FAMILY MURID.E. 87 



scales beneath. Soles willi five tubeixles. Hind legs 1 -2 in length ; the internal toe shortest, 

 and the middle toe slightly longer than the adjacent one on each side ; near their bases, the 

 nails are slightly tinged with brown : all the toes have transverse scales on the under side. 

 Soles with five distinct tubercles, and another minute one opposite the internal toe. Tail 

 moderate, cylindrical, enlarged at the root, scaly, with rather sparse supine hairs, some of 

 which extend slightly beyond the vertebras. The whole body covered with an exceedingly 

 long and fine fur, standing half an inch high along the back, and slightly less on other parts 

 of the body. On the legs the hairs are short, adpressed beneath, and extend beyond the nails. 



Teeth. These correspond very well with the dentition assigned by Fred. Cuvier to the 

 Campagnols, (Dents des Mammiferes, p. 155,) with the following variations : The second 

 molar of the upper jaw is composed of five triangles, the posterior space being the largest, 

 elongated and sinuous. In the lower jaw, the incisors arc not as much rounded on their ante- 

 rior surfaces, are more slender, and twice the length of those above. In the first molar are 

 three internal triangles, of which the posterior is- largest ; in the second are an anterior, an 

 external, two internal, and a posterior transverse space ; the last molar has three irregular 

 spaces, the posterior being the largest, transverse and almost semilunate. All are so closely 

 united, that a casual observer would be led to suppose that there were many more teeth than 

 actually exist. In the broad and dilated processes of the lower jaw, almost concealing the 

 teeth, and in the position and shape of the triangular spaces on the crowns of the teeth, we 

 have a representation in miniature of similar parts in the Fiber zihethicus already described. 



Color. Above brownish grey, slightly darker on the back, approaching nearly in color to 

 the Browai Rat. This color passes into slaty grey on the chin, cheeks and abdomen ; the 

 base of the fur, on every part of the body, dark plumbeous. Feet dark brown above, cine- 

 reous beneath. Nose flesh-colored. Tail brownish above, lighter beneath, with a few hairs 

 fulvous at their base. 



Length of head and body, 5'0. 



Ditto of tail, 1-9. 



In another specimen the dimensions were, 



Length of head and body, 3 "9. 



Ditto of tail (vertebrae), 1"4. 



Ditto ditto (including fur), 1 • 6. 



This species affords another example of the great difficulty of determining whether it has 

 been previously described. A distinguished American naturalist is disposed to refer it to the 

 xanthognathus of Leach, (Zool. Miscell. Vol. 1. pi. 26.) It wants, however, the fulyous 

 cheeks, and the ears well covered with hair, attributed to that species by Richardson. Upon 

 the suggestion that it might possibly be the pensylvanicus of Ord and Harlan, it was shown 

 to both those gentlemen, who pronounced it to be totally distinct. We are inclined to believe 

 it to be the Meadow-mouse of Pennant, as cited above. His account, concise as it is, agrees 



