Banks, R.C. 1955 10. 25 November 50 mus. sp. along sides of irrigation ditch or stream, in grass and weeds, approx 2 mi N. Pleasanton, Alameda Co., Calif., 7 ± ft., with J. Ordias. Caught 1 Sorex ornatus (?), 4 ♂ ♀ Mus musculus, 1 Microtus californicus, 1 ♂ Reithro- dontomys megalotis. John did Reithrodontomys and Sorex, I did Microtus and ♀ Mus. (RCB 35-36) Mus had enlarged mammary glands, no embryos, something in uterus may have been placental scars (708). 18 December On 17 Dec. set 50 mus. sp. and 5 rat traps near Galen Frostle's, 1.8 mi. S., 1 mi E. Orinda, Contra Costa Co., Calif. 10 specials were in grassy weeds, 15 in weedy field, 8 were in clearing + Pinus under live oak. All others were in very heavy brush, in a rough line extending up hill. Several wood rat houses in area. A.M., Dec. 18, checked traps with J. Schnell + J. Ordias. Had 5 Reithrodontomys megalotis in grassy weeds, 1 in bushy area, 7 in weedy