Sorex haydeni Baird, 1857 . Mammalia, in Repts. U.S. Expl. Surv., 8(1):29.

TYPE LOCALITY: USA, "Fort Union, Nebraska " (later Fort Buford, now Mondak, Montana, near Buford, Williams Co., North Dakota) .

DISTRIBUTION: SE Alberta, S Saskatchewan, SW Manitoba (Canada); NW Montana southeast to Kansas, east to W and S Minnesota (USA).

COMMENTS: Subgenus Otisorex . Formerly included in but now separated from cinereus by van Zyll de Jong (1980) and Junge and Hoffmann (1981); both species are closely related (George, 1988). S. haydeni occurs in grassy habitats while S. cinereus prefers forest and woodland (van Zyll de Jong, 1980).