ICH 
are elongated, and pointed at their extre- 
mities ; loricated, or mailed, when the body 
is inclosed in a hard, callous, or bony in- 
tegument, or in scales so closely united as 
to seem but one ; fhsciated, or banded, 
when marked witli transverse zones, from 
the back to the belly ; striped, when marked 
with very narrow, scattered, and coloured 
streaks; vittated, when marked with longi- 
tudinal zones along the side, from the head 
to the tail ; reticulated, or chequered, when 
marked with lines forming the appearance 
of net work ; pointed, or dotted, when 
marked with points, either longitudinally 
disposed, or without order ; and variegated, 
when of different colours. 
The head is always placed at the anterior 
part of tire body, and reaches from the ex- 
tremity of the nose to the gills. The head 
contains the mouth, nose, jaws, lips, teeth, 
tongue, palate, nostrils, eyes, branchial 
opercules, the branchiostegous membrane, 
the aperture of the gills, and the nape. The 
branchial opercules are scaly, or bony pro- 
cesses, situated on both sides of the head, 
behind the eyes, closing the aperture of the 
gills, and sustaining the branchial mem- 
brane. The branchial, or branchiostegous 
membrane, is a true fin, formed of cartila- 
ginous crooked bones, joined by a thin 
membrane, lurking under the opercula, to 
which it adheres, and is capable of being 
folded, or expanded, as necessity requires.' 
The trunk is that part of the body which 
extends from the nape and branchial aper- 
ture to the extremity of the tail. It compre- 
hends the gills, throat, thorax, back, sides, 
abdomen, lateral line, anus, tail, and scales. 
The gills, or branchiae, consist, for the most 
part, of four, crooked, parallel, unequal 
bones, furnished on the outer, or convex 
part, with small soft appendages, like the 
beards of a feather, and generally of a red 
colour. 
The fins consist of several rays connected 
by a tender film, or membrane ; and they 
are raised, expanded, or moved, in various 
directions, by means of appropriate mus- 
cles. The rays of the fins are either jointed 
and flexible small bones, whose extremity 
is often divided into two parts, or hard and 
prickly, without division at the extremity. 
In some cases, those on the back of the fish 
are furnished with membranaceous appen- 
dages, simple, or palmated, and adhering to 
the apex, or sides. The fins, according to 
their position, are denominated dorsal, pec- 
toral, ventral, anal, or caudal. 
The skeleton of a fish is the assemblage 
ICH 
of bones which constitutes the frame-work 
of its body. The number of these bones is 
not uniform in each individual, but varies 
according to age and species. They may 
be conveniently divided into those of the 
head, thorax, abdomen, and fins. 
The muscles are an assemblage of small 
bundles of fleshy fibres, partly red, and 
partly whitish, enveloped in a common 
membrane. The first of these is called the 
fleshy portion of the muscle; the second the 
tendon. Each muscle thus composed, is 
susceptible of contraction and dilatation. 
The former is accompanied by a visible 
swelling, hardening, wrinkling, and short- 
ening of the muscle, and the latter by its 
elongation, expansion, and recdvery of its 
former softness and flexibility. Its force, 
in general, depends on the quantity of 
fibrous matter which enters into its compo- 
sition, and its moving power on the length 
and size of the fibres. 
The brain of fishes is a very small organ 
relative to the size of the head. It is di- 
vided into three equal lobes, of which the 
two anterior are contiguous ; the third be- 
ing placed behind, and forming the cerebel- 
lum. These three lobes are surrounded by 
a frothy matter, resembling saliva. In this 
region the optic and olfactory nerves are 
easily discovered. 
The swimming, or air bladder, or sound, 
is an oblong white, membranous bag, some- 
times cylindrical, sometimes elliptical, and 
sometimes divided into two or three lobes, 
of different lengths. It is usually situated 
between the vertebrae and the stomach, and 
included within the peritonaeum. In some 
fishes it communicates with the stomach, 
and in others, with the oesophagus. The 
flat fishes are unprovided with this or- 
gan. 
The intestines, which in man are placed 
transversely, have a longitudinal position in 
fishes, and are all connected with the sub- 
stance of the liver. They are in general 
very short, making only three turns, the 
last of which terminates in a common out- 
let or vent. The appendices, or secondary 
intestines, are very numerous, composing a 
groupeof worm-like processes, all ultimately 
terminating in two large canals, opening 
into the first intestine, into which they dis- 
charge their peculiar fluid. We shall, un- 
der the word Pisces, give an account of 
the several functions peculiar to this class of 
animals. 
ICHTHYOPHTHALMITE, in mine- 
ralogy, a stone found in Sudermania, of a 
