130 THE WANDERINGS OF ANIMALS [CH. 



become restricted to the southern countries of the 

 Old World, India and Africa, whence they originally 

 started. 



Swine and Hippopotamus. 



Small swine were plentiful in Upper Eocene 

 Europe, later in North America, where they have 

 left only the Peccaries, which now range from Texas 

 to Argentina. In Eurasia pigs have produced a 

 number of surviving genera. Sus, dating from 

 Upper Miocene, has the widest range, from Ireland 

 (exterminated) and Morocco to' New Guinea and 

 Japan. The Babirusa, with its four up-curled tusks, 

 is peculiar to Celebes. Warthogs and riverhogs are 

 now African, south of the Sahara, with one riverhog 

 also in Madagascar. This is paralleled by the former 

 existence of a small hippopotamus in the same island, 

 allied to the pigmy hippo in Liberia, whilst the hippo, 

 formerly in India and Europe, lives now in Africa, 

 south of the Sahara. 



Camelidae. 



The few surviving members of the Tylopoda, 

 i.e. pad-footed ruminants, tell a remarkable history of 

 dispersal. From the Upper Eocene of North America 

 they can be traced through an unbroken series of 

 still generalised forms into the Pliocene, when they 

 split into early camels, e.g. Procamelus, and early 



