B. Nielderson 934. Microtus californicus californicus. May 24 1/4 mi E & S stadium, 700 ft. Berkeley Alameda Co. Calif. Caught in a moist grassy thicket. The habitat was an open grassy hillside with small scattered clumps of dried thistle. In and about this type of cover there were numerous runways and small openings to burrows. The widths of the burrows varied from 1 in. to 1 1/2 in. The runways were cut deeply in the grass which afforded protection. Apr 4 1/4 mi E & Stadium, 700 ft. Berkeley Alameda Co. Calif. Of the four young microtus taken on this late #374 and #375 were found in or near a nest with another individual of the same family. The other two Microtus #376 & #377