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.

[Illustration: Fig. 269.--Scopelus boops.]

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_.

Plagyodus.--Body elongate, compressed, scaleless; snout much

produced, with very wide cleft of the mouth. Intermaxillary very

long and slender; maxillary thin, immovable. Teeth in the jaws

and of the palate very unequal in size, the majority pointed

and sharp, some very large and lanceolate. Eye large. Pectoral

and ventral fins well developed; the rayed dorsal fin occupies

the whole length of the back from the occiput to opposite the

anal fin; adipose and anal fins of moderate size. Caudal forked.

Branchiostegals six or seven.

[Illustration: Fig. 270.--Plagyodus ferox.]

This is one of the largest and most formidable deep-sea fishes. One

species only is well known, _P. ferox_, from Madeira and the sea

off Tasmania; other species have been noticed from Cuba and the

North Pacific, but it is not evident in what respects they differ

specifically from _P. ferox_. This fish grows to a length of six feet,

and from the stomach of one example have been taken several Octopods,

Crustaceans, Ascidians, a young Brama, twelve young Boar-fishes,

a Horse-mackerel, and one young of its own species. The stomach is

coecal; the commencement of the intestine has extremely thick walls,

its inner surface being cellular, like the lung of a reptile; a

pyloric appendage is absent. All the bones are extremely thin, light,

and flexible, containing very little earthy matter; singular is the

development of a system of abdominal ribs, symmetrically arranged on

both sides, and extending the whole length of the abdomen. Perfect

specimens are rarely obtained on account of the want of coherence of

the muscular and osseous parts, caused by the diminution of pressure

when the fish reaches the surface of the water. The exact depth at

which _Plagyodus_ lives is not known; probably it never rises above a

depth of 300 fathoms.

The other less important genera belonging to this family are _Aulopus_,

_Chlorophthalmus_, _Scopelosaurus_, _Odontostomus_, and _Nannobrachium_.

[Illustration: Fig. 271.--Pharyngeal bones and teeth of the

Bream, Abramis brama.]

THIRD FAMILY--CYPRINIDÆ.

_Body generally covered with scales; head naked. Margin of the upper

jaw formed by the intermaxillaries. Belly rounded, or, if trenchant,

without ossifications. No adipose fin. Stomach without blind sac.

Pyloric appendages none. Mouth toothless; lower pharyngeal bones

well developed, falciform, sub-parallel to the branchial arches,

provided with teeth, which are arranged in one, two, or three series.

Air-bladder large, divided into an anterior and posterior portion by a

constriction, or into a right or left portion, enclosed in an osseous

capsule. Ovarian sacs closed._

The family of “Carps” is the one most numerously represented in the

fresh waters of the Old World and of North America. Also numerous

fossil remains are found in tertiary freshwater-formations, as in the

limestones of Oeningen and Steinheim, in the lignites of Bonn, Stöchen,

Bilin, and Ménat, in the marl slates and carbonaceous shales of

Licata in Sicily, and of Padang in Sumatra, in corresponding deposits

of Idaho in North America. The majority can be referred to existing

genera: _Barbus_, _Thynnichthys_, _Gobio_, _Leuciscus_, _Tinca_,

_Amblypharyngodon_, _Rhodeus_, _Cobitis_, _Acanthopsis_, only a few

showing characters different from those of living genera: _Cyclurus_,

_Hexapsephus_, _Mylocyprinus_ (tertiary of North America).

Most Carps feed on vegetable and animal substances; a few only are

exclusive vegetable feeders. There is much less diversity of form and

habits in this family than in the Siluroids; however, the genera are

sufficiently numerous to demand a further subdivision of the family

into groups.

I. CATOSTOMINA.--_Pharyngeal teeth in a single series, exceedingly

numerous and closely set. Dorsal fin elongate, opposite to the

ventrals; anal short, or of moderate length. Barbels none._

These fishes are abundant in the lakes and rivers of North America,

more than thirty species having been described, and many more named,

by American ichthyologists. Two species are known from North-Eastern

Asia. They are generally called “Suckers,” but their vernacular

nomenclature is very arbitrary and confused. Some of the species

which inhabit the large rivers and lakes grow to a length of three

feet and a weight of fifteen pounds. The following genera may be

distinguished:--_Catostomus_, “Suckers,” “Red-horses,” “Stone-rollers,”

“White Mullets;” _Moxostoma_; _Sclerognathus_, “Buffaloes,” “Black

Horses;” and _Carpiodes_, “Spear-fish,” “Sail-fish.”

II. CYPRININA.--_Anal fin very short, with not more than five or six,

exceptionally seven, branched rays. Dorsal fin opposite ventrals.

Abdomen not compressed. Lateral line running along the median line

of the tail. Mouth frequently with barbels, never more than four in

number. Pharyngeal teeth generally in a triple series in the Old World

genera; in a double or single series in the North American forms, which

are small and feebly developed. Air-bladder present, without osseous

covering._

CYPRINUS.--Scales large. Dorsal fin long, with a more or less

strong serrated osseous ray; anal short. Snout rounded, obtuse,

mouth anterior, rather narrow. Pharyngeal teeth, 3. 1. 1.-1. 1.

3, molar-like. Barbels four.

[Illustration: Fig. 272.--The Carp, Cyprinus carpio.]

The “Carp” (_C. carpio_, “Karpfen,” “La carpe,”) is originally a

native of the East, and abounds in a wild state in China, where it

has been domesticated for many centuries; thence it was transported

to Germany and Sweden, and the year 1614 is assigned as the date of

its first introduction into England. It delights in tranquil waters,

preferring such as have a muddy bottom, and the surface partially

shaded with plants. Its food consists of the larvæ of aquatic insects,

minute testacea, worms, and the tender blades and shoots of plants. The

leaves of lettuce, and other succulent plants of a similar kind, are

said to be particularly agreeable to them, and to fatten them sooner

than any other food. Although the Carp eats with great voracity when

its supply of aliment is abundant, it can subsist for an astonishing

length of time without nourishment. In the winter, when the Carps

assemble in great numbers, and bury themselves among the mud and the

roots of plants, they often remain for many months without eating. They

can also be preserved alive for a considerable length of time out of

the water, especially if care be taken to moisten them occasionally

as they become dry. Advantage is often taken of this circumstance to

transport them alive, by packing them among damp herbage or damp linen;

and the operation is said to be unattended with any risk to the animal,

especially if the precaution be taken to put a piece of bread in its

mouth steeped in brandy!

The fecundity of these fishes is very great, and their numbers

consequently would soon become excessive but for the many enemies by

which their spawn is destroyed. No fewer than 700,000 eggs have been

found in the ovaries of a single Carp, and that, too, by no means an

individual of the largest size. Their growth is very rapid, more so

perhaps than that of any other Freshwater fish, and the size which they

sometimes attain is very considerable. In certain lakes in Germany

individuals are occasionally taken weighing thirty or forty pounds; and

Pallas relates that they occur in the Volga five feet in length, and

even of greater weight than the examples just alluded to. The largest

of which we have any account is that mentioned by Bloch, taken near

Frankfort-on-the-Oder, which weighed seventy pounds, and measured

nearly nine feet in length,--a statement the accuracy of which is very

much open to doubt.

Like other domesticated animals the Carp is subject to variation; some

individuals, especially when they have been bred under unfavourable

circumstances, have a lean and low body; others are shorter and higher.

Some have lost every trace of scales, and are called “Leather-carps;”

others retain them along the lateral line and on the back only

(“Spiegelkarpfen” of the Germans). Finally, in some are the fins much

prolonged, as in certain varieties of the Gold-fish. Cross-breeds

between the Carp and the Crucian Carp are of common occurrence.

The Carp is much more esteemed as food in inland countries than in

countries where the more delicate kinds of sea fishes can be obtained.

CARASSIUS differs from _Cyprinus_ in lacking barbels; its

pharyngeal teeth are compressed, in a single series, 4–4.

Two well-known species belong to this genus. The “Crucian Carp” (_C.

carassius_, “Karausche”) is generally distributed over Central and

Northern Europe, and extends into Italy and Siberia. It inhabits

stagnant waters only, and is so tenacious of life that it will

survive a lengthened sojourn in the smallest pools, where, however,

it remains stunted; whilst in favourable localities it attains to a

length of twelve inches. It is much subject to variation of form; very

lean examples are commonly called “Prussian Carps.” Its usefulness

consists in keeping ponds clean from a super-abundance of vegetable

growth, and in serving as food for other more esteemed fishes. The

second species is the “Gold-fish,” _Carassius auratus_. It is of very

common occurrence in a wild state in China and the warmer parts of

Japan, being entirely similar in colour to the Crucian Carp. In a

domesticated state it loses the black or brown chromatophors, and

becomes of a golden-yellow colour; perfect Albinos are comparatively

scarcer. Many varieties and monstrosities have been produced during

the long period of its domestication; the variety most highly priced

at present being the so-called “Telescope-fish,” of which a figure is

annexed. The Gold-fish is said to have been first brought to England

in the year 1691, and is now distributed over nearly all the civilised

parts of the world.

[Illustration: Fig. 273.--Cyprinus auratus, var.]

CATLA.--Scales of moderate size. Dorsal fin without osseous ray,

with more than nine branched rays, commencing nearly opposite to

the ventrals. Snout broad, with the integuments very thin; there

is no upper lip, the lower with a free continuous posterior

margin. Symphysis of the mandibulary bones loose, with prominent

tubercles. Mouth anterior. Barbels none. Gill-rakers very long,

fine, and closely set. Pharyngeal teeth, 5. 3. 2.-2. 3. 5.

The “Catla” (_C. buchanani_), one of the largest Carps of the Ganges,

growing to a length of more than three feet, and esteemed as food.

LABEO.--Scales of moderate or small size. Dorsal fin without

osseous ray, with more than nine branched rays, commencing

somewhat in advance of the ventrals. Snout obtusely rounded,

the skin of the maxillary region being more or less thickened,

forming a projection beyond the mouth. Mouth transverse,

inferior, with the lips thickened, each or one of them being

provided with an inner transverse fold, which is covered with a

deciduous horny substance forming a sharp edge, which, however,

does not rest upon the bone as base, but is soft and movable.

Barbels very small, two or four; the maxillary barbels more or

less hidden in a groove behind the angle of the mouth. Anal

scales not enlarged. Pharyngeal teeth uncinate, 5. 4. 2.-2. 4.

5. Snout generally more or less covered with hollow tubercles.

About thirteen species are known from rivers of tropical Africa and the

East Indies.

DISCOGNATHUS.--Scales of moderate size. Dorsal fin without

osseous ray, with not more than nine branched rays, commencing

somewhat in advance of the ventrals. Snout obtusely rounded,

more or less depressed, projecting beyond the mouth, more or

less tubercular. Mouth inferior, transverse, crescent-shaped;

lips broad, continuous, with an inner sharp edge of the jaws,

covered with horny substance on the lower jaw; upper lip more

or less distinctly fringed; lower lip modified into a suctorial

disk, with free anterior and posterior margins. Barbels two or

four; if two, the upper are absent. Anal scales not enlarged.

Pectoral fins horizontal. Pharyngeal teeth, 5. 4. 2.-2. 4. 5.

A small fish (_D. lamta_), extremely abundant in almost all the

mountain streams from Abyssinia and Syria to Assam.

CAPOËTA.--Scales small, of moderate or large size. Dorsal fin

with or without a strong osseous ray, with not more than nine

branched rays. Snout rounded, with the mouth transverse and at

its lower side; each mandible angularly bent inwards in front,

the anterior mandibular edge being nearly straight, sharpish,

and covered with a horny brown layer. No lower labial fold.

Barbels two (rarely four), or entirely absent. Anal scales not

conspicuously enlarged. Pharyngeal teeth compressed, truncated,

5 or 4. 3. 2–2. 3. 4 or 5.

Characteristic of the fauna of Western Asia; one species from

Abyssinia. Of the fifteen species known _C. damascina_ deserves to

be specially mentioned, being abundant in the Jordan and other rivers

of Syria and Asia Minor.

BARBUS.--Scales of small, moderate, or large size. Dorsal

fin generally with the (third) longest simple ray ossified,

enlarged, and frequently serrated; never, or only exceptionally,

with more than nine branched rays, commencing opposite or nearly

opposite to the root of the ventral fin. Eyes without adipose

eyelid. Anal fin frequently very high. Mouth arched, without

inner folds, inferior or anterior; lips without horny covering.

Barbels short, four, two, or none. Anal scales not enlarged.

Pharyngeal teeth 5. 4 or 3. 3 or 2.-2 or 3. 3 or 4. 5. Snout but

rarely with tubercles or pore-like grooves.

No other genus of Cyprinoids is composed of so many species as the

genus of “Barbels,” about 200 being known from the tropical and

temperate parts of the Old World; it is not represented in the New

World. Although the species differ much from each other in the form of

the body, number of barbels, size of the scales, strength of the first

dorsal ray or spine, etc., the transition between the extreme forms is

so perfect that no further generic subdivision should be attempted.

Some attain a length of six feet, whilst others never exceed a length

of two inches. The most noteworthy are the large Barbels of the Tigris

(_B. subquincunciatus_, _B. esocinus_, _B. scheich_, _B. sharpeyi_);

the common Barbel of Central Europe and Great Britain (_B. vulgaris_);

the “Bynni” of the Nile (_B. bynni_); _B. canis_ from the Jordan; the

“Mahaseer” of the mountain streams of India (_B. mosal_), probably the

largest of all species, the scales of which are sometimes as large as

the palm of a hand. The small, large-scaled species are especially

numerous in the East Indies and the fresh waters of Tropical Africa.

THYNNICHTHYS.--Scales small. Dorsal fin without an osseous

ray, with not more than nine branched rays, commencing nearly

opposite the ventrals. Head large, strongly compressed; eye

without well-developed adipose membrane, in the middle of

the depth of the head. Snout with the integuments very thin;

there is no upper lip, and the lower jaw has a thin labial

fold on the sides only. Mouth anterior and lateral; barbels

none. Gill-rakers none; laminæ branchiales long, half as long

as the post-orbital portion of the head; pseudobranchiæ none.

Pharyngeal teeth lamelliform, with flat oblong crown, 5. 3 or 4.

2–2. 4 or 3. 5, the teeth of the three series being wedged into

one another.

Three species from the East Indies.

OREINUS.--Scales very small. Dorsal fin with a strong osseous

serrated ray, opposite to the ventrals. Snout rounded, with the

mouth transverse, and at its lower side; mandibles broad, short,

and flat, loosely joined together; margin of the jaw covered

with a thick horny layer; a broad fringe-like lower lip, with

free posterior margin. Barbels four. Vent and anal fin in a

sheath, covered with enlarged tiled scales. Pharyngeal teeth

pointed, more or less hooked, 5. 3. 2–2. 3. 5.

Three species from mountain streams of the Himalayas.

SCHIZOTHORAX.--Hill-barbels, with the same singular sheath on

each side of the vent, as in the preceding genus; but they

differ in having the mouth normally formed, with mandibles of

the usual length and width.

Seventeen species are known from fresh waters of the Himalayas, and

north of them. Other genera from the same region, and with the anal

sheath, are _Ptychobarbus_, _Gymnocypris_, _Schizopygopsis_, and

_Diptychus_.

GOBIO.--Scales of moderate size; lateral line present. Dorsal

fin short, without spine. Mouth inferior; mandible not

projecting beyond the upper jaw when the mouth is open; both

jaws with simple lips; a small but very distinct barbel at the

angle of the mouth, quite at the extremity of the maxillary.

Gill-rakers very short; pseudobranchiæ. Pharyngeal teeth, 5. 3

or 2.--2 or 3. 5, hooked at the end.

The “Gudgeons” are small fishes of clear fresh waters of Europe;

they are, like the barbels, animal feeders. In Eastern Asia they

are represented by two closely allied genera, _Ladislavia_ and

_Pseudogobio_.

CERATICHTHYS.--Scales of moderate or small size; lateral line

present. Dorsal fin short, without spine, not or but slightly

in advance of the ventrals. Mouth subinferior; the lower jaw

does not project beyond the upper when the mouth is open;

intermaxillaries protractile from below the maxillaries; both

jaws with thickish lips; a small barbel at the angle of the

mouth, quite at the extremity of the maxillary. Gill-rakers very

short and few in number: pseudobranchiæ. Pharyngeal teeth 4–4.

hooked at the end (sometimes 4, 1--1. 4).

About ten species are known from North America; they are small, and

called “Chub” in the United States. _C. biguttatus_ is, perhaps,

the most widely-diffused Freshwater-fish in the United States, and

common everywhere. Breeding males have generally a red spot on each

side of the head.

Other similar genera from the fresh waters of North America, and

generally called “Minnows,” are _Pimephales_ (the “Black Head”),

_Hyborhynchus_, _Hybognathus_, _Campostoma_ (the “Stone-lugger”),

_Ericymba_, _Cochlognathus_, _Exoglossum_ (the “Stone Toter” or

“Cut-lips”), and _Rhinichthys_ (the “Long-nosed Dace”).

The remaining Old World genera belonging to the group _Cyprinina_ are

_Cirrhina_, _Dangila_, _Osteochilus_, _Barynotus_, _Tylognathus_,

_Abrostomus_, _Crossochilus_, _Epalzeorhynchus_, _Barbichthys_,

_Amblyrhynchichthys_, _Albulichthys_, _Aulopyge_, _Bungia_, and

_Pseudorasbora_.

III. ROHTEICHTHYINA.--_Anal fin very short, with not more than six

branched rays. Dorsal fin behind ventrals. Abdomen compressed. Lateral

line running along the median line of the tail. Mouth without barbels.

Pharyngeal teeth in a triple series._

One genus and species only, _Rohteichthys microlepis_, from Borneo and

Sumatra.

IV. LEPTOBARBINA.--_Anal fin very short, with not more than six

branched rays. Dorsal fin opposite to ventrals. Abdomen not compressed.

Lateral line running in the lower half of the tail. Barbels present,

not more than four in number. Pharyngeal teeth in a triple series._

One genus and species only, _Leptobarbus hoevenii_, from Borneo and

Sumatra.

V. RASBORINA.--_Anal fin very short, with not more than six branched

rays. Dorsal fin inserted behind the origin of the ventrals. Abdomen

not compressed. Lateral line running along the lower half of the

tail, if complete. Mouth sometimes with barbels, which are nevermore

than four in number. Pharyngeal teeth in a triple, or single series.

Air-bladder present, without osseous covering._

RASBORA.--Scales large, or of moderate size, there being

generally four and a half longitudinal series of scales between

the origin of the dorsal fin and the lateral line, and one

between the lateral line and the ventral. Lateral line curved

downwards. Dorsal fin with seven or eight branched rays, not

extending to above the anal, which is seven-rayed. Mouth of

moderate width, extending to the front margin of the orbit,

with the lower jaw slightly prominent, and provided with three

prominences in front, fitting into grooves of the upper jaw;

barbels none, in one species two. Gill-rakers short, lanceolate.

Pseudobranchiæ. Pharyngeal teeth in three series, uncinate.

Thirteen species of small size from the East Indian Continent and

Archipelago, and from rivers on the east coast of Africa.

AMBLYPHARYNGODON.--Scales small; lateral line incomplete. Dorsal

fin without an osseous ray, with not more than nine branched

rays, commencing a little behind the origin of the ventrals.

Head of moderate size, strongly compressed; eye without adipose

membrane; snout with the integuments very thin; there is no

upper lip, and the lower jaw has a short labial fold on the

sides only. Mouth anterior, somewhat directed upwards, with

the lower jaw prominent. Barbels none. Gill-rakers extremely

short; pseudobranchiæ. Pharyngeal teeth molar-like, with their

crowns concave, 3. 2. 1.--1. 2. 3. Intestinal tract narrow, with

numerous convolutions.

Three species of small size from the Continent of India.

To the same group belong _Luciosoma_, _Nuria_, and _Aphyocypris_, from

the same geographical region.

VI. SEMIPLOTINA.--_Anal fin short, with seven branched rays, not

extending forwards to below the dorsal. Dorsal fin elongate, with an

osseous ray. Lateral line running along the middle of the tail. Mouth

sometimes with barbels._

Two genera: _Cyprinion_, from Syria and Persia, and _Semiplotus_ from

Assam.

VII. XENOCYPRIDINA.--_Anal fin rather short, with seven or more

branched rays, not extending forwards to below the dorsal fin. Dorsal

short, with an osseous ray. Lateral line running along the middle of

the tail. Mouth sometimes with barbels. Pharyngeal teeth in a triple or

double series._

Three genera: _Xenocypris_ and _Paracanthobrama_ from China; and

_Mystacoleucus_ from Sumatra.

VIII. LEUCISCINA.--_Anal fin short or of moderate length, with from

eight to eleven branched rays, not extending forwards to below the

dorsal. Dorsal fin short, without osseous ray. Lateral line, if

complete, running along, or nearly in, the middle of the tail. Mouth

generally without barbels. Pharyngeal teeth in a single or double

series._

LEUCISCUS.--Body covered with imbricate scales. Dorsal fin

commencing opposite, rarely behind, the ventrals. Anal fin

generally with from nine to eleven, rarely with eight (in small

species only), and still more rarely with fourteen rays. Mouth

without structural peculiarities; lower jaw not trenchant;

barbels none. Pseudobranchiæ. Pharyngeal teeth conical or

compressed, in a single or double series. Intestinal tract

short, with only a few convolutions.

The numerous species of this genus are comprised under the name of

“White-fish;” they are equally abundant in the northern temperate

zone of both hemispheres, about forty species being known from the

Old World, and about fifty from the New. The most noteworthy species

of the former Fauna are the “Roach” (_L. rutilus_, see Fig. 21,

p. 50), common all over Europe north of the Alps; the “Chub” (_L.

cephalus_), extending into Northern Italy and Asia Minor; the “Dace”

(_L. leuciscus_), a companion of the Roach; the “Id” or “Nerfling” (_L.

idus_), from the central and northern parts of Continental Europe,

domesticated in some localities of Germany, in this condition assuming

the golden hue of semi-albinism, like a Gold-fish, and then called the

“Orfe;” the “Rudd,” or “Red-eye” (_L. erythrophthalmus_), distributed

all over Europe and Asia Minor, and distinguished by its scarlet lower

fins; the “Minnow” (_L. phoxinus_), abundant everywhere in Europe, and

growing to a length of seven inches in favourable localities. The North

American species are much less perfectly known; the smaller ones are

termed “Minnows,” the larger “Shiner” or “Dace.” The most common are

_L. cornutus_ (Red-fin, Red Dace); _L. neogæus_, a minnow resembling

the European species, but with incomplete lateral line; _L. hudsonius_,

the “Spawn-eater” or “Smelt.”

TINCA.--Scales small, deeply embedded in the thick skin; lateral

line complete. Dorsal fin short, its origin being opposite the

ventral fin; anal short; caudal subtruncated. Mouth anterior;

jaws with the lips moderately developed; a barbel at the angle

of the mouth. Gill-rakers short, lanceolate; pseudobranchiæ

rudimentary. Pharyngeal teeth 4 or 5.-5, cuneiform, slightly

hooked at the end.

[Illustration: Fig. 274.--The Tench (Tinca tinca).]

Only one species of “Tench” is known (_T. tinca_), found all over

Europe in stagnant waters with soft bottom. The “Golden Tench” is only

a variety of colour, an incipient albinism like the Gold-fish and Id.

Like most other Carps of this group it passes the winter in a state of

torpidity, during which it ceases to feed. It is extremely prolific,

297,000 ova having been counted in one female; its spawn is of a

greenish colour.

LEUCOSOMUS.--Scales of moderate or small size; lateral line

present. Dorsal fin commencing opposite, or nearly opposite, to

the ventral. Anal fin short. Mouth anterior or sub-anterior;

intermaxillaries protractile. A very small barbel at the

extremity of the maxillary. Lower jaw with rounded margin, and

with the labial folds well developed laterally. Gill-rakers

short; pseudobranchiæ. Pharyngeal teeth in a double series.

A North American genus, to which belong some of the most common species

of the United States. _L. pulchellus_ (the “Fall-fish,” “Dace,” or

“Roach”), one of the largest White-fishes of the Eastern States,

attaining to a length of 18 inches, and abundant in the rapids of the

larger rivers. _L. corporalis_ (the “Chub”), common everywhere from New

England to the Missouri region.

CHONDROSTOMA.--Scales of moderate size or small. Lateral line

terminating in the median line of the depth of the tail. Dorsal

fin with not more than nine branched rays, inserted above the

root of the ventrals. Anal fin rather elongate, with ten or more

rays. Mouth inferior, transverse, lower jaw with a cutting edge,

covered with a brown horny layer. Barbels none. Gill-rakers

short, fine; pseudobranchiæ. Pharyngeal teeth 5 or 6 or 7.-7 or

6 or 5, knife-shaped, not denticulated. Peritoneum black.

Seven species from the Continent of Europe and Western Asia.

Other Old World genera belonging to the _Leuciscina_ are _Myloleucus_,

_Ctenopharyngodon_, and _Paraphoxinus_; from North America:

_Mylopharodon_, _Meda_, _Orthodon_, and _Acrochilus_.

IX. RHODEINA.--_Anal fin of moderate length, with from nine to twelve

branched rays, extending forwards to below the dorsal. Dorsal fin

short, or of moderate length. Lateral line, if complete, running along

or nearly in the middle of the tail. Mouth with very small, or without

any barbels. Pharyngeal teeth in a single series._

Very small roach-like fishes inhabiting chiefly Eastern Asia and Japan,

one species (_Rh. amarus_) advancing into Central Europe. The thirteen

species known have been distributed among four genera, _Achilognathus_,

_Acanthorhodeus_, _Rhodeus_, and _Pseudoperilampus_. In the females a

long external urogenital tube is developed annually during the spawning

season. The European species is known in Germany by the name of

“Bitterling.”

X. DANIONINA.--_Anal fin of moderate length or elongate, with not less,

and generally more, than eight branched rays. Lateral line running

along the lower half of the tail. Mouth with small, or without any,

barbels. Abdomen not trenchant. Pharyngeal teeth in a triple or double

series._

Small fishes from the East Indian Continent, Ceylon, the East Asiatic

Islands, and a few from East African Rivers, The genera belonging to

this group are _Danio_, _Pteropsarion_, _Aspidoparia_, _Barilius_,

_Bola_, _Scharca_, _Opsariichthys_, _Squaliobarbus_, and _Ochetobus_:

altogether about forty species.

XI. HYPOPHTHALMICHTHYINA.--_Anal fin elongate. Lateral line running

nearly along the median line of the tail. Mouth without barbels.

Abdomen not trenchant. No dorsal spine. Pharyngeal teeth in a single

series._

One genus (_Hypophthalmichthys_) with two species from China.

XII. ABRAMIDINA.--_Anal fin elongate. Abdomen, or part of the abdomen,

compressed._

[Illustration: Fig. 275.--The Bream (Abramis brama).]

ABRAMIS.--Body much compressed, elevated, or oblong. Scales

of moderate size. Lateral line present, running in the lower

half of the tail. Dorsal fin short, with spine, opposite to the

space between ventrals and anals. Lower jaw generally shorter,

and rarely longer than the upper. Both jaws with simple lips,

the lower labial fold being interrupted at the symphysis of

the mandible. Upper jaw protractile. Gill-rakers rather short;

pseudobranchiæ. The attachment of the branchial membrane to the

isthmus takes place at some distance behind the vertical from

the orbit. Pharyngeal teeth in one or two series, with a notch

near the extremity. Belly behind the ventrals compressed into an

edge, the scales not extending across it.

The “Breams” are represented in the temperate parts of both northern

hemispheres; in Europe there occur the “Common Bream,” _A. brama_;

the “Zope,” _A. ballerus_; _A. sapa_; the “Zärthe,” _A. vimba_; _A.

elongatus_; the “White Bream,” _A. blicca_; _A. bipunctatus_. Of these

_A. brama_ and _A. blicca_ are British; the former being one of the

most common fishes, and sometimes attaining to a length of two feet.

Crosses between these two species, and even with other Cyprinoids, are

not rare. Of the American species _A. americanus_ (“Shiner,” “Bream”)

is common and widely distributed; like the European Bream it lives

chiefly in stagnant waters or streams with a slow current.

ASPIUS.--Body oblong; scales of moderate size; lateral line

complete, terminating nearly in the middle of the depth of the

tail. Dorsal fin short, without spine, opposite to the space

between the ventrals and anal; anal fin elongate, with thirteen

or more rays. Lower jaw more or less conspicuously projecting

beyond the upper. Lips thin, simple, the lower labial fold being

at the symphysis; upper jaw but little protractile. Gill-rakers

short and widely set; pseudobranchiæ. The attachment of the

branchial membrane to the isthmus takes place below the hind

margin of the orbit. Pharyngeal teeth hooked, 5. 3.-3 or 2. 5 or

4. Belly behind the ventrals compressed, the scales covering the

edge.

Four species from Eastern Europe to China.

ALBURNUS.--Body more or less elongate; scales of moderate size;

lateral line present, running below the median line of the

tail. Dorsal fin short, without spine, opposite to the space

between ventrals and anal; anal fin elongate, with more than

thirteen rays. Lower jaw more or less conspicuously projecting

beyond the upper. Lips thin, simple, the lower labial fold

being interrupted at the symphysis of the mandible. Upper jaw

protractile. Gill-rakers slender, lanceolate, closely set;

pseudobranchiæ. The attachment of the branchial membrane to

the isthmus takes place below the hind margin of the orbit.

Pharyngeal teeth in two series, hooked. Belly behind the

ventrals compressed into an edge, the scales not extending

across it.

“Bleak” are numerous in Europe and Western Asia, fifteen species

being known. The common Bleak (_A. alburnus_) is found north of the

Alps only, and represented by another species (_A. alburnellus_,

“Alborella,” or “Avola”) in Italy.

Of the other genera referred to this group, _Leucaspius_ and _Pelecus_

belong to the European Fauna; _Pelotrophus_ is East African; all

the others occur in the East Indies or the temperate parts of

Asia, viz. _Rasborichthys_, _Elopichthys_, _Acanthobrama_ (Western

Asia), _Osteobrama_, _Chanodichthys_, _Hemiculter_, _Smiliogaster_,

_Toxabramis_, _Culter_, _Eustira_, _Chela_, _Pseudolabuca_, and

_Cachius_.

XIII. HOMALOPTERINA.--_Dorsal and anal fins short, the former opposite

to ventrals. Pectoral and ventral fins horizontal, the former with the

outer rays simple. Barbels six or none. Air-bladder absent. Pharyngeal

teeth in a single series, from ten to sixteen in number._

Inhabitants of hill-streams in the East Indies; they are of small size

and abundant where they occur. Thirteen species are known belonging

to the genera _Homaloptera_, _Gastromyzon_, _Crossostoma_, and

_Psilorhynchus_.

XIV. COBITIDINA.--_Mouth surrounded by six or more barbels. Dorsal fin

short or of moderate length; anal fin short. Scales small, rudimentary,

or entirely absent. Pharyngeal teeth in a single series, in moderate

number. Air-bladder partly or entirely enclosed in a bony capsule.

Pseudobranchiæ none_: Loaches.

MISGURNUS.--Body elongate, compressed. No sub-orbital spine. Ten

or twelve barbels, four belonging to the mandible. Dorsal fin

opposite to the ventrals; caudal rounded.

Four species from Europe and Asia. _M. fossilis_ is the largest

of European Loaches, growing to a length of ten inches; it occurs in

stagnant waters of eastern and southern Germany and northern Asia.

In China and Japan it is replaced by an equally large species, _M.

anguillicaudatus_.

NEMACHILUS.--No erectile sub-orbital spine. Six barbels, none at

the mandible. Dorsal fin opposite to the ventrals.

The greater number of Loaches belong to this genus; about fifty species

are known from Europe and temperate Asia; such species as extend

into tropical parts inhabit streams of high altitudes. Loaches are

partial to fast-running streams with stony bottom, and exclusively

animal feeders. In spite of their small size they are esteemed as food

where they occur in sufficient abundance. The British species, _N.

barbatulus_, is found all over Europe except Denmark and Scandinavia.

COBITIS.--Body more or less compressed, elongate; back not

arched. A small, erectile, bifid sub-orbital spine below the

eye. Six barbels only on the upper jaw. Dorsal fin inserted

opposite to ventrals. Caudal rounded or truncate.

Only three species are known, of which _C. tænia_ occurs in Europe. It

is scarce and very local in Great Britain.

BOTIA.--Body compressed, oblong; back more or less arched. Eyes

with a free circular eyelid; an erectile bifid sub-orbital

spine. Six barbels on the upper jaw, sometimes two others at the

mandibulary symphysis. Dorsal fin commencing in advance of the

root of the ventrals; caudal fin forked. Air-bladder consisting

of two divisions: the anterior enclosed in a partly osseous

capsule, the posterior free, floating in the abdominal cavity.

[Illustration: Fig. 276.--Botia rostrata. From Bengal.]

This genus is more tropical than any of the preceding, and the majority

of the species (eight in number) are finely coloured. The more elevated

form of their body, and the imperfect ossification of the capsules of

the air-bladder, the divisions of which are not side by side, but

placed in the longitudinal axis of the body, indicate likewise that

this genus is more adapted for still waters of the plains than for the

currents of hill-streams.

Other genera from tropical India are _Lepidocephalichthys_,

_Acanthopsis_, _Oreonectes_ (hills near Hong-Kong), _Paramisgurnus_

(Yan-tse-Kiang), _Lepidocephalus_, _Acanthophthalmus_, and _Apua_.

FOURTH FAMILY--KNERIIDÆ.

_Body scaly, head naked. Margin of the upper jaw formed by the

intermaxillaries. Dorsal and anal fins short, the former belonging

to the abdominal portion of the vertebral column. Teeth none, either

in the mouth or pharynx. Barbels none. Stomach siphonal; no pyloric

appendages. Pseudobranchiæ none. Branchiostegals three; air-bladder

long, not divided. Ovaries closed._

Small loach-like fishes from fresh waters of tropical Africa; two

species only, _Kneria angolensis_ and _K. spekii_, are known.

FIFTH FAMILY--CHARACINIDÆ.

_Body covered with scales, head naked; barbels none. Margin of the

upper jaw formed by the intermaxillaries in the middle and by the

maxillaries laterally. Generally a small adipose fin behind the dorsal.

Pyloric appendages more or less numerous; air-bladder transversely

divided into two portions, and communicating with the organ of hearing

by means of the auditory ossicles. Pseudobranchiæ none._

The fishes of this family are confined to the fresh waters of Africa,

and especially of tropical America, where they replace the Cyprinoids,

with which family, however, they have but little in common as far as

their structural characteristics are concerned. Their co-existence

in Africa with Cyprinoids proves only that that continent is nearer

to the original centre, from which the distribution of Cyprinoids

commenced than tropical America. The family includes herbivorous as

well as strictly carnivorous forms; some are toothless, whilst others

possess a most formidable dentition. The family contains so many

diversified forms as to render a subdivision into groups necessary.

They have not yet been obtained in fossiliferous strata.

I. ERYTHRININA.--_Adipose fin absent._

The sixteen species of this group belong to the fauna of tropical

America, and are referred to the genera _Macrodon_, _Erythrinus_,

_Lebiasina_, _Nannostomus_, _Pyrrhulina_, and _Corynopoma_.

II. CURIMATINA.--_A short dorsal and an adipose fin; dentition

imperfect. Tropical America._

CURIMATUS.--Dorsal fin placed nearly in the middle of the body;

anal rather short or of moderate length; ventrals below the

dorsal. Body oblong or elevated, with the belly rounded or

flattened before the ventrals. Cleft of the mouth transverse,

lips none, margins of the jaws trenchant. No teeth whatever.

Intestinal tract very long and narrow.

About twenty species are known, of rather small size.

The other genera of this group have teeth, but they are either

rudimentary or absent in some part of the jaws: _Prochilodus_,

_Cænotropus_, _Hemiodus_, _Saccodon_, _Parodon_.

III. CITHARININA.--_A rather long dorsal and an adipose fin; minute

labial teeth. Tropical Africa._

One genus only, _Citharinus_, with two species, is known. Common in the

Nile, attaining to a length of three feet.

IV. ANASTOMATINA.--_A short dorsal and an adipose fin; teeth in both

jaws well developed; the gill-membranes grown to the isthmus; nasal

openings remote from each other. Tropical America._

LEPORINUS.--Dorsal fin placed nearly in the middle of the length

of the body; anal short; ventrals below the dorsal. Body oblong,

covered with scales of moderate size; belly rounded. Cleft of

the mouth small, with the lips well developed; teeth in the

intermaxillary and mandible, few in number, flattened, with the

apex more or less truncated, and not serrated; the middle pair

of teeth is the longest in both jaws; palate toothless.

This genus is generally distributed in the rivers east of the Andes;

about twenty species are known, some of which, like _L. frederici_, _L.

megalepis_, are very common. They are well marked by black bands or

spots, and rarely grow to a length of two feet, being generally much

smaller.--The other genera belonging to this group are _Anastomus_ and

_Rhytiodus_.

V. NANNOCHARACINA.--_A short dorsal and an adipose fin; teeth in both

jaws well developed; notched incisors. The gill-membranes are grown to

the isthmus. Nostrils close together._

One genus, _Nannocharax_, with two species only, from the Nile and

Gaboon; very small.

VI. TETRAGONOPTERINA.--_A short dorsal and an adipose fin; the teeth

in both jaws well developed, compressed, notched, or denticulated; the

gill-membranes free from the isthmus, and the nasal openings close

together. South America and Tropical Africa._

ALESTES.--The dorsal fin is placed in the middle of the length

of the body, above or behind the ventrals; anal fin rather

long. Body oblong, covered with scales of moderate or large

size; belly rounded. Cleft of the mouth rather small. Maxillary

teeth none; intermaxillary teeth in two series; those of the

front series more or less compressed, more or less distinctly

tricuspid; the teeth of the hinder series are broad, molar-like,

each armed with several pointed tubercles. Teeth in the

lower jaw in two series; those in the front series laterally

compressed, broader behind than in front; the hinder series is

composed of two conical teeth. All the teeth are strong, few in

number.

Fourteen species from Tropical Africa; several inhabit the Nile, of

which the “Raches” (_A. dentex_ and _A. kotschyi_) are the most common.

TETRAGONOPTERUS.--The dorsal fin is placed in the middle

of the length of the body, above or immediately behind the

ventrals; anal fin long. Body oblong or elevated, covered with

scales of moderate size; belly rounded. Cleft of the mouth of

moderate width. Anterior teeth strong, lateral teeth small.

Intermaxillary and mandibulary teeth subequal in size, with

a compressed and notched crown, the former in a double, the

latter in a single series; maxillary with a few teeth near its

articulation, rarely with the entire edge denticulated.

Of all the genera of this family _Tetragonopterus_ is represented by

the greatest number of species; about fifty are known. Some of them

seem to have a very wide range, whilst others are merely local. All are

of small size, rarely exceeding a length of eight inches.

CHIRODON.--Dorsal fin placed in the middle of the length of the

body, behind the ventrals; anal long or of moderate length. Body

oblong, covered with scales of moderate size; lateral line not

continued to the tail. Belly rounded before the ventrals. Cleft

of the mouth narrow, maxillary short. A single series of small

serrated teeth in the intermaxillary and mandibulary; maxillary

teeth none.

[Illustration: Fig. 277.--Chirodon alburnus.]

Three species of small size from various parts of South America; the

species figured is represented of the natural size, and comes from the

Upper Amazons.

MEGALOBRYCON.--Dorsal fin placed in middle of the length of

the body, immediately behind the ventrals. Anal long. Abdomen

rounded in front of, and somewhat compressed behind, the

ventrals. Cleft of the mouth of moderate width. Teeth notched,

in a triple series in the intermaxillary, and in a single in the

maxillary and mandible; no other teeth behind the mandibulary

teeth or on the palate. Scales of moderate size, with the free

portion striated.

One species from the Upper Amazons (_M. cephalus_). Specimens more

than one foot long have been obtained.

[Illustration: Fig. 278.--Megalobrycon cephalus.]

GASTROPELECUS.--Dorsal fin placed behind the middle of the

length of the body, above the anal; anal long; pectoral long;

ventrals very small or rudimentary. Body strongly compressed,

with the thoracic region dilated into a sub-semicircular disk.

Scales of moderate size. Lateral line descending obliquely

backwards towards the origin of the anal fin. The lower profile

compressed into an acute ridge. Cleft of the mouth of moderate

width; teeth compressed, tricuspid, in one or two series in the

intermaxillary, and in a single in the mandible; maxillary with

a few minute conical teeth; palate toothless.

Three specimens of this singular form are known from Brazil and the

Guyanas; they are of very small size.

The majority of the other genera belonging to this group are South

American, viz. Piabucina, Scissor, _Pseudochalceus_, _Aphyocharax_,

_Chalceus_, _Brycon_, _Chalcinopsis_, _Bryconops_, _Creagrutus_,

_Chalcinus_, _Piabuca_, _Paragoniates_, and _Agoniates_; two only

are African, viz. _Nannæthiops_, which represents the South American

_Tetragonopterus_, and _Bryconæthiops_, which is allied to Brycon.

VII. HYDROCYONINA.--_A short dorsal and an adipose fin_; _teeth in

both jaws well developed and conical; gill membranes free from the

isthmus; nasal openings close together. South America and Tropical

Africa. Fishes of prey._

HYDROCYON.--The dorsal fin is in the middle of the length of the

body, above the ventrals; anal of moderate length. Body oblong,

compressed, covered with scales of moderate size; belly rounded.

Cleft of the mouth wide, without lips; the intermaxillaries and

mandibles are armed with strong pointed teeth, widely set and

few in number; they are received in notches of the opposite

jaw, and visible externally when the mouth is closed. Palate

toothless. Cheeks covered with the enlarged sub-orbital bones.

Orbit with an anterior and posterior adipose eyelid. Intestinal

tract short.

Four species from Tropical Africa; two occur in the Nile, _H.

forskalii_ being abundant, and well known by the names “Kelb el

bahr” and “Kelb el moyeh.” Their formidable dentition renders them most

destructive to other fishes; they grow to a length of four feet.

CYNODON.--Dorsal fin placed behind, or nearly in, the middle of

the length of the body, behind the ventrals; anal long. Head

and body compressed, oblong, the latter covered with very small

scales; belly compressed, keeled. Teeth in the intermaxillary,

maxillary, and mandible in a single series, conical, widely set,

of unequal size; a pair of very large canine teeth anteriorly

in the lower jaw, received in two grooves on the palate; palate

with patches of minute granulated teeth. The outer branchial

arch without gill-rakers, but with very short tubercles.

Four species from Brazil and the Guyanas; they are as formidable fishes

of prey as the preceding, and grow to the same size.

With the exception of _Sarcodaces_, all the remaining genera of this

group belong to the fauna of Tropical America, viz. _Anacyrtus_,

_Hystricodon_, _Salminus_, _Oligosarcus_, _Xiphorhamphus_, and

_Xiphostoma_.

VIII. DISTICHODONTINA.--_Dorsal fin rather elongate; adipose fin

present. Gill-membranes attached to the isthmus; belly rounded.

Tropical Africa._

The species, ten in number, belong to one genus only (_Distichodus_),

well known on the Nile under the name of “Nefasch.” They grow to a

considerable size, being sometimes four feet long and one and a half

foot deep. They are used as food.

IX. ICHTHYBORINA.--_An adipose fin; number of dorsal rays increased

(12–17); gill-membranes free from the isthmus. Belly rounded; canine

teeth. Tropical Africa._

Two genera only: _Ichthyborus_ from the Nile, and _Phago_ from West

Africa. Small fishes of very rare occurrence.

X. CRENUCHINA.--_Dorsal fin rather elongate; an adipose fin.

Gill-membranes free from the isthmus, with the belly rounded, and

without canine teeth._

This small group is represented in the Essequibo by a single species,

_Crenuchus spilurus_, and by another in West Africa, _Xenocharax

spilurus_.

XI. SERRASALMONINA.--_Dorsal fin rather elongate; an adipose fin.

Gill-membranes free from the isthmus; belly serrated. Tropical America._

Although the fishes of this family do not attain any considerable size,

the largest scarcely exceeding two feet in length, their voracity,

fearlessness, and number renders them a perfect pest in many rivers of

tropical America. In all, the teeth are strong, short, sharp, sometimes

lobed incisors, arranged in one or more series; by means of them

they cut off a mouthful of flesh as with a pair of scissors; and any

animal falling into the water where these fishes abound is immediately

attacked and cut in pieces in an incredibly short time. They assail

persons entering the water, inflicting dangerous wounds before the

victims are able to make their escape. In some localities it is

scarcely possible to catch fishes with the hook and line, as the fish

hooked is immediately attacked by the “Caribe” (as these fishes are

called), and torn to pieces before it can be withdrawn from the water.

The Caribes themselves are rarely hooked, as they snap the hook or

cut the line. The smell of blood is said to attract at once thousands

of these fishes to a spot. They are most abundant in the Brazils and

Guyanas; some forty species are known, and referred to the genera

_Mylesinus_, _Serrasalmo_, _Myletes_, and _Catoprion_.

[Illustration: Fig. 279.--Serrasalmo scapularis, from the Essequibo.]

SIXTH FAMILY--CYPRINODONTIDÆ.

_Head and body covered with scales; barbels none. Margin of the upper

jaw formed by the intermaxillaries only. Teeth in both jaws; upper

and lower pharyngeals with cardiform teeth. Adipose fin none; dorsal

fin situated on the hinder half of the body. Stomach without blind

sac; pyloric appendages none. Pseudobranchiæ none; air-bladder simple,

without ossicula auditus._

Small fishes, inhabiting fresh, brackish, and salt water of Southern

Europe, Africa, Asia, and America. The majority are viviparous; and to

facilitate copulation the anal fin of the adult male of many species

is modified into a copulatory organ, which is probably (partially at

least) introduced into the vulva of the female; but it is uncertain

whether it serves to conduct the semen, or merely to give the male

a firmer hold of the female during the act. Also secondary sexual

differences are developed in the Cyprinodonts; the males are always

the smaller, sometimes several times smaller than the females, quite

diminutive; and they are perhaps the smallest fishes in existence. The

fins generally are more developed in the males, and the coloration is

frequently different also. Some species are carnivorous; others live

on the organic substances mixed with mud. Fossil remains have been

found in tertiary strata, all apparently referable to the existing

genus _Cyprinodon_; they occur near Aix in Provence, in the marl

of Gesso, St. Angelo, in the Brown coal near Bonn, near Frankfort,

and in the freshwater-chalk of Oeningen. In the latter locality a

_Poecilia_ occurs likewise.

The genera can be divided into two groups:

I. CYPRINODONTIDÆ CARNIVORÆ.--_The bones of each ramus of the mandible

are firmly united; intestinal tract short, or but little convoluted.

Carnivorous or insectivorous._

CYPRINODON.--Cleft of the mouth small, developed laterally and

horizontally. Snout short. Teeth of moderate size, incisor-like,

notched, in a single series. Scales rather large. Origin of the

anal fin behind that of the dorsal in both sexes, both fins

being larger in the male than in the female. Anal not modified

into a sexual organ.

Seven species occur in the Mediterranean region, all of which seem

able to live in briny springs or pools, the water of which contains a

much greater percentage of salts than sea-water, as the brine-springs

near the Dead Sea or in the Sahara. They are as little affected by

the high temperature of some of these springs (91°), for instance

of that at Sidi Ohkbar in the Sahara. Like other fishes living in

limited localities or concealing themselves in mud, Cyprinodonts lose

sometimes their ventral fins; such specimens have been described as

_Tellia_. The species of the New World are less known than those

of the Old, but not less numerous.

Allied to Cyprinodon are _Fitzroyia_ from Monte Video, and _Characodon_

from Central America.

HAPLOCHILUS.--Snout flat, both jaws being much depressed, and

armed with a narrow band of villiform teeth. Body oblong,

depressed anteriorly, compressed posteriorly. Dorsal fin short,

commencing behind the origin of the anal, which is more or less

elongate.

Twenty species from the East Indies, tropical Africa, and temperate and

tropical America.

FUNDULUS.--Cleft of the mouth of moderate width, developed

laterally and horizontally. Snout of moderate length. Teeth

in a narrow band, those of the outer series being largest,

conical. Scales of moderate size. Dorsal fin commencing before

or opposite the origin of the anal. Sexes not differentiated.

“Killifish,” abundant in the New World, where about twenty species have

been found; _F. heteroclitus_, _majalis_, _diaphanus_, being common on

the Atlantic coast of the United States; from the Old World two species

only are known, viz. _F. hispanicus_ from Spain, and _F. orthonotus_

from the east coast of Africa. Allied to _Fundulus_ are the South

American _Limnurgus_, _Lucania_, _Rivulus_, and _Cynolebias_.

ORESTIAS.--Ventral fins none. Cleft of the mouth of moderate

width, directed upwards, with the lower jaw prominent, and with

the upper protractile. Both jaws with a narrow band Of small

conical teeth. Scales rather small or of moderate size, those

on the head and upper part of the trunk frequently enlarged,

plate-like, and granulated. Dorsal and anal fins moderately

developed, opposite to each other. Sexes not differentiated by

modification of the anal fin. The gill-membranes of both sides

are united for a short distance, and not attached to the isthmus.

Inhabitants of Lake Titicaca and other elevated sheets of water on the

Cordilleras of Peru and Bolivia, between the 14th and 19th degrees of

latitude, at an elevation of 13,000 and 14,000 feet above the level

of the sea. Singularly, the fishes of this outlying genus attain to a

greater size than any other members of this family, being about eight

inches long and comparatively bulky. They are considered a delicacy.

Six species.

JENYNSIA.--Cleft of the mouth small, developed laterally and

horizontally; snout not produced. Both jaws with a series of

tricuspid teeth of moderate size. Scales of moderate size.

The origin of the anal fin is, in both sexes, behind that of

the dorsal, although the anal of the male is modified into an

intromittent organ, in which scarcely any of the rays remain

distinct.

One species from Maldonado.

[Illustration: Fig. 280.--Gambusia punctata, from Cuba. A. Male;

B. Female.]

GAMBUSIA.--Cleft of the mouth developed laterally and

horizontally. Snout not produced, with the lower jaw more or

less prominent. Both jaws with a band of teeth, those of the

outer series being strongest and conical. Scales rather large.

Origin of the anal fin more or less in advance of that of the

dorsal. Anal fin of the male modified into an intromittent organ

and much advanced.

Eight species from the West Indies and the southern parts of South

America.--Allied genera are the Central American _Pseudoxiphophorus_

and _Belonesox_.

ANABLEPS.--Head broad and depressed, with the supraorbital

part very much raised. Body elongate, depressed anteriorly

and compressed posteriorly. Cleft of the mouth horizontal, of

moderate width, the mandible being short; upper jaw protractile.

Both jaws armed with a band of villiform teeth, those of the

outer series being largest and somewhat movable. The integuments

of the eye are divided into an upper and lower portion by a

dark-coloured transverse band of the conjunctiva; also the pupil

is completely divided into two by a pair of lobes projecting

from each side of the iris. Scales rather small or of moderate

size. Dorsal and anal fins short, the former behind the latter.

The anal fin of the male is modified into a thick and long scaly

conical organ with an orifice at its extremity.

Three species from tropical America. They are the longest Cyprinodonts,

attaining to the length of nearly twelve inches. Their peculiar habit

of swimming with part of the head out of the water has been noticed

above (p. 113).

II. CYPRINODONTIDÆ LIMNOPHAGÆ.--_The bones of each ramus of the

mandible are but loosely joined; intestinal tract with numerous

circumvolutions. Sexes differentiated. Mud-eating. Tropical America._

POECILIA.--Cleft of the mouth small, transverse; mandible very

short. Both jaws with a narrow band of minute teeth. Scales

rather large. Origin of the anal fin generally nearly opposite

to that of the dorsal fin in the female, but in the male it is

modified into an intromittent organ and much advanced. Dorsal

fin short, with not more than eleven rays.

Sixteen species.

MOLLIENESIA.--Differing from _Poecilia_ in having a larger

dorsal fin, with twelve or more rays.

Five species. The males are most beautifully coloured, and their

dorsal fin is much enlarged. In one species (_M. hellerii_), besides,

the lower caudal rays of the mature male are prolonged into a long,

sword-shaped, generally black and yellow appendage.

Two other genera belong to this group: _Platypoecilus_ and _Girardinus_.

SEVENTH FAMILY--HETEROPYGII.

_Head naked; body covered with very small scales; barbels none.

Margin of the upper jaw formed, by the intermaxillaries. Villiform

teeth in the jaws and on the palate. Adipose fin none. Dorsal fin

belonging to the caudal portion of the vertebral column, opposite to

the anal. Ventral fins rudimentary or absent. Vent situated before the

pectorals. Stomach coecal; pyloric appendages present. Pseudobranchiæ

none; air-bladder deeply notched anteriorly._

To this small family, which is closely allied to the Cyprinodonts and

Umbridæ, belongs the famous Blind Fish of the Mammoth Cave in Kentucky,

_Amblyopsis spelæus_. It is destitute of external eyes, and the

body is colourless; although the eyes, with the optic nerve, are quite

rudimentary, the optic lobes are as much developed as in fishes with

perfect eyes. The loss of vision is compensated by the acuteness of

its sense of hearing, as well as by a great number of tactile papillæ,

arranged on transverse ridges on the head, and provided with nervous

filaments coming from the fifth pair. The ovary is single, and the

fish is viviparous, like the Cyprinodonts. It seems to occur in all

the subterranean rivers that flow through the great limestone region

underlying the carboniferous rocks in the central portion of the United

States. As in _Cyprinodon_, so in this genus, specimens occur

without ventral fins; they have been called _Typhlichthys_. The

largest size to which _Amblyopsis_ grows is five inches.

_Chologaster_ is closely allied, but provided with small external

eyes; its body is coloured, but it is destitute of ventrals. It was

found once in a rice field in South Carolina.

[See Tellkampf, Müll. Arch. 1844, p. 381; Packard and Putnam,

“The Mammoth Cave and its Inhabitants.” Salem. 1872. 8^o.]

EIGHTH FAMILY--UMBRIDÆ.

_Head and body covered with scales; barbels none. Margin of the upper

jaw formed by the intermaxillaries mesially, and by the maxillaries

laterally. Adipose fin none; the dorsal fin belongs partly to the

abdominal portion of the vertebral column. Stomach siphonal; pyloric

appendages none; pseudobranchiæ glandular, hidden; air-bladder

simple._

Two small species only are known: _Umbra krameri_ from Austria and

Hungary, and _Umbra limi_, locally distributed in the United States;

called “Hunds-fish” in Germany, “Dog-fish” or “Mud-fish” in America.

NINTH FAMILY--SCOMBRESOCIDÆ.

_Body covered with scales; a series of keeled scales along each side

of the belly. Margin of the upper jaw formed by the intermaxillaries

mesially, and by the maxillaries laterally. Lower pharyngeals united

into a single bone. Dorsal fin opposite the anal, belonging to the

caudal portion of the vertebral column. Adipose fin none. Air-bladder

generally present, simple, sometimes cellular, without pneumatic

duct. Pseudobranchiæ hidden, glandular. Stomach not distinct from the

intestine, which is quite straight, without appendages._

The fishes of this family are chiefly marine, some living in the open

ocean, whilst others have become acclimatised in fresh water; many of

the latter are viviparous, all the marine forms being oviparous. They

are found in all the temperate and tropical zones. Carnivorous.

This family is represented in the strata of Monte Bolca by rare remains

of a fish named _Holosteus_, allied to _Belone_ or _Scombresox_, and

by a species of _Belone_ in the miocene of Licata.

BELONE.--Both jaws are prolonged into a long slender beak. All

the dorsal and anal rays connected by membrane.

The long upper jaw of the “Gar-pike” is formed by the intermaxillaries,

which are united by a longitudinal suture. Both jaws are beset with

asperities, and with a series of longer, conical-pointed, widely-set

teeth. Skimming along the surface of the water, the Gar-pike seize

with these long jaws small fish as a bird would seize them with its

beak; but their gullet is narrow, so that they can swallow small fish

only. They swim with an undulating motion of the body; although they

are in constant activity, their progress through the water is much

slower than that of the Mackerels, the shoals of which sometimes

appear simultaneously with them on our coasts. Young specimens are

frequently met in the open ocean; when very young their jaws are not

prolonged, and during growth the lower jaw is much in advance of the

upper, so that these young fishes resemble a _Hemirhamphus_. About

fifty species are known from tropical and temperate seas, _Belone

belone_ being a common fish on the British coast. Its bones, like

those of all its congeners, are green; and therefore the fish, although

good eating, is disliked by many persons. Some species attain a length

of five feet.

SCOMBRESOX.--Both jaws are prolonged into a long slender beak. A

number of detached finlets behind the dorsal and anal fins.

The “Saury” or “Skipper” resemble the Gar-pike, but the teeth in the

jaws are minute; they seem to feed chiefly on soft pelagic animals. In

their habits they are still more pelagic; and the young, in which the

beak is still undeveloped, are met with everywhere in the open ocean,

in the Atlantic as well as in the Pacific. The European species,

_Sc. saurus_, is not rare on the British coast; four other species

have been described, closely allied to _Sc. saurus_.

HEMIRHAMPHUS.--The lower jaw only is prolonged into a long

slender beak.

In the young both jaws are short; the upper is never prolonged, the

intermaxillaries forming a triangular, more or less convex, plate.

The “Half-beaks” are common between and near the tropics; some forty

species are known, none of which attain to the same length as the

Gar-pike, scarcely ever exceeding a length of two feet. Some of the

tropical species live in fresh water only; they are of small size and

viviparous.

ARRHAMPHUS.--Mouth formed as in _Hemirhamphus_, except that the

lower jaw is not produced into a beak. Pectoral fins of moderate

length.

One species (_A. sclerolepis_) from the coast of Queensland (not

New Zealand); it may be regarded as a _Hemirhamphus_, with retarded

development of the lower jaw.

EXOCOETUS.--Jaws short, intermaxillaries and maxillaries

separate. Teeth minute, rudimental, and sometimes absent. Body

moderately oblong, covered with rather large scales. Pectorals

very long, an organ of flying.

[Illustration: Fig. 281.--Flying Fish; Exocoetus callopterus.]

Forty-four different kinds of “Flying-fishes” are known from tropical

and sub-tropical seas; some have a very wide range, whilst others seem

to remain within one particular part of the ocean; thus, the species

figured, _E. callopterus_, has been hitherto found on the Pacific

side of the isthmus of Panama only. Their usual length is about 10 or

12 inches, but specimens of 18 inches have been caught. They always

live in shoals, and their numbers at certain times and localities are

immense; thus, at Barbadoes many boats engage in their capture, as

they are excellent eating. The pectorals are in the various species of

unequal length; in some they extend to the anal fin only; in others

(and these are the best fliers) to the caudal. A few have curious,

barbel-like appendages at the lower jaw, which may disappear with age

or be persistent throughout life. The literature on the subject of

Flying-fishes is very extensive, and great diversity of opinion exists

among observers as regards the mode and power of their flight; but

the most reliable agree that the fishes do not leave the water for

the purpose of catching insects (!), and that they are unable to move

their fins in the manner of a bat or bird, or to change voluntarily the

direction of their flight, or to fly beyond a very limited distance.

The most recent enquiries are those of K. Möbius (“Die Bewegungen

der Fliegenden Fische durch die Luft,” Leip. 1878, 8vo), the chief

results of which may be summed up thus: Flying-fish are more frequently

observed in rough weather and in a disturbed sea than during calm; they

dart out of the water when pursued by their enemies, or frightened

by an approaching vessel, but frequently also without any apparent

cause, as is also observed in many other fishes; and they rise without

regard to the direction of the wind or waves. The fins are kept quietly

distended, without any motion, except an occasional vibration caused

by the air whenever the surface of the wing is parallel with the

current of the wind. Their flight is rapid, but gradually decreasing

in velocity, greatly exceeding that of a ship going 10 miles an hour,

and a distance of 500 feet. Generally, it is longer when the fishes

fly against than with or at an angle to the wind. Any vertical or

horizontal deviation from a straight line is not caused at the will of

the fish, but by currents of the air; thus they retain a horizontally

straight course when flying with or against the wind, but are carried

towards the right or left whenever the direction of the wind is at an

angle with that of their flight. However, it sometimes happens that

the fish during its flight immerses its caudal fin in the water, and

by a stroke of its tail turns towards the right or left. In a calm the

line of their flight is always also vertically straight, or rather

parabolic, like the course of a projectile, but it may become undulated

in a rough sea, when they are flying against the course of the waves;

they then frequently overtop each wave, being carried over it by the

pressure of the disturbed air. Flying-fishes often fall on board of

vessels, but this never happens during a calm, or from the lee side,

but during a breeze only, and from the weather side. In daytime they

avoid a ship, flying away from it; but during the night, when they

are unable to see, they frequently fly against the weather-board,

where they are caught by the current of air, and carried upwards to a

height of 20 feet above the surface of the water, while, under ordinary

circumstances, they keep close to it. All these observations point

clearly to the fact that any deflection from a straight course is due

to external circumstances, and not to voluntary action on the part of

the fish.

TENTH FAMILY--ESOCIDÆ.

_Body covered with scales; barbels none. Margin of the upper jaw

formed by the intermaxillaries mesially, and by the maxillaries

laterally. Adipose fin none; the dorsal fin belongs to the caudal

portion of the vertebral column. Stomach without blind sac; pyloric

appendages none. Pseudobranchiæ glandular, hidden; air-bladder simple;

gill-opening very wide._

This family includes one genus only, _Esox_, the “Pikes,” inhabitants

of the fresh waters of the temperate parts of Europe, Asia, and

America. The European species, _E. lucius_, inhabits all three

continents, but the North American waters harbour five, or perhaps

more, other species, of which the “Muskellunge,” or “Maskinonge” (_E.

estor_) of the Great Lakes attains to the same large size as the common

Pike. The other species are generally called “Pickerell” in the United

States.

[Illustration: Fig. 282.--The Pike. (Esox lucius.)]

Fossil Pike, belonging to the existing genus, have been found in the

freshwater-chalk of Oeningen, and in the diluvial marl of Silesia.

Remains of the common Pike occur in abundance in quaternary deposits.

ELEVENTH FAMILY--GALAXIIDÆ.

_Body naked, barbels none. Margin of the upper jaw chiefly formed

by the intermaxillaries, which are short, and continued by a thick

lip, behind which are the maxillaries. Belly rounded; adipose fin

none; dorsal opposite to anal. Pyloric appendages in small number.

Air-bladder large, simple; pseudobranchiæ none. The ova fall into the

cavity of the abdomen before exclusion._

Small freshwater fishes of the southern hemisphere, belonging to two

genera, _Galaxias_ and _Neochanna_. Of the former genus five species

are found in New Zealand, where this type is most developed, three in

New South Wales, two in Tasmania, and four in the southern extremity

of South America. Their native name in New Zealand is “Kokopu,” and

they were dignified with the name of “Trout” by the settlers before the

introduction of true Salmonidæ. They rarely exceed a length of eight

inches. _Neochanna_ is a degraded form of _Galaxias_, from which it

differs by the absence of ventral fins. This fish has hitherto been

found only in burrows, which it excavates in clay or consolidated mud,

at a distance from water.

[Illustration: Fig. 283.--Galaxias truttaceus, from Tasmania.]

TWELFTH FAMILY--MORMYRIDÆ.

_Body and tail scaly; head scaleless; barbels none. The margin of

the upper jaw is formed in the middle by the intermaxillaries, which

coalesce into a single bone, and laterally by the maxillaries. Sub-

and inter-operculum present, the latter very small. On each side of

the single parietal bone a cavity leading into the interior of the

skull, and covered with a thin bony lamella. All the fins are well

developed, in_ Mormyrus; _or caudal, anal, and ventral fins are

absent, in_ Gymnarchus. _No adipose fin. Pseudobranchiæ none;

gill-openings reduced to a short slit. Air-bladder simple. Two coeca

pylorica behind the stomach._

This family is characteristic of the freshwater fauna of tropical

Africa. Of _Mormyrus_ (including _Hyperopisus_ and _Mormyrops_),

fifty-one species are known, of which eleven occur in the Nile. Some

attain a length of three or four feet, others remain small. Their flesh

is said to have an excellent flavour. The species figured (and probably

other allied species) was an object of veneration to the ancient

Egyptians, and, therefore, frequently occurs in their emblematic

inscriptions. They abstained from eating it because it was one of three

different kinds of fishes accused of having devoured a member of the

body of Osiris, which, therefore, Isis was unable to recover when she

collected the rest of the scattered members of her husband.

[Illustration: Fig. 284.--Mormyrus oxyrhynchus.]

The _Mormyri_ possess a singular organ on each side of the tail,

without electric functions, but evidently representing a transitional

condition from muscular substance to an electric organ. It is an oblong

capsule divided into numerous compartments by vertical transverse

septa, and containing a gelatinous substance. The _Mormyri_ differ

much with regard to the extent of the dorsal and anal fins, the former

sometimes occupying the greater portion of the length of the back,

sometimes being much shorter and limited to the tail. In some the snout

is short and obtuse, in others long and decurved, with or without

appendage.

Of _Gymnarchus_ one species only is known, _G. niloticus_, which occurs

in the Nile and West African rivers, and attains a length of six

feet. The form of its body is eel-like, and each jaw is armed with a

series of incisor-like teeth. Like _Mormyrus_, _Gymnarchus_ possesses

a pseudo-electric organ, thickest on the tail, tapering in front,

and extending nearly to the head. It consists of four membranaceous

tubes intimately connected with the surrounding muscles, and

containing prismatic bodies arranged in the manner of a paternoster.

The air-bladder of Gymnarchus is cellular, very extensible, and

communicates with the dorsal side of the œsophagus by a duct possessing

a sphincter.

[See _Erdl_, Münchner Gelehrte Anzeigen, 1846, xxiii., and

_Hyrtl_, Denkschr. Akad. Wiss. Wien. 1856. xii.]

THIRTEENTH FAMILY--STERNOPTYCHIDÆ.

_Body naked, or with very thin deciduous scales; barbels none. Margin

of the upper jaw formed by the maxillary and intermaxillary, both

of which are toothed; opercular apparatus not completely developed.

Gill-opening very wide; pseudobranchiæ present or absent; air-bladder

simple, if present. Adipose fin present, but generally rudimentary.

Series of phosphorescent bodies along the lower parts. The eggs are

enclosed in the sacs of the ovarium, and excluded by oviducts._

Pelagic and Deep-sea fishes of small size.

STERNOPTYX.--Trunk much elevated and compressed, with the trunk

of the tail very short. Body covered with a silvery pigment,

without regular scales; series of phosphorescent spots run along

the lower side of the head, body, and tail. Cleft of the mouth

wide, vertical, with the lower jaw prominent. Jaws armed with

small teeth. Eyes rather large, and although lateral, directed

upwards and placed close together. Ventral fins very small. A

series of imbricate scutes runs along the abdomen, forming a

kind of serrature. The dorsal fin is short, and occupies about

the middle of the length of the fish; it is preceded by the

first commencement of the formation of a spinous dorsal, several

neural spines being prolonged beyond the dorsal muscle forming a

triangular osseous plate. Adipose fin rudimentary; anal short;

caudal forked.

These small fishes are now and then picked up in the Mediterranean

and Atlantic. According to the dredging-records of the “Challenger,”

they and the allied genera _Argyropelecus_ and _Polyipnus_ would

descend to depths of respectively 1100 and 2500 fathoms; but the form

of their body and their whole organisation render this statement very

improbable; they most likely live at a small depth during the daytime,

coming to the surface at night, like many _Scopelus_.

_Coccia_ and _Maurolicus_ are two other genera allied to the preceding.

[Illustration: Fig. 285.--Chauliodus sloanii.]

CHAULIODUS.--Body elongate, compressed, covered with exceedingly

thin and deciduous scales; series of luminous (phosphorescent)

spots run along the lower side of the head, body, and tail.

Head much compressed and elevated, with the bones thin, but

ossified, and with the opercular portion very narrow, the

interoperculum being rudimentary. Cleft of the mouth exceedingly

wide, the intermaxillary forming one half of the upper jaw.

Each intermaxillary with four long canine teeth; edge of the

maxillary finely denticulated; mandible with pointed, widely

set teeth, the anterior of which are exceedingly long; none of

the large teeth are received within the mouth. Palatine with a

single series of small pointed teeth; no teeth on the tongue.

Eye of moderate size. Pectoral and ventral fins well developed.

Dorsal fin anteriorly on the trunk, before the ventrals; adipose

fin small, sometimes fimbriated; anal short, rather close to

the caudal, which is forked. Gill-opening very wide, the outer

branchial arch extending forward to behind the symphysis of the

lower jaw; it has no gill-rakers. Branchiostegals numerous.

This genus, of which one species only (_Ch. sloanii_) is known, is

generally distributed over the great depths of the oceans, and does not

appear to be scarce; it attains to a length of 12 inches, and must be

one of the most formidable fishes of prey of the deep-sea.

Allied genera are _Gonostoma_, _Photichthys_, and _Diplophos_, all of

which have the teeth of much smaller size.

FOURTEENTH FAMILY--STOMIATIDÆ.

_Skin naked, or with exceedingly delicate scales; a hyoid barbel.

Margin of the upper jaw formed by the intermaxillary and maxillary

which are both toothed; opercular apparatus but little developed.

Gill-opening very wide; pseudobranchiæ none. The eggs are enclosed in

the sacs of the ovarium, and excluded by oviducts._

Deep-sea fishes, descending to the greatest depths, characterised by

their barbel and their formidable dentition.

[Illustration: Fig. 286.--_Astronesthes niger._ The white

spots in front of the eye are phosphorescent organs.]

Some have two dorsal fins, the posterior of which is adipose; they

belong to the genus _Astronesthes_, are the smallest of the family, and

frequently met with in the Atlantic.

The others--viz. _Stomias_, _Echiostoma_, _Malacosteus_, and

_Bathyophis_, lack the adipose fin, the rayed dorsal being opposite to

the anal. Of these the one longest known is

STOMIAS.--Body elongate, compressed, covered with exceedingly

fine and deciduous scales, which are scarcely imbricate, lying

in subhexagonal impressions; vent situated at no great distance

from the caudal fin. Head compressed, with the snout very short,

and with the cleft of the mouth very wide. Teeth pointed,

unequal in size, those of the intermaxillaries and of the

mandible being the longest; maxillary finely denticulated; vomer

with a pair of fangs; palatine bones and tongue with smaller

pointed teeth. Eye of moderate size. Opercular portion of the

head narrow. A fleshy barbel in the centre of the hyoid region.

Dorsal opposite the anal, close to the caudal; pectoral and

ventral fins feeble, the latter inserted behind the middle of

the length of the body. Series of phosphorescent dots run along

the lower side of the head, body, and tail. Gill-opening very

wide. Pyloric appendages none.

Three species are known; beside specimens which were found floating on

the surface, others have been dredged from depths varying between 450

and 1800 fathoms.

FIFTEENTH FAMILY--SALMONIDÆ.

_Body generally covered with scales; head naked; barbels none. Margin

of the upper jaw formed by the intermaxillaries mesially, and by the

maxillaries laterally. Belly rounded. A small adipose fin behind

the dorsal. Pyloric appendages generally numerous, rarely absent.

Air-bladder large, simple; pseudobranchiæ present. The ova fall into

the cavity of the abdomen before exclusion._

Inhabitants of the sea and freshwater; the majority of the marine

genera are deep-sea forms. The freshwater forms are peculiar to the

temperate and arctic zones of the Northern Hemisphere, one occurring

in New Zealand; many freshwater species periodically or occasionally

descending to the sea. One of the most valuable families of the class

of fishes. No fossils of the freshwater forms are known; but of the

marine genera, _Osmerus_ occurs in the greensand of Ibbenbusen,

and in the schists of Glaris and Licata; a species of _Mallotus_,

indistinguishable from the living _M. villosus_, occurs abundantly in

nodules of clay of unknown geological age in Greenland. Other genera,

as _Osmeroides_, _Acrognathus_, and _Aulolepis_, from the chalk of

Lewes, belong to the same fauna as species of Beryx, and were probably

deep-sea Salmonoids.

SALMO.--Body covered with small scales. Cleft of the mouth wide,

the maxillary extending to below or beyond the eye. Dentition

well developed; conical teeth in the jaw bones, on the vomer

and palatines, and on the tongue, none on the pterygoid bones.

Anal short, with less than fourteen rays. Pyloric appendages

numerous; ova large. Young specimens with dark cross-bands

(Parr-marks).

We know of no other group of fishes which offers so many difficulties

to the ichthyologist with regard to the distinction of the species

as well as to certain points in their life-history, as this genus,

although this may be partly due to the unusual attention which has been

given to their study, and which has revealed an almost greater amount

of unexplained facts than of satisfactory solutions of the questions

raised. The almost infinite variations of these fishes are dependent

on age, sex and sexual development, food, and the properties of the

water. Some of the species interbreed, and the hybrids mix again with

one of the parent species, thus producing an offspring more or less

similar to the pure breed. The _coloration_ is, first of all, subject

to variation; and consequently this character but rarely assists in

distinguishing a species, there being not one which would show in all

stages of development the same kind of coloration. The young of all the

species are _barred_; and this is so constantly the case that it may

be used as a generic or even as a family character, not being peculiar

to _Salmo_ alone, but also to _Thymallus_ and probably to _Coregonus_.

The number of bars is not quite constant, but the migratory Trout

have two (and even three) more than the River-Trout. In some waters

River-trout remain small, and frequently retain the Parr-marks all

their lifetime; at certain seasons a new coat of scales overlays the

Parr-marks, rendering them invisible for a time; but they reappear

in time, or are distinct as soon as the scales are removed. When the

Salmones have passed this “Parr” state, the coloration becomes much

diversified. The males, especially during and immediately after the

spawning time, are more intensely coloured and variegated than the

females; specimens which have not attained to maturity retaining a

brighter silvery colour, and being more similar to the female fish.

Food appears to have less influence on the coloration of the outer

parts than on that of the flesh; thus the more variegated specimens are

frequently out of condition, whilst well-fed individuals with pinkish

flesh are of a more uniform though bright coloration. Chemistry has

not supplied us yet with an analysis of the substance which gives the

pink colour to the flesh of many Salmonoids; but there is little doubt

that it is identical with, and produced by, the red pigments of many

salt- and freshwater Crustaceans, which form a favourite food of these

fishes. The water has a marked influence on the colours; Trout with

intense ocellated spots are generally found in clear rapid rivers, and

in small open Alpine pools; in the large lakes with pebbly bottom the

fish are bright silvery, and the ocellated spots are mixed with or

replaced by X-shaped black spots; in pools or parts of lakes with muddy

or peaty bottom, the trout are of a darker colour generally, and when

enclosed in caves or holes, they may assume an almost uniform blackish

coloration.

The change of scales (that is, the rapid reproduction of the worn

part of the scales) coincides in the migratory species with their

sojourn in the sea. The renovated scales give them a bright silvery

appearance, most of the spots disappearing or being overlaid and hidden

by the silvery scales. Now, some of the species, like _S. fario_,

inhabit all the different waters indicated, even brackish water, and,

in consequence, we find a great variation of colour in one and the

same species; others are more restricted in their habitat, like _S.

salar_, _S. ferox_, etc., and, therefore, their coloration may be more

precisely defined.

With regard to _size_ the various species do not present an equal

amount of variation. Size appears to depend on the abundance of food

and the extent of the water. Thus, the Salmon and the different kinds

of great Lake-trout do not appear to vary considerably in size, because

they find the same conditions in all the localities inhabited by them.

A widely spread species, however, like _S. fario_, when it inhabits

a small mountain pool with scanty food, may never exceed a weight

of eight ounces, whilst in a large lake or river, where it finds an

abundance and variety of food, it attains to a weight of fourteen

or sixteen pounds. Such large River-trout are frequently named and

described as Salmon-trout, Bull-trout, etc. Further, in Salmones, as

in the majority of fishes and tailed Batrachians, there is an innate

diversity of growth in individuals hatched from the same spawn. Some

grow rapidly and normally, others more slowly, and some remain dwarfed

and stationary at a certain stage of development.

The _proportions of the various parts of the body_ to one another vary

exceedingly in one and the same species. Beside the usual changes from

the young to the sexually mature form observed in all fishes, the snout

undergoes an extraordinary amount of alteration of shape. In the mature

male the intermaxillaries and the mandible are produced in various

degrees, and the latter is frequently more or less bent upwards. Hence

the males have the snout much more pointed and produced, and the entire

head longer, than the females; with the intermaxillary bone the teeth,

with which it is armed, are also enlarged, sometimes to four times the

size of those of the females. And if this development of the front

part of the head happens to be going on while the individual is able

to obtain only a scanty supply of food, the usual proportions of the

head and trunk are so altered that the species is very difficult to

recognise. Barren male fish approach the females in the proportions of

the head and body, but hybrid fishes do not differ in this respect from

their parents. The abundance or scarcity of food, and the disposition

or indisposition of the Salmonoids to feed, are other causes affecting

the growth or fulness of the various parts of the body. In well-fed

fishes the head is proportionally not only smaller but also shorter,

and _vice versa_.

The _fins_ vary to a certain degree. The variation in the number of

the rays is inconsiderable and of no value for specific distinction.

The caudal fin undergoes considerable changes of form with age,

and dependency upon the sexual development. Young specimens of all

species have this fin more or less deeply excised, so that the young

of a species which has the caudal emarginate throughout life, is

distinguished by a deeper incision of the fin, from the young of a

species which has it truncate in the adult state. As the individuals of

a species do not all attain to maturity at the same age and at the same

size, and as mature individuals generally have the caudal less deeply

excised than immature ones of the same age and size, it is evident that

the variations in the form of the caudal are considerable and numerous,

and that it is a very misleading character if due regard be not paid to

the age and sexual development of the fish. Further, species inhabiting

rapid streams as well as still waters show considerable variations in

the form and length of all the fins; those individuals which live in

rapid streams, being in almost constant motion and wearing off the

delicate extremities of the fins, have the fin-rays comparatively

shorter and stouter, and the fins of a more rounded form, particularly

at the corners, than individuals inhabiting ponds or lakes. Moreover,

one and the same individual may pass a part of its life in a lake, and

enter a river at certain periods, thus changing the form of its fins

almost periodically.

Finally, to complete our enumeration of these variable characters, we

must mention that in old males, during and after the spawning-season,

the _skin_ on the back becomes thickened and spongy, so that the scales

are quite invisible, being imbedded in the skin.

* * * * *

After this cursory review of variable characters we pass on to those

which are more constant, not subject to ready modification by external

circumstances; and which, therefore, ought to be noticed in every

description of a species of Salmo.

1. _The form of the præoperculum of the adult fish._ The præoperculum

is composed of a vertical (posterior) and horizontal (lower) part

(limb), both meeting at a more or less rounded angle. The development

of the lower limb is a very constant character; in some species (as

in the Salmon) it is long, in others (_S. ferox_, _S. brachypoma_)

exceedingly short. The adjoining woodcuts will readily show this

difference.

[Illustration: Fig. 287.--Præoperculum of A. Salmo salar; B.

Salmo brachypoma.]

In young specimens of all Salmonoids the præoperculum has a very short

lower limb; but whilst in some species it lengthens with age, its

development in a horizontal direction is arrested in others.

2. _The width and strength of the maxillary of the adult fish._--To

show this character in two distinct species, we have given woodcuts

of the maxillaries of females (12 inches long) of _S. fario_ and _S.

levenensis_ of the same size.

[Illustration: Fig. 288.--Maxillary of A. Salmo fario; B. Salmo

levenensis.]

In young specimens of all Salmonoids the maxillary is comparatively

shorter and broader, somewhat resembling that of _Coregonus_; yet this

bone offers a valuable character for the determination of the young

of some species; for instance, in a young _S. cambricus_ it extends

scarcely to below the centre of the eye, whilst in _S. fario_ of the

same size it reaches to, or even beyond, this point.

[Illustration: Fig. 289.--Vomerine teeth of Salmo salar (Salmon).

A. Side view. B. Lower view.]

3. _The size of the teeth, those of the intermaxillaries excepted._

4. _The arrangement, and the permanence or deciduousness of the

vomerine teeth._--In some species the vomer is normally armed with

a double or single series throughout life, although, of course, some

of the teeth are frequently accidentally lost; in others, these teeth

disappear gradually with age, the hinder ones first, so that finally

the anterior only remain. In order to ascertain the arrangement of

the teeth, it is necessary to remove the gengiva. Frequently the

teeth stand in a distinctly double or single series, or they are

placed alternately; but frequent irregularities occur which render

the character vague, or even unsafe, so that some zoologists have

rejected it entirely as unreliable. However, when a greater number of

individuals really belonging to the same species are examined, a pretty

safe conclusion may be arrived at as regards the arrangement of the

teeth.

[Illustration: Fig. 290.--Vomerine teeth of Salmo fario, lower

view.]

[Illustration: Fig. 291.--Vomerine teeth of a Charr, side view.]

5. _The form of the caudal fin_ in specimens of a given size, age,

and sexual development.

6. _A great development of the pectoral fins_, when constant in

individuals from the same locality.

7. _The size of the scales_, as indicated by the number of transverse

rows above the lateral line: one of the most constant characters.

8. _The number of vertebræ._--Considering the great number of

vertebræ in Salmonoids the constancy of this character is truly

surprising. An excess or a diminution of the normal number by two, is

of rare occurrence, and generally to be explained by the fact that

one vertebra has been abnormally divided into two, two such vertebræ

being considerably smaller than the others; or, on the other hand,

that two have merged into one centrum, which is then unusually large,

and provided with two neural spines. We have seen one case only, in

which three vertebræ were united. The number of vertebræ can be easily

ascertained in specimens destined for preservation in spirits, by an

incision made along one side of the fish, a little above the lateral

line.

9. _The number of pyloric appendages._--There can be no doubt that

this character may materially assist in fixing a species. We shall see

that in some species it varies from 30 to 50; but in others, as in the

Salmon and Charr, it has been found very constant (see Fig. 56, p.

131). If unexpected variations occur, their cause may be found in a

partial confluence of the cæca, as we have observed that specimens of

_S. levenensis_ (a species normally with from 70 to 90 cæca), had

those appendages of unusual width when the normal number was diminished.

* * * * *

We have mentioned above that many points in the _life-history_ of

the Salmonoids still remain very obscure:--

1. Johnson, a correspondent of Willughby (“Hist. Pisc.,” p. 194), had

already expressed his belief that the different Salmonoids interbreed;

and this view has since been shared by many who have observed these

fishes in nature. Hybrids between the Sewin (_S. cambricus_) and

the River Trout (_S. fario_) were numerous in the Rhymney and other

rivers of South Wales, before Salmonoids were almost exterminated by

the pollutions allowed to pass into those streams, and so variable

in their characters that the passage from one species to the other

could be demonstrated in an almost unbroken series, which might

induce some naturalists to regard both species as identical. Abundant

evidence of a similar character has accumulated, showing the frequent

occurrence of hybrids between _S. fario_ and _S. trutta_; hybrids

between _S. fario_ and species of Charr have been abundantly bred by

continental pisciculturists. In some rivers the conditions appear to

be more favourable to hybridism than in others, in which hybrids are

of comparatively rare occurrence. Hybrids between the Salmon and some

other species are very scarce everywhere. The hybrids are sexually as

much developed as the pure breed, but nothing whatever is known of

their further propagation and progeny.

2. Siebold has shown that some individuals of every species are not

sexually developed, and that such individuals differ also externally

from those normally developed. However, he appears to have gone too

far when he stated that this state of sterility extends over the whole

existence of such individuals, and that, therefore, the external

peculiarities also remain permanent throughout life. According to

Widegren this sterility is merely a temporary immaturity, and a part of

the individuals arrive at a full sexual development at a later or much

later period than others. To this we may add that many Salmonoids cease

to propagate their species after a certain age, and that all so called

overgrown individuals (that is, specimens much exceeding the usual size

of the species) are barren. Externally they retain the normal specific

characters.

The Salmon offers a most remarkable instance of irregularity as

regards the age at which the individuals arrive at maturity. Shaw

has demonstrated, in the most conclusive manner, that those small

Salmonoids, which are generally called Parr, are the offspring of the

Salmon, and that many males, from 7 to 8 inches long, have their sexual

organs fully developed, and that their milt has all the impregnating

properties of the seminal fluid of a much older and larger fish. That

this Parr is not a distinct species--as has been again maintained by

Couch--is further proved by the circumstance that these sexually mature

Parr are absolutely identical in their zoological characters with the

immature Parr, which are undoubtedly young Salmon, and that no Parr

has ever been found with mature ova. But whether these Parr produce

normal Salmon, impregnating the ova of female salmon, or mingle with

the River-trout, or whether they continue to grow and propagate their

species as fully developed Salmon, are questions which remain to be

answered. We may only add that, as far as we know, barren old Salmon

are extremely scarce.

3. The question whether any of the migratory species can be retained

by artificial means in fresh water, and finally accommodate themselves

to a permanent sojourn therein, must be negatived for the present.

Several instances of successful experiments made for this purpose

have been brought forward; but all these accounts are open to serious

doubts, inasmuch as they do not afford us sufficient proof that

the young fish introduced into ponds were really young migratory

Salmonoids, or that the full-grown specimens were identical with those

introduced, and not hybrids or non-migratory Trout of a somewhat

altered appearance in consequence of the change of their locality.

We have seen the experiment tried at two places in South Wales, and

in both cases the Salmon and the pure Sewin died when not allowed to

return to the sea. On the other hand, hybrid fishes from the Sewin and

the Trout survived the experiment, and continued to grow in a pond

perfectly shut up from communication with the sea. In that locality

neither those hybrids nor the trout spawn.

4. Although the majority of the mature individuals of a migratory

species ascend a river at a certain fixed time before the commencement

of spawning, others enter the freshwater at a much earlier period,

either singly or in small troops; and many appear to return to the sea

before they reascend at the time of the regular immigration. It is

not improbable that one and the same individual may change the salt-

or freshwater several times in the year. However, this is the case in

certain rivers only, for instance, in those falling into the Moray

Firth; in others one immigration only is known to occur. The cause of

the irregular ascents previous to the autumnal ascents is unknown. A

part, at least, of the hybrid fishes retain the migratory instinct; but

it is not known whether sterile individuals accompany the others in

their migrations.

5. It is said that the migratory species invariably return to the river

in which they are bred. Experiments have shown that this is normally

the case; but a small proportion appear to stray so far away from

their native place as to be unable to find their way back. Almost every

year Salmon and Sea-trout in the Grilse-state make their appearance at

the mouth of the Thames (where the migrating Salmonoids have become

extinct for many years), ready to reascend and to restock this river as

soon as its poisoned water shall be sufficiently purified to allow them

a passage.

6. There has been much dispute about the time required for the growth

of Salmonoids. The numerous and apparently contradictory observations

tend to show that there is a great amount of variation even among

individuals of the same origin living under the same circumstances,

some of them growing much more quickly than others, and being ready to

descend to the sea twelve months before their brethren. The cause of

this irregularity is not explained. On the other hand, when we consider

the fibrous condition of the Salmonoid skeleton, which is much less

solid, and more wanting in calcareous substance, than that of the

majority of Teleosteous fishes, we shall be quite prepared to adopt the

truth of the observation that the young Salmonoids return to the fresh

water, after a few months sojourn in the sea, and after having feasted

on nourishing Crustaceans, Sand-eels, etc., with their former weight in

ounces increased to pounds.

7. Liability to variation in form indicates that an animal can adapt

itself to a variety of circumstances; therefore, such species as show

the greatest pliability in this respect, are those which most recommend

themselves for domestication and acclimatisation within certain

climatic limits. Thus, the River-trout or Sea-trout were very proper

subjects for those eminently successful attempts to establish them in

similar latitudes of the Southern Hemisphere, whilst the attempt of

transferring them into the low hill-streams of India ended (as could be

foreseen) in a total failure. Those two species must now be considered

to be fully acclimatised in Tasmania and New Zealand, and with but

little protection may be expected to hold their own in the freshwaters

of those colonies. Whether the acclimatisation of the Salmon will be

in the end equally and permanently successful, remains to be seen.

The true _S. salar_ is not subject to variation, and is very

sensitive to any change of external conditions, and to every kind of

interference with its economy. The fourth species, with which attempts

of acclimatisation in Southern Australia have been made, is a migratory

Salmon from the Sacramento river in California. This experiment is

still in progress, and believed to be promising of success. It will be

a most curious problem to ascertain, how much the original characters

and habits of those species will be affected by their transference to

so distant a part of the globe. At present it would be too hazardous

to offer an opinion on this point, especially as it is a fact that

numerous cross-breeds have been introduced into, and reared in,

Tasmania, which must more or less interfere with the characters of the

pure breeds.

It is apparent, from the foregoing remarks, that the distinction

of the various species of Salmonidæ is a matter of considerable

difficulty, and that there is scope for great diversity of opinion.

At any rate it is only by a close, long-continued study, and constant

comparison of specimens of various ages and from various localities,

that one is enabled to find a guide through the labyrinth of confusing

variations. However, it is a significant fact that the very same

characters by which we are enabled to distinguish European species

occur again, though in an exaggerated form, in American Salmonoids

(which everybody will admit to be of distinct species), and therefore

our faith in them necessarily becomes strengthened. In accordance with

acknowledged principles in zoology, forms which differ from their

congeners by a combination of two or more of constant characters, are

to be distinguished under distinct specific names. Most likely they

have been derived, at a not very remote period, from common ancestors,

but the question of their specific distinctness is no more affected

by this consideration than the question whether _Salmo_ and

_Coregonus_ are distinct genera. Whenever the zoologist observes

two forms distinguished by peculiarities of organisation, such as

cannot be conceived to be the effects of an external or internal cause,

disappearing with the disappearance of that cause, and which forms

have been propagated and are being propagated uniformly through all

the generations within the limits of our observations, and are yet

most probably to be propagated during the existence of mankind, he is

obliged to describe these forms as distinct, and they will commonly be

called species.

The species of the genus _Salmo_ are inhabitants of the temperate

and arctic zones of the Northern Hemisphere; the species are most

abundant in the northern parts of the temperate zone, becoming scarcer

beyond the Arctic circle, and in the warmer parts towards the south.

The southernmost points in which Salmones are found, are, on the

American continent, the rivers falling into the head of the Californian

Gulf, and in the Old World the mountain rivers of the Atlas and Hindu

Kush. The Salmones from those localities are migratory Trout in the New

World, non-migratory and small in the Old. Those species which range

to the highest latitudes (lat. 82°) belong to the division of Charr, a

group which generally are more intolerant of a moderate temperature,

than real Trout. The genus is subdivided into

_a. Salmones_--Salmon and Trout--with teeth on the body of the

vomer as well as its head (see Figs. 289 and 290).

_b. Salvelini_--Charr--with teeth on the head of the vomer only

(see Fig. 291).

[Illustration: Fig. 292.--Salmo brachypoma.]

Of the host of species (the majority of which is unfortunately very

insufficiently characterised) we enumerate the following:--[45]

_a._ SALMONES.

1. _S. salar_ (Salmon; Lachs or Salm; Saumon) (Fig. 6, p. 43).

The Salmon can generally be readily recognised, but there are

instances in which the identification of specimens is doubtful,

and in which the following characters (besides others) will be

of great assistance. The tail is covered with relatively large

scales, there being constantly eleven, or sometimes twelve in a

transverse series running from behind the adipose fin forwards

to the lateral line, whilst there are from thirteen to fifteen

in the different kinds of Sea-trout and River-trout. The number

of pyloric appendages (see Fig. 56, p. 131) is great, generally

between 60 and 70, more rarely falling to 53 or rising to 77.

The body of the vomer is armed with a single series of small

teeth, which at an early age are gradually lost from behind

towards the front, so that half-grown and old individuals have

only a few (1–4) left. The Salmon inhabits temperate Europe

southwards to 43° N. lat., and is not found in any of the rivers

falling into the Mediterranean. In the New World its southern

boundary is 41° N. lat.

2. _S. trutta_ (Sea-trout, Salmon-trout).[46]--Especially

numerous in North Britain.

3. _S. cambricus_ (Sewin).--Wales, South of England, Ireland,

Norway, and Denmark.

4. _S. fario_ (Common River-trout).

5. _S. macrostigma_ (Algeria).

6. _S. lemanus_ (Lake of Geneva).

7. _S. brachypoma._--A migratory species from the rivers Forth,

Tweed, and Ouse.

8. _S. gallivensis_ (Galway Sea-trout).

9. _S. orcadensis._--A non-migratory trout from Lough Stennis,

in the Orkney Islands.

10. _S. ferox._--The great Lake-trout of North Britain, Wales,

and Ireland.

11. _S. stomachicus_ (the Gillaroo of Ireland).

12. _S. nigripinnis_ from mountain-pools of Wales.

13. _S. levenensis_ (Lochleven Trout).

14. _S. oxi_ from the rivers of the Hindu Kush.

15. _S. purpuratus_ from the Pacific coast of Asia and North

America.

16. _S. macrostoma._--Japan.

17. _S. namaycush._--The great Lake-trout of North America.

_b._ SALVELINI: Charr.

1. _S. umbla._--The “Ombre chevalier” of the Swiss lakes.

2. _S. salvelinus._--The “Sælbling” of the Alpine lakes of

Bavaria and Austria.

3. _S. alpinus._--The common Northern Charr, growing to a length

of four feet, and migratory.

4. _S. killinensis._--The Loch Killin Charr, Inverness-shire.

5. _S. willughbii._--The Loch Windermere Charr.

6. _S. perisii._--The “Torgoch” of Wales.

7. _S. grayi._--The “Freshwater Herring” of Lough Melvin,

Ireland.

8. _S. colii._--Charr of Loughs Eske and Dan.

9. _S. hucho._--The “Huchen” of the Danube, growing to the size

of the Salmon.

10. _S. alipes_ from lakes in Boothia Felix and Greenland.

11. _S. arcturus._--The most northern species from 82° lat.

12. _S. fontinalis._--The common “Brook-trout” of the United

States.

13. _S. oquassa._--A lake species from the State of Maine.

_Oncorhynchus_ differs from _Salmo_ only in the increased number of

anal rays, which are more than fourteen. All the species are migratory,

ascending American and Asiatic rivers flowing into the Pacific. The

Californian Salmon (_O. quinnat?_) belongs to this genus.

Other allied genera are _Brachymystax_ and _Luciotrutta_.

PLECOGLOSSUS.--Body covered with very small scales. Cleft of the

mouth wide; maxillary long. Dentition feeble; intermaxillaries

with a few small, conical, pointed teeth; the teeth of the

maxillaries and mandibles are broad, truncated, lamellated

and serrated, movable, seated in a fold of the skin. The

mandibles terminate each in a small knob, and are not jointed

at the symphysis. The mucous membrane in the interior of the

mouth--between the terminal halves of the mandibles--forms a

peculiar organ, being raised into folds, with a pair of pouches

in front and a single one behind. Tongue very small, with minute

teeth, its apical part being toothless; palate apparently

without teeth.

A small aberrant form of Freshwater-Salmonoids abundantly found in

Japan and the Island of Formosa.

OSMERUS.--Body covered with scales of moderate size. Cleft of

the mouth wide; maxillary long, extending to, or nearly to, the

hind margin of the orbit. Dentition strong; intermaxillary and

maxillary teeth small, much smaller than those of the mandible.

Vomer with a transverse series of teeth, several of which are

large, fang-like; a series of conical teeth along the palatine

and pterygoid bones. Tongue with very strong fang-like teeth

anteriorly, and with several longitudinal series of smaller

ones posteriorly. Pectoral fins moderately developed. Pyloric

appendages very short, in small number; ova small.

The “Smelt” (_O. eperlanus_) is common on many places of the coasts of

Northern Europe and America. In the sea it grows to a length of eight

inches; but, singularly, it frequently migrates from the sea into

rivers and lakes, where its growth is very much retarded. That this

habit is one of very old date, is evident from the fact that this small

freshwater form occurs, and is fully acclimatised in lakes which have

now no open communication with the sea. And still more singularly, this

same habit, with the same result, has been observed in the Smelt of New

Zealand (_Retropinna richardsonii_). The Smelt is considered a delicacy

in Europe, as well as in America, where the same species occurs. Two

other allied genera, _Hypomesus_ and _Thaleichthys_, are found on the

Pacific coast of North America, the latter being caught in immense

numbers, and known by the name “Eulachon” and “Oulachan;” it is so fat,

that it is equally used as food and as candle.

MALLOTUS.--Body covered with minute scales, which are

somewhat larger along the lateral line and along each side

of the belly; in mature males these scales become elongate,

lanceolate, densely tiled, with free projecting points, forming

villous bands. Cleft of the mouth wide; maxillary very thin,

lamelliform, extending to below the middle of the eye. Lower jaw

the longer, partly received between the maxillaries. Dentition

very feeble; the teeth forming single series; only the teeth on

the tongue are somewhat larger and disposed in an elliptical

patch. Pectoral fins large, horizontal, with broad base. Pyloric

appendages very short, in small number; ova small.

The “Capelin” (_M. villosus_) is found on the Arctic coasts of

America and of Kamtschatka. It is caught in immense numbers by the

natives, who consume it fresh, or dry it for use in the winter. Its

length does not exceed nine inches.

COREGONUS.--Body covered with scales of moderate size. Cleft of

the mouth small; maxillary broad, short or of moderate length,

not extending behind the orbit. Teeth, if present, extremely

minute and deciduous. Dorsal fin of moderate length; caudal

deeply forked. Ova small.

[Illustration: Fig. 293.--Coregonus oxyrhynchus.]

[Illustration: Fig. 294.--Head of Coregonus oxyrhynchus.]

The majority of the species, of which more than forty are known, are

lacustrine species; and comparatively few are subject to periodical

migrations to the sea, like _Salmo_. They are confined to the northern

parts of temperate Europe, Asia, and North America. Their distribution

is local, but sometimes three and more species are found in the same

lake. They abound in every lake and river of the northern parts of

North America, and are known by the name of “White-fish.” They are of

vital importance to some tribes of the native population. The European

_C. oxyrhynchus_ is as much a marine as a freshwater species. In the

British Islands several small species occur, viz. _C. clupeoides_, the

“Gwyniad,” “Schelly,” or “Powen” from the great lakes; _C. vandesius_,

the “Vendace” of Lochmaben; and _C. pollan_, the “Pollan” of the Irish

lakes. The latter is brought in quantities to Belfast market during

the season, that is, at the time when it rises from the depths of

Lough Neagh to deposit its spawn near the shore. Thomson says that in

September 1834 some 17,000 were taken there at three or four draughts

of the net. Some of the species of the continent of Europe and America

attain to a much larger size than the British species, viz. to a length

of two feet.

[Illustration: Fig. 295.--Coregonus clupeoides.]

THYMALLUS.--Principally distinguished from _Coregonus_ by its

long many-rayed dorsal fin.

“Graylings”--five species, inhabiting clear streams of the north of

Europe, Asia, and North America. The best known are the “Poisson bleu”

of the Canadian voyageurs (_Th. signifer_), and the European

Grayling (_T. vulgaris_).

SALANX.--Body elongate, compressed, naked or covered with

small, exceedingly fine, deciduous scales. Head elongate and

much depressed, terminating in a long, flat, pointed snout. Eye

small. Cleft of the mouth wide; jaws and palatine bones with

conical teeth, some of the intermaxillaries and mandibles being

enlarged; no teeth on the vomer; tongue with a single series of

curved teeth. Dorsal fin placed far behind the ventrals, but in

front of the anal; anal long; adipose fin small; caudal forked.

Pseudobranchiæ well developed; air-bladder none. The entire

alimentary canal straight, without bend; pyloric appendages

none. Ova small.

This small, transparent, or whitish fish _(S. chinensis_) is well

known at Canton and other places of the coast of China as “White-bait,”

and considered a delicacy. It is evidently a fish which lives at a

considerable depth in the sea, and approaches the coast only at certain

seasons.

Finally, this family is represented in the deep sea by three genera,

_Argentina_, _Microstoma_, and _Bathylagus_, of which the two former

live at moderate depths, and have been known for a long time, whilst

the last was discovered during the “Challenger” expedition in the

Atlantic and Antarctic Oceans at depths of 1950 and 2040 fathoms. As

_Argentina_ is sometimes found in the North Atlantic, and even near the

British coasts, we give its principal characters.

ARGENTINA.--Scales rather large; cleft of the mouth small;

intermaxillaries and maxillaries very short, not extending

to below the orbit. Eye large. Jaws without teeth; an arched

series of minute teeth across the head of the vomer and on the

fore part of the palatines; tongue armed with a series of small

curved teeth on each side. Dorsal fin short, in advance of the

ventrals; caudal deeply forked. Pseudobranchiæ well developed.

Pyloric appendages in moderate numbers. Ova small.

Four species are known, of which _A. silus_ and _A. hebridica_ have

been found occasionally on the North British, and, more frequently,

on the Norwegian coast. The other species are from the Mediterranean.

Attaining to a length of 18 inches.

SIXTEENTH FAMILY--PERCOPSIDÆ.

_Body covered with ctenoid scales; head naked. Margin of the upper

jaw formed by the intermaxillaries only; opercular apparatus complete.

Barbels none. Gill-openings wide. Adipose fin present._

One genus and species only (_Percopsis guttatus_); interesting as

having the general characters of Salmonoids, but the mouth and scales

of a Percoid. Freshwaters of the northern United States.

SEVENTEENTH FAMILY--HAPLOCHITONIDÆ.

_Body naked or scaly (cycloid). Margin of the upper jaw formed

by the intermaxillary; opercular apparatus complete. Barbels none.

Gill-opening wide; pseudobranchiæ. Air-bladder simple. Adipose fin

present. Ovaries laminated; the eggs fall into the cavity of the

abdomen, there being no oviduct. Pyloric appendages none._

[Illustration: Fig. 296.--Prototroctes oxyrhynchus, New Zealand.]

Freshwater-fishes which represent the Salmonoids in the southern

hemisphere. Two genera only are known. _Haplochiton_ (Fig. 104, p. 250)

abundant in lakes and the streams falling into the Straits of Magelhæn

and in the rivers of Chile and the Falkland Islands. It has the general

appearance of a Trout, but is naked. _Prototroctes_, with the habit of

a _Coregonus_, scaly, and provided with minute teeth; one species (_P.

maræna_) is common in South Australia, the other (_P. oxyrhynchus_) in

New Zealand. The settlers in these colonies call them Grayling; the

Maori name of the second species is “Upokororo.”

EIGHTEENTH FAMILY--GONORHYNCHIDÆ.

_Head and body entirely covered with spiny scales; mouth with

barbels. Margin of the upper jaw formed by the intermaxillary, which,

although short, is continued downwards as a thick lip, situated in

front of the maxillary. Adipose fin none; the dorsal fin is opposite to

the ventrals, and short, like the anal. Stomach simple, without blind

sac; pyloric appendages in small number. Pseudobranchiæ; air-bladder

absent. Gill-openings narrow._

[Illustration: Fig. 297.--Gonorhynchus greyi.]

[Illustration: Fig. 298.--Scale of Gonorhynchus greyi.]

One genus and species only (_Gonorhynchus greyi_) is known; it is a

semi-pelagic fish, not very rare off the Cape of Good Hope, and in the

Australian and Japanese seas. From 12 to 18 inches long. The colonists

in New Zealand name it “Sand-eel,” as it frequents bays with sandy

bottom. It is eaten.

NINETEENTH FAMILY--HYODONTIDÆ.

_Body covered with cycloid scales; head naked; barbels none. Margin

of the upper jaw formed by the intermaxillaries mesially, and by the

maxillaries laterally, the latter being articulated to the end of the

former. Opercular apparatus complete. Adipose fin none; the dorsal

fin belongs to the caudal portion of the vertebral column. Stomach

horseshoe-shaped, without blind sac; intestine short; one pyloric

appendage. Pseudobranchiæ none; air-bladder simple. Gill-openings wide.

The ova fall into the abdominal cavity before exclusion._

One genus and species only (_Hyodon tergisus_) is known, generally

called “Moon-eye.” It is abundant in the western streams and great

lakes of North America. From 12 to 18 inches long.

TWENTIETH FAMILY--PANTODONTIDÆ.

_Body covered with large cycloid scales; sides of the head osseous.

Margin of the upper jaw formed by the single intermaxillary mesially,

and by the maxillaries laterally. The dorsal fin belongs to the caudal

portion of the vertebral column, is short, opposite and similar to the

anal. Gill-openings wide; gill-covers consisting of a præoperculum

and operculum only. Branchiostegals numerous. Pseudobranchiæ none;

air-bladder simple. Stomach without coecal sac; one pyloric appendage.

Sexual organs with a duct._

A small freshwater-fish (_Pantodon buchholzi_), singularly alike to a

Cyprinodont, from the west coast of Africa.

TWENTY-FIRST FAMILY--OSTEOGLOSSIDÆ.

_Body covered with large hard scales, composed of pieces like

mosaic. Head scaleless; its integuments nearly entirely replaced by

bone; lateral line composed of wide openings of the mucus-duct. Margin

of the upper jaw formed by the intermaxillaries mesially, and by the

maxillaries laterally. The dorsal fin belongs to the caudal portion of

the vertebral column, is opposite and very similar to the anal fin;

both approximate to the rounded caudal (with which they are abnormally

confluent). Gill-openings wide; pseudobranchiæ none; air-bladder simple

or cellular. Stomach without coecal sac; pyloric appendages two._

Large freshwater-fishes of the tropics, whose singular geographical

distribution has been noticed above (p. 223).

OSTEOGLOSSUM.--Cleft of the mouth very wide, oblique, with the

lower jaw prominent. A pair of barbels at the lower jaw. Abdomen

trenchant. Bands of rasp-like teeth on the vomer, palatine and

pterygoid bones, on the tongue and hyoid. Pectoral fins elongate.

_O. bicirrhosum_ from Brazil and Guyana, _O. formosum_ from Borneo and

Sumatra, _O. leichardti_ from Queensland.

ARAPAIMA.--Cleft of the mouth wide, with the lower jaw

prominent; barbels none. Abdomen rounded. Jaws with an outer

series of small conical teeth; broad bands of rasp-like teeth

on the vomer, palatines, pterygoids, sphenoid, os linguale, and

hyoid. Pectoral fins of moderate length.

[Illustration: Fig. 299.--Arapaima gigas.]

The largest freshwater Teleostean known, exceeding a length of 15 feet

and a weight of 400 pounds. It is common in the large rivers of Brazil

and the Guyanas, and esteemed as an article of food. When salted it is

exported in large quantities from the inland fisheries to the seaports.

HETEROTIS.--Cleft of the mouth rather small, with the jaws

subequal; barbels none. A single series of small teeth in the

jaws; pterygoids and hyoid with a patch of small conical teeth;

none on the vomer or palatines.

This fish (_H. niloticus_), which is not uncommon in the Upper Nile and

the West African rivers, exhibits several anatomical peculiarities. The

fourth branchial arch supports a spiral accessory organ, the function

of which is still unexplained. The air-bladder is cellular, and the

stomach consists of a membranous and a muscular portion.

TWENTY-SECOND FAMILY--CLUPEIDÆ.

_Body covered with scales; head naked; barbels none. Abdomen

frequently compressed into a serrated edge. Margin of the upper jaw

formed by the intermaxillaries mesially, and by the maxillaries

laterally; maxillaries composed of at least three movable pieces.

Opercular apparatus complete. Adipose fin none. Dorsal not elongate;

anal sometimes very long. Stomach with a blind sac; pyloric appendages

numerous. Gill-apparatus much developed, the gill-openings being

generally very wide. Pseudobranchiæ generally present. Air-bladder more

or less simple._

The family of “Herrings” is probably unsurpassed by any other in the

number of individuals, although others comprise a much greater variety

of species. The Herrings are principally coast-fishes, or, at least, do

not go far from the shore; none belong to the deep-sea fauna; scarcely

any have pelagic habits, but many enter or live in fresh waters

communicating with the sea. They are spread over all the temperate

and tropical zones. Fossil remains of Herrings are numerous, but the

pertinence of some of the genera to this family is open to serious

doubts, as the remains are too fragmentary to allow of determining

whether they belong to Salmonoids or Clupeoids. Therefore, Agassiz

comprised both families in one--_Halecidæ_. Many of the remains

belong to recent genera, which are readily recognised, as _Clupea_,

_Engraulis_ and _Chanos_, principally from the schists of Glaris and

Licata, from Monte Bolca and the Lebanon. Others, like _Thrissopater_,

from the Gault at Folkestone, _Leptosomus_, _Opisthopteryx_,

_Spaniodon_, from the chalk and tertiary formations, can be readily

associated with recent genera. But the majority do not show an apparent

affinity to the present fauna. Thus, _Halec_ from the chalk of Bohemia,

_Platinx_ and _Coelogaster_ from Monte Bolca, _Rhinellus_ from Monte

Bolca and Mount Lebanon, _Scombroclupea_, with finlets behind the

anal, from the Lebanon and Comen, and _Crossognathus_ from tertiary

Swiss formations, allied to _Megalops_, _Spathodactylus_ from the same

locality, and _Chirocentrites_ from Mount Lebanon, etc. Finally, a

genus recently discovered in tertiary formations of Northern Italy,

_Hemitrichas_, has been classed with the Clupeoids, from which,

however, it differs by having two short dorsal fins, so that it must

be considered, without doubt, to be the representative of a distinct

family.

ENGRAULIS (including CETENGRAULIS).--Scales large or of moderate

size. Snout more or less conical, projecting beyond the lower

jaw. Teeth small or rudimentary. Intermaxillaries very small,

hidden; maxillary long, attached to the cheek by a scarcely

distensible membrane. Anal fin of moderate or great length.

Branchiostegals short, from nine to fourteen in number.

Not less than forty-three different species of “Anchovies” are known

from temperate and tropical seas. They exhibit marked differences in

the length of their maxillary bone, which sometimes does not reach the

gill-opening, whilst in other species it extends far beyond it; and in

the number of their anal rays, which varies from 20 to 80. Some have

the upper pectoral ray prolonged into a filament, thus leading towards

the succeeding genus, _Coilia_. The majority are recognised, besides,

by their peculiar structure, by a broad silvery, lateral band, similar

to that observed in the Atherines. The most celebrated Anchovy is

_E. encrasicholus_, very plentiful in the Mediterranean, but rarely

wandering northwards. It is the species which, preserved in salt,

is exported to all parts of the world, although similarly lucrative

fisheries of Anchovies might be established in Tasmania where the same

species occurs, in Chile, China, Japan, California, at Buenos Ayres,

each of which countries possesses Anchovies by no means inferior to the

Mediterranean species.

COILIA.--Body terminating in a long tapering tail. Scales of

moderate size. Snout and jaws as in _Engraulis_. Anal fin

exceedingly long, confluent with the caudal. The two or three

upper pectoral rays are much prolonged, and their branches form

four, six, or seven filaments.

[Illustration: Fig. 300.--Coilia clupeoides.]

Ten species from Indian and Chinese seas.

CHATOËSSUS.--Body compressed; abdomen serrated. Scales of

moderate size. Snout obtuse, or obtusely conical, more or less

projecting beyond the cleft of the mouth, which is narrow, more

or less transverse. Maxillary joined to the ethmoid, its upper

portion being behind the intermaxillary. Teeth none. Anal fin

rather long; dorsal opposite to the ventrals, or to the space

between ventrals and anal. Gill-membranes entirely separate;

branchial arches forming two angles, one pointing forward and

the other backwards; the fourth branchial arch with an accessory

organ; branchiostegals of moderate length, five or six in number.

Ten species from the coasts, brackish and fresh waters of Central

America (one species ranges to New York), Australia, the East Indies,

and Japan.

CLUPEA.--Body compressed, with the abdomen serrated, the

serrature extending forwards to the thorax. Scales of moderate

or large, rarely of small size. Upper jaw not projecting beyond

the lower. Cleft of the mouth of moderate width. Teeth, if

present, rudimentary and deciduous. Anal fin of moderate extent,

with less than thirty rays; dorsal fin opposite to the ventrals.

Caudal forked.

This genus comprises more than sixty different species, the

geographical distribution of which coincides with that of the family.

The majority are of greater or less utility to man, but a few tropical

species (_C. thrissa_, _C. venenosa_, and others) acquire, probably

from their food, highly poisonous properties, so as to endanger the

life of persons eating them. The most noteworthy species are--

1. _C. harengus_ (the “Herring”).--It is readily recognised by having

an ovate patch of very small teeth on the vomer. D. 17–20. A. 16–18.

L. lat. 53–59. Vert. 56. Gill-cover smooth, without radiating ridges.

It inhabits, in incredible numbers, the German Ocean, the northern

parts of the Atlantic, and the seas north of Asia. The Herring of the

Atlantic coasts of North America is identical with that of Europe. A

second species has been supposed to exist on the British coast (_C.

leachii_), but it comprises only individuals of a smaller size, the

produce of an early or late spawn. Also the so-called “White-bait” is

not a distinct species, but consists chiefly of the fry or the young

of herrings, and is obtained “in perfection” at localities where these

small fishes find an abundance of food, as in the estuary of the Thames.

[Separate accounts on the Herring may be found in Cuvier

and Valenciennes, “Hist. nat. des Poissons,” vol. xx.; J.

M. Mitchell, “The Herring, its Natural History and National

Importance,” Edinb. 1864, 8vo; P. Neucrantz, “De Harengo,”

Lübeck, 1654; J. S. Dodd, “Essay towards a Natural History

of the Herring,” Lond. 1768, 8vo; Bock, “Versuch einer

vollstændigen Natur-und Handels-Geschichte des Hærings,”

Königsberg, 1769, 8vo.]

2. _C. mirabilis._--The Herring of the North Pacific.

3. _C. sprattus._--The “Sprat.” Without vomerine teeth. D. 15–18.

A. 17–20. L. lat. 47–48. Vert. 47–49. Gill-cover, smooth, without

radiating ridges. Abundant on the Atlantic coasts of Europe.

4. _C. thrissa._--One of the most common West Indian fishes,

distinguished by the last dorsal ray being prolonged into a filament.

Hyrtl has discovered a small accessory branchial organ in this species.

5. _C. alosa._--The “Shad” or “Allice Shad,” with very fine and

long gill-rakers, from 60 to 80 on the horizontal part of the outer

branchial arch, and with one or more black lateral blotches. Coasts of

Europe, ascending rivers.

6. _C. finta._--The “Shad” or “Twaite Shad,” with stout osseous

gill-rakers, from 21 to 27 on the horizontal part of the outer

branchial arch, and spotted like the preceding species. Coasts of

Europe, ascending rivers, and found in abundance in the Nile.

7. _C. menhaden._--The “Mossbanker,” common on the Atlantic coasts

of the United States. The economic value of this fish is surpassed

in America only by that of the Gadoids, and derived chiefly from its

use as bait for other fishes, and from the oil extracted from it, the

annual yield of the latter exceeding that of the whale (from American

Fisheries). The refuse of the oil factories supplies a material of much

value for artificial manures.

[See G. Brown Goode, “The Natural and Economical History of the

American Menhaden,” in U.S. Commission of Fish and Fisheries,

Part V., Washington, 1879, 8vo.]

8. _C. sapidissima._--The American Shad, abundant, and an important

food-fish on the Atlantic coasts of North America. Spawns in fresh

water.

9. _C. mattowocca._--The “Gaspereau” or “Ale-wife,” common on the

Atlantic coasts of North America, ascending into freshwater in early

spring, and spawning in ponds and lakes.

10. _C. pilchardus._--The “Pilchard” or the “Sardine,” equally

abundant in the British Channel, on the coast of Portugal, and in

the Mediterranean, and readily recognised by radiating ridges on the

operculum, descending towards the sub-operculum.

11. _C. sagax._--Representing the Pilchard in the Pacific, and found in

equally large shoals on the coasts of California, Chile, New Zealand,

and Japan.

12. _C. toli._--The subject of a very extensive fishery on the coast

of Sumatra for the sake of its roes, which are salted and exported to

China, the dried fish themselves being sent into the interior of the

island. The fish is called “Trubu” by the Malays, about 18 inches long,

and it is said that between fourteen and fifteen millions are caught

annually.

13. _C. scombrina._--The “Oil-Sardine” of the eastern coast of the

Indian Peninsula.

* * * * *

Other, but less important genera of Clupeoids with serrated

abdomen, are _Clupeoides_, _Pellonula_, _Clupeichthys_, _Pellona_,

_Pristigaster_, and _Chirocentrodon_ (these three last with very small

or without any ventral fins).

ALBULA.--Body oblong, moderately compressed; abdomen flat.

Scales of moderate size, adherent; lateral line distinct. Eyes

covered with a broad annular adipose membrane. Snout pointed,

the upper jaw projecting beyond the lower. Mouth inferior, of

moderate width, with villiform teeth; intermaxillary juxtaposed

to the upper anterior edge of the maxillary. Dorsal fin opposite

to the ventrals; anal fin shorter than dorsal. Gill-membranes

entirely separate, with numerous branchiostegals.

One species only (_A. conorhynchus_), ranging over all tropical

and sub-tropical seas, and very common in many localities near the

coasts. It grows to a length of from two to three feet, and is not

valued as food.

ELOPS.--Body rather elongate, moderately compressed; abdomen

flat. Scales small, adherent; lateral line distinct. A narrow

osseous lamella, attached to the mandibulary symphysis, covers

the part between the mandibles. Snout pointed; mouth wide,

anterior; intermaxillary short, maxillary forming the lateral

part of the mouth. Bands of villiform teeth in the jaws, on the

vomer, palatine and pterygoid bones, on the tongue, and on the

base of the skull. Dorsal fin opposite to ventrals; anal rather

shorter than dorsal. Gill-membranes entirely separate, with very

numerous branchiostegals.

Two species, of which one, _E. saurus_, is, like the preceding fish,

spread over all tropical and sub-tropical seas; it exceeds a length of

three feet, and is not esteemed as food.

[Illustration: Fig. 301.--Elops saurus.]

MEGALOPS.--Body oblong, compressed, abdomen flat. Scales large,

adherent; lateral line distinct. A narrow osseous lamella,

attached to the mandibulary symphysis, between the mandibles.

Snout obtusely conical; mouth anterior, lower jaw prominent;

intermaxillary short; maxillary forming the lateral part of

the mouth. Bands of villiform teeth in the jaws, on the vomer,

palatine and pterygoid bones, on the tongue and on the base

of the skull. Dorsal fin opposite to, or immediately behind,

the ventrals; anal rather larger than dorsal. Gill-membranes

entirely separate, with numerous branchiostegals. Pseudobranchiæ

none.

Two species, one belonging to the Indo-Pacific (_M. cyprinoides_),

the other to the Atlantic (_M. thrissoides_); they are the largest

fishes of this family, exceeding a length of five feet, and excellent

eating. Young specimens enter freely fresh waters.

CHANOS.--Body oblong, compressed; abdomen flat. Scales small,

striated, adherent; lateral line distinct. Snout depressed;

mouth small, anterior, transverse, the lower jaw with a small

symphysial tubercle. Intermaxillary in juxtaposition to the

upper anterior edge of maxillary. Teeth none. Dorsal fin

opposite to the ventrals; anal small, shorter than dorsal;

caudal deeply forked. Gill-membranes entirely united below, and

free from the isthmus. Branchiostegals four, long. An accessory

branchial organ in a cavity behind the gill-cavity proper.

Air-bladder divided by a constriction into an anterior and

posterior portion. Mucous membrane of the œsophagus raised in a

spiral fold. Intestine with many convolutions.

Two species from the Indo-Pacific, of which _Ch. salmoneus_ is

extremely common; it enters fresh waters, and exceeds a length of four

feet; its flesh is highly esteemed. The accessory branchial organ and

the skeleton have been described by _Müller_, “Bau und Grenzen der

Ganoiden,” p. 75; and by _Hyrtl_, “Denkschr. Ak. Wiss. Wien.” xxi.

1883, p. 1.

* * * * *

[Illustration: Fig. 302.--Chanos salmoneus.]

The remaining genera belonging to this family are _Spratelloides_,

_Dussumieria_, and _Etrumeus_, which together form a small group,

distinguished by an anterior and lateral mouth, by the upper jaw not

overlapping the lower, by a rounded abdomen, and by lacking the gular

plate of some of the preceding genera.

TWENTY-THIRD FAMILY--BATHYTHRISSIDÆ.

_Body oblong, with rounded abdomen, covered with cycloid scales;

head naked; barbels none. Margin of the upper jaw formed by the

intermaxillaries mesially, and by the maxillaries laterally. Opercular

apparatus complete. Adipose fin none; dorsal fin much elongate, many

rayed; anal fin short. Stomach with a blind sac; pyloric appendages

numerous. Gill-apparatus well developed; pseudobranchiæ; gill-openings

wide; an air-bladder. Ova very small; ovaries without duct._

One genus and species only (_Bathythrissa dorsalis_) from deep water

(350 fathoms) off the coast of Japan. This remarkable fish has the

appearance of a _Coregonus_, and attains to a length of two feet.

Nothing is known of its osteology, but possibly a fossil genus from the

Gyps of Montmartre; _Notæus_, which has also a long dorsal fin, may

prove to belong to the same family.

TWENTY-FOURTH FAMILY--CHIROCENTRIDÆ.

_Body covered with thin, deciduous scales; barbels none. Margin

of the upper jaw formed by the intermaxillaries mesially, and by

the maxillaries laterally, both bones being firmly united, in

juxtaposition. Opercular apparatus complete. Adipose fin none; the

dorsal fin belongs to the caudal portion of the vertebral column.

Stomach with a blind sac; intestine short, the mucous membrane

forming a spiral fold; pyloric appendages none. Pseudobranchiæ none;

air-bladder incompletely divided into cells; gill-opening wide._

One genus and species only (_Chirocentrus dorab_) is known, which

is common in the Indian Ocean, and attains to a length of about

three feet; it is not esteemed as food. Remains of fishes similar to

_Chirocentrus_ are found in the marl slates of Padang, in Sumatra.

TWENTY-FIFTH FAMILY--ALEPOCEPHALIDÆ.

_Body with or without scales; head naked; barbels none. Margin of the

upper jaw formed by the intermaxillaries and maxillaries, the former

being placed along the upper anterior edge of the latter. Opercular

apparatus complete. Adipose fin none; the dorsal fin belongs to the

caudal portion of the vertebral column. Stomach curved, without blind

sac; pyloric appendages in moderate number. Pseudobranchiæ; air-bladder

absent. Gill-openings very wide._

Before the voyage of the “Challenger” one species only of this

family was known, _Alepocephalus rostratus_, a rare fish from the

Mediterranean; now, four genera with seven species are known, and there

is no doubt that this family is one of the most characteristic, and

will prove to be one of the most generally distributed forms, of the

deep-sea. Their vertical range varies between 345 (_Xenodermichthys_)

and 2150 (_Bathytroctes_) fathoms. They approach the Salmonoids, but

lack invariably the adipose fin. Their dentition is very feeble; their

eye large; bones thin. Coloration black.

ALEPOCEPHALUS has thin cycloid scales; a mouth of moderate

width, and no teeth on the maxillary.

BATHYTROCTES has cycloid scales, a wide mouth, and teeth on the

maxillary as well as intermaxillary.

PLATYTROCTES has small keeled scales and no ventrals.

XENODERMICHTHYS with fine nodules instead of scales.

TWENTY-SIXTH FAMILY--NOTOPTERIDÆ.

_Head and body scaly; barbels none. Margin of the upper jaw formed

by the intermaxillaries mesially, and by the maxillaries laterally.

Opercular apparatus incomplete. Tail prolonged, tapering. Adipose fin

none. Dorsal short, belonging to the caudal portion of the vertebral

column; anal very long. Stomach without blind sac; two pyloric

appendages. Pseudo__branchiae none; air-bladder present, divided

in the interior. The ova fall into the cavity of the abdomen before

exclusion. On each side a parieto-mastoid cavity leading into the

interior of the skull._

One genus only (_Notopterus_) with five species which inhabit fresh

waters of the East Indies and West Africa. Well-preserved remains

of this genus occur in the marl slates of Padang, in Sumatra. Their

air-bladder is divided into several compartments, and terminates in two

horns anteriorly and posteriorly, the anterior horns being in direct

connection with the auditory organ.

TWENTY-SEVENTH FAMILY--HALOSAURIDÆ.

_Body covered with cycloid scales; head scaly; barbels none. Margin

of the upper jaw formed by the intermaxillaries mesially, and by the

maxillaries laterally. Opercular apparatus incomplete. Adipose fin

none. The short dorsal belongs to the abdominal part of the vertebral

column; anal very long. Stomach with a blind sac; intestine short;

pyloric appendages in moderate number. Pseudobranchiæ none. Air-bladder

large, simple; gill-openings wide. Ovaries closed._

The only genus belonging to this family was discovered by the Madeiran

ichthyologist Johnson, in 1863; but since then the naturalists of the

“Challenger” expedition have added four other species, showing that

this type is a deep-sea form and widely distributed; the specimens were

dredged in depths varying from 560 to 2750 fathoms.

TWENTY-EIGHTH FAMILY--HOPLOPLEURIDÆ.

_Body generally with four series of subtriangular scutes, and with

intermediate scale-like smaller ones. One (?) dorsal only; head long,

with the jaws produced._

_Extinct_; developed in the chalk and extending into tertiary

formations: _Dercetis_ (with the upper jaw longest), _Leptotrachelus_,

_Pelargorhynchus_, _Plinthophorus_, _Saurorhamphus_ (with the lower jaw

longest), _Eurypholis_; _Ischyrocephalus_ (?). The latter genus, from

cretaceous formations of Westphalia, is said to have two dorsal fins.

TWENTY-NINTH FAMILY--GYMNOTIDÆ.

_Head scaleless; barbels none. Body elongate, eel-shaped. Margin

of the upper jaw formed in the middle by the intermaxillaries, and

laterally by the maxillaries. Dorsal fin absent or reduced to an

adipose strip; caudal generally absent, the tail terminating in a

point. Anal fin exceedingly long. Ventrals none. Extremity of the

tapering tail capable of being reproduced. Vent situated at, or at a

short distance behind, the throat. Humeral arch attached to the skull.

Ribs well developed. Gill-openings rather narrow. Air-bladder present,

double. Stomach with a cæcal sac and pyloric appendages. Ovaries with

oviducts._

Eel-like freshwater fishes from Tropical America.

STERNARCHUS.--Tail terminating in a distinct small caudal fin.

Teeth small. A rudimentary dorsal fin is indicated by an adipose

band fitting into a groove on the back of the tail; it is easily

detached, so as to appear as a thong-like appendage fixed in

front. Branchiostegals four.

Eight species, some have the snout compressed and of moderate length,

like _St. Bonapartii_ from the River Amazons; others have it produced

into a long tube, as St. oxyrhynchus from the Essequibo.

RHAMPHICHTHYS.--Caudal fin none; teeth none; no trace of a

dorsal fin. No free orbital margin.

Six species, of which, again, some have a tubiform snout, whilst in the

others it is short.

STERNOPYGUS.--Caudal fin none; no trace of a dorsal fin. Both

jaws with small villiform teeth; similar teeth on each side of

the palate. Body scaly.

Four species, very common, and growing to a length of 30 inches.

CARAPUS.--Caudal fin none; no trace of a dorsal fin. A series of

conical teeth in each jaw. Anterior nostrils, wide in the upper

lip. Body scaly.

One species (_C. fasciatus_) extremely common, and found all over

tropical America, east of the Andes, from 18 to 24 inches long.

GYMNOTUS.--Caudal and dorsal fins absent; anal extending to the

end of the tail. Scales none. Teeth conical, in a single series.

Eyes exceedingly small.

The “Electric Eel” is the most powerful of electric fishes, growing to

a length of six feet, and extremely abundant in certain localities of

Brazil and the Guyanas. The electric organ consists of two pairs of

longitudinal bodies, situated immediately below the skin, above the

muscles; one pair on the back of the tail, and the other pair along

the anal fin. Each fasciculus is composed of flat partitions or septa,

with transverse divisions between them. The outer edge of the septa

appear in nearly parallel lines in the direction of the longitudinal

axis of the body, and consist of thin membranes, which are easily torn;

they serve the same purpose as the columns in the analogous organ

of the Torpedo, making the walls or abutments for the perpendicular

and transverse dissepiments, which are exceedingly numerous, and so

closely aggregated as to seem almost in contact. The minute prismatic

cells, intercepted between these two sorts of plates, contain a

gelatinous matter; the septa are about one-thirtieth of an inch from

each other, and one inch in length contains a series of 240 cells,

giving an enormous surface to the electric organs. The whole apparatus

is supplied with more than 200 nerves, which are the continuations of

the rami anteriores of the spinal nerves. In their course they give out

branches to the muscles of the back, and to the skin of the animal.

In the Gymnotus, as in the Torpedo, the nerves supplying the electric

organs are much larger than those bestowed on any part for the purposes

of sensation or movement.

The graphic description by Humboldt of the capture of Electric Eels

by horses driven into the water, which would receive the electric

discharges and thus exhaust the fishes, seems to rest either on the

imagination of some person who told it to the great traveller or on

some isolated incident. Recent travellers have not been able to verify

it even in the same parts of the country where the practice was said to

exist.

THIRTIETH FAMILY--SYMBRANCHIDÆ.

_Body elongate, naked or covered with minute scales; barbels none.

Margin of the upper jaw formed by the intermaxillaries only, the well

developed maxillaries lying behind and parallel to them. Paired fins

none. Vertical fins rudimentary, reduced to more or less distinct

cutaneous folds. Vent situated at a, great distance behind the head.

Ribs present. Gill-openings confluent into one slit situated on the

ventral surface. Air-bladder none. Stomach without cæcal sac or pyloric

appendages. Ovaries with oviducts._

The fishes of this family consist of freshwater-fishes from tropical

America and Asia, which, however, enter also brackish water; and of a

truly marine genus from Australia.

AMPHIPNOUS.--Vent in the posterior half of the body, which is

covered with minute scales longitudinally arranged.