In the eastern part of the range of _Z. p. idahoensis_, intergradation occurs with _Zapus princeps minor_, as at 15 mi. S Heath, N Fork Flat Willow Creek, Big Snowy Mt's, Montana. Specimens from there have the lateral line enlarged and the maximum seen in this species of Ochraceous color ventrally. The pterygoid fossae are large and the bullae are reduced as in _Z. p. minor_, but in the sum total of the characters the mice more closely resemble _Z. p. idahoensis_. At Lewistown, 7 mi. NE Judith Mt's, Lime Kiln Gulch, Montana, the animals are colored as are _Z. p. minor_ but cranially are like _Z. p. idahoensis_ to which they are referred. Specimens from the Highwood Mt's, Montana, also are intergrades; they have a relatively distinct lateral line as in _Z. p.

minor_ but show no ventral suffusion of Ochraceous; they have large bullae, nasals that are straight in lateral profile and other cranial characters of _Z. p. idahoensis_ to which they are here referred.

A single specimen from Kamiak b.u.t.te, Whitman County, Washington, has been referred to _Z. p. idahoensis_ by Dalquest (1948:373). I have not seen this individual, but, on geographic grounds, it is likely to be of this subspecies.

_Specimens examined._--Total, 342, distributed as follows:

ALBERTA: Boom Creek, 5600 ft., 27 mi. W Banff, 2 (NMC); _Banff, Cascade Basin_, 2 (NMC); _Bryant Creek, Banff Park_, 1 (NMC); _Spray River, 7 mi. Cabin, Banff Park_, 3 (NMC); Crows Nest Pa.s.s, 2 (NMC); Waterton Lakes Park, 16 (NMC); _Linnets Pond, Waterton Lakes Park_, 4 (NMC); _Bertha Creek, Waterton Lakes Park_, 8 (NMC).

BRITISH COLUMBIA: Vermilion Crossing, Kootenay, 1 (ROM); Paradise Mine, 3 (PM); Crows Nest Pa.s.s, 4450 ft., 3 (NMC); Newgate, 10 (NMC).

IDAHO: _Adam Co._: 1/2 mi. E Black Lake, 6800 ft., 8; _summit of Smith Mtn., 7500 ft._, 9 (3 MVZ); 1 mi. N Bear Creek R. S., SW Slope Smith Mtn., 5400 ft., 13; New Meadows, 1 (USBS); _3 mi. W Payette, 5400 ft._, 4 (MVZ). _Blaine County_: _Perkins Lake, 7000 ft., Sawtooth Nat'l Forest_, 1; _Alturas Lake, 7000 ft._, 3 (MVZ); Prairie Creek, 12 mi. NW Ketchum, 2400 ft., 3. _Clearwater County_: 2 mi. NE Weippe, 3000 ft., 3 (MVZ). _Custer County_: Loon Creek R. S., 6000 ft., Challis Nat'l Forest, 2; _Head Pahsimeroi River_, 2 (MVZ); Mill Creek, 14 mi. WSW Challis, 8370 ft., 1 (MVZ). _Fremont County_: 7 mi. W West Yellowstone, 7000 ft., 3; _17 mi. E and 4 mi. N of Ashton, 6275 ft._, 9 (MVZ). _Idaho Co._: Packers Meadow, near state line, South Lobo Hot Springs, 5150 ft., 7 (USBS); _Warren_, 1 (USBS). _Kootenai Co._: 13 mi. E and 5 mi. N Coeur d'Alene, 5; _Cascade Creek, 36 mi. E Coeur d'Alene, Coeur d'Alene Nat'l Forest_, 1 (USBS). _Latah Co._: N Fork Potlatch River, 1 (USBS). _Lemhi County_: Salmon River Mts., 3 (USBS). _Shoshone Co._: Enaville 1 (USBS); _Glidden Lakes, 5700 ft._, 4 (MVZ). _Valley County_: 5 mi. E Warm Lake, 7000 ft., 6 (MVZ); _5 mi. W Cape Horn, 7000 ft., Sawtooth Range_, 1 (MVZ).

MONTANA: _Beaverhead County_: Birch Creek, 18 mi. NE Dillon, 7100 ft., 14 (MVZ). _Carbon Co._: _Pryor Mts._, 1 (USBS); 2 mi. E Shriver, 6500 ft., 6 (MVZ). _Cascade Co._: Neihart, 1 (USBS). _Chouteau Co._: _Upper Muddy_, 1 (USBS); Highwood Mts., 2 (USBS). _Fergus Co._: Lime Kiln Gulch, 7 mi. NE Judith Mts., 3 (USBS); 15 mi. S Heath, N Fork Flat Willow Creek, 8 (USBS); _10 mi. W Tyler, N Fork Flat Willow Creek_, 1 (USBS); _Crystal Lake, 6000 ft., Big Snowy Mts._, 3 (UM). _Flathead Co._: Waterton Lake, 1 (USBS); _Crosley Lake, Glacier Nat'l Park_, 1 (USBS); Paola, 1 (USBS); _Summit_, 2 (USBS); _1 mi. W and 2 mi. S Summit, 5000 ft._, 12. _Gallatin Co._: 4 mi S Logan, Camas Creek, Big Belt Mts., 5 (USBS); Gallatin Gateway, 5 (SDM); west fork West Gallatin River, 6500 ft., 6 (USBS). _Glacier Co._: Babb, 1 (LMH); _2-1/2 mi. W and 1-1/2 mi. S Babb, 4700 ft._, 1; _Many Glaciers, 4900 ft., Glacier Nat'l Park_, 5 (MVZ); _6 mi. S St. Marys, 6500 ft._, 1; _St. Marys Lake_, 7 (USBS); _McDermit Lake_, 1 (USBS); Blackfoot Agency, 1 (USBS).

_Golden Valley County_: _Swimming Woman Canyon, 3/4 mi. S Fergus County line, Big Snowy Mts._, 4 (UM). _Judith Basin Co._: _Little Belt Mts., Dry Wolf Creek, 20 mi. SW Stanford_, 4 (USBS); 13 mi. W Buffalo, 1 (USBS). _Madison Co._: 12 mi. SW Alder, Hinch Creek, Ruby Mts., 2 (USBS). _Meagher Co._: _16 mi. N White Sulphur Springs, Little Belt Mts._, 7 (USBS). _Park County_: _West Boulder Creek, 18 mi. SE Livingston_, 1 (USBS); Emigrant Gulch, 3 mi. SE Chico, 6500 ft., 4 (USBS); 2 mi. NE Cooke, 8000 ft., 22 (MVZ). _Ravalli County_: 3 mi. SW Florence, 3700 ft., 1; 6 mi. E Hamilton, 3700 ft., 1. _Sanders Co._: Prospect Creek, near Thompson, 1 (USBS). _Sweet Gra.s.s Co._: _near head of Big Timber Creek, 5200 ft., Crazy Mts._, 11 (USBS); Brannin Ranch, Sweet Gra.s.s Creek Canyon, 6 (UM); _Big Timber_, 1 (USBS). _Teton County_: 17-1/2 mi. W and 6-1/2 mi. N Agusta, 5100 ft., 2.

WYOMING: _Fremont County_: Moccasin Lake, 19 mi. W and 4 mi. N of Lander, 10,000 ft., 1; 23-1/2 mi. S and 5 mi. W Lander, 8600 ft., 4.

_Park County_: 31-1/2 mi. N and 36 mi. W Cody, 6900 ft., 7; _28 mi. N and 30 mi. W Cody, 7200 ft._, 1; _16-1/4 mi. N and 17 mi. W Cody, 5625 ft._, 14; 2 mi. S and 42 mi. W Cody, 6400 ft., 5; 12 mi. W Wapiti, 6 (LMH); _25 mi. S and 28 mi. W Cody, 6350 ft._, 5. _Sublette County_: E end Island Lake, 10,600 ft., 3 mi. S Fremont Park, 1; _N side Halfmoon Lake, 7900 ft._, 3; _W end Halfmoon Lake, 7900 ft._, 2; _10 mi. NE Pinedale, 8000 ft._, 1; _5 mi. E and 8 mi. N Pinedale, 7500 ft._, 1; 3 mi. E and 5 mi. N Pinedale, 7500 ft., 4; 19 mi. W and 2 mi. S Big Piney, 7700 ft., 3.

_Marginal records._--Alberta: Boom Creek, 5600 ft., 27 mi. W Banff; Crows Nest Pa.s.s; Waterton Lakes Park. Montana: Highwood Mts.; 15 mi. S Heath, N Fork Flat Willow Creek; 2 mi. E Shriver, 6500 ft. Wyoming: 23-1/2 mi. S and 5-1/2 mi. W Lander, 8600 ft.; 10 mi. W and 2 mi. S Big Piney, 7700 ft. Idaho: 7 mi. W West Yellowstone, 7000 ft.; Prairie Creek, 12 mi. NW Ketchum, 2400 ft.; 5 mi. W Warm Lake, 7000 ft.; 1 mi. N Bear Creek R. S., SW slope Smith Mtn., 5400 ft.; N Fork Potlatch River; 13 mi. E and 5 mi. N Coeur d'Alene. British Columbia: Newgate; Vermilion Crossing, Kootenay.

=Zapus princeps kootenayensis= Anderson

_Zapus princeps kootenayensis_ Anderson, Ann. Rept. Nat. Mus.

Canada for 1931:108, November 24, 1932.

_Zapus princeps princeps_, Preble, N. Amer. Fauna, 15:23, August 8, 1899 (part).

_Type._--Adult female, skin and skull, No. 10,020, Nat. Mus. Canada; near summit of Green Mountain, head of Murphy Creek, about 10 miles north of Rossland, West Kootenay district, British Columbia, at about, 6000 ft.; lat.i.tude 49 13' north, longitude 117 52' west; obtained on July 18, 1929, by R. M. Anderson, original No. 24.

_Range._--From Glacier in the Selkirk Range, British Columbia, south to 5 mi. W Cocolalla, Bonner County, Idaho, west and north to Sullivan Lake, Pend Oreille County, Washington; and northwestward to Manning Park on the eastern summit of the Cascade Range in British Columbia. See fig.

46.

_Description._--Size, medium; color moderately dark; upper parts noticeably dull and dusty; broad dorsal band of dull Ochraceous-Buff to near Warm Buff sprinkled with black hair to a varying degree, resulting in two color phases (dark has more black hair; Ochraceous phase or Warm Buff phase has more brown hair); sides paler than back owing to fewer black hairs; lateral line, when present, narrow and dull; ventral surface pure white; tail bicolored, pale brown above, yellowish-white to dull white below; ears dark with narrow white or yellowish-white edgings; feet white above; skull narrow across zygomata; incisive foramina narrow; bullae moderately inflated; nasals narrow at tips; postpalatal notch anterior to posterior face of last molars; braincase moderately narrow; zygomatic arch short.

_Comparisons._--From _Zapus princeps saltator_, _Z. p. kootenayensis_ differs as follows: Upper parts generally dull with less ochraceous; sides with more yellow, less ochraceous; lateral line wanting or not bright; skull averaging slightly smaller; incisive foramina smaller and narrower posteriorly; small medium projection on inferior ramus of the zygomatic process of maxillary frequently present instead of absent; pterygoid fossae shorter and narrower.

For comparison with _Zapus princeps idahoensis_ see account of that subspecies.

_Remarks._--This subspecies is paler and averages smaller than either of the subspecies with adjoining geographic ranges. There is intergradation with _Zapus princeps idahoensis_ in color, shape and size of incisive foramina, and in the shape of the nasals in Idaho-taken specimens from Glidden Lakes and Enaville. These individuals are thought to be _Z. p.

idahoensis_. Specimens from the same state taken at Cascade Creek and 13 mi. E and 5 mi. N Coeur d'Alene show intergradation in color, size and inflation of bullae, configuration of nasals, and shape of the vomer between _Zapus princeps idahoensis_ and _Z. p. kootenayensis_. The majority of characters studied show these animals to be referable to _Z.

p. idahoensis_.

Specimens from Monashee Pa.s.s, 4000 ft., British Columbia, show relationship to _Zapus princeps saltator_ in the posteriorly wide incisive foramina, in the narrow vomer, and, in some individuals, in the increased amount of ochraceous, dorsally and laterally. The majority of characters studied show these animals to be referable to _Z. p.

kootenayensis_.

The animals available from Glacier, British Columbia, are in color more nearly like _Z. p. saltator_ and cranially combine the characters of _Z.

p. idahoensis_, _Z. p. saltator_, and _Z. p. kootenayensis_. The sum total of their characters places them with _Z. p. saltator_. Anderson (1932:108) remarks on the disparity of size between the two s.e.xes of _Z.

p. kootenayensis_, stating that females are considerably larger than males. I have examined most of the material used in the original description and find that animals of like age in the two s.e.xes show no significant size difference. Anderson (_loc. cit._) seems to have compared young males with adult females.

_Specimens examined._--Total, 68, distributed as follows:

BRITISH COLUMBIA: Manning Park, 3 (PM); _Good Fellow Creek, Manning Park_, 1 (PM); _Mt. Beaver Valley, 6300 ft., Manning Park_, 1 (PM); _Timberline Valley, 6500 ft._, 3 (PM); _Allison Pa.s.s, 1 mi. E Manning Park_, 1 (PM); Monashee Pa.s.s, 4000 ft., 13 (PM); Hope-Princeton Summit, 5500 ft., 1 (NMC); _Hedley, Stirling Creek_, 1 (NMC); Anarchist Mts., 1 (PM); Fairview-Keremeos Summit, 5 (NMC); _Westbridge_, 2 (NMC); _Midway_, 2 (NMC); Green Mtn., near Rossland, 6000 ft., 12 (11 NMC, 1 MVZ); _Mt. Old Glory, 7000 ft., Rossland_, 5 (4 NMC, 1 MVZ); _Rossland, 5800 ft._, 12 (11 NMC, 1 MVZ); Camp 6, Meadow Creek, 7 mi. SE of Yahk, 1 (NMC).

IDAHO: _Bonner County_: 5 mi. W Cocolalla, 3500 ft., 2 (MVZ). _Boundary County_: 4 mi. W Meadow Creek, 3000 ft., 2 (MVZ).

_Marginal records._--British Columbia: Monashee Pa.s.s, 4000 ft.; Camp 6, Meadow Creek, 7 mi. SE Yahk. Idaho: 4 mi. W Meadow Creek, 3000 ft.; 5 mi. W Cocolalla, 3500 ft. British Columbia: Hope-Princeton Summit, 5500 ft.; Manning Park.

=Zapus princeps luteus= Miller

_Zapus luteus_, Miller, Proc. Biol. Soc. Washington, 24:253, December 23, 1911.

_Zapus luteus australis_, Bailey, Proc. Biol. Soc. Washington, 26:132, May 21, 1913. Type from Socorro, Socorro County, New Mexico.

_Type._--Female, adult, skin and skull, No. 133601, U. S. Nat. Mus.

Biol. Surv. Coll., Espanola, 5000 ft., Rio Arriba Co., New Mexico; obtained on June 24, 1904, by McClure Surber, original No. 162.

_Range._--White Mt's of southern Apache County and northern Greenlee County, Arizona; in New Mexico, from the Sacramento Mt's, Otero County, northward to the San Juan Mt's, Rio Arriba County. See fig. 46. Zonal range: Lower Sonoran (1 individual), Upper Sonoran, Transition, and Canadian.

_Description._--Size, small; back near Ochraceous-Buff, having black hair interspersed; mid-dorsal band not always well marked; sides Ochraceous-Buff with fine admixture of black hair; lateral line blending with Ochraceous-Buff of sides, not distinct; ventral surface white to base of hairs, in some cases lightly suffused with color of sides; tail indistinctly bicolored, tan to grayish-white below and brown above; hind feet grayish-white above; ears brownish, narrowly edged with Ochraceous-Buff; skull small; antorbital foramina relatively large; interorbital region broad; inferior ramus of the zygomatic process of the maxillary broad, often with medial projection; incisive foramina narrow posteriorly becoming broadly rounded anteriorly; palatal bridge relatively long; pterygoid fossae narrow; zygomatic arches relatively robust; nasals tapering at each end.

_Comparisons._--From _Zapus princeps princeps_, _Z, p. luteus_ differs as follows: Size, smaller; color lighter, more Ochraceous-Buff; ears lighter, edged with Ochraceous-Buff as compared with white or yellowish-white; lateral line indistinct or wanting as opposed to distinct; dorsal stripe not well defined; interorbital region broader; antorbital foramina relatively larger; zygomatic arches more robust; nasals tapering at each end as opposed to parallel sided; auditory bullae smaller, less inflated.

_Remarks._--The characters of this subspecies are relatively stable throughout most of its geographic range. Hall and Davis (1934:56) remarked that their material from the White Mountains of Arizona answered precisely to Miller's original description (1911:253) of the species, and my examination of these and other specimens from that area indicates the same thing except that the specimens average slightly darker mid-dorsally than those from New Mexico.

_Zapus luteus australis_, based on a single individual taken in a riparian thicket along the Rio Grande at Socorro, New Mexico, is referable to _Z. p. luteus_. The diagnostic characters, referred to in the original description, are as follows: Small, slender, and very narrow skull; especially narrow braincase; slender rostrum; and light dent.i.tion. These are expressions of age, rather than of geographic variation, in that the individual is a subadult (young of the year). The color, which is paler than in adults of _Z. p. luteus_, is almost identical with that of a subadult (No. 205585 USBS) from Alpine, Arizona. I can see no basis for recognition of _Z. p. australis_ and the name, therefore, is placed as a synonym of _Z. p. luteus_.

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.