1894.] NATURAL SCIENCES OF PHILADELPHIA. 261 



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into the United States, at least to southern Idaho, western Washing- 

 ton, and Oregon. Xebrascensi.s represents that of the western Plains. 

 It is probable that artemisife is included in the list of " Hesjyeromys 

 lei(copi(y," given by Dr. Merriara in N. American Fauna, No. 5, 

 from Idaho, which he states may "eventually merit separation into 

 two or three subspecies." 



Artemisice was taken in the open, semi-arid foothills and lower 

 mountain slopes around Ashcroft, their burroAvs often being situated 

 on a bare hillside, a mile or more from other shelter than that afforded 

 by the scant growth of dwarf sage, which here nearly reaches its 

 northernmost limit of existence. 



Note ox Sitomys Americanos Arcticus. 



The series of White-foote<^l Mice taken at Nelson, in the Selkirk 

 Mountains, B. C. , and at Field, in the Rocky ^lountains, B. C. , at 

 elevations of from 3,000 to 5,000 feet, fit so well Dr. Mearns' diag- 

 nosis (vid. sup. cit.)of aS. a. arcticus from the Hudson Bay Territory, 

 I feel almost assured, without the type before me, that they are the 

 same. 



Those from Vernon, a locality intermediate in its faunal characters 

 between those of Ashcroft and Field, are intergrades between arte- 

 misice, with its short tail and light fulvous colors, and arcticus, with 

 longer tail and dark mouse-gray shades. It is reasonable to expect 

 that the vast boreal regions of interior N. America, bounded on the 

 east by Hudson Bay, on the west by the Cascade Mountains, and 

 south by the higher mountain ridges which invade the northern 

 border of the United States, is tenanted by no other race or species 

 of the S. amerlcauus type than arcticus. 



