296 PROCEEDINGS OF THE ACADEMY OF [1892. 



Two species certainly belong to this genus, C. (Pelycodus) pelvi- 

 dens Cope and C. truncatus Cope, both from the Puerco. In addi- 

 tion we may provisionally refer to it three other species, of which 

 the upper dentition is unknown, but whose lower teeth agree closely 

 with those of the typical species ; these are : C. {Deltatherinm) 

 Baldwini Cope, and C. stenops Cope, from the Puerco, and C. {Pely- 

 codiis) angulatus Cope, from the Wasatch. 



PKOTOCHRIACUS, gen. nov. 

 Syn. Chriacus Cope, in part. 



This genus is closely allied to Chriacvs, but differs from it in a 

 number of details. P* has no distinct deuterocone; the upper 

 molars are less extended transversely, the hypocone is smaller and 

 the protostyle absent. In the lower molars the trigonid and talon 

 are of nearly equal height. Two species: P. (Chriacics) priscus 

 Cope, and P. {Chriacus) simplex Cope. Puerco. 



EPICHRIACTJS, gen. nov. 

 Syn. Chriacus Cope, in part. 



In this genus the upper molars resemble those of Chriacus but 

 the last lower premolar has all the elements of a molar, though 

 not fully developed. The trigonid rises considerably above the 

 talon. The third molar in both jaws is very much reduced. The 

 mandible is long and slender. The humerus has a thin, broad and 

 low trochlea with large epicondylar foramen and very prominent 

 supinator ridge. The ulna has a long olecranon and the sigmoid 

 notch is very oblique to the line of the shaft. The astragalus is very 

 peculiar; the trochlea has a remarkably limited antero-posterior 

 extent and is nearly flat transversely, but very oblique, high on the 

 external and very low on the mesial side, where there is a depression 

 for the internal malleolus of the tibia. The ectal calcaneal facet is 

 very large and widely separated from thesustentacular fiicet, which is 

 very narrow ; the neck is very slender and directed obliquely 

 distally and inward. 



One species: E. (Chriacus) schlosserianus Cope: Puerco. 



PENTACODON, gen. nov. 

 Syn. Chriacus Cope, in part. 



Upper teeth unknown. Anterior lower premolars very small 

 and simple in construction, p* is large, with large heel and very distinct 

 deuteroconid. The molars increase in size from the first to the 



