76 EXAMINATION OF 



and they are called males *. Our obfervations 

 on this fubjed are extremely limited. 



But to proceed. The male, according to A- 

 riftotle, contains the principle of motion, and 

 the female the material part of generation. The 

 organs deflined for this purpofe are different in 

 different animals. Of thefe the tefticles are the 

 chief in males, and the uterus in females. Qua- 

 drupeds, birds, and cetaceous animals, have tef- 

 ticles ; fifhes and ferpents are deprived of them ; 

 but they have two canals for the reception and 

 maturation of the femen : Thefe parts, fo effential 

 to generation, are always double both in males 

 and females ; and, in the male, they retard the 

 motion of that part of the blood which goes to 

 the formation of femen. This he proves from 

 the example of birds whofe tefticles fwell confi- 

 derably during the feafon of their amours, but 

 afterwards diminifh fo much, that they can 

 hardly be difcovered. 



All quadrupeds covered with hair, and the ce- 

 taceous fifhes, as whales and dolphins, are vivi- 

 parous : But vipers and cartilaginous animals are 

 not properly viviparous ; becaufe they produce 

 an egg within their own bodies, previous to the 

 exclufion of the live animal. Oviparous ani- 

 mals are of two kinds ; thofe which produce 

 peifedt eggs, as birds, lizards, turtles, &c. 

 and thofe which produce imperfect eggs, as 

 llfhes, whofe eggs augment and come to perfec- 

 tion 

 * See Defiandes dans fon tralte de la marine. Paris 1747. 



