UTAH: _Boxelder Co._: _south fork of George Creek, 5 mi. SE Yost, Raft River Mts., 6700 ft._, 1 (UU); _George Creek, 7 mi. SE Yost, Raft River Mts., 6500 ft._, 6 (UU); _Pine Canyon, 6600 ft., 17 mi. NW Kelton, Raft River Mts._, 8 (MVZ); Pine Creek, 3 mi. N Rosette, Raft River Mts., 6100 ft., 2 (UU). _Marginal records._--Idaho: Camp Tendoy, Pocatello. Utah: Pine Creek, 3 mi. N Rosette, Raft River Mts., 6100 ft. Idaho: Mt. Harrison, 10 mi. S Albion. =Zapus princeps curtatus= Hall _Zapus princeps curtatus_ Hall, Univ. California Publ. Zool., 37:7, April 10, 1931. _Zapus princeps oregonus_, Taylor, Univ. California Publ. Zool., 7:281, June 24, 1911. _Type._--Female, adult, skin and skull, No. 7991, Mus. Vert. Zool.; head of Big Creek, 8000 feet altitude, Pine Forest Mountains, Humboldt County, Nevada; obtained on June 30, 1909, by Walter P. Taylor and C. H. Richardson, original No. 777 of W. P. T. _Range._--Pine Forest Mt's, Humboldt County, Nevada. See fig. 46. Zonal range: Transition and Canadian. _Description._--Size medium; back pale near Light Ochraceous-Buff with admixture of black hair forming dark dorsal band; sides lighter than back; lateral line faintly indicated; ventral surface white; tail bicolored, grayish-white to yellowish-white below and pale brown above; ears dark, edged with yellowish-white; feet grayish-white above; palatal bridge short; tooth-rows almost parallel; mastoid region of skull relatively narrow; incisive foramina wide posteriorly; narrow across zygomata; nasals relatively narrow posteriorly. _Comparisons._--For comparison with _Zapus princeps oregonus_ see account of that subspecies. _Remarks._--This jumping mouse, which was described from the Pine Forest Mountains, closely resembles _Zapus princeps oregonus_ but differs in lighter color, slightly smaller body, less divergent tooth-rows, shorter palate, and narrower skull across the mastoid region. The Pine Forest Mountains are isolated from neighboring boreal regions by a belt of the Upper Sonoran Life-zone, which is inhospitable to _Zapus_; therefore, intergrades between _Z. p. oregonus_ and _Z. p. curtatus_ are not known and probably do not exist. Nevertheless, _Z. p. curtatus_ shows close affinity with _Z. p. oregonus_, as indicated by Taylor (1911:281), and I agree with Hall (1931:7) that the relationships of _Z. p. curtatus_ are best expressed by arranging it as a subspecies of _Zapus princeps_. _Specimens examined._--Total, 18, all from Nevada, distributed as follows: _Humboldt County_: Pine Forest Mts.; Alder Creek, 6000 ft., 2 (MVZ); head of Big Creek, 8000 ft., 14 (MVZ); _Leonard Creek, 6500 ft._, 2 (MVZ); Meadow, 1 (MVZ). _Marginal records._--Nevada: Pine Forest Mts., Alder Creek; Meadow. =Zapus princeps idahoensis= Davis _Zapus princeps idahoensis_ Davis, Jour. Mamm., 15:221, August 10, 1931.