SMITHSONIAN EXPLORATIONS, I929 65 



guano heap. We had noticed the pecuHar clicking sound made by 

 bats but had seen only a small number clinging to the ceiling of the 

 cave, so we decided to investigate more thoroughly the source of the 

 noise. We crawled carefully up the guano heap toward the crevice, 

 and when within about two feet of the hole, noticed a great amount of 

 heat coming through the opening, together with very strong ammonia 

 fumes, and we could hear the swishing of large numljers of wings. 

 Perrygo and I placed our electric lanterns through the opening and 

 turned them on. Immediately there was a terrific noise resembling 

 that of a hurricane, and liats flashed past our heads by the hundreds. 

 Beyond this tiny opening was concealed another cave or chamber as 

 large as the entire outer cave, and in it were hundreds of thousands of 

 bats. A few hours later, after the bats became quiet again, we took 

 another look at them. It was a wonderful sight. As far as the 

 rays of the electric lantern would carry, great masses of bats could 

 be seen clinging to every available inch of ceiling and walls, some 

 of these masses being as large as a bushel basket, while thousands 

 were in flight. From observations and specimens taken, only two 

 species appeared to occupy this great roost. Four days were spent 

 working this cave. 



On January lo we started work in a large cave near San Rafael 

 which had been partially worked during the previous season. Foiu- 

 days were spent here with fair results, a fine series of jaws of the 

 small insectivorous animal being obtained. 



Two days were spent working in a large cave situated about 35 

 miles southeast of Don Don. The opening was situated about 100 

 feet back from, and about 30 feet above, the river level, and although 

 the cave appeared to be just the type to contain extinct mammal and 

 bird bones, relatively small numbers of bones were found, these 

 consisting chiefly of rats and bats. 



Because our line of work was dififerent from anything the people 

 of this section had seen before, we were visited daily by hundreds 

 of natives eager to watch our every move. The consequence was, 

 that we were unable to give proper attention to the preparing of our 

 collection. At San Rafael and at Don Don, among our various col- 

 lections, we had taken five live snakes, commonly known as tree boas, 

 which we kept in a large gunny-sack. Knowing the natives greatly 

 feared snakes, and believing it would keep them away from the door 

 so that we might get enough light to work by, we hung the bag on the 

 guide rope attached to the front of the tent. It did not take long for 

 one of the natives to discover that the bag contained live snakes, and al- 

 though temporarily it kept them away from the entrance, the news 



