V. Memmler 1942 Microtus April 1, Berglund Ranch, 1450 ft., 5 mi. N Corralito, Santa Cruz Co., Calif. One ♀ Microtus with five embryos was caught in one of 25 traps set in a meadow between two hilltop ridges. There were typical runways present in the grass. Nuts were used as bait. April 2, Two ♀ Microtus were caught in the same location as yesterday in one of 20 traps. One of these had 6, 4 m.m. embryos; the other had none. Nuts were used as bait. April 4, Mud Creek, 800 ft., 3½ mi. SW San Juan, Monterey Co., Calif. One ♀ nursing Microtus was caught in one of 134 traps set around the sides of a hillside covered with Artemesia Californica. 24 traps were sprung, perhaps due to the heavy rain during the night. Also caught here were Peromyscus and Perognathus. Grass runs up all over the hillside beneath the Artemesia which is about 4 ft. tall. Trails and holes on the slope are not very decided as are those found made by most Microtus. In fact we would not have anticipated there presence. April 5, Jean set 17 traps in the same habitat as about last night, and caught a Microtus. In one of 87 traps set in dense ground cover under live oaks we got another Microtus. One of these was a ♀ with no emb. The other was a ♂.