44 
OF FISHES IN GENERAL. 
to the three different modes of their generation. Among 
thofe of the firft order, fecundation is accompli died with- 
in the body of the female, by means of a penis intrans , 
as in terreftrial animals. They are all viviparous j that 
is, the female, after having been fecundified by the male, 
and after a certain period of geftation, produces a living 
and perfect animal. 
The cartilaginous are alfo all, except fome fpecies of 
the flurgeon, viviparous ; and among this order too, fe- 
cundation feems to be performed within the body of the 
female, who conceives two or more large eggs, diftin&ly 
containing red find white, like thofe of birds. In thefe 
eggs the fetus is formed ; and, by the white of them, 
it is fed, while it is hatched within the body of the 
mother, without being excluded in the egg ftate, as 
is the cafe in birds. In this ftate, the eggs have 
been found in the belly of a dogfilh, with the young 
completely formed, and of a very confiderable fize *. 
The number of thefe eggs lodged at one time in the 
uterus, is various, according to the fpecies to which 
the animal belongs. One naturalift + obferved in the 
belly of t a dogfilh, fix that w'ere arrived at their full 
fize, befides many others, in which the fetus was fcarce- 
ly formed ; another faw, in the cornua uteri of a tor- 
pedo, fix eggs on one fide, and eight upon the other. 
The mode of generation that obtains among the vivi- 
parous or fpinous fillies, is, from their fituation and man- 
ner of life, involved in great obfeurity. It is generally 
fuppofed, that their eggs are not fecundified, till after 
their exclufion from the matrix of the female. They 
feem, indeed, amidft their evolutions in the deep, to co- 
4 pulate i 
* Rams apud Willough. Lib. I. cap. ix. 
I Francifc. Rcdi. Galei Spinach. 
f Rondeletius, 
