242 THE ETHIOPIAN REGION. [CHAP. 



appears to be more nearly allied to a small species from the 

 Sicilian and Maltese Pliocene. As already mentioned, with the 

 exception of a single species (Sus sennaariensis], true pigs are 

 unknown in Ethiopia, their place being taken by the two species 

 of bush-pigs, forming the potamochoerine group of the same genus, 

 and distinguished by the simpler structure of the molar teeth, as 

 well as by the tendency of the front premolars to fall out in the 

 adult. The reason for the occurrence of a third species of the 

 group in Madagascar has been already sufficiently discussed 1 . 

 Still more distinctive of the region are the hideous wart-hogs 

 (Phacocharus\ specially characterised by the facial warts from 

 which they take their name, the huge tusks, and the great com- 

 plexity of the last molar tooth in each jaw ; the tusks and these 

 molars being frequently the only teeth remaining in aged animals. 

 It is, however, very noteworthy that certain extinct species of Sus 

 from the Pliocene of India and Algeria have their last molars of a 

 type which could easily be developed into those of the wart-hogs ; 

 and it would accordingly seem that the latter are comparatively 

 recent descendants of ordinary pigs. Although wild camels are 

 unknown in the region, the Tragulida are represented in West 

 Africa by the water-chevrotain, which is now the only existing 

 species of the genus Dorcatherium, although fossil forms occur in 

 the Pliocene of India and the European Miocene ; the ancestral 

 forms having probably entered the region from India. The second 

 ungulate family now confined to Ethiopia is the Giraffidce, of 

 which there appears to be only a single living species, although the 

 North African form shows a decided difference in coloration from 

 its southern brother. The occurrence of species belonging to the 

 existing genus Giraffa in the lower Pliocene of Greece, Persia, 

 India, and China, shows that giraffes came into Africa with the 

 other ruminants ; the African species being very probably the 

 direct descendant of the extinct Indian one. 



Abounding as it does in ungulates in general, Ethiopian Africa 

 is the especial home of the antelope group, which here takes 

 the place of the sheep and goats so characteristic of the elevated 

 districts of the eastern half of the Holarctic region. Regarding 



1 Supra, p. 223. 



