THE MAMMALIA OF THE UINTA FORMATION. 409 



astrugaliis, foi-mini^ a large external malleolus, and as in all aitiodaetyls rests ui)()n 

 the lil)ular laeet of the caleaneum. 



The hind foot is very eloseij' siniilai- to that of Oreodon, even more so than is 

 the foi-e foot. The astragalus is somewhat narrower in proportion to its height and 

 the ditTerence between the external and internal condyles in size is somewhat more 

 marked. The internal condyle passes directly into the navicular facet, though inter- 

 rupted by a slight prominence. The distal end is very unequally divided between 

 the navicular and cuboidal facets, the former being much the larger; the difference is 

 perhaps even more marked than in Oreodon. These two genera agree thus with 

 Ano])lot}ierium and the Suina and differ from most ruminants in which the two facets 

 are of more nearly equal extent. The calcaneal facets and those for the malleolai' 

 processes of the tibia and fibula resemble the corresponding parts in Oreodon, ex- 

 cept that the distal calcaneal surface is largei*. The caleaneum is much more slender 

 than in Oreodon and is especially less expanded at the distal end. The fibular facet 

 lises to a greater height and distally is more abruptly marked, and the interval 

 between this fixcet and the distal end is considerably greater than in Oreodon. The 

 sustentaculum projects further internally, though decidedly small, as in all oreodonts. 

 The cuboidal facet is more arched and concave from before backwards, and narrower 

 from side to side, while the distal astragalar surface is Hatter and larger. In fact, 

 the caleaneum diffei's from that of Oreodon moi-e than does any other tarsal bone. 



The cuboid is higher and narrower than in Oreodon and the asti-agalar and cal- 

 caneal facets more equal, though the latter is somewhat broader. In correspondence 

 with the greater length of this part of the caleaneum, the cuboid is much more deeply 

 incised by the calcaneal facet, and the anterior edge of the navicular surface rises 

 high above it. The distal surface of the cu1)oid displays the usual facets for the 

 fourth and fifth metatarsals ; the latter is lai'ger and the former is smaller than in 

 Oreodon and of somewhat different shape. Another difference from this genus con- 

 sists in the greater extension dI' the hook-like projection from th ■ rear of the cuboid. 

 In lact the differences are so striking as to raise the suspicion that the si)ecimen 

 described belonged to some other genus, as unfortunately it was not associated with 

 teeth. lint from its correspondence with the caleaneum it very probably should be 

 referred to I'rotoreodon, and its dilferei'ces from the cuboid of ruminants and pigs 

 are even more marked than from Oreodon. 



The navicular is likewise higher and nariower than that of ( hmdon. l)ut other- 

 wise resembles it very closely ; its proximal surface is somewhat more deeply con- 

 cave and its anterior edge rather more sinuous. Cope's statements (No. 4, p. 510) 

 with regard to the cuneiforms of Oreodon, are in some respects inacctn-ate, and 



