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.