186 



UNGULATA 



ORDER VII 



chenia-like in a number of characters. Lower Miocene ; western Nebraska. 

 F. typus Peterson. 



Merychyus Leidy {Ticlwleptus Cope). Muzzle shortened ; vacuity between 



Fig. 255. 



A, Promtrycochoerus macrostegus Cope sp. Skull, lateral aspect. B, Pronierycochoerus superhus Leidy sp. 

 Skull, palatal aspect. Lower Miocene (John Daj' beds), Oregon. 1/4. (After Cope.) 



lachrymal, maxillary and frontal bone. Molars hypsodont. Lateral digits 

 more reduced than in Oreodon. Middle Miocene to Pliocene. 



Leptauchenia Leidy. Dental crowns high. Muzzle shortened. Only 





'^>cZ 



Fig. 256. 



Promerycochoerus carrikeri Peteraon. Miocene, Nebraska. Group of three skeletons in rock. 1/27- 



(After Peterson.) 

 Reproiluced by permission /rom The Memoirs u/the Carnegie Museum. 



two lower incisors present. Zygomatic arch elevated. Upper Oligocene 

 (White River beds) ; North America. 



Cyclopidius Cope {Piihecistes Cope). Skull flat, and more strongly modified. 

 Premaxillary distinct, with facial vacuity. Zygomatic arch extending far 

 out from the skull. Middle Miocene (Deep River beds) ; North America. 



