JESimpson, 1938. 74. 500±ft., 2 mi. e. Punta Arenas, 75 mi. w. Hermosillo, Sonora. May 9, 1938, continued. ♂ 528-330 and ♀ 331), 8 Peromyscus eremicus (♂ 332), and two juvenile Neotoma albigula. Shot snake (333). Broke camp and drove toward Punta Sargenta in hope of a ferry across the channel to Tiburon Island; however, we found that, contrary to informat- on at Bahia Kino, the road did not go all the way to the point, but it stopped at a one-shack provision point for the fisherman. No one was there nor any boats in sight; so we back-tracked and drove to: Sierra Seri, Hermosillo, Son. 650 ft., Sierra Serri 9 mi. w. Rancho San Javier, 70 mi. w. May 9, 1938, continued. Set 50 mousetraps on rocky-ground, rocky-hill among torote, creosote, palo verde, and ocotillo. May 10, 1938. Caught 5 Perognathus intermedius (♂ 334, 335 and ♀ 336-38), 1 Perognathus penicillatus (♂ 339), Perognathus baileyi, (♀ 340), and 2 Peromyscus eremicus (♂ 341, 342). Shot a lizard (343). Cheek-pouch contents of pocket mouse dried. Broke camp and drove back to Rancho San Javier for a supply of water (slightly salty). On way back to same locality shot a roundtail ground squirrel, Otosillus tetricaudus (♀ 344), at 4 mi. w. Rancho San Javier, 65 mi. w. Hermosillo, Sonora. Drove on in Sierra Seri to break camp at approximately the same place as yesterday: