V. Memmler 1943 Peromyscus maniculatus June 2, Indian Creek 1500ft., 13 miles S. Shandon, ShO Co., Calif. on light colored sandy soil near Lotus, Chorizanthe & Monardella. The area was flat where traps were set, but the country was hilly in general with Adenostoma covered slopes and Digger Pine trees sca- ttered about. June 3, Santiago Springs, 2100ft., 8 mi. E + 1/2 mi. S Simmler, ShO Co., Ca. Four adult σ's were caught in 50 snap traps set near the top of a north facing hillslope covered with a scattered growth of Junipers and abundance of Stanleya pinnata. The slope was quite steep. June 4, In 50 traps left in the same places as last night I caught 3 σ's + 2 φ's. June 6, In 47 live traps I caught 2 min. σ's and 1 adult φ. These traps were set along a creek bank. The creek was dry or stagnant. There were many holes in the bank and runways at its base. The day before 18 Perognathus califor- nicus were caught in the same area and 2 Perognatus imonatus. Today 7 Perognathus californicus were caught. It would therefore seem that the P. californicus, pocket mouse is the dominant animal here rather than the Peromyscus.