TRANSACTIONS OF WAGNER 

 94 



UINTA SELENODONTS 



ences. The astragalus is somewhat narrower and has a rather more asym- 

 metrical proximal trochlea ; in the distal trochlea the cuboidal facet is even 

 narrower than in the White River types. The calcaneum has a much more 

 slender tuber, and the sustentaculum is more prominent, though very incon- 

 spicuous, which is a characteristic of the entire family. The cuboid is higher, 

 narrower, and more deeply incised by the calcaneal facet, while the astragalar 

 surface rises higher proximally. The navicular also has a greater proximo- 

 distal diameter. The meso- and ecto-cuneiforms are coossified, though their 

 limits are still clearly visible, and, as in the White River types, the former is a 

 little shorter than the latter. The whole tarsus is conspicuously higher and 

 narrower than in the subsequent genera of the family, in which the tendency 

 was continually to become short and broad, a tendency which reached its 

 maximum in Merycochcerns ; Prptoreodon departs much less in this respect 

 from the tylopodan stem as represented by Leptoreodon and Camelomeryx. 



The metatarsus is also elongate, as much so proportionately as in Lep- 

 toreodon. According to Marsh ('94, p. 267) at least a rudiment of the hallux 

 is retained, as I have also shown to be true of Ancodits. ('95^, p. 486.) The 

 other metatarsals closely resemble those of Oreodon except for their relatively 

 greater length, the median pair are enlarged, and the lateral pair (ii. and v.), 

 though longer, are almost as slender as in the White River genus. 



The phalanges are much as in the latter, but longer and more slender ; 

 those of the second row have the distal trochlea only slightly asymmetrical, 

 showing a less degree of convergence of the hoofs than in any recent artiodac- 

 tyls except the Tylopoda. The unguals are longer, narrower, more pointed, 

 and altogether more claw-like than in the later members of the group. 



MEASUREMENTS. 





P. 



parvus. 



P. parad. 



V. sp. 



Astragalus, length ..... 







0225 





O.026 



" breadth of proximal trochlea . 





.OI I 





.013 



Calcaneum, length ..... 







•039 



.048 



" dorso-plantar diameter of tuber, 







.OIO 



.013 



Cuboid, height ..... 









.013 



width 









.OIO 



Metatarsal ii., length .... 









.049 



" hi., " 









.060 



" iv., " .... 









.061 



v., 









.051 



