G. I. Adams — Extinct Felidce of North America. 431 



Dinictis br achy ops (Pogonodon br achy ops Cope). 



As will be further pointed out in this paper, Pogonodon must 

 be considered as a synonym of Dinictis. The tooth structure is 

 identical and the dentition differs only in the absence of the 

 second inferior molar, the reduction of which is indicated in 

 other species of Dinictis. The figure given in the series is from 

 the fragments of the skull described by Cope. The posterior 

 portion of the skull is reversed and the restoration of the outline 

 is conjectural. The skeleton is in part known and is very Dinictis- 

 like. This species is from the John Day. 



Dinictis platycopis (Pogonodon platycopis Cope). 



This is the largest of the series and with it is probably reached 

 the culmination of the Dinictis type as regards size. The profile 

 of the skull was probably more convex than is indicated in the 

 figure, which is taken from Cope's Tertiary Vertebrates, since the 

 specimen is slightly crushed. It is comparable with IT. occiden- 

 tal although exceeding it in size. The skeleton is not known. 

 The type specimen is from the John Day. 



Length of skull, condyles to premaxillary border, 235 mra 



The foregoing series of Dinictis species, of which the skulls 

 are figured in Plate XII, although less perfectly known than the 

 Hoplophoneus series, is comparable with it. The genus Dinictis 

 stands ancestral to the genus Hoplophoneus and, from what we 

 know, seems to have been more conservative. In both there is 

 a striking gradation in size. Iloplophoneus is greatly diversi- 

 fied in the White River. Dinictis remains are not so abundant 

 and three of the six species are known only from the John 

 Day, while only one species of Roplophoneus is known from 

 that formation. The range of the species in so far as I can 

 report them is expressed in the following table. 





White River. 



John Day. 





Titanotherium 



Oreodon 



Protoceras 







Beds. 



Beds. 



Beds. 





Dinictis fortis 



X 



X 

 X 

 X 



X 





" felina 





" sqaalidens -. 





" brachyops 



". platycopis _ 



X 

 X 



" cyclops 



X 



Hoplophoneus primsevus 



" oreodontis 





X 

 X 







" robustus 





X 







" insolens 





X 



X 





occidentalis 





X 







" cerebralis 









X 



