ORDER UNGULATA. 



1335 



of the same area, the incisors were reduced (as in all the other forms) 



to -, but there were still four premolars, although the first is isolated 



3 

 and the second very small. Pliauchenia (which is perhaps identical 

 with Homocamelus) has only three lower premolars, and occurs in the 



Fig. 1209. — Left lateral view of the skull of the Camel {Camelus bactrianus). Reduced. 

 i, Upper incisor ; c, c, Canines ; pm, Isolated premolar. The maxillo-premaxillary suture should 

 have been placed in front of c instead of in front of pm. 



Loup-Fork-beds of North America. In Camelus again (fig. 1209) 



the normal adult formula of the cheek-teeth is Pm. vl, M. - ; the 



X 3 

 first upper premolar being canine-like, and separated by a long 

 interval from the penultimate tooth of that series. This genus is 

 confined to the Old World ; the earliest known species occurring in 

 the Pliocene of India, and another form (C. Thomasi) in the Pleisto- 

 cene of Algeria. The molars of the Siwalik species show characters 

 now only found in Auchenia. The latter generic term is here taken 



Fig. 1210. — A, First left lower true molar of Auchenia hesterna, Pleistocene, California; B, 

 Fourth right upper premolar and first true molar of Procamelus virgifiiensis, Miocene, North 

 America ; c, Third right lower true molar of do. 



to include a number of fossil New World forms some of which 

 have been generically separated under the names of Hemiauchenia 

 Palauchenia, P?'otauchenia, If olo meniscus, and Eschatius. In the 

 vol. 11. 2 F 



