Chap. V. 
LAWS OF VARIATION. 
165 
crosses with the dun stock. But I am not at all satisfied 
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, &c., inhabiting the most 
distant parts of the world. 
Now let us turn to the effects of crossing the several 
species of the horse-genus. Eollin 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 
legs 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 be¬ 
tween 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 
produced 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, 
nevertheless had all four legs barred, and had three 
short shoulder-stripes, like those on the dun Welch 
pony, and even had some zebra-like stripes on the 
sides of its face. With respect to this last fact, I 
was so convinced that not even a stripe of colour 
appears from what would commonly be called an acci- 
