1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 9 
These teeth are very suggestive of Tricentes, but the molars are more 
rounded in outline, mg more reduced, and the size is greater. In many 
features they also suggest Clenodon and Palwarctonyx, but the cusps al- 
though low, are not flattened out as in those genera, the proportions of the 
Wa 16/62 
No 16/62 
3A . Pe : 
aie 
Fig. 5. 
Fig. 4. Thryptacodon antiquus, upper teeth outer and crown views of p*-m’ and outer 
view of upper canine, natural size. Type specimen, Gray Bull beds, Clark Fork Basin, 
Wyoming. 
Fig. 5. Thryptacodon antiquus, lower jaw, outer view, and crown view, “of lower pete: 
natural size. Type specimen, Gray Bull beds, Clark Fork Basin, Wyoming. 
Fig. 6. Thryptacodon antiquus, type specimen, distal end of humerus and proximal end 
of radius, natural size. Gray Bull beds, Clark Fork Basin, Wyoming. 
molars are different. But there is probably a near affinity between the 
less specialized Arctocyonide, the Cercoleptoid Miacide and the Oxycle- 
nidee, although part of the resemblance is due to parallelism. 
Thryptacodon olseni sp. nov. 
Type, No. 15252, askull and large part of the skeleton, found by Mr. George Olsen 
a few miles east of Saint Joe in the Gray Bull horizon of the Wasatch. 
The specimen is poorly preserved, and more or less encrusted with a 
flinty matrix. It consists, besides the skull, of eighteen vertebrae, most of 
the limb bones and an incomplete fore foot. A second specimen No. 16163, 
upper jaws with well preserved teeth, is referred to this species but has more 
rounded teeth, approaching P. antiquus in this respect. 
