeding the width
of the interorbital space. Violet.

The single specimen from which these characters are taken is 16 inches long, and was
obtained by the U.S. Fish Commission in lat. 43° 41' N., and long. 59° 15' W.

But this species seems to be abundant in the deep sea off the Atlantic coasts of the
United States, numerous examples having been taken in depths of from 30G to 1242
fathoms. Greatest length recorded, 1 8 inches.

Salilota.

Body oblong, covered with very small scales. Head thick, but rather compressed.
A separate caudal ; two dorsal fins and one anal. Ventrals with broad base, composed of
several (eight) rays. Abdominal cavity extending far behind the vent. Villiform teeth
of equal size in the jaws and on the vomer; none on the palatines. The first dorsal
with about nine rays. Chin with a barbel. Pyloric appendages very long, of moderate
number.

This fish differs so strikingly from the typical Haloporphyrus, with which I at first
associated it, that its separation into a distinct genus seems to me justified. It forms a
passage to Lota, from which it difiers by an eutu-ely different form of the head. It is
not a deep-sea fish, and ought to have been included in the shore series.

Salilota australis (PI. XVII. fig. B).

Halopliorphyrus australis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 19.

D. 9 I 50-52. A. 53. V. 8. Ccec. pyl. 17.

The length of the head is one-fourth of the total (without caudal), and about twice
as long as the distance of the ventrals from the anal. The depth of the body is two-fifths
of the total. Snout obtuse, rounded, with the upper jaw overlapping the lower, as long as, or
rather longer than the eye, the diameter of which is one-fourth or two-ninths of the length
of the head. The maxillary extends somewhat behind the middle of the eye. Teeth villi-
form, forming bands. A small semicircular patch of similar teeth in the middle of the head
of the vomer. Barbel shorter than the eye. Interorbital space flat, wider than the eye.
There are about eighteen longitudinal series of scales between the anterior dorsal and the
lateral line. The first dorsal fin has no prolonged rays, and is not higher than the second,
situated behind the root of the pectoral. The second dorsal and and have the margin
somewhat emarginate, and terminate close to the caudal. Vent situated below the first
dorsal. Caudal slightly rounded. The length of the pectoral fin is two-thirds of that of

96 THE VOYAGE OF H.M.S. CHALLENGER.

the head. Outer ventral ray bifid, slightly prolonged, reaching to the vent. Uniform
brown, vertical fins with a blackish margin.

Habitat. — Puerto Bueno ; Magellan Strait.

Off Cape Virgins, Patagonia, Station 313; depth, 55 fathoms. One specimen, 18^
inches long.

Puerto Bueno, 9th January 1876. One specimen, 11 inches long; one specimen, 12
inches long.

Between Cape Virgins and Falkland Islands, Station 314; depth, 70 fathoms. One
specimen, 6 inches long.

^ Molva, Nilss.

Molva molva, L.

Mulva vuhjaris (Flem.), CoUett, Nyt Mag. f. Naturvid., 1884, p. 84.
„ „ Lilljeb., Sverig. och Norg. Fisk., p. 131.

Collett states that on the Norwegian coast young examples of the Ling are rarely
found at a less depth than 100 fathoms; and according to Lilljeborg the largest are
caught at a depth of from 80 to 150 fathoms.

Molva ahyssorum, Nilss.

Molva byrlelange (Walbaum), Strom, Norsk. Vid. Selsk. Skr., 1884, p. 35.
„ „ Collett, Nyt Mag. f. Naturvid., 1884, p. 84.

„ ,, LUljeb., Sverig. och Norg. Fisk., p. 139.

This species descends to a still greater depth than the Common Ling, and is abundant
between 100 and 300 fathoms.

Onv^, Kisso.

This genus is represented in the North Atlantic from the shore-line to a depth
exceeding: 1000 fathoms.

"&

Onus macrophthahnus.

Motella macrojMJial/na, Giintli., Ann. and Mag. Nat. Hist., 1867, vol. xx. p. 288, pi. v. fig. b.

D. 55. A. 55. P. 17. V. 5.

Barbels three. The length of the head is one-fourth of the total (without caudal).
The diameter of the eye is one-fourth of the length of the head, as long as the snout, and
much longer than the interorbital space is wide. The maxillary reaches the hind margin
of the orbit. Both jaws with teeth unequal in size, some being enlarged and canine-like.

REPORT ON THE DEEP-SEA FISHES. 97

Vent nearer to the snout than to the end of the anal. The anterior ray of the first dorsal
about as long as the eye. Back with narrow brownish cross-bars.

This species is known only from a single example, 3 inches long, obtained in 80 or 90
fathoms, near the Hebrides. Dr. Liitken ' gives it as his opinion that this represents the
young of his Motella mecUterranea (L.). But I have never seen a Mediterranean speci-
men of the same size and with equally large eyes. Also Hr. Collett' would refer it rather
to a species which he characterises by 62 dorsal, 21 pectoral, and 8 ventral rays !

Onus carpenteri (PI. XLII. fig. D),

Motella macrophthalmu, Gunth., Ann. and Mag. Nat. Hist., 1874, vol xiii. p. 139 (not 18G7).
D. 49. A. 45. P. 23. V. 6.

Barbels three. The length of the head is two-ninths of the total (without caudal);
the diameter of the eye two-ninths of the length of the head, as long as the snout and
longer than the interorbital space is wide. The maxillary reaches to a little behind the
hind margin of the orbit. Both jaws with teeth unequal in size, some being enlarged
and caniue-like. Vent much nearer to the snout than to the end of the anal. The
anterior ray of the first dorsal fin about as long as the eye. Coloration uniform.

One specimen only is known, 4^ inches long, obtained during the cruise of H.M.S.
"Porcupine," in 180 fathoms, between Shetland and Faroe. I formerly regarded this
specimen as representing a more advanced stage of growth of Omis macrophthalmus, an
opinion fully in accord with the characters given above. But Dr. Liitken, in a recent
paper on the species of this geuus,^ has drawn attention to difi'erences in the paired fins
which, if they are of specific value in this genus, indicate the distinctness of this
specimen from all the species known to me or described by Dr. Liitken. It is named
after Dr. Carpenter, whose memory will ever be associated with the " Porcupine " and
the succeeding British Deep-Sea Expeditions.

Onxis 7'einhardti (PI. XIX. fig. B).

Motella reinhardi* Collett, Forbandl. Vidensk. Selsk. Christ., 1878, p. 83.

„ „ Liitken, Vid. Meddel nat. Foren. KjVbenhavn, 1882, p. 236.

Onos reinhardi, Collett, Norsk. Nordli. Exped. Fisk., p. 131, pi. iv. fig. 34.

D. 53-59. A. 43-48. P. 22-24. V. 8.

Barbels three. The length of the head is contained four and one-fourth times in the
total (without caudal), the diameter of the eye four times and two-thirds or five times in

1 Vid. Meddel. iiat. Foren. Kj^ihenhavn, 1882, p. 244.

2 Nyt Mag.f. Naturvid., 1884, p. 93.

3 Vid. Meddel. nat. Foren. Kjipbenham, 1882, p. 228.

4 This fish remained undescribed, and the name merely a MS. term, until Collett undertook its examination
in 1878.

(ZOOL. CHALL. E.XP. — PART LVII. — 1886.) ^-" '-^

08 THE YOYAGE OF H.M.S. CHALLENGER.

the length of the head ; it is shorter than the snout, equal to, or less in length than, the
width of the interorbital space. The maxillary scarcely extends to the hind margin of the
eye. Both jaws and the vomer with an outer series of larger teeth. Vent nearer to the
root of the caudal than to the snout. The anterior ray of the first dorsal fin rather
longer than the eye. Coloration uniform.

Habitat. — Several specimens, the longest of which is 12 inches long, were obtained by
the " Knight Errant " in the Faroe Channel, at Station 8 (August 1880), in 540 fathoms,
and at Stations 8 and 9 (August 1882), in 608 and 640 fathoms.^ At a similar depth
(658 fathoms) the species was found by the North Atlantic expedition in the open sea west
of Bear Island. Other specimens came from the coast of Greenland.

Onus septentrionalis.

Motella septemtrionalis, Collett, Ann. and Mag. Nat. Hist., 1875, vol xv. p. 82 ; Norg. Fisk.,
p. 117, pi. ii.; Forhandl. Vidensk. Selsk. Christ., 1880, p. 68.

Orms septemtrionalis, Collett, Norsk. Nordh. Exped., Fisk., p. 138, pL iv. figs. 35, 36; Nyt
Mag. f. Naturvid., vol. xviii., 1884, p. 86.
„ „ Strom, Norsk. Vidensk. Selsk. Skriv., 1881, p. 77.

From the coast of Norway in from 20 to 50 fathoms, and reported by Strom to have
been found once in 150 fathoms ; extending westwards to the coast of Greenland.

Onus ensis (Reinh.).

The typical specimens are from the coast of Greenland ; and it would appear from a
short note" that the same fish has been found at a depth of 1106 fathoms, by the U.S.
Fish Commission, in lat. 39° 41' N., long. 69° 20' W.

Onus cimhnus, L.

Onus cimbrius, Goode and Bean, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 476; BuU. Mus.
Comp. Zool., vol. X., 1883, p. 207.

Not rare on the northern coasts of Europe and America, and reported from 178
fathoms by Brown Goode.

Brosmius, Cuv.
Brosmtus hrosme, Miill.

Brosmius brosme, Giintk, Proc. Eoy. Soc. Edin., 1882, p. 680.
„ „ Lilljeb., Sverig. och Norg. Fisk., vol. ii. p. 202.

The Torsk lives habitually in deep water, in from 30 to 120 fathoms; one adult
example was obtained by the " Knight Errant" in the Faroe Channel (August 11, 1880),
in 530 fathoms.

' These specimens were erroneously referred to Motella macrophthalnm in Proc. Roy. Soc. Edin., 1882, p. 680.
2 Gill, Proc. U.S. Nat. Mus., vol. vi., 1884, p. 259 {Onus rtifus).

REPORT ON THE DEEP-SEA FISHES. 99

Cliiasmodus, Johns.

One species only is known.

Chiasmodus niger.

Ckiasmodus niger, Johns., Proc. Zool Soc. Lond., 1863, p. 408.'
„ „ Giinth., Fish., vol v. p. 435.

„ „ Carter, Proc. Zool. Soc. Lond., 1886, p. 3.5, pi. ii.i

„ „ Giinth., Ibid.

„ „ Jordan and Gilbert, Synops. Fish. North Amer., p. 810.

The first specimen, only 2f inches long, was obtained at Magdalena (Madeira), at a
depth of 312 fathoms, in the year 1850, by Lowe, who, however, omitted to give a
description of it. The species was rediscovered twelve years later at the same locality
by Johnson, who recognised it as the type of a distinct genus. The thii-d specimen,
6^ inches long, the largest known at present, was picked up from the surface, near the
island of Dominica. A fourth example, 2^ inches long, in no point differing from the
preceding, except that it has lost the larger front teeth, was obtained by the Challenger,
in Mid-Atlantic, at Station 107 (August 26, 1873), in 1500 fathoms. Finally, Jordan
and Gilbert mention the capture of this fish off the coast of Massachusetts.

Family OphidiiD/E.
Barathrodemus.

Barathrodemus, Goode and Bean, Bull. Mus. Coinp. ZouL, vol.'x., 1883, p. 200. -^

Caudal free from the other vertical fins. Pectoral without detached rays. Ventrals
reduced each to a single bifid ray, close together, inserted under the middle of the
operculum. Body elongate, much compressed, covered, like the head, with small thin
scales. Head compressed ; snout long, swollen, overlapping the jaws ; mouth moderate.
Villiform teeth in the jaws, on the vomer and palatines. Barbel none. Brauchiostegals
eight ; pseudobranchise none. Lateral line indistinct.

One species is known.

1 The specimen de.scribed in this paper was first submitted to me by Mr. Carter, who begged me to give liim my
opinion on it ; the figure was also made under my direction.

' A specimen of some aUied deep-sea fish, and noticed in Proc. U.S. Nat. Mm., 1884, p. 259, under the name of
Bassozetus normalis, is at present not better kuown than if it had escaped the dredge of the U.S. Fish Commission.

100 THE VOYAGE OF H.M.S. CHALLENGER.

Barathrodemus manatinus.

Barathrodemus manatinus, Goode and Bean, loc. cit.

B. 8. D. 106. A. 86. C. 9. P. 18-20. V. |. L. transv. ca. 34 (above vent).

Habitat. — Two specimens, 6^ inches long, were obtained by the U.S. steamer "Blake,"
in lat. 33° 35' N., long. 76° 0' W., at a depth of 647 fathoms.

Neobythites.
Neobythites, Goode and Bean, Proc. U.S. Nat. Mus., vol. viii., 1886, p. 600.

Body elongate, compressed, covered with small scales ; lateral line indistinct. Head
not compressed, covered with scales. Eye of moderate size. Vertical fins united ;
ventrals each reduced to a bifid filament, inserted behind the humeral symphysis, and
somewhat distant from each other. Snout overlapping the mouth, without barbels.
Bands of villiform teeth in the jaws, on the vomer and palatine bones. Operculum with
a long spine. Eight branchiostegals ; air-bladder present ; pseudobranchise small.
Pyloric appendages 0 to 20.

This genus has been distinguished by me for some time, but the manuscript name
which I proposed for it, Tetranematopus, was unfortunately introduced by me into the
literature without diagnosis, so that it has to give way to Neobythites. I failed to
recognise the latter, as it was characterised by single-rayed ventral fins, until Mr. Goode,
on inquiry, kindly informed me that the genus to which he had given this name has bifid
ventral rays, as, indeed, he had stated in the description of the species.

r. -/^'^

\f\C<-^ Neobythites grandis (PI. XXI. fig. A).

Sirembo grandis, Giinth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 437.

Head rather short and broad, with obtuse snout overlapping the lower jaw. Eye
small, about one-third of the length of the snout and one-eleventh of that of the head.
Mouth rather wide, the maxillary extending to behind the eye ; barbels none. Teeth
of the jaws, vomer, and palatine bones in vUliform bands. The vomerine teeth form
a triangular patch, much broader than long ; the width of the palatine band exceeds
that of the intermaxillary. A deep groove in the skin descends from the anterior
nostril towards the maxillary, and reascends towards the median line of the extremity
of the snout, cutting ofi" an anterior lobe, as in some Scisenoids. Several pores, leading
into the muciferous system, are hidden in the groove ; a few small open pores near the
symphysis of the mandible. Nostrils gaping, oval openings, of which the anterior is
surrounded by a membranous wall. Preeoperculum crescent-shaped, without any

REPORT ON THE DEEP-SEA FISHES. 101

armature ; operculum with a strong spine above. Distance of the vent from the root of
the pectoral more than the length of the head.

Scales minute ; also the entire head, even the space between the nostrils, covered
with minute scales. Lateral line indistinct for the greater part of its course.

The dorsal fin is, like the anal, enveloped in a thick, scaly skin. It commences
with short rays above the middle of the pectoral fin. The pectoral is rounded, broad,
and remarkably short, about half as long as the head. Ventrals inserted below the
angle of the prseoperculum. Each ventral filament is bifid, the inner part being the
longer.

Brown ; darker behind, lighter in front. Fins blackish. Cavity of the mouth
grey, peritoneum black.

Total length, 29i inches ; length of the head, 5f inches ; length of ventral filament,
3 inches; distance of the vent from the snout, 12|^ inches. This specimen is the largest
deep-sea fish obtained by the Expedition.

Habitat. — South of Yedo, near Yokohama, Japan, Station 237 ; depth, 1875
fathoms. One specimen.

Without causing more injury to the unique specimen than is consistent with its
preservation, the following points could be made out as regards its abdominal organs.

The oesophagus is provided with about ten deep, parallel folds, some of which
coalesce where the oesophagus passes into the stomach, forming then only seven deep
and broad folds. The stomach is short, without ctecal prolongation behind, simply bent
towards the right at its posterior extremity, and passing immediately into the intestine.
A duodenal division cannot be distinguished. The walls of the stomach are very thick,
and strengthened by an outer stratum of longitudinal muscular fascicles. Externally
the pylorus is marked by a shght constriction, pyloric appendages being absent.
Internally the pyloric passage is indicated by a very low circular fold, on which the
longitudinal folds of the mucous membrane of the stomach terminate, and behind which
the villosities of the intestinal tube begin. I do not recollect any other fish in which
the mucous membrane of the intestine shows an equally developed villous texture.
The villosities are long, coarse, and densely packed, transversely lamellar or pointed,
becoming lower in the vicinity of the rectum. Rectum short, separated by a deep
circular valvular fold from the upper part of the intestine ; its mucous membrane has a
reticulated surface. The intestinal tract makes one and a half convolutions, and the
mesenteric blood-vessels are singularly wide and thick-walled.

The liver is very large, occupying about one-third of the abdominal cavity, viz., the
whole of its left side, extending nearly to its hinder end. Its anterior transverse
portion bends over into a very short and narrow right lobe. The gall-bladder is large,
entirely separate from the liver, sending a narrow duct into the intestine a considerable

102 THE VOYAGE OF H.M.S. CHALLENGEE.

distance below the pylorus. Attached to its dorsal convexity is the spleen, wliich is
a large, compact, kidney-shaped gland.

The ovary is enclosed in a sac of very firm texture, and situated between the rectum
and the kidney. It was much contracted in our specimen, and without ova. A strong
ligament extends from its anterior ventral end to the level of the anterior end of the
gall-bladder, where it coalesces with the mesentery ; another long ligament, starting
more to the left of the ovarian sac, fixes the organ to the air-bladder.

The air-bladder is large, firmly attached to the dorsal wall of the abdomen. Ex-
ternally it appears to be simple, but it consists of two divisions, one behind the other,
separated by a complete elastic transverse septum. The anterior division is the shorter,
and possesses thinner tunics, which collapse when divided by the knife. The inner
silvery tunic, as well as the fibrous one of the posterior division, is much thicker. A
large vaso-ganglion, covered by the inner • tunic only, occupies the back of the cavity.
The vessels of this rete mirabile unite into a bundle of the thickness of a goose's
quill, which enters this division in about the middle of its length, and is loosely
stretched, without other attachment, to the end of the bladder where it makes its exit.

Neobythites macrops, n. sp. (PL XX. fig. A).

Head oblong, as deep as broad, the obtusely rounded snout overlapping the lower
jaw. Eye rather large, two-ninths of the length of the head, its long diameter being
equal to the length of the snout and to the width of the flat, scaly, interorbital space. The
maxillary extends somewhat behind the eye. Vomerine teeth in a triangular patch or
/\-shaped band; palatine teeth in a long band, which tapers behind, and is in the middle
as broad as the intermaxillary band. Preeoperculum with two short spines ; one at the
angle, the other somewhat above it ; both jiointing backwards. Opercular spine rather
strong, finely pointed. The upper part of the head is covered with small scales nearly
to the extremity of the snout ; simUar small scales cover the skin between the two rami
of the mandible. There are eight or nine scales in a transverse series between the first
dorsal ray and the lateral line. The vertical fins are rather low, the dorsal beginning
behind the root of the pectoral. The distance between the vent and root of the ventrals
equals the length of the head. Pectoral fin as long as the postorbital portion of the head.
The ventrals are bifid, the inner filament being the longer ; they are inserted nearly
opposite to the angle of the prseoperculum, somewhat distant from each other, and do not
extend so far backwards as the pectorals. Brownish-grey, irregularly spotted with brown ;
six or seven large deep-black blotches on the dorsal fin.

Habitat. — Off the Philippine Islands, Station 210 ; depth, 375 fathoms. One
specimen, 8| inches long.

The firm structure of the bones of the skull, the moderate size of the eye, and the

REPORT ON THE DEEP-SEA FISHES. 103

variegated coloration seem clearly to indicate that this fish is not an inhabitant of very
great depths, and, perhaps, does not penetrate beyond the depth mentioned.

A second smaller specimen is so similar to the other, that no distinctive specific
characters can be pointed out ; it is not, however, in a good state of preservation. It is
of a nearly uniform reddish colour, finely punctated with greyish on the back, and white
below.

Habitat.— OS Matuku, Fiji Islands, Station 173a; depth, 310 fathoms. One
specimen, 6^ inches long.

The stomach of this species is prolonged into a distinct csecal sac ; the pylorus is
surrounded by a ring of extremely short appendages, and others equally short occupy in
a double series the mesenteric line of the uppermost part of the intestine. These pyloric
appendages are altogether twenty in number.

Neobythites ocellatus, n. sp. (PL XXL fig. B).

Head compressed, deeper than broad, the obtusely rounded snout overlapping the
lower jaw. Anterior part of the head with wide muciferous cavities. Eye rather large,
as long as the snout, and one-fourth of the length of the head. Interorbital space
convex. The maxillary extends somewhat behind the eye. Prseoperculum with an
obtuse spine above its angle, hidden below the skin. Opercular spine slender, very con-
spicuous. Vomerine teeth a subquadrangular patch, as broad as long, with the posterior
corners produced. The upper part of the head is covered with small scales to between
the eyes. Chin naked. Scales small and very thin, in seven or eight longitudinal series
between the dorsal fin and lateral line. Vertical fins of moderate height, the dorsal
beginning behind the root of the pectoral. The distance between the vent and root of
the veutrals equals the length of the head. Pectorals rather longer than the postorbital
portion of the head. The ventrals are inserted nearly opposite to the angle of the
praeoperculum a little distant from each other, and do not quite extend so far backwards
as the pectorals; they are bifid, the inner filament being the longer. Body light
brownish, marbled with darker. A large black white-edged ocellus anteriorly on the
dorsal fin, a second larger one at some distance behind, a third is but slightly indicated.

Habitat.— Oe Pernambuco, coast of Brazil, Station 122 ; depth, 350 fathoms. One
specimen, 3f inches long.

Neobythites gillii.

Neobythites gillii, Goode and Bean, Proc. U.S. Nat. Mus., vol. viiL, 1886, p. 600.
The eye is large, contained three and two-third times in the length of the head, and
one and' one-half times in that of the snout. Mouth large, extending to behind the

104 THE VOYAGE OF H.M.S. CHALLENGER.

eye; patch of vomerine teeth broadly V-shaped, with a circular bunch at the angle.
Scales of moderate size, seven rows between the origin of the dorsal fin and the lateral
line. Length of the pectoral fin equal to two-thii'ds of that of the head; ventral
reaching nearly to the vent. The distance of the root of the ventral from the vent
equals the length of the head. Coloration a light yellowish, with a series of irregular
brown blotches above the lateral line, two being much darker, extending up on the
dorsal fin, the largest about midway between head and tail.

Habitat. — A single specimen, 3^ inches long, was obtained by the U.S. Fish
Commission, in lat. 28° 36' N., and long. 85° 33' W., at a depth of 111 fathoms.

Catsetyx, n. gen.

Body compressed, elongate, covered with very small and thin scales ; lateral line
indistinct, interrupted. Head oblong, with somewhat pointed, snout, covered with very
small scales, only the anterior part of the snout naked ; bones of the head rather firm,
but with the muciferous system well developed, the canals having wide openings along
the infraorbital, and on the lower limb of the prseoperculum. Eye rather small.
Nostrils far apart, the posterior in front of the eye and the anterior at the extremity of
the snout. Operculum with a spine behind, no other armature on the head. Snout not
swollen, but the upper jaw slightly overlapping the lower ; barbels none. Mouth wide.
Bands of villiform teeth in the jaws, on the vomer and the palatine bones ; a series of
larger teeth along the sides of the lower jaw. The tail is not much attenuated.
Vertical fins confluent ; ventrals close together, reduced to a pair of fine simple filaments,
and inserted somewhat behind the isthmus, below the middle of the operculum.

Gills four, with short broad gill-rakers and well-developed laminae. Pseudobranchise
none. Branchiostegals eight. Pyloric appendages.

Catsetyx messieri (PI. XXIII. fig. B).

Sirembo messieri, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 19.

D. 105. C. 12. A. 75. P. 24.

The height of the body below the origin of the dorsal fin is rather more than one-
third of the distance of the extremity of the snout from the vent, the length of the head
rather less than one-half, the vent being nearly equidistant from the snout and root of
the caudal fin. Head deeper than broad. Eye without orbital fold, one-sixth of the
length of the head, two-thirds of that of the snout and less than the width of the flat
interorbital space. The maxillary is dilated behind, extending behind the eye ; labial
folds well developed. The vomerine teeth form an open y-shaped band and are stronger
than those of the maxillary. The vertical fins are completely confluent, but as the

EEPORT ON THE DEEP-SEA FISHES. 105

termination of the tail is comparatively broad, the rays starting from the end may be
regarded as the caudal portion. All the fin rays are thin and closely set, enveloped in a
broad basal membrane, so that it is difficult to ascertain their number without dissection.
Origin of the dorsal fin midway between occiput and vent. Anal fin commencing
immediately behind the vent. Pectoral fin, with broad fleshy base, as long as the post-
orbital portion of the head. The ventrals do not extend so far backwards as the
pectorals, and the distance between their root and the vent is much more than the
length of the head.

Uniform brown with black fins.

Habitat— OS Middle Island, Messier Strait, Station 306a; depth, 345 fathoms.
One specimen, 8 inches long.

PteridiuTTi (Scopoli).

Head and body compressed, covered with very small scales, only the upper part of
the head and the snout being naked. The body is moderately elongate, the tail but
little attenuated. Snout obtuse, not swollen, with the jaws even in front, and with the
mouth obliquely ascending. Bones of the head firm, the muciferous canals narrow.
Eye small. Operculum with a short spine behind; praeoperculum with two short
projections near the angle. Barbels none. Bands of villiform teeth in the jaws and
an open V-shaped band on the vomer; some sUghtly enlarged teeth along the inner
series of the mandible and on the vomer; palatine teeth none. Vertical fins con-
fluent; ventrals close together, reduced to a pair of fine simple filaments, and inserted
somewhat behind the isthmus, below the middle of the operculum. Lateral line inter-
rupted. Gills four ; pseudobranchise none. Branchiostegals eight. Pyloric appendages
two.

Only one species is known.

Pteridium atrum (Eisso).

Very scarce in the Mediterranean, and admitted here for comparison with the allied
bathybial genera. Probably it also is an inhabitant of considerable depths, but nothing
is known on this point. Having now obtained a specimen 3| inches long, but m a
somewhat desiccated condition, I am enabled to correct my former diagnosis,' which was
drawn up from Filippi and Verany's description. The lateral line is rather indistinct,
interrupted, and the fact that the ends of the two portions overlap each other, gave rise
to the statement that the line was double along a portion of the tail.

' Fish., vol. iv. p. 375.

(ZOOL. CHALL. EXP. — PAKT LVII. — 1886.)

106 THE VOYAGE OF H.M.S. CHALLENGER.

Pteroidonus, n. gen.

/ The lower pectoral rays are incompletely united with the upper part of the fin and arf>
prolonged. Body elongate, compressed, covered with small scales; lateral line incomplete,
close to the dorsal profile. Head oblong, thick, covered with scales. Eye small.
Vertical fins united, but the narrow caudal projecting beyond the short anal and dorsal
rays. Ventrals reduced to a simple filament, inserted behind the humeral symphysis,
and somewhat distant from each other. Snout broad with rounded profile, including
the lower jaw, without barbel. Mouth wide ; bands of villiform teeth in the jaws, on
the vomer and palatine bones. Operculum with a straight spine ; pra^operculum armed.
Eight branchiostegals. Gill-laminse rather short ; gill-rakers rather long, lanceolate and
widely set ; pseudobranchis^none.
A true deep-sea form. ^ V

Pteroidonus quinquarius, n. sp. (PI. XXII. fig. B).

B. 8. D. 99. A. 87. C. 5. V. 1. P. 15 | 5. L. transv. ca. 35 (above vent).

Body elongate, compressed, its depth being less than the length of the head, which
equals the distance between the vent and root of pectoral fin. The tail tapers almost to
a point. Head not much deeper than broad, its depth being equal to the length of its
postorbital portion ; it is flat above, the interorbital space being more than twice as
l)road as the eye. Eye small, without orbital fold, much shorter than the snout, and
about one-seventh of the length of the head ; it is lateral, but situated immediately below
the upper profile of the head. No spines about the orbit. Nostrils rather distant from
each other, open ; the posterior, the larger, immediately in front of the upper part of the
eye, the anterior close to the end of the snout.

Snout broad, rather depressed, overlapping the lower jaw. Mouth wide, somewhat
oblique, the much dilated posterior extremity of the maxillary extending backwards
beyond the orbit. Prseorbital region narrow ; intermaxillary styliform. Teeth in viUi-
form bauds, the bands of the vomer and palatines very narrow ; vomerine band A-shaped.
Prseoperculum with a rounded angle which is armed with three very short and weak
spines ; opercular spine moderately strong and straight.

The bones of the head are thin, with shallow muciferous cavities. Nearly the entire
head, even the dilated extremity of the maxillary and the giossohyal region, are covered
with small scales. GiU-membranes entirely separate.

The dorsal fin commences at a short distance behind the root of the pectoral, is rather
low, the rays being enclosed in a scaly skin at the base, and has its last and shortest
rays connected with the caudal by membrane. The anal is very similar to the dorsal,
but lower. The length of the very narrow caudal is two-fifths of that of the head.

REPORT ON THE DEEP-SEA FISHES. 107

The pectoral fin has a broad base, is elongate, with rounded posterior margin, and as
long as the head without snout. The five detached rays are somewhat stronger than the
other rays ; they form at the base one continuous series with the remainder of the fin, and
therefore do not seem to possess a separate action. The uppermost ray is the longest, not
quite twice as long as the fin, the others gradually decreasing in length. The ventral
fins are very feeble simple filaments, only half as long as the pectoral, somewhat distant
from each other, and inserted opposite to the hind margin of the prseoperculum.

The scales are small, thin, smooth, adherent. The lateral line is a continuous tract,
not covered by scales, running parallel to, and close to, the dorsal profile, and disappearing
in the posterior third of the tail ; it is separated from the dorsal fin by about six
series of scales.

The colour was probably pink, with black vertical fins ; cavity of the mouth and gills
black.

Habitat. — Japan, Station 235; depth, 565 fathoms. One specimen, \i\ inches long.

Dicrolene.

Dicrolene, Goode and Bean, Bull. Mus. Comp. ZooL, vol. x., 1883, p. 202.

The lower pectoral rays are separate and much produced. Body elongate, moderately
compressed, covered with small scales. Lateral line incomplete, close to the dorsal
profile. Head somewhat compressed, covered with scales. Eye large. A small separate
caudal fin much prolonged. Ventral fins close together, each composed of a single bifid
ray. Snout short ; jaws nearly equal in front ; barbel none. Mouth and dentition as
in Pteroidonus. Operculum with a straight spine. Seven branchiostegals. Gill-laminse
of moderate length; gill-rakers rather long, not numerous; pseudobranchiie none.
Pyloric caeca few, rudimentary.

One species is known.

Dicrolene intronigra.

Dicrolene intronigm-, Goode and Bean, loc. cit.
B. 7. D. 100. A. ca. 85. C. 6 or 7. V. 1 I 1. P. 19 I 7-8. L. transv. ca. 27 (above vent).

Head with supraorbital spines; several strong spines on the prseoperculum. Eye
one-fourth as long as the head and as wide as the interorbital space. Upper detached
pectoral ray one-third of the length of the body, and about thrice as long as the fin.

Habitat.— ^&\Qm\ specimens (the size is not stated) were obtained by the U.S.
steamer " Blake"; in lat. 33° 40' N., long. 76° 0' W.; in 464 and 647 fathoms.

108 THE VOYAGE OF H.M.S. CHALLENGEE.

Mixonus, n. gen.

I have long hesitated to describe the following fish under a distinct generic name.
The specimen is small, unique, and not in the best state of preservation, so that several
of the characters assigned here to the genus may have to be amended when other
specimens are discovered. Its pertinence to either Pteroidonus or Dicrolene seems to
be doubtful on account of the difi"erence in the shape of the head.

The lower pectoral rays are free, not united by membrane with, but inserted on the
same base as the upper part of the fin ; they are but slightly stronger than the other
rays and prolonged. Body elongate, compressed, covered with small, very thin and
deciduous scales. Head slightly compressed, broad and flat above, depressed in front,
naked (with the exception of the parts between the mandibles, and, perhaps, of the
cheeks). Bones thin, with the muciferous system moderately developed ; only one small
spine above on the operculum ; pr^eoperculum without spine. Eye small. Vertical fins
united, but the narrow caudal projecting beyond the short dorsal and anal rays.
Ventrals each reduced to a filament, whicli consists of two rays firmly bound together in
their whole length; they are inserted behind the humeral symphysis and close together.
Snout broad, rounded, scarcely overlapping the lower jaw. Mouth very wide ; villiform
teeth in the jaws, on the vomer and palatine bones. Gill-laminae short ; gill-rakers long,
not veiy closely set. Pseudobranchise none.

Mixonus laticejps (PL XXV. fig. B).

Bathynedes latic&ps, Giinth., Ann. and Mag. Nat. Hist., vol. ii., 1878, p. 20.

The greatest depth of the body is below the origin of the dorsal fin, and one-third of
the length of the trunk (including head). The distance of the vent from the snout is
two-thii'ds of its distance from the extremity of the spinal column. The length of the
head equals the remainder of the trunk. The crown of the head is remarkably convex,
covered with an extremely thin and transparent skin, which, perhaps, in older examples
is scaly. The interorbital space less convex, and equal in width to the length of the
suout including the eye. Eye small, above the middle of the length of the maxillary,
one-half of the length of the snout, and one-eighth of that of the head. Posterior
nostrils wide, open, in front of the eye.

The distance of the vent from the ventrals exceeds the length of the head. Orioiu
of the dorsal fin above the root of the pectorals, its rays of moderate length, but longer
than those of the anal. Pectoral with a rather narrow base, as long as the head without
snout ; its rays are feeble, seventeen in number, of which the three or four lower ones
are a little stouter, detached, and prolonged. The ventral filaments do not reach as far
backwards as the pectoral.

REPORT ON THE DEEP-SEA FISHES. 109

Gill-rakers ten, much longer than the laminae. Whitish, with the abdomen and o-iU-
apparatus black.

Habitat. — One specimen, 5^ inches long, was obtained in Mid- Atlantic (Station 104),
at the enormous depth of 2500 fathoms.

Bathyonus.

Bathynectes sp., Giintli., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 20.
Bathyonus sp., Goode and Bean, Proo. U.S. Nat. Mus., vol. viii., 1886, p. 603.

Body compressed, with long tapering tail, covered with deciduous thin scales of

moderate size. Bones of the head very soft and cavernous, the upper opercular spine

' very feeble, ridge-like ; no other armature on the head. Head scaly, except the snout,

I which is obtusely rounded ofl", with the jaws equal or nearly equal in front. Mouth very

I wide ; bands of villiform teeth in the jaws, on the vomer and palatine bones. Barbel

( none. Eyes small. The anterior nostril about midway between the posterior and the

extremity of the snout. Vertical fins confluent ; ventrals close together, reduced to a
pair of simple filaments, and inserted below the rounded angle of the prseoperculum.

Gills four, with short gill-laminas, but with long stiff gill-rakers on the first branchial
arch. Pseudobranchise none. Branchiostegals eight. Pyloric appendages none.

Bathyo7ius compressus (PI. XXII. fig. A).

Bathynectes compressus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 20.
D. 116. A. 92. P. 23. V. 1.

->

The greatest depth of the body is above the end of the gill-cover and about one-half
of the length of the trunk, the vent being twice as distant from the extremity of the
tail as from the snout; consequently, the tail is but moderately attenuated. Head
compressed like the body, and about two-thirds of the length of the trunk; the
superficial bones form large muciferous cavities which, when full, must give to the head
a much more evenly rounded appearance thau in the preserved state, when the supporting
bony ridges project more or less from under the skin. The snout is slightly swollen, but
the jaws are nearly even in front, the wide mouth slightly ascending forwards. The
maxillary has the form usual in these Gadoid fishes, is dilated behind, and extends far
behind the eye.

The eye is very small, one half of the length of the snout, and about one-eleventh of
that of the head ; it is placed high up on the side, and does not possess an orbital
fold of the integument. The interorbital space rather convex and equal in width to
three diameters of the eye.

110 THE VOYAGE OF H.M.S. CHALLENGER.

All the teeth are very small and short, densely set, and form villiform bands. The
broadest is that of the maxillary bone, and it is quite uncovered on the sides, no labial
folds being developed. The palatine band is broader than the mandibulary, and the
vomerine band A-shaped, each arm being bent with the convexity inwards.

Gill-opening and cavity very wide and of an intense black. The gill-rakers are
much longer than the laminse, fifteen in number on the anterior arch, besides some
rudimentary ones above.

The dorsal fin commences above the upper end of the gill-opening, with short rays
partly hidden in the skin ; the rays become longer in the middle of the fin, but remain
of moderate length, and the anal rays are still shorter. The pectoral has a rather narrow
base, is quite free, and composed of feeble rays ; its length is only half that of the head.
Ventral rays very feeble, reaching somewhat beyond the root of the pectoral.

Only very few of the thin, cycloid scales have been preserved ; they are of moderate
size, there being about sixteen in a transverse series running from the vent to the dorsal
fin. The lateral line, if it was developed, can no longer be traced.

Blackish, with the fins, head, and abdomen black.

Specimens of this very fine and truly bathybial fish were obtained at great depths on
the south-east of New Guinea, ofi^ the Philippine Islands, and in the Mid-Atlantic.

Habitat.- — Seventy-five miles east-south-east of Raine Island, Station 184; depth,
1400 fathoms. Two specimens, 17 and 4^ inches long.

Philippine Islands, Station 205 ; depth, 1050 fathoms. One specimen, 5^ inches
long.

Mid- Atlantic, Station 107 ; depth, 1500 fathoms. One specimen, 5^ inches long.

The young specimens are extremely similar to the old, but have a larger eye, which is
only one-eighth of the length of the head. The specimen from Station 205 (Philippine
Islands) has longer ventral filaments, extending nearly to the vent.

Bathyonus taenia (PI. XXIII. fig. A).

D. 138. A. 115. P. 30. V. 1.

The greatest depth of the body is below the origin of the dorsal fin, and about one-
third of the length of the trunk, the vent being not quite thrice as distant from the
extremity of the tad as from the snout. Therefore the whole fish, and especially the tail,
is much attenuated. Head not compressed, low and long, forming four-sevenths of the
length of the trunk. Structure of the bones of the head as in Bathyonus compressus.
Snout rather swollen and broad, the upper jaw but slightly overlapping the lower.
Maxillary extending far behind the eye, which is very small, one-third of the length of
the snout, about one-fourteenth of that of the head, and one-fourth of the width of the

REPORT ON THE DEEP-SEA FISHES. Ill

iuterorbital space. All the teeth are very small and short, densely set, forming narrow

villiform bands ; vomerine band open, A-shaped. Gill-cavity deep black ; gill-rakers

long and slender, sixteen in number, with some rudimentary ones in front and behind.

I The dorsal fin commences above the upper end of the gill-opening, with short rays

' partly hidden in the skin ; the rays become longer on the anterior third of the tail,

I but remain of moderate length, and the anal rays are stUl shorter. The pectoral

has a broad base, is quite free, and composed of rather feeble rays ; its length is equal

to that of the postorbital portion of the head. Ventral rays very feeble, reaching nearly

to the middle of the pectoral.

The scales must have been extremely thin, and rather small ; there were probably
about twenty in a transverse series running from the vent to the dorsal fin. The lateral
line cannot be made out.
\ Light-coloured (possibly pink in life), with the head and abdomen black.

^- — Habitat. — Only one specimen of this eminently bathybial fish was obtained in Mid-
Atlantic (Station 104), at a depth of 2500 fathoms. Its total length is 10 inches.

Bathyonus catena.

Bathyonus catena, Goode and Bean, Proo. U.S. Nat. Mus., vol. viii., 1886, p. 603.

Tail much attenuated; height of the body two-thirds of the length of the head.
Head not much compressed ; width of the iuterorbital space equal to the diameter of
the eye, about equal to the length of the snout, and one-fifth of that of the head. GiU-
rakers long, about fifteen in numljer. Origin of the dorsal fin slightly behind the root
of the pectoral ; pectoral four-fifths as long as the head. The distance of the vent from
the root of the ventral rather more than the length of the head. Brownish-yellow, head
and abdomen blackish.

Habitat. — This species evidently belongs to the same genus as Bathyonus compressiis
and Bathyonus taenia ; it is known from two specimens, 8 and 9 inches long, obtained
by the U.S. Fish Commission in lat. 28° N., long. 87° 42' W.; at a depth of 1467
fathoms.

Porogadus.

Porogadus, Goode and Bean, Proo. U.S. Nat. Mus., vol. viii., 1886, p. 602.
Body compressed, with long, tapering taU, covered with very thin, small, deciduous
scales. Bones of the head soft, with the muciferous channels moderately developed.
Operculum with a spine above; some of the other cranial bones project as spines.
Snout rather depressed, with the jaws equal in front. Mouth very xvdde ; bands of
ivlliform teeth in the jaws, on the vomer and palatine bones. Barbel none. Eyes

112 THE VOYAGE OF H.M.S. CHALLENGER.

small. The anterior nostril niucli smaller than the posterior and about midway between
the posterior and the extremity of the snout. Vertical fins confluent ; ventrals close
together, close to the humeral symphysis, each composed of two subequal filaments.

Gills four, with very short laminae, but with long stiff' gill-rakers on the first
branchial arch. Pseudobranchi^e rudimentary.

Porogadus gracilis (PI. XVI. fig. B).

Bathynedes gracilis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 21.

Head and body low, rather compressed ; tail produced into a long filament. The
greatest depth of the body is on a level with the root of the pectoral, and is two-sevenths
of the length of the trunk. The length of the head is nearly one-half of the same
length. Eye of moderate size, its diameter five and a half times in the length of the
head, and two-thirds of that of the snout and of the width of the interorbital space,
which is somewhat convex. The posterior nostrils are very wide and separated from
the eye by a small spinous projection of bone. The muciferous channel of the infra-
orbital ring shows in its course five or six wide sinuses, that of the prseoperculum four
or five. The integument of the head being very thin, underlying projections of the
bone appear in preserved specimens as small prominent spines above the posterior
portion of the eye ; on the shoulder there is a single short spine. Prseoperculum
without spines. Mouth very wide, extending far behind the eye, the extremity of the
maxillary much dilated. The teeth form narrow bands, that of the vomer is A-shaped,
with the two arms straight. The dorsal fin commences above the root of the pectoral,
its rays being of moderate length, but longer than those of the anal. Pectoral with
feeble rays, tapering, as long as the head exclusive of the snout. Each ventral is
composed of a bifid filament, the longer part of which extends backwards as far as the
pectoral.

Scales very thin, cycloid, small, with the exception of some (about seven), which
form a series running from the upper end of the gill-opening towards the dorsal fin ;
these are about three times the size of the others. About twenty-four may be counted
in a transverse series running from the vent to the dorsal fin.

Outer branchial arch with sixteen long and slender gill-rakers, the longest of which
are about five times as long as the laminae. Of pseudobranchise only two minute lobules
can be distinguished.

Colour light brownish, head and abdomen black.

Habitat. — A single specimen, 9 inches long, was obtained at Station 184, south of
New Guinea, at a depth of 1400 fathoms.

EEPORT ON THE DEEP-SEA FISHES. 113

Porogadus miles.

Porogadus miles, Goode and Bean, Proc. U.S. Nat. Mus., vol. viii., 1886, p. 602.

Tail much attenuated, the length of the head being contained six and a half times in
the total. Eye contained five and three-quarter times in the length of the head, and
rather less than the width of the interorbital space. The maxillarj- extends far behind
the eye. Head with numerous spines on the interorbital space, two pairs on the shoulders,
one at the angle of the operculum, and a double series on the angle of the praaoper-
culum ; and with numerous mucous pores. Behind each posterior nostril a strong spine,
projecting outwards and backwards. The distance between the root of the ventrals and
the vent nearly equals the length of the head. Origin of the dorsal somewhat behind
the vertical from the base of the pectoral. Blackish-brown.

Habitat. — A single specimen, 153 mm. long, was obtained by the U.S. Fish Com-
mission in lat. 38° 27' N., long. 73° 0' W., at a depth of 1168 fathoms.

Porogadus rostratus, n. sp. (PI. XXIV. fig. B).

B. 8. D. 120. A. 95 (?). P. 21. V. 2.

This species diff'ers strikingly from the two preceding by its much shorter form, and
by the peculiar shape of its snout.

The body is moderately compressed, the head depressed, especially in its rostral
portion. The greatest depth of the former is about the middle of the abdomen, and two-
fifths of the length of the trunk, of which the head forms a little more than one-half.
The trunk (including the head) is fully two-thirds of the length of the tail, which rapidly
tapers to a fine point.

Head as broad as high, its width being equal to the length of the postorbital portion ;
snout depressed, with its central portion slightly produced, overlapping the lower jaw.
Mouth wide, extending to the hind margin of the orbit. Eye small, immediately below
the upper profile, one-ninth of the length of the head, one-third of that of the snout, and
two-fifths of the width of the flat interorbital space. The nostrils are somewhat remote
from each other, the posterior being wide, round and open. The folds of the mucous
membrane of the nasal cavity are arranged in two rows, forming together a longitudmal
pad with a linear base.

The bones of the head are rather thin, and the superficial shaped into large sinuses.
Spines are developed on the operculum, which is armed above with a short horizontal
spine ; on the pr^operculum, the margin of which is irregularly crcnulatod ; behind the
supraciliary edge, where a sliort spine points backwards ; and finally, behind the posterior
nostril, which is separated from the orbit by a very short spinous projection. The
muciferous channels are very wide, that of the frontal bone opens in front by a wdde

(ZOOL. CHALL. EXP. — PART LVII.— 188G.)

114 THE VOYAGE OF H.M.S. CHALLENGER.

aperture on each side of the rostral projection ; a longitudinal ridge runs along the
infraorbital ring. Each mandibulary canal opens in front immediately behind the
symphysis by a slit in the skin.

Teeth in villiform bands in the jaws, on the vomer and palatine bones, the vomerine
band being A-shaped and much narrower than the palatine band.

The dorsal fin begins above the posterior third of the pectoral, and is composed of
densely set, fine and rather short rays, which, however, are a little longer than those of
the anal fin.^ Pectoral with a narrow base and feeble rays, not quite half as long as the
head. The ventral filaments are still shorter, very feeble, close together, and inserted
opposite to the rounded angle of the prseoperculum.

The scales are cycloid, not deciduous, and rather irregularly arranged. Traces of a
lateral line can be distinguished at various parts of the body, but they are not continuous.
About thirty scales can be counted in a transverse series running from the vent to the
dorsal fin. The upper and lateral parts of the head, and also the rami of the mandible,
are covered with small thin scales.

The gill-laminse are short, shorter than the stifi" and widely-set gill-rakers, which are
eight or nine in number. Of pseudobranchise only two or three small lobes can be
distinguished. Pyloric appendages none.

Uniform black.

Habitat.- — Only one specimen, in an excellent state of preservation, \\\ inches long,
was obtained North of Celebes (Station 198), at a depth of 2150 fathoms.

Nematonus, n. gen.

Bathyonus sp., Goode and Bean.

This genus differs from Porogadus merely by the absence of spines on the head.'

Nematonus pectoralis.

Bathyonus pecioralis, Goode and Bean, Proc. U.S. Nat. Mus., vol. viii., 1886, p. 604.

B. 8. D. 93. A. 73. P. 17. V. 2.

Tail moderately elongate. Eye rather small, one-seventh of the length of the head,
and slightly less than that of the snout. Distance of the root of the ventrals from the
vent rather more than the length of the head. The penultimate ray of the pectoral pro-
longed, nearly twice as long as the head. About twenty-three scales in a transverse series
running from the vent to the dorsal fin. Eighteen long gill-rakers on the first arch.
Brownish-yellow, head and abdomen blackish.

' In consequence of some injury during life, a small portion of the anal fin is lost.

2 The operculum prohably is armed with a small spine behind, as in the majority of the fishes of this group.

EEPORT ON THE DEEP-SEA FISHES. 115

Habitat. — Two specimens were obtained by the U.S. Fish Commission ; one 8 J inches
long in lat. 28° N., long. 87° 43' W., at 1430 fathoms; the other, 2| inches long, ofl'
Dominica in 330 fathoms.

Diplacanthopoma, n. gen.

Body compressed, elongate, covered with small and thin scales ; lateral line very
indistinct ; head rather depressed, naked, with thin bones and wide muciferous channels.
Eye of moderate size. Nostrils far apart, the posterior widely open, in front of the eye,
and the anterior at the extremity of the snout. Operculum with two spines, one
pointing backwards, the other situated behind the angle of the prseoperculum and
pointing downwards ; prseoperculum unarmed. Snout not swollen, broad, depressed,
the upper jaw slightly overlapping the lower ; barbels none. Mouth of moderate
width ; bauds of villiform teeth in the jaws, on the vomer and the palatine bones. Tail
attenuated ; vertical fins confluent ; ventrals close together, reduced to a pair of simple
filaments and inserted somewhat behind the isthmus below the middle of the operculum.
Gills four, with lanceolate, widely-set gill-rakers, and well-developed laminae. Pseudo-
branchiae none.

Diplacanthopoma brachysoma, n. sp. (PI. XXIII. fig. C).

The greatest depth of the body is below the origin of the dorsal fin, and contained
twice and one-third in the distance of the extremity of the snout from the vent. The
head is about as deep as broad, its length being equal to the distance of the vent from
the root of the ventral fins, and more than one-half of the length of the body exclusive
of the tail. The vent is nearer to the snout than to the root of the caudal. Eye of
moderate size, without orbital fold, as long as the snout, one-fifth of the length of the
head and equal to the width of the flat iuterorbital space. Mouth of moderate width,
the maxillary extending somewhat behind the eye and being slightly dilated behind.
All the teeth are in narrow villiform bands, that of the vomer being open and A-shai)ed.
The superficial bones of the head are thin, and those of the infraorbital ring and of the
mandible dilated for the reception of the wide mucous canals. Of the opercular spines
the horizontal is remarkably long, much longer than the lower vertical one.

The vertical fins are completely united, and, owing to the great attenuation of the
tail, no caudal portion can be distinguished. The rays are very thin, closely set, and of
moderate length. Origin of the dorsal fin immediately behind the root of the pectoral,
and that of the anal immediately behind the vent. Pectoral fins rather narrow, inserted on
a short, broad, and partly free pedicle ; they are longer than the postorbital portion of the
head ; ventrals half as long as the distance of their root from the vent.

116 THE VOYAGE OF H.M.S. CHALLENGER.

The scales are rather small, thin, cycloid, and rather deciduous ; if a lateral line
is present, it is confined to the trunk.

Upper parts of a uniform light brownish colour ; the lower parts and the fins
colourless.

Habitat. — Off" Pernambuco, coast of Brazil, Station 122 ; depth, 350 fathoms. One
specimen, 4|^ inches long.

Acanthonus.
Acanthonus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 22.

Head excessively large and thick, armed in front and on the opercles with strong
spines ; trunk very short, the vent being below the pectoral ; tail thin, strongly com-
pressed, tapering, with the caudal distinct. Eye small. Mouth very wide, with the
teeth in villiform bands in the jaws, on the vomer and palatine bones, and along the
hyoid. Barbel none. Ventrals each reduced to a bifid filament, placed close together
on the humeral symphysis. Gill-membranes not united. The giU-laminae are remark-
ably short ; the gill-rakers long, lanceolate, stiff". Scales extremely small. Bones of the
head soft, the superficial supporting large cavities.

A true deep-sea form of extraordinary shape, but otherwise not diff"ering from the
typical Ophidiidse.

The gills are four in number, a long slit being behind the fourth. The long gill-
rakers (PL XXIV. figs, a, a') are confined to the middle piece of the first branchial
arch, about twenty in number, of which the hindmost are nearly -^ inch long. The gill-
laminge are very short, but it is possible that they were longer during life, and have
shrunk by the action of the spirit; they are slender, like tentacles, free at their extremity.
The air-bladder is lodged in a spacious cavity below the abdominal portion of the vertebral
column ; its membranes are thin where they are attached to the walls of the abdominal
cavity, only that portion which separates the organ from the intestines being of a
firmer texture. Its posterior portion does not extend to between the muscles of the tail,
and is subdivided into several smaller cells by trabecule.

The stomach is elongate, externally distinguished from the intestine by a covering
of black-coloured peritoneum ; the peritoneal lamina, which covers the intestine,
being colourless. It is, in the specimen examined, contracted, and does not appear to
have been capable of that extraordinary degree of distension which is observed in other
deep-sea forms. The intestine makes one and a half convolutions and is short. Liver
small. Urinary bladder large ; kidneys limited to the posterior part of the abdominal
cavity. Testicles oblong.

The specimen dissected had two gland-like masses attached to the posterior edge of

REPORT ON THE DEEP-SEA FISHES. 117

the liver and the lower portion of the intestine. They were enveloped in a dense
membrane with polished, pearly surface. The contents consisted of more or less
confluent cysts filled with a cheesy matter, probably the remains of perished parasitic

worms.

Acanthonus armatus (PI. XXIV. fig. A).

Acanthomas armatus, Giinth., Ann. and Mag. Nat. Hist, 1878, voL ii. p. 22.
B. 9. D. + C.-l- A. 100 + 3 + 88. C. 8. P. 18. V. 2.

The head of this remarkable fish appears of an extraordinary thickness, compared
with the thin and compressed trunk and tail ; it is" very broad across the frontal regions
and not much longer than high ; the small eye being much nearer to the end of the
snout than to the gill-opening. The snout would be truncated in front, but for its upper
projecting portion which terminates in two short acute spines. The large mouth is
slightly oblique, the maxiUary extending backwards beyond the middle of the length of
the head. The jaws are equal in front. Two sharp ridges run along each ramus of
the mandible, to receive between them a wide muciferous channel.

The angle of the preeoperculum is armed with four spines, three of which are placed
on the outer edge of the bone ; the upper is the longest and dagger-shaped, pointing
backwards, the middle is shorter, broader, and points, like the third and smallest, down-
wards. The fourth is placed anteriorly to the first, arising from the anterior lamella of
the bone, short and directed outwards. The longest spine of the head is part of the
operculum, which otherwise is a ver}^ thin and narrow bone ; this spine is nearly two-
fifths the length of the head, styliform, deeply grooved above and below, and pomts
backwards.

The nostrils are rather close together, and on the side of the snout; a large
mucous aperture in front of them, below the rostral spines.

The entire head and body were covered with minute scales, thin and deciduous, and
mostly lost in the specimens. The lateral line is represented by a series of small,
distant black pores, running along the proximal ends of the interneural spines.

The length of the body and tail is not quite thrice that of the head; the vent
placed immediately behind the root of the pectoral ; its distance from the root of the
ventrals is less than the length of the head.

The dorsal fin begins nearly above the root of the pectoral, but some rudimentary
rays are more advanced and hidden under the skin. The rays are moderately loug,
longer than those of the anal fin, and gradually decrease in length as they approach the
end of the tail ; in one of the specimens the small caudal is distinctly free from the
other fins. Pectoral fin with broad base, rounded edge and eighteen thin rays, the longest

1

inch.

1 line.

3

j>

4 „

4
3

118 THE VOYAGE OF H.M.S. CHALLENGER.

of which are two-fifths as long as the head. The ventral filaments are about half the
length of their distance from the vent.

The entire fish is either black or of a reddish-white colour, with the exception of the
jaws and abdomen, which, like the buccal and branchial cavities, are of a deep black, as is
so often the case in deep-sea fishes.

Distance of the snout from the eye.

Distance of the snout from the gill-opening,

Distance of the snout from the vent,

Total length, .....

Habitat. — Philippine Islands, Station 205 ; depth, 1050 fathoms. One specimen,
13 inches long.

North of New Guinea, Station 218; depth, 1070 fathoms. One specimen, 11|
inches long.

Of the figures on PL XXIV. figure a represents the outer and figure a' the inner
aspect of the first branchial arch.

Typhlonus.
Typhlonus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 21.

Head large, compressed, with most of the bones in a cartilaginous condition ; the
superficial bones with enormous muciferous cavities, not armed. Snout a thick pro-
tuberance, projecting far beyond the mouth, which is rather small and inferior. Trunk
very short, the vent being below the pectoral ; tail excessively compressed, deep, tapering,
without separate caudal. Eye not visible externally, reduced to a minute rudiment
hidden below the skin. Bands of villiform teeth in the jaws, on the vomer and palatine
bones. Barbel none. Veutrals reduced to simple filaments, placed close together on
the humeral symphysis. Gill-openings very wide, the gill-membranes being but
slightly united in front. Gills four ; gill-laminse very short, gijl-rakers of moderate
length. Scales thin, deciduous, small. /'

A true deep-sea form.

After removal of the extremely thin skin from the side of the head, a partly cartila-
ginous partly membranaceous layer is laid bare, which is formed by the greatly expanded
dermal bones and the walls of the mucous cavities. The place of the orbital cavity is
covered by this layer, underneath which a minute black globular body (smaller than
a pin's head) represents the rudiment of an eye. The opercular bones are almost
membranaceous, the sub- and interoperculum supported by fibrous rays. Vertebrae
thin, but ossified. The abdominal cavity does not extend into the tail. Liver small.
Stomach apparently not much distensible, covered by a lamina of the black peritoneum.

REPORT ON THE DEEP-SEA FISHES. 119

Intestiae with two and a half convolutious. Air-bladder a simple, thin-walled sac.
Kidneys large, extending far forwards. Ovaries enclosed in a membranous sac.

Mr. Murray* observes : — " This Ophidiid had a large, rounded, fleshy head ; no trace
of an eye could be seen other than a small dark spot a considerable distance underneath
the skin. The fins were black, but the body of the fish was white ; with the exception
of one or two, all the scales had been rubbed off", and with them apparently a thin
black skin, so that probably the fish when first caught by the trawl was of a uniform
black colour ; the mouth and gill-chambers were black."

Typhlonus nasus (PI. XXV. fig. A).

Typhlonus nasus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 21.

The head of this most remarkable form is somewhat compressed, deep, as thick in the
rostral as in the opercular portion ; its length is rather more than one-fourth of the total.
Protuberances, formed by projecting portions of the cranium, occupy the upper and
lateral surfaces of the head ; and more especially one in front, and another on each side
of the snout are very conspicuous.

The cavities between them are large, muciferous ; during life, when these cavities
are full, the whole head must be enveloped in mucus.^ No apertures leading into them
are visible anywhere. The snout is thick, projecting far beyond the mouth, which is
rather small, horse-shoe-shaped and quite at the lower side of the head. A thin skin,
covered with very small scales, envelops the whole head. The nostrils are close
together situated on the lateral prominences of the snout.

The depth of the body is not quite equal to the length of the head. The scales appear
to have been irregularly arranged, and no lateral line is visible. The dorsal fin commences
above the root of the pectoral, and is composed of numerous feeble and rather short rays;
it passes without interruption into the caudal and anal. The distance of the vent from
the root of the ventral is only half the length of the head.

Pectoral rounded, composed of twenty-six feeble rays, reaching beyond the vent ;
ventral filaments beyond the extremity of the pectoral.

Light brownish, with black fins.

iya&itoi.— North-east of Australia, Station 181; depth, 2440 fathoms. One
specimen, 10 inches long.

North of Celebes, Station 198 ; depth, 2150 fathoms. One specimen, 10 inches long.

' Narr. Chall. Exp., vol. i. p. 520. , • v •,

2 The external configuration of the head during life is evidently very different from the appearance ^vlnch it

presents in specimens preserved in strong spirits. After the specimen had been submerged in diluted alcohol tor the

purposes of dissection, the mucus still remaining in the cavities swelled into a gelatinous mass, distending the

membranes, so that the contours of the head appeared rounded.

120 THE VOYAGE OF H.M.S. CHALLENGER.

Aphyonus.

/ Aphyonus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 22.

Head, body and tapering tail strongly compressed, enveloped in a thin, scaleless, loose
skin. Vent far behind the pectoral in nearly the middle of the total length. Snout
swollen, projecting beyond the mouth, which is wide. No teeth in the upper jaw ; small
conical teeth in the lower, pluriserial in front and uni.serial on the side. Vomer with
a few rudimentary teeth ; palatine teeth none. Nostrils close together, small. No
externally visible eye. Barbel none. Ventrals reduced to simple filaments, placed close
together, and near to the humeral symphysis. Gill-membranes not united. Four
branchial arches, the posterior without gill-laminse ; the anterior with very short gill-
rakers and with rather short gill-laminae. Head covered with a system of wide muciferous
channels and sinuses, the dermal bones being almost membranaceous, whilst the others
are in a semicartilaginous condition. Notochord persistent, but with a superficial
indication of the vertebral segments (as in some Leptocephaline fonns).

Although this fish resembles Tt/jMonus in so many points that one might be induced
to regard it as an early stage of development of that fish, no such direct relation can
obtain between them. The single individual obtained by the expedition has the ovaries
fully developed, filling one-half of the abdominal cavity, the ova being apparently mature
and ready for exclusion. It is, therefore, a persistent and independent type, the lowest of
all Anacanths, so far as is known at present, which has remained stationary at an early
stage of its development. The abdominal organs do not show any peculiarity, and are
very similar to those of TyiMoyius.

Aphyonus gelatinosus (PI. XXVI. fig. A).

Aphyomw gelaiinosus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 22.

The head, in the preserved specimen, is compressed, rather deep, and enveloped in
loose skin ; especially on the upper side of its anterior half the skin forms a large loose
bag, which, during life, is probably filled and distended with mucus.

The snout overlaps the wide mouth, the maxillary extending backwards nearly to
the middle of the length of the head. A rudiment of the eye, in the shape of a minute
black globular body, is hidden below the skin in a recess of the infraorbital mucous sinus,
as in Typhlonus. Seen from above, the head appears convex, rather broad ; its length
is less than its distance from the vent and one-fourth of the total.

The body is strongly compressed and deep, its depth at the beginning of the dorsal
fin being one-third of the distance of the vent from the snout ; also the tail is deep and
short, shorter than the rest of the body. The skin covering the muscular parts is not
loose, very thin, transparent, so that the myocommas can be clearly seen through it.

REPORT ON THE DEEP-SEA FISHES. 121

The integument of the abdomen is loose, and forms a double fold in the median line,
which, however, extends only to about the middle of the length of the abdomen. The
vent and genital openings project as thick papUlse.

The vertical fin is continuous, and supported throughout by extremely numerous,
densely set, fine cartilaginous rays ; it commences immediately behind the vertical from
the root of the pectoral, and is continued round the tail to the vent. Pectoral with a
broad base, and thirty-three fine rays, rounded, more than half as long as the head.
Ventral filaments stoutish, with a narrow fringe of skin, as long as the pectorals.

Transparent, colourless, like a Leptocephalus.

Habitat. — Between north-east Australia and New Guinea, Station 184; depth, 1400
fathoms. One specimen, 5^ inches long.

Mr. Murray ^ mentions that three specimens were obtained of this fish. However, on
closer inspection, one only of these three specimens proved to be an Aphyonus, the two
others belonging to difi'erent genera.

Rhodichthys.
^~~~~~^ Rhodichthys, Collett, Norsk. Nordh. Exped. Fisk., p. 153.

Head thick, body and tad strongly compressed, the latter tapering behind, enveloped
in a thin, transparent, scaleless skin. Vent immediately behind the humeral symphysis.
Snout swollen, overlapping the wide mouth. A few series of weak teeth in the jaws,
none on the vomer or palate. Eye of moderate size. Ventrals reduced to two filaments,
each bifid, and inserted on the hyoid. Vertical fins continuous, but with caudal rays
difierentiated. Gill-openings very wide. Pyloric appendages ten.

Rhodichthys regina.

Rhodichthys regina, Collett, Norsk. NordL Exped. Fisk., p. 154, pi. v.

Ventral filaments long. Uniform bright red during life.

Habitat— A. single example, nearly 12 inches long, was obtained by the Norwegian
expedition in the sea between Bear Island, Jan Mayen, and Finmark, from a depth of
1280 fathoms.

» Narr. Chall. Exp., vol. i. p. 521.

(ZOOL. CHALL. EXP. — PAET LVII. — 1886.) L^l ^6

122 THE VOYAGE OF H.M.S. CHALLENGER.

Family M a c r u R i T)M.
Macrurus.

Head generally with large muciferous ca"vities, most developed in the suborbital ring,
and continued into the praeoperculum and into the snout, which frequently projects more
or less beyond the mouth. The mouth may be inferior or subterminal and lateral, is
armed with small teeth, and the palate is toothless. A barbel at the symphysis of the
lower jaw. Scales sometimes typically ctenoid, sometimes cycloid ; no scaleless fossa
on the side of the nape. The second dorsal is always less developed than the anal, and
its anterior rays, or all of them, are more or less rudimentary. Gill-membranes slightly
united in front. Four gills with well-developed gill-laminae; no pseud obranchise. A
broad fold of the membrane of the gill-cavity stretches across to the terminal portions of
the first branchial arch, and renders the slit between that arch and the wall of the gill-
cavity much narrower than the slits between the arches. Gill-rakers of the first
branchial arch broad, low, cartilaginous bodies, generally armed with curved spines.

Before the Challenger Expedition the known species of Macrurus were few in
number, and they were but sparingly represented in museums. Thus, when I gave a
general account of them in the year 1862, I knew from autopsy five only, and I believed
I recognised in them the types of three genera, which I distinguished by the form of the
snout and position of the mouth, by the size of the scales and modifications of the
dentition.

The dredge of the Challenger secured more than one hundred and forty examples,
referable to thirty species, and proved that this type of fishes is not only one of the
most widely spread in the depths of all oceans, but also extremely abundant with regard
to species and individuals. These materials afforded the further evidence that the
characters on which I had relied for the generic groups of Macrurus, Coryphsenoides,
and Malacocephalus, did not possess the taxonomic value assigned to them, with the
exception of the modifications of the dentition, which, however, were capable of more
precise definition.

With regard to the form of the snout and position of the mouth, there exists
every gradation, from the most specialised types, such as Macrurus japonicus and
Macrurus parallelus, to Macrurus longifilis, which may be regarded as representing the
original type whence the others were derived. Its head is compressed, well projjortioned,
formed by firm bones, the superficial of which enclose a muciferous system not more
enlarged than we find it in many surface fishes ; its snout is not more tumid or project-
ing than in the majority of surface Gadoids, and the wide mouth terminal and lateral. As
the muciferous cavities increase in width, the bones are expanded into thin lamella3 and lose

EEPORT ON THE DEEP-SEA FISHES. 123

in firmness, those of the infraorbital ring cover more or less the side of the head, extend
backwards to the angle of the prseoperculum, and push the latter backwards. The snout
becomes the receptacle of large or even enormously enlarged cavities, supported by thin
osseous ridges, and projects more or less beyond the mouth, which is forced downwards
to the lower surface of the head, like that of a shark. Thus, great as the dissimilarity
is between the extreme forms of the snout in the species of Macncrus, there is no
fundamental difference in structure ; they merely represent different degrees of the same
line of modification.

With regard to the scales, there is also every gradation from the small-scaled
Malacocephali to the large-scaled Macrunis longibarbis. In very young specimens of
all species the scales formed at first are always thin, without any armature, in fact
cycloid. Spines appear only after some time, generally in the median line of the scale,
singly and not in series ; scales with fully developed armature are generally not found in
specimens under 8 inches in length. In some species which normally possess strongly
spiniferous scales, individuals may occur (especially such whose skin is wanting in
pigment), in which the spines are much more feeble and scarcely visible. And finally,
there are species in which the cycloid structure of the scales remains normally persistent.
Thus, neither the size nor the structure of the scales can be safely used as a generic
character.

The serrature or smoothness of the dorsal spine is a constant character,' the serrature
but rarely becoming obsolete with age, and never disappearing altogether so far as my
observations go. In very young specimens the barbs are comparatively further apart
and less numerous than in older ones, in which the barbs of more recent growth are more
adpressed to the body of the spine, more closely arranged, and more numerous at the
base than towards the top.

The dentition is an infallible aid in the discrimination of the species, and therefore is
used here as the main character in their arrangement.

1 have generically separated from the Macruri those forms which do not possess
the characteristic attachment of the first branchial arch to the outer wall of the gill-
cavity ; but with regard to the host of the other species, I do not think that they should
be more widely separated than in the form of subgeneric groups ; there is no doubt that
many more species will come to light, which may lead to a different mode of ai-ranging
the species.

It is singular that, although the Macruridse are represented in the deep-sea by such a
great number of species and individuals, no young specimens in the Krohnius-stage'' were
obtained by the expedition.

> This character has also been iisetl by Lutken in a synopsis of genera and species, Vid. Meddel. not. Form.
Kj()benhavn, 1872, p. 4.

2 Gf. Emery, N. Acmd. d. Line. Rom., voL iii., 1879.

124 THE VOYAGE OF H.M.S. CHALLENGER.

Systematic Arrangement of the Subgenera of Macrurus}

I. Teeth in villiform bands above and below, that of the lower jaw always broadest
near the symphysis, and sometimes tapering into a series on the side of the jaw.

A. Scales distinctly imbricate, without enlarged dorsal scales.

1. Scales spinigerous : —

a. Mouth entirely at the lower side of the head, a
longitudinal ridge dividing the infraorbital
region into a vertical and subhorizontal por-
tion. Dorsal spine smooth, . . . ', Ccelorhynchus.

h. Mouth inferior ; infraorbital ridge more or less

distinct. Dorsal spine serrated, . . '•• Macrurus.

c. Mouth wide and lateral. Dorsal spine serrated, Coryphsenoides.

d. Mouth wide and lateral. Dorsal spine smooth, Mystaconurus.

2. Scales smooth, . . . . . - Lionurus.

B. Scales indistinct, the whole skin covered with villosities, Trachonurus.

C. A series of enlarged scales along the base of the dorsal and

anal fins, . . . . . . ' Cetonurus.

II. Intermaxillary heterodont, with an outer series of strong widely-
set teeth, and an inner villiform band ; mandibulary teeth uniserial.

A. Dorsal spine serrated, . . . ' . . ' Chalinurus.

B. Dorsal spine smooth, ..... Optonurus.

III. Intermaxilliary teeth uni- or biserial; mandibulary teeth uni-
serial.

A. Dorsal spine smooth, . . . . , Malacocephalus.

B. Dorsal spine serrated, ..... Nematonurus.

' Owing to insufficient description no further notice can be taken here of the following species : —

1. Macrurus macrolepidohis, Kaup {Archivf. Nalurgesch, 1858, p. 91). Scales with fourteen to fifteen keels;
twelve scales only from the anus upwards to the back.

2. Macrurus acrolepis, Bean {Proc. U.S. Nat. Mus., vol. vi. p. 362). Washington Territory.

3. Macrurus carrihxus, Goode and Bean {Proc. U.S. Nat. Mus., 1886, p. 594), from the northern part of the
Gulf of Mexico, depth 210 fathoms (belongs to the section Coslorhynchus).

4. Malacocephalus occidentalis, Goode and Bean {Proc. U.S. Nat. Mus., 1886, p. 597), from depths of 132 and
164 fathoms, in the western and central Atlantic (would seem to belong to the section Nematonurus).

5. Macrurus occa, Goode and Bean {loc. cit., p. 595), from 335 fathoms in the western central Atlantic. The
authors consider this a near relation to Macrurus trachyrhynchus, but as they do not mention either
the large dorsal scales, or the temporal fossa, or the structures of the gills, it is quite as likely that it is
one of the long-snouted species of true Macruri.

REPORT ON THE DEEP-SEA FISHES. 125

Subgenus Ccelorhynchus.

Ccelorhynchus, Giorna.

Macrurus parallelus (PI. XXIX. fig. A).

Macrurus paralleliis, Giinth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 439.
D. 10. A. 90. V. 7. P. 16. C. pyl. 12.

Snout much produced, subtriliedral, pointed, nearly twice as long as the large eye.
Scales with five or even seven spiny ridges, which are nearly parallel to one another, and
of which the middle one is the strongest, terminating in a more or less strongly projecting
spine. Head covered all over with irregular, spiny, tubercle-like scales, of which those
along the infraorbital crest and along two lines on each side of the crown of the head
are the strongest. There are five scales in a transverse series between the first dorsal
and lateral line. Outer ventral ray produced into a short filament. Cavity of the mouth
and of the gills and abdomen black.

Habitat. — Off New Zealand; Station 169; depth, 700 fathoms. One specimen, 18^
inches long.

Off the Kermadec Islands, Station 170a; depth, 630 fathoms. Three specimens, 23,
12 and 7 inches long.

Off the Kermadec Islands, Station 171; depth, 600 fathoms. Two specimens, 2^
inches long.

Hyalonema-ground, off luosima, Japan, Station 232; depth, 345 fathoms. Eight
specimens, 12 to 17 inches long.

South of Japan, Station 235 ; depth, 565 fathoms. One specimen, 5^ inches long.

The length of the head is but little less than the distance between the barbel and
vent, the snout being much produced, subtrihedral, depressed, acutely pointed in front,
and nearly twice as long as the large eye. The horizontal diameter of the eye is much
longer than its vertical, and equal to the width of the flat interorbital space in a specimen
23 inches long. The posterior nostril is twice as wide as the anterior ; the flap which
separates them is of a black colour. Angle of the prseoperculum produced backwards into
a short lobe ; eye nearer to the point of the operculum than to the end of the snout, two-
ninths of the length of the head. Pectoral rather small, equal in length to the post-
orbital portion of the head, much longer than the ventrals. The first dorsal ray feeble,
as long as the pectoral, inserted at a very short distance behind the vertical from the
root of the pectoral. The relative length of the abdominal cavity is liable to change with
the growth of the fish ; in a specimen 23 inches long, the distance between vent and
isthmus is two-thirds of the length of the head, whilst it is only one-half in an example of
half that length.

126 THE VOYAGE OF H.M.S. CHALLENGER.

The scales are somewhat differently sculptured on the different parts of the body of
the fish, in individuals of different ages, and in specimens from different localities. In a
specimen from the Kermadec Islands, 23 inches long, a scale (fig. a), taken from the
middle of the fish above the lateral line, has from five to seven nearly parallel ridges, of
which the middle one is the highest, ending behind in a strong spine. The other ridges
are more or less faint, with small spines either at the end or in the middle. In the scales on
the back (fig. a'), as well as on the abdominal region, the median spine projects strongly and
is preceded by two or three smaller ones, which cover each other in an imbricate fashion.
In the scales of the lateral line the median ridge is, as it were, longitudinally divided
by the muciferous channel, forming above and below the line a series of imbricate spines,
Generally no other ridges being visible on these scales. On the head the scales are more
or less modified into scutes, with serrated ridges, which form more or less regular stellate
figures on each scute, rendering the whole surface of the head very rough ; the largest
scutes are those occupying the raised bony ridges which are found in every species of
this genus. The course of the muciferous channels on the snout and other parts of the
head can be easily traced by series of very small and short black tubules, by which the
mucous secretion is discharged, and which are particularly numerous on the lower part of
the snout.

In a specimen from the Kermadec Islands, which is only 12 inches long, all the spinous
projections are comparatively weaker and the parallel ridges on the scales less distinct.

In a New Zealand specimen, 18|- inches long, the dermal ossifications on the
head are considerably smaller, so much so that they do not always touch each
other; also on the body the spines project less, but the parallel arrangement of the
ridges is much more conspicuous. On the other hand, in Japanese specimens the arma-
ture is much more developed, and there is not the same great difference in the size of
the median and lateral spines.

In a young specimen 5^ inches long from Japan (fig. A') the snout has already
the characteristic form and is nearly twice as long as the eye, the body is scaled, and on
some of the scales (fig. a") minute spines are arranged in two or three series, but not
close enough to form continuous ridges. No scutes are visible on the head except
along the osseous ridges found in nearly all the species of this genus.

Very young specimens (fig. A"), 2^ inches long, are partially covered with extremely
delicate scales (fig. a'"), those on the back being armed with a stronger median
and sometimes an additional pair of weaker lateral spines. The ridges on the head are
simply serrated and the snout is comparatively shorter, the eye being only two-thirds of
its length.

Figures A of PI. XXIX. represent the entire view of a specimen from the Kermadec
Islands, and the lower view of its head, of nearly two-thirds of the natural size ; A', side
view of the head of a young Japanese specimen (5^ inches long); A", a very young

EEPORT ON THE DEEP-SEA FISHES. 127

specimen from the Kermadec Islands, a and a' are scales of specimen A, somewhat
magnified, the former from the side, the latter from the back; a", highly magnified scale
of specimen A'; a'", highly magnified scale of specimen A".

Macnirus japonicus (PI. XXIX. fig. C).

Maerums japonicus, Schleg., Faun. Japon. Poiss., p. 256, pi. cxii. fig. 2.
D. 11 I 70. C. 6. A. 74. P. 18. V. 7.

Snout much produced, subtrihedral, pointed, nearly twice as long as the large eye,
which is two-ninths of the length of the head. Scales with from three to five strong
radiating keels, each keel terminating in a spine. Head covered all over wdth similar or
spiny tubercle-like scales, of which those along the infraorbital ridge and along a line on
each side of the crown of the head are the strongest. There are five scales in a transverse
series between the first dorsal and lateral line. Outer ventral ray produced into a short
filament. Length of abdomen equal to that of the head (without snout) in adult
specimens (20 inches long).

Habitat. — South of Japan, Hyalonema-groujid ; off" Inosima, Station 232 ; depth,
345 fathoms. One specimen, 21^ inches long.

This species is very closely allied to Macriirus parallelus, but the keels on the scales
diverge or radiate, whilst they are subparallel in the latter species. I see that the two
heads which the British Museum ^ received under the name of the present species belong
to a very distinct fish, evidently a new species, which may be described when more
complete materials are available.

Macrurus australis.

Lepidoleprus australis, Richards, Proc. Zool. Soc. Lond., 1839, p. 100.
Macrurus australis, Giinth., Fish., vol. iv. p. 391.

D. 12-13. A. 87-96. V. 7. P. 16.

Snout moderately produced, pointed, rather longer than the eye in old specimens, and
rather shorter in younger ones. Each scale with from twelve to eighteen parallel keels,
and with the margin more or less distinctly crenulated. Head covered entii-ely witli
rather irregularly shaped scales, of which those along the infraorbital crest and along
two indistinct lines on each side of the crown of the head are particularly rough. There
are four scales in a transverse series between the first dorsal fin and the lateral line.
Dorsal spine smooth. Abdomen, that is, distance of the vent from the isthmus, equal to
the distance of the end of the operculum from the anterior nostril in adult specimens.

1 Cat. Fish., vol. iv. p. 395.

Head.

Eye.

Snout.

42 lines

12 lines

11 lines

54 „

16 „

20 „

128 THE VOYAGE OF H.M.S. CHALLENGEE,

The typical specimen, which is nearly 17 inches long (head 3^ inches) came from
Port Arthur. But the species appears also on the New Zealand coast, whence I have
received specimens 21 inches long, the head measuring 4-| inches. These specimens
offered evidence of the change of the form of the snout which the species of this genu^
undergo with age, the snout being comparatively longer in old specimens than in young
ones, as may be seen from the following measurements : —

a. Port Artliur,
h. Wellington,

Several very young specimens, 4 to 4g inches long, were obtained by the Challenger
at Station 166, in 275 fathoms. In these the snout is comparatively still shorter, and
scales are developed only on the anterior part of the body. There is a fontaneUe-like
depression between the ventral fins, but it does not seem to persist throughout life in this
species, as in Macrurus coelorhynchus. Also in an example 5^ inches long, from Cape
Campbell, New Zealand, the ventral fontanelle is still present, but the whole body is
clothed with hard and well-developed scales, which, however, show a structure different
from that of the scale of the adiUt fish. Each scale is provided with five radiating keels,
prominent, and projecting beyond the margin of the scale. Each keel, being in fact a
series of imbricated spines, is serrated in its whole length.

Macrurus coelorhynchus.

Lepidoleprus cceJorhijnchus, Eisso, Ichth. Nice, p. 200, pi. vii. fig. 22; Eur. m^rid., iii., p. 244.
Macrourus coelorhynchus, Bonap., Faun. Ital. Pesc. (pi., Macrourus mysticetus).

„ „ Costa, Faun. Nap., pi. xxxix.

,, „ Canestrini, Arch. Zool., ii. p. 374.

„ ,, Johns., Ann. and Mag. Nat. Hist., 1862, vol. x. p. 169.

,, „ Vinciguerra, Ann. Mus. Genov., vol. xiv., 1879, p. 619 ; vol. xviii.

1882, p. 565.
Macrurus atlanticus, Lowe, Proc. Zool. Soc. Lond., 1839, p. 88.

„ „ Giinth., Fish., vol. iv. p. 392.

D. 10. A. 75-86. P. 20. V. 7.

Snout moderately produced, angular in front, a little shorter than or equal to the eye,
the diameter of which is one-third of the length of the head. Scales of moderate size,
covered with minute spines, giving a granular appearance to their surface. There are
five or six scales in a transverse series, between the first dorsal fin and the lateral line.
Dorsal spine smooth. Abdomen, that is, distance of the vent from the isthmus, equal to
the length of the head without snout in specimens about 12 inches long. Outer ventral
ray produced into a short filament.

REPORT ON THE DEEP-SEA FISHES. 129

All the six specimens which I have examined, from 11 to 13 inches long, have the
abdominal region and the ventral fins of a black colour. In all specimens there is
a scaleless elliptical depression between the ventral fins, covered by a thin, smooth
membrane only.

This species has hitherto been found in the Mediterranean and near Madeira. Collett.i
believes that a. specimen, 260 mm. long, which he obtained from the stomach of a Codfish
near Bergen, belongs to -this species.

Macrurus carminatus (PL L. fig. B).

Macrurus carminatus, Goode, Proo! U.S. Nat. Mus., vol. iii., 1881, pp. 346, 475 ; Bull ilus.
Comp. ZooL, vol X., No. 5, p. 196.

D. 10. P. 18. V. 7.

This fish is very closely allied to Macrurus coelorhynchus, having a similar naked
space between the ventral fins, but the spines of the scales are conspicuously longer.
Snout long, sharp, depressed, triangular, a little longer than the diameter of the eye,
which is contained three and a quarter times in the length of the head, and more than
the width of the interorbital space. Teeth small, conical, somewhat recurved, in villiform
bands. Barbel very short. Scales densely covered with long depressed spines ; five
transverse rows above and twelve below the lateral line, counting from the vent obliquel}'
backwards. Anterior dorsal spine smooth ; pectoral fin more than half as long as the
head. Outer ventral ray produced into a short filament. The distance between the two
dorsal fins equals half the length of the head. Coloration uniform.

Habitat. — Specimens (9^ inches long) were obtained by the U.S. Fish Commission on
the east coast of the United States, in depths varying from 115 to 464 fathoms. Our
specimen, which is of the same length, was obtained in the vicinity of the Bahama Islands.

Macrurus fasciatus (PL XXVIII. fig. A).

Macrurus fasciatus, Gunth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 24.

D. 12. A. 62. P. 15. V. 7.

Snout not much produced, shorter than the eye, which is very large, two-fifths of
the length of the head, its vertical diameter being considerably more than the width
of the interorbital space. Scales with from eight to ten subparallel keels. Upper and
lateral portions of the head covered with small, rough scales, lower naked. There are
four scales in a transverse series between the first dorsal spine and lateral line ; distance
between the two dorsal fins equal to the length of the base of the first. Anterior

1 Norges Fisk., p. 129.

(zoOL. CIIALL. EXP. — PART LVII.— 1886.) Lil i- i

130 THE VOYAGE OF H.M.S. CHALLENGER.

dorsal spine smooth. Outer ventral ray produced into a filament. Distance between
vent and isthmus shorter than the head, without snout. Barbel small. Whitish, with
broad, irregular, blackish bands across the back.

Habitat. — East coast of the southern extremity of South America, Station 311 ;
depth, 245 fathoms. Five specimens, 7 to 10 inches long (in bad condition).

East coast of the southern extremity of South America, Stations 309, 309a ; depth,
40 to 140 fathoms Two specimens, 6| and 10 inches long.

East coast of the southern extremity of South America, Station 305a ; depth, 125
fathoms. One specimen, 1^ inches long.

This species is closely allied to Macrurus australis, but differs in having a narrower
forehead, larger eye, and fewer keels on the scales. In the smaller and younger specimens
the keels are fewer in number (five to six), and have a more divergent direction than in
the largest example.

Subgenus Macrurus.

Macrurus, proposed by Bloch for Macrurus fahrieii.

Macrurus fabricii (Sundevall).

Macrurus fahrieii, Collett, ISTorges Fisk., p. 128.

„ ,, Lilljeb., Sverig. och Norg. Fisk., p. 242.

D. 12 I 124.' A. 148.' P. 18-19. V. 8.

Snout short, subtrihedral, pointed in front, much shorter than the large eye, which is
one-third or two-fifths of the length of the head in adult specimens. Scales with a
prominent serrated ridge and more or less distinct lateral keels ; there are six longi-
tudinal series of scales between the first dorsal fin and the lateral line. The first dorsal
spine indistinctly denticulated towards the point. Vent situated behind the origin of the
second dorsal fin.

This species is not uncommon on the northern coasts of Scandinavia, and on the
coasts of Greenland and North America southward to Massachusetts.

Of four specimens which I have before me, no two agree in certain not unimportant
points, and it is possible that more than one species may be distinguished by other
observers. They are all nearly of the same size, viz., about 24 inches long, one being
from Finmarken, two from the coasts of Greenland, and the fourth from the New
England coasts. One of the Greenland sj)ecimens has a conspicuously smaller eye,
which is not quite one-third of the length of the head, or less than the distance between
the orbit and the angle of the prseoperculum. This specimen has also the interorbital

' These numbers are subject to great variation.

REPORT ON THE DEEP-SEA FISHES. 131

space of greater width and less concave than other specimens, the width being two-thu-ds
of the diameter of the eye; the posterior limb of the prseopereulum is much more oblique,
whilst in the other specimens it is almost vertical. The scales of the Greenland
specimens are much more smooth, and in one of them only a few of the scales show traces
of the lateral keels. The scales are roughest in our specimens from Finmarken, and they
scarcely possess a scale which does not show lateral keels or spines. The length of the
pectoral fin is subject to great variation; in the Finmarken specimen it is short, contained
twice and one-fourth in the length of the head; in the New England specimen long, and
contained once and four-fifths in the length of the head, the Greenland specimens being
intermediate in this respect.

Macrurus rudis (PL XXVII. ).

Coryphmnoides rudis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 24.
D. 10 I 94. A. 96. P. 19. V. 10.

Snout obtusely conical, projecting beyond the mouth, which extends backwards to
beyond tlie middle of the eye. The outer series contains stronger teeth in both jaws.
Barbel about as long as the eye. The 2:)rofile of the nape ascends very slightly towards
the dorsal fin. Scales equally rough over the whole of their surface, the spinelets being
subequal in size, densely packed, and not arranged in series. There are eight scales in a
transverse series between the first dorsal and the lateral line. Anterior margin of the
second dorsal spine armed with barbs placed at some distance from each other. The
second dorsal fin commences at a distance behind the first scarcely inferior to the length
of the base of the first. The outer ventral ray produced into a long filament.

Habitat. — Pacific, north of the Kermadec Islands, Station 171; depth, 600 fathoms.
Three specimens, 3 inches, 11 inches, and 33 inches long.

Pacific, north of the Kermadec Islands, Station 170a; depth, 630 fathoms. Three
specimens, 6 to 7 inches and 12 inches long.

Pacific, north of the Kermadec Islands, Station 170; depth, 520 fathoms. Two
specimens, 3^ inches long.

As in other fishes, so in Macrurus, the eye is comparatively larger in young than in
adult individuals. In our large examj^le the head is 175 mm., the eye 25 mm., the snout
43 mm., and the width of the interorbital space 50 mm. These dimensions being in the
smaller respectively 50, 16, 15, and 13 mm.

Also the serratui-e of the dorsal spine changes with age, the biU'bs being widely set
and few in number (seven) in very young specimens 6 inches long (fig. c), much more
numerous (twenty) in older examples 11 inches long (fig. h), and becoming rather
obsolete in adult ones.

132 THE VOYAGE OF H.M.S. CHALLENGER.

But the most extraorcliuary change takes place in the position of the vent. In young-
specimens (of 12 inches and less) the vent is placed between the ventrals (fig. a),
immediately behind their roots at some distance from the origin of the anal, and the
distance between vent and isthmus is only about half the length of the head. In the
adult, in which the abdominal organs are fully developed, the external extent of the
abdomen is also enlarged, the vent being moved backwards behind the ventrals
immediately in front of the anal, and the distance between vent and isthmus has been
much increased, being equal to the length of the head.

Macrurus nasutus (PI. XXX. fig. B).

Coryphamoides nasutus, Giintli., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 440.
Allied to Macrurus rudis.

D. 12 I 95. A. 110. B. 20. V. 10.

Snout obtusely conical, with a rather sharp upper edge, and with a more or less pro-
jecting knob in the middle. The snout projects beyond the mouth, the cleft of which
does not reach to below the middle of the eye. The teeth of the outer series are scarcely
stronger than the remainder. Barbel very small. The width of the interorbital space is
not quite equal to the vertical diameter of the eye, which, in a specimen 14 inches long,
is nearly one -fourth of the length of the head, and equal to that of the snout. The
structure of the scales is almost identical with that in Macrurus rudis. They are
equally rough over the whole of their surface, the spinelets being subequal in size, densely
packed, and not arranged in series. The majority of these spinelets are strengthened by
a strong longitudinal keel (fig. h). There are seven or eight scales in a transverse series
between the first dorsal and the lateral line. Second dorsal spine somewhat produced,
armed along its anterior edge with barbs pointing upwards and rather closely set. The
second dorsal fin commences at a considerable distance behind the first, the distance being
nearly equal to the length of the head. The outer ventral ray produced into a filament,
shorter than the fin.

Habitat. — South of Yeddo, Station 235; depth, 565 fathoms. Five specimens,
14^ and 14 inches long.

Hyalonema-ground, ofi" Inosima, Japan, Station 232 ; depth, 345 fathoms. Six
specimens, about 12 and 13 inches long.

The number of dorsal and anal rays must always be subject to considerable variation,
because the end of the tail is not equally produced in all individuals. In several specimens
the tail has been mutilated at an early stage of growth, and in such cases the truncated
stump is surrounded by a rayed fin, very much of the same appearance as the caudal fin
of the ordinary Teleostean type.

EEPORT ON THE DEEP-SEA FISHES. 133

This species is also closely allied to Macrurus serrulatus, but lias the dorsal spine
diflferently serrated. Its eye is comparatively smaller, and the postorbital portion of the
head, as well as the snout longer. Mouth small.

Macrurus serrulatus (PI. XXX. fig. A).

Coryphxnoides serrtilatus, Giinth., Ann. and Mag. Nat. Hist, 1878, vol. ii. p. 26.

D. 10. A. 108. P. 19. V. 7.

The projecting part of the snout is short, with an obtuse upper edge, and with a
rough tubercle in the middle. The cleft of the mouth extends to below the middle of
the eye, which is comparatively large. The teeth of the outer series are visibly stronger
than the remainder. Barbel about as long as the eye. The interorbital space is flat, its
width rather less than the diameter of the eye, which, in a specimen 16 inches long, is a
little less than one-third of the length of the head, and more than that of the snout.
The scales are equally rough over the whole of their surface, the spinelets being subequal
in size, densely packed, closely adpressed to the scale, and not arranged in series. There
are seven scales in a transverse series between the first dorsal and the lateral line.
Second dorsal spine finely and closely serrated in front. The second dorsal fin
commences at a considerable distance from the first, the distance being equal to the
length of the head. The outer ventral ray produced into a filament.

Habitat. — North-east of New Zealand, Station 169 ; depth, 700 fathoms. Three
specimens, 13, 15, and 16 inches long.

One of these specimens had had the tail mutilated at an early stage of growth ; and
the fin-rays which surround the mutilated portion are longer than those on the ventral
edge of the extremity of the tail, simulating a caudal fin, as shown in fig. a.

Macrurus sclerorhynchus (PI. XXXII. fig. A).

Macrurus sclerorhynohus, Valenc. in Webb and Berth., Des Canar., p. 80, pi. xiv. fig. 1.
„ „ Vinciguerra, Ann. Mus. Genov., val. xiv., 1879, p. 622, Tab. iL

D. 11. A. 95. P. 17. V. 7.

Snout conically projecting beyond the mouth, with sharp and smooth canthus
rostralis ; a rough protuberance in front, aud one on each side of the canthus. Mouth
rather small, situated at the lower side of the snout ; infraorbital ridge sharp, prominent
in its whole length. The cleft of the mouth does not extend to below the centre of
the eye. Teeth in vHliform bands, in both jaws ; those of the outer series of the
upper jaw scarcely stronger than the others. Barbel short and slender. Interorbital

134 THE VOYAGE OF H.M.S. CHALLENGER.

space flat, its width being equal to the vertical diameter of the eye. The horizontal
diameter of the eye equals the length of the snout, and is two-sevenths of that of
the head.

The scales are covered with very small spinelets, which are arranged in about nine
series, the middle series being sometimes more prominent than the others ; only the
terminal spinelet of the central series projects sometimes beyond the margin of the scale.
There are six scales in a transverse series between the first dorsal spine and the lateral
line. Second dorsal spine somewhat produced, armed in front with rather closely set
barbs. The distance between the two dorsal fins equals the length of the head, the snout
not included. The outer ventral ray produced into a filament. Brown.

Habitat. — Atlantic, between the Canary Islands and south of Portugal ; Mediter-
ranean.

Ninety miles south-east of Cape St. Vincent, Station V.; depth, 1090 fathoms.
One specimen, 11 inches long.

The determination of this specimen is subject to some doubt ; it does not show so
strong a central keel on any of the scales as is represented by Valenciennes, though some
scales have the central series of spinelets decidedly enlarged. This specimen is also
closely allied to those which I have separated under the name of Macrurus sequalis.
But the interorbital space is wider, and the spinelets of the scales are much more
numerous than in the latter species*

Macrurus sequalis (PL XXXII. fig. C).

? Macrounis serratus, Lowe, Proc. Zool. Soc. Lond., 1843, p. 91.
Coryphsenoides xqualis, Gunth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 25.

AUied to Macrw^s rudis.

1 D. 12. A. 90-118. P. 17. V. 9.

Snout conically projecting beyond the mouth, with rather obtuse and rough upper
edge ; the cleft of the mouth extends nearly to below the centre of the eye. The teeth
of the outer series are visibly stronger than the remainder. Barbel slender, but not so
long as the eye. The upper profile rises rather suddenly towards the anterior dorsal
spine. The interorbital space is flat, its width being considerably less than the diameter
of the eye, which conspicuously exceeds the length of the snout, and is one-third or
rather more than one-third of the length of the head. The scales are equally rough
over the whole of their surface, the spinelets being subequal in size, densely packed, but
arranged in from eight to twelve series, the middle series not being more prominent
than the others (as is the case in Macrurus sclera rhynchus). The entii-e margin of the

"<:

REPORT ON THE DEEP-SEA FISHES. 135

scale is spinous. There are eight scales in a transverse series between the first dorsal
and the lateral line. Second dorsal spine somewhat produced, armed along its anterior
edge with barbs pointing upwards and rather closely set. The second dorsal fin
commences at a distance from the first which is less than the length of the head. The
outer ventral ray not, or but slightly, produced. Lower part of the head and antero-
superior portion of the first dorsal black.

Habitat. — South of Portugal, Station IV.; depth, 600 fathoms. Two specimens,

8 to 9 inches long.

This species is very closely allied to Macrurus mdis, from which it difi"ers, however,
in several minor points, such as the number of ventral rays, the size of the dorsal
profile, &c. The interorbital space is conspicuously narrower, when specimens of the
two species of nearly the same size are compared. In a specimen of Macrurus sequalis,

9 inches long, the greatest diameter of the eye is 13 mm. long, and the interorbital
space only 9 mm. wide.

The type of Macrourus serratus of Lowe is lost, and the short diagnosis he has given
of it does not enable us to decide which of the closely allied species — Macrurus scler-
orhynchus, Macrurus aequalis, Macrurus hairdii, Macrurus goodii — he had before him.
As he distinctly says that the ventral fin is produced into a filament, I cannot refer the
specimens mentioned above to his species, as I should otherwise have been inclined to do.

One of the specimens has been mentioned and rudely figured by Sii' Wyville
Thomson/ under the name of Coryph^noides serratus.^

Macrurus hairdii (PI. XXXII. fig. B).

Macrurus bairdii, Goode and Bean, Amer. .Journ. Sci. and Arts, vol. xiv., 1877, p. 471 ; and
vol. xvii., 1879, p. 40; Proc. U.S. Nat. Mus., vol. iiL, 18S1, p. 475;
Bull. Mus. Comp. Zool., vol x., No. 5, 1883, p. 195.

D. 12. A. 117. P. 18. V. 7.

This species is very closely allied to Macrwnis wqualis, but distinguished from it by
a distinctly longer snout, which is nearly equal to the diameter of the eye, and by the
smaller number of ventral rays (seven).

Habitat. — Specimens were obtained by the American surveying vessels, at various
localities off the coast of New England, in 160 to 740 fathoms.

» The Atlantic, vol. i. p. 118, fig. 3.

' Although the matter is of no importance, I must apologise to M. Vinciguerra for having inadvertently mism-
formed him in a letter as regards my determination of that specimen (see Ann. Mus. Genov., vol. xviii. p. 566). I con-
founded the specimen with the one which I have referred to Macrurus sclerorhynchus.

136 THE VOYAGE OF H.M.S. CHALLENGER.

Macrurus goodii.

Macrums asper, Goods and Bean, Bull. Mus. Comp. Zool., vol. x., No. 5, 1883, p. 196.
D. 10-11. P. 20. V. 10.

Allied to Macrurus hairdii} Width of the interorbital space a little greater than
the horizontal diameter of the orbit, contained four and a quarter times in the length of
the head, and equal to that of the snout. Cleft of the mouth extending to the hind
margin of the orbit. Teeth "in the jaws" (upper jaw?) in a very narrow, villiform
band, the outer series slightly larger ; those in the lower jaw apparently in a single
series (?). Barbel shorter than the eye. Scales with the spines arranged in about seven
rows, the middle not being keel-like, although the median marginal spine projects most
strongly. Seven series of scales above the lateral line. Vent at a distance from the
ventral considerably greater than the length of that fin. Outer ventral ray slightly
produced. Reddish-brown.

Habitat. — Several specimens, the longest 12 inches long, were obtained by the U.S.
steamer "Blake," between lat. 40° and 41° N., long. 65° and 68° W., at depths of 304
and 1242 fathoms.

Macrurus liolotrachys (PI. XXVIII. fig. B).

Macrunts hdotrachys, Giinth., Ann. and Mag. Nat. Hisfc., 1878, vol. ii. p. 24.
D. 11. A. 115. P. 21. V. 9.

Snout moderately produced, as long as the eye, which is large, one-third of the
length of the head, its vertical diameter being considerably more than the width of the
interorbital space. Anterior edge of the snout with three i-ough prominences, one in the
middle, and one on each side. Mouth inferior, lower side of the head naked. Each
scale with a median series of spinelets, and with two or more isolated spinelets besides ;
the median are the strongest, forming with their fellows continuous longitudinal lines on
the body. Upper and lateral portions of the head covered with irregular, rough scales,
lower naked. There are five scales in a transverse series between the first dorsal spine
and lateral line. Teeth of the lower jaw in a very narrow band. Distance between
the two dorsal fins scarcely equal to the length of the base of the first. Second dorsal
sprue with small barbs anteriorly ; outer ventral ray produced into a short filament.
Distance of the vent from the isthmus equal to the length of the head, without snout.
Barbel very small. No bands or spots.

Habitat.— East of the mouth of the Rio de la Plata, Station 320; depth, 600
fathoms. One specimen, 9 inches long.

1 Hence probably with a barbed dorsal spine, no mention being made by the authors of this character.

REPORT ON THE DEEP-SEA FISHES. 137

Macrurus asper (PL XXXVI. fig. A).

Coryphxnoides asper, Giinth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 440.
D. 11. A. 89. P. 25. V. 10-11.

Snout short, slightly projecting beyond the mouth. Eye of moderate size, not much
shorter than the snout, and two-ninths of the length of the head ; interorbital space flat,
wider than the eye. Mouth extending to below the middle of the eye. Teeth of the
outer series in the upper jaw stronger than the remainder. Barbel rather shorter than
the eye. Prseoperculum with the hind margin not excised, and subvertical, and with
both limbs densely scaly. Scales with five radiating series of long and slender spines.
There are six scales in a transverse series between the first dorsal fin and the lateral line.
Second dorsal spine considerably produced, armed in front with rather distant barbs.
The second dorsal fin commences at a short distance behind the first. The outer ventral
ray produced into a filament. Black.

Habitat.— Bo-ath of Japan, Station 237; depth, 1875 fathoms. One specimen,
13 inches long.

Macrurus carinatus (PL XXXIII. fig. A).

Coryphxnoides carinatus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 28.
D. 12. P. 21. V. 8.

Snout obtusely conical, projecting beyond the mouth, the cleft of which reaches nearly
to below the middle of the eye. Teeth of the upper jaw in a band, those of the lower
likewise crowded in front and in a single series on the sides. Barbel well developed, but
much shorter than the eye. Interorbital space flat, much narrower than the large eye,
the diameter of which equals the length of the snout, and is only a little less than one-
third of that of the head. The distance between vent and isthmus is nearly equal to the
length of the head.

The scales are of moderate size and provided with a very strong median keel,
terminating in a projecting spine, and with several short and low ridges which converge
towards the median keel, or run nearly paraUel to it. There are five scales in a
transverse series between the first dorsal and the lateral line. Prteopcrculum with the
hind margin undulated, and with the limbs scaly. The second dorsal spine is armed
with rather small and somewhat closely set barbs. The distance between the two dorsal
fins equals the length of the base of the first. Pectoral fin rather more than half as long
as the head. Outer ventral ray produced into a very short filament. Brown.

iIa&{to«.-Near Prince Edward Island, Station 145a; depth, 310 fathoms. One
specimen, 11^ inches long.

(ZOOL. CHALL, ESP. — PAKT LVII. 1886.)

138 THE VOYAGE OF H.M.S. CHALLENGER.

Subgenus Coryphsenoides.
Coryphxnoides, name proposed by Gunner for Goryphse.noides rupestris.

Macrurus rupestris.

Coryphsenoides rupestris, Gunner, Trondhj. Selsk. Skrift., vol. iii. p. 50, tab. iii. fig. L

„ „ Goode and Bean, Bull. Mus. Comp. Zool., vol. x., No. 5, 1883, p. 197.

„ „ Collett, Forliandl. Vidensk. Selsk. Christ., 1880, p. 70; and Nyt

Mag. f. Naturvid., 1884, p. 95; Strom, Norsk. Vidensk. Selsk.
Skrift., 1884, p. 37.
„ „ Lilljeb., Sverig. ocli Norg. Fisk., p. 259.

Macrurus nonoegieus, Nilss., Skand. Faun. Fisk., p. 600.

Macrourus stroma, Keinh., K. dansk. Vidensk. Selsk. Afhandl., vol. vii. p. 129.
„ „ Gaim., Voy. Scand., Poiss., pi. xi.

D. 10. P. 19. V. 7.

Head short, rather compressed ; snout short, obliquely truncated in front ; cleft of
the mouth wide, lateral, extending to beyond the centre of the eye ; intermaxillary not
much shorter than the maxillary. Teeth in villiform bands in both jaws ; barbel very
small. Interorbital space convex, its width being considerably more than the diameter
of the eye, which, in a specimen three feet long, is equal to the length of the snout and
one-fourth of that of the head. The scales are equally rough over the whole of their
surface, all the spinelets being directed backwards ; there are seven or eight scales in a
transverse series between the first dorsal fin and the lateral line. Head entirely covered
with small scales. Anterior dorsal spine armed with numerous small, closely set barbs ;
outer ventral ray produced into a long filament. Distance between the vent and isthmus
two-thirds of the length of the head.

Habitat. — North Atlantic ; a large specimen nearly three feet long, which has served
principally for the above diagnosis, is from Sognefjord, Bergen, and several young
specimens were obtained between Shetland and the Faeroe Islands during the cruise of
the "Porcupine" and " Knight Errant," in from 200 to 500 fathoms. The occurrence of
this species on the east coast of the United States is reported from lat. 41° 32' N.,
long. 65° 55' W.; depth, 524 fathoms.'

Macrurus altipinnis (PI. XXXIX. fig. A).

Coryphxnoides altipinnis, Giinth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 439.
D. 12. P. 21. V. 9.
The snout is rather short, shghtly projecting beyond the mouth, with a prominent
tubercle in the middle. Orbit large, in a specimen 19 inches long, contained four and one-

1 I am unable to place Coryphxnoides carapinus (Goode and Bean, Bull. Mus. Comp. Zool., vol. x.. No. 5, 1883, p.
197), described from the east coast of the United States in connection with the above species, the authors having
omitted to examine the dentition.

REPORT ON THE DEEP-SEA FISHES. 139

third times in the length of the head, and not much shorter than the snout or than the
width of the interorbital space ; eye surrounded by a broad orbital membrane. Mouth
wide, lateral, extending beyond the middle of the eye. Teeth of the outer series in the
upper jaw visibly stronger than the remainder. Barbel shorter than the eye. Prseoper-
culum with the hind margin not excised, and with both limbs densely scnly.

Scales small and comparatively thin, but regularly arranged, with five radiating spiny
ridges, the spines being very small. There are eleven or twelve scales in a transverse
series between the first dorsal fin and the lateral line. Second dorsal spine considerably
produced, armed in front with rather distant barbs, more conspicuous in the upper half
of the spine. The second dorsal fin commences at a short distance behind the first.
The outer ventral ray produced into a filament.

Habitat. — South of Yeddo, Station 237; depth, 1875 fathoms. One specimen, 19
inches long.

Ofi" Japan, Station 235 ; depth, 565 fathoms. Two specimens, 6 inches long.

This is one of the species in which the characteristic physiognomy of the typical
Macruri commences to be lost. The infraorbital ridge is still visible, but is not the
boundary between the side and lower portion of the head ; in fact, the space between
the eye and mouth is vertical, and the cleft of the mouth is lateral, and inferior in front
only. Also the cheeks and prajopcrculum are those of an ordinary Gadoid. The
scales, although they are still ridged, are much less hard than in the typical Macruri.

Subgenus Mystaconurus.

Macrurus longibarhis {PI. XVIII. fig. C).

B. 6. D. 10. P. 11. V. 8.

Snout short, obtuse, with the anterior profile descending in a parabolic curve ; mouth
terminal and lateral, wide, extending beyond the middle of the orbit. Eye very large,
more than one-third of the length of the head, much more than that of the snout, and
twice as wide as the interorbital space. Teeth in both jaws in narrow vUliform bands.
Barbel long, two-thirds as long as the head. Praeoperculum with the hind margin not
excised, without marginal denticulation, and scaleless, like the whole head.

The scales are very large, in two and a half series above the lateral line ; and in
eleven between the vent and the dorsal fin. In the young specimen described they are
cycloid, but with minute spinelets now and then appearing on the surface. The dorsal
spine is smooth. The pectoral fin has a very narrow base and is about two-thii'ds of the
length of the head. The ventral with the outer ray produced into a longish filament,

:x

140 THE VOYAGE OF H.M.S. CHALLENGER.

inserted in the middle of the length of the abdomen, which is slightly longer than the

head.

The specimen is stUl colourless, except on the sides of the head and trunk and along
the middle of the tail, which parts are covered with a silvery pigment. Abdomen and
lower parts of the head black.

Habitat. — Off Matuku, Fiji Islands, Station 173 ; depth, 315 fathoms. One specimen,
5^ inches long.

I Although the specimen is young, it is so unlike any other of the numerous young

Macruri collected by the Challenger, that I cannot but consider it to be a very distinct

! form. It has long passed the larval or Krohnius-sta.ge, and developed specific characters

1 by which it may be recognised, viz., the long barbel, large scales, smooth dorsal spine,

villiform dentition, large eye, parabolic snout, and narrow interorbital space. It

possesses the gill-apparatus characteristic of the true Macruri. The scales of the adult

. may be supposed to be spiny.

Macrurus italicus.

Hymenocephalus italicus, Giglioli (e Issel), Pelagos, p. 228, c. fig. (without description).

D. 12. P. 16. V. 10.

Head deeper than broad, with vertical sides and wide muciferous cavities ; snout
obtuse, short, slightly projecting beyond the mouth, the cleft of which is oblique, anterior
and lateral, and extending to behind the middle of the eye. Teeth in both jaws minute,
of equal size, villiform, in narrow bands. Barbel small. Interorbital space as wide as
the eye, the diameter of which is one-third of the length of the head, and exceeds the
snout in length. Scales extremely thin, deciduous, spiny, of comparatively large size.-"
Preeopercular margin not serrated. Anterior dorsal spine smooth, filamentous; the
distance between the two dorsal fins is but little more than the length of the base of the
former.^ Pectoral fin about half as long as the head. Vent close to the root of the
ventral fins which reach it, and the outer ray of which is produced into a filament. A
triangular scaleless space between the ventral fins, nearly extending to the vent; a small
round naked space, surrounded by spiny scales, in the middle of the prseventral region.
Distance between the vent and isthmus three-fourths of the length of the head. Body

1 No scales whatever are preserved in our specimen on the tail and back, only slight traces of the scale pouches are
visible ; on the sides of the abdomen, which are silvery, no scales had yet been developed, whilst the lower side of the
abdomen, with the exception of the naked spaces described, is covered with spiny scales, the spines being rather long
and irregularly placed as in Macrurus laevis.

^ In the woodcut given by Giglioli about thrice as long, but this figure evidently cannot claim great exactness in
details.

;

REPORT ON THE DEEP-SEA FISHES. 141

_i^ and tail colourless ; sides of the head aud abdomen silvery ; lower parts to the vent
I black.

I I have examined a young specimen from Nice, 5 J inches long; GigUoli's specimen

> seems to have been of about the same size.

There can be no doubt that this is a juvenile form, and if it were not for the dentition
I should not hesitate to refer it to Macrurus lasvis, with which it agrees in several
important characters. However, this relationship, if it does exist, cannot be proved at
present without the evidence of a much more complete series than is at my disposal.

Subgenus Lionurus,
Macrurus Jilicauda (PL XXXIV. fig. B).

Coryphxnoides filicauda, Giinth., Ann. and Mag. Nat. Hist., 1878, voL xx. p. 27.
D. 11. P. 20. V. 9. Ccec. pyl. 7. ,

Snout considerably projecting beyond the mouth, pomted in the middle; it is twice
as long as the eye, which is unusually small, only half as wide as the interorbital space.
Mouth rather wide, extending beyond the centre of the eye. Upper teeth villiform,
in a very narrow band, those of the mandible very small, biserial. Barbel minute.
Prseoperculum with the angle produced backwards, broadly rounded and crenulated on
the margin. The terminal portion of the tail is prolonged into a long filament, more
slender than in any of the other species. Bones of the head soft.

Scales of moderate size, thin, cycloid and deciduous; six or seven in a transverse
series between the first dorsal spine and the lateral line; snout and inferior half of the
infraorbital region naked. The second dorsal spine slender, with the barbs in front very
inconspicuous and sometimes entirely absent. The distance between the two dorsal fins
is less than the length of the head. The outer ventral ray produced into a short filament.
Distance between vent and isthmus less than the length of the head.

Head and trunk whitish, tail brownish, lower part of the head and gill-openicg
black.

Habitat. — Deep-sea on both sides of the South American Continent; Antarctic Ocean.

Station 325; depth, 2650 fathoms. Three specimens, 12, 10, aud 6 inches long.

Station 323; depth, 1900 fathoms. One specimen, 13^ inches long.

Station 299; depth, 2160 fathoms. One specimen, 15 inches long.

Station 158; depth, 1800 fathoms. Two specimens, 13 inches long.

Station 157; depth, 1950 fathoms. Three specimens, 9| inches long.

Station 146; depth, 1375 fathoms. Twelve specimens, 4 to 8 inches long.

142 THE VOYAGE OF H.M.S. CHALLENGER.

This species is clearly one of those in this family which extend to the greatest
depths. The decrease in the size of the eye, the very soft bones, the concomitant want of
firmness in the structure of the scales, and the tail, which tapers into a very fine filament,
indicate its abyssal abode. The scales are nearly all gone in all the specimens obtained.
The species appears to be abundant in individuals, and has, like a true deep-sea fish, a
wide distribution.

Macrurus microlepis.

Coryphxnoides microlepis, Giinth., Ann. and Mag. Nat. Hist., 1878, voL xs. p. 26.

D. 12. V. 10.

Snout short, obliquely truncated, slightly projecting beyond the mouth; eye exceeding
in length that of the snout and the width of the interorbital space. Head much com-
pressed, high. The cleft of the mouth does not quite extend to below the middle of the eye.
Teeth of the outer series visibly stronger than the remainder. Barbel as long as the eye.

Scales small, cycloid. There are thiiteen scales in a transverse series between the
first dorsal fin and the lateral line. Second dorsal spine armed in front with [distant]
barbs; the distance between the two dorsal fins equals the length of the head, without
snout. [Trunk very short.] Outer ventral ray slightly prolonged. [Head and body
dotted with brown.]

Habitat. — Ofi' Matuku, Fiji Islands, Station 173; depth, 315 fathoms. One specimen,
4 inches long.

Although it must appear hazardous to describe a Macruroid from a single young
example, I can hardly hesitate to do so in the present instance, the species being well
characterised by its compressed head, small scales, &c. Some of the characters mentioned
are probably only signs of the immaturity of the individual, and have been enclosed within
brackets.

Subgenus Trachonurus.

Macrurus villosus (PL XXXVI. fig. B).

Coryphsenoides villosus, Giintli., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 441.

D. 10. P. 13. V. 7.

Head compressed, with vertical sides. Snout compressed, very slightly projecting
beyond the mouth, short, not longer than the eye, which is of moderate size, one-fourth
of the length of the head. Interorbital space broader than the eye. Mouth rather
small, lateral, not extending to below the centre of the eye. Infraorbital ridge

REPORT ON THE DEEP-SEA FISHES. 143

obsolete. Teeth in villiform bands ia both jaws. Barbel very small and slender. Angle
of the prseoperculum not produced backwards ; hind margin crescent-shaped. The skin
is densely studded with erect spines, which give to the body and head the appearance of
being covered with short villosities. A series of stronger spines runs along each side of
the base of the second dorsal and anal fins. The second dorsal spine is very slender,
smooth, much shorter than the head; the second dorsal fin veiy low, commencing
immediately behind the first. The ventral fin reaches to the anal ; its outer ray produced
into a very short filament. Space between ventral fins and vent scaleless; the distance
between vent and isthmus less than the length of the head.

Habitat. — South of Yeddo, Station 232; depth, 345 fathoms. One specimen,
8 inches long.

South of the Philippine Islands, Station 214; depth, 500 fathoms. One specimen,
10 inches long.

Subgenus Cetonurus.
Macrurus crassiceps (PI. XXXVII.).

Coryphxnoides crassiceps, Giinth., Aim. and Mag. Nat. Hist., 1878, vol. ii. p. 2.5.1
D. 10. P. 16. V. 10.

Head exceedingly large and thick, especially the anterior portion. Snout with an
anterior naso-rostral canthus, excessively broad and high, short, but longer than the eye,
which is small and not quite one-fifth of the length of the head. Mouth small, inferior,
extending beyond the vertical from the centre of the eye. Teeth villiform, in very
narrow bands in both jaws. Intermaxillaries short. Barbel minute.

Trunk of the body very short, the vent being immediately behind the vertical from
the root of the pectoral. The trunk rapidly passes into the tail, the anterior portion of
which is much contracted in width. The distance between the vent and isthmus equals
the length of the postorbital portion of the head.

The scales are small, studded with long, very fine, curved spinelets, which give the
body the appearance of being covered with short villosities. The entire head densely
covered with villous scales. A series of larger scales runs along each side of the base of
the second dorsal fin. The second dorsal spine is very slender, obscurely denticulated in
front; the second dorsal fin commences at a very short distance behind the first.
Pectoral fin with a narrow base, as long as the postorbital portion of the head. The
outer ventral ray is but slightly produced. Brownish-grey, lower side of the trunk black.

Habitat.— mvih of the Kermadec Islands, Station 170 ; depth, 520 fathoms. One
specimen, 13 inches long.

1 A similar fish, probably identical with the one described above, is noticed under the name of Ma^mrm ghhkeps
(L. Vaill.) in Nature, 1884, No. 560.

144 THE VOYAGE OF H.M.S. CHALLENGER.

North of the Kermadec Islands, Station 171 ; depth, 600 fathoms. One specimen,
14 inches long.

In one of these specimens the tail tapers to a fine point, as is normal in Macruroids,
and in the other the mutilated extremity bears a pseudo-caudal fin composed of several
rays. As in all deep-sea fishes with large muciferous cavities and thin flexible bones,
the form and outlines of the head are liable to shrinking in preserved specimens.

Subsrenus Chalinurus.
Chalinura, Goode and Bean.

Macrurus leptolepis (PI. XX XL).

Corxjphsmmdes leptolepis, Giinth., Aun. and Mag. Nat. Hist., 1877, vol. xx. p. 441.

D. 19. P. 18. V. 9.

Head compressed. The snout is rather long, but its front portion projects but
slightly beyond the mouth, which is almost anterior. The eye is comparatively small,
rather more than one-half the length of the snout, or one-seventh of the length of the
head and three-fifths of the width of the interorbital space. Mouth wide, lateral,
extending to below the hind margin of the eye. The teeth of the outer series of the upper
jaw are widely set and much stronger than those of the villiform band. Maudibulary
teeth in a single series. Barbel as long as the eye. The prseoperculum with the hind
margin excised, and with the angle rounded and produced backwards, naked ; its lower
/ margin is not toothed.

Scales thin and deciduous ; most with five or seven radiating keels, some, especially
on the back, nearly or quite smooth. There are seven scales in a transverse series
between the first dorsal and the lateral line. Those on the gill-cover and in front of
the ventral fins are quite smooth ; the front part of the snout and the lower half of the
infraorbital region scaleless. Second dorsal spine slightly produced, with barbs in front,
which are rather distantly arranged. The second dorsal fin commences at a short
distance behind the first. The outer ventral ray produced into a long filament.
Distance between vent and isthmus equal to the length of the head.

The single specimen is of a dirty whitish colour.

Habitat. — Off the coast of Brazil.

Off Pernambuco, Station 122 ; depth, 350 fathoms. One specimen,^ 18 inches long.

1 1 formerly referred some specimens from the Pacific and Japan to the same species, but I think now that they
can be specifically distinguished on account of the shorter snout.

REPORT ON THE DEEP-SEA FISHES. 145

Macrurus simulus.

Chalinura simida, Goode and Bean, Bull. jVIus. Comp. Zolil., vol. x., No. 5, p. 199.
D. 10. P. 20. V. 9.

Snout long, broad, truncate, not much produced ; mouth subterminal, hiteral, wide.
The diameter of the eye is one-fifth of the length of the head, equal to that of the snout,
and rather less than the width of the interorbital space. Barbel longer than the eye.
Teeth in the upper jaw in a broad villiform band, with the outer series much enlarged;
mandibulary teeth uniserial. Scales cycloid, without armature, but with indications of
radiating striae. Anterior dorsal .spine serrated, the barbs closely adpressed. Outer
ventral ray produced into a long filament.

Habitat. — Specimens were obtained by the U.S. steamer " Blake," between lat. 31°
and 4-1° N., and long. 65° and 78" W., at depths of 333, 647, and 1242 fathoms, the
largest being 18 inches long.

Macrurus fernandezianus, n. sp. (PI. XXXVIII. fig. B).

D. 9. P. 18. V. 10.

Head moderately compressed, but with the sides vertical, the mouth being lateral
and anterior ; also the front margin of the snout is subvertical. Eye rather small, lieing
contained five and a half times in the length of the head, two-thii'ds of that of the snout,
and three-fifths of the width of the interorbital space. Mouth wide, extending nearly to
below the hind margin of the eye ; teeth as in Macrurus lej^tolejns. Prseoperculum with
the hind margin excised, and with the lower margin creuulated. Scales rather thin
and deciduous, but with from three to five series of spines ; also the scales on the head
and in front of the ventral fins are rough ; but the snout, nearly the whole of the infra-
orbital region, and the limbs of the prasoperculum are perfectly scaleless. The distance
between the vent and isthmus equals the length of the head, without snout. Barbs of
the dorsal spine widely set and few in number; outer ventral ray produced. Browmsh;
lower parts of the head, abdomen, buccal and branchial cavities black.

Habitat.— South of Juan Fernandez, Station 300; depth, 1375 fathoms. One
specimen, 1 1 inches long.

Macrurus liocephalus, n. sp. (PI. XXXVIII. fig. A).

D. 11. P. 20. V. 10.

Head compressed, snout moderately long, but slightly projecting beyond the mouth,
which is almost anterior. Eye rather small, two-thirds of the length of the snout and
of the width of the interorbital space, and one-sixth of the length of the head. Mouth

(ZOOL. CHALL. EXP. — PART LVII. — 1886.)

146 THE VOYAGE OF H.M.S. CHALLENGEK.

wide, lateral, extending to below the hind margin of the eye ; teeth as in Macrurus
leptolepis. Pr^operculum with the hind margin excised and with the lower margin
crenulated. Scales thin and deciduous, without conspicuous keels ; there are seven
scales in a transverse series between the first dorsal and the lateral line. The scales on
the sides of the head are quite smooth, but the foremost part of the snout, the lower
portion of the infraorbital region, and the limbs of the prseoperculum are perfectly
scaleless. The distance between the vent and isthmus is less than the length of the
head. Outer ventral ray produced into a long filament. Blackish ; head, abdomen,
buccal and branchial cavities deep black.

Habitat. — Near Yokohama, Japan, Station 237 ; depth, 1875 fathoms. One
specimen, 16 § inches long.

Mid-Pacific, Station 246 ; depth, 2050 fathoms. Two specimens, 7-^ inches long.

Macrurus murrayi (PI. XXXIV. fig. A).

Cm-ijplixnoides murraiji, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 26.
D. 12. P. 20. V. 12.

Snout short, but longer than the eye, which is small, its width being much less
than that of the interorbital space, and one-fifth of the length of the head. Canthus
rostralis obtuse, without median tubercle. The cleft of the mouth is anterior and
lateral, and extends to below the middle of the eye. Teeth of the outer series much
stronger than the posterior villiform band. Mandibulary teeth uniserial. Barbel longer
than the eye.

Scales with from five to seven crenulated radiating keels, some of which project
beyond the rounded posterior margin of the scale. There are seven or eight scales in a
transverse series between the first dorsal fin and the lateral line. Upper and lateral parts
of the head, with the exception of the extremity of the snout, covered with small rough
scales. Anterior dorsal spine slightly prolonged, armed with numerous distant barbs
pointing upwards. The second dorsal fin commences at a considerable distance from the
first, which, however, is rather less than the length of the head. The outer ventral ray
produced into a filament. Distance between the vent and isthmus rather less than the
length of the head.

Brownish ; lower parts of the head, buccal and branchial cavities black.

Habitat. — Ofi" New Zealand, Station 168; depth, 1100 fathoms. Five specimens,
3-^, 7, and 15 inches long.

Four young examples, obtained at the same locality, probably belong to a distinct
species, but they are too immature for identification ; they seem to have the snout more
pointed and longer. Their eye is as small as in the larger specimen.

REPORT ON THE DEEP-SEA FISHES. 147

Subgenus Optonurus.
Macrurus denticulatus.

Macrurus denticulatus, Rich., Voy. Ereb. and Terr., Fisli., p. 53, i^I. xxxii. figs. 1-3.
Corypheenoides 'denticulatus, Giinth., Fish., vol. iv. p. 396.

,, „ Hutton, Fish. ISTew. Zeal., p. 49, No. 80.

D. 13. P. 17. V. 9.

Head compressed, with tlie sides vertical ; snout short, convex, but not overLipping
the mouth, which has the jaws equal, is anterior and lateral, and extends backwards to
below the middle of the eye. The intermaxillary is but little shorter than the
maxillary. Eye very large, more than one-third of the length of the head, longer than
the snout and much wider than the flat interorbital space. Teeth of the upper jaw in a
villiform band, with an outer series of much larger teeth. Lower jaw with a single
series of widely-set teeth on the sides ; near the symphysis the teeth are more crowded,
small, and of ec[ual size. Barbel very short.

Scales of moderate size, densely covered with minute spinelets, which are directed
backwards ; there are six series between the dorsal fin and the lateral line ; snout and
the greater portion of the side of the head scaleless. Anterior dorsal spine smooth;
pectoral fin as long as the head without snout ; outer ventral ray not produced. The
lower margin of the prreoperculum is membranaceous and finely denticulated. Distance
between the vent and isthmus rather more than the length of the head.

Greenish; sides silvery, lower parts of the head and abdomen black.

The slit between the outer branchial arch and the wall of the gill-cavity is much
narrowed by a membrane attached to Ijoth ends of the arch ; it is only about twdce as
wide as the slit behind the fourth arch. The gill-laminse are short, separated from ouo
another. Gill-rakers in a double series ; those of the anterior series of the first arch are
small tubercles, fourteen in number, those of the posterior series longer, and beset with
fine bristles.

The specimens obtained by the Expedition are all of very small size and still
destitute of scales, but the British Museum has received several examples from the
Colonial Museum at Wellington, which are probably adult; they are 15 inches long and
came from Cook's Straits. Hutton says that this fish is thrown up in immense
quantities after heavy gales.

Habitat.— m^ew Zealand, Station IGG ; depth, 275 fathoms. One specimen, 4^
inches long.

The Kermadec Islands, Station 170 ; depth, 520 fathoms. Five specimens, 3 to 4 J
inches long.

148 THE VOYAGE OF H.M.S. CHALLENGER.

Subgenus Malacocephalus.

Malacoeephalus, Gthr.

Macrurus Isevis (PL XXXIX. fig. B).

Macrurus Ixvis, Lowe, Proc. Zool. Soc. Lond., 1843, p. 92.
,^^ Malacocephalus Isevis, Giinth., Fish., vol. iv. p. 397.

j' ^ „ „ Liitken, Vid. Meddel. nat. Foreu. Kj0benhavn, 1872, p. 1.

i D. 13-14. P. 17. V. 9. ^

Head compressed, with vertical sides ; muciferous cavities wide. Snout obtusely
conical, slightly projecting beyond the mouth, the cleft of which is oblique, anterior and
lateral, and extending somewhat behind the middle of the eye. Teeth of the upper jaw
biserial, those of the outer series much stronger than the inner ; mandibulary teeth
uniserial. Barbel shorter than the eye. The interorbital space flat, its width being equal
to, or less than the diameter of the eye, which is large, longer than the snout, and one-
third or two-sevenths of the length of the head. Scales very small, much deeper than
long, covered with short minute bristles. Prseoperculum with the posterior margin
slightly excised above the angle, and with the lower margin not serrated. The entire
head is covered with minute rough scales. Anterior dorsal s^jine smooth. Pectoral fin
about two-thirds of the length of the head. The vent (fig. h) is close to the root of the
veutrals, which reach beyond it ; it lies at the end of an oval scaleless depression, and
there is another triangular scaleless space between the roots of the ventrals. Distance
between the vent and isthmus two-thirds of the length of the head.

Brownish above, sides silvery ; axil, ventrals and the region in front of them black ;
branchial cavity partly black, inside of the mouth white.

Habitat. — This fish has been hitherto found at Madeira and in the Mediterranean ;
and once on the coast of Denmark. The Challenger Expedition obtained a specimen,
17^- inches long, off the coast of Pernambuco (Station 122), in 350 fathoms.

Macrurus macrochir (PI. XXIX. fig. B).

Macrums macrochii; Giinth., Ann. and j\lag. Nat. Hist., 1877, vol. xx. p. 438.

D. 11. P. 18. V. 7.

Head rather compressed, elongate, with vertical sides. Snout produced, tetrahedral,
rather longer than the large eye. Interorbital space nearly flat, its width being somewhat
more than the diameter of the eye, which is contained four and one-third times in the
length of the head. Infraorbital ridge low. Mouth rather wide, lateral, the inter-
maxillary shorter than the maxillary. Barbel very small. Teeth coarsely villiform in a

REPORT ON THE DEEP-SEA FISHES. 149

narrow band in the upper jaw, and in a single series in the lower. The two limbs
of the prseoperculum meet at a somewhat acute angle which is produced backwards.

The second dorsal spine is smoot;h and slender ; and the second dorsal fin commences
at a distance behind the first, which is about one-half of the length of the head. Pectoral
fin remarkably long, extending to the origin of the second dorsal, and equal in length to
the head, the snout not included. The outer ventral ray not produced.

Scales rather thin, with from eight to ten finely crenulated radiating ridges, which do
not project beyond the margin of the scale. There are five scales in a transverse series
l)etween the first dorsal fin and the lateral line. The head is covered with similar radiated
scales, which, however, are irregular as regards size and arrangement ; snout and lower
limb of the prajoperculum scaly.

Browuish-lilack.

Habitat. — Hyalonema-gvound, off Inosima, Station 232 ; depth, 345 fathoms. One
specimen, 27^ inches long.

A very remarkable species, which may be at once recognised by its large head and
long pectoral fin. The figures marked B on PL XXIX. represent the entire fish from
the side, of half the natural size, and the lower side of the snout. The figure of the
scale is magnified four times.

Macrurus sulcattis.

Corij2^1ixnoides sukafus, Goode and Lean, Proc. U.S. Nat. Mus., vol. viii., 1886, p. 596.
D. 10-11. P. 13. V. 7.

Snout short, obtuse, scarcely overhanging the mouth, shorter than the eye, which is
contained thrice and two-thirds in the length of the head, and equal to the width of
the interorbital space. The maxillary reaches to below the middle of the orbit. Dorsal
spine smooth. Vent about midway between the root of the ventrals and tlie anal.
Scales each with eight or ten spinelets irregularly placed, and less numerous in young
individuals, which feel bristly to the touch, separated by wide deep furrows (hence the
specific name). Seven scales in a series between the origin of the dorsal fin and the
lateral line. Teeth in the upper jaw in two series, the outer series somewhat enlarged ;
mandil)ulary teeth uniserial. Pectoral fin about half as long as the head. Brown ;
lower parts of the head and abdomen blackish.

Habitat.— Two specimens, 9 and 18 inches long, were obtained by the U.S. Fish
Commission in lat. 28° 30' N., long. 8G° 50' ^Y., and ofi" Martinique, at depths of 340
and 472 fathoms.

150 THE VOYAGE OF H.M.S. CHALLENGER.

Subgenus Nematonurus.

'^to^

Macrurus armatiis (PI. XL. fig. A). •

Macrurus armatiis. Hector, Ann. and Mag. Nat. Hist., 1875, vol. xv. p. 81.
Caryi'ihxnoides variabilis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 27.

D. 11. P. 18-20. V. 9-10.1

Snout obtusely conical, projecting beyond the mouth, the cleft of which extends
behind the middle of the eye. Teeth of both jaws in a single series. Barbel nearly as
long as the eye. The interorbital space is fiat, its width being much more than the
diameter of the eye, which is comparatively small, and in specimens 1 1 to 20 inches long-
shorter than the snout, and contained five and a half times in the length of the head.

The scales are provided with five ridges, each ridge composed of several spines, and
the central ridge being the strongest. There are eight scales in a transverse series
between the first dorsal fin and the lateral line. Lower limb of the prseoperculum scaleless.
Second dorsal spine armed with barbs in front, which are rather distantly set. The
second dorsal fin commences at a distance from the first, which is less than the lenerth of
the head. The distance between the vent and isthmus is equal to, or more than, the
length of the head. The outer ventral ray produced into a long filament.

Habitat. — Midway between the Cape of Good Hope and Kerguelen Island, Station
147 ; depth, 1600 fathoms. Three specimens, 5, 10-|^, and 22 inches long.

South Pacific, Station 146 ; depth, 1375 fathoms. Six specimens, 10 inches long.

South Pacific, Station 157 ; depth, 1950 fathoms. One specimen, 10 inches long.

South Pacific, Station 158 ; depth, 1800 fathoms. Eleven specimens, 5 to 18 inches
long.

Mid-Pacific, Station 246; depth, 2050 fathoms. Three specimens, 7 and 17 inches
long.

Mid-Pacific, Station 271 ; depth, 2425 fathoms. One specimen, 15 inches long.

Two hundred miles east of Cape Farewell ; depth, 400 fathoms. One specimen,
8f inches long. Type of Macrurus armatus.

This species has a wide range in the southern hemisphere, and is subject to some
variation, the variation occurring in individuals from the same locality, and afi'ectiug the
form of the head, length of dorsal spine, &c. The most striking deviation from the
typical form is a kind of albino, not quite white, but of a much lighter colour than the
ordinary specimens. In these albinos the scales (fig. a') are much thinner, the ridges
sometimes scarcely visible, and if developed, they are merely keels without spines. The
spines are in some specimens more projecting than in others; the specimen from
Station 271 having them most prominent.

' Not seven as stated by Hector.

EEPORT ON THE DEEP-SEA FISHES. 151

Macrurus affinis (PI. XL. fig. B).

Coryphsenoides affinis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 27.
D. 11. P. 19. V. 10.

Closely allied to Coryphsenoides armatus.

Snout obtusely conical, projecting beyond the mouth, the cleft of which extends
behind the middle of the eye. Teeth of the upper jaw biserial, those of the outer series
much stronger than the inner; mandibulary teeth uniserial. Barbel shorter than the
eye. The interorbital space is flat, its width being equal to the diameter of the eye,
which is comparatively large, as long as the snout, and one-fourth of the length of the
head. The scales are provided with five (or three) radiating ridges, each ridge composed
of several small spines, and the central ridge being the strongest. There are seven scales
in a transverse series between the anterior dorsal spine and the lateral line. Prse-
operculum with the posterior margin slightly excised above the angle, and with the lower
margin crenulated ; the lower limb of the prfeoperculum is covered with small scales in
the larger specimen, and naked in the young one. The second dorsal spine is armed
with barbs which are rather closely set. The second dorsal fin commences at a distance
from the first, which is rather more than one-half of the length of the head. Distance
between the vent and isthmus much more than the length of the head in the larger
specimen, and equal to it in the younger one. Outer ventral ray produced into a
filament. Brownish-black.

Habitat.— Esist of the mouth of the Rio de la Plata, Station 323; depth, 1900
fathoms. Two specimens, 10 and 13 inches long.

Macrurus longijilis (PI. XXXV.).

Coryphxnoides longifilis, Gunth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 439.

D. 13. P. 18. V. 9.

Head compressed, oblong, with the muciferous canals not enlarged. Snout, as m a
Gachis, swollen, obtuse, not projecting beyond the mouth, the jaws being equal. Eye rather
large, one-fifth of the length of the head, shorter than the snout, the length of which
equals the width of the flat interorbital space. Mouth very wide, anterior and lateral,
extending nearly to below the hind margin of the eye. Upper teeth biserial, those of
the outer series much stronger than the others, those of the lower strong, in a single series.
Barbel minute. Pra;operculum with the hind margin excised, with the angle rounded,

and both limbs scaly.

Scales rather thin and small, with about five feeble radiating keels. There arc
thirteen or fourteen scales in a transverse series between the first dorsal fin and the lateral

152 THE VOYAGE OF H.M.S. CHALLENGER.

line. The second dorsal spine is feeble, somewhat produced, obscurely denticulated in
front. The second dorsal fin commences immediately behind the first. Pectoral much
prolonged, as long as the head. The outer ventral ray produced into an exceedingly
long stiff filament. The distance between vent and isthmus rather less than the length
of the head. Brownish-black.

Habitat. — South of Yedo, Japan, Station 235; depth, 565 fathoms. One specimen,
28 inches long.

This species in the structure of its head and in its physiognomy approaches to the
ordinary Gadoid type.

Trachyrhynchns.

Tracliyrhynchiis, Giorna.

Snout produced into a long depressed process, sharply pointed in front, and with a
rather sharp lateral edge, which is continued in a straight line across the infraorbital
region. Mouth horse-shoe-shaped, situated at the lower side of the head. Teeth in both
jaws in villiform bands. A barbel. A scaleless fossa on each side of the nape. The
second dorsal fin well developed from its beginning. Scales of moderate size, more or less
\, spinigerous; a series of larger scales, each ax'med with a projecting ridge along each side
of the base of the anterior portions of the dorsal and anal fins. Of the gill-covers
the operculum is particularly small. GUI membranes scarcely united in front. Four
gills with well-developed gill-lamina?. The first branchial arch is free and pro-s^ided with
short styliform gill-rakers.

Trachyrhynchus trachyrhynchns (PL XLI. fig. C).

Lepidoleprus trachyrhynchus, Eisso, Ichth. Nice, p. 197, pi. vii. fig. 2L
; ,, ,, Canestr., Arch, per la Zool., 1864, p. 371, pi. xii. fig. 2.

I „ . „ Vinoiguerra, Ann. Mus. Genov., vol. xiv. p. 617; vol. xviii.

p. 564.

D. 10-11. P. 20-21. V. 7.

,■' Snout not quite twice as long as the eye, the horizontal diameter of which is much

i' greater than the vertical, about one-fourth of the length of the head, and equal to the width

! of the interorbital space above the centre of the orbit. Scales very rough, each with three

\ or four acute and prominent spines ; four series between the first dorsal fin and the lateral

line; the crests of many of the enlarged dorsal scales are coarsely denticulated. The

entire abdomen covered with scales. Distance of vent from the isthmus equal to that of

the hind margin of the eye from the extremity of the snout. Barbel very small, ^'entrals

small, inserted in front of the pectoral fin, wdth the outer ray produced into a short filament.

Anterior branchial arch with twenty -two very short, styliform gill-rakers.

r

REPORT ON THE DEEP-SEA FISHES. 163

This is a Mediterranean species, of wliicli I have examined three specimens from Nice,
from 15 to 17 inches long.

Of the two figures, the lower is a magnified view of a scale taken from the middle of
the side, the upper is a dorsal scute, likewise magnified.

Trachyrhynchus longirostris (PI. XLI. fig. B).

Macrurus longirostris, Giintli., Ann. and Mag. Nat. Hist., 1878, vol ii. p. 23.
D. 10. P. 21. V. 6.

The snout is produced into a long flattened process, pointed anteriorly, and not quite
twice as long as the large eye. Horizontal diameter of the eye about twice as long
as vertical, more than one-fourth of the length of the head, and equal to the width of the
interorbital space above the centre of the orbit. Head covered with short, linear, serrated
asperities. Scales of the body with smooth surface, but with from three to seven
spinelets on the margin. They are rather irregularly arranged, there being four in a
transverse series between the lateral line and dorsal fin. A series of projecting
triangular spines along each side of the neck and the base of the anterior portion of the
dorsal fin; a similar series along each side of the base of the anal extends much farther
backwards than the dorsal series, and anteriorly is lost on the side of the abdomen.
These spines have smooth edges (not denticulated, as in Macrums trachyrhynchus).
The entire abdomen covered with scales. Outer ventral ray produced into a short
filament. Anterior branchial arch with about twenty short gill-rakers.

Habitat. — North-east of New Zealand, Station 169 ; depth, 700 fathoms. Two
specimens, 20 inches long.

These specimens were caught on the 10th of July, which, although mid-Avinter in that
southern latitude, seems to be the season of propagation. The ovaries are closed sacs,
the ova of the size of millet-seed.

The lower figure represents a scale from the middle of the side, the upper a dorsal
scute; both magnified.

Trachyrhynchus murrayi, n. sp. (PI. XLI. fig. A).

D. 9. P. 23. V. 7.

The large orbit is oval in shape, nearly one-fourth of the length of the head, contained
once and two-thirds in the length of the snout, and equal to the width of the interorbital
space above the middle of the orbit. Scales almost smooth, having one, two, or three
small spines developed on their hind margin; they are rather u-regularly arranged, in four

(ZOOL. CHALL. ESP. — PART LVH. — 1886.) Lll 20

154 THE VOYAGE OF H.M.S. CHALLENGER.

series between the dorsal fin and the lateral line; crests of the dorsal scales simple,
triangular, spines directed backwards, without denticulation. The abdomen between the
vent and the roots of the ventral fins scaleless. The distance of the vent from the
isthmus nearly equal to that of the hind margin of the eye from the extremity of the
snout. Barbel minute. Ventral fin very small, scarcely in front of the pectoral, with
the outer ray produced into a filament, which does not reach the vent. Pectoral as long
as the postorbital portion of the head. Anterior branchial arch with twenty-two very
short styliform gill-rakers.

Light yellowish (in spirits): vertical fins, ventral filament, interior of the mouth and
branchial cavity black.

This species was discovered by Mr. John Murray during the cruise of the " Knight
Errant" in the Faroe Channel, at a depth of 555 fathoms (Station 4, August 10, 1880).
Four specimens were obtained ; the two larger are 1 4 and 1 5 inches long, and the two
smaller ones 8 and 10 inches. The latter, being the younger, differ from the former, as
usual, by a relatively somewhat larger eye and a somewhat shorter abdomen.

Bathygadus.

Bcdhyrjadus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 23.

'^" Head short, thick. Snout not projecting beyond the mouth; jaws even in front.

Mouth wide, anterior and lateral. Eye small. Teeth in both jaws villiform, in narrow

bands, which occupy the whole length of the jaws. Barbels present or absent. The two

dorsal fins are almost continuous, and the anterior rays of the second are not shortened,

■^v; , but gradually diminish in length in the narrow posterior jjortion of the tail. Anal rays

feeble. Bones of the head cavernous, soft, without prominent ridges. Scales small,

, cycloid, deciduous. Three and a half gills only, there being no slit behind the fourth

' arch; gill-lamina3 very short. The first branchial arch quite free, with numerous long,

-, setiform gill-ralcers.

Bathygadus cottoides (PI. XLII. fig. A).

Bathygadus cottoides, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 2.3.

D. 8. P. 10. V. 8-9.

The head is large, thick, and in the nuchal region of considerable depth. Nothing
can be said of its integuments, which are lost, leaving the bones and cavities bare. The
muciferous channels are of great width, formed of very thin bone. The eye is small,
situated anterior to the middle of the length of the head, about one-sixth of its length, one-
half of the length of the snout and of the width of the interorbital space. Snout broad.

REPORT ON THE DEEP-SEA FISHES. 155

with the mouth oblique, opening anteriorly, and extending backwards to below or beyond
the middle of the eye. Gdl-openings very wide, the gill-membranes being united for a
short distance only, leaving the greater part of the isthmus uncovered. Branchiostegals
six. Barbel none. The margin of the praeoperculum is much dilated, forming a
semicircular disk, and, like the other bones of the gill-apparatus, membranaceous.

The first dorsal fin commences immediately above the root of the pectoral; its rays
are very thin and fragile, not much longer than the anterior of the second dorsal, which
commences immediately behind the first. The rays of the second dorsal are throughout
much more developed than those of the anal. Base of the pectoral narrow ; its rays
]>eing extremely thin and delicate, and the upper prolonged into long filaments, the
longest of which extends to the anal. Ventral fins below the pectoral.

The distance between the vent and base of the ventral equals about half the length of
the head. Nearly all the scales are gone, but the few which remain show that they were
cycloid. There appear to have been six in a transverse line between the first dorsal fin
and the lateral line.

Brownish-black. Head, abdomen, and inside of mouth, deep black. First branchial
arch with 6-f-17 long, setiform gill -rakers (see figure).

Habitat. — Deep-sea, between New Zealand and the Kermadec Islands, Station 169;
depth, 700 fathoms. One specimen, 8 inches long.

Near the Kermadec Islands, Stations 170, 170a ; depth, 520 and 630 fathoms. Seven
specimens, 4 to 7 inches long.

Near the Kermadec Islands, Station 171; depth, 600 fathoms. Six specimens,
2 to 2^ inches long.

All the specimens of this interesting new form of Macruridse were unfortunately
much damaged by the trawl.

Bathygadus multifilis (PL XLII. fig. B).

D. 8. P. 15. V. 8.

The head is compressed, and rather elongate ; the nuchal region not being elevated.
The muciferous channels are less capacious, and the bones are generally firmer than in
Bathygadus cottoides. Eye of moderate size, oval, much longer than deep, its longest
diameter being two-ninths of the length of the head, equal to the length of the snout
and to the width of the interorbital space. Snout rather obtuse, with the mouth veiy
wide, oblique, opening anteriorly, and extending backwards to behind the eye. Gill-
openings as in Bathygadus cottoides. Barbel long, half the length of the head. The
margin of the prteoperculum is but slightly dilated, with the angle rounded.

The first dorsal fin commences above the root of the pectoral, the second ray, as well

156 THE VOYAGE OF H.M.S. CHALLENGER.

as the first of the pectoral, and the outer of the ventral, is feeble, but produced into very
long filaments. The rays of the second dorsal, which commences immediately behind the
first, are throughout much more developed than those of the anal. Base of the pectoral
narrow, not broader than that of the ventrals. Ventral fins below the pectoral. The
distance between the vent and base of the ventral equals about half the length of the head.

Nearly all the scales are lost, but there appear to have been six in a transverse line,
between the first dorsal fin and the lateral line. Gill-rakers 5 + 24, long, slender,
setiform.

Brownish, with the lower part of the head and the inside of the mouth deep black.

Habitat. — South of the Philippine Islands, Station 214 ; depth, .500 fathoms. One
specimen, 5 inches long.

Bathygadus cavernosus.

Bathygadus cavernosus, Goode and Bean, Proc. U.S. Nat. Mus., 1886, vol. viii. p. .598.

D. 12. P. ? V. 11.

The eye is much longer than the snout, more than one-third of the length of the
head, and equal to the width of the interorbital space. Barbel not quite half as long as
the eye. Pectoral about two-thirds of the length of the head. Outer ventral ray
produced, and reaching beyond the origin of the anal.

The single specimen obtained is quite young, and only 6^ inches long. As its gill-
rakers are described as " very short, minute, and rather numerous," and the second dorsal
fin as " almost rudimentary " and composed of " remarkably short rays," it is very
improbable that this fish belongs to Bathygadus, It was caught by the U.S. Fish
Commission in the North Atlantic; lat. 28° 45' N., long. 86° 26' W.

Bathygadus macrops.

Bathygadus macrops, Goode and Bean, Proc. U.S. Nat. Mus., vol. viii., 1886, p. 598.

D. 10. P. ■? V. 8.

The eye is much longer than the snout, exceeds the width of the interorbital space,
and is more than one-third of the length of the head. Maxillary extending to below the
hind margin of the eye. Barbel minute. The longest dorsal spine is not quite half as
long as the head; anterior rays of the second dorsal well developed, and longest. Pectoral
fin as long as the head, without snout ; ventral reaching nearly to the vent. Gill-rakers
lanceolate, elongate, 7 -I- 26. Yellowish-grey. «

The scales were lost, but about twenty-five rows could be counted in an oblique line
from the vent to the dorsal fin.

Habitat. — A specimen, 12 inches long, was taken by the U.S. Fish Commission in
lat. 28° 34' N., long. 86° 48' W., at a depth of 335 fathoms.

REPORT ON THE DEEP-SEA FISHES. 157

Bathygadiis longijilis.

Balhygadus longijilis, Goode and Bean, Proc. U.S. Nat. Mus., vol. viii., 1886, p. 599.
D. 10-11. P. 13. V. 8.

The eye is one-fourth of the length of the head, equal to that of the snout, and rather
less than the width of the interorbital space. Maxillarj^ extending somewhat behind the
eye. Barbel longer than the eye by one-half The anterior dorsal spine, the upper
pectoral ray, and the outer ventral ray produced into long filaments. About twenty-five
scales in a row from the vent upwards and forwards to the dorsal fin. Gill-rakers very
long and slender, 7 -I- 28. Yellowish -grey ; abdomen bluish.

Evidently closely allied to Batliygadus nmltijilis.

Habitat. — Specimens were obtained by the U.S. Fish Commission in lat. 28° 47' N.,
long. 87° 27' W., at a depth of 724 fathoms ; they were 8 inches long.

Macruromts.

Macruromts, Giintli., Zool. Record, vol. viii., 1873, p. 103.

Head and body compressed, covered with cycloid scales ; trunk not abbreviated.
Bones of the head rather firm, with narrow cavities. Eye large ; snout rather pointed ;
mouth wide, lateral. Teeth in the upper jaw biserial, those of the outer series and those
of the single maudibulary series strong. Gill-membrane slightly united in front ; seven
branchiostegals ; four gills with the gill-laminse well developed ; the first branchial arch
free, with long lanceolate gill-rakers. Rays of the second dorsal well developed throughout
its length. Barbel none.'

o"

Macruronus novse-zelandise.

Coryphsenoides novx-zelandix, Hector, Trans. New Zeal. Inst., vol. iii. p. 136, pi. xviii. fig. 1 ;

Button, Fish. N. Z., p. 49.

Of this fish I have examined specimens from New Zealand, Tasmania, and the Messier
Channel, the largest being nearly 2 feet long. All of them seem to have been caught
near the surface and at no great distance from the shore, and it is not probable that
it descends to the same great depth as the other Macruri. Like Lepidoj:)^, it seems to
live for the greater part of the year at a small depth, and to periodically approach the
shore at certain seasons. Hutton says that it is thrown up in large quantities on the
shores of Cook Straits after heavy gales.

1 Both Hector and Hutton describe or figure this fish with a barbel, whiLst I cannot detect a trace of it i:i our
specimens. Some misunderstanding by the artist must have occurred, as, at any rate, the bifid barbel could not be at
the place where he has drawn it.

158 THE VOYAGE OF H.M.S. CHALLENGER.

,^ ' Family Lyconidje.

Body terminating in a long compressed tapering tail, covered with small scales. A
continuous dorsal fin occupies the back to the extremity of the tail, but a division into two
portions may be considered to be indicated by the prolongation of some of the anterior
dorsal rays; anal long, extending from the vent to the end of the tail ; no caudal; ventrals
thoracic, composed of several rays. Pseudobranchise present ; four gills ; seven
branchiostegals.

I am obliged to propose a distinct family for the new genus described below,
as it differs in certain characters from the Macruridaj, by which this latter family has
hitherto seemed to be well defined. It may be considered to be a more generalised type
than the Macruridse.

Lyconus, n. gen.

Head and body compressed, the former composed of thin bones, but with narrow muci-
ferous channels, except on the top between the eyes ; trunk as long as or longer than the
head; eye large ; snout short; cleft of the mouth wide, terminal, both jaws armed with a
series of widely set teeth unequal in size ; two in front of the upper jaw being canine-like
but not so large as those of the lower jaw ; vomer with a single canine-like tooth on each
side. Scales very small, cycloid, deciduous. Gill-membranes not united. Barbel none.

Lyconus pinnatus, n. sp. (PI. XLII. fig. C).

Head compressed, as deep as it is long, without snout. The iuterorbital space is
rather flat, narrower than the round eye, which lies immediately below the upper profile ;
its diameter is one-third of the length of the head and rather longer than the snout. The
mouth ascends obliquely forwards, and extends behind the middle of the orbit ; the jaws
are even in front. The teeth are but few in number, and besides the two long lateral fangs
there are only three shorter ones developed in the lower jaw. Opercular bones very thin,
and the infraorbitals narrow, separating the maxilla from the eye by a narrow space only.

The distance of the vent from the root of the ventrals is rather more than the length
of the head. The tail tapers into an exceedingly fine filament.

The dorsal fin commences above the base of the pectoral, and is composed of very
delicate simple rays ; there is no break in its continuity, but some of its anterior rays,
perhaps three or four, are much prolonged, but as this portion is injured, no more precise
information can be given. The anal fin commences immediately behind the vent, and
Its rays are considerably shorter than those of the dorsal. The pectoral has a narrow base,
and is obliquely directed upwards; it consists of thirteen rays, and is exceedingly elongate,
tlie middle rays extending far beyond the vent.

REPORT ON THE DEEP-SEA FISHES. 159

The ventral fins are mutilated ; they are composed of ten rays and situated below
the base of the pectoral.

Scales very small, thin and deciduous.

The total length of the specimen is 59 lines, of which the head takes 7, and the
head and trunk together 17.

The single si^ecimen was acquired for the British Museum in 1876 from the Godetfroy
Museum, but I deferred its description, in the hope that the Challenger collection might
supply some additional materials. But as it has remained unique, it seems that it is an
extremely rare species. The specimen was picked up in mid-ocean in the South Atlantic,
in the depths of which adult examples will be probably discovered at some future time.
It is not likely that the principal characters given here will be found to undergo essential
changes with age.

Family Ateleopodid/E.
Ateleopus, Schleg.

Body and tail compressed, scaleless, the latter much elongate, band-shaped ; head
oblong, with rather long and broad snout, the end of which overlaps the mouth ;
maxillaries protractile in a downward direction. Bones of the head and body soft,
semicartilaginous, those of the snout enclosed in a thick, mucigerous skin. One short-
rayed dorsal fin on the trunk, a narrow, skinny, rayless fringe occupying the remainder of
the back. A long anal begins behind the vent, and is continuous with the caudal.
Ventral fins reduced to filaments, and inserted immediately behind the symphysis of the
clavicles. Eyes of moderate size, with small horizontal pupil. Teeth villiform, in narrow
bands ; none on the palate. Trunk as long as the head. Gills four, separate ; pseudo-
branchiae none.

One species only is known. ■

Ateleopus japonieus (PI. L. fig. A).

Ateleo^ncs, Schleg., Faun. Japon. Poiss., p. 25.5, pi. cxii. lig. 1.

Ateleopus japo7ikus, Bleek., Verhandl. Batav. Genootscb., vol. xxv. Nalez. Japan., p. 19.
„ „ Giintli., Fish., vol. iv. p. 398.

B. 9. D. 8. A + C. 110. P. 12. V. 2.

The length of the head equals that of the trunk, and is one-seventh of the total. The
head is rather thick, low and oblong, with broad, flat, slightly dechvous upper surface.
The eye is a little nearer to the extremity of the snout than to the end of the gill-cover,
immediately below the upper profile, about half the length of the snout. The entire head

160 THE VOYAGE OF H.M.S. CHALLENGER.

is enveloped in soft skin, wliicli is thickest and miicigerous on the snout ; no foramina
leading into the muciferoiis system can be distinguished. The nostrils lie immediately
in front of the eye.

The thick end of the snout overlaps the mouth, which is horse-shoe-shaped, its lateral
cleft extending to the front margin of the eye. Barbel none.

The branchial cleft extends from the upper end of the gill-cover far forwards, the
brauchiostegous membranes being free from each other. Gill-laminse well developed ;
gill-rakers rather short, soft, lanceolate.

All the fins arc long-rayed. The dorsal fin has a rather broad base, the length of
which is about one-third of its distance from the end of the snout ; it is very high, its
longest rays being much longer than the head, and even exceeding the pectoral fin. As
regards the anal fin, the rays of its anterior portion are about equal to the depth of the tail,
but the posterior increase in length, and exceed much the gradually decreasing depth of the
tail. The pectorals have a narrow base, are longer than the head, and extend backwards
to the origin of the anal. The ventrals consist of two rays each, of which the longer is
bifid at the end, and nearly reaches the vent ; the shorter and inner is rudimentary.

The fish is nearly transparent, with a brownish tint ; dorsal and pectoral fins and a
broad mai'sjin of the anal black.

'&'

I am indebted to M. Tegima of the Tokio Museum for a specimen of this extremely
rare fish, which does not seem to have been observed since it was described in the
Fauna Japonica. It is 9 inches long, and in a good state of preservation, except for a
certain degree of desiccation, which it has undergone in consequence of the action of the
spirit on the mucous layer with which it is covered. Our specimen diff"ers in the shape of
the fins from the figure given by Schlegel. Perhaps this is due to age, as the specimen
of the Dutch naturalist was considerably larger.

Family Ple qronectid^.^

As far as our present knowledge goes. Flat-fishes are, unlike the Gadoids and Ophi-
dioids, but sparsely rejjresented in the deep sea, and have not yet reached to a depth of

' For the sake of completeness I mention here a small Flat-fish, 72 mm. long, which was ohtainetl hy the U.S. Fish
Commission at depths of 86 and 115 fathoms, in lat. 40° 0' N., long. 70° 23' AV., and which has been described by Mr.
Brown Goode under the name of Thyris or Delothyris pellucidus (Proc. U.S. Nat. Miis., vol. iii. p. 344, 1 880 ; and p. 1 10,
1884), and which both he and Mr. Jordan regard as a larval form. As generic diagnosis the following description is
given : — " A genus of heterosome fishes, with soft, transparent, elongate body. Head very short (in the single species
contained about 5i times in total length of body). Mouth small, toothless. Eyes upon left side, close together, the
lower slightly in advance of the upper. Pectoral flu upon blind side shorter and with fewer rays than upon coloured
side. Ventrals crowded together upon median keel of body, their bases prolonged upon this keel. Dorsal fin com-
mences iu front of the eye upon the snout. Dorsal and anal rays simple. Caudal fin subsessile, almost confluent with
dorsal and anal. Scales very small, thin, easily detached. Dorsal line marked, straight. Body translucent, colourless
(except for three longitudinal stripes in the single species). The vertebra? can almost be counted through the flesh when
the fish is held up to the light, and the arrangement of the gills is clearly visible through the opercular bones."

REPORT ON THE DEEP-SEA FISHES. 161

800 fathoms. Neither does this family ofTer a striking instance of bathybial organisa-
tion, for although the majority of the species are distinct from the surface forms, their
distinctive characters are such as may be also observed among the latter. The number
of Flat-fishes of which we have certain indications of their living or occurring beyond 100
fathoms, is only nineteen ; and four of them are identical with species which have been
long known as littoral inhabitants ; one of them descends to 100, the second to 220, a
third to 447, and the fourth {Pleuronectes cynoglossus) to 732 fathoms, the furthest limit
of the vertical distribution of the Pleuronectoid type. The other fifteen species are
either generically or specifically distinct from surface forms, ten having been found
between 100 and 200 fathoms, two between 200 and 300 fathoms, and three between
300 and 400 fathoms.

Hippoglossus, Cuv.

Hippoglossics pinguis, Fabr.

Hippoglossus pinguis, Collett, Norges Fisk, p. 135.

Platysomatichthys hippoglossoides (Walb.),Goode and Bean, Bull. Ess. Inst., vol. xi. p. 7, 1879.

„ „ Collett, Norsk. Nordh. Exped. Fisk., p. U2.

Hippoglossus groenlandicus, Giintli., Fish., vol. iv. p. 404.

An Arctic species, extending southwards to the deep water off the coast of Massa-
chusetts, in the Western Atlantic ; found in a single young example by the North
Atlantic Expedition, south-west of Bear Island, in 447 fathoms, and occasionally obtained
from deep water on the coast of Norway.

Hippoglossoides, Gottsche.
Hippoglossoides platessoides (Fabr.).

Hippoglossoides platessoides, CoUett, Norsk. Nordh. E.\ped. Fisk., p. 145.
„ „ Goode, Proc. U.S. Nat. Mus., vol. iii. p. 471.

An inhabitant of the northern seas, from the coast of Scandinavia to that of North
America, southwards to New England, and living in shallow water in the vicinity of
land. Collett reports its occurrence at depths of from 120 to 220 fathoms south of
Spitzbergen and Bear Island. Goode .states that it is not unusual in deep water off
Southern Massachusetts and Rhode Island.

(ZOOL. CHALL. EXP. — PAET LVII. — 1887.) ^^^ 21

IQ2 THE VOYAGE OF H.M.S. CHALLENGER.

Poecilopsetta, Gthr.
Only one species is known.

Pcecilopsetta colorata.

Poecilopsetta colorata, Gunth., Eeport on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 48, pi. xxii.
fig. B.

Habitat. — Ki Islands, Station 192 ; depth, 129 fathoms. Two specimens.

Anticitharus, Gthr.
One species only is known.

Anticitharus polyspilus.

Anticitharus polyspilm, Giinth., Eeport on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 48,

pi. xxii. fig. A.

Habitat. — Ki Islands, Station 192; depth, 140 fathoms. Two specimens, 7 and 8^
inches long.

Samaris, Gray.

Two species are known, of which one occurs in the Chinese Seas, and is probably
littoral ; the other is —

Samaris maculatus.

Samaris maculatus, Giinth., Report on the Shore Fishes, Zool. Chall. Exp., pt. vL p. 47, pi. xxi.
fig. A.

Habitat. — Ki Islands, Station 192 ; depth, 140 fathoms. One specimen, 4 inches long.

Lepidopsetta, Gthr,
Known from a single specimen only.

Lepidopsetta maculata.

Lepidopsetta maculata, Giinth., Report on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 18,
pi. XXX. fig. C.

Habitat. — Oflf Prince Edward Island, Station 145a; depth, 310 fathoms. One
specimen, 5^ inches long.

REPORT ON THE DEEP-SEA FISHES.

163

Fseudorhombus, Blkr.

Dr. Hector lias kindly sent to me the specimen from 400 fathoms which was given
him by Sir Wyville Thomson for description, and which served as a type of his Pseudo-
rhombus hoops. On comparing it with the second specimen from 150 fathoms, brouo-ht
home by the expedition as a "co-type" of that species, and consequently described by
me under the same name in Shore Fishes, p. 26, I find considerable differences in the
proportions of various parts of the head ; difi'erences which are quite in accordance with
the depths at which the two specimens were found, and which are sufficiently developed
to call for specific distinction. I give here comparative descriptions and figures of the
heads of both specimens, from which it will be seen how far the development of bathybial
characters has proceeded in the specimen from the greater depth.

Pseudorhombus hectoris.

Pseudorhonihus hoops, Giinth., Report on the Shore Fishes, Zool. Chall. Esp., pt. vi. p. 26 (not
Hector).

D. 117. A. 89. P. 12. L. lat. 78.

The dorsal fin commences above the nostrils. The height of the body is two-fifths of
the total length (without caudal), the length of the head nearly one-fourth. Scales
ciliated ; those on the head and on the anterior part of the body smaller than those on

Fig. 4. — Head of Pseitdorhmitims hectoris.

Fio. 5.— Head of Pseudorhombus boops.

the tail. Interorbital ridge very narrow and naked. No spines or tubercles along
the lateral line or the base of the fins. The curve of the lateral line is strong, but flat
above. Snout rather shorter than the eye, the diameter of which is two-sevenths of the
length of the head. Lower jaw scarcely prominent when the mouth is shut. The

164 THE VOYAGE OF H.M.S. CHALLENGER.

maxillary extends beyond the front margin of the eye, and is two-fifths of the length of
the head. Lower eye considerably in advance of the upper. Lower liml) of the pr^e-
operculum half as long as the head. Vertical fins of moderate height, extending nearly
to the root of the caudal. Left pectoral fin more developed than the right, and rather
more than one-half of the length of the head. Brownish ; fin-rays indistinctly punctulated
with brown.

Habitat. — Off the coast of New Zealand, Station 167 ; depth, 150 fathoms. One
specimen, 6 inches long.

Pseudorhomhus hoops.

Pseudorhomhus loops, Hector, Trans. New. Zeal. Inst, vol. vii. p. 249, pi. xi.

D. 111. A. 92. P. 13. L. lat. 80.

The dorsal fin commences above the nostrils. The height of the body is contained
twice and three-fourths in the total length (without caudal), the length of the head
thrice and three-fifths. Scales indistinctly ciliated ; those on the head and on the
anterior part of the body smaller than those on the tail. Interorbital ridge very
narrow and naked. No spines or tubercles along the lateral line or the base of the fins.
The curve of the lateral line is strong, but flat above. Snout two-thirds of the length
of the eye, the diameter of which is two-sevenths of the length of the head. Lower jaw
prominent. The maxillary extends nearly to below the middle of the eye and is two-
fifths of the length of the head. Lower eye considerably in advance of tlie upper.
Lower limb of the prseoperculum rather more than half as long as the head. Vertical
fins of moderate height, extending nearly to the root of the caudal. Left pectoral fin
more developed than the right and somewhat more than one-half of the length of the
head. Uniform yellowish-white.

Habitat. — Two hundred miles ofi" Cape Farewell ; depth, 400 fathoms. One
specimen, 6 inches long.

Pseudorhomhus ohlongus (Mitch.).

ParalichtJiys oblongus, Goode, Proc. U.S. Nat. Mus., voL iii. p. 472.

A littoral species, off" the United States, taken in 100 fathoms, on the south coast of
New England.

o

Pseudorhomhus oceUatus.

Pseudorhomhus oceUatus, Giinth., Report on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 56,

pi. xxiv. figs. A, B.

Habitat. — Admiralty Islands ; depth, 152 fathoms. One specimen, 5 1 inches long.

REPORT ON THE DEEP-SEA FISHES. 165

Rhomhoidichthys, Blkr.

This genus includes littoral species of tlie Tropical and Subtropical seas, and there is
also some uncertainty as to the depth at which the following species was obtained.

Rhomboidichikys cornutus.

Rhomhoidichthys cornutus, Giinth., Report on the Shore Fishes, Zool, ChalL Exp., pt. vi. p. 7,

pi. ii. fig. B.

Hahitat. — Coast of Brazil, Stations 122 to 122b; depth, 32 to 350 fathoms. One
specimen, 3^ inches long.

Monolene.

Monolene, Goode, Proc. U.S. Xat. Mus., vol. iii., 1881, p. 338.

This genus seems to differ from Arnoglossus by having a narrower mouth, the
length of the maxillary being less than one-third of that of the head, by the total
absence of the pectoral fin on the blind side, and by feeble gill-rakers in small number.

Monolene sessilicauda.

Monolene sessilicauda, Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, pp. 338, 472; Bull. Mus.
Comp. Zool., vol. X., 1883, p. 194.

D. 99-103. A. 79-84. L. lat. 92 (?).

Several specimens, from 4 to 6 inches long, were obtained by the U.S. Survey
steamers, in lat. 40° 0' N., long. 70° 22' W.; and in lat. 32° 31' N., long. 78° 44'
W.; at depths from 115 to 155 fathoms.

Citharichthys, Blkr.

The species of this genus are littoral forms, from the Tropical Atlantic and California,
but the following have descended to moderate depths within the same oceanic area.

Citharichthys arctifrons.

Citharichthys arctifrons, Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, pp. 341, 472; BuE

Mus. Comp. Zool., ser. 5, vol. x., 1843, p. 194.

Numerous specimens, from 3| to 5^ inches long, were obtained by the U.S. Fish
Commission, at lat. 40° 0' N., long. 70° 23' W.; in from 86 to 155 fathoms;
and by the U.S. steamer " Blake," in the same area down to 197 fathoms.

166 THE VOYAGE OF H.M.S. CHALLENGEE.

Citharichthys unicornis.

Cithariehthys unicornis, Goode, Proc. U.S. Nat. Mus., vol. iii,, 1881, p. 342.

Specimens, 2| inches long, were obtained by the U.S. Fish Commission, in lat.
40° 0' N., long. 70° 22' W., in 115 and 155 fathoms.

Pleuronectes, Gthr.
Pleuronectes heanii.

Limanda heanii, Goode, Proo. U.S. Nat. Mus., vol. iii., 1880, p. 473.

Two specimens, 5 inches long, were obtained by the U.S. Fish Commission, in lat.
40° 0' N., long. 70° 23' W., at depths varying from 120 to 126 fathoms.

Pleuronectes cynoglossus, Linn.

Olyptocephalus cynoglossus, Goode, Proc. U.S. Nat. Mus., vol. iii., 1880, p. 475 ; Bull. Mus.

Comp. Zool. ser. 5, vol. x., 1883, p. 195.
„ „ Collett, Norsk. Nordh. Exped., risk., p. 150; ForhandL Vidensk.

Selsk. Christ., 1880, p. 82.
„ „ Strom, Norsk. Vidensk. Selsk. Skriv., 1884, p. 39.

The occurrence of this littoral species at considerable depths is a very remarkable
fact. The U.S. Fish Commission and the U.S. steamer "Blake" found specimens
between lat. 34° and 39° N., and between long. 70° and 75° W.; at depths of 120,
263, 395, 603 and 732 fathoms; and the North Atlantic Expedition met with the
species near Lofoten and Finmark, at 125 to 150 fathoms. Strom has caught it in
Trondhjem Fjord to a depth of 200 fathoms.

Nematops, Gthr.
Known from the following species only : —

Nematops microstoma.

Nematops microstoma, Giinth., Report on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 57,
pi. xxiv. fig. C.

Habitat. — Admiralty Islands; depth, 152 fathoms. One specimen, 3f inches
long.

Solea, Gthr.

Of the numerous species of Soles one species only is at present known to descend
beyond a depth of 100 fathoms, viz. : —

REPORT ON THE DEEP-SEA FISHES. 167

Solea kaiana.

long,

Solea kaiana, Giinth., Report on the Shore Fishes, Zool, Chall. Exp., pt. vi. p. 49, pi. xxi.

fig. C.

Habitat. — Ki Islands, Station 192; depth, 140 fathoms. One specimen, 4^ inches

Aphoristia, Kaup.
Aphoristia nehulosa.

Aphoristia nehulosa, Goode and Bean, Bull. Mus. Comp. Zobl, ser. 5, vol x., 1883, p. 192.

Habitat. — One specimen, Z\ inches long, was obtained by the U.S. steamer " Blake,"
in lat. 32° N., long. 78° 37' W.; at a depth of 229 fathoms.

PHYSOSTOMI.
Family Sternoptychid^.'
Argyropelecus, Cocco.
Argyropelecus hemigymnus, Cocco.

Common in the Mediterranean and neighbouring parts of the Atlantic, and frequently
caught at night in the surface net. During the cruise of the " Porcupine " an adult
example was obtained between Shetland and Faroe, at a depth of 180 fathoms. It
would therefore appear that this fish is of nocturnal habits, living during the day at
a depth from the surface, which varies according to circumstances.

It is also reported by Messrs. Goode and Bean among the fishes obtained by the
U.S. steamers "Blake" and '-'Fish Hawk," at depths of 225 and 245 fathoms.''

Argyropelecus olfersii, Cuv.

This species, like its congeners, has been hitherto considered to be a pelagic species of
the Atlantic, which now and then is found as far north as the coast of Norway. But
the naturalists of the Challenger obtained a specimen, 21 inches long, at Station I. (ofl
Cape Finisterre), by the dredge, which had reached a depth of 1125 fathoms.

> If Mr. Jordan (Cat. Fish. N. Amer., p. 45) takes exception to the expression which I have used (Cat. Fish., vol.
V. p. 384) in the diagnosis of this family, " a rudimentary spinous dorsal fin," and explains that " this appearance is due
to the projection of one or more of Ihe several spines Ijeyond the muscles, and is in no proper sense a rudiment of a
fin,"— he sliould have added that this explanation of the terra used was first given by myself {loc. ciL, p. 385). In the
diagnosis of the genus Argyropelecus, which he copies from my worli, he has introduced (probably by a slip of the pen)
a misleading error in describing the gill-opening as " very short," whilst, in fact, it is " very wide.

' Bull. Mus. Com}]. Zoo!., vol. x., 1883, p. 220.

168 THE VOYAGE OF H.M.S. CHALLENGER.

The question arises whether the fish was really captured at this great depth, or
whether it entered the dredge during its passage through the surface strata ; and I am
very much inclined to think that the latter took place. We have very little positive
information as to the habits of these fishes, but we know that they are commonly
obtained near the surface in mid-ocean ; and from their structure we may infer that,
like all deep, compressed fishes, they are slow swimmers, and that they can with ease
maintain a free position in the water, without the necessity of a support, remaining as it
were suspended at a certain distance from the surface. This may be observed in a fish
of our own seas with a similarly elevated Iwdy, viz., the John Dory, in which, however,
a rapid undulatory movement of the soft dorsal fin is almost unceasing. The great
development of the luminous organs, combined with the large eyes, indicates the
nocturnal habits of the fish, which would induce it to descend to a greater depth
during daytime. Also the firm structure of the bones disproves the bathybial habits
of Argyropelecus.

Sternoptyx (Herm.).

Body much elevated and compressed, passing abruptly into a short and compressed
tail ; the angle made by the hind margin of the trunk and the lower edge of the tail
being filled up by a broad fold of the integument, of peculiar transparent aj^pearance,
resembling thin cartilage. This fold bears the anal fin and is supported by interhsemal
rays. The greater portion of the body is scaleless, and covered with a silvery pigment.
A series of luminous spots runs along the lower edge of the abdomen, and is separated
from that of the other side by a cartilaginous fold occupying the median line of the
abdomen ; another series runs on each side of the isthmus ; a row of three above and
behind the root of the ventrals, and another row of three above the vent. The luminous
organs on the lower part of the tail consist anteriorly of a row of four, of which the first
is prolonged towards the back as a narrow band, terminating about the middle of the
depth of the body in a globular black spot with a white centre : posteriorly in front of
the caudal rays there is another row of four small spots.

Head short, compressed, deep, with extremely short snout and a wide subvertical
mouth. Bones of the head firm, some of them terminating in short spines, namely, the
angle of the pr^operculum, the postero-inferior angle of the mandible, and the symphysis
of the humeral bones. The margin of the upper jaw is formed by the maxillary and
intermaxillary, the latter being very short ; both these boucs have a sharp edge which
is armed with a series of very small teeth, somewhat unequal in size ; lower jaw
with a similar dentition ; vomer and palatine bones toothless. Eyes large, lateral.

REPORT ON THE DEEP-SEA FISHES. 169

Pectorals well develoj^ed, close to the lower profile ; ventrals small ; pelvic bone with a
bifid spine in front pointing forwards. The dorsal fin occupies the middle of the back and
consists of a triangular bony lamella, very thin in front, but strengthened along its
hind margin, and followed by several rays. Adipose fin absent, or represented by
a very low membranous fringe of the dorsal margin of the tail. The anal fin is
incompletely developed, extending from the vent to the root of the caudal fin, its rays
being rudimentary, widely set, and scarcely free. Caudal fin broad and forked. Gill-
opening very wide, the gill-membrane being attached to the isthmus. A luminous organ
occupies the inner side of the operculum close to its lower end ; another is placed at the
anterior end of the ceratohyal, and, finally, a very large glandular mass is lodged on
the upper edge of the anterior end of the clavicle. Gills four ; the branchial arches are
long, not angularly bent, the branchial slits being closed by a membrane in their upper
portion. Only a few of the gill-rakers are prolonged, needle-shaped, and widely set, the
others being quite rudimentary. Pseudobranchia present.

Sternoptyx diaphana (Herm.) (PI. XLV. figs. D, D').

D. 10 to 12. A. 12. P. 10. V. 3.

The numerous specimens collected by the Challenger difi'er not inconsiderably in the
shape of the body, which in some specimens is much more oblique than in others ; in the
width of the upper surface of the head and neck, and, finally, in the size of the eye, which
in a specimen 50 mm. long is 8 mm. w^de, and in another specimen of the same length
only 7 mm. Also the relative position of the luminous organs which are congregated in
groups, is subject to unimportant variations.

Two forms may be distinguished.

1. In the fii-st and more common (fig. D), the eye is comparatively larger and its
diameter more than the depth of the triangular space, which is formed by the margins of
the prseoperculum, of the jaws, and of the orbit ; the upper part of the mouth is also
conspicuously above the level of the lower margin of the orbit.

2. In the second form (fig. D'), the diameter of the eye is not longer than the depth
of the triangular space described, and the upper part of the cleft of the mouth is on a
level with the lower margin of the orbit.

Both forms occur in the Indo-Pacific as well as Atlantic, and seem sometimes to have
been obtained on the same occasion ; and as, moreover, intermediate forms occur which
might be assigned to either of the two forms, it is evident that the differences mentioned
are not of specific value.

Very young specimens of 15 mm. in length already possess all the characteristics of
the adult.

As will be seen from the following list of specimens obtained during the voyage, this

(ZOOL. CHALL. EXP. — PAET LVII. — 1887.) ■'^^^ ''•'

170 THE VOYAGE OF H.M.S. CHALLENGER.

species would appear to inhabit all depths from the surface downwards. This is
extremely improbable, and its frequent capture is only a proof of its abundance in all
tropical seas, and of the slowness of its movements, which prevent it from getting out
of the way of the dredge or net. Like Argyropelecus it is a pelagic fish, which
probably lives in shoals, as sometimes more than one example were obtained in the same
haul. Possibly it may descend to or beyond the 100 fathoms line during the day-time.

Messrs. Goode and Bean have included this species in their Eeport on the " Blake "
collection, from depths of 229 and 457 fathoms.^

Habitat. — Between Tenerife and St. Thomas ; surface. Two specimens, f and 1
inch long.

OflP Sierra Leone, Station 101 ; depth, 2500 fathoms. One specimen, ^ inch long.

Mid Atlantic, Station 106 ; depth, 1850 fathoms. One specimen. If inches long.

Mid Atlantic, Station 107 ; depth, 1 500 fathoms. Two specimens, f and 1^ inches long.

South of Australia, Station 159 ; depth, 2150 fathoms. One specimen, 1^ inches long.

Kermadec Islands, Station 171 ; depth, 600 fathoms. Two specimens, 1^ and 2
inches long.

Philippine Islands, Station 214 ; depth, 500 fathoms. Six specimens, 1^ and 1
inch long.

North of New Guinea, Station 218; depth, 1075 fathoms. One specimen, 2 inches
long.

South of Yedo, Station 235 ; depth, 565 fathoms. One specimen, 2 inches long.

Polyipnus, n. gen.

This genus differs from Sternoptyx in having the body covered with large, very thin
and deciduous scales, and in lacking the anterior spinous dilatation of the dorsal fin.
Habitat. — Philippine Islands.

Polyipnus spinosus, n. sp.

D. 12. A. 15.

Occiput terminating in a pair of horizontal spines pointing backwards.

Habitat. — Between the Philippine Islands and Borneo, Station 200; depth, 250
fathoms. One specimen, 2^ inches long.

This fish differs from Sternoptyx in having the body of a more regular shape, there
being no deep indentation by which the tail is separated from the trunk. The form of
its outline is oval, its greatest depth being contained once and two-thirds in the total

1 Bull. Mils. Comp. Zool, vol. x., 1883, p. 220.

REPORT ON THE DEEP-SEA FISHES. 171

length, without caudal. The head is much higher than long, its length one-third of the
total ; eye large, two-fifths of the length of the head. Mouth vertical, snout extremely
short. Intermaxillary narrow, and, although it does not entirely form the margin of the
upper jaw, it reaches as far as the cleft of the mouth, when the gape is open to its fullest
extent. The maxillary is a broad lamelliform bone ; the lower two-fifths of its anterior
margin remain free from the intermaxillary, and show a very obscure and rudimentary
denticulation. The teeth in both jaws are minute, and appear to form anteriorly an
extremely narrow band, and laterally a single series; vomerine teeth present, and similar.

The upper part of the head is much compressed, narrow, hollow, and bordered on each
side by a serrated ridge. The two ridges slightly converge behind, and are continued as
a pair of humeral ridges, which terminate behind in a strong and acute spine. On the
side of the head the ridges of the prseoperculum are very distinct, the posterior and
inferior meeting at a right angle, and the angle being armed with a slender claw-like
spine, which points downwards. Also the lower margin of the mandible is finely serrated,
and terminates behind in a short and obtuse spine.

Nostrils in front of the upper part of the eye, separated by a very narrow bridge of
skin, the posterior being much wider than the anterior.

Branchiostegals five. The gill-membranes overlapping the isthmus free. GUI-rakers
rather numerous, closely set, long and slender ; pseudobranchise present.

The dorsal fin is preceded by a minute forked spine, and composed of eleven soft rays.
A w^ell-developed adipose fin, which is about half as long as the rayed dorsal, occupies the
middle of the space between dorsal and caudal. Anal fin with fourteen rays. Caudal fin
composed of some thirty-five rays, some of which occupy the upper and lower edges of the
tail. Pectoral inserted low down on the side, composed of about fourteen very slender
rays, and pointing forw-ards, not backwards. The lower edge of the abdomen is convex
and denticulated, the ventrals being inserted in front of the vent, close together, and in a
vertical position. None of the scales have been preserved, but to judge from the pouches,
which are distinctly visible, they must have been large, and numbering perhaps thirty-
two, in a series along the middle of the side.

The luminous organs have reached in this fish an extraordinary degree of development
as regards size and number : —

1. A series of six, pearl-coloured, oblong organs runs on each side of the isthmus to
the root of the pectoral fin.

2. A series of ten along each side of the ventral edge, from the humeral symphysis to

the ventral fin.

3. A series of five, which are rather irregularly arranged, occupies a position higher
up the side above the level of the pectoral.

4. Two isolated organs are placed still higher up the side of the trunk, but below the
middle line.

172 THE VOYAGE OF H.M.S. CHALLENGER.

5. A series of five on each side of the abdomen, somewhat above the lower profile.

6. A series of seventeen along each side of the lower profile of the tail ; these are
smaller than the preceding, and the series is slightly interrupted behind the anal fin.

7. The organs on the head are all placed in its lower half; a series of six occupies the
roots of the branchiostegals.

8. A very large one is placed above the lower rim of the prseoperculum.

9. A small one occupies the suboperculum where it joins the operculum.

10. Finally, two of the smallest are placed, one in front of, the other behind the eye.

Gonostoma, Rafin.*

As far as it is possible to make out the anatomical structure from a specimen of
Gonostoma denudatum which has been preserved in spirits for some time, the conditions
are the following : —

The oesophagus is continued into a very long, tapering csecal stomach, the pyloric
portion of which is surrounded by seven short pyloric appendages. The intestine is
narrow throughout, attached in its upper portion along the csecal sac of the stomach, and
continued in a straight line to the vent.

The air-bladder is not only present but of large size, extending from one end of the
abdomen to the other. Its dorsal wall, as well as its posterior extremity, is rather
thick, whilst the membrane on its ventral aspect is very thin. I am unable to find any
communication between it and the oesophagus. A narrow muscular band starts from
each side of its anterior third, and is attached to the intermuscular ligaments of the fore
part of the trunk. The posterior end of the bladder is obtusely rounded, and has a
conical, muscular body attached to its ventral side. This muscular body is hollow in its
interior, and seems to communicate with the cavity of the bladder; the broad end of the
cone rests upon the coalescent mass of the kidneys, and is suspended by a tendinous
ligament from the vertebral column.

Ovaries large, elongate, lamellated; ova minute.

Gonostoma denudatum, Raf.

D. 14-15. A. 30-31. P. 11-12. V. 8. L. lat. 36.

The height of the body is contained five and a half times in the total length (without
caudal), the length of the head four times. Jaws heterodont, the intermaxillary being

' A fish, mentioned under the name of Sigmops stigmaticiis (Proc. U.S. Nat. Mas., 1884, p. 256), is not recognisable
from the notes accompanying this binomial term.

A fish, mentioned and rudely figured in La Nature, 1884, p. 184, under tlie name of Neostoma bathyphillum
[1 bathyphilum], L. Vaill., from a depth of 2220 metres in the Eastern Atlantic, seems to belong to Goiwstoma.

REPOKT ON THE DEEP-SEA FISHES, 173

armed with two, the maxillary with about twelve large distant teeth, the spaces between
them being filled with very small teeth ; lower jaw similarly armed with ten or eleven
large teeth. The entire cheek is covered with the enormously enlarged infraorbital.

Common in the Mediterranean and neighbouring parts of the Atlantic, attaining a
length of 7 inches ; evidently a species which comes to the surface at night.

Gonostoma elongatum (PL XLV. fig. B).

Gonostoma elongatum, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 187.

B. 11. D. 13. A. 29. P. 11. V. 7.

The cheek is not entirely covered by the infraorbital. Dentition as in Gonostoma
denudatuni. The height of the body is one-seventh of the total length (without caudal),
the length of the head two-ninths.

Habitat. — Indian Ocean, south of New Guinea, Station 191 ; depth, 800 fathoms.
One specimen, 6| inches long.

Ofi" Banda, Station 194a ; depth, 360 fathoms. One specimen, 4| inches long.

The height of the body is one-seventh of the total length, without caudal, the length
of the head two-ninths. Vent midway between the root of the caudal fin and the eye.
Eye rather small, two-thirds of the length of the snout, about one-eighth of the length of
the head, and narrower than the width of the interorbital space. Cleft of the mouth
exceedingly wide, the maxillary extending to the posterior angle of the prseoperculum ;
it is armed with about twelve large distant teeth, the interspaces being filled with small
teeth, the intermaxillary with two, and the mandible with about ten large teeth. The
infraorbital bone is dilated into a large very thin lamella, which extends backwards along
the upper margin of the maxillary, but covers only about one-half of the cheek. Opercular
bones very thin, like the rest of the bones of the head.

The whole of the gill apparatus reminds one very much of that of an anchovy. The
gill-laminae are very short, the gill-rakers long and needle-shaped. Branchiostegals
eleven, very short.

The dorsal fin commences a little behind the vertical from the vent, and is higher
than the body underneath. Of the anal fin the anterior portion is much higher than the
middle and posterior ; it terminates at a short distance in front of the caudal. Caudal
fin forked. Pectoral narrow, low down on the side of the body, composed of eleven rays,
two-thirds as long as the head. Ventral fins nearly twice as distant from the pectorals
as from the vent, which they do not reach.

Nothing can be said about the scales, as not only they are lost (if they were present),
but also the greater part of the skin. There are traces of scale pouches on the tail of the

174 THE VOYAGE OF H.M.S. CHALLENGER.

larger specimen, but it would appear as if the greater part of the trunk had been
scaleless. At any rate, no trace of the existence of scales is visible on such parts of the
trunk of the smaller specimen as have the skin preserved. The coloration was uniform
black.

The luminous organs are apparently less developed than in Gonostoma denudatum, but
their arrangement is essentially the same. Two rows run near to the lower edge of the
abdomen ; the lowermost series containing four in front of the pectoral, ten between
pectoral and ventral, four between ventral and vent, and twenty-two between the vent
and caudal fin. The upper abdominal series is composed of twelve organs, but does not
extend to the tail. A short series of oblong glandular masses occupies the root of the
upper and lower rudimentary caudal rays. Another similar mass is imbedded behind the
upper portion of the maxillary bone. A luminous organ also occupies the root of each of
the branchiostegals, as in Gonostoma denudatum, but none of the opercular organs are
preserved, if they were present at all.

Gonostoma gracile (PL XLV. fig. C).

Gonostoma gradle, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 187.

D. 10. A. 26. P. 11. V. 6.

Apparently scaleless. The cheek is not entirely covered by the infraorbital. The
larger teeth in the upper jaw rather numerous. The height of the body is one-ninth of
the total length, the length of the head one-fifth. Tail very slender and narrow.
Adipose fin absent.

Habitat. — South of Japan, Station 232 ; depth 345 fathoms. One specimen, 4f inches
long.

South of Japan, Station 230 ; depth 2425 fathoms. One specimen, 2^ inches long.

The height of the body is one-ninth of the total length, without caudal, the length of
the head one- fifth. Vent midway between the root of the caudal and the end of the
snout. Eye rather small, two-thirds of the length of the snout, about one-seventh of the
length of the head, and but little narrower than the width of the interorbital sjjace.
Cleft of the mouth exceedingly wide, the maxillary extending to the posterior angle of the
pra^operculum ; lower jaw very prominent in front. The maxillary is armed with about
thirteen larger teeth, which are not very remote from each other, the interspaces being
occupied with small teeth. Intermaxillary with two or three, mandible with about eleven
larger teeth, the latter being much smaller than those of the upper jaw. The infraorbital
bone is dilated into a very thin lamella, which extends backwards along the upper half of
the maxillary, and leaves the greater portion of the cheek uncovered. Gill ajjparatus as
in Goyiostoma elongatum ; branchiostegals ten.

REPORT ON THE DEEP-SEA FISHES. 175

The dorsal fin commences at some distance behind the origin of the anal and is
higher than the body underneath. Form of the anal fin as in Gonostoma elongatum;
it terminates at some distance from the caudal, the caudal peduncle being long and
slender. Caudal fin forked. Pectoral very narrow, nearly one-half as long as the head.
Ventral fins likewise very narrow, they reach to the vent, and their distance from the
latter is only two-fifths of that from the root of the pectorals.

This fish is evidently scaleless, and uniform deep black ; the fins transparent.

The luminous organs are still less developed than in Gonostoma elongatum, but their
arrangement is essentially the same. Two rows run near to the lower edge of the
abdomen ; the lowermost series containing four very small ones in front of the pectoral,
five between the pectoral and ventral, three between the ventral and anal, and very-
small ones, whose number cannot be made out, along the base of the anal fin. The upper
abdominal series is represented only by a single organ at about the middle of the trunk.
The majority of the organs on the trunk consist of two parts, namely, a larger, circular,
glandular disk and a superimposed small eye-like spot, with a black margin and white
pupil. An oblong glandular mass occupies the lower margin of the tail on each side of
the root of the rudimentary caudal rays, but is absent, or present in a radimentary con-
dition only, on the corresponding part of the upper side of the tail. Another similar
mass is embedded behind the upper portion of the maxillary bone, and is likewise
accompanied by an eye-like spot above. A small organ occupies the middle of the hind
margin of the prseoperculum. The organs which occupy the roots of each of the
branchiostegals are small and eye-like, and similar minute structures are scattered
in an irregular fashion along the middle, and also on the sides, of the abdomen.

Gonostoma microdon.

Gonostoma microdon, Giinth., Ann. and Mag. Nat. Hist., 1878, voL ii. p. 188.
Cydothone lusca, Goode and Bean, Bull. Mus. Comp. Zool., vol. x., 1883, p. 221.

D. 13. A. 18-21. P. 9. V. 7. L. lat. 26 (?).

Cheek naked. Teeth in the upper jaw very fine and numerous, with some larger ones
placed at regular intervals. Eye small.

Habitat— kt\a.-nt\c and Pacific (500 to 2900 fathoms).

North-east of Bermuda, Station 60 ; depth, 2575 fathoms. Eight specimens, 1 to 2\
inches long.

North-east of Bermuda, Station 61 ; depth, 2850 fathoms. Three specimens, 1} inches
long.

North-west of Bermuda, Station 40 ; depth, 2675 fathoms. Two specimens, 1| inches
long.

176 THE VOYAGE OF H.M.S. CHALLENGER.

South of Sombrero Island, Station 23 ; depth, 450 fathoms. Seven specimens, 1 to
li^ inches long.

South of Sombrero Island, Station 101 ; depth, 2500 fathoms. Two specimens,
1^ inches long.

Mid Atlantic, Station 106 ; depth, 1850 fathoms. Two specimens, 1 to 1^ inches long.
Off Pernambuco, Station 120; depth, 675 fathoms. Twenty-five specimens, 1^ to
2^ inches long.

South Atlantic, Station 137 ; depth, 2550 fathoms. One specimen, 1^ inches long.
South Atlantic, Station 337 ; depth, 1240 fathoms. One specimen, 2^ inches long.
South Pacific, Station 286 ; depth, 2335 fathoms. One specimen, 3 inches long.
The Kermadec Islands, Station 171; depth, 600 fathoms. One specimen, 2 inches
long.

The Kermadec Islands, Station 170; depth, 520 fathoms. Two specimens, 2 inches
long.

Mid-Pacific, Station 169 ; depth, 700 fathoms. Five specimens, 2 to 2^ inches long.
Mid-Pacific, Station 265 ; depth, 2900 fathoms. One specimen, 2 inch long.
Ofi"New South Wales, June 13, 1874. One specimen, 1-^ inches long.
South of Australia, Station 158 ; depth, 1800 fathoms. Two specimens, 2|- inches long.
Antarctic Ocean, Station 156 ; depth, 1975 ftithoms. One specimen, 2^ inches long.
North of New Guinea, Station 218 ; depth, 1070 fathoms. One specimen, 1^ inches
long.

North of New Guinea, Station 220 ; depth, 1100 fathoms. One specimen, 2|- inches
long.

North of New Guinea, Station 223 ; depth, 2325 fathoms. Two specimens, 2^ inches
long.

Off Amboina, Station 196 ; depth, 825 fothoms. One specimen, 2 inches long.
West Pacific, Station 226 ; depth, 2300 fathoms. One specimen, 2f inches long.
South of Japan, Station 230 ; depth, 2425 fathoms. One specimen, 1^ inches long.
South of Yedo, Station 237 ; depth, 1875 fathoms. Eight specimens, 1^ to 2^ inches
long.

Coast of Japan, June 1875. Two specimens, 1^ to 2J inches long.

Unfortunately all the specimens of this species are in a more or less injured condition ;
it is quite evident they were dragged for some considerable distance through the water,
and it is therefore very probable that the majority of them were actually obtained at
the depths indicated by the soundings.

The height of the body is contained eight and a half times in the total length, with-
out caudal, the length of the head five times. Vent nearly midway between the root of
the caudal and the end of the snout. Eye very small ; cleft of the mouth exceedingly

REPORT ON THE DEEP-SEA FISHES. 177

vvide, the maxillary extending to the posterior end of the praeoperculum ; lower jaw very
prominent in front. The maxillary is armed with a single series of numerous teeth which
gradually increase in size towards its posterior extremity ; in the posterior half of the
bone some of the teeth (placed at regular intervals) are larger than the others, but the
difference between them is much less than in the other species of this genus. Inter-
maxillary with one or two larger and several small teeth. Mandibulary teeth extremely
numerous and closely set, decreasing in size towards the front ; but near to the
symphysis the bone is armed with a single long fang which appears to be easily lost,
as it is present only in a few of the specimens ; infraorbital bone not dilated, leaving the
whole of the cheek uncovered. Branchiostegals nine. ,

The dorsal fin commences opposite to the origin of the anal, and is as high as the
body underneath. Form of the anal as in the other species ; it terminates at a short
distance from the caudal, the caudal peduncle being not much longer than deep. Caudal
fin forked. Pectoral fin extremely narrow ; ventral fin extending beyond the vent.

Some of the specimens are still provided with very large and deciduous scales, there
being only about five in a vertical series between the origins of the dorsal and anal fins.
But in the majority of the specimens the skin is quite scaleless, and does not show even
traces of pouches. The colour of all the specimens is black.

Luminous organs are present as very small eye-like spots ; they are arranged in two
series along each side of the abdomen, and in a single series along each side of the tail.
The branchiostegal series is likewise present, as well as an organ below the small eye,
but the glandular mass on the back of the tail is only rudimentary.

Photichthys.

Phosiehthys, Hutton, Cat. New Zeal. Fish., p. 55.

This genus is closely allied to Gonostoma, from which it differs in the following
points : —

Both jaws are armed with a single series of teeth ; those of the maxillary being
small and equal in size. The intermaxillary is armed w4th two large fangs besides the
small teeth ; mandible with seven large equidistant teeth, the spaces between them
being filled up with very small denticles. Vomer with a fang on each side of its head ;
palatine with strong, curved teeth, which gradually decrease in size backwards. The
dorsal fin corresponds in position to the space between ventrals and anal ; adipose fin
small. Air-bladder present as a long simple sac with thick walls.

As the specimens available are very much deteriorated, it appeared rather hazardous
to enter upon the examination of some points of their anatomical structure. On the
whole, it resembles much that of Gonostoma. The stomach is csecal ; when empty, its

(ZOOL. CHALL. EXP. PART LVII. 1887.) I'll 23

178 THE VOYAGE OF H.M.S. CHALLENGER.

walls appear thick and the mucous membrane laid into deep folds. Pyloric appendages
present, short, and in small number. Air-bladder long, thick-walled dorsally, but
thin and elastic along its ventral aspect. Towards the posterior extremity of the
bladder, which is subcylindrical and pointed, its wall is very thick, and of an almost
cartilaginous consistency behind ; its end is open, the circular aperture being thickened
and closed by what appears as a conical muscular mass, which, after it has penetrated
into the interior of the bladder, spreads out and forms a layer on the inside of its
posterior portion. An examination of fresh specimens will show the real condition of
this singular apparatus, the function of which is most likely connected with the com-
pression or expansion of the gas contained in the bladder.

Photichthys argenteus (PI. XLV. fig. A).

Phosichthys argenteus, Hutton, loc. cit., p. 56; and vol. v., pi. xv. fig. 90.

B. 21. D. 13. A. 26. P. 9. V. 7. L. lat. 50?

The height of the body is contained six and a half times in the total length, without
caudal, the length of the head four and a half times. The vent is nearly twice as distant
from the eye as from the root of the caudal. Eye of moderate size, one-fifth of the length
of the head, a little shorter than the snout, but as wide as the interorbital space. Cleft
of the mouth exceedingly wide, the maxillary extending to the posterior angle of the
pra3operculum ; lower jaw somewhat projecting beyond the upper. There is only one
infraorbital bone, but it is succeeded behind by two long and very thin supplementary
bones, which are attached along the upper margin of the maxillary. Cheek uncovered
either by scales or by bone.

The branchiostegals are very short, shorter than the eye. Four branchial arches,
which bear extremely short gill-laminse, much shorter than the opposite gill-rakers. On
the outer branchial arch there are eleven of these slender, needle-shaped, and distantly
placed gill-rakers in its lower portion, and five in its upper. Pseudobranchise absent.

The origin of the dorsal fin is somewhat nearer to the root of the caudal than to the
extremity of the snout, and the fin is nearer to the ventrals than to the anal. The
adipose fin is a very small and narrow lobe, which may be easily overlooked, or it may be
entirely absent. Anal fin much higher in front than behind, and terminating at some
distance from the caudal, the peduncle being long and deep. Caudal fin forked.
Pectorals narrow. Ventrals well developed, their root being equidistant from the vent
and the base of the pectorals ; they terminate at a long distance from the vent.

I am unable to state anything about the scales, as only the traces of some of the
scale-pouches on the tail have been preserved. The isthmus is deep and much com-
pressed, and the scales on each side are so arranged that one corresponds to and covers
each of the luminous organs of this region.

REPORT ON THE DEEP-SEA FISHES. 179

Not one of the specimens which I received from the Colonial Museum at Wellington
is in a tolerable state of preservation, so that I am not certain whether the following
list of luminous organs is exhaustive. There is one organ placed at the base of each
branchiostegal ray ; a series of seven larger ones runs along each side of the isthmus
and is continued as an abdominal series which consists of seventeen organs to the ventral
fin, and of as many from the ventral to the anal ; seventeen may also be counted along
the base of the anal to the caudal. As in Gonostoma a second series, situated higher up
the sides, accompanies this series on the trunk. A single luminous organ is situated in
front of the eye and covered by the prseorbital, and another under the transparent sub-
operculum. To judge from outward appearance, all these organs seem to possess the
same structure and to differ only in size.

This fish exceeds the allied forms in size, one of the specimens being 12 inches long.

According to Button, the specimens were found in Cook's Strait, thrown ashore
after severe gales.

Chauliodus, Bl. Schn.
Cliauliodus sloanii, Bl. Schn.

The following specimens of this well-known bathybial genus were obtained by the
Challenger. Previously it was known from the Mediterranean and Atlantic only.

HaUtat.—^ovAh. of New Guinea, Station 191 ; depth, 800 fathoms. One specimen,
8|^ inches long.

North of New Guinea, Station 216a ; depth, 2000 fathoms. One specimen, 2| inches

long.

South of Japan, Station 235; depth, 565 fathoms. One specimen, 5^ inches

long.

Mid-Atlantic, Station 104; depth, 2500 fathoms. One specimen, 7|- inches

long.

North-east of Bermuda, Station 60 ; depth, 2575 fathoms. One specimen, 3 inches

long.

Family Scopelid^.

Saunis, C. V.

Besides the species mentioned here, probably others descend to similarly moderate
depths, as, for instance, Saurus atlanticus, Saurus intermedius, &c.

180 THE VOYAGE OF H.M.S. CHALLENGER.

Saurus haianus.

Saurus kaianus, Giinth., Eeport on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 50, pL xxiii

fig. C.

Habitat. — Ki Islands, Station 192; depth, 140 fathoms. One specimen, 5|- inches
long.

Harpodon, Les.
Harpodon microchir (PI. XL VII. fig. A).

Harpodon microcliir, Giiath., Ann. and Mag. Nat. Hist., 1878, vol. i. p. 487.

B. 17. D. 14. A. 14. P. 12. V. 9.

Body elongate, compressed ; its greatest depth is below the origin of the dorsal fin,
and contained seven and a half times in the total length, without caudal. The caudal
peduncle is long and its least depth only one-third of that of the body. Vent situated
far backwards, its distance from the root of the caudal being only one-half of that from
the head. Head small, more compressed behind than anteriorly, the flat interorbital
space being one-fourth of the length of the head. The latter constitutes one-sixth of the
total length, without caudal. Snout very short, the diameter of the small eye being two-
fifths of its length and about one-eleventh of the length of the head. Bones of the head
thin and more or less flexible ; mandible extremely long, projecting in front, and nearly
three-fourths of the length of the head.

Cleft of the mouth extremely wide, armed with numerous slender, more or less curved
teeth of unequal size, all of which are movable and depressible towards the median line
of the mouth. The maxillary is armed with a narrow band, of which the inner series
contains the larger teeth ; mandible armed with a similar band, but the larger teeth are
nearly three times the size of those of the upper jaw, and terminate distinctly in
an arrow-head-shaped point. Palatine teeth irregularly biserial and extending far
backwards ; the anterior are the strongest and strongly curved. There is inside this
long band of teeth a second much shorter one. The hyoid bone and the concave margins
of all the branchial arches above and below are armed with clusters and bands of teeth,
and considering the great distensibility of the mouth, this fish must be able to seize and
to retain fishes of very considerable bulk.

The branchial apertures are exceedingly wide, the isthmus is narrow and compressed.
Gills four, pseudobranchise very distinct ; gill-laminse rather short.

The dorsal fin occupies a position midway between the eye and the root of the caudal
fin ; it is not quite so high as long, and rather lower than the body underneath. The
small adipose fin is a little nearer to the caudal than to the dorsal, and opposite to the
middle of the anal fin, which is of a similar shape to the dorsal but lower. Caudal fin

REPOET ON THE DEEP-SEA FISHES. 181

deeply emarginate. The pectoral fin is very small, about one-fourth of the length of the
head, and situated rather above the middle of the side. Ventral fins broad and generally
well developed, as long as the postorbital portion of the head, and inserted opposite to the
anterior dorsal rays.

The head and trunk are without scales, only one series of long lanceolate scales
follows the course of the lateral line. The tail is covered with small and extremely thin
cycloid scales, rather irregular in outline.

Sides silvery, back and fins blackish, buccal and branchial cavities black.

This species is known from a single specimen only, 27 inches long, and
obtained at Tokio, Japan. Although it is not known at what depth the fish was
obtained, it is evident from its organisation that it should be referred to the deep-sea
fauna.

Bathysaurus.

Bathysaurus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 181.

Shape of the body similar to that of Saurus, subcylindrical, elongate, covered with
small scales. Head depressed with the snout produced, flat above. Cleft of the mouth
very wide, with the lower jaw projecting ; intermaxillary very long, styliform, tapering,
not movable. Teeth in the jaws in broad bands, not covered by the lips, curved, unequal
in size and barbed at the end. A series of similar teeth runs along the whole length of
each side of the palate ; a few teeth on the tongue, and groups of small ones on the
hyoid. Eye of moderate size, lateral. Pectoral of moderate length. Ventral eight-
rayed, inserted immediately behind the pectoral. Dorsal fin in the middle of the length
of the body, with about eighteen rays. Adipose fin absent or present. Anal of moderate
length. Caudal emarginate. Gill-openings very wide, the gill-membranes being separate
from each other and from the isthmus. Eleven or twelve branchiostegals. Gill-laminse
well developed, separate ; gill-rakers tubercular ; pseudobranchise well developed.
Air-bladder absent.

Bathysaurus ferox (PI. XLVI. fig. A).

Bathysaurus ftrox, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 182.

D. 18. A. 11. P. 15. V. 8. L. lat. ca. 120.'

Adipose fin absent.

Habitat.— East coast of New Zealand. Station 1G8; depth, 1100 fathoms. One
specimen, 20 inches long.

1 This is the number of transverse series of scales ; the number of the large scales of the lateral line is only
about 74.

182 THE VOYAGE OF H.M.S. CHALLENGER.

The form of this fish is very elongate, depressed from the neck forwards, somewhat
cylindrical about the middle and rather compressed behind. The greatest depth of the
body, below the origin of the dorsal fin, is about twice the depth of the caudal peduncle,
and one-ninth of the total length, without caudal. The head is greatly depressed behind,
twice as broad as deep, its length being contained three times and three-fourths in
the total length, without caudal. Snout depressed and long, the hind margin of the eye
beino- in the middle of the length of the head ; eye rather large, one-seventh of the length
of the head, partly directed upwards, and separated from the intermaxillary by the
exceedingly narrow chain of infraorbital bones. The mouth is exceedingly wide, the
length of the mandible being nearly three-fourths of that of the head ; and the jaws are
powerful, especially the lower, which is greatly expanded on the lower aspect of the
head.

Teeth numerous, unequal in size, generally curved, and with a more or less distinctly
barbed point (see fig. A'"). Almost all are depressible in the longitudinal axis of the head.
In the upper jaw they form a broad band with the largest teeth along the inner margin
(fig. A'). The mandibulary band is still broader (fig. A") ; in fact, it consists of two
narrower bands between which the intermaxillary teeth are received. The vomerine and
palatine teeth form one continuous biserial row, close and parallel to the intermaxillary.
These teeth slightly exceed those of the jaws in size, at least anteriorly, but gradually
decrease in length backwards. The row consists of two series, those of the outer series
being shorter and fixed. Also the basibranchials are armed with small curved teeth,
uniserial in front and biserial behind. Patches of small teeth take the place of gill-
rakers.

The upper side of the head, the snout, and the branchiostegal membrane are naked,
the cheeks and the gill-cover scaly. The nostrils are a pair of small ojDenings, close
together, but separated by a short flap ; they are about midway between the eye and the
end of the snout, and quite at the upper side of the head. The muciferous channels are
narrow with small but distinct openings.

Branchiostegals long and flexible ; the gill-openings extremely wide, extending from
the upper end of the gill-cover near to the symphysis of the lower jaw; the left branchio-
stegal membrane overlaps the right in front.

The dorsal fin is higher anteriorly than posteriorly, and higher than the body
underneath, the length of the second ray being more than one-half of that of the head ;
this fin occupies the middle of the length of the fish, its distance from the root of
the caudal being equal to that from the end of the snout. The anal fin commences
shortly behind the vertical from the last dorsal ray, and is higher in front than behind.
Caudal fin emarginate, with a great part of its basal portion covered with scales.
Pectoral long, extending to the ninth dorsal ray ; its base is narrow, and when in
use this fin assumes a horizontal position much like the ventral. Ventral fin

REPORT ON THE DEEP-SEA FISHES. 183

strong, broad, horizontal, as in bottom fish generally ; it is inserted so that its inner ray-
corresponds to the anterior dorsal ray.

Scales rather small and cj^cloid ; there are about ten series between the origin of the
dorsal fin and the lateral line, and about eight between the lateral line and the anal.
The lateral line is broad and very distinctly marked ; its scales correspond only to about
every second transverse series ; they have their hind margin raised and free, and two
small but distinct pores open above and below each scale.

Colour brownish, lower parts of the head and abdomen black ; buccal and branchial
cavities black. A stripe between each pair of dorsal rays ; the membrane between the
three middle caudal rays, the anal fin, the outer (respectively lower) sides of the pectoral
and ventral fins blackish.

The oesophagus passes into a long and wide csecal sac, which, however, does not reach
backwards to the middle of the length of the abdominal cavity. The pylorus is on the
same level as the cardiac end of the stomach ; two short and wide pyloric appendages
are placed opposite to each other. The intestine runs straight backwards without any
lateral bend, and is separated from the short rectum by a circular fold, the course of which
is also visible externally. The mucous membrane of the intestine is densely and deeply
folded, the folds being raised in a reticulated fashion. The liver consists of a right and a
left lobe, connected by a thin transverse bridge. The left lobe is broad and flat,
extending somewhat further backwards than the stomach. The right lobe is far more
bulky, extending nearly to the end of the abdominal cavity, and hollowed out on one side
for the reception of the intestinal tract. This lobe is connected with the transverse
portion of the liver by a long and thin strip of the substance of the liver. Gall-bladder
of moderate size. Air-bladder absent.

The ovaries are closed cylindrical sacs, and attached to each other along their whole
length ; they did not contain ova.

Bathysaurus agassizii, Goode and Bean,^ described from a specimen 21 inches long,
and obtained at a depth of 647 fathoms in the Atlantic, lat. 33° 35' N., long. 76° 0' W.,
is probably not specifically distinct from the Pacific specimen. It seems to be a fish with
a somewhat deeper body, but, then, it was ascertained to be a " female, full of nearly
mature eggs."

Bathysaurus mollis (PI. XLVI. figs. B, B').

Bathysaurus mollis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 182.
D. 15. A. 11. P. 15. V. 8.
Adipose fin present. Rays of the fins, especially the front rays of the dorsal, rather
elongate.

" Bull Mus. Comp. Zo6L, vol. x., 1883, p. 215.

184 THE VOYAGE OF H.M.S. CHALLENGEE.

Habitat. — Off Yedo, Station 237; depth, 1875 fathoms. One specimen, 19 inches
long.

Middle of South Pacific, Station 281 ; depth, 2385 fathoms. One specimen, 7^
inches long.

This fish is highly interesting, inasmuch as the points in which it difi'ers from
Bathysaurus ferox indicate that it is merely an abyssal modification of that species ; or,
if the present form were not known to attain to nearly the same size as Bathysaurus
ferox, it might have been taken for an earlier stage of the development of the latter.

The fish is of a whitish colour, the buccal and branchial cavities and the lower parts
of the body being black. The bones of the head are less firm than in Bathysaurus ferox,
the scales extremely thin and deciduous (only a few are preserved), some parts of the
body, as the gill-cover and the prseventral portion of the body, being naked. All the
fin rays are prolonged, and a short but high adipose fin is present, as also a broad fold at
the root of the caudal fin above as well as below. The greatest depth of the body is
below the origin of the dorsal fin and more than twice the depth of the caudal peduncle,
one-ninth of the total length, without caudal. The head is less broad than in Bathy-
saurus ferox, about one-third broader than deep, and its length is two-ninths of the
total, without caudal. Snout depressed and of moderate length ; eye of moderate size,
one-half of the length of the snout, one-seventh of that of the head, and two-thirds of the
width of the interorbital space.

Otherwise the configuration of the head as well as the dentition are as in Bathysaurus
ferox. The position of the nostrils is likewise similar, but they are separated by a rather
long and pointed tentacle, and there is another aperture in front of the nostrils which
leads into one of the superficial mucous channels.

The anterior dorsal rays are much higher than the body underneath, their length
being equal to that of the head without snout ; but the position of the finis the same as
in Bathysaurus ferox. The adipose fin occupies a position behind the last anal ray; the
caudal fin is very broad, deeply emarginate, and without scales on its base. Pectoral
with a very narrow base, lateral, subhorizontal, with the middle ray longest, nearly as
long as the head. Ventral fin very strong and broad, and with the outer ray enveloped in
thick skin ; it is inserted in front of the dorsal and is not much shorter than the pectoral.

In the young specimen the body and tail are ornamented with fourteen narrow
vertical bars, composed of minute pigment spots, and reaching across the whole depth of
the body. In the interspaces between them there is a shorter bar which does not extend
upwards beyond the lateral line. A pattern of coloration of this kind is of extremely
rare occurence in deep-sea fishes.

The structure of the lateral line is the same as in Bathysaurus ferox.

This species difi'ers internally from its congener more than one might expect in two

EEPORT ON THE DEEP-SEA FISHES. 185

species wlaicli are so closely allied. Tlie stomach has the same form, but the pylorus is
furnished with one appendage only, and the intestine makes in its lower course four
bends, two to the right and two to the left. The network of the mucous membrane is
less close and the folds are lower. The liver consists only of the left lobe and the
transverse bridge, but the bulky right lobe, which in Bathysaurus ferox forms the
greater part of the liver, is entirely absent in this species. The specimen described is a
male possessing a narrow tape-like testicle on eacli side of the posterior half of the
abdominal cavity.

Bathy])terois.

Batlujpferoig, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 183.

Shape of the body like that of an Aulopus. Head of moderate size, depressed in front,
with the snout projecting, the large mandible very prominent beyond the upper jaw.
Cleft of the mouth wide ; maxillary much developed, very movable, much dilated behind.
Teeth in narrow villiform bands in the jaws. On each side of the broad vomer a small
patch of similar teeth ; none on the palatines or on the tongue. Eye very small. Scales
cycloid, adherent, of moderate size. Eaj-s of the pectoral fin much elongated; some of
the upper being separate from the rest and forming a distinct division. Ventral fins
abdominal, with the outer rays prolonged, eight-rayed. Dorsal fin inserted in the middle
of the body, above or immediately behind the root of the ventral, of moderate length.
Adipose fin present or absent. Anal short. Caudal forked. Gill-openings very wide ; gill-
laminse well developed, separate from each other ; gill -rakers long. Pseudobranchise absent.

Mr. Murray^ observes about these fishes {Bathypterois longipes): — "When taken
from the trawl they were always dead, and the long pectoral rays were erected like an
arch over the head, requiring considerable pressure to make them lie along the side of
the body; when erected they resembled Pennatulids like Umhellula." If we had any
evidence of some deep-sea fish feeding on Pennatulids, we might suppose that the function
of those rays consisted in attracting other fishes. But in the absence of such evidence,
I am inclined to regard them as organs of touch.

Bathypterois longifilis (PI. XLVII. fig. B ; PL XL VIII. fig. B).

Batlnjptcrois lonnifilis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 183.
B. 12. D. 13. A. 9. P. 3 I 13. V. 8. L. lat. 61. L. transv. 6 j 10.

The uppermost pectoral ray is the strongest, longer than the whole fish, bifid towards
its extremity. Outer ventral rays with dilated extremities. Dorsal fin inserted imme-
diately behind the root of the ventrals. An adipose fin.

I Xarr. Chall. E.\p., vol. i. p. 218.

(ZOOL. CHALL, ESP.— P.\RT LVIL — 1S87.) ■'-''' -*

186 THE VOYAGE OF H.M.S. CHALLENGER.

Habitat. — Near the Kermadec Islands, Stations 170, 170a; depths, 520 and 630
fathoms. Two specimens, 13 inches long.

The form of the body of this singular type of fishes is somewhat elongate, moderately
compressed; its greatest depth is below the origin of the dorsal fin and equals one -sixth of
the total length, without caudal. The head is broad, composed of solid bones, about as deep
as wide, and terminates in a long, depressed, wedge-shaped snout. The eye is minute,
two-thirds as distant from the extremity of the snout as from the hind margin of the
gill-cover. Interorbital space very broad, osseous, convex, with a width equal to the
length of the snout.

The bones composing the jaws are very powerful and firm, thus compensating for the
weakness of the dentition, which consists merely of a narrow band of villiform asperities
in the jaws and of a similar patch on each side of the vomer. The intermaxillary alone
is toothed, styliform, tapering and closely fitting into the front margin of the maxillary ;
the latter is toothless, about half as long as the head, and its hinder portion, which extends
beyond the intermaxillary, is dilated into a broad and oblong lamella. When the mouth
is closed, the maxillary occupies a horizontal position in ab.out the middle of the depth
of the head, and extends beyond the middle of its length. The lower jaw is extremely
broad, its halves touching each other below, when the mouth is shut. Its symphyseal
portion forms a strong and large projection.

Branchial apertures very wide, extending forwards to the end of the isthmus, the gill-
cover remaining entirely free. There are four gills with well-developed gill-laminss.
All the branchial arches are provided with gill-rakers, but those of the outer arch are the
longest and those of the inner the shortest. The outer arch has thirty gill-rakers in its
low^er branch and twelve in its uj^per ; they are slender, needle-shaped, the longest about
one-fourth of the length of the head.

The dorsal fin occupies exactly the middle between the extremity of the upper jaw
and the root of the caudal fin ; it is much higher in front than behind, the anterior rays
being rather higher than the body underneath. Adipose fin narrow, nearly midway
between the dorsal and caudal. Anal fin opposite to the space between the dorsal and
adipose. Caudal fin emarginate. Pectoral fin lateral, placed in the middle of the
height of the trunk, and composed of exceedingly elongate and simple rays, which are
quite free, not connected by membrane; the longest reach to the end of the anal
fin. An exceedingly long and compressed ray is detached from the fin and articu-
lated at the upper end of the clavicle, opposite to the upper margin of the gill-cover.
It extends far beyond the caudal fin and is bifid in its posterior half; it is accompanied
below by two other rays, which are much shorter and connected by a membrane
with the long ray. By a separate set of muscles (PI. XLVIII. fig. B') it can be moved
outwards or upwards (c) so as to form nearly a right angle with the longitudinal axis of

REPORT ON THE DEEP-SEA FISHES. 187

the body, whilst another muscle (h) draws it downwards into a line with the other pectoral
rays.

The large ventrals are inserted immediately in front of the origin of the dorsal fin.
Its two outer rays are simple, the others broad and dichotomously split. The extremities
of the two outer ones and of the outer branches of the third are modified into soft, swollen,
long, lamelliform pads. These singular appendages extend backwards to the end of the
anal fin and remind us of similar structures in certain Cyprinodonts, in which the
appendages are sexual and peculiar to the male sex. Both the specimens of the present
species are females.

The scales are of moderate size, rather irregular in shape, and cycloid. The lateral
line runs along the middle of the side.

Colour light greenish with narrow black margins to the scales ; sides of the head, the
abdomen, and the buccal and abdominal cavities black. Vertical and ventral fins black,
with lighter margins; pectoral fins without colour.

The structure of the pectoral arch (PI. XLVIII. fig. B) shows some noteworthy
peculiarities. The clavicle (cl) consists of a narrow subvertical branch which is slightly
bent in the form of a knee ; the shorter part above the knee is connected with the skull
by two supraclavicles (scl', scl"), of which the upper is two-pronged as usual and partially
excavated into a muciferous tube. The portion below the knee is posteriorly dilated into
a broad, thin, and slightly convex lamella {cV). Although separated from the narrow
vertical part by a shallow groove, this lamella is in perfect continuity with the clavicle,
and, therefore, cannot be the coracoid bone, for which it might be taken.

The cartilaginous lamella which intervenes between the clavicle and the pectoral fin
is broad and thin with four comparatively small ossifications.

The lower ossification {co) represents the coracoid ; it is of an oval shape with a
notch in its upper margin. The scapula (sc) occupies the upper portion of the cartilage,
and surrounds the large vacuity which generally distinguishes this bone ; it bears the
long upper pectoral rays without any intervening basalia. A large space (c«) between
the three bones described remains cartilaginous ; but there are behind this cartilaginous
area two other fiat and thin bones {b', h") which may be taken either as basalia or as
detached portions of the coracoid and scapula. A vacuity is left between them, and
another between the lower and the coracoid. The lower pectoral rays are thus articulated
dii-ectly to the narrow cartilaginous border of the coracoid and some to the lower basale.

The stomach terminates behind in a very short caBcal sac, its pyloric portion being
much shorter and narrower than the cardiac. Its walls are rather thick, and its mucous
membrane is deeply folded longitudinally. Pyloric appendages are absent. The com-
mencement of the intestine has a much greater circumference than the pyloric portion of
the stomach, and its interior is densely beset with long villi. The succeeding part of the

188 THE VOYAGE OF H.M.S. CHALLENGER.

intestine is but slightly convoluted, possesses very thin walls, the mucous membrane
beino- without villi, but forming numerous circular, low, transverse folds. The liver is
small with a short lobe on the right side. Gall-bladder small, detached from the liver.
Air-bladder absent. Ovaries elongate closed sacs, without ova in our specimens.

Bathypterois longipes (PI. XLVIII. fig. A).

Bathypterois longipes, Glinth., Ann. and May. Nat. Hist., 1878, vol. ii. p. 184.
B. 12. D. 13. A. 10. P. 2 I 7-8. V. 8. L. lat. 55. L. transv. 6 | 8.

The uppertnost pectoral ray is the strongest, about as long as the whole fish, bifid
towards its extremity. Outer ventral rays much prolonged, strong, but not dilated at
the extremity. Dorsal fin inserted at some distance behind the root of the ventrals.
Adipose fin present or absent.

Habitat. — Ofi" the east coast of South America, Station 325 ; depth, 2650 fathoms.
Two specimens, 9 inches long.

This species is very similar to Bathypterois longijilis, from which it difi'ers only
in the following points. Eye minute. The dorsal fin is placed further backwards,
its origin being nearly midway between the end of the snout and the root of the
caudal ; consequently the root of the ventral is some distance in advance of the
dorsal, and the end of the dorsal is vertically opposite to the fifth anal ray. One
specimen possesses, the other lacks the adipose fin. Caudal fin deeply forked, with the
outer rays much produced. Of the two branches into which the posterior third of the
long pectoral ray is split, one is much shorter and weaker than the other. The two outer
ventral rays are closely adpressed from the root to the end, and much stouter and longer
than the other rays ; they are articulated to the end and without the soft pads described
in the preceding species. These fin rays extend beyond the end of the anal fin.

Colour black, with white fins.

Bathypterois longicauda (PI. XXVI. fig. B).

Bathypterois longicauda, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 184.
D. 12. A. 9. P. 2 I 9. Y. 8. L. lat. 55. L. transv. 6 | 8.

The uppermost pectoral ray is the strongest, longer than the whole fish, bifid from
the middle of its length. The outer ventral rays much prolonged, filiform. Dorsal fin
inserted at a considerable distance behind the root of the ventrals, and extending to
above the anal. Caudal deeply forked with the lobes prolonged. Adipose fin present.

HaUtat.—MiMla of Southern Pacific, Station 289, October 23, 1875 ; depth, 2550
fathoms. One specimen, 3 inches long.

REPORT ON THE DEEP-SEA FISHES. 189

This fisli represents the youBg condition of Bathypterois ; possibly it may be merely
the young of Bathyiiterois lomjipes, but this, of course, is at present subject to doubt, as
that species has hitherto been found in the Atlantic only. The body of the only
specimen available is much twisted and would seem to be much narrower than the head,
but it is impossible to say how much of this is due to contraction caused by the
preserving fluid. The position of the fins is as in Bathypterois longipies, but all the
fin rays are much more elongate. The distance between the dorsal fin and the occiput
is scarcely equal to the length of the head. This fin as well as the anal are very high.
Adipose fin present. Caudal broad and deeply cleft. The long upper pectoral ray is
cleft, less than one-half of its length being simple, and one branch being much shorter
than the other. The longest of the lower pectoral rays reaches nearly to the caudal fin,
and the two outer ventral rays extend still further back, being more than twice as long
as the longest l^ranched ray.

Sides of the head and the lower part of the abdomen black ; tail and fins transparent.

Bathypterois quadrifilis (PL XXXIII. fig. B).

Bathypterois quadrifilis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 184.
B. 12. D. 14. A. 9. P. 2 I 9. V. 9. L. lat. 59. L. tiansv. 6 | 8.

The uppermost and lowermost of the pectoral rays are filiform, the former bifid for
more than two-thirds of its length, the latter simple. Outer ventral rays much prolonged,
strong, not dilated at the extremity. Dorsal fin inserted close behind the root of the
ventrals. Adipose fin present.

Habitat. — Ofi" the coast of Brazil, Station 126 ; depth, 770 fathoms. Two specimens,
8 1 inches long.

Ofi" the coast of Brazil, Station 121 ; depth, 500 fathoms. One specimen, 5^ inches
long.

This species difi'ers somewhat more from the preceding than these do among
themselves. The greatest depth of the body is one-seventh of the total length, without
caudal, the length of the head nearly one-fifth. The head is remarkably flat above, and
the mdth of the interorbital space exceeds the length of the snout. The eye is small,
l)ut larger than in the two preceding species, about one-third of the length of the snout,
and one-fifth or one- sixth of the length of the postorbital portion of the head.

The dentition and branchial apparatus do not ofi'er any noteworthy peculiarity.

The dorsal fin occupies the middle between the extremity of the upper jaw and the
root of the caudal fin. A narrow adipose fin is present and midway between the dorsal
and caudal. The anal fin commences immediately behind the dorsal, its origin being
equidistant from the roots of the pectoral and caudal. Caudal fin emarginate.

190 THE VOYAGE OF H.M.S. CHALLENGER.

The priucipal distinctive feature of tliis species is that it possesses not only the long
detached upper pectoral ray, but also an equally long lower ray, which, however, is not
removed from the remainder of the fin. The upper ray becomes bifid in its proximate
third, and is accompanied by an extremely short rudimentary second ray ; it scarcely
reaches to the caudal fin and is shorter than the lowermost ray, ^^•hich may reach to the
end of the caudal and is split only at its very extremity.

The structure of the ventral fins is the same as in Bathypterois longipes, but the
strong outer rays are somewhat curved and do not reach the end of the anal.

The scales are cycloid as in the other species, but those behind the basal portion of
the pectoral fin are deeply pectinated, provided with from five to ten long and narrow
teeth, of which the middle ones are the longest (see figures).

Colour blackish or black ; pectoral filaments whitish.

Ipnops.

Ipnojis, Giintli., Ann. and Mag. Xat. Hist., 1878, vol. ii. p. 187.

Body elongate, subcylindrical, covered with large thin deciduous scales, and without
luminous organs. Head depressed, with broad, long, spatulate snout, the whole upper
surface of which is occupied by a pair of large transparent lamelliform membrane
bones which cover a luminous organ longitudinally divided into two symmetrical halves.
Eyes absent ; nostril reduced to a minute opening in front of each lamina. Bones of
the lower and lateral parts of the head well ossified. Mouth wide, with the lower jaw
projecting ; maxillary dilated behind. Both jaws with narrow bands of villiform teeth ;
palate toothless. Pectoral and ventral fins well developed, and, owing to the shortness
of the trunk, close together. Dorsal fin at a short distance behind the vent ; adipose fin
absent ; anal fin moderately long ; caudal subtruncated. Pseudobranchise absent ; air-
bladder absent ; pyloric appendages absent.

This genus is closely allied to Bathypterois, not only in its external characters, but
also in the structure of its abdominal organs. Professor Moseley has kindly acceded to
my request to make a histological examination of the remarkable organ on the upper
surface of the head. The results of his examination are given in Appendix A and
Pis. LXVIL, LXVIII.

Ever since the discovery of this fish much uncertainty has prevailed with regard to
the nature and function of the extraordinary apparatus on the upper side of the head ;
but from Professor Moseley's examination it seems to be almo.st beyond doubt, that it is a
special form of phosphorescent organ. The power of producing light, and thereby
attracting other creatures, must be of great use to a fish, which, deprived of organs of
sight and touch, would be unable to procure its food.

REPORT ON THE DEEP-SEA FISHES. 191

The question of the homology of the luminous organ and its covering lamellae is still
obscure ; and no other specimen can be sacrificed to investigate the osteology of the
skull. If, as Professor Moseley's investigations seem to prove, the luminous organ is not
a modification of the eye, as Mr Murray and myself supposed at first, and if the organ of
vision with the optic nerve has disappeared, the luminous organ is probably the
homologue of that vi^hich is found in some Scopelids between the eye and nostril, and the
covering plates would be the homologues of the prseorbital membrane bones. With the
abortion of the eyes the luminous organs with their prseorbitals would have moved from
their usual lateral position to the top of the head.

Ipnops murrayi (PI. XLIX. fig. B).

Ipno2)s murrayi, Giinth., Aim. aud Mag. Nat. Hist., 1878, vol. ii. p. 187.
B. 12. D. 10. A. 1.3. P. 14. V. 8. L. lat. .55.

Body elongate, cylindrical, tail compressed behind, head depressed. The depth of
the trunk diminishes but little backwards, and is contained thirteen and a half times
in the total length, without caudal ; the length of the head is one-sixth of the total.
Head broad, much broader than deep, its greatest depth being two-thirds of its length.
Snout broad, much dejiressed, with obtusely rounded anterior profile ; cleft of the mouth
very wide, the maxillary moderately dilated behind and extending beyond the middle
of the length of the head. Mandible projecting beyond the upper jaw, broad, but owing
to the depressed form of the snout its outer surface is nearly entirely at the lower side
of the snout. Infraorbital chain of bones very narrow, wedged in between the trans-
parent lamina and the maxillary, with four very distinct apertures leading into the
mucous duct. The upper surface of the head, including the snout, is wholly covered by
the two cornea-like laminaj of the luminous apparatus. They are closely attached to
each other along the median line, each being divided by a shallow transverse ridge into
a larger anterior and a smaller posterior portion. The ridge turus forward near and
parallel to, the median line, and marks the course of a superficial mucous duct.

The gill-laminae are well developed and the gill-rakers long, needle-shaped, closely
set, about twenty -two in number on the outer branchial arch.

The vent is nearly twice as distant from the root of the caudal fin as from the end
of the snout, and rather more than the length of the head from the gill-opening ; it is
placed between the ventral fins.

The dorsal fin commences immediately behind the vertical from the vent ; it is short,
but its longest rays are twice as high as the body. Origin of the anal midway between
the vent and the root of the caudal, composed of rays which are still more slender and
shorter than those of the dorsal. Caudal fin narrow, subtruncated, more than half as long
as the head. Pectorals rather feeble, lateral, as long as the caudal, and extending to the

192 THE VOYAGE OF H.M.S. CHALLENGER.

ventrals. Ventrals composed of stronger rays, horizontally placed and somewhat distant
from each other, as is frequently found in fishes habitually moving on the bottom ; they
slightly exceed the pectorals in length.

The scales are large, thin, deciduous, forming only six longitudinal series on each side
of the trunk. Lateral line faintly indicated along the middle of the body ; the
muciferous channels on the head are also narrow, with small apertures.

Brown, with colourless fins. Buccal and branchial cavities and the lower side of the
head black.

Habitat. — South Atlantic and Indian Ocean.

Coast of Brazil, Station 124; depth, 1600 fathoms. One specimen, 4^ inches long.

Near Tristan da Cunha, Station 133 ; depth, 1900 fathoms. Two specimens, 5\ inches
long.

North of Celebes, Station 198 ; depth, 2150 fathoms. One specimen, 4 inches long.

Chloroplithalmus, Bonap.

Eyphalonedrus, Goode, Proc. U.S. Nat Mus., 1881, p. 483.

The only point in which Dr. Goode's diagnosis apparently difiers from that given by me
in Fish., vol. v. p. 403, is that he denies the presence of lingual teeth. However, these
teeth are so minute in Chlorophthalmus agassizii as to require a magnifying glass to find
them, and therefore may easily be overlooked. But even if a species without these
rudimentary structures should be found, their absence could not justify a generic separa-
tion. The sheaths in which the scales are lodged show, especially after the loss of
the scales, a very conspicuous arrangement of straight parallel oblique lines, very
characteristic of the two first species of this genus. The following species are known
at present.

Chlorophthalmus agassizii (PL L. fig. C).

Chloroplithalmus agassizii, Bonap., Faun. it. Pesc. c. fig.
„ „ Giinth., Fish., vol. v. p. 404.

Hyphalonedrus chalybeius, Gooile, lor,. ciL, p. 484; and BuU. Mus. Comp. Zocil., vol. x., 1883,

p. 223.

B. 10. D. 11-12. A. 9. P. 16-18. V. 9. L. lat. 52-53. L. trans. 7 | 6.^

The length of the head is contained thrice and three-fourths in the total (without
caudal); eye scarcely more than one-third of the length of the head, a little longer
than the snout, which is moderately produced, and equal to the postorbital por-

* Not 4 I 6 as stated by me in Fish., vol. v. p. 404.

REPOET ON THE DEEP-SEA FISHES. 193

tion of the head. Body with large brownish blotches which are subquincuncially
disposed.

Gill-laminse rather shorter than the longest gill-rakers, which are very slender, needle-
shaped, and 5 -f- 18 in number. Pseudobranchise large.

Attains a length of about 4 inches. Not rare in the Mediterranean, it has been
more recently found by the U.S. Fish Commission off the coast of Ehode Island, and
southward to about lat. 38° 30' N., in 120 and 156 fathoms.

Chlorophthalmus i^roductus, n. sp. (PI. L, fig. D).

Closely allied to Chlorophthalmus agassizii, but with longer snout, and more numerous
scales.

B. 8. D. 11. A. 10. P. 16. V. 9. L. lat. 58. L. trans. 8 | 9.

The length of the head is contained thrice and one-third or thrice and one-fourth
in the total (without caudal) ; eye a little more than one-third of the length of the head,
slightly exceeding the snout in length, and equal to the postorbital portion of the head.
Snout produced. Coloration uniform.

Lingual teeth minute and few in numbei*. Gill-laminse rather short, shorter than
the slender gill-rakers, of which there are 2-1-15; the longest gill-rakers about one-third
as long as the eye. Pseudobranchise large.

Habitat. — Off Matuku, Fiji Islands, Station 173; depth, 315 fathoms. Two
specimens, 3 and 5 inches long.

Chlorophthalmus nigiipinnis (PI. LI. fig. A).

■ CMorophfhalrmis nigripinnis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol iL p. 182.
B. 7. D. 11. A. 9. P. 16. V. 9. L. lat. 50. L. transv. 4^ | 5.

Similar to Chlorophthalmus agassizii. The length of the head is contained thrice
and three-fourths in the total length (without caudal) ; the eye is large, two-fifths of the
length of the head and three times the width of the interorbital space. The distance of
the adipose fin from the dorsal equals that between the latter and the front margin of
the eye. Teeth in the jaws, on the vomer and palatine bones, in very narrow bands.
Pectoral rather shorter than the ventral, which extends far beyond the vent ; the vent
being much nearer to the ventral than to the anal. Silvery, with some very indistinct
darker spots on the side of the body ; top of the dorsal and extremity of each caudal lobe
deep black.

Habitat.— OS Tv^'oMd Bay; depth, 120 fathoms. Two specimens, 5 J and 6 inches

long.

(ZOOL. CHALL. EXP. — PART LVII. — 1887.) LU 25

194 THE VOYAGE OF H.M.S. CHALLENGER.

The snout is less produced and depressed than in Chlorophthahnus agassizii ; the jaws
are generally weaker and the maxillary extends beyond the anterior margin of the eye.

Four gills, with pseudobranchise. The gill-rakers of the anterior arch are slender, the
longest not quite as long as the half of the eye, twenty-five in number, of which the five
uppermost are quite rudimentary.

Peduncle of the tail not compressed, nearly as broad as high ; the dorsal region of the
trunk and tail is also broad. Scales thin and cycloid, with very minute concentric
striae and lacerated posterior margins.

The terminal portion of the three outer ventral rays is thickened and covered with a thick
mucous layer, a peculiarity which we shall find still more developed in the following species.

The dorsal fin is high, the anterior rays being much higher than the body underneath,
and more than twice as long as the anterior anal rays.

Uniformly silvery, with the top of the dorsal fin and the extremity of the caudal lobes
black ; the mouth and gill-cavity are not coloured.

This fish shows nothing to indicate its bathybial life beyond the excessively large
eye ; and it is not likely that it descends to any more considerable depth than that
from which it was obtained.

Chlorophthalmus gracilis, (PI. XLIX. fig. A).

Chlorophthalmus gracilis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 182.
B. 10. D. 11. A. 11. P. 22. V. 8. L. lat. 60. L. transv. 6 | 7.

The length of the head is one-fourth of the total length, without caudal. The tail
being slender, the distance between the end of the anal and root of the caudal is not
very much less than the length of the head. Distance of the adipose fin from the dorsal
equal to that between the latter and the front margin of the eye. Snout depressed,
flat, with the lower jaw prominent. Interorbital space rather broad, more than the
vertical diameter of the eye. Eye large, its horizontal diameter being two-ninths of the
length of the head, and two-thirds of that of the snout. Teeth in the jaws in coarsely
villiform bands, those on the vomer and palatine bones in a single series ; the vomerine
series being interrupted in the middle. Only a few minute teeth on the tongue. The
intermaxillary is toothed along the whole of its length, and extends nearly as far back as
the maxillary, the extremity of which reaches to behind the eye. Pectoral considerably
longer than the ventral, which does not extend to the vent, the vent being a little nearer
to the anal than to the ventral. Origin of the dorsal fin immediately behind the root of
the ventral. Scales cycloid ; those of the lateral line and between the ventral fins larger
than the rest. Uniformly brownish-black ; fins of a lighter colour.

Habitat. — Off" the eastern coast of New Zealand, Station 168; depth, 1100 fathoms.
One specimen, 8 inches long.

REPORT ON THE DEEP-SEA FISHES. 195

Middle of South Atlantic, Station 300; depth, 1375 fathoms. Three specimens, 9^
inches long.

Off Juan Fernandez, Station 335 ; depth, 1425 fathoms. One specimen, 4 inches long.

The body is but slightly compressed in the middle, gradually passing into the head
which is depressed, and into the more compressed caudal peduncle. The greatest
depth is below the origin of the dorsal fin, about one-half of the length of the
head, and contained seven and a half times in the total length, without caudal.
Snout depressed, broad, with the lower jaw projecting. Mandible dilated on its ventral
aspect and much longer than one-half of the length of the head ; bones of the head
generally rather thin, leaving wide round vacuities in the course of the muciferous
channels, which are well developed.

The gill-rakers of the first branchial arch are needle-shaped, closely set, the longest
being as long as the eye.

Dorsal fin much higher than the body underneath, its anterior rays being much
longer than those of the anal fin. Caudal fin emarginate, with the upper lobe rather
longer than the lower. Pectoral fin elongate, with a rounded posterior margin, shorter
than the head, but extending beyond the dorsal fin. The ventral fins are horizontal,
rather broad, and show sometimes a modification of the distal half of the three or four
outer rays. This is seen only in the two larger specimens from Station 300, ])ut not in
the one from Station 168 or in the young specimen. The degree to which these rays
are thickened is not the same in the two specimens which show this peculiarity ; in one,
which is slightly the smaller, the integument at the lower side is merely thickened
(fig. a'), but in the larger the rays themselves are stouter, bent outwards and covered
below with a white and callous cushion-like enlargement of the skin (fig. a). All the
specimens are females.

Scales cycloid, regularly arranged ; lateral line straight, running along the middle of
the body and tail.

The stomach is short and csecal ; the intestine makes first one bend to the left and
then another to the right, is short and of moderate width. Two short pyloric appendages
opposite to each other behind the pylorus. Ovaries closed and elongate sacs. Ova of
the size of hemp seed. A long spindle-shaped urinary bladder lies above and on the left
side of the intestine. Air-bladder absent.

Scopelus, Gthr.

The numerous species which I refer to this genus, are, as far as we know of their
habits, nocturnal pelagic surface fishes, which are frequently caught at night in the

196 THE VOYAGE OF H.M.S. CHALLENGER.

surface net, but disappear during the daytime, when they evidently descend to a depth
to which only a moderate amount of light penetrates. A few, like Scopelus macro-
lepidotiis, and, perhaps, Scopelus glacialis, undoubtedly belong to the bathybial fauna,
but with regard to the other species admitted in this Report, I consider it equally
probable that they accidentally entered the dredge during its ascent. Only a few
specimens were captured in this manner, much fewer than of Argyropelecus, a fact
which is no doubt due to their greater activity, by which they are enabled to make their
escape on perceiving the approach of the net.

Scopelus macrolepidotus (Johnson).

Of this fine and large species, which hitherto was known from Madeira, six specimens,
from 6^ to 8 inches long, were obtained at the Kermadec Islands, Stations 170 and
170a, in 520 and 630 fathoms.

Scopelus glacialis.

Scopelus glacialis, Reinh., Nilss., Krdy.

Seopelun mUlleri'^ (GmeL) Collett, Norges Fisk., p. 152; Norsk. Nordh. Exped. Fisk., p. 158.
„ „ Goode and Bean, BuU. Mus. Comp. ZoiJl., vol. x., 1883, p. 222.

This species, which has been not rarely observed as a surface fish in the northern seas,
is stated by Collett to have been obtained by the North Atlantic Expedition in a
dredge, which was worked at a depth of 1110 fathoms. The U.S. steamers took it
frequently at depths of 300, 400 and 600 fathoms ofi" the southern shores of New England
and off the coast of South Carolina. All the specimens were in a more or less injured
condition, as if they had been dragged a long way through the water, and as Collett
found in their stomach an Ostracod (Conccecia horealis) which is not found at a less
depth than 300 fathoms, it is highly probable that this species is bathybial.

Scopelus antarcticus (PI. LI. fig. D).

Scopelus antarcticus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol ii. p. 184.
D. 15. A. 20. P. 13. V. 9. L. lat. 38.

The height of the body is two-ninths of the total length (without caudal) ; the length
of the head is contained thrice and two-thirds in it, the depth of the head equals its
length without snout. The diameter of the eye is somewhat more than one-third of the
length of the head; distance between the posterior margin of the orbit and the prse-
opercular edge one-third of the diameter of the eye. Snout short, obtuse, with its upper

1 There is no advantage to be gained in abandoning a well established specific name for an nncertain nomenclature.
Our best thanks are due to Hr. Collett for having unravelled the confused history of the first knowledge of these
northern Scopeli, but, even if no confusion had taken place in Strom's account, I should hesitate to supersede a name
given by an original observer like Reinhardt, by another which is proposed by a mere compiler.

REPORT ON THE DEEP-SEA FISHES. 197

profile descending in a strong curve and with the jaws nearly equal anteriorly. The
maxillary reaches to below the posterior margin of the eye, and is strongly dilated behind.
Cleft of the mouth oblique. The origin of the dorsal fin is nearer to the end of the
snout than to the root of the caudal, behind the base of the ventrals; its last ray is in
the vertical from the fourth or fifth anal ray. The pectoral fin extends to the middle
of the ventral, the ventral to the vent. Scales smooth, deciduous. There are seven
round pearly-looking patches between the adipose fin and the caudal.

The phosphorescent organs are arranged in the following manner : — Two behind the
prseopercular margin opposite to the extremity of the maxillary ; a straight series of five
between the isthmus and the root of the ventral, continued behind the ventrals to the
vent as a series of four ; somewhat higher up the side another series begins in front of the
root of the ventrals ; it consists of seven spots, the two last of which are above the vent ;
two in front of the root of pectoral ; and an isolated one below the lateral line, about
the middle of the body ; a series of twenty runs along each side of the anal fin and the
lower edge of the tail, the last two occupying the base of the rudimentary caudal rays
and being separated from those more anterior by a short interspace. A single series of
six or seven large pearl-coloured spots occupies the back of the tail behind the adipose
fin. None of these spots have a black septum, and it is also to be remarked that one
or the other which is present on one side may be rudimentary or entirely absent on the
other. In specimens which have lost a portion of their scaly integuments, some of the
organs are generally lost also.

Habitat. — Antarctic Ocean, Station 156 ; depth, 1975. One specimen, 3| inches long.

Antarctic Ocean, Station 157 ; depth, 1950 fathoms. One specimen, 2|- inches long.

This species has so much the appearance of a surface Scopelus, that I strongly suspect
that it did not actually come from the immense depth to which the dredge descended on
the occasion of the capture of the specimens, but that these entered the dredge whUst
it was being hauled to the surface.

Scopelus engraulis, n. sp. (PI. LI. fig. C).

D. 14. A. 14-15. P. 12. V. 9. L. lat. 38. L. trans. 3 | 5.

Habit rather slender, the height of the body being nearly one-fifth of the total length
(without caudal) ; the length of the head is contained thrice and two-thirds in the same.
The shape of the head reminds one of many species of Engraulis, the eye being situated
near to the extremity of the very short snout. The diameter of the eye is one-fifth of
the length of the head, and longer than the snout. Interorbital space wider than the
orbit. Posterior margin of the prteoperculum oblique. Operculum thin, narrow, scarcely
covering the gill-aperture. Mouth oblique, very wide, the upper jaw overlapping the
lower ; the maxillary extends back to the mandibulary joint and is not dilated behind.

198 THE VOYAGE OF H.M.S. CHALLENGER.

The origin of the dorsal fin is midway between the extremity of the snout and the
adipose fin, a little in advance of the root of the ventral ; its last ray is in advance of
the vent. Pectoral fin short, not extending to the ventrals. Scales perfectly smooth,
those of the lateral line not larger than the others. Lateral luminous spots at some
distance below the lateral line.

Black ; mandibles whitish, with a black cross-band below the eyes.

The phosphorescent organs are arranged in the following manner : — One on the praeo-
perculum, near to its lower angle ; three between the root of the pectoral and the isthmus ;
one above the pectoral ; three in a series on each side of the median line of the abdomen
in front of the ventrals, and an isolated one higher up on the side ; three on each side of
the median line of the abdomen between the ventrals and the vent, and two or three others
higher up the sides ; three in an oblique series running from the vent towards the lateral
line ; a series of eleven along the base of the anal and on each side of the lower part of the
tail ; one higher up the side opposite to a break in the series last described ; and four
on the root of the lower caudal rays. All these eye-like pearl-coloured organs are divided
into two by a septum of black pigment. A large whitish, gland-like organ occupies the
place in front of the eye below the nostrils.

Habitat. — Philippine Islands, Station 200 ; depth, 250 fathoms. One specimen,
6|^ inches long.

Scopelus duvierihi.

Scopelus dumerilii, Bleek., Act, Soc. Sci. Iiido-Neerl., i., Manado en Makassar, p. 66.
D. 14-15. A. 14-15. P. 10. V. 9. L. lat. 37.

This species is closely allied to Scopelus engraulis, and for some time I was inclined
to refer the following specimen to that species, taking the larger size of the eye merely as
a sign of its immaturity, but the difference in the position of the lateral phoshorescent
organs seems to indicate specific distinctness.

The diameter of the eye is two-sevenths of the length of the head, equal to the width
of the interorbital space and much more than the length of the snout. The origin of
the dorsal fin is rather nearer to the adipose than to the end of the snout. Pectoral
fin reaching somewhat beyond the root of the ventral, and the latter beyond the
anterior anal rays. The phosphorescent spots are arranged as in Scopelus engraulis, but
the four which are placed on the sides are not at a distance below the lateral line, but
almost on it, one corresponding to the root of the pectoral, the second to that of the
ventral, the third to the origin, and the fourth to the end of the anal fin. None of the
organs have a black septum in this species.

Habitat. — Off Matuku, Fiji Islands, Station 173; depth, 315 fathoms. One specimen,
3 inches long.

REPORT ON THE DEEP-SEA FISHES. 199

NannobracMum, n. gen.

Head and body rather elongate and compressed, covered with deciduous scales of
rather large size. Cleft of the mouth very wide ; maxillary well developed, not dilated
behind. Teeth minute, in narrow bands, in the jaws, on the vomer, the palatine bones,
and the tongue. Eye rather small. Pectoral fins rudimentary ; ventral fins well
developed, eight-rayed, inserted at some distance behind the pectorals ; dorsal fin in the
middle of the length of the body with fourteen rays, its origin being between the ventrals
and the anal ; adipose fin small ; anal of moderate length ; caudal forked. Gdl-opening
very wide ; pseudobranchise small. Series of phosphorescent organs along the lower side
of the head, body and tail ; a gland-like luminous organ on the upper and lower sides of
the caudal peduncle.

Habitat. — Indian Ocean.

NannobracMum nigrum, n. sp. (PI. LII. fig. B).

D. 14. A. 19. L lat. ca. 34.

The single specimen in the collection has sufi"ered much at the time of capture and
has lost a great portion of its integuments.

This fish is closely allied to Scopelus, and bears in its physiognomy and general form
of body a great resemblance to Scopelus engraulis. The depth of the body is contained
five and a half times in the total length, without caudal, the length of the head three
times and two-thirds. A great portion of the skuU is cartilaginous, the superficial bones
Ijeing extremely thin and modified for the reception of the wide muciferous cavities.
The eye is rather small, about one-fifth of the length of the head and equal to that of
the snout. Mouth extremely wide, rather oblique, with the lower jaw somewhat
projecting, extending backwards to the end of the prseoperculum. Intermaxillary as
long as maxillary, toothed throughout its whole length, both bones being very narrow and
rod-shaped. Hind margin of the prasoperculum very oblique.

Gill-lamina very short; gill-rakers long, needle-shaped, eighteen on the outer
branchial arch, the longest as long as the eye.

The origin of the dorsal fin is nearer to the extremity of the snout than to the root
of the caudal, and its last ray opposite to the eighth of the anal fin. Adipose fin narrow,
opposite to the end of the anal. The origin of the anal is opposite to the eighth ray
of the dorsal fin. Caudal emarginate.

The pectoral fin is reduced to three or four small and extremely delicate filaments.

The ventral fin is inserted consipcuously in front of the dorsal and extends backwards
to the vent.

200 THE VOYAGE OF H.M.S. CHALLENGER.

The eye-like phospliorescent organs are small and arranged very much in the same
manner as in Scopelus engraulis, but owing to the condition of the specimen no exact
description of their number can be given. A long, linear, glandular organ of white
colour occupies the back and opposite side of the posterior half of the caudal peduncle.

Coloration uniform black.

Habitat. — South of Philippine Islands, Station 214 ; depth, 500 fathoms. One
specimen, 4J inches long.

Odontostomus, Cocco.

Body oblong, compressed, naked ; head compressed, snout short ; cleft of the mouth
very wdde ; intermaxillary and maxillary bones slender, the former with a series of small
teeth of equal size which have their points directed backwards ; the lower jaw, the vomer
and the palatine bones armed with a few very large curved and lanceolate teeth, which
are barbed at the tip, curved, and depressible backwards. Eye very large, with the
orbital cavity expanded downwards, so that the eye can be turned either upwards or
towards the side of the head. Pectoral and ventral fins well developed, the latter are
inserted below the dorsal at some distance behind the pectoral. Dorsal fin in the middle
of the length of the body ; adipose fin small, placed far backwards ; anal fin long ;
caudal forked. Branchiostegals eight ; pseudobranchias well developed, gUls four ; the
outer branchial arch with small gill-laminse and without giU-rakers.

Odontostomus hyalinus, Cocco (PL LII. fig. A).

D. 12, A. 34. P. 12. V. 9.

The height of the body is contained six times and one-third in the total length,
without caudal, the length of the head four times and a half. The wide cleft of the
mouth, which is oblique, extends far beyond the eye, but does not reach the angle of the
pra3operculum. The mandible is broad, not attenuated in front, and projects beyond the
mouth. The large fangs can be depressed backwards, and are always depressed when
the mouth is closed ; they are very much compressed and sharp- edged in front and
behind. The longest of the palate have their extremities curiously bent forward.

The form and structure of the orbit is quite unique ; it is, in fact, turned upwards,
separated from its feUow by an extremely narrow interorbital space ; its lateral wall is
formed by a transparent membrane so that the fish by rotating the eye-ball behind this
membrane outwards for 90°, can place the eye in the usual position on the side of the
head, and thus see either sidewards or upwards. The infraorbital ring is very narrow,
bent in a strong curve, within which the transparent orbital membrane is extended.

EEPORT ON THE DEEP-SEA FISHES. 201

The eye is large, but shorter than the snout and less than one-fourth of the length of the
head.

Origin of the dorsal fin a little nearer to the extremity of the snout than to the root of
the caudal ; it is higher than long. The anal fin commences at some distance behind the
vent, which occupies a position midway between the ventrals and the anal, and somewhat
behind the vertical from the last dorsal ray. The anal fin is lower than the dorsal and
terminates close to the anterior rudimentary rays of the caudal fin. The adipose fin is a
small narrow lobe. Pectoral fin inserted close to the ventral profile, truncated behind,
and terminating at some distance from the ventral fin. Ventral fins inserted somewhat
behind the vertical from the origin of the dorsal fin, shorter than the pectorals, and
extending to the vent.

This fish is colourless in spirits, but covered all over with brown pigment spots.

The description is taken from a specimen, 6^ inches long, obtained near Nice.

Omosudis, n. gen.

Body oblong, compressed, naked ; head compressed, snout of moderate length, cleft
of the mouth very wide, intermaxillary and maxillary bones slender, the former with a
series of very small teeth of equal size, only one or two anterior ones being somewhat
enlarged ; the lower jaw, the vomer and palatine bones with a few very large and
lanceolate teeth. Lower jaw broad, and like the rest of the head formed of very thin
bone. The supraclavicle and postclavicles form a long rod extending from the occiput
on each side downwards to the abdomen, and partly free, not covered by skin. Ventral
fins inserted far behind the pectorals below the origin of the dorsal. Dorsal fin behind
the middle of the length of the body ; adipose fin very small ; anal fin long. Stomach
very distensible. Branchiostegals eight ; pseudobranchise well developed ; gills four,
with broad gill-laminse and very short gill-rakers.

Omosudis lowii, n. sp. (PI. LII. figs. C, C).

B. 8. D. 9. A. 14. P. 12. V. G. (?)

The length of the head is two-sevenths of the total length, without caudal ; the
greatest depth of the body immediately behind the head is one-fifth of the total length.
The head is strongly compressed, with rather flat upper surface ; snout somewhat pointed,
rather longer than the eye, the diameter of which is one-third of the length of the head.
The bones of the head are extremely thin, the operculum being smaller than the suboper-
culum and supported by two or three ridges. The infraorbital ring is nearly membran-
aceous. Praeoperculum terminating below in a forked point. Cleft of the mouth
extending backwards to the angle of the prseoperculum.

(ZOOL. CHALL. Exr. — PART LVII. — 1887.) Lll 26

202 THE VOYAGE OF H.M.S. CHALLENGER.

The dentition is truly formidable for so small a fisli ; the longest tooth is one
anteriorly on the side of the mandible ; in both our specimens only one is present
either on the right or left of the jaw ; its length is nearly one-third of that of the head.
The next largest are those on the palate, where there are two on each side, beside several
smaller ones. Smaller teeth are also implanted on the hinder part of the dentary bone.
AU the large teeth can be laid backwards.

A semicircular scale-like osseous lamella of extreme thinness covers the lower part of
the cheek and is marked by very shallow concentric striae.

The singular bone which supports the side of the anterior part of the abdomen is
styliform, slightly curved backwards. It starts from the top of the
occiput and descends towards the median line of the abdomen, which
it reaches behind the pectoral fin. It is composed of the two-
pronged supraclavicle (sd) which is fixed by ligaments to the
occiput, and of three slender and needle-shaped postclavicles (pel) ;
the uppermost post-clavicle is suspended by ligaments from the
supraclavicle, as is also the clavicle (cl). The rod lies immediately
below the thin integument and its lower portion is quite free.
Fig. 6.— Scapular arch of The dorsal fin commcuccs mid Way between the root of the

Omosudis (enlarged). tit.t t • if r ^ i ,^ i

caudal and the eye, and is composed oi very leeble rays ; the anal
commences at some distance behind the dorsal and terminates not very far from the
caudal. Caudal fin small, with a considerable number of basal rays above and below.
Pectoral fins quite at the lower side of the body ; ventral fins very small and partly
coalescent.

Light brownish on the back with numerous brown pigment spots on the sides ;
abdomen black.

One of the two specimens (fig. C) has the abdomen excessively distended, having
swallowed a Sternoptyx equal in bulk to its destroyer, and with a body the width of
which is about twice that of the Omositdis. In the other specimen the abdominal
integuments are longitudinally folded.

One specimen, 3^ inches long, was obtained south of the Philippine Islands, at
Station 214, in a depth of 500 fathoms. But the existence of this singular form
has been known to me since 1868, in which year I received from my late friend, the
Rev. E. T. Lowe, a somewhat smaller example, which he had obtained at his favourite
station, Magdalena, in the year previous. That specimen had its abdomen distended by
the contents of its stomach, and was probably killed by the dorsal spike of the Sternojityx
penetrating the walls of the abdomen. Not only the head but also the hind part of the
body were so much distorted and injured that it did not seem to me advisable to describe
the genus from this specimen.

REPOET ON THE DEEP-SEA FISHES. 203

Plagyodus, Steller.

No specimen of this characteristic deep-sea type was obtained during the Challenger
Expedition ; indeed, no example is known to have been captured by means of the
dredge or trawl. The Madeiran species is rarely caught on the deep-sea lines of the
fishermen, whilst the other species seem to be known from examples that were found
floating on the surface or thrown ashore. The following species are known : —

Plagyodus ferox.

Alepisaurus ferox, Lowe.

Known from the depths of the Atlantic only ; a fragmentary skull from Tasmania
indicates the presence of this species in the South Pacific.

Plagyodus ^sculapius.

Alepisatcms aeseulapius, Bean, Proc. U.S. Nat. Mus., 1883, p. 661.
Alaska.

Plagyodus altivelis.

Alepisawvs altivelis, Poey, Mem. Cub., vol. ii. 302.
Cuba.

Plagyodus horealis.

Caulopus borealis. Gill, Proc. Acad. Nat. Sci. Philad., 1862, p. 128.

Pacific Coast of North America.

Family Stomiatid^.

Astronesthes, Eich.

Astronesthes niger, Eich.

Habitat. — Near Sierra Leone, Station 101; depth, 2500 fathoms. Two specimens,
l^ inches long.

West Coast of Africa, April 28, 1876. One specimen, 1^ inches long.

This little fish is one of the most common of pelagic forms in the Atlantic as well as in
the Indian Ocean, and therefore is caught on almost every voyage on which the tow-net

204 THE VOYAGE OF H.M.S. CHALLENGER.

is used. From the development of its luminous organs, which cover in great number not
only the lower but also the lateral parts of the body, we may infer that its habits are
nocturnal. It is not known to what depth it descends during the daytime, but it is
very improbable that the two specimens from Station 101 were caught at the depth of
2500 fathoms.

No more is known about the habits of the other species of the genus which have
been described, viz., Astronesthes richardsonii (Poey), Astronesthes barbatus (Kner),^
Astronesthes martensii (Klunz.), Astronesthes clirysophehadion (Blkr.)."

Stomias, Cuv.
Stomias boa.

Esox boa, Risso.

Stomias boa, Cuv. Val., vol. xviii. p. 368, fig. 545.

„ barbatus, Cuv., Efegne animal.

,, „ Bonap., Faun. ital. Pesc. (c. fig. mala).

1 refer to this species a specimen obtained south of Australia, Station 158, in 1800
fathoms, as it agrees with the only detailed and reliable description and figure which
have hitherto been given of the Mediterranean fish, viz., by Valenciennes. Peters^ also
states that he has not found any diflference between a specimen from Nice and one from
the Pacific, caught in lat. 42° 56' S., and long. 149° 26' W. However, I must not omit
to mention that none of the authors referred to have given the number of luminous
spots along the abdomen, and that, not having a specimen from the Mediterranean, I
am consequently unable to assert the agreement of our fish in this respect ; also that
Valenciennes has counted seventy-two scales along the side of the body, whilst our
Antarctic specimen possesses eighty-eight. Ussow,* in his valuable contribution to our
knowledge of the structure of the luminous spots, states that Stomias barbatus and
Stomias anguilliformis'' possess fifteen luminous spots in a series from the caudal fin
to the anal, thii-ty-five from the anal to the ventral, and twenty-two from the ventral to
the pectoral. But these numbers difi"er so much from my own observations that I
cannot help thinking that by some error the numbers were confused in his table.

As a full description has been given of Stomias elsewhere, I append here only a
diagnosis taken from the Antarctic specimen.

''■ = Stomias leucopterus, Eyd. and Soul., Voy. Bonite. Zool., torn. i. p. 193, pi. vii. fig. 4.

2 A fish mentioned and figured in La Nature, 1884, p. 185, under the name of " E astomias obscurus (N. S. N. S.,
L. Vaill.)," is not characterised, but the figure represents it witli a long barbel terminating in a phosphorescent button-
like swelling ; it was captured in the Atlantic during the voyage of the " Talisman " at a depth of 2700 metres.

2 Monalsber. d. k. prexiss. Akad. d. JViss. Berlin, 1876, p. 846.

* Bull. Soc. imp. des Nat. Moscou, 1879, p. 108.

^ A name for which I have unsuccessfully searched ichthyological literature.

REPOET ON THE DEEP-SEA FISHES. 205

D. 18. A. 18. P. 6, V. 5. L. lat. 88.

The height of the body is contained twelve and a half times in the total length, with-
out caudal, the length of the head nine and one-third times. Barbel as long as the
head, terminating in three filaments. Pectoral and ventral fins very narrow and
elongate. Each of the median abdominal series of luminous spots contains fifty-four
between pectoral and ventral fins, fourteen between ventral and anal, and fifteen
between the origin of the anal and caudal.

Stomias affinis, n. sp. (PL LIV. fig. A).

D. 17. A. 20. P. 6. V. 5.

Scaleless, but with the hexagonal divisions of the skin distinct. The height of the
body is one-twelfth of the total length, without caudal, the length of the head one-
eighth. Teeth fixed. The barbel is about as long as the head, and terminates in three
filaments (fig. a); the end of the stem of the barbel white, with a black pigment-spot,
and probably luminous. Pectoral and ventral fins narrow and elongate, especially the
latter, which taper into a filament and extend beyond the anterior anal rays. Anal fin
higher than dorsal. Each of the abdominal series of luminous spots contains forty-three
between the pectoral and ventral fins, six between ventrals and anal, and fifteen (sixteen)
between the origin of the anal and caudal ; another parallel series runs below, and a
third above the middle of the side of the body. Fins white, dorsal, anal and ventrals
with black margins.

Habitat.— South, of Sombrero Island, Station 23; depth, 450 fathoms. One
specimen, 5 inches long.

Stomias ferox (Reinh.).

D. 17. A. 21. P. 6. V. 6.

The height of the body is about one-twelfth of the total length, the length of the
head one-tenth. The barbel is longer than the head, tapering and not fringed at its
extremity. Neither the pectorals nor the ventrals are produced.

Discovered first in the sea off the coast of Greenland ; other specimens were recently
obtained further southward, viz., in lat. 40° 0' to 41° 30' N., long. 65° 0' to 68° 0' W.;
at depths of 304 and 524 fathoms.

206 THE VOYAGE OF H.M.S. CHALLENGER.

Echiostoma, Lowe.^

Echiostoma barbatum (PI. LIII. fig. B).

Echiostoma barbatum, Lowe. Proc. Zool. Soc. Lond., 1843, p. 88.
„ „ Giinth., Fish., vol. v. p. 427.

„ „ Goode and Bean, BulL Essex Instit., vol. xi. p. 128.

B. 12. D. 12-15. A. 16-18. P. 3-5. V. 8.

The head and body of this fish are compressed, scaleless ; its greatest depth is one-
eighth of the total length, the length of the head nearly one-seventh. The upper part of
the head is short, the cleft of the mouth very wide, extending to the angle of the
prseoperculum, the hind margin of which consequently descends backwards in a strongly
oblique direction. The opercular portion is very narrow, and the whole gill-cover formed
by thin, almost membranous plates. The width of the interorbital space much exceeds
that of the orbit, the diameter of which is one-sixth of the length of the head, and a
little less than that of the snout. Lower jaw but slightly projecting beyond the upper.
Nostrils, two round openings on each side, situated in a cavity on the upper side of the
snout, and separated from the orbit by a slight crenulated projection ; also the median
ridges on the upper side of the head are indistinctly crenulated.

The formidable dentition consists of pointed teeth unequal in size, chiefly arranged
uniserially, all the larger ones being depressible backwards or inwards. The two large
front teeth of the upper jaw leave a wide space for the reception of the lower teeth.
When complete, the intermaxillary dentition consists of ten teeth, of which the first is
the smallest and readily lost, the third and sixth the largest. The maxillary dentition is
peculiar, inasmuch as its proximal third consists of six teeth of moderate size, while the
two distal thirds are formed by uniformly small teeth, there being no gradual transition
from the larger to the smaller teeth. The mandibulary teeth are uniserial in front,
biserial behind; the seven anterior teeth are larger than the rest, and the third and
sixth exceed the others. Vomer with a fang on each side ; palatine with a series of
small teeth. Two pairs of fangs, strongly curved backwards, on the tongue. Also the
upper pharyngeals bear some teeth of rather small size.

The gill-laminae are well developed, except on the hinder part of the horizontal

1 This genus seems to have been re-named Hyperchoristus (Gill, Proc. U.S. Nat. Mus., vol. vi. 1884, p. 256); its
dentition is described thus : — " Teeth on the jaws nearly uniserial, but in several groups, of which the successive teeth
(about four) rapidly increase in size backwards, and teeth on the palate enlarged, one on each side of the vomer, and
several on the palatines." A single specimen, named Hyperchoristus tanneri, of which the size is not stated, was
obtained by the U.S. Fish Commission in the North Atlantic (lat. 40° 26' N., long 66° 58' W.), at a depth of
956 fathoms; but as the specimen is said to have been "so lively when brought to the surface that it twisted itself
round in its attempt to bite the commander of the vessel," it is more likely to have been captured much nearer to the
surface of the water.

REPORT ON THE DEEP-SEA FISHES. 207

branch of the outer branchial arch, where they are remarkably short ; gill-rakers in
quite a rudimentary condition.

The barbel is of nearly uniform thickness, and scarcely more than half as long as the
head ; it is inserted somewhat behind the anterior extremity of the hyoid bone, and
seems to have terminated in a short, small, black lobe.

The vent is placed very far backwards, its distance from the root of the caudal not
much exceeding that between the pectoral fin and the end of the snout. The anal
commences immediately behind the vent, and its depth, as well as that of the dorsal, is
less than that of the tail between these two fins. The dorsal fin is shorter than the anal,
commencing a little behind, and terminating in front of, the anal. Caud^il short, cleft
with pointed lobes. Pectoral very narrow, its upper ray is separate from the remainder
of the fin, and produced into a very long and exceedingly fine filament, which nearly
reaches the ventral. Ventrals very narrow, pointed, and somewhat longer than the
head ; the distance of their base from the end of the caudal equals that from the root of
the pectoral.

The luminous organs ^ are arranged thus : —

a. A series of rather small, but distinctly developed eye-like bodies begins on the
isthmus, and runs along each side of the abdomen to the commencement of the anal fin ;
it consists of eight in front of the pectoral, twenty-nine between pectoral and ventral,
and fifteen between ventral and anal.

6. A parallel series, beginning above the root of the pectoral, and running below
the median line of the side of the body along the base of the anal to the root of the
caudal. The position of the organs corresponds to that in series a ; but there are twelve
additional posterior ones, from the commencement of the anal to the root of the caudal.

c. A series of similar organs along the base of the branchiostegals.

d. Innumerable smaller, and partly quite rudimentary, organs are scattered between
the principal series ; they extend upwards on the sides to the back, but they are there
more regularly arranged, a biserial row corresponding to each myocomma. A great
number of rudimentary organs, hke raised pigment-spots, are scattered all over the head.

e. An isolated eye-like organ, larger than any of the others hitherto described,
occupies the suture between operculum and suboperculum.

/ The principal luminous organ, situated behind the eye, along the maxillary, is of
a narrow cuneiform shape, pointed behind, and longer than the eye ; it is said to be
rose-coloured during life.

Colour, uniform black.

Habitat. — Very rare at Madeira, where the only specimen I have seen was obtained ;
it is 9 inches long. Another example is reported to have been taken ofi" the coast of
Massachusetts.

1 The result of their histological examination will be given in Appendix B.

208 THE VOYAGE OF H.M.S. CHALLENGER.

Opostomias, n. gen.

This genus differs from Echiostoma by its dentition, the long teeth not being
depressible, but received in grooves or hollows of the opposite jaw. Maxillary and
palatine teeth absent. A barbel.

Opostomias micripnus (PI. LIII. fig. A).

Echiostoma micripnus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 180; Narr. Chall.
Exp., vol. i. p. 412.

B. 15. D. 21. A. 23. P. 1 I 3. V. 7.

The length of the head is nearly one-ninth of the total (with the caudal). Barbel
much longer than the head and fringed at its extremity ; the anterior pectoral ray
filamentous and distinctly separated from the others. Boot of the ventral rather nearer
to the extremity of the snout than to the root of the caudal. Black ; luminous organ
above the maxillary small, round, like a rudimentary eye.

Habitat. — South of Australia, Station 159; depth, 2150 fathoms. One specimen,
15^^- inches long.

The height of the body is one-eighth of the total length, the length of the head two-
ninths. Head moderately compressed ; interorbital space convex, broad, its width being
contained twice and two-thirds in the length of the head. Cleft of the mouth wide, but
not quite extending to the angle of the prseoperculum, the posterior margin of which is
vertical. Gill-cover completely covering the gill-cavity, narrow. Eye small, half as long
as the snout and one-sixth or one-seventh ' of the length of the head.

Jaws armed with very strong teeth, few in number and not depressible. About one-
half of the length of the upper jaw is formed by the intermaxillaiy and the other half
by the maxillary. The intermaxillary bears four teeth, of which the second is by far
the strongest and received in a shallow impression behind the large fang of the mandible.
The three other teeth are subequal and of rather small size. Maxillary toothless.
Mandible broad and deep, armed anteriorly with two large and pointed fangs, which are
distant from each other and are received in a deep hollow of the upper jaw. This
large mandibulary fang is succeeded by three teeth only, which are remote from each
other and somewhat larger than the opposite teeth of the upper jaw. Vomer with a
small fang on each side. Palatines toothless ; upper pharyngeals with some small

fangs.

Pupil of the eye vertical. Nostrils close together, above the eye, on the upper surface
^ The eyes are not exactly of the same size on each side.

EEPORT ON THE DEEP-SEA FISHES. 209

of the snout. The barbel is inserted in front of the extremity of the hyoid bone ; it
is much longer than the head and terminates in a luminous organ, from which a short
terminal filament arises.

Gills four, well developed, the laminse on the posterior part of the horizontal branch
of the outer branchial arch being shorter than the others. GUl-rakers in the shape of
short spiny tubercles.

The distance of the vent from the root of the caudal is twice the length of the head.
The anal fin commences immediately behind it, and terminates so close to the caudal that
the extremities of some of its posterior rays touch it. The dorsal is coterminal with the
anal in front, but does not extend quite so far backwards ; both fins are about equal in
height and lower than the tail between them. Caudal fin short, cleft, the lower lobe
being the stronger. The upper pectoral ray is separated from the remainder of the fin
by a short interspace ; it is about as long as the head and has the terminal portion
covered with a white luminous substance. The pectoral fin proper is extremely narrow,
short, and in fact rudimentary. Ventrals much more developed, as long as the head ;
their root is nearer to the extremity of the snout than to the root of the caudal, but
rather nearer to the vent than to the gill-opening.

The skin is naked, with conspicuous mucous openings on the top of the head, and a
great number of luminous organs * which are arranged as follows : —

a. A series of small eye-like organs, which commences on the isthmus and runs along
each side of the abdomen to the root of the caudal fin. It consists of five very
small organs on the isthmus, thirty between the pectoral region and the ventral fin,
twenty-two between the ventral fin and the vent, and about sixteen between the vent
and the root of the caudal. Of these latter posterior organs some may be occasionally
missing, all being very small.

h. The upper lateral series consists of eye-like organs, which in size and position
generally correspond to those of the former series, but there is now and then a break in
the series by one or more of the organs being absent. This series disappears altogether
opposite to the anal fin.

c. A series of similar organs along the base of the branchiostegals.

d. An eye-like organ, isolated and somewhat larger than those described, between
the operculum and suboperculum.

e. A still larger organ, between the upper jaw and the eye, so closely simulating an
eye, that, from its external appearance, a cornea, iris, and pupil might be distinguished.

/ A great number of minute organs, some with a lighter centre, others being merely
raised pigment-spots, scattered over the whole body and head.

g. It has been already mentioned that the terminal portions of the barbel and
pectoral filaments are covered and slightly thickened by a layer of white luminous

2 The histology of these organs is described in Appendix B.

(ZOOL. CHALL. EXP. PART LVII. — 1887.) ^11 -7

210 THE VOYAGE OF H.M.S. CHALLENGER.

substance ; and it appears that there is a large patch of similar substance in the gill-
cavity on and in front of the clavicle.

The entire specimen is black, the vertical fins of a somewhat lighter colour; the upper
central rays of the caudal black. Ventrals whitish, the hind part of the three inner rays
black.

Mr. Murray ^ observes : — " The end of the barbel, which was thickened, was flesh
colour with a rose tint, there was also a rose tint on the dorsal and anal fins. The rest
of the animal was of a dark colour with a perceptible slate-coloured tint. The phosphor-
escent spots along the belly and lateral line were red, as was also that below the eye,"

Pachystomias, n. gen.

This genus diflFers from Echiostoma by the absence of a separate pectoral ray; also by
a much less developed dentition, vomerine and maxillary teeth being absent,

Pachystomias microdon (PI. LIII. fig. C),

Echiostoma microdon, Giintli., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 180.

D. 24. A. 29. P. 3. V. 7.

The length of the head is more than one-fifth of the total (with the caudal). No
separate pectoral ray ; root of the ventral considerably nearer to the base of the caudal
than to the extremity of the snout. All the teeth rather small, a few only in the middle
of the palatine bone. Black ; two luminous organs below the eye, a narrow elongate
one above the maxillary, and a small short one nearer to the eye.

Habitat. — North-West of Australia, Station 181 ; depth, 2440 fathoms. One
specimen, 9 inches long,

* This fish is a much shorter and heavier fish than Echiostoma harhatum, somewhat
approaching Malacosteus in its physiognomy. The head and body are compressed ; the
greatest depth, immediately behind the head, is one-fifth of the total length, the length
of the head two-ninths. The head is enveloped in rather thick skin, like the body, well
hiding the underlying parts. Upper part of the head rather short, cleft of the mouth
exceedingly wide, extending backwards nearly to the margin of the gill-opening; the
prseopercular edge is therefore very oblique. Interorbital space convex, but with a
depression along the middle caused by two longitudinal ridges ; its width equals the
diameter of the eye, which is as long as the snout, and one-fourth of that of the
head. Nostrils close together, round, lateral, in front of the eye. Snout rounded,

'Narr. Chall. Exp., vol. i. p. 412.

EEPORT ON THE DEEP-SEA FISHES. 211

with a parabolic anterior profile ; mandible tapering in front and not longer than the
upper jaw.

The dentition in the upper as well as in the lower jaws consists of a single series of
rather small teeth, not very closely set, fixed, not depressible, subequal in size, only two
pairs in front of the lower jaw being somewhat larger and strongly curved. Only
the intermaxillary is toothed. The teeth on the palate are reduced to a short series of
five small closely set teeth, which are depressed inwards and backwards.

The gill-cover is so narrow as to leave a considerable portion of the gills uncovered.
The gill-laminse are developed, except on the hinder part of the horizontal branch of the
outer branchial arch, where they are remarkably short ; gill-rakers absent.

A narrow bridge of skin behind the symphysis stretches from one mandible to the
other. Barbel small, tapering, about one-third of the length of the head, suspended from
the hyoid.

The vent is placed very far backwards, its distance from the root of the caudal being
a little less than the length of the head. The anal fin extends nearly to the caudal, a
little further backwards than the dorsal, the origin of which is opposite to that of the
anal. Behind these fins the tail is suddenly narrowed and terminates in a small bilobed
caudal fin. Pectoral fin rudimentary, its short rays being free at the tip. Ventrals
twice as distant from the eye as from the vent ; they are well develo2Jed, have a
moderately broad base, and are half as long as the head.

The skin is rather tough, scaleless, but rhombic lines are visible, especially on the
side of the back, indicating the first commencement of the development of scales. The
luminous organs ^ are arranged thus : —

a. A series of three or four minute eye-like spots on each side of the isthmus.
After a short interruption this series is continued along the abdomen by three similar
organs in front of the pectoral, by sixteen between the pectoral and ventral, and by
fourteen or sixteen between the ventral and anaL

h. The lateral ventral series consists of similar organs, but still more minute in size,
and more or less disappearing at the level of the anal fin.

c. A vertical series of three much larger eye-like organs on the gill-cover ; they do
not possess the white centre of those described hitherto, but appear through a rather
opaque round cornea-like membrane.

d. The large subocular organ which consists of two portions, one being elongate, as
long as the eye and lying close to the intermaxillary ; the other much shorter, between
the anterior end of the former and the front margin of the eye. Eacli of these organs
is of a pure white colour, has free margins all round, and lies in a hollow of the skin of
corresponding shape.

Colour uniform deep black.

' The histology of these organs is described in Appendix B.

212 THE VOYAGE OF H.M.S. CHALLENGER.

Mr. Murray ^ observes : — " The new sj)ecies of Echiostoma showed signs of life
when taken out of the trawl, so that probably it had not come from any great depth.
It had one club-shaped spot of a rose colour directly below the eye, and another, about
half the size, directly in front of this, of the same colour ; these spots turned yellow in
spirit. The two rows of probably phosphorescent dots along the body were red,
surrounded by a circle of pale violet ; these dots turned white in spirit."

Photonectes.
Lucifer,^ Doderlein, Wiegm. Archiv f. Naturgesch, 1882, p. 26.

Body compressed, rather long, scaleless ; vent far behind the middle of the length.
Head compressed, with short snout and exceedingly wide mouth. Teeth in the jaws
small, unequal in size, in single series ; vomer and palatine with a small group of teeth
on each side. Eye small. Opercular portion of the head very narrow. A long hyoid
barbel. The dorsal fin opposite to the anal, which commences behind the vent.
Pectorals none. Ventrals inserted behind the middle of the length. A small suborbital
phosphorescent organ, and two series of luminous dots along the lower part of the sides,
with numerous rudimentary similar organs scattered over the skin of the body.

Photonectes alhipinnis.

Lucifer dlMpennis, Doderlein, loc. ciL, pi. iii.

D. 13. A. 15. P. 0. V. 7.
Black, with white fins.
Known from a single example from Inosima, 9 inches long.

Malacosteus, Ayres.

This form is one of the most extraordinary types of deep-sea fishes, reminding us in
certain respects of the Bathybial Pediculates and Gadoids (Chiasmodus). Eesembling a
Stomiatid in its principal characters and general appearance of the body, Malacosteus
possesses an osseous framework of a very soft, semicartilaginous or membranous structure ;
its integuments and fins are extremely fragile and loosely connected. The whole of its
cranial bones are remarkably reduced in size and development, with the exception of
those required for seizing and holding its prey. The snout is so short as to remind us of
those monstrosities of carps or trout, in which the anterior facial portion of the cranium
is missing ; whilst the jaw-bones and the prseoperculum are greatly prolonged, forming
1 Narr. Chall. Exp., vol. 1. p. 521. 2 Preoccupied for a genus of Crustacea.

REPORT ON THE DEEP-SEA FISHES, 213

an enormous gape wliicli extends Iwckwards beyond the base of the pectoral fins. On
the other hand, the gill-cover is still more reduced than in the other Stomiatids, and
quite rudimentar)''.

A perfectly unique structure is a thin, cylindrical, muscular band which connects the
back part of the mandibulary symphysis with the extremity of the hyoid bone. It is
probably the homologue of a muscular band which in other Stomiatids stretches on each
side from the mandible to the side of the hyoid, the two bands coalescing into an un-
paired one in Mcdacosteus. It is, in the present state of preservation, much elongate,
like a barbel, but during life it is probably contractile and serves to give to the extremity
of the mandible the requisite power of resistance when the fish has seized its prey, as
without such a contrivance, so long and slender a bone would yield to the force of its
struggling victim. This structure is so unique, and the band so similar to a barbel
that, before having become acquainted with it by autopsy, I imagined that its original
describer, Dr. Ayres, had misunderstood its character, and that he had only seen a
barbel like that of Stomias or Echiostoma. Dr. Ayres had not made any suggestion as to
its probable function.

Being provided with a mouth which allows of the passage of fishes much exceeding
in size its own bulk, Malacosteus must have as distensible a stomach as Chiasmodus or
Omosndis. Both the specimens which are known had the stomach empty, but in
our example the integuments of the abdomen are so distinctly longitudinally folded that
there can be no doubt on this point ; and probably Stomias and Pacliystomias are
likewise able to swallow large fishes, though this peculiarity is less developed in them
than in Malacosteus.

The eye is comparatively large ; and it would be quite inconceivable that a fish
living at a depth to which no ray of the sun can penetrate, should be provided with an
organ of sight so much developed, unless light be produced from some other source or by
the fish itself In Malacosteus the subocular luminous organ ^ is broken up into two bodies
imbedded in the muscular substance ; the anterior is the larger, pear-shaped, with the
narrow end directed forwards and wedged into the narrow space between the eye and
intermaxillary; the posterior is situated somewhat further back, above the maxillary,
smaller and of a more rounded form. Both are now of the colour of a crystalline
lens after immersion in spirit, and surrounded by a very narrow pearly ring.

Small eye-like organs are arranged in longitudinal series along the lower part of the
side, and scattered between the series; others are scattered over the u^jper parts, but
owing to the state of the specimen I am unable to trace the series in their whole course
or to ascertain their number.

The gills are four in number with very short laminse, and without gill-rakers; of
branchiostegals I counted eight, all extremely short, rod-like and cartilaginous.

1 Its histological structure wiU be described in Appendix B.

214 THE VOYAGE OF H.M.S. CHALLENGER.

Malacosteus niger (PI. LIV. fig. C).

Malacosteus niger, Ayres, Journ. Bost. Soc. Nat. Hist., 1849, p. 53, pi. v.
D. 19. A. 20. P. 5. V. 6.

The specimen of which Dr. Ayres has given an excellent description and figure,
was 8^- inches long, and picked up at sea in the Atlantic in lat. 42° N., long. 50° W.
Its mandible is armed with a series of slender, more or less curved teeth unequal in
size ; the largest occupy the anterior half of the bone and are four in number, a few smaller
ones being placed between them in an irregular fashion ; also the extremity of the
mandible is armed with a longer curved tooth, but shorter than the lateral large ones.
The caudal peduncle is very narrow behind, about two-thirds as long as the base of the
dorsal fin. Base of the ventral fin midway between the caudal and the posterior
luminous organ.

These are the principal characters Ijy which this fish seems to specifically difier from
its congener from the Indian Ocean.

The figure of the dentition is copied from Dr. Ayres' original drawing.

Malacosteus indicus (PL LIV. fig. B).

Malacosteus indicus, Giinth., Anu. and Mag. Nat. Hist., 1878, vol. ii. p. 181.
D. 18. A. 20. P. 2. V. 6.

The fang on the extremity of the mandible is as strong as any of the lateral teeth,
more strongly bent, and directed forwards and outwards. Of the lateral mandibulary
teeth two exceed the others in length and strength ; the anterior is at no great distance
from the terminal fang, and the space between them is filled up by three or four smaller
teeth which decrease in size forwards. The posterior large fang is more remote from the
anterior and separated from it by smaller teeth varying in size. The caudal peduncle is
less narrow than in the Atlantic species, and its length less than one-half of the length
of the dorsal fin. Base of the ventral fin nearer to the caudal than to the posterior
suborbital luminous organ. Caudal fin emarginate. Deep black.

One specimen, 4^ inches long, was obtained near the Philippine Islands (Station 214),
in 500 fathoms. It is extremely similar to Malacosteus niger, and a detailed description
is therefore rendered unnecessary by the excellent account which Ayres has given of that
sj)ecies.

Mr. Murray ^ observes : — This fish " had between the maxilla and the eye on either
side two spots, the posterior one round and of a beautiful light yellowish-green colour,
the anterior one larger, club-shaped (the head of the club pointing back), and of a dull
red colour. The specimen was .... entirely black, with minute dots over the surface. "

1 Narr. Chall. Exp., vol. i. p. 669.

REPORT ON THE DEEP-SEA FISHES 215

BathopMlus.
Bathophihis, Giglioli, Pelagos, p. 261.

Body compressed, rather short, scaleless, minutely granulated ; vent far behind the
middle of the length. Head compressed ; cleft of the mouth very wide ; teeth stout.
Eye small. Barbel none. Dorsal fin opposite to the anal, which commences behind the
vent. Pectoral fins long, ventrals narrow, inserted high upon the side of the trunk.
No luminous organs (?),

BathopMlus nigerrimus.

BatliopMlus nigerrimus, Giglioli, loc. cit, c. fig.

D. 14. A. 13. P. 29. V. 11.
Known from a single specimen only, found at Messina, 2f inches long.

Idiacanthus,

Idiacanthus, Peters, Monatsber. d. k. preuss. Acad. d. Wiss. Berlin, 1876, p. 846.
BathyopMs, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 181.

Body extremely narrow and elongate, snake-like, naked. Vent far behind the middle
of the length of the body. Head large, compressed, with the snout of moderate length,
and vdih the cleft of the mouth as long as the head. Teeth in the jaws extremely large,
numerous, of unequal size, dejjressible. Similar teeth on the tongue and on each side of
the vomer and palatines. Eye rather small. Opercular portion of the head narrow.
A long barbel anteriorly on the hyoid. The dorsal commences above or in front of the
ventrals and extends nearly to the caudal ; the anal is also long, commencing behind the
vent. Pectorals none. Ventrals inserted in front of the middle of the length of the body.
A small phosphorescent organ above the middle of the upper jaw, and series of small
luminous dots along each side of the abdomen and along the outer ventral ray. Similar
organs on the tail. Gill-opening extremely wide ; branchiostegals short, numerous.
Gills four ; no pseudobranchise.

Idiacanthus fasciola.

Idiacanthtis fasciola, Peters, loc. cit., p. 847.

B. 18. D. ca. 70. A. 41. V. 6. C. | 13 | .

Vent situated anterior to the seventh twelfth of the total lengtli. Commencement of
the dorsal fin rather nearer to the head than to the ventrals. Black.

216 THE VOYAGE OF H.M.S. CHALLENGER,

Known from two specimens in the Berlin Museum ; the larger, about 5 inches
long, was obtained north of Australia in long. 117° E., the smaller, 2 inches long,
north of New Guinea in lat. 1° 4', long. 136° E., both at the surface.

Idiacantlms ferox (PL LII. fig. D).

Bathyophis ferox, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 18L
D. 60. A. 45. V. 6. Vert. ca. 69.

Vent situated at the sixth eighth of the total length. Commencement of the dorsal
fin opposite to the root of the ventrals. Black.

Habitat. — Middle of North Atlantic, Station 63 ; depth, 2750 fathoms. One
specimen, 8 inches long.

The body of this extraordinary form is extremely elongate, band-shaped, with the
muscular system so little developed, that in its present preserved state the vertebral
column appears to be merely covered by the skin, with the outlines of the vertebrae
clearly visible. It is one of those deep-sea fishes in which the stomach and the walls of
the abdomen are caf>able of extreme distention, to receive the prey which the fish is able
to seize, and to hold with its large and formidably armed jaws. The vent lies at the
commencement of the sixth eighth of the total length, the tail being therefore rather
short.

The head is high, compressed, the large jaws forming nearly one-half of its lateral
area ; its length is contained thrice and two-thirds in its distance from the ventral fins,
or is one-fourteenth of the total length. Eye rather small, not quite twice as distant
from the posterior end of the head as from the anterior. Cleft of the mouth extremely
wide, extending backwards to the end of the head, slightly obhque, with the .lower jaw
prominent. The dentition is more complete on the right side than on the left, and
consists in the upper jaw of seventeen long and pointed teeth, of which the fourth and
the eighth are the longest. The teeth of the lower jaw are stUl longer, twenty on each
side, the fourth and eleventh being very long, whilst the hindmost are very short.

These teeth when erect prevent the jaws from shutting, but all of them can be
depressed to the level of the jaws. Vomer with one or two small teeth on each side,
placed at considerable distance from each other ; palatine with a series of three or four
small teeth, slightly increasing in length backwards ; tongue with three pairs of teeth.
GUI-opening very wide, with a very narrow and membranaceous gill-cover. Barbel long,
about twice as long as the head, with the terminal portion slightly dilated by a narrow
fold running along each side, but the end of the appendage tapers again into a dehcate
filament (fig. d).

The dorsal fin commences opposite to the ventrals, and is composed of widely set,

EEPORT ON THE DEEP-SEA FISHES. 217

extremely fine and partly free, simple rays, their number corresponding to that of the
vertebrae ; each ray starts behind a minute curved spine-like projection of the vertebra
(see fig. d'). Anal fin of similar structure, commencing immediately behind the vent,
and terminating, like the dorsal, at a short distance from the caudal. Caudal fin very
narrow and apparently forked. Ventral fins very narrow, pointed, not quite so long as
the head, composed of six very feeble rays ; then- root is about midway between the
vent and the head.

A phosphorescent eye-like organ is situated behind the eye, above the middle of the
upper jaw. Similar but smaller organs are disposed along the lower side of the abdomen
in a double series, which becomes single behind the ventral fins, and is continued on the
tail. About twenty -three may be counted in a series in front of the ventral fins, and
seventeen between the ventrals and the vent ; those on the tail become very inconspicuous
behind. Another series of minute organs occupies the base of the branchiostegals.

Colour entii'ely black ; the lateral folds of the dilated portion of the barbel
white.

The number of vertebraj appears to be twenty-two in front of the ventrals, seventeen
between the ventrals and the vent, and thirty in the tail.

Family Salmonid^.

Argentina, Art.

The three Atlantic species known are very similar to each other in their organisation,
and, therefore, we may infer that they agree very much in their habits. They live at a
considerable depth, but probably at some distance from the bottom, as they have never
been captured by the dredge or trawl during any of the deeprsea expeditions.

Argentina silus, Cuv.

Argentina silus, Collett, Norg. Fisk., p. 173; Nyt Mag. f. Naturvid., vol. xviii., 1884, p. 109.
Argentina syrtemium, Goodo and Bean, Proc. U.S, Nat. Mus., vol. i., 1879, p. 261.

Known chiefly from specimens obtained ofi" the coast of Norway ; Collett reports its
occurrence at 80 and 100 fathoms. The specimen described as Argentina syrtensium
was taken from the stomach of a Phycis hooked on a line that had been set in 200 fathoms
on Sable Island Bank, off" the coast of Nova Scotia.

(ZOOL. CHALL, EXP. — PAKT LVII. — 1887.) Lll 28

218 THE VOYAGE OF H.M.S. CHALLENGER.

Argentina sphyriena, L.

Osmerus hebridicus, Yarrell.

Argentina sphyrxna, CoDett, Norg. Fisk.', p. 171; Forhandl. Vidensk. Selsk. Christ., 1880, p. 92.

Argentina decagon, Clarke, Trans. New ZeaL Inst., vol. xi., 1879, p. 295.

Known jBrom tlie Mediterranean as well as the North Atlantic ; and not rarely found
in deep water on the Norwegian coast. CoUett, who showed that the Osmerus
hebridicus should not be separated from this species, gives 200 fathoms as the depth at
which specimens were secured, and they were taken from the stomach of a Molva
vulgans.

This species seems to occur also on the coast of New Zealand ; at least, I am unable
to distinguish from it the Argentina decagon of Clarke, described from a specimen found
at Hokitika.

Argentina lioglossa, Cuv. Val.

From the Mediterranean. This fish has not been found again since the discovery of
the typical specimens.

Argentina elongata (PI. LV. fig. B).

Argentina elongata, Hutton, Ann. and Mag. Nat. Hist., 1879, vol. iii. p. 53.

This Antarctic species is known from a single young example only, not in a good state
of preservation, 3^ inches long, and obtained at Port Campbell, New Zealand. It is
evidently distinct from the Atlantic species, and characterised by a narrow and prolonged
head.

D. 10. A. 11. P. 15. V. 12. L. lat. ca. 50.

Head and body low, shghtly compressed ; the length of the former is contained thrice
and one-fifth in the total (without caudal), the depth of the body eight times. The
diameter of the eye is scarcely more than one-fourth of the length of the head, and much
shorter than the long and pointed snout. Tongue with a series of curved teeth on each
side. The origin of the dorsal fin is somewhat nearer to the end of the snout than to the
root of the caudal ; ventrals opposite to the last dorsal rays. Scales without denticulations
(only a few on the tail are preserved). Body with a silvery longitudinal band.

Microstoma, Cuv.

The evidence as to the bathybial habits of these small fishes is merely circumstantial.
They seem to have the same vertical range as Argentina, but are much more rarely

REPORT ON THE DEEP-SEA FISHES. 219

seen in collections, as the small size of their slender cylindrical l>ody renders their capture
very difficult. The majority of the specimens come from the Mediterranean {Microstoma
rotundatum, Eisso), and a somewhat allied form has been observed in the Greenland sea
(Microstoma groenlandicum, Rnhrdt,).

Bathylagus.
Bathylagus, Giintli., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 248.

Body oblong, compressed, covered with thin deciduous scales of moderate size. No
phosphorescent organs. Head short, rather compressed, with thin membranaceous bones.
Mouth very narrow, transverse, anterior. The margin of the upper jaw is formed by the
intermaxillary and maxillary, which is very short, dilated. Teeth in the intermaxillary
rudimentary; those of the lower jaw extremely small, implanted on the edge of the bone,
forming a minute serrature ; a series of minute teeth across the vomer and along the
palatine. Eye very large. Pectoral and ventral fins developed, the latter eight-rayed,
and inserted opposite to the dorsal, at a considerable distance from the pectoral. Dorsal
fin in the middle of the length of the body ; adipose fin small, not very far from the
caudal. Anal fin of moderate length or many-rayed. Gill-opening narrowed, commencing
opposite to the root of the pectoral, and extending across the isthmus, the gill-membranes
being united and not attached to the isthmus. Gill-rakers lanceolate, rather long ; gills
small ; pseudobranchise well developed.

The nearest ally to this genus is Microstoma. The thinness of the bones, the
fragility of the fin-rays, the delicacy of the skin and scales, and the enormously large
eyes, seem to be sufficient evidence that these fishes are actually inhabitants of very
great depths, although there may be reasonable doubts as regards the exact depth at
which Bathylagus atlanticus was obtained. These fishes must therefore be entirely
dependent for vision on the phosphorescent light which is produced by other abyssal
creatures. Not being fish of prey themselves, or only to a slight degree, they would be
attracted by the light issuing from the Pediculates and Stomiatids of the deep, and thus
fall an easy prey to these fishes.

Bathylagus atlanticus.

Bathylagus atlanticus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 248.

B. 3. D. 9. A. 13. P 7. V. 8. L. lat. 40.

The height of the body is a little less than the length of the head, which is one-fourth
of the total (without caudal) ; the eye one-half of the length of the head. The width of

220 THE VOYAGE OF H.M.S. CHALLENGER.

the interorbital space is only two-thirds of that of the eye. Snout very short with steep
anterior profile and transverse anterior mouth, the cleft of the mouth being nearly on the
same level as the lower margin of the eye. All the bones of the head are very thin,
semicartilaginous ; the head seems to have been scaleless. The gill-cavity is closed
behind, the gill-opening beginning opposite to the root of the pectoral fin, and the
o-ill-membrane forming a broad bridge across the isthmus. This membranous bridge is
not attached to the isthmus, and contains a layer of transverse muscular fascicles by
which the gill-covers can be simultaneously firmly closed. The branchiostegals are
extremely thin and short and hidden in the membrane. The dorsal fin commences
nearly midway between snout and caudal ; it is short and composed of feeble rays.
Vent placed far backwards, the length of the tail not being much more than that of the
head. Anal fin likewise composed of feeble rays, terminating at a short distance from
the caudal. (The caudal fin is too much injured to ascertain its shape.) Pectoral fin
narrow, close to the lower profile. Ventrals opposite to the hind part of the dorsal fin.

All the scales being lost, their size and number can be given only approximately from
the remaining scale pouches ; they must have been very thin, and the lateral line seems
to have run along the middle of the side of the body.

Also of the colour nothing can be stated, except that the scale pouches have a
distinct black margin.

Habitat. — One specimen, in very bad condition and &\ inches long, was obtained in
the South Atlantic, at Station 318 (depth, 2040 fathoms).

Mr. Murray ^ has made a very important observation on the circumstances attending
the capture of this fish, which has a direct bearing on the question as to the bathybial
range of many of the fishes captured by the deep-sea trawl. At this station the trawl
was over the side for seven hours, but it never seemed to touch the bottom. Yet it
contained, beside the specimen of Bathylagus, several large Medusee, several bright scarlet
Shrimps, and Other animals. "It is impossible to say how near the trawl may have been
to the bottom, but Mr. Murray considers it quite certain that most, if not all, of the
animals above mentioned were captured in the intermediate water, between a depth of
100 fathoms from the surface, and a short distance from the bottom."

Bathylagus antarcticus.

Batlnjlagus antarcticus, Giinth., Ann. and. Mag. Nat. Hist., 1878, vol. ii. p. 248.

D. 10. A. 22. P. 9. V. 8.

This species is closely allied to the preceding, but readily distinguished by the greater
number of anal rays. The height of the body is rather less than the length of the head,

1 Narr. Chall. Exp., vol. i. p. 903.

REPORT ON THE DEEP-SEA FISHES. 221

which is nearly two-ninths of the total length, without caudal ; eye one-half of the length
of the head ; interorbital space flat, about two-thirds as wide as the eye ; snout short,
with rather oblique upper profile. Mouth narrow, hardly lateral, its cleft being above
the level of the lower margin of the eye. Gill-opening as in Bathylagus atlanticus, but
the branchiostegal membrane is not so muscular across the isthmus as in that species.
The origin of the dorsal fin is nearer to the end of the snout than to the end of the caudal
fin. All the fins are composed of feeble rays. The vent is situated at the beginning
of the posterior third of the total length and the anal commences immediately behind
it. Pectorals rather narrow, close to the lower profile. Ventrals opposite to the middle
of the dorsal fin.

Otherwise the. specimen is so much damaged, that I can only add that its scales and
coloration seem to have been very much the same as in the Atlantic species ; and that it
is altogether a rather more slender fish.

Habitat. — One specimen, 4^ inches long, was obtained in the Antarctic Ocean,
Station 157, at a depth of 1950 fathoms.

Family Raih y thrissid.e.

Body oblong, with rounded abdomen, covered with cycloid scales ; head naked ;
bjarbels none. Margin of the upper jaw formed by the intermaxillaries mesiaUy, and by
the maxillaries laterally. Opercular apparatus complete. Adipose fin absent ; dorsal fin
much elongate, many-rayed ; anal fin short. Stomach with a blind sac ; pyloric append-
ages numerous. Gillr apparatus well-developed ; pseudobranchi^ ; gill-openings wide ]J
an air-bladder. Ova very small ; ovaries without duet.

The fish for which I propose this new family differs from the Clupeidfe and allied
forms chiefly in the development of the dorsal fin.

Bathythrissa.

Bathytlirissa, Giinth. Ann. and Mag. Nat. Hist., vol. xx., 1877, p. 443.
Pterothrissus, Hilgendorf, Act. Soc. Leop. Carol., xiii. p. 127.'

Body covered with scales of moderate size ; head narrow, oblong, with the muciferous
channels much developed. Eye large. Mouth narrow, Coregonoid, with liands of minute

' Dr. Hilgendorf .seems to claim priority for the name proposed by him. To this I must demur, until he brings
forward more satisfactory evidence as to the date of publiaition of the sheet of the Leopoldina, which contiiins his first
notice of this fish. That sheet, indeed, bears " August " on the first page (p. 113), but as the Manuscript of it was finished
only on the 31st of that month (see p. 128), it is evident that it could not have been printed, much less published in that
month. Neither the German nor the English reporters on the ichthyological literature of the year 1877 mention Dr.
HilgendorPs paper, which would hardly have escaped their notice if that part of the Leopoldina had been actually
issued. The exact date of the publication of Bathythrissa is November 1.

222 THE VOYAGE OF H.M.S. CHALLENGER.

teeth imbedded in the thick lips ; maxillary with a marginal row of very small teeth.
Caudal fin forked, with a dense layer of small scales. Air-bladder with very thick walls,l
terminating in two short horns in front, pointed behind. • — I

Bathythrissa dorsalis (PI. LVI. fig. A).

Bathythrissa dorsalis, Giinth., loc. cit.

Fterothrissus gissu, Hilgendorf, loc. cit.; Sitzungsb. naturf. Freunde Berlin, 1878, p. 156.

B. 6. D. 56. A. 12. V. 9. L. lat. 112. L. transv. xV Ccec. pylor. 14.

The general aspect of this remarkable fish is that of a much elongated Coregonus, its
greatest depth being one-fifth of the length of the body (without caudal). The head is
low, elongate, one-fourth of that length ; the large eye, the diameter of which is rather
more than one-fourth of the length of the head, occupies nearly the middle of its length,
slightly encroaching upon the upper profile. The width of the bony interorbital space is
much less than the diameter of the eye. Snout projecting beyond the mouth as in
Coregonus ; mouth laterally extending to below the anterior nostril ; the labial fold of the
mandible does not extend across the symphysis. Nostrils close together, separated by a
membrane only. The muciferous channel of the infraorbital is longitudinally divided by
a straight ridge ; angle of the praeoperculum somewhat produced backwards ; operculum
small ; sub- and inter-operculum narrow.

Scales very regularly arranged ; lateral line straight, running along the middle of the
taU.

The vent is situated far backwards, its distance from the caudal being less than the
length of the head.

The dorsal fin is low, but the anterior rays are somewhat the longest ; it commences
above the middle of the pectoral, and terminates above the middle of the anal. Also the
anal rays are short, the anterior being the longest. The caudal fin is deeply forked,
densely covered with scales. The pectorals are more and the ventrals less than half as
long as the head. Ventrals inserted midway between the anal and the head.

Upper parts brownish, shining silvery, lower parts silvery, minutely dotted with brown.

Habitat. — Off" Inosima ; purchased from Japanese fishermen ; depth, (1) 345 fathoms.
One specimen, 15 inches long.

Family AlepocbphaliD/E.

Alepocephahis, Eisso.

All the four or five species of this genus which have been described hitherto, are
bathybial.

REPORT ON THE DEEP-SEA FISHES. 223

Alepocephalus rostratus.

AlepocephoUus rostratus, Risso, Mem. Acad. Sci. Torin., xxv., 1820, p. 291, pL x. fi". 4.
)> „ Cuv. Val., vol. xix. p. ] 72, pi. dlxvi.

„ „ Giinth., Fish., vol. vii. p. 477.

» » Gegenbaur, Morphol. Jahrb., iv., Suppl., p. 1, pis. i.-ii. (skull).

B. 6. D. 16-17. A. 18-19. P. 13. V. 8. L. lat. 55. Ccec. pyl. 12.

The height of the body is a little more than one-fifth of the total length (without
caudal) ; the length of the head a little less than one-third. Diameter of the eye
contained thrice and one-fourth in the length of the head, and longer than the snout.
Scales much longer than wide, with the anterior (radical) margin truncated. Origin
of the dorsal fin opposite to the vent. Pectoral fin longer than orljit. Distance of
ventral fin from the head three-fifths the length of the latter. Uniform deep black.

Habitat. — Mediterranean.

Alepocephalus agassizii.

Alepocephalus agassizii, Goode and Bean, Bull. Mus. Comp. ZooL, vol. x., 1883, p. 218.
D. 15. A. 17. P. 11. V. 6 (?). L. lat. 90. L. transv. 10 | 12.

The height of the body is one-fifth of the total length (without caudal) ; the length
of the head one-third. Diameter of the eye two-sevenths of the length of the head, and
exceeding that of the snout, which is conically elongate, with the lower jaw slightly
produced. Teeth on the intermaxillaries, mandible and palatines. Scales apparently
ovate-lanceolate, parchment-like. Origin of the dorsal fin immediately above the vent,
that of the anal under the second dorsal ray. Pectoral as long as orbit. Distance of
ventral fin from the snout considerably less than twice the length of the head. Colour
dark, head and fins nearly black.

Habitat. — A specimen, lOj inches long, was found by the U.S. steamer " Blake,"
in 922 fathoms in the Central Atlantic ; lat. 38° 19' N., long. 73° 18' W.

Alepocephalus productus.

Alepocephalus produdus, Gill, Proc. U.S. Nat. Mus., vol. vi., 1884, p. 256.

A specimen of an Aleioocephahis from 1362 fathoms in the Central Atlantic
(lat. 39° 26' N., long. 70° W.) is characterised thus : — " Agrees closely with Alepo-
cephalus agassizii, but the eye is considerably smaller, its diameter equalling less
than a quarter of the head's length, while the snout is half as long again as in Alepo-
cephalus agassizii, and forms little less than a third of the length of the head." The size
is not stated.

224 ■ THE VOYAGE OF H.M.S. CHALLENGER.

Alepocephalus hairdii.

Alepoceplialus hairdi, Goode and Bean, Proc. U.S. Nat. Mus., vol. ii., 1880, p. 55.
B. 6. D. 22. A. 25. P. 12. V. 10. L. lat. 65. L. transv. 7 | 12. Ccee. pyl. 15.

The height of the body is contained five and one-third times in the total length (without
caudal) ; the length of the head four times and one-third. Snout equal to the width of
the orliit, which is one-fourth of the length of the head. Snout sub-conical, with the
lower jaw included within the upper. Scales large, thin, oblong, triangular at the free
end. Teeth on the intermaxillaries, mandible and palatines. Uniform indigo-blue.

Habitat. — One specimen, 23 inches long, was obtained on the Grand Banks,
Newfoundland, iij 200 fathoms.

Alepocephalus niger (PI. LVI. fig. B).

Alepocephalus niger, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. [x 248.

B. 6. D. 21. A. 27. P. 10. V. 6. L. lat. 140.

Scales small. The length of the head is rather less than one-third of the total
(without caudal) ; snout projecting beyond the mouth. Black.

Habitat. — North of Australia, 75 miles east-south-east of Raine Island, Station 184 ;
depth, 1400 fathoms. One specimen, 13 inches long.

The depth of the body is one-sixth of the total length without caudal ; the length of
the head rather less than one-third. Head scaleless, flat aboA'^e, the least width of the
interorbital space being two-ninths of the length of the head. Eye of moderate size, one-
sixth of the length of the head, and rather more than one-half of that of the snout. The
snout is depressed, broad, the intermaxillary occupying a transverse position with a sharp
upper edge which penetrates through the skin. The side of the mouth is formed by the
maxillary, which extends backwards a little beyond the front margin of the eye.'

Intermaxillary and mandible armed with a single series of small acute teeth ; a
transverse series of similar but smaller teeth stretches across the fore-part of the palate ;
it is interrupted in the middle, opposite to the head of the vomer, which is toothless.

As in Alepoeep)lialus rostratus the bones of the head are very thin and fragile, the
gill-cavity being covered by a membrane, which is supported by radiating bony ridges of
tiie operculum and suboperculum, not unlike the branchiostegals which are included in the
same membrane.

Gills four, the laminae being short in the upper part of each branchial arch and thicker
isolated and vermiform in the lower part. Gill-rakers stout, pointed, rather widely set ;
fourteen on the outer branchial arch.

1 The nasal region is so much injured, that the form of the nostrils cannot be ascertained.

REPORT ON THE DEEP-SEA FISHES. 225

Vent nearly midway between the upper end of the gill-opening and the root of the
caudal fin. The anal fin commences almost immediately behind it in front of the vertical
from the origin of the dorsal. The caudal fin is still more injured than the two other
vertical fins, and therefore nothing can be said about its form, but it is continued along
the upper and lower edges of the caudal peduncle as a broad fold, which extends almost
to the dorsal and anal and contains well-developed rays, the posterior of which are
articulated and branched. Pectoral fin lateral, inserted ojjposite to the lower half of the
gill-opening. Root of the ventral midway between that of the pectoral and the origin of
the anal.

Scales simple, cycloid, considerably longer than deep, deeply implanted in the skin.
The lateral line is straight, running above the middle of the depth of the body, and is
composed of tubiform scales with rather wide mucous openings.

Colour now uniform deep black, but Mr. Murray ^ informs us that " the whole animal
was of a light blue colour, of a deeper tint about the fins and gill-covers."

Form of the stomach siphoual ; pyloric appendages short, wide, four in number.

Bathytroctes,

Bathytrodes, Giinth., Ann. and Map:;. Nat. Hist., 1878, vol. ii. p. 249.

Body rather elongate, compressed, covered with scales of moderate size. Cleft of the
mouth rather wide ; the maxillary extending to below the middle of the large eye. Both
intermaxillary and maxillary armed with a series of minute teeth, as is also the mandible.
Vomer and palatine bones with simdar teeth. No teeth on the tongue. Eye very large.
Dorsal and anal fins moderately long, the former behind the ventrals ; adipose fin absent ;
caudal forked. GUIs very narrow ; pseudobranchise present. Gill-rakers long, lanceolate.
Pyloric appendages in moderate number. Ova rather small.

Bathytroctes macrolepis, n. sp. (PL LVII. fig. B).

B. 7. D. 15. A. 11. -v. 8. L. lat. 42.

The maxillary extends to below the posterior third of the orbit.

Habitat.— North, of Celebes, Station 198 ; depth, 2150 fathoms. One specimen,
9 inches long (without caudal).

The height of the body is two-elevenths of the total length (without caudal), the
length of the head a little more than one-third. Bones of the head extremely thin ;
membranous, especially the opercular bones which, as in AlepocejjJiahis, are enclosed in
the same membrane with the branchiostegals, forming a large fiap extending from the

' Narr. Chall. Exp., vol. i. p. 521.

(ZOOL. COALL. EXP. — PART LVII. — 18S7.) Lll -9

226 THE VOYAGE OF H.M.S, CHALLENGEE.

scapulary to the hyoid region. Head low and elongate, scaleless, broad across the
occipital region, but tapering towards the front. Its upper surface is deeply concave
longitudinally, the leaist width of the interorbital space being about one-half of the
longitudinal diameter of the eye. The eye is very large, longer than deep, rather longer
than the snout, and contained thrice and a quarter in the length of the head. Snout
rather pointed, with the jaws equal in front and with the cleft of the mouth rather wide,
the maxillary extending beyond the centre of the eye. The dentition is feeble ; teeth
small, pointed, of equal size, uniserial. The intermaxillary and the foremost part of the
maxillary are toothless ; vomerine series divided into two groups, each with three teeth.
Palatine series short, consisting of about nine teeth.

Branch iostegals very slender, rod-shaped. The infraorbital ring consists of very
narrow bones hollowed out for the muciferous channel.

Gills four, with very short gill-laminge. Gill-rakers long, lanceolate, rather widely
set, twenty-two on the out6r branchial arch.

Vent nearly midway between the gill-opening and the root of the caudal fin. Origin
of the dorsal somewhat in advance of the vent, its last ray being opposite to the fourth
of the anal fin. Both dorsal and anal rather high in front, their longest rays being equal
in length to the depth of this portion of the body. (The caudal fin is nearly entirely
destroyed.) Pectoral fin lateral, inserted opposite to the lower half of the gill-opening ;
ventrals with broad base, covering the vent, but not extending to the anal ; their base
is midway between the root of the pectoral and the end of the anal, immediately in
advance of the dorsal.

Only a few of the scales have been preserved ; they are simple, cycloid. The lateral
line is straight, running along the middle of the tail, with wide mucous apertures.

Colour, uniform black.

The specimen is not in a sufiiciently good state to be figured entire.

Bathytroctes microlepis (PI. LVII. fig. A).

Baikytroctes microlepis, Giinth., j\nn. and Mag. Nat. Hist., 1878, vol. ii. p. 249.

B. 7. D. 16. A. 17. V. 8. L. lat. ca. 70.

The maxillary extends to below the posterior third of the orbit.
Habitat. — Atlantic, south-east of Cape St Vincent, Station V.; depth, 1090 fathoms.
One specimen, 10 inches long.

The height of the body is contained five times and one-fourth in the total length
(without caudal), the length of the head thrice and three-fifths. Bones of the head thin
as in Bathytroctes macrolepis. Head rather compressed, moderately deep, its depth at
the occiput being two-thirds of its length ; its upper surface is concave, the width of the

REPORT ON THE DEEP-SEA FISHES. 227

interorbital space being one-half of the longitudinal diameter of the eye. Eye very large,
rather longer than deep, one-third of the length of the head and considerably longer than
the snout. Infraorbital ring very narrow, the broad maxillary being separated from the
orbit by a very narrow strip of bone. Snout somewhat wedge-shaped, with the upper
profile declivous, with the jaws equal in front and with the maxillary extending to the
posterior third of the orbit. Dentition feeble ; all the teeth being equally minute and
uniserial ; the intermaxillary and maxillary are toothed throughout their whole extent ;
vomerine series transverse and straight, slightly interrupted in the middle ; palatine series
nearly as long as vomerine series.

Branchiostegals slender, rod-shaped. Gills four ; that of the fourth arch being short
and reduced to a horizontal series of laminae, which is only one-thii-d of the horizontal series
of the outer branchial arch. Gill-laminse very short, especially on the convex portion of
the arches ; gill-rakers long, lanceolate, closely set, 24 4-11 on the outer branchial arch.

Vent considerably nearer to the root of the caudal fin than to the gill-opening, whilst
the origin of the dorsal fin is somewhat nearer to the latter point. Dorsal fin longer
than high, its anterior rays increasing in length to the fifth or sixth ray. Origin of the
anal behind the vertical from the middle of the dorsal fin, which this fin resembles in
shape. Caudal fin deeply emarginate. Pectoral inserted a short way above the lower
profile ; it has a moderately broad base, is three-fifths of the length of the head, and does
not extend to the ventral. Vcntrals close together, scarcely extending to the vent, their
root being midway between the root of the caudal and the anterior margin of the orbit.

Scales deciduous, cycloid, with numerous fine concentric and radiating striae ; there
were probably nine scales in a transverse series between the lateral line and the origin of
the dorsal fin, and twelve between the lateral line and ventral fin. Lateral line straight,
running from the upper end of the gill-opening along the middle of the tail, Mvith rather
narrow mucous apertures.

Colour, uniform black.

Stomach with a short ccecal sac. Thii'teen short pyloric appendages fringe the
intestine behind the pylorus. Intestine short,, scarcely convoluted. The ovaries, which
are laminated and open on their costal surface, contain an immense number of minute
immature eggs, between which a few larger ones of the size of millet seed are embedded.

Bathytroctes rostratus (PL LVIII. fig. B).

Batlujtroetes rostratus, Gunth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 250.
D. 20. A. 17. V. 9. P. 16. L. lat. ca. 100.
The maxillary reaches to below the hind margin of the orbit; intermaxillary
terminating in front in a short projection.

228 THE VOYAGE OF H.M.S. CHALLENGEE.

Habitat. — Off Pernambuco, Station 120 ; depth, 675 fathoms. One specimen, 6|-
inches long.

The height of the body is nearly one-fifth of the total length (without caudal) ; the
length of the head one-third. Bones of the head very thin and very easUy ruptured, like
all the other parts of the body. Head compressed, moderately deep, its depth at the
occiput being three-fifths of its length ; its upper surface longitudinally concave, the
width of the interorbital space being more than one-half of the longitudinal diameter of
the eye. Eye large, a little longer than deep, contained thrice and two-thirds in the
length of the head and equal to that of the snout. Infraorbital ring narrow, the broad
and large maxillary being separated from the orbit by a narrow strip of bone. Snout
wedge-shaped, with a pair of short and flat projections in front, each being formed by
the intermaxillary and toothed at its extremity. The cleft of the mouth is wide, the
maxUlary extending to below the hind margin of the orbit. Dentition very feeble, all
the teeth being minute and uniserial. The intermaxillary and maxillary are toothed
throughout their whole extent ; the teeth of the mandible are particularly minute, and
the series is interrupted close to the symphysis, the S5rmphysial portion being external to
the lateral portion, which is implanted on the upper edge of the bone. The vomerine
teeth are reduced to a pair of very small teeth in the middle of the bone. Palatine teeth
none, or reduced to a single tooth-like projection.

Branchiostegals long, narrow, slender. Gills as in Bathytroctes macrolepis. Gill-
rakers long, lanceolate, closely set, 20 -f- 7 on the outer branchial arch.

Vent nearer to the gill-opening than to the root of the caudal. Origin of the dorsal
fin somewhat in advance of the vent ; it is much longer than high, the length of the
anterior rays increasing to the sixth or seventh ray. Origin of the anal fin below the
anterior half of the dorsal, which it resembles in shape. Caudal fin deeply emarginate.
Pectoral inserted a short way above the lower profile, rather short and broad, about as
long as the eye. Ventrals broad, extending to the vent, their root being rather nearer to
the base of the caudal than to the extremity of the snout.

Scales simple, cycloid, in about twelve longitudinal series above and below the lateral
line, between the dorsal and the ventral fins. Lateral line straight, running from the
upper end of the gill-opening along the middle of the tail, with rather small mucous
apertures.

Colour, uniform black.

A very small pointed osseous projection in front of the clavicular symphysis reminds
us of a similar peculiarity in the following genus, Platytroctes.

REPORT ON THE DEEP-SEA FISHES. 229

Platytroctes.
Platijtrodes, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 249.

Body rather abbreviated, much compressed, and covered with small keeled scales.
Mouth of moderate width; the maxillary, intermaxillary, and mandible armed with a
single series of small teeth. Palate nearly smooth. Eye rather large. The dorsal and
anal fins opposite to each other, on the tail, moderately long. Adipose fin absent.
Caudal forked. Pectoral small. Ventrals none. Each clavicle terminates below in a
long, projecting, acute spine, the two spines coalescent. Gill-opening wide; six branchio-
stegals. Gills vety narrow, pseudobranchise present; gill-rakers long, lanceolate. Pyloric
appendages rudimentary.

Platytroctes apus (PI. LVIII. fig. A).

Platytroctes apus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 249.

D. 18. A. 17. P. 20. L. lat. ca. 100.

The height of the body is more than one-third of the total length (without caudal) ;
the diameter of the eye one-third of the length of the head. The maxillary does not
extend to below the middle of the eye.

Habitat. — Mid- Atlantic, Station 107; depth, 1500 fathoms. One specimen, 5^ inches
long.

The body of this fish is much compressed and deep, but, singularly, the convex
portions on the dorsal and ventral halves are merely a fold of the skin, into which neither
the muscles nor the abdominal organs enter. The greatest depth of the body is at about
the middle of its length, and contained in it twice and three-fourths, not including the
caudal. The head is likewise compressed, of moderate dimensions, two-sevenths of the
length of the body. Head longitudinally concave above, the concavity being bordered
on each side by a perforated muciferous canal, and broadest behind, but tapering to a
point between the nostrils. The bones of the head are rather thin, but less so than in
Bathytroctes. Eye large, one-third of the length of the head, as long as the snout,
and situated immediately below the upper profile. Infraorbital ring incomplete, the
muciferous canal not being prolonged beyond the prseorbital. Mouth rather small, with
the lower jaw projecting when the mouth is open. Maxillary broad, short, extending to
the front margin of the eye. Dentition very feeble ; teeth uniserial, uniformly minute,
occupying the whole extent of the intermaxillary and maxillary, but confined to the front
part of the mandible; only a few rudimentary teeth are visible on the side of the
mandible. Vomer with a minute tooth on each side ; palatines toothless.

Branchiostegals extremely slender, curved. Gills four, the inner one very short ;

230 THE VOYAGE OF H.M.S. CHALLENGER.

gill laminse short, especially on the convex portion of the arches; gill-rakers long,
lanceolate, closely set, 20 + 10 on the outer branchial arch.

The bones of the shoulder-girdle project at the symphysis as two rather long pointed

spikes.

The vent is much nearer to the root of the caudal than to the gill-opening. The
dorsal fin commences immediately above it, the anal behind ; both fins are very similar
in shape and of moderate height. Caudal peduncle more than half as deep as long, its
depth being increased by a fold of the integument between the vertical fins. Caudal
fin rather short and forked. Pectoral fin very short, only half as long as the eye and
directed towards the back.

Scales small, cycloid, each with a longitudinal keel which is not composed of spines
as in Macrurus, but simple as in the keeled scales of a snake ; the striations, instead of
continuously crossing the scale, are interrupted by the raised median line. Head entirely
scaleless. Lateral line straight, running along the middle of the body and tail, and
composed of very small pores.

Brown ; head, pectoral region, the vent and fringes of the caudal peduncle black.

Xenodermichthys.
Xenodemiiclithys, Giintli., Ann. and Mag. Nat. Hist., 1S7S, vol. ii. p. 250.

Body rather elongate, compressed, without true scales. The skin is rather tough,
finely wrinkled longitudinally, with numerous small nodules, regularly arranged, which
possess the structure and probably the function of luminous organs. JMiuute, rudimentary,
scale-like productions are embedded in the skin, especially on the trunk. Mouth very
small, with feeble jaws and rudimentary teeth in the intermaxillary and mandible, arid a
few in the maxillary. Palate toothless. Dorsal and anal fins equal in length. Caudal
forked. Gill-opening wide, but not extending much above the level of the pectoral fins.
Gills well-developed ; pseudobranchiiE. Gill-rakers long.

Xenodermichthys nodulosics (PI. LVIII. fig. C).

Xenodermichthys nodulosus, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 250.
D. 33. A. 33. P. 6. V. 5.

The height of the body is nearly one-seventh of the total length, without caudal ; the
length of the head two-elevenths. Eye of moderate size, its diameter being more than
the width of the interorbital space. Uniform black.

Habitat. —Bouth of Yedo, Station 232; depth, 345 fathoms. One specimen, 8
inches long.

REPORT ON THE DEEP-SEA FISHES. 231

The form of the body of this extremely interesting tj^e is compressed and elongate,
in fact it simulates in some respects the Stomiatid type. The depth of its body is nearly
uniform between the head and vent, and contained six and a half times in the total
length (without caudal) ; the length of the head, which is compressed and much longer
than deep, five times and one-third. The length of the upper surface of the head only
half the length of its side ; snout extremely short and obtuse, with its anterior profile
parabolic. Mouth small, provided with extremely small teeth on the intermaxillary and
on the anterior portion of the mandible. The maxillary is short, broad, very thin, ex-
tending somewhat beyond the anterior margin of the eye. Eye well developed, im-
mediately below the upper profile, wider than the interorbital space, and two-ninths of
the length of the head ; it is much longer than the snout.

The gill-opening is closed above, and begins from opposite the root of the pectoral
fin. Branchiostegals slender, six in number. Four gills, with well-developed laminae ;
gill-rakers rather long, stout, lanceolate, twenty-five on the outer branchial arch. The
opercles and branchiostegals are enveloped in a common thick skin, so as to be
indistinguishable without dissection.

Vent midway between the roots of the caudal and pectoral. The dorsal fin
commences immediately above, and the anal behind the vent ; both fins low, coterminal ;
peduncle of the tail not quite twice as long as deep. The caudal fin is deeply forked,
each lobe produced into a short filament ; the upper and lower rudimentary rays are
numerous and extend forwards for more than one-half of the length of the peduncle.
Pectoral fin inserted low down the sides, with a very narrow base, rather pointed behind,
and three-fifths of the length of the head. The ventral fins are likewise narrow, half as
long as the head and extending to the vent.

The skin is tough and leathery, finely wrinkled longitudinally, with minute scale-like
productions irregularly scattered over the body. The lateral line is a broad continuous
straight canal, which arises close behind the eye and runs along the middle of the body
and tail. Very small raised nodules ^ with whitish centre are distributed over the body.
They are arranged in subquincuncial order, and even extend on to the rays of all the fins
except the caudal. On the head they form series, one series following the infraorbital
ring, two others the lower limb of the prjeoperculum, and the fourth the margin of the
gill-opening. I consider these organs to possess luminous properties.

Fig. c on PL LVIII. represents a piece of skin slightly magnified, with four
luminous nodules and a number of minute scattered scales.

1 Their histological structure will be described in Appendix B.

232 THE VOYAGE OF H.M.S, CHALLENGER.

Family Halosaueid^.

Halosaurus, Johns.

Body elongate, compressed, terminating in an exceedingly long tapering tail ;
abdomen rounded. Snout much projecting beyond the mouth, which is inferior, of
moderate width. Facial bones with large muciferous cavities ; a series of luminous
organs is generally developed in the course of the mucous canal system. Suboperculum
large ; prseoperculum rudimentary ; interoperculum membranous. Eye large. Teeth
in villiform bands in the jaws, on the rudimentary palatines, and pterygoids ; none on
the vomer. A band of hyoid teeth. Dorsal fin short, opposite to the space between
ventrals and vent. Ajial fin exceedingly long, occupying the entire length of the taU ;
no caudal fin. Lateral line running near to the lower profile, and composed of larger
scales which bear the luminous organs. Gill-membranes entirely separate, with numerous
branchiostegals.

Of this family which hitherto was known from a single example only, four species
were discovered by the Challenger, showing that it is widely and abundantly repi'csented
in the deep sea.

The foUowiug observations have been made on a specimen of Halosaurus macrochir.

The oesophagus, the inside of which is longitudinally folded, passes into the short
pear-shaped stomach, which is caecal, rather thin walled, and beset with short villi in its
interior. The pyloric portion of the intestine is provided with a series of ten appendages
which are not longer than the stomach. The intestine is nearly straight but wide, its
mucous membrane being raised in numerous low annular folds which become distinct at
a short distance behind the last pyloric appendage.

The liver embraces the lower part of the oesophagus ; it possesses only one lobe, that
on the left side, which does not extend so far backwards as the stomach.

The air-bladder is nearly destroyed. It is simple, occupying the posterior half of the
abdominal cavity. A thick nacreous stratum intervenes between the thin inner and
outer membranes. At its anterior extremity it is suddenly contracted into a narrow
tapering tube, which ends in a thread-like ligament attached to the dorsal side of the
lower part of the oesophagus. An open communication between the oesophagus and the
air-bladder does not seem to exist. The tube is surrounded by a muscular ring at the
place where it enters the air-bladder, and a thick muscular fascicle starts from this ring
to each side of the body of the bladder, gradually losing itself on its surface.

The ovaries are two bands extending forwards beyond the stomach. They are

REPOET ON THE DEEP-SEA FISHES. 233

transversely laminated on their costal surface, the ova falling into the abdominal cavity.^
Singularly the right ovary is interrupted in the middle, thus consisting of an anterior and
posterior portion which are separated by a space equal in length to one of the portions.
Peritoneum deep black in the anterior part of the abdominal cavity, but gradually losing
the pigmentation behind.

The kidneys are confluent, and occupy the hindmost part of the abdominal cavity ;
their secretion is collected in a wide tube which lies between them and the intestine ; it
contained three large specimens of a Distoma."^

The stomach contained shrimp-like Crustaceans.

After removal of the dermal ossifications and the visceral portions of the skull, the
cranium (PI. LX. figs. 3, 5, 7) proper appears as the much depressed brain-capsule with
the anterior facial part greatly elongate and narrowed. The whole of the upper surface
is flat, horizontal, the sides of the brain-capsule sloping inwards towards the basal median
line. The occipital region is vertical with scarcely any protuberances, but with a low
exoccipital crest. Also the sloping sides are remarkably smooth. The facial portion
terminates in front in a broad, diamond-shaped rostrate {r), composed of a bilamellate
very thin bone which is the main support of the rostral prolongation of the snout.

The primordial cartilage persists as a thin layer in the otic and occipital regions, but
has entirely disappeared in the roof of the brain-capsule and in the sphenotic region ; it
reappears as a thin thread along the front part of the interorbital septum, expands in
front of the orbit in a lateral prseorbital process (fig. 5, c])), is thickest along the narrow
snout, and terminates in a long tapering point which is wedged in between the two
halves of the rostrale (fig. 4, ec).

The bones which cover the primordial cartilage are of extreme thinness, yet firmer
and more elastic than in many other deep-sea fishes. Only the basi-occipital and basal
bones are somewhat thicker than the rest. In the occipital region the basi-occipital
(fig. 8, ho) occupies the greater part of the area, covering also the infero-posterior portion
of the side of the brain-capsule; its conical excavation for the articulation with the
vertebral column is large and deep. A subquadrangular supraoccipital (spo) is wedged in
between the pair of well-formed paroccipitals {pare).

The side of the brain-capsule gives the appearance of continuous cartilage owing to
the thinness and transparency of the superficial ossifications, the largest of which is the
alisphenoid or prootic (figs. 5, 7, po), with the large foramen for the fifth nerve in advance
of its centre. It is joined to the exoccipital {exo) by a faint sutural line ; this lamella

1 In the definition of this family (Fish., vol. vii. p. 482), the ovaries are described as " closed" ; and, indeed, the
appearance of the ovaries of the only specimen then available, which are so much distended by the mature ova that the
lamination has entirely disappeared, seemed to warrant this view, although already Mr. Johnson {Proc. Zool. Soc. Lond.,
1863, p. 408), in the original description of Halosaurus owenii, states that these organs are " uncovered with a sac."

2 Distomum halosauri, Bell, Aim. and Mag. Nat. Hist., 1887.

(zOOL. CHALL. EXP — PART LVII. — 1887.) Lll 30

234 THE VOYAGE OF H.M.S. CHALLENGER.

extends upwards towards the paroccipital, from which it is separated by a linear strip of
cartilage. The articular facet (a) for the hyomandibular extends a long way above the
alisphenoid and exoccipital immediately below the upper edge of the cranium. Finally
a small quadrangular ossification (pt) occupies the postero-lateral corner of the brain-
capsule ; it is so thin that it can be easUy pressed into the ear-cavity ; perhaps Parker's
name 'pterotic may be applied to it.

The base of the skull is occupied, as usual, by the very large basale (6).
The membrane bones on the upper surface oflTer the peculiarity that the parietals
(fig. S,p) are joined by a long median suture, and not separated by a process of the
supra-occipital; they are bordered on each side by a squamosal (sq) oblong in form.
The frontals (/) are large and long, each longitudinally divided by a groove into a median
and supraocular portion. The narrow part of the snout is occupied by a long unpaired
bone, the ethmoidale medium (em), which in front is expanded into a short lateral process
(fig. 4, em'). This process is folded downwards to the lower side of the snout, where it
forms on each side a semicylindrical groove (fig. 6, e) for the reception of a nerve
(olfactory ?) and blood-vessels. The two canals are separated by a narrow bony promin-
ence, on each side of which there is a foramen for the passage of the nerve. There lie
on each side of the median ethmoid two dermal bones, connected with it only by the
intervening skin ; they are two nasalia, of which the posterior (fig. 3, n) is oblong in
shape, and the anterior (an) linear with a very thin lobe in the middle.

The lower side of the snout is covered by the long vomer (figs. 5, 6, v) longitudinally
hollowed out, and bordered in front by a high horse-shoe-shaped ridge which does not
bear any teeth. It is suturally connected with the basale, but touches only partly the
ethmoidale medium, part of the ethmoidal cartilage being unprotected by bone on the
side of the snout.

The terminal rostrale (r) with the termination of the ethmoid cartilage (ec) has been
mentioned above.

The palato-quadrate arch (fig. 2) also represents peculiarities in the absence or
rudimentary condition of some of its component parts.

The hyomandibulare (hm) is a subquadrangular lamella with a deep groove and wide
foramen in its anterior half; its greater portion is cartilage, which, however, is entirely
covered with an ossified superficial stratum. It is joined to the cranium by the whole
length of th6 upper side of the quadrangle ; the angle between the two posterior sides
offers the base for the articulation of the operculum ; the lower angle is slightly produced
downwards, and has the thin styliform cartilaginous symplectic (sy) attached to it. Its
anterior side is partly free, partly suturally connected with the metapterygoid.

The metapterygoid (?7ip) is a fan-Uke bone with the angle of the fan directed back-
wards and overlapping the lower corner of the hyomandibulare ; one half of its convexity
forms a connection with the quadrate, the other half with the entopterygoid (ep).

EEPORT ON THE DEEP-SEA FISHES. 235

The quadrate (q) is similar in shape to the metapterygoid, the handle of the fan being
formed by the condyle for the articulation of the mandible ; it is intercalated between
and forms broad sutures with the pterygoid bones.

Very remarkable is the prgeoperculum {p7-), which is reduced to a short small bone
situated at the lower side of the quadrate bone. The ectopterygoid (ecp) is a long and
slender bone, thin and lamelliform in its posterior half, and subtrihedral anteriorly, the
trihedral portion being cartilaginous. Viewed from the inside of the mouth the greater
part of its surface is covered with minute toothlets and asperities, but the surface of the
trihedral portion is smooth, giving attachment to a small membranous lamella which
is covered with teeth and represents a rudimentary palatine bone (pal). The ectoptery-
goid is articulated to a condyle-like process of the ethmoid cartilage (fig. 3, cq/).

The hyoid arch does not show any noteworthy peculiarity.

The intermaxillary (fig. 1, im) occupies an obliquely transverse position at the lower
side of the rostrum ; its lateral terminal third is in juxtaposition with the maxillary, its
inner portion is somewhat dilated, and not provided with ascending processes ;
consequently it is fixed and not capable of any sliding downward or forward motion.
The maxillary [m) is rather short, sword-shaped, constricted behind its articulatory end,
and proximally terminating in a styliform curved process which leans against the
ethmoid cartilage behind the ethmoid process (em' or e of figs. 4 and 6); its dental margin
is slightly thickened, and its posterior margin crescent-shaped; it bears a lanceolate
single supramaxillary behind.

The mandible (fig. 2) is a very thin bone, rather broad, longitudinally concave
below, and slightly convex on the side. No separate angular can be observed, but the
articular is curved upwards as a small hook behind the joint. The tooth-bearing portion
of the dentary is separated from the upper margin of the articular by a long and wide
slit which is closed by a fibrous membrane. Meckel's cartilage is very thin and
slender.

The dermal and membrane bones on the side of the head (fig. 1) are semimem-
branous. The operculum (o) is thin, subtriangular, with radiating folds ; it is note-
worthy that the cartilaginous substance of its articulatory facet extends a little way in
the dii-ection of the folds. The suboperculum (so) is much ddated, twice the size of the
operculum, striated, with a frayed margin. The interoperculum (io) is small, and
consists of an anterior dilated and posterior styliform portion. The chain of infraorbitals
is quite straight, and extends from the tip of the snout to the hind margin of the sub-
operculum. They are almost membranous, and being reverted along the upper edge,
form the framework of a wide muciferous canal. The anterior which surround the rostrale
are very irregular in shape, and much reduced in size, whilst the hindmost, which overlies
the suboperculum, is merely a skinny lobe lacerated behind.

Externally the segmentation of the vertebral column would appear to be complete ;

236 THE VOYAGE OF H.M.S. CHALLENGER.

however, sections made in various parts show that the notochord is continuous and
persistent, and that the centra of the vertebrae are only very thin rings of bone. The
abdominal vertebrae are short, deeply pitted, sixty in number ; they are provided with
very short zygapophyses, feeble neural spines, and, below, with rudimentary ribs which
can scarcely be distinguished from fibrous ligaments. The caudal vertebrae are very
similar to those of the trunk, and provided with very feeble, needle-like neural and
haemal spines. Those constituting the extremity of the tail are very narrow and elongate,
and consist of a centrum only. The first interneural is a broad lamella with a pair of
diverging ridges, and attached to the neural spines of the thirty-first, thirty-second, and
thii-ty -third vertebrae. Interhaemal spines rather short and feeble.

The scapulary arch (fig. 2) is very simple and weak. The clavicle (cl) is a narrow,
slightly curved, sword-shaped bone, tapering at the symphysis, and terminating in a
short point at its junction with the supraclavicle. It is suspended from the skull by
two supraclavicles, of which the upper (scl) is the shorter, and slightly dilated at its
distal end. The scapula (sc) and coracoid (co) form an extremely thin lamina, subcircular
in shape. The pectoral rays are joined to four minute basalia. A postclavicle is
absent.

The pubic bones are also very weak, consisting of a thin semicartilaginous rod, dilated
inw\ards into a very thin and weak, bony lamella ; their base is swollen for the insertion
of the fin-rays and cartilaginous.

Hcdosaurus owenii.

Halosaurus owenii, Johns., Proc. Zool. Soc. Lond., 1863, p. 406, pi. xxxvi. fig. 2.
„ „ Giintli., Fish., vol. vii. p. 482.

B. 14. D. 11. P. 11. V. 10. L. transv. 14 | 6.

Snout produced ; its praeoral portion being nearly one half of its length. Eye rather
large, the length of its diameter being two-fifths of the postocular portion of the head,
and much more than the width of the interorbital space. The maxillary reaches the
vertical from the front margin of the eye. The length of the head is more than its dis-
tance from the ventral fin, the base of which is entirely in front of, and somewhat remote
from the base of the dorsal. Pectoral fin with narrow base, very long, extending nearly
to the root of the ventral. Scales of the lateral line scarcely larger than the others,
without phosphorescent organs being visible in the only specimen known. Anterior
portion of the dorsal fin covered with small scales ; anal fin scaleless. Brownish, silvery
on the abdomen ; gill-cover blackish.

The typical specimen from Madeu'a, 17^- inches long, is still the only individual
kuown of this species.

REPORT ON THE DEEP-SEA FISHES, 237

Halosaiiriis macrochir (PI, LIX. fig. A).

Halosaurus macrochir, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 251,

)> ,, Goode and Bean, Bull. Mus. Comp. ZocJl., vol. x., 1883, p. 219.

Halosaurus goodei. Gill, Proc. U.S. Nat. Mus., vol. vi., 1881, p. 257.

B. 12. D. 13. V. 10. P. 11-13, L, transv. 14 | 5,

Snout moderately produced, the prsBoral portion forming only one-third of its
length. Eye rather small, one-fourth of the postocular portion of the head and one-
half of the width of the interorbital space. Maxillary reaching to the front margin of
the eye. The length of the head is more than its distance from the root of the ventral,
the origin of which is immediately in front of that of the dorsal. Pectoral fin with
narrow base, very long, extending nearly to the root of the ventral. Scales of the
lateral line larger than the others, more or less hidden in a pouch of black skin, with a
phosphorescent organ at the base of the free portion. These large scales are continued
for some length on the tail and cover the base of the anal fin, which, like the dorsal, is
covered in its basal half with small scales. Uniform black.

Distance of the snout from the mouth.

Distance of the snout from the eye.

Distance of the snout from the root of the pectoral fin.

Distance of the snout from the root of the ventral, .

Distance of the snout from the origin of the dorsal, .

Distance of the snout from the vent,

Total length, .....

Habitat. — Midway between the Cape of Good Hope and Kerguelen Island.
Common in the central parts of the Atlantic, where it was first discovered by the
Challenger, and more recently by the U,S, survey ships, in from 647 to 1730 fathoms.

Ofi" the Strait of Gibraltar, Station V, ; depth, 1090 fathoms. One specimen,
21^ inches long.

Near Marion Island, Station 146 ; depth, 1375 fathoms. Four specimens, 18 to 20'
inches long.

The entii-e head is naked, only the upper portions of the gill-cover and of the cheek
are covered with scales similar to those of the body.

The band of intermaxillary teeth is broader than the maxillary baud. Palatine
teeth in two separate patches, each being of an oval shape, with the pointed end
directed forwards ; pterygoid teeth in a very narrow band which extends far backwards
in the cavity of the mouth ; basibranchials with a long and broad band.

Four well-developed gills. Outer branchial arch with fourteen widely set gill-
rakers, of which the middle ones are slender and as long as the eye, the others becommg
shorter towards the ends of the series.

. .,

5 lines

1 inch

4 „

3 „

1 ..

5 „

6 „

5 ,,

9 „

7 „

n „

21 „

6 „

23l THE VOYAGE OF H.M.S. OHALLENGER.

In this species luminous organs are more developed than in the other species known,
and the evidence that these organs are developed from the muciferous system, at least
in the present genus, seems to me undeniable ; in fact, the principal series of luminous
organs is borne by the scales of the lateral line. It runs along the lower part of the
side, from the giU-opening along a great portion of the base of the anal fin, and is
separated from the ventral fin by a single series of scales only. The scales of this series
are much larger than the others, carrying at the base of their exposed portion a vertical
narrow subovate patch of glandular matter, which is covered by but visible through the
cuticular pouches which entirely envelop the scales. When divested of the soft
surroundings, these scales show a subvertical raised ridge, which divides them into an
anterior and a smaller posterior portion, the gland-like substance being deposited on the
latter.

The arrangement of the cuticular coverings of the lateral line is not easy to understand,
chiefly owing to the lacerated state of the outer covering, the lacerations being most
irregular and partly caused after the capture of the specimens,partly, however, an evidently
normal condition of the living fish. The artist who drew the figure on PL LIX. found it
quite impossible to reproduce this covering so as to give a correct idea of its appearance.

The series of large scales of the lateral line is covered in its entire length by a
broad membrane of deep black colour, which is thicker at certain intervals, and thinner
and more readily torn in the intermediate portions, the thin portions corresponding in
position to the luminous organs. This membrane is fixed along its upper margin to the
nearest longitudinal series of scales, and has numerous but irregular attachments along
its lower margin to the integument protruding between the neighbouring ventral series of
scales. Normally a pair of slits, an upper and a lower one, in the membrane corresponds
to each of the larger scales. Thus, if we imagine the membrane to be quite intact, a
wide canal would exist along the whole series of enlarged scales, the inner wall of
which would be formed by the scales (with their investing thin membrane), the outer
by the membrane ; and the canal would possess two longitudinal series of apertures
and slits, an upper and a lower, through which water would be admitted into its interior
or through which the mucus secreted would be discharged. The function of the luminous
organs would not be impaired by the covering, as it is thin and transparent at regular
intervals.

This normal state of things is preserved in various short portions of the lateral line,
but at intervals the membrane is ruptured or torn across, generally in its thin parts,
between the slits or at some distance from them, leaving a greater or lesser extent of
the interior of the canal, and frequently the luminous organ itself uncovered. The
lacerated floating margins of the membrane are most irregular in shape and direction.

The accompanying woodcut may assist in rendering this structure intelligible ; it
represents diagrammaticaHy a longitudinal section made along the median line of four

EEPORT ON THE DEEP-SEA FISHES. 239

scales; sc are the scales, which overlap each other only to a shght extent, the overlapping
ends being closely adpressed (not apart as shown in the diagram for the sake of clearness).
Each scale possesses a transverse ridge (r), behind which the gland-like white substance
of the luminous organ (I) is lodged. A membrane (^) investing the greater part of
the transverse ridge (r), and extends forwards covering the preceding scale until it

c.

Fig. 7.

arrives at the luminous organ, where it terminates in a free margin closely surrounding
the luminous organ. All these structures form the inner side of the canal (c), its
outer wall being formed by the outer membrane (in), which is irregularly interrupted
at the places marked 1, 2, 3, and 4.

There are twenty-six luminous spots between the gill-opening and the vent, and
about as many behind the vent along the base of the anal fin. In order to show the
arrangement of the luminous organs on the head, it is necessary to remove the
integument which covers the muciferous bones. They then represent the disposition
shown in figs, a' and a". The organs are of the same shape and structure as on the
lateral line, about nine in number in the infraorbital canal. In the continuation of
this canal on the rostral process of the snout, three other pairs of luminous organs are
developed, and visible on the lower side of the rostrum after removal of the skin.

The mandibulary canal contains five luminous organs, and is continued along the
lower portion of the much enlarged suboperculum. A large patch of a white substance,,
which does not differ from that of the luminous organs described, is deposited in this
as well as the other species (with the exception of Halosaurus owenii) in the upper
part of the gill-cavity, between the gills and the upper part of the supraclavicle. When
this substance is detached from the skin, the surface of the latter is seen to be covered
with a great number of minute papiUse.^

Halosaurus mediorosfris, n. sp. (PI. LIX. fig. C).

B. 11. D. 11. V. 8. P. 8. L. transv. 11 | ?.

Allied to Halosaurus macrochir and with the same comparatively short snout, but
with a shorter pectoral fin. The length of the pra3oral portion is not quite one-third

1 An account of the histology of these luminous organs will be found in Appendix B.

240

THE VOYAGE OF H.M.S. CHALLENGER.

1 inch.

2

8

4 „

2

4 „

11

6 „

9

17 „

6

of that of the snout. Eye rather small, one-fourth of the postocular portion of the
head, and two-thirds of the width of the interorbital space. Maxillary reaching to the
front margin of the eye. The length of the head is nearly twice its distance from the
root of the ventral, which is situated almost entirely in advance of the dorsal. Pectoral
fin with very narrow base, extending nearly to the root of the ventral. Nearly all
the scales are lost, but those of and below the lateral line are much larger than the
others, each bearing a luminous organ.

Distance of the snout from the mouth, . . ... 4 lines.

Distance of the snout from the eye,

Distance of the snout from the root of the pectoral fin,

Distance of the snout from the root of the ventral.

Distance of the snout from the origin of the dorsal fin,

Distance of the snout from the vent,

Total length, .....

Habitat. — West of the Philippine Islands, Station 207 ; depth, 700 fathoms. One
specimen, 171 inches long.

The entire head is naked, only the uppermost portion of the giU- cover and the
upper half of the cheek are covered with scales similar to those of the body ; the bones
of the head are very thin, especially the gill-covers, which are nearly membranaceous, the
operculum folded and the other parts striated. The lower half of the side of the head
from the snout to the gill-opening is occupied by two exceedingly wide muciferous
channels, of which one takes its origin on the preeorbital, the other on the mandible.
The nostrils are small openings, close together in front of the eye.

The dentition is very much like that of Halosaurus macrochir, but the pterygoid
band is rather broader. Also the branchial apparatus does not differ from that in the
species named.

The luminous organs are constructed and arranged as in Halosaurus macrochir;
the glandular patch being narrower and much deeper, occupying the whole width of the
scales, and being pointed above and below. These scales are very large, twice the size
of the others and somewhat distantly placed. There are probably no more than
eighteen between the gill-opening and the vent. This species is rather light coloured,
but the deep black of the buccal and branchial cavities shines through the thin integu-
ments ; also the posterior part of the anal fin is black.

...

8| lines

1 inch.

3 „

2 „

7 „

i „

10 „

5 „

8 „

6 „

11 !.

20 „

...

EEPORT ON THE DEEP-SEA FISHES. 241

Halosaurus rostratus (PI. LIX. fig. D).

Halosaurus rostratus, Giintli., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 252.
B. 9. D. 10. V. 9, 10. L. transv. 13 | 6.

The length of the head much exceeds the height of the body. The snout very-
much produced, spatulate, its prseoral portion being more than one-half of its length.
Eye of moderate size, its length being one-third of the postocular portion of the head,
and considerably less than the width of the interorbital space. Maxillary scarcely
reaching the front margin of the eye. The length of the head is a little more than its
distance from the root of the ventral, which is nearly entirely situated before the dorsal.
Nearly all the scales are lost, but some of the lateral line remain ; they are much larger
than the other scales ; and on the tail, where the lateral line approaches the lower
profile, these larger scales fill up all the space between the lateral line and the anal fin.

Distance of tlie snout from the mouth, ,

Distance of the snout from the eye.

Distance of the snout from the root of the pectoral,

Distance of the snout from the root of the ventral.

Distance of the snout from the origin of the dorsal,

Distance of the snout from the vent.

Total length, . . . , ,

Habitat. — Mid-Atlantic, Station 63 ; depth, 2750 fathoms. One specimen,
20 inches long.

Bones of the head very thin ; operculum smooth, covered with a very fine membrane.
The lower part of the side of the head is occupied from the snout to the gill-opening
by two exceedingly wide muciferous channels, of which one takes its origin on the
prseorbital, the other on the mandible, and which open behind at the gill-opening by a
common and very wide aperture. Branchial apparatus as in the other species.

The dentition is very similar to that of Halosaurtts macrochir, but the palatine
patches are crescent-shaped and rather widely separated from the pterygoid band.

The scales of the lateral line are about three times the size of the others, and about
twenty-four in number between the gill-opening and the vent. Each bears a luminous
organ, vertically elongated and rhombic, but not extending to the upper or lower
margins of the scale. Light coloured, the lower part of the head and the gill-cover
black ; abdominal region blackish.

Halosaurus affinis (PI. LIX. fig. B).

Halosaurus afflnis, Giinth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 4-14.
Snout much produced, but less so than in Halosaurus rostratus ; its pr^oral portion
being scarcely one-half of its length. Eye of moderate size, one-third of the postocular

(ZOOL. CHALL. EXP. — PART LVII. — 1887.) L^ 31

10

1 inch.

2 „

4

4 „

6

4 „

9

6 „

10

16 „

6

242 THE VOYAGE OF H.M.S. CHALLENGER.

portion of the head and equal to the width of the interorbital space. Maxillary not
reaching to the front margin of the eye. The length of the head equals its distance
from the root of the ventral, the origin of which is but slightly in advance of that of
the dorsal. Nearly all the scales are lost, only some of the lateral line remain. They
are much larger than the other scales ; and on the tail, where the lateral line approaches
the lower profile, these larger scales are separated from the anal fin by one series of
small scales only. Otherwise, there is the greatest similarity between this species and
Halosaurus rostratus.

Distance of the snout from the mouth, . . ■ ... 5| lines.

Distance of the snout from the eye,

Distance of the snout from the root of the pectoral fin,

Distance of the snout from the root of the ventral, . ■

Distance of the snout from the origin of the dorsal, .

Distance of the snout from the vent, . '

Total length, .....

Habitat.- — South of Japan, Station 235 ; depth, 565 fathoms. Two specimens,
16^ inches long.

This species is so closely allied to the preceding that it would appear to be
sufficient to refer to the following points only : the band of palatine teeth is not broader
than tiaat of the intermaxillary, only slightly separated from that of the other side, and
somewhat distant from the pterygoid teeth. The scales of the lateral line are about
three times the size of the others, and twenty -nine in number between the gill-opening
and the vent. They seem to have been provided with a luminous organ, but it must
have been very thin and much less developed than in the other species, as only traces
of it remain on the few scales which have been preserved.

The body of the fish is light-coloured ; the head, vent, and hind part of the tail
black.

Family Notacanthi.

In placing the Notacanths in the present work between the Halosauridas and
Mursenidse I do not intend to convey the impression that I consider them to be specially
allied to either of these Physostomous families. There is no other type of Acantho-
pterygians by which they would be connected with that order, whilst the truly abdominal
position of their many -rayed ventral fins offers sufficient grounds for removing them to
the Physostomi. On the other hand, there does not seem to be an oj)en communication
between the air-bladder and the oesophagus, at least in Notacanthus sexspinis. As I

REPOET ON THE DEEP-SEA FISHES. 243

already stated in 1861/ these fishes will, no doubt, have to be placed in a distinct order;
but it would be premature to estal^lish this order l^efore its characters can be defined from
a detailed examination of several of the species.

Notacanthus, Bloch.

Body elongate, terminating in a band-like, tapering tail. A dorsal fin is represented
by a series of short spines, entu'ely, or very nearly replacing the soft rays. The whole
of the tail is fringed by an anal fin, the anterior elements of which are transformed
into spines. Ventrals abdominal, with more than five soft rays. Snout protruding
beyond the mouth, which is inferior, shark-like. Palatine bones movable ; armed with
a series of closely-set teeth like the jaws. Shoulder-girdle loosely suspended from the
skull by ligaments. Air-bladder present, without open pneumatic duct. GUIs four ;
pseudobrauchias absent. Ovaries without oviducts.

This genus may be divided thus : —

a. Dorsal spines in small number (six to eleven) ; teeth in the upper jaw
compressed, obliquely triangular : — Notacanthus.

/3. Dorsal spines more than thirty ; teeth in the upper jaw but little compressed,
and erect : — Pohjacantlionotus.^

a. Notacanthus,

Notacanthus sexspinis ((PL LX. figs. 9—15 ; PL LXL fig. A).

Notacanthus sexspinis, Richards, Voy. Ereb. and Ter., Fish., p. 54, pi. xxxii. figs. 4-1 1.
B. 9. D. 6-8 I 1. A. 13-15 I 160. P. 12. V. 7-8. Cajc. pyL 5.

Gill-membranes united across the isthmus, emarginate in the middle. Teeth in
single series, twenty-eight on each intermaxillary. Ventral fins completely united.

The body is compressed, terminating in a band-shaped tapering tail, the length of
which is a little variable. The vent is placed at a distance from the head, equal to one
and two-thirds or twice the length of the latter. Head rather narrow and compressed,
its depth being one-half or less than one-half of its length ; it is produced into an obtusely
pointed snout, supported by the narrow rostral cartUage, on each side of which are sub-
cutaneous cavities, filled with a large quantity of mucus. The eye, which is covered by
a semitransparent skin and lacks an orbital fold, is one-sixth the length of the head, and
occupies a position in the middle of the depth of the head and in the anterior half of
its length. Nostril in front of the upper margin of the eye with two openings, which
are close together, situated in a common depression. The projection of the snout is
1 Fish., vol. iii. p. 544. ^ xhis name was first proposed by Bleeker, thougli on insufficient grounds.

244 THE VOYAGE OF H.M.S. CHALLENGER.

less than two diameters of the eye. The subsemicircular mouth is entirely at its lower
side, the bones of the upper jaw being covered by the general integument which leaves
only the extremity of the maxillary free, without forming labial folds. On the other
hand, the mandible possesses a distinct fold on each side. The end of the inaxillary is
opposite to the middle of the eye.

Each jaw and the palate are armed with a series of small lancet-shaped teeth which
are arranged with beautiful regularity. Those of the upper jaw are twenty-eight
in number on each side, and have their sharp and acute points obliquely directed
outwards. Those of the lower jaw are somewhat smaller, more erect, and twenty -five
in number on each side. The palatine series is parallel to the intermaxillary series,
and consists of fifty-four teeth. This bone is more movable than the upper jaw,
opposed to the mandible, and evidently performs the function of a jaw.

The broad flexible gill-cover with its integument joins that of the other side, forming
a broad bridge across the isthmus, from which it is entirely free. The supporting bones
are so thin that none of them can be distinguished externally under the firm thick
integument. There are four gills, but no pseudobranchia. The gill -rakers are moderately
long, soft, and remote from each other, the anterior arch bearing about eighteen.

Dorsal spines short, distant from each other ; among a series of seven specimens I
count six in one, seven in four, and eight in two ; a minute soft ray is generally visible
behind the last dorsal spine. The anal fin commences immediately behind the vent
and opposite to the space between the second and third dorsal spines (in a specimen
■with seven dorsal spines); the anal spines gradually increase in length behind, the last
beino- two-ninths of the length of the head ; there are thirteen in three examples, fourteen
in three, and fifteen in one. The soft rays are all simple, and about one hundred and
sixty in number ; the extremities of the last are attached to the base of the extremely
narrow caudal fin. The longest are at about the middle of the length of the fin and
two-sevenths of the length of the head. Pectoral composed of twelve rays, of which the
longest are in the upper half of the fin ; its base is narrow and its length half of that of
the head. Ventral fins far back, but not reaching to the vent ; each consists of one
spine and six or seven rays, of which the inner and outer one are simple, the latter being
frequently transformed into a spine ; the other rays are dichotomous. The two ventrals
are broad, close together, and united by the interradial membrane, which stretches across
from one fin to the other. The scales are very thin and small, cycloid, suboval in
shape, and cover almost every part of the body and head. Lateral line well developed,
running a little above the middle of the depth and disappearing about the middle of the
length of the tail.

Colour brown, inside of cavities black. Length, 18 to 20 inches.

Not rare in the deep water ofi" the coasts of South Australia and New Zealand.

REPORT ON THE DEEP-SEA FISHES. 245

The abdominal organs are in all our specimens much decomposed, so that the
following observations only could be made : —

The intestinal tract above the pylorus is distinguished from the remainder by its
deep black colour, which is spread over the interior as well as the exterior surfaces,
and in fact through the whole tissue of the oesophagus and stomach. The cardiac
portion of the oesophagus is beset with rather long villii which are replaced by
longitudinal folds in the stomach. Form of the stomach siphonal. Five pyloric
appendages of moderate length. The remainder of the intestine very little convoluted
and narrow. Liver not divided into lobes. Gall-bladder with rather fii-m walls.

The air-bladder is of an oval shape, and occupies the posterior half of the abdominal
cavity ; anteriorly it is divided into two short cornua. Its peritoneal coating is very
firm ; its proper membrane consists of a thick pearl-coloured substance, the inside of
which is coated with a delicate vascular membrane which can easily be detached from
the pearly portion. In one of the cornua this membrane passes into a pair of thick
muscle-like pads, but the specimen is in too bad a condition to ascertain their nature.
A pneumatic duct can be traced for a short distance from the end of the left comu, but
is soon lost, and does not appear to reach the oesojihagus. The kidneys are confluent
into one short body, the foremost portion of which extends into the abdominal cavity
behind the thick peritoneal covering, whilst the larger portion is situated between the
muscles of the tail.

The osseous framework of this fish is so much wanting in the characteristic
peculiai'ities of bathybial fishes, as to throw serious doubts upon the statement that
this species at least of Notacanthus lives at a great dej^th. The ossifications of the
skuU (PI. LX. figs. 9-15) are very firm, so that the sutures betw^een some of the cranial
bones are obscure or have disappeared altogether. The cranium proper (figs. 10, 11,
12, 14) consists of the short and compressed brain-capsule, which is connected with the
small and narrow facial portion by the extremely narrow frontal and basal bones ;
the orbit being a wide suboval vacuity, bordered in front by a vertical strip of the
ethmoidal cartilage. The upper surface of the brain-capsule is smooth and rather
convex ; the sides slope inwards, with an uneven surface crossed by two subparallel
ridges in the epiotic region, the articular facet for the hyomandibular being below the
lower ridge ; the basis cranii shows a projecting V-like ridge, open behind (fig. 12);
the occipital region (fig. 14) is subvertical, bordered above with a slight ridge, with
a low swelling above the foramen occipitale, and another on each side ; the orbito-
sphenoid region is entirely membranous.

The primordial cartilage has entii-ely disappeared in this part of the skull, and
owing to the obscurity of the sutures the outlines of the following bones only can be
distinguished. The basioccipital (figs. 12, 14, ho) is large, with a rather shallow

246 THE VOYAGE OF H.M.S. CHALLENGER,

articulatory excavation which is enlarged by a smaller depression on each side ; the
suture between this bone and the upper occipital is distinct, but the paroccipitals seem
to have coalesced with the supraoccipital (spo). The latter bone penetrates between, but
does not entirely separate the parietals (p). The bones on the side of the cranium are
coalesced. The basale (figs. 10, 12, b) has a singular shape ; it is dilated into a pair of
lateral wings closing part of the side of the cranium, and separated from the frontal by
the intercalated alisphenoid (po) ; at the base of the skull it forms the pair of strong
ridges already mentioned, convergent anteriorly, where the bone is narrowed into a
styliform slightly curved process which supports the membranous interorbital septum,
and extends forwards to the rostral process. The frontals (figs. 10, 11, /) are very
narrow, especially above the orbit, and taper into fine points in front. The ethmoidale
medium (em) is a narrow long single bone situated above the remains of the ethmoidal
cartilage (ec).

The foremost part of the snout (figs. 10, 15) is formed by a cartilage, the lower
part of which is ossified, whilst the upper projects free as a flexible rostral appendage
(/). The ossified portion (?•) is wedged in between the ascending processes of the
intermaxillary, which are firmly attached to it, so that this latter bone is not capable of
being moved in any direction. It almost entirely excludes the maxillary (m) from the
margin of the jaw. The maxillary is fu-mly tied to the intermaxillary, and therefore
also not capable of free motion ; its distal extremity is bifid, the lower end being bent
downwards beyond the extremity of the intermaxillary, and the upper modified into
an acute spine.

A singular nodule of cartilage (fig. 10, n) which has no direct connection with the
rostral cartilage, and can be moved independently, is lodged in the fibrous tissue filling the
angle between the intermaxillary and basale.

Of the suspensorium the hyomandibulare (fig. 13, km) is the largest bone ; in
fact it is of unusual size, subtriangular, narrowest below, and provided with a raised
strong, obtuse ridge. Three bones are joined to its lower edge, the entopterygoid (cjj),
the symplectic [sy), which is almost entirely cartilaginous, and the stylohyal (st). The
quadrate (q) is narrow, produced to a point in front of and Ijehind the mandibulary
joint, and forming a long suture with the ectopterygoid (ecj)). A rather lai'ge vacuity
exists between the quadrate and entopterygoid.

The ectopterygoid (ecp) extends forwards nearly to the end of the pal ato -pterygoid
arch, has a subvertical position, and is provided above, near its anterior end, with a pair
of small protuberances for the attachment of ligaments and muscles. To its lower edge
are attached rather loosely the palatal bones (paZ) which together form an arch joining
in the median line, and which are armed with a series of teeth like the jaws. There is
no vomer.

The palatal series of teeth is opposed to that of the lower jaw, as in sharks ; and

REPORT ON THE DEEP-SEA FISHES. 247

the entire front part of the palatal arch can be moved in a vertical direction, thus
assuming the function of the immovable upper jaw.

The mandible is short and deep, with a very thin rudiment of Meckehan cai'tilage ;
only a dentary and articulaiy can be distinguished.

The prseoperculum (fig. 9, pr) consists of a narrow vertical, and similar horizontal
limb, both meeting at a right angle. The operculum (o) is membranous, rayed, frayed
on the edge ; the suboperculum (so) of similar structure, narrow ; the interoperculum
(io) smooth and firmer, attached to the lower limb of the prasoperculum.

Infraorbital bones are absent.

The hyoid and branchial arches do not oS'er any noteworthy peculiarity, except that
the nine slender branchiostegals are crowded together on the epihyal and the
cartilaginous end of the ceratohyal, being enclosed in the same membrane as the
operculum and suboperculum.

The scapulary arch (fig. 10) is very simple, and suspended from the cranium by
loose and easUy detached ligaments. The clavicle (cl) is narrow and curved, the single
supracla-^dcle (scl) not much smaller and single. As usual a urohyal (tih) is attached to
the symphysis of the clavicle. The scapula (sc) and coracoid (co) form an extremely
thin lamina, of which a great portion remains cartilaginous. Basalia minute. Post-
clavicle absent.

The centra of the vertebvce are deeply biconcave, perforated in the middle, rather
short and broad, with deeply pitted outer surface, the abdominal surface of those of the
trunk being remarkably flat. The caudal vertebriB, whUst retaining their short longi-
tudinal axis, are more and more compressed towards the end of the tail, and those of
the extremity of the vertebral column are more elongate, and finally become quite
rudimentary.

The articulation of the first vertebra with the skull is not effected merely by a
simple circular concavity, but there is a distinct median osseous projection on the
upper margin of the centrum of the vertebra, whilst the opposite part on its lower
margin recedes further backwards than the lateral portions of the joint.

There are forty-two vertebrae in front of the one which supports the first
interneural, and forty-nine may be reckoned as belonging to the abdominal portion of
the column.

The neural arches of the abdominal vertebroe are broad and solid, terminating in
short and much depressed neural spines. Posteriorly the neural spines become longer,
slender, needle-shaped, and disappear on the rudimentary vertebrae at the extremity
of the column.

The interneural spines are broad lamella?, which assume a very oblique position,
each being provided with a strong longitudinal ridge, at the top of which the dorsal
spine is joined.

248 THE VOYAGE OF H.M.S. CHALLENGER.

The parapophyses of the abdominal vertebrae are short, placed on each side of the
lower surface of the vertebrae, thus enlarging the abdominal surface of the column.
They are lengthened on the first three or four caudal vertebrae, and then those of each
vertebra coalesce at their distal extremities, forming a wide haemal canal which
disappears in the posterior fifth of the length of the tail. The interhaemals of the
anal spines are strong, corresponding in length to the exterior spines ; only the anterior
are somewhat dilated, the remainder being rod-shaped, and graduallj^ passing into the
interhaemals of the anal rays ; with regard to the numbers, the interhaemals correspond
to the anal rays, and the haemals nearly to the interhaemals.

A short separate bone is horizontally intercalated between the distal extremities
of every two interhaemal spines, each taking part in the articulation of an anal spine.

Ribs begin to be developed on the fourth vertebra, being inserted immediately
below the neural arch ; they are extremely slender, and become gradually longer on the
posterior abdominal vertebrae where each coalesces with a floating rib, the ribs thus
having the appearance of consisting of two roots (one being fixed to the vertebra and
the other free), and of a simple distal portion. Of the caudal vertebrae only the
anterior possess ribs.

The pubic is a simple feeble bone, with a transversely swollen, cartilaginous base
for the articulation of the ventral rays ; it is a thin lamella tapering in a fine point in
front, and with a lamellar longitudinal ridge at its ventral surface.

Notacanthus nasus. . f(V<^

Notacanthus nasus, Blocb, Fisch., vol. xii. p. 113, tab. 431. > ^a^/

„ „ Cuvier, vol. viii. p. 467, pi. ccxli. \^*'

„ „ Gairaard, Voy. Isl. et Gronl. Zool. Poiss., pi. xi. ''

„ „ Littken, Vid. Meddel. nat. Foren. Kj0benlia7n, 1878, p. 145.

B. 8 (9?). D. 9-10. A. 13-17 I 116 (ca.). P. 14-16. V. 3 | 6-7.

Gill-openings reaching forwards to below the posterior margin of the orbit.
Intermaxillary teeth compressed with the point directed outwards, forty on each side ;
the mandibulary and palatine teeth smaller, more erect, and anteriorly in a double or
triple series. Ventral fins scarcely united {vix conjunctse, Llitken).

Only a few specimens are known from the deep-sea off the coasts of Southern
Greenland and Iceland.-^

1 In the absence of all information as regards the dentition, and even of the size of the specimen, it is impossible to
form an opinion as to the distinctness of a Notacanthus obtained by the U.S. Fish Commission in the Gulf Stream
(lat. 40°) in 547 fathoms. It is characterised thus : — Notacanthus analis, Gill {Proc. U.S. Nat. Mus., vol. vi., 1884, p. 255) :
D. 11 I 1. A. 18 I 1 " The length of the snout and diameter of the orbit subequal, and greater than the interorbital
area, and the snout projecting about one-third of its own length beyond the mouth."

IVA.

7

REPORT ON THE DEEP-SEA FISHES. • 249

Notacanthus phasganonis.

Notacanthus phasganorus, Goode, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 535.
D. 10. A. 19 I ca. 130. P. 17. V. 2 | 8-9.

Teeth in the upper jaw blunt, acicular, set side by side like the teeth of a comb,
about thirty-two on each side. In the lower jaw they are shorter and more slender and in
double rows. Villiform teeth upon the palatines, in about two series. The height of
the body is contained once and one-fifth in the length of the head, which is contained
twice and one-third in its distance from the vent. Diameter of the eye one-eighth of
the length of the head, and nearly one-half of that of the snout. Ventrals broad, with
peduncle-like bases thickly covered with scales ; closely adjacent, separated by a narrow
groove (Goode).

One specimen, nearly three feet long, was taken from the stomach of a Laemargus
horealis on the Grand Bank of Newfoundland.

Notacanthus honapartii (PI. LXI. fig. C).

Notacanthus honapartii, Risso, Wiegm. Archiv f. Naturgesuh., 1840, p. 376 (not fig.).
„ „ Filippi and Verany, ]\Iem. Ace. Sci. Torino, xviii. p. 190.

D. 8 (-9). A. (15-) 18 I a; (150). C. 3. P. 9. V. 1 | 7. Csec. pyh 5.

The greatest depth of the body is opposite to the ventral fin, and contained twice
and. two-thirds in the distance of the vent from the end of the snout; the length of
the compressed oblong head is contained twice and one-third in the same length.
The snout is thick, swollen, much produced beyond the narrow transverse mouth, which
is opposite to the front margin of the orbit, and quite at the lower side of the head.
Twenty teeth on each side of the upper jaw. The eye is close to the upper profile,
two-thifds of the length of the snout, one-fifth of that of the head, and less than the
width of the interorbital space. Gill-opening of moderate width, the gill-membranes
being confluent in the vertical from the upper end of the gill-opening, and not attached

to the isthmus.

The whole body and head are covered with minute, smooth, imbricate, and adherent

scales.

All the dorsal spines are short, the anterior very short, the second opposite to the
vent. The anal spines commence immediately behind the vent, and increase in length
posteriorly, passing into the flexible rays, which are of varying and indefinite number.
The pectoral is inserted at the usual distance from the giU-opening, and has the base of

moderate width. Ventrals united and extending to the vent.

" Lll 32

(ZOOL. CHALL, EXP. — PAET LVII. — 1887.)

250 THE VOYAGE OF H.M.S. CHALLENGER.

Total length, ....... 290 mm.

Length of the head, ...... 45 „

Depth of the body, . . . . . . 30 „

Length of the tail, . . . . . . 182 ,,

Habitat. — South -Western Coast of South America, Station 310 ; depth, 400
fathoms. One specimen, 11^ inches long.
Mediterranean.

As Kisso correctly states, the number of maxillary (" mandibule," Risso) teeth is
from twenty to twenty-two on each side, that of the mandible (" machoire," Risso)
twenty, and that of the palate twenty -four. The posterior part of the paired fins and
the lower of the anal are black. Cavity of the mouth and gills black. Structure of the
air-bladder as in Notacanthus sexspinis.

Filippi and Verany ' have shown that Risso, in figuring and describing his
Notacanthus honapartii, has confounded two species. The name ought to be retained
for the specimen described, without reference to the figure which itself is evidently very
faulty.

B. Polyacanthonotus.

Notacanthus rissoanus (PI. LXI. fig. B).

Notacanthus rissoanus, FOippi and Verany, Mem. Ace. Sci. Torino, xviii. p. 190.
B. 9. D. 34. A. 54 I ^ (79). C. 6. P. 11. V. 1 | 9.

The greatest depth of the body is opposite the vent, and one-fifth of the distance
of the vent from the end of the snout ; the length of the narrow, long, compressed
head is one-third of the same length. The snout is compressed, pointed, much pi'O-
duCed beyond the narrow mouth, the cleft of which laterally extends to below the
posterior nostril. Each jaw is armed with a series of fixed minute teeth ; a similar
palatine series within the intermaxillary series ; the mandibulary series fits between
the upper two rows. The eye is close to the upper profile, and distant two diameters
from the end of the snout, and four from the extremity of the opercle ; its diameter
exceeds the width of the interorbital space. The gill-opening is wide ; the gill-mem-
branes are supported by very slender branchiostegals, confluent in front, and not
attached to the isthmus.

The whole body and head are covered by minute, smooth, imbricate, and adherent
scales.

All the dorsal spines are short, distant from one another, the first being above the

' Mem. Ace. Sc. Torin., xviii., 1859, p. 188.

REPORT ON THE DEEP-SEA FISHES. 251

root of the pectoral, the last behind the middle of the length of the tail. The anal
spines commence immediately behind the vent, and very gradually and but sHghtly
increase in length behind, passing finally into flexible rays of varying and indefinite
number. The pectoral is inserted at some distance behind the gill-opening, and has a
very narrow base. Ventrals close to, but not extending to the vent, entirely separate.
Colour uniform light brown, blackish about the gills and on the soft anal fin.

Total length, . . . . . . . 396 mm.

Length of head, ... •50

01 • . . . t/-( ,,

Depth of the body, ...... 32

Length of the tail, ...... 236

Habitat. — South of Yedo, Station 237 ; depth, 1875 fathoms. One specimen, 16
inches long.

Mediterranean.

The teeth are minute, those of the upper jaw scarcely different in size or shape
from those of the lower. There are thirty-one on each side of the upper and twenty-
three on each side of the lower jaw ; each half of the palatine series contains twenty-
one teeth. Each ramus of the mandible with a series of pores which is continued on
the prseoperculum. The union of the gill-membranes takes place opposite to the
middle of the distance between orbit and occiput. Orbit without circular fold. Gill-
cavity and peritoneal sac with a thin layer of black pigment.

The air-bladder is much smaller than in Notacanthus sexspinis, occupying a small
portion of the middle of the abdominal cavity ; anteriorly on the left side it is pro-
longed into a narrow cylindi'ical horn about two-thirds of the length of its body ; there
is no open communication between it and the intestinal duct. The ovaries are a pair
of band -like bodies, transversely plaited and without oviduct. The intestine makes
only one convolution ; pyloric appendages are represented by three short diverticula
only. Kidneys confluent into one short body which is situated between the muscles of
the tail behind the vent.

The description by Filippi ami Verany is so short as to leave the identification of
the Japanese with the Mediterranean fish in some uncertainty ; on the other hand, it
applies sufficiently well to our specimen. And as a number of Mediterranean fishes
are identical with Japanese, and as at least one other species of Notacanthus {Nota-
canthus honapartii) shows a wide geographical range, I should not feel justified in
giving a distinct name to the fish described.

252 THE VOYAGE OF H.M.S. CHALLENGER.

Family M u r ^ n i d .e.

Group A n g u i 1 1 i n a, Gthr,

Congromurasna, Kaup.

Congromur^na guttulata, n. sp.

Allied to Congromurasna hahenata, but witli a comparatively longer taU ; the length
of the body being contained once and two-thirds in that of the tail. Eye rather large,
two-thirds of the length of the snout. Lips somewhat swollen, a wide muciferous
cavity being lodged on the side of the snout ; upper jaw projecting beyond the lower.
Anterior nostril at the extremity of the snout, posterior in front of the middle of
the eye ; a wide pore on the margin of the upper lip. Cleft of the mouth extending
to below the middle of the eye ; teeth very small, somewhat unequal in size, forming
extremely narrow bands ; vomer with a few teeth anteriorly. Length of the head
two-thirds of that of the trunk. Dorsal fin rather low, beginning immediately behind
the root of the pectoral fin. Whitish, with a series of extremely minute black dots
above and another below the lateral line.

A single specimen 7| inches long was obtained at Station 173, off the island of
Matuku, Fiji Group, at a depth of 315 fathoms.

Simenchelys.
Simenchehjs, Goode and Bean, Bull. Essex Inst., vol. xi., 1879, p 27. ,

One species only is known.

Simenchelys parasiticus.

Simenchelys parasiticus, Goode and Bean, loc. cit.

„ „ Jordan and Gilbert, Synops. Fish. K Anier., p. 363.

Abundant on the oS'-shore banks, south of Newfoundland (80 to 200 fathoms) ;
individuals have been found burrowing in the flesh of the Halibut.

Group Mursenesocina, Gthr.

Nettastoma, Rafinescpe.
Three species are known.

I

EEPORT ON THE DEEP-SEA FISHES. 253

Nettastoma melamtrum, Eaf.

Not uncommon in the Mediterranean, and most probably descending to depths
similar to those of its congeners.

Nettastoma parviceps (PI. LXIII. fig. A),

Nettastoma parviceps, Guntb., Ann. and Mag. Xat. Hist., 1877, vol. x.x. p. i4G.

Head small, its length being two-fifths of the distance between the gill-opening
and vent (more than one-half in Nettastoma melanurum). Dorsal fin commencing in
advance of the gill-opening. In other respects similar to the Mediterranean species.

Habitat. — South of Yedo, Station 232 ; depth, 345 fathoms. One specimen,
26| inches long.

Nettastoma procerum.

Nettastoma proce)~u,in, Goode and Bean, Bull. Mus. Comp. Zool., vol. .k. 1883, p. 224.

Distinguished by a long filamentous rostral tip, the length of which is equal to
twice the diameter of the eye. Tail twice as long as trunk and head.

Three specimens, from 16 to 26 inches long, were obtained by the U.S. steamer
" Blake," in lat. 33° 35' to 40° 0' N., long. 76° 0' W.; at depths of 178 and 647 fathoms.

Group S y n a p h o b r a n c h i n a, Gthr.
Synaphobranchus, Johns.
SynapJiobranchus pinnatus (PI. LXII. fig. A).

Murxna pinnata, Grouov., Syst. ed. Gray, p. 19.

Sijnaphohmnchus kaupii, Jolmson, Proc. Zool. Soc. Lond., 1862, p. 1G9.

„ 2nnnatus, Giinth., Fish., voL viii. p. 23.

,, „ Goode and Bean, Bull. Essex Inst., vol. xi., 1879, p. 2G ; Bull.

Mus. Comp. Zool., vol. x., 1883, p. 223.

„ affinis, Guuth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 445.

The eye is one-half or a little less than one-half of the length of the snout ; the
length of the body is contained twice or twice and a third in that of the tail. The
dorsal fin commences above or at a very short distance behind the vent. Koot of the
pectoral midway between the extremity of the snout and the vent. Length of the
pectoral fin half that of the head. Scales rudimentary, lanceolate, oblique ; cheeks

254 THE VOYAGE OF H.M.S. CHALLENGER.

scaly. Dorsal and anal fins low, especially the former. The dentition of the jaws
consists in each of a narrow band of villiform teeth, the inside series containing
larger pointed ones. The largest teeth are on the intermaxillary, where they are
grouped together in an oval-shaped patch, longer than broad. At some distance
behind this group the vomerine series of small teeth commences, running backwards
along the median line of the palate. Coloration black or brown.

Habitat. — Madeira ; coasts of the United States (200 to 740 fathoms).

Coast of Brazil, Station 125 ; depth, 1200 fathoms. One specimen, 18 inches long.

South of Japan, Station 235 ; depth, 565 fathoms. Four specimens, 20 to 27
inches long.

Hyalonema ground, off Inosima, Station 232 ; depth, 345 fathoms. Eleven
specimens, 14| to 22 inches long (type of Synaphobranchus affinis).

South of Philippine Islands, Station 214 ; depth, 500 fathoms. Two specimens,
15^ and 21 inches long.

Philippine Islands, Station 210 ; depth, 375 fathoms. One specimen, 13 inches
long.

Synajyltohranchus hathyhius (PI. LXII. fig. B).

Synaphol/ranchug hathyhius, Gunth., Ann. and Mag. Nat. Hist., 1877, vol. xx. p. 44-5.

Mouth and dentition as in Synrq^ihobranchus pinnatus. Eye one-half or two-
thirds of the length of the snout. The length of the body is contained only once and
one-fourth in that of the tail. The dorsal fin commences above or immediately behind
the pectoral, which is only one-third the length of the head. Scales quite rudimentary,
lanceolate, imbedded in the skin ; cheeks naked. Dorsal and anal fins low, especially
the former. Uniformly black.

Habitat. — Middle of North Pacific, Station 246 ; depth, 2050 fathoms. One
specimen, 24^ inches long.

South of Yedo, Station 237 ; depth, 1875 fathoms. Nine specimens, 14 to 22
inches long.

Midway between Cape of Good Hope and Kerguelen Island, Station 146 ; depth,
1375 fathoms. One specimen, 14 inches long (albino).

Synaj)hobranchns infernalis.

HistiohrancJms infernalis, Gill, Proc. U.S. Nat. Mus., vol. vi., 1884, p. 255.

Possibly identical with Synaphobranchus bathybius. " An isolated small patch of
teeth on the vomer, behind that on its head." "The dorsal fin commences Little behind

REPORT ON THE DEEP-SEA FISHES. 255

the root of the pectoral, while the anal arises not much nearer the snout than the end
of the tail. The pectorals are considerably shorter than the snout."

One specimen, the size of which is not stated, was obtained by the U.S. steamer
" Albatross " in the Atlantic ; lat. 38° 30' N., long. 69° 0' W.

Synaphobranchus brevidorsalis, n. sp. (PI. LXIII. fig. C).

Mouth and dentition as in Synaphobranchus pinnatus. Gill-openings in a single
slit, in advance of the pectoral fins. Eye of moderate size, one-half the length of the
pointed snout. The length of the body is less than one-half of that of the tail ; root
of the pectoral fin much nearer to the end of the snout than to the vent. The dorsal
fin commences so far behind the vent, that the distance between its origin from the
vent equals the length of the head. Pectoral of moderate length, two-fifths of the
length of the head. Scales rudimentary, rounded, imbedded in the skin, extending
over the cheeks. Anal higher than dorsal. Dark brown.

Habitat. — North of New Guinea, Station 218 ; depth, 1070 fathoms. One
specimen, 23 inches long.

Hyalonema ground, oflf Japan, Station 232 ; depth, 345 fathoms. One specimen,
17^ inches long.

Group S a c c 0 p h a r y n g i n a, Gthr.
Saccopharynx.

Saccopliarijnx, MitchiU, Ann. Lye. Nat. Hist. New York, vol. i., 1824, p. 82,

„ Giintk, Fish., vol. viii. p. 22.

Ophiognathus, Harwood, Phil. Trans., 1827, p. 277.
Eurypharynx, Vaillant, Comptes rendus, 1882, vol. xcv. p. 1226.
Gastrostonuts, Gill and Eyder, Proc. U.S. Nat. Mus., vol. vi., 1884, p. 271.

Deep-sea eels, characterised as such by a combination of the Mura)noid characters
with a specifically bathybial modification of the osseous and muscular systems, of which
the former is wanting in inorganic matter, whUst the latter is but very feebly developed,
except in the parts which have to perform the function of deglutition. To enable them
to seize upon prey more powerful than themselves, certain organs have undergone a
degree of specialisation, as is observed in bathybial members of other families with a
similar mode of life; the jaws are exceedingly elongate, and the whole gape, the pharynx
and stomach capable of extraordinary distension. The head is of enormous size, with
short cranial portion ; the trunk of moderate extent, with the vent at its end ; the tail

256 THE VOYAGE OF H.M.S. CHALLENGER.

exceedingly elongate, band-shaped, and tapering into a point. Snout very short,
pointed, flexible ; one nostril in front of the small lateral eye.

Maxillary and mandible slender, armed with feeble teeth, in one or two more or less
complete series ; palate toothless. Gill-openings at some distance behind the head,
close together, at the lower part of the side ; branchial arches five ; very short gUls,
extremely small. Dorsal and anal fins low, more or less rudimentary ; pectorals very
small.

The specimens observed are few in number, and to judge from the descriptions,
referable to three species.

Saccopharynx amptiUaceus (PI. LXVI.).

Saecopliarynx sp., Mitchill, Ann. Lye. Nat. Hist. New York, vol. i., 1824, p. 82.
Ophiognath us ampullar eus, Harwood, Phil. Trans., 1827, p. 52, pi. vii.
Saccopharynx flagellum, Cuv.,' R. an., 1829, vol. ii. p. 355.

„ „ Giinth., Fish., vol. viii. p. 22.

„ ampullaceus, Johnson, Ann. and Mag. Nat. Hist., 1862, vol. x. p. 277.

Both jaws are armed with slender, curved, widely-set teeth, irregularly uni- or
bi-serial, their points being directed inwards. The length of the jaws is from one-third
to one-seventh of the length of the body, that is, the distance from the vent to the
extremity of the snout. The dorsal fin commences a long way behind the head, and a
short distance in front of the vent ; like the anal it may or may not reach the end of
the tail, which terminates into an extremely delicate and thin filament. The small
pectoral fin with some thirty very thin rays. Gill-opening an elongate slit. A bluish-
white line runs on the back along each side of the base of the dorsal fin, and a similar
line is sometimes distinct along the anal fin.

Of this species four specimens are known to have been captured : —

1. The fish described by Mitchill in 1824, which was taken in lat. 52° N. and
long. 30° W.; it was discovered afloat in a helpless condition, having swallowed a fish
10 inches long. The body of this specimen was 14 and the tail 58 inches long. It
does not seem to have been preserved.

2. The fish described by Harwood in 1827, which was taken in lat. 62° N. and
long. 57° W.; it was discovered afloat in a helpless condition, "almost worn out by
unavailing eff"orts to gorge a fish of about 7 inches in circumference." This is the
largest of the specimens known, its body having been about 20 and the tail 34 inches
long. It does not seem to have been preserved.

3. The fish described by Johnson in 1862, which was taken ofi" Madeira, under
what circumstances Johnson could not learn, but probably also floating on the surface ;

' Cuvier ascribes this specific name to Mitchill, as he speaks of the " Saccopluxrynx flagellwn de Mitchill," or of the
" Ophiognathus ampullaceus de Harwood."

REPORT ON THE DEEP-SEA FISHES. 257

it had swallowed another deep-sea fish about 9 inches long {Ilalargyrevs johnsonii),the
stomach of which was forced up into the mouth by the distended au'-bladder, showing
how rapidly both fishes must have ascended to the surface. The body of this specimen
is 82 and the tail 23 inches long. It is preserved in the British Museum.

4. A young specimen in the British Museum, the history of which is unknown ; its
body is 3, its tail 8^ inches long. It is much shrivelled, having been preserved for a long
time, but supplies some valuable information on points in which the larger is imperfect.

I first give a detailed description of the Madeiran specimen.

The figure of the fish on PI. LXVI. will give a better idea of its general appearance
than could be supplied by a description ; it represents the specimen with its victim
m situ; when the stomach is empty the abdominal integuments are contracted, yet
protrude as a wrinkled bag, which, however, does not extend beyond the vent.

The whole fish is covered with a thin, jet-black skin, which is easily ruptured. In
a lateral view of the head the sides are nearly vertical, occupied chiefly by the broad
and long mass of muscle, which is situated between the suspensory and palato-pterygoid
bone. This portion of the head extends far backwards and obliquely downwards, and
is bordered below by the slender and slightly curved maxillary. External to the
anterior extremity of the maxillary lies the small eye which is somewhat obscured by
the skin, and situated so that the fish can discern objects approaching from the side,
from the front and from below. In front of the eye there is only the short, triangular,
flexible rostral appendage, which, at least in this specimen, is bent downwards. The
mandible is as slender and sim^ile a bone as the maxillary, and curved in such a
manner that it can be closely fitted to the latter. When the mouth is shut, the
mandibulary forms an acute angle with the suspensory and with its fellow. However,
the joints at the opposite ends of the mandible are so loose, that the fish had the
power of throwing down the lower jaw until " it was almost in a line with the upper";
and even now the two rami of the mandible can be so far drawn apart, as to form a
rio-ht angle at the symphysis. The posterior end of the palato-pterygoid j^rojects free
out of the muscle, and covered with skin only, leans against the maxillarj' at a distance
of half an inch in advance of the mandibulary joint.

Viewed from above, the cranium appears extremely short and broad, slightly convex
longitudinally as well as transversely ; it is broadest vertically above the hind margin
of the eye, where the side of the cranium projects outwards ; its transverse diameter at
this place is half an inch, but little less than the length of the cranial portion to the end
of the rostral appendage. Thick occipital or nuchal muscles are inserted immediately
behind the line between the lateral projections of the skuU, and hide the occipital portion
of the cranium, the backward extent of which cannot be ascertained without dissection.

(ZOOL. CHALL. EXP. — PART LVII. — 1887.) LH 33

258 THE VOYAGE OF H.M.S. CHALLENGER.

Passing to the lower side of the head, we find the space between the mandibulary
rami occupied only by elastic skin, which, when the rami are closely approximated to
each other, projects as a broad fold on the inside of the gape; it is more or less wrinkled
on its inner surface, especially posteriorly, where it passes into the pharynx. Its
inner membrane, backwards to the end of the stomach, is deep black like the outside.
There is no tongue ; if any rudiments of hyoid elements exist, tljey would be displaced
together with the branchial apparatus a long way behind the head.

The " small, sharp, delicate teeth " which Johnson saw in his specimen were rather
loosely attached to the jaw-bones, and have now almost entirely disappeared; and if we
had not his testimony, confirmed by the dentition of another example, the dentition in
the present condition of the specimen might have been described as " granulations " in
the upper jaw, and as almost absent in. the lower. The dentition has been restored in
the figure from the remaining teeth or traces of teeth in the specimen figured, with the
aid of the perfect dentition in our young specimen.

The smaller example in the British Museum shows that the teeth are very
slender, of two sizes, the longest strongly curved, with the point directed towards the
inside of the mouth; the largest is 2^ mm. long; the majority are 2 mm., and the smaller
sized ones only 1 mm. long. Those of the lower jaw are generally smaller than those
of the upper, and so much directed inwards as to be entirely hidden by the fold of the
skin which covers the inside of the jaws. The largest teeth, from ten to twelve in
number in each jaw, are widely set and placed in the same line ; the interspaces
between them are occupied by the smaller teeth, which may be inserted also in the
same line, or somewhat external to it.

This dentition is much too feeble to be capable of injuring or holding any of
those large and powerful fishes which, as we know, are attacked by the species of
Sacmpharynx, therefore they cannot afi'ord the same amount of assistance in over-
powering the prey as the dentition of Omosudis and others, or even of Chiasmodus.
But they are sufficiently strong to enable the Saccopliarynx to fasten itself to and
retain its hold on another fish, which may drag its enemy a long way before its
strength is played out, and before the Saccopharynx commences to draw itself over
its victim similarly to an Actinia which has captured a large fish or crab. There is
not the slightest reason for supposing that the mode of feeding differs in any of the
species of this genus. And so far from its being " probable that they may derive their
food from the water which is received into the pouch, by a process of selection of the
small or minute organisms therein contained," the absence of any kind of straining
apparatus should have afforded a sufiicient caution against such a proposition, even
if no evidence of the actual mode of feeding had been extant.

The trunk terminates with the vent, which is distant eight and a half inches from
the extremity of the snout. It is compressed, and its anterior part which lies between

REPORT ON THE DEEP-SEA FISHES. 259

the lateral suspensory enlargements of the head is rather muscular. But the muscles
become attenuated further behind, forming a thin band on each side of the vertebral
column. A large abdominal bag, formed by the external integuments and the membranes
of the stomach, is suspended from the trunk, and may be so much distended that the
contents of the stomach are clearly visible through the walls of the bag.

The trunk passes into the compressed tail, on which the muscles form only a
very thin layer. Gradually the depth of the tail diminishes, the last five inches being
as thin as a thread, in which at first elongate vertebral centra are still distinguishable,
whilst the last two and a half inches are a simple filament without segmentation.

Fishes with the organs of locomotion so feebly developed, and with a long caudal
appendage which must be an impediment rather than a help in locomotion, may be
justly supposed to be sluggish in their movements, habitually lying on the bottom of
the sea, more or less concealed in the ooze. They patiently wait for the approach of
their prey, the size of which will compensate for the rarity of the occasions on which
a fish comes within their reach.

The rupture of the abdominal sac has afforded an opportunity of examining some
of the vertebrae in the middle of the trunk. The fibrous ligaments connecting the
vertebrae are extremely thin, and as easily ruptured as in a well -macerated skeleton.
The centra of these vertebrae (fig. v) are 5^ mm. long, hour-glass-shajDed, with deep and
spacious concavities which are connected by a very narrow canal. A pair of short, acute
divergent spines start from the neural surface of the most constricted portion of the
centrum ; they project at a right angle from the longitudinal axis of the vertebra. On
the haemal side another pair of spines project, but they are directed backwards, and start
from behind the middle of the vertebra. The caudal vertebrae are shorter, as may be
seen through the skin, and become elongate again towards the narrowest portion of the
tail.

It is difiicult in our specimen to fix the exact position and shape of the gill-openings.
They are longitudinal slits, eight or nine lines long, close together at the lower side of
the abdominal bag, and about one inch behind the angle of the lower jaw. There is
no separate gill-cavity ; a large body passing through the pharynx can be seen through
the gill-opening, which in consequence of the distension of these parts, would be a wide
open aperture. Three of the branchial arches stretch across the gill-opening, and are
more or less visible from the outside ; they are extremely slender, merely thin carti-
laginous rods with an indistinct knee-shaped bend, and with the gill-laminae less
developed than I have seen in any fish. The second branchial arch is hidden below
the skin, and still smaller than the posterior, the first being cpiite rudimentary, without

any gill.

The dorsal and anal fins are in a rudimentary condition. The former commences
in front of the vent, but its anterior rays become visible only by dissection, and with

260 THE VOYAGE OF H.M.S. CHALLENGER.

the aid of a magnifying glass ; tlie longest rays are about the middle of the tail, where
they are about two lines long, free, and extremely delicate ; they disappear at some
distance from the end of the tail. The structure of the anal fin is similar, but the rays
are on the whole longer and somewhat less delicate. The number of these rays is
independent of that of the vertebrae ; two or three may be reckoned to each vertebra.

The pectoral fins are minute, placed immediately behind,, and a little above, the
gill-of)enings ; they have a comparatively broad base and a rounded margin, and are
composed of about thirty closely approximate, very thin rays.

A pair of narrow bluish-white lines commence on the nape and accompanies the
dorsal fin, one on each side, until it disappears on the tail. The base of the fin itself
runs on a whitish median line which is separated from the lines on the side by a deep
black line. Also the anterior part of the anal runs on such a light coloured line, but
the lateral lines are very indistinct.

I cannot see a trace of these lines in our young specimen, which agrees in every
respect with the larger one, except in some unimportant points to be mentioned here-
after.

Taking into consideration certain discrepancies in the descriptions given by Mitchill
and Harwood, Cuvier as well as Johnson suspected that these authors possibly had
distinct species of the same genus before them. However, if no more than due allowance
is made for the difliculty in making out the exact proportions and structure of these
fragile and more or less distorted and injured objects ; for individual variations, such as
the length of the hair-like posterior part of the tail ; for the changes dependent on
growth ; and finally for the imperfect observations which in Mitchill's, and still more in
Harwood's descriptions are manifest,-^ those discrepancies will be taken at their true
value.

1. Cuvier draws attention to Mitchill's statement that the lower jaw of his fish was
toothless. This may have actually been the case, as the teeth are loosely attached to
the jaw and readily come ofi" ; or they may have been overlooked by Mitchill, as in
our larger specimen such teeth as are still preserved, point inwards, and are hidden
under the fold of the skin which runs along the inner margin of the jaw. The
mandibulary teeth are decidedly smaller than those of the upper jaw, as is best seen in
our smaller example which has them fully preserved.

2. The relative length of the jaws and of the body, that is, the distance between
the snout and vent, seems to undergo a change with growth; at least so it would appear

' Even in Mr. Johnson's description an observation occurs wliicli, without the type specimen, might have been
readily misinterpreted and misused. He says : " What is very remarkable about these (gill-) apertures is that, within
the lips of each, the opposite sides are connected by three narrow cutaneous bands, two near the anterior end of the
aperture, and one near the posterior end." These three " cutaneous bands " are the third, fourth, and fifth branchial
arches which are exposed in the gill-opening.

\ ' REPORT ON THE DEEP-SEA FISHES. 261

from the information wLicli is available at present, and which may be tabulated
thus : —

Length of jaws. Length of body. Proportion.

In the smallest specimen, . . . ' 13| lines. 36 lines. nearly 1 : 3.

In Johnson's specimen, .... 2^ inches. 8A inches. nearly 1 : 3J.

In Mitchill's specimen, .... 3 inches. U inches. nearly 1 : 5.

In Harwood's specimen,! _ _ _ 20 inches. about 1 : 7.

3. Mitchill describes the white lines along the dorsal and anal fins, whilst Harwood
says nothing about them. Johnson's specimen, which without any doubt is identical
with Harwood's fish, has the dorsal lines very distinct, and traces of the anal lines
barely visible ; it, therefore, agrees in this singular point with Mitchill's fish.

4. The length of the tail would be naturally subject to great variation, its posterior
I portion being as delicate as the most slender fin-filament ; and specimens in which this

part is mutilated must be as common as those in which it is intact ; probably it is
readily reproduced. For this reason I cannot attach any weight to the various state-
ments with regard to the extent to which the dorsal and anal fins are continued towards
the extremity of the tail. The longest and perhaps the most perfect tail was observed
in Mitchill's specimen, in which it was four times the length of the body, with the
dorsal and anal fins continued to its extremity. In the three other specimens the tail is
respectively only one and a half times, two and a half times, and thrice as long as the
body, and every trace of the dorsal and anal is lost at a greater or lesser distance from
its extremity.

5. Mr. Johnson lays particular stress upon a series of free filaments apparently
starting from the skin of the back, and described by Mitchill as accompanying the
dorsal fin for a considerable distance ; they were about one inch in length and some
fifty in number. These filaments are certainly not to be seen in the Madeiran fish, but
were present in Harwood's specimen, as he mentions them, and some are clearly shown
in his figure. As Mr. Johnson nevertheless justly considers his fish to be identical with
Harwood's, he should not have relied upon this character as indicating the specific dis-
tinctness of his and Mitchill's specimens.

6. All four specimens agree in the dorsal fin commencing at a considerable distance
behind the head, and at a short distance in front of the vent.

These considerations led me some twenty -four years ago to the conclusion that there
is no sufficient evidence of these specimens being representatives of distinct species ;
and as no fresh light has been thrown upon this question by the recent discoveries of
either the French or the North American surveying vessels, I see no reason to abandon
the view then expressed.

1 Harwood does not give the measurements ; the proportion has been ascertained from the figure, allowing for the
I'oreshoilening of the curved jaws.

262 THE VOYAGE OF H.M.S. CHALLENGER.

Saccopharynx pelecanoides.

EurypJiarynx pelecanoides, Vaillant, Comptes rendus, 1882, vol. xcv. p. 1226.^

Both jaws possess merely feeble dental granulations, but the lower jaw is armed in
front with a pair of slender curved teeth (2 mm. long). The length of the jaws is
about one-half of that of the body. The origin of the dorsal fin is nearer to the end
of the snout than to the vent ; neither the dorsal nor the anal fin reach the end of the
tail (which terminates in a small skinny lobe). Gill-opening a very small round
opening. No bluish-white line along the back.

Known from a specimen, 18^ inches long, of which the body takes about 6 inches ;
it was captured during the cruise of the French surveying vessel " Travailleur," on
the coast of Morocco, at a depth of 2300 meters. The tail has much the appearance
of having been mutilated during the life of the fish.^

Saccopharynx hairdii.

Saccopharynx flagellum, Goode and Bean, Bull. Mus. Comp. Zool., vol. x., 1883, p. 223; Proc.

U.S. Nat. Mus., vol. vii., 1885, p. 65.
Gastrostomus bainlii, Gill and Ryder, Proc. U.S. Nat. JIus., vol. vii., 1885, p. 271.

Jaws with minute acute conical teeth, depressed inwards in a very narrow band,
without fangs at the extremity of the lower jaw. The length of the jaws is more than
one-half of that of the body (distance of the snout from the anal fin). The origin of
the dorsal fin is nearer to the end of the snout than to the origin of the anal ; neither
the dorsal nor the anal fin reach the end of the tail. Gill-openings narrow. No
bluish -white line along the back.

This form is based on four specimens obtained by the North American surveying
vessels between lat. 35° and 40° N., and long. 65° and 74° W., at depths of 389, 898,
1309, and 1467 fathoms. One of these specimens is 18^ inches long, of which the
body apparently takes 6^ inches. It is uncertain whether these specimens are
specifically distinct from Saccopharynx pelecanoides ; indeed, Mr. Jordan,^ in referring
to the fishes of this genus says with very good reason " the species are little known
and possibly all forms of a single one."

1 The typical specimen has been figured in a woodcut in " La Nature,^' 1883.

2 Whilst this sheet is passing through the press, we learn from Perrier, Les Explorations Sous- Marines, Paris,
188G, 8™, p. 56, that a second specimen was discovered by the naturalists of the " Talisman " off Mogador. No mention
is made of any differences which may exist between the two specimens.

^ Catalogue of the Fishes known to inhabit the Waters of North America, 1885, p. 57.

REPORT ON THE DEEP-SEA FISHES. 263

Group N e m i c li t h y i u a, Gthr.

Nemichthys, Richards, i
Nemichthys scolopacea.

Nemichthys scolopacea, Eichards, Voy. Samar. Fish., p. 2.5, pi. x. figs. 1-3.

„ ,, Giinth., Fish., p. 21.

„ „ Jordan and Gilbert, Syuops. Fish. N. Amer., p. 366.

„ ,, Goode and Bean, Bull. Mus. Comp. Zocil., vol. x., 1883, p. 225.

Leptorhynchus leuchtcnhergii, Lowe, Mem. Savans liltrang. St. Petersb., vol. vii., 1854, p. 171.
Belonojisis Jeuchtenhergii, Brandt, ibid., p. 174, c. fig.

The dorsal fin commences immediately behind the occiput, and the anal behind the
vent. Vent below the middle of the pectoral fin. The diameter of the eye is two-
fifths, and the greatest depth of the head two-thirds of the length of the postorbital
portion of the head.

The larger of the two specimens in the British Museum, which is probably the
type of Lowe's description, is 33 inches long, and was caught at Madeira. The U.S.
Fish Commission has obtained many specimens by means of the trawl ofi" New England,
in depths of from 304 to 1047 fathoms.

Nemichthys avocetta.

Nemichthys avocetta, Jordan and Gilbert, Proc. U.S. Nat. Mus., vol. iii., 1881, p. 409 ; Synops.
Fish. N. Amer., p. 367.

This species, which is perhaps not specifically distinct from Nemichthys scolopacea,
is characterised thus : — " Head slenderer, its depth one-ninth jts greatest length. Eye
large, one-third the head, without snout. Length of pectoral scarcely greater than
height of anal, which is scarcely less than the greatest depth of the body, and more
than the greatest depth of the head. Translucent ; belly with close-set dark spots, its
lower edge and anal fin black, the back abruptly white and unspotted."

One specimen, 22 inches long, was captured at the surface in Puget's Sound ; its
movements in the water are said to have been extremely active.

' Some fishes obtained by the U.S. Fish Commission, off the coast of New England, belong to this or perhaps an
allied genus, but are, at present, too imperfectly described to deserve more than a passing notice, viz., Sernvovier heanii,
stated to be " the stoutest of the family, and with much shorter jaws than any other, and with a very formidable
vomerine armature"; 21 inches long, from 855 fathoms. Spinivomer goodd, name given to a young specimen 130 mm.
long, from 2361 fathoms. Labichthys carinatus and Labkhthys elongatus, with "tlie tail abruptly truncated," about
16 and 20 inches long, from respectively 906 and 1628 fathoms. Gill, Proc. U.S. Nat. Mus., vol. vi., 1884, pp. 260-262.

264 THE VOYAGE OF H.M.S. CHALLENGER.

Nemichthys infans (PI. LXIII. fig. B).

Nemiclitliys infans, Giinth., Ann. and Mag. Nat. Hist., 1878, voL ii. p. 25L

Body mucli less elongate and eye much smaller than in Nemichthys scolopacea.
Vent twice or thrice as distant from the root of the pectorals as is the latter from the eye.

Habitat. — Mid-Atlantic, Station 101 ; depth, 2500 fixthoms. One specimen,
11 inches long.

Off Pernambuco, Station 121 ; depth, 500 fathoms. One specimen, 7^ inches long.

Besides these two specimens the British Museum has received a third from the
Mona Channel in the West Indies, which was found attached to an old telegraph cable
that had been laid at the depth of 814 fathoms ; it is 14 inches long, but had a great
part of its body mutilated during life. This specimen, which is better preserved than
the two others, will be referred to as specimen C in the following description.

The body, although compressed, is rather fleshy, in its anterior portion lower and
narrower than the head, but becoming broader and wider behind, the terminal portion
tapering again, but retaining a thin muscular covering to the very end (fig. B'"). In
specimen C (which is figured) the body was mutilated during life at a short distance
behind the point where it attained its greatest depth, and the mutilated part is
surrounded by a rather broad fin, in which a number of branched fin-rays have been
developed.

The hind part of the head is subquadrangular, nearly as deep as broad. Eye
without circular fold, of moderate size, its diameter being about one-third of its distance
from the pectoral fin, and about twice the width of the interorbital space. The snout
is produced into the same long slender bill as in Nemichthys scolopacea. The
extremities of the upper and lower jaws terminate in two small swollen knobs (fig. B")
in the two smaller specimens, which are not observable in specimen C. The asperities
with which the beak is armed in its entire length, are in the form of minute imbricate
scale-like denticles, the points of which are directed backwards (fig. B'). The cleft of
the mouth extends a little behind the eye.

The gill-openings are nearly as wide as the orbit, obliquely directed towards the
median line of the belly and rather close together. In specimen C the vent is nearly
three times as distant from the pectoral fin as this latter is from the eye, but the
distance is comparatively less in the two smaller specimens.

The dorsal fin commences immediately behind the pectoral, and is throughout
composed of extremely delicate rays ; of these only the anterior are distinctly connected
by membrane, all the others are free and probably non-erectile. The anal fin
commences immediately behind the vent, and is more developed than the dorsal, its
rays being stronger and longer ; only its anterior rays are delicate and rudimentary

REPORT ON THE DEEP-SEA FISHES. 265

like those of the dorsal fin. Pectoral fin well developed, with broad base, as long as
the body is high, its point being directed upwards. The lateral line runs along the
middle of the side and is composed of conspicuous and rather widely -set pores. It can
be traced to the extremity of the tail.

Coloration black; jaws, pectoral fin, and lower part of the abdomen of a lighter colour.

One of the specimens had in its stomach the remains of two large yhrimps.

The figure of the entire specimen is of the natural size, that of the head twice the
natural size. B' is an enlarged view of a portion of the dentition of the upper jaw ;
B" the end of the upper jaw of one of the small specimens, much magnified ; B'" end
of tail of the same specimen, slightly enlarged.

Cyema.

Cyema, Giintli., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 251.

This genus combines the form of the snout of a Nemichthys with the soft .short
body of a Leptoccphalus ; but the gill-openings are very narrow, and close together on
the abdominal surface. Vent in about the middle of the length of the body ; vertical
fin well developed, confined to and interrupted at the extremity of the tail. Pectoral
fins well developed. Eye very small.

Cyema atrum (PI. LIV. fig. D).

Cyema atrum, Giinth., Ann. and Mag. Nat. Hist., 1878, vol ii. p. 251.
The cleft of the mouth extends backwards to the end of the head. Black.
Habitat. — South Pacific, Station 295 ; depth, 1500 fathoms. One specimen,
4^ inches long.

Antarctic Ocean, Station 158; depth, 1800 fathoms. One specimen, 4§ inches long.

The body is compressed, band-shaped, soft like that of a Leptoccphalus, but, for an
eel, short, its depth being one-twelfth of its length, the head not included ; it is nearly
of uniform depth throughout its length, except close to the end where it gradually
becomes narrower, the end itself being rounded. The postorbital part of the head is
compressed like the body ; in front of the eye, which is minute, the snout tapers into
the very long and slender beak, both jaws being armed \Wth a broad band of asperities
or teeth. The upper jaw shows at about half its length a distinct swelling, in front of
which the jaws coalesce into the tapering simple extremity of the beak; the dentiferous
parts of the jaw diverge behind the swelling, leaving a depression between them in
which a narrow band of asperities runs well backwards along the median line (fig. d).
The asperities are subimbricate and arranged in transverse series (fig. d') ; those of the
median band being rather lanceolate in shape. Cleft of the mouth extending to the
end of the head, the jaws being toothed to their posterior extremity.

(ZOOL. CHALL. EXr. — PART LVII. — 1887.) I^" 3*

366 THE VOYAGE OF H.M.S. CHALLENGEE.

Nostrils, two minute openings in front of the eyes ; gill-openings very small, close
together at the lower surface of the body, immediately in front of the base of the pectoral
but at some distance from the angle of the lower jaw (fig. d").

Vent midway between the angle of the lower jaw and the extremity of the tad ;
the vertical fin is well developed, but does not surround the extremity of the tail,
showing a distinct break between the neural and haemal portions. The dorsal fin
commences opposite to the vent and is composed of numerous closely set delicate but
very distinct rays. The rays are longest on the narrow portion of the tad, but rapidly
decrease in length backwards. The anal is entirely similar to the dorsal as regards
structure and extent. Pectoral well developed, composed of about twelve rays, its
distance from the eye being two-fifths of that from the vent.

Lateral line inconspicuous, running along the middle of the tail.

Coloration uniform black.

This form is extremely interesting, inasmuch as it is still nearer to the
Leptocephalid condition than Nemichthys iiifans. In fact, I had to consider the
possibility of its being a less advanced stage of development of that species ; however,
the minute size of the eye disposes of the idea of genetic affinity. Possibly some of
the long forms of Leptocephalus are the offspring of this and the preceding genus.

PLECTOGNATHI.

The fishes of this order are littoral and a few only pelagic forms ; none show in
any part of theu* organisation special adaptation for a bathybial existence. All are bad
swimmers. It is therefore not improbable that of the following two species, at least
the Monacanthus was caught near to the surface.

Triacanthodes, Blkr.
One species only is known.

Triacanthodes anomalus, Schleg.

Triacanthodes anomalus, GiintL, Report on the Shore Fishes, Zool. Chall. Exp., pt. vi. p. 50.

This species was hitherto known from Japan only. Specimens were obtained at Ki
Island, Station 192, where the trawl brought up a great number of new and interesting-
forms from a depth of 140 fathoms.

Monacanthus, Cuv.

None of the numerous species of this genus, which is spread all over the tropical
and subtropical seas, have ever been recorded from deep water, with the exception of
the following.

REPORT ON THE DEEP-SEA FISHES. 267

Monacanthus tessellatus.

Monacanthus tessellatus, Guntb., Report on the Shore Fishes, Zool. ChaU. Exp., pt. vi. p. 54,

pi. xxiii. fig. B.

One specimen, 5 inches long, was obtained at the PhUippine Islands, Station 204,
where the trawl descended to a depth of 115 fathoms,

CYCLOSTOMATA.
Myxine, L.

The habits and vertical distribution of all the Myxinidaj are probably the same, Init
we possess positive information on these points in the case of two species only.

Myxine glutinosa, L.

The common North Atlantic species is locally abundant at small depths, as, for
instance, in the Norwegian Fjords, at 70 fathoms. . Messrs. Goode and Bean have found
it in the collections made on the Atlantic coast of North America, at depths of from
172 to 524 fathoms.!

Myxine australis (Jenyns).

This species, which is common on the coast of the southern extremity of the
American continent, occurs also in the Japanese Sea, half a dozen specimens from 9 to 20
inches long having been taken on the Hyalonema ground at a depth of 345 fathoms
(Station 232). I also believe that Heptatrema cirrhatum of Schlegel, should be referred
to the same species. The three foremost teeth of the inner series are invariably confluent
at the base, but in adult specimens they are neither longer nor stouter than the next
succeeding. The branchial apertures are subject to some variation, a specimen from
Magellan Strait having two on the left side and one on the right. Also the pores of
the lateral line may be sometimes very distinct, sometimes scarcely conspicuous; and it
appears to me that the smaller foramina represented in Schlegel's figure of Heptatrema
cirrhatum are nothing else but those of the lateral line, which in the specimen figured
were unusually conspicuous, as I have also seen them in specimens from Magellan Strait.

Finally, a Lamprey has also once been obtained at a depth of 547 fathoms in the
Atlantic, lat. 40° 0' N., long. 68° 50' W., and noted as Petromyzon (Bathymyzon)
hairdii, which is said to be distinguished from other Lampreys by the obsolescence of the
cusps of the dental laminse. No indication is given as regards the size of the specimens.-

1 Ball. Mus. Comp. Zool., vol. x., 1883, p. 226 ; and Proc. U.S. Nat. Mus., vol. iii., 1881, p. 486.

2 Gill, Proc. U.S. Nat. Mus., vol. vi., 1884, p. 254.

268 THE VOYAGE OF H.M.S. CHALLENGER.

ADDENDA.

On page 15 add : — Polyprion, Cuv.

Polyiwion cernium, Val.

Polyprion cernium, Lowe, Fish. Madeira, p. 183.

Not rare in the Mediterranean, and the neighbouring parts of the Atlantic. Young
si^ecimens live near the surface, but the largest occur at Madeira in depths of from 300 to
400 fathoms.

On page 41 add : — Thyrsites, C. V.

Thyr sites pretiosus, Cocco.

Aplurus simplex, Lowe, Fish. Madeira, p. 12L

The " Escolar," one of the best food-fishes of Madeira and the West Indies, lives
habitually at moderate depths, and is taken with the line by Madeiran fishermen at a
depth of 300 or 400 fathoms.

Tliyrsites jyTometheus, C. V.

Prometheus atlantieus, Lowe, Fish. Madeira, p. 141.

Not uncommon at moderate depths at Madeu'a and St. Helena; frequently taken at
the former island at depths varying from 100 to 400 fathoms.

On page 49 add : — Notothenia, Eichards.

Notothenia mizops.

Notothenia mizopis, Giinth., Eeport on the Shore Fishes, Zool Chall E.\:p., pt. vi. p. 16,
pi viii. fig. D.

Several specimens, from 1^ to 6 inches long were caught in 120 fathoms off'
Kerguelen Island.

On page 121 add : — Ophidium, Cuv.

Ophidium mursenolepis.

Ophidium murxnolepis, Giinth., Eeport on the Shore Fishes, Zool. Chall. Esp., pt. 6, p. 46,

pi. XX. fig. A.

One specimen, 7 inches long, was obtained at Ki Island, Station 192, in 140
fathoms.

APPENDIX A.

REPORT on the Structure of the Peculiar Organs on the Head of Ipnops. By
Professor H. N. Moseley, F.R.S. (Pis. LXVIL, LXVIIL).

In the General Report on the Scientific Results of the Voyage of H.M.S. Challenger,^
some account is given of the structure of the peculiar organs existing on the head
of Ipnops murrayi. As there stated, Mr. John Murray was the first to examine these
organs by means of sections, and point out their remarkable peculiarities. He concluded
that the organs were organs of luminosity, and Dr. Giinther formed the same opinion
from his examinations of the specimens. Mr. Murray kindly placed his sections at my
disposal ; they did not show any structure very clearly, and being misled by an unlabelled
slide placed with the rest and containing a section of the retina of some ordinary
teleostean fish, and which I attributed to Ipnops, I formed the opinion that the
peculiar organs of that fish were essentially retinal in structure, and hence arrived at the
conclusion that the organs must be regarded as modified organs of vision.

Mr. Murray's preparations not being sufficient for any definite conclusions as to the
structure and relations of the peculiar organs, Dr. Giinther kindly placed a perfect
specimen of Ipnops at my disposal for a detailed examination, and on making a complete
series of sections of the head I found no trace of any retina-like organ and soon realised
my mistake. The peculiar organs have in reality no connection with organs of vision.
The eyes, as well as the optic nerves, are entirely aborted in the fish, and the organs
are apparently not sensory at all, but most probably phosphorescent, as Dr. Giinther
and Mr. Murray at first concluded. I have to express my thanks to Sir Henry Aclaud,
K.C.B., Librarian of the Radcliffe Library, for permitting me to publish the drawing
reproduced on PI. LXVIL by the artist of the Library.

I shall term the organs the phosphorescent organs, for the purposes of description here.
The organs are paired expanses completely symmetrical in outline, placed on either
side of the median line of the upper flattened surface of the head of the fish, and ex-
tending from a line a little posterior to the nasal capsules nearly to a point above the
posterior extremity of the cranial cavity. They are covered by the upper wall of the

1 Narr. Cliall. Exp., vol. i., part i., p. 239.

270 THE VOYAGE OF H.M.S. CHALLENGEE.

skull, which is extremely thin and completely transparent in the region lying over them.
This upper wall consists of membrane and membrane bone, but I was unable to ascertain
the exact extension of the latter, since I had no macerated specimen to refer to and
was obliged to decalcify the one used for sections. Where the bony matter is thinnest it
appears as a more or less open network of very fine spicules embedded in the membrane.
The margins of the phosphorescent organs are extremely clearly defined, because they bear
at their edge a special band of dark pigment (PL LXVIL).

The organs rest in a pair of elongate cavities, one on either side of skull. These
cavities are separated from one another by a longitudinal median septum, which in
their anterior region is composed of a vertical plate of cartilage continuous with a
horizontal plate of cartilage which forms the roof of the mouth cavity. The floors of the
cavities are nearly flat, but owing to the rising in height of the septum and roof of the
skull posteriorly, the cavities there become deeper, and are deepest in the region indicated
by the letter a (PI. LXVIII. fig. 1) immediately on either side of the base of the median
septum. Probably these regions represent the former position of the orbital cavities, and
the septum the interorbital septum, although all trace of eyes has disappeared. The
skull-roof lying immediately over these areas forms a pair of convex cornea-like
prominences (PI. LXVIII. fig. 1, a). Beyond these anteriorly and laterally it is
flattened, and shows concentrically disposed striae {Jhicl., fig. 1, b). On either side
of the median septum the skull-wall is traversed by a long closed canal (fig. 1, J").
These canals are seen in section in fig. 2, and contain organs which in spirit are
opaque, white, apparently mucous canals, and also transmit a nerve on each side to
the nasal capsule, no doubt the nasal branch of the fifth nerve. The canals are con-
tinued outwards obliquely from a point coinciding nearly with the commencement of
the cranial cavity and brain, and thus mark off" a posterior region ((/) of the phosphorescent
organs.

The phosphorescent organs form membranous structures about 0"04 mm. in thick-
ness, which are stretched over the entire floors of the two cavities described. They
probably, in the recent state of the animal, lie close to the floors of the cavities. They
rise vertically up the sides of the median septum as they extend inwards towards the
middle line on either hand, and thus present their free edges to view on either side of the
septum when viewed through the skull-roof from above. Their edges are similarly
turned up to the surface all along their margins, and lie all round immediately in
contact with the transparent skull-roof (PI. LXVIII. fig. 2, W. V.).

The view of the phosphorescent organs is completely obstructed by the bony canals
(fig. 1, T) and thus on either side of the median septum there appear to be isolated strips of
the organ. The posterior areas of the phosphorescent organs (fig. 1, d) appear somewhat
isolated as they lie immediately above the roof of the cranial region of the skull, and
thus very near to the surface. In contrast with them the immediately adjoining regions

REPORT ON THE DEEP-SEA FISHES. 271

of the organs which occupy the floors of the orbital (?) cavities (fig. 1, a) lie so deep as to
be almost or quite invisible from the surface. It is only in the regions where the phos-
phorescent organs lie very near the skull-roof, that their component hexagonal bodies
can be seen with a microscope in the uninjured condition of the fish.

The phosphorescent organ is of identical structure throughout its extent, and no
difi"erence in its composition could be detected in its various regions. When it is viewed
from above it is seen to be marked over its entire upper surface with a series of
hexagonal areas of about 0'04 mm. in diameter. When its surface is viewed by reflected
light, the appearance is of a number of glistening, white, isolated, short columns,
hexagonal in outline, standing up in relief from its basal membrane (PI. LXVIII. fig. 3).
The organ forms a continuous membranous expanse about 0'04 mm. in thickness, excluding
the connective tissue and vascular layer. It is composed of the hexagonal columnar masses
arranged with considerable regularity in rows, and resting inferiorly on a pigmented con-
nective tissue layer. Each hexagonal column is composed of a number (about thirty or forty)
of transparent rods disposed side by side at right angles to the outer surface of the organ,
and with their bases applied against the concave surface of a large hexagonal pigment-cell,
one of which forms the base of each hexagonal column. The basal pigment-ceUs (figs.
10, 14) are hexagonal in outline and are cup-like, concavo-convex in form and of the same
breadth as the hexagonal columns. The under surface of the phosphorescent organ is thus
covered with a series of hexagonal areas each presenting a rounded convex prominence
(fif. 5, c). The outer extremity of each rod is surmounted by a hexagonal nucleated
cell (PL LXVIII. figs. 5, 6, 7).

In stained sections (fig. 5) each phosphorescent organ is seen to be composed of
three strata ; the superficial layer of cells (e) deeply stained, the layer of rods very little
stained and the layer of pigmented-cells (c) conspicuous by its dark bro^Ti colour.

The superficial layer is composed of cells all alike, of hexagonal outline, each with a
large nucleus filled with fine granules. The protoplasm of the cells also contains
granules. These cells are present in exactly the same number as the rods, and each when
m situ forms the summit of the rod beneath it. The cells of this layer are closely
connected together and the layer composed of them is frequently found in microscopic
sections separated as a continuous sheet from large areas of the organ, leaving the ends
of the rods exposed.

The rods (figs. 6, 7) are more or less regularly hexagonal in section apparently
perfectly clear, hyaline and transparent in structure. They appear to taper slightly
towards their lower extremities where they rest on the concave surfaces of the
hexagonal pigment-cells. In some few preparations I have seen a highly stained small
oval nucleus present in the lower extremities of certain rods, but have failed to detect
such in the large majority of instances (fig. 8).

The basal hexagonal pigment-cells have each a well-marked nucleus. Their substance

272 THE VOYAGE OF H.M.S. CHALLENGER.

is full of fine brown pigment granules (fig. 6, d). They form an apparently continuous
pigmented layer at the base of the phosphorescent organ, but the lines of separation of
the margins of the cells can be clearly detected with a high power of the microscope
(fig. 6).

The phosphorescent organs are traversed by small blood-vessels (figs. 4, 6), in abund-
ance. These vessels may be seen ramifying in the organs when viewed by a strong light
in the uninjured fish. They appear to be more or less correspondingly arranged on the
organs of opposite sides. The capillary vessels appear to traverse the organs superficially
to the pigment-cells and amongst the bases of the rods, since the tips of the rods may be
detected as present above them by careful focussing when an organ is viewed from the
surface.

When a portion of a phosphorescent organ is examined with a deep focus from the
surface, a network of ramifying pigmented strings and fibres is observed, which lies just
above the hexagonal pigment-cells and includes the hexagonal columns in its meshes
(figs. 6, 12, 13, 14). The pigmented strings follow mostly the lines of junction of the
margins of the hexagonal pigment-cells and thus surround the bases of the hexagonal
columns, but they also form long main stems extending for considerable distances in a
definite direction, and give ofi" numerous confiecting offsets which may directly cross the
hexagonal areas. They also send vertical ofi"sets up between the columns which give off
fine ramifications and form partial networks at the surface of the phosphorescent organs,
amongst or just below the superficial cells. The strings are very deeply coloured by the
presence of dark brown pigment-granules. They show enlargements at their points of
junction, and these enlargements contain in their interior small masses of pigment
darker than the general pigment.

Beneath the components of the phosphorescent organs already described is a layer of
connective tissue, which contains numerous large ramified pigment-cells such as occur com-
monly in the pigmented tissues of other fishes, and which is also traversed by nerves and
blood-vessels (figs. 15, 16). I am uncertain whether in the recent condition this connective
tissue layer is always in close relation with the under surface of the phosphorescent
organ. It is frequently found widely separated from it in my sections, but I think it
most probable that, in the recent condition of the animal, it lies closely applied to
the floor and against the walls of the phosphorescent organ cavity, with the imder
surface of the phosphorescent organ closely applied to and in contact with it. It
is shown in fig. 2 as seen in an actual section, where it is detached both from the
phosphorescent organ and the floor of its cavity, excepting towards the outer margin of the
latter. It is attached towards the middle line to the sides of the ethmoid septum where
the latter unites with the ridge of the roof of the skull. No doubt it supplies nerves and
blood-vessels to the phosphorescent organs. Blood-vessels are frequently seen in sections
attached to the under surface of the phosphorescent organ by parts of the connective-

REPORT ON THE DEEP-SEA FISHES. 273

tissue layer, as shown in fig. 6. In some instances these blood-vessels are seen to give
off branches to join the capillaries within the substance of the pliosph orescent organ.
I have also traced nerve-fibres from the connective-tissue layer to the region of the
pigmented hexagonal cells, but have not been able to observe any satisfactory connection
between them and the elements of the organ.

The phosphorescent organs receive a specially rich blood supply, in the form of a
pair of large vertically directed branches of the main blood-stems traversing the base of
the skull, apparently the carotids.

I have not found any distinguishable traces of rudimentary eyes or of optic nerves in
the Ipnops examined. The Gasserian ganglia are specially large and well developed,
composed of numerous large multipolar ganghon cells, and although no distinct nerve
connection has been traced, there appears to be little doubt that the nerves passing to the
phosphorescent organ from the connective tissue layer originate from the fifth nerve. No
trace has been found of any other source of nerve supply for the organ. It is just possible
that the network of pigmented strings may have some connection with the nerve-system.

The phosphorescent organs can hardly be sense-organs since they appear to be
supplied with no special nerves but only by ordinary nerves. They are certainly not
modified eyes.

The richness of theii- blood supply is in favour of their being phosphorescent organs,
as is also the extreme transparency of the portion of the roof of the skull covering them.

They can scarcely be electric, since there is an entire absence of the definite connective-
tissue walls of insulation between the hexagonal bodies so characteristic of electric organs.
No olfactory nerve was found in the sections of Ipnops, and apparently the nasal organs are
in a condition of abeyance of function. No olfactory membrane was detected in them.

The auditory nerve is well developed.

The interstices between the muscular fibres of the specimen examined are everywhere
crowded with parasitic psorosperms (spores of Myxosporidia) of pseudonavicellar shape,
showing that fish are not free from the attacks of Sporozoa at great depths.

Comparison of the Phosphorescent Organs of Ipnops with allied Organs of

other scopelids.

The phosphorescent organs of Ipnops show in certain points of structure a close
affinity with the so-called " eye-like bodies " of other Scopelids, as described by Ussow,
Leydig ^ and other authors, whilst in others they differ from them most remarkably.
Moreover, in some points of structure they resemble the organs of one genus of Scopelids,
in others those of other genera, thus combining the peculiarities of several.

Thus the rod layer in Ipnops is closely similar in general appearance to the unbroken

' Die augenahnlichc'U Oryaue iler Fische, Bonn, 1881.

(ZOOL. CHAIX. EXP. — PART LVII. — 1887.) "^l' "^^

274 THE VOYAGE OF H.M.S. CHALLENGER.

layer of narrow transparent rods present in the accessory eye of Stomias anguilliformis
as figured by Ussow^ (Tab. ii. fig. 10, h) ; but the component rods here, as in all alhed
organs of fishes as yet described, have no hexagonal terminal nucleated cells attached
to their extremities. Moreover, the hexagonal cells (?) forming the layer beneath
the rods are in Stomias filled with iridescent rod bodies (" Flitterchen " of Leydig),
forming what Ussow, who holds the organs to be eyes, calls a tapetum ; whilst
in the case of the organs of Ipno^ys no such iridescent layer is present, but
only in its place a layer of hexagonal pigmented nucleated cells exactly like that
occupying a similar position in the corresponding organ of Chaidiodus sloani (Ussow,
loc. cit., Tab. ii. fig. 8). In this organ of Chauliodus, however, the rod-like bodies bear
scarcely any resemblance to those of Ipnojos, being immensely long, with one extremity
club-shaped and the other drawn out into a fine filament. A still more important
difference is the absence of any trace of the lens-like bodies present in the organs both
of Chauliodus and Stomias. There seems to be no ti'ace at all of the iridescent
structures in Ipnoiis. Leydig appears to question the accuracy of Ussow's determination
of the polygonal pigmented objects as cells in every instance,^ but there can be no doubt
that the bodies forming the layer beneath the rod layer in the organs of Ipnops are
cells, since tliey have a well-defined nucleus, which may be well stained with carmine.
On the whole, though the organs of fynops show to some extent corresponding structure to
the " augenahnliche Organen " of Leydig it is evidently rather with the two other groups of
his classification (Leydig, loc. cz^.,pp. 64, 70, 73), the " Glasperlen-iihnlichen Organe " and
the " Leuchtorgane," that they are most closely allied. The former are described as slight
plate-like depressions of the outer skin surface with a dome-like transparent roof, with the
following structure in all species. An outer brown pigmented capsule, a layer with a
metallic iridescence, a connective tissue gelatinous body, nerves and blood-vessels. In
many species there is present besides a spindle-shaped string or plate of homogeneous
granular constitution.

The organ in Ipnops possesses the nerves though apparently not so richly develojjed,
the blood-vessels and the brown pigmented capsule, and a representative of the layer
with the metallic glance, in the hexagonal pigmented cells devoid of such glance. It has
no trace of a gelatinous body, but the spindle-shaped string or plate may be represented
in it by the rod layer. In the glass-bead-like organs of Scopelvs rissoi, the plate shows
a striate arrangement of its component granules (Leydig, loc. cit.. p. 45).

Leydig examined the two pairs of phosphorescent organs on the head of Scopehis
rajinesquii, but unfortunately for lack of material was unable to make out a complete
account of their histology ; he, however, convinced himself that their structure is

* M. Ussow, Ucber den Ban der sogeiiannten augeniihnlichen Fleckeii einiger Knochenfische, Bull. Soc. da
Naturalistes de Moscoii, 1879.

'■^ Leydig, Die augeniiluilichen Organe der Fische, Bonn, 1881, pp. 71, 72.

REPORT ON THE DEEP-SEA FISHES. -27.")

closely like that of the pearl sjjot on the tail of Scopelus humboldtii. These phos-
phorescent organs or " Leuchtorgane " differ from the glass-bead organs in having no
gelatinous refractive media. They have the pigment capsule, the blood-vessels, and
the layer of polygonal elements, with metallic glance, like the glass-bead organs, and
inside this layer a layer of substance which is to be regarded (Leydig, loc. cit.,
p. 73) as a specialisation and expansion of the spindle-shaped plate of the gla.ss-
bead organs.

This inner substance ought to be homologous with the rod layer in Ipnops, Ijut
unfortunately its structure as described is very indefinite, probably from the imperfec-
tion of the material used. In the phosphorescent organs of Scopelus rajinesquii it is
stated to be a grey layer of a peculiar transparent homogeneous fine granular substance.
In the pearl spot organ on the back of the tail of Scopelus humboldtii, it is said not to
be composed of cell elements, but made of very finely granular material traversed
by channels through which the blood-vessels pass. Nevertheless, on side view, an
appearance is seen as if it were composed of pear-shaped elements (Leydig, loc. cit.,
pp. 53, 54). From the figure given of the microscopical structure of this layer (Leydig,
loc, cit, Taf. X. fig. 61), and the description of its peculiarities, it seems possible that it
may eventually prove to be made up of fine rods something like those composing the
rod layer in Ipnops. The small blood-vessels traverse the layer just as in the case of
the rod layer of Ipnops. Leydig describes the cell elements lying next to the tapetum
in the eye-like organs of some fishes as approaching in form and power of refraction
the crystalline rods of Arthropoda ; these must surely be identical with the rod bodies of
Ipnops (Leydig, loc. cit., p. 80).

On the whole, it seems not unlikely that the remarkable head organs of Ipnops are
to be regarded as highly specialised and enormously enlarged representatives of the
phosphorescent organs on the heads of such allied Scopelidae as Scopelus rafinesquii
and Scopelus metopoclampus (Leydig, loc. cit, Taf. x. figs. 55, 56). It maj- l)c
conceived that in Ipnops the supra-nasal and subocular phosphorescent organ of these
species on either side have united and become one, with the result of the total obliteration
of the eye. In Scopelus metopoclamp)us there is a notch which nearly separates the
subocular organ into two parts. In the organs of Ipnops there is a similar notch due
to an incursion inwards of their pigmented borders on either side (see PI. LXVIL), but
it lies on the outer, not on the inner margin of each organ.

The phosphorescent organs in Ipnops lie entirely outside the cavity of the cranium,
although they sink over part of their anterior region into two cavities on either side of
the median septum of the skull. Posteriorly they lie quite close to the .skin surface on
the top of the cranial wall. The margins of the rod layer and pigment layers are every-
where superficial. The exact extent to which the transparent roof of the organ is
ossified was not made out, as no .specimen was available for maceration. The organs are

276

THE VOYAGE OF H.M.S. CHALLENGEE.

bounded interiorly by the connective tissue pigment-bearing layer, no doubt of dermic
origin, as in the organs of the Scopelidse.

The most important point in which the organs of Ipnops appear to differ from the
group of allied organs in fishes generally as yet described seems to be the nature of the
rod layer. The rods in Ipnops are hexagonal in section and show no tendency to
taper to fine filaments at either end. At the free end directed towards the exterior and
the light, they are capped by very definite and distinct hexagonal nucleated cells, which
easily become detached from them as a continuous membranous sheet. At their
opposite extremities the rods abut on the concave surfaces of the hexagonal pigment-
cells by broad hexagonal bases, as may be seen by viewing their ends through the
substance of these cells. No arrangement of rods such as this has been described in
any phosphorescent or allied organ from a fish. The absence of tapetal plates is a
matter of less importance. They seem to be represented by the hexagonal pigmented
cells. The brown pigmented network described as traversing the basal regions of the
rod layer in Ipnops, and sending up fine branches which ramify at its surface,
apparently corresponds with the " Fachwerk " traversing the grey body in the eye-like
bodies of other fishes (Leydig, loc, cit., p. 68). This network is the only structure which
I have found in Ip)nops which would in any way correspond with the structures figured by
Ussow as ganglion cells in what he terms the retina of the eye-like bodies of ChauUodus
sloani (Ussow, loc. cit., Ta£ ii. fig. 7).

APPENDIX B.

KEPOET on the Structure of the Phosphorescent Organs of Fishes. By R. von
Lendenfeld, Ph.D., F.L.S., Assistant and Demonstrator in the Biological
Laboratory of University College, London.

PREFACE.

Most of the deep-sea fishes and also some pelagic surface fishes of nocturnal habits
collected during the voyage of H.M.S. Challenger, possess certain organs which appear
to have the function of producing light — in the case of deep-sea forms — to illuminate the
eternally dark abysses of the ocean.

Dr. Giinther, whilst engaged in the examination of the fishes collected by H.M.S.
Challenger, intrusted me with the histological investigation of these organs in such speci-
mens as could be spared for this object, and the results of these researches wiU be found
in the following pages. It is my pleasant duty here to express my thanks to Dr. Giinther
for his ereat kindness in assisting me to brine these studies to a successful issue.

Although the specimens examined by me are for the most part remarkably well
preserved, still the most minute histological details would have remained doubtful on some
points, if I had not had other material, specially preserved for histological purposes,
to compare with the Challenger specimens. Where it was necessary I have embodied
in this Report the descriptions of the structure of the phosphorescent organs in
such specimens. I must express my thanks to Professor Ray Lankoster who placed
some excellent material for this work at my disposal, and in whose laboratory tlie
necessary series of sections were prepared.

The phosphorescent organs were studied principally by means of series of sections,
cut in the usual manner after embedding in paraflin ; they were stained with Klehicn-
berg's hsematoxylin, borax-carmine, alum-carmine, or picrocarmine. The last named
produced the best results.

278

THE VOYAGE OF H.M.S. CHALLENGER.

CONTENTS.

I. HISTORICAL INTRODUCTION,

IL THE DIVERSITY OF THE PHOSPHORESCENT ORGANS, . . . .

Ill SPECIAL DESCRIPTION OF THE DIFFERENT KINDS OF PHOSPHORESCENT
ORGANS,

A. Regular Ocellar Organs, .....

1. Simple oeellar organs without pigment coat, sunk in the body,

a. Distrihvtion,
h. Structure,
<:. Innervation,

d. Function,

e. Develojnnent,

2. Simple oceUar organs with pigment coat, sunk in the body,

a. Distribution,

h. Structure, ,

<:. Innervation,

d. Function,

e. Development,

3. Composite oceUar organs without reflector,

a. Distribution,

h. Structure,

c. Innervation,

d. Function,

e. Development,

4. Composite oceUar organs with special reflector,

a. Distribution,

b. Structure,

a. General,

(1) The organs of Gorwstoma,

(2) TJie dorsal organs or " stern-chasers" of Scopelus,

(3) The groups of lateral organs in Argyropeleciis and Sternoptyx,

(4) The ventral roivs of Argi/ropeleeiis and Sternoptyx,
ji. Histology, ......

c. Innervation,

d. Function, ......

e. Development, ......

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281

283

285

285

285
285
286
287
287
288

289
289
289
291
291
292

292
292
293
298
299
300

300
300
301
301
302
302
303
303
303
306
306
307

REPORT ON THE DEEP-SEA FISHES.

279

6. Regular ocellar projecting organs,

a. Digtribidion,

b. Structure,
e. Imiervatinn,

d. Function,

e. Develoinnent,

f. Doubtful structures in the skin,

6. Regular ocellar covered organs,

a. Distribution,
h. Structure^

a. General,

/3. Histology, .

(1) The scales, .

(2) The pigmented membranes.

(3) The light-reflecting membrane^

(4) TJie phosphorescent organ,

(5) The slime-canal and its branches,

(6) The tissue overlying the slime-canal,

(7) The meandriform gland-tubes,

c. Innervation,

d. Function,

e. Development,

B. Ieregulae Glandular Organs,

7. Glandular organs of irregular position, .

a. Distribution,
I). Structure,
c. Function,

8. Glandular organ on the lower jaw,

a. Distribution,

b. Structure,

c. Function,

9. Dififerentiated barbels and fin-rays,

a. Distribution,
h. Structure,
c. Function,

10. Glandular organs under tlie gill-covers,

a. Distribution,

b. Structure,
^c. Function,

11. Suborbital glandular organs without reflector,

a. Distribution,

b. Structure,

(1) In Astronesthes niger,

(2) In Opostomias micripnus,

c. Innervation,

d. Function,

e. Development,

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307
307
307
308
308
308
308

309
309
309
309
310
310
310
310
310
311
311
312
312
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313

313
313
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314
314

314
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315

315
315
315

315

315
315
316
316

316
316
316
316
317
319
319
319

280

THE VOYAGE OF H.M.S. CHALLENGER.

in Pachystomias microdon,

12. Suborbital organs with reflector,
a. Distribution,
h. Structure,

(1) General, .

(2) Special description of the suborbital organa

a. General appearance, .
13. The smaller anterior organ,
y. Tlie larger posterior oi-gan,

c. Innervation,

(1) In general, .

(2) The brain of Echiostoma barhatum.

d. Functiwi,

e. Development,

CONCLUSION,

a. Comparison of the different phosphorescent organs of fishes.

b. The typical phosphorescent cells, .

c. The phosphorescent organs of fishes compared with those of some other animals, .
Scheme of the development of phosphorescent organs,

EXPLANATION OF PLATES, ....
Key to the figures on the Plates, . . .

PAGE
319

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322
.322
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323

323
323

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327

328
328

REPORT ON THE DEEP-SEA FISHES. 281

I. HISTORICAL INTRODUCTION.

Before entering into the results of this research it may be advantageous to Ijring
to the recoUectiou of the reader the investigations on this subject published by
other authors. In doing so I shall strictly confine myself to the papers on the Histology
of these organs.

The first who paid special attention to the histology of these organs was R. Leuckart,^
who called them " accessorische Augen."

Afterwards, Ussow" published a short account of these organs. He examined
Chaxdiodns, Stomias, Scopehis, and Argyropelecus, and came to the conclusion that in
these genera the organs in question were, as Leuckart had assumed, accessory and
segmentally grouped eyes. Theii- structure is compared with that of the so-caUed com-
posite organs with a simple cornea.

Ussow compares them directly with the ocellar segmentally distributed accessory
eyes of Euphausia.^

Afterwards, Ussow studied these structures in some other species, and published a
very detailed account* of his researches, which were made on the organs of the following
species : —

Astronesthes martensii.
Stomias anguilliformis.
Stomias barhatus.
Chauliodus sloani.

Chatdiodtis setinotus.

Scopdus rtssoi.

Maurolicus am,ethystina-punctatus.

Gonostoma denudatum.

A rgyropelecus liemigymnus.

It appears that he only examined those organs which arc designated ocellar organs
in this Report. He did not extend his investigations to those found chiefly on the
head, which I call glandular organs. He comes to the conclusion that those which are
more simple in their structure are glandular in function, although they have no external
opening. I can endorse Ussow's descriptions and figures of these organs.

The more complicated organs, which are incised near the middle, and which are
designated below as " composite ocellar," are considered by Ussow as eyes.

His descriptions and figures of these are not in accordance with the results obtained
by Leydig and myself

1 R. Leuukart, Ueber mutlimassUche Xelienaugen bei eineni Fische, lieruht U. d. Versamml. deuUch. Naturf., 18(54.

2 M. Ussow, Arbeiten d. Gesellsch. d. Naturf. St. Petersb., Bd. v. p. 70, 1874.

3 According to G. O. Sars (Report on the Scliizopoda collected by H.JI.S. Clialleuger, Zool. Cliall. E\\>., part
xxxvii.) these are not eyes but phosphorescent organs.

4 M. Ussow, Ueber den Ban der sogenannten angenahnlicheu Flecken einiger Knochenfische, Bull. Sac. imp. den
Nat. Moscou, t. liv. No. 1, p. 79, 1879.

(zool. ch.aj.l. EXP. — PART Mil. — 1887.) Lll 36

282 THE VOYAGE OF H.M.S. CHALLENGER.

The most important work on this subject has been published by Leydig/ who
examined the following species : —

Gonostoma denudatum.
Ichthyococcus ovatus.
Ichthyoccocus pcdmerise.
Argyropelecus hemigymnus.
Scopelus rissoi.

Scopelus humboldtii.
Scop>elus henoiti.
Scopelus bonapartii.
Scop)elus rafinesquii.
Scopelus meto2Mclampus.

Leydig divides the organs examined by him and described by previous authors into
three groups : — " Augenahnliche Organe," " Glasperlenahnliche Organe," and " Leucht-
organe."

The meaning of these terms as compared with those used by Ussow and myself will
be explained below.

The description given of the microscopic structure of these organs I am able to
endorse ; but minute details are not described, and most of the material at Lej^dig's
disposal was not in very good condition.

Leydig considers these organs as "electric or pseudoelectrie." This positive state-
ment appears rather vague, but his negative assertions, however, arc very decisive. He
combats the view held by Ussow (loc. cit.) particularly, that these organs are accessory
eyes, and he decides with equal emphasis that they are not glandular.

He acknowledges that they may emit light, but he thinks that this is not their
primary or principal function. He considers them as pseudoelectrie apparatus which
may in some cases emit light.

From this it appears that the physiological results are not at all in proportion to the
excellence and extent of the facts and observations on the subject hitherto ascertained.

Emery" has published a description of the minute structure of the phosphorescent
organs of Scopelus. He gives a correct figure, but has failed to observe the cells
described below, which appear so very peculiar, and which, being found in all these
organs, may be considered as their principal constituents.

He considers the reflector at the back of the organ to be an inverted scale, and says
that the organ is covered by another scale, which has been converted into a lens. He
considers these organs to be phosphorescent.

I shall now enter on the resvdts of my own studies on this subject, postponing the
consideration of their physiological and general results to the end of this Report.

Although these organs appear to be of uniform histological structure in different
groups of fishes, they nevertheless present such differences in shape, distribution, and
origin in the different groups that it appears advantageous to dwell on the different forms
separately.

' F. Leydig, Die augeniihiilichen Organe der Fische, 10 pis., Bonn (E. Strauss), ISSI.
'' E. Eniery, Mittheil. d. zool. titatiov zu Neapel, Bd. v.

REPORT ON THE DEEP-SEA FISHES. 283

II. THE DIVERSITY OF THE PHOSPHORESCENT ORGANS.
The following species were examined by me : —

Opostomias micripnus.
Echiostoma barbatum.
Pachystomias microdon.
Malacosteus indicus.
Astronesthes niger.

Argyropelcc us hemigyinnns.
Sternoptyx diaphana.
Scopelus benoiti.
Xenodermich thys nodxdosus.
Halosa urns macrochir.

Halosaurus rostratus.

In these fishes a great many different kinds of phosphorescent organs are met with,
and all the various forms described by Ussow, Leydig and Emery, are represented in (jne
or more of them.

I distinguish twelve different kinds of phosphorescent organs in these fishes, whicli
may be divided into two main groups.

Scattered more or less regularly in segmental distribution over the ventral side or
the whole of the body, small, regulax*, bulbous organs sunk into the body are met with,
which have been designated by Ussow as " augenahnliche Organe" and )jy Leydig as
"augeniihnliche " and "glasperleniihnliche " organs.

I term these "regular ocellar phosphorescent organs." They may be "simjile" or
" compound." The former correspond to those organs u liich are described as glandular
by Ussow and partly also to the " augentihnlichen Organe " of Leydig. The latter, the
compound regular ocellar phosphorescent organs, are particularly the ones considered as
"augenahnliche" and " glasperlenahnliche " organs by the authors mentioned.

The simple ocellar organ is more or less s^iherical, closed on all sides and generally
partly invested by a pigment coat ; its internal structure appears radial.

The composite ocellar organ is divided into two parts, an interior closed spherical
portion divided by an annular incision from the cup-shaped external portion. Some-
times several of these composite organs stand close together, and tlien their spherical
basal portions may coalesce so as to form a canal or tube, to one side of which the cup-
shaped outer portions of the joined organs are attached.

The simple ocellar organs may or may not have a pigment coat.

The composite organs always have a pigment coat, Ijut they ma}- (U' may not be
provided with a layer of threads or spicules, which shine like silver, refract the light
strongly, and act as reflectors. The composite ocellar organs with reflectors are identical
with Leydig's " glasperleniihnliche " organs. They are always very ol)lique to the surface,
whilst those which are destitute of a light-reflecting layer ajipear generally more or
less perpendicular to the outer surface.

284 THE VOYAGE OF H.M.S. CHALLENGER.

Exceptionally also simple ocellar organs are found attached to the outer surface of
the body and apj^ear as spherical projections.

The lateral line may be converted into a series of ocellar phosphorescent organs,
every one of the scales which cover the lateral slime-canal bearing on its outer surface a
phosphorescent organ connected with the tissue below by a central perforation of the
scale.

We have, therefore, the following six kinds of regular ocellar phosphorescent
organs : —

1. Regular ocellar simple phosphorescent organs sunk in the body, without

pigment coat and without reflector.

2. Regular ocellar simple phosphorescent organs sunk in the body, with pigment

coat and without reflector.

3. Regular ocellar composite phosphorescent organs sunk in the Ijody, without

reflector.

4. Regular ocellar composite phosphorescent organs sunk in the body, with

reflector.

5. Regular ocellar simple phosphorescent organs attached outside to the body.

6. Regular ocellar orsjans attached to the differentiated lateral line.

The irregular glandular phosphorescent organs are always found on the head, and
besides, sometimes also on the sides of the body (Astronesthes), on the tail (some species
of Scopelus, Leydig), and on specially differentiated barbels {Ojwstwnias micripnus,
Malacosteus indicus).

These have not been taken notice of hy Ussow ; they are designated by Leydig as
" Leuchtorgane."

Six kinds of glandular organs are met with : —

1. Glandular organs scattered irregularly.

2. Glandular organs on the lower jaw.

3. Glandular organs on the barbels.

4. Glandular organs under the gill-cover.

5. Suborbital, highly differentiated glandular phosphorescent organs without

reflectors, and

6. With reflectors.

These may accordingly be with or without reflectors. A pigment coat is, how-
ever, invariably present in all the different kinds of irregular glandular phosphorescent

REPORT ON THE DEEP-SEA FISHES. 285

Tlie following table shows how these various kinds of phosphorescent organs are
distributed in the species examined by me : —

•is

|.|

ii

II

.1 .

II

1'

II

s

It

ii

.2 a

I.I
II

§■2

!i

"11

il

ll

It

1

ii

il

f On scales of lateral line, without j

simple, . . . pigment, \

( without ^

pigment, /
■ simple, i

1 with pig- \
{. ment, /

X

X

X

X

X

Regular
ocellar.

Sunk,

.composite, ■

■ without 1
reflector, V
vertical, )

with )

X

X

X

X

Phosphorescent
Organs.

.Projecting, simple.

reflector, >
. oblique,

with pig- (
ment, (

X

X

X

X

( irregularly,
r Scattered, .-!

X

\ on lower jaw,

X

X

Irregular

On biirbcls,

X

X

w glandular.

Under gill-cover, ....

( without reflector,
^ Suborbital, -!

|_ with reflector,

X

X

X

X

X

X

X

III. SPECIAL DESCRIPTION OF THE DIFFERENT KINDS OF PHOS-
PHORESCENT ORGANS.

A. Regular Ocellar Organs.

1. Simple ocellar organs without pigment coat, simk in the body.

a. Distribution.

These organs have hitherto only been found in one species, Opostomias micripnus ;
and have not been observed by previous authors. In Op)ostomias micripnus they appear
as very small white spots scattered very abundantly on the sides and back of the
otherwise dark-coloured fish, and when magnified present the appearance of circular
patches from O'l to 0-3 mm. in diameter. They are not uniformly scattered over the
back of the fish, but appear in groups of from fifty to one hundred, and these groui)s

286 THE VOYAGE OF H.M.S. CHALLENGER.

take the shape of transverse bands, which are about 3 mm. broad, and divided from
each other by darker zones in which the white organs are scarce. Within the bands the
phosphorescent organs are on an average 07 mm. apart (from centre to centre).

Towards the ventral side these organs diminish in number and stand further and
further apart, until they disappear altogether below the line formed by the upper row of
composite phosphorescent organs on the side.

h. Structtire.

Surface views and section-series reveal the structure of these organs (PI. LXXII.
figs. 34, 35, 37). They are mostly lens-shaped, flat and extended, and sunk into the
skin of the fish for about half their height (figs. 34, 35). In other cases (fig. 37) they
appear nearly hemispherical, are not sunk into the skin at all, their hemispherical
surface projecting beyond the surrounding surface. The lower lens-shaped forms
likewise project beyond the surface, but not so much (fig. 34). They are from 0"! to
0"2 mm. high, and generally project about 0"07 mm. The flat lens-shaped form is pre-
dominant ; the high forms being rare and intermediate shapes by no means common.

The circumference is usually spherical, sometimes slightly irregular, never elliptical.

These organs do not seem to possess any special membrane, the common cuticle
passing over them, and the capillaries of the skin appear aggregated at the base of the
organ, whence bloodvessels extend up into the organ itself. These are on an average
0'02 mm. apart, and converge towards the centre of the organ at right angles to the
convex base. Between them radial tubes, rounded and closed at the distal ends, ar(-
situated, and these are filled with small granular spherical cells similar to those described
by UssowMn the gland tubes of the simple ocellar organs of Gonostoma denudatnm.
There is no difference between these cells and the homologous ones in the simple ocelhi.i-
organs with pigment coat.

The tubes in which these granular elements are contained are polygonal pyramids, with
their points cut ofi", and consequently their narrow converging ends, which are situated
near the centre, are open. The broader rounded distal ends are attached to the tissue
which is situated below the organ.

The walls of the tubes are thin membranes of connective tissue into which capillaries
and nerves extend. The nerves are medullated, the sheath disappearing apparently at
the points where the branches of these nerves enter the mass of granular cells.

In the material at my disposal the extreme nerve ends cannot be traced. Near tlie
centre of the organ, above the terminations of these pyramidal tubes, there is an empty
space extending right across the organ ; it has a shape somewhat similar to that of the

1 M. Ussow, Ucber deii Bau der sogenamiteii augenivhnlichen Flecken einiger Knochenfische, Ball. Hoc. imp. des
Nat. Moscou, t. liv. p. 98, pi, iii. fig. 11.

REPORT ON THE DEEP-SEA FISHES. 287

orgau itself, and is only lower and flatter in proportion. This space is not altogether
"empty" as the expression "empty space" might imply, for it appears filled by a
finely granular mass, evidently the secretion of the tubes containing the granular cells ;
it is, however, destitute of cells. Above this space, very narrow, slender and long
cells are situated which are perpendicular to the outer convex surface of the organ, and
extend between it and the central cavity, above referred to. These cells are spindle-
shaped, tapering to fine points at each end, and have elongated, oval nuclei, and
in consequence of their shape and position give to this part of the organ a
radially striped appearance. Just below the outer surface there is a granular zone
about 0"01 mm. mde, with spherical nuclei, but in this zone the radial structure is
rather obscured by the granules. The whole structure is exceedinglj^ transparent
and possesses — in spirit — that peculiar white colour which is so characteristic of all
these organs.

c. Innervation.

The medullary nerves found in the walls of the pyi-amidal tubes originate from fibres
which extend along the lower surface of the organ ; the latter form a kind of plexus in
that locality, which is connected with nerves belonging to the system of the spinal
nerves. The plexus and the branches which connect it with the spinal system are
modified dermal nerves.

d. Function.

From these facts we may conclude that these organs are composed of a gland,
consisting of closely packed and therefore flattened and polygonal tubes, on the lower
side, and a special phosphorescent apparatus above, which produces light at the volition of
the fish by using up or burning the secretion supplied by the gland and stored in the
space below. This phosphorescent apparatus is innervated from above, where a layer of
ganglion cells— the granular layer with the spherical nuclei — is found.

The state of preservation of these organs is not suflaciently good to allow of a more
detailed description, but the whole structure is so similar to that of some other organs to
be described, which I was able to study by means of excellent material, that I consider
myself justified in referring for further details to the descriptions of the phosphorescent
apparatus in the suborbital organs of Oiwstomias micnpyms, and the composite ocellar
organs in Scopelus henoiti.

At the first glance these organs, scattered in dense crowds over the fish, remind one
of the chromatophores of Cephalopods, and they are in all probability defensive arrange-
ments to frighten away fish of prey, which may attack them from above. Proba])ly the
fish, by simultaneously exciting certain groups of these organs, is able to emit light from
tliese areas. As the organs in difterent regions of the surface are successively incited to

288

THE VOYAGE OF H.M.S. CHALLENGER.

phosphorescence, clouds of light pass over the body. This may be compared to the
changing of the colour in Sepia, where the different hues travel over the body like
shadows of clouds.

e. Development.

Remarkable structures, like those represented in PI. LXXII. fig. 35, are occasionally
met with, which seem to indicate that these organs multiply by division. As the fish
grows in size, and the area to be occupied by these organs extends, it appears that they
multiply, and that they are not formed spontaneously in the skin of the adult fish at all.
No indications of a spontaneous formation of these organs have been observed.

From which organs in the skin these phosphorescent apparatus were originally
developed phylogenetically it is difficult to say. It appears most probable that they were
developed from small slime-glands of the skin, such as are found in all fish. The slime
of some Batrachians is luminous, and so the slime produced liy the small glands in
the skin of some fishes may have hy chance become slightly phosphorescent. This may
at a certain time, particularly when the fish in question took up its abode in great
depths, have become advantageous to them, and with tlie demand for a luminous slime
the glands would naturally have been modified in the course of time, so as to produce
slime more and more luminous, and afterwards, the duct leading from the gland out-
wards may have been closed and the luminous slime retained. The slender cells forming
the upper stratum of these organs are newly formed coenogenetic structures, and indicate
that these organs are already very highly differentiated.

These regular, ocellar, simple phosphorescent organs without a pigment coat are of
particular interest, as from them all the other forms may be supposed to have developed.
There is no doubt that these organs are by far the simplest of their kind hitherto
observed, and they appear to have retained the original character, which has been
much changed and further modified in the cases of the other kinds of regular ocellar
phosphorescent organs.

Their phylogenetic position is elucidated in the following table : —

Composite, with reflector.

Regular ocellar phosphorescent organs. -

Composite, without reflector.

Simple, with pigment coat.

Simple, without pigment.

Small slime-glands of the skin.

REPORT ON THE DEEP-SEA FISHES. 289

2. Simple, regiilar, ocellar phosphorescent organs with pigment coat, siink in the body.

a. Distribution.

These organs have been found by me in Opostomias micripnus and Pachystomias
microdon, scattered all over tKe body at intervals of from 1 to 3 mm. In Echiostoma
barbatum they occur in double transverse rows on the dorSal and ventral sides of the
body, while in Malacosteus indicus and in Astronesthes niger they are found on the
ventral side only. In these species their extent is laterally limited by the lower row of
composite phosphorescent organs.

Organs which belong to this group have been found by Ussow in Gonostoma
denudatum,^ Maurolicus amethystinopunctatus,^ and Scop)elus rissoi,^ and their position
corresponds, according to Ussow, with that of the composite phosphorescent organs in
other fishes. He seems to think that they replace the composite organs, without being
aware that usually (except in Sternoptyx and Argyropelecus) they are present in great
numbers together with the composite organs. Leydig has found such organs apparently
in Gonostoma denudatum, according to the figure.^ He describes them, however, as
having a reflector.

Ussow considers that these organs have a glandular nature and terms them
" dnisenartige Organe." He considers them to be homologous to those which he
believes to be accessory eyes. It seems rather difficult to understand how two similar
and homologous organs should be so difi"erent as Ussow would make out in this case.
Some of the " augenahnlichen Organe " of Leydig, those namely which are not composite,
likewise belong to this group.

These authors, however, have paid much less attention to these structures than to
the much more complicated and difierentiated composite organs, particularly those with
a reflector, and, consequently, the great and fundamental difi'erence between the simple
and composite organs has escaped their notice. Both seem to have considered the
presence or absence of the reflector to be of paramount importance, and did not consider
that some organs without reflectors were constructed on quite the same principle as others
which possess a reflector.

b. Structure.

The structure of these organs has been described by Ussow,' and his figure (pi.
iii. fig. 11) gives a fair representation of the internal structure. Such differences

• M. Ussow, Ueber den Bau tier sogeuannten augeniihalichen Fleckeu einiger Knochenfische, Mim. Soc. imp. des
Nat. Moscou, t. liv. pp. 97, 98, pi. iii. fig. 11.

2 M. Ussow, he. cit., p. 101, pi. iii. tig. 12.

3 M. Ussow, loc. cit, pp. 99-100, pi. iii. fig. 13.

* F. Leydig, Die augenahnlichen Organe der Fische, p. 15, pi. i. fig. 6. ^ M. Ussow, loc. cit

(ZOOU CHALL. EXP. PART LVII. — 1887.) I^" "^^

290 THE VOYAGE OF H.M.S. CHALLENGER.

as Ussow found in different species certainly do not exist between these organs of the
various species examined by myself. The differences in Ussow's figures (pi. iii. figs.
11, 12, 13), might be accounted for by his having studied sections made in diflferent
directions.

The only form of this organ seen by me is the following : —

A sac is attached to the cuticle, which is about as deep as wide, cylindrical, rounded
below, and opening outwards by a circular aperture, which is covered by a continuation
of the cuticle as in the case of the simple organs without a pigment coat described above
(PL LXIX. figs. 2, h, 5, 10 ; PI. LXXII. fig. 38).

These sac-shaped organs measure 0"3 to 0*5 mm. in diameter. The sac (PL- LXIX.
fig. 5 ; PI. LXXII. fig. 38) is formed of a dense layer of pigment, similar to the pigment
found in the skin in other locaHties, and to the naked eye these organs therefore appear
as darlc spots scattered over the skin.

These pigment-sacs, which appear very striking and prominent in sections, are
generally slightly expanded at the base and contracted near the mouth (PL LXIX. fig. 5),
with their axis sometimes perpendicular to the surface of the skin (PL LXIX. fig. 5) as
m Astro7iestlies, and sometimes oblique (PL LXXII. fig. 38), as in Echiostoma barbatum.
The thickness of the pigment-layer forming this sac is 0"02 mm. The sac is surrounded
by a loose plexus of bloodvessels ' and nerves, from both of which branches arise and
penetrate the pigment-layer. The cornea-like continuation of the cuticle which closes
the sac is convex, watch-glass-shaped (see figures).

The internal structure appears to be very similar to that of the simple organs without
a pigment coat. The lower, proximal part of the sac is occupied by radially placed
pyramidal gland-tubes, closely packed, and, therefore, flattened against each other.
Their wide distal ends are rounded, and nerves and bloodvessels radiate upwards
between the tubes. The membranes forming the tubes are very fine, and the tubes have
an average width of 0'04 mm. at the base and 0'02 mm. at the distal, open end.

These tubes are Jilled with spherical or slightly irregular granular cells, which are
very similar to those attached to the wall of the gland-tube. The cells have an average
diameter of 0 "0 1 mm. ; Ussow ^ has given a good representation of them. In the centre
of the organ, within the terminations of the gland-tubes, there is a space 0"06 mm
wide, which is filled with a granular secretion.

The portion of the organ underlying the cuticle is also granular, but it is easy to
perceive that this portion of the gland is occupied by cells. In Ussow's^ figure
(pi. iii. fig. 13), these cells are represented (Scopelus rissoi), but I have never observed
them nearly so distinct. The spherical nuclei in the outermost layer, with a diameter of
0"002 mm. (which are not so large as represented in Ussow's figure, loc. cit.), become

' Compare F. Leydig, Die augenalinliclien Organe der Fische, pi. i. fig. 6.
^ M. Ussow, loc. cit. 3 -^i Ussow, loc. cit.

REPORT ON THE DEEP-SEA FISHES. 291

clearly visible after staining. The limits of the cells, however, remain indistinct.
Below this outermost layer of indistinct cells, which has a thickness of 0-026 mm.,
and Avhich appears to consist of a single layer of these cells, a striated structure is
met with. This fills the interval between the central cavity and the outer layer of
cells. The striae are vertical to the outer surface, and indicate that this part of the organ
is composed of the same narrow slender cells described above as forming the homologous
part of the simple glands without pigment coat. There is a single layer of them ; they
are 0'03 to 0'05 mm. long, and in the thickened centre, where the elongate nucleus is
situated, 0'0015 mm. thick.

It appears from this that the only structural difierence between these organs and
the regular, ocellar, simple phosphorescent organs without pigment coat is the absence
of the pigment coat in the one, and the presence of it in the other kind.

c. Innervation.

The nervous plexus which surrounds these organs is connected with branches of the
spinal nerves in the same way as has been described above in the case of the organs
without pigment coat.

d. Function.

It appears that the radial tubes in the proximal portion of the organ, which are fiUed
with granular cells, are true gland-tubes. These glands are com^jarable to the milk
glands in mammals, inasmuch as the secretion which is formed does not appear as a
segregation of the cells, but the whole of the cell is bodily converted into the substance
of the secretion. The cell is pushed from the wall of the gland-tube which is always
occupied by the youngest generation of cells ; and when disconnected from the capillaries
in the membrane of the gland-tube the cell undergoes a change. It loses its
nucleus ^ and finally also its individuality, its substance joining that of other similarly
degenerated cells. In this way the secretion which occupies the centre of the organ
appears to be formed.

At the expense of this secretion or fuel, the slender cells above it may produce light.
The outermost layer of indistinct cells with the highly colourable nuclei I consider to be a
nervous layer composed chiefly of irregular ganglion cells ; the slender cells appear to be
innervated from them.

The fish can probably produce light in these organs at wiU. They do not emit light
under ordinary circumstances when not excited to phosphorescence by the fish itself.

' -Ussow {he. (it.) figures nuclei in the detached cells occupying the interior of the gland-tubes. I have not seen
nuclei in the detached cells in my sections.

292 THE VOYAGE OF H.M.S. CHALLENGER.

Like the organs without pigment coat, these are probably incited to action in groups
and not singly, although there may be more individuality in their performance than in
that of the less highly differentiated organs without pigment coat.

The function of the pigment coat is probably to shade the light at the sides, and to
concentrate it in one direction, which, of course, would be of advantage to the fish. Pos-
sibly the pigment is only to be considered as a residue of the chemical reactions which
go on in the organ.

e. Development.

I do not doubt that these organs have been developed from the simple phosphorescent
organs without pigment coat, and that they in this way represent the second stage in the
development of the ocellar phosphorescent organs of fishes. Not only does their structure
indicate a much greater differentiation, but also their distribution over the surface of
the fish is more sharply defined and not so irregular as in the case of the former organs.

3. Composite, ocellar, regular phosphorescent organs, without reflector.

a. Distribution.

Organs of this kind have been found by me in Opostomias micripnus, Echiostoma
barhatum, Astronesthes niger, and Pachystomias microdon.

These organs invariably appear in two rows on each side of the body, one lateral and
one ventral. The rows extend forwards on the lower side of the head, a row on the pro-
jecting crest of a fold below the operculum being especially conspicuous.

Ussow ^ has described the distribution of these organs over the body very carefully.
The organs in one row are from 2*5 to 5 mm. apart according to the size of the species.
Large specimens possess a much greater number of them than small ones.

The organs which Ussow calls " augenahnliche Organe " in Astronesthes martensii,'-^
Stomias barbatus,^ and Chauliodus sloani* belong to this group.

Some of Leydig's " augenahnliche Organe," which he found in Ichthyococcus ovatus ^
and in Ichthyococcus palmerise,^ likewise belong to this group.

In all the fishes in which these organs have been found, they are distributed over the
surface of the body in the same way, always occupying four lines.

In this respect the composite organs differ much from the two preceding kinds, which are
scattered much more irregularly over the surface and which never occur in distinct rows.

1 M. Ussow, loc. at., pp. 108, 109. 2 ]^];_ Ussow, loc. cit., p. 89, pi. ii. fig. 9.

3 M. Ussow, loc. cit, p. 91, pi. ii. fig. 10. * M. Ussow, loc. cit, p. 93, pi. ii. fig?. 6, 7.

* F. Leydig, Die augenalmUcliea Orgaue der Fische, p. 22, pi. vi. fig. 33. ° F. Leydig, loc. cit, p. 25.

REPORT ON THE DEEP-SEA FISHES. 293

h. Striicture.

The structure of these organs has been carefully studied by Ussow/ but I cannot here
give a review of all his statements. The main results, however, of his examination of
Cliauliodus, Astronesthes and Stomias, are the following : —

The organ consists of two parts, divided from each other by a constriction of the wall.
The outer portion is filled by a structureless liquid, the function of which is to protect
the tender structures below from the pressure of water. A complicated lens which is
composed of cells is situated in the constriction. It is convex in front and drawn out
into a cylindrical process behind.

The lower or internal chamber, which is designated as an eye, is occupied by radial
" Krystall Kegel." The spherical base is occupied by ganglion cells and the whole is
enclosed by a pigment coat.

Leydig ^ describes these organs in Ichthyococcus very differently indeed. According
to this author both the chambers of the composite organ are occupied by radial gland-
tubes filled with the well-known spherical granular cells. In the centre, near the
constriction, there is a space filled with a granular mass which is in connection with a
stout nerve entering the organ from without.

My own observations made on those of the four species mentioned above, are
in accordance with Leydig's {loc. cit.) results. I have not seen anything like the
structures described by Ussow in any of the species examined by me.

Seen from the surface with the naked eye, the organs appear as dark spots with
whitish centres. With a magnifying glass circular and oval patches of this kind can be
distinguished. In section series we observe the following structure.

The whole organ evidently consists of two parts (PI. LXIX. figs. 2, a, 3, 4 ; PI. LXXI.
fig. 32), an interior regularly spherical and an exterior cup-shaped part. The whole is
exceedingly regular and appears as a rotation body round an axis, the leading lines of
which form three-quarters of a circle for the interior part and a parabola for the external
cup-shaped part.

The axis of this organ is mostly vertical to the surface as in Astronesthes (PI. LXIX.
fig. 3), or oblique, and inclined to the surface at an angle of 30° as in Opostomias
micrijmus.

In the latter case the cup-shaped part, which is a rotation-paraboloid, appears cut oflF

obliquely.

In the first case the organ appears, when seen from the surface, circular, in the second
elliptical, otherwise there is no difi"erence between the vertical and oblique composite
phosphorescent organs.

These organs are of pretty uniform size. Usually those at the anterior ends of the

1 M. Ussow, loc. cit. ■ F. Leydig, Die augeniilinlichen Organe der Fische, pp. 22-24.

294 THE VOYAGE OF H.M.S. CHALLENGER,

rows, on the head, &c., are slightly larger and more conspicuous than the others. The
average measurements are : —

Radius of spherical portion.

0'15 mm

Radius of stricture,

0-08 „

Depth of cup,

■ 0-4 „

Radius of orifice of cup,

. 0-25 „

Focal length of the paraboloid

reflector.

. 0'08 „

They are accordingly larger than the simple organs, yet much smaller than the much
more highly differentiated composite phosphorescent organs, with reflectors, found in
Argyropelecus, Scopelus and Sternoptyx. They are intermediate between these two
kinds in size and differentiation of structure. The whole organ is covered, with the
exception of the exposed outer surface, by a dense layer of pigment very similar to that
described above as forming the sacs which enclose the simple phosphorescent organs.
This layer is about 0"02 mm. thick, and it is most dense at the stricture ; round the
lower spherical part its thickness is greater than in the wall of the cup. Towards the
margin (PL LXIX. fig. 3) it becomes very much thinner. This pigment is the same as
that in other parts of the skin. There is a layer of pigment just below the outer surface
and there are thin layers of it parallel to the outer surface further down which join the
pigment coat of the phosphorescent organ. The nerves and bloodvessels penetrate the
pigment coat. A thin but very distinct membrane (PI. LXIX. fig. 3, m) is found within
it, which clothes the whole of the inner surface of this coat It is very thin, being
only 0"0015 mm. in thickness, but it is conspicuous in sections in consequence of its high
refractive power ; it replaces functionally the complicated reflectors observed in the
more highly differentiated phosphorescent organs.

The outer surface is closed by a continuation of the ordinary cuticle, which is convex
(PI. LXIX. fig. 3, h) and appears as an immovable cornea. Below this, two other
thin membranes are found, the outer one of which is structureless like the cuticle, whilst
the inner one consists of cells (PL LXIX. fig. 3). In the specimens at my disposal, these
membranes were generally folded and appear collapsed, but it seemed to me that in
the living state the space between the innermost and intermediate membrane (PL LXIX.
fig. 3, (i) is probably fiUed with a kind of corpus vitreum, traces of which have been
observed by me in some of the sections. In that case this structure would be a lens.
Its development, however, seems subject to specific variations. Ussow ' in his figure of
the organ in Stomias anguilliformis indicates a structure corresponding to that observed
by me particularly in Astronesthes niger. I am not prepared to say to what extent the
difl"erences between these structures in difierent species may be due to differences in
the state of preservation of the various specimens.

1 M. Ussow, he. cit, pi. ii. fig. lOB.

REPORT ON THE DEEP-SEA FISHES. 295

The cellular membrane below this supposed lens is 0-008 mm. thick, and composed of
one layer of polygonal cells. This membrane extends, like the two preceding ones,
beyond the orifice of the cup on every side for some distance down its sides ; nuclei can
be discerned in it after stainino-.

The light-reflecting memljrane which divides the internal portion from the pigment
coat is continued over the outer surface in the shape of a very fine, circular, watch-glass-
shaped membrane, apparently dividing the thick cellular membrane from the interior of
the phosphorescent organ.

It appears from this that — at least in Astronesthes — there are four membranes outside
the phosphorescent organs, as follows : —
Outermost, continuation of cuticle.
Second, convex structureless membrane.
Third, cellular membrane divided by a large space from the former, which is

supposed to be occupied by a corpus vitreum in the living state.
Fourth, continuation of the special membrane of the organ.

The supposed lens would be concavo-convex, the convex surface having a shorter
focus than the concave one. The action of it on light would therefore be equal to thp
action of a plano-convex or biconvex lens with a focal length equal to the difierence
of the focal lengths of the two surfaces of this structure.

The internal part, invested on all sides by the thin special membrane, is of a very
complicated structure. I have referred above to the results of the studies of Ussow and
Leydig on this subject, but as my own results difier from these very much in some
respects, it will be necessary to describe these structures, as seen by me, in detail.

The internal spherical portion is occupied by radial, pyramidal, closely-packed and
flattened gland-tubes, and in the centre of this part there is a space, as in the
similar simple organs, into which the gland-tubes open.

The gland-tubes correspond to Ussow's " KristaUstabchen," and the empty space in
the interior to the lower extension of his "lens"' of Chauliodus sloanei.

Leydig's representation of the organ oi Ichthyococcus ovatus^ corresponds well with
my own results, and in the four species possessing such organs examined by me this
structure is identical.

The gland-tubes are formed of very fine membranes into which blood-vessels extend,
and are 0-02 mm. wide at the base. The central space — the lumen of the gland — is
about O'l mm. wide, and extended in a plane parallel to the surface.

The gland-tubes are filled with spherical granular cells similar to those described above
from the gland-tubes of the simple phosphorescent organs.

The gland-tubes are closed at their distal ends by convex membranes projecting

' M. Ussow, loc. cit., pi. ii. fig. C.
' =* F. Leydig, Die augeniihnliclien Organe der Fische, pi. \i. fig. 33.

296 THE VOYAGE OF H.M.S. CHALLENGER.

centrifugally, but these do not reach to the investing membrane. They are, moreover,
divided from it by a layer of cells and fibres 0"024 mm. in thickness.

There is a single layer of irregular cells with an average diameter of O'Ol mm.
(PL LXXI. fig. 33, c) lying close to the inner surface of the membrane (b). Their
nuclei are conspicuous, spherical, and can be readily stained. Between and over these
cells, which are divided by small intervals, fine_ fibres running in all directions (PI. LXXI.
fig. 33), are found together with numerous bloodvessels. These fibres extend up into
the partitions dividing the lower portions of the centrifugal parts of the gland-tubes
from each other.

With a low power this layer of cells and fibres appears as a granular zone
(PI. LXXI. fig. 32). It corresponds to that of Chauliodus sloanei figured by Ussow
{loc. cit.) in fig. 7, pi. ii. Above the central space or lumen of the gland,
which is usually occupied by the granular non-transparent secretion, a disc, which
deserves particular attention, is situated, and occupies the whole of the constriction,
and in this way completely divides the contents of the spherical from those of the cup-
shaped part of the organ. It is 0'16 mm. broad, circular, expanded in a plane vertical
to the axis of the organ, and 0*1 mm. thick. The upper external surface is flat, whilst
the lower surface, looking towards the interior of the spherical part, appears slightl}^
convex and projecting in the centre into the lumen of the gland (PL LXIX.
% 3).

This disc is divided by a kind of diaphragm, which is not very distinct, into two
portions, an external and an internal. The diaphragm appears as a continuation
of the inner membrane, stretched out within the projecting ring of the incision which
divides the cup-shaped from the spherical portion of the organ.

The whole of the disc is composed of large irregular cells, which readily become
stained and contain large spherical nuclei, O'OOS mm. in diameter, which then appear
exceedingly prominent. Although the contours of the cells are not very distinct, I have
been able to see them in the organs of all the specimens examined by me.

This double disc of large cells is very conspicuous ; it corresponds, as far as its position
is concerned, with Ussow's^ "lens." Leydig^ represents it as a portion of the granular
secretion occupying the lumen of the gland.

The space above this disc — the cup — is filled with a somewhat granular substance in
which radial lines are very clearly visible with a low power (PL LXXII. fig. 32). A similar
radial structure has been observed in this part of the organ by Ussow ^ and Leydig * ; but
while the former supposes it to be caused by irregular threads pervading the structureless
substance filling the cup, the latter sees in it the expression of radial gland-tubes
similar to those found in the lower spherical portion of the organ.

1 M. Ussow, loc. cit., pi. ii. fig. 6 k, I. - F. Leydig, loc. cit., pi. vi. fig. 33.

2 M. Ussow, loc. cit., pi. ii. fig. 6, x. * F. Leydig, loc. cit., pi. vi. fig. 33.

REPORT ON THE DEEP-SEA FISHES. 297

There can be no doubt that these structures in the species examined by me are in
no way similar to those described by Ussow ; I find, however, a dift'erence between them
and the gland-tubes of the internal spherical part, which has not been noticed by
Leydig.

At first sight it appears that the radial lines in the part occupying the cup are much
closer together than in the interior of the sperical portion of the phosphorescent organs.
Spherical cells, as in the latter part, cannot be distinguished so readily in the cup, and
the substance also seems to he more transparent and less granular. The radial strijies are
much closer together in Echiostoma than in Astronesthes.

The structure of this part of the organ is the following : —

From the disc of large granular cells, situated at the constriction, fibres originate,
which extend upwards in a vertical direction towards and nearly to the outer surface,
terminating 0"04 mm. below it.

They extend below to a trumpet-shaped, thickened base, and become more and more
slender distally. They are in direct connection with the substance of the basal disc, and
interspersed with granular spindle-shaped cells which appear more abundant in the basal
tlian in the distal part of the fibres. These spindle-shaped cells have spherical nuclei
identical with the nuclei in the cells of the disc. The bulk of the fibres seem to be
composed of nerves ; bloodvessels have not been observed in them.

The fibres are on an average 0-025 mm. apart. Their structure is very transparent
and they appear closer than they really are in longitudinal sections, because one generally
sees several layers of them, but transverse sections show their true distance.

Attached to each of these fibres are cells, generally long and slender but sometimes
also stout and spindle-shaped, in such a way that one layer of them encloses each fibre.
These cells appear to be attached to the fibres by one of their ends and they project from
the fibres like the hairs on the tail of a squirrel. Sometimes, particularly when the cells
are very slender, they extend nearly parallel to the fibres and produce the closely striated
appearance of this structure which is observed in some cases (PI. LXXI. fig. 33). Some-
times, particularly where the cells are stout, they radiate from the fibres in an oblique
direction, never exceeding an angle of 45°, and they invariably point outwards.

These cells are very tender and transparent, their- nuclei easily escape observation
in specimens not specially preserved, and theii' contours can only be distinguished l)y
means of very fine sections and good lenses. Under ordinary circumstances this whole
mass appears structureless and granular.

If we now compare this description with the statements of Ussow and Lcydig,
mentioned above, we find that although the differences are great, still the observations
are not altogether incompatible.

Ussow's observation of the organ in the fresh state in Chauliodus shows. us that
there is a transparent substance with radial lines in this part of it.

(ZOOL. CHALL. EXP.— PART LVII.— 1887.)

298 THE VOYAGE OF H.M.S. CHALLENGER.

It appears highly probable that the whole structure is very transparent in the fresh
state, and that the delicate cells, which appear granular in spirit specimens, are then
difficult to distinguish. Perhaps Ussow has failed to see their contours and nuclei. The
radial fibres described by him entirely correspond to the fibres observed by me.

Leydig represents this structure in his figures as consisting of radial tubes, which he
considers as glandular.

Between the squirrel-tail-like columns of cells with the central fibre, very slender
membranes, likewise containing nerves as well as capillaries, are found. These membranes
coalesce with the watch-glass-shaped external portion of the membrane and are thickened
near their base. They divide the fibres with their cell columns completely, as may be
observed in longitudinal, but much better in transverse sections which are properly
stained.

These polygonal tubes are identical with the tubes observed by Leydig and are not so
distinct as the gland-tubes of the spherical part, but similar to them.

Ussow has not observed them, whilst Leydig and myself have found them without
exception. According to Leydig, however, they are filled with spherical granular cells,
similar to those in the proximal spherical portion of the phosphorescent organ. Leydig's
material was not very good and this statement must therefore be accepted with caution.

c. Innervation.

Leydig^ has discovered the mode of innervation of these organs. According to him,
a thick nerve enters it by penetrating the pigment coat and intima, near the central
constriction, which divides the spherical from the cup-shaped portion. It then spreads
out and joins the granular mass in the centre.

To these observations, which I can corroborate, I have to add that the nerve is a
branch of a spinal nerve, and where there are two composite organs on each side of each
segment, the nerves supplying them join a little way above the upper organ of the two.
They are the thickest branches of the spinal nerves, and all other branches originate
from them in such a way as clearly to indicate that they form the stem of the distal
two-thirds of the spinal nerve. The two composite phosphorescent organs appear to be
situated at the terminations of the two main branches into which the spinal nerve
divides.

I have mentioned above that Leydig's " central granular mass " is identical with the
granular secretion in the centre of the spherical glandular portion, together with the disc
of large granular cells situated in the constriction. The nerves of course terminate in,
the disc, and not in the secretion. Here they become non-medullated. Other, but very
much smaller and quite insignificant nerve-fibres are also found attached to the sphericid

' F. Leydig, Die augenalmlichen Organe der Fische.

REPORT ON THE DEEP-SEA FISHES. 299

part. There are generally two or three such nerves, which apparently have nothing to
do with the large nerve supplying the central disc.

Ussow's representation of the innervation of the organs in Stomias anguilUfoi'mis,
where a single nerve is said to enter at the back of the spherical part, does not coincide
with Leydig's observations or my own.

The innervation of these organs corresponds to that of the simple phosphorescent
organs above described, and in every case the nerves supplying them are branches of
spinal nerves.

d. Function.

It is not very difficult to perceive the functions of the different parts of these
organs. The pigment coat prevents the light from issuing in any other direction than
that indicated by the axis of the organ.

The membrane which reflects the light produced within the organ is, in con-
sequence of its shape, very well adapted for the purpose of concentrating the light in
one cone.

The optical action of this reflecting membrane is illustrated in PI. LXIX. fig. 4.
The spherical part reflects all the rays of light which are thrown in a centripetal
direction, until they pass from it into the cup-shaped portion. As the cup has the
shape of a rotation-paraboloid, all the light which issues from the focus of the parabola
will be reflected parallel to the axis of the optical system, whilst light coming from other
points in the neighbourhood of the focus will be reflected in a more or less simdar
direction, so that all the light produced within the organ issues from it in the shape
of a cone, the axis of which is the continuation of the axis of the optical system. The
light passing through the concavo-convex lens is further concentrated and may be emitted
from the fish as an intense flash in the direction of the axis.

There are muscles surrounding these phosphorescent organs, but it is doubtful
whether the organs are movable. If they were, the, fish could of course throw flashes of
light from them in any desired direction, and by setting tlie axes of aU the organs
of one side in the same direction, might produce a. " broadside " of light-flashes
sufficient to illuminate objects at some distance.

There can hardly he any doubt that the spherical part of the orgtm is filled \\ith a
glandular structure. The cells of the layer found just wdthin the membrana propria are
probably ganglion cells in connection with the nerves which supply this part of tlie
organ. The gland-tubes are morphologically very similar to tliose in the simple organs,
and produce a granular secretion by the same process of direct conversion of cell-
substance into secretion. The secretion accumulates in the space below the disc, and the
disc itself is evidently composed of ganglion cells, which are in connection with the large
nerve, to be designated after its discoverer, Leydig's nerve.

300 THE VOYAGE OF H.M.S. CHALLENGER.

The really phosphorescent apparatus is to be sought in the cells which occupy the
■cavity of the cup, and which are evidently connected with the ganglion-cells by means
of the radial fibres issuing from the disc.

The structure is intermediate between the simple form in the simple ocellar
phosphorescent organs and the more complicated structure of the composite organs with
special reflector, to be described below.

The fish can at its option incite the organ, which under ordinary circumstances
is non-luminous, to phosphorescence. The voluntary impulse is transmitted by the
thick nerve of Leydig to the disc of ganglion cells, which excite the phosphorescent cells
in the cup to action by means of the radial nerve-fibres.

The phosphorescence of the latter requires, however, the secretion of the gland in the
sphere as fuel, in a manner similar to that which has been described in the simple organs.

The secretion passes through the disc and the radial fibres to its destination, where
it is consumed to pi'oduce light.

e. Development.

Although no transitional forms have been observed by me, I do not doubt that these
composite phosphorescent organs have been developed from the simple ones by continued
differentiation of the parts. During this progress of development the shape, which is
very varialile in the simple organs, has been determined. Their number has been
reduced and likewise determined, together with their position. From a great number of
undiff"erentiated organs scattered irregularly over the surface of the body, a small
number of more highly difierentiated organs, with a definite position, has been
evolved.

4. Composite ocellar organs, with special reflector.

a. Distribution.

These most highly differentiated phosphorescent organs have been found by me ia
Argyroixlecns Jiemigymnus, Sternoptyx diaphana, and Scojpelus henoiti, whilst Ussow '
lias seen them in Argyropelecus hemigymmis and designates them as " dritsenahnliche
Organe." Leydig,^ who designates them as " glasperlenartige Organe," has found them
in Gonostoma demidatum, Argyropelecxis hemigymnus, Scop)elus rissoi, Scopeliis huin-
holdtii, Scopehis henoiti, Scop>eli(s J>onap>artii, Scopelus rafinesquii, and *Scopc/».s-
meto2)oclam2ms.

The number of these organs and their distribution on the body are very regular, and

' M. U.ssow, loc. cit., p. 108. - M. Ussow, loc. rit.

REPORT ON THE DEEP-SEA FISHES. 301

as they are large and striking in ai^pearance, they strongly (;haracterise the species which
possess them.

In the diflFerent species they are distributed as follows :—

Argyropelecus hemigymmis. — A row of six anterior to the pectoral fin, a row of
twelve ventral, close to the median plane of the body, and three groups on the sides,
ill the vicinity of the anal fin. The groups are formed by the breaking up of the two
lateral rows of phosphorescent organs observed in other fishes, the upper row furnishing
three, and the lower two groups. All the organs point downwards.

Sternoptyx diaphana. — A row of nine large organs on the ventral side, close to the
median plane, representing the lower row, and two groups of three organs in each, above,
on the side, representing the upper row (PI. LXX. figs. 15, 17). All point downwards.

Scopelus henoiti. — One organ in the middle of the back, behind the dorsal fin,
pointing backwards. The organs of the lateral rows have retained their original shape
and distribution.

Scopelus, otlier species. — I cannot give an account of the distribution of these organs
in other species, as Leydig does not specially mention these peculiar unpaired organs
behind the dorsal fin which are so characteristic of Scopelus. Sometimes there are more
organs than one in that locality, in some species as many as five, one behind the
other, and they always point backwards.

Gonostoma denudatum. — In two lateral rows like the composite organs without
reflectors (Leydig).

h. Structure.

a. General.

The structure of these organs is more comjjlicated than that of the organs without
reflectors, and there are very essential differences between the two, although they are
similar to a certain extent in shape, and formed on the same principle. They may be
single and isolated, as for instance the organs on the back of Scopelus henoiti, here
designated "stern-chasers"; the rule, however, is that several are placed together, with
their sides in contact, and that theii- spherical interior portions coalesce to a certain extent.
Buch a coalescence of course produces a canal, from the outer side of which the cup-shaped
portions of the organs project (PI. LXX. figs. 17, 18, 20). Such structures are never
produced by the union of phosphorescent composite organs without reflectors. These
organs with reflectors are always very oblique, so much so that the axis is inclined
towards the surface of the fish at an angle, never exceeding 10°. Generally this angle
is smaller and the axis often appears nearly parallel to the surface. The spherical
portion is more elliptical than in the organs above described, and appears sac-shaped.

302 THE VOYAGE OF H.M.S. CHALLENGER.

The parcaboloid cups are in a very slanting position. And as they meet the
surface very obliquely, the outline which is the intersection of the cup, and the surface
appears as a very elongate ellipse. The ventral organs which lie at the extremity of
the body in the median line have a circular outline, because they are situated close
to the ventral margin of the laterally compressed body.

These ellipses are very conspicuous ; they apjjear surrounded 1)y a dark line of
jiigment, whilst they shine with a brilliant silvery lustre in the centre. They measure
1 to 2 by 3 to 6 mm. in diameter. A dark mass — the pigment coat of the sac-shaped
portion — is attached to one end and looms through the semitranspareut skin of the fish.

The two rows of ventral organs of Argyropelecus and also of Sternoptyx approach eacli
other so closely in the median line of the body that they are nearly in contact (PI. LXX.
fig. 17). Their orifices (PI. LXX. fig. 19), therefore, appear nearly square, the cups
becoming by mutual compression prismatically four-sided in their outer portions.

In external appearance there is a great difference in these organs, although the
internal structure is the same in all. Four varieties may be distinguished.

(1) The organs of Gonostoma.

These have been studied by Leydig.^ I have not seen any specimens of this genus ;
but they do not coalesce like the other varieties and resemble more the composite
phosphorescent organs without reflectors. They are smaller than the other varieties
and not so oblique. Leydig gives no detailed description of their shape.

(2) The dorsal organs or "stern-chasers" of Scopelus.

The sac-shaped portions do not coalesce, and the constriction dividing the sac-
shaped and cup-shaped portion is very conspicuous, it is circular and has a diameter
of 0"3 mm. The axis is nearly parallel to the surface. The cup-shaped portion is a
rotation-paraboloid mth very smaU focal length, about O'l mm. The cup terminates on
the surface with a very elongate, elliptical contour measuring 1 by 4 mm., and the posterior
margin approaches the constriction to within 0'2 mm. The sac-shaped proximal part (if
the organ is elongate, conical, tapering towards the rounded end, and widest just l^elow
the constriction, where it has a width of nearly 1 mm. It is 2*5 mm. long.

The sizes vary according to the species ; the more numerous these stern-chasers are,
the smaller they appear to be. The largest are possessed by those species which have
only a single one.

The propoi'tions are always as indicated by the above numbers, and the shape of
the organ is constant.

' F. Leydig, he. cit., ji. 12.

REPORT ON THE DEEP-SEA FISHES. . 303

(3) The groups of lateral organs in Argyropelecus and Sternopt;/x.

These groups consist of from three to five organs, the sacs of which coalesce.
Generally there are three (PI. LXX. figs. 22, 23, 24). The constriction is circular and
has a diameter of O'l mm., and the plane in which it lies is perpendicular to the axis.
The axis is nearly parallel to the surface. The cup-shaped portions are rotation-
paraboloids, and the line with which they terminate on the surface of the fish is a very
elongate eUipse measuring 1 "5 by 5 mm. This circumference touches the constriction,
that is to say, only one side of the cup, namely the lower, is developed (PI. LXX.
fig. 23). The focal length of the paraboloid is O'l mm.

The sac-shaped portions of the organs coalesce to form an irregular flattened sac,
with from three to five circular apertures on one side, the original strictures of the
organs.

Seen from the surface this combined sac is in the triplex organ of Sternoptyx nearly
semicircular (PI. LXX. fig. 22). In sections its flattened shape becomes apparent (PL
LXX. fig. 23). It measures 0'3 mm. in height and 1'2 mm. in length. The width of
course depends on the number of cups attached to it. In the triplex organ it is about
1"2 mm., in the quinquei^lex 2 mm. In the interior of it crests or ridges can be discerned
which are the remnants of the partitions between the adjacent phosphorescent organs,
the internal portions of which have coalesced.

(4) The ventral rows of Argyropelecus and Sternoptyx.

Wherever composite ocellar phosphorescent organs are observed, they invariably form,
as stated above, two lateral lines or rows on each side of the body. The groups of
triplex and quinqueplex organs of Sternoptyx and Argyropelecus mentioned above,
belong to the upper of the two rows which is split up to form groups along the side of
the fish.

The lower rows, however, remain unbroken and continuous. They approach each other
very closely (PL LXX. fig. 17). The lower portions of the organs on both sides coalesce
to form one large ventral canal lying in the median line of the body, from the lower side
of which two rows of cups project (PL LXX. fig. 20). The optical axes of all the cups are
parallel, and so the rays of light from all these cups are concentrated in one direction.

/8 Histology.

The histological structure of the diff"erent organs belonging to this grouj) is ].retty
much the same, so that it can be dealt with in a summary manner.

804 THE VOYAGE OF H.M.S. CHALLENGER.

The composite ocellar organ with reflector consists of three distinct layers ; an outer
layer of pigment, an inner coating of light-reflecting threads or spicules, and a transparent
soft mass in the interior.

The pigment layer encloses the proximal portion and also extends distally with
undiminished thickness to the margin of the cup (compare PL LXX. figs. 17-24 ; and
PI. LXXII. fig. 44). It consists of dark brown or black pigment-granules closely packed
in the connective tissue.

The reflecting layer, which is perforated and traversed by bloodvessels and nerves
leading into the interior of the organ, is very thick and hard. In some cases pigment-
granules are found in the course of the bloodvessels and nerves in the perforations
through this layer. Such are figured by Emery,^ and have also been found by me iu
some cases, and Leydig " records them in the case of Scopelus.

The light-reflecting layer is composed of calcareous spicules which vary exceedingly
in size. They are generally very thin, and may be very long and filiform, or shorter,
only about fifteen times as long as thick and abruptly pointed at each end, as in
'Argyropelecus. They are closely packed, generally parallel, and are disposed longi-
tudinally, extending from the base of the cup to the margin in meridional lines.
The spicules are not round, cylindrical, but prismatic, with plane surfaces and accurately
apposed to one another, there being hardly room for any substance between them. This
intervening substance forming the thin sheaths of the spicules appears as connective
tissue. The optical efi"ect of this structure is very remarkable, its lustre being very
brilliant in consequence of the flatness of the surfaces of the spicules.

The structure which occupies the interior of these organs, however, demands our
special attention. In the proximal sacs of the complex and the solitary organs, and also
in the large ventral canal of Sternoptyx, a glandular structure is met with. This consists
of tubes which extend more or less longitudinally throughout the ventral canal of
Sternoptyx (PI. LXX. fig. 20), and which appear radially situated in the other cases
mentioned above. In these (PL LXX. fig. 23) the gland-tubes are conical, attached to
the wall of the sac by their broad base, and opening at the narrow end which lies just
below the mouth of the sac.

These tubes are formed of a fine membrane into which bloodvessels and nerves
extend, and are lined by a single layer of highly granular gland-cells, which appear about
as broad as high. The lumen is generally occuj)ied liy a granular substance which
may be stained very readily, and which appears to be mucus, jirecipitated by the action of
spirit. The gland-tubes in the ventral canal of Sternoptyx seem' to open below the
bases of the cups in the corresponding position. These gland- tubes do not occupy the
whole of the sac, there being an empty space just below the mouth of the sac into which

' E. Emery, Mittheil. aus d. zool. Station zii Neapel, Bd. v.

- F. Leyuig, Die augenalnilichen Organe dur Fische, pi. x. fig. 60

REPOET ON THE DEEP-SEA FISHES. 305

they pour their secretion. Here large and conspicuous spherical bodies (nuclei ?)
which very readily become stained are found, surrounded by the secretion of the gland-
tubes (PI. LXX. fig. 23, c).

It appears from this that these structures are very similar to those described above
from the proximal sac of the regular, vertical, composite organs without reflector.

The structure of the substance which occupies the distal portion of the organ or the
cup, is very different and complicated.

The bloodvessels and nerves which pass through the spicule-layer extend perpendi-
cularly to the surface. They are straight and sometimes supported by a slender carti-
laginous rod, and end just below the outer surface (PI. LXXII. fig. 44). Leydig' and
Emery ^ describe and figure these vessels as irregularly curved and branched, but in all
the specimens examined by me they were quite straight. From these vertical columns
slender cells radiate, which are about half as long as the vertical bloodvessels are apart.
They extend tangentially from their lower portion and radiate from the upper end in
every direction, and since they are closely packed they surround the vertical vessels on all
sides. In this way cylindrical or prismatic structures, rounded at their distal ends, are
produced, which measure about 0'2 mm. in diameter and are 0'8 mm. high. These
cylinders do not occupy the whole of the space, and do not touch each other, but
appear to be separated by a substance which forms narrow partitions between the
cylinders and which covers their rounded distal ends. This substance is granular and
contains round nuclei which stain very readily. Outside there are one or more layers of
very flat epithelial cells covering the whole organ.

The elements which compose the cylinders are of particular interest (PI. LXXII.
figs. 43, 44). There are two kinds of cells in the radiating mass which surrounds the
vertical pillars, the greater number being faintly visible and indifferently spindle-shaped or
cylindrical (PI. LXXII. fig. 43, a). Other very peculiar club-shaped elements are found
between them (PL LXXII. fig. 43, h), these widen towards the distal end and taper
proximally to form a very long and comparatively slender peduncle which is about one-
fourth as thick as the club-shaped end. In the latter an oval highly refracting body
(PI. LXXII. fig. 43, c) is situated, which apparently consists of a cavity, with a very fine
wall, containing fluid. This vesicle occupies the greater part of the clul)-shapcd end
of the cell and is surrounded by a thin film of protoplasm only. Just below it the oval
nucleus is situated. The protoplasm of tliese cells as well as the nucleus stains very
readily.

The appearance of thin sections renders it probable that the proximal peduncles of
these cells are in direct connection with the nerves, which extend upwards in the central
piUars of the cylinders.

1 F. Lej-dis, Die aiigenahnliclieii Organe der Fische, pi. x. fig. 60.
,,- E. Kraery, Mitiheil. aus d. r,oot. Station xu Xeapcl, Bd. v.

(ZOOL. CHALL. EXr. — PART LVII. — 1S87.) '^'1 3^

S06 THE VOYAGE OF H.M.S. CHALLENGER.

I think that these cells are the special phosphorescent elements. I have found the
same cells in a good many other kinds of phosphorescent organs of fishes, but not in
all of them.

c. Innervation.

According to Leydig ^ thick nerves extend through the superficial tissue of the fish
below these organs, and give ofi" stout branches, which enter the proximal, sac-shaped,
glandular portion from the side.

According to my own observations the nerve enters at the incision between the sac-
shaped and distal cu^D-shaped parts and extends principally below the S2)icule-layer under-
lying the latter; there the nerve fibres form a very conspicuous plexus (PI. LXXII.
fig. 44, g) which occupies the space between the continuous pigment-layer and the light-
reflecting spicule-layer.

From this plexus nerves are given off" which, together with bloodvessels, traverse
the organ perpendicularly from the bottom to the roof, extending upwards in the
central pillars of the cylinders of radiating cells described above. They are, as stated,
probably in direct communication with the typical phosphorescent clavate cells.

According to Leydig^ the nerves form a plexus loithin the phosphorescent tissue in
the organs of Scopelus humholdtii.

d. Function.

Regarding the function of these organs, we are in a more fortunate position than in
regard to most of the other structures described in this Appendix, inasmuch as direct
observation has shown that these organs actually emit light, so that there can be no
doubt about their phosphorescent nature.

Willemoes Suhm^ says that a Sco2)elus bi'ought up by the trawl at night " shone like
a star in the net." Guppy* and Giinther have made similar observations. Gupp)'^
particularly was able to observe that the light is emitted y^-om these organs.

It seems not improbable that the glands in the sac-shaped proximal portion of these
organs produce a secretion which is poured out into the cup-shaped distal part, and there
a mutual chemical action between this slime, in which also cells and nuclei are found,
and the tjrpical phosphorescent clavate cells may take place at the will of the fish, and a
certain amount of light may be produced, which is reflected by the parabolic spicule-layer,
and thrown out as a strong flash.

The ventral organs can illuminate the dark water below the fish for any purpose,

' F. Leydig, Die augenahiilichen Organe der Fische.

- F. Leydig, loc. cit., pi. x. fig. 60.

3 Willemoes Suhm, Clialleiiger-Briefe, Zeitschr.f. wiss. Znol., Bd. .\xiv.

•• Guppy, Ann. and Mag. Nat. Hist., ser. 5, vol. ix. '

REPORT ON THE DEEP-SEA FISHES. 307

whilst the dorsal stern-chasers or the solitary dorsal stern-chaser, which are invariably-
directed backwards, probably serve for purposes of defence, inasmuch as a strong ray of
light shot forth from the stern-chaser may dazzle and frighten an enemy which is in hot
pursuit of a Scopelus.

('. Development.
•According to Emery' these organs are enclosed between two scales, one forming the
light-reflecting layer of spicules below the cup-shaped portion, and the other a lens
on the surface above it.

All these organs examined by me are destitute of a lens, and only covered by a very
thin epithelium.

As these organs, with the exception of the dorsal stern-chasers, are always found in
two more or less continuous lateral rows, they seem to be in some way connected with the
slime-canal system.

It may be supposed that the stern -chasers have been developed in the skin inde-
pendently of the lateral slime-canal.

The development of the complex organs with coalesced proximal portions from
isolated ones, has been referred to above.

5. Regular ocellar projecting organs.

a. Distribution.

These organs have been only found in Xenodermichthys nodulosus.
They differ in a remarkable manner from all other forms, and no organs similar to these
have been previously described.

They are found segmentally placed in rows on the sides of this fish.

h. Structure.

These organs appear as oval bodies, attached to the fish only by a small portion of
their base, and they project freely beyond the surface, difi"ering in this respect from all other
analogous organs. Each organ is oval, about two and a half times as long as high, slightly
flattened, and broader than high. One end is slightly wider and covered by a thick layer
of pigment. This is directed dorsad, and is accordingly under ordinary circumstances
turned upwards, while the other end is slightly narrower and looks downwards, Ijciug
situated ventrally. This end is only covered l)y a thin transparent epithelium. The
organ is about 2 mm. long and 1 mm. wide ; it is attached (PI. LXXIII. fig. 50) to the
surface of the fish by a peduncle near its upper end, and apparently pendent from the
base of attachment.

' C. Emery, Mitiheil. aus d. zool. Station zu, Neapel, Bd. v.

308 THE VOYAGE OF H.M.S. CHALLENGER.

Externally the organ in its dorsal portion is, as mentioned above, covered by a thickly
pigmented shell, which possesses a crest, projecting inwards and dividing the contents of
the organ into a proximal and distal portion. In this respect this organ appears as a
transition between the simple and composite ocellar organs. The side which touches the
fish below the base of attachment likewise possesses a thick layer of pigment (PI.
LXXIII. fig. 50, g). In the lower end a few superficially situated patches of pigment are
found (PI. LXXIII. fig. 50, k). The proximal portion, which corresponds to the sac-
shaped part of the composite ocellar organs, is occupied by a mass, which is readily stained,
and which contains numerous conspicuous nuclei. The distal portion is filled with
elongated cells, which extend parallel to the long axis of the organ, and accordingly point
downwards ; these cells are very similar to those of the cup-shaped portion of the
composite ocellar organs described above. We find, namely, slender spindle-shaped cells
(PI. LXXIII. fig. 51), and the typical phosphorescent clavate cells (PI. LXXIII. figs. 52,
53, 50, i), the club-shaped ends of which are situated distally. They do not form one
single regular layer, but are scattered throughout the whole of the distal portion of the
organ. The vesicle which reflects the light sometimes appears to be divided into two
portions (PI. LXXIII. fig. 53), but generally it is simple and oval, like the vesicles
described above.

c. Innervation.

A very stout nerve enters the organ at the base of attachment and extends into the
proximal portion (PI. LXXIII. fig. 50, f, h). A direct connection of this nerve with
the typical clavate cells is highly probable.

d. Function.

Within this organ no glandular portion can be discerned, but it seems not improbable
that the secretion of the slime-canal system may pass into the organ. There can be no
doubt that the typical clavate phosj)horescent cells are the light-producing elements of
the organ.

e. Development.

It appears that these organs are developed in a similar manner to those sunk in the
body, which have been described above. The peculiar structures of the same fish,
which are described below, may throw some light on the origin of these organs from the
slime-canal system.

f. Doubtful structures in the skin.

On the sides of the body, in close proximity to the organs described above, we find
thickenings of the fibrous dermal layer, which lies outside the thick pigment-stratum

EEPORT ON THE DEEP-SEA FISHES. 309

of the skin (PI. LXXIII. fig. 49). Ducts leading from the slime-canals of the skiu to the
outer surface pass through it, and form loops in the fibrous tissue, which is apparently
quite transparent. It seems not improbable that the contents of these ducts are
luminous.

6. Regular ocellar covered organs.

a. Distribution.

These organs are found iu Halosaurus macrocMr and other species of Hcdosaui-us.
They invariably form one single row on each side of the body, overlying the large lateral
slime-canal. The scales of the lateral line are, in these fishes, much larger than the rest
and form a conspicuous row on each side. They are covered by memliraues. Each
scale bears a transverse vertical ridge on its outer side, and behind this ridge a conspicuous
spindle-shaped whitish organ is situated, which is 1 mm. broad and from 2 mm. to 3 mm.
long. The ends are extended to form fine points. The long axis of the organ is vertical.

h. Structure.

a. General.

The large scales of the lateral line overlap about one-third or less, and appear slightl)'
curved, S-shaped in longitudinal section. Outside, the row of scales is covered by two
membranes, the outer one of which appears pretty continuous and attached particularly
above, and loose only partially on the lower margin. The inner one extends from ridge
to ridge of the successive scales (PL LXXIII. fig. 61, r). The lateral slime-canal is situated
l)elow these scales and sends l^ranches up between them, which extend on the outer side of
the proximal, anterior portion of each scale (PI. LXXIII. fig. 61, e). The space between
the slime-canal and the scales is filled with a peculiar tissue (PI. LXXIII. fig. 63, c), and
this extends outwards so as to fill the spaces between the scales ; this tissue will be
described below. At the sides of the slime-canal meandriform gland-tubes are met
with (PI. LXXIII. figs. 50, h, 59). The whole of the immersed portion of the scale is
covered by a pigmented membrane (PI. LXXIII. fig. 61, m). Between the pigment coat
and the tissue underlying the scales a highly refracting membrane is observed. Just
behind the transverse ridge a peculiar, apparently phosphorescent organ is attached out-
side to the middle of the scale ; this is spindle-shaped and upright, and measures 1 mm.
in width and 2 to 3 mm. in length in the vertical direction, being about 0*4 mm. high
(in spii-it specimens). Below this phosphorescent organ the scale is perforated by a
conical canal leading outwards and backwards (PI. LXXIII. fig. 61, t). The nerves
and bloodvessels which supply the organ pass through this canal. The phosphorescent
organ itself has a radiating structure.

310 THE VOYAGE OF H.M.S. CHALLENGER.

*
jS. Histology. •

(1) The scales.

The scales have been described by Dr. Glinther elsewhere in this Report, they do not
show any peculiarity so far as their histological structure is concerned.

(2) The pigmented membranes.

The pigment does not form a perfectly continuous layer, but appears in patches, which
lie pretty close together so that these membranes have a dotted appearance. They
surround the scales on all sides (PI. LXXIII. figs. 61, I, m, 62, c,f).

(3) The light-reflecting membrane.

The outermost layer of the scales is a very thin light-reflecting membrane, which
appears in sections as a narrow dark hne only, it is closely attached to the pigment-
membrane below it (PI. LXXIII. figs. 61, n, 62, b,f). When seen from the surface
(PI. LXXIII. fig. 54) it appears to be composed of two systems of very fine parallel
threads crossing each other nearly at right angles. This structure is exceedingly minute
and becomes apparent only under a very high power, and it seems probable that the
silvery lustre which these membranes exhibit is produced by this structure.

(4) TJie phosphorescent organ.

The elongate spindle-shaped phosphorescent organ above mentioned appears to be
connected with the tissue below by a comparatively slender canal, which passes through
an oblique perforation in the scale. It is rich in bloodvessels and consists essentially
of two parts. In the lower portion we find numerous and large bloodvessels, whilst
between these and outside of them very elongate radially extending cells are situated,
which reach from the base of the organ to the surface. Here they are curved so that
their distal portion extends tangentially. These cells are mostly spindle-shaped,
granular, and contain a nucleus in the (centre, and between them comparatively wide
transparent spaces are observed. It seems that these spindle-shaped cells are not in
contact, but divided from each other by a hyaline substance. The outermost layer of the
organs is as usual more granular than the remainder. In the middle of the organ these
spindle-ceUs are vertical to the surface, but near the margin they curve outwards. At
the base of the spindle-cell layer irregular ganglion cells are found. The whole organ is
raised above the surface of the scale, but it is covered and protected from the outside
by the above mentioned membranes.

REPORT ON THE DEEP-SEA FISHES. 311

(5) The slime-canal and its branches.

Below tlie lateral line the slime-canal is situated, and it extends in the usual way
from the head to the tail. It is about 075 mm. wide and regularly cylindrical, with
a more or less circular transverse section. Below the base of each scale it is widened,
the upper side of it forming a low conical extension, from the summit of which a
branch, which extends along the upper surface of the proximal part of the scale,
originates. The lumen of the slime-canal is more or less circular in transverse section,
and lies excentrically very close to the outer surface of the cylindrical structure. It
is about one-third to one-half as wide as the whole organ (PL LXXIII. fig. 55, e) ; at
the bases of the scales where the canal is extended, the lumen also extends (PI. LXXIII.
fig. 61, f/). I have not observed a continuation of the lumen into the branches. The
lumen of the slime-canal is more or less filled with a granular mucin-precipitate, pro-
duced by the action of the spirit, and it is surrounded by the cells of the slime-canal.
Here two distinct kinds of cells are met with. Firstly, irregular, granular bi-, tri-, or multi-
polar cells with large, readily stainable nuclei (PI. LXXIII. figs. 56, 57), and secondly,
short cylindrical elements, with a regularly circular transverse section, transparent con-
tents, a thick and conspicuous cell-wall, and a small shining nucleus. The former are
particularly abundant in close proximity to the lumen, whilst the latter, which form by
far the greater bulk of the whole structure, do not exclusively occur towards the surface,
l)ut are also met with close to the lumen, intermixed with the granular cells (PL LXXIII.
figs. 58, 62, (/). I consider the former to be nervous and the latter glandular. No such
structures as those described by F. E. Schulze ' were observed by me, probably because
the specimens at my disposal were not sufiiciently well preserved.

The branches which extend along the scales (PL LXXIII. figs. 61, e, 62, g) are
composed of both these kinds of cells, the glandular elements being apparently very
prevalent. The branches extend tangentially and coalesce to form a Jiat expanded con-
tinuous layer just above the light-rejlecting membrane over the base of each scale (PL
LXXIIL fig. 62, g).

(6) Tlie tissue overJijing the slime-canal.

The whole of the space between the slime-canal and the scales is occupied (PL
LXXIII. figs. 61, /, g, 55, a, 63, c, 60, 62, o, h, i) by a peculiar structure, which
consists of lenticular bodies of varpng size but of uniform shape, interwoven with a tissue
composed of very fine threads. These lenticular bodies are very large and numerous ;
they extend tangentially and appear spindle-shaped in section (PL LXXIII. figs. 55, 60,
61) because their margin is very thin and tangentially extended. They attain a width

1 F. E. Schuke, Ueber <1ie Siiinesorgane der Seiteiilinie bei Fischen iiiiil Ainpliilniii, Ankiv f. mikrod: Anat:,
IM. vL, 1870.

312 THE VOYAGE OF H.M.S. CHALLENGER.

of 0"2 and a height of 0"06 mm., appearing perfectly structureless, and being formed of
a solid imstainahle yellow substance, which may perhaps be a secretion poured into these
spaces.

The fibrous tissue which separates the lenticular yellow bodies from each other
consists chiefly of slender spindle-shaped elements, with oval, highly stainable nuclei.
There seems to exist a very fine cuticular membrane surrounding each of the lenticular
bodies.

The volume of the fibrous tissue is about as great as that of the yellow substance in
the lenticular bodies.

(7) The meandriform gland-tuhes.

At the sides of the slime-canal (PI. LXXIII. fig. 55, h) large and conspicuous highly
stainable glands (PI. LXXIII. fig. 59), which consist of meandriform tubes of circular trans-
verse section and uniform width, are met with. These gland-tubes, which do not appear
to open into the slime-canal, are comj)letely filled with round cells each of which has a
very distinct cell-wall, a small nucleus, and transparent hyaline contents. They are very
similar to the short oval or cylindrical elements, with circular transverse section, which
are found in the slime-canal (PI. LXXIII. fig. 58).

c. Innervation.

I have mentioned above that I look upon the granular cells in the slime-canal as
ganglion-cells. They are connected by a fine plexus, which extends up along the scales
and supplies the fibrous tissue between the lenticular bodies with nerves. A large bundle
of nerve-fibres, similar to that observed in other cases, is found in these organs in
Hcdoscmrus, in the canal leading from the chamber through the scale into the
phosphorescent organ.

d. Function.

According to F. E. Schulze,^ the slime-canal is to be regarded as a sense-organ,
adapted to perceive vibrations of the water with wave lengths too great to be per-
ceptible by the ear. In other words the slime-canal is a supplement to the ear, and
any further development of it should, one would think, be organs of sense of a similar
kind. In the abysses of the sea, where light is scanty, this organ would be particularly
valuable and so we might assume that here we have a case before us, where the slimo-
canal sense-organ has been further developed and complicated.

The peculiar whitish colour of the organ and the light reflecting membrane which
clothes the chambers might, on the other hand, lead one to assume that these organs really

' Loc. cit.

REPORT ON THE DEEP-SEA FISHES. 313

arc, as is here supposed, phosphorescent ; yet it seems by no means improbable that
they are sense-organs. However problematical the function of this part of the organ
may be, there can be no doubt that