CHAPTER III. 



THE AFRICAN WILD ASS. 

 {Equus asinus. Idnn.) 



The two species of the genus Equus, namely Equus 

 caballus and Equus przewalskii, are both regarded as horses, 

 being distinguished, amongst other characters, by the 

 presence of callosities, also known as ergots, chesnuts, or 

 castors, on both the hind and fore legs ; these are absent 

 from the hind legs of the other species, whilst some of 

 the hybrids (mules) have them, and others have not — by 

 their broad hoofs, and by the long hair not being confined 

 to the extremity of the tail. 



The remaining equine animals may conveniently, though 

 not with any great accuracy, be divided into two groups, 

 those which are plainly coloured, the true asses, and those 

 which are striped, and are known popularly as zebras. 



The distinction, though obvious to the eye, has no great 

 zoological value. Several of the varieties of the horse, 

 such as the pure bred Norwegian ponies, habitually have 

 the spinal and leg stripes, and numerous other breeds that 

 possess them are described by Darwin in his work on 

 "Variation,'^ and one African ass, that from Somaliland, is 

 characterised by its transverse leg stripes. The asses are, 

 however, characterised by their geographical distribution, 

 those from Africa being markedly distinct from the Asiatic 

 species. 



