E. Heste 1982 Journal 2.2 km E (by rd) Trinidad, San Jose Prov., Costa Rica 2600 m 7 July, cont what we are calling Reithrodonomys creper are about 225 mm. long w/ a white-tipped tail - they were caught in mature forest. The small (megalo- size) Reithros were caught in secondary growth near the roadside. One med (lg (~185mm) Reithro was caught that appears to be yet another sp. - it lacks the white tail-tip and has a more orange-colored venter. Also the penis is much smaller than creper. In the latter, the flap on the ? is as large as the penis on the 6 - large for a Reithro! At least 2, maybe 3 sp. of Drytomys, one as large or larger than P. nudipes and one more the size of the R. crepe. We spent the morning making study skins out of all 11 P. nudipes. Began setting traps again at ~1430 in an effort to catch more Heteromys. I set a line of 20 going straight in off the road in mature forest w/ oak + some pine. Leaf litter floor, dense canopy, moderate under story, much rotten wood - floor is soft + sometimes step through it, sinking up to my knees. An additional 40 were set on generally flat terrain near a dirt road a little further east (~500 m). Some areas here have dense viny (brushy understory), but others have only herbaceous ground cover + leaf litter. Canopy is fairly dense, mature broadleaf trees. A final 30 traps were set in a more disturbed area at the