142 Bulletin American Museum of Natural History. [Vol. XII, 



mastoid is prominent, and the paroccipital process has a more or 

 less backward direction. The foramina of the base of the skull 

 cannot be determined, but it appears probable that there was 

 a distinct post-glenoid present. 



The dentition, the formula of which is I. f, C. y, Pm. f, M. f, 

 has been quite fully described and requires but a brief mention. 

 It appears from the very perfect lower jaws that there were three 

 incisors present upon each side, although this is not entirely 

 demonstrable. In the upper jaw, the outer incisors are much 

 larger than the two inner pairs, which are subequal. The canines 

 are long and pointed, being slightly compressed at the base. The 

 first premolar is small, single-rooted, and has a simple crown. 

 The second is two-rooted and has a prominent posterior heel. 

 The third is three-rooted with two external and one internal 

 cusp. The fourth premolar, while possessing all the elements of 



Fig. 2. Oxycena lupina Cope. Upper and lower teeth, Y^ natural size. No. 107. 



the superior sectorial of the typical Carnivora does not form 

 a very perfect shear between the rudimental blade and that of the 

 inferior first molar. The great shearing function was transferred 

 to the first molar above and the second molar below ; the first 

 superior molar is curiously modified, in that the two original 

 external cusps are placed very close together, and a large post- 

 ero-external cusp added, which, in conjunction with the true 

 postero-external cusp, form a very effective blade, the internal 

 cusp being small. This is, at least, the interpretation which has 



