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); Assineau 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); 21/5 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); Basswood 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.
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 sparse 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 americanus 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. americanus 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. americanus in color, but cranially are most nearly like Z. h. intermedius and are assigned to that subspecies.
Two specimens from southern Illinois (Perry County) are intergrades between Z. h. pallidus and Z. h. intermedius. Cockrum 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 Cass and southern Clearwater counties, Minnesota, show such intergradation but are here considered to be Z. h. intermedius.
Specimens examined.—Total, 199, distributed as follows:
Illinois: Coles Co.: Fox Ridge State Park, 1 (UIM). Fulton Co.: 1/2 mi. N Norris, 2 (UIM); 3 mi. N Canton, 1 (UIM); 21/2 mi. N Canton, 2 (UIM); 2 mi. NW Canton, 3 (UIM); 2 mi. W Canton, 1 (UIM); 3 mi. SW Monterey, 1 (UIM). Jo Daviess Co.: near Galen, 3 (FM). Kane Co.: Sugar Grove, 1 (Chic. AS). Lake Co.: Fox Lake, 4 (FM); Pistake Bay, 1 (FM). Perry Co.: 6 mi. S Pinckneyville (near Pyatt), 2 (SITC). Vermilion Co.: Kickapoo State Park, 2 (UIM); Jordan Creek, 3 mi. NE Fairmont, 5 (UIM).
Indiana: Owen Co.: La Fayette, 1 (USNM). Parks Co.: Turkey Run State Park, 2 (1 UM; 1 UIM). Posey Co.: Hovey Lake, 1 (UM); New Harmony, 2 (Clev. MNH); no exact locality, 2 (UM). Sullivan Co.: no exact locality, 1 (UM).
Iowa: Dickinson Co.: Camp Forester, E Okeboji Lake, 3 (ISC). Emmet Co.: Fort Defiance State Park, 1 (ISC). Hamilton Co.: Little Wall Lake, Jewell, 6 (ISC). Ida Co.: Arthur, 1 (ISC). Lyon Co.: Elgin Township, Sec. 35, 2 (ISC); Riverside Township, Sec. 28, 1 (ISC). Palo Alto Co.: Ruthven, 1 (ISC). Sioux Co.: Ireton, 1 (UM). Story Co.: Ames, 1 (ISC). Winneshiek Co.: Decorah, 3 (UM); Ridgeway, 11 (UM); Conover, 3 (UM).
Kentucky: Lyon Co.: no exact locality, 1 (USNM).
Montana: Dawson Co.: Yellowstone River, 7 mi. NE Glendive, 2000 ft., 1 (MVZ).
Minnesota: Cass County: Cass Lake, 7 (USBS). Clearwater Co.: Itasca Park, Biological Station, 5 (UM). Grant Co.: 3 mi. NW Barrett, 1 (UM). Jackson Co.: 4 mi. E Heron Lake, 1 (UM). Ottertail Co.: 5 mi. NW Vergas, 8 (UM); 4 mi. NW Ashley, 1430 ft., 2. Ramsey Co.: St. Paul, 1 (UM). Sherburne County: Elk River, 23 (2 UM; 6 MVZ; 3 USBS). Winona County: La Crescent, 3 (USBS).
North Dakota: Cass County: Fargo, 1 (USBS). Dickey County: Ludden, 1 (USBS); Ellendale, 1 (USBS). Kidder County: Pettibone, 3 (Chic. AS). La Moure County: La Moure, 1 (USBS). Oliver County: Fort Clark, 3 (USBS). Pembina County: Pembina, 2 (USNM). Ramsey County: Devils Lake, 3 (USBS). Ramson County: Lisbon, 1 (USBS). Richland County: Wahpeton, 2 (USBS); 5 mi. NE Fairmont, Sioux River, 5 (USBS); Blackner, 2 (USBS). Rolette County: Fish Lake, 2 (USBS). Sioux County: Cannon Ball, 4 (USBS). Williams Co.: Grinnell, 2 (USBS).
Wisconsin: Burnett County: Danbury, 1 (USBS). Chippewa County: Holcombe, 3 (USBS). Clark County: Withee, 4 (USBS); Worden Township, 2 (USBS). Crawford County: Lynxville, 1 (USBS). Dane Co.: Madison, 2 (OHIO). Dodge Co.: Horicorn Refuge, 2 (USBS). Juneau County: Mather, 1 (USBS). Marathon Co.: Rib Hill, 8 (USBS). Oconto County: Lakewood, 1 (USBS). Portage County: Stevens Point, 3 (USBS). Price County: Ogema, 2 (USBS). Rock County: Milton, 1 (USBS). Sauk County: Devils Lake, 1 (USBS). Sheboygan County: 8 mi. SW Mellen, 1 (USBS); Elkhart Lake, 1 (USBS). Walworth County: Delavan, Fosters Bridge, 1 (USBS); Turtle Lake, 1 (USBS). Wood Co.: Thorp Township, 2 (AMNH); Hewett Township, 4 (AMNH).
Marginal records.—North Dakota: Fish Lake; Pembina. Wisconsin: Danbury; Ogema; Lakewood. Illinois: Fox Lake. Indiana: La Fayette; New Harmony. Illinois: 6 mi. S Pinckneyville (near Pyatt). Iowa: Ames; Arthur; Ireton. Montana: Yellowstone River, 7 mi. NE Glendive, 2000 ft. North Dakota: Grinnell.
Zapus hudsonius ladas Bangs, Proc. New England Zool. Club, 1:10, February 28, 1899.
Type.—Female, adult, skin and skull, No. 4169, E. A. and O. Bangs Coll. (now in Mus. Comp. Zool.); Rigoulette, Hamilton Inlet, Labrador; obtained on July 18, 1895, by C. H. Goldthwaite.
Range.—Eastern Quebec north of Gulf of St. Lawrence, Labrador, and Newfoundland. See fig. 47. Zonal range: Canadian and Hudsonian.
Description.—Size medium; back relatively dark, near Ochraceous-Tawny with admixture of black-tipped hair; dorsal band relatively wide but not sharply defined against color of sides; side lighter than back, from near Ochraceous-Tawny to near Cinnamon and lined with black-tipped hair; lateral line distinct of clear Cinnamon-Buff or Light Ochraceous-Buff; underparts white, often suffused with Ochraceous-Buff; tail distinctly bicolored, dark brown to black above and yellowish-white to grayish-white below; ears dark, usually flecked with Tawny Ochraceous and edged with ochraceous; feet grayish-white above; [450] incisive foramina relatively short and broad; pterygoid fossae relatively broad; auditory bullae broad and well inflated; mastoid region relatively broad; zygomata relatively short; inferior arm of zygomatic process of maxillary relatively broad.
Comparison.—From Zapus hudsonius acadicus, which Z. h. ladas closely resembles, it differs in: Color darker, dorsal band much less distinct, underparts more frequently suffused with Ochraceous-Buff; auditory bullae relatively broader and more inflated; pterygoid fossae broader; zygomata averaging shorter; incisive foramina relatively shorter; inferior arm of zygomatic process of maxillary relatively broader.
From Zapus hudsonius canadensis, Z. h. ladas differs as follows: Color darker, more richly tawny, dorsal band less distinct; auditory bullae relatively shorter, more inflated; pterygoid fossae averaging broader; zygomata averaging broader; incisive foramina averaging longer.
Remarks.—This subspecies retains all of its diagnostic characters throughout nearly all parts of its geographic range. Specimens from Nova Scotia are like Z. h. ladas in their darker color and less distinct dorsal band, but in the remainder of their characters they are distinct and best referable to Z. h. acadicus.
Zapus h. ladas, with its relatively large size, poorly defined dorsal band, and broad, well inflated auditory bullae, is one of the better marked subspecies of the species Zapus hudsonius.
Specimens examined.—Total, 41, distributed as follows:
Labrador: Mahkovik, 1 (USNM); Etagaulet Bay, Lake Melvikl, 2 (USNM); 3 mi. above mouth of Naskaupi River, 1 (USNM); Northwest River, 6, (USNM); Cartwright, 1 (USBS); Muskrat Falls, Hamilton River, 1 (USNM); Hamilton River, Flour Lake, 3 (USNM); Hawke Harbor, 4 (USNM); Goose Bay, 3 (USNM); Niger Sound, Islet Bay, 1 (USNM); Red Bay, 5 (USNM); Mecklenburg Harbor, 2 (USNM); Mary Harbor, 1 (USNM).
Newfoundland: Hare Harbor, 3 (USNM).
Quebec: northwest Ungava, 1 (NMC); Moise Bay, 5 (NMC); Trout Lake, near Moise Bay, 1 (NMC).
Marginal records.—Labrador: Mahkovik; Red Bay. Newfoundland: Hare Harbor. Quebec: Trout Lake, near Moise Bay; northwest Ungava.
Zapus hudsonius pallidus Cockrum and Baker, Proc. Biol. Soc. Washington, 63:1, April 26, 1950.
Jaculus hudsonius, Baird, Repts. Expl. and Surv. 111, 8 (pt. 1):433, July 14, 1858 (part—the part from Platte River, Nebraska, and Cass County, Missouri).
Zapus hudsonius, Coues, Bull. U. S. Geol. and Geog. Surv. of the Territories, 2nd ser. No. 5:260, 1877 (part—the part from Platte River, Nebraska).
Zapus hudsonius campestris Preble, N. Amer. Fauna, 15:20, August 8, 1899 (part—the part from Columbus in Nebraska and Jackson County in Missouri).
Type.—Male, adult, No. 22953, Univ. Kansas Mus. Nat. Hist.; NW corner sec. 4, T. 12S, R. 20E, 51/2 mi. N, 13/4 mi. E Lawrence, Douglas County, Kansas; obtained on May 4, 1948, by E. Lendell Cockrum and Rollin H. Baker, original No. 916 of Cockrum.
Range.—Southern South Dakota, Nebraska, Kansas, Missouri, and northeastern Oklahoma. See fig. 47. Zonal range: Upper Austral (Upper Sonoran and Carolinian).
Description.—Size small; back near Cinnamon-Buff with admixture of dark-tipped hair forming distinct, broad, dorsal band; sides bright Cinnamon-Buff with sparse mixture of dark-tipped hair; lateral line usually distinct, of clear Cinnamon-Buff; belly white, sometimes with suffusion of color of sides, tail bicolored, brownish to brownish-black above, grayish-white to yellowish-white below; ears dark, narrowly edged with color of sides; feet white to grayish-white above; mastoid region relatively narrow; maxillary tooth-row relatively short; zygomata relatively short; zygomatic arch relatively broad; interorbital region relatively broad; auditory bullae relatively small and narrow; lateral margins of nasals not constricted posteriorly.
Comparisons.—From Zapus hudsonius preblei, Z. h. pallidus differs as follows: Coloration brighter and richer, more buff, less black; zygomatic arch more broadly bowed; condylobasal length averaging less; braincase narrower; interorbital region broader; incisive foramina shorter.
For comparisons with Zapus hudsonius pallidus and Zapus hudsonius intermedius see accounts of those subspecies.
Remarks.—The characters that distinguish this jumping mouse from neighboring kinds are relatively stable throughout most of its geographic range. Zapus hudsonius pallidus is one of the best defined subspecies of Z. hudsonius.
One specimen from Batesland, South Dakota, is referred to Z. h. pallidus but shows evidence of intergradation with Zapus hudsonius campestris in the shape of the nasals, incisive foramina, and in breadth of the zygomatic arch. An animal from 3 mi. NE Ponca, Nebraska, is intermediate between Z. h. pallidus and Zapus hudsonius intermedius in size and shape of the auditory bullae and in the breadth of the pterygoid fossae, but since this individual shows more resemblance to Z. h. pallidus in coloration and in the majority of cranial characters it is here referred to Z. h. pallidus. Specimens from Beemer, Nebraska, show an intergrading tendency toward Zapus hudsonius intermedius in the reduced lateral bowing of the zygomatic arch and in shorter zygomata. Since these individuals resemble Z. h. pallidus in the majority of characters they are referred to that race. An individual of Z. h. pallidus from Pevely, Missouri, is to some extent an intergrade with Z. h. intermedius of neighboring southern Illinois. Two individuals of Z. h. pallidus from Mohawk Park, Oklahoma, are darker dorsally than, but otherwise similar to, specimens from the type locality.
Zapus hudsonius pallidus seems to be the terminus of a cline; this is a southward trend toward smaller size and lighter, brighter color. There is a similar clinal tendency in the jumping mice in eastern North America, and Z. h. americanus from North Carolina, pronouncedly resembles Z. h. pallidus from Kansas.
Specimens examined.—Total, 44, distributed as follows:
Kansas: Brown Co.: Horton, 1. Douglas Co.: Sec. 8, T. 123, R. 20E, 51/2 mi. N, 13/4 mi. E Lawrence, 10; 5 mi. N and 11/2 mi. E Lawrence, 3; Robinson Farm, 5 mi. N and 3 mi. E Lawrence, 2; 4 mi. N, 21/2 mi. E Lawrence, 1; Lakeview, 2; 71/2 mi. SW Lawrence, 1. Greenwood Co.: 1/2 mi. S Hamilton, 1.
Missouri: Cole Co.: Jefferson City, 2 (MO). Jackson Co.: no exact locality, 1 (USBS). Jefferson County: Pevely, 1 (USBS).
Nebraska: Blaine Co.: Dismal River, at Thomas-Blaine County line, 1 (NGFP). Boyd Co.: 2 mi. E and 15 mi. S Spencer, 1. Buffalo Co.: Platte Meadows, Kearney, 1 (HM). Butler Co.: 5 mi E Rising City, 1. Cherry Co.: Niobrara River, 18 mi. NW Kennedy, 1; Ballard Marsh, 20 mi. S Valentine, 1 (JKJ); Pony Lake Headquarters, Valentine Nat’l Wildlife Refuge, 1 (JKJ). Colfax Co.: 2 mi. S Schuyler, 1 (JKJ). Cuming County: Beemer, 4 (USBS). Dixon Co.: 3 mi. NE Ponca, 1. Platte County: Columbus, 1 (USBS). Richardson Co.: 5 mi. SE Rulo, 1 (NGFP).
Oklahoma: Tulsa Co.: Mohawk Park, 2 (UM).
South Dakota: Bennett Co.: Batesland, 1 (FM).
Marginal records.—South Dakota: Batesland. Nebraska: 3 mi. NE Ponca; Beemer; 5 mi. SE Rulo. Missouri: Pevely. Oklahoma: Mohawk Park. Kansas: 1/2 mi. S Hamilton. Nebraska: Platte Meadows, Kearney; Ballard Marsh, 20 mi. S Valentine; Niobrara River, 18 mi. NW Kennedy.
Type.—Male, adult, No. 73085, U. S. Nat. Mus., Biol. Surv. Coll.; Loveland, Larimer County, Colorado; obtained on July 23, 1895, by E. A. Preble, original No. 435.
Range.—Southeastern Wyoming and north-central Colorado. See fig. 47. Zonal range: Transition.
Description.—Size medium; color dull, back from near Clay Color to near Tawny-Olive with admixture of black hair forming poorly defined dorsal band; sides lighter than back from near Clay Color to near Cinnamon-Buff; lateral line distinct and clear Ochraceous-Buff; belly white, sometimes with faint wash of clear Ochraceous-Buff; tail bicolored, brownish to light brownish-black above, grayish-white to yellowish-white below; ears dark, narrowly edged with color of sides; feet grayish-white above; incisive foramina relatively narrow and elongate; auditory bullae moderately inflated; pterygoid fossae relatively broad; postpalatal notch broadly rounded; interorbital region relatively narrow; zygomatic arch not widely bowed; frontal region well inflated; distance from incisors to postpalatal notch relatively short.
Comparisons.—Among named subspecies, Zapus hudsonius preblei most closely resembles Z. h. campestris. From topotypes of Z. h. campestris, Z. h. preblei differs as follows: Upper parts generally dull, averaging lighter, less black-tipped hair; dorsal band less distinct; sides duller; averaging smaller in most cranial measurements taken; least interorbital constriction narrower; auditory bullae smaller, less well inflated; incisive foramina narrower, not truncate posteriorly; frontal region usually more inflated.
From Zapus hudsonius pallidus, Z. h. preblei differs as follows: Upper parts generally duller (less ochraceous); dorsal band less distinct; sides paler (not bright Ochraceous-Buff); zygomatic arch less widely bowed; least interorbital constriction narrower; occipitonasal length averaging greater; distance from [453] incisors to postpalatal notch averaging less; incisive foramina longer, proportionally less widely bowed; auditory bullae longer; pterygoid fossae averaging broader.
Remarks.—No evidence of intergradation with any other geographic race was noted. To the east the range of Z. h. preblei is separated from that of Z. h. pallidus (western Kansas and southwestern Nebraska), by several hundred miles of mixed and short grass prairie. Much of this area is unsuitable to jumping mice but local marshy places might be inhabited. Much territory inhospitable to Zapus intervenes also between the ranges of Z. h. preblei and Z. h. campestris. This area (northern Platte, Goshen, eastern Converse, Niobrara, and southern Weston counties, Wyoming) is chiefly rolling hills and short grass prairie and, like that to the east, is only locally suitable for Zapus. If jumping mice do occur in suitable places in these intervening areas it is to be expected that they will show intergradation between the subspecies concerned.
Zapus hudsonius preblei, on the basis of 11 specimens, agrees most closely in size and color with Z. h. campestris; there is much less resemblance between Z. h. preblei and Z. h. pallidus.
An adult from Springhill, 12 mi. N Laramie Peak, is typically Z. h. preblei as is one from Cheyenne.
Although specimens of Z. h. preblei are few (4 adult, 7 non-adults), the differences between this and neighboring named kinds is considerable.
Specimens examined: Total, 11, distributed as follows:
Colorado: Boulder County: 3 mi. E Boulder, 1 (UCM); 5 mi. E Boulder, 1 (UCM); south of Boulder (no exact locality), 1 (UCM). Jefferson County: Semper, 1. Larimer County: Loveland, 2 (USBS).
Wyoming: Albany County: Springhill, 12 mi. N Laramie Peak, 6300 ft., 3 (USBS). Laramie County: Cheyenne, 1 (USNM). Platte County: Chugwater, 1 (Clev. MNH).
Marginal records.—Wyoming: Springhill, 12 mi. N Laramie Peak, 6300 ft.; Chugwater; Cheyenne. Colorado: Loveland; Semper.
Zapus tenellus Merriam, Proc. Biol. Soc. Washington, 11:103, April 26, 1897.
Zapus hudsonius tenellus, Hall, Univ. California Publ. Zool., 40:377, November 5, 1934.
Zapus hudsonius hudsonius, Baker, Univ. Kansas Publ., Mus. Nat. Hist., 5:111, November 28, 1951 (part—the part from E side Minaker River, 1 mi. W Trutch and 3 mi. N Fort St. John, British Columbia).
Type.—Female, young adult, skin and skull, No. 66932 U. S. Nat. Mus., Biol. Surv. Coll.; Kamloops, British Columbia; obtained on August 25, 1894, by Clark P. Streator, original No. 4196.
Range.—British Columbia. See fig. 47. Zonal range: Canadian and Hudsonian.
Description.—Size medium; back from near Clay Color (brighter) to near Cinnamon-Buff with admixture of black tipped hairs forming a weakly defined dorsal band; sides lighter than back from near dull Ochraceous-Buff to near Cinnamon-Buff frequently with admixture of dark-tipped hairs; lateral line usually distinct, of clear Ochraceous-Buff; belly white sometimes with slight suffusion of Ochraceous-Buff; tail bicolored, brownish to brownish-black above, white or grayish-white to yellowish-white below; ears dark, edged and flecked on inner surface with color of sides; feet grayish-white above; auditory bullae relatively narrow, moderately inflated, elongate when viewed from below, anterior edge slightly concave; incisive foramina relatively short; braincase relatively narrow; vertical depth of skull at junction of frontals and nasals relatively great; nasals relatively narrow; pterygoid fossae moderately broad; zygomata relatively short.
Comparisons.—For comparisons with Zapus hudsonius hudsonius and Zapus hudsonius alascensis see accounts of those subspecies.
Remarks.—Merriam (1897a:103) named this jumping mouse as a full species, mentioning that the skull is similar in size and characters to that of Zapus hudsonius but that externally these animals differed in coloration and length of the tail. Hall (1934:377) treated Z. tenellus as a subspecies of Z. hudsonius. He observed that the difference between Z. tenellus, Z. h. alascensis, and Z. h. hudsonius was of the same degree, and, even though intergrading material was not known to him, he considered tenellus only subspecifically distinct from Z. hudsonius. Hall (loc. cit.) tentatively referred to Z. h. tenellus specimens from Indianpoint Lake, 15 mi. NE Barkerville, Cottonwood P. O., and Hazelton, British Columbia. I have seen and compared with the type of Z. tenellus all specimens examined by Hall and agree with him that they are best referred to Z. h. tenellus. Since 1934, several additional localities in British Columbia have yielded specimens. Those from Minaker River and Fort St. John are intermediate in dorsal coloration and in size and shape of the auditory bullae between Zapus hudsonius hudsonius and Z. h. tenellus but in all other characters are most nearly like Z. h. tenellus to which they are here assigned. These intergrades constitute additional evidence that Z. tenellus and Z. hudsonius are only subspecies of a single species.
Specimens examined.—Total, 17, all from British Columbia, distributed as follows: east side Minaker River, 1 mi. W Trutch, 1; Hazelton, 959 ft., 2 (MVZ); 5 mi. W and 3 mi. N Fort St. John, 1; Indianpoint Lake, 15 mi. NE Barkerville, 5 (MVZ); Cottonwood P. O., 3 (MVZ); S end Swan Lake, Vernon, 1200 ft., 2 (MVZ); Kamloops, 3 (USBS).
Marginal records.—British Columbia.—E side Minaker River, 1 mi. W Trutch; 5 mi. W and 3 mi. N Fort St. John; S end Swan Lake, Vernon, 1200 ft.; Kamloops; Hazelton, 959 ft.
Table 5.—Cranial Measurements (in Millimeters) of Zapus.