318 



THE WASATCH FAUNA. 



toes opposed the internal three or the entire foot was directed outwards 

 from the Hne of the calcaneuni. In the hitter case the hallux may have 

 been opposable, as in the opossum, but in a much less degree. The tail 

 was long and stout. 



Species of this genus were abundant during the Wasatch epoch in New 

 Me.xico and Wyoming, and probably over the entire continent. Thev have 

 not yet been reported from higher Eocene beds, not even occurring in the 

 Wind River. A small species is found in the Puerco A species (0. r/aHice) 

 has been recently detected in the Eocene of France by M. H. Filhol. 



This genus resembles Fterodon, as described and figured by Gervais, 

 in the dentition of the maxillary bone; but the teeth of the lower jaw are 

 totally distinct in character, approaching more nearly those of the Palceo- 

 nyctis of De Blainville. According to Gervais, the inferior molars of 

 Pterodon are like those of Hycenodon, without interior tubercle, and the 

 inner lobes of the superior molars are not so large as in Oxycena. The latter 

 differs from Palceonycfis in the character of the antepenultimate lower fnolar, 

 which in Oxycena is characterized by the presence of a median blade, but 

 in Palceonycfis by a heel supporting (in the typical species) two tubercles. 



OXYJE^A FORCIPATA Cope. 



Report Vert. Fose. New Mexico, 1874. p. 12. Report Capt. G. M. Wheoler, U. S. G. G. Expl. Surv. W. 

 of 100th Mer., iv, ii, p. 105, 1877; pi. xxxv, xxxvi, xxxvii. 



Plate XXIV b, figs. 11-15; XXIV c, figs. 1-18. 



This formidable animal was abundant in Northern Wyoming during 

 the Wasatch epoch. At least ten individuals are represented in the collec- 

 tion from the Big Horn basin. The following are the dimensions of the 

 mandibles of the five best preserved. 



Length of dental series 



Length of premolar series 

 Depth of ramus at M. iii .. 



The measurement .035 for the length of the premolars given in my 

 report to Captain Wheeler, loc. cit, refers to the anterior three teeth, which 

 were originally supposed to be the only premolars. 



