238 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. sa^ 



Genus DIDYMICTIS Cope 



DIDYMICTIS TENUIS," new species 



Type. — U.S.N.M. no. 9297, part of left lower jaw with broken P4 

 and complete Mi. Collected by Dr. J. W. Gidley. 



Horizon and locality. — Gidley Quarry, Fort Union, Middle Paleocene 

 horizon, Crazy Mountain Field, Mont. 



Diagnosis. — Much smaller than any comparable miacid. P4 with 

 short high main cusp and single posterior cusp, both subcorneal, 

 Ml with very elevated trigonid, hypoconid and entoconid about 

 equally high and distinct. Mi length 2.9 mm, width 1.8 mm. 



DIDYMICTIS MICROLESTES," new species 



7V2>e.— U.S.N.M. no. 9301, left lower jaw with P4-M2. Collected 

 by Dr. J. W. Gidley. 



Horizon and locality. — Gidley Quarry (and one referred specimen 

 from Silberling Quarry), Fort Union, Middle Paleocene horizon, 

 Crazy Mountain Field, Mont. 



Diagnosis. — Generally similar to D. haydenianus but much smaller, 

 anterior cusp of P4 higher and more trenchant, heel of P4 with one 

 central cuspule and one very small marginal posterior cuspule, posterior 

 end of P4 relatively wider and more transverse, talonid of M2 almost 

 as wide as trigonid. Measurements of type in millimeters as follows: 



Order CONDYLARTHRA 



Family PHENACODONTIDAE 



Most of Dr. Gidley's manuscript notes refer to this group, and he 

 evidently planned a preliminary paper on it. There are three separate 



*" Tenuis, feeblo. Oidley notes that two or three new species of this genus or family are present, but his 

 records contain no exact reference to these species. 

 « liucpit, sm&U+'KritTijt, plunderer. 



