Part 23

Type.--Male, adult, skin and skull, No. 73584, U. S. Nat. Mus., Biol. Surv. Coll.; Yakutat Bay, Alaska; obtained on July 5, 1895, by Clark P. Streator, original No. 4660.

Range.--Alaska Peninsula, coastal section of mainland of southern and southeastern Alaska including Revillagigedo Island; also southwestern Yukon. See fig. 47. Zonal range: Canadian and Hudsonian.

Description.--Size large; back from near Ochraceous-Tawny to near Dresden Brown, sometimes darkened with black tipped hair usually with darker mid-dorsal area forming a band; sides lighter than back and from near Ochraceous-Tawny to near Clay Color; lateral line usually distinct, of clear Ochraceous-Buff; belly white, frequently with a slight suffusion of Ochraceous-Buff; tail bicolored, brownish to brownish-black above, white to yellowish-white below; ears dark, edged and flecked on the inner surface with color of sides; feet grayish-white above; auditory bullae broad and moderately inflated; pterygoid fossae relatively broad; incisive foramina relatively long, zygomata relatively long and broadly bowed; mastoid region relatively broad; distance from incisors to postpalatal notch relatively great; occipitonasal length relatively great.

Comparisons.--From Zapus hudsonius tenellus, Z. h. alascensis differs as follows: Size larger; upper parts darker, less ochraceous; sides duller, less ochraceous more tawny; incisive foramina averaging longer; mastoid region broader; occipitonasal length greater; zygomata wider-spreading and longer; condylobasal length averaging greater; auditory bullae less broadly rounded; and distance from incisors to postpalatal notch averaging greater.

For comparison with Zapus hudsonius hudsonius see account of that subspecies.

Remarks.--Zapus hudsonius alascensis is a fairly well marked subspecies retaining most of its characters throughout its range. Variation is noted in specimens from the southwest end of Dezadeash Lake, 2400 ft., Yukon Territory, and seems to be the result of intergradation between Zapus hudsonius hudsonius and Z. h. alascensis. These animals are like Z. h. hudsonius in the shape of the auditory bullae but are otherwise more nearly like Z. h. alascensis to which they are here assigned. Alaskan specimens from 7 mi. SSE Haines, and from a point 9 mi. W and 4 mi. N Haines average slightly larger than Z. h. alascensis in most measurements taken; however, in coloration they more nearly agree with Z. h. alascensis than with Z. h. hudsonius or Z. h. tenellus the geographic ranges of which adjoin that of Z. h. alascensis.

Specimens examined.--Total, 56, distributed as follows:

ALASKA: Cook Inlet, Tyonek, 1 (USBS); head Chalitna River, 2 (USBS); Lake Clark, 4 (USBS); east side Chilkat River, 100 ft., 9 mi. W and 4 mi. N Haines, 8; Yakutat, 3 (USBS); Lake Iliamma, 1 (USBS); Lake Aleknagik, 1 (USBS); Kokwok, 1 (USBS); Nushagak River, 3 (USBS); Chilkat Peninsula, 10 ft., 7 mi. SSE Haines, 18; Nushagak, 3 (USBS); Chignik Bay, 1 (USBS); Portage Cove, Revillagigedo, 1 (MVZ); Izembek Bay, 1 (USBS); Frosty Peak, 1 (USBS).

BRITISH COLUMBIA: west end Kelsall Lake, 2900 ft., 1; Stonehouse Creek, 5-1/2 mi. W junction Stonehouse Creek and Kelsall River, 4.

YUKON: SW end Dezadeash Lake, 2400 ft., 2.

Marginal records.--Alaska: Lake Aleknagik; head Chalitna River. Yukon: SW end Dezadeash Lake, 2400 ft. Alaska: E side Chilkat River, 100 ft., 9 mi. W and 4 mi. N Haines; Portage Cove, Revillagigedo Island; Yakutat; Cook Inlet, Tyonek; Chignik Bay; Frosty Peak.

=Zapus hudsonius americanus= (Barton)

Dipus americanus Barton, Trans. Amer. Philos. Soc., 4:115, 1799.

Jaculus americanus Wagler, Nat. Syst. Amphibien, 23, 1830.

Meriones microcephalus Harlan, Proc. Zool. Soc. London, p. 1, 1839, based on two specimens from "the farm of Mr. Beck, in Philadelphia County, a few miles northeast of the city [= Philadelphia, Pennsylvania]."

Jaculus hudsonius, Baird, Repts. Expl. and Surv. 111, 8 (pt. 1): 433, July 14, 1858 (part--the part from Massachusetts, Connecticut, New York, New Jersey, and Pennsylvania).

Zapus hudsonius, Coues, Bull. U. S. Geol. and Geog. Surv. of the territories, 2nd ser. No. 5:260, 1877 (part--the part from Massachusetts, Connecticut, New York, and Pennsylvania); Preble, N. Amer. Fauna, 15:17, August 8, 1899 (part--the part from Peterboro and Waterville, New York, southeastern Massachusetts, Connecticut, New Jersey, Pennsylvania, West Virginia, Maryland, North Carolina, and Ohio).

Zapus hudsonius americanus, Batchelder, Proc. New England Zool. Club, 1:6, February 8, 1899; Preble, N. Amer. Fauna, 15:19, August 8, 1899.

Zapus hudsonius hardyi, Bole and Moulthrop, Sci. Publ. Cleveland Mus. Nat. Hist., 5:165, September 11, 1942 (part--the part from New York, Ohio, and Pennsylvania).

Zapus hudsonius brevipes Bole and Moulthrop, Sci. Publ. Cleveland Mus. Nat. Hist., 5:168, September 11, 1942, type from Bettsville, Seneca County, Ohio.

Zapus hudsonius rafinesquei Bole and Moulthrop, Sci. Publ. Cleveland Mus. Nat. Hist., 5:169, September 11, 1942 (part--the part from southeastern Ohio), type from Cat Run, extreme southeastern Belmont County, Ohio.

Type.--No type specimen designated. Dipus americanus was characterized from jumping mice obtained by Barton near the Schuylkill River, a few miles from Philadelphia, Pennsylvania.

Range.--Southeastern United States and lower peninsula of Michigan; east of central Indiana; from central New York and Massachusetts southward to northern Georgia. See fig. 47. Zonal range: Austroriparian (Lower Austral), Carolinian (Upper Austral), Alleghanian (Transition), and Canadian.

Description.--Size small; back from near Light Ochraceous-Buff to near Ochraceous-Buff with admixture of black-tipped hair forming distinct dorsal band; sides bright, lighter than back from near Light Ochraceous-Buff to near Ochraceous-Buff; lateral line usually distinct and of color of sides; underparts white, sometimes with slight suffusion of color of sides; tail bicolored, brown to brownish-black above, yellowish-white to grayish-white below; ears narrowly edged and heavily flecked with color of sides; feet white to grayish-white above; skull short; braincase relatively narrow; incisive foramina relatively broad; skull relatively narrow across zygomata; interorbital region relatively broad; distance from incisors to postpalatal notch relatively short; auditory bullae relatively small.

Comparisons.--Compared with Zapus hudsonius canadensis, Z. h. americanus differs as follows: Smaller; paler (in a sense brighter because more ochraceous and less tawny); skull smaller; auditory bullae narrower, less inflated; incisive foramina relatively more bowed; condylobasal length averaging less.

From Zapus hudsonius intermedius, Z. h. americanus differs as follows: Smaller; color brighter, more ochraceous, less yellow; braincase relatively narrower; auditory bullae usually smaller; incisive foramina broader; inferior ramus of zygomatic process of maxillary usually with median projection; interorbital region averaging broader.

For comparison with Zapus hudsonius acadicus see account of that subspecies.

Remarks.--Intergradation with Zapus hudsonius acadicus occurs in southeastern New York as indicated by a series of 25 specimens from Peterboro. They resemble Z. h. acadicus in width of the mastoid region and relatively longer tooth-row, but in the size and shape of the auditory bullae, width of the pterygoid fossae, and lighter, brighter, color of the sides they are more nearly like Z. h. americanus to which they are here referred.