I 30 Bulletin Atnerican Museum of Natural History. [Vol. XII, 



Size one third larger (lineal). Upper premolars compressed. 

 Type No. 6851 (referred to Amphicyon hartshornianus by Cope). 

 Both species are from the John Day. 



2. Dental formula ^ — . 



3-1-4-3 



a. Temnocyon Cope. Heels of lower molars trenchant, without internal ridge. 

 Trigon of m^ trenchant, without internal cusp. 



T. altigenis Cope. Nos. 6855 (type), 6856. 

 T. wallovianus Cope. No. 6858 (type). 

 T. ferox Eyerman. No. 6857. 



b. Hypotemnodon Eyerman. Heels of lower molars trenchant, internal ridge 

 vestigial or wanting. Trigon of m^ with prd and med of equal size. 



H. coryphcEus (Cope). Nos. 6859 (type), 6860, 6862, 6922, and doubtfully 

 Nos. 6861, 6920, 6909, etc. 



H.Josep hi {Co^e). Nos. 6878 (type), 6863, 6908, 6921. 

 All from the John Day. 



c. Cynodictis Brav. and Pom. Heels of lower molars basin-shaped. Upper 

 molars extended transversely. The American species are : 



C. gregarius (Cope). Nos. 5297 (type), 5298, 5299 (fig. sp.), 1004, 1383^ 

 1472, 8774, 5300. No. 6879 is probably a distinct species but does not pre- 

 sent any well-marked specific characters. 



C. lippiucottianus (Cope). Nos. 5327 (type), 8757-63, 1384, 1389, etc. 

 Teeth one fifth greater in lineal dimensions, somewhat more robust. Sectorial 

 proportionately larger, shear less transverse. 



? C. teinnodon, n. sp. Size of Hypotemnodon josephi ; lower premolars smaller 

 than in that species and trigon wider ; p- (in associated upper jaws) with internal 

 cusp almost obsolete, shear rather more longitudinal than in Cynodictis lippin- 

 cottianus, m^ well extended transversely. 



C. gregarius and C. lippincottiamis come from the Oreodon beds (except 

 the one skull No. 6879, of doubtful reference, which comes from the John Day). 

 C. teinnodon is from the Protoceras beds. 



d. Nothocyon (section Primasvi). Upper molars short transversely ; p^ 

 small ; lower molars with wide basin heels, trigon of m^ reduced, and a small 

 accessory cusp at its postero-external corner. 



N. latidens (Cope). Nos. 6896 (type), 6897-99. 

 A', lenuir (Cope). Nos. 6888 (type), 6889-94. 

 All from the John Day. 

 3. Premolars reduced. 



a. E7ihydrocyon Cope. Dentition 3-1-3-2. 



E. stenocephalus Cope. Nos. 6901 (type), 6902. 

 John Day. 



b. Hycenocyon Cope. Dentition 



3-i-3?-i 



H. basilattis (Cope). No. 6904 (type). 

 H. sectorius (Cope). No. 6905 (type). 

 John Day. 



