Lee Arnold 1937 Peroimathus longimembrio May 27 Warm Spring, Lassen Co., Calif. One specimen caught 1/4 mile east of spring. Captured in some type of country Microdipodops was found in. This is the first recorded on this trip. Habitat - senny, loose loam with salt bush about 10 ft. apart (Oth). May 30 4 mi. NW Pahrum Pk., Washoe Co., Nevada 6 caught - 3 B + 3 F. In sandy soil of east edge of smoke creek desert. The type of habitat was that in which I expected to get Microdipodops. The area was characterized by wind blown sand. The night that the traps were set was very windy but it had little (seemingly) effect on the animal life (1 F - 6 emb. (1 F - 5 emb.) Fox Canyon, 4800 ft., 4 mi S Pahrum Pk., Washoe Co., Nevada May 31 3 caught - 2 B + 1 F with 6 embryos in gravel soil on side of canyon NW of camp. In each of the spots where these were caught, however, fine silty dust was near at hand. This area was not nearly so dusty as those in which the previous mice were captured. June 4 near Smith Creek Cave, 5800 ft., Mt Moriah, White Pine Co., Nevada. 3 caught - all F's. These were caught in silty-gravel east of camp. The bushes where these were captured consisted of