22 ANNALS NEW YORK ACADEMY OF SCIENCES 



the hippopotamus; and some have undivided feet, as the solid-hoofed animals, the 

 horae and ass. The swine kind share both characters [an allusion to the 'mule 

 footed' swine, monstrosities in which the median digits are fused, and terminate in a 

 soUd composite hoof]" (Book II, Chap. V). 



Ray and later writers probably had this passage in mind when they 

 used the descriptive terms "multifido," "bifido," "solidungula," "ungulata," 

 "unguiculata," fissipedes." Here, also, attention is directed to the feet as 

 exhibiting characteristic differences. In another passage Aristotle says, — 



" Animals have also great differences in the teeth both when compared with each 

 other and with man. For all quadrupeds which have blood and are \i\iparous have 

 teeth. And in the first place some are ambidentaP (having teeth in both jaws); 

 and some are not so, wanting the front teeth in the upper jaw. Some have neither 

 front teeth nor horns, as the camel; some have tusks,^ as the boar; some have not. 

 Some have serrated teeth,^ as the lion, the panther, the dog; some have the teeth 

 unvaried,^ as the horse and the ox; for the animals which vary their cutting teeth 

 have all serrated teeth. No animal has both tusks and horns; nor has any animal 

 with serrated teeth either of those weapons. The greater part have the front teeth 

 cutting, and those within broad " (Book I, Chap. II). 



This passage evidently directed the attention of later writers to the 

 importance of the teeth as a means of distinguishing and hence of classi- 

 fying mammals, and we shall see that Ray and, later, Linnaeus were quick 

 to avail themselves of the suggestion. 



Aristotle was quite unconscious of the classification that has been ascribed 

 to him, as Whewell ^ shows; but "Aristotle does show, as far as could be 

 done at bis time, a perception of the need of groups and of names of groups 

 in the study of the animal kingdom, and thus may justly be held up as the 

 great figure in the prelude to the formation of systems which took place in 

 more advanced scientific times." Wbewell also quotes passages that show 

 Aristotle's recognition of the lack »f generic names to denominate natural 

 groups. Aristotle says that "of the class of viviparous quadrupeds there 

 are many genera,^ but these again are without names, except specific names, 

 such as man, lion, stag, horse, dog and the like. Yet there is a genus of 

 animals that have manes, as the horse, the ass, the oreus, the ginnus, the 

 innits and the animal which in S}Tia is called keminus (mule) . . . Where- 

 fore," he adds (that is, because we do not possess genera and generic names 

 of this kind), "we must take the species separately and study the nature of 

 each." "These fassacjes" Whewell continues, "afford us sufficient ground 



' A|X({>o8ovTa. - XavXto'Sovra. ' Kapxopo'SovTa. 



* AvtTroXXaKTa. « Op. cU.. III., p. 350. * EiST]. 



