1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. ie 
Sinopa mordax sp. nov. 
Type, No. 16157, lower jaws, from the Gray Bull horizon, Clark Fork Basin, 
Wyoming. 
Distinctive characters: M3 smaller than m, and slightly smaller than m2; py, with 
strong anterior basal cusp; canine stout with massive root; jaw thick and heavy 
especially at symphysis. M,_3; = 22 mm. 
Fig. 64. Sinopa mordax, lower jaw, type specimen, natural size, outer view and crown 
view of teeth. Gray Bull beds, Clark Fork Basin. 
The characters of this species show a marked approximation to the 
Oxyeenide, and especially to Prolimnocyon. It serves to emphasize further 
the near approximation of Oxyzenide and Hyznodontide in the lower stages 
of the Wasatch. 
Sinopa opisthotoma Matthew 1901. 
Sinopa opisthotoma Matruew 1901, Bull. A. M. N. H., Vol. XIV, p. 28, fig. 9. 
Type, A. M. No. 99, upper and lower jaws from the Wasatch of the Big Horn 
Basin, Wyoming, probably Gray Bull horizon. 
Distinctive characters: M,_3 = 31mm.; m? and m; relatively large with shear more 
antero-posterior than in other species. Lower premolars without anterior basal 
cusps; posteroexternal cusps of upper premolars weak or absent. The enamel of 
premolars and molars is rugulose with anastomosing vertical ridges. 
Pa. and me well separated on m! and m?, heels of mi_: broad basined; a small me 
on m}, heel of ms; narrow and elongate. 
Thirteen specimens from the Gray Bull Wasatch of the Big Horn Basin 
are referable to this species. It is about as large as S. hans, but of very 
distinct type. 
Sinopa shoshoniensis sp. nov. 
Type, No. 16158, a lower jaw from the Gray Bull beds of Clark Fork Basin, 
Wyoming. Paratype, No. 15745, lower jaws and fragments of upper jaws, from lower 
