68 BULLETIN OF THE 



The internal anterior lobe of the superior incisor [sectorial] is very large, and 

 its apex is distinct from the inner side of the rest of the tooth. It is relatively 

 larger than in Crocuta brunnea. . . . The first true molar is somewhat wider 

 near the inner extremity of the crown than at the external extremity." (Bul- 

 letin U. S. Geological and Geographical Survey of the Territories, Vol. VI. 

 p. 388.) 



The Cambridge collection contains a mandible which should almost certainly 

 be referred to this species. It is proportionately short, stout, and of nearly 

 uniform depth, not tapering anteriorly as in JE. scevus; the symphysis is very 

 obliquely placed and the chin abruptly rounded, giving the jaw a somewhat 

 cat-like appearance. The first and second premolars are small, and the latter 

 is implanted by a fang which is but imperfectly divided into two ; the third 

 and fourth premolars are low but strong, and differ from the corresponding 

 teeth of the other species in the presence of a small anterior basal cusp. The 

 sectorial is large, and has a well developed metaconid ; the talon is obliquely 

 worn upon its outer side, showing a different mode of opposition of the teeth 

 from that which obtains in JE. scevus. The incisors are very closely crowded 

 together, and the median one is pushed very far back out of the line of the 

 other two. 



Measurements. 



m. m. 



Length, inferior molar series .032 Blade of sectorial (ant. post.) .013 



« " premolar series .031 Talon " " .006 



" sectorial (m. 1) .019 



? JSlurodon ursinus, Cope. 



(Syn. Canis ursinus, Cope.) 



Some large specimens agree best with the figures and descriptions of the 

 Canis ursinus, but they are so damaged as to render any final reference of them 

 impossible. Indeed, it is by no means clear that the species here named can 

 be regarded as distinct. 



-&' 



The systematic position of JElurotlon has been somewhat disputed. Leidy 

 placed it provisionally among the Felidce (op. cit., pp. 68 and 367). Cope, 

 though referring it to the Canidas, has regarded it as the forerunner of the 

 hysenas. " I nevertheless suspect that this genus is the ancestor of the Hyce- 

 nidce, through the intermediate forms Ictitherium and Hyamictis." (American 

 Naturalist, Vol. XVII. p. 244 ) Professor Cope has, however, informed us 

 that he does not attach much importance to this view. Schlosser has adopted 

 the same opinion, but believes that JE. scevus should be generically separated 

 from the other species. " Der Canis scevus, Leidy, wird von Cope zur Gattung 

 JElurodon gestellt, indess offenbar ohne hinreichenden Grand, denn sowohl der 

 Schadelbau, als auch die Beschaffenheit der einzelnen Zahne, namentlich des 

 oberen Pr. 1 sprechen sehr fur die Zugehorigkeit zu den echten Caniden, wah- 



