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 ocanthogna- 

 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. 



ARV1COLA H1RSCTUS. 



PLATE XXV. FIG. 2. — (STATE COLLECTION.) 



Meadom-mmtsc. Pennant, Arct. Zool. Vol. 1, p. 133. 

 Arvicola hirsiitus. 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, largest 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 0'8 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 middle 

 ones subequal, the one nearest the thumb being somewhat longest : all the toes with transverse 



