JESimpson, 1938 p.2. Peromyscus eremicus (continued) 900±ft., ½ mi. s. Crater Elegante, 34 mi. w. Sonoita, Sonora March 27, 1938, continued. thru the lava field; plants here are palo verde and mesquite, mainly. March 28, 1938 The second night of aforementioned trap-line netted only one mouse (0♂); not put up. Another taken farther up the wash on similar ground in live-traps; a♀ which was turned loose — ran over the lava, once started by shooting, without stopping for cover or survey. 1100±ft., Crater Elegante, 34 mi. w. Sonoita, Sonora. March 29, 1938 Three (2♂s + 1♀) on rim of crater among ochotillo [noemb.] and creosote. Two (1♀and 1♂) taken on red-lava hill at south rim of crater among sparse cholla and ochotillo. 50±ft., Punta Peñasca, Sonora. April 1, 1938 2♂ plus 0♂/106 taken in lava on lee-side of hill from bay of Gulf; the latter of lighter pelage than those taken by party here and elsewhere. April 2, 1938 12 (8♂; 4♀'s [noemb].) on windward side of above mentioned lava hill; none saved. 50±ft., Cerro La Cholla, 6 mi. wnw Punta Peñasca, Sonora. April 3, 1938. A ♀ plus ♂/112 and ♀/113 taken on granite hill ochotillo, & cholla. [noemb.] among creosote.