284: Loomis — Wasatch and Wind River Primates. 



The fourth premolar has but a trace of au external cingulurn 

 and a well developed posterior cingulurn on which two cusps 

 are developed, the larger to the outer side. On the molars 

 there is also but a trace of an external cingulurn. The last molar 

 has the hypoconid and entoconid about equally developed and 

 a small medianly placed heel on which there is a moderate 

 hypoconulid. 



The species differs from N. cingidatus in the lack of the 

 cingulurn and in the median position of the heel on molar 3. 

 While eleven specimens were found, they are mostly very 

 fragmentary, the jaws being extremely fragile. The three 

 lower molars measure H mm in length and 2*7 mm in width. 



Fig. 7. Notharctus palmert, type, x 8. A, the fourth premolar of the 

 left side ; B, molars 2 and 3 of the right side. 



Fig. 8. Notharctus cingulatus. type, x 3. A, premolar 4 and molars 2 

 and 3 of the right side ; B, molar 3 of the left side. 



Notharctus cingulatus sp. nov. 



This second small form is about equally abundant with the 

 foregoing in the Wind River beds of Bridget' Creek. The 

 type is a right mandibular ramus containing the fourth pre- 

 molar and molars 1 and 2. With it is associated a third molar 

 of the left side which may belong to the same individual. 



While similar to the foregoing, the species is distinctive in 

 that the fourth premolar has a complete external cingulurn, 

 and the posterior cingulurn is simply raised medianly into a 

 cusp-like process. Molars 1 and 2 have an almost complete 

 external cingulurn. The last lower molar has the hypoconid 

 larger than the entoconid ; and the small hypoconulid on a 

 small heel, placed toward the inner side of the tooth. 



Twelve specimens of this species were found on Bridger 

 Creek. The three lower molars measure together H mm in 

 length and 2'7 mm in width. 



Notharctus venticolus Osborn.* 



This is a larger species founded by Osborn on the Wind 

 River specimens which Cope had associated with P. tutus. 

 None were found in the Bridger Creek locality. The three 

 lower molars measure 17 mm in length. 



Amherst Biological Laboratory. 



*Bull. Amer. Mus. Nat. Hist., vol. xvi, 1902, p. 195. 



