ITS NEAREST EXISTING RELATIONS. 79 



sembles so closely that no actual, definable difference 

 between them can be detected. In this sense we 

 may speak of Equus caballus having existed in Amer- 

 ica before its introduction by the Spaniards, although 

 it is commonly supposed that at the time of the con- 

 quest no horses, either wild or domesticated, were to 

 be found on the continent .* This is the more re- 

 markable as, when imported from Europe, the horses 

 that ran wild proved by their rapid multiplication 

 in the plains of South America and Texas that the 

 climate, food, and other circumstances were highly 

 favorable to their existence. The former great 

 abundance of Equidce in America, their extinction, 

 and their perfect acclimatization when reintroduced 

 by man, form curious but as yet unsolved problems 

 in geographical distribution. 



In Europe, wild horses were extremely abundant 

 in the Neolithic, or polished-stone period. Judging 

 by the quantity of their remains found associated 

 with those of the men of that time, the chase of these 



* The usual statement as to the complete extinction of the 

 horse in America is thus qualified, as there is a possibility of 

 the animal having still existed, in a wild state, in some parts 

 of the continent remote from that which was first visited by 

 the Spaniards, where they were certainly unknown. It has 

 been suggested that the horses which were found by Cabot in 

 La Plata in 1530 cannot have been introduced. See M. Wilck- 

 ens's "Forschungen auf dem Gebiete der Pal&ontologie der 

 Hausthiere" (Biolog. Centralblat,, 1889), 



