154 DISTINCT SPECIES PRESENT 



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 produced from 

 the same mare by a black Arabian Bire, 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 tliat he 

 knows of a second case) from the ass and the hemionus; 

 and this hybrid, though the ass only occasionally 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 

 Devonshire and AVelsh ponies, 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 color 

 appears from what is commonly called chance, that I was 

 led solely from the occurrence of the face-stripes on this 

 hybrid from the ass and hemionus to ask Colonel Poole 

 whether such face-stripes ever occurred in the eminently 

 striped Kattywar breed of horses, and was, as we have 

 Been, answered in the affirmative. 



What now are we to say to these several facts? We see 

 several distinct species of the horse genus becoming, by 

 simple variation, striped on the legs like a zebra, or striped 

 on the shoulders like an ass. In the horse we see this 

 tendency strong whenever a dun tint appears — a tint which 

 approaches to that of the general coloring of the other 

 species of the genus. The appearance of the stripes is not 

 accompanied by any change of form, or by any other new 

 character. We see this tendency to become striped niost 

 strongly displayed in hybrids from between several of the 

 most distinct species. Now observe the case of the several 

 breeds of pigeons: they are descended from a pigeon (in- 

 cluding two or three sub-species or geographical races) of 

 a bluish color, with certain bars and other marks; and 

 when any breed assumes by simple variation a bluish tint, 

 these bars and other marks invariably reappear; but with- 

 out any other change of form or character. When the 

 oldest and truest breed of various colors are crossed, we see 

 a strong tendency for the blue tint and bars and marks 



