_Racial characters._--Similar to _bangsi_ and _columbiensis_ but with larger feet and grayer color. _Measurements._--Howell (1918: 49) gives the average of 10 specimens as: total length 342; length of tail 153; hind foot 41.5. _Distribution._--The Pend Oreille Mountains of extreme northeastern Washington, north (from records of Taylor and Shaw, 1929: 18-19, as revised) to Sullivan Lake and south to Loon Lake. =Glaucomys sabrinus fuliginosus= (Rhoads) _Sciuropterus alpinus fuliginosus_ Rhoads, Proc. Acad. Nat. Sci. Philadelphia, p. 321, June, 1897. _Glaucomys sabrinus fuliginosus_ Howell, N. Amer. Fauna, 44:47, June 13, 1918. _Type._--Obtained at Martin Station, Kittitas County, Washington, by Allan Rupert in March, 1893; type in Philadelphia Academy of Natural Sciences. _Racial characters._--Similar to _columbiensis_ but underparts darker and tail paler. Larger and paler than _oregonensis_. _Measurements._--Three females from the Cascades average: total length 327; length of tail 145; hind foot 40.7; ear 25. _Distribution._--The Cascade Mountains, according to Taylor and Shaw (1929: 18), as revised here, east to Entiat River and south to Carson. =Perognathus parvus= (Peale) Great Basin pocket mouse _Description._--Great Basin pocket mice are slightly larger than house mice. The ears are tiny and round; the tail is relatively long, slightly longer than the head and body; the forefeet are small but the hind feet are large and powerful, more than one-fourth as long as the head and body. They have relatively large, fur-lined, external cheek pouches. The color of the upper parts varies with the subspecies from blackish olive-gray to buffy olive-gray; a line of clear buff or buffy-olive extends along the lower part of side, separating the darker color of the upper parts from the white underparts; the tail is short-haired, blackish above, olive beneath. Pocket mice of the genus _Perognathus_ range from Mexico northward to British Columbia. Only one species, _parvus_, occurs in Washington where it is represented by three subspecies. Pocket mice are most common in the Upper Sonoran Life-zone in sandy areas dotted with desert shrubs. They are found occasionally in dry, grassy places in the Arid Transition Life-zone. They may be locally abundant in rocky areas and are often trapped high on talus slides, many yards from the nearest soil. Gray (1943: 191-193) estimates their numbers on the sagebrush areas of the Yakima Valley at 32 per acre. They are completely nocturnal. Their ordinary movements are rather slow and specimens studied by the aid of a searchlight usually crept quietly into the protection of the nearest desert shrub. The trail of a pocket mouse in soft sand may be recognized by the distinctive mark left by the dragging tail.