444 THE MULTIPLE ORIGIN OP HORSES AND PONIES. 



verted to the wild state." Against this view I may mention (1) that 

 all the wild horses are of a yellow-dun color, and that, thongh those 

 to the west of Kobdo difler in tint from those to the east, the eastern 

 and western varieties seem to be connected by the less specialized 

 variety to the south of Kobdo; (2) that travelers in Central Asia 

 all agree in stating that the Mongolian i)onies vary greatly in color — 

 in a Chinese hynm known as the " Emperor's Horses " as many as 

 thirteen colors are referred to; (B) the descendants of the horses 

 wdiich escaped from the Spaniards in America after several centu- 

 ries of freedom were of all sorts of colors; and (4) in horses wdiich 

 live in subarctic areas the hair at the root of the tail tends to increase 

 so as to form a sort of tail lock, wdiich when caked with snow^ pro- 

 tects the liiud quarters during snoAvstorms; the complete absence of 

 this tail lock — fairly w^ell developed in one of my Mongolian 

 ponies — is a very strong argument against the assumption that 

 Prjevalsky's horse is notliing more than a domesticated breed that 

 has rcA^erted to the wild state. 



The w^ild horse of the Gobi Desert is certainly the least specialized 

 of all the horses living at the present day. In being of a yellow-dun 

 color, in shedding annually the hair of the mane and the hair from 

 the upper two-thirds of the tail, in liaving ergots and chestnuts on 

 the hind as well as on the fore liml)s, and in having canines and 

 fairly large upper first premolars, Prjevalsky's horse is distinctly 

 primeval. Only in the all but complete a))sence of stripes and in 

 having very long powerful jaws armed with relatively large teeth 

 can the Gobi horse be said to be specialized. 



It is extremely probable that Prjevalsky's horse w^as familiar to the 

 troglodytes Avho inhabited the Rhone Valley in prehistoric times. 

 One might even go further and say that in fig. 1, from an engraving 

 in the cave of I.a Mouthe, we have a fairly accurate representation 

 of the head of Prjevalsky's horse. 



It is, of course, impossible to sav wliich of the recent breeds are 

 most intimately related to the Gobi horse. Though the head and 

 ears are suggestive of some of the heavier occidental breeds, in its 

 trunk and limbs it more closely resembles Mongolian and Korean 

 horses, some of which, like Prjexalsky's horse, decidedly differ from 

 Shires and Clydesdales in having a small girth owing to a want of 

 depth of body. To which domestic breeds the wild horse has con- 

 tributed characters which will probably become more manifest after 

 he has lived for some time under domestication. That heavy occi- 

 dental breeds are not pure descendants of Prjevalsky's horse is sug- 



« It was formerly stated that the wild horse was simply a hybrid between a 

 Mongolian pony and a kiang. I recently showed that a hybrid of this kind is 

 quite different from the wild horse. Stv Vvoc Koy. Soc. Edin., \o\. XXIV, 

 part V, 1001*-3, and Nature, Vol. LX^'III. p. '-'71. 



