THE TEETH OF ARTIODACTYLE UNGULATA. 325 



THE TEETH OF ARTIODACTYLE UNGULATA. 



Artiodactyle, or even-toed Ungulata, comprise pigs, hippo- 

 potami, camels, sheep, oxen, &c., amongst living animals. 



They are divided into Ruminant and Non-ruminating animals : 

 the latter group, equivalent to the "Suina" of the table on 

 page 265, includes the Pigs (Shtidai), Hippopotanndce , and Ano- 

 plotheridfs. 



The Ruminants are divided into three groups : (i.) The Tragu- 

 I'ldce (small deer of Southern Asia), which form a connecting link 

 between the Anoplotherium (itself a link between the Pigs and the 

 true Ruminants) and the Pecora ; (ii.) Pecora (sheep, oxen, &c.) ; 

 (iii.) Camelidce. 



In Artiodactyle Ungulata the premolars differ markedly 

 both in size and pattern from the true molars. 



Of those Artiodactyle Ungulates which are not ruminants 

 the common pig may be taken as an example. 



3133 

 The dental formula is i c p m . 



The position of the upper incisors is peculiar, the two 

 central upper incisors, separated at their bases, being inclined 

 towards one another so that their apices are in contact ; the 

 third pair are widely separated from the inner two pairs of 

 incisors. The lower incisors are straight, and are implanted 

 in an almost horizontal position : in both upper and lower 

 jaws the third or outermost incisors are much smaller than 

 the others. 



The lower incisors are peculiar in having upon their upper 

 surfaces a strongly pronounced sharp longitudinal ridge of 

 enamel, which gets obliterated by wear. 



An interval separates the incisors from the canines, which 

 latter are very much larger in the male than in the female, 

 and in the wild boar than in the domesticated animal. 

 Castration arrests the further development of the tusks ; the 

 peculiarities as to size and direction which characterise the 



