Vol. 5] Merriam. — John Dai) Carnivora. 59 



Philotrox x ...... 



Hyaenoc yon x 



Oligobvms x 



Proamphicyon x 



Amphicyon x 



Dinocyon x 



Ischyrocyon x 



Cynarctus x 



Of the nine generic types of eanids in the John Day fauna, 

 only one, Cynodictis, is considered identical with a White River 

 genus. The John Day form of Cynodictis has generally passed 

 under the same specific name as that of the White River beds, but 

 is distinguished from the latter by several characters. The brain 

 case is larger and the teeth are in some respects more specialized. 

 As a whole the type is more advanced than the White River 

 species. 



The genus Paradaphaenus, while not distantly removed from 

 Daphaenus of the White River in some characters, is in many 

 ways more advanced. The inner lobes of the upper molars are 

 broad, with well-developed hypocone. Intermediate tubercles are 

 also present on the crushing face. The brain case is relatively 

 much larger in the John Day form. 



The other John Day representatives of the Caninae are all 

 generic-ally quite distinct from any forms found in the White 

 River. As suggested by several writers, many of the John Day 

 genera represent advances along lines of specialization laid down 

 in the White River epoch. In Tcmnocyon, the cutting function 

 of the lower molars is a little more strongly expressed than the 

 decided tendency in this direction already shown in one form of 

 the White River Daphaenus. Mesocyon represents an advance 

 over the Daphaenus type in the better development of the shear 

 of the lower sectorial, and the partial reduction of the inner tu- 

 bercle of the heel. 



The three species referred to Nothocyon are closely related 

 if not generically identical with the John Day Cynodictis (?). 

 There can be hardly any question that the Nothocyons are a 

 modification of this stock in which the upper carnassials have 

 been shortened, the molars have approximated the quadrate 

 crushing type, and the brain case has become extraordinarily 



