86 NEW-YORK FAUNA. 
Total length,. 5'0. 
Length of head and body,. 3'0. 
Length of tail,. 2'0. 
It is with hesitation that I venture to consider this animal as new. It will be found to differ 
from riparius by its larger and more arched head, and its dental structure ; from xanthogna- 
thus, to which it bears some resemblance, by its relative dimensions ; from noveboracensis of 
Richardson, by the blunt nose and rudimentary thumb ; and from borealis, by its nearly naked 
tail, and comparatively shorter fur. It only remains for us to consider it under a new name, 
at the hazard of swelling the already interminable list of synonimes. . 
We have little to add, except that it was first obtained from low grounds in the neighborhood 
of Oneida lake. I subsequently found it in great numbers in the forests of Hamilton and St. 
Lawrence counties. It was exceedingly active and lively, and frequently seen running along 
on fallen timber. When disturbed, it retreated to its burrow at the roots of trees. It may be 
added, that variations in the length of its tail frequently occur. In specimens of the dimen¬ 
sions given above, the tail varied from one and a half to two inches. 
THE BEAVER FIELD-MOUSE. 
Arvicola hirsutus. 
PLATE XXV. FIG. 2. —(STATE COLLECTION.) 
Meadow-mouse. Pennant, Arct. Zool. Vol. 1, p. 133. 
Arvicola hirsutus. Emmons, Mass. Report, 1840, p. 60. 
Characteristics. Dark brown above, deep ash beneath. Tail less than half the length of the 
body. Ears membranous, concealed. Length five to five and a half inches. 
Description. Body robust, compact, larges' across the fore shoulders, sensibly less over the 
loins. Head pyramidal. Whiskers numerous, scattering, radiated, black and white, some of 
them extending beyond the eyes. Nose flesh-colored cleft, and covered to its tip with short 
rigid hairs ; nostrils lateral. Eyes small and black, almost hidden in the fur, and about half an 
inch from the nose. Ears large, round, membranous, concealed beneath the fur, apparently 
naked behind, but in fact sparsely furnished with hairs which extend beyond the margins; 
within naked, except towards the edges ; auricular opening large, and presenting a tripartite 
cavity. Anterior to the ears, the fur is so long, and unites so well with that on the borders of 
the ears, that although they are in fact quite large, they are not obvious ; they are distant about 
an inch and a half from the extremity of the nose. Tongue smooth and fleshy, with a longi¬ 
tudinal furrow. There is a reduplication of the skin posterior to the upper incisors, which is 
furnished with hairs. Three transverse furrows anterior to the molars. Fore feet O' 8 long, 
with four toes, and a thumb furnished with a minute nail; the remaining toes have white 
compressed, pointed claws, deeply channelled beneath ; the external shortest, the two midc 
ones subequal, the one nearest the thumb being somewhat longest: all tire toes with transverse 
