_Range._--Altitudinally from sea level up to at least 4800 feet (Mount Baker) in the Transition Life-zone of the humid, coastal region of Oregon, Washington and extreme southwestern British Columbia. See figure 29 on page 221. _Characters for ready recognition._--Differs from _M. f. nevadensis_ in tone 4 of Brownish Drab, pl. 302, rather than tones 1-3, of Raw Umber, pl. 301, of Oberthür and Dauthenay of upper parts, in near (14 _a´_ to 16 _c´_) Ochraceous-Buff rather than Buff-Yellow to Straw Yellow of underparts, in that least width of color of underparts amounts to less than 37 per cent of greatest width of color of upper parts, in absence of color of underparts on ventral side of tail and on hind leg distal to knee, and in greater depth of skull through frontal region; from _M. f. washingtoni_ in darker color of upper parts and underparts, latter near (14 _a_´ to 16 _c_´) Ochraceous-Buff rather than ranging from Buff-Yellow to Naples Yellow, in deeper skull in both sexes (see measurements), in males a shorter preorbital region, broader skull with longer bullae and in females a larger skull with interorbital breadth averaging more than 24 per cent of basilar length; from _M. f. oregonensis_ in frontonasal white patch absent, color above darker (tone 4 of Brownish Drab, pl. 302, rather than tone 2 to 3 of Raw Umber, pl. 301 of Oberthür and Dauthenay), light-colored underparts narrower and not extended distally beyond knee, in females tooth-row shorter, amounting to less than 38 per cent of basilar length. _Description._--_Size._--Male: Eight adult topotypes yield average and extreme measurements as follows: Total length, 426 (392-445); length of tail, 160 (148-170); length of hind foot, 47 (42-53). Tail averages 60 per cent as long as head and body. Length of hind foot averages more than basal length. Female: Five adults from Tillamook and Blaine, Oregon, yield average and extreme measurements as follows: Total length, 347 (320-370); length of tail, 125 (114-131); length of hind foot, 38 (35-44). Tail averages 56 per cent as long as head and body. Length of hind foot less than basal length. The average differences in the external measurements are: Total length, 79; length of tail, 35; length of hind foot, 9. _Externals._--Longest facial vibrissae black, brown or white (often all three colors in same specimen) and extending beyond ear; carpal vibrissae same color as underparts and extending to or beyond apical pad of fifth digit; hairiness of foot-soles (in summer pledge) slightly less than shown in figure 19.