COISTDYLARTHEA. 435 



From the Big Horn region, Wyoming. J. L. Wortman. 



the metatarsals have the same length. These may belong to the P. nunienns. 



Phenacodus prim^vus Cope. 



Paleontological Bulletin No. 17, p. 3, October 25, 1873. Annual Report U. S. Geological Survey Terri- 

 tories, 1673, p. 458 (1874). Report on the Vertebrate Fossils of New Mexico. U. S. Geogr. Geol. 

 Surveys W. of 100th Mer., Capt. 6. M. Wheeler, 1874, p. 10. Report U. S. G. 6. Surv., W. of 

 100th Mer., G. M. Wheeler, iv, pt. ii, p. 174. 



• Plates LVIIb, LVIIc, LVIId, LVIIe, LVIIh, LVIII; fig. 11. 



The remains of this representative species are locally distributed, and 

 it is only recently that they have been obtained in any abundance. The 

 first one was dug by myself from a bank of the Wasatch Eocene marl on 

 Bear Eiver, Wyoming, in association with Corypliodon latipes and Hyraco- 

 theriiim index. The next specimens were obtained in only moderate abun- 

 dance from the Wasatch deposit of Northwestern New Mexico. It is in the 

 Big Horn Basin, Northern Wyoming, that the bones have been found abun- 

 dantl}' by Mr. Wortman, who also probably obtained it in the Wind River 

 region. Among the Big Horn specimens are several parts of skeletons, and 

 one almost entire one. This last specimen is the basis of the following 

 description, and with it the others will be compared. A restoration of the 

 species can be made from it. From the measurements, it is evident that 

 the animal was intermediate in size between a sheep and a tapir. 



Cranium. — The skull is rather elongate, with the anterior border of the 

 orbit a little anterior to the middle of its length. The preraaxillary region 

 is tapering, and the occipital region is not wide, but the interorbital space 

 is wide and flat. The sagittal crest, though elevated, is short, commencing 

 a little anterior to a line connecting the anterior borders of the glenoid cav- 

 ities. The zygomatic arches are rather straight, and are but little expanded 

 posteriorly. The lateral occipital crests are well marked. The anterior 

 prolongation of the skull is confined to the jaws, the facial surface being 

 short through the anterior abbreviation of the nasal bones. 



The premaxillaries are produced and narrowed anteriorly, and their 

 inferior and interior surfaces are flat and are connected by a convex exte- 

 rosuperior surface. Above the space between the third incisor and the 

 canine teeth, the superior surface is excavated so as to be longitudinally con- 



