I C H T HI 
From a centre. The fins, however* of fome fifh, are com- 
pofed of rays without a membrane, or of a membrane 
without rays. Thefe rays are bony in fome, cartilaginous 
in others. Of the bony rays there are two kinds : lome 
are folid, long, rather conical, ending in a (harp point, and 
fee'm all of one piece ; thefe are called fimple rays, orJpincs. 
Other bony rays are competed of feveral final! cylindrical 
pieces*placed one over the other; thefe may be called ar¬ 
ticulated rays; but, as the uppernioil of thefe articula¬ 
tions (i.e. thqfe moft diftant from the bafe of the fin) 
generally fpiit into two or more divifions, they are called 
branched’ rays ; or fometimes bifurcated or dichotomous rays. 
Thefe articulations are found in the cartilaginous rays alfo. 
The rays, both fimple and articulated, are in genera! tranf- 
parenf ; but fome of the very ftrong fimple bony rays muft 
be excepted. 
Befides the fins, there are in fome fifhes certain, appen¬ 
dages which, when fituated at, the bread, are called fn- 
gers, or digitated appendages, as in the red gurnet. Others 
have immediately above tlife ventral fins a pointed fub- 
ftance riling from the fkin, which is called the ventral ap¬ 
pendage ; it is cartilaginous, and half covered with feales : 
it is, probable that it fervps in a particular manner to fuf- 
tain the ventral fin. 
Fifties are generally covered on the whole furface with 
a /kin, which is foft and vifeous; however thick it may 
be, it is generally the more flexible and covered with dime 
in proportion as the feales are frnall or fewer in number. 
Several other animals, as ferpents, oviparous quadrupeds, 
and fome of the mammalia clafs, are furnifHed with feales, 
as well as fifhes. Scarcely any fpecies of fifh is really with¬ 
out feales ; there are fome kinds, indeed, upon which the 
niceft eye, even with a microfcope, cannot diftinguifh any 
ltales while the fijh is frefh, and the fkin covered with 
that vifeofity which is more or lefs abundant in all fifh 
but, when the fifh has been fome time dead, and the fkin 
- lias been naturally or artificially dried, there is perhaps no 
fpecies whatever from which a careful operator might not 
detach minute feales, which come away like a fhining 
powder, and form a heap of hard, diaphanous, and bril¬ 
liant, laminae. See the fubjedl refumed farther on, and 
exemplified with figures. 
The form of the feales is various ; fometimes they are 
tapered away into fpines; at others they are thickened 
and railed into tubercles; but moll commonly they are 
fmooth plates, either flat or raifed by a bone. Thefe 
plates, which are-the feales properly fo called, are either 
round, oval, or hexagonal; part of their circumference is 
fometimes minutely-l'errated ; in fome fpecies they are few 
in number, and lie quite apart; in others they join ; in 
others they lie one over the other like tiles upon a houfe. 
They communicate with the body of the fifh by means of 
certain veflels.; but they are alfo attached to the fkin by 
a certain portion, more or iefs, of their circumference. 
It is worthy of remark, that'a vail number of fifh who 
ufually keep in the main ocean, and which are rarely ex- 
pofed to be rubbed againft by approaching the fliores, 
have their feales fallened but by a irnall portion of their 
circumference; but they are more firmly fixed, and co¬ 
vered in part by the epidermis,' in many of thofe which 
frequent the {bores', and which are thence called litorales, 
or fhore-loving; and they are Hill more ftrongly fixed, 
and covered entirely by the epidermis, in moft of thofe 
which live in the mud, and make holes to hide'them- 
lelves in. 
• The ■ teeth are generally flrcng and numerous. They 
are of various fhapes: fome are rather conical or com- 
prefied, lengthened, and fharp-pointed, fometimes ferrated 
on their edges, or preferring many teeth in one, and often 
bent; fome are compreffed, terminating in a broad'cut¬ 
ting edge; others again are almolt hemifpherical, or even 
entirely flatted againft the bafe. They take their, name 
from their fhape and ufe, not from their pofition. The 
grinders are thofe hemifpherical. of much-flattened teeth, 
Vox.. X. No. 709. 
'OLOGY, 737 
which are intended to efufh, brutfe', and" comminute, hard' 
fubflances ; the cutting-teeth are like the front teeth of men. 
and fome quadrupeds, with a broad fliarp edge or blade * 
but the moft numerous are thofe which Cepede calls ’lani- 
ares, or tearing-teeth, which are long, fliarp, often bent or 
hooked in different directions, and ferve to retain, tear* 
and mangle, the prey ; indeed not a ^reat many fifh have 
any but thefe laft. The teeth are covered with an ena¬ 
mel, as in other animals. Some fpecies have the teeth 
fixed in bony or very hard lockets; in others' the roots 
are in membranous capfules only, and the fifh can raife or 
deprefs them, and turn them in different directions at will, 
The conformation of the internal parts of fifhes varies 
in many refpefls from other animals. The tongue is car¬ 
tilaginous: and in many of the voracious fifhes, as the 
trout and the fmelt, it' is even furnifhed with teeth. 
Others, as the carp, have no tongue at all; which makes 
it appear probable, that the tongue in fifhes is rather def- 
tined to retain food than as an organ of tafie. Teeth are 
alfo frequently found on the palate and in the throat. 
To proceed with the examination of the interior parts. 
Next to the throat, which is often very capacious, com¬ 
mences the inteftinal canal, which runs to the anus; but 
it widens in its courfe, and receives the name of fiomach. 
This organ, which lies longitudinally in the body, varifes 
in different fpecies in fhape, fize, thicknefs of its mem¬ 
branes, and the folds or wrinkles formed by thefe mem¬ 
branes. In fome fifh, this canal appears fo plainly di¬ 
vided, that l’uch have been faid to have two flomachs; and. 
its texture in others is truly mufcular, inftead of mem¬ 
branous. Between the two portions of the inteftinal ca¬ 
nal divided by the ftomach, appear certain hollow mem¬ 
branous tubes, opening only towards the inteftines, fome- 
what refembling the axcun*, or blind-gut, in the human 
frame; they are fometimes long, and of lei's diameter thaVi 
the intefline ; fometimes they are thick and very fliorl. 
They are in number from one up to one hundred, accord¬ 
ing to the fpecies. The inteftinal canal is almolt ftraight 
in fome fillies, efpecially in thofe whole bodies are long; 
it returns to the ftomach, and then bends towards the 
anus, in many others; and in fome it makes feveral con¬ 
volutions, and is longer than head, body, and tail, all to¬ 
gether. , 
The poiverof digeftion in fifties is very great; yet this 
does not arife from the aftion of heat, as in men and moll 
animals ; and, on the other hand, the membranes or coats 
of the ftomach are too thin for the purpofes of triturat¬ 
ing or pounding the food to prepare it for decompofition. 
But we find in general that the digeftive juices of fifhes 
are very aSlive and in great quantity. The fpleen is of¬ 
ten triangular, fometimes long, always of a darkjColour; 
the gall-bladder is large; the liver is very large, fometime? 
Angle, fometimes divided into two or three lobes, and 
fometimes as long as the abdomen itfelf. This quantity 
and ftrength of digeftive juices is particularly neceflary to 
thofe fpecies which have fcarcely any finuofity in the in¬ 
teftinal canal, no appendage to the pylorus, no teeth in 
the gullet, and which therefore cannot fo much tear and 
grind their food, nor retain it any conliderable time in 
the inteftines. But this deficiency is fupplied or avoided 
by a peculiar property in fome fpecies : the pike, for ex¬ 
ample, and the reft of the cfox genus, have a faculty which 
has been obferved in rapacious beafts and birds: they 
eafily return by the mouth the fubltances they cannot di- 
geft. 
The urine of fifties is fomewhat of a thicker confiftence 
than iu other animals ; probably becaufe it partakes of 
that oily nature which abounds in all the parts, .of fifties. 
It is flrained through the kidneys, and paffes by the navel. 
The nutritive juices are diflributed by the lymphatics, 
lafteals, and other abforbent veflels., as in other animals; 
and the circulation of the blood is carriect on nearly in 
the fame manner. The heart, which is the principal ill - 
ftrument of circulation, is commonly iijclofed in a verr 
9 B thiift 
