676 
AFRICAN GAME ANIMALS 
fold or protocone of enamel is enlarged. Notwithstanding 
this similarity of structure, the various groups which are 
recognized by distinct English names have been employed 
as genera by some writers, who divide the genus up into 
zebras ( Hippotigris ), asses (Asinus), and the horse ( Equus ), 
on the basis of external differences. Unfortunately, when 
we come to consider the fossil species such differences cannot 
be employed, and we are at a loss to know whether in these 
extinct species we are dealing with zebras, asses, or horses. 
The fossil species first make their appearance in the Upper 
Pliocene and the genus continues on down through the 
Pleistocene to the present time. The former range covered 
North America, Europe, Asia, and North and South Africa, 
being absent only from South America. Recently the first 
specimen of fossil horse has been recorded from South 
Africa by Broom. It is based on some tooth remains from 
Pleistocene deposits near Cape Town, which indicate a 
very large species apparently exceeding the horse in size. 
The existing representatives occur in a small part of central 
and southern Asia and Africa. In the latter continent they 
extend from the northeastern portion southward along the 
eastern half to the Cape region and southwest coast as far 
north as Angola. The number of living representatives 
does not exceed six or seven valid species, which are com¬ 
prised in the horse, two zebras, and three or four species of 
asses. 
The Bonte-Quagga or Quagga Zebra 
Equus quagga 
Equus quagga Gmelin, 1788, Systema Naturae, p. 213. 
The name quagga has been derived from the call of the 
zebra, which consists of a short bark, kwa-ha, repeated sev¬ 
eral times. The name came originally from the Hottentot 
word quaha, through the Cape Dutch, who applied it first 
to the true quagga and later distinguished the other or more 
fully striped races as bonte-quaggas. The quagga has by 
most recent writers been considered a distinct species from the 
Burchell zebra and its northern races owing to the restriction 
in the quagga of the stripes to the forward part of the body. 
It is, however, less widely separated in coloration from the 
