_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. GEORGIA: _Clarke Co._: Athens, 1 (USBS). 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). MASSACHUSETTS: _Barnstable County_: _West Falmouth_, 1 (USBS). _Bristol County_: _Raynham_, 1 (Clev. MNH). _Dukes County_: _Martha's Vineyard_, 1 (USBS); _West Chop, Martha's Vineyard_, 1 (Clev. MNH). _Nantucket County_: _Nantucket Island_, 1 (USNM). _Plymouth County_: Middleboro, 1 (USNM); _Plymouth_, 1 (UM); _Marshfield_, 6 (USBS); _Wareham_, 3 (1 Clev. MNH; 2 UM).