Hooper Peromyscus maniculatus 2 1/2 mi. S Antioch, 250 ft., Contra Costa Co., Calif. Mar. 7, 1937 Caught 1 specimen in 20 mouse traps set at a average distance of 3 paces apart, on a grassy hilltop ("shaped"), at the mouths of old (but seemingly used ground against burrows). Traps baited with oatmeal. Zone Upper Sonoma. 1 mi. S Antioch, 100 ft., Contra Costa Co. Mar. 7, 1937 Caught 21 P.M. out of 48 traps set in wheat stubble and, along a stubble-lined stream running through the field and along an east-facing slope or still in stubble. Caught 2 animals in 1 trap. Traps baited with oatmeal. SW side Tomales Bay, opposite P.A. Reys Station, Marin Co., Calif. Mar. 26, 1937 5 (3 juv.) taken in 25 traps set in Salicornia and Triglochin in runways not over 100 ft. from wooded (Transition-lunul) hillside. These caught in pure Salicornia. Inverness, 100 ft., Marin Co., Calif. Mar. 27, 1937 4 taken in 28 traps set in moist wood-under box and alder trees, ferns on NW facing slope; soil very wet, black; leaf litter abundant.