30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



versely) of the upper molars but is appreciably smaller, being more 

 nearly comparable in size to Pelycodus ralstoni. The length of the 

 upper molar series in this specimen is 10.8 mm., whereas in N. limosiis, 

 U.S.N.M. No. 19293, the comparable measurement is 12.8 mm. 

 Moreover, both the hypocone and mesostyle in the Princeton speci- 

 men may be just a little less developed. The precise horizon for this 

 specimen is not known ; possibly it came from low in the section. 



A maxilla and jaw fragment found by Henry W. Roehler about 

 416 feet below the Tipton tongue on the southeast flank of the Rock 

 Springs uplift may well represent A'', limosus. While P* in the 

 maxilla is a little larger than this tooth in the figured specimen 

 (1952, pi. I, fig. 6) of A^. limosus, the molars correspond rather 

 closely. Moreover, M2 in the jaw fragment has a length comparable 

 to that in specimens of AT. limosus, which is less than in N. nunienus, 

 but its relative width seems unusual for either form. 



NOTHARCTUS, cf. NUNIENUS (Cope) 

 Various lower jaws and isolated teeth of Notharctus found in the 

 New Fork beds are consistently larger than any of the specimens 

 representing Notharctus limosus in the La Barge fauna. These may 

 well represent the Lost Cabin species A^. nunienus. The size of the 

 teeth compares very favorably with Cope's species. 



NOTHARCTUS, cf. VENTICOLUS Osborn 



The material representing the larger species of Notharctus, N., cf. 

 venticolus, in the La Barge fauna has been increased by about six 

 lower jaw portions and two maxillae. Only one or possibly two jaw 

 fragments with single teeth appears to be of the same species in the 

 New Fork fauna. However, a lower jaw (U.S.N.M. No. 22254) 

 with Ml and M2 and two isolated molars from the Cathedral Blufifs 

 tongue near Flat Top Mountain on the east side of the Washakie 

 Basin seem almost identical to certain of the La Barge specimens of 

 this form. No. 22254 is only slightly larger than the type of N. 

 venticolus. The specimen (P.U. No. 16109) cited by Morris (1954, 

 p. 197) as Notharctus, sp., from the Cathedral Bluffs, was cataloged 

 in the Princeton collections as Notharctus venticolus. It exhibits an 

 M2 that can also be closely matched in the La Barge material of 

 Notharctus, cf. venticolus, although it is a little smaller than in No. 

 22254 from these beds. 



NOTHARCTUS, sp. 



A lower jaw (U.S.N.M. No. 22255) with P3-M2 from beds be- 

 lieved to be a part of the Cathedral Bluffs tongue, on the northwest 



