1896 1 Geology and Paleontology. 47 



2. Pms. !r 2 pm. 2 reduced or absent H. oreodontisWhhe River. 



3 - Pms - ! H. primaewis White River. 



B. Skull large, occiput overhanging. 



Superior sectorial with incipient anterior basal cusp. 



4. Pms. i! pm. 2 reduced or absent H. robtutus White River. 



5 - Pms - I H. insolens White River. 



6. Pms. I inferior sectorial with no posterointernal cusp, heel 

 reduced, H. occidentalis White River. 



Hoplophoneus occidentalis Leidy. 

 In The Extinct Fauna of Dakota and Nebraska (1869) Leidy de- 

 scribed two fragments of a mandible which he thought indicated a 

 species larger than Hoplophoneus primaewis and to which he gave the 

 name H. occidentalis (Drepanodon occidentalis), figuring the specimen 

 in Plate V. No further material was referred to this species until 

 1894, when Osborn and Wortman in describing a collection of White 

 River fossils in the Bulletin of the American Museum of Natural His- 

 tory determined two specimens as H. occidentalis, giving measurements 

 of the more important bones of the skeleton in comparison with those 

 of H. primaevus. While pursuing my studies in the American Museum 

 through the kindness of these gentlemen, I found that a complete man- 

 dible of specimen No. 1407 from the Oreodon Beds agrees in every 

 particular with Leidy 's type, which I have had the privilege of exam- 

 ining in the Philadelphia Academy. A drawing of the mandible 

 accompanied by a faithful copy of Leidy's figure is given in the accom- 

 panying plate. Associated with the mandible are several vertebrae 

 and portions of limb bones showing the skeleton to be much larger than 

 the specimen previously determined as H. occidentalis in the American 

 Museum Bulletin. They however, agree, as does also the mandible, 

 with Dinotomius atroz described by Dr. Williston in the Kansas Uni- 

 versity Quarterly, January, 1895, from a fine skull and nearly com- 

 plete skeleton. This specimen which I had the pleasure of seeing last 

 summer I now have no hesitation in referring to H. occidentalis. It 

 makes possible the determination of the skeletal characters and affini- 

 ties, and the restoration promised by Dr. Williston will complete our 

 knowledge of this species. The following measurements are taken from 

 the Kansas University Quarterly. 



Length from inion to premaxillary border . . . 260 mm. 



Width of zygomata 145 " 



Length of mandibular ramus 164 " 



