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white-tailed deer, is tliat in the one case it occnrs in desert>-hannting and in the 

 other in forest-dwelling types. Some other cause than protective resemblance must 

 apparently therefore be connected with the change in at least one of the two cases ; 

 as what holds good in regard to protective resemblance of this nature in the case of 

 forest animals can scarcely also obtain in the case of desert forms. Possibly the 

 seasonal colour-change in the smaller Asiatic wild asses may be a feature inherited 

 from forest-dwelling ancestors. In any case, the kiang seems to have almost 

 discarded snch a seasonal change of colour — perhaps in special harmony with its 

 surroundings, which in parts of Ladak, at any rate, show a predominance of red 

 tints. It is further noteworthy that the colour of the kiang approximates to what 

 we may probably regard as the ancestral colour of the horse — namely, the rufous 

 dun, with black points and a white muzzle, displayed by the Mongolian wild 

 pony. 



So close, indeed, does the kiang come to tlie horse, that it seems to me 

 impossible to refer the two species to separate subgenera. On the other hand, 

 the former animal appears to be intimately connected, through the chigetai, with 

 the ghor-khar and onagers. Consequently the proposed reference of the horse to 

 the subgenus Equus, and the separation of the asses as a second subgenus {Asinus), 

 seem no longer logical. 



I. THE CHIGETAI, OR KIANG. 

 Equus hemionus. 



Equus hemioiiua, Pallas, Noi: Comm. Petmp., vol. six. p. 395, pi. vii. (1775). 



Hab. Mongolia and Turkestan, ranging northwards to Transbaikalia and 

 westwards to Transcaspia. 



Size large, the height at the shoulder reaching to 4 ft. 3 in. Ears (in 

 comparison with those of E. nsimis) relatively small and horselike. Hoofs 

 large and broad, the width of the front ]>air markedly exceeding that of the hind 

 ones. Tail-tuft large, and a slight rudiment of a forelock present. Dark dorsal 

 stripe relatively narrow, reaching the tail-tuft, and (in most cases at any rate) 

 not bordered with white. No shoulder-stripe, or dark barrings on the limbs ; a 

 dark ring immediately above the hoofs. General colour of upper-parts, in summer 

 coat, varying from Ijright rufous chestnut (with a more or less marked tinge of 

 greyish fawn on the neck) to reddish sandy ; muzzle, inside of ear, throat, under- 

 parts, inner side of legs, and a streak on the buttocks, pure white or huffish white. 

 In the long winter coat tiie general colour apparently not distinctly grey, although 

 greyish in the typical form. Cry, a " shrieking bray." 



The skull of the kiang differs markedly from that of the onager, but from lack 

 of specimens of that of the chigetai, I am unable to give the cranial characters 

 of the species as a whole. 



I have experienced great difficulty in deciding whether to regard the chigetai 

 and the kiang as a species by themselves, or to include under the same specific title 

 the ghor-khar and the onagers. 



The ;kiang, as is well shown by comparing the mounted specimen in the 

 British Museum with the example of the Somali wild ass standing in the 

 same case, is characterised by the great width of the hoofs, more especially the front 



