Microtus mordax halli [Ellerman], Fam. and Genera of Living Rodents, British Mus. Nat. Hist., 2:603, March 21, 1941 (new name for Microtus mordax angustus [Hall]).
Type.—Obtained at Godman Springs, 5,700 ft., Blue Mountains, Columbia County, Washington, by S. H. Lyman, on September 1, 1927; type in Museum of Vertebrate Zoölogy.
Racial characters.—Size small; color of sides pale grayish brown; brown dorsal stripe conspicuous; tail relatively short.
Measurements.—Four males and 5 females from eastern Washington average, respectively: total length 164.8, 166.6; length of tail 55.8, 55.8; hind foot 22.0, 21.4.
Distribution.—From the Blue Mountains of southeastern Washington north, along the eastern edge of the state, to British Columbia, and thence west, north of the Columbia River, to the Cascades, and south along the eastern edge of the Cascades to the Wenatchee Mountains. Marginal occurrences are: Pasayten River ([Taylor] and [Shaw], 1929: 24), Hart Lake ([Taylor] and [Shaw], 1929: 24), Blewett Pass (W.W.D.), Boulder Cave (W.W.D.), and Satus Pass (W.W.D.).
Remarks.—Four specimens from Satus Pass, Klickitat County, are somewhat intermediate between this race and macrurus, and indicate that halli crossed the Columbia River when an alpine meadow land extended from the Simcoe Anticline to southeastern Washington.
One specimen from Selah, Yakima County, is colored somewhat like halli, and is smaller than macrurus. Possibly the halli type of meadow mouse spread northward to the Yakima Valley. This specimen was taken in the Upper Sonoran Life-zone. A specimen from the Arid Transition Zone at Naches, Yakima County (taken in almost Canadian Life-zone habitat), is like macrurus-halli intergrades from the higher Cascade Mountains.
Microtus longicaudus macrurus [Merriam]
Microtus macrurus [Merriam], Proc. Acad. Nat. Sci. Philadelphia, p. 353, October 4, 1898.