Range.—Pacific coastal region from Requa, Del Norte County, California, north in Oregon west of the Cascades, and in Washington including the Cascades; to southwestern British Columbia.
Description.—Size large; back from near Ochraceous-Buff to near Tawny with admixture of black hair forming broad dorsal band; sides lighter than back from near Ochraceous-Buff to near Tawny; lateral line usually distinct; belly white, sometimes with faint suffusion of ochraceous on lower throat and upper chest; tail bicolored, brown above, white to yellowish-white below; ears dark, sometimes flecked with color of sides, edged with ochraceous; feet grayish-white above; palatal bridge relatively short; incisive foramina relatively long; condylobasal region long; zygomatic width great; braincase relatively broad; distance from incisors to postpalatal notch relatively great.
Comparisons.—For comparisons with Zapus trinotatus montanus and Zapus trinotatus eureka see accounts of those subspecies.
Remarks.—This subspecies retains most of its diagnostic characters throughout nearly all parts of its geographic range. Intergradation occurs between Z. t. eureka and Z. t. trinotatus in extreme southwestern Oregon and northwestern California (see account of Z. t. eureka). Intergrades between Z. t. montanus and Z. t. trinotatus have been commented on in the account of Z. t. montanus. Specimens from Eugene, Oregon, according to Bailey (1936:232), show affinity to Z. t. montanus but are considered by him to be Z. t. trinotatus.
Specimens examined.—Total, 238, distributed as follows:
British Columbia: Alta Lake, on Pac. Gt. Eastern Ry., 2600 ft., 5 (MVZ); Okanagan, 1 (FM); Vedder Crossing, 4 (1 MVZ, 3 PM); Chilliwack Valley, 2 (NMC); 18 mi. S Chilliwack, 1 (MVZ); Cultus Lake, 2 (NMC); Lihumption Park, 4500-4800 ft., 12 (NMC); Seymour Mtn., 4000 ft., 8 (1 MVZ, 7 PM); Cariboo, 2 (FM); Sumas, 8 (1 MVZ, 7 FM); Huntingdon, 40 (NMC); Parnassus Creek, Black Tusk Meadow, 5200 ft., 1 (PM); Howe Sound, Brackendale, 2 (NMC); Stanley Park, Vancouver, 1 (PM); Allison Pass, Manning Park, 1 (PM); Manning Park, 2 (PM).
California: Del Norte Co.: Crescent City, 11 (6 FM, 5 USBS); Requa, 4 (FM).
Oregon: Benton County: 3 mi. N Corvallis, 2. Clatsop County: Old Fort Clatsop, 100 ft., 11 (MVZ); 71/2 mi. S Cannon Beach, 50 ft., 1 (MVZ). Columbia County: 7 mi. SE Rainier, 100 ft., 11 (MVZ). Curry County: Gold Beach, 3 (FM). Douglas County: Gardiner, 7 (5 MVZ, 2 FM). Lane County: Sutton Lake, 6 mi. N Florence, 1 (MVZ). Lincoln County: Delake, 3 (2 MVZ); Newport, 2 (MVZ). Multnomah County: Portland, Council Crest, 950 ft., 1 [394] (MVZ). Tillamook Co.: Tillamook, 1 (MVZ); 9 mi. S Tillamook, 1 (MVZ); Netarts, 3 (SDM); Blaine, 3 (MVZ). Washington County: 181/2 mi. NW Portland, 1300 ft., 5 (MVZ).
Washington: Clallam County: Deer Lake, 3800 ft., 3. Clarke County: 31/2 mi. E and 11/2 N Amboy, 3500 ft., 3 (MVZ); 11/2 mi. ENE Amboy, 3500 ft., 13 (MVZ); 31/2 mi. E and 5 mi. N Yacolt, 500 ft., 1 (MVZ); 11/2 mi. W Yacolt, 800 ft., 11 (MVZ). Cowlitz County: 6 mi. NE Kelso, 4 (MVZ); 4 mi. E mouth Kalama River, 5 (MVZ). King County: Lakeridge Tract, S end Forest Ave., Lake Washington, 2 (MVZ); Seattle 2 (MVZ); Snoqualmie Pass, 5 (MVZ). Mason County: Potlatch, 2 (MVZ). Pacific County: 11/2 mi. N Chinook, 10 ft., 1 (MVZ); 31/2 mi. SE Chinook, 10 ft., 5 (MVZ). Pierce Co.: 5 mi. E Tacoma, 4 (MVZ); Puyallup, 3 (1 MVZ, 2 FM); Mt. Rainier, 1 (MVZ); 3 mi. E Ashford, 1 (LMH). Skamania County: Ice Caves, 2800 ft., 5 mi. WSW Guler, 1 (MVZ). Thurston County: Boston Harbor, 5 (CAS). Wahkiakum County: 4 mi. E Skamokawa, 5 (MVZ). Whatcom County: Baker Lake, 2 (MVZ).
Marginal records.—British Columbia: Okanagan; Manning Park. Washington: Baker Lake; Snoqualmie Pass; Mt. Rainier; Ice Caves, 2800 ft., 5 mi. WSW Gulch. Oregon: Portland, Council Crest, 950 ft. California: Requa; Crescent City. Oregon: Gold Beach; Gardiner; Sutton Lake, 6 mi. N Florence; Newport; Netarts; Old Fort Clatsop, 100 ft. Washington: 31/2 mi. SE Chinook, 10 ft.; Deer Lake, 3800 ft. British Columbia: Stanley Park, Vancouver; Alta Lake, 2600 ft.