446 WoHman — Studies of Eocene Mammalia in the 



as mentioned above. There is a single specimen in the collec- 

 tion, which I refer to this species, and which, although a little 

 smaller than the type, agrees with it so perfectly in other 

 respects as to leave little doubt of the identity of the two. It 

 consists of the anterior part of the right mandibular ramus, figure 

 12, carrying the canine and the alveoli for the incisors and first 

 premolar, together with the posterior part of the jaw contain- 

 ing the first and second molars. Fortunately the first superior 

 molars of both sides are present. The alveoli indicate the 

 existence of three incisors, the second of which was pushed 

 well back out of the transverse line, as in the Canidse in 

 general. The canine is of moderate size, oval in cross-section, 

 and surrounded by a faint cingulum at its base. The first pre- 

 molar is not preserved, but the alveolus shows that it was 

 small, single-rooted, and placed a short distance behind the 



12 



Figure 12. — Right ramus of Uintacyon edax Leidy ; outside view. 

 Figure 13. — First and second lower molars of same specimen ; inside view. 

 Figure 14. — First lower molar of same ; crown view. 

 Figure 15. — First left upper molar of same ; crown view. 

 All the figures are three halves natural size. 



canine. The second and third premolars are missing; the 

 fourth displays the usual pointed crown without an anterior 

 basal cusp, but a strong posterior accessory cusp is developed. 

 As compared with the corresponding tooth of Vulpavus 

 llargeri, the accessory cusp of this tooth is much stronger, but 

 the heel is less prominent. It does not appear that the pre- 

 molars were reduced in size, at least abnormally so, since those 

 of the type are of the proportions usually seen in the Canidse. 

 The sectorial, figures 12-14, has a relatively smaller anteropos- 

 terior diameter than that of Vulpavus, the trigon having very 

 much the same shape and disposition of its parts. The principal 

 shear is very oblique and there is a well-developed posterior shear. 

 In the structure of the heel, however, the two genera are very 



