140 



BULLETIN 16 9, UNITED STATES NATIONAL. MUSEUM 



process is less internal, stouter, and more proximal; the ectepicondyle- 

 is more produced; the entepicondylar foramen, or rather canal, is 

 longer; and other differences of proportion and detail are seen. Never- 

 theless a relationship seems probable. The Ardorydes humerus was 

 supposed by Matthew to belong to a chrysoclilorid, but Schlaikjer 

 has shown that the e^^dence is all against this view and favors talpid 

 affinities. Ardorydes may belong with the dentitions and skulls 

 known as Proscalops. 



Figure 29. — Humerus of an unidentified fossorial mammal: a, Anteroexternal face; 6, posterointernal face-. 



Four times natural size. 



On the basis of the teeth, no genus known from the Gidley Quarry 

 w^ould seem to be closely allied to Proscalops. Some nyctitheriids 

 have been supposed to be talpids or at least talpoids, but the only 

 probable nyctitheriid in this fauna, Stilpnodon simplicidens, is too 

 small to have had this humerus. The humerus does not belong to a 

 multituberculate nor to any other order known in this fauna save the 

 Insectivora. It is not leptictid and cannot belong to Aphronorus if 

 that genus is really a pantolestid, but might if the genus does not 

 belong with Palaeosinopa and Pantolestes. It might belong to Gela- 

 stops but probably does not if that genus is correctly considered an:' 

 ally of Didelphodus. Eudaemonema shows some, but only very 

 distant, resemblance to such dentitions as Proscalops and might 

 conceivably have had a fossorial humerus. The dentition of the' 

 animal represented by this humerus may be unknown, although this 

 is improbable in view of the many jaws and few humeri collected 

 from the quarry. 



In any event the presence of such a specialized fossorial animal in 

 this ancient fauna is of great interest. 



