THE PLIOCENE PERIOD. 329 
rence of Swine (Swzda), of forms allied to the Camels (Camed/- 
ide), and of various kinds of Deer (Cervide) ; 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 living Hippopotamus 
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 A/ppopotamus 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 Phocene 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 Aastodon Arvernensis (fig. 250), which ranged widely 
Fig. 250.—Third milk-molar of the left side of the upper jaw of AZastodox 
Arvernensis, showing the grinding surface. Pliocene. 
over Southern Europe and England, being generally associated 
with remains of the Hlephas 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 
