210 BULLETIN NO. VII. 



Onyehomys leucogaster var. pallidus, var. n. 



O. leucogaster var. pallidus HEKRICK. 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 is as naked as in Geomys, and is gradually reduced 



