256 THE ETHIOPIAN REGION. [CHAP. 



number were already in existence at the time of the southern 

 migration. Several of these existing genera are met with in the 

 Pikermi deposits of Greece, but more were confined, at this epoch, 

 to the Pliocene of Persia, Samos, and India ; and it may there- 

 fore be assumed that the great migration was by way of Syria or 

 Arabia. Dr Wallace has indeed expressed the opinion that a 

 certain number of types among them the elephants and rhinoce- 

 roses obtained an entrance to the westward of Tunis ; but there 

 are no true elephants in the Pikermi deposits, and apparently 

 none in those of Persia, whereas their remains abound in the 

 Siwalik Hills. As to the rhinoceroses, although the Pikermi 

 species is closely allied to the African Rhinoceros bicornis, the 

 Siwalik R. platyrhinus is equally close to R. simus ; and in the 

 Siwaliks we meet with chimpanzees (Anthropopithecus), baboons 

 (Papio), ratels (Mellivora), hippopotami, water-chevrotains (Dorca- 

 therium\ and several genera of Ethiopian antelopes, all of which 

 are totally unknown in the Pikermi beds. Ostriches, too, are 

 first known in the Siwaliks ; while aard-varks occur in the Persian 

 and Samos beds. All the evidence accordingly points to the 

 great immigration having taken place along the eastern side of the 

 continent ; and the existence of certain species of mammals which 

 are either still common to India and Africa, or which were so 

 during the Plistocene epoch, lends support to this view. Further 

 testimony in this direction is aiforded by the occurrence of closely- 

 allied generic types in the Ethiopian and Oriental regions. 

 Among the lemuroids, for instance, the Oriental lorises (Nycti- 

 cebus and Loris) are replaced in Western Africa by the potto and 

 awantibo (Perodicticus) ; while in the Viverrida the true linsangs 

 (Linsanga) of the eastern half of the Oriental region are repre- 

 sented in Fernando Po by the allied Poiana, and the Oriental 

 palm-civets (Paradoxurus} have very close allies in the two species 

 of the Ethiopian genus Nandinia. A less marked instance is 

 afforded by the occurrence of the water-chevrotain (Dorcatheriuni} 

 in West Africa and of the true chevrotains in southern India and 

 the eastern half of the Oriental region. 



And here it may be remarked that especial stress has been laid 

 upon the much greater resemblance that exists between the fauna 

 of the eastern, or Malayan, division of the Oriental region and 



