P. PEARSON 1951-1952 Observations of Opuntia Dec 11 Lago Siche, 14,500 ft. Many trees near here. Dr. Juan Pulgar calls them "cortenejos". They live in the features hills, out on the short-grass pampas habitat, and in the "carrot" desert. The latter is a most interesting habitat. As one drives past one sees nothing but sand + reddish gravel, sprinkled with tree droppings, the new droppings darker than the substrate because the soil brought up from as little as 6" down is moist where the surface is dry. Close inspection of the surface reveals rather abundant plants, mostly little rosettes of leaves flush with the surface and with a big fleshy tap root. In a 2-ft-square plot I excavated a fistful of these "carrots" (3 or more species). Four shot today, all ff; 1 mm., 2 lactating, 1 preg. No bubbling herd yet in this region, probably all opuntia. Pulgar says they squeal like a mouse. Dec 12 Two ranchers encountered called them Tococoros. Dec 16 Rio Santa Rosa, 13,300 ft. Caught 2 in McAlbee gopher traps among tuffs and features. One between 4 and 7 a.m., the other between 7 am and noon. Both were alive, both caught by hind leg. From their size in relation to gopher trap, both must have been going backward when caught. Both gave quivering noises when handled. Both footed one while digging in a coop lot of dirt with front feet plus simultaneous kicks backward of hind feet. Jan 10 Pampa Vizcaino, 8 am. One feeding on a low root? Senecio? near sand-swipe nest. No dirt at hole, like a gopher feeding hole. Never emerged more than half-way. Would scrape with teeth or front feet at the root in which the hole opened.