MAMMALS OP MINNESOTA. 91 



thus brought about in the weasel causes the great reduction of 

 the last molar and the apparent revolution of the axis through 

 90 degrees, so that it stands at right angles to the remainder of 

 the series. It is this condition of the orbits and zygoma and 

 the abbreviation of the facial region which finds its extreme in 

 the weasels which produces, in part at least, the great exten- 

 sion of the palate in that group ; and the converse condition 

 in Mephitis produces the effect of a deep emargination of the 

 palate extending frequently as far as the molars. In most of 

 the other Mustelidce the palatal bridge extends more than half 

 way to the pterygoids. 



The form of the teeth, as well as their position, differs from 

 that of the types of the family. The upper incisors are chisel- 

 shaped and bent backward near the end, while those of the 

 lower jaw are straight and squarely truncate apically, opposing 

 the surface thus formed to the oblique edge of the upper teeth. 

 The lower premolars are small and conical, while the third 

 upper one is the sectorial. It has, however, a very considerable 

 development of the salient anterior lobe found even in Putorius 

 but so highly developed in the badgers that the tooth is as 

 much a grinder as a sectorial. The upper molar is quadrate, 

 but wider than long. The lower jaw as a whole differs very 

 little from that of the Mustelince. The foramina incisiva are 

 narrow. The posterior nares are separated by a bony septum 

 almost to the posterior edge of the palate. The pterygoids 

 are hooked and of moderate size. The zygomatic arch is not 

 compressed laterally, nor as strongly curved upward as in 

 the Mustelince. The glenoid fossa is of considerable size and is 

 well arched behind, yet looks more downward than in the 

 weasels, although never locked. The auditory bulla lies close 

 to the post-glenoid prominence, and the meatus opens just 

 posterior to the zygomatic process of the temporal, in contrast to 

 that of the Mustelince. The bullae are very little inflated, in this 

 respect differing greatly from the badgers. The mastoid pro- 

 cesses are produced and directed forward. 



Generic characters of Mephitis. 



Teeth, 34 ; formulas : i. f :|. c, }:i, pm. |:|, m. fcf Frontal region 

 tumid, dorsal outline of skull irregular. Palate not extending 

 beyond the molar series. Condyle of mandible projecting later- 

 ally, coronoid process with both margins convex, angle slightly 

 flaring outward. Soles quite narrow. Tail very long and 

 bushy. Color black with white dorsal markings. 



It is now accepted that there are but two valid species of 



