896 THE WHITE KIVER FAUNA. 



extinct Mammalia of Dakota and Nebraska. It differs from all the speci- 

 mens of A. hartshornianus, in the disproportionately larger size of the tuber- 

 cular molars both above and below, and by the tendency of the heel of 

 the inferior sectorial to form a median keel. I found the fragments lying 

 close together without intermixture of other species, on an exposure of the 

 White River beds in Eastern Colorado, at the same locality which furnished 

 the specimens of A. hartshornianus. 



Amphicyon hartshornianus Cope. 



Bulletin U. S. Geol. Survey Terrs., vi, p. 178. 



Cania hartshornianus Cope, Synopsis of New Vertebrata of Colorado, Misc. pub. U. S. Geol. Surv. Terrs., 

 1873, p. 9. Annual Report U. S. Geol. Surv Terrs., 1873 (1874), p. 505. 



Plate LXVIIo; fig. 4. 



This was the most abundant species of the genus during the White 

 River epoch proper. It was originally established on a specimen from 

 Eastern Colorado, and I have subsequently obtained other specimens from 

 the same locality. On an examination of the specimens obtained by Dr. 

 Hayden in the Bad Lands of Dakota, now in the museum of the Philadel- 

 phia Academy, I find parts of four skulls, two of which have been figured 

 by Dr. Leidy on his Plate I, figs. 3, 4, and 6, and referred to in the text as 

 belonging to the A. vetus. I have also part of a skull with nearly complete 

 superior dentition from the John Day Valley of Oregon, which I cannot 

 distinguish from this species. 



The original specimen consists of a portion of the mandibular ramus 

 with the first tubercular molar and alveolus of the second. The species was 

 nearly as large as the Canis latrans. The anterior molar preserved has an 

 interrupted cingulum on the outer side, which projects considerably in front, 

 thus interrupting the parallelogrammic outline of the crown. The outer 

 anterior tubercle is much the larger, while the inner ones are both obsolete. 

 In Galecynus gregarius Cope the tubercles are equal, and there is no cingu- 

 lum. Root of tubercular molar subround in section, as in G. gregarius. 



Measuremenis. 



M. 



Length of bases of M. ii and iii 0130 



Length of base of crown of M. ii 0090 



Width of base of crown ofM. ii 0060 



Elevation of crown of M. ii 0050 



