18S7.] ^OJ [Scott and Osborn. 



The systematic position of this genus can liardly be decided from tlie 

 material now at command ; it may be a forerunner of Leptomeryx, the 

 only genus of the White River formation which at all resembles it ; it 

 may be an ancestral type of the Cervidce, or a member of the traguline 

 series. These questions must for the present be left open. 



Measurements. 



M. 



Length lower premolar series 021 



Last lower premolar, antero-posterior diameter 007 



" " " transverse " 003 



First lower molar, anteroposterior diameter 008 



" " " transverse " 005 



Length lower true molar series (second specimen) 026 



Third lower molar, antero-posterior diameter (second 



specimen) 012 



Professor Marsh has named three genera of Uinta ruminants, Eomeryx, 

 Oromeri/x and Parameryx*, with one of which Leptotragulus may be 

 identical. As, however, no definition of these names has as yet been 

 offered, they cannot be used. 



Perissodactyla. 

 Epihippus uiniensis Marsh. f — This genus differs from the Bridger 

 Pliolophiis in having the last two inferior premolars of the molar pattern. 



Epihippus grncilis Marsh. — Some beautifully preserved specimens of 

 this small species are in the collection and show interesting differences 

 from the Wasatch Ilyracotherimn. The characteristic equine cusps at the 

 inner angle of the Vs on the lower molars are more isolated and distinct ; 

 the limb bones are proportionately longer and more slender ; the carpus 

 is higher and narrower ; the magnum is more depressed and like that of 

 AncliUlie,rium in shape ; there are still four digits in the manus, but No. 

 V is very slender ; the ulna is still further reduced. Epihippus forms a 

 very interesting transition to the horses of the overlying White River 

 deposits. 



Hyrachyas obliquideiu, sp. nov.— Specimens of this genus are not at all 

 uncommon in the Uinta deposits, but the only ones which can as yet be 

 satisfactorily determined belong to a species different from any of the 

 known Eridgcr species. This species is characterized by the last upper 

 molar, which has become exceedingly oblique and very like the corre- 

 sponding tooth of Aceratherium ; the antero-extcrnal lobe is greatly 

 reduced in size, the external wall of the crown is nearly parallel to the 

 posterior transverse crest and prolonged but little beyond it, so that the 

 posterior valley is almost obsolete, being even less developed than in 



* Introd. and Succ. of Vert. Life in America, pp. 20, 30. 

 t Loc. cit., p. 24. 



