THE HIPPOPOTAMID^. 375 



The stomacli is divided into three or four compartments, 

 and there is no ccBcum. The liver has a gall-bladder, and 

 the kidneys are lobulated. 



The skeleton is very pig-like, biit in some respects ap- 

 proaches the Ruminants. The centra are slightly convex 

 in front, and concave behind, in the cervical region, but not 

 elsewhere. The prezygapophyses overlap the postzygapo- 

 physes in the posterior dorsolumbar vetebrae. On the other 

 hand, the transvm-se processes of the last lumbar vertebi-as 

 articulate with those of the preceding and succeeding ver- 

 tebrte, as in the Horse and other Perissodactyles. 



In the skull the orbits are nearly complete posteriorly, 

 and they become almost tiibular by the outward production 

 of the frontal and lachrymal bones. 



The nasals and premaxillse imite for a great extent. The 

 osseous palate is long ; the large tympanic bone is 

 ankylosed with the approximated post-glenoidal and post- 

 tympanic processes. 



The mandible is extremely massive, and has a backwardly 

 produced angle. 



The scapvila has a short acromion. The radiiis and ulna 

 are complete and ankylosed, and there are eight bones in 

 the carpiis. The fibula is complete, and the tarsus, which 

 has seven bones, much resembles that of the Pig. 



The SippopotamidcB 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 Suidce and Sippopotamidce, it is interesting to 

 remark the tendency to the coalescence of the metacarpals 

 and metatarsals in Dicottjles; the disappearance of the upper 

 incisors by pairs in Dicotyles, Porcus, and Phacochcems ; and 

 the gi'eat complexity of the stomach in Dicotyles and Hippo- 

 potamus ; as they are so many approximations towards the 

 structure of the Ruminant Artiodactyla. And the tran- 



