526 
U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
List of specimens. 
ARVICOLA RUFIDORSUM, Baird. 
Sp. ChJ —Size large. Above, bright rufous, or reddish chestnut; this tint paling very insensibly to the belly, where it 
changes rather abruptly to reddish white. No dorsal band. Feet reddish. Under surface of tail whitish. 
This species is of large size, nearly equal, indeed, to the A. ripairus. There are no very 
prominent peculiarities in form ; the ears being moderately large, well furred, and concealed by 
the hair of the head. The feet are large and broad; the soles with six tubercles; the posterior 
rather longer than usual. 
The upper parts and sides are a bright chestnut red, slightly obscured by dusky tips to the 
hairs, although these are only visible on close examination. The under parts of body and tail 
are white, tinged with dull yellowish ; the feet are reddish. 
This species, in its bright colors, resembles no other found in the eastern portion of the conti¬ 
nent, except, perhaps, A. pinetorum. This, however, belongs to a different section, with much 
shorter head, tail, and feet. From A. gapperi, the uniform red of the hack and sides will at 
once distinguish it. It comes much nearest to A. occidentalism but is larger ; has the red more 
vivid, and has no trace of the darker broad dorsal band. The tail, also, is shorter. 
The only specimen of this species I have ever seen was obtained at Holmes’ Hole, Massachu¬ 
setts, and belongs to the Boston Society of Natural History. 
List of specimens. 
Catalog’e 
number. 
Corresponding 
No. of skull. 
Locality. 
Whence and how 
obtained. 
Nature of 
specimen. 
Measurements. 
Tip of nose 
to tail. 
Tail to end 
of verteb. 
Tail to end 
of hairs. 
Hind foot, 
length of. 
Skull, length 
Skull, width] 
901 
1946 
Holmes’ Hole, Mass. 
Boston Soc. N. H. 
(borrowed..) 
Skin_ 
4. 20 
1.55 
1. 85 
.82 
# 
1.11 
.62 
