10 THE HORSE BOOK. 



and directly in the line of the supposed migra- 

 tion that what is considered to be the wild type 

 of horse was discovered by Prjevalsky, a Eus- 

 sian traveler. Since 1881 several specimens of 

 this species have been brought into captivity 

 and its habits studied in the region to which it 

 is indigenous. This species attains a height of 

 from 12 to 13 hands. Between Pliohippus and 

 the Prehistoric horse there is a gap in the line 

 of descent differently filled by various authori- 

 ties. It was at this period that the genus 

 branched into the 'three species now represented 

 by the horse, the ass and the zebra. 



Of the Prehistoric horse we read the record 

 in his fossilized bones found in caves, left there 

 by the men of the Older Stone Age, the Newer 

 Stone Age and the Bronze Age. Horses seem 

 then to have been used only as human food and 

 it cannot be determined when they were first 

 made subservient to the will of man to carry 

 him or to work. Some of the Prehistoric horses 

 partook largely of the character of the ass and 

 it is probable that Prjevalsky 's horse corre- 

 sponds quite closely to some of the later forms 

 of that step in equine evolution or forms a sort 

 of a connecting link between the Prehistoric and 

 the Historic races. 



Scientifically the horse, the ass and the zebra 

 form what is known as the genus Equus. The 

 Nubian Wild Ass is the nearest the original 

 type of ass and from it all our domesticated 



