Pearson - 1991 up the Rimac Valley in Peru beginning at Chosica: Cereus cactus and shrubs. Very little grazing on the way up but numerous little chacras with alfalfa or walnuts or fruits. Pretty barren by the time we got to 5.6 km of zigzag road below the ski resort at Portillo at 10:30. This is at the bottom of a long long ski lift that ends up at the resort. Stopped there and snooped around a flat on the south side of the road: broken rock somewhat messed up by bulldozing, a small very prickly aromatic Berberis with small narrow leaves, a Chuquiraga-like small bush, a composite, and a lupine-like plant. There was much digging and bocas like tuco-tuco but the mouths open. Hystriomorph-like droppings, some with longitudinal slits. There seemed to be a colony of the animals covering a couple of hectares. Got good looks at several of the animals, even 3 visible at one time all within 5 yards of echother. They excavate like a tuco-tuco, with spurts of earth coming out of the hole, then the animal appears. This animal was black, had white incisors, ears much more conspicuous than those of Ctenomys, tail about like Ctenomys. When they stood up in the mouth of the burrow, like picket-pin ground squirrels, they clearly had a head and neck, unlike Ctenomys. I set three traps in burrows being actively excavated, but after a half hour the animals had not returned to the openings. I think Ctenomys would have returned to close the burrow opening, but this animal doesn't close the opening! We heard no vocalization from them. I think they must have been Spalacopus, although possibly Aconaemys sageii. The latter less likely because of the tuco-like digging procedure. I tried digging one out, but it was too rocky. At the same place were numerous droppings of Buneomys, the right size for the small species, chinchilloides. Then passed through the long tunnel to the Argentine side and dropped down past Las Cuevas but before Puente del Inca where we went north on a side road to Parque Aconcagua and had lunch with a fine view of Aconcagua but overlooking a marshy meadow littered with building materials, a wind-powered generator, metal drums, and other abandoned equipment from some climbing expedition, apparently Brazilian. A little farther down we stopped and snooped on a rocky slope among small Berberis, Acaena, and ?lupine? This had all been under snow recently. Lots of small Buneomys droppings. Lots of hare droppings. No sheep or cow, a little old horse sign. About 1 1/2 hours to clear Chilean and Argentine borders. Then went on down the valley, which is so much barer than on the Chilean side. But the mountains are spectacularly varied in color, much like the Humahuaca Valley in Jujuy. Except for the town of Upsallata there is almost nobody between the frontier or Los Penitentes until beyond Potrerillos. Probably no more people than when Darwin crossed. November 20.- Mendoza. Attended Annual Meeting of SARBM, the Argentine mammal