Specimens from various localities in southeastern Ohio, all within the range ascribed by Bole and Moulthrop (_op. cit._:169) to _Zapus hudsonius rafinesquei_, are indistinguishable from specimens of _Z. h. americanus_ from eastern Tennessee, West Virginia, North Carolina, and Maryland. _Zapus hudsonius rafinesquei_ (at least that part from southeastern Ohio) is indistinguishable from _Z. h. americanus_ and therefore is synonymized under _Z. h. americanus_.
Specimens from Lagrange County, Indiana, show intergradation between _Zapus hudsonius intermedius_ and _Z. h. americanus_ in the color of the pelage but are more nearly like _Z. h. americanus_ to which they are here referred. One from Porter County, Indiana, is more nearly like _Z. h. intermedius_ in size and shape of the bullae and in breadth of the pterygoid fossae but in color and degree of lateral bowing of the zygomata is better placed with _Z. h. americanus_.
_Z. h. americanus_ is a wide ranging subspecies. Animals at the northern periphery of the range (lower peninsula of Michigan to the west and southeastern Massachusetts to the east) are largest and darkest; to the southward there is a progressive reduction in size and a change to a lighter, brighter color. Animals from Maryland, Virginia, and North Carolina are more nearly average representatives of the subspecies than are those from the region of the type locality.
A jumping mouse allegedly of this subspecies has been recorded by Coleman (1941:91) from Caesars Head, 300 ft., South Carolina. This specimen and one from Athens, Georgia, provide the southeasternmost record-stations of occurrence for the species _Z. hudsonius_.
_Specimens examined._--Total, 318, distributed as follows:
CONNECTICUT: _Hartford County_: _Windsor_, 1 (USBS); _East Hartford_, 2 (MCZ). _Litchfield County_: Sharon, 3 (AMNH); _Macedonia Park_, 2 (AMNH). _Middlesex County_: _Clinton_, 1 (AMNH). _Windham County_: South Woodstock, 10 (AMNH); _Pomfret, near Hampton line_, 1.
INDIANA: _Lagrange Co._: no exact locality, 2 (UM). _Porter Co._: Mineral Springs, 1 (FM); _no exact locality_, 1 (FM).
MARYLAND: _Anne Arundel County_: _Patuxent Research Refuge_, 1 (USBS). _Charles County_: _no exact locality_, 1 (USBS). _Garrett Co._: Finzel, 6 mi. N Frostburg, 1 (USBS). _Montgomery County_: _Sandy Springs_, 2 (USBS); _Kensington_, 1 (USNM); _Cabin John Bridge_, 2 (1 USBS; 1 USNM). _Prince Georges County_: _Laurel_, 8 (USNM); _Branchville_, 1 (USBS); _College Park_, 1. _Worchester County_: Assateague, 5 mi. S Ocean City, 1 (USBS).