Microtus townsendii (Bachman, 1839) . J. Acad. Nat. Sci. Philadelphia, 8:60.

TYPE LOCALITY: USA, Oregon, Multnomah Co., Wappatoo (Sauvie) Island, lower Columbia River near mouth of Willamette River (as located by Bailey, 1900:46) .

DISTRIBUTION: Pacific northwest, from extreme SW British Columbia, Canada, to NW California, USA, including Vancouver and neighboring islands.

SYNONYMS: cowani, cummingi, laingi, occidentalis, pugeti, tetramerus .

COMMENTS: Subgenus Mynomes, pennsylvanicus species group sensu Zagorodnyuk (1990) . Broadly allied with M. pennsylvanicus and M. nwntanus (Anderson, 1959; Hooper and Hart, 1962; Modi, 1987), though precise cladistic picture unresolved. See Comely and Verts (1988, Mammalian Species, 325).