234 MONOGRAPHS OF NORTH AMERICAN BODENTIA. 



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 1 and § as long as the hinder, as usual; on to|>, furred moderately, 

 the longer terminal hairs reaching the ends oi the claws bul not concealing 

 them; under the fingers, naked and annulate; on the palm, naked, with the 

 following tuberculatum: 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 liases 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- 

 nary Arvicola, but showing nothing of the dense furriness, like a rabbit's, of 

 Myodex or Cuniculus. There are six plantar tubercles, as usual in Arvicolince, 

 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 seen 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 liind 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 light fore foot of No. 8503 shows a curious abnormality; the third digit being arrested in 

 development, so that it is uo longer thau the til'lh. The left fore foot is normal. 



