1894.] NATURAL SCIENCES OF PHILADELPHIA. 153 



Above, iucludiug tail, top of head, upper arm and liind thighs to 

 middle of feet, light liver-brown of nearly the same shade as seen in 

 fall specimens of ermhiea from Pennsylvania. Below, including in- 

 side of hind legs, distal half of hind feet, posterior two-thirds of 

 forelegs, and all of forefeet, pale yellowish white. Muzzle, below 

 margins of upper lips, an irregular patch above, but not reaching 

 nose, an irregular streak half-way between nose and eyes and reach- 

 ing behind anterior corner of eye, an ascending streak broadly 

 rising on cheek and narrowing forward to just over eyes and not con- 

 necting with nose patch, also a short median streak between ears, pure 

 white. A sparse patch of long bristling white hairs guards the open- 

 ing of the ear. Two-thirds of the tail colored like the back, distal 

 third, black. Tail two-fifths of length of body, very slender, sparsely 

 haired, the terminal pencil short. 



/S/;?f^/. — (Post-palatal and post- frontal regions missing) intermediate 

 in general configuration between frenattis and xanthogenys ; in size 

 very near the latter. Mandibles very massive and short ; dentition 

 also massive and crowded. The sudden post-orbital expansion of an- 

 terior portion of brain- case indicates that part to be relatively larger 

 and more inflated than in any other of our weasels, resembling most in 

 this cliaracter, erminea. Inner lobe of last upper molar slightly nar- 

 rower transversely than outer lobe, the tooth standing at an oblique 

 angle to the longitudinal diameter of the skull ; in all the allied forms 

 these proportions are reversed and the last molar is at right angles to 

 this diameter. In xmdhogemp the inner lobe is often twice the dia- 

 meter of the outer lobe. In 2)erdns-ul(e the longest diameter of the 

 first upper molar is at an angle of 45 with that of the second molar 

 and at rigid angle>< with that ot the premolar ; in the other species 

 the first and second molar diameters are generally in the same line, 

 never departing from it more than 15° and this diameter of the pre- 

 molar is never deflected from that of first molar more than 20° in 

 frenatns and erminea, nor more than 45° in xanthogenys. 



While the skull of penin.ndce is one-third smaller than that of fre- 

 natus of same age, the upper first and second molars are as large as 

 those of largest frenatus and absolutely stouter. Upper and lower 

 canines short and stout, the lower so massive basally as to crowd the 

 incisors into a double row, the second incisor of each mandible being 

 forced back of the other four, which form a solid anterior row 

 unbroken by the usual crowding forward of the second incisor be- 



