CHAPTER XXIII 



THE GREVY ZEBRA 



Dolichohippus 



Dolichohippus Heller, 191 2, Smith. Misc. Coll., vol. 60, No. 8, p. i; type 

 D. grevyi. 



The Striped horses, or zebras, have been associated 

 by some naturaHsts in a genus Hippotigris, a name by 

 which they were known to the ancient Romans. Be- 

 yond their striped coats, however, they have no other 

 common character separating them from other existing 

 Equidcs. This assemblage illustrates well the popular idea 

 that all the striped horses are closely related. As a matter 

 of fact, they differ more among themselves than they do 

 from either asses or the domestic horse. In this connec- 

 tion it may be well to call attention to the probability of 

 many of the fossil horses having had striped coats and their 

 probable close relationship with some of the African zebras 

 rather than the horse. One, at least, of the living striped 

 horses we believe deserves generic rank. The Grevy zebra 

 stands out in shape of skull and proportions of head and 

 body further from the other zebras and asses than does the 

 horse, which is commonly regarded as the most highly 

 specialized member. Considering the large number of 

 fossil species, it is of some advantage to discriminate as 

 finely as possible between the few existing species so as to 

 show their probable relationships to such forms by means 

 of distinct generic names. The enlargement of the head in 



G98 



