414 NOTES ON THE CANID.E OF THE WHITE RIVER OLJGOCENE. 



63. The known American species of the genus are : C. gregarius Cope and G. 

 lippincottianus Cope (the latter doubtful) from the White Rive]-, and C. gregarius Cope, 

 C. geismarianus Cojje, C. latidens Cope and C. lemur Cojie, from the John Day. 



64. The dogs are represented in the Uinta by two lines, ? Cynodictis and lliacis, the 

 former continued through the White River and John Day and the latter apparently 

 passing into Daphcenus of the White River, and through this into Temnocyon, Hypo- 

 temnodon, Cynodesmus and Enhydrocyon of the John Day, Oligobunis of this formation 

 being probably an immigrant from the Old World. 



65. M. Boule's hypothesis that the alopecoids are derived from Cynodictis and the 

 thooids from Amphicyon implies an improbable degree of convergent development, but 

 it is not to be rejected as impossible. According to present evidence the alopecoids 

 arose relativel}' late from the thooid stem. 



66. The thooid line appears to be Miacis — Daphcemis — Cynodesmus — Canis, the re- 

 tractile claws of Daphcenus having been clanged when the digitigrade gait and cursorial 

 habit were assumed. 



67. The very many resemblances between Daphcenus, Cynodictis and Dinictis were: 

 probably not independently acquired, but point to a common Eocene ancestor. 



68.. The early members of the canines, felines, mustelines and viverrines all have a 

 great many more structural features in common than do their existing representatives 

 and would seem to converge to a single Eocene type, which may prove to be the 

 creodont family Miacidce. The hyaenas and bears belong to a later cycle of develop- 

 ment and were derived, the former from the viverrines and the latter from the dogs. 



Literature. 



Adams, G. I. '96. The Extinct Felida> of North America. Amer. Jonr. Sci.. 4t1i Ser., Vol. I. 



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 Bruce, A. T. '83. Observations upon the Brain Casts of Tertiary Mammals. Boll. Princeton Geol. Museum, No. 3. 

 Cope, E. D. '84. Tertiary Vertebral a, Washington, 1884. 



Eyerman, J. '96. The Genus Teninocyon. etc. American Geologist, Vol. XVII. 

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