Murray 1948 Journal May 24 Las Cuevas, 23°34'N, 109°39'W, Baja Calif. Relifer, packed so tightly that none of the wall showed through. We estimated very roughly that 60 square feet were so covered. In one crevice were many Natalus mexicanus, packed tightly, and hung on the roof was another small clump of the same kind. Also on the roof were a few Macrotus californicus, grouped together but closely surrounded by Myotis. All were very inactive. It was necessary to scrape with a net to get the bats off of the wall, and to poke vigorously in the crevice. Those which fell on the ground began to crawl rather than fly. Later they became more active and excited, and began a loud chorus of chittering where there were but a few seconds before. A few began to fly restlessly about, and then quite a number when stirred up by the net. By then they struggled and tried to bite when caught and flew away readily. The temperature in the cave was fairly low for those which we have seen. The floor was thickly covered with dust and guano. Estimated the total number 15000. A short distance away we looked into