CHAPTER XXIII 
THE GREVY ZEBRA 
Dolichohippus 
Dolichohippus Heller, 1912, Smith. Misc. Coll., vol. 60, No. 8, p. 1; type 
D. grevyi . 
The striped horses, or zebras, have been associated 
by some naturalists 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 
Equidce. 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 
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