Douglass : Vertebrate Fossils from Fort Union Beds. 17 



as figured in Cope's Tertiary Vertebrata, PI. LXII, Fig. 23. The 

 trigonid is high and has three small tubercles arising from the summit, 

 the median being minute. The anterior face of the trigonid is trans- 

 versely convex, the posterior face flat. The heel has a small, long, 

 sharp-pointed posterior cusp and two short lateral lobes which are 

 hardly well enough developed to be termed cusps. The heel is sep- 

 arated from the trigonid by a transverse valley. 



Family EPANORTHID^? Ameghino. 



Picrodus silberlingi gen. et sp. nov. 



(Plate I, figures 9-10.) 



(Type No. 1670, Carnegie Museum Catalogue ofVertebrate Fossils. ) 



The type consists of a portion of a mandible with two teeth. 



Size small ; mandible short and deep ; the last premolar a simple, 

 minute cusp with a small heel ; molar a long, low tooth with the long, 

 sharp cutting edge curved downward and outivard in the middle. The 

 first molar is about three tifnes the length of the last premolar. 



The teeth and jaw of this animal are peculiar. In certain of the 

 characters of its dentition it suggests some of the Epanorthidae which 

 Ameghino has discovered in Patagonia. Though only two teeth are 

 preserved, portions of seven alveoli can be seen in the mandible. 

 Three of these are anterior to P4 and are undoubtedly the alveoli of 

 the first three premolars. Behind My are four alveoli for two two- 

 rooted molars. Apparently the premolars were all simple, conical, 

 one-rooted teeth. The length of the anterior molar was greater than 

 the combined lengths of the last two molars. The depth of the 

 mandible under the first molar is about the same as the length of P4 

 and Mj. From Silberling quarry east of Bear Butte, Montana. 



mm. 



Length of portion of mandible preserved 10. 



Length of P^ 1.2 



Length of My ^.t, 



Order INSECTIVORA ? 

 Coriphagus montanus gen. et sp. nov. 

 (Plate II, figures 3-4.) 

 (Type No. 1669, Carnegie Museum Catalogue of Vertebrate Fossils.) 

 The type is the left portion of a mandible lacking the anterior part, 

 the angle, and the upper portion of the ascending ramus, with the 

 molars and the last three premolars in place. 



