PROGRESS OF SYSTEMATIC ZOOLOGY. 383 



first place, some are ambidental 5 , (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 6 , as 

 the boar, some have not. Some have serrated 7 teeth, 

 as the lion, the panther, the dog; some have the 

 teeth unvaried 8 , as the hprse and the ox ; for the 

 animals which vary their cutting-teeth have all ser- 

 rated 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, arid those within broad." 



These passages undoubtedly contain most of the 

 differences on which the asserted Aristotelian clas- 

 sification rests ; but the classification is formed by 

 using the characters drawn from the teeth, in order 

 to subdivide those taken from the feet ; whereas in 

 Aristotle these two sets of characters stand side by 

 side, along with dozens of others ; any selection of 

 which, employed according to any arbitrary method 

 of subordination, might with equal justice be called 

 Aristotle's system. 



Why, for instance, in order to form subdivisions 

 of animals, should we not go on with Aristotle's 

 continuation of the second of the above-quoted 

 passages, instead of capriciously leaping to the third : 

 " Of these some have horns, some have none . . . 

 Some have a fetlock-joint ;) , some have none ... Of 



e XaiAo'Soi/Ta. 



