V.] UNGULATES. 185 



Malagasy regions by the potamochcerine group, frequently reckoned 

 as a distinct genus. The Ethiopian region is, however, the sole 

 habitat of the wart-hogs (Phacochoerus}. 



Among extinct artiodactyles we have two well-marked families, 

 distinguished from the foregoing by the crescentic columns of 

 their short-crowned cheek teeth the Anoplotheriidce and Dicho- 

 dontidce likewise confined to Eastern Arctogaea, although their 

 remains have hitherto been obtained only from the eastern section 

 of the Holarctic region. The first of these includes several genera 

 from Oligocene strata, characterised by having three columns on 

 the front half, and two on the hinder half of their upper molars. 

 In the typical Anoplotherium there were forty-four teeth, arranged 



FlG. 44. LAST FIVE RIGHT UPPER CHEEK-TEETH OF AN Anoplotherium. 



in a continuous even series, and the feet were provided with either 

 three or two toes. Dacrytherium differs by the molars being more 

 like those of Ancodus, and also by the deep cavity for the 

 reception of a gland on each side of the face in front of the eye ; 

 while the small and elegantly formed animals described as Xiph- 

 odon have the crowns of the first three premolar teeth elongated 

 and trenchant, the feet being two-toed. In the Dichodontida, of 

 which there are likewise several genera, the cheek-teeth are more 

 completely selenodont, with only four columns on the crowns of 

 the upper molars ; and it is not improbable that in this family we 

 have the ancestral types of both the chevrotains and the deer. 



In the Camelidce, as we have already seen, the typical genus 

 Camelus, which is found living (although not in a wild state) in the 

 Eastern Holarctic, Oriental, and Ethiopian regions, and fossil in 

 the Plistocene of Algeria and the Pliocene of India, is likewise 

 confined to Eastern Arctogsea. And the same is true, both in the 



