Hoop Reithrodontomys m. longicaudus 1 mi. E mouth San Pablo Cr (salt marsh), Contra Costa Co., Calif. Oct. 25, 1936 4 specimens taken in live (Benson) traps placed 6 ft. apart in Microtus runs chiefly, + in Salicornia. Jan. 13, 1937 4 specimens taken in snap traps baited with oatmeal and placed about 10 paces apart in Microtus runs. 1 R. raviventris taken in same trap line and in same habitat (Salicornia). Giant (salt marsh), Contra Costa Co., Calif. Feb. 15, 1937 4 animals taken (1 in can trap - retained alive; 3 in snap traps) in Microtus runways in Salicornia. No other kinds of harvest mice taken here; house mice and shadow mice were taken. 1 mi. W Avon (salt marsh), Contra Costa Co., Calif. Feb. 28, 1937 4 specimens taken in snap traps baited with oatmeal and placed in Microtus runs in Salicornia. Caught on same trap line (and in at least one instance