THE PLIOCENE PERIOD. 329 



rence of Swine (Suida), of forms allied to the Camels (Camel- 

 ida), and of various kinds of Deer (Cervida); but the most 

 interesting Pliocene Mammal belonging to this section is the 

 great Hippopotamus major of Britain and Europe. This well- 

 known species is very closely allied to the \\vmglfippopotamtis 

 amphibius of Africa, from which it is separated only by its 

 larger dimensions, and by certain points connected with the 

 conformation of the skeleton. It is found very abundantly in 

 the Pliocene deposits of Italy and France, associated with the 

 remains of the Elephant, Mastodon, and Rhinoceros, and it 

 survived into the earlier portion of the Post-Pliocene period. 

 During this last-mentioned period, it extended its range north- 

 wards, and is found associated with the Reindeer, the Bison, 

 and other northern animals. From this fact it has been infer- 

 red, with great probability, that the Hippopotamus major was 

 furnished with a long coat of hair and fur, thus differing from 

 its nearly hairless modern representative, and resembling its 

 associates, the Mammoth and the Woolly Rhinoceros. 



Passing on to the Pliocene Proboscideans, we find that the 

 great Deinotheria of the Miocene have now wholly disappeared, 

 and the sole representatives of the order are Mastodons and 

 Elephants. The most important member of the former group 

 is the Mastodon Arvernensis (fig. 250), which ranged widely 



Fig. 250. Third milk-molar of the left side of the upper jaw of Mastodon 

 Arverttensis, showing the grinding surface. Pliocene. 



over Southern Europe and England, being generally associated 

 with remains of the Elephas meridionalis, . antiquus, Rhino- 

 ceros megarhinus, and Hippopotamus major. The lower jaw 

 seems to have been destitute of incisor teeth ; but the upper 

 incisors are developed into great tusks, which sometimes reach 



