1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 463 
Tetonius musculus sp. nov. 
Type, No. 12830, lower jaw with ms; and roots or alveoli of the preceding teeth, 
from the Lysite horizon in the Wind River basin, Wyoming. 
Specific characters: Lower jaw much more slender than in T. homunculus or 
ambiguus, canine root less compressed, premolars and molars less robust, ms less 
reduced, heel longer. 7 
This species has a much less specialized dentition than the two preceding 
but comes from a later horizon. Its reference to the genus is open to ques- 
tion. Itis about the size of Omomys minutus (Loomis) and is from the same 
ee, ay 
Fig. 33. Fig. 34. 
Fig. 33. Tetonius musculus, lower jaw, outer view, and crown view of last molar. Type 
specimen, Lysite beds, Wind River basin, Wyoming. 
Fig. 34. ?Tetonius musculus, lower jaw fragment, with ps—mz, outer and crown views. 
Gray Bull beds, Bighorn basin, Wyoming. 
locality and horizon, but is readily distinguished by the deeper jaw, shorter 
premolars, m3 with paraconid internal and connate with metaconid. 
No. 15066, lower jaw fragment with ps-me compares with this species, 
but if identical it can hardly be regarded as congenerie with 7’. homunculus. 
Absarokius gen. nov. 
Type, Anaptomorphus abbotti Loomis, 1906. 
Generic characters: Dentition 1.1.3.3. Molars similar to Tetonius; premolars 
of similar type but more specialized. Two lower front teeth in advance of p2, sub- 
equal and of moderate size, presumably incisor and canine. Fourth upper premolars 
oval, triangular, moderately wide, with small deuterocone; lower premolars crowded, 
much enlarged, with quadrate bases, deuteroconids absent, ‘more turgid than in 
Uintanius and without anterior cusp or blade. Upper molars ovate-trigonal, wide 
transversely, protocones set far in from margin, m* much smaller than m?, wide 
transversely, suboval. Lower molars wide with low cusps, the outer cusps set far 
in from margin, paraconid distinct on m,, internal and connate with metacone on 
mo_3. Last lower molar considerably reduced, hypoconulid small, narrow, entoconid — 
indistinct. 
