THE ASININE GROUP. 299 



of creating genera for every trifling structural varia- 

 tion that may be detected. 



There is an evident tendency in both, not only to 

 approximations, but even to actual interchange of 

 some prominent external distinctions. In the wild 

 horses of Asia, a highly arched forehead and length- 

 ened ears are often very observable. We have de- 

 scribed and figured a specimen of the eelback dun 

 stock, not only marked with the spinal dark streak 

 and bars on the limbs, but actually with a cross on 

 the shoulders : again, the first species of the present 

 group will fre shown to have the head of a high-bred 

 blood-horse and the cross on the shoulders like the 

 onager, but totally different in relative proportions 

 from the Persian wild ass, which is very commonly 

 destitute of that mark. In a wild state, both groups 

 are nearly of the same size. If there be more than 

 one species domesticated in the first, so there are 

 also in the second ; all, no doubt, can and have been 

 subdued by man, and it might be suspected that 

 there has been even an intermixture sufficient be- 

 tween both, for the sympathetic action of transfer- 

 ring the marks and the livery of one to the other, 

 and in some cases perhaps to perpetuate them. 

 Excepting some slight structural characteristics, the 

 chief distinctions between the horse and asinine 

 groups evidently lie in their instinctive aptitudes ; 

 one being highly irritable and educational, with a 

 social temperament, the other dull, intractable, soli- 

 tary, seems to bear the unceasing impression of his 

 servitude alone. Like a slave, the sensual appetites 



