Chapter XXI: The Fishes of the Deep Sea (8)

Three species from the Cape of Good Hope, South Australia, New Zealand, and Chili are known. They grow to a length of five feet, and have an excellent flesh, like cod, well adapted for curing. At the Cape they are known by the name of “Klipvisch,” and in New Zealand as “Ling” or “Cloudy Bay Cod.”

III. _No ventral fins whatever; vent at the throat_: FIERASFERINA.

These fishes (_Fierasfer_ and _Encheliophis_) are of very small size and eel-like in shape; the ten species known are found in the Mediterranean, Atlantic, and Indo-Pacific. As far as is known they live parasitically in cavities of other marine animals, accompany Medusæ, and more especially penetrate into the respiratory cavities of Star-fishes and Holothurians. Not rarely they attempt other animals less suited for their habits, as, for instance, Bivalves; and cases are known in which they have been found imprisoned below the mantle of the Mollusk, or covered over with a layer of the pearly substance secreted by it. They are perfectly harmless to their host, and merely seek for themselves a safe habitation, feeding on the animalcules which enter with the water the cavity inhabited by them.

IV. _No ventral fins whatever; vent remote from the head; gill-openings very wide, the gill-membranes not being united_: AMMODYTINA.

The “Sand-eels” or “Launces” (_Ammodytes_) are extremely common on sandy shores of Europe and North America. They live in large shoals, rising as with one accord to the surface, or diving to the bottom, where they bury themselves with incredible rapidity in the sand. They are much sought after for bait by fishermen, who discover their presence on the surface by watching the action of Porpoises which feed on them. These Cetaceans, when they meet with a shoal, know how to keep it on the surface by diving below and swimming round it, thus destroying large numbers of them. The most common species on the British coast is the Lesser Sand-eel (_A. tobianus_); the Greater Sand-eel (_A. lanceolatus_), which attains to a length of eighteen inches; _A. siculus_, from the Mediterranean, scarcer in British seas. Two species live on the American coasts, _A. americanus_ and _A. dubius_; one in California, _A. personatus_. _Bleekeria_ from Madras is the second genus of this group.

V. _No ventral fins whatever; vent remote from the head; gill-openings of moderate width, the gill-membranes being united below the throat, not attached to the isthmus_: CONGROGADINA.

Only two fishes belong to this group--_Congrogadus_ from the Australian coasts, and _Haliophis_ from the Red Sea.

FOURTH FAMILY--MACRURIDÆ.

_Body terminating in a long, compressed, tapering tail, covered with spiny, keeled, or striated scales. One short ante__rior dorsal; the second very long, continued to the end of the tail, and composed of very feeble rays; anal of an extent similar to that of the second dorsal; no caudal. Ventral fins thoracic or jugular, composed of several rays._

This family, known a few years ago from a limited number of examples, representing a few species only, proves to be one which is distributed over all oceans, occurring in considerable variety and great abundance at depths of from 120 to 2600 fathoms. They are, in fact, Deep-sea Gadoids, much resembling each other in the general shape of their body, but differing in the form of the snout and in the structure of their scales. About forty species are known, of which many attain a length of three feet. They have been referred to the following genera:--

MACRURUS.--Scales of moderate size; snout produced, conical;
mouth inferior.

CORYPHÆNOIDES.--Scales of moderate size; snout obtuse, obliquely
truncated; cleft of the mouth lateral.

MACRURONUS.--Scales of moderate size, spiny; snout pointed;
mouth anterior and lateral, with the lower jaw projecting.

MALACOCEPHALUS.--Scales very small, ctenoid; snout short,
obtuse, obliquely truncated.

BATHYGADUS.--Scales small, cycloid; snout not projecting beyond
the mouth; mouth wide, anterior, and lateral.

_Ateleopus_ from Japan and _Xenocephalus_ from New Ireland are genera belonging to the Gadoid Anacanths, but are very imperfectly known.

SECOND DIVISION--ANACANTHINI PLEURONECTOIDEI.

_Head and part of the body unsymmetrically formed._

This division consists of one family only:

PLEURONECTIDÆ.

The fishes of this family are called “Flat-fishes,” from their strongly compressed, high, and flat body; in consequence of the absence of an air-bladder, and of the structure of their paired fins, they are unable to maintain their body in a vertical position, resting and moving on one side of the body only. The side turned towards the bottom is sometimes the left, sometimes the right, colourless, and termed the “blind” side; that turned upwards and towards the light is variously, and in some tropical species even vividly, coloured. Both eyes are on the coloured side, on which side also the muscles are more strongly developed. The dorsal and anal fins are exceedingly long, without division. All the Flat-fishes undergo remarkable changes with age, which, however, are very imperfectly known and not yet fully understood, from the difficulty of referring larval forms to their respective parents. The larvæ are, singularly enough, much more frequently met in the open ocean than near the coast; they are transparent, like _Leptocephali_; perfectly symmetrical, with an eye on each side of the head, and swim in a vertical position like other fishes. The manner in which one eye is transferred from the blind to the coloured side is subject to discussion. Whilst some naturalists believe that the eye turning round its axis pushes its way through the yielding bones from the blind to the upper side, others hold that, as soon as the body of the fish commences to rest on one side only, the eye of that side, in its tendency to turn towards the light, carries the surrounding parts of the head with it; in fact, the whole of the fore-part of the head is twisted towards the coloured side, which is a process of but little difficulty as long as the framework of the head is still cartilaginous.

Flat-fishes when adult live always on the bottom, and swim with an undulating motion of their body. Sometimes they rise to the surface; they prefer sandy bottom, and do not descend to any considerable depth. They occur in all seas, except in the highest latitudes and on rocky, precipitous coasts, becoming most numerous towards the equator; those of the largest size occur in the temperate zone. Some enter fresh water freely, and others have become entirely acclimatised in ponds and rivers. All are carnivorous.

Flat-fishes were not abundant in the tertiary epoch; the only representative known is a species of _Rhombus_ from Monte Bolca.

The size and abundance of Flat-fishes, and the flavour of the flesh of the majority of the species, render this family one of the most useful to man; and especially on the coasts of the northern temperate zone, their capture is one of the most important sources of profit to the fishermen.

PSETTODES.--Mouth very wide, the maxillary being more than
one-half of that of the head. Each jaw armed with two series of
long, slender, curved, distant teeth, the front teeth of the
inner series of the lower jaw being the longest, and received
in a groove before the vomer; vomerine and palatine teeth. The
dorsal fin commences on the nape of the neck.

This genus fitly heads the list of Flat-fishes, having retained more of symmetrical structure than the other members of the family, and, therefore, their eyes are as often found on the right as on the left side. It seems to swim, not unfrequently, in a vertical position. Only one species is known, _Ps. erumei_, common in the Indian Ocean.

HIPPOGLOSSUS.--Eyes on the right side; mouth wide, the length of
the maxillary being one-third of that of the head. Teeth in the
upper jaw in a double series; the anterior of the upper jaw and
the lateral of the lower strong. The dorsal fin commences above
the eye.

The “Holibut” (_H. vulgaris_) is the largest of all Flat-fishes, attaining to a length of five and six feet, and a weight of several hundredweights. It is found along the northern coasts of Europe, on the coasts of Kamtschatka and California, particularly frequenting banks situated at some distance from the coast, and at a depth of 50 to 120 fathoms.

Other genera, with nearly symmetrical mouth, in which the dorsal fin commences above the eye, are _Hippoglossoides_ (the “Rough Dab”) and _Tephritis_.

RHOMBUS.--Eyes on the left side. Mouth wide, the length of the
maxillary being more than one-third of that of the head. Each
jaw with a band of villiform teeth, without canines; vomerine
teeth, none on the palatines. The dorsal fin commences on the
snout. Scales none or small.

Seven species from the North Atlantic and Mediterranean, of which the most noteworthy are the “Turbot,” _Rh. maximus_, one of the most valued food-fishes, and growing to a length of three feet; the “Turbot of the Black Sea,” _Rh. mæoticus_, the body of which is covered with bony, conical tubercles, which are as large as the eye; the “Brill,” _Rh. lævis_, represented on the North American coasts by _Rh. aquosus_; the “Whiff,” or “Mary-sole,” or “Sail-fluke,” _Rh. megastoma_; “Bloch’s Top-knot,” _Rh. punctatus_ (described by Yarrell as _Rh. hirtus_, and often confounded with the following species).

PHRYNORHOMBUS, differing from _Rhombus_ in lacking vomerine teeth. The scales are very small and spiny.

The “Top-knot” (_Ph. unimaculatus_) occurs occasionally on the south coast of England, and is more common in the Mediterranean; it is a small species.

ARNOGLOSSUS.--Mouth wide, the length of the maxillary being
more or not much less than one-third of that of the head. Teeth
minute, in a single series in both jaws; vomerine or palatine
teeth none. The dorsal fin commences on the snout. Scales of
moderate size, deciduous; lateral line with a strong curve above
the pectoral. Eyes on the left side.

Seven species from European and Indian Seas. The “Scald-fish” (_A. laterna_) is common in the Mediterranean, and extends to the south coast of England; it is a small species.

PSEUDORHOMBUS.--Mouth wide, the length of the maxillary being
more than one-third of that of the head. Teeth in both jaws in a
single series, of unequal size; vomerine or palatine teeth none.
The dorsal fin commences on the snout. Scales small; lateral
line with a strong curve anteriorly. Eyes on the left side.
Interorbital space not concave.

A tropical genus with a few outlying species, represented chiefly in the Indo-Pacific, and also in the Atlantic. Seventeen species.

RHOMBOIDICHTHYS.--Mouth of moderate width or small. Teeth
minute, in a single or double series; vomerine or palatine teeth
none. Eyes separated by a concave more or less broad space. The
dorsal fin commences on the snout. Scales ciliated; lateral line
with a strong curve anteriorly. Eyes on the left side.

A tropical genus, but also represented in the Mediterranean and on the coast of Japan. Sixteen species, the majority of which are prettily coloured and ornamented with ocellated spots; in some species the adult males have some of the fin-rays prolonged into filaments.

Other genera with nearly symmetrical mouth, in which the dorsal fin commences before the eye, on the snout, are _Citharus_, _Anticitharus_, _Brachypleura_, _Samaris_, _Psettichthys_, _Citharichthys_, _Hemirhombus_, _Paralichthys_, _Liopsetta_, _Lophonectes_, _Lepidopsetta_, and _Thysanopsetta_.

PLEURONECTES.--Cleft of the mouth narrow, with the dentition
much more developed on the blind side than on the coloured.
Teeth in a single or in a double series, of moderate size;
palatine and vomerine teeth none. The dorsal fin commences above
the eye. Scales very small or entirely absent. Eyes generally on
the right side.

This genus is characteristic of the littoral fauna of the northern temperate zone, a few species ranging to the Arctic circle. Twenty-three species are known, of which the following are the most noteworthy: _P. platessa_, the “Plaice,” ranging from the coast of France to Iceland; _P. glacialis_, from the Arctic coasts of North America; _P. americanus_, the transatlantic representative of the Plaice; _P. limanda_, the common “Dab;” _P. microcephalus_, the “Smear-dab;” _P. cynoglossus_, the “Craig-fluke;” _P. flesus_, the “Flounder.”

RHOMBOSOLEA.--Eyes on the right side, the lower in advance of
the upper. Mouth narrower on the right side than on the left;
teeth on the blind side only, villiform; palatine and vomerine
teeth none. The dorsal fin commences on the foremost part of
the snout. Only one ventral which is continuous with the anal.
Scales very small, cycloid; lateral line straight.

This genus represents _Pleuronectes_ in the Southern Hemisphere, but consists of three species only, which occur on the coasts of New Zealand, and are valued as food-fishes.

Other genera, with narrow unsymmetrical mouth, in which the upper eye is not in advance of the lower, and which have pectoral fins, are _Parophrys_, _Psammodiscus_, _Ammotretis_, _Peltorhamphus_, _Nematops_, _Læops_, and _Poecilopsetta_.

SOLEA.--Eyes on the right side, the upper being more or less
in advance of the lower. Cleft of the mouth narrow, twisted
round to the left side. Villiform teeth on the blind side only;
vomerine or palatine teeth none. The dorsal fin commences on the
snout, and is not confluent with the caudal. Scales very small,
ctenoid; lateral line straight.

“Soles” are numerously represented in all suitable localities within the temperate and tropical zones, with the exception of the southern parts of the southern temperate zone, in which they are absent. Some enter or live in fresh water. Nearly forty species are known. British are _S. vulgaris_, the common “Sole;” _S. aurantiaca_, the “Lemon-sole,” which is rather a southern species, and inhabits, on the south coast of England, deeper water than the common Sole; _S. variegata_, the “Banded Sole,” with very small pectoral fins; and _S. minuta_, the “Dwarf-Sole.”--Allied to _Solea_ are _Pardachirus_ and _Liachirus_ from the Indian coasts.

SYNAPTURA.--Eyes on the right side, the upper in advance of
the lower. Cleft of the mouth narrow, twisted round to the
left side; minute teeth on the left side only. Vertical fins
confluent. Scales small, ctenoid; lateral line straight.

Twenty species; with the exception of two from the Mediterranean and coast of Portugal, all belong to the fauna of the Indian Ocean.--Closely allied is _Aesopia_.

GYMNACHIRUS.--Mouth very small, toothless. Scales none, lateral
line straight. Eyes on the right side. The dorsal fin commences
on the snout; caudal free. Pectorals rudimentary or entirely
absent.

Two species from the Tropical Atlantic.

CYNOGLOSSUS.--Eyes on the left side; pectorals none; vertical
fins confluent. Scales ctenoid; lateral line on the left side
double or triple; upper part of the snout produced backwards
into a hook; mouth unsymmetrical, rather narrow. Teeth minute,
on the right side only.

Abundant in the Indian seas, and especially on the flat sandy shores of China. About thirty-five species are known, which rarely exceed a length of eighteen inches. They are easily recognised by their long narrow shape (which has been compared to a dog’s tongue) and the peculiar form of their snout.

To complete the list of Pleuronectoid genera, the following
have to be mentioned: _Soleotalpa_ and _Apionichthys_, Soles
with rudimentary eyes; _Ammopleurops_, _Aphoristia_, and
_Plagusia_, which are closely allied to _Cynoglossus_, the
latter genus having the lips provided with tentacles.

FOURTH ORDER--PHYSOSTOMI.

_All the fin-rays articulated, only the first of the dorsal and pectoral fins is sometimes ossified. Ventral fins, if present, abdominal, without spine. Air-bladder, if present, with a pneumatic duct (except in Scombresocidæ)._

FIRST FAMILY--SILURIDÆ.

_Skin naked or with osseous scutes, but without scales. Barbels always present; maxillary bone rudimentary, almost always forming a support to a maxillary barbel. Margin of the upper jaw formed by the intermaxillaries only. Suboperculum absent. Air-bladder generally present, communicating with the organ of hearing by means of the auditory ossicles. Adipose fin present or absent._

A large family, represented by numerous genera, which exhibit a great variety of form and structure of the fins; they inhabit the fresh waters of all the temperate and tropical regions; a few enter the sea but keep near the coast. The first appearance of Siluroids is indicated by some fossil remains in tertiary deposits of the highlands of Padang in Sumatra, where _Pseudeutropius_ and _Bagarius_, types well represented in the living Indian fauna, have been found. Also in North America spines referable to Cat-fishes have been found in tertiary formations.

The skeleton of the typical Siluroids shows many peculiarities. The cranial cavity is not membranous on the sides, but closed as in the Cyprinidæ, by the orbitosphenoids and the ethmoid that unite with the prefrontals, carrying forward the cranial cavity to the nasal bone, without leaving a membranous septum between the orbits. But the supraoccipital is greatly developed, and in many the post-temporal is united by suture to the sides of the cranium. In numerous members of the family the skull is enlarged posteriorly, by dermal ossifications, to form a kind of helmet which spreads over the nape; the lateral angles of this production are formed by the suprascapulæ, augmented and fixed by suture, and the median part is the extension of the supraoccipital, which is generally very large, is connected anteriorly with the frontal, and passing backwards between the postfrontals, the parietals, the mastoids, and the suprascapulæ, goes past them all on to the nape. The mastoids interpose between the postfrontals and the parietals, so as to come in contact with the supraoccipital, and the parietals but little developed are pressed to the back part of the cranium, and in some instances wholly disappear.

The suprascapula most frequently unites to the mastoid by an immovable suture, which includes the parietal when that bone is present, and extends even to the supraoccipital. It gives out besides two processes, one of them resting on the exoccipital and basi-occipital, or wedging itself between them, and the other going to the first vertebra; sometimes a plate from the exoccipital supports the same vertebra. This vertebra, though it presents a pretty continuous centrum beneath, is in reality composed of three or four coalescent vertebræ, as we ascertain by its diapophyses, by the circular elevations of the neural canal, and by the holes for the exit of the pairs of spinal nerves. There is great variety in the development of the various processes of the bones we have mentioned, and there is no less in the magnitude and connections of the first three interneurals.

In general in the species which have a strong dorsal spine the second and third interneurals unite to form a single plate, the “buckler;” the great spine is articulated to the third interneural, and there is only the vestige of a spine on the second interneural in form of a small oval bone, forked below, whose function is to act as a bolt or fulcrum to the great spine when the fish wishes to use it as an offensive weapon. The great spine itself is joined by a ring to a second spine, which belongs to the third interneural. This articulation by ring exists in Lophius and a few other fishes not of this family.

The first interneural does not carry a ray, and it varies much in the species whose helmet is continuous with the buckler, as in many of the Bagri and Pimelodi. In these cases the supraoccipital, extending backwards, conceals the first interneural, passing over it to touch with its point the buckler formed by the second and third interneurals. In other instances, as in Synodontis and Auchenipterus, the supraoccipital and second interneural, forking and expanding, inclose and join themselves to the first interneural, but leave a larger or smaller space in the middle of the nuchal armour which they contribute to form. When the point of the supraoccipital does not reach quite to the second interneural, the first interneural remains free from connection, and occasionally shows as a narrow plate interposed between the other two; in such a case the helmet is not continuous with the buckler.

The neural spines of the coalescent centra, which form the apparently single first vertebra, concur also in sustaining the nuchal plate-armour and the first great dorsal spine. They carry the interneurals, are joined to them by suture, and one of them is often inclined towards the occiput to assist in sustaining the head; in fact, this part of the skeleton is constructed to give firm mutual support.

The shoulder-girdle of the Siluroids is also formed to give resistance to the strong weapon with which it is frequently armed. The post-temporal, as we have said above, is often united by suture to the cranium, and it obtains support below by one or two processes that are fixed on the basioccipitals and on the diapophysis of the first vertebra.

In most osseous fishes the clavicle completes the lower key of the scapular arch in joining its fellow by suture or synchondrosis without the intervention of the coracoid; but in the Siluroids the coracoid descends to take part in this joint, and sometimes even to occupy the half of the suture, which is not unfrequently constructed of very deep interlocking serratures. The solidity of this base of the pectoral spine is further augmented by the intimate union of the coracoid and scapula, which often extends to junction by suture, or even to coalescence; and these bones, moreover, give off two bony arches--the first a slender one, arising from the salient edge of the coracoid near the pectoral fin, and going to the interior face of the scapular that is applied to the interior surface of the ascending branch of the clavicle; the second and broader supplementary arch is often perforated by a large hole; it also emanates from the same salient edge of the radius, but proceeds in opposite direction to the inferior edge of the clavicle, a little before the insertion of the pectoral spine. The two arches give attachments to the muscles that move this spine; in the Synodontes and many Bagri the upper arch remains in a cartilaginous or ligamentous condition, while in Malapterurus it is the lower arch that does not ossify, but both are fully formed in the Siluri and many other Siluroids more closely allied to that typical genus. The postclavicle is also wanting in the Siluroids. The pterygoid and entopterygoid are reduced to a single bone, the symplectic is wholly wanting, and the palatine is merely a slender cylindrical bone. The sub-operculum is likewise constantly absent in all the Siluroids.

The great number of different generic types has necessitated a further division of this family into eight subdivisions:

I. SILURIDÆ HOMALOPTERÆ.--_The dorsal and anal fins are very long, nearly equal in extent to the corresponding parts of the vertebral column._

_a_. CLARIINA.

CLARIAS.--Dorsal fin extending from the neck to the caudal,
without adipose division. Cleft of the mouth transverse,
anterior, of moderate width; barbels eight; one pair of nasal,
one of maxillary, and two pairs of mandibulary barbels. Eyes
small. Head depressed; its upper and lateral parts are osseous,
or covered with only a very thin skin. A dendritic accessory
branchial organ is attached to the convex side of the second and
fourth branchial arches, and received in a cavity behind the
gill-cavity proper. Ventrals six-rayed; only the pectoral has a
pungent spine. Body eel-like.

Twenty species from Africa, the East Indies, and the intermediate parts of Asia; some attain to a length of six feet. They inhabit muddy and marshy waters; the physiological function of the accessory branchial organ is not known. Its skeleton is formed by a soft cartilaginous substance covered by mucous membrane, in which the vessels are imbedded. The vessels arise from branchial arteries, and return the blood into branchial veins. The vernacular name of the Nilotic species is “Carmoot.”

HETEROBRANCHUS differs from _Clarias_ only in the structure of
the dorsal fin, the posterior portion of which is adipose.

The geographical range of this genus is not quite co-extensive with that of _Clarias_, inasmuch as it is limited to Africa and the East-Indian Archipelago. Six species.

_b_. PLOTOSINA.

PLOTOSUS.--A short dorsal fin in front, with a pungent spine; a
second long dorsal coalesces with the caudal and anal. Vomerine
teeth molar-like. Barbels eight or ten; one immediately before
the posterior nostril, which is remote from the anterior, the
latter being quite in front of the snout. Cleft of the mouth
transverse. Eyes small. The gill-membranes are not confluent
with the skin of the isthmus. Ventral fins many-rayed. Head
depressed; body elongate.

Three species are known from brackish waters of the Indian Ocean freely entering the sea. _Plotosus anguillaris_ is distinguished by two white longitudinal bands, and is one of the most generally distributed and common Indian fishes.--_Copidoglanis_ and _Cnidoglanis_ are two very closely allied forms, chiefly from rivers and brackish waters of Australia. None of these Siluroids attain to a considerable size. _Chaca_, from the East Indies, belongs likewise to this sub-family.

II. SILURIDÆ HETEROPTERÆ.--_The rayed dorsal fin is very little developed, and, if it is present, it belongs to the abdominal portion of the vertebral column; the adipose fin is exceedingly small or absent. The extent of the anal is not much inferior to that of the caudal vertebral column. The gill-membranes overlap the isthmus, remaining more or less separate_: SILURINA.

SACCOBRANCHUS.--Adipose fin none; dorsal very short, without
pungent spine, placed above the ventrals. Cleft of the mouth
transverse, anterior, of moderate width; barbels eight. Eyes
rather small. The upper and lateral parts of the head osseous
or covered with a very thin skin. Gill-cavity with an accessory
posterior sac, extending backwards between the muscles along
each side of the abdominal and caudal portions of the vertebral
column. Ventrals six-rayed.

Small fishes from East Indian rivers; four species are known. The lung-like extension of the branchial cavity receives water, and is surrounded by contractile transverse muscular fibres by which the water is expelled at intervals. The vessels of the sac take their origin in the last branchial artery, and pass into the aorta.

SILURUS.--No adipose fin; one very short dorsal, without pungent
spine. Barbels four or six, one to each maxillary, and one or
two to each mandible. Nostrils remote from each other. Head
and body covered with soft skin. The eye is situated above the
level of the angle of the mouth. The dorsal fin is anterior to
the ventrals which are composed of more than eight rays. Caudal
rounded.

This genus, of which five species are known, inhabits the temperate parts of Europe and Asia. The species which has given the name to the whole family, is the “Wels” of the Germans, _Silurus glanis_. It is found in the fresh waters east of the Rhine, and is, besides the Sturgeons, the largest of European Freshwater-fishes, and the only species of this family which occurs in Europe. Barbels six. It attains to a weight of 300 or 400 lbs., and the flesh, especially of smaller specimens, is firm, flaky, and well flavoured. Aristotle described it under the name of _Glanis_. Its former occurrence in Scotland has justly been denied. In China it is represented by a similar species, _S. asotus_, which, however, has four barbels only.

This sub-family is well represented by various other genera in the fresh waters of the African as well as Indian region. African genera are _Schilbe_ and _Eutropius_; East Indian: _Silurichthys_, _Wallago_, _Belodontichthys_, _Eutropiichthys_, _Cryptopterus_, _Callichrous_, _Hemisilurus_, _Siluranodon_, _Ailia_, _Schilbichthys_, _Lais_, _Pseudeutropius_, _Pangasius_, _Helicophagus_, and _Silondia_.

III. SILURIDÆ ANOMALOPTERÆ.--_Dorsal and adipose fins very short, the former belonging to the caudal vertebral column; anal very long. Ventrals in front of the dorsal. Gill-membranes entirely separate, overlapping the isthmus_: (HYPOPHTHALMINA.)

HYPOPHTHALMUS.--Dorsal fin with seven rays, the first of which
is slightly spinous. The lower jaw is rather the longer. Barbels
six, those of the mandible long. No teeth; intermaxillaries very
feeble. Head covered with skin. Eye of moderate size, situated
behind and below the angle of the mouth. Ventrals small,
six-rayed.

Four species from tropical America. The second genus of this sub-family is _Helogenes_ from the Essequibo.

IV. SILURIDÆ PROTEROPTERÆ.--_The rayed dorsal fin is always present, short, with not more than twelve short rays, and belongs to the abdominal portion of the vertebral column, being placed in advance of the ventrals. The adipose fin is always present and well developed, although frequently short. The extent of the anal is much inferior to that of the caudal vertebral column. The gill-membranes are not confluent with the skin of the isthmus, their posterior margin always remaining free even if they are united with each other. Whenever the nasal barbel is present it belongs to the posterior nostril._

_a._ BAGRINA.

BAGRUS.--Adipose fin long; a short dorsal with a pungent spine
and nine or ten soft rays; anal fin short, with less than twenty
rays. Barbels eight. The anterior and posterior nostrils are
remote from each other, the posterior being provided with a
barbel. Teeth on the palate in a continuous band. Eyes with a
free orbital margin. Caudal forked; ventrals six-rayed.

This genus consists of two species only, common in the Nile, viz. the “Bayad,” _B. bayad_, and _B. docmac_. Both grow to a large size, exceeding a length of five feet, and are eaten. _Chrysichthys_ and _Clarotes_ are two other Siluroid genera from African rivers, closely allied to Bagrus. Similar Siluroids are common in the East Indies, and have been referred to the following genera: _Macrones_, _Pseudobagrus_, _Liocassis_, _Bagroides_, _Bagrichthys_, _Rita_, _Acrochordonichthys_, _Akysis_.

_b._ AMIURINA.

AMIURUS.--Adipose fin of moderate length; a short dorsal with a
pungent spine and six soft rays; anal fin of moderate length.
Barbels eight. The anterior and posterior nostrils are remote
from each other, the posterior being provided with a barbel.
Palate edentulous. Head covered with skin above. Ventrals
eight-rayed.

The “Cat-fishes” of North America, of which about a dozen different species are known. One species occurs in China. Allied, but smaller forms are _Hopladelus_ and _Noturus_, likewise from North America.

_c_. PIMELODINA.

PLATYSTOMA.--Adipose fin of moderate length; a short dorsal fin
with a pungent spine and six or seven soft rays; anal fin rather
short. Snout very long, spatulate, with the upper jaw more or
less projecting; the upper surface of the head not covered by
the skin. Barbels six; the anterior and posterior nostrils
remote from each other, none with a barbel. Palate toothed.
Caudal forked; ventrals six-rayed, inserted behind the dorsal.

Twelve species from South America, some attaining a length of six feet, the majority being ornamented with deep-black spots or bands. Allied genera from South America, likewise distinguished by a long spatulate snout, are _Sorubim_, _Hemisorubim_, and _Platystomatichthys_, whilst _Phractocephalus_, _Piramutana_, _Platynematichthys_, _Piratinga_, _Bagropsis_, and _Sciades_, have a snout of ordinary length. The barbels of some are of extraordinary length, and not rarely dilated and band-like.

PIMELODUS.--Adipose fin well developed; dorsal fin short, with a
more or less pungent spine and six rays; anal fin short. Barbels
six, cylindrical or slightly compressed, none of them belonging
to either of the nostrils, which are remote from each other.
Palate edentulous. Ventrals six-rayed, inserted behind the
dorsal.

Of all South American genera this is represented by the greatest number of species, more than forty being well characterised; they differ chiefly with regard to the length of the adipose fin and barbels, and the strength of the dorsal spine. Singularly, two species (_P. platychir_ and _P. balayi_), are found in West Africa. The majority are of but moderate size and plain coloration.--Allied South American genera (also without teeth on the palate), are _Pirinampus_, _Conorhynchus_, _Notoglanis_, _Callophysus_, _Lophiosilurus_.

AUCHENOGLANIS.--Adipose fin rather long, dorsal short, with
a pungent spine and seven rays; anal short. Snout produced,
pointed, with narrow mouth. Barbels six, none of which belongs
to either of the nostrils, which are remote from each other. The
teeth of each jaw form a pair of small elliptic patches which
are longer than broad; palate edentulous. Eyes of moderate size.
Ventrals six-rayed.

One species, _Au. biscutatus_, from the Nile, Senegal, and other West African rivers.

_d._ ARIINA.

ARIUS.--Adipose fin of moderate length or short; a short dorsal
fin with a pungent spine and seven soft rays; anal fin rather
short. Head osseous above; barbels six, four at the mandible,
none at either of the nostrils which are close together.
Eyes with a free orbital margin. Caudal fin forked; ventrals
six-rayed, behind the dorsal.

Of all Siluroid genera this has the greatest number of species (about seventy), and the widest distribution, being represented in almost all tropical countries which are drained by large rivers; some of the species prefer brackish to fresh water, and a few enter the sea, but keep near to the coast. Some of the species are of small size, whilst others exceed a length of five feet. The extent of the armature of the neck and the dentition vary much in the different species, and affords two of the principal characters by which the species are separated.--The following genera are allied to _Arius_, _Galeichthys_ from South Africa; _Genidens_ and _Paradiplomystax_ from Brazil; _Diplomystax_ from Chile; _Aelurichthys_ from Central and South America; _Hemipimelodus_, _Ketengus_, _Osteo__geniosus_, and _Batrachocephalus_ from the East Indies; and _Atopochilus_ from West Africa.

_e._ BAGARIINA.

BAGARIUS.--Adipose fin rather short; a short dorsal with one
spine and six rays; anal fin of moderate length. Barbels eight,
of which one pair stands between the anterior and posterior
nostrils which are close together. Head naked above. Caudal fin
deeply forked; ventrals rays six. Thorax without longitudinal
plaits of the skin.

A large Siluroid (_B. bagarius_) from rivers of India and Java; exceeding a length of six feet.

EUGLYPTOSTERNUM.--Adipose fin of moderate length; a short
dorsal with a pungent spine and six rays; anal fin short.
Barbels eight, of which one pair is placed between the anterior
and posterior nostrils which are close together. Teeth on the
palate villiform, in two separate patches. Eyes small, below the
skin. Caudal forked; ventral rays six. Pectorals horizontal,
with a thoracic adhesive apparatus between, which is formed by
longitudinal plaits of the skin.

This fish (_Eu. coum_) inhabits the river Coic in Syria, and is about twelve inches long. The plaited structure on the thorax probably increases the capability of the fish of maintaining its position in the rapid current of the stream, a function which appears to be chiefly performed by the horizontally expanded pectoral fins. A similar structure is found in _Glyptosternum_, a genus represented by eight species in mountain streams of the East Indies, and differing from the Syrian species in lacking the teeth on the palate.

V. SILURIDÆ STENOBRANCHIÆ.--_The rayed dorsal fin is short, if present, belonging to the abdominal portion of the vertebral column, the ventrals being inserted behind it (except in Rhinoglanis). The gill-membranes are confluent with the skin of the isthmus._

_a_. DORADINA.

Some of the genera have no bony shields along the lateral line, and a small adipose fin or none whatever; all of these are South American--_Ageniosus_, _Tetranematichthys_, _Euanemus_, _Auchenipterus_, _Glanidium_, _Centromochlus_, _Trachelyopterus_, _Cetopsis_, and _Astrophysus_.

Others have a series of bony scutes along the middle of the side; they form the genus _Doras_ with two closely allied forms, _Oxydoras_ and _Rhinodoras_. Some twenty-five species are known, all from rivers of tropical America, flowing into the Atlantic. These fishes have excited attention by their habit of travelling, during the dry season, from a piece of water about to dry up, in quest of a pond of greater capacity. These journeys are occasionally of such a length that the fish spends whole nights on the way, and the bands of scaly travellers are sometimes so large that the Indians who happen to meet them, fill many baskets of the prey thus placed in their hands. The Indians supposed that the fish carry a supply of water with them, but they have no special organs, and can only do so by closing the gill-openings, or by retaining a little water between the plates of their bodies, as Hancock supposes. The same naturalist adds that they make regular nests, in which they cover up their eggs with care and defend them, male and female uniting in this parental duty until the eggs are hatched. The nest is constructed at the beginning of the rainy season, of leaves, and is sometimes placed in a hole scooped out in the beach.

Finally, in the last genus, the lateral scutes are likewise absent, viz. in

SYNODONTIS.--The adipose fin is of moderate length or rather
long; the dorsal fin has a very strong spine and seven soft
rays. The teeth in the lower jaw are movable, long, very thin
at the base, and with a slightly-dilated brown apex. Mouth
small. Barbels six, more or less fringed with a membrane or with
filaments. Neck with broad dermal bones.

Synodontis is characteristic of the fauna of tropical Africa, where it is represented by fifteen species. Several occur in the Nile, and are known by the vernacular name “Schal.” Some attain a length of two feet. The species figured is from West Africa, and characterised by its long upper jaw.

_b_. RHINOGLANINA.

RHINOGLANIS.--Two dorsal fins, both composed of rays, the first
with a strong spine; anal rather short. Barbels six; anterior
and posterior nostrils close together, the posterior very large,
open. Neck with broad dermal bones. Ventrals with seven rays,
inserted below the posterior rays of the first dorsal fin.

This Siluroid is known from a single example only one and a
half inches long, obtained at Gondokoro on the Upper Nile.
_Callomystax_ represents this type in the Ganges and Indus.

_c_. MALAPTERURINA.

MALAPTERURUS.--One dorsal fin only, which is adipose and
situated before the caudal; anal of moderate length or short;
caudal rounded; ventrals six-rayed, inserted somewhat behind the
middle of the body; pectorals without pungent spine. Barbels
six: one to each maxillary and two on each side of the mandible.
The anterior and posterior nostrils are remote from each other.
No teeth on the palate. The entire head and body covered with
soft skin. Eyes small. Gill-opening very narrow, reduced to a
slit before the pectoral.

The “Electric Cat- or Sheath-fishes” are not uncommon in the fresh waters of tropical Africa; three species have been described, of which _M. electricus_ occurs in the Nile; they grow to a length of about four feet. Although the first dorsal fin is absent, its position (if it had been developed) is indicated by a rudimentary interneural spine, which rests in the cleft of the neural process of the first vertebra. The electric organ extends over the whole body, but is thickest on the abdomen; it lies between two aponeurotic membranes, below the skin, and consists of rhomboidal cells which contain a rather firm gelatinous substance. The electric nerve takes its origin from the spinal chord, does not enter into connection with ganglia, and consists of a single enormously-strong primitive fibre, which distributes its branches in the electric organ.

VI. SILURIDÆ PROTEROPODES.--_The rayed dorsal fin is always present and rather short; the ventrals are inserted below (very rarely in front of) the dorsal. The gill-membranes are confluent with the skin of the isthmus, the gill-opening being reduced to a short slit. Pectorals and ventrals horizontal. Vent before, or not much behind, the middle of the length of the body._

_a_. HYPOSTOMATINA.

STYGOGENES.--Adipose fin short; dorsal and anal short; the outer
fin-rays somewhat thickened and rough; palate toothless; cleft
of the mouth of moderate width, with a maxillary barbel on each
side; a short broad flap on each side between the nostrils,
which are close together. Lower lip very broad, pendent. Eyes
small, covered with transparent skin. Head covered with soft
skin. Ventrals six-rayed.

These small Siluroids, which are called “Preñadillas” by the natives, together with the allied _Arges_, _Brontes_, and _Astroplebus_, have received some notoriety through Humboldt’s accounts, who adopted the popular belief that they live in subterranean waters within the bowels of the active volcanoes of the Andes, and are ejected with streams of mud and water during eruptions. Humboldt himself considers it very singular that they are not cooked and destroyed whilst they are vomited forth from craters or other openings. The explanation of their appearance during volcanic eruptions is, that they abound in the numerous lakes and torrents of the Andes, that they are killed by the sulphuretted gases escaping during an eruption, and swept down by the torrents of water issuing from the volcano.

CALLICHTHYS.--Adipose fin short, supported anteriorly by a short
movable spine; dorsal with a feeble spine and seven or eight
rays; anal short. Teeth minute or entirely absent; cleft of the
mouth rather narrow, with a pair of maxillary barbels on each
side, which are united at the base. Eyes small. Head covered
with osseous plates; body wholly protected by two series of
large imbricate shields on each side. Ventrals six-rayed.

Twelve species of this genus are known; they are small, and similarly distributed as _Doras_, with which they have much in common as regards their mode of life. They likewise are able to travel over land, and construct nests for their ova.

CHÆTOSTOMUS.--A short adipose fin, supported anteriorly by a
short, compressed, curved spine; dorsal fin of moderate length,
with from eight to ten rays, the first of which is simple; anal
fin short; ventral six-rayed; pectoral with a strong spine. Head
and body completely cuirassed, the lower parts being sometimes
naked; body rather short, with four or five longitudinal series
of large imbricate scutes on each side; tail not depressed.
Snout produced, obtuse in front; mouth inferior, transverse,
with a single series of generally very fine bent teeth in both
jaws. Interoperculum very movable and armed with erectile spines.

This genus, with the allied _Plecostomus_, _Liposarcus_,
_Pterygoplichthys_, _Rhinelepis_, _Acanthicus_, and
_Xenomystus_, is well represented in the fresh waters of South
America, whence about sixty species are known. The majority
do not exceed a length of twelve inches, but some attain to
more than double that size. In some of the species the male is
provided with long bristles round the margin of the snout and
interoperculum.

_Hypoptopoma._--Differing from _Chætostomus_ in the peculiar
formation of the head, which is depressed, spatulate, the eyes
being on the lateral edge of the head. The movable gill-covers
are reduced to two bones, neither of which is armed, viz.--the
operculum small and placed as in _Chætostomus_, and a second,
larger one, separated from the eye by the narrow sub-orbital
ring, and placed at the lower side of the head.

LORICARIA.--One short dorsal fin; anal short; the outer ray
of each fin thickened, but flexible. Head depressed, with the
snout more or less produced and spatulate. Mouth situated at the
lower side of the snout, remote from its extremity, transverse,
surrounded by broad labial folds which are sometimes fringed;
a short barbel at each corner of the mouth. Teeth in the jaws
small, bent, with a dilated, notched apex, in a single series,
sometimes absent. Head and body cuirassed; tail depressed, long;
eye rather small or of moderate size.

Small fishes from rivers of tropical America; about twenty-six species are known. The male of some species has a bearded or bristly snout.

ACESTRA differs from _Loricaria_ in having the snout much
prolonged.

SISOR.--Head depressed, spatulate; trunk depressed; tail
long and thin. One short dorsal fin; anal short; ventrals
seven-rayed. Head partially osseous, rough; a series of bony
plates along the median line of the back; lateral line rough.
Eyes very small. Mouth inferior, small, transverse, with
barbels; teeth none.

A single species, _S. rhabdophorus_, from rivers of northern Bengal. Allied to this genus is _Erethistes_ from Assam.

PSEUDECHENEIS.--Adipose fin of moderate length; a short dorsal
with one spine and six rays; anal fin rather short. Barbels
eight. Mouth small, inferior. Head depressed, covered with soft
skin above; eyes small, superior. Caudal fin forked; pectorals
horizontal, with a thoracic adhesive apparatus between, formed
by transverse plaits of the skin. Ventrals six-rayed.

A very small species, inhabiting the mountain-streams of Khassya; by means of the adhesive apparatus it is enabled to hold on to stones, thus preventing the current from sweeping it away. _Exostoma_ is a similar small Siluroid from Indian mountain-streams, but without the thoracic apparatus; probably its mouth performs the same function.

_b_. ASPREDININA.

ASPREDO.--Adipose fin none; dorsal short, without pungent spine;
anal very long, but not united with the caudal. Head broad,
much depressed; tail very long and slender. Barbels not less
than six, one of which is attached to each intermaxillary; none
at the nostrils. Eyes very small. Head covered with soft skin;
the anterior and posterior nostrils are remote from each other.
Ventrals six-rayed.

Six species are known from Guyana; the largest grows to a length of about eighteen inches. The remarkable mode of taking care of their ova has been noticed above (p. 161, Fig. 72). _Bunocephalus_, _Bunocephalichthys_, and _Harttia_, from tropical America, are other genera of this sub-family which remain to be mentioned.

VII. SILURIDÆ OPISTHOPTERÆ.--_The rayed dorsal fin is always present, short, and placed above or behind the middle of the length of the body, above or behind the ventrals which, however, are sometimes absent; anal short. Nostrils remote from each other; if a nasal barbel is present, it belongs to the anterior nostril. Lower lip not reverted. The gill-membranes are not confluent with the skin of the isthmus_: NEMATOGENYINA and TRICHOMYCTERINA.

The genera _Heptapterus_, _Nematogenys_, _Trichomycterus_, _Eremophilus_, and _Pariodon_, belong to this sub-family. They are small South American Siluroids, the majority of which inhabit waters at high altitudes, up to 14,000 feet above the level of the sea. In the Andes they replace the Loaches of the Northern Hemisphere, which they resemble in appearance and habits, and even in coloration, offering a striking example of the fact that similar forms of animals are produced under similar external physical conditions.

VIII. SILURIDÆ BRANCHICOLÆ.--_The rayed dorsal fin is present, short, and placed behind the ventrals; anal short. Vent far behind the middle of the length of the body. Gill-membranes confluent with the skin of the isthmus._

_Stegophilus_ and _Vandellia_, two genera from South America, comprising the smallest and least developed Siluroids. Their body is narrow, cylindrical, and elongate; a small barbel at each maxillary; the operculum and interoperculum are armed with short stiff spines. The natives of Brazil accuse these fishes of entering and ascending the urethra of persons while bathing, causing inflammation and sometimes death. This requires confirmation, but there is no doubt that they live parasitically in the gill-cavity of larger fishes (_Platystoma_), but probably they enter these cavities only for places of safety, without drawing any nourishment from their host.

SECOND FAMILY--SCOPELIDÆ.

_Body naked or scaly. Margin of the upper jaw formed by the intermaxillary only; opercular apparatus sometimes incompletely developed. Barbels none. Gill-opening very wide; pseudobranchiæ well developed. Air-bladder none. Adipose fin present. The eggs are enclosed in the sacs of the ovary, and excluded by oviducts. Pyloric appendages few in number or absent. Intestinal tract very short._

Exclusively marine, the majority being either pelagic or deep-sea forms. Of fossil remains the following have been referred to this family:--_Osmeroides_, from Mount Lebanon, which others believe to be a marine salmonoid; _Hemisaurida_, from Comen, allied to _Saurus_; _Parascopelus_ and _Anapterus_, from the miocene of Licata, the latter genus allied to _Paralepis_.

SAURUS (inclus. _Saurida_).--Body sub-cylindrical, rather
elongate, covered with scales of moderate size; head oblong;
cleft of the mouth very wide; intermaxillary very long,
styliform, tapering; maxillary thin, long, closely adherent
to the intermaxillary. Teeth card-like, some being elongate,
slender; all can be laid downwards and inwards. Teeth on the
tongue, and palatine bones. Eye of moderate size. Pectorals
short; ventrals eight- or nine-rayed, inserted in advance of the
dorsal, not far behind the pectorals. Dorsal fin nearly in the
middle of the length of the body, with thirteen or less rays;
adipose fin small; anal short or of moderate length; caudal
forked.

Fifteen species of small size, from the shores of the tropical and sub-tropical zones. The species figured on p. 42, Fig. 5, occurs on the north-west coast of Australia and in Japan.

BATHYSAURUS.--Shape of the body similar to that of _Saurus_,
sub-cylindrical, elongate, covered with small scales. Head
depressed, with the snout produced, flat above. Cleft of the
mouth very wide, with the lower jaw projecting; intermaxillary
very long, styliform, tapering, not movable. Teeth in the jaws,
in broad bands, not covered by lips, curved, unequal in size
and barbed at the end. A series of similar teeth runs along the
whole length of each side of the palate. Eye of moderate size,
lateral. Pectoral of moderate length. Ventral eight-rayed,
inserted immediately behind the pectoral. Dorsal fin in the
middle of the length of the body, with about eighteen rays.
Adipose fin absent or present. Anal of moderate length. Caudal
emarginate.

Deep-sea fishes, obtained in the Pacific at depths varying from 1100 to 2400 fathoms. The largest example is twenty inches long. Two species.

BATHYPTEROIS.--Shape of the body like that of an _Aulopus_. Head
of moderate size, depressed in front, with the snout projecting,
the large mandible very prominent beyond the upper jaw. Cleft
of the mouth wide; maxillary developed, very movable, much
dilated behind. Teeth in narrow villiform bands in the jaws. On
each side of the broad vomer a small patch of similar teeth;
none on the palatines or on the tongue. Eye very small. Scales
cycloid, adherent, of moderate size. Rays of the pectoral fin
much elongated, some of the upper being separate from the rest,
and forming a distinct division. Ventrals abdominal, with the
outer rays prolonged, eight-rayed. Dorsal fin inserted in the
middle of the body, above or immediately behind the root of the
ventral, of moderate length. Adipose fin present or absent. Anal
short. Caudal forked.

This very singular form is one of the discoveries of the “Challenger;” it is widely distributed over the seas of the Southern Hemisphere, in depths varying from 520 to 2600 fathoms. The elongate pectoral rays are most probably organs of touch. Four species were discovered, the largest specimen being thirteen inches long.

HARPODON.--Body elongate, covered with very thin, diaphanous,
deciduous scales. Head thick, with very short snout; its bones
are very soft, and the superficial ones are modified into wide
muciferous cavities; the lateral canal of the body is also
very wide, and a pair of pores corresponds to each scale of the
lateral line, one being above, the other below the scale. Cleft
of the mouth very wide; intermaxillary very long, styliform,
tapering; maxillary absent. Teeth card-like, recurved, unequal
in size; the largest are in the lower jaw, and provided with a
single barb at the posterior margin of the point. Eye small.
Ventral fins long, nine-rayed, inserted below the anterior
dorsal rays; dorsal fin in the middle of the length of the
body; adipose fin small; anal of moderate length; caudal fin
three-lobed, the lateral line being continued along the central
lobe. Centre of the vertebræ open in the middle.

Two species only are known of this singular genus; both are evidently inhabitants of considerable depths, and periodically come nearer to the surface. One (_H. nehereus_) is well known in the East Indies, being of excellent flavour. When newly taken its body is brilliantly phosphorescent. When salted and dry it is known under the names of “Bombay-ducks” or “Bummaloh,” and exported in large quantities from Bombay and the coast of Malabar. The second species (_H. microchir_) exceeds the other in length, and has been found in the sea off Japan.

SCOPELUS.--Body oblong, more or less compressed, covered with
large scales. Series of phosphorescent spots run along the lower
side of the body, and a similar glandular substance sometimes
occupies the front of the snout and the back of the tail. Cleft
of the mouth very wide. Intermaxillary very long, styliform,
tapering; maxillary well developed. Teeth villiform. Eye large.
Ventrals eight-rayed, inserted immediately in front of or below
the anterior dorsal rays. Dorsal fin nearly in the middle of
the length of the body; adipose fin small; anal generally long;
caudal forked. Branchiostegals from eight to ten.

The fishes of this genus are small, of truly pelagic habits, and distributed over all the temperate and tropical seas; they are so numerous that the surface-net, when used during a night of moderate weather, scarcely ever fails to enclose some specimens. They come to the surface at night only; during the day and in very rough weather they descend to depths where they are safe from sunlight or the agitation of the water. Some species never rise to the surface; indeed, Scopeli have been brought up in the dredge from almost any depth to 2500 fathoms. Thirty species are known. _Gymnoscopelus_ differs from _Scopelus_ in lacking scales.

IPNOPS.--Body elongate, sub-cylindrical, covered with large,
thin, deciduous scales, and without phosphorescent organs. Head
depressed, with broad, long, spatulate snout, the whole upper
surface of which is occupied by a most peculiar organ of vision
(or luminosity), longitudinally divided in two symmetrical
halves. Bones of the head well ossified. Mouth wide, with the
lower jaw projecting; maxillary dilated behind. Both jaws with
narrow bands of villiform teeth; palate toothless. Pectoral and
ventral fins well developed, and, owing to the shortness of the
trunk, close together. Dorsal fin at a short distance behind
the vent; adipose fin none; anal fin moderately long; caudal
subtruncated. Pseudobranchiæ none.

This singular genus, one of the “Challenger” discoveries, is known from four examples, obtained at depths varying between 1600 and 2150 fathoms, off the coast of Brazil, near Tristan d’Acunha and north of Celebes. All belong to one species, _I. murrayi_. The eye seems to have lost its function of vision and assumed that of producing light. The specimens are from 4 to 5½ inches long.

PARALEPIS.--Head and body elongate, compressed, covered with
deciduous scales. Cleft of the mouth very wide; maxillary
developed, closely adherent to the intermaxillary. Teeth in
a single series, unequal in size. Eye large. Ventrals small,
inserted opposite or nearly opposite the dorsal. Dorsal fin
short, on the hinder part of the body; adipose fin small; anal
elongate, occupying the end of the tail; caudal emarginate.

Three species; small pelagic fishes from the Mediterranean and Atlantic.--_Sudis_, from the Mediterranean, has a dentition slightly different from that of _Paralepis_.