236 VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 



supernumerary roots characteristic of the genus, and its length is equal to that of 

 the premolar series together with the diameter of the canine. The sectorial and 

 pm T of the second jaw have the characters seen in M. orthostichns. 



Measurements. 



mm. 



Length of dental series, including canine ; no. 1 ; 25 



" of premolar series ; 7 



" of sectorial; 10 



Depth, ramus at pm-^ ; 7 



" " at m T , posterior root ; 7 



u u u « u no 9 ; G 



Mephitis obtusatus Cope. 1 



This, the smallest species of the genus, is only known so far by a nearly entire 

 right mandibular ramus, which has the condyle, angle, and symphysis complete, and 

 all the molars excepting the pn% and the m-^. Canine alveolus complete. 



Besides its small size, this species may be recognized by the form of the ramus, 

 which is like that of M. leptops ; by its small sectorial tooth, and by the rudiment- 

 ary character of the angle of the mandible. The alveolus of the canine indicates a 

 tooth relatively as large as in the skunk. The third premolar has two roots, which, 

 like those of the second, are planted transversely in the jaw. The pm T has no 

 trace of posterior cutting lobe. The sectorial is a diminutive of that of M. orthos 

 tichus, having the same low metaconid and entoconid. The external median root 

 is present. 



The inferior border rises posteriorly but not so conspicuously as in M. orthos- 

 tichus and M. mephitica. The symphysis is steep and the ramus convex externally 

 posterior to the canine, as in M. leptops. The masseteric fossa is deeper and better 

 denned, especially inferiorly and posteriorly, than in most of the species. The 

 angle is represented by the thickening of the convex posterior border of the fossa, 

 which is recurved as far as the condyle, in a way not seen in M. mephitica, 

 M. fossidens, M. orthostichus, or M. putorins. The anterior border of the coro- 

 noid process, which has lost only the apex, slopes more obliquely posteriorly than 

 in either of the four species just named. 



It is only necessary to compare Mephitis obtusatus with M. leptops, which 

 approaches nearest in dimensions and has the same form of the anterior part of the 

 ramus, and nearly the same positions of the pmSj.g-. The length of the sectorial is 

 much less in M. obtusatus, equalling the premolar series only; in M. leptops its 

 length equals this plus the diameter of the canine. The dimensions of M. obtusatus 

 are materially less, and the positions of the pms^ 3- more absolutely transverse than 

 in M. leptops. 



1 None of the specimens labelled by Prof. Cope bear this name. 



