Thomomys bulbivorus (Richardson, 1829) . Quadrupeds, in Fauna Boreali- Americana, 1:206.

TYPE LOCALITY: USA, banks of Columbia River (probably Portland, Multnomah Co., Oregon; see Bailey, 1915) .

DISTRIBUTION: Willamette Valley (NW Oregon, USA).

COMMENTS: Subgenus Megascapheus . Revised by Bailey (1915).