TELEGONY AND REVERSION. 113 



the ancestral horse resembled that of the zebra of to-day 

 may also be gathered from a study of its development. In 

 the embryo the tail is at the outset not only quite hairless, 

 but much longer than the hind limbs. By-and-by the limbs 

 grow so rapidly that the tail hardly reaches as far as the 

 hocks. At about the eighth month of foetal life the tail 

 (with the exception of its tip) is covered with quite short 

 hairs ; the tip has already longish hairs. In fact, the 

 history of the development of the tail, as far as made out, 

 seems to indicate that in the remote ancestors of the horse 

 there were long hairs at the apex only, as in the Somali 

 zebra ; that in less remote ancestors less long but deci- 

 duous hairs extended up to within a short distance (six or 

 seven inches) of the root, as in the Burchell zebras ; and 

 that eventually, as the hair began to persist in the mane,, 

 persistent hairs appeared up to, or almost up to, the base 

 of the tail, as in our recent horses. 



What answer shall we now give to the question : Have 

 our horses descended from striped ancestors ? Taking 

 into consideration the facts I have mentioned, and espe- 

 cially (1) that there are more or less striped horses in all 

 parts of the Old World; "^ (2) that in Mexico and various 

 other parts of the New World the descendants of horses 

 introduced by the Spaniards are frequently dun-coloured 

 and provided with dorsal and leg stripes ; t (3) that foals 

 are often partially striped, one bred by Darwin being 

 marked all over with obscure narrow stripes ; and (4) 

 that mules (hybrids between the jackass and mare) have 

 frequently leg stripes as well as spinal and shoulder 

 stripes — taking these and other facts into considera- 

 tion, the conclusion may be hazarded that the ancestors 

 of all our horses were striped, and that the stripes 

 were arranged more after the plan in the common than 

 in that of the Burchell zebra. If we agree with Darwin 

 "that not even a stripe of colour appears from what is 



* See ' Animals and Plants,' vol. i, p. 61. 

 t Nature, March lltb, 1897. 



