54 Annals of the Carnegie Museum. 



first lower premolar is indicated by a single root separated from the 

 canine by a short diastema, but is continuous with the series back 

 of it. Pa^ has two roots closely crowded together. P3- is rather cur- 

 iously oxyaenid in structure, the main cusp consisting of a low conical 

 tubercle with a prominent conical heel and the anterior and internal 

 faces surrounded by a smoothly rounded cingulum; externally the 

 tooth is practically smooth. As already stated, the anterior face of Pj 

 is not present in the type; in the paratype, however, this tooth is 

 present, though isolated (see PI. XXXV, Figs. 12-13). The oxyaenid 

 feature of this tooth is again repeated, the main cusp being compara- 

 tively of rather small size, while the heel is large and of a trenchant 

 character. The anterior basal tubercle, though small, is well defined, 

 but there is no posterior accessory cusp, in this respect suggesting 

 such forms as Prodaphccnus (?) rohiistus, p. 50, or " Miacis'' vulpinus 

 Scott. 1^ The heel is, however, proportionally larger than in the two 

 species mentioned. There is a poorly developed cingulum on the 

 internal angle of the heel, otherwise the tooth is smooth. Mj has a 

 low trigonid with the external tubercle the largest, the internal of 

 moderate size, and the anterior small and low, this again agreeing 

 in a general way with Scott's description of " Miacis'' vulpinus. 

 The heel of My in the present species, though trenchant as in " Miacis" 

 vulpinus, is of large size, with an extended inner ledge, while that 

 of Scott's species is low and small. In comparing My of the present 

 genus with the miacids generally, it is apparent that Vulpavus pro- 

 fectus with its low trigonids bears a closer similarity to it than any of 

 the other genera. The basin-shaped heel of Vulpavus is, however, 

 totally unlike the large trenchant heel of the genus under consider- 

 ation, which in this respect is perhaps most suggestive of Oodectes her- 

 pestoides Wortman. In the present genus M^- is very little smaller 

 than Mj and the two are similar in every respect, except a somewhat 

 smaller sized anterior tubercle of the trigonid on M^- There are no 

 cingula on either of the two teeth just described. Mg is considerably 

 smaller than the preceding molars and is implanted by two fangs. 



The only portion of the skull preserved, besides the fragments of the 

 teeth described, is a mutilated fragment of the right maxillary, with 

 a portion of the zygomatic arch of the jugal attached. This fragment 

 may or may not pertain to the paratype here described. The alveolar 



^^"Amphicyon" (?) vulpinum, sp. n. Scott and Osborn, Proc. Amer. Phil. Soc, 

 XXIV. 1887, p. 255. 



