94 Annals of the Carnegie Museum. 



of the diastema. A portion of the last deciduous molar is in position 

 and My and Mo- are fully erupted, but they have received very little 

 wear. M-^ is still buried in the jaw. In two specimens, C. M. Nos. 

 3195 and 3454, referred to this species, P4 is in position. In No. 

 3195 Pj is just appearing through the alveolar border, while that of 

 No. 3454 is well worn (See PI. XXXVII, Figs. 12-13). When P^ 

 in these two specimens are compared with those of similar ages in 

 Leptomeryx, the similarity is surprisingly close. Thus the antero- 

 internal tubercle on P^f of a young or unworn tooth of Leptotragiilus 

 is as well marked as, though rounder than, in Leptomeryx, and the 

 two ridges, which extend posteriorly from the protoconid, are quite as 

 well developed as in the Oligocene specimen No. 226 used for com- 

 parison. It is further to be noticed that of the two ridges just de- 

 scribed on P:f, the one which is external connects better with the heel 

 of the tooth than the one which is internal. This condition is similar 

 to that of the posterior premolars of Leptomeryx evansi noted by 

 Dr. Matthew.5* 



The lower molars are quite similar to those in Leptomeryx, the cross- 

 valleys being relatively somewhat wider, the heel of M^^^ more com- 

 pressed transversely, and the internal tubercle considerably smaller 

 (See PI. XXXVII, Fig. 12). 



M- and M- of No. 3009 arc not well preserved, but in a second young 

 specimen. No. 2919, somewhat advanced in age, M- and "M- are 

 perfect (See PI. XXXVII, Fig. 5). These teeth are more completely 

 selenodont than in any known Uinta artiodactyl. The st\les on the 

 external face are not strongly developed, though quite plain, while on 

 the internal face there are prominent cingula. There are no anterior 

 intermediate tubercles; in fact the upper molars quite closely suggest 

 such Oligocene forms as Leptomeryx, Ilypertragulus, and JLteromeryXy 

 as will be seen in the following paragraphs. 



27. Leptotragulus medius sp. nov. (Plate XXX\TI, Figs. 1-4). 



Type: Fragmentary skull and portion of mandible with M^j present; 

 fragments of femur; distal end of calcaneum and astragalus, C. M. 

 No. 2986. 



Paratype: Upper teeth and fragment of mandible with M;;. C. M. 

 No. 3453- 



Llorizon: Uinta Eocene; Horizon C. 



^'^ Bull. Amcr. Mus. Nat. Hist., Vol. XIX, 1903, p. 223. 



