CARNIVORA. 



SINOPA, Leidy. 



A genus of small carnivorous animals, which Dr. Leidy 

 regards as intermediate between the recent Canis and the ex- 

 tinct Hycenodon. Owing to the fragmentary condition of the 

 remains found, no satisfactory generic definition has been 

 given. 



From the portion in our collection, we are able to throw 

 some further light upon the genus, summing up the generic 

 characteristics thus : Small carnivores, which have the last 

 upper premolar as sectorial (thus differing from Hycenodon}, 

 the other premolars simple and conical. 



The sectorial is shorter, antero-posteriorly, than the pre- 

 ceding tooth ; has a short blade of a single lobe, and a large 

 cusp developed from the posterior part ; a cingulum sur- 

 rounds the entire crown. The lower sectorial has the blade 

 of a single lobe, and with a short heel. 



SINOPA RAPAX, Leidy. 



Proceedings of Ac. Nat. Sc., 1871, p. 115. 



In addition to the molars of the lower jaw, described by 

 Dr. Leidy, we have what corresponds to the third and fourth 

 premolars of the fox, their dental formulas being probably the 

 same. 



The third premolar is small and pointed, differing from the 

 corresponding tooth in the fox, (i) in its being less com- 

 pressed, (2) in its shorter antero-posterior diameter, (3) in 

 thes traighter and more nearly equal margins, and in (4) the 

 absence of a posterior heel. 



The tooth is inserted by two fangs, as in Canis and Hyceno- 

 don. The posterior shows a rudiment of a third, which is 



