PREJEVALSKI'S WILD HORSE 393 



other external features may be, a belief which has generally 

 and rightly been accepted since Darwin's time. It is incon- 

 ceivable to think of functional identity in two such complex 

 organisms as the procreative parts of two types of horses 

 being maintained indefinitely when it is seen that the ass, the 

 horse, and the zebra, although also derived in the very remote 

 past from a common parentage, are incapable of producing 

 fertile hybrids. Darwin thought that the original colour of 

 the wild horse was dun, but Ridgway finding no dun-coloured 

 specimens in the superior type of Libyan bay horse, adopts 

 the view that the progenitors of the Libyan horse have had a 

 line of descent different from that of all other horses and 

 ponies. He says : " It will be observed that those who hold 

 a single origin for all domesticated horses base their belief on 

 the fertility of the most distinct breeds when crossed. Yet 

 this cannot be regarded as a true criterion, for animals which 

 are admittedly distinct species, such as the dog, the wolf, and 

 the jackal among carnivora, and the common ox, the zebu, Bos 

 gaurus, and the yak, Bos grunniens, among herbivora, freely 

 interbreed and produce fertile offspring." Such an unlikely 

 suggestion is, from a practical point of view, a blemish in a book 

 that, from the historical and archaeological side of the question, 

 must rank as the foremost work in English on the subject. 



Prejevalski's wild horse, Equus przewalskii (Poliakof), is 

 now admitted to be the only genuine wild horse. 1 It was 

 heard of in the deserts of Central Asia by the famous 

 traveller whose name it bears, and it was first described by 

 Poliakof in 1881. Its present known habitats lie almost in 

 the centre of Asia, in the Gobi Desert, and in a rectangular 

 space of moderate dimensions on the north-west border of 

 Mongolia in the vicinity of the Altai Mountains, bounded west 

 and east by long. 84 and 90 to 91, and north and south by 

 lat. 48 and 46. Four varieties of the type are reported to exist, 

 with different shades of colour of hair. In 1902 Carl Hagen- 

 beck of Hamburg (under commission for the Duke of Bedford) 

 succeeded by the help of about 2000 Kirghis in securing 32 



1 In a paper read before the Royal Society of Edinburgh on 6th 

 November 1905, Cossar Ewart draws attention to the existence of five 

 lumbar vertebras in the wild horse in place of six in our domesticated 

 breeds, as evidence connecting it with the wild Tarpan of Central Asia. 



