RODENTIA— ARVICOLINAE—ARVICOLA GAPPERI. 
521 
The skull bears a very close resemblance to that of Arvicola rutila, so close, indeed, that with 
the limited materials at my command I am unable to indicate reliable characters to separate 
specimens from Massachusetts and Lapland. 
This species exhibits a very close resemblance in many respects to Arvicola rutila of Pallas, 
as shown by a comparison with specimens from Sweden and Kamtschatka. The size, general 
shape, peculiar pattern of coloration, and characteristics of skull are nearly the same. Both have 
the rufous back well defined against the lighter sides, the whitish feet and under parts. The ears, 
however, in A. rutila are smaller and more densely covered with short hairs. The hind feet 
are shorter, scarcely over .65 of an inch; the sole much more densely pilose from the heel, 
beyond the first tubercles, or for more than half'the length ; the hairs longer. The most con¬ 
spicuous distinctive feature, however, in addition to the shorter, more hairy soles, is the 
shorter tail. The vertebral portion of this is shorter than the head, and not more than half as 
long again as the hind foot; it is very thick and does not taper till very near the end. It is 
covered very densely with long, stiff appressed hairs, longer beneath and terminally than above 
and at the base, and with a rounded pencil at the tip projecting more than one-third the length 
of the vertebral portion. The American species, on the other hand, has the tail thinner, 
longer than the head, nearly twice as long as the hind foot; less densely coated with shorter 
hairs, which are not appreciably longer in the posterior than the anterior half; the terminal 
pencil in which is shorter. 
The species appears quite distinct from the Hypudacus glareola of Keyserling and Blasius. 
The Arvicola gapperi was first described by Gapper in an article on the mammals of the dis¬ 
trict of Canada between York and Lake Simcoe. He supposed it to be the A. noveboracensis of 
Rafmesque, but Dr. Richardson having pronounced it undescribed, the editors of the Zoological 
Journal called it after its discoverer. It has not hitherto been indicated as occurring within 
the limits of the United States, though apparently not rare in eastern Massachusetts. 
I am very much inclined to consider the Arvicola fulva of Audubon and Bachman as identical 
with this spec ; es. 
66 L 
Measured before skinning. 
