Douglass : Vertebrates from Montana Tertiary, 



169 



between Eporcodon and Proincrycochanis. It is a small species of 

 Promerycocha-rus, but larger than Eticrotaphus. 



Dentition. — I- and ^ are nearly equal in size, convex anteriorly 

 and flat posteriorly. They are of moderate size. The upper canine 

 is quite high, is flat behind with sharp edges. Near the tip it is tri- 

 angular with three sharp angles, but nearer the root it is convex anteri- 

 orly. There is a concavity running lengthwise of the tooth in front 



Fig. 12. ProinerycocJiccrus minor (No. 769). Upper Oligocene ? near Drum- 

 niond. Half natural size. 



of the inner angle, but no high narrow ridge as in Mesoreodon. 

 There is a short diastema between this tooth and Pi. The latter is 

 narrow and overlaps outwardly P^. Most of the teeth of the molar- 

 premolar series are narrower transversely than in Mesoreodon. The 

 anterior and median buttresses on M^ and ^ are narrow and not heavy. 

 \.j and J have nearly the same size and form, are chisel-shaped, con- 

 vex on the posterior face, but rather thin antero-posteriorly. I^ is 

 larger. The incisiform canine is still larger, triangular in section and 

 overlaps I^, the interior portion of its anterior face being behind the 

 outer portion of that tooth. There is no diastema between the canine 

 and caniniform Pl. This premolar is laterally compressed, lenticular 

 in section and sharp-pointed, having been made sharp by the wear on 



