Clethrionomys occidentalis nivarius (Bailey).
1897. Evotomys nivarius Bailey, Proc. Biol. Soc. Washington, 11:136, May 13, type from northwest slope of Mount Ellinor, 4000 ft., Olympic Mts., Mason County, Washington.
Clethrionomys occidentalis obscurus (Merriam).
1897. Evotomys obscurus Merriam, Proc. Biol. Soc. Washington, 11:72, April 21, type from Prospect, 2600 ft., upper Rogue River Valley, Jackson County, Oregon.
1933. Clethrionomys mazama obscurus, Grinnell, Univ. California Publ. Zool., 40:185, September 26.
1936. Clethrionomys californicus obscurus, Bailey, N. Amer. Fauna, 55:192, August 29.
Clethrionomys gapperi pallescens, new name
1940. Clethrionomys gapperi rufescens R. W. Smith, Amer. Midland Nat., 24:233, July, type from Wolfville, Kings County, Nova Scotia (nec Arvicola rufescens de Selys Longchamps, 1836, from Longchamps-sur-Ger, Belgium).
The name rufescens, as applied by R. W. Smith (Amer. Midland Nat., 24:233, July, 1940) to the red-backed mouse of Nova Scotia, seems to be unavailable under the rules of the International Code of Zoological Nomenclature, since it is a homonym of Arvicola rufescens de Selys Longchamps, 1836, which in turn is a synonym of Clethrionomys glareolus glareolus Schreber, 1780 (Ellerman and Morrison-Scott, Checklist of Palaearctic and Indian Mammals, 1758 to 1946, p. 663, November 19, 1951).
Clethrionomys gapperi phaeus (Swarth)