Measurements.—Twenty-one male and 9 female topotypes average, respectively: total length 173, 168; length of tail 91, 89; hind foot 23.9, 22.8; ear 5, 5.
Distribution.—The vicinity of the type locality and the part of the Columbian Plateau north of the Snake and east of the Columbia rivers.
Remarks.—This race is separated from parvus by river barriers and the two do not intergrade. It differs significantly from lordi only in the wider mastoid region. No barrier separates the range of lordi from that of parvus, and the two races intergrade over a wide area (north to Moses Lake, east to Washtucna). The race columbianus must have originated in situ from lordi. The habitat of columbianus seems not to differ from that of parvus or lordi.
Dipodomys ordii columbianus ([Merriam])
Ord kangaroo rat
Perodipus ordi columbianus [Merriam], Proc. Biol. Soc. Washington, 9:115, June 21, 1894.
Dipodomys ordii columbianus [Grinnell], Jour. Mamm., 2:96, May 2, 1921.
Type.—Obtained at Umatilla, Umatilla County, Oregon, by C. P. Streator on October 18, 1890; type in United States National Museum.
Measurements.—Fourteen males and 9 females from Walla Walla County average, respectively: total length 261.5, 248.4; length of tail 137.2, 139.1; hind foot 40.6, 40.8; ear 13.1, 13.0; weight 52.1, 49.0 grams.
Distribution.—Western Walla Walla County from the Oregon boundary north to the Snake River and on Blalock Island in the Columbia River, Benton County.