CH. Ill] EVOLUTION AND DISTRIBUTION. 131 



larities. It is a matter for the greatest wonder why the 

 old world monkeys have not got prehensile tails. 



On the other hand the similarity of the faunas of 

 tropical countries even when widely separated have some- 

 times another explanation. The tapirs of America and 

 India are unquestionably allied. They are purely tropical 

 animals and yet separated by a stretch of land which is 

 not tropical. But in earlier periods of the earth's history 

 we know that Europe was favoured with a higher tempe- 

 rature than at present ; we also find the bones of tapirs 

 in Europe at that period ; hence the inference that the 

 tapir has been isolated in its present habitats by the 

 gradual decrease of heat in the northern hemisphere. 



These few examples again show how needful it is for 

 the student of Zoogeography to have a thorough acquaint- 

 ance with the structure of animals ; he must be able to 

 distinguish between merely adaptative resemblances and 

 real structural similarities. 



Problems of Distribution and Evolution. 



It is not necessary now to argue against the doctrine 

 of special creation ; evolution in some form or other is 

 almost universally accepted ; and the facts of distribution, 

 as Darwin himself showed in great detail, are among the 

 most convincing proofs of the untenability of any such 

 belief as special creation. We have for instance remote 

 islands, such as the Azores, which are quite capable of 

 supporting mammalian life, as has been abundantly proved 

 by the flourishing condition of purposely or accidentally 



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