22 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 9i 



ing cusps, which appear to be somewhat more acute, although this 

 tooth in the type of O. simplex is rather well worn. The tooth, 

 No. 16217, measures 4.8 mm. anteroposteriorly across the styles and 

 5.2 mm. transversely. 



Oxyclaenid? 



An isolated upper molar, possibly M^, No. 15546, in the 1937 col- 

 lection from the Dragon level, may be from an oxyclaenid type of 

 carnivore. The tooth is too large to belong to Owycl-aenus pearcei 

 and differs somewhat from the Oxyclaenus type of tooth. Although 

 exhibiting a parastyle, the external angles are not so acute as in 

 either Oxyclaenus or Chriaoiis. The hj^pocone is more lingual than 

 in Oxyclaenus and a slight protostyle is present at the lingual ex- 

 tremity of the anterior cingulum. The hypocone, however, is not 

 developed as in ChHacus^ the cusps in general are more nearly 

 conical, and the cingulum does not extend entirely across the lingual 

 wall of the protocone. Moreover, the protoconule and metaconule 

 are more distinctly separated from the outer cusps than in any of 

 the oxyclaenid material examined. 



Some resemblance is seen between this tooth and M- in the con- 

 dylarth Dracoclaenus griphus^ with which it corresponds closely in 

 size, but there is no mesostyle, the hypocone is more lingual in posi- 

 tion, there is a slight protostyle, and, as in comparison with the 

 oxyciaenids, the protoconule and metaconule are too widely separated 

 from the paracone and metacone, respectively. 



The anteroposterior diameter of the tOiOth is about 6.2 mm. and 

 the transverse diameter 7.6 mm. 



Genus TRICENTES Cope 



TRICENTES ELASSUS," new species 



Type.—\J^])Qv molar, M\ U.S.N.M. No. 16178. 



Horizon and locality. — Dragon Paleocene, Dragon Canyon, Emery 

 County, Utah. 



Specific characters. — ^A little smaller than Tricentes subtrigonus. 

 Cusps and outer angles of upper molars somewhat more acute. Cingu- 

 lum does not extend around lingual wall of protocone on M^ 



Description. — At least three isolated upper molars and a lower 

 molar in the Dragon collection are recognized as belonging to Tri- 

 centes. The upper molars are a little smaller than in material referred 

 to Tricentes c7'assicolidens and about a fifth smaller than in the type 

 of Tricentes subtrigonus; however, certain specimens from the Tor- 

 re j on are nearlj^ as small as the Dragon form. The outer angles of 

 the upper molars are somewhat more acute, and the cusps in general 



"'tXafftrwy, small, in allusion to its size. 



