SUBORDER B 



HYEACOIDEA 



249 



account of the structure of the incisors and the form of the skull. Cuvier 

 pointed out the similarity of the teeth and extremities to those of rhinoceros,. 



Fig. 332. 



Arsinoitherium zilteli Tiea,dnel\. Oligocene, Fayum, Egypt. J, Skull and lower jaw, 1/9. 

 B, Upper cheek teeth. C, Lower cheek teeth, 2/g. (After Andrews.) 



and Cope instituted the order Taxeopoda for the reception of Hijrax and other 

 ungulates on account of the serial order of the carpals. 



The Hyracoidea are subdivided into the families Ilyracidae, Saghatheriidae, 

 and Myohyracidae. 



1.0.4.3. 



Family 1. Hyracidae Gray. 



^ ^ , ^ Premolars molariform and like the molars are hrachxiodont and 

 2.0.4,3. •' 



lophodont. Upper molars with ^-shaped edoloph and two oblique ridges. Lower 



molars consisting of two crescents. Boof of the skull flat, snout short. 



The Hyracidae inhabit the southern and eastern portions of Africa, Arabia 

 and Syria. Fossil forms are not known. They are distinguished from the 

 Saghatheriidae not only by their small size but also by the flattened roof of the 

 skull ; by the orbits being placed far forward and usually closed posteriorly ; 

 by having two temporal crests in place of one sagittal crest ; and by the 



