68 



THE HORSE 



American general called Merychippus and Protohippus, 

 without the intervention of the special characteristics 

 of hipparion ; but, unfortunately, of many of these forms, 

 the bones, and especially those of the limbs, are known 

 very imperfectly or not at all. There is, however, al- 

 ready enough to show that it is by no means impossible 

 that America may have been the cradle of all the 

 existing Equidce, as it seems to have been of such 

 apparently typical Old World forms as rhinoceroses and 

 camels, and that they spread westward by means of 

 the former free communication between the two conti- 

 nents in the neighbourhood of Behring's Straits, and, 

 having prevailed over the allied forms they found in 

 possession, totally disappeared from the country of their 

 birth until re-introduced by the agency of man. This 

 supposition, based upon the great abundance and variety 

 of the possible ancestral forms of the horse which have 

 lately been discovered in America, may be at any time 

 negatived by similar discoveries in the Old World, 

 the absence of which at the present time cannot be taken 

 as any evidence of their non-existence. 



In a popular exposition of this subject it would be 

 out of place to give an account of the views, more or 

 less crude, which have been put forth by the various 

 zoologists who have lately exercised much labour, 

 patience, and thought in endeavouring to investigate 

 the exact lines of descent of the different species and 



