Crickson. 1933 1934 Peromyscus eremicus Palm Springs, Riverside Co., Calif. Dec. 28, 1933 Caught two in sandy wash at base of mountains. one still alive, escaped; ran to bushes 15 ft. away; saw line, but lost before it was within reach. West base of Castle Dome, Yuma Co., Ariz. Jan. 10, 1934 no. 172 taken at top of rocky hill standing apart but near base of main range; trap between rocks. West base of Castle Dome. Jan. 11, 1934 a σ, no. 177, taken at base of rocky hill at point where wash comes to base; under sheltering ledge of rock, hole coming out from between and under rocks. a φ, no. 176, taken at top of same hill as above, at opposite end, about 150 feet distant; mouse evidently caught as ran along trail at base of 4-5 inch rock wall to hole which was under shelter of jutting rock; next to traps of line spring; other 12 on hill untouched; no embryos. Tinajas Altas, Yuma Co., Ariz. Jan. 13, 1934 5 specimens taken, from wash at base of steep rock strewn slope to an elevation of 1300 ft., as high as traps set. one at edge of sandy wash - 6 ft wide, which carries away overflow of tanks, at time of rains; another where mesa comes to base of rocks and others on rocks of shallow draw or gully on NE facing slope. at south of tanks. Tinajas Altas Jan. 16, 1934 a male taken at elevation of 1350 ft. at lower end