70 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



PANTODONTA 



CORYPHODONTIDAE 



CORYPHODON RADIANS (Cope) 



(Plate II, figures 1-5; plate 12, figures i and 2) 



Coryphodon would appear to be most abundantly distributed in the 

 lower levels of the Knight. Remains are of common occurrence at 

 the Bitter Creek locality and at the base of the Knight section west 

 of Elk Mountain in the Fossil Basin. Much highly fragmentary 

 material was noted along the lower slopes of Fossil Butte although 

 the precise level represented here is not certain. Remains are much 

 less frequently encountered in the higher levels in the La Barge- 

 Big Piney area and none has been found in the New Fork and Ca- 

 thedral Bluffs beds. Extinction may well have coincided with the 

 changes that brought about the Tipton tongue of the Green River. 



Coryphodon radians is the first name that has been applied to 

 Coryphodon in North America; and since the type material is from 

 the Bear River locality near Evanston, there is no question of its 

 being represented in the Knight in at least one of the faunas for this 

 member. In all probability all the reported materials from the dif- 

 ferent horizons of the Knight are of this species. However, only one 

 of the skulls in our collection, U.S.N.M. No. 20737 (see pi. 11, fig. i) 

 from near La Barge shows the spur from the metacone described 

 by Osborn (1898, p. 213) as characterizing C. radians. I suspect, 

 however, that this is, as a vestigial feature, highly variable. I note 

 also that the spur extending posteroexternally from the protocone 

 to the posterior cingulum of this tooth must be regarded as variable, 

 because in a skull from Bitter Creek (U.S.N.M. No. 22745; pi. 11, 

 fig. 4) it is exhibited on the right side but not the left. 



Two skulls (U.S.N.M. Nos. 22745 and 22748; pi. 11, figs. 4, 5) and 

 an incomplete pair of lower jaws (U.S.N.M. No. 22746, pi. 12, fig. 2) 

 from Bitter Creek could with certainty be referred to Cope's Corypho- 

 don armahis. There is no doubt but that this is the place where he 

 obtained the remains of two poorly preserved skulls upon which the 

 species was based. C. armatus was the third North American species 

 to be named, and the second, C. semicinctus, was placed in synonymy 

 with C. radians by Cope himself. C. armatus was the type of Cope's 

 genus Metalophodon characterized by the unusual appearance of M^ 

 Earle (1892) regarded Metalophodon invalid because of variation in 

 the characters of M^. I believe, however, that the tooth in this position, 

 as figured by Cope in his Tertiary Vertebrata (1884, pi. 49, fig. i). 



