Chapter IV: Part 4

From _Zapus princeps idahoensis_, _Z. p. princeps_ differs in: Size larger; darker with more Ochraceous-Buff; lateral line much more distinct; underparts frequently suffused with Ochraceous-Buff rather than seldom so; skull larger as regards length of palatal bridge, length of zygomatic arch, and width of proximal part of inferior ramus of zygomatic process of maxillary; pterygoid fossae broader; medial projection on inferior ramus of zygomatic process of maxillary large instead of reduced or absent; postpalatal notch usually anterior to, or on a plane with, posterior face of last molars rather than posterior to same.

_Remarks._--This subspecies retains most of its diagnostic characters in all parts of its geographic range. An individual from the type locality, Florida, Colorado, resembles _Zapus princeps luteus_ in color, but cranially is most nearly like _Z. p. princeps_. A specimen from Tierra Amarilla, New Mexico, a locality 25 miles north of, and in homogeneous habitat with, El Rito, New Mexico, from which specimens of _Z. p. luteus_ are known, shows resemblance to the latter in some cranial characters (see account of _Zapus princeps luteus_) but is most nearly like _Z. p. princeps_ to which it is referred.

Animals from Medicine Wheel Ranch, 9000 ft., 28 mi. E Lovell, Wyoming, which are here referred to _Z. p. princeps_, show intergradation with _Zapus princeps idahoensis_, being similar in size of pterygoid fossae, breadth of postpalatal notch, and in size and degree of inflation of the auditory bullae, but differ in color and in other cranial characters. Specimens from 2 mi. E Shriver, 6500 ft., Montana, which lack the distinct lateral line and ventral suffusion of Ochraceous-Buff, are here referred to _Z. p. idahoensis_.

_Specimens examined._--Total, 344, distributed as follows:

COLORADO: _Archuleta County_: _upper Navajo River_, 5 (CMNH); Navajo River, 6 (CMNH). _Boulder Co._: _12-1/2 mi. S Estes Park_, 2; _3 mi. S Ward_, 3; Gold Hill, 1 (USBS); _7 mi. NW Nederland's_, 2 (UM); _3 mi. E Pine Cliff_, 3 (CMNH). _Chaffee County_: _1-1/2 mi. S Monarch, 10,500 ft._, 2 (OKLA). _Conejos Co._: Antonito, 1 (USBS); _5 mi. S and 24 mi. W Antonito, 9600 ft._, 2. _Costilla Co._: _7 mi. SE Russell, 9200 ft._, 1 (MVZ); Fort Garland, 6 (USBS). _El Paso County_: Minnehaha, Half Way, 5 (UM). _Grand Co._: _Rocky Mtn. Nat'l Park_, 5 (UM). _Gunnison County_: Gothic, 10 (8 OKLA; 2 USBS); _Major Creek, foot of Monarch Pass_, 1 (OKLA). _Jackson Co._: Arapahoe Pass, Rabbit Ear Mts., 1 (USBS). _La Plata Co._: _7 mi. N Florida, Florida River, 7146 ft._, 8 (MVZ); Florida, 6500 ft., 11 (1 FM; 9 AMNH). _Larimer Co._: Elkhorn, 7000 ft., 1 (USBS); _19-1/2 mi. W and 2-1/2 mi. S Loveland, 7300 ft._, 3. _Mineral Co._: _Wasson Ranch, Creede_, 1; _3 mi. E Creede_, 1; _23 mi. S and 11 mi. E Creede, 9300 ft._, 5. _Rio Blanco Co._: _9-1/2 mi. SW Pagoda Peak, 7700 ft._, 5; Meeker, 1 (USBS). _Rio Grande County_: _Rock Creek Camping Area_, 1 (OKLA). _Saguache Co._: Saguache Park, Cochetopa Forest, 1 (USBS); _22 mi. W Saguache_, 1 (MVZ); _20 mi. S Saguache, Cochetopa Pass_, 1 (USBS). _San Juan County_: 6-1/2 mi. SW Silverton, 4.

NEW MEXICO: _Rio Arriba Co._: Tierra Amarilla, 1 (USBS). _Taos Co._: _Hondo Canyon, 8200 ft., west slope Taos Mts._, 1 (USBS); east slope Taos Mts., 8800 ft., 1 (USBS).

WYOMING: _Albany County_: 32 mi. N and 12-1/2 mi. E Laramie, 6080 ft., 1; _30 mi. N and 10 mi. E Laramie, 6760 ft._, 1; _29 mi. N and 8-3/4 mi. E Laramie, 6420 ft._, 6; _2 mi. S Browns Peak, 10,600 ft._, 2; _3 mi. ESE Browns Peak, 10,000 ft._, 8; _8 mi. E and 4 mi. S Laramie, 8600 ft._, 2; _8 mi. E and 6 mi. S Laramie, 8500 ft._, 1; _1 mi. ESE Pole Mtn., 8350 ft._, 2; _1-1/2 mi. ESE Pole Mtn., 8200 ft._, 1; _2 mi. SE Pole Mtn., 8300 ft._, 3; Centennial, 8120 ft., 1. _Big Horn County_: Medicine Wheel Ranch, 9000 ft., 28 mi. E Lovell, 36; _12 mi. E and 2 mi. N Shell, 7500 ft._, 13; _17 mi. E and 3 mi. S Shell, 9000 ft._, 1; _17-1/2 mi. E and 4-1/2 mi. S Shell, 9100 ft._, 6. _Carbon County_: Bridgers Pass, 18 mi. SW Rawlins, 7500 ft., 6; _Lake Marie, Medicine Bow Nat'l Forest, 10,400 ft._, 6; _14 mi. E and 6 mi. S Saratoga_, 5; _10 mi. N and 10 mi. E Encampment, 8000 ft._, 1; _10 mi. N and 12 mi. E Encampment, 7200 ft._, 2; _10 mi. N and 14 mi. E Encampment, 8000 ft._, 28; _9 mi. N and 3 mi. E Encampment_, 2; _8 mi. N and 8 mi. E Encampment, 8900 ft._, 1; _8 mi. N and 14 mi. E Encampment, 8400 ft._, 5; _8 mi. N and 14-1/2 mi. E Encampment, 8100 ft._, 12; _8 mi. N and 16 mi. E Encampment, 8400 ft._, 6; _8 mi. N and 22 mi. E Encampment, 10,000 ft._, 1; _8 mi. N and 19-1/2 mi. E Savery, 8800 ft._, 12; _8 mi. N and 20 mi. E Savery, 8800 ft._, 1; _7-1/2 mi. N and 18 mi. E Savery, 8400 ft._, 2; _7-1/2 mi. N and 18-1/2 mi. E Savery, 8400 ft._, 1; _7 mi. N and 18 mi. E Savery, 8400 ft._, 2; _6 mi. N and 13-1/2 mi. E Savery, 8400 ft._, 6; _6 mi. N and 14 mi. E Savery, 8350 ft._, 6; 4 mi. N and 8 mi. E Savery, 7300 ft., 1. _Converse County_: 21 mi. S and 24 mi. W Douglas, 7400 ft., 6; _21 mi. S and 24-1/2 mi. W Douglas, 7400 ft._, 3; _21-1/2 mi. S and 24-1/2 mi. W Douglas, 7600 ft._, 15; _22-1/2 mi. S and 24-1/2 mi. W Douglas, 7600 ft._, 1; _23 mi. S and 25 mi. W Douglas, 7800 ft._, 7. _Johnson County_: _6-1/2 mi. W and 2 mi. S Buffalo, 5700 ft._, 4; _5-1/2 mi. W and 1-1/2 mi. S Buffalo, 5520 ft._, 3; _5-1/2 mi. W and 1 mi. S Buffalo, 4800 ft._, 1; 1 mi. W and 4/5 mi. S Buffalo, 4800 ft., 1. _Laramie County_: 5 mi. W and 1 mi. N Horse Creek P. O., 3. _Natrona County_: _2 mi. W and 7 mi. S Casper, 6370 ft._, 2. _Washakie County_: 9 mi. E and 5 mi. N Tensleep, 7400 ft., 2; 9 mi. E and 4 mi. N Tensleep, 7000 ft., 5.

_Marginal records._--Wyoming: Medicine Wheel Ranch, 9000 ft., 28 mi. E Lovell; 21 mi. S and 24 mi. W Douglas, 7400 ft.; 5 mi. W and 1 mi. N Horse Creek P. O. Colorado: Gold Hill; Minnehaha. New Mexico: E slope Taos Mts.; Tierra Amarilla. Colorado: Florida; 6-1/2 mi. SW Silverton; Meeker. Wyoming: Bridgers Pass, 18 mi. W Rawlins, 7500 ft.

=Zapus princeps saltator= J. A. Allen

_Zapus saltator_ J. A. Allen, Bull. Amer. Mus. Nat. Hist., 12:3-4,
March 4, 1899; Preble, N. Amer. Fauna, 15:31, August 8, 1899.

_Zapus princeps_, Preble, N. Amer. Fauna, 15:23, August 8, 1899
(part--the part from Glacier, British Columbia).

_Zapus hudsonius_, Kermode and Anderson, Rep. Prov. Mus. Nat. Hist.
for 1913:21, 1914.

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

_Type._--Female, subadult, skin and skull, No. 14408, Amer. Mus. Nat. Hist.; Telegraph Creek, British Columbia; obtained on August 23, 1897, by A. J. Stone.

_Range._--Southern Yukon and southeastern Alaska south in British Columbia, to Bella Coola Inlet and Glacier. See fig. 46. Zonal range: Canadian and Hudsonian.

_Description._--Size medium; back near Ochraceous-Buff, overlaid with black hairs forming dark dorsal band thickly flecked with ochraceous; sides lighter than back; lateral line usually distinct; belly pure white, sometimes faintly suffused with Ochraceous-Buff; tail bicolored, dark above and grayish-white below; hind feet grayish-white above; ears dark, edged with yellowish-white or Ochraceous-Buff; incisive foramina long, broad posteriorly; palatal bridge relatively short; postpalatal notch anterior to posterior border of last molars; proximal part of inferior ramus of zygomatic process of maxillary without enlarged median projection; zygomatic arch short.

_Comparisons._--For comparison with _Zapus princeps kootenayensis_ and _Zapus princeps idahoensis_ see accounts of those subspecies.

_Remarks._--The geographic range of _Z. p. saltator_, as here understood, includes several localities heretofore considered to be within the geographic ranges of neighboring subspecies. Specimens from Indianpoint Lake, 15 mi. N of Barkerville, British Columbia, for example, which Hall (1934:379) considered nearer _Z. p. princeps_, are here referred to _Z. p. saltator_, with which they closely agree in cranial measurements and color of pelage. One individual from Glacier, British Columbia, thought to be _Z. p. princeps_ by Preble (1899:32), is here considered to show intergradation between _Z. p. kootenayensis_ and _Z. p. saltator_ but is more nearly like _Z. p. saltator_ to which it is here referred. Intergradation between _Zapus princeps idahoensis_ and _Z. p. saltator_ is noted, in color and in shape and size of the incisive foramina, in a specimen from Vermilion Crossing, Kootenay, British Columbia. The majority of cranial characters show these animals to be referable to _Z. p. idahoensis_. Specimens from Mt. Revelstoke, 3400 ft., British Columbia, show intergradation in shape of auditory bullae, in breadth of pterygoid fossae, and in shape and size of antorbital foramina between _Z. p. idahoensis_ and _Z. p. saltator_. Resemblance in pelage and in the majority of cranial characters indicates that these specimens are best referred to _Z. p. saltator_.

_Specimens examined._--Total, 187, distributed as follows:

ALASKA: Taku River, 1 (MVZ).

BRITISH COLUMBIA: Atlin, 7 (6 CAS; 1 PM); _Deep Creek, 60 mi. above Telegraph Creek_, 1 (USBS); _Sawmill Lake, near Telegraph Creek_, 6 (MVZ); junction 4 mi. N Telegraph Creek, 1 (ROM); McDame Post, Dease River, 1 (USBS); _Stikine River, at Glenora_, 28 (MVZ); _Kispiox Valley, 23 mi. N Hazelton_, 3 (MVZ); _9-mi. Mtn., 4500 ft., NE Hazelton_, 1 (MVZ); Hazelton, 959 ft., 20 (MVZ); Bear River, 7 mi. N Bear Lake, 1 (USBS); Charlie Lake, Fort St. John, 1 (PM); _Moose River_, 2 (PM); Tupper Creek, 7 (PM); _Babine_, 2 (USBS); _Port Simpson_, 3 (USBS); 12 mi. N Summit Lake, Alaska Highway, 3300 ft., 3 (NMC); _Giscome_, 1 (USBS); _Ootsa Lake_, 3 (PM); Inverness, mouth Skeena River, 1 (USBS); W end Eutsuk Lake, 1 (PM); Wapiti, head of Middle Branches River, 1 (USBS); Hagensborg, 15 (NMC); _Stuie, Cariboo Mtn., 4700 ft._, 2 (NMC); Rainbow Mts., Mt. Brilliant, 5000 ft., 10 (NMC); N 7 Wistaria P. O., 13 (NMC); _Mt. McLean, Lillooet_, 1 (PM); Mt. Robson P. O., Mt. Robson Park, 1 (MVZ); _Indianpoint Lake, 15 mi. NE Barkerville_, 42 (29 MVZ; 18 PM); Cottonwood P. O., 2 (MVZ); Mt. Revelstoke, 3400 ft., 6 (PM); Glacier, 1 (ROM).

YUKON: Rose River, mile 95 on Canol Road, 1 (NMC).

_Marginal records._--Yukon: Rose River, mile 95 on Canol Road, British Columbia; McDame Post, Dease River; Charlie Lake, Fort St. John; Tupper Creek; Wapiti, head of Middle Branches River; Mt. Robson P. O., Mt. Robson Park; Mt. Revelstoke, 3400 ft.; Cottonwood P. O.; Rainbow Mts., Mt. Brilliant, 5000 ft.; Inverness, mouth Skeena River. Alaska: Taku River. British Columbia: Atlin.

=Zapus princeps utahensis= Hall

_Zapus princeps utahensis_ Hall, Occ. papers, Mus. Zool., Univ.
Michigan, 296:3, November 2, 1934.

_Jaculus Hudsonius_, J. A. Allen, Bull. Essex Inst., 6:65, April,
1874 (part--the part concerning Great Salt Lake Valley, Utah).

_Zapus princeps princeps_, Wolfe, Jour. Mamm., 91:154, May 9, 1928.

_Zapus princeps idahoensis_, Davis, Recent Mammals of Idaho, Caxton
Printers, Caldwell, Idaho, p. 341, April 5, 1939 (part--the part
from southeast Idaho).

_Type._--Female, adult, skin and skull; No. 59153, Museum of Zoology, University of Michigan; Beaver Creek, 19 mi. S Manila, Daggett County, Utah; obtained on July 16, 1928, by A. and R. D. Svihla, original No. 176.

_Range._--Southeastern Idaho and extreme western Wyoming (Teton, Snake, and Uinta Mt's) southward through Uinta, Wasatch, Oquirrh, and Beaver Mt's of Utah. See fig. 46. Zonal range: Transition, Canadian, and Hudsonian.

_Description._--Size, large; back from Cinnamon-Buff to Warm Buff overlaid with black hairs; sides lighter with less admixture of black hairs; lateral line indistinct, sometimes wanting; tail bicolored, brownish-black above, white to yellowish-white beneath; feet grayish-white above; ventral surface white to base of hairs; ears dark, edged with white to yellowish-white; skull large; palatal bridge relatively short; upper tooth-rows diverging anteriorly; occipitonasal length great; interorbital region broad; zygomata widely bowed; postpalatal notch anterior to posterior face of last molars; mastoid width great.

_Comparisons._--From _Zapus princeps princeps_, _Z. p. utahensis_ differs in: color dorsally and laterally less ochraceous, lacking broad lateral line; skull larger in every part measured, excepting length of palatal bridge and breadth of palate at M3; zygomata more bowed; upper tooth-rows more divergent anteriorly; postpalatal notch anterior to posterior border of last molars.

Compared with _Zapus princeps cinereus_, _Z. p. utahensis_ differs as follows: Size averaging larger; upper parts darker, Cinnamon-Buff not Pinkish-Buff; incisive foramina wider posteriorly; palate wider; zygomata more robust.

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

_Remarks._--_Zapus princeps utahensis_ most closely resembles the several subspecies in the Great Basin in its large size, widely bowed zygomata, and posteriorly broadened incisive foramina. Intergradation between _Z. p. utahensis_ and _Zapus princeps cinereus_, geographically the nearest of the Great Basin subspecies, is not known. Intergradation in color and cranial characters occurs between _Zapus princeps idahoensis_ and _Z. p. utahensis_ in specimens from 17 mi. E and 4 mi. N of Ashton, Idaho. All these specimens are, however, referable to _Z. p. idahoensis_. Animals from 9 mi. SE Irwin and from 3 mi. SW Victor, Idaho, resemble _Z. p. utahensis_ in most differential characters (dorsally ochraceous, lateral line more distinct, incisive foramina large, palate broad anteriorly, auditory bullae less inflated), and are here referred to _Z. p. utahensis_. A series of specimens from the head of Crow Creek, Idaho, were considered by Davis (1939:340) to be intergrades between _Z. p. idahoensis_ and _Z. p. utahensis_; he thought that the specimens were more nearly like _Z. p. utahensis_ in color, but cranially (80 per cent in average ratio of anterior width of palate to posterior width of palate), more nearly like _Z. p. idahoensis_, to which subspecies he referred them. I have examined these specimens and find them to be more nearly like _Z. p. utahensis_ not only in color but in cranial characters as well. For example, the average ratio obtained by me for anterior width of palate to posterior width of palate is 72 per cent, rather than 80 per cent as given by Davis (_loc. cit._). Other cranial characters, size of the incisive foramina, shape of the foramen magnum, and shape of the auditory bullae, indicate relationship with _Z. p. utahensis_ to which they are here referred. Two immature individuals from Strawberry Creek, 20 mi. E Preston, Idaho, considered to be _Z. p. idahoensis_ by Davis (_op. cit._:341), also are here referred to _Z. p. utahensis_.

_Specimens examined._--Total, 178, distributed as follows:

IDAHO: _Bonnerville County_: _9 mi. SE Irwin, 6400 ft._, 3. _Caribou Co._: Head Crow Creek, Preuss Mts., 7500 ft., 6 (USBS). _Franklin County_: Strawberry Creek, 20 mi. NE Preston, 6700 ft., 2 (MVZ). _Teton County_: 3 mi. SE Victor, 6 (MVZ).

UTAH: _Beaver County_: Puffer Lake, 1 (UU). _Daggett County_: junction Deep Creek and Carter Creek, 7900 ft., 2 (UU). _Duchesne Co._: _Currant Creek, Uinta Forest_, 2 (USBS). _Morgan Co._: _exact locality not given_, 1 (UU). _Rich County_: 12 mi. SW Woodruff, 1 (MVZ). _Salt Lake County_: _Lambs Canyon, 2 mi. above Parleys Canyon, 7000 ft._, 1 (UU); _head Lambs Canyon, 9000 ft._, 3 (UU); _Salamander Lake and Lambs Canyon, 9000 ft._, 11 (UU); _"The Firs," Mill Creek Canyon_, 2 (UU); _Brighton, Silver Lake P. O., 8700 ft., Cottonwood Canyon_, 1 (UU); _Brighton, Big Cottonwood Canyon, 8000 ft._, 1 (UU); _1 mi. above Alta_, 4 (UU); Butterfield Canyon, approximately 5 mi. above Butterfield Tunnel, 3 (UU). _Sanpete Co._: _8 mi. E Fairview and 5 mi. S Mammoth R. S., Manti Nat'l Forest, 9000 ft._, 1 (USBS); _Baldy R. S., Manti Nat'l Forest_, 1 (UU); Ephraim, 8850 ft., 1 (USBS). _Summit County_: _Henrys Fork, Uinta Mts., 8000 ft._, 4 (UU); 14 mi. S and 2 mi. E Robertson, 9300 ft., 3. _Uintah County_: 21 mi. W and 15 mi. N Vernal, 10,050 ft., 1. _Utah County_: Payson Lake, 8300 ft., 12 mi. SE Payson, Mt. Nebo, 12 (UU); _1 mi. E Payson Lake, 8300 ft., Mt. Nebo_, 3 (UU). _Wasatch County_: Provo River, 3 mi. N Soapstone R. S., Wasatch Nat'l Forest, 1 (UU).

WYOMING: _Lincoln County_: 3 mi. N and 11 mi. E Alpine, 5650 ft., 37. _Teton County_: 1/4 mi. E Moran, 6700 ft., 4; _Bar B. G. Ranch, 6500 ft., 2-1/2 mi. NE Moose_, 11; _Moose, 6225 ft._, 1. _Uinta County_: 2 mi. E Robertson, 7200 ft., 1; _9 mi. S Robertson, 8000 ft._, 21; _9 mi. S and 2-1/2 mi. E Robertson, 8000 ft._, 1; _9-1/2 mi. S and 1 mi. W Robertson, 8600 ft._, 2; _10 mi. S and 1 mi. W Robertson, 8700 ft._, 18; _10-1/2 mi. S and 2 mi. E Robertson, 8900 ft._, 1; _13 mi. S and 1 mi. E Robertson, 9000 ft._, 4; _5 mi. E Lonetree_, 1 (ROM).

_Marginal records._--Wyoming: 1/4 mi. E Moran, 6700 ft.; 2 mi. E Robertson, 7200 ft. Utah: junction Deep Creek and Carter Creek, 7900 ft.; Paradise Park, 21 mi. W and 15 mi. N Vernal, 10,500 ft.; Ephraim, 8500 ft.; Puffer Lake; Payson Lake, 8300 ft., 12 mi. SE Payson, Mt. Nebo; Butterfield Canyon, approximately 5 mi. above Butterfield Tunnel. Idaho: Strawberry Creek, 20 mi. NE Preston, 6700 ft.; 3 mi. SW Victor.

=Zapus hudsonius= (Zimmerman)

(Synonymy under subspecies)

_Range._--From Pacific Coast of Alaska eastward to Atlantic Coast; from northern limit of tree-growth south into central Colorado and northeastern parts of Oklahoma and Georgia. See fig. 47.

Guide to subspecies

1. _Z. h. acadicus_ 6. _Z. h. hudsonius_
2. _Z. h. alascensis_ 7. _Z. h. intermedius_
3. _Z. h. americanus_ 8. _Z. h. ladas_
4. _Z. h. campestris_ 9. _Z. h. pallidus_
5. _Z. h. canadensis_ 10. _Z. h. preblei_
6. _Z. h. hudsonius_ 11. _Z. h. tenellus_]

_Externals._--Size small to medium (total length 188 mm to 216 mm); tail longer than head and body (112 mm to 134 mm) and bicolored, pale brown to brownish-black above, white to yellowish-white below; hind feet long (28 mm to 31 mm), grayish-white above; back ochraceous to dark brown; sides paler than back with dark hair interspersed; lateral line usually present but sometimes indistinct or entirely absent (when present usually clear Ochraceous-Buff); ventral coloration white, sometimes with suffusion of ochraceous; guard hairs average 115 microns (96u to 140u) in diameter; underhair with pigment pattern in form of hollow, narrow rectangles; cuticular scales of underhair large and fewer than those of the underfur of _Z. trinotatus_, but underhair of _Z. hudsonius_ otherwise resembles that of _Z. trinotatus_.

_Baculum._--Size small (total length 4.5 mm to 4.9 mm); base medium in width (0.64 mm to 0.72 mm); tip narrow (0.24 mm to 0.26 mm) and dished out in dorsal aspect, blunted; shaft rounded, curving gently upward at tip.

_Skull._--Small to medium and relatively narrow in relation to length; rostrum pointed and short; mastoid region relatively narrow; incisive foramina short; base of zygomatic process of squamosal narrow; coronoid process of mandible short, relatively weak. Upper premolar usually small (averaging .30 mm in length and .35 mm in breadth) sometimes functional (most often so in old adults), occlusal surface divided by single shallow re-entrant fold, which in worn teeth forms centrally located lake; tooth-row short as compared to that of other species; individual cheek-teeth usually smaller than those of other species; lower cheek-teeth shorter and narrower than those of other species; angle of mandible strongly inflected.

GEOGRAPHIC VARIATION

The species _Z. hudsonius_ is divisible into 11 subspecies based on differences in color, relative proportions of the tail, hind feet, body, and size and shape of parts of the skull (zygomata, braincase, incisive foramina, auditory bullae, pterygoid fossae, rostrum, and interorbital breadth).

Color of the pelage varies, as a general rule, from dark-backed, dull-sided individuals in the northern parts of the geographic range of the species to light-backed, bright-sided individuals in the southern parts of the range.

Individuals from the southernmost geographic races (_Z. h. americanus_ and _Z. h. pallidus_) are the smallest for the species and those from the northernmost subspecies (_Z. h. alascensis_) are the largest. One subspecies, _Z. h. campestris_, from the central part of the range of the species, however, seems to be out of the cline. This form inhabits the eastern foothills of the Rocky Mountains and is a robust animal approaching _Z. princeps_ in size.

Seemingly there is no clinal variation in the several qualitative features of the cranium, for instance in the shape of the auditory bullae, shape of the incisive foramina, and shape of the postpalatal notch. On the other hand, the dimensions of the entire skull show that the larger crania are of the northernmost subspecies and the smaller of the southernmost subspecies.

NATURAL HISTORY

_Habitat._--_Zapus hudsonius_ occurs in low undergrowth usually of grasses or forbs or both, in open coniferous forests, deciduous hardwood groves, or in stands of tall shrubs and low trees, but most frequently in open, moist areas.

Quimby (1951:75) notes that jumping mice were more common in the moist lowlands than in the drier uplands. More were in the open type lowlands than in the forested type, and these mice favored habitats normally bordered by small streams affording moist to semi-aquatic living conditions. The reports of Goodwin (1924:255), Christian (1936:416), G. S. Miller (1899:329), Cory (1912:249), Lyon (1936:277), Stoner (1918:123), and others, although concerning widely different parts of North America, indicate that _Z. hudsonius_ selects habitats in vegetation of like form, even though different assemblages of plant species may be involved.

An average of 11.91 mice per acre was recorded by Quimby (1951:91) from a study plot at Itasca Park, Clearwater County, Minnesota. He gives the monthly population densities per acre for _Z. hudsonius_ at Centerville, Anoka County, Minnesota, as follows: June 2.78, July 3.57, August 3.10, and September 1.81. Blair's (1940:248) data on bi-monthly population density per acre for _Z. hudsonius_ on the Edwin S. George Reserve, Livingston County, Michigan, are remarkably similar, when adjusted on a monthly basis, to those obtained by Quimby (_loc. cit._). Blair's (_loc. cit._) monthly population densities per acre are as follows: June 3.90, July 3.85, August 3.10, and September 2.00. Townsend (1935:90) estimated population densities per acre for _Z. hudsonius_ in central New York state, at 11 to 72 individuals. As Quimby (1951:92) points out, Townsend's figures are probably too high, as commonly is the case when the moving quadrat technique is used because animals from neighboring areas enter the trapped area to take over the niches made available by their predecessors' removal.

The population of _Z. hudsonius_ may vary considerably from year to year as well as seasonally. Blair (1940:249) found notably fewer jumping mice on the George Reserve in 1938 than in 1939. Quimby (1951:94) found the numbers of _Zapus_ to be highly variable and thought that there was a rapid turnover. Young animals were not caught until July when 25 per cent were either juveniles, young, or subadults; from this time on these age classes increased to a high of sixty-one per cent in September. Quimby (_loc. cit._) found that separating the individuals into their proper age classes was more difficult in September, since the young from early litters are adultlike in appearance. His data indicate as he remarked, "That the over-wintering adults are, for the most part, gradually replaced by the young of the year as the summer progresses."

The sexes in _Z. hudsonius_ vary only slightly from a one to one ratio. Quimby (1951:63) found a sex ratio of 110 females to 100 males and Blair (1940:245) records a sex ratio of 113 males to 100 females. Townsend (1935:42) records a sex ratio in central New York of 155 males to 100 females. Such a wide variation from a one to one ratio suggest that the moving quadrat technique, which Townsend (1935:90) employed in obtaining his data, may be, in some way unknown to me, more selective for the males.

_Behavior._--The saltatorial powers of _Z. hudsonius_ are well developed and often have been described in the literature. Stoner (1918:123) remarks that, "When disturbed _hudsonius_ moves away by a series of leaps ... the distance traversed in one of these leaps is from six to eight feet."; Cory (1912:249) observed these mice to make surprisingly long leaps, and, according to him, a distance of 10 feet is by no means unusual; Handley and Patton (1947:49) credit these animals with jumping eight to ten feet at a single bound; Hamilton (1935:190) remarked that he noted an average of not more than four to six feet per jump; Townsend (1935:91) observed one individual make jumps of about two feet; and Harper (1932:29) records a jumping mouse leaping for distances of two to three feet. Quimby (1951:72) notes that he had never seen one jump farther than three feet. He found that the greatest jumps occurred initially and normally covered a distance of two to three feet; subsequent leaps were shorter but more rapid. A jumping mouse in full retreat progressed by jumps of about one foot.

Statements concerning the gait of _Z. hudsonius_ are not in agreement but the consensus of opinion is that these animals when unfrightened progress by a series of hops of one to six inches, or, occasionally, with a slow creeping motion while the animal is on all fours. When frightened, however, their progress is by long bounds; the mice make a series of two or three such leaps to the nearest protective cover, and then sit motionless until pursued.

Concerning the use of the tail as a balancing organ, G. S. Miller (1899:330) describes the behavior of a jumping mouse from which the tail had been severed by the sickle of a mowing machine. "When I approached, it made violent efforts to escape, but the moment it was launched in the air, its body, deprived of its balancing power, turned end over end so that it was as likely as not to strike the ground facing the direction from which it had come."

Riparian animals such as _Z. hudsonius_ need enter the water to escape from enemies or perhaps in search of food. _Zapus hudsonius_ can and does swim. Hamilton (1935:190) found it to be a strong swimmer capable of remaining in the water for from four to five minutes. According to Hamilton (_loc. cit._), when the mouse is swimming the head is held high, the tail is arched near its middle, and only the hind limbs are employed in propulsion. According to Sheldon (1938:327), Philip Allan, in northern Minnesota, saw many _Z. hudsonius_ swimming three or four inches under the surface of the water. The mice swam upstream and only the hind legs were employed in the swimming movements. N. A. Preble (1944:200), at Archer's Pond, 3 miles southeast of Center, Ossipee County, New Hampshire, observed a jumping mouse swimming rapidly under water toward another portion of the shore 30 or 40 feet away. The mouse, swimming less than a foot beneath the surface, was vigorously using both forefeet and hind feet, but the long tail trailing limply behind, contributed in no way to the animal's movements. Quimby (1951:72) released five of the mice, one at a time, in the open water of a lake. He followed alongside in a boat and observed that, "In all instances the animals proved to be excellent swimmers both on and underneath the surface. The methods of progression were similar to land movements; i. e., the limbs were employed differently at various times depending upon the speed. When first placed in water they moved rapidly by lunges produced by sweeping strokes of the hind limbs employed simultaneously. This movement was accomplished similarly to the long jumps made on land ... Following the first excited lunges, they settled down to a steadier and slower gait using all four limbs one at a time. The anterior part of the body was held high in the water ... When approached too closely, they attempted to escape by diving. The maximum distance noted was about four feet ... One was able to swim vigorously for approximately three minutes after which it tired greatly and was in danger of drowning."

As concerns digging ability, Goodwin (1935:148) reports that _Z. hudsonius_ makes its own burrows; these are short and close to the surface in the summer but longer, deeper, and below the frost-line in winter. Two captives used their forefeet and nails in digging a tunnel in the foot of soil that Goodwin (_loc. cit._) had placed in their cage. Quimby (1951:72) remarks that captives excavate soil by means of the front feet and throw the soil out behind; as the burrow deepened the hind feet were also utilized to throw the loose soil out of the burrow.

_Zapus hudsonius_ climbs; Sheldon (1934:293) observed captive animals to climb over small evergreen trees in their cages. They moved with surprising sureness and agility, chasing each other among the branches or sitting for several minutes at a time on one of the limbs. Hamilton (1935:190) found that the mice ran over limbs and brush which were placed in their outdoor enclosure.

Ordinarily _Z. hudsonius_ is nocturnal, appearing in the early dusk and remaining active until pre-dawn. Occasional individuals are abroad in daylight hours. Sheldon (1934:293) found in Nova Scotia that _Z. hudsonius_ is most active from early dusk through the night, but that it may be abroad in daylight as well. Her statements are based on trapping results, field observations, and observations made on captive individuals. Quimby (1951:73) found that _Z. hudsonius_ in Michigan is mostly nocturnal; however, he saw mice on a few occasions in the daytime. Diurnal activity seems to be increased in cloudy or damp weather; Quimby (_loc. cit._) almost invariably trapped more of these mice on cloudy, damp days than on other days.

This jumping mouse usually is silent but does utter various sounds. Sheldon (1934:295) records squeaking and clucking noises. Quimby (1951:73) records the clucking noise described by Sheldon (_loc. cit._) and mentions also the squeaking and suckling sounds produced by the small young. This mouse is most vociferous when young or when about to go into hibernation. Sheldon (1938:327) writes that _Z. hudsonius_ makes a drumming noise by vibrating the tail against dry leaves.

Many data are available concerning the hibernation of _Z. hudsonius_. In general it seems necessary for the mice to put on a certain amount of fat preparatory to hibernation. This fat is deposited in a thin layer over the inside of the skin, over the back, and in the body cavities. The thickest deposits are in and about the inguinal region.

Quimby (1951:83) noted that gain in weight was accelerated in a brief period prior to entrance into hibernation. This relationship of rapid gain in weight to hibernation allows a person to estimate the date of hibernation. Cold weather seems to hasten hibernation, but less so than the correct physiologic condition which is foreshadowed by a rapid gain in weight. For example, Quimby's (1951:84) data reveal that mice that were moved to a heated room gained weight and hibernated in a fashion similar to those in unheated surroundings. Hamilton (1935:193) states that, "It seems necessary for the mouse to lay on a certain amount of fat before it is capable of hibernation." Hamilton (_loc. cit._) reported that 18 specimens of _Z. hudsonius_ taken [presumably in an active state] near Ithaca, New York, on November 13, were without a trace of fat.

Data that are available concerning the hibernation sites of _Z. hudsonius_ show that almost invariably these mice seek shelter in burrows beneath the surface of the ground and there construct nests of grass, leaves, or some other vegetation. Nicholson (1937:103) found a hibernating _Z. hudsonius_ on the George Reserve, Livingston County, Michigan, on October 20. The mouse was in a nest, composed of 10 to 12 damp elm leaves, in a sand bank two feet three inches vertically and three feet nine inches horizontally from the surface. On April 11, 1948, Schwartz (1951:228) found five nests (three with occupants) of _Z. hudsonius_ at Jefferson City, Cole County, Missouri. All nests were one foot beneath the surface of a pile of coal-ash, which was about three and one-half feet high and five feet in diameter. The nests were spherical, approximately four inches in diameter and consisted of dried oak leaves and bits of dried grass. Grizzell (1949:74) found two hibernating jumping mice at the Patuxent Research Refuge, Laurel, Maryland, in January, 1948. The mice were in separate woodchuck dens; one mouse was 40 inches below the surface and the other was 26 inches below the surface. The mice were curled up in the center of masses of dead leaves, and thus, were well insulated against the cold. On April 29, 1944, at Ithaca, New York, Eadie (1949:307) uncovered a hibernating jumping mouse. The nest, about the size of a baseball, was compactly made of fine grasses and was 10 inches below the surface of the ground in a mound of earth that was approximately six by four feet at the base and three feet high.

From the foregoing reports on hibernation sites it is evident that well drained areas are utilized. Sheldon (1934:300) remarks that the burrows used for hibernating are dug in a bank or some place from which the rain water and melted snow probably drains off.

Eadie (1949:307), Grizzell (1949:75), Sheldon (1934:299), Schwartz (1951:228), and Sheldon (1938:331) all agree that the hibernating mouse rolls up into a ball-like shape (resting on its head and pelvis) with the head between the hind legs, the nose against the lower belly, the forefeet curled on the chest, and the tail curled around the head and body.

A marked loss of weight occurs immediately after hibernation begins, and then reduction in weight is slow and regular. (See Hamilton, 1935:194 and Quimby, 1951:84.)

Sheldon (1934:297) cites a letter from Vernon Bailey in which he remarks on the necessity of abundant moisture and saturate air for hibernating jumping mice. Bailey writes "... they will awaken at times famished for water and will drink and drink before going back to sleep."

Hamilton (1935:195) thinks that in the Ithaca area of New York these mice probably leave their winter quarters in the second half of April and that in southern New York and Long Island they emerge considerably earlier. Quimby (1951:82) and Bernard Bailey (1929:163) report that males appear earlier in the spring than do the females. Quimby (_loc. cit._), by recording the sequence and dates of phenological events and appearance of _Zapus_ in several years, was able to predict fairly accurately the time of emergence of _Zapus_ in a succeeding year. In Minnesota, jumping mice emerged late compared to other hibernating rodents.

_Enemies._--V. Bailey (1927:119) reports that A. K. Fisher found 50 skulls of _Zapus_ in barn owl pellets taken from the towers of the Smithsonian Institution, Washington, D. C. Dearborn (1932:32) reported mink as having fed on jumping mice. Surface (1906:197) records taking a _Zapus_ from the stomach of a rattlesnake. Pearson and Pearson (1947:138) found remains of _Z. hudsonius_ in pellets of barn owls. Quimby (1951:74) reports two cases of predation on _Z. hudsonius_; one was by a northern pike, _Esox lucius_ Linnaeus and the other was by a weasel, _Mustela_ sp. Vergeer (1948:91) collected a green frog, _Rana clamitans_ Latreille, which had eaten a jumping mouse.

Quimby (1951:74) frequently found the fleas, _Megabothris quirini_ Rothschild, and _Megabothris wagneri_ (Baker), and occasionally a larval tick, _Dermocenter variabilis_ (Say), on _Z. hudsonius_. Sheldon (1934:296) remarks that captive animals are burdened with numerous fleas. Hamilton (1935:191) removed a louse from a jumping mouse. One mouse had a hole in the throat and three others had holes in the inguinal region; presumably bot-flies had emerged from these holes. Test (1943:507) found a single _Cuterebra_ larva in the inguinal region of a _Z. hudsonius_, and Sheldon (1938:328) found _Z. hudsonius_ infested by larvae of _Cuterebra fontinella_ Clark. Here, as in other cases, these larvae were found immediately below the skin. Erickson (1938:252) examined 18 _Z. hudsonius_ obtained in Minnesota, and found that three were parasitized. He found a bot-fly larva, _Cuterebra_ sp., nematodes of the genera _Subulura_ and _Spirocerca_, and a fluke of the genus _Notocotylus_.

_Food._--Quimby (1951:85-86) studied the food preferences, by presenting to caged _Z. hudsonius_ the plants and invertebrate animals normally available to these mice in nature, and indicates that in general, the starchy fruits of the Gramineae and the less fleshy fruits of various groups of plants are more heavily utilized than other plant materials. His observations indicate that these rodents are highly insectivorous and that they consume many insects under natural conditions. Goodwin (1935:148) reports that the stomach contents of several individuals obtained at South Woodstock, Connecticut, consisted exclusively of blackberries, and that others had subsisted principally on cranberries. Hamilton (1935:197) remarks that seeds are the favored food but that berries, nuts, fruits of various kinds, roots, and insects are also utilized. Stoner (1918:123) writes that the food in cultivated areas of Iowa is various grains as well as grass and weed seeds; in wooded places the mice feed on seeds and nuts of trees. Vernon Bailey (1927:118) states that the examination of a great many stomachs of these jumping mice [in North Dakota] revealed nothing "but the fine white pulp of carefully shelled, well-masticated seeds. Generally these are from grasses, although grain and a variety of other plant seeds are eaten." Schmidt (1931:116) examined the stomach contents of several _Z. hudsonius_ taken in Clark County, Wisconsin, and in most stomachs found the remains of finely chewed roots; however, two from Hewett had eaten several geometrid caterpillars.

Lyon (1938:279), Stoner (1918:123), and J. W. Bailey (1946:263) present information which indicates that _Z. hudsonius_ stores food in its nests or burrows. Possibly these mice awaken at intervals from hibernation and eat.

"These rodents characteristically seize the material to be eaten with the front feet and devour it while reclining on their haunches. The following observation of a caged animal is typical of their feeding habits. The mouse selected a head of yellow foxtail, _Setaria glauca_ (Weig.) Stuntz, from several in the cage, separated it by gnawing through the supporting stem, seized it with the front feet, held it up to the mouth and began to gnaw at one end, stripping all parts from the rachis. The grass head was slowly rotated and shifted sideways until nothing remained but the rachis which was discarded. Actually the seeds were the only parts eaten ..." (Quimby, 1951:73). Sheldon (1934:294) remarks that _Z. hudsonius_ eats from a squatting position and holds the piece of food in the forepaws. The mouse seems to bite off a seed, and then, holding it in the forepaws, transfers it to the mouth.

According to Sheldon (_op. cit._:295) and Quimby (_loc. cit._), caged jumping mice drink water. When drinking, the mouths of the mice are in contact with the water, but neither observer determined whether the mice lapped or sucked the water. Sheldon (_loc. cit._) observed these mice passing stems of long grass through their mouths as though to squeeze out moisture, and thought that the mice obtain most of their required moisture from green plants.

_Reproduction._--The breeding season begins shortly after the jumping mice emerge from hibernation in the spring, and reproduction continues until a few weeks before they hibernate in the autumn. The extent of the breeding period probably varies geographically and possibly seasonally. For example, Quimby's (_op. cit._:70) information suggests that the 1947 period of parturition occurred between June 15 and August 30 in the area of Centerville, Minnesota. In Michigan, Blair (1940:246) found a peak of breeding activity in spring and another in late summer with little activity in the intervening midsummer. Brimley (1923:263) records a female in North Carolina, with eight embryos on June 13, 1895, and another with seven embryos on September 17, 1891, indicating a strong possibility of two litters per year there. Vernon Bailey (1927:118) records young born in May or June in North Dakota and thinks that there is time for only one litter per year. Petrides (1948:76) captured a female on September 22, 1944, at Athens, Georgia, that gave birth to six young on September 29. This late parturition date indicates a longer breeding season in the southeastern part of the range of _Z. hudsonius_.

The gestation period of nonlactating, caged _Z. hudsonius_, Quimby (1951:63) thinks, "is approximately 18 days ... [but] gestation is prolonged in lactating females."

Data from museum labels indicate that embryos in 62 pregnant females averaged 5.4 (2-8) per female. Quimby (1951:67) found the average number of embryos per female for 14 females taken in Minnesota, to be 5.3 and that litters of young found in nests averaged 5.8. Sheldon (1938:330) reports two litters of seven young each and one of four young for _Z. hudsonius_ in Vermont. Petrides (1948:76) records a litter of six young for _Z. hudsonius_ in Georgia. Brimley (1923:263) records one lot of seven and one lot of eight embryos for _Z. hudsonius_ in North Carolina. Vernon Bailey (1923:120) reports six embryos for a female of _Z. hudsonius_ taken in Washington, D. C. Ivor (1934:8) obtained a litter of five young _Z. hudsonius_ from Erindale, Peel County, Ontario. Hamilton (1935:195) records litters of two, four, and five young and embryo counts of four, two, four, and four for _Z. hudsonius_ in New York.

There seems to be two litters per year. According to Quimby (1951:69), "most adult females breed soon after emergence from hibernation and produce the first litters within a month. The remaining females do not breed immediately but produce the first litter," he says, "in the second month after emergence." Both early-breeding females and late-breeding females produce at least 2 litters per year. Those that breed early may have 3 litters.

The appearance and development of growing young of _Z. hudsonius_ in successive weeks is described by Quimby (1951:65). Newborn young are pink and hairless except for microscopic vibrissae. The eyes and external auditory meatus are closed, and the pinnae are folded. The toes are fleshy and clawless; the tail is short in relation to the length of the body. The average weight was .78 grams. The average measurements of three from different litters are: total length, 34 mm; tail, 9.2 mm; hind foot, 4.7 mm. The young are helpless but capable of emitting a high pitched squeaking sound which is audible for several feet.

In the first week of growth the vibrissae become visible to the naked eye, the body changes to flesh color, the dorsal parts become dark gray, the pinna unfolds and is black tipped, and the claws appear. The young now are able to crawl and make a suckling noise, but they are not yet able to support themselves on their legs.

In the second week of development, tawny yellow hair appears on the back and spreads onto the sides. Sparse hair of a lighter color appears on the belly, backs of the feet, and outer surfaces of the legs. Vibrissae are now prominent. The eyes are still closed, but a crack down the center of each is visible by the 13th day. Claws have grown, the longest measuring 1.5 mm. The incisors erupt on approximately the 13th day, those in the lower jaw appearing slightly before those in the upper jaw, and all are white. Activity is increased; nevertheless the young still crawl, make suckling notes, and squeak.

In the third week of development the mice are covered with hair; darker hair appears dorsally; and vibrissae continue rapid growth. The external auditory meatus begins to open on about the 19th day and young react to sound on the 20th. The incisors now are 1 mm long and the claws 1.5 mm long. Young are able to support themselves on their legs, walk, and make one inch hops.

In the fourth week the juvenal pelage is replaced by adult pelage. The eyes open between the 22nd and 25th days. The color of the incisors changes from white to yellowish-orange as in the adults. P^4, M^1, M^2, m1 and m2 have emerged from the maxillary and dentary bones; M^3 and m3 have not yet erupted. A mouse 33 days old had all teeth well developed. By the end of the 4th week the young, except for size, are adultlike and capable of independent existence.

The greatest increase in dimensions of the body is in the first four weeks. A slowing down of growth is simultaneous with weaning.

Other workers, Sheldon (1938:330), Petrides (1948:76), and Ivor (1934:8) also describe the appearance of the young.

Summer nesting sites are usually on the surface of the ground. Jumping mice characteristically construct a globular nest of grass but will utilize other vegetation if grasses are not available. Nests are usually concealed under rocks, logs, bushes, or grass and can be entered by a hole at one side.

Sheldon (1938:328) described a nest of _Z. hudsonius_ found on the ground near the edge of a small hay field. The nest was globular, not more than four inches in outside diameter and two inches in inside diameter; it was closely woven of fine, dry grass and bits of moss. Another nest found in the same field measured 11.5 inches in circumference at the base and six inches in circumference over the top. The inside width and length each was three inches, and the inside height was 3.5 inches. Vernon Bailey (1927:118) remarks that summer nests are placed on the surface of the ground well concealed under grass or other vegetation. He describes the nest as "neat little balls of fine grass with a tiny opening at one side and a soft lining in the central chamber." Cory (1912:249) reports that summer nests are concealed behind rocks or under bushes and thick grass. The nests are round and four or five inches in diameter with an entrance hole at one side. Goodwin (1935:148) examined a nest made entirely of straight, narrow leaves of grass. Ivor (1934:8) found one made of finely shredded jute sacking. Quimby (1951:80) describes several nests: one in the center of a rotten willow log was lined with small pieces of pulpy wood; another was in the rotted wood and debris, at ground level, inside a large, red oak (this globular nest composed of grasses, plant fibers, and rootlets measured six inches in diameter). Another nest was composed of a pile of wood pulp, leaves of oaks, and grasses; this nest was in a hollow root detached from a willow tree.

The mean home range of males, of _Z. hudsonius_ in Minnesota, according to Quimby (1951:86), was 2.70 plus or minus .50 acres; this was significantly larger than the mean home range of females, 1.57 plus or minus .27 acres. According to Quimby (_loc. cit._), the size and shape of the home range is influenced by the general features of the terrain, density and type of cover, and land use in the immediate area. Quimby (1951:94) remarked that the home range of the jumping mouse is relatively unstable and Blair (1940:247) stated that the home ranges of both sexes generally overlapped the ranges of other members of the same species and sex. The average size of the home range for _Z. hudsonius_ in Michigan was .89 plus or minus .11 acres for males and .92 plus or minus .11 acres for females.

=Zapus hudsonius acadicus= (Dawson)

_Meriones acadicus_ Dawson, Edinburgh New Philos. Jour., new ser.,
3:2, 1856.

_Meriones labradorius_, Dawson, Edinburgh New Philos. Jour., new
ser., 3:2, 1856.

_Jaculus hudsonius_, Baird, Rept. Expl. and Surv...., 8
(pt. 1):433, July 14, 1858 (part--the part from Nova Scotia,
Vermont, and New York).

_Zapus hudsonius_, Coues, Bull. U. S. Geol. and Geog. surv. of the
territories, 2nd ser., No. 5:260, 1877 (part--the part from Nova
Scotia, Vermont, and New York); Preble, N. Amer. Fauna, 15:17,
August 8, 1899 (part--the part from New Brunswick, Nova Scotia,
Maine, New Hampshire, Vermont, Massachusetts, and northeastern
New York).

_Zapus hudsonius canadensis_, Batchelder, Proc. New England Zool.
Club, 1:5, February 8, 1899 (part--the part from Keene Valley in
Essex County of New York, and Orivell in Vermont); Anderson, Ann.
Rept. Provancher Soc. Nat. Hist., Quebec, 1941:35-37, July 14, 1942
(part--the part from the tip of the Gaspé Peninsula in Quebec, New
Brunswick, Maine, New Hampshire, Vermont, and New York).

_Zapus hudsonius hardyi_, Batchelder, Proc. New England Zool. Club,
1:6, February 8, 1899, type from Mt. Desert Island, Hancock County,
Maine; Bole and Moulthrop, Sci. Publ. Cleveland Mus. Nat. Hist.,
5:165, September 11, 1947 (part--but excluding Pennsylvania and
Ohio).

_Zapus hudsonius acadicus_, Anderson, Ann. Rept. Provancher Soc.
Nat. Hist., Quebec, 1941:38, July 14, 1942.

_Type._--No type specimen designated. Subspecies characterized from specimens obtained in Nova Scotia.

_Range._--Gaspé Peninsula of Quebec, New Brunswick, Nova Scotia, Prince Edward Island, Maine, New Hampshire, Vermont, Massachusetts, northern Connecticut and northeastern New York. See fig. 47. Zonal range: Transition and Canadian.

_Description._--Size medium; back from near Ochraceous-Tawny to near Yellow-Ocher with heavy admixture of black-tipped hair, the dorsal band distinct against color of sides; sides lighter than back and from near Cinnamon-Buff to near Ochraceous-Buff lined with black-tipped hair; lateral line usually faintly marked but sometimes distinct and clear Warm-Buff; underparts white, sometimes suffused with color of sides; tail distinctly bicolored, brownish-black above and yellowish-white to grayish-white below; ears dark, edged with color of sides; feet grayish-white above; pterygoid fossae relatively narrow; zygomata relatively long and broad; auditory bullae relatively narrow, usually with depression on anterior surface; mastoid region relatively narrow; inferior arm of zygomatic process of maxillary relatively narrow.

_Comparisons._--From _Zapus hudsonius canadensis_, _Z. h. acadicus_ differs in: Size averaging larger; upper parts usually less brownish and more ochraceous, sides and flanks being more ochraceous and less yellowish; zygomata relatively longer; pterygoid fossae relatively narrower; auditory bullae relatively narrower and usually with depression on anterior surface.

From _Zapus hudsonius americanus_, _Z. h. acadicus_ differs as follows: Size larger; color darker on upper parts, flanks duller (less ochraceous); underparts white, much less frequently suffused with color of sides; ears dark, usually without flecks of ochraceous; general appearance of pelage not so brightly colored; zygomata longer; condylobasal length greater; mastoid region relatively broader; bullae larger, more inflated and usually with depression on anterior surface; maxillary tooth-row relatively longer.

For comparison with _Zapus hudsonius ladas_ see account of that subspecies.

_Remarks._--Specimens from various localities in Nova Scotia, Prince Edward Island and New Brunswick are essentially similar. Anderson (1942:38) revived the name _Z. h. acadicus_ for jumping mice from these areas, correctly considering them to be distinct from _Z. h. canadensis_, the geographic race immediately to the west.

In the size and shape of the auditory bullae, length of the zygomata, breadth of the pterygoid fossae, and general color of the pelage the populations from Nova Scotia and New Brunswick are essentially indistinguishable from material of _Zapus hudsonius hardyi_ from Maine. Thus, _Z. h. hardyi_ must fall as a synonym of the earlier proposed name _Z. h. acadicus_.

Bole and Moulthrop (1942:165) applied the name _Z. h. hardyi_ (= _acadicus_) to the mice inhabiting a large area from coastal Maine and central New Hampshire through southern New England, New York, northwestern Pennsylvania, and northeastern Ohio. I agree with Bole and Moulthrop (_loc. cit._) that the population of _Zapus hudsonius_ from Maine, New Hampshire, west-central and northern New England are different from neighboring subspecies and are referable to _Z. h. acadicus_, but find that material from extreme southern Massachusetts, Connecticut, southern New York, northwestern Pennsylvania, and northeastern Ohio is best referred to _Zapus hudsonius americanus_ (see account of that subspecies).

Intergradation between _Z. h. americanus_ and _Z. h. acadicus_ is indicated by specimens from Berlin, Rensselaer County, New York. In color of ears, length of zygomata, and size and shape of the incisive foramina these specimens are more nearly like _Z. h. americanus_ but in size and shape of the auditory bullae, breadth of the mastoid region, and general appearance of the pelage they are more nearly like _Z. h. acadicus_ and are here referred to _acadicus_. Specimens from Glenville, Schenectady County, New York, are intermediate in cranial characters between _Z. h. americanus_ and _Z. h. acadicus_ but in color are best referred to the latter. Specimens from 1 mi. S Ayer, Worchester County, Massachusetts, are like _Z. h. americanus_ in their short zygomata, narrow mastoid region and suffusion of the underparts; nevertheless, in the shape of the auditory bullae, breadth of the pterygoid fossae, and greater condylobasal length the specimens are more nearly like _Z. h. acadicus_ which they are here considered to be. Animals from Essex and Wilmington, Essex County, Massachusetts, are like _Z. h. americanus_ in external size and in the size and shape of the auditory bullae; but they are more nearly like _Z. h. acadicus_ in most cranial characters and in the general color of the pelage and are here assigned to _Z. h. acadicus_.

Specimens from Keene Valley, Essex County, New York, considered by Batchelder (1899:4) to be _Z. h. canadensis_, are in color, length of the zygomata, and size and shape of the auditory bullae more nearly like _Z. h. acadicus_ to which subspecies they are here assigned. A specimen from Orwell, Addison County, Vermont, that Batchelder (_op. cit._:5) referred to _Z. h. canadensis_ is more nearly like _Z. h. acadicus_ in the shape of the auditory bullae, length of the zygomata, and color of the pelage, and is here referred to _Z. h. acadicus_. Specimens from western New Brunswick, referred to _Z. h. canadensis_ by Anderson (1942:37), are more nearly like _Z. h. acadicus_. Specimens from Ste. Anne des Monts, Gaspé Peninsula, Quebec, are intermediate between _Z. h. canadensis_ and _Z. h. acadicus_ in color and size and also in the shape of the auditory bullae but are best referred to _Z. h. acadicus_.