Four specimens from 4 mi. NE El Rito, 7000 ft., New Mexico, show intergradation, in the shape of the nasals and incisive foramina, in the robustness of the zygomatic arch, and in the breadth of the braincase with a specimen of _Zapus princeps princeps_ from Tierra Amarilla, New Mexico. In color and in external measurements as well as in other cranial characters they closely agree with typical _Z. p. luteus_ and are here referred to the latter. _Specimens examined._--Total, 49, distributed as follows: ARIZONA: _Apache Co._: North Fork White River, White Mts., 24 (SDM); Alpine, 8500 ft., 6 (USBS); West Fork Black River, 7700 ft., 8 (MVZ); _Greenlee County_: Hannagan Creek, 8200 ft., 2 (MVZ). NEW MEXICO: _Otero Co._: 12 mi. E Cloudcroft, 7500 ft., 2 (USBS). _Rio Arriba Co._: 4 mi. NE of El Rito, 7000 ft., 4; Espanola, 5000 ft., 2 (USBS). _Socorro Co._: Socorro, 1 (USBS). _Marginal records._--New Mexico: 4 mi. N El Rito, 7000 ft.; Espanola, 5000 ft.; 12 mi. E Cloudcroft, 7500 ft. Arizona: Hannagan Creek, 8200 ft.; W. Fork Black River, 7700 ft.; N. Fork White River, White Mts. New Mexico: Socorro. =Zapus princeps minor= Preble _Zapus princeps minor_ Preble, N. Amer. Fauna, 15:23, August 8, 1899. _Zapus hudsonius campestris_, Bailey, N. Amer. Fauna, 49:117, January 8, 1927 (part). _Type._--Adult female, skin and skull, No. 73673, U. S. Nat. Mus. Biol. Surv. Coll., Wingard, near Carlton House, Saskatchewan; obtained on July 23, 1895, by J. Alden Loring, original No. 3123. _Range._--Most of southern half of Saskatchewan and Alberta, northeastern Montana southeastward to Aweme, Manitoba, and Webster, South Dakota. See fig. 46. Zonal range: Transition, Hudsonian, and Canadian. _Description._--Size, small; back dark, usually with a distinct mid-dorsal band of black mixed with Warm Buff; sides lighter, more yellowish, but always with an admixture of black hairs; lateral line distinct, near Ochraceous-Buff, ventral surface characteristically suffused with Ochraceous-Buff; tail bicolored, grayish-white to yellowish-white below and pale brown above; hind feet grayish-white above; ears dark, edged with white or yellowish-white; skull small; postpalatal notch often anterior to posterior part of molars; inferior ramus of zygomatic process of maxillary often with well developed medial projection; auditory bullae flattened; nasals narrower anteriorly and proximal third depressed; base of zygomatic process of squamosal broad. _Comparisons._--From _Zapus princeps princeps_, _Z. p. minor_ differs as follows: Size averaging smaller in all measurements taken, except least interorbital constriction which is approximately the same; color dorsally and laterally more yellowish, less Ochraceous-Buff; ventrally greater suffusion of Ochraceous-Buff. For comparison with _Zapus princeps idahoensis_ see account of that subspecies.