24 PROCEEDINGS OF THE NATIONAL MUSEUM vol.91 



but it appears as if this portion may not have extended so far antero- 

 posteriorly as in G. levisanus. 



The anteroposterior diameter of the upper molar, No. 16207, cannot 

 be measured, but the transverse diameter is about 9 mm. 



Genus DIDYMICTIS Cope 



DIDYMICTIS? species 



A fourth lower premolar, U.S.N.M. No. 15763, apparently repre- 

 sents the genus Didymictis. The tooth is only slightly smaller than 

 in Didymictis haydenianus from the Torre j on but does not have the 

 first cuspule posterior to the large cusp so distinctly set off from this 

 primary cusp. The cuspules of the talonid are more nearly in the 

 median line of the tooth than was observed in Z>. haydenianus. The 

 tooth is distinctly larger than in D. niicrolestes from the Crazy 

 Mountain locality in the Fort Union of Montana. 



An isolated fourth upper premolar may possibly belong to Didy- 

 mictis but is too small to belong to the form represented by the 

 lower tooth. Moreover, the deuterocone portion does not extend 

 forward so markedly as in the Torrejon material of Didymictis^ a 

 condition suggestive of Ictidopa'p'pus., but the posterior cusp, though 

 prominent, is not developed into so nearly a shearing blade as in 

 either Didymictis or Ictidopafpus. 



A fragment of the trigonid portion of a lower molar collected 

 during the 1939 season may represent Didymictis, but it adds little 

 or nothing to our information regarding the form occurring in the 

 Dragon. 



CONDYLARTHRA 



Genus DRACOCLAENUS " Gazin 



DRACOCLAENUS GRIPHUS " Gazin 



Dracoclaeniis griphus Gazin, 1939b, p. 2S1. 



The material in the Dragon collection representing Di^acoclae/nus 

 griphus most closely resembles that of the Torrejon form Protoselene 

 opisthacus but differs from it in several respects. A relatively large 

 number of specimens, though fragmentary, are referred to this form 

 and four of these are figured (fig. 14) . 



P* (fig. 14, d) in specimen No. 15705 is larger and more inflated 

 than in P. opisthacus, although there is much variation in P* of 

 material referred to P. ojnsthacus, such as between Amer. Mus. Nat. 

 Hist. Nos. 16614 and 3285. In size of P* D. griphus approaches 

 Mioclaenus turgidus, but with less reduction of the cingulum and no 



10 SpaKWJ' i\T^'^,on-\-claenus- 

 " Oriphua, an enigma. 



