Chap. XIII. 



EEVERSION, 



17 



that the ass aids in gi^^ng, through the power of reversion, this 

 character to its hybrid offspring. 



The quagga is banded over the whole front part of its body like 

 a zebra, but has no stripes on its legs, or mere traces of them. Bnt 

 in the famous hybrid bred by Lord Morton,^^ from a chestnut, 

 nearly purely-bred, Arabian mare, by a male quagga, the stripes 

 were " more strongly defined and darker than those on the legs of 

 " the quagga." The mare was subsequently put to a black Arabian 

 liorse, and bore two colts, both of which, as formerly stated, were 

 plainly striped on the legs, and one of them likewise had striiDes on 

 the neck and body. 



The Equus indicus^^ is cliaracterised by a spinal stripe, without 

 shoulder or leg stripes; but traces of these latter stripes may occa- 

 sionally be seen even in the adult ;^^ and Colonel S. Poole, who has 

 had ample opportunities for observation, informs me that in the 

 foal, when first born, the head and legs are often striped, but the 

 shoulder-stripe is not so distinct as in the domestic ass ; all these 

 stripes, excepting that along the spine, soon disappear. Now a 

 hybrid, raised at Knowsley^^ from a female of this species by a 

 male domestic ass, had all four legs transversely and conspicuously 

 striped, had three short stripes on each shoulder and had even some 

 zebra-like stripes on its face! Dr. Gray informs me that he has 

 seen a second hybrid of the same parentage similarly striped. 



From these facts we see that the crossing of the several equine 

 species tends in a marked manner to cause stripes to appear on 

 various parts of the body, especially on the legs. As we do not 

 know whether the parent-form of the genus was striped, the appear- 

 ance of the stripes can only hypothetically be attributed to reversion. 

 But most persons, after considering the many undoubted cases of 

 variously coloured marks reappearing by reversion in my experi- 

 ments on crossed pigeons and fowls, will come to the same conclu- 

 sion with respect to the horse-genus; and if so, we must admit 

 that the progenitor of the group was striped on the legs, shoulders, 

 iace, and probably over the whole body, like a zebra. 



Lastly, Professor Jaeger has given ^^ a good case with pigs. He 



^^ ' Phiiosoph. Transact.,' 1821, p. 

 20. 



^^ Sclater, in ' Proc. Zoolog. f'yC.,' 

 1862, p. 163: this species ij the 

 Ghor-Khur of N.W. India, and has 

 often been called the Hemionus of 

 Pallas. See, also, Mr. Blyth's ex- 

 cellent paper in ' Journal of Asiatic 

 Soc. of Bengal,' vol. xxviii., 1860, p. 

 229. 



^' Another species of wild ass, the 

 true U. hemiomis or Kiang, which 

 ordinarily has no shoulder-sti'ipes, is 

 said occasionally to have them ; and 



these, as with the horse and ass, are 

 sometimes double : see Mr. Blyth, in 

 the paper just quoted, and in 'Indian 

 Sporting Keview,' 1856, p. 320: and 

 Col. Hamilton Smith, in 'Xat. Library, 

 Horses,' p. 318; and 'Diet. Class. 

 d'Hist. Nat.,' tom. iii. p. 563. 



^^ Figured in the ' Gleanings from 

 the Knowsley Menageries,' by Dr. J. 

 E. Gray. 



^^ ' Darwin'sche Theorie und ihre 

 Stellung zu Moral und Keligion,' ji, 

 85. 



