28 



University of California Publications. 



[Geology 



With the support of excellent evidence, the opinion has been gen- 

 erally expressed that Temnocyon is in the line of descent from 

 Daphaenus. Hatcher has described as the ancestor of Temno- 

 cyon, a new genus, Protemnocyon, based on a new species, P. in- 

 fat us, from the Oreodon beds. Unfortunately Protemnocyon 

 was compared only with Cope's Temnocyon coryphaeus, which 

 is quite distinct from the typical Temnocyon, and is generally 

 recognized as a separate genus, Mesocyon. In some respects, viz., 

 enlarged brain case, lower sagittal crest, and reduced M 3 , Pro- 

 temnocyon represents a more advanced type than Daphaenus, 

 and in the character of the molars it approaches Mesocyon some- 

 what more closely than does the true Daphaenus. The type an- 

 cestral to the true Temnocyon is approximated more nearly in 

 Daphaenus vctus, as previously suggested by several writers. 



