INTRODUCTION. 73 



quently with cross bars on the joints : but thi con- 

 jecture would not account for the stripes on th^ neck 

 and shouklers, and though far fetched, explains only 

 the dorsal streak and bars on the limbs, which the 

 Eelback dun seems to have derived from an ancient 

 cross with Hcmionus, for this race of horses is nearest 

 in colour and markings to the Isabella breed of 

 antiquity, so renowned for mounting the Median 

 cavalry, and not always destitute of a cross on the 

 shoulder. 



Whether one or more species of wild horses con- 

 stituted the primaeval forms of the distinct races of 

 the northern half of Asia, and merged gradually into 

 the Equus caballus of systematic writers, is a question 

 not likely to be fully determined, but beside them 

 there are at least two other Equidse, one ranging 

 over the Steppes of Tahtary, and from thence south- 

 ward to the plains of Persia, is known by the names of 

 Hemionus and Dziggetai, and the other a more south- 

 ern animal, though ascending in summer as far north 

 as Lake Aral, is questionably regarded as the original 

 wild ass, and bears the names of Hymar, Ghoor-Khar 

 and Kulan ; while a third, the Kiang of Ladauk, is 

 not as yet sufficiently described, and a fourth more 

 nearly allied to Hemionus, probably the Yo-to-tze of 

 China, will be noticed by us under the appellation of 

 Asinus Hippagrus. All these species or varieties have 

 been confounded by travellers and naturalists until 

 their names and distinctive marks cannot becompletely 

 rectified. There exists besides in the northern half 

 of Africa an Equine animal designated by the natives 



