GEOLOGICAL SURVEY OF THE TERRITORIES. 349 



given the above name. Its principal features distinguishing it from the 

 oreodonts are as follows : 



The orbits are open behind, or not separated from the temporal fossae, 

 in which character they differ from those of all known ruminants, recent 

 or extinct, having the same form of grinding teeth. No lachrymal 

 fossse exist in front of the orbits as in the oreodonts. 



The number, relation, and general constitution of the teeth are the 

 same as in the latter ; but the grinders or true molars, though con- 

 structed on the same plan as in the oreodonts and the ruminants gen- 

 erally, are remarkable for their transversely spreading character, or the 

 comparative shallowness and breadth of their crowns. The last pre- 

 molar departs from the usual ruminant pattern, the upper having three 

 lobes to the crown, the lower four lobes. 



AGRIOCHCERTJS. 



Three species of this genus have apparently been recognized, differ- 

 ing little in size, and in this respect approaching O. Gulbertsoni. 

 The form and general construction of the skull are nearly the same as 

 in the latter. Besides the orbits being open behind, and the absence of 

 lachrymal fossae, as above mentioned, the face, in comparison with that 

 of oreodon, is proportionately wider and of less depth. The remains of 

 Agriochoerus have been discovered in the mauvaises terres of Dakota, 

 but are comparatively rare. 



Agriochoerus antiquus. — The remains of this species, consisting of frag- 

 ments of jaws and teeth, together with the facial portion of a skull, of 

 two individuals, were among the first of the mammalian fossils collected 

 in the mauvaises terres of Dakota. They were obtained from a fur 

 trader by the late Dr. Hiram A. Prout, of St. Louis, by whom they were 

 submitted to the examination of the writer. Among several tons of 

 fossil bones subsequently collected in the mauvaises terres and brought 

 to our notice, only the smallest traces of this species were detected. 



The size of the skull was about equal to that of 0. Gulbertsoni. 



Agriochcerus latifrons. — This species is indicated by an almost com- 

 plete skull, obtained by Professor Hayden, in the mauvaises terres of 

 Dakota, during his expedition of the summer of 1866. It differed little 

 in size from the preceding species, but is distinguishable by the breadth 

 of its forehead, which is almost one-third greater. Large inflated ear 

 capsules are present in the skull of A. latifrons, proportionately as well 

 developed as in 0. major. 



The skull of A. latifrons is eight and a half inches long. 



Agriochoerus major. — A somewhat larger species than the two preced- 

 ing, apparently indicated by a few fragments. 



CAMELID^E. 



The camel family at the present time is represented among the indig- 

 enous animals of the western hemisphere by the various species of 

 the lama genus of South America. During the tertiary period many 

 members of the same family were largely distributed in the western 

 part of North America. Eecently some remains discovered in Califor- \ 

 nia, and submitted to the examination of the writer by Professor J. D. 

 Whitney, indicate a species of lama exceeding in size the existing 

 camel. The species has been named Auchenia or Lama californica. 



CAMELOPS 



Is the name of an extinct genus allied to the lama, indicated by a iaw 

 fragment found in the post pliocene gravel drifts of Kansas. The species 

 is named C. Tcansanus. 



