1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 459 
been to draw separately each of the principal displaced portions of the skull 
in their true perspective with relation to the median plane and combine 
them so as to correct the overlap and displacement. This has been very 
conscientiously and skilfully executed by the artist, Mrs. L. M. Sterling, 
under my supervision, aided by criticism from Doctor Gregory and Mr. 
Granger, the Tarsius skull being used for guidance and comparison. I take 
pleasure in calling attention to the accuracy and excellence of Mrs. Sterling’s 
work as instanced not only in the present difficult reconstruction but in the 
entire series of illustrations of Lower Eocene mammals treated in this 
revision, most of the specimens being fragmentary, many of them of minute 
size and some in poor preservation. 
The skull of Tetontus will be described by Doctor Gregory; in the present 
revision I confine myself to a discussion of the tooth characters. These 
have already been considered by Cope, Osborn and Wortman, but the pres- 
ent interpretation differs from theirs in certain important particulars, 
especially as to the front teeth, which are so widely different from those of 
Anaptomorphus that the genus must be regarded as distinct. 
Tetonius homunculus (Cope 1882). 
Anaptomorphus homunculus Corr, 1882, Pal. Bull. No. 34 (Feb’y. 22), Proc. 
Amer. Phil. Soc., Vol. XX, p. 152; 1885, Tert. Vert., p. 249, pl. xxive, fig. 1; OsBorn, 
1892, Bull. Amer. Mus. Nat. Hist., Vol. IV, p. 108, fig. 6; 1902, zbed., Vol. XVI, 
p. 2090, figs. 24, 25; Huprecut, A. A. W. 1897, Descent of the Primates (Princeton 
Lecture), p. 18, figure; Worrman, 1904, Amer. Journ. Sci., Vol. XVII, p. 248. 
Type, No. 4194, Cope Coll., a skull from the Wasatch of the Bighorn basin, 
Wyoming. | 
Specific characters: Lower molars mi; = mm. Teeth wider and more massive, 
jaw deeper than in the following species. 
Besides the type skull, No. 41 upper and lower jaws, No. 15063 upper and lower 
jaws, No. 15062 upper jaw, and Nos. 42, 43, 15064, 15065 and 15693 lower jaws, are 
referred to this species. 
Observations upon the type skull. The premaxillary region is broken off, 
the fractured surface apparently coinciding at several points with the 
maxillo-premaxillary suture. The fracture has, however, lost some of its 
freshness owing to repeated handling of the specimen during the thirty-five 
years since its discovery, and the sutural surfaces cannot be recognized with 
absolute certainty. The maxillary teeth were interpreted by Cope and 
Osborn as canine, two premolars and three molars. Wortman states that 
there is evidence of seven teeth, the most anterior represented by an alveolus. 
But it does not appear to me that the small concavity on the fractured 
anterior face of the right upper jaw which he interprets as a portion of a 
