respiratory apparatus. It has only three branchial arches, with
rudimentary branchial laminæ, and with very narrow slits between the
arches. To supplement this insufficient respiratory apparatus, a
lung-like sac is developed on each side of the body behind the head,
opening between the hyoid and first branchial arch. The interior of the
sac is abundantly provided with blood-vessels, the arterial coming from
the branchial arteries, whilst those issuing from it unite to form the
aorta. _A. cuchia_ approaches the Eels in having the humeral arch not
attached to the skull.
MONOPTERUS.--Vent in the posterior half of the body, which
is naked. Three branchial arches with rudimentary gills, but
without breathing sac.
One species (_M. javanicus_), which is extremely common in the East
Indian Archipelago and in the eastern parts of the Continent. Upwards
of three feet long.
SYMBRANCHUS.--Vent in the posterior half of the body, which is
naked. Four branchial arches with well developed gills.
Three species, of which one (_S. marmoratus_) is extremely common in
tropical America, and the other (_S. bengalensis_) not less so in the
East Indies.
CHILOBRANCHUS.--Vent in the anterior half of the length of
the body, which is naked. Vertical fins reduced to a simple
cutaneous fold, without rays.
A small fish (_Ch. dorsalis_) from North Western Australia and Tasmania.
THIRTY-FIRST FAMILY--MURÆNIDÆ.
_Body elongate, cylindrical or “band-shaped, naked or with
rudimentary scales. Vent situated at a great distance from the head.
Ventral fins none. Vertical fins, if present, confluent, or separated
by the projecting tip of the tail. Sides of the upper jaw formed by the
tooth-bearing maxillaries, the fore part by the intermaxillary, which
is more or less coalescent with the vomer and ethmoid. Humeral arch not
attached to the skull. Stomach with a blind sac; no pyloric appendages.
Organs of reproduction without efferent ducts._
The “Eels” are spread over almost all fresh waters and seas of the
temperate and tropical zones; some descend to the greatest depths
of the oceans. The young of some have a limited pelagic existence.
(_Leptocephali_, see p. 179.) At Monte Bolca fossil remains are very
numerous, belonging to recent genera, _Anguilla_, _Sphagebranchus_, and
_Ophichthys_; even larval Leptocephales have been preserved. _Anguilla_
has been found also in the chalk of Aix and Oeningen.
In the majority of the species the branchial openings in the pharynx
are wide slits (_Murænidæ platyschistæ_); in others, the true Murænæ,
(_Murænidæ engyschistæ_) they are narrow.
NEMICHTHYS.--Exceedingly elongate, band-shaped; tail tapering
into a point. Vent approximate to the pectorals, but the
abdominal cavity extending far behind the vent. Jaws produced
into a long slender bill, the upper part being formed by the
vomer and intermaxillaries. The inner surface of the bill
covered with small tooth-like asperities. Eye large. The
nostrils of each side are close together, in a hollow before the
eye. Gill-openings wide, nearly confluent. Pectoral and vertical
fins well developed.
This very singular type is a deep-sea form, occurring at depths of from
500 to 2500 fathoms. The two species known have hitherto been found in
the Atlantic only.
CYEMA.--This genus combines the form of the snout of
_Nemichthys_, with the soft and shorter body of a
_Leptocephalus_; but the gill-openings are very narrow and close
together on the abdominal surface. Vent in about the middle of
the length of the body; vertical fins well developed, confined
to, and surrounding, the tail. Pectoral fins well developed. Eye
very small.
Known from two specimens only, 4½ inches long, dredged in depths of
1500 and 1800 fathoms in the Pacific and Antarctic Oceans.
SACCOPHARYNX.--Deep-sea Congers, with the muscular system
very feebly developed, with the bones very thin, soft, and
wanting in inorganic matter. Head and gape enormous. Snout
very short, pointed, flexible, like an appendage overlapping
the gape. Maxillary and mandibulary bones very thin, slender,
arched, armed with one or two series of long, slender, curved,
widely set teeth, their points being directed inwards; palate
toothless. Gill-openings wide, at some distance from the head,
at the lower part of the sides; gills very narrow, free, and
exposed. Trunk of moderate length. Stomach distensible in
an extraordinary degree. Vent at the end of the trunk. Tail
band-like, exceedingly long, tapering in a very fine filament.
Pectoral small, present. Dorsal and anal fins rudimentary.
This is another extraordinary form of Deep-sea Eels; the muscular
system, except on the head, is very feebly developed; the bones are as
thin, soft, and wanting in inorganic matter, as in the _Trachypteridæ_.
This fish is known from three specimens only, which have been found
floating on the surface of the North Atlantic, with their stomachs much
distended, having swallowed some other fish, the weight of which many
times exceeded that of their destroyer. It attains to the length of
several feet.
SYNAPHOBRANCHUS.--Gill-openings ventral, united into a
longitudinal slit between the pectoral fins, separate
internally. Pectoral and vertical fins well developed. Nostrils
lateral, the anterior subtubular, the posterior round, before
the lower half of the eye. Cleft of the mouth very wide; teeth
small; body scaly. Stomach very distensible.
Deep-sea Congers, with well-developed muscular system, spread over
all oceans, and occurring in depths of from 345 to 2000 fathoms. Four
species are known. Probably attaining to the same length as the Conger.
ANGUILLA.--Small scales imbedded in the skin. Upper jaw not
projecting beyond the lower. Teeth small, forming bands.
Gill-openings narrow, at the base of the pectoral fins. The
dorsal fin commences at a considerable distance from the occiput.
Some twenty-five species of “Eels” are known from the freshwaters and
coasts of the temperate and tropical zones; none have been found in
South America or the west coast of North America and West Africa.
The following are the most noteworthy:--The common European species
(_A. anguilla_) is spread over Europe to 64° 30´ lat. N., and all
round the Mediterranean area, but is not found either in the Danube
or in the Black and Caspian Seas; it extends across the Atlantic to
North America. The form of the snout varies much, and some naturalists
have believed that specimens with a broad and obtuse snout were
specifically distinct from those with pointed snout. However, every
degree of breadth of the snout may be observed; and a much safer
way of recognizing this species, and distinguishing it from other
European Eels, is the forward position of the dorsal fin; the distance
between the commencement of the dorsal and anal fins being as long as,
or somewhat longer than, the head. Eels grow generally to a length
of about three feet, but the capture of much larger examples is on
record. Their mode of propagation is still unknown. So much only is
certain that they do not spawn in fresh water, that many full-grown
individuals, but not all, descend rivers during the winter months, and
that some of them at least must spawn in brackish water or in deep
water in the sea; for in the course of the summer young individuals
from three to five inches long ascend rivers in incredible numbers,
overcoming all obstacles, ascending vertical walls or floodgates,
entering every larger and smaller tributary, and making their way
even over terra firma to waters shut off from all communication
with rivers. Such immigrations have been long known by the name of
“_Eel-fairs_.” The majority of the Eels which migrate to the sea
appear to return to fresh water, but not in a body, but irregularly,
and throughout the warmer part of the year. No naturalist has ever
observed these fishes in the act of spawning, or found mature ova; and
the organs of reproduction of individuals caught in fresh water are
so little developed and so much alike, that the female organ can be
distinguished from the male only with the aid of a microscope.
The second species found in Great Britain, on the coasts of Europe
generally, in China, New Zealand, and the West Indies, is (_A.
latirostris_) the “Grig” or “Glut,” which prefers the neighbourhood of
the sea to distant inland-waters, and in which the dorsal fin begins
farther backwards, the distance between the commencement of the dorsal
and anal fins being shorter than the head; its snout seems to be always
broad. On the American side of the Atlantic other species, beside _A.
anguilla_ are found in abundance: _A. bostoniensis_, _A. texana_.
The largest Eels occur in lakes of the islands of the Indo-Pacific,
and they play a conspicuous part in the mythology of the South-Sea
Islanders and Maories; individuals of from eight to ten feet in length
have been seen, and referred to several species, as _A. mauritiana_,
_fidjiensis_, _obscura_, _aneitensis_, etc.
CONGER.--Scaleless. Cleft of the mouth wide, extending at least
to below the middle of the eye. Maxillary and mandibulary
teeth arranged in series, one of which contains teeth of equal
size, and so closely set as to form a cutting edge. No canine
teeth. Vomerine band of teeth short. Pectoral and vertical fins
well developed, the dorsal commencing behind the root of the
pectoral. Gill-openings large, approximate to the abdomen. The
posterior nostril opposite to the upper or middle part of the
orbit, the anterior in a tube. Eyes well developed.
The “Congers” are marine Eels; the best known species (_C. conger_)
seems to be almost cosmopolitan, and is plentiful all round Europe, at
St. Helena, in Japan, and Tasmania. It attains to a length of eight
feet, and thrives and grows rapidly even in confinement, which is
not the case with the freshwater Eel. Three other species are known,
of which _C. marginatus_ from the Indian Ocean, is the most common.
_Leptocephalus morrisii_ is an abnormal larval condition of the Conger.
Genera allied to _Conger_ are _Poeciloconger_, _Congromurcæna_,
_Uroconger_, and _Heteroconger_.
MURÆNESOX.--Scaleless. Snout produced. Jaws with several series
of small closely set teeth, anteriorly with canines; vomer with
several long series of teeth, the middle of which is formed
by large conical or compressed teeth. Gill-openings wide,
approximate to the abdomen. Pectoral and vertical fins well
developed, the dorsal beginning above the gill-opening. Two
pairs of nostrils, the posterior opposite to the upper part or
middle of the eye.
Four species from tropical seas, _M. cinereus_ being very common in the
Indian Ocean, and attaining to a length of six feet.
NETTASTOMA.--Scaleless. Snout much produced, depressed. Jaws
and vomer with bands of card-like teeth, those along the median
line of the vomer being somewhat the larger. Vertical fins well
developed; pectorals none. Gill-openings of moderate width,
open. Nostrils on the upper surface of the head, valvular; the
anterior near to the end of the snout, the posterior above the
anterior angle of the eye.
This genus lives at some depth, the Japanese species (_N. parviceps_)
having been obtained at 345 fathoms. _N. melanurum_ from the
Mediterranean, seems to inhabit a similar depth. _Hyoprorus_ is its
Leptocephalid form.
Genera allied to _Murcænesox_ are _Saurenchelys_, _Oxyconger_,
_Hoplunnis_, and _Neoconger_; in all these the nostrils have a
superior or lateral position. In other genera the nostrils perforate
the upper lip, as in _Myrus_, _Myrophis_, _Paramyrus_, _Chilorhinus_,
_Murænichthys_, and _Ophichthys_, the last genus deserving of
particular mention on account of its great range and common occurrence.
OPHICHTHYS.--Nostrils labial; extremity of the tail free, not
surrounded by a fin.
More than eighty species are known, many of which are abundant on the
coasts of the tropical and sub-tropical zones. They do not attain to
a large size, but many must be extremely voracious and destructive to
other fishes, if we draw an inference from the formidable dentition
with which their jaws and palate is armed. Other species have much
more feeble, and some even obtuse teeth, better adapted for seizing
Crustaceans than vigorous and slippery fishes. Some have rudimentary
pectoral fins or lack them altogether. Many are highly ornamented with
bands or spots, the coloration being apparently very constant in the
several species.
[Illustration: Fig. 303.--Ophichthys crocodilinus, from the
Indo-Pacific.]
MORINGUA.--Body scaleless, cylindrical, with the trunk much
longer than the tail. Pectorals none or small; vertical fins
but little developed, limited to the tail. Posterior nostrils
in front of the small eye. Cleft of the mouth narrow; teeth
uniserial. Heart placed far behind the branchiæ. Gill-openings
rather narrow, inferior.
Six species from freshwaters, brackish water, and the coasts of India
to the Fiji Islands.
MURÆNA.--Scaleless. Teeth well developed. Gill-openings and
clefts between the branchial arches narrow. Pectoral fins none;
dorsal and anal fins well developed. Two nostrils on each side
of the upper surface of the snout; the posterior a narrow round
foramen, with or without tube; the anterior in a tube.
[Illustration: Fig. 304.--Head of a Muræna.]
[Illustration: Fig. 305.--Muræna pavonina, from Southern Seas.]
The Murænas are as abundantly represented in the tropical and
sub-tropical zones, and have nearly the same range, as _Ophichthys_.
The number of species known exceeds eighty. The majority are armed
with formidable pointed teeth, well suited for seizing other fish on
which they prey. Large specimens thus armed readily attack persons in
and out of the water; and as some species attain a length of some six
or eight feet, they are justly feared by fishermen. The minority of
species have obtuse and molar-like teeth, their food consisting chiefly
of Crustaceans and other hard-shelled animals. Most of the Murænas
are beautifully coloured and spotted, some in a regular and constant
manner, whilst in others the pattern varies in a most irregular
fashion: they have quite the appearance of snakes. The Muræna of
the Ancient Romans is _Muræna helena_, which is not confined to the
Mediterranean, but also found in the Indian Ocean and on the coast of
Australia. Its skin is of a rich brown, beautifully marked with large
yellowish spots, each of which contains smaller brown spots.
[Illustration: Fig. 306.--Muræna picta, from the Indo-Pacific.]
_Gymnomuræna_ differs from _Muræna_ in having the fins reduced to a
short rudiment near the end of the tail. Six species are known growing
to a length of eight feet.
[Illustration: Fig. 307.--Gymnomuræna vittata, from Cuba.]
_Myroconger_ and _Enchelycore_ belong to the same sub-family as
_Muræna_, but the former is provided with pectoral fins, and in the
latter the posterior nostril is a long slit, and not round as in the
other genera.
FIFTH ORDER--LOPHOBRANCHII.
_The gills are not laminated, but composed of small rounded lobes
attached to the branchial arches. Gill-cover reduced to a large simple
plate. Air-bladder simple, without pneumatic duct. A dermal skeleton
composed of numerous pieces arranged in segments, replaces more or less
soft integuments. Muscular system not much developed. Snout prolonged.
Mouth terminal, small, toothless, formed as in Acanthopterygians._
[Illustration: Fig. 308.--Gills of Hippocampus abdominalis.]
FIRST FAMILY--SOLENOSTOMIDÆ.
_Gill-openings wide. Two dorsal fins, the rays of the anterior not
articulated. All the other fins well developed._
One living genus only is known, which was preceded in the tertiary
epoch by _Solenorhynchus_ (Monte Postale).
SOLENOSTOMA.--Snout produced into a long tube. Body compressed,
with very short tail. All parts covered with thin skin, below
which there is a dermal skeleton formed by large star-like
ossifications. The soft dorsal and anal fins on elevated
bases; caudal fin long. Ventral fins inserted opposite to the
anterior dorsal, close together, seven-rayed; they are free in
the male, but in the female their inner side coalesces with the
integuments of the body, a large pouch for the reception of
the eggs being formed thereby. Air-bladder and pseudobranchiæ
absent. Branchiostegals four, very thin. Intestinal tract very
simple, with a stomachic dilatation, without pyloric appendages.
Ova very small.
The dermal skeleton of this singular type is formed by star-like
ossifications, four in each horizontal and vertical series on the side
of the fore part of the trunk; each consists of four or three radiating
branches by which it joins the neighbouring bones; on the hind part
of the trunk and tail the series are diminished to two. The dorsal
and abdominal profiles in front of the fins are protected by similar
bones. The vertebral column is composed of eighteen abdominal and
fifteen caudal vertebræ, the vertebræ gradually decreasing in length
backwards, so that the shortness of the tail is caused not only by
the smaller number of vertebræ, but also by their much lesser length.
Neural and hæmal spines are developed. The pelvis consists of two pairs
of cartilaginous laminæ, the convex margin of the anterior fitting
into an angle of a dermal bone which separates the pelvis from the
well-ossified humeral arch.
The singular provision for the retention and protection of the eggs has
been described above (p. 162, figs. 73 and 74), and we have only to
repeat here that it is the female which takes care of the progeny, and
not the male as in the following family. Two or three small species are
known from the Indian Ocean; they are beautifully marked, especially
the male, which also appears to be of smaller size in this genus than
the female.
SECOND FAMILY--SYNGNATHIDÆ.
_Gill-openings reduced to a very small opening near the upper
posterior angle of the gill-cover. One soft dorsal fin; no ventrals,
and, sometimes, one or more of the other fins are also absent._
Small marine fishes, which are abundant on such parts of the coasts
of the tropical and temperate zones as offer by their vegetation
shelter to these defenceless creatures. They are bad swimmers (the
dorsal fin being the principal organ of locomotion), and frequently
and resistlessly carried by currents into the open ocean or to distant
coasts. All enter brackish water, some fresh water. The strata of Monte
Bolca and Licata (Sicily) have, yielded evidence of their existence in
the tertiary epochs; beside species of _Siphonostoma_ and _Syngnathus_
(_Pseudosyngnathus_), remains of an extinct genus, _Calamostoma_,
allied to _Hippocampus_, but with a distinct caudal fin, have been
found. On their propagation see p. 163, Fig. 76.
A. SYNGNATHINA.--The tail is not prehensile, and generally
provided with a caudal fin.--_Pipe-Fishes._
SIPHONOSTOMA.--Body with distinct ridges, the upper caudal
ridge continuous with the lateral line, but not with the dorsal
ridge of the trunk. Pectoral and caudal fins well developed;
dorsal fin of moderate length, opposite to the vent. Humeral
bones movable, not united into a “breast-ring.” Males with an
egg-pouch on the tail, the eggs being covered by cutaneous folds.
Two species, of which _S. typhle_ is common on the British, and
generally distributed on the European coasts.
SYNGNATHUS.--Body with the ridges more or less distinct, the
dorsal ridge of the trunk not being continuous with that of the
tail. Pectoral fins well developed; caudal present. Dorsal fin
opposite or near to the vent. Humeral bones firmly united into
the breast-ring. Egg-pouch as in _Siphonostoma_.
The distribution of this genus nearly coincides with that of the
family, some fifty species being known. _S. acus_, the great Pipe-fish
(see Fig. 75, p. 163), is one of the most common European fishes,
extending across the Atlantic and southwards to the Cape of Good
Hope; it attains a length of 18 inches. Another very common species,
frequently met at sea, and spread over nearly all the tropical and
sub-tropical seas, is _S. pelagicus_, agreeably marked with alternate
brown and silvery cross-bars.
DORYICHTHYS.--Body with the ridges well developed. Pectoral and
caudal fins present. Dorsal fin long or of moderate length,
opposite to the vent. Humeral bones firmly united. Males with
the lower ridges of the abdomen dilated, the dilated parts
forming a broad groove for the reception of the ova.
In these Pipe-fishes the ova are not received in a completely closed
pouch, but glued on to the surface of the abdomen. Twenty species from
tropical seas.
NEROPHIS.--Body smooth, rounded, with scarcely any of the ridges
distinct. Pectoral fin none, caudal absent or rudimentary, the
tail tapering into a point. Dorsal fin of moderate length,
opposite to the vent. The ova are attached to the soft
integument of the abdomen of the male, and are not covered by
lateral folds of the skin.
Seven species from the European seas and the Atlantic. _N. æquoreus_
(Ocean Pipe-fish), _N. ophidion_ (Straight-nosed Pipe-fish), and _N.
lumbriciformis_ (Little Pipe-fish), are common on the British coasts.
PROTOCAMPUS.--The whole dermal skeleton is covered with skin.
A broad cutaneous fold runs along the back in front and behind
the dorsal; a similar fold along the abdomen. Pectoral fin none;
caudal very small.
The single species of this remarkable genus, _P. hymenolomus_, occurs
in the Falkland Islands. It may be regarded as an embryonal form of
_Nerophis_, the median skin-folds being evidently remains of the fringe
which surrounds the body of the embryo.
The other genera belonging to this group are, _Icthyocampus_,
_Nannocampus_, _Urocampus_, _Leptoichthys_, _Coelonotus_, and
_Stigmatophora_.
HIPPOCAMPINA.--The tail is prehensile, and invariably without
caudal fin.--_Sea-horses._
GASTROTOKEUS.--Body depressed, the lateral line running along
the margin of the abdomen. Shields smooth. Tail shorter than the
body. Pectoral fins. No pouch is developed for the ova, which
are imbedded in the soft integument of the abdomen of the male.
_Gastrotokeus biaculeatus_, very common in the Indian Ocean to the
coasts of Australia.
SOLENOGNATHUS.--Body compressed, deeper than broad. Shields
hard, rugose, with round or oval interannular plates; and
without elongate processes. Tail shorter than the body. Pectoral
fins.
Three species, from the Chinese and Australian Seas; they are the
largest of Lophobranchs, _S. hardwickii_, attaining to a length of
nearly two feet.
[Illustration: Fig. 309.--Phyllopteryx eques.]
PHYLLOPTERYX.--Body compressed, or as broad as deep. Shields
smooth, but some or all of them are provided with prominent
spines or processes on the edges of the body; some of the
processes with cutaneous filaments. A pair of spines on the
upper side of the snout and above the orbit. Tail about as
long as the body. Pectoral fins. The ova are imbedded in soft
membrane on the lower side of the tail, without a pouch being
developed.
Three species from the coasts of Australia. The protective resemblances
with which many Lophobranchs are furnished, attain to the highest
degree of development in the fishes of this genus. Not only their
colour closely assimilates that of the particular kind of seaweed which
they frequent, but the appendages of their spines seem to be merely
part of the fucus to which they are attached. They attain a length of
12 inches.
HIPPOCAMPUS.--Trunk compressed, more or less elevated. Shields
with more or less prominent tubercles or spines. Occiput
compressed into a crest, terminating at its supero-posterior
corner in a prominent knob (coronet). Pectoral fins. The males
carry the eggs in a sac at the base of the tail, opening near
the vent.
A singular resemblance of the head and fore part of the body to that
of a horse, has given to these fishes the name of “Sea-horses.” They
are abundant between and near the tropics, becoming scarcer in higher
latitudes. Some twenty species are known, some of which have a wide
geographical range, as they are often carried to great distances with
floating objects to which they happen to be attached.--_Acentronura_ is
a genus closely allied to _Hippocampus_.
SIXTH ORDER--PLECTOGNATHI.
_Teleosteous fishes with rough scales, or with ossifications of the
cutis in the form of scutes or spines; skin sometimes entirely naked.
Skeleton incompletely ossified, with the vertebræ in small number.
Gills pectinate; a narrow gill-opening in front of the pectoral fins.
Mouth narrow; the bones of the upper jaw generally firmly united. A
soft dorsal fin, belonging to the caudal portion of the vertebral
column, opposite to the anal; sometimes elements of a spinous dorsal
besides. Ventral fin none, or reduced to spines. Air-bladder without
pneumatic duct._
FIRST FAMILY--SCLERODERMI.
_Snout somewhat produced; jaws armed with distinct teeth in small
number. Skin with scutes or rough. The elements of a spinous dorsal and
ventral fins generally present._
Marine fishes of moderate or small size, very common in the tropical
zone, but scarcer in higher latitudes. They have been found in three
localities of tertiary strata, viz., at Monte Bolca, where a species of
_Ostracion_ occurs, and in the Schists of Glaris, from which two genera
have been described, _Acanthoderma_ and _Acanthopleurus_, closely
allied to _Balistes_ and _Triacanthus_. _Glyptocephalus_ from the Isle
of Sheppey has the skull of a Balistes, but its body is covered with
tubercles arranged in regular series. The Scleroderms may be divided
into three very natural groups:--
A. TRIACANTHINA.--The skin is covered with small, rough,
scale-like scutes. A spinous dorsal fin with from four to six
spines. A pair of strong, movable ventral spines, joined to the
pelvic bone.
To this group belong the genera _Triacanthodes_, _Hollardia_, and
_Triacanthus_, represented by five species, of which _Triacanthus
brevirostris_ from the Indian Ocean is the most common.
B. BALISTINA.--Body compressed, covered with movable scutes or
rough. Spinous dorsal reduced to one, two, or three spines.
Ventral fins reduced to a single pelvic prominence, or entirely
absent.
To this group belong the genera _Balistes_, _Monacanthus_, and
_Anacanthus_, the last genus being distinguished by a barbel at the
lower jaw.
[Illustration: Fig. 310.--Balistes vidua.]
_Balistes_, or the “File-fishes” proper, inhabit the tropical and
sub-tropical seas; shoals of young are not rarely met with in
mid-ocean. Some thirty species are known, many attaining a length
exceeding two feet; but the majority are much smaller, and frequently
beautifully and symmetrically marked. Both jaws are armed with eight
strong incisor-like and obliquely truncated teeth, by which these
fishes are enabled to break off pieces of corals on which they feed,
or to chisel a hole into the hard shell of Mollusca, in order to
extract the soft parts. They destroy an immense number of Mollusks,
thus becoming most injurious to the pearl-fisheries. The first of their
three dorsal spines is very strong, roughened in front like a file,
and hollowed out behind to receive the second much smaller spine,
which, besides, has a projection in front, at its base, fitting into
a notch of the first. Thus these two spines can only be raised or
depressed simultaneously, and the first cannot be forced down, unless
the second has been previously depressed. The latter has been compared
to a trigger, hence a second name, “Trigger-fish,” has been given to
these fishes. Some species are armed with a series of short spines or
tubercles on each side of the tail. Two species (_B. maculatus_ and _B.
capriscus_), common in the Atlantic, sometimes wander to the British
coasts.
The _Monacanthus_ are similarly distributed as the _Balistes_, and
still more abundant, some fifty species being known. Their dentition
is very similar, but they possess one dorsal spine only, and their
rough scales are so small as to give a velvety appearance to the skin
(Figs. 17 and 18, p. 48). Adult males of some of the species possess a
peculiar armature on each side of the tail, which in females is much
less developed or entirely absent. This armature may consist either in
simple spines arranged in rows, or in the development of the minute
spines of the scales into long stiff bristles, so that the patch on
each side of the tail looks like a brush.
C. OSTRACIONTINA.--The integuments of the body form a hard
continuous carapace, consisting of hexagonal scutes juxtaposed
in mosaic-fashion. A spinous dorsal and ventral fins are absent;
but sometimes indicated by protuberances.
The “Coffer-fishes” (_Ostracion_) are too well known to require a
lengthened description. Only the snout, the bases of the fins, and the
hind part of the tail are covered with soft skin, so as to admit of
free action of the muscles moving these parts. The mouth is small, the
maxillary and intermaxillary bones coalescent, each jaw being armed
with a single series of small slender teeth. The short dorsal fin is
opposite to the equally short anal. The vertebral column consists of
fourteen vertebræ only, of which the five last are extremely short,
the anterior elongate. Ribs none. The carapaces of some species are
three-ridged, of others four- and five-ridged, of some provided with
long spines. Twenty-two species from tropical and sub-tropical seas are
known.
SECOND FAMILY--GYMNODONTES.
_Body more or less shortened. The bones of the upper and lower
jaw are confluent, forming a beak with a trenchant edge, without
teeth, with or without median suture. A soft dorsal, caudal and anal
are developed, approximate. No spinous dorsal. Pectoral fins; no
ventrals._
Marine fishes of moderate or small size from tropical and sub-tropical
seas. A few species live in fresh water. Fossil remains of
_Diodon_ are not scarce at Monte Bolca and Licata; a distinct
genus, _Enneodon_, has been described from Monte Postale. The
Gymnodonts may be divided into three groups:
A. TRIODONTINA.--Tail rather long, with a separate caudal fin.
Abdomen dilatable into a very large, compressed, pendent sac,
the lower part of which is merely a flap of skin, into which the
air does not penetrate, the sac being capable of being expanded
by the very long pelvic bone. The upper jaw divided by a median
suture, the lower simple.
A single genus and species (_Triodon bursarius_) from the Indian
Ocean.
B. TETRODONTINA.--Tail and caudal fin distinct. Part of the
œsophagus much distensible, and capable of being filled with
air. No pelvic bone.
“Globe-fishes” have a short, thick, cylindrical body, with well
developed fins. It is covered with thick scaleless skin, in which,
however, spines are imbedded of various sizes. The spines are very
small, and but partially distributed over the body in some species,
whilst in others they are very large, and occupy equally every part
of the body. These fishes have the power of inflating their body by
filling their distensible œsophagus with air, and thus assume a more or
less globular form. The skin is, then, stretched to its utmost extent,
and the spines protrude and form a more or less formidable defensive
armour, as in a hedgehog; therefore they are frequently called
“Sea-hedgehogs.” A fish thus blown out turns over and floats belly
upwards, driving before the wind and waves. However, it is probable
that the spines are a protection not only when the fish is on the
surface and able to take in air, but also when it is under water. Some
Diodonts, at any rate, are able to erect the spines about the head by
means of cutaneous muscles; and, perhaps, all fill their stomach with
water instead of air, for the same purpose and with the same effect. In
some Diodonts the spines are fixed, erect, not movable. The Gymnodonts
generally, when taken, produce a sound, doubtless by the expulsion
of air from the œsophagus. Their vertebral column consists of a small
number of vertebræ, from 20 to 29, and their spinal chord is extremely
short. All these fishes have a bad reputation, and they are never
eaten; indeed, some of them are highly poisonous, and have caused long
continued illness and death. Singularly, the poisonous properties of
these fishes vary much as regards intensity, only certain individuals
of a species, or individuals from a certain locality, or caught at a
certain time of the year, being dangerous. Therefore it is probable
that they acquire their poisonous quality from their food, which
consists in corals and hard-shelled Mollusks and Crustaceans. Their
sharp beaks, with broad masticating posterior surface, are admirably
adapted for breaking off branchlets of coral-stocks, and for crushing
hard substances.
[Illustration: Fig. 311.--Jaws of Tetrodon.]
[Illustration: Fig. 312.--Tetrodon margaritatus.]
TETRODON (including _Xenopterus_).--Both the upper and lower
jaws are divided into two by a mesial suture.
Extremely numerous in tropical and sub-tropical zones, more than
sixty species being known. In some of the species the dermal
spines are extremely small, and may be absent altogether. Many are
highly ornamented with spots or bands. A few species live in large
rivers--thus _T. psittacus_ from Brazil; _T. fahaka_, a fish well
known to travellers on the Nile, and likewise abundant in West African
rivers; _T. fluvi__atilis_ from brackish water and rivers of the East
Indies. The species figured is one of the smallest, about six inches
long, and common in the Indo-Pacific.
DIODON.--Jaws without mesial suture, so that there is only one
undivided dental plate above and one below.
In these fishes, as well as in some closely allied genera, the dermal
spines are much more developed than in the Tetrodonts; in some the
spines are erectile, as in _Diodon_, _Atopomycterus_, _Trichodiodon_,
and _Trichocyclus_; in others they are stiff and immovable, as in
_Chilomycterus_ and _Dicotylichthys_. Seventeen species are known, of
which _Diodon hystrix_ is the most common as it is the largest, growing
to a length of two feet. It is spread over the Tropical Atlantic as
well as Indo-Pacific, as is also a smaller, but almost equally common
species, _Diodon maculatus_.
[Illustration: Fig. 313.--Diodon maculatus.]
[Illustration: Fig. 314.--Diodon maculatus, inflated.]
C. MOLINA.--Body compressed, very short; tail extremely short,
truncate. Vertical fins confluent. No pelvic bone.
The “Sun-fishes” (_Orthagoriscus_) are pelagic fishes, found in every
part of the oceans within the tropical and temperate zones. The
singular shape of their body and the remarkable changes which they
undergo with age, have been noticed above (p. 175, Figs. 93, 94).
Their jaws are undivided in the middle, comparatively feeble, but well
adapted for masticating their food, which consists of small pelagic
Crustaceans. Two species are known. The common Sun-fish, _O. mola_,
which attains to a very large size, measuring seven or eight feet, and
weighing as many hundredweights. It has a rough, minutely granulated
skin. It frequently approaches the southern coasts of England and the
coasts of Ireland, and is seen basking in calm weather on the surface.
The second species, _O. truncatus_, is distinguished by its smooth,
tessellated skin, and one of the scarcest fishes in collections. The
shortness of the vertebral column of the Sun-fishes, in which the
number of caudal vertebra is reduced to seven, the total number being
seventeen, and the still more reduced length of the spinal chord have
been noticed above (p. 96).
THIRD SUB-CLASS--CYCLOSTOMATA.
_Skeleton cartilaginous and notochordal, without ribs and without
real jaws. Skull not separate from the vertebral column. No limbs.
Gills in the form of fixed sacs, without branchial arches, six or seven
in number on each side. One nasal aperture only. Heart without bulbus
arteriosus. Mouth anterior, surrounded by a circular or subcircular
lip, suctorial. Alimentary canal straight, simple, without coecal
appendages, pancreas or spleen. Generative outlet peritoneal. Vertical
fins rayed._
The Cyclostomes are most probably a very ancient type. Unfortunately
the organs of these creatures are too soft to be preserved, with the
exception of the horny denticles with which the mouth of some of them
is armed. And, indeed, dental plates, which are very similar to those
of _Myxine_, are not uncommon in certain strata of Devonian and
Silurian age (see p. 193). The fishes belonging to this sub-class may
be divided into two families--
FIRST FAMILY--PETROMYZONTIDÆ.
_Body eel-shaped, naked. Subject to a metamorphosis; in the perfect
stage with a suctorial mouth armed with teeth, simple or multicuspid,
horny, sitting on a soft papilla. Maxillary, mandibulary, lingual, and
suctorial teeth may be distinguished. Eyes present (in mature animals).
External nasal aperture in the middle of the upper side of the head.
The nasal duct terminates without perforating the palate. Seven
branchial sacs and apertures on each side behind the head; the inner
branchial ducts terminate in a separate common tube. Intestine with a
spiral valve. Eggs small. The larvæ without teeth, and with a single
continuous vertical fin._
“Lampreys” are found in the rivers and on the coasts of the temperate
regions of the northern and southern hemispheres. Their habits are but
incompletely known, but so much is certain that at least some of them
ascend rivers periodically, for the purpose of spawning, and that the
young pass several years in rivers, whilst they undergo a metamorphosis
(see p. 170). They feed on other fishes, to which they suck themselves
fast, scraping off the flesh with their teeth. Whilst thus engaged they
are carried about by their victim; Salmon have been captured in the
middle course of the Rhine with the Marine Lamprey attached to them.
[Illustration: Fig. 315.--Mouth of Larva of Petromyzon
branchialis.]
[Illustration: Fig. 316.--Mouth of Petromyzon fluviatilis.
_mx_, Maxillary tooth; _md_, Mandibulary tooth;
_l_, Lingual tooth; _s_, Suctorial teeth.]
PETROMYZON.--Dorsal fins two, the posterior continuous with the
caudal. The maxillary dentition consists of two teeth placed
close together, or of a transverse bicuspid ridge; lingual teeth
serrated.
The Lampreys belonging to this genus are found in the northern
hemisphere only; the British species are the Sea-Lamprey (_P.
marinus_), exceeding a length of three feet, and not uncommon on the
European and North American coasts; the River-Lamprey or Lampern (_P.
fluviatilis_), ascending in large numbers the rivers of Europe, North
America, and Japan, and scarcely attaining a length of two feet; the
“Pride” or “Sand-Piper” or Small Lampern (_P. branchialis_), scarcely
twelve inches long, the larva of which has been long known under the
name of _Ammocoetes_.
_Ichthyomyzon_ from the western coasts of North America is said to have
a tricuspid maxillary tooth.
MORDACIA.--Dorsal fins two, the posterior continuous with the
caudal. The maxillary dentition consists of two triangular
groups, each with three conical acute cusps; two pairs of
serrated lingual teeth.
[Illustration: Fig. 317.--Mouth of Mordacia mordax, closed and
opened.]
A Lamprey _(M. mordax_) from the coasts of Chile and Tasmania. This
fish seems to be provided sometimes with a gular sac, like the
following.[47]
[Illustration: Fig. 318.--Mordacia mordax.]
GEOTRIA.--Dorsal fins two, the posterior separate from the
caudal. Maxillary lamina with four sharp flat lobes; a pair of
long pointed lingual teeth.
Two species, one from Chile and one from South Australia. They grow
to a length of two feet, and in some specimens the skin of the throat
is much expanded, forming a large pouch. Its physiological function
is not known. The cavity is in the subcutaneous cellular tissue, and
does not communicate with the buccal or branchial cavities. Probably
it is developed with age, and absent in young individuals. In all
the localities in which these Extra-european Lampreys are found,
_Ammocoetes_ forms occur, so that there is little doubt that they
undergo a similar metamorphosis as _P. branchialis_.
SECOND FAMILY--MYXINIDÆ.
_Body eel-shaped, naked. The single nasal aperture is above the
mouth, quite at the extremity of the head, which is provided with four
pairs of barbels. Mouth without lips. Nasal duct without cartilaginous
rings, penetrating the palate. One median tooth on the palate, and
two comb-like series of teeth on the tongue_ (see Fig. 101).
_Branchial apertures at a great distance from the head; the inner
branchial ducts lead into the œsophagus. A series of mucous sacs along
each side of the abdomen. Intestine without spiral valve. Eggs large,
with a horny case provided with threads for adhesion._
[Illustration: Fig. 319.--Ovum of Myxine glutinosa, enlarged.]
The fishes of this family are known by the names of “Hag-Fish,”
“Glutinous Hag,” or “Borer;” they are marine fishes with a similar
distribution as the Gadidæ, being most plentiful in the higher
latitudes of the temperate zones of the northern and southern
hemispheres. They are frequently found buried in the abdominal cavity
of other fishes, especially Gadoids, into which they penetrate to feed
on their flesh. They secrete a thick glutinous slime in incredible
quantities, and are therefore considered by fishermen a great nuisance,
seriously damaging the fisheries and interfering with the fishing in
localities where they abound. _Myxine_ descends to a depth of
345 fathoms, and is generally met with in the Norwegian Fjords at 70
fathoms, sometimes in great abundance.
MYXINE.--One external branchial aperture only on each side of
the abdomen, leading by six ducts to six branchial sacs.
Three species from the North Atlantic, Japan, and Magelhæn’s Straits.
[Illustration: Fig. 320.--Myxine australis. A, Lower aspect
of head; _a_, Nasal aperture; _b_, Mouth; _g_,
Branchial aperture; _v_, Vent.]
BDELLOSTOMA.--Six or more external branchial apertures on each
side, each leading by a separate duct to a branchial sac.
Two species from the South Pacific.
FOURTH SUB-CLASS--LEPTOCARDII.
_Skeleton membrano-cartilaginous and notochordal, ribless. No brain.
Pulsating sinuses in place of a heart. Blood colourless. Respiratory
cavity confluent with the abdominal cavity; branchial clefts in great
number, the water being expelled by an opening in front of the vent.
Jaws none._
This sub-class is represented by a single family (_Cirrostomi_)
and by a single genus (_Branchiostoma_);[48] it is the lowest in
the scale of fishes, and lacks so many characteristics, not only of
this class, but of the vertebrata generally, that Hæckel, with good
reason, separates it into a separate class, that of _Acrania_. The
various parts of its organisation have been duly noticed in the first
part of this work.
The “Lancelet” (_Branchiostoma lanceolatum_, see Fig. 28, p. 63),
seems to be almost cosmopolitan within the temperate and tropical
zones. Its small size, its transparency, and the rapidity with which it
is able to bury itself in the sand, are the causes why it escapes so
readily observation, even at localities where it is known to be common.
Shallow, sandy parts of the coasts seem to be the places on which it
may be looked for. It has been found on many localities of the British,
and generally European coasts, in North America, the West Indies,
Brazil, Peru, Tasmania, Australia, and Borneo. It rarely exceeds
a length of three inches. A smaller species, in which the dorsal
fringe is distinctly higher and rayed, and in which the caudal fringe
is absent, has been described under the name of _Epigionichthys
pulchellus_; it was found in Moreton Bay.
APPENDIX.
DIRECTIONS FOR COLLECTING AND PRESERVING FISHES.
Whenever practicable fishes ought to be preserved in spirits.
To insure success in preserving specimens the best and strongest
spirits should be procured, which, if necessary, can be reduced to
the strength required during the journey with water or weaker spirit.
Travellers frequently have great difficulties in procuring spirits
during their journey, and therefore it is advisable, especially during
sea voyages, that the traveller should take a sufficient quantity
with him. Pure spirits of wine is best. Methylated spirits may be
recommended on account of their cheapness; however, specimens do not
keep equally well in this fluid, and very valuable objects, or such as
are destined for minute anatomical examination, should always be kept
in pure spirits of wine. If the collector has exhausted his supply of
spirits he may use arrack, cognac, or rum, provided that the fluids
contain a sufficient quantity of alcohol. Generally speaking, spirits
which, without being previously heated, can be ignited by a match or
taper, may be used for the purposes of conservation. The best method
to test the strength of the spirits is the use of a hydrometer. It
is immersed in the fluid to be measured, and the deeper it sinks the
stronger is the spirit. On its scale the number 0 signifies what is
called proof spirit, the lowest degree of strength which can be used
for the conservation of fish for any length of time. Spirits, in which
specimens are packed permanently, should be from 40 to 60 above proof.
If the hydrometers are made of glass they are easily broken, and
therefore the traveller had better provide himself with three or four
of them, their cost being very trifling. Further, the collector will
find a small distilling apparatus very useful. By its means he is able
not only to distil weak and deteriorated spirits or any other fluid
containing alcohol, but also, in case of necessity, to prepare a small
quantity of drinkable spirits.
Of collecting vessels we mention first those which the collector
requires for daily use. Most convenient are four-sided boxes made of
zinc, 18 in. high, 12 in. broad, and 5 in. wide. They have a round
opening at the top of 4 in. diameter, which can be closed by a strong
cover of zinc of 5 in. diameter, the cover being screwed into a raised
rim round the opening. In order to render the cover air-tight, an
indiarubber ring is fixed below its margin. Each of these zinc boxes
fits into a wooden case, the lid of which is provided with hinges and
fastenings, and which on each side has a handle of leather or rope, so
that the box can be easily shifted from one place to another. These
boxes are in fact made from the pattern of the ammunition cases used
in the British army, and extremely convenient, because a pair can be
easily carried strapped over the shoulders of a man or across the
back of a mule. The collector requires at least two, still better
four or six, of these boxes. All those specimens which are received
during the day are deposited in them, in order to allow them to be
thoroughly penetrated by the spirit, which must be renewed from time
to time. They remain there for some time under the supervision of the
collector, and are left in these boxes until they are hardened and
fit for final packing. Of course, other more simple vessels can be
used and substituted for the collecting boxes. For instance, common
earthenware vessels, closed by a cork or an indiarubber covering,
provided they have a wide mouth at the top, which can be closed so
that the spirit does not evaporate, and which permits of the specimens
being inspected at any moment without trouble. Vessels in which the
objects are permanently packed for the home journey are zinc boxes of
various sizes, closely fitting into wooden cases. Too large a size
should be avoided, because the objects themselves may suffer from the
superimposed weight, and the risk of injury to the case increases with
its size. It should hold no more than 18 cubic feet at most, and what,
in accordance with the size of the specimens, has to be added in length
should be deducted in depth or breadth. The most convenient cases,
but not sufficient for all specimens, are boxes 2 feet in length, 1½
foot broad, and 1 foot deep. The traveller may provide himself with
such cases ready made, packing in them other articles which he wants
during his journey; or he may find it more convenient to take with him
only the zinc plates cut to the several sizes, and join them into boxes
when they are actually required. The requisite wooden cases can be
procured without much difficulty almost everywhere. No collector should
be without the apparatus and materials for soldering, and he should be
well acquainted with their use. Also a pair of scissors to cut the zinc
plates are useful.
Wooden casks are not suitable for the packing of specimens preserved
in spirits, at least not in tropical climates. They should be used in
cases of necessity only, or for packing of the largest examples, or for
objects preserved in salt or brine.
Very small and delicate specimens should never be packed together with
larger ones, but separately, in small bottles.
_Mode of preserving._--All fishes, with the exception of very
large ones (broad kinds exceeding 3–4 feet in length; eel-like kinds
more than 6 feet long), should be preserved in spirits. A deep cut
should be made in the abdomen between the pectoral fins, another in
front of the vent, and one or two more, according to the length of
the fish, along the middle line of the abdomen. These cuts are made
partly to remove the fluid and easily decomposing contents of the
intestinal tract, partly to allow the spirit quickly to penetrate into
the interior. In large fleshy fishes several deep incisions should
be made with the scalpel into the thickest parts of the dorsal and
caudal muscles, to give ready entrance to the spirits. The specimens
are then placed in one of the provisional boxes, in order to extract,
by means of the spirit, the water of which fishes contain a large
quantity. After a few days (in hot climates after 24 or 48 hours) the
specimens are transferred into a second box with stronger spirits, and
left therein for several days. A similar third and, in hot climates
sometimes a fourth, transfer is necessary. This depends entirely on
the condition of the specimens. If, after ten or fourteen days of
such treatment the specimens are firm and in good condition, they may
be left in the spirits last used until they are finally packed. But
if they should be soft, very flexible, and discharge a discoloured
bloody mucus, they must be put back in spirits at least 20° over proof.
Specimens showing distinct signs of decomposition should be thrown
away, as they imperil all other specimens in the same vessel. Neither
should any specimen in which decomposition has commenced when found, be
received for the collecting boxes, unless it be of a very rare species,
when the attempt may be made to preserve it separately in the strongest
spirits available. The fresher the specimens to be preserved are, the
better is the chance of keeping them in a perfect condition. Specimens
which have lost their scales, or are otherwise much injured, should not
be kept. Herring-like fishes, and others with deciduous scales, are
better wrapped in thin paper or linen before being placed in spirits.
The spirits used during this all-important process of preservation
loses, of course, gradually in strength. As long as it keeps 10° under
proof it may still be used for the first stage of preservation, but
weaker spirits should be re-distilled; or, if the collector cannot do
this, it should be at least filtered through powdered charcoal before
it is mixed with stronger spirits. Many collectors are satisfied with
removing the thick sediment collected at the bottom of the vessel,
and use their spirits over and over again without removing from it by
filtration the decomposing matter with which it has been impregnated,
and which entirely neutralises the preserving property of the spirits.
The result is generally the loss of the collection on its journey
home. The collector can easily detect the vitiated character of his
spirits by its bad smell. He must frequently examine his specimens; and
attention to the rules given, with a little practice and perseverance,
after the possible failure of the first trial, will soon insure to
him the safety of his collected treasures. The trouble of collecting
specimens in spirits is infinitely less than that of preserving skins
or dry specimens of any kind.
When a sufficient number of well-preserved examples have been brought
together, they should be sent home by the earliest opportunity. Each
specimen should be wrapped separately in a piece of linen, or at least
soft paper; the specimens are then packed as close as herrings in the
zinc case, so that no free space is left either at the top or on the
sides. When the case is full, the lid is soldered on, with a round
hole about half an inch in diameter near one of the corners. This hole
is left in order to pour the spirit through it into the case. Care is
taken to drive out the air which may remain between the specimens,
and to surround them completely with spirits, until the case is quite
full. Finally, the hole is closed by a small square lid of tin being
soldered over it. In order to see whether the case keeps in the spirit
perfectly, it is turned upside down and left over night. When all is
found to be securely fastened, the zinc case is placed into the wooden
box and ready for transport.
Now and then it happens in tropical climates that collectors are unable
to keep fishes from decomposition even in the strongest spirits without
being able to detect the cause. In such cases a remedy will be found in
mixing a small quantity of arsenic or sublimate with the spirits; but
the collector ought to inform his correspondent, or the recipient of
the collection, of this admixture having been made.
In former times fishes of every kind, even those of small size, were
preserved dry as flat skins or stuffed. Specimens thus prepared admit
of a very superficial examination only, and therefore this method of
conservation has been abandoned in all larger museums, and should be
employed exceptionally only, for instance on long voyages overland,
during which, owing to the difficulty of transport, neither spirits
nor vessels can be carried. To make up as much as possible for the
imperfection of such specimens, the collector ought to sketch the
fish before it is skinned, and to colour the sketch if the species
is ornamented with colours likely to disappear in the dry example.
Collectors who have the requisite time and skill, ought to accompany
their collections with drawings coloured from the living fishes; but
at the same time it must be remembered that, valuable as such drawings
are if accompanied by the originals from which they were made, they can
never replace the latter, and possess a subordinate scientific value
only.
Very large fishes can be preserved as skins only; and collectors are
strongly recommended to prepare in this manner the largest examples
obtainable, although it will entail some trouble and expense. So
very few large examples are exhibited in museums, the majority of the
species being known from the young stage only, that the collector will
find himself amply recompensed by attending to these desiderata.
Scaly fishes are skinned thus: with a strong pair of scissors an
incision is made along the median line of the abdomen from the foremost
part of the throat, passing on one side of the base of the ventral
and anal fins, to the root of the caudal fin, the cut being continued
upwards to the back of the tail close to the base of the caudal. The
skin of one side of the fish is then severed with the scalpel from the
underlying muscles to the median line of the back; the bones which
support the dorsal and caudal are cut through, so that these fins
remain attached to the skin. The removal of the skin of the opposite
side is easy. More difficult is the preparation of the head and
scapulary region; the two halves of the scapular arch which have been
severed from each other by the first incision are pressed towards the
right and left, and the spine is severed behind the head, so that now
only the head and shoulder bones remain attached to the skin. These
parts have to be cleaned from the inside, all soft parts, the branchial
and hyoid apparatus, and all smaller bones, being cut away with the
scissors or scraped off with the scalpel. In many fishes, which
are provided with a characteristic dental apparatus in the pharynx
(Labroids, Cyprinoids), the pharyngeal bones ought to be preserved,
and tied with a thread to the specimen. The skin being now prepared so
far, its entire inner surface as well as the inner side of the head are
rubbed with arsenical soap; cotton-wool, or some other soft material is
inserted into any cavities or hollows, and finally a thin layer of the
same material is placed between the two flaps of the skin. The specimen
is then dried under a slight weight to keep it from shrinking.
The scales of some fishes, as for instance of many kinds of herrings,
are so delicate and deciduous that the mere handling causes them to rub
off easily. Such fishes may be covered with thin paper (tissue-paper
is the best), which is allowed to dry on them before skinning. There
is no need for removing the paper before the specimen has reached its
destination.
Scaleless Fishes, as Siluroids and Sturgeons, are skinned in the same
manner, but the skin can be rolled up over the head; such skins can
also be preserved in spirits, in which case the traveller may save to
himself the trouble of cleaning the head.
Some Sharks are known to attain to a length of 30 feet, and some Rays
to a width of 20 feet. The preservation of such gigantic specimens is
much to be recommended, and although the difficulties of preserving
fishes increase with their size, the operation is facilitated, because
the skins of all Sharks and Rays can easily be preserved in salt and
strong brine. Sharks are skinned much in the same way as ordinary
fishes. In Rays an incision is made not only from the snout to the end
of the fleshy part of the tail, but also a second across the widest
part of the body. When the skin is removed from the fish, it is placed
into a cask with strong brine mixed with alum, the head occupying the
upper part of the cask; this is necessary, because this part is most
likely to show signs of decomposition, and therefore most requires
supervision. When the preserving fluid has become decidedly weaker from
the extracted blood and water, it is thrown away and replaced by fresh
brine. After a week’s or fortnight’s soaking the skin is taken out of
the cask to allow the fluid to drain off; its inner side is covered
with a thin layer of salt, and after being rolled up (the head being
inside) it is packed in a cask, the bottom of which is covered with
salt; all the interstices and the top are likewise filled with salt.
The cask must be perfectly water-tight.
Of all larger examples of which the skin is prepared, the measurements
should be taken before skinning so as to guide the taxidermist in
stuffing and mounting the specimens.
Skeletons of large osseous fishes are as valuable as their skins. To
preserve them it is only necessary to remove the soft parts of the
abdominal cavity and the larger masses of muscle, the bones being left
in their natural continuity. The remaining flesh is allowed to dry on
the bones, and can be removed by proper maceration at home. The fins
ought to be as carefully attended to as in a skin, and of scaly fishes
so much of the external skin ought to be preserved as is necessary
for the determination of the species, as otherwise it is generally
impossible to determine more than the genus.
A few remarks may be added as regards those Faunæ, which promise most
results to the explorer, with some hints as to desirable information on
the life and economic value of fishes.
It is surprising to find how small the number is of the freshwater
faunæ which may be regarded as well explored; the rivers of Central
Europe, the Lower Nile, the lower and middle course of the Ganges,
and the lower part of the Amazons are almost the only fresh waters
in which collections made without discrimination would not reward
the naturalist. The oceanic areas are much better known; yet almost
everywhere novel forms can be discovered and new observations
made. Most promising and partly quite unknown are the following
districts:--the Arctic Ocean, all coasts south of 38° lat. S., the
Cape of Good Hope, the Persian Gulf, the coasts of Australia (with the
exception of Tasmania, New South Wales, and New Zealand), many of the
little-visited groups of Pacific islands, the coasts of north-eastern
Asia north of 35° lat. N., and the western coasts of North and South
America.
No opportunity should be lost to obtain _pelagic_ forms,
especially the young larva-like stages of development abounding on the
surface of the open ocean. They can be obtained without difficulty by
means of a small narrow meshed net dragged behind the ship. The sac
of the net is about 3 feet deep, and fastened to a strong brass-ring
2 or 2½ feet in diameter. The net is suspended by three lines passing
into the strong main line. It can only be used when the vessel moves
very slowly, its speed not exceeding three knots an hour, or when a
current passes the ship whilst at anchor. To keep the net in a vertical
position the ring can be weighted at one point of its circumference;
and by using heavier weights two or three drag-nets can be used
simultaneously at different depths. This kind of fishing should be
tried at night as well as day, as many fishes come to the surface only
after sunset. The net must not be left long in the water, from 5 to 20
minutes only, as delicate objects would be sure to be destroyed by the
force of the water passing through the meshes.
Objects found floating on the surface, as wood, baskets, seaweed,
etc., deserve the attention of the travellers, as they are generally
surrounded by small fishes or other marine animals.
It is of the greatest importance to note the longitude and latitude at
which the objects were collected in the open ocean.
Fishing in great depths by means of the dredge, can be practised
only from vessels specially fitted out for the purpose; and the
success which attended the “Challenger,” and North American Deep-sea
explorations, has developed Deep-sea fishing into such a speciality
that the requisite information can be gathered better by consulting the
reports of those expeditions than from a general account, such as could
be given in the present work.
Fishes offer an extraordinary variety with regard to their habits,
growth, etc., so that it is impossible to enumerate in detail the
points of interest to which the travellers should pay particular
attention. However, the following hints may be useful.
Above all, detailed accounts are desirable of all fishes forming
important articles of trade, or capable of becoming more generally
useful than they are at present. Therefore, deserving of special
attention are the Sturgeons, Gadoids, Thyrsites and Chilodactylus,
Salmonoids, Clupeoids. Wherever these fishes are found in sufficient
abundance, new sources may be opened to trade.
Exact observations should be made on the fishes the flesh of which is
poisonous either constantly or at certain times and certain localities;
the cause of the poisonous qualities as well as the nature of the
poison should be ascertained. Likewise the poison of fishes provided
with special poison-organs requires to be experimentally examined,
especially with regard to its effects on other fishes and animals
generally.
All observations directed to sex, mode of propagation, and development,
will have special interest: thus those relating to secondary sexual
characters, hermaphroditism, numeric proportion of the sexes, time of
spawning and migration, mode of spawning, construction of nests, care
of progeny, change of form during growth, etc.
If the collector is unable to preserve the largest individuals of a
species that may come under his observation he should note at least
their measurements. There are but few species of fishes of which the
limit of growth is known.
The history of Parasitic Fishes is almost unknown, and any
observations with regard to their relation to their host as well as to
their early life will prove to be valuable; nothing is known of the
propagation of fishes even so common as Echeneis and Fierasfer, much
less of the parasitic Freshwater Siluroids.
The temperature of the blood of the larger freshwater and marine
species should be exactly measured.
Many pelagic and deep-sea fishes are provided with peculiar small
round organs of a mother-of-pearl colour, distributed in series along
the side of the body, especially along the abdomen. Some zoologists
consider these organs as accessory eyes, others (and it appears to
us with better reason) as luminous organs. They deserve an accurate
microscopic examination made on fresh specimens; and their function
should be ascertained from observation of the living fishes, especially
also with regard to the question, whether or not the luminosity (if
such be their function) is subject to the will of the fish.
[Illustration: Fig. 321.--Scopelus boops, a pelagic fish, with
luminous organs.]
INDEX.
Abdominal Cavity, 123
Abdominal fins, 42
Abramis, 602
Abrostomus, 596
Acanthaphritis, 466
Acanthias, 331
Acanthicus, 576
Acanthobrama, 604
Acanthoclinus, 498
Acanthodes, 355
Acanthodini, 355
Acantholabrus, 528
Acanthonus, 547
Acanthophthalmus, 606
Acanthopsis, 606
Acanthopterygiau, 41
Acanthopterygii, 374
Acanthorhodeus, 601
Acanthurus, 438, 439
Acanus, 421
Acara, 536
Acclimatisation, 185
Acentronura, 683
Acerina, 378
Acestra, 579
Achilognathus, 601
Acipenser, 361
Acipenseridæ, 360
Acrochilus, 601
Acrochordonichthys, 567
Acrodus, 330
Acrogaster, 421
Acrognathus, 631
Acrolepis, 370
Acronuridæ, 438
Acronurus, 439
Acropoma, 395
Acyprinoid division, 218
Adipose eyelid, 113
Adipose fin, 42
Aegæonichthys, 476
Aellopos, 325
Aelurichthys, 569
Aesopia, 558
Aëtobatis, 345
African region, 227
Agassiz, 20, 31, 32
Ageniosus, 572
Agnus, 463
Agoniates, 610
Agonostoma, 504
Agonus, 480
Agrammus, 491
Agriopus, 416
Ailia, 566
Aipichthys, 441
Air-bladder, 142
Akysis, 567
Albacore, 458
Albinism, 183
Alborella, 604
Albula, 660
Albulichthys, 596
Alburnus, 603
Alepocephalus, 664
Alestes, 608
Ale-wife, 659
Alisphenoid, 56, 88
Allice Shad, 659
Alopecias, 322
Ambassis, 393
Amblyopsis, 618
Amblyopus, 489
Amblypharyngodon, 598
Amblypterus, 370
Amblyrhynchichthys, 596
Amia, 372
Amioidei, 370
Amiurus, 567
Ammocoetes, 693
Ammodytes, 550
Ammopleurops, 559
Ammotretis, 557
Amphioxus, 696
Amphipnous, 668
Amphiprion, 525
Amphisile, 509
Amphistium, 442
Anabas, 516
Anableps, 617
Anacanthini, 537
Anacanthus, 684
Anacyrtus, 611
Anal fin, 40, 42
Anampses, 529
Anapterus, 582
Anarrhichas, 492
Anastomus, 608
Anchovy, 656
Ancistrodon, 319
Ancylodon, 430
Anema, 463
Anenchelum, 433
Angel-fish, 334
Angler, 470
Anguilla, 671
Angular bone, 54, 91
Anomalops, 449
Anoplogaster, 422
Antarctic ocean, 289
Antennarius, 473
Anthias, 380
Anticitharus, 556
Antigonia, 449
Aphanopus, 434
Aphareus, 390
Aphoristia, 559
Aphredoderus, 396
Aphritis, 466
Aphyocharax, 610
Aphyocypris, 598
Aphyonus, 548
Apionichthys, 559
Apistus, 415
Aploactis, 417
Apocryptes, 487
Apodichthys, 496
Apogon, 394
Apophyses, 51
Appendices pyloricæ, 131
Aprion, 397
Apsilus, 397
Apua, 606
Arapaima, 654
Archæus, 442
Archipterygium, 74
Arctic ocean, 261
Arctic zone, 241
Argentina, 650
Arges, 575
Argyropelecus, 628
Argyriosus, 443
Aristotle, 1
Arius, 569
Arnoglossus, 556
Arrhamphus, 621
Arripis, 393
Artedi, 9
Artedius, 480
Arthropterus, 342
Articulary bone, 54, 90
Articulated rays, 40
Asima, 405
Aspidoparia, 602
Aspidophoroides, 480
Aspidorhynchidæ, 369
Aspius, 603
Aspredo, 580
Aspro, 379
Astracanthus, 314
Astrape, 340
Astrolepis, 354
Astronesthes, 629
Astrophysus, 572
Astroplebus, 575
Astroptychius, 314
Ateleopus, 553
Atherina, 500
Atherinichthys, 501
Atlantic, tropical, 278
Atlantic, northern, 262
Atopochilus, 570
Atopomycterus, 689
Atypichthys, 402
Auchenaspis, 354
Auchenipterus, 572
Auchenoglanis, 569
Aulacocephalus, 383
Aulolepis, 631
Aulichthys, 508
Auliscops, 507, 508
Aulopus, 587
Aulopyge, 596
Aulorhynchus, 508
Aulostoma, 507, 508
Ausonia, 455
Ausonius, 3
Autochthont, 214
Autostylic skull, 71
Auxis, 459
Avola, 604
Badis, 418
Baer, 32
Bagarius, 570
Bagrichthys, 567
Bagroides, 567
Bagropsis, 568
Bagrus, 567
Baird, 29
Bakker, 32
Balfour, 32, 33
Balistes, 684
Ballan Wrasse, 527
Band-fish, 490
Barbel, 594
Barbels, 37
Barbichthys, 596
Barbus, 594
Barilius, 602
Barracuda, 437, 499
Barramunda, 357
Barynotus, 596
Basibranchial, 58
Basihyal, 58
Basioccipital, 56, 87
Basisphenoid, 56, 57, 89
Basking shark, 322
Bass, 376
Bastard Dorey, 388
Bathydraco, 465
Bathygadus, 552
Bathylagus, 650
Bathynectes, 547
Bathyophis, 629
Bathypterois, 583
Bathysaurus, 582
Bathythrissa, 668
Bathytroctes, 664
Batoidei, 335
Batrachocephalus, 570
Batrachus, 467
Bayad, 567
Bdellostoma, 695
Becker, 408
Bellows-fish, 509
Belodontichthys, 566
Belon, 3
Belone, 620
Belonesox, 617
Belonostomus, 369
Bembras, 480
Benedenius, 370
Benthophilus, 489
Berycidæ, 420
Berycopsis, 421
Beryx, 422
Betta, 518
Bib, 541
Bichir, 364
Bitterling, 601
Black Bass, 393
Black-fish, 452, 527
Black Head, 596
Black Horses, 589
Black Sea-bream, 406
Blanchard, 28
Bleak, 604
Bleeker, 30
Bleekeria, 550
Blenniidæ, 492
Blenniops, 496
Blennius, 493
Blennodesmus, 538
Blennophis, 498
Blenny, 492
Blepsias, 480
Blind fish, 618
Bloch, 13
Blood-corpuscles, 150
Blue-fish, 447
Boar-fish, 388, 449
Bocage, 28
Bocourt, 31
Bola, 602
Boleophthalmus, 487
Boleosoma, 379
Bolty, 535
Bombay-duck, 584
Bonaparte, 28
Bonelli, 7
Bonito, 458
Bony Pike, 367
Borer, 694
Botia, 605
Bovichthys, 465
Bow-fin, 372
Box, 406
Brachionichthys, 474
Brachymystax, 646
Brachypleura, 556
Brackish water fishes, 250
Brain, 97
Brama, 454
Branched rays, 40
Branchiæ, 136
Branchial arches, 58
Branchiostegals, 39, 58, 91
Branchiostoma, 696
Bream, 602
Bregmaceros, 545
Brill, 555
British district, 263
Brontes, 575
Brook-trout, 646
Brosmius, 546
Brotula, 546
Brotulophis, 549
Brünnich, 13
Brycon, 610
Bryconæthiops, 610
Bryconops, 610
Bryttus, 396
Buccal cavity, 123
Bulbus aortæ, 152
Bull-head, 476
Bull-trout, 644
Bulti, 535
Buffaloe, 589
Bummaloh, 584
Bungia, 596
Bunocephalichthys, 580
Bunocephalus, 580
Bunocottus, 480
Burbot, 544
Bursa entiana, 128
Burton Skate, 341
Butter-fish, 496, 533
Bynni, 594
Bythites, 549
Cachius, 604
Cænotropus, 607
Cæsio, 390
Calamoichthys, 364
Californian district, 271
Calamostoma, 680
Callanthias, 381
Callichrous, 566
Callichthys, 575
Callionymus, 489
Callipteryx, 462
Callomystax, 573
Callophysus, 569
Callorhynchus, 350
Callyodon, 532
Camper, 16
Campostoma, 596
Cantharina, 405
Cantharus, 405
Cantor, 30
Capelin, 647
Capello, 28
Cape of Good Hope, 283
Capitodus, 405
Capoëta, 593
Capros, 449
Carangidæ, 440
Carangopsis, 442
Caranx, 442
Carapus, 667
Carassius, 591
Carboniferous fishes, 196
Carcharias, 316
Carchariidæ, 316
Carcharodon, 320
Carcharopsis, 319
Cardlike teeth, 126
Caribe, 613
Carmoot, 563
Carp, 589
Carpals, 59
Carpiodes, 589
Cartilage-bones, 87
Castelnau, 31
Cataphracti, 480
Cat-fishes, 568
Catla, 592
Catopra, 418
Catoprion, 613
Catostomus, 589
Caturidæ, 371
Caudal fin, 40
Cebidichthys, 498
Central American district, 279
Centrarchus, 396
Centridermichthys, 477
Centrina, 331
Centriscus, 509
Centrolabrus, 528
Ceutrolepis, 370
Centrolophus, 452
Centromochlus, 572
Centronotus, 496
Centrophorus, 331
Centropogon, 417
Centropomus, 379
Ceutropristis, 380
Centroscyllium, 332
Centrum, 51
Cephalacanthus, 482
Cephalaspis, 353
Cephaloptera, 347
Cephenoplosus, 368
Cepola, 490
Ceratias, 472
Ceratichthys, 596
Ceratobranchial, 58
Ceratodus, 357
Ceratohyal, 58
Ceratoptera, 347
Cerebellum, 97
Cestracion, 330
Cestraciontidæ, 328
Cetengraulis, 656
Cetopsis, 572
Chaca, 564
Chad, 408
Chænichthys, 466
Chætobranchus, 537
Chætodon, 398
Chætopterus, 390
Chætostomus, 576
Chalceus, 610
Chalcinopsis, 610
Chalcinus, 610
Champsodon, 464
Channa, 513
Chanodichthys, 604
Chanos, 662
Characinidæ, 606
Characodon, 615
Charr, 645
Chasmodes, 494
Chatoëssus, 657
Chauliodus, 628
Chaunax, 474
Cheilio, 530
Chela, 604
Chelmo, 399
Chiasmodus, 546
Chilian district, 288
Chilinus, 528
Chilobranchus, 669
Chilodactylus, 411
Chilodipterus, 395
Chilomycterus, 689
Chilorhinus, 674
Chiloscyllium, 326, 327
Chimæra, 349
Chimæridæ, 348
Chimarrhichthys, 466
Chiracanthus, 355
Chirocentrites, 656
Chirocentrodon, 660
Chirocentrus, 663
Chirodon, 609
Chirodus, 370
Chirolepis, 370
Chironemus, 411
Chirus, 491
Chlorophthalmus, 587
Chœrops, 530
Chologaster, 618
Chomatodus, 329
Chondropterygii, 313
Chondrostei, 360
Chondrosteus, 363
Chondrostoma, 600
Chorda dorsalis, 63
Chorinemus, 446
Chorismodactylus, 417
Chorisochismus, 512
Chromatophors, 183
Chromides, 534
Chromis, 535
Chrysichthys, 567
Chrysophrys, 409
Chub, 596, 599, 600
Cichla, 536
Cichlops, 466
Circulation, organs of, 150
Cirrhilabrus, 530
Cirrhina, 596
Cirrhites, 411
Cirrhitidæ, 410
Cirrostomi, 696
Citharichthys, 556
Citharinus, 607
Citharus, 556
Cladacanthus, 314
Cladodus, 328
Clarias, 563
Clarotes, 567
Claspers, 167
Clavicula, 59, 92
Clepticus, 530
Climbing Perch, 516
Clinus, 495
Cloudy Bay cod, 549
Clupea, 658
Clupeichthys, 660
Clupeoides, 660
Cnidoglanis, 564
Coal-fish, 541
Cobitis, 605
Coccia, 628
Coccosteus, 351
Cochlognathus, 596
Cochliodus, 329
Cock-and-hen Paddle, 484
Cod-fishes, 539
Cœcal stomach, 130
Coelacanthidæ, 365
Coelodus, 367
Coelogaster, 656
Coelonotus, 681
Coelorhynchus, 433
Coffer-fish, 686
Coilia, 657
Collichthys, 430
Commerson, 13
Conger, 673
Congrogadina, 550
Congromuræna, 674
Conodon, 386
Conodonts, 193
Conodus, 368
Conorhynchus, 569
Conus arteriosus, 151
Cook, 527
Copidoglanis, 564
Coracoid, 59, 92
Coral-fishes, 397, 525
Corax, 317
Coregonus, 647
Coridodax, 533
Coris, 530
Cork-wing, 527
Cornide, 13
Corpora quadrigemina, 103
Corpora restiformia, 99
Corpora striata, 100
Corvina, 430
Corvo, 429
Corynopoma, 607
Coryphæna, 452
Coryphænoides, 552
Cosmolepis, 370
Cosmoptychius, 370
Cossyphus, 528
Costa, 28
Cottoperca, 466
Cottus, 476
Cotylis, 512
Couch, 27
Couchia, 544
Craig-fluke, 557
Creagrutus, 610
Cremnobates, 495
Crenicichla, 537
Crenidens, 406
Crenilabrus, 527
Crenuchus, 612
Crepidogaster, 513
Cretaceous fishes, 199
Cricacanthus, 314
Cristiceps, 495
Crossochilus, 596
Crossognathus, 656
Crossorhinus, 328
Crossostoma, 604
Crucian carp, 591
Crura cerebri, 98
Cryptacanthodes, 496
Cryptopterus, 566
Ctenododipteridæ, 359
Ctenodus, 359
Ctenoid scales, 46
Ctenolabrus, 527
Ctenopharyngodon, 601
Ctenopoma, 516
Ctenoptychius, 329
Cubiceps, 456
Culter, 604
Curimatus, 607
Cut-lips, 596
Cuvier, 17
Cyathaspis, 354
Cybium, 459
Cyclobatis, 340
Cycloid scales, 46
Cyclopoma, 375
Cyclopterus, 484
Cycloptychius, 370
Cyclostomata, 691
Cyclurus, 588
Cyema, 670
Cymolutes, 530
Cynodon, 611
Cynoglossus, 558
Cynolebias, 615
Cyprinidæ, 587
Cyprinion, 598
Cyprinodon, 614
Cyprinoid division, 217
Cyprinus, 589
Cyttidæ, 450
Cyttus, 451
Dab, 557
Dace, 599, 600
Dactylopterus, 481
Dactyloscopus, 498
Dangila, 596
Danio, 602
Dascyllus, 525
Datnioides, 397
Daurade, 409
Day, 30
Deal-fish, 522
Decodon, 530
Deep-sea fishes, 296
Dekay, 29
Dendrodus, 365
Dentary, 54, 91
Dentex, 389
Dercetis, 666
Dermal spines, 53
Dermoskeleton, 85
Devil-fishes, 344
Devonian fishes, 193, 194
Diagramma, 386
Diana, 455
Dibranchus, 475
Dicerobatis, 347
Dicotylichthys, 689
Dicrotus, 437
Dictyosoma, 498
Didymaspis, 354
Digestion, organs of, 121
Dimeracanthus, 314
Dinematichthys, 549
Dinichthys, 352
Diodon, 689
Dioecious, 157
Diplocrepis, 513
Diplomystax, 569
Diplophos, 629
Diploprion, 383
Diplopterus, 365
Dipnoi, 355
Dipterodon, 406
Dipterus, 359
Diptychus, 595
Diretmus, 449
Discoboli, 483
Discognathus, 593
Discopyge, 340
Distichodus, 612
Ditrema, 534
Dog-fishes, 325, 619
Doliichthys, 487
Dolphins, 453
Domesticated fishes, 185
Domine, 436
Donovan, 17
Doras, 572
Doratonotus, 530
Dorsal fin, 40
Dorsch, 540
Dory, 450
Doryichthys, 681
Doydixodon, 406
Dragonet, 489
Drepane, 402
Drepanephorus, 331
Drum, 427
Ductor, 442
Ductus choledochus, 133
Ductus cysticus, 133
Duhamel, 13
Dules, 384
Duméril, 33
Dussumieria, 662
Duverney, 7
Duymæria, 530
Eagle-Rays, 344
Ear, 116
Echeneis, 460
Echinorhinus, 333
Echiostoma, 629
Ectopterygoid, 90
Edaphodon, 349
Eel, 671
Eel-pout, 544
Egertonia, 526
Elacate, 460
Elasmodus, 349
Elasmognathus, 349
Electric Eel, 667
Electric organs, 94
Electric Rays, 339
Electric Sheath-fish, 574
Eleotris, 488
Elonichthys, 370
Elopichthys, 604
Elops, 661
Embiotocidæ, 533
Encheliophis, 549
Enchelycore, 677
Enchodus, 433
Endoskeleton, 85
Engraulis, 656
Enneodon, 687
Enoplosus, 380
Entopterygoid, 55, 90
Epalzeorhynchus, 596
Ephippus, 402
Epibranchial, 59
Epibulus, 528
Epicoracoid, 59
Epididymis, 167
Epigionichthys, 696
Epihyal, 58
Epinnula, 436
Epioticum, 88
Epiphysis, 98
Epitympanic, 55
Equatorial zone, 218, 272
Eques, 431
Equula, 449
Eremophilus, 581
Erethistes, 580
Ericymba, 596
Erythrichthys, 391
Erythrinus, 607
Escholar, 437
Esox, 624
Etelis, 397
Etheostomatidæ, 379
Ethmoid, 57, 89
Etroplus, 534
Etrumeus, 662
Euanemus, 572
Euctenogobius, 487
Euglyptosternum, 571
Eugnathus, 368
Eulachon, 647
Eulepidotus, 368
Euoxymetopon, 434
Euprotomicrus, 334
Europo-Asiatic region, 243
Eurynotus, 370
Eurypholis, 666
Eurysomus, 370
Eustira, 604
Eutropiichthys, 566
Eutropius, 566
Evorthodus, 487
Exoccipital, 56, 87
Exocoetus, 621
Exoglossum, 596
Exostoma, 580
Eye, 36, 111
Fabricius, 13
Fall-fish, 600
Fierasfer, 549
Fighting-fish, 519
File-fishes, 684
Fins, 40
Fishing-Frog, 470
Fistularia, 507, 508
Fitzroyia, 615
Flat-fishes, 553
Flounder, 557
Flute-mouth, 507
Flying-fish, 621
Flying Gurnard, 482
Forskal, 13
Forster, 13
Freshwater-fishes, 208
Freshwater-Herring, 645
Fries and Ekström, 27
Frog-fish, 470
Frontal bone, 57, 89
Frost-fish, 436
Fuegian sub-region, 248
Fundulus, 615
Gadiculus, 541
Gadidæ, 539
Gadopsis, 537
Gadus, 539
Galapagoes district, 280
Galaxias, 624
Galeichthys, 569
Galeocerdo, 317
Galeoides, 425
Galeus, 318
Gallo, 451
Gambusia, 616
Ganodus, 349
Ganoidei, 350
Ganoid scales, 47
Gar-pike, 367, 620
Gaspereau, 659
Gastrochisma, 455
Gastrocnemus, 452
Gastromyzon, 604
Gastropelecus, 610
Gastrosteus, 505
Gastrotokeus, 682
Gazza, 450
Gegenbaur, 32
Gempylus, 437
Genidens, 569
Genyoroge, 384
Genypterus, 549
Geoffroy, 33
Geophagus, 537
Geotria, 693
Gerres, 388
Gillaroo, 645
Gill-cover, 38
Gill-opening, 38
Gill-rakers, 59, 139
Gills, 136
Gilthead, 409
Ginglymostoma, 326
Girardinus, 618
Girella, 406
Glanidium, 572
Glanis, 566
Glaucosoma, 384
Globe-fish, 687
Glossohyal, 58
Glottis, 149
Glut, 673
Glutinous hag, 694
Glyphidodon, 525
Glyptauchen, 415
Glyptolæmus, 365
Glyptolepis, 365
Glyptopomus, 365
Glyptosternum, 572
Gmelin, 13
Gobiesocidæ, 510
Gobiesox, 513
Gobio, 595
Gobiodon, 487
Gobiosoma, 487
Gobius, 486
Goby, 486
Gold-fish, 591
Gold-Sinny, 527
Gomphodus, 319
Gomphosus, 530
Gonatodus, 370
Goniognathus, 452
Gonorhynchus, 652
Gonostoma, 629
Gourami, 517
Grammistes, 382
Granular teeth, 126
Graphiurus, 365
Grayling, 649
Greenland Shark, 333
Grey Mullet, 501
Grig, 673
Gronow, 12
Growler, 393
Growth of Fishes, 170
Grystes, 392
Gudgeon, 596
Gular plates, 80
Güldenstedt, 13
Gunellichthys, 498
Gunnel-fish, 496
Günther, 27, 30
Gurnard, 479
Gwyniad, 649
Gymnachirus, 558
Gymnarchus, 626
Gymnelis, 538
Gymnocrotaphus, 406
Gymnocypris, 595
Gymnomuræna, 677
Gynmoscopelus, 585
Gymnotus, 667
Gyracanthus, 314
Gyrodus, 367