Il] THE EXISTING EQUIDAE 39 



difference of considerable importance is, that while the wild 

 horse neighs, the hybrid makes a peculiar barking sound 

 remotely suggestive of the rasping call of the Kiang. 



" The dun Mongol pony's hybrid arrived five weeks before 

 its time, and, though perfect in every way, was short-lived. 

 Only in one respect did this hybrid differ from the one already 

 described. In the Ex moor hybrid the hock callosities are 

 entirely absent ; in the Mongol hybrid the right hock callosity 

 is completely wanting, but the left one is represented by a 

 small, slightly hardened patch of skin, sparsely covered with 

 short white hair. In zebra hybrids out of cross-bred mares 

 the hock callosities are usually fairly large, while in hybrids 

 out of well-bred pony mares the hock callosities are invariably 

 absent. The Exmoor 1 pony, though not as pure as the Hebri- 

 dean and other ponies without callosities, has undoubtedly 

 a strong dash of true pony blood; the Mongol pony is as 

 certainly saturated with what, for want of a better term, may 

 be called cart-horse blood." 



Prof. Ewart thus sums up the results of his experiment : 

 " From what has been said, it follows that a Kiang-Mongol pony 

 hybrid differs from Prejvalsky's horse (1) in having the merest 

 vestiges of hock callosities ; (2) in not neighing like a horse ; 



(3) in having finer limbs and joints and less specialized hoofs ; 



(4) in the form of the head, in the lips, muzzle, and ears; 



(5) in the dorsal band ; and (6) in the absence even at birth 

 of any suggestion of shoulder stripes and of bars on the legs." 



After this experiment it does not seem likely that zoologists 

 will continue to hold that Prejvalsky horses are the offspring 

 of Kiangs and feral Mongolian ponies 2 . 



But as some naturalists had maintained that Prejvalsky 

 horses in nowise differed essentially from an ordinary horse 

 and held that the colts brought from Central Asia were the 

 progeny of escaped feral Mongol ponies, and as others again 

 asserted that they failed to discover any difference between the 



1 The Exmoor ponies are said to have derived some good blood from a 

 famous stallion Katerfelto. 



2 As these pages are passing through the press the Prejvalsky horses belong- 

 ing to the Duke of Bedford have themselves triumphantly refuted the charge of 

 their being merely mules by having this year (1904) produced offspring. 



