JESimpson, 1938 Dipodomys merriami 2650 ft, La Misión, 2 mi. w. Magdalena, Sonora March 17, 1938 Two taken in mousetraps (baited with oats and alpiste) in rock-sand wash. In the pouches of one (♂33) were very small, brown seeds and a little sand. (other, ♂34) 850 ft, Tinajas de los Papagos, Sierra Pinacate, Sonora March 22, 1938 Two (♀46, ♀47) in mousetraps and one (♂48) in live-traps in the light sand washes which run thru the level, small rock lava field where Perognathus intermedius taken. Cheek-pouch contents of ♂48 saved; others empty. 850±ft., Paso McDougal, Pinacate Region, Sonora March 25, 1938 In sand and bunch-grass and creosote caught 15 (♂510 + 5♀5 ♀emb); put up two (♂73, ♂74); cheek-pouch contents saved. These caught near east base of Sierra Hornaday. 800±ft., Cerro Colorado, 28 mi. w. Sonota, Sonora March 26, 1938 In 50 mouse traps set among creosote in dark cinders which cover the tan desert sandy-soil in a thin layer caught 7 ♀75 and 3♀26. Put up one (♀76) which Dr. Benson had photographed along with a Perognathus intermedius and a P. pencilatus of the same section of desert. No embryos; cheek pouch contents saved.