258 THE ETHIOPIAN REGION. [CHAP. 



had taken place from Africa to India, which was not the 

 case. Evidence of such a tract is, I believe, afforded by the 

 occurrence of fossilised tree-stems in many districts which are now 

 desert. And along this tract there can be little doubt that the 

 ancestors of the mammalian types now common to the West 

 African and Malayan sub-regions originally wandered from their 

 common Indian home. Subsequently the whole of the countries 

 lying between eastern Africa and India have become deforested, 

 while in Africa itself the forest-area has shrunk away from the 

 eastern side of the continent. 



This leaves the question of the absence of bears and deer from 

 Africa without any adequate explanation. Bears are, however, in 

 the main, mountain animals, some of which, like the isabelline 

 bear of the Himalaya, inhabit districts where there is but little 

 forest ; and it is noteworthy that, with the exception of the sloth- 

 bear, which forms a genus apart (Melursus)^ there are no bears in 

 India proper, although a fossil species allied to the sloth-bear 

 occurs in the Siwaliks. This being so, when we take into account 

 the absence of ursine remains from the Pikermi and Persian beds, 

 there is nothing very wonderful in the fact that none of these 

 animals entered Ethiopia during the great Pliocene migration. 

 The absence of all Cervidce is more difficult to explain, seeing 

 that deer of an Oriental type are abundant in the Siwaliks, while 

 they are also sparingly represented in the Pikerrni beds. Typical 

 deer of the red-deer group are, however, totally wanting in the 

 Siwaliks, as they are in the Oriental region at the present day ; 

 and we are, therefore, perfectly able to account for their absence 

 from the Ethiopian region, although they occur in Africa north of 

 the Sahara. With regard to the absence of Oriental types of deer 

 in Ethiopia, it can only be said that it is as difficult to see any 

 reason why these should have continued to flourish since the 

 Pliocene in the Oriental region without ever having entered Africa, 

 as it is to explain why giraffes, hippopotami, and ostriches should 

 have disappeared from the former area to survive in the latter. 



Another difficulty is presented by the case of the pigs, bat here 

 it may be suggested that the absence of the typical group of the 

 genus Sus from the whole of Ethiopia, with the exception of 

 Sennaar, may perhaps be accounted for by all the other species of 



