234 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
not noticeably if at all exceed those of the hind feet, and are of ordinary 
arvicoline shape. The fingers have the usual relative lengths;* thumb 
rudimentary, with abortive, flat, appressed nail; third digit longest, fourth 
scarcely shorter, second shorter, fifth much the shortest. The fore feet are 
between § and 3 as long as the hinder, as usual; on top, furred moderately, 
the longer terminal hairs reaching the ends of the claws but not concealing 
them; under the fingers, naked and annulate; on the palm, naked, with the 
following tuberculation: besides the pollical node, there is a tubercle just 
antero-external of this, another at base of the fifth and second toes respect- 
ively, and another at conjoined bases of third and fourth toes—five in all, count- 
ing the pollical protuberance. The hind feet, likewise, show nothing notice- 
ably different from Arvicola or Evotomys; speaking in general terms, the 
relative size is the same, and so are the proportionate lengths of the digits. 
The feet are hairy on top to the claws (the longest terminal hairs just 
reaching the ends of the claws), and the soles are moderately furry on the 
posterior third (as far as the back tubercle); perhaps a trifle pilose for ordi- 
uary Arvicola, but showing nothing of the dense furriness, like a rabbit’s, of 
Myodes or Cuniculus. There are six plantar tubercles, as usual in Arvicoline, 
thus disposed :—one posterior, of moderate size, conical, not lengthened, 
situate about half-way between heel and bases of middle toes; a smaller one 
close by, but a little further forward and more external; then one at base of 
inner toe—these three completing a triangle; one at base of second toe; one 
at base of fifth toe; one between bases of third and fourth toes. The toes, 
as usual, are strongly annulate beneath, with terminal smooth pad. The tail has 
“nearly the usual length, calibre, and hairiness of Arvicola, showing no approach 
to the brevity and rabbit-like furring of Myodes or Cuniculus. Its length varies 
in-our specimens. In Baird’s type, No. 1368, the only tail séen till now, this 
member is noticeably longer than the hind foot, and distinctly bicolor ; in our 
Oregon animal, No. 3798, it barely exceeds the hind foot, and is indistinctly 
bicolor; in the Kansas skins, it averages no longer than the hind foot, and is 
almost unicolor. 
In color, both as to its pattern and its shade, and in general superficial 
appearance, there is little to distinguish this animal from Arvicola riparius, 
for instance. Aside from the Oregon animal, which is in poor if not sickly 
condition, and taken in August, the pelage is beautifully fine, soft, and full, 
*The right fore foot of No. 8508 shows a curious abnormality; the third digit being arrested in 
development, so that it is uo longer than the fifth. The left fore foot is normal. 
