RISE AND PROGRESS OP ZOOLOGY. Jxi 



the teeth, except in the Vespertilio which has 

 this further mark, that there is a membrane at- 

 tached to the feet and sides, enabling it to fly ; 

 in the Hystrix, which is covered with quills, and 

 the whole order of Pecora, the genera of which 

 are further distinguished by the absence, pre- 

 sence, or conformation of horns. 



The specific distinctions in this class are 

 drawn chiefly from the tail of the animal, but 

 in few instances exclusively so, as the feet, ears, 

 breasts, tyc, enter into the description. As in 

 the genera, so in the species of the Pecora, the 

 diversity of the horns seems to constitute vari- 

 ous discriminations. In the Cete the nostrils 

 and jaws are chosen as marks of distinction, 

 these parts in their variations altering very ma- 

 terially the character of the head. The nasal 

 canal or fistula of the cetaceous tribe is differ- 

 ently situated, being not always in the snout 

 or rostrum, but sometimes in the forehead and 

 sometimes in the neck ; and while some species 

 have a simple, others have a double orifice. 

 Colour is but little regarded by Linnaeus, ex- 

 cept in the genus Simia, and in some genera 

 of the Ferse, as Viverra, Mustela, <5fc., in which, 

 being both permanent and striking, he has 

 thought fit to include it in the specific differ- 

 ences 



VOT,. I. Sf 



