American Big Game in its Haunts 



ancestor of the prong-horn; or we may prefer to 

 believe that the differentiation took place earlier in 

 Europe or Asia, from ancestors common to both. 

 But there is a serious dilemma. If we choose the 

 former view, we must conclude that the deciduous 

 antler was independently developed in each of the 

 two continents, and while it is quite probable that 

 approximately similar structures have at times 

 arisen independently, it is not easy to believe that 

 an arrangement so minutely identical in form and 

 function can have been twice evolved. On the 

 second supposition, we have to face the fact that 

 there is very little evidence from palaeontology of 

 the former presence of the American type in 

 Eurasia. But, on the whole, the latter hypothesis 

 presents fewer difficulties and is probably the cor- 

 rect one; in which case two migrations must have 

 taken place, an earlier one of the generalized type 

 to which Blastomeryx and Cosoryx belonged, and 

 a later one of the direct ancestor of Mazama. 

 There is little difficulty in the assumption of these 

 repeated migrations, for evidence exists that 

 during a great part of the last half of the Tertiary 

 this continent was connected by land to the north- 

 west with Asia, and to the northeast, through 

 Greenland and Iceland, with western Europe. 

 The distinction between the two groups is well 

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