60 MEMOIRS OF THE CARNEGIE MUSEUM 
Pelonax potens (Marsh). 
Type: Greater portion of left ramus and symphysis. 
Horizon: Not indicated ; most probably upper Oligocene. 
Locality : Oligocene of Colorado. 
Locality of Type: Collection of Yale Museum, No. 12042. 
The most conspicuous feature of this type is the great development of the ante- 
rior dependent process of the inferior face of the lower jaw, which, as in Pelonax 
| ramosum, gives to the chin an unusually short and rather broad appearance. The 
alveolus for P; indicates that the roots were well” coalesced near the crown, 
a character usually found in types from the upper Oligocene, and which should be 
regarded as of subgeneric value. The antero-posterior diameter of Pz; must have 
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Fre. 14. Type of P. potens Marsh. About} nat. size. (Yale Museum, No. 12042.) 
been quite great, judging from the space which the alveolus occupies. ‘The molars 
indicate asmaller individual than Pelonax bathrodon, as stated by Marsh (68, p.,410), 
but possessing the same characters as the latter, 7. ¢, the anterior tubercles of the 
molars are higher than the posterior, and the latter separated from the former by 
broad, transverse valleys. When more complete material from the Oligocene of Col- 
orado is found, the validity of the type of Pelonax potens will be more satisfactorily 
established. 
In Pelonax ramosum P; and Py are apparently single-rooted. 
