_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.

_Remarks._--This geographic race is notably stable and retains most of its diagnostic characters throughout nearly all parts of its range.

Intergradation occurs with _Zapus princeps idahoensis_ at various localities in Montana, as is described in more detail in the account of _idahoensis_. Crowe (1943:406) gives evidence of intergradation between _Zapus princeps idahoensis_ and _Z. p. minor_ in specimens from Entrance in western Alberta. Crowe (_loc. cit._) described these individuals as intermediate in color (lateral line present, under parts washed with buff, sides and dorsal stripe rich in ochraceous), and in cranial characters (smaller skulls, anteriorly narrower nasals, shorter more deflected rostrum, and higher cranium); but he considered them closer to _Z. p. minor_.

A skin without skull from Kananaskis Valley, Alberta, shows intergradation between _Z. p. idahoensis_ and _Z. p. minor_. This individual is like _Z. p. idahoensis_ in dorsal and lateral coloring, but is nearer _Z. p. minor_ in ventral coloring and in the presence of a distinct lateral line. External measurements provide basis for tentatively a.s.signing the skin to _Z. p. minor_.

_Specimens examined._--Total, 118, distributed as follows:

ALBERTA: 4 mi. N Marinville, 2; Blindman River, 1 (USBS); Camrose, 1 (ROM); Red Deer River, 1 (USBS); Didsbury, Little Red Deer River, 1 (ROM); Kananaskis Valley, 7000 ft., 1 (ROM); High River, 2 (ROM); Lodge Creek, 2 (NMC).

MANITOBA: Shoal Lake, 6 (NMC); Oak Lake, 4 (NMC); Aweme, 7 (6 ROM; 1 USBS).

MONTANA: _Chouteau County_: Eagle Creek, 25 mi. SE Big Sandy, 3 (UM).

_Hill Co._: Fort a.s.siniboine, 1 (USBS); _Bear Paw Mt's, 20 mi. SE Fort a.s.siniboine_, 4 (USBS); _head Eagle Creek, Bear Paw Mt's_, 7 (UM).

_Valley Co._: Glasgow, 1 (USBS).

NORTH DAKOTA: _Benson Co._: 4 mi. W Leeds, 1400 ft., 2; _2 mi. W Fort Totten, 1400 ft._, 13; Fort Totten, 4 (USBS). _Bottineau Co._: 4-8/10 mi. N Bottineau, 2100 ft., 2; _3-1/2 mi. N Bottineau, 1920 ft._, 2; _2-1/10 mi. N Bottineau, 1800 ft._, 3; _Bottineau_, 1 (USBS). _d.i.c.key Co._: Oakes, 3 (USBS). _Grand Forks Co._: Larimore, 3 (USBS). _Montrail Co._: 6 mi. N Lostwood, 2 (USBS). _Nelson Co._: Stump Lake, 1 (USBS).

_Richland Co._: _Lidgerwood_, 1 (USBS); 4 mi. S Blackner, (USBS).

_Rolette Co._: St. John, 1 (USBS). _Sargent County_: _7-1/5 mi. E and 1-1/5 mi. S Oakes, 1200 ft._, 6; _3 mi. W Cayuga, 1000 ft._, 2. _Walsh Co._: Grafton, 2. _Ward Co._: _Minot_, 3 (CMNH). _Williams Co._: Grinnell, 2 (USBS); Buford, 2 (USBS).

SASKATCHEWAN: Wingard, near Carlton House, 2 (USBS); Fort Carlton, 1 (MVZ); Indian Head, 2 (USBS); Cypress Hills, N Maple Creek, 18 (NMC); _Battle Creek_, 1 (NMC).

SOUTH DAKOTA: _Day Co._: Webster, 1 (Chic. AS).

_Marginal records._--Saskatchewan: Wingard, near Carlton House; Fort Carlton. Manitoba: Shoal Lake; Aweme. North Dakota: Larimore; 4 mi. S Blackner. South Dakota: Webster. North Dakota: Oakes; Grinnell. Montana: Eagle Creek, 25 mi. SE Big Sandy. Alberta: High River; Kananaskis Valley, 2000 ft.; Red Deer River; Blindman River; 4 mi. N Marinville.

=Zapus princeps oregonus= Preble

_Zapus princeps oregonus_ Preble, N. Amer. Fauna, 15:24, August 8, 1899.

_Zapus major_ Preble, N. Amer. Fauna, 15:24, August 8, 1899, type from Warner Mt's, Lake County, Oregon.

_Zapus princeps major_, Hall, Univ. California Publ. Zool., 37:10, April 10, 1931.

_Zapus nevadensis_ Preble, N. Amer. Fauna, 15:25, August 8, 1899, type from Ruby Mt's, Elko County, Nevada.

_Zapus princeps nevadensis_, Hall, Univ. California Publ. Zool., 37:10, April 10, 1931.

_Zapus princeps palatinus_ Hall, Univ. California Publ. Zool., 37:8, April 10, 1931, type from Wisconsin Creek, 7800 ft., Toyabe Mt's, Nye County, Nevada.

_Zapus princeps princeps_, Anthony, Bull. Amer. Mus. Nat. Hist., 33:17, March 17, 1913.

_Type._--Male, adult, skin and skull; No. 78156, U. S. Nat. Mus. Biol.

Surv. Coll.; Elgin, Blue Mountains, Union Co., Oregon; obtained on May 29, 1896, by Edward A. Preble, original No. 959.

_Range._--Southeastern Washington, eastern Oregon east of Cascades, northeastern California, central and northeastern Nevada, and southwestern Idaho. See fig. 46. Zonal range: Transition and Canadian.

_Description._--Size large; back from near Light Ochraceous-Buff to near Cinnamon-Buff, usually overlaid with black hairs forming broad dorsal band, which in some individuals is almost black; sides lighter than back, from near Light Pinkish-Cinnamon to near Cinnamon-Buff and Ochraceous-Buff, often with black hairs interspersed; lateral line faintly marked or wanting; belly pure white; tail bicolored, grayish-brown above and grayish-white to yellowish-white below; ears dark, edged with color of sides; palatal bridge long; interorbital region broad; inferior ramus of zygomatic process of maxillary usually with median projection; auditory bullae relatively small; incisive foramina greatly enlarged posteriorly; tooth-rows divergent anteriorly; nasals narrow posteriorly.

_Comparisons._--From _Zapus princeps curtatus_, _Z. p. oregonus_ differs as follows: Size averaging larger; upper parts darker; tooth-rows more divergent anteriorly; palatal bridge longer; mastoid region broader; incisive foramina relatively wider posteriorly.

For comparisons with _Zapus princeps cinereus_, _Zapus princeps pacificus_ and _Zapus princeps idahoensis_ see accounts of those subspecies.

_Remarks._--The coloration in _Z. p. oregonus_ varies somewhat from north to south. In the northern part of the range the average coloration of the upper parts is darker with more ochraceous on the sides. To the southward the upper parts are progressively paler and the sides are near Light Pinkish-Cinnamon. Because of this variation of color, and because of the small samples available to workers in the past, three populations of this subspecies have been named as distinct. However, with the large amount of additional material now available, the supposed diagnostic characters of these "forms" prove to be within the range of individual variations of each of several populations of which large samples are available.

_Zapus major_ Preble (1899:24) was described as having zygomata short, palate broad and long, incisive foramina large and elliptical, and color dark. Some specimens of _Z. p. oregonus_, from nearly all parts of its geographic range, show these same characters. Resemblances in anteriorly divergent tooth-rows, broad interorbital region, small auditory bullae, and posteriorly narrow nasals, are additional reasons for placing _Z.

major_ as a synonym of _Z. p. oregonus_.

_Zapus nevadensis_ Preble (1899:25), here considered a synonym of _Z. p.

oregonus_, was described as having: auditory bullae small, posterior border of the palate usually convex anteriorly, palatal bridge long, and color pale. These characters, however, are within the range of individual variation of _Zapus p. oregonus_. Similarities such as tooth-rows diverging anteriorly, nasals narrow posteriorly, interorbital region broad, and incisive foramina enlarged posteriorly are added reasons for placing _Z. nevadensis_ as a synonym of _Z. p. oregonus_.

_Zapus princeps palatinus_ Hall (1931:8) was described as having: palatal bridge long, incisive foramina wide posteriorly, posterior border of palate straight or convex posteriorly, and color pale. These characteristics are to be found in some individuals in most populations of _Z. p. oregonus_. Additional well marked cranial similarities, such as small auditory bullae, broad interorbital region, and nasals narrow posteriorly offer additional evidence as to the close relationship of _Z. p. palatinus_ and _Z. p. oregonus_. Hall (_loc. cit._), with a small sample available to him for comparative purposes (14 specimens of _Z. p.

palatinus_ and 12 specimens of _Z. p. nevadensis_), was impressed by the condition of the palate in _Z. p. palatinus_ and wrote: "the generally straight, or even posteriorly convex, posterior border of the palate seems to be unique among described forms of _Zapus_. The name _palatinus_ is given in allusion to this structural feature." With more than 300 specimens of _Z. p. oregonus_ available for study I find that a straight or posteriorly convex posterior border of the palate occurs in more than 50 per cent of the individuals examined. Specimens displaying this described palatal condition are known from all parts of the range of _Z. p. oregonus_, but do occur in a higher percentage of specimens in the area ascribed by Hall (_loc. cit._) to the range of _Z. p.

palatinus_.

Intergradation with _Zapus princeps idahoensis_ and _Zapus princeps cinereus_ is discussed in the accounts of those subspecies.

_Specimens examined._--Total, 340, distributed as follows:

CALIFORNIA: _Modoc Co._: Buck Creek R. S., 1 (CAS); _Willow Ranch_, 4 (CAS); _Sugar Hill, 5000 ft._, 1 (MVZ); _Goose Lake Meadows, near Sugar Hill_, 4 (MVZ); _Parker Creek, Warner Mts., 5500 ft._, 18 (MVZ); _Dry Creek, Warner Mts., 4800 ft._, 3 (MVZ) _east face Warner Peak, Warner Mts., 8700 ft._, 1 (MVZ); _5 mi. NW Eagle Peak, 7000 ft._, 5 (MVZ); La.s.sen Creek, 1 (SDM); _Happy Camp_, 1 (CAS).

IDAHO: _Boise Co._: Bald Mtn. R. S., Boise Nat'l Forest, 10 mi. S. Idaho City, 7400 ft., 2 (USBS). _Elmore Co._: Trail Creek, Boise Nat'l Forest, 2 (USBS). _Washington County_: 1 mi. NE Heath, SW Slope Cuddy Mtn., 4000 ft., 20 (5 MVZ).

NEVADA: _Elko County_: _6 mi. SW Mountain City, Cobb Creek, 6500-6550 ft._, 44 (MVZ); _summit between heads of Copper and c.o.o.n creeks, Jarbidge Mts._, 18 (9 MVZ); _head of Ackler Creek, 6800 ft._, 2: Steel Creek, 7000 ft., 11 (4 MVZ); _summit of Secret Pa.s.s, 6200 ft._, 8; _south fork Long Creek, 7830 ft._, 4; Harrison Pa.s.s R. S., Green Mtn., Canyon, 6050 ft., 12. _Eureka County_: 4 mi. S Tonkin, Denay Creek, Roberts Mt's, 1 (MVZ). _Humboldt County_: _Martin Creek R. S._, 1 (MVZ); 13 mi. N Paradise Valley, 6700 ft., 19 (MVZ). _Lander County_: Kingston R. S., 7500 ft., 4 (MVZ). _Nye County_: Wisconsin Creek, 7000 ft., 12 (MVZ). _White Pine County_: Willow Creek, 2 mi. S Elko County line, Ruby Mts., 6500 ft., 24 (2 MVZ).

OREGON: _Baker Co._: East Pine Creek, 2-1/2 mi. NE Cornucopia, 6 (USBS); McEwen, 2 (USBS); _Bourne_, 7 (USBS). _Clackamas County_: _Marks Creek, 12 mi. N of Howard_, 2 (USBS); Howard, 2 (USBS). _Crook County_: _Ochoco R. S., 4000 ft._, 4 (MVZ). _Grant Co._: _Austin_, 2 (USBS); _Cold Spring, 4900 ft., 8 mi. E Austin_, 4 (MVZ); Beech Creek, 1 (USBS); _Strawberry Mts._, 6 (USBS); _north fork Malheur River, 21 mi. SE Prairie City, 5000 ft._, 21 (MVZ). _Harney Co._: 10 mi. N. Harney, 1 (USBS); _Steen Mts., Keiger Gorge, 6900 ft._, 6 (USBS); Diamond, 4300 ft., 2 (USBS). _Jefferson Co._: Foley Creek, 12 mi. E Hay Creek, 1 (USBS). _Klamath Co._: Fort Klamath, 1 (USBS). _Lake Co._: Silver Creek, 7000 ft., Yamsey Mts., 1 (USBS); _2 mi. E Lakeview, 5200 ft._, 3 (MVZ).

_Malheur Co._: Jordan Valley, 4200 ft., 1 (USBS). _Umatilla Co._: Meacham, 1 (USBS). _Union County_: Elgin, 2 (USBS). _Wallowa Co._: Paradise, 10 mi. N Horse Creek, 7000 ft., 1 (USBS); _Minam Lake_, 1 (USBS); _16 mi. S and 3 mi. E Lostine, 5500 ft._, 9 (MVZ); _west fork Wallowa River, 5000 ft., 2-1/2 mi. above Wallowa Lake_, 1 (FM); _near Wallowa Lake, 4500 ft._, 3 (FM). _Wheeler County_: 11 mi. W and 7 mi. S Mitch.e.l.l, 4850 ft., 20 (MVZ).

WASHINGTON: _Asotin Co._: Anatone, 3300 ft., 1 (USBS). _Columbia County_: Twin b.u.t.tes, 25 mi. SE Dayton, Blue Mts., 2 (MVZ); _Stayawhile Spring, 5150 ft._, 4 (MVZ).

_Marginal records._--Washington: Anatone, 3300 ft. Oregon: East Pine Creek, 2-1/2 mi. NE Cornucopia. Idaho: 1 mi. NE Heath, SW slope Cuddy Mtn., 4000 ft.; Bald Mtn., R. S., Boise Nat'l Forest, 10 mi. S. Idaho City, 7400 ft.; Trail Creek, Boise Nat'l Forest. Nevada: Harrison Pa.s.s R. S., Ruby Mts.; Steel Creek, 7000 ft.; Wisconsin Creek, 7000 ft.; 13 mi. N Paradise Valley, 6700 ft. California: La.s.sen Creek; Buck Creek R.

S. Oregon: Fort Klamath; Howard; Meacham. Washington: Twin b.u.t.tes, 25 mi. SE Dayton, Blue Mts.

=Zapus princeps pacificus= Merriam

_Zapus pacificus_ Merriam, Proc. Biol. Soc. Washington, 11:104, April 26, 1897; Preble, N. Amer. Fauna, 15:30, August 8, 1899.

_Jaculus hudsonius_, Baird, Repts. Expl. and Surv. 111 8 (pt. 1):433, July 14, 1858 (part--the part from Canoe Creek, California).

_Zapus alleni_ Elliot, Field Columbian Mus., publ. 27, zool. ser., 1:212, April 19, 1898, type from Pyramid Peak, Lake Tahoe, El Dorado County, California.

_Zapus trinotatus alleni_, Elliot, Field Columbian Mus. Publ. 91, zool. ser., 3:315, July 5, 1904; Preble, N. Amer. Fauna, 15:27, August 8, 1899.