Synaptomys cooperi Baird, 1858 . Mammalia in Repts. U.S. Expl. Surv., 8(1):558.

TYPE LOCALITY: USA, New Hampshire, Carroll Co., Jackson (as fixed by Bole and Moulthrop, 1942:146) .

DISTRIBUTION: Midwestern and E USA through SE Canada, including Nova Scotia and Cape Breton Island; as far south as W North Carolina and NE Arkansas; outlying populations in SW Kansas and W Nebraska.

SYNONYMS: fatuus, gossii, helaletes, jesseni, kentucki, paludis, relictus, saturatus, stonei .

COMMENTS: Subgenus Synaptomys . Geographic diversification evaluated by Wetzel (1955). See Linzey (1983, Mammalian Species, 210).