FAM. 10. KNERIIDAE.—Margin of the upper jaw formed by the praemaxillaries;

mouth toothless, not protractile. Parietals separated by the

supraoccipital. Pharyngeal bones toothless. Praecaudal vertebrae with

parapophyses. Body covered with small scales. Ventrals with 9 rays. No

adipose dorsal fin. Air-bladder present.

{616}The genus _Kneria_ comprises two species from the fresh waters of

tropical Africa, one from Angola, the other from East Africa.[693] Small

Loach-like Fishes, two to four inches long, with the upper jaw projecting

beyond the mouth, which is inferior and transverse; no barbels;

gill-membranes entirely grown to the isthmus, the gill-opening being a

rather narrow vertical slit; dorsal and anal fins short, the former

opposite, or nearly opposite, to the ventrals; the snout of the male(?) of

_K. angolensis_ is described as beset with small spine-like excrescences;

the intestinal tract makes several convolutions.

FAM. 11. CYPRINODONTIDAE.—Mouth protractile, the maxillaries excluded from

the oral border; teeth in the jaws and on the pharyngeal bones;

pterygo-palatine arch weak or rudimentary; opercular bones all well

developed. Basis cranii simple. Praecaudal vertebrae with strong

parapophyses, bearing the ribs; epipleurals inserted on the ribs.

Post-temporal forked. Ventrals, if present, with 5 to 7 rays. No adipose

dorsal fin. Air-bladder sometimes absent.

From a physiological point of view, this Family may be divided into

carnivorous forms, with short digestive tract, and phytophagous or

limnophagous ones, in which the intestine forms numerous coils. To the

first division belong the living genera _Cyprinodon_, _Characodon_,

_Tellia_, _Haplochilus_, _Fundulus_, _Rivulus_, _Cynolebias_, _Orestias_,

_Empetrichthys_, _Jenynsia_, _Pseudoxiphophorus_, _Belonesox_, _Gambusia_,

_Anableps_, among existing forms, and the fossil genera _Prolebias_

(Oligocene and Miocene) and _Pachylebias_ (Miocene); to the second, the

living genera _Poecilia_, _Mollienesia_, _Platypoecilus_, and _Girardinus_.

_Procatopus_, a near ally of _Haplochilus_, recently discovered in South

Cameroon, is remarkable for having the ventral fins inserted far forward,

below the pectoral fins.

These are small or very small Fishes,[694] only a few reaching a length of

about a foot, confined to fresh or brackish waters, recognisable externally

by the flat head with protractile mouth, the usually large scales, and the

absence of a well-developed lateral {617}line. The teeth vary much in

shape: cardiform, villiform, or compressed, and bi- or tri-cuspid; the

palate is either toothless, or teeth are present on the vomer. About 200

species are known, mostly from the American continent, only about 30 being

known from other parts of the world, viz. Southern Europe, Southern Asia

and Japan, and Africa. In many species the sexes are dissimilar, the female

being larger and less brilliantly coloured, with smaller fins; the anal fin

of the male may be modified into an intromittent organ by means of which

internal fertilisation takes place, the ova developing in a sort of uterus,

which the young leave in a more or less advanced stage of growth. The most

curious of the Cyprinodontids is the genus _Anableps_, of Central and South

America, surface-swimming Fishes, the strongly projecting eyes of which are

divided by a horizontal band of the conjunctiva into an upper part adapted

for vision in the air, and a lower for vision in the water, and the pupil

is divided into two parts by a constriction; the larger species grows to

the length of a foot.

[Illustration: FIG. 374.—_Anableps tetrophthalmus_, male, ½ nat. size.]

[Illustration: FIG. 375.—Distribution of the Cyprinodontidae.]

{618}FAM. 12. AMBLYOPSIDAE.—Mouth scarcely protractile, the maxillaries

excluded from the oral border; teeth small, in jaws and palate, and on the

pharyngeal bones. Praecaudal vertebrae with very strong parapophyses,

bearing the ribs on their upper surface; epipleurals inserted on the ribs.

Ventral fins rudimentary or absent. Vent jugular, close to the gill-clefts.

Air-bladder present.

[Illustration: FIG. 376.—A, _Chologaster cornutus_, and B, _Amblyopsis

spelaea_, nat. size. (After Jordan.)]

Small ovoviviparous Fishes, closely related to, and evidently derived from,

the Cyprinodontids, measuring from 1 to 5 inches, inhabiting ditches and

small streams, or confined to subterranean waters of limestone caves, in

the United States east of the Rocky Mountains. Six species, referable to

three genera, are known. In _Chologaster_, the eyes are well developed and

the body is coloured. _C. cornutus_ inhabits the lowland streams and swamps

of the South Atlantic States, from Virginia to Florida; _C. agassizii_ is

found in the underground streams of Kentucky and Tennessee; and _C.

papilliferus_ occurs under stones in the springs of south-western Illinois.

_Amblyopsis_ and _Typhlichthys_, which are evidently derived from the

former, or from forms closely related to it, have the eyes rudimentary and

more or less concealed under the skin, and the body is colourless.

_Amblyopsis spelaea_ is widely distributed in the caves east of the

Mississippi, {619}both north and south of the Ohio River; it is common in

the River Styx of the Mammoth Cave. _Typhlichthys subterraneus_ is found

with the latter species in the caves east of the Mississippi, but is

confined to the south side of the Ohio River, whilst _T_. (_Troglichthys_)

_rosae_ is found in the caves west of the Mississippi River. Of _Amblyopsis

spelaea_, the late Professor Cope has observed: "If these Amblyopses be not

alarmed, they come to the surface to feed, and swim in full sight, like

white aquatic ghosts. They are then easily taken by the hand or net, if

perfect silence is preserved, for they are unconscious of the presence of

an enemy except through the medium of hearing; this sense, however, is

evidently very acute, for at any noise they turn suddenly downwards, and

hide beneath stones, etc., on the bottom." Dr. Garman thinks, on the

contrary, that such a sense can hardly be developed in recesses where we

are accustomed to think any sounds other than those made by the rippling or

dripping water are almost unknown, and that it is through the sense of

touch, and not through hearing, that the Fish is disturbed. In fact, the

head is provided with a great number of tactile papillae, arranged in

transverse ridges, provided with nervous filaments, which evidently

compensate the loss of the visual organ.[695]

FAM. 13. STEPHANOBERYCIDAE.—This Family has hitherto been placed near the

Berycidae, among the Acanthopterygii, but there are no spinous rays in the

dorsal and anal fins; and the ventrals, formed of one simple and four or

five branched rays, are abdominal. The genus _Stephanoberyx_, with two

species from the Atlantic, at depths of 535 to 2949 fathoms, is

characterised by a large, thick, cavernous head, with thin bony

spine-bearing ridges, a large mouth bordered by the protractile

praemaxillaries, behind which are the large maxillaries, a short dorsal and

a short anal, opposed to each other behind the ventrals, and the body

covered with feebly imbricated scales, each bearing in the centre one or

several erect spines. The largest specimen measures 6 inches.

_Malacosarcus_, a small Fish from the Pacific, at depths of 2350 and 2425

fathoms, is very closely allied to _Stephanoberyx_, but its scales are very

thin and cycloid. The striking resemblance which the head {620}bears to

that of the Berycid _Melamphaes_ may be merely a case of convergence, and

it must be borne in mind that this appearance is approached by some species

of _Scopelus_, with which both _Malacosarcus_ and _Melamphaes_ were

originally confounded. The praecaudal vertebrae are provided with

parapophyses. I have ascertained on a specimen of _Stephanoberyx monae_

that the air-bladder is connected with the dorsal side of the stomach by a

short and comparatively wide duct.

[Illustration: FIG. 377.—_Stephanoberyx gillii_, nat. size. (After Goode

and Bean.)]

FAM. 14. PERCOPSIDAE.—Margin of the upper jaw formed by the

praemaxillaries; mouth small, not protractile, toothed; palate toothless.

Supraoccipital in contact with the frontals, separating the small

parietals. Basis cranii simple. Most of the praecaudal vertebrae with

parapophyses, on the upper surface of which the ribs are inserted; no

epipleurals. Post-temporal forked; post-clavicle present; scapular foramen

in the scapula, on which three hour-glass-shaped pterygials are inserted, a

fourth being inserted on the coracoid. Dorsal fin with two true spines;

anal with one or two; ventrals far forward, with 9 rays; pectorals inserted

rather high. A small adipose dorsal fin. Body covered with strongly ctenoid

scales. Air-bladder present (with open duct).

This is a most interesting group of Fishes, from the resemblance which they

bear to the Perches, and they have therefore been raised to the rank of a

sub-order, Salmopercae, by Jordan and Evermann, who regard them as "archaic

fishes, relics of some earlier fauna, and apparently derived directly from

the extinct transitional forms through which the Haplomi and Acanthopteri

have descended from allies of the Isospondyli [Malacopterygii]." On the

other hand, an analysis of their characters shows them to belong to the

Haplomi, of which they {621}may be regarded as highly specialised members,

having evolved in the direction of the Acanthopterygii.

Only two genera are known, each with a single species: _Percopsis_, from

the rivers and streams of Canada and the north-eastern United States, and

_Columbia_, more recently discovered in the sandy or weedy lagoons along

the Columbia River. These Fishes are of small size, not exceeding 6 inches

in length. Their eggs are unusually large.

[Illustration: FIG. 378.—_Columbia transmontana_, natural size. (After

Eigenmann.)]

SUB-ORDER 6. HETEROMI.

Air-bladder without open duct. Opercle well developed; parietal bones

separating the frontals from the supraoccipital. Pectoral arch suspended

from the supraoccipital or the epiotic, the post-temporal small and simple

or replaced by a ligament; no mesocoracoid. Ventral fins abdominal, if

present.

The Halosauridae and Notacanthidae are deep-sea Fishes of obscure

affinities. In the abdominal position of the many-rayed ventral fins and in

the absence of the mesocoracoid arch they agree with the Haplomi; but if,

as the investigations of Günther lead us to believe,[696] there is really

no open communication between the air-bladder and the digestive tract, they

{622}should be removed from this physostomous sub-order. The two families

have many characters in common, such as the attachment and structure of the

pectoral arch, which is devoid of a post-clavicle, the position of the

pectoral fins high up the sides, the strong parapophyses inserted very low

down on the centra of the vertebrae, the extent of the parietal bones,

which meet in a sagittal suture and separate the frontals from the

supraoccipital. The recent discovery of a third family, the Lipogenyidae,

which, in the structure of the dorsal fin, is exactly intermediate between

the two others, has lessened the gap between the Lyomeri (Halosauridae) and

Heteromi (Notacanthidae) of Gill, which I have proposed to unite in a

suborder under the latter name.

These Fishes are no doubt derived from forms in which a separate caudal fin

existed; such a type must have been near the Dercetidae, as defined by A.

S. Woodward, which may provisionally be placed here.

An imperfectly known Fish from the Chalk of Mount Lebanon, _Pronotacanthus

sahelalmae_, appears to bear some affinity to _Notacanthus_, and has been

placed in the same family; but its characters are not sufficiently defined

to refer it without doubt to this division.

There is a fifth family which may enter this sub-order: the Fierasferidae,

the structure of which has been exquisitely described and figured by

Emery.[697] Hitherto placed with or near the Ophidiidae, they differ widely

from them, as well as from all Acanthopterygians, in the conformation of

the skull, the supraoccipital being separated from the frontals by the

parietals, which form a long median suture. This is a feature which has

only been observed in Fishes with abdominal ventral fins, and although the

total absence of those fins in _Fierasfer_ deprive us of an important

criterion in deciding on its affinities, I am inclined to regard this

family as derived from an "abdominal" type. The conformation of the

pectoral arch has much in common with that of the Halosaurs, and,

notwithstanding the interpretation that has been given to the bones at the

back of {623}the cranium in the latter type, the same may be said, in a

general way, of the skull.

As pointed out by Emery, the very anterior position of the vent in the

Fierasferidae is directly related to the curious mode of life of these

Fishes, and the analogous condition obtained in various families, such as

the Gymnotidae, Nemichthyidae, Amblyopsidae, shows it to be a character of

relatively small systematic importance.

SYNOPSIS OF THE FAMILIES.

A. Vent posterior.

_a_. A distinct caudal fin; ordinary scales small or wanting, but

enlarged scutes along the side 1. _Dercetidae_.†

_b_. Tail tapering to a point; scales cycloid.

No spines; dorsal fin short, anal very long 2. _Halosauridae_.

Fins with spines, dorsal short, anal long 3. _Lipogenyidae_.

Dorsal fin formed of a series of spines, anal long, formed partly

of spines and partly of soft rays 4. _Notacanthidae_.

B. Vent immediately behind the gill-opening; no caudal fin; scales

absent 5. _Fierasferidae_.

FAM. 1. DERCETIDAE.—Body much elongate; ordinary scales small or wanting,

but two or more continuous series of enlarged scutes along each side; mouth

large, praemaxillaries apparently forming the greater part of the upper

border of the mouth, which is toothed; opercular apparatus complete. Dorsal

fin more or less extended, without spines; anal short, caudal separate;

ventrals with not less than 7 or 8 rays.

_Dercetis_, _Leptotrachelus_, _Leptecodon_, _Pelargorhynchus_, and

_Stratodus_, from the Upper Cretaceous of Europe, Syria, and North America.

FAM. 2. HALOSAURIDAE.—Body elongate, covered with cycloid scales, the tail

tapering to a point, without caudal fin; head with scales; mouth moderate,

bordered by the praemaxillaries and the maxillaries, both toothed;

suborbitals large; praeopercle rudimentary. Dorsal fin short, formed of

soft rays, above or a little behind the ventrals, which are rather far

back, and formed of 9 or 10 rays; anal very long, without spines, extending

to the end of the tail. Ovaries transversely laminated, the ova falling

into the abdominal cavity. Some 10 living species are known, referred to

three genera, inhabiting the Atlantic, Pacific, and Indian Oceans, at

depths of 500 to 1400 fathoms.

{624}In _Halosaurus_ the scales of the lateral line, which runs near the

lower profile, are scarcely enlarged, and are destitute of luminous organs.

_Halosaurichthys_ differs in the union of the ventral fins with each other,

as in _Notacanthus_. In _Halosauropsis_ the scales of the lateral line are

strongly enlarged and pouch-like, and bear photophores.

This family is one of great antiquity, being represented in the Upper

Cretaceous of Westphalia by _Echidnocephalus_, which, as shown by A. S.

Woodward, appears to have been closely related to _Halosaurus_.

[Illustration: FIG. 379.—_Halosauropsis macrochir_, ⅓ nat. size. (After

Günther.)]

FAM. 3. LIPOGENYIDAE.—Similar to the preceding in shape and in the position

of the dorsal fin, but with a toothless, roundish, inferior, suctorial

mouth, and with the short dorsal and the long anal formed partly of spines

and partly of soft rays. Head and body covered with minute scales; lateral

line nearer the dorsal than the ventral profile. Ventrals with 3 spines and

7 soft rays. A single species, _Lipogenys gillii_, from the North Atlantic,

865 fathoms.

[Illustration: FIG. 380.—_Lipogenys gillii_. (After Goode and Bean.)]

FAM. 4. NOTACANTHIDAE.—Body elongate, covered with very small cycloid

scales, the tail tapering to a point, without caudal fin; head scaly; mouth

small, inferior, bordered by the praemaxillaries only; jaws toothed; no

suborbitals; praeoperculum small; post-temporal replaced by ligament.

Dorsal fin formed of a series of short disconnected spines; anal very long,

formed partly of spines and partly of soft rays, extending to the end of

the tail. Ventrals with 1 to 5 spines and 7 to 10 soft rays.

{625}Two genera: _Notacanthus_, with the ventrals connate or confluent and

with 6 to 12 dorsal spines; and _Polyacanthonotus_, with the ventrals

separated and 27 to 38 dorsal spines. Nine species, from the Mediterranean,

the Atlantic, and the Pacific, at depths of 400 to 1875 fathoms.

[Illustration: FIG. 381.—_Notacanthus bonapartii_, ½ nat. size. (After

Vaillant.)]

FAM. 5. FIERASFERIDAE.—Body elongate or extremely attenuate, naked, the

tail tapering to a point or truncate, without distinct caudal fin; mouth

small, inferior, bordered by the praemaxillaries; jaws toothed; no

suborbitals; praeoperculum well developed. Dorsal and anal fins very long,

extending to the end of the tail, and formed entirely of soft rays. Ventral

fins absent. Vent situated immediately behind the gill-opening. Air-bladder

with a muscular apparatus for dilatation of its anterior part.

A single genus, _Fierasfer_, with about 10 species, distributed over nearly

all the warm and tropical seas, rarely found as far north as the west coast

of Ireland. _Encheliophis_, without pectoral fins, is the larval form of

_Fierasfer_.

_Fierasfer_ spends the greater part of its existence in the interior of

Holothurians and other Echinoderms as well as in bivalve Mollusca. It has

been observed to enter Holothurians by the posterior or anal aperture,

either head first or tail foremost, in the latter case availing itself of

the suction which takes place alternately with the expulsion of water by

that orifice; it remains near the anus, from which it projects its head in

search of food outside its host. It is neither a true parasite nor a

commensal or mutualist, in the sense given to these terms by Van Beneden,

but simply a lodger, "inquilino," as Emery puts it. Semper, however,

regards _Encheliophis vermicularis_ as a true parasite, feeding on the

viscera of the Holothurian in which it lives. Putnam has examined eight

specimens of a _Fierasfer_ from the Bay of Panama, which were obtained

alive from pearl oysters, and also one beautifully {626}enclosed in a

pearly covering deposited upon it by the oyster; a similar specimen is

preserved in the British Museum.

[Illustration: FIG. 382.—_Fierasfer acus_, penetrating into Holothurians, ⅖

nat. size. (After Emery.)]

SUB-ORDER 7. CATOSTEOMI.

Air-bladder, if present, without open duct. Parietal bones, if present,

separated by the supraoccipital. Pectoral arch suspended from the skull; no

mesocoracoid arch; coracoid usually very large. Ventral fins, if present,

abdominal, or pelvis attached to the coracoid bones.

The mouth is small and bordered by the praemaxillaries or by the

praemaxillaries and a small portion of the maxillaries. The air-bladder is

present, except in the Solenostomidae and Pegasidae.

Following the suggestions of Kner and Steindachner and Cope to their

logical conclusion, A. S. Woodward, in his valuable catalogue of the Fossil

Fishes in the British Museum, has united the Lophobranchs of Cuvier with

the Hemibranchs of Cope, a course which seems fully justified, and has

received {627}further support from the recent investigations of

Swinnerton,[698] who has proposed to unite the two groups under the new

name of Thoracostei. The name Phthinobranchii has also been suggested by O.

P. Hay for the same association. The structure of the Lophobranchs

(Solenostomidae and Syngnathidae) shows that these fishes are only

extremely specialised forms of the group of which the Sticklebacks are the

well-known type, and the character of the "tufted" gills alone is surely

not of sufficiently great importance to warrant the retention of the

Lophobranchii as a division equivalent to the sub-orders adopted in the

present classification. Besides, as recently pointed out by A. Huot,[699]

there is no fundamental difference, but only one of degree, between the

so-called tufted gill and the normal type; each "tuft" corresponds to one

branchial lamella, and at a certain stage of development the disposition of

the branchial lamella is the same in a _Syngnathus_ and in an ordinary

Teleostean. I have recently attempted to show[700] that the Lamprididae are

related to the Hemibranchii, although sufficiently distinct to warrant the

establishment of a division, named Selenichthyes.[701]

SYNOPSIS OF THE FAMILIES.

I. Praeoperculum and symplectic distinct; branchial apparatus fully

developed; gills pectinated; mouth terminal, toothless; post-temporal

forked, free; pelvic bones connected with scapular arch; ventral fins

with 15 to 17 rays; ribs long, sessile; fins without spines

(SELENICHTHYES) 1. _Lamprididae_.

II. Praeoperculum and symplectic distinct, latter much elongate;

branchial apparatus more or less reduced; gills pectinate;

post-temporal simple, immovable; mouth terminal (HEMIBRANCHII).

A. Mouth toothed.

1. Pelvic bones usually connected with scapular arch; spinous dorsal

represented by isolated spines.

Snout conical or but slightly tubiform; ventral fins with

1 spine and 1 or 2 soft rays; ribs slender, free; anterior

vertebrae not enlarged 2. _Gastrosteidae_.

Snout tubiform; ventral fins with 1 spine and 4 soft rays; {628}

ribs flattened, fused with the lateral bony shields;

anterior vertebrae not enlarged 3. _Aulorhynchidae_.

Snout tubiform; ribs slender, free; first vertebra enlarged

4. _Protosyngnathidae_.

2. Pelvic bones not connected with scapular arch; ventrals without

spine, with 5 or 6 rays; snout tubiform; first vertebra very

elongate, formed by the fusion of several.

Isolated dorsal spines; body scaly 5. _Aulostomatidae_.

No dorsal spines; body naked 6. _Fistulariidae_.

B. Mouth toothless; snout tubiform; two short dorsal fins, the first

with a few spines; ventral fins with 3 to 5 rays; anterior

vertebrae elongate.

Body covered with bony shields and small rough scales

7. _Centriscidae_.

Body completely cuirassed by bony shields which are fused with the

endoskeleton 8. _Amphisilidae_.

III. Praeoperculum absent; symplectic much elongate; branchial

apparatus more or less reduced; gill-lamellae reduced in number and

enlarged, forming rounded lobes; post-temporal simple, immovably

attached to the skull; mouth toothless, at the end of a tubiform

snout; body covered with bony plates (LOPHOBRANCHII).

Two dorsal fins; ventral fins present, with 7 rays; gill-openings

wide; exoskeleton of large star-like plates 9. _Solenostomidae_.

A single dorsal fin; no ventral fins; gill-openings very small;

exoskeleton in the form of rings 10. _Syngnathidae_.

IV. Praeoperculum and symplectic absent; gills pectinated; mouth

inferior, toothless; body entirely covered with bony plates; ventral

fin with 2 or 3 rays (HYPOSTOMIDES) 11. _Pegasidae_.

FAM. 1. LAMPRIDIDAE.—Body short and deep, with minute scales. Snout short;

mouth toothless, bordered by the praemaxillaries and, to a small extent, by

the maxillaries; opercular bones well developed. Gills four, pectinated;

branchial apparatus fully developed. Post-temporal bone forked. Vertebrae

very numerous (21 + 25), without transverse processes; ribs strong, long.

Fins without spines; dorsal and anal elongate. Pectoral fins with very

short pterygials folding downwards against the body. Pelvic bones connected

with the coracoids, which are very large, and do not form a suture at their

ventral extremity. Ventral fins with 15 to 17 rays.

The Opah or King-Fish (_Lampris luna_), the sole representative of this

family, is remarkable for its large size (growing to a length of four feet)

and its vivid colours. Its flesh is rich, and intermediate between that of

the Salmon and that of the Tunny. It is a pelagic fish of wide

distribution, known from the North {629}Atlantic and Mediterranean and from

distant points in the Pacific; specimens are occasionally captured on our

coasts. It feeds on other fish, but little is known of its habits and

nothing of its development.

The affinities of the _Lamprididae_ are very doubtful. _Lampris_ has

usually been placed with the Acanthopterygians, a view which is still

upheld by Gill.[702] I now agree with this high authority in regarding the

bone which I took for an infraclavicle as a much developed coracoid, and

the bone termed by me the coracoid as a pterygial. But it has also been

shown, by Starks, that such a thing as an infraclavicle does not exist in

the Stickleback, the bone so-called being only a part of the coracoid; and

as in most of the Sticklebacks the pelvic bones join the latter, the

resemblance between them and _Lampris_ remains. As I have previously

pointed out, the absence of spines in the fins, and the position of the

ventral fins, together with the great number of rays in the latter, which

is only met with in the lower Teleosteans, are characters which necessitate

the removal of _Lampris_ from the Acanthopterygians, and I cannot find a

better place for them than near the Gastrosteidae.

The whole question of the arrangement of the Physoclists with abdominal

ventrals (Catosteomi and Percesoces) is, I feel, much in need of revision,

and it may be found advisable to break up this group into a greater number

of sub-orders, in which case the Selenichthyes would stand by themselves;

the Hemibranchii and Lophobranchii would be united under the former name,

as proposed by Woodward, or under that of Thoracostei (Swinnerton) or

Phthinobranchii (Hay). The position in the system of the Pegasidae is still

somewhat doubtful. This family is regarded by some authors as related to

the mail-cheeked Acanthopterygians.

FAM. 2. GASTROSTEIDAE.—Body more or less elongate, naked or protected by

bony shields, tapering to a slender caudal peduncle. Head moderate, with

short or elongate and tubiform snout; mouth small, terminal, toothed;

opercular bones well developed; suborbitals in contact with praeoperculum,

protecting the cheek. Gills four, pectinated. Praecaudal vertebrae with

strong transverse processes and slender, free ribs. Spinous dorsal

represented by isolated spines. Pectoral fins with short {630}pterygials.

Pelvic bones usually connected with scapular arch. Ventral fins with one

spine and one or two soft rays.

[Illustration: FIG. 383.—Pectoral arch (left side) of _Gastrosteus

aculeatus_. (After Parker.) _cl_, Clavicle; _cor_, coracoid; _pt_,

pterygials; _sc_, scapula; _scl_, supra-clavicle.]

[Illustration: FIG. 384.—_Gastrosteus aculeatus_. × 1. (After Goode.)]

Four genera: _Gastrosteus_, _Apeltes_, _Eucalia_, _Spinachia_.

The little Three-spined and Two-spined Sticklebacks (_Gastrosteus

aculeatus_ and _G. pungitius_), which include many varieties that have been

regarded as distinct species, are among the best known of our British

Fishes. They are remarkable for the perfect indifference with which they

can be transported from fresh into salt water, and _vice versa_, and for

the elaborate nests which the males build in fresh or brackish water, and

over which they watch with the greatest vigilance after the female has

deposited her relatively large eggs.[703] These nests are made of weeds and

twigs fastened together by threads secreted by the kidneys of the male. The

{631}larger fifteen-spined Stickleback (_Spinachia vulgaris_) is entirely

marine; its nests are to be found on our coasts in sheltered rock-pools,

and they are made chiefly of sea-weeds and Hydrozoa. Sticklebacks are

short-lived, and are believed to breed only once.

The Gastrosteidae are restricted to the northern hemisphere, being more

abundant in the higher latitudes, extending to Iceland, Greenland, and

Bering Straits; the southernmost points of their distribution are Algeria

in the Old World, and Lower California in the New.[704]

A very large number of species have been described, but probably only about

a dozen deserve to stand.

[Illustration: FIG. 385.—Distribution of the Gastrosteidae.]

FAM. 3. AULORHYNCHIDAE.—The genera _Aulorhynchus_ and _Auliscus_, each with

one species from the Northern Pacific, much resemble _Spinachia_ in outward

form and in the equal size of the anterior vertebrae, but the snout is

still more produced, tubiform, and the ventral fins are formed of one spine

and four soft rays. The difference which justifies their separation as a

distinct family resides in the disposition of the ribs, which are flattened

and ankylosed to the lateral bony shields.

FAM. 4. PROTOSYNGNATHIDAE.—This family appears to be intermediate between

the Gastrosteidae and the Aulostomatidae, agreeing with the former in

possessing slender, free ribs, with the latter in having the first

vertebrae elongate, though to a {632}less degree than in _Aulostoma_. Its

only representative is _Protosyngnathus sumatrensis_, from a Tertiary

freshwater formation in Sumatra, which has been referred, without adequate

grounds, to _Aulorhynchus_ or _Auliscops_.[705]

FAM. 5. AULOSTOMATIDAE.—Allied to the Aulorhynchidae, differing in the

ventral fins devoid of spines, formed of 5 or 6 rays, widely removed from

the pectoral arch, the very elongate, saddle-shaped anterior vertebra

formed by the fusion of several, the large supratemporals produced backward

over the anterior vertebra, the very elongate pterygials of the pectoral

fin, and the compressed body covered with small ctenoid scales. Ribs are

rudimentary or absent. No suborbitals. The snout is long, tubiform; the

small terminal mouth bears bands of minute teeth, and the lower jaw has a

small barbel at the symphysis. A single genus, _Aulostoma_, with two

species from the Atlantic coasts of tropical America, and two from the

Eocene and Miocene of Europe. _A. coloratum_ grows to a length of 26

inches.

FAM. 6. FISTULARIIDAE.—Body greatly elongate, naked. First vertebra much

elongate, formed by the fusion of several; strong transverse processes to

the ribs in front and behind, those of two vertebrae suturally united; ribs

rudimentary or absent. Supratemporal much produced posteriorly, extending

over the anterior vertebrae; suborbitals absent; snout forming a long tube,

which terminates in a narrow mouth with minute teeth. Spinous dorsal

entirely absent. Pterygials of pectoral fin very elongate. Ventral fins

very small, with 6 soft rays, inserted far behind the pectoral girdle.

The Flute-mouths, _Fistularia_, which Dr. Günther describes as "gigantic

marine Sticklebacks living near the shore, from which they are frequently

driven into the open sea," are represented by three species, from the

tropical and subtropical parts of the Atlantic and Indo-Pacific. The middle

rays of the forked caudal fin are produced into a long filament. The

largest species, _F. tabaccaria_, reaches a length of 6 feet. The same

genus is represented by two species in the Upper Eocene and Oligocene of

Europe, and _Urosphen_, from the Upper Eocene, is regarded as allied to it.

{633}FAM. 7. CENTRISCIDAE.—Body moderately elongate, partially enclosed in

a bony armour, which is distinct from the endoskeleton. Anterior vertebrae

elongate, with strong parapophyses ankylosed to the exoskeleton; no ribs.

Suborbitals absent; snout forming a long tube, with small, terminal,

toothless mouth. Two dorsal fins, the anterior with a very strong spine.

Pterygials of pectoral fin very small. Ventral fins small, with 4 or 5

rays, the pelvic bones in contact with the postclavicles.

_Centriscus_, with five species in the Atlantic and Pacific Oceans,

represents this family at the present day. _C. scolopax_ has occasionally

been found on the English coast. Isolated spines from the Pliocene of

Tuscany have been referred to the same genus. _Rhamphosus_, from the Eocene

of Monte Bolca, is believed to have been allied to _Centriscus_.

FAM. 8. AMPHISILIDAE.—Near the preceding, but body extremely compressed and

completely enclosed in a thin bony armour which is fused with the

endoskeleton; the caudal region, much abbreviated, is free and relegated to

the ventral surface, the body terminating in the two dorsals, of which the

first bears a strong spine. The ventral fins are far back, very small,

formed of 3 or 4 rays.

_Amphisile_ is represented by three or four recent species in the Indian

and Pacific Oceans, and two are known from Upper Eocene and Oligocene beds

in Europe. Dr. Arthur Willey has observed these fishes in the Southern

Pacific. _A. strigata_ "lives in small shoals of about half-a-dozen

individuals, and swims about with rapidity in a vertical position, cleaving

the water with its razor-shaped body."

FAM. 9. SOLENOSTOMIDAE.—Body moderately elongate, with large star-like

ossifications. Anterior vertebrae elongate, without transverse processes;

no ribs. Snout much produced, tubiform; mouth, small, terminal, toothless;

no praeoperculum; symplectic elongate; gill-opening wide; gill-lamellae

small rounded lobes. Two short dorsal fins, the rays of the anterior not

articulated, flexible spines. Pterygials of pectoral fin very small.

Ventral fins large, with 7 rays, behind the pectoral arch. No air-bladder.

The unique genus, _Solenostomus_, with three or four species from the

Indian and Pacific Oceans, may be regarded as in many respects intermediate

between the _Centriscidae_ and the _Syngnathidae_. In the female the inner

side of the ventral fins coalesces {634}with the integuments of the body,

forming a large pouch for the reception of the eggs.

_Solenorhynchus_, from the Upper Eocene of North Italy, probably belongs to

this family, but its form is much more elongate, and the exoskeleton is in

regular rings.

FAM. 10. SYNGNATHIDAE.—Body more or less elongate, protected by an

exoskeleton forming rings. Anterior vertebrae not elongate; parapophyses

strong, ankylosed to the exoskeleton; no ribs. Snout much produced,

tubiform; mouth small, terminal, toothless; no praeoperculum; symplectic

elongate; gill-cleft reduced to a very small opening near the upper

posterior angle of the gill-cover; gill-lamellae small rounded lobes. A

single dorsal fin. Pectoral fins, if present, with very small pterygials;

ventrals absent. Caudal fin often absent; tail sometimes prehensile.

[Illustration: FIG. 386.—_Syngnathus pelagicus_.]

This family embraces about 175 marine species, and is represented over the

greater part of the world. Principal genera: _Siphonostoma_, _Syngnathus_,

_Penetopteryx_, _Ichthyocampus_, _Nannocampus_, _Osphyolax_, _Urocampus_,

_Doryichthys_, _Coelonotus_, _Stigmatophorus_, _Nerophis_, _Protocampus_,

_Gastrotoceus_, _Solenognathus_, _Hippocampus_, _Acentronura_,

_Phyllopteryx_.

Remains are found in the Upper Eocene and Miocene beds of Europe, and have

been referred to _Siphonostoma_ and _Syngnathus_, and to the extinct genus

_Calamostoma_. It is probable that _Pseudosyngnathus_, from the Upper

Eocene of Monte Bolca, is the type of a distinct family.

The best known members of this family are the Needle-Fish or Pipe-Fish

(_Siphonostoma_ and _Syngnathus_) and Sea-Horse (_Hippocampus_) of our

coasts. The latter, like _Amphisile_, swims with the body in a vertical

position. In most species the male takes charge of the eggs, in a pouch

under the tail (_Siphonostoma_, {635}_Syngnathus_, _Penetopteryx_,

_Nannocampus_, _Stigmatophorus_, _Hippocampus_), in a groove under the tail

(_Phyllopteryx_), or in a groove on the abdomen (_Doryichthys_,

_Coelonotus_, _Nerophis_, _Gastrotoceus_).

[Illustration: FIG. 387.—_Hippocampus guttulatus_. Male, showing

brood-pouch (_mp_). _a_, Anus; _b.a_, branchial aperture.]

[Illustration: FIG. 388.—_Phyllopteryx eques_. ½ nat. size.]

An Australian species of _Syngnathus_ has been described by E. P. Ramsay

under the name of _S. intestinalis_, from its living inside Holothurians,

in the manner of _Fierasfer_, and G. Lunel has observed a _Doryichthys_ to

offer a similar instance of inquilinism.

One of the most remarkable types of Syngnathids is _Phyllopteryx_, from

Australia. The spines and knobs of the head and body are furnished with

dermal appendages, which closely imitate the fucus among which they live.

FAM. 11. PEGASIDAE.—Body short or moderately elongate, encased in an

exoskeleton forming rings. Anterior vertebrae not elongate; no ribs. Snout

produced beyond the mouth, which is small, inferior, and toothless; no

praeoperculum, no symplectic; gill-opening very small; gills pectinated. A

single dorsal fin. Pectoral fins large, horizontal; ventrals reduced to one

or two filamentous rays, behind the scapular arch. Air-bladder absent.

{636}Five or six species, referable to two genera, _Pegasus_ and

_Parapegasus_, make up this family. They are very small fishes, inhabiting

the coasts of China, Japan, Arabia, the Malay Archipelago, and Australia.

_Pegasus_ is remarkable among all fishes in having the five anterior rays

of the pectoral fin transformed into strong spines.

SUB-ORDER 8. PERCESOCES.

Air-bladder, if present, without open duct. Parietal bones separated by the

supraoccipitaL Pectoral arch suspended from the skull; no mesocoracoid

arch. Ventral fins, if present, abdominal, or at least with the pelvic

bones not solidly attached to the clavicular arch.

This group connects the Haplomi with the Acanthopterygii, the

Scombresocidae being somewhat related to the Cyprinodonts,[706] whilst the

Anabantidae show distinct affinity to the Osphromenidae in the following

sub-order. Other families, previously included among the Scombriform

Acanthopterygians, are placed here on the assumption that the loose

attachment of the pelvic bones to the clavicles is a primitive character,

and not the result of degeneration, such as occurs in some cases among true

Acanthopterygians. Although this sub-order is perhaps only an artificial

association, it must be borne in mind that, notwithstanding the very wide

divergence which exists between the first and last families, and however

dissimilar their members may appear to be at first sight, a gradual passage

may be traced connecting the most aberrant types.

SYNOPSIS OF THE FAMILIES.

I. Ventral fins, if present, inserted far behind the pectorals; no spines

to the fins.

Ribs attached to the extremity of much-developed parapophyses; lower

pharyngeal bones completely united; pectoral fins inserted very

high up 1. _Scombresocidae_.

Ribs mostly sessile; lower pharyngeal bones distinct; pectoral {637}

fins nearer the ventral than the dorsal line 2. _Ammodytidae_.

II. Ventral fins, if present, more or less approximated to the pectorals.

A. Two well-developed dorsal fins, the anterior small and formed,

at least in part, of spinous rays.

1. Ribs attached to strong parapophyses.

Pelvic bones free or connected with the clavicles by ligament;

pectoral fins inserted high up 3. _Atherinidae_.

Pelvic bones suspended from the postclavicles; pectoral fins

inserted very high up; teeth very feeble or absent

4. _Mugilidae_.

Pelvic bones suspended from the postclavicles; pectoral fins

low down, with detached lower rays 5. _Polynemidae_.

Pelvic bones connected with the clavicles by ligament; pectoral

fins nearer the ventral than the dorsal line; dentition

powerful, cardiform; scales minute or absent

6. _Chiasmodontidae_.

2. Anterior ribs sessile; pelvic bones not connected with the

scapular arch; pectoral fins nearer the ventral than the

dorsal line 7. _Sphyraenidae_.

B. Spinous dorsal, if present, connected with the soft.

1. Anterior vertebrae without parapophyses; scales on head, if

present, small.

Oesophagus with lateral sacs which are beset with papillae

internally; spinous dorsal long; scales rhomboidal, in

oblique transverse series; pelvic bones free

8. _Tetragonuridae_.

Oesophagus with lateral sacs which are beset with toothed

papillae internally; spinous dorsal, if distinct, shorter

than the soft dorsal; scales moderate or small, cycloid,

often deciduous 9. _Stromateidae_.

No sacs in the oesophagus; fins without spines; scales very

small or absent 10. _Icosteidae_.

2. All, or all but the anterior two vertebrae with parapophyses;

scales on head large; a superbranchial cavity.

No spines to the fins 11. _Ophiocephalidae_.

Strong spines to the dorsal, anal, and ventral fins

12. _Anabantidae_.

FAM. 1. SCOMBRESOCIDAE.—Maxillary entering the border of the upper jaw;

dentition moderately strong or feeble. Lower pharyngeal bones united.

Praecaudal vertebrae with strong parapophyses supporting the ribs. Body

covered with cycloid scales. Pectoral fins inserted very high up; ventral

fins widely separated from the pectorals, without spines, with 6 rays.

Dorsal fin opposed to the anal, and likewise formed entirely of soft rays.

Air-bladder generally present, sometimes cellular.

The shape of the head and body vary greatly, and the pectoral fin may reach

an extraordinary wing-like development. The dorsal fin may be followed by a

series of finlets, as in many of the Scombridae. Most of the

Scombresocidae, of which about 200 species are known, are marine; some are

carnivorous, {638}others (_Hemirhamphus_) mainly herbivorous, feeding on

green algae. Nearly all are in the habit of making great leaps out of the

water, this tendency culminating in the Flying-Fish (_Exocoetus_), which

skip or sail through the air in a manner the explanation of which has given

rise to much controversy. According to the latest evidence[707] the sole

source of motive power is the action of the strong tail while in the water;

no force is acquired while the fish is in the air. The pectorals are not

used as wings but as parachutes. There is every passage between the small

pectoral fin of a Saurie (_Scombresox_) or a _Hemirhamphus_ and the

swallow-like wings of the most developed _Exocoetus_. The genus

_Hemiexocoetus_ is a very remarkable connecting form. The Gar-Pike

(_Belone_), of which one species is common on our coasts, have both jaws

produced into a long slender beak; the bones are green. In _Hemirhamphus_

the lower jaw only is prolonged; some of the species, living in fresh

water, are viviparous, the anal fin being modified into a copulatory organ,

as in many Cyprinodonts.

[Illustration: FIG. 389.—Gar-Pike (_Belone annulata_), × ⅓. (After Cuvier

and Valenciennes.)]

Scombresocidae occur in all the tropical and temperate seas. _Belone_,

_Scombresox_, and _Hemirhamphus_ are found in Upper Eocene and Miocene beds

of Europe, and, as stated above, _Protaulopsis_ should perhaps be referred

to this family.

{639}FAM. 2. AMMODYTIDAE.—Maxillary excluded from the border of the upper

jaw; mouth protractile; dentition feeble or absent. Lower pharyngeal bones

separate. Praecaudal vertebrae without parapophyses. Body covered with very

small cycloid scales. Pectoral fins nearer the ventral than the dorsal

line; ventral fins, if present, widely separated from the pectorals,

without spine, with 6 rays. Dorsal and anal fins more or less elongate,

formed of soft rays. Air-bladder absent.

The existing genera, _Ammodytes_, with 8 species, from the temperate coasts

of the northern hemisphere, and _Hypoptychus_, from northern Japan, with a

single species, are deprived of ventral fins, and their exact relations

remained obscure until the structure of the Oligocene _Cobitopsis_ revealed

their affinity to the _Scombresocidae_, or at least their pertinence to the

present suborder. The Greater Sand-Eel or Launce (_Ammodytes lanceolatus_)

and the Lesser Sand-Eel (_A. tobianus_) are common on our coasts, and are

remarkable for the manner in which, by means of their sharp-pointed snout,

they bury themselves with great rapidity in the sand, darting in and out

like arrows.

[Illustration: FIG. 390.—_Cobitopsis acuta_. (Restoration by A. S.

Woodward.)]

FAM. 3. ATHERINIDAE.—Maxillary excluded from the border of the upper jaw;

dentition more or less developed. Body covered with cycloid or ctenoid

scales. Ribs attached to strong parapophyses. Pectoral fins inserted high

up; ventral fins more or less approximated to the pectorals, with one spine

and five soft rays; pelvic bones connected with the clavicular symphysis by

a ligament. Two well-separated dorsal fins, the anterior small and formed,

at least in part, of spinous rays. Air-bladder present.

Carnivorous Fishes, mostly marine and of small size, much valued as food,

and distributed along the coasts of most tropical and temperate seas; some

inhabit fresh waters. A silvery lateral band, or "stole," is usually

present. About 65 species are known, referred to 14 genera: _Atherina_,

_Iso_, _Chirostoma_, _Thyrina_, _Atherinella_, _Labidesthes_,

_Atherinopsis_, _Atherinops_, _Telmatherina_, _Neatherina_, _Pseudomugil_,

_Rhombatractus_, _Aida_, _Melanotaenia_.

{640}Represented in the Upper Eocene of Europe by several species of

_Atherina_ and by the extinct genus _Rhamphognathus_.

FAM. 4. MUGILIDAE.—Maxillary excluded from the border of the upper jaw;

dentition feeble or absent. Body covered with cycloid scales. Ribs attached

to the extremity of strong parapophyses. Pectoral fins inserted high up;

ventral fins more or less approximated to the pectorals, with one spine and

five soft rays; pelvic bones suspended from the post-clavicles. Two

well-separated dorsal fins, the anterior formed of a small number of

spines. Air-bladder present.

These Fishes are closely related to the preceding, of which they are a

further specialisation, the pharyngeal bones having a complicated

structure, much reducing the oesophageal opening, and the vertebrae being

reduced in number (24 to 26 instead of 32 to 60). They feed on organic

matter contained in mud, and inhabit the fresh waters and coasts of the

temperate and tropical regions. The species number about 100. Principal

genera: _Mugil_, _Myxus_, _Anostomus_, _Joturus_. Grey Mullets (_Mugil_)

are represented on our coasts by three species, valued as food, one of

which (_M. capito_) has a remarkably wide range, occurring from Scandinavia

to the Cape of Good Hope. Remains referred to the same genus occur in the

Miocene and Oligocene.

[Illustration: FIG. 391.—Shoulder-girdle and pelvis of _Polynemus

quadrifilis_. _cl_, Clavicle; _cor_, coracoid; _pec_, pectoral rays; _pel_,

pelvis; _pt_, pterygials; _ptcl_, post-clavicle; _pte_, post-temporal;

_sc_, scapula; _scl_, supra-clavicle; _ven_, ventral rays.]

FAM. 5. POLYNEMIDAE.—Maxillary excluded from the border of the upper jaw;

dentition feeble. Body covered with ctenoid {641}scales. Ribs attached to

the extremity of strong parapophyses. Pectoral fin inserted low down, with

a lower portion consisting of free rays; the upper portion, or fin proper,

attached to the scapula, the lower to a fenestrate bone which appears to be

formed by coalesced pterygials (Fig. 391, _pt_.). Ventral fin more or less

approximated to the pectoral, with one spine and five soft rays; pelvic

bones suspended from the post-clavicles. Two well-separated dorsal fins,

the anterior formed of a small number of spines. Air-bladder, if present,

very large.

The vertebrae number 24 (10 + 14).

[Illustration: FIG. 392.—_Polynemus quadrifilis_, × ¼. (After Cuvier and

Valenciennes.)]

Three closely allied genera: _Polynemus_, _Pentanemus_, and _Galeoides_,

with about 25 species, from the shores of tropical seas, often entering

rivers. Some attain a length of 4 feet, and are valued as food or for the

isinglass yielded by their air-bladder. The free pectoral filaments are

organs of touch, and can be moved independently of the fins.

FAM. 6. CHIASMODONTIDAE.—The deep-sea genera, _Chiasmodon_,

_Pseudoscopelus_, and _Champsodon_, which have been placed either with the

Gadidae, the Trachinidae, or the Berycidae, may be referred to the

Percesoces, as the pelvic fins have only a ligamentous connexion with the

pectoral arch. Unfortunately, the skeleton has only been examined in

_Champsodon_; it is remarkably similar to that of the Atherinidae. As in

_Atherinichthys_, the posterior extremity of the air-bladder is protected

by a bony sheath formed by the expanded ring-like haemal processes of the

anterior caudal vertebrae. Vertebrae 32 (16 + 16). The {642}scales are

absent or very small and spinulose, the mouth large, with cardiform teeth;

spinous dorsal short, soft dorsal and anal elongate. _Chiasmodon_ and

_Pseudoscopelus_ have a complicated system of sensory organs on the body,

which in the latter suggest the photophores of Scopelids. _Champsodon

vorax_ is a fish of extreme voracity, swallowing prey much larger than

itself. Only four species of this family are known.

FAM. 7. SPHYRAENIDAE.—Maxillary excluded from the border of the upper jaw;

dentition very strong. Body covered with cycloid scales. Anterior ribs

sessile, the rest inserted on parapophyses. Pectoral fin nearer the ventral

than the dorsal outline; ventral fin more or less approximated to the

pectoral, with 1 spine and 5 soft rays; pelvis not connected with the

pectoral arch. Two well-separated dorsal fins, the anterior formed of a

small number of spines. Air-bladder large. Vertebrae 24.

Carnivorous Pike-like Marine Fishes from the tropical and sub-tropical

seas, often found at the mouths of rivers. The "Barracudas" form a single

genus, _Sphyraena_, with about 20 species, the largest of which grow to 8

feet and are dangerous to people bathing; many are valued as food, but some

are reported to be poisonous, at least at certain seasons. Remains of

several species are known from the Eocene and later periods in Europe and

North America.

FAM. 8. TETRAGONURIDAE.—Maxillary excluded from the border of the upper

jaw; dentition feeble. Oesophagus with lateral sacs which are beset with

papillae internally; a series of gill-raker-like knobs below the

pseudobranchiae. Body covered with rhomboidal, striated scales in oblique

transverse series, those of every single transverse series coherent. Ribs

mostly sessile. Pectoral fin nearer the ventral than the dorsal outline.

Ventral fin with 1 spine and 5 soft rays, near the pectoral, but pelvis

free from the pectoral arch. A long continuous dorsal fin, its anterior

portion formed of numerous short spines. Air-bladder absent. Vertebrae 58.

This family includes a single, rather rare fish, _Tetragonurus cuvieri_,

from the Mediterranean and neighbouring parts of the Atlantic and the South

Pacific. It is said to descend to great depths at certain seasons, and to

feed on Medusae; its flesh is poisonous. Young specimens have been observed

by Emery to live in the respiratory cavity of large Salpae.

{643}FAM. 9. STROMATEIDAE.—Although including a number of forms very unlike

_Tetragonurus_ in external appearance, there is no doubt that this family,

hitherto placed near the Scombridae, is very closely allied to the

preceding, agreeing with it in the presence of lateral oesophageal sacs

bearing internally papillae (which are besides beset with setiform teeth),

and, in most genera, in the presence of a series of knobs, more or less

similar to gill-rakers, below the pseudobranchiae. The pelvic bones are

sometimes free from the pectoral arch, as in the Tetragonuridae, sometimes

more closely attached, but only by ligament, and movable. The principal

difference resides in the scales, which are always cycloid and usually very

small and more or less deciduous, and in the spinous dorsal being shorter

than the soft, or even quite rudimentary. The ventrals are sometimes

absent. The air-bladder is present or absent. The number of vertebrae

varies from 24 to 46.

Marine Fishes, pelagic or deep-sea, feeding on Crustaceans, Medusae, or the

fry of other fish. About 45 species are known, referable to 10 genera:

_Nomeus_, _Cubiceps_, _Psenes_, _Seriolella_, _Psenopsis_, _Centrolophus_,

_Lirus_, _Stromateus_, _Peprilus_, and _Stromateoides_. Many of the species

have a wide distribution, but are rare in collections.[708] The Black-Fish

(_Centrolophus niger_) and its close ally _C. britannicus_, and the

Rudder-Fish (_Lirus perciformis_ and _L. medusophagus_), have occurred, at

rare intervals, on the British coasts. The Stromateidae were represented by

several species in the Cretaceous (_Platycormus_ and _Homosoma_).

The widely distributed _Nomeus gronovii_, so remarkable for its enormous

ventral fins, folding in a ventral groove, has been observed in New South

Wales to be only found on the coast when the Siphonophores called

"Portuguese Men-of-War" or _Physalia_ are driven ashore, the fish swimming

beneath them, as the young _Caranx_ are in the habit of doing under

Medusae. As observed by Waite,[709] the benefit of such a partnership must

primarily be with the fish, for it is a voluntary agent, whereas the

_Physalia_ has no power of locomotion. "If the fish secures safety from its

enemies by entering the area embraced by the deadly tentacles of the

_Physalia_, which attain a length of 10 to {644}12 feet, it must be immune

to their influence: a remarkable condition, considering that small fish

have often been seen in their stomachs and entangled in their tentacles."

This observer adds: "It is probable that, in addition to protection, the

fish derives its food from association with the _Physalia_, much as does

the Remora in accompanying a shark. The _Physalia_ doubtless paralyses many

more animals than it can consume—the residue falling to the lot of the

fishes, which may be present to the number of ten."

FAM. 10. ICOSTEIDAE.—The so-called "Rag-Fishes," in which the skeleton is

quite soft and cartilaginous, are aberrant deep-sea forms evidently related

to the Stromateidae; they lack the oesophageal teeth and the processes of

the last gill-arch, but _Icosteus_ at least has the gill-raker-like knobs

below the pseudobranchiae. The pelvis is widely separated from the

clavicles. Spines are absent in the fins, and the body is naked or covered

with small cycloid scales. Vertebrae in large number (up to 70).

_Icosteus_, _Icichthys_, and _Acrotus_, each with a single species, from

the Pacific coast of North America.

[Illustration: FIG. 393.—_Icosteus enigmaticus_, × ⅓. (After Goode and

Bean.)]

FAM. 11. OPHIOCEPHALIDAE.—Maxillary excluded from the border of the upper

jaw. Head and body covered with cycloid scales. Anterior ribs sessile, the

remainder inserted on the parapophyses. Pectoral fin low down; ventral fin,

if present, near the pectoral, with 6 soft rays; pelvic bones connected

with the clavicular symphysis by ligament. Dorsal and anal fins long,

without spines. Air-bladder present, much elongate.

These Fishes are provided with an accessory superbranchial cavity, and are

able to breathe atmospheric air. All are {645}inhabitants of fresh waters

and are carnivorous. Only two genera are known: _Ophiocephalus_, with about

25 species from Eastern Asia and 3 from Tropical Africa, and _Channa_,

distinguished by the absence of ventral fins, with 3 species from Ceylon

and China.

[Illustration: FIG. 394.—Distribution of the Ophiocephalidae.]

[Illustration: FIG. 395.—Distribution of the Anabantidae.]

FAM. 12. ANABANTIDAE.—Differ from the preceding, to which they are closely

related, in having part of the dorsal and anal fins and the outer ventral

ray spinous, and a shorter, Perch-like body covered with ctenoid scales.

The accessory superbranchial organ is still more developed, with thin bony

laminae, which are more or less folded and covered with a mucous membrane.

These Fishes can live a long time out of water, and the name _Anabas

scandens_, or Climbing Perch, recalls the fact that its first observers in

India ascribed to it the habit of climbing up low trees by means of the

spines with which its {646}gill-covers and ventral fins are armed. This

species, which attains a length of 8 inches, is found in estuaries and

fresh waters of India, Ceylon, Burma, and the Malay Peninsula and

Archipelago; 3 other species occur in the Malay Archipelago, and 11 in

Africa.

SUB-ORDER 9. ANACANTHINI.

Air-bladder without open duct. Parietal bones separated by the

supraoccipital; prootic and exoccipital separated by the enlarged

opisthotic. Pectoral arch suspended from the skull; no mesocoracoid arch.

Ventral fins below or in front of the pectorals, the pelvic bones posterior

to the clavicular symphysis and only loosely attached to it by ligament.

Fins without spines; caudal, if present, without expanded hypural,

perfectly symmetrical, and supported by the neural and haemal spines of the

posterior vertebrae and by basal bones similar to those supporting the

dorsal and anal rays. This type of caudal fin must be regarded, as I have

pointed out,[710] as secondary, the Gadidae being, no doubt, derived from

Fishes like the Macruridae, in which the homocercal fin had been lost. The

scapular foramen or fenestra is nearly always between the scapular and

coracoid bones, as in the Trachinidae and several allied families, not in

the coracoid, as in the other Acanthopterygians. The first two vertebrae

have no epipleurals.

Mr. C. Tate Regan,[711] who has recently given a good definition of the

Anacanthini, divides them into three families.

[Illustration: FIG. 396.—Skeleton of caudal fin of _Gadus virens_.]

{647}FAM. 1. MACRURIDAE.—Mouth more or less inferior, protractile; teeth

small, none on palate. Anterior vertebrae without transverse processes,

with the ribs sessile, the rest with strong transverse processes supporting

the ribs, which themselves bear epipleurals. Gill-membranes free from

isthmus or narrowly attached; 6 or 7 branchiostegal rays; gills 3½ or 4;

pseudobranchiae rudimentary or absent. Ventral fins below the pectorals,

with 7 to 12 rays. Body short, tail elongate and tapering to a point,

without caudal fin. A short anterior dorsal, with a single simple ray, and

a long dorsal and anal meeting together at the end of the tail, formed

entirely of articulated rays—the two dorsals sometimes continuous

(_Lyconus_).

Deep-sea Fishes with very large eyes and small or rather large mouth,

usually covered with rough spiny scales; a mental barbel is present, except

in _Lyconus_, and the muciferous cavities of the skull are strongly

developed, the bones being remarkably thin. About 120 species are known,

some of which have a wide distribution. Macrurids have been found in all

the seas where deep-sea dredging has been practised—the greatest depth at

which they have been obtained being 2650 fathoms. Principal genera:

_Macrurus_, _Gadomus_ (with perforate scapula) _Coryphaenoides_,

_Hymenocephalus_, _Malacocephalus_, _Lionurus_, _Trachyrhynchus_,

_Steindachneria_, _Bathygadus_, _Lyconus_, _Macruronus_. A larval form of

this family has received the name of _Krohnius_; it is remarkable for the

filamentous prolongation of the ventral rays, which recalls the larval

_Trachypterus_.

[Illustration: FIG. 397.—_Macrurus carminatus_, × ⅓. (After Goode.)]

FAM. 2. GADIDAE.—Mouth moderate or large, more or less protractile.

Anterior vertebrae without transverse processes, with the ribs sessile, the

rest with strong transverse processes, {648}usually supporting ribs,[712]

which themselves bear epipleurals. Gill-membranes free from isthmus or

narrowly attached; 6 to 8 branchiostegal rays; gills 4, a slit behind the

fourth; no pseudobranchiae. Ventral fins jugular, with 1 to 9 soft rays.

Body more or less elongate, covered with small cycloid scales. Dorsal and

anal fins elongate, formed of articulated rays, sometimes divided into two

or three distinct portions. Caudal fin more or less distinct, supported by

the unmodified or but slightly modified neural and haemal spines of the

last vertebrae, which are perfectly symmetrical (diphycercal or isocercal

type).

A mental barbel is often present, as in the Macruridae, and the suture

between the frontal bones has disappeared in most of the members of this

very natural family. About 120 species are distinguished, mostly marine,

many being adapted to life at great depths. All are carnivorous. They

inhabit chiefly the northern seas, but many abyssal forms occur between the

tropics and in the southern parts of the Atlantic and Pacific. Principal

genera: _Gadus_, _Merluccius_, _Holargyreus_, _Lotella_, _Physiculus_,

_Phycis_, _Haloporphyrus_, _Tripterophycis_, _Lota_, _Molva_, _Onus_,

_Bregmaceros_, _Antimora_, _Raniceps_, _Brosmius_.

[Illustration: FIG. 398.—Cod (_Gadus morrhua_), × ⅕. (After Goode.)]

Several species, referred to _Gadus_ and _Brosmius_, have been described

from the Miocene. _Nemopteryx_, which is allied to _Gadus_, is from the

Oligocene.

The fishes of this family are among the most important from an economic

point of view. It will suffice to allude merely by name to the following

among the European forms:—The Cod-Fish (_Gadus morrhua_), the largest

species, reaching a length of {649}4 feet and a weight of 100 lbs., the

Haddock (_G. aeglefinus_), the Whiting (_G. merlangus_), the Bib or Pout

(_G. luscus_), the Pollack (_G. pollachius_), the Coal-Fish (_G. virens_),

the Hake (_Merluccius vulgaris_), and the Ling (_Molva vulgaris_). Species

of _Merluccius_ occur also on the coasts of Chili and of New Zealand. The

Rocklings (_Onus_ or _Motella_) are of small size; several species are of

common occurrence in our tide-pools. The Burbot (_Lota vulgaris_) is a

freshwater fish, exceeding a length of 3 feet, of excellent quality, but

unfortunately local and rare in this country.

FAM. 3. MURAENOLEPIDIDAE.—Closely related to the Gadidae, from which they

differ in not having a separate caudal fin, in the gill-openings being

narrow and below the base of the pectorals, in the increased number (ten)

of the pectoral pterygials,[713] and in the peculiar scales, similar to

those of the Anguillidae. Ventrals with 5 rays. A mental barbel.

A single genus, _Muraenolepis_, from the coast of Kerguelen Island.

{650}CHAPTER XXIII

TELEOSTEI (_CONTINUED_): ACANTHOPTERYGII—OPISTHOMI—PEDICULATI—PLECTOGNATHI

SUB-ORDER 10. ACANTHOPTERYGII.

Air-bladder usually without open duct. Opercle well developed;

supraoccipital in contact with the frontals. Pectoral arch suspended from

the skull; no mesocoracoid. Ventral fins thoracic or jugular, more or less

firmly attached to the clavicular arch. Gill-opening usually large, in

front of the base of the pectoral fin.

The character from which this sub-order, the most comprehensive of the

whole class, derives its name, viz. the presence of non-articulated, more

or less pungent, rays in the dorsal and anal fins, is by no means

universal, exceptions to the rule being numerous. The mouth is usually

bordered by the premaxillaries to the exclusion of the maxillaries, and if

these should, by exception, enter the oral edge, they are always toothless.

The ventral fins are sometimes inserted at some distance behind the base of

the pectorals (_Haplodactylidae_, _Platycephalidae_), in which case,

however, this is due to the elongation of the pelvic bones, which are

solidly attached to the clavicular arch. The sub-order is broken up into

divisions, which follow in somewhat arbitrary order, the natural affinities

being opposed to a linear arrangement; the annexed diagram is intended to

remedy this defect.

SYNOPSIS OF THE DIVISIONS.

I. No suborbital stay, or process extending from the suborbital bones

towards the praeoperculum; basis cranii double in the symmetrical

forms. Primary shoulder-girdle composed of a perforate scapula {651}

and a coracoid; of the four or five pterygials, or basal bones

of the pectoral fins, only one or two are in contact with the

coracoid; ventral fins thoracic.

Rays of the caudal fin not strongly forked at the base; hypural

usually with a basal spine or knob-like process on each side;

epipleural bones usually inserted on the parapophyses or on the

ribs; dorsal fin usually with strong spines; caudal peduncle

rarely much constricted I. PERCIFORMES.

Rays of the caudal fin strongly forked at the base, embracing a

considerable portion of the hypural, which always bears a basal

spine; epipleural bones usually inserted on the centra or on the

parapophyses, rarely on the ribs; dorsal spines feeble or detached;

caudal peduncle much constricted; scales usually very small or

absent II. SCOMBRIFORMES.

[Illustration: FIG. 399.—Diagram showing probable relationship of the

various groups to one another.]

Rays of the caudal fin not strongly forked at the base; ventral {652}

fins with one spine and six to eight soft rays, _or_ cranium

asymmetrical III. ZEORHOMBI.

II. No suborbital stay; basis cranii double; scapula absent, the

pterygials inserted on the coracoid; ventral fins thoracic

IV. KURTIFORMES.

III. No suborbital stay; basis cranii simple; scapula and coracoid

more or less reduced, sometimes vestigial; pterygials large, only

one or two in contact with the coracoid; ventral fins thoracic

V. GOBIIFORMES.

IV. No suborbital stay; basis cranii simple; a perforate scapula;

three pterygials in contact with the coracoid; ventral fins

thoracic; a suctorial laminated disk on the upper surface of

the head VI. DISCOCEPHALI.

V. A suborbital stay, the second suborbital bone more or less produced

on the cheek or joining the praeoperculum; ventrals thoracic

VII. SCLEROPAREI.

VI. No suborbital stay; ventrals usually jugular or mental; if thoracic,

structure of the pectoral arch differing from that ascribed to the

first five divisions of this Synopsis.

Pectoral fin with vertical or subvertical base; anal fin usually

elongate, rarely small VIII. JUGULARES.

Pectoral fin with horizontal or sub-horizontal base; body exceedingly

compressed; dorsal fin with all the rays simple; anal fin absent

or very small IX. TAENIOSOMI.

DIVISION I.—PERCIFORMES.

No bony stay for the praeoperculum. Basis cranii double. Spinous dorsal

usually well developed. None of the epipleural bones attached to the centra

of the vertebrae in the praecaudal region. Pectoral arch with

well-developed scapula and coracoid, the former pierced by a foramen or

fenestra; pterygials longer than broad, more or less regularly

hour-glass-shaped, four or five in number, one or two of which are in

contact with the coracoid. Ventral fins thoracic.

This large group, consisting chiefly of marine forms, has members in all

parts of the world, with the exception of the Arctic and Antarctic regions,

and was already represented by numerous Berycidae and a few Serranidae and

Scorpididae in the Upper Cretaceous. The division into families is a task

of considerable difficulty, and the necessities of a linear arrangement

result in the breaking up of some natural sequences. Thus it appears highly

probable that the Scorpididae, themselves derived, together with the

Serranidae, from the Berycidae, lead to the Carangidae in the division

Scombriformes, whilst a nearly perfect passage can be traced between the

Acanthuridae of this division and the Balistidae among the Plectognaths.

{653}SYNOPSIS OF THE FAMILIES.

I. Gills four, a slit behind the fourth.

A. Two nostrils on each side.

1. Ventrals with 1 spine and 6 to 13 soft rays. 1. _Berycidae_.

2. Ventrals with not more than 5 soft rays.

a. Lower pharyngeal bones not completely united, showing at least

a median suture.

α. Gill-membranes nearly always free from isthmus.

* Ventrals little if at all behind the pectorals.

† Third vertebra without transverse processes _or_ with

sessile ribs.

§ A more or less developed subocular shelf, or inner lamina

of the suborbitals supporting the eye-ball, sometimes

reduced to a mere process of the second suborbital.

‖ Ribs inserted on the transverse processes, when these

are developed.

Body covered with very large bony scales; ventrals

with a very strong spine and 2 or 3 very short

soft rays 2. _Monocentridae_.

Dorsal very short, with few graduated, adnate spines,

anal very long 3. _Pempheridae_.

Spinous dorsal usually well developed, soft dorsal

usually not much more developed than the anal;

palate usually toothed 11. _Serranidae_.

Dorsal and anal fins elongate and formed mostly of

articulated soft rays, the spines feeble and few

12. _Pseudochromididae_.

Dorsal and anal fins much elongate, without distinct

spines; body band-like 13. _Cepolidae_.

Teeth in the jaws fused to form a beak

14. _Hoplognathidae_.

Soft dorsal and anal much elongate; a separate

spinous dorsal 15. _Sillaginidae_.

Soft dorsal much longer than the anal; a separate

spinous dorsal 16. _Sciaenidae_.

‖‖ Ribs mostly sessile, behind the parapophyses; body

deep; mouth moderately large and protractile.

Post-temporal forked, distinct from skull

25. _Scorpididae_.

Post-temporal completely ankylosed to the skull;

mouth very protractile 26. _Caproidae_.

§§ No subocular shelf.

‖ Ribs mostly sessile, behind the parapophyses;

anal spines 3 to 14.

Teeth conical; palate toothed; mouth feebly

protractile 4. _Centrarchidae_.

Teeth incisor-like; fins densely scaled

5. _Cyphosidae_.

Teeth conical; palate toothless 6. _Lobotidae_.

Maxillary very slender; mouth very protractile

7. _Toxotidae_.

No entopterygoid; mouth very protractile

8. _Nandidae_.

‖‖ Ribs inserted on the transverse processes when {654}

these are developed; not more than 3 anal spines.

Mouth not or but feebly protractile; spinous dorsal

usually longer than the soft; anal with 1 or 2

spines 9. _Percidae_.

Mouth moderately protractile; palate toothed; spinous

dorsal not longer than the soft; anal with 2 or 3

spines 10. _Acropomatidae_.

Mouth very protractile; palate toothless; praemaxillary

with an upwardly directed lateral process

17. _Gerridae_.

Mouth moderately protractile; palate toothed; anal

longer than soft dorsal; body scaly

18. _Lactariidae_.

Mouth moderately protractile; palate toothless; anal

much longer than soft dorsal; body naked

19. _Trichodontidae_.

†† Transverse processes developed on the third vertebra and

bearing the ribs; palate usually toothless.

No subocular shelf; teeth small 22. _Pristipomatidae_.

A subocular shelf; teeth often large, either cutting

in front or molar-like on the sides 23. _Sparidae_.

A subocular shelf; teeth very small or absent; a pair

of barbels on the throat 24. _Mullidae_.

** Ventrals rather far behind the base of the pectorals;

lower pectoral rays unbranched, often thickened; no

subocular shelf.

Anal fin nearly as long as the soft dorsal

20. _Latrididae_.

Anal fin much shorter than the soft dorsal

21. _Haplodactylidae_.

β. Gill-membranes attached to the isthmus.

* Scales well developed; vertebrae 24 or more.

A subocular shelf; mouth small; palate toothless

27. _Chaetodontidae_.

No subocular shelf; mouth small; palate toothless

28. _Drepanidae_.

Subocular shelf more or less developed; a superbranchial

respiratory organ 31. _Osphromenidae_.

** Scales minute; mouth small; vertebrae 22 or 23.

Post-temporal not distinctly forked; vertebrae with strong

transverse processes; ventrals with 1 spine and 2 to 5

soft rays 29. _Acanthuridae_.

Post-temporal forked; vertebrae without transverse

processes; ventrals with 2 spines and 3 soft rays

between them 30. _Teuthididae_.

b. Lower pharyngeals completely united into one bone, without

median suture 32. _Embiotocidae_.

B. A single nostril on each side; lower pharyngeal bones more or

less completely united, but with persistent suture; no subocular

shelf; palate toothless 33. _Cichlidae_.

II. Gills three and a half; lower pharyngeals completely united into

one bone, without median suture; palate toothless.

A single nostril on each side; teeth conical or incisor-like;

a subocular shelf 34. _Pomacentridae_.

Two nostrils on each side; anterior teeth usually strong and

canine-like; teeth on pharyngeal bones conical or tubercular;

no subocular shelf 35. _Labridae_.

Two nostrils on each side; anterior teeth more or less coalesced

into a beak; teeth on pharyngeal bones flat, tessellated; no

subocular shelf 36. _Scaridae_.

{655}FAM. 1. BERYCIDAE.—One or several of the suborbitals emitting an

internal lamina supporting the eye; entopterygoid present. Anterior

vertebrae without transverse processes; all or most of the ribs inserted on

the transverse processes where these are developed. Two nostrils on each

side. Gill-membranes free from isthmus; 4 to 10 branchiostegal rays; gills

4, a slit behind the fourth; pseudobranchiae. Lower pharyngeal bones

separate. Ventral fins with 1 spine and 6 to 13 soft rays.

[Illustration: FIG. 400.—_Beryx splendens_, ⅓ nat. size. (After Goode and

Bean.)]

This family is remarkable for the retention of two archaic characters: the

large number of rays to the ventral fins and the duct between the

air-bladder and the digestive tract; the latter character is, however, not

universal, and has only been found in two genera (_Beryx_ and

_Holocentrum_). The scaling of the body varies greatly, and so does the

development of the spines in the vertical fins. Several genera

(_Melamphaes_, _Anoplogaster_, _Trachichthys_, etc.) have the head studded

with large muciferous cavities which are covered with a thin skin. The vent

is usually situated far behind the ventral fin, but in _Paratrachichthys_,

a genus closely allied to _Trachichthys_, it occupies a more anterior

position, between the ventrals, whilst in _Aphredoderus_ it shifts still

further with age, opening on the throat in the adult.

The Berycidae were abundantly represented in Cretaceous deposits by _Beryx_

and other genera more or less closely related to living forms, and they

appear to have been the precursors of other Perciform Fishes. About 70

species, referred to 13 genera, are known to live at the present day,

mostly at great depths, in {656}the seas nearly all over the world. But one

freshwater form is known, _Aphredoderus sayanus_, the little Pirate Perch

of North America, growing to 5 inches in length. The largest marine forms

(_Beryx_ and _Gephyroberyx_) measure from 1 to 2 feet.

Recent genera: _Beryx_, _Polymixia_, _Aphredoderus_, _Melamphaes_,

_Plectromus_, _Scopelogadus_, _Anoplogaster_, _Caulolepis_, _Trachichthys_,

_Paratrachichthys_, _Gephyroberyx_, _Myripristis_, _Holocentrum_.

[Illustration: FIG. 401.—_Hoplopteryx lewesiensis_. (Restored by A. S.

Woodward.)]

Fossil genera: _Sphenocephalus_, _Acrogaster_, _Pycnosterinx_,

_Hoplopteryx_, from the Upper Cretaceous. _Asineops_, from the Eocene of

North America, is supposed to be allied to _Aphredoderus_. _Beryx_ is

represented by several species in the Upper Cretaceous, and _Holocentrum_

occurs in the Eocene and Miocene.

FAM. 2. MONOCENTRIDAE.—The single genus _Monocentris_, with two species,

one from the seas of Japan, China, and India, and one from the South

Pacific, is very nearly related to the Berycidae, but differs in the

absence of ribs on the anterior six vertebrae, in the very large bony

scales, forming together a coat of mail, and in the structure of the

ventral fin, which is reduced to a strong spine and two or three very short

soft rays. The spines of the dorsal fin are very strong and isolated.

FAM. 3. PEMPHERIDAE.—The resemblance which the fishes united under this

family bear to _Beryx_ is very striking, and applies to the skeleton as

well as to the external characters. But the ventral fins are formed of one

spine and five soft rays, as in most Acanthopterygians. _Bathyclupea_

agrees with _Beryx_ in {657}being possessed of an open duct to the

air-bladder. About twelve species are known, referable to four genera:

_Pempheris_, _Parapriacanthus_, _Neopempheris_, from the Indian, Pacific,

and tropical Atlantic Oceans, and the deep-sea _Bathyclupea_, from the

Indian and Caribbean Seas, at depths of 145 to 419 fathoms.

[Illustration: FIG. 402.—_Pempheris muelleri_. (After Jordan and

Evermann.)]

FAM. 4. CENTRARCHIDAE.—No subocular lamina of the suborbitals, or subocular

shelf; entopterygoid present; palate toothed; teeth conical. Praecaudal

vertebrae with transverse processes from the third or fourth to the last;

ribs mostly sessile, behind the transverse processes. Two nostrils on each

side. Gill-membranes free from isthmus; 5 to 7 branchiostegal rays; gills

4, a slit behind the fourth; pseudobranchiae more or less developed, often

rudimentary or absent. Lower pharyngeal bones separate. Soft portion of

dorsal fin not more developed than the anal. Carnivorous freshwater fishes,

some entering brackish water. Many are known to build nests. Mostly

inhabitants of North America, the best known being the Sun-Fishes

(_Lepomis_), and Black Bass (_Micropterus_), several species of which have

recently been introduced into continental Europe. Principal genera:

_Pomoxys_, _Centrarchus_, _Ambloplites_, _Chaenobryttus_, _Micropterus_,

_Lepomis_, _Elassoma_, _Kuhlia_. Thirty-two species are known.

FAM. 5. CYPHOSIDAE.—Herbivorous fishes, agreeing in their essential

osteological characters with the preceding, differing in the incisor-like

outer teeth and densely-scaled fins. Some 14 species are known, from the

Pacific and Indian Oceans, referable to 4 genera: _Cyphosus_

(_Pimelepterus_), _Hermosilla_, _Sectator_, _Medialuna_.

{658}FAM. 6. LOBOTIDAE.—As in Centrarchidae, but transverse processes of

vertebrae very short, and palate toothless. Two genera: _Lobotes_, with two

species from the warm parts of the Indian and Pacific Oceans, the

Mediterranean, and the Atlantic coast of America, and _Datnioides_, with

two species from the estuaries of the Ganges and the rivers of Burma, Siam,

and the Malay Peninsula and Archipelago.

FAM. 7. TOXOTIDAE.—No subocular shelf; entopterygoid present; palate

toothed; mouth very protractile; maxillary very slender. Ribs sessile,

behind parapophyses which commence from the third vertebra. Two nostrils on

each side. Gill-membranes free from isthmus; 7 branchiostegal rays; gills

4, a slit behind the fourth; pseudobranchiae present. Lower pharyngeal

bones separate. Ventral fins with 1 spine and 5 soft rays.

A single genus, _Toxotes_, with 5 species from the fresh waters and coasts

of the East Indies, N. Australia, Polynesia, and New Zealand. _Toxotes

jaculator_ derives its name from its habit of capturing insects flying near

the surface of the water by shooting drops of water at them, a habit which

it continues in captivity.

FAM. 8. NANDIDAE.—No subocular shelf; no entopterygoid; palate toothed;

mouth very protractile. Praecaudal vertebrae with parapophyses from the 7th

or 8th; ribs mostly sessile, behind the parapophyses. Two nostrils on each

side. Gill-membranes free from isthmus; 6 branchiostegal rays; gills 4, a

slit behind the fourth; pseudobranchiae absent. Lower pharyngeal bones

separate. Soft portion of dorsal fin not more developed than the anal.

Ventral fins with 1 spine and 5 soft rays.

Small carnivorous freshwater fishes, of which 14 species are known,

referable to 6 genera: _Nandus_, _Catopra_, and _Badis_ from South-Eastern

Asia, _Polycentropsis_ from West Africa, _Polycentrus_ and _Monocirrus_

from South America.

FAM. 9. PERCIDAE.—No subocular lamina of the suborbitals; entopterygoid

present. Anterior vertebrae without transverse processes; all or most of

the ribs inserted on the transverse processes when these are developed. Two

nostrils on each side. Mouth not or but feebly protractile. Gill-membranes

free from the isthmus; 6 to 8 branchiostegal rays; gills 4, a slit behind

the fourth; pseudobranchiae more or less developed, often rudimentary,

rarely absent. Lower pharyngeal bones separate. Soft portion of dorsal fin

not very much more developed than {659}the anal; latter with 1 or 2 spines

only. Ventrals with 1 spine and 5 soft rays.

Embrace about 90 species from the freshwaters of the Northern Hemisphere,

referable to 12 genera: _Perca_, _Lucioperca_, _Percina_, _Etheostoma_,

_Boleosoma_, _Ulocentra_, _Diplesium_, _Ammocrypta_, _Crystallaria_,

_Aspro_, _Percarina_, _Acerina_. The British representatives of this family

are the Perch (_Perca fluviatilis_) and the Pope (_Acerina cernua_). The

largest forms are the Pike-Perches or Sander (_Lucioperca_) of Eastern

Europe, Western Asia, and North America, which reach a length of 4 feet and

are highly valued for the table. The American Darters (_Etheostoma_ and

allies), on the other hand, are among the smallest fishes, but many are

remarkable for their brilliant coloration.

FAM. 10. ACROPOMATIDAE.—An ill-defined group of marine fishes, some

deep-sea, placed here provisionally as annectant between the Percidae and

the Serranidae (Pomatominae), differing from the latter in the absence of a

subocular shelf. Spinous dorsal short.

About 28 species, mostly from the Pacific Ocean, distributed in 9 genera:

_Propoma_, _Xenichthys_, _Xenocys_, _Synagrops_, _Malacichthys_,

_Acropoma_, _Melanostoma_, _Epigonus_ (_Telescops_), _Dinolestes_.

FAM. 11. SERRANIDAE.—Second suborbital with an internal lamina supporting

the globe of the eye; entopterygoid present; palate usually toothed.

Anterior vertebrae without transverse processes; all or most of the ribs

inserted on the transverse processes where these are developed. Two

nostrils on each side. Gill-membranes free from isthmus; 6 or 7

branchiostegal rays; gills 4, a slit behind the fourth; pseudobranchiae

usually present. Lower pharyngeal bones usually separate. Soft portion of

dorsal usually not much more developed than the anal. Ventral fins with 1

spine and 5 (rarely 4) soft rays.

One of the largest families of fishes. The principal genera may be grouped

as follows:—

SERRANINAE.—_Percichthys, Percilia, Lateolabrax, Niphon, Morone,

Percalates, Ctenolates, Macquaria, Siniperca, Coreoperca, Acanthistius,

Trachypoma, Centrogenys, Polyprion, Oligorus, Stereolepis, Dinoperca,

Liopropoma, Aulacocephalus, Plectropoma, Epinephelus, Cromileptes,

Paranthias, Serranus, Centropristes, Chelidoperca, Gilbertia, Caesioperca,

Caprodon, Anthias, Callanthias, Pseudoplesiops, Plesiops, Trachinops_.

{660}GRAMMISTINAE.—_Grammistes, Rhypticus_. PRIACANTHINAE.—_Priacanthus,

Pseudopriacanthus_. CENTROPOMINAE.—_Lates, Psammoperca, Centropomus_.

POMATOMINAE.—_Pomatomus, Scombrops_. AMBASSINAE.—_Ambassis_.

CHILODIPTERINAE.—_Chilodipterus, Apogon_. LUTJANINAE.—_Lutjanus,

Glaucosoma, Therapon, Hoplopagrus, Etelis, Aprion, Aphareus, Odontonectes_.

CIRRHITINAE.—_Cirrhites, Cirrhitichthys_. PENTACEROTINAE.—_Pentaceros,

Pentaceropsis, Histiopterus_.

The number of recent species amounts to about 550, the great majority of

which are marine.

[Illustration: FIG. 403.—Sea Perch (_Serranus cabrilla_). × ⅓. (After

Cuvier and Valenciennes.)]

The earliest fossil form is _Prolates_, from the Upper Cretaceous of

France. _Morone_, _Serranus_, _Percichthys_, _Anthias_, and _Apogon_ are

represented in Eocene and later strata.

The range of the family is almost cosmopolitan; few of the Marine Perches

descend to any great depth. Some of the species of _Stereolepis_ and

_Epinephelus_ grow to a length of 6 to 10 feet. Several species of

_Serranus_ (_S. cabrilla_, _S. scriba_, _S. hepatus_), inhabiting the

Mediterranean and neighbouring parts of the Atlantic, and some _Lutjanus_

are normally hermaphrodite. Some _Chilodipterus_ and _Apogon_ are

remarkable for their nursing habits, the male sheltering the eggs in his

mouth.

The curious genera _Anomalops_ and _Photoblepharon_, of each of which a

single species is known from the Malay Archipelago and the South Pacific,

have been made the types of a family, ANOMALOPIDAE, the systematic position

of which remains uncertain since the osteological characters have not been

examined. {661}They are remarkable for the movable flap below the eye,

bearing a luminous organ, the nature of which has recently been

investigated by Max Weber.[714]

FAM. 12. PSEUDOCHROMIDIDAE.—Closely allied to the Serranidae, and connected

with them through _Plesiops_ and its allies. Dorsal and anal fins elongate

and formed mostly of articulated soft rays, the spines being feeble and

few.

A. With two lateral lines: _Pseudochromis_, _Cichlops_.

B. With a single lateral line: _Opisthognathus_, _Latilus_, _Caulolatilus_,

_Lopholatilus_, _Malacanthus_, _Bathymaster_, _Rathbunella_.

[Illustration: FIG. 404.—Tile-Fish (_Lopholatilus chamaeleonticeps_). × ¼.

(After Goode and Bean.)]

Marine, mostly of small size, inhabiting the Atlantic, Indian, and Pacific

Oceans. About 30 species. One of the largest and best-known members of this

family is the Tile-Fish (_Lopholatilus chamaeleonticeps_), living upon the

bottom of what is known as the Gulf Stream slope, off the coast of New

England, where it was first observed in 1879. Here the water is normally

comparatively warm, coming as it does from the superheated region of the

Gulf of Mexico. During a series of unusually severe gales in 1882, this

mass of water was pushed aside, as it were, and replaced by colder water.

As a result, millions and millions of these fishes were killed, and their

dead bodies literally covered the surface of the sea for hundreds of square

miles. It was feared that the Tile-Fish was exterminated; this was not so,

however, and the fish has reappeared in tolerable abundance within the last

few years.

FAM. 13. CEPOLIDAE.—Agree in essential characters with the preceding, but

body band-like with very numerous vertebrae {662}(15 + 54), and very

elongate dorsal and anal fins formed of soft rays, of which all except the

first three dorsal and the first anal are articulated and branched.

Although these fishes have hitherto been placed near the Blenniidae, the

Gobiidae, or the Trachypteridae, they are nothing but extremely elongate

Perches, and they stand in the same relation to the Serranidae as the

Trichiuridae to the Carangidae and Scombridae. They hardly deserve to rank

as a family distinct from the Pseudochromididae.

[Illustration: FIG. 405.—_Cepola rubescens_. × ½. (After Cuvier and

Valenciennes.)]

Two genera, _Cepola_ and _Acanthocepola_, with 10 species, from the

Mediterranean and North-Eastern Atlantic, the Indian Ocean, and the Western

Pacific. The Band-Fish (_Cepola rubescens_), which is common in the

Mediterranean, is sometimes found on the British coasts; it grows to a foot

and a half in length, and is remarkable for its bright red colour.

FAM. 14. HOPLOGNATHIDAE.—Characters of Serranidae, but teeth fused to form

a beak as in _Tetrodon_; palate toothless.

_Hoplognathus_, with 4 species, from the Pacific Ocean.

FAM. 15. SILLAGINIDAE.—As in Serranidae, but soft dorsal and anal much

elongate, as in Pseudochromididae, from which the Sillaginidae differ in

the separate spinous dorsal. Palate toothed. Connecting the Serranidae and

the Sciaenidae.

Small Marine Fishes from the Indian and Pacific Oceans, ascending rivers. A

single genus, _Sillago_, with about 10 species.

{663}FAM. 16. SCIAENIDAE.—Also closely related to the Serranidae. Dorsal

fin with a short spinous and a long soft portion; anal much shorter than

the latter. Palate usually toothless.

A large family of about 150 species, mostly marine. Principal genera:

_Arripis, Sciaena, Corvina, Otolithus, Ancylodon, Nebris, Larimus,

Pogonias, Haplonotus, Umbrina, Eques_.

Many of these fishes reach a large size, and the flesh of nearly all is

esteemed. The Meagre (_Sciaena aquila_) is sometimes taken on our coast.

The Drum (_Pogonias chromis_) so called from the sounds which it produces,

in common with many other Sciaenids, is remarkable for having the lower

pharyngeal bones united, as is also the case in the North American

freshwater genus _Haplonotus_. The air-bladder is usually large and

complicated, provided with more or less numerous appendages.

FAM. 17. GERRIDAE.—Agree in the character of the vertebral column with the

Serranidae, but differ in the absence of a subocular shelf; the very

protractile mouth usually descends when protruded and the praemaxillary

emits an upward lateral process; palate toothless; lower pharyngeal bones

usually large and more or less completely coalesced.

About 60 species of carnivorous, mostly small, fishes, from the tropical

seas, referable to 3 genera: _Gerres, Equula, Gazza_.

FAM. 18. LACTARIIDAE.—Intermediate between Serranidae and Trichodontidae.

No subocular shelf; palate toothed; branchiostegal rays 7; scales small,

cycloid, deciduous; spinous dorsal short; anal longer than the soft dorsal;

scapula with two foramina.

_Lactarius delicatulus_, from the coasts of Southern Asia.

FAM. 19. TRICHODONTIDAE.—Agree in the character of the vertebral column

with the Serranidae, but have no subocular shelf; body naked, and anal much

longer than the soft dorsal; palate toothless; only 5 branchiostegal rays.

Two genera, each with a single species, from the North Pacific, _Trichodon_

and _Arctoscopus_, bearing some resemblance to the Trachinidae, with which

they have usually been associated.

FAM. 20. LATRIDIDAE.—Marine Fishes intermediate between the Serranidae and

the Haplodactylidae, agreeing with the former in the extent of the anal

fin, which is nearly as long as the soft dorsal, and with the latter in the

absence of a subocular shelf and the posterior position of the ventrals. A

single genus, _Latris_, with 3 or 4 species, from the coasts of Australia

and New Zealand.

{664}FAM. 21. HAPLODACTYLIDAE.—No subocular shelf; entopterygoid present;

palate usually toothless. Vertebrae with transverse processes from the

third or fourth; all the ribs attached to the transverse processes when

these are present; anterior epipleurals strong. Two nostrils on each side.

Gill-membranes free from the isthmus; 5 or 6 branchiostegal rays; gills 4,

a slit behind the fourth; pseudobranchiae present. Lower pharyngeal bones

separate. Soft portion of the dorsal fin much more developed than the anal.

Ventral fins with 1 spine and 5 soft rays, inserted far back behind the

pectorals, the lower rays of which are simple and more or less thickened.

This family embraces the genera _Haplodactylus, Chilodactylus, Chironemus_,

and _Threpterius_, with some 30 species from the seas of the Southern

Hemisphere and Japan. They feed chiefly on crustaceans, molluscs, and other

invertebrates living among sea-weed.

FAM. 22. PRISTIPOMATIDAE.—No subocular shelf; entopterygoid present; palate

toothless. Vertebrae with transverse processes from the third; all the ribs

attached to the transverse processes. Two nostrils on each side.

Gill-membranes free from isthmus; 5 to 7 branchiostegal rays; gills 4, a

slit behind the fourth; pseudobranchiae present. Lower pharyngeal bones

separate. Ventral fins with 1 spine and 5 soft rays.

_Pristipoma, Haemulon, Diagramma_, and _Pentapus_, distributed over all the

tropical and subtropical seas, a few entering fresh waters. About 130

species are known.

FAM. 23. SPARIDAE.—Second suborbital with an internal lamina supporting the

globe of the eye; entopterygoid present; palate usually toothless; teeth

often either cutting in front, or molar-like on the sides. Vertebrae with

transverse processes from the second or third; all the ribs attached to the

transverse processes. Two nostrils on each side. Gill-membranes free from

isthmus; 5 to 7 branchiostegal rays; gills 4, a slit behind the fourth;

pseudobranchiae present. Lower pharyngeal bones separate. Soft portion of

dorsal fin not much more developed than the anal. Ventral fins with 1 spine

and 5 soft rays.

The Sea-Breams embrace some 200 species, distributed over the coasts of

nearly the whole world. Some are herbivorous, but the majority are

carnivorous.

Principal genera: _Scolopsis, Dentex, Synagris, Caesio, Maena, Oblata,

Melambaphes, Girella, Doydixodon, Cantharus, Box_, {665}_Crenidens,

Pachymetopon, Dipterodon, Sargus, Charax, Lethrinus, Sphaerodon, Sparus,

Pagrus, Pagellus_.

Abundantly represented in Eocene and Miocene beds by remains of _Sargus,

Sparus, Pagrus, Pagellus_, and by the extinct genera _Ctenodentex,

Sparnodus_, and _Trigonodon_. Some species grow to a length of three feet,

such as the "Sheep's-Head" of North America, one of the best salt-water

fishes of the United States, and the "Schnapper" (_Sparus unicolor_), of

Australia, also much esteemed. Some of the Atlantic and Mediterranean

species of _Box, Sargus, Charax, Sparus_, and _Pagellus_ are known to be

normally, or at least very frequently, hermaphrodite.

[Illustration: FIG. 406.—Gilt-head Sea-Bream (_Pagrus auratus_). A, its

dentition. (After Cuvier and Valenciennes.)]

FAM. 24. MULLIDAE.—The "Red Mullets" are very nearly related to the

Sparidae, with which they agree in the structure of the vertebral column

and the presence of a subocular shelf. They differ in the very weak

dentition, the presence of a pair of hyoid barbels, the reduced number (4)

of branchiostegal rays, and the double perforation of the scapula. Two

short dorsal fins, remote from each other, the anterior with weak spines.

Small marine and brackish-water fishes, feeding on animalcules and

decomposing matter; inhabitants of nearly all the tropical seas and

extending to Northern Europe. About 50 species are known, referred to 5

genera: _Upeneoides, Upeneichthys, Mullus, Mulloides_, and _Upeneus_.

{666}The British species are _Mullus barbatus_ and _M. surmuletus_,

remarkable for their beautiful pink or red colour, and much valued on the

market, although no longer held in the high estimation for which they were

noted by the Romans.

[Illustration: FIG. 407.—Scapular arch of _Mullus surmuletus_. _cl_,

Clavicle; _cor_, coracoid; _pt_, pterygials; _ptcl_, post-clavicle; _pte_,

post-temporal; _sc_, scapula; _scl_, supra-scapula.]

FAM. 25. SCORPIDIDAE.—Second suborbital with an internal lamina supporting

the globe of the eye; entopterygoid present; palate toothed. Ribs sessile,

behind the parapophyses when these are present. Two nostrils on each side.

Gill-membranes free from isthmus; 7 branchiostegal rays; gills 4, a slit

behind the fourth; pseudobranchiae present. Lower pharyngeal bones

separate. Ventral fins, if present, with 1 spine and 5 soft rays.

This family embraces 12 species from the coasts of Africa, Southern Asia,

Australia, and New Zealand, referable to 5 genera: _Scorpis_,

_Atypichthys_, _Atyposoma_, _Henoplosus_, _Psettus_. The fish here figured

(_Psettus sebae_, Fig. 408) is remarkable for the excessive depth of the

body, which is greater than in any other species.

_Aipichthys_, one of the few Acanthopterygian types known to have existed

in the Cretaceous period, appears to belong to the family Scorpididae as

here defined, and not to the Carangidae.

FAM. 26. CAPROIDAE.—Characters of Scorpididae, but supratemporal completely

ankylosed to the skull.

The Boar-Fish (_Capros aper_) of the Atlantic and Mediterranean is

occasionally found on our southern coasts, and is highly remarkable for the

hair-like bristles with which its scales are {667}covered, an extreme

exaggeration of the "Ctenoid" type. The mouth is very protractile, and the

vertebrae are only 22 or 23 in number. _Antigonia_, with a single species

found at remote points in the Atlantic, Pacific, and Indian Oceans, is

probably allied to _Capros_, with which it is believed to be connected

through the fossil genus _Proantigonia_, from the Upper Miocene of Croatia.

[Illustration: FIG. 408.—_Psettus sebae_, from the West Coast of Africa, ×

½.]

FAM. 27. CHAETODONTIDAE.—Closely allied to and evidently derived from the

more generalised types of the Scorpididae, differing in the attachment of

the gill-membranes to the isthmus. Post-temporal more or less firmly united

with the skull, sometimes indistinctly bifurcate. Mouth small; palate

toothless; soft portions of vertical fins usually covered with scales; ribs

usually strong and blade-like; body short and deep.

A large group of about 200 marine carnivorous fishes from the tropics,

mostly of small size, remarkable for their singular forms and markings and

brilliant coloration. They are particularly abundant about volcanic rocks

and coral reefs.

{668}An Atlantic species of _Ephippus_ (_E. faber_) is extremely

remarkable, when adult, for an enormously enlarged globular bony mass on

the back of the head, formed by hypertrophy of the frontal and

supraoccipital bones.

Principal genera: _Ephippus, Parapsettus, Scatophagus, Chaetodon, Chelmo,

Heniochus, Holacanthus, Pomacanthus, Platax_.

_Chaetodon, Holacanthus, Pomacanthus, Scatophagus, Ephippus_, and _Platax_

were represented in the Eocene of Europe.

FAM. 28. DREPANIDAE.—The genus _Drepane_, with a single species from the

Indian Ocean, is very closely related to the Chaetodontidae, but it lacks

the subocular shelf, and it is distinguished externally by the very

elongate, falciform pectoral fin.

FAM. 29. ACANTHURIDAE.—A more or less developed subocular shelf;

entopterygoid present. Mouth very small, not or but slightly protractile,

the maxillary more or less firmly attached or ankylosed to the

praemaxillary; teeth conical, bristle-like, or incisor-like. Palate

toothless. Vertebrae 22 or 23, the praecaudals with strong transverse

processes commencing from the first; ribs and epipleurals inserted on the

transverse processes. Post-temporal not distinctly forked, ankylosed to the

skull. Two nostrils on each side. Gill-membranes broadly attached to the

isthmus; 4 or 5 branchiostegal rays; gills 4, a slit behind the fourth;

pseudobranchiae present. Lower pharyngeal bones separate. Body covered with

minute, often rough scales. Dorsal and anal fins elongate, with more or

less strong spines. Ventrals with 1 spine and 2 to 5 soft rays.

A family of about 80 species, mostly herbivorous, from the tropical seas,

referred to 6 genera: _Zanclus, Ctenochaetus, Acanthurus, Colocopus,

Prionurus, Naseus_. They form a connecting link between the Chaetodontidae

and the Plectognathi.

Remains from the Eocene of Europe have been referred to _Zanclus,

Acanthurus_, and _Naseus_, and to the extinct genera _Aulorhamphus_ and

_Apostasis_.

FAM. 30. TEUTHIDIDAE.—No subocular shelf; entopterygoid present. Mouth very

small, beak-like, not protractile, with incisor-like teeth; maxillary

ankylosed to the praemaxillary. Palate toothless. Two nostrils on each

side. Gill-membranes broadly attached to the isthmus; 5 branchiostegal

rays; gills 4, a slit behind the fourth; pseudobranchiae present. Lower

pharyngeal bones separate. Supratemporal forked. Vertebrae {669}23, with

sessile ribs and no parapophyses, the epipleurals inserted on the ribs.

Body covered with very small scales. Vertical fins elongate, with strong

spines, 6 or 7 in the anal. Ventrals with 2 spines and 3 soft rays between

them.

A single recent genus, _Teuthis_, with about 30 species, herbivorous fishes

from the Indian and Western Pacific Oceans. According to Bottard[715] the

sting from the spines of these fishes is much dreaded. _Archaeoteuthis_,

from the Oligocene of Switzerland.

FAM. 31. OSPHROMENIDAE.—Second suborbital with a more or less developed

internal lamina; entopterygoid present; palate toothed. Most of the

praecaudal vertebrae with transverse processes, to which the ribs are

attached. Two nostrils on each side. Gill-membranes attached to isthmus; 4

to 6 branchiostegal rays; gills 4, a slit behind the fourth;

pseudobranchiae absent. Lower pharyngeal bones separate. Vertical fins very

variable in extent, the spines sometimes very numerous, sometimes absent.

Ventral fins with not more than 5 soft rays, sometimes reduced to a

filamentous ray. A superbranchial respiratory organ, situated in a cavity

above the gills.

Freshwater fishes having much in common with the Anabantidae, and likewise

confined to South-Eastern Asia and Africa. Only 22 species are known,

referable to 7 genera: _Helostoma_, _Polyacanthus_, _Osphromenus_,

_Trichogaster_, _Luciocephalus_, _Betta_, and _Micracanthus_. The latter,

the only African representative of the family (one species from the Ogowe),

hardly differs from the Malay genus _Betta_. Most of the Osphromenidae are

notable as aquarium fishes. The largest species, the Gourami (_Osphromenus

olfax_), growing to a length of 2 feet, from the Malay Archipelago, is one

of the best flavoured fishes of the Far East and has been acclimatised in

India, the Guianas, and Mauritius. A domesticated variety of the Chinese

_Polyacanthus opercularis_, known as _Macropodus viridi-auratus_,

remarkable for the beauty of its form and colour, readily breeds in our

aquariums. Like the Gourami, the male constructs a nest of air-bubbles,

strengthened by a buccal secretion, and watches over the eggs and young.

The little _Betta pugnax_, from South-Eastern Asia, derives its name from

its excitable nature, which causes specimens to be kept by the Siamese in

glass vessels where they engage in fights, special breeds being cultivated

for the purpose. According to Cantor, {670}the Siamese in 1840 were as

infatuated with the combats of these fishes as the Malays are with their

cock-fights, and the licence to exhibit them was farmed, bringing in a

considerable annual revenue to the king.

FAM. 32. EMBIOTOCIDAE.—Second suborbital with an internal lamina supporting

the globe of the eye; entopterygoid present; palate toothless. Ribs

sessile, above and behind the parapophyses, where these are present. Two

nostrils on each side. Gill-membranes free from isthmus; 5 or 6

branchiostegal rays; gills 4, a slit behind the fourth; pseudobranchiae

present. Lower pharyngeals united, with conical or pavement-like teeth.

Anal fin, with three spines. Ventral fins with 1 spine and 5 soft rays.

[Illustration: FIG. 409.—_Ditrema temminckii_, from Japan. × ⅓. (After

Jordan.)]

Small or moderate-sized fishes inhabiting California and Japan, mostly

marine, one species, however, inhabiting fresh waters, whilst another

descends to a great depth. They feed mostly on crustaceans, but one genus

(_Abcona_) is herbivorous. The name "Surf-Fishes," by which they are

generally known, refers to the fact that most species are found in the surf

along sandy beaches. All are viviparous in the strictest sense of the term,

the young remaining for a long time closely packed in a sac-like

enlargement of the oviduct analogous to a uterus; they are of relatively

large size at birth, and quite similar in form to the parent, whilst at an

earlier period they differ in having the vertical fins much more elevated.

Twenty-four species are known.[716] Principal genera: _Hysterocarpus_,

_Abcona_, _Cymatogaster_, _Embiotoca_, _Ditrema_.

FAM. 33. CICHLIDAE.—No subocular shelf; entopterygoid {671}present; palate

toothless; lower pharyngeal bones more or less completely united, with

median suture. Vertebrae with parapophyses from the third; ribs most

frequently sessile or subsessile. A single nostril on each side.

Gill-membranes free from isthmus; 5 or 6 branchiostegal rays; gills 4, a

slit behind the fourth; pseudobranchiae absent. Dorsal fin, with numerous

spines; anal with 3 spines or more. Ventral fins with 1 spine and 5 soft

rays.

[Illustration: FIG. 410.—_Tilapia dardennii_, from Lake Tanganyika. ⅓ nat.

size.]

Fresh or brackish-water fishes, variable in form and dentition, some

carnivorous, others chiefly herbivorous. In some American forms (_Cichla_)

the males and females differ during the spawning season, the male

developing a hump on the top of the head, which disappears afterwards. The

eggs and young are cared for by the parents; either the male or the female,

according to the species, sheltering them in the mouth or pharynx.[717]

These fishes, often designated as "Chromides," a name which properly

pertains to members of the following family, inhabit Africa, Madagascar,

Syria, India and Ceylon, and Central and South America, from Texas to

Uruguay. About 45 genera are distinguished, based mostly on the number of

anal spines and the dentition, which for variety of types is comparable to

that of the Characinidae. Of these 45 genera, 30 are African. 150 species

are known from Africa (with Syria and Madagascar), 140 from America, and 3

from India and Ceylon.[718] Principal genera—African: _Lamprologus_,

_Hemichromis_, _Paratilapia_, _Xenotilapia_, _Tropheus_, _Tilapia_,

{672}_Asprotilapia_, _Eretmodus_, _Plecodus_, _Pseudetroplus_. American:

_Acara_, _Heros_, _Hygrogonus_, _Cichla_, _Crenicichla_, _Chaetobranchus_,

_Geophagus_, _Symphysodon_, _Pterophyllum_. Indian: _Etroplus_.

No part of the world surpasses Lake Tanganyika in variety of generic and

specific types of Cichlidae, the fish-fauna of this great lake being in

great majority made up of members of this family.

[Illustration: FIG. 411.—Distribution of the Cichlidae.]

_Priscacara_, from the Eocene of North America, is the only extinct genus

which can be referred to this family.

FAM. 34. POMACENTRIDAE.—A subocular shelf; entopterygoid present; palate

toothless; teeth conical or incisor-like; lower pharyngeals completely

united into one bone. Vertebrae with transverse processes from the fourth

or fifth; ribs inserted on the transverse processes, when these are

present. A single nostril on each side. Gill-membranes free from the

isthmus; 5 to 7 branchiostegal rays; gills 3½; pseudobranchiae present.

Dorsal fin elongate, with numerous strong spines; anal with 2 spines only.

Ventral fins with 1 spine and 5 soft rays.

Small fishes of the tropical and warm seas, resembling the Chaetodontidae

in form and mode of life, likewise usually of brilliant coloration; in

structural characters intermediate between the Cichlidae and the Labridae.

They feed chiefly on small marine animals, but the species with

incisor-like teeth are entirely or mainly herbivorous. Over 150 species are

known.

Principal genera: _Heliastes_, _Azurina_, _Amphiprion_, _Premnas_,

_Dascyllus_, _Pomacentrus_, _Glyphidodon_, _Microspathodon_.

{673}The family is supposed to be represented in the Upper Eocene and Lower

Miocene of Italy by the extinct genus _Odonteus_.

FAM. 35. LABRIDAE.—No subocular shelf; entopterygoid present; palate

toothless; anterior teeth of the jaws usually strong and canine-like,

lateral teeth often soldered at the base; lower pharyngeals completely

united into one bone, with conical or tubercular teeth. Vertebrae with

transverse processes from the third; all the ribs attached to the

transverse processes. Lips thick. Two nostrils on each side. Gill-membranes

free or joined to the narrow isthmus; 5 or 6 branchiostegal rays; gills

three and a half; pseudobranchiae present. Dorsal fin elongate, with

numerous, usually slender, spines. Ventral fins with 1 spine and 5 soft

rays.

The "Wrasses" form a large family of mostly brilliantly coloured marine

fishes, inhabiting all the tropical and temperate coasts. Their regime is

partially herbivorous, partially carnivorous. About 400 species are known.

Principal genera: _Labrus_, _Tautoga_, _Malacopterus_, _Ctenolabrus_,

_Chaerops_, _Platychaerops_, _Heterochaerops_, _Labrichthys_, _Cossyphus_,

_Cirrhilabrus_, _Chilinus_, _Epibulus_, _Anampses_, _Platyglossus_,

_Novacula_, _Julis_, _Gomphosus_, _Chilio_, _Coris_.

[Illustration: FIG. 412.—Upper and lower pharyngeal bones of _Labrus

maculatus_.]

Some of the members of this family have been observed to build nests for

the protection of their eggs and young. These nests, in the European

_Labrus_, are made of seaweeds, zoophytes, corals, broken shells, etc., and

are the work of both the male and the female.[719] It is also in this

family that sleep was first observed in fishes, and this has been fully

verified by Möbius[720] {674}on _Labrus rupestris_ in an aquarium, the fish

seeking a sleeping place at night and laying itself down to rest on one

side.

As first pointed out by Günther, the Labridae found in temperate regions

have a higher number (30 to 41) of vertebrae than those inhabiting the

tropics (23 to 29), a rule which applies more or less to other families of

Acanthopterygians. Remains of _Labrus_ and _Julis_ occur in the Eocene and

Miocene of Europe. An allied fossil genus, _Labrodon_, is represented by

numerous species in Tertiary beds of Europe and North America. _Phyllodus_,

_Egertonia_, _Platylaemus_, and _Pseudosphaerodon_, from the Eocene and

Miocene, are referred, with doubt, to this family.

FAM. 36. SCARIDAE.—Closely allied to the preceding, with which they have

usually been united, but differing in the more or less coalescent teeth,

forming often a parrot-like beak, the lower pharyngeals united into a

concave or spoon-shaped bone with flat, tessellated teeth; and in the

development of transverse processes from the first vertebra. Vertebrae 24

or 25.

[Illustration: FIG. 413.—Upper and lower pharyngeal bones of _Scarus

strongylocephalus_. (After Jordan and Evermann.)]

Curious, mostly brilliantly-coloured fishes of the tropical seas and the

Mediterranean, especially abundant about coral-reefs. "Parrot-Wrasses" feed

mostly on vegetable matter, corals, and on hard-shelled Mollusca, for

crushing which their dentition is well adapted. The largest reach a length

of 4 feet. Some are much valued as food, whilst others are reputed

poisonous. About 110 species are known, referable to 8 genera:

_Cryptotomus_ (_Calliodon_), _Calotomus_, _Sparisoma_, _Scarus_,

_Pseudoscarus_, _Odax_, _Coridodax_, _Siphonognathus_. The latter is very

aberrant in shape, the head and body resembling those of a Pipe-Fish.

_Scarus_ is reported from the Eocene and Miocene of Europe.

{675}DIVISION II.—SCOMBRIFORMES.

No bony stay for the praeopercle. Spinous dorsal, if distinct, formed of

short or feeble, slender spines. Epipleurals usually attached to the centra

when ribs are sessile, or to the parapophyses of the vertebrae, rarely to

the ribs. Pectoral arch similar to that of the Perciformes, but pterygials

sometimes more abbreviated. Ventral fins thoracic. Caudal fin, if well

developed, with very numerous rays deeply forked at the base.

[Illustration: FIG. 414.—Caudal fin of _Sarda orientalis_. _h.s_, Hypural

spine.]

Although bound by natural ties, the series of families that cluster round

the Mackerel offer so many modifications of structure that it is almost

impossible to draw up a diagnosis differentiating every one of its members

from the Perciformes, with which they are closely connected, and from which

they hardly deserve to be separated. Even after removing many genera which

have been united with them by my predecessors, and which will now be found

scattered among various groups of the system, no good definition of the

Scombriformes can be given. The Mackerel and Horse-Mackerel are taken as

the pattern-forms around which more or less aberrant types are located,

types yet not so aberrant as to be traced back to these familiar forms

through a number of intermediate grades. As {676}regards external features,

it may be stated that the dorsal and anal spines, if present, are either

weak and slender, or, if strong, short and detached; the caudal peduncle is

constricted, and the caudal fin, if well developed, is usually deeply

forked, and with the forked bases of the very numerous rays much longer

than in most of the Perciformes, embracing at least a considerable portion

of the expanded hypural bones, a character by which the Chaetodontidae,

Acanthuridae, and several extinct types which have been placed with the

Carangidae are at once excluded. All are carnivorous and marine, and many

are pelagic and of very wide distribution. No praetertiary members of this

division, as here defined, have yet been found.

SYNOPSIS OF THE FAMILIES

I. Praemaxillaries more or less protractile, not beak-like; scales small

or absent, sometimes with enlarged lateral scutes; spinous dorsal

fin short or replaced by a series of isolated spines; anal usually

with one or two spines detached from the rest of the fin.

Praecaudal vertebrae with transverse processes behind which the ribs

are attached 1. _Carangidae_.

Praecaudal vertebrae without well-developed parapophyses, ribs and

epipleurals inserted close together on the centra

2. _Rhachicentridae_.

II. Praemaxillaries not protractile; scales usually small or absent;

body more or less elongate; dorsal fin elongate, single or divided,

without free spines; no free anal spines.

A. Pseudobranchiae present.

Vertebrae without transverse processes; soft dorsal fin longer than

the spinous; pectoral fins high up the sides 3. _Scombridae_.

Vertebrae without transverse processes; soft dorsal fin shorter than

the spinous, if the latter be distinct; pectoral fins low down

the sides 4. _Trichiuridae_.

Vertebrae without transverse processes; snout produced into a spear

5. _Histiophoridae_.

Vertebrae with transverse processes bearing the ribs; snout produced

into a sword; no ventrals 6. _Xiphiidae_.

Vertebrae without transverse processes; gill-membranes attached to

isthmus; dorsal and anal fins formed of unarticulated, widely set

rays; dentition very feeble 7. _Luvaridae_.

B. Pseudobranchiae absent; no well-developed transverse processes to

the praecaudal vertebrae; the ribs and the epipleurals inserted

close together on the centra; snout short and very deep

8. _Coryphaenidae_.

III. Praemaxillaries not protractile, or if slightly protractile,

scales large; dorsal and anal fins elongate, without distinct spinous

division; most of the praecaudal vertebrae with strong haemapophyses,

to which the ribs are attached 9. _Bramidae_.

{677}FAM. 1. CARANGIDAE.—Praemaxillaries more or less protractile.

Vertebrae 24 to 26; ribs behind the parapophyses; epipleurals on the

parapophyses, rarely on the ribs.[721] Body covered with small scales, or

naked, often with enlarged scutes on each side of the body or of the tail;

dorsal spines few, or slender or rudimentary; a more or less developed

spine adnate to the soft portion of the anal, often preceded by a pair of

spines separated from the rest of the fin. Pseudobranchiae usually present.

Inhabitants of the seas of the temperate and tropical regions, many of the

species having a very wide range. About 150 species are known.