ORDER UNGULATA. 



327 



the manus. In Eporeodoji, or Eucrotaphus^ the above characters 

 are the same, with the exception that the tympanic bullae are in- 

 flated ; while Merycochcerus differs from the latter by the anchylosis 

 of the premaxillae. There are seven species in the latter, genus. 

 Merychyns is distinguished from Merycochoerus by the presence 

 of vacuities in the lachrymal region. In Leptauchenia, which has 

 been placed by some writers in the Camelidce, such vacuities occur 



Fig. 1202. — Frontal (1) and left lateral (2) aspects of the cranium of Cyclopidius emidinus ; 

 from the Miocene of the United States. Reduced. (After Cope.) 



close to the frontals, and the nasals become very small. Still more 

 remarkable is the enormous development of these vacuities in Cyclo- 

 pidius (fig. 1 202), in which the upper incisors are wanting. Pithecistes, 

 again, differs from all the preceding by the absence of the first pre- 

 molar, and has but one pair of lower incisors. In the second divi- 

 sion of this family, which includes the genera Agriochozrus and 

 Coloreodon, the orbit is incompletely surrounded by bone, and the 



