ARTIODACTYLA. 721 



basal lobes separates it. The well-developed pair of anterior inner tuber- 

 cles shows that it cannot be an abnormal Hyopsodus vicariue, with which it 

 agrees in size. The first anterior inner tubercle of the true molars is more 

 widely separated from the second anterior than in any of the species of the 

 genus, and is quite as in the species of Pelycodus. It is smaller than the 

 second anterior inner, which equals in size the anterior outer. The heel is 

 wide, inclosing a basin, which is bounded externally by an angular ridge. 

 Its posterior inner angle supports a cusp, which is separated by a deep 

 notch from the anterior inner cusp. External to it, on the posterior border 

 of the crown, is a small tubercle. No basal cingula. 



Measurements. 



M. 

 Length of true molars 0. 010 



Diameters M. ii I ''°*"''P°^*"'°'" ^^ 



( transverse 003 



Depth of ramns at Pm. iv 007 



Basin of the Big Horn. J. L. Wortman. 



Pantolestes brachystomus Cope. 



Proceeds. Amer. Philos. Soc, 1883, p. 547. Mioelwnus brachystomus Cope, Paleontological Bulletin No. 



34, p. 187, February 20, 1882. 



Plate XXIII d, figs. 16-21. 



This small Artiodactyle is represented by the fragments of the skeleton 

 of but one individual. These include the greater parts of the maxillary 

 and mandibular bones, with the teeth; a lumbar vertebra; parts of both in- 

 nominate bones, and of both femora, with the right tarsus with the attached 

 portions of the tibia and metatarsus. The bones are about two-thirds the 

 size of those of the Javan musk-deer (Tragulus javanicus). The transverse 

 extent of the superior true molars is greater than the anteroposterior. The 

 composition of the last molar is like that of the others. The external 

 tubercles are lenticular in section, and the emargination which separates 

 them is apparent on the external face of the crown. The intermediate 

 tubercles are small, and are entirely distinct from the large external tuber- 

 cle. There is a distinct cingulum which is only wanting from the inner 

 base of the crown. The fourth superior premolar has a trilobate outline of 

 the base of the crown, the base of the inner lobe being contracted where it 



joins the external part of the crown. The internal tubercle is conic, with 

 46 c 



