210 BULLETIN NO. VII. 
Onychomys leucogaster var. pallidus, var. n. 
O. leucogaster var. pallidus HERRIcK. Thirteenth Ann. Rep. Geol. Nat. 
Hist. Surv. Minn., 1884. 
This variety is based upon a series collected near the sources 
of the Minnesota river and the Bois des Sioux river in Dakota, 
which differs so completely in coloration from either of the 
above varieties as to be entirely incompatible with any descrip- 
tion as yet given of O. leucogaster, while at the same time pre- 
serving the essential characters of the species. 
Upon first encountering the form while encamped on the 
shores of Lake Traverse, the writer was at a loss to classify 
his find, for, in coloration and form, it entirely differed from 
any description or figure known to him. It was at once set 
down as an Arvicola on the strength of its compact, obtuse 
form and burrowing habit, although the large ears and a cer- 
tain vague suggestion in the appearance hinted at Hesperomys. 
It was necessary to examine the teeth before conviction was 
reached that we had to do with a Hesperomoid type. The mole- 
like appearance and habit at last furnished memory with the 
clue and we recognized our capture as Onychomys. 
It will be most satisfactory to transcribe the description made 
in our diary from the recently killed specimen, as being quite 
unprejudiced by thought of comparison with other species. 
Description of No. 103, collected July 4, 1885: ‘Color no- 
where other than black and white or a mixture of the two. 
Base of fur everywhere ashy gray; above, black and white 
most intimately mixed so as to produce the effect of a whitish 
reflection from black fur, thus resembling a mole. On the 
sides the white tips are more numerous among the hairs, so 
that the color is lighter, but the fur is so fine that the pelage 
would not be called grizzled. Under parts very pure delicate 
white (soft looking) but sparsely sown with black-tipped hairs. 
Soles hairy. Tail not distinctly bi-color.” 
There is a dark ring about the eyes, the white of the lower 
parts embraces the lips to the nostrils, and the muzzle is hoary. 
The lip is cleft and the fur about this cleft is long and hangs 
over like a moustache. The fur is close and dense about the 
small nasal pads. The insides and rims of the ears are silvery 
white. The tail is terete and very closely hairy, except at the 
tip, which isas naked as in Geomys, and is gradually reduced 
