250 THE HORSES OF PREHISTORIC [OH. 



the finest; they have all white legs (Fig. 73), sometimes the 

 white extending over the thighs and occasionally over the belly 1 . 



We have seen at an earlier stage that the presence or 

 absence of hock callosities has been generally taken as one of the 

 chief means of differentiating Equus caballus from the asses and 

 zebras (p. 16). It is therefore to be carefully noted that, whilst 

 the hock callosities are present in Prejvalsky's horse, and are 

 of specially large size in domestic horses of heavy breeds, accord- 

 ing to Sanson 2 they are frequently absent in North African 

 horses (as is the case with Ewart's 'Celtic' pony). The presence 

 therefore of such hock callosities in Arab horses of a coarser type 

 may be due to their having in their veins a considerable ad- 

 mixture of Asiatic blood, as is certainly the case with many 

 'Arabs' from Turkish Arabia, and the tribes of South Arabia, 

 which border on the Persian Gulf (pp. 183-6). 



It has already been pointed out that white feet and a star 

 or blaze on the forehead are characteristic of the pure Anazah 

 bay horses, and it has also been shown that the fine black 

 horses with white feet the best bred by the Turcomans are 

 the result of crossing the horses of Upper Asia with so-called 

 Arab blood (p. 133), that black horses are never found in 

 Al Khamseh, and that the best black horses found in Syria 

 belong regularly to the Jelfon breed; it has also been shown 

 that the 'Arab ' horses sent in large numbers into Egypt are 

 exported from Syria, where a large proportion of the horses are 

 grey, such horses being the result of crossing common Turcoman 

 mares with pure Arab horses. It is therefore more than 

 probable that all the black, grey, and white horses of North 

 Africa have been derived either from Syrian and other horses 

 of impure breed, or else have resulted from the blending in 

 Africa itself of Asiatic and European horses with a native dark 

 breed. As we have already seen that there were no horses in 

 all North-east Africa or in Nubia down to the time of Strabo, 



1 Hamilton Smith, op. cit. pp. 229-30, PI. 10*, from which my illustration 

 is copied. 



2 Zootechnie, Vol. in. p. 53 (ed. 4). Under the heading of "caracteres zoo- 

 techniques generaux" he says that "les membres poste'rieurs sont depourvus de 

 chataignes" in the "Eace africame" (E. c. africanus). 



