Vol. 5] 



Merriam 



. — John Day Carnivora. 



35 



am inclined to accept the suggestion of Wortman 28 that a mem- 

 ber of the White River genus Daphaenus, like D. dodgei, may 

 lead to some of the short-jawed dogs of the John Day. The evi- 

 dence of relationship to this form seems at least as strong in the 

 case of Philotrox as in any of the other genera. D. dodgei has a 

 rather short, heavy jaw. Excepting P 1 , which is much reduced, 

 the premolars are heavy, and possess posterior cusps. The heel 

 of M x is broad and basin-shaped, the form and arrangement of 

 its three tubercles appearing to be much the same as in Ph ilotrox. 



So great is the diversity of form among the four genera of 

 short-faced John Day dogs that it is difficult to determine from 

 the material available whether we are warranted in considering 

 them all as descendants of the same stock. If such similarities 

 as they show are actually an expression of common ancestry, it 

 would seem that we find at least as many of the necessary charac- 

 ters of this ancestral type in the North American Daphaenus, as 

 in Cephalogale or in any of the European genera. 



The relationships of the previously known short-faced John 

 Day dogs to the European Simocyonines seem in a general way 

 to be far from close. The affinity with Cephalogale is presum- 

 ably not as close as with Daphaenus. Compared with Simocyon, 

 we find the dentition differing in each genus about as widely as 

 it could be made to differ and still keep them short-faced, heavy- 

 toothed canids. No single functional cheek tooth of Simocyon 

 shows much resemblance to the corresponding tooth of Oligo- 

 bnnis. This would be true also of the inferior cheek teeth and 

 upper carnassial of Enhydrocyon. The upper molars of Enfiy- 

 drocyon are too imperfectly known for comparison. In Hyae- 

 tweyon the inferior check teeth are different, as far as known. 

 The superior sectorial suggests a structure somewhat similar to 

 that of Simocyon, but M 1 is much smaller and there was no 

 second superior tubercular. 



It is to be expected that differentiation will tend to produce 

 short-faced, heavy-toothed carnivores of the hyaenoid type as 

 often and in as many places as circumstances will permit. The 

 Hyaenidae represent an Old World adaptation in this direction. 

 They have come to differ so far from the other groups of the 



* s J. L. Wortman. Am. Jour. Science, June, 1901, Vol. XI, p. 449. 



