PLIOLOPHUS. 359 



hog, hyrax, and palaeothere, the greatest cerebral expansion is 

 at the middle and toward the fore part of the fossae, with a 



si*-- 



Fig. 121. 

 Skull of Pliolophus vulpiceps (half nat. size), London clay. 



contraction toward the occiput ; the brain-case not continuing 

 to enlarge backward to beyond the origin of the zygomata, as 

 in the fox. The zygomatic arches ha ye a less outward span 

 than in the Carnivora. In this part of the cranial structure 

 Pliolophus resembles Palceotherium more than it does any 

 existing Mammal ; but the post-frontal processes are longer 

 and more inclined backward. The incompleteness of the 

 orbit occurs in both Anoplotherium and Palceotherium, as in 

 Rhinoceros, Tapirus, and the hog tribe ; but in the extent of 

 the deficient rim, Pliolophus is intermediate between Palceo- 

 therium and Tapirus. The orbit is not so low placed as in 

 Palceotherium, Tapirus, and Rhinoceros, nor so high as in 

 Hyrax or Bus. The straight upper contour of the skull 

 (7 to 15) is like that in the horse tribe and Hyrax, and differs 

 from the convex contour of the same part in the Anoplothere 

 and Palaeothere. The size of the antorbital foramen (a) 

 indicates no unusual development of the muzzle or upper lip. 

 In the conformation of the nasal aperture by four bones (two 

 nasals, 15, and two premaxillaries, 22), the Plioloph resembles 



