334 NORTH AMERICAN MUSTELID^. 



appearance of being greatly worn, asjis not, however, the case. 

 In fact, there is less difference with age here than elsewhere in 

 the family. The back upper molar is the largest tooth of all, 

 being as wide as, and much longerjthan, the sectorial tooth. It 

 is irregularly oval in shape, its long axis oblique; its face is 

 studded with obtuse tubercles in a manner scarcely admitting 

 of detailed|description. The back upper premolar is squarish, 

 with rounded-off angles, and presents outwardly a pair of large 

 obtuse tubercles, whereof the anterior one is the larger, sepa- 

 rated by a groove from an interior lower portion of the tooth 

 occupied by a single large, blunt, conical tubercle. The next 

 premolar is a blunt cone with a heel behind. The anterior pre- 

 molar is entirely similar, but much smaller, and crowded inward 

 from the general axis of dentition. It has but one fang; the 

 tooth behind it is two-rooted ; the sectorial tooth roots by three 

 fangs, two external, one internal; the upper molar is set in 

 three irregular shallow sockets. The back lower molar is trans- 

 versely elliptical rather than circular; its face is smooth and 

 flattened,^with a crosswise central depression. The anterior 

 lower molar is completely and bluntly tuberculous, showing only 

 traces of its likeness to the same tooth elsewhere in the family 

 in a slightly elevated, tri-tuberculous, anterior part, and a fiat- 

 tish, depressed hind part. The back lower premolar is an irreg- 

 ular, low, blunt cone, with a secondary eminence part way up 

 its inner aspect. The other premolars are successively smaller 

 and simpler. The front premolar and back molar are single- 

 rooted ; the anterior molar has four roots ; the next tooth three ; 

 the next two. The canines, both above and below, are rather 

 small, comparatively; the latter is not much curved. Of the 

 superior incisors, the lateral pair are moderately larger than the 

 rest, and taper somewhat toward the end from an elbow near 

 the base. The others are smaller, especially narrow, and some- 

 what club-shaped; none are obviously lobate. Of the inferior 

 incisors, it is seen to be the median pair that are missing, for 

 the next pair (here the middle pair) have the backward set, which 

 usually distinguishes them in other genera. These incisors are 

 all strongly clubbed at their extremities, which are irregularly 

 nicked. 



History of the species. 



The history of this species may be considered to have begun 

 iQ the middle of the last century. One of the earliest ac- 



