1903.] Matthew, Fauna of Titanotherium Beds of Montana. 219 



in these beds. It is provisionally referred to Cope's species, 

 known hitherto by an upper and two lower teeth from Swift 

 Current Creek, Canada. These specimens will be described 

 by Professor Osborn in a later paper. 



HYRACODONTID^. 



Hyracodon sp. 



Two lower jaws and an upper molar belong to a species of 

 Hyracodon. I do not observe any important distinctions 

 from H. nehrascensis in the parts preserved; but in the ab- 

 sence of the diagnostic teeth (upper premolars) make no 

 specific reference. 



ARTIODACTYLA. 



■f^^44 



LEPTOCHCERID^. 



Stibarus montanus, spec, no v. 



No. 9668, a lower jaw containing the second, third, and 

 fourth premolars, and the first molar, enables 

 us to place the hitherto problematic genus 

 Stibarus in the Leptochoeridge. , , , , 



\L_Lf/ 



Generic distinctions. — Molars like those of Lepto- 

 chcerus. Premolars much like those of Leptomeryx, 

 but with lower and more rounded cusps. 



Specific distinction. — Third premolar with no 

 posterior cingular cusp. The second premolar is 

 long and laterally compressed, with three rovtnded 



cusps in line, the an- 

 terior the smallest, 

 the median the high- 

 est. The third premolar has a similar 

 form and composition, but the median 

 and posterior cusps are somewhat 

 larger, and there is a cingtilum around 

 the posterior end of the tooth. The 

 fourth premolar is wider but not much 

 over half as long as the third, it has a 

 main cusp, protoconid, an anterior 

 cusp connected by a ridge with it, a postero-intemal and postero- 

 external cusp, all worn off in the specimen and none marginal, and a 



Fig. 12. Stibarus 

 obtusilobus Cope, 

 type specimen, na- 

 tural size, from the 

 Oreodon Beds of 

 Northeastern Col- 

 orado. .-J, external, 

 A ', crown view. 



Fig. 13. Stibarus montanus, part of 

 lower jaw, type specimen, natural size. 

 A^ external, .,4*, crown view of teeth. 



