THE PLIOCENE PERIOD. 341 



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 in- 

 ferred, with great probability, that the Hippopotamus major was 

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

 its nearly hairless modern fepresentative, 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 

 over Southern Europe and England, being generally associated 

 with remains of the Elephas mcridionalis, E. antiquus, Rhino- 

 ceros megarhinus, and Hippopotamus major. The lower jaw 



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

 Arvernensis, showing the grinding surface. Pliocene. 



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

 incisors are developed into great tusks, which sometimes reach 

 a length of nine feet, and which have the simple curvature of 

 the tusks of the existing Elephants. Amongst the Pliocene 

 Elephants the two most important are the Elcphas mcridionalis 

 and the Elephas antiquus. Of these, the Elcphas mcridionalis 

 (fig. 251) is found abundantly in the Pliocene deposits of 

 Southern Europe and England, and also survived into the 

 earlier portion of the Post-Pliocene period. Its molar teeth 

 are of the type of those of the existing African Elephant, the 

 spaces enclosed by the transverse enamel-plates being more 



