320 THE ANATOMY OF VERTEBRATED ANIMALS. 



osseous palate is long ; the large tympanic bone is anchylosed 

 with the approximated post-gienoidal and post-tympanic pro- 

 cesses. 



The mandible is extremely massive, and has a backwardly 

 produced angle. 



The scapula has a short acromion. The radius and ulna 

 are complete and anchylosed, and there are eight bones in the 

 carpus. The fibula is complete, and the tarsus, which has 

 seven bones, much resembles that of the Pig. 



The Hippopotamidcn are at present confined to Africa; 

 but a species abounded in the rivers of Europe in the later 

 tertiary times. 



Merycopotamus of the miocene Fauna of the Sewalik 

 Hills appears to have been a Hippopotamid, with upper molars 

 having a quadri-crescentic, ruminant-like pattern, and lower 

 molars bi-crescentic and rhinocerotic in character. 



In the SuidoB and Sippopotamidm, it is interesting to 

 remark the tendency to the coalescence of the metacarpals 

 and metatarsals in Dicotyles ; the disappearance of the upper 

 incisors by pairs in Dicotyles, Parens, and Phacochoerus ; and 

 the great complexity of the stomach in Dicotyles and Hippo- 

 potamus ; as they are so many approximations toward the 

 structure of the Ruminant Artiodactyla. And the transition 

 from the non-Ruminant to the Ruminant groups, or rather the 

 common stem of both, is furnished by the Anoplotherida. 



c. The family 'of the Anoplotheridm exclusively contains 

 extinct Marairials belonging to the eocene and miocene epochs. 

 They are most conspicuousl}' distinguished by the circumstance 

 that the teeth, of which there are eleven on each side, above 

 and below, in the adult dentition, are not interrupted by any 

 gap in front of and behind the canine, as they are in the pre- 

 ceding genera, but form an uninterrupted and even series, as 

 in Man. 



The dental formula of the adult Anoplotheriwn is i. y\ 



-J p.m. — in. — , supposing that the first premolar is really 



i-i 



such, and not a persistent milk-molar. 



The upper and lower molars have the general structure of 

 those of the Rhinoceros ; but the lamina? of the upper are Lent 

 more backward into parallelism with the outer wall, and a 

 strong conical pillar is developed on the inner side of the 

 anterior lamina. The skull resembles that of the Ruminant 

 2'ragulidce in structure, but the orbit is incomplete behind 



