Bowley, PT 1942 Microtus californicus Apr. 7 Muddy Creek, 1600 ft., 1 mi. S Chualar Canyon, Monterey Co., Calif. Artemisia californica and grass about 5 to 6 inches tall. Runs of Microtus were apparent in the grass. This specimen is female with 4 embryos measuring 14 mm. Apr. 9 Muddy Creek, 1000 ft., 1 mi. S Chualar Canyon, Monterey Co., Calif. One male and one female were trapped in a line of 127 traps set on the flat in a stand of Artemisia californica with secondary growths of Baccharis sp. and Salvia mellifera. The female possessed 5 embryos measuring 18 mm. She was most peculiar in that she possesses very little hair on her abdomen or hind legs. The mammae were enlarged. It was supposed at first that she was nursing young and the wear and tear of suckling had so denuded her, but the embryos were found within. Or was she this far along in pregnancy while still suckling a former litter? Apr. 10 Johnson Ranch, 300 ft., Chualar Canyon, Monterey Co., Calif. One male and one immature female were taken in a line of 120 traps set on a south-facing gentle slope hillside in a stand of Artemisia californica and grass on the margin of a young grain field.