ij02 THE JOHN DAY FAUNA. 



The teeth of this species are about half the size of those of A. vetus 

 Leidy. The entire animal was probably about the size of the kit fox, V^dpes 

 velox. 



The specimens above described were obtained by C. H. Sternberg and 

 J. L. Wortman, in the Bad Lands of the John Day epoch, in the John Day 

 Valley, Oregon. 



TEMNOCYON Cope. 



Paleontological Bulletin, No. 30, p. C, Dec. :!, 1878. Proceed. Amer. Phil. Soc, 1878, p. 68. Btilletiu 



U. S. Geol. Siirv. Terrs., vi, p. 179. 



Dental formula: I. =— ; C. - ; Pm. -; M. -. Two molars in each iaw 

 %'6 14 3 ^ 



tubercular. Inferior sectorial with well-developed heel, which is keeled 



with a cutting edge above. An internal tubercle of the same. A post- 



glenoid, but no postparietal foramen. Humerus with an epitrochlear 



arterial foramen. 



The characters on which I rely at present for the discrimination of this 

 genus from Canis are two. The first is the presence of a cutting edge on 

 the superior face of the heel of the inferior sectorial, in place of a double 

 row of tubercles surrounding a basin. When well develo^ied these char- 

 acters present a broad contrast, but indications of transitional forms are not 

 wanting. Thus, in some extinct Canes the internal crest of the heel is less 

 elevated than the external, which is the homologue of the single crest of 

 Temnocyon, and in some specimens of Temnocyon coryplioeus there is a cin- 

 gulum on the inner side of the median keel, which represents the internal 

 crest of Canis. Secondly, the epitrochlear foramen of the humerus, a char- 

 acter common to all of our Lower Miocene Canidce yet known. 



The keel of the sectorial, which defines this genus, is simply a repeti- 

 tion on that tooth of the heel which belongs to the posterior premolar teeth 

 of many Carnivora. It finds resemblances in such Eocene forms as Mesonyx 

 and PalcEOnyctis. Among recent Canidce it is apparently unknown, and is 

 very rare in other groups. The Cynodictis crassirostris Filhol, from the 

 French Phosphorites, stronglj^ resembles the species of Temnocyon in generic 

 characters. 



