LAWS OF VARIATION 149 



to Eastern China ; and from Norway in the north to the 

 Malay Archipelago in the south. In all parts of the 

 world these stripes occur far oftenest in duns and mouse- 

 duns ; by the term dun a large range of colour is in- 

 cluded, from one between brown and black to a close 

 approach to cream-colour. 



I am aware that Colonel Hamilton Smith, who has 

 written on this subject, believes that the several breeds 

 of the horse have descended from several aboriginal 

 species — one of which, the dun, was striped ; and that 

 the above-described appearances are all due to ancient 

 crosses with the dun stock. But I am not at all satis- 

 fied with this theory, and should be loth to apply it to 

 breeds so distinct as the heavy Belgian cart-horse, 

 Welch ponies, cobs, the lanky Kattywar race, etc., in- 

 habiting the most distant parts of the world. 



Now let us turn to the effects of crossing the several 

 species of the horse -genus. Rollin asserts, that the 

 common mule from the ass and horse is particularly 

 apt to have bars on its legs : according to Mr. Gosse, in 

 certain parts of the United States about nine out of ten 

 mules have striped legs. I once saw a mule with its I 

 so much striped that any one would at first have thought 

 that it must have been the product of a zebra ; and 

 Mr. W. C. Martin, in his excellent treatise on the horse, 

 has given a figure of a similar mule. In four coloured 

 drawings, which I have seen, of hybrids between the 

 ass and zebra, the legs were much more plainly barred 

 than the rest of the body ; and in one of them there 

 was a double shoulder-stripe. In Lord Morton's famous 

 hybrid from a chestnut mare and male quagga, the 

 hybrid, and even the pure offspring subsequently pro- 

 duced from the mare by a black Arabian sire, were 

 much more plainly barred across the legs than is even 

 the pure quagga. Lastly, and this is another most 

 remarkable case, a hybrid has been figured by Dr. Gray 

 (and he informs me that he knows of a second case) 

 from the ass and the hemionus ; and this hybrid, 

 though the ass seldom has stripes on his legs and the 

 hemionus has none and has not even a shoulder-stripe, 



