16 



CATALOGUE OF UNGULATES 



large and somewhat elongated ; skull long and narrow, 

 especially the muzzle, in which the diastema is equal to the 

 combined basal length of the last four cheek-teeth ; lambdoid 

 crest of occiput produced behind line of condyles, and 

 extending almost on a level with the auditory meatus, instead 

 of being vertically above it as in the subgenera Equv.s and 

 HipiMifjris ; lachrymal large, forming one-third of orbital 



Fig. 8.— Head of Gbevy's Zebra {Equus [Dolichohipjms] grevyi). 



rim ; ascending process of premaxilla narrow ; palatal fora- 

 mina long and narrow ; brain-case shallow^ and depressed. 



Heller remarks that in general shape the skull approxi- 

 mates to that of U. caball'iis, but that in its extreme eloncfa- 

 tion and narrowness it differs from all the other members of 

 the family ; the horse occupying in this respect a position 

 intermediate between the present species on the one hand 

 and the quagga, zebra, and ass on the other. 



The range is restricted to north-eastern and eastern 

 Ethiopian Africa. 



