?4i 
ICHTHYOLOGY. 
J.oricarla. - - Body mailed'with a bony coat. 
Salmo. - Hindmoft dorfal fin flelby. 
Notacanthus. - Spines in place of the dorfal fin. 
Fiftularia. - - Snout cylindrical with a cover at the end. 
Efox. - - - Upper jaw much Ihorter than.the lower, 
Elops. - - Branchioftegous membrane double, the 
outer Id's." 
Argentina. - Veac near the tail. 
Atherina.- - Body with a lateral liivery ftripe, 
Mugil. - - Lower jaw carinate inwards. 
Exoccetus. - - Peftoral fins as long as the "body. 
•Polynemus. - Diilinct appendages near the pectoral 
fins. 
•Clupea. - - - Belly carinate, ferrate.' 
-Cyprinus. - - Gill membrane three-rayed. 
V. Branchiostegi. Tl'.is is the firft divifion of car¬ 
tilaginous fifties; having gills deftitute of bony rays. No 
•regard is paid to the fituation of the ventral fins in this 
and the following order. This order contains ten genera: 
fcales imbricate, 
body covered with a 
Mormyrus. , - Teethed notched 
Ollracion. - - Ventral fins none 
bony coat. 
Ventral fins none ; belly prickly. 
Body covered with (pines. 
Ventral fins none ; body covered with 
a Itrong cruft. 
Ventral fins folitary, placed like a keel. 
Ventral fins united; head ending in a 
-narrow fnout. 
Ventral fins two ; fnout ciliate-toothed. 
Ventral fins two, united into an oval 
concavity. 
Ventral fins two, more or lefs refem- 
bling feet. 
VI. Chondropterygii. This order is no otherwife 
diftinguilhed than by having cartilaginous gills. It con¬ 
tains fix genera : 
Ventral fins two ; mouth beneath with¬ 
out teeth. 
Spiracle folitary, quadrifid. 
Spiracles two, ventral. 
Spiracles five, lateral. 
Spiracles five, beneath. 
Spiracles l'even, lateral. 
The Tipper part of the annexed Engraving will exem¬ 
plify the above claftification. 
Fig. i, is an apodal filh, or one having no ventral fins; 
it is the Muraena conger, or conger-eel; and at a is Ihown 
the union of the dorfal, anal, and tail, fins. 
Fig. 2,.isa jugular filh.; having the ventral fins, b, placed 
more forward than the pedorals, a. This is the Gadus 
asglefinus, or haddock ; and may be taken as an example 
to illuftrate the pofition of the fins, See. in general, a is 
a pedoral fin, and b a,ventral fin, as juft obferved; cc, 
anal fins; d, caudal or tail fin ; eee, dorfal or back fins; f, 
bony gill-coverts; g , branchioltegous rays and their mem¬ 
branes ; h, lateral or fide line. 
Fig. 3, is a thoracic filh ; having the ventral fins, a, placed 
diredly under the pedorals, b. It is the Cottus fcorpius, 
or fatheirlalhet;; .having digitated appendages at c. 
Fig. 4, is an abdominal filh ; having the ventral fins, a, 
placed behind or farther back than the pectorals, b. This 
is a lpecies of Cyprinus; having cirrhi, or bearded appen¬ 
dages at c. 
Fig. 5, is a chondropterygious filh, moft of the genera 
of which order breathe through lateral apertures, or fpi- 
racles, as at a. It is the §qualus aeanthias, or picked 
dog-filh. 
GENERATION of FISHES. 
Tetrodon. - 
•Diodpn. - 
"Syngfiathus. 
Baliftes. - 
Centriicus. - - 
Pegafus. 
Cyclopterus. - 
Lophius. - 
Acipenfer. - 
Chi inarm. - 
Gaftrobranchus. 
Squalus. 
-Raia. --- 
Petromyzon. 
and delicate do not perifh in greater numbers, efpeciaTly 
m deep waters,where the ft ream is very rapid, and where 
a valt number of fifties depofit their eggs. The manner 
in which thefe eggs are hatched is not lefs wonderful. 
After the long deep which fifties enjoy during winter,-the 
unit begins to increafe, to fweil, to prefs the inteftines, 
and diftend the extenor parts of the lower belly; this 
•caules a pain, of which the male ftrives to eafe himfelf, 
like the female, by rubbing againft weeds or ftones. As 
the fweil is greater in the females, they are the firft who 
ann at relief by feeking a proper place to depofit their 
eggs. 1 hefe _ eggs, which are covered with a vifcous 
matter, will ftick to plants, ftones, and other hard fub- 
ftances, and are then fecundated by the male in the 
manner which will be prefently deferibed. This gluey 
matter feems to be fecreted for the exprefs purpofe of fa¬ 
cilitating the paftage of the eggs out of the body, as it is 
not to be perceived on thofe which are prematurely forced 
out by p re fling the belly of the female. 
The fpawn or eggs of fillies are very final] in compari- 
fon with thofe of other animals ; thofe of the trout and 
fahnon do liot.exceed the fiz? of a pea; and in a filurus, or 
flieat-fifh, which weighed above a hundred pounds, they 
were found not to be larger than a grain of millet. But 
in quantity the fifties furpafs all other animals ; every 
year they lay a great number: 100,000 have been counted 
in a fiili not.weighing half a pound, and one cod-filh has 
been afceitained to contain 9,000,000. Here we have to 
admire the wife difpenlations of Providence, in adverting 
the manner in which thofe eggs are hatched, and the 
continual dangers to which they are expofed, whether by 
inundations and tempeftsj or by voracious animals who are 
fond of devouring the eggs and young fry. The e^-gs of 
fifties in genera! are not fecundated, like tliofe of other 
animals, in the belly of the mother; when the female lias 
voided them, the male follows in order to ftied upon 
them a feminal liquor which is fecreted in what is called 
the milt : but, as only a fmall part of them receive this li¬ 
quor, the greater part remain barren. Befides, fifties void 
their ova on all kinds of fubftances, which often being 
carried by tempefts or the waves over the banks of the 
water, the fpawti is left on the fhores, and the eggs or 
young are fure to perifti when the waves retire. Sudden 
cold often hinders the female from calling her fpawn, or 
freezes the blood of the young juft hatched. Part of the 
eggs become the prey of the eel, ftickleback, and other 
voracious fifti: water-fowl alfo eat the fame food occa- 
fionally. A want of heat alfo often caufes a part of the 
eggs to remain at the bottom of the water unhatched. In 
general it is found, that among fillies the voracious kinds 
are not only more numerous than among land-animals 
and birds, but that they are alfo more greedy and infati- 
able, not fparing even their own lpecies, which othef’ani- 
raals will not deftroy unlefs driven by the molt preflino- 
hunger. Add to this, the various means which man hat 
contrived to take or deftroy filh ; and it wjli appear, that 
a race expofed to fo many dangers, muft have been exter¬ 
minated long lince, had not Providence endowed the fe¬ 
males with this extraordinary fecundity 
The eggs of filhes are enclofed in a membrane or bag, 
and in moft fpecies in a double one, called ovaries, placed 
before the air-bladder; and near the anus is an aperture 
called the navel, through which they pals. The feminal 
veil'd, or milt, of the male, is always double. If you put 
oil a bit of glafs as much of it as you can take on the 
point of a needle, and then, after diluting it with a drop 
of water, examine it with a microi'cope, you will perceive 
a number of little organil'ed bodies. The l'eminal liquor 
of the female is alfo emitted by the navel. 
As moft filh approach the ftiores and lhallows j-o fpawn. 
The principles of generation in general are covered with that is the time when filhing in general is moft produc 
a dark cloud; but more el'pecially among fillies, where it tive ; for thefe animals are heavy and inactive from the 
is perfeded out of the womb, and in a cold and moilt ele- irritating and voluptuous pain which is caufed by the 
ySient. It is altonilhing that animals fo extremely tender prefl’ure of the fpawn within their bodies, and their anx- 
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