Smiley 1956 Microdipodops sp. 4 mi. NW Flanigan, 4200 ft., Washoe Co., Nev. July 4 16 specimens caught in area of abruptly rolling sand dunes. Sand fine, wind-blown, dirty white. Sarcobatus on abundant plant. Dunes ranged from three to six feet in height. All burrows seen of proper size for this mammal were plugged with sand; some of these were removed several feet from the base of any bush, therefore, burrows remained burrows due to the dampness of sand below the surface. This the most abundant animal caught in 59 traps set. July 5 N side Sand Pass, 3950 ft., Washoe Co., Nev. Number of specimens taken not recorded. Area of wind-blown sand and silt, dirty gray in color, without conspicuous dune structure; drifted around base of unidentified Sagebrush-like plants where there were open burrows of Dipodomys and sand-plugged burrows of this species. A conspicuous plant Porosela a sturdy-stemmed legume with tiny purple flowers. July 12 3 mi. E 10 mi. N Gerlach, 4000 ft., Washoe Co., Nev. In area of sand-silt with slight dune-like structure; Crusted over by rain; one specimen caught. Deserted burrows indicated that many rodents had probably been drowned out. Sarcobatus association,