JESimpson, 1938. p.4. Dipodomys merriami (continued). 1400+ft., 1 mi.ne Sonoita, Sonora. April 10, 1938, continued. Contrasting with the above was the catch of 14 Dipodomys merriami (8 o; 6 ♀; cheek-pouch contents saved.) from 23 mousetraps set in the sand and sage(2) area bordered by the dense mesquite. The ground cover is heavy between the typical kangaroo-rat area and the dense mesquite; here with open ground and an abundant food supply the rats abound. The rats are here (as in other places seen) most abundant in more or less open ground; this may be correlated with the large eyes and expanded bullae of the rat. 900+ft., 1.6 mi. sw Las Alesnas, 20 mi. wsw Cabona, Sonora April 18, 1938 Caught 15 among creosote in sand; put up 5 o: 188-192 ; Dr.Benson put 5 ♀'s; the party catch totaled 48 : 30 o> and 18♀; cheek-pouch contents saved. April 19, 1938. Caught 4 o> and 2 ♀ along same trapline as yesterday; none taken in live-traps in similar area. Cheek-pouch contents saved. 200+ft., 3 mi. n.Puerto de Lobos, Sonora. April 22, 1938. o>225,226 and ♀ 227,228 caught among white-brush pouches only border and creosote at border between dark lava and light sand.