_Zapus hudsonius hudsonius_, Preble, N. Amer. Fauna, 15:15, August 8, 1899 (part--the part from Northwest Territory, Ontario, Michigan, northern Wisconsin and northern Minnesota).

_Zapus hudsonius alascensis_, Osgood, N. Amer. Fauna, 19:38, October 6, 1900.

_Type._--Type specimen not known to be in existence; from Hudson Bay, locality now considered to be Fort Severn, Ontario (see Anderson, 1942:37).

_Range._--Central Alaska southeastward to central Ontario, northern Minnesota, northern Wisconsin, and upper peninsula of Michigan. See fig.

47. Zonal range: Hudsonian, Canadian, and into Transition.

_Description._--Size medium; back dark, from near Tawny-Olive to near Cinnamon with heavy admixture of black hair forming dorsal band; sides lighter than back and from near Tawny-Olive to near Cinnamon, sometimes with admixture of black hair giving sides streaked appearance; lateral line usually distinct, clear Ochraceous-Buff; underparts white, sometimes with slight suffusion of Ochraceous-Buff; tail bicolored, brown to brownish-black above, grayish-white to yellowish-white below; ears dark, usually edged with ochraceous; feet grayish-white above; incisive foramina relatively short and broadly rounded; zygomata relatively short; braincase relatively broad; auditory bullae flat, long, and relatively broad; pterygoid fossae relatively narrow; nasals relatively broad and short.

_Comparisons._--From _Zapus hudsonius alascensis_, _Z. h. hudsonius_ differs as follows: upper parts generally darker, more black tipped hair; sides darker with greater suffusion of dark hair; lateral line brighter, more distinct; size averaging smaller; zygomatic arches less bowed outward; distance from incisors to postpalatal notch shorter; zygomata shorter; occipitonasal length less; mastoid region narrower.

From _Zapus hudsonius intermedius_, _Z. h. hudsonius_ differs in: color darker, more tawny dorsally; sides averaging darker, more black-tipped hairs; size averaging larger; braincase averaging broader; distance from incisors to postpalatal notch averaging slightly shorter; zygomata averaging longer; mastoid region averaging broader; incisive foramina averaging shorter.

From _Zapus hudsonius tenellus_, _Z. h. hudsonius_ differs as follows: upper parts averaging darker; tail averaging shorter; condylobasal length averaging more; braincase averaging broader; auditory bullae broader and less inflated; interparietal averaging broader; incisive foramina more broadly rounded and averaging longer.

For comparison with _Zapus hudsonius canadensis_ and _Zapus hudsonius campestris_ see accounts of those subspecies.

_Remarks._--Preble (1899:16) had available for study five specimens of _Zapus hudsonius hudsonius_ from Hudson Bay. Four were preserved in alcohol and one as an incomplete skin (prepared from an alcoholic specimen). All were unreliable for comparative purposes owing to the effects of the preservative. Preble, therefore, (_loc. cit._) selected as a fairly typical sample a series of specimens from Tower, St. Louis County, Minnesota; these formed the basis of comparison between _Z. h.

hudsonius_ and other subspecies of _Zapus hudsonius_. Now that additional material (well prepared skins and skulls) is available from the Hudson Bay region and from other localities in northern and western Canada it is evident that the specimens from Tower, although here considered to be _Z. h. hudsonius_, are not typical _Z. h. hudsonius_ but are intergrades between _hudsonius_ and specimens of _Zapus hudsonius intermedius_. Comparisons made in the present account are based on specimens from the vicinity of Hudson Bay (Fort Severen, Ontario, York Factory, Shamatawa River, and Robinson Portage, Manitoba).

These individuals are considered typical of this subspecies. With these new data available the range of _Z. h. hudsonius_ is now understood to include all of the region from eastern Alaska to the northern parts of Minnesota, Wisconsin, and Michigan.

Intergradation between _Zapus hudsonius canadensis_ and _Z. h.

hudsonius_ is noted in specimens from 30 mi. NE Port Arthur and also in those from Silver Islet, Thunder Cape, Ontario. These individuals resemble _Z. h. canadensis_ in size and shape of the auditory bullae and in the shape of the nasals, but in their darker coloration, broadly rounded incisive foramina, and relatively narrow pterygoid fossae they are more nearly like _Z. h. hudsonius_ to which they are here referred.

Specimens from Minaki, Ontario, are tending toward _Zapus hudsonius intermedius_ in lighter coloration but in the size and shape of the auditory bulla, size and shape of the incisive foramina, and in the width of the pterygoid fossae they are more nearly like _Z. h.

hudsonius_ to which they are here referred. Specimens from various localities in Menominee County, Michigan, are like _Z. h. intermedius_ in shape of the incisive foramina and shape of the postpalatal notch, but in color of pelage, size and shape of the auditory bullae, and breadth of the pterygoid fossae they closely resemble _Z. h. hudsonius_.

In Wisconsin, intergradation occurs in color and in cranial characters in specimens from Mercer, Solon Spring, and in a single individual from Ba.s.swood Lake. All these specimens, however, are best referable to _Z.

h. hudsonius_.

Specimens from one mile southwest of Fairbanks and from Fairbanks, Alaska, show intergradation with _Zapus hudsonius alascensis_ in coloration (more brown, less black), but in small size, short, broadly rounded incisive foramina, and in size and shape of the auditory bullae are nearest to _Z. h. hudsonius_ to which they are here a.s.signed.

Intergradation with _Zapus hudsonius alascensis_ is noted also in specimens from McIntyre Creek, Yukon. They are like _Z. h. alascensis_ in the size and shape of the auditory bullae and in the more elongate incisive foramina, but in the coloration, size of the pterygoid fossae, and breadth of the braincase are more nearly like _Z. h. hudsonius_ and are here referred to this geographic race.

In British Columbia, in specimens from 1 mi. NW junction of Irons Creek and Laird River as well as in those from Hot Springs, 3 mi. WNW junction of Trout River and Laird River, and in those from 1/4 mi. S of the junction of the same rivers, three way intergradation occurs. These animals are like _Zapus hudsonius alascensis_ in color and in length of tail. They agree with _Zapus hudsonius tenellus_ in shape of nasals. In degree of inflation of auditory bullae, in length and width of incisive foramina, and in shape of pterygoid fossae they are as in _Z. h.

hudsonius_ to which they are here a.s.signed.

_Specimens examined._--Total, 230, distributed as follows:

ALASKA: Fairbanks, 1 (USNM); _1 mi. SW Fairbanks, 440 ft._, 1.

ALBERTA: Conibear Lake, Wood Buffalo Park, 1 (NMC); a.s.sineau River, 1920 ft., 10 mi. E and 1 mi. N Kinuso, 1; Mountain Rapid, Athabasca River, 1 (USBS); _Brule Rapid, Athabasca River_, 1 (USBS); _25 mi. above Pelican Rapid, Athabasca River_, 1 (USBS); Lac la Nonne, 7 (NMC); _Swift Current, Athabasca River_, 1 (USBS); _junction Lac la Biche River and Athabasca River_, 1 (USBS); 30 mi. above Athabasca Landing, Athabasca River, 1 (USBS).

BRITISH COLUMBIA: 1 mi. NW junction Irons Creek and Laird River, 3; Hot Springs, 3 mi. WNW junction Trout River and Laird River, 1; _1/4 mi. S junction Trout River and Laird River_, 1.

MANITOBA: York Factory, 2 (USBS); Shamatawa River, 1 (USBS); Oxford House, 15 (USBS); _Robinson Portage_, 4 (USBS); _Echamamish_, 1 (USBS); Norway House, 1 (USBS); _Swan River_, 1 (NMC); Bird, 1 (NMC); _Aimie Lake_, 2 (NMC); Albert's Lake, Flin Flon, 2 (NMC); Portage La Prairie Prov., Delta, 1 (UM).

MACKENZIE DISTRICT: Fort Resolution, 3 (USBS); Fort Smith, 3 (USBS).

MICHIGAN: _Chippewa Co._: Marquette Nat'l Forest, 4; _no exact locality_, 2. _Gogebic Co._: Mud Lake, 1/4 mi. SE Thousand Island Lake, 2. _Keweenaw Co._: Lake Manganese, 1 mi. SSE Copper Harbor, 5 (UM); _2-1/5 mi. SE Copper Harbor_, 8 (UM); _5 mi. E Eagle Harbor_, 6 (UM); _E end Lake Upson_, 3 (UM); _Bete Grise_, 5 (UM). _Marquette County_: Michigamme, 3 (2 USBS). _Menominee Co._: _8 mi. N Hermansville_, 6 (UM); _6 mi. NW Banat_, 8 (UM); _5 mi. SW Banat_, 8 (UM); _8 mi. SW Banat_, 2 (UM); _7 mi. E Stephenson_, 3 (UM); _8 mi. WSW Stephenson_, 2 (UM); _10 mi. W Stephenson_, 2 (UM); _13 mi. WSW Stephenson_, 2 (UM); 5 mi. N Menominee, 2 (UM).

MINNESOTA: _Lake Co._: Splitrock River, 2 (UM); _St. Louis County_: Tower, 27 (USBS).

ONTARIO: Fort Severn, Kenora District, 6 (ROM); Minaki, 7 (MVZ); _30 mi.

NE Port Arthur_, 6 (UM); Silver Islet, Thunder Bay District, 4 (NMC); _20 mi. SW Fort Williams_, 3 (UM); _20 mi. SE Fort Williams_, 1 (UM).

SASKATCHEWAN: Emma Lake, 3 (ROM).

WISCONSIN: _Bayfield County_: _Herbster_, 4 (USBS); Brinks Camp, Washburn, 1 (AMNH); _Ba.s.swood Lake, 10 mi. SE Iron River_, 1 (USBS).

_Douglas County_: Solon Springs, 9 (USBS). _Forest County_: Crandon, 1 (USBS). _Iron County_: Mercer, 2 (USBS). _Oneida County_: _Crescent Lake_, 2 (USBS). _Vilas County_: _Mamie Lake_, 2 (USBS); _Lake St.

Germain_, 9 (USBS).

YUKON: Lake Lebarge, 3 (USBS); Forks of MacMillian River, 1 (USBS); McIntyre Creek, 2250 ft., 3 mi. NW Whitehorse, 4.

_Marginal records._--Alaska: Fairbanks. MacKenzie: Ft. Resolution.

Manitoba: York Factory. Ontario: Fort Severn, Kenora District; Silver Islet, Thunder Bay Dist. Michigan: Marquette Nat'l Forest; 5 mi. N Menominee. Wisconsin: Crandon; Solon Springs. Minnesota: Tower.

Manitoba: Portage la Prairie Prov., Delta. Saskatchewan: Emma Lake.

Alberta: 30 mi. above Athabasca Landing, Athabasca River; Lac la Nonne.

British Columbia: 1 mi. NW junction Irons Creek and Laird River. Yukon: McIntyre Creek, 2250 ft., 3 mi. NW Whitehorse; Lake Lebarge.

=Zapus hudsonius intermedius= new subspecies

_Type._--Male, adult, No. 83400, Univ. Michigan Mus. Zool.; Ridgeway, Winneshiek County, Iowa; obtained on July 22, 1939, by S. A. Hoslett, original No. 517.

_Range._--Eastern Montana, North Dakota, probably northern South Dakota, all but northern parts of Minnesota and Wisconsin, Iowa, Illinois, southwestern Indiana, and western Kentucky. See fig. 47. Zonal range: Upper Austral (Upper Sonoran and Carolinian) and Transition (Alleghanian and Transition).

_Description._--Size medium; back from near Warm Buff to near Ochraceous-Buff with admixture of hair tipped with black or dark brown usually forming distinct, broad, dorsal band; sides lighter, from near Warm Buff to near Ochraceous-Buff with spa.r.s.e mixture of dark-tipped hairs; lateral line often poorly marked but when present of clear Ochraceous-Buff; belly white, sometimes with slight suffusion of color of sides; tail bicolored, grayish-brown to brownish-black above, white to grayish-white or yellowish-white below; ears dark, narrowly edged with color of sides; feet white to grayish-white above; tail relatively short; lateral margins of nasals parallel; auditory bullae relatively short, broadly rounded, and moderately inflated; incisive foramina relatively long and narrow; pterygoid fossae relatively narrow; zygomata relatively long; inferior ramus of zygomatic process of maxillary frequently lacking a median projection.

_Comparisons._--From _Zapus hudsonius pallidus_, _Z. h. intermedius_ differs as follows: Coloration duller, not so bright, more yellow or buff and less bright Ochraceous-Buff; interorbital region averaging narrower; incisive foramina averaging longer and narrower; condylobasal length averaging greater; braincase averaging broader; mastoid region averaging broader.

For comparisons with _Zapus hudsonius hudsonius_, _Zapus hudsonius campestris_, and _Zapus hudsonius america.n.u.s_ see accounts of those subspecies.

_Remarks._--_Zapus hudsonius intermedius_ has a large geographic range.

There is some variation detectable when individuals from widely separate localities are compared, but where there is much variation it is obviously the result of intergradation. All characters differentiating _Z. h. intermedius_ from any contiguous subspecies are not present in every specimen even in the type series. Nevertheless, a certain series of cranial characters (narrow incisive foramina, short rounded auditory bullae, parallel lateral margins of nasals and narrow pterygoid fossae) is diagnostic.

Animals obtained from extreme southwestern Indiana and from eastern Illinois approach _Z. h. america.n.u.s_ in color and in shape of the incisive foramina, but in the shape of the nasals, width of the pterygoid fossae and breadth of the zygomata are most nearly like _Z. h.

intermedius_ to which they are here referred. Specimens from Lake and Kane counties, Illinois, also show affinity with _Z. h. america.n.u.s_ in color, but cranially are most nearly like _Z. h. intermedius_ and are a.s.signed to that subspecies.

Two specimens from southern Illinois (Perry County) are intergrades between _Z. h. pallidus_ and _Z. h. intermedius_. c.o.c.krum and Baker (1950:3) mentioned that these individuals showed evidence of intergradation with _Z. h. pallidus_ in color of the pelage and the breadth of the least interorbital constriction. In other characters the specimens are most nearly like _Z. h. intermedius_ to which they are here referred. Animals from Lyon County, Iowa, also show intergradation between _Z. h. pallidus_ and _Z. h. intermedius_. These individuals are most nearly like _Z. h. pallidus_ in interorbital breadth of the skull but in other characters agree with _Z. h. intermedius_ and, therefore, are referred to that subspecies.

Intergradation between _Z. h. campestris_ and _Z. h. intermedius_ is noted in a specimen from 7 mi. NE Glendive, Montana. This individual has the larger, broader, auditory bullae and more widely bowed incisive foramina of _Z. h. campestris_, but in color, in smaller external size, and in the majority of cranial characters it is best referred to _Z. h.

intermedius_.

Specimens from the north-central periphery of the geographic range of _Z. h. intermedius_ (northern Minnesota and Wisconsin) on the average are darker, have longer auditory bullae, wider bowed incisive foramina, and (some specimens) a slightly wider pterygoid fossa than is normal in more southern populations. This deviation from the norm is interpreted as intergradation between _Z. h. hudsonius_ and _Z. h. intermedius_.

Individuals from Burnett, Price, and Oconto counties, Wisconsin, and those from Ca.s.s and southern Clearwater counties, Minnesota, show such intergradation but are here considered to be _Z. h. intermedius_.