Microtus californicus Pt. Reyes Station, salt marsh, Marin Co., Calif. Mar. 26, 1937 1 taken in 35 traps set in Salicornia, sedge? and arrowgrass (Triglochin) in runways not over 100 ft. from chaparral covered hillside. Substrate very wet - due to recent extensive & heavy rains. SW side Tomales Bay, opposite Pt. Reyes Station, Mar. 26, 1937 1 taken in 25 traps set in Salicornia and Triglochin (?) in runways (some) not over 100 ft. from wooded hillside. Pt. Reyes rock, 2 mi. NW Inverness, Marin Co., Calif. Mar. 27, 1937 1 taken in 50 traps set in wet meadow in sedge ground under sword fern and arrowgrass - some small grass between slumps. Grand Canyon, 2 mi. N Pt. Reyes Station, Marin Co., Calif. Mar. 28, 1937 3 taken in 45 traps set on SE facing slope under poison oak, Baccharis, Calif. Bay - some grass between brush thickets and trees. Bivolve, 2 mi. N Pt. Reyes Station, Marin Co., Calif. Mar. 28, 1937 2 taken in runways (35 traps - but many sprung and bait gone) in Salicornia about 15 ft. from a chaparral- covered hillside.