176 Cruise of the "Alert." 



the sea-level, was the entrance to the caves, a narrow aperture 

 in the upraised coral rock, leading by a rapid incline into a 

 spacious vaulted chamber, from whose gloomy recesses dark and 

 forbidding passages led in various directions. In the floor of the 

 chamber were deep pools of water, probably communicating with 

 the sea, and said to be tenanted by a species of blind eel, about 

 two feet long, which we were told the natives sometimes caught 

 with hook and line, and fed upon. I was provided with fishing- 

 tackle for capturing a specimen of this singular creature ; but as 

 several of our party were induced to relieve themselves of the 

 intolerable heat of the cave by bathing in these pools, the fish 

 were probably scared away, and I was unable to obtain a single 

 specimen. 



The rock pierced by the caverns was everywhere of coral 

 formation, and as water freely penetrated through from the 

 soilcap above, the roof and floor were abundantly decorated with 

 stalactites and stalagmites in all their usual fantastic splendour. 

 I noticed that many parts of the floor of the cave were speckled 

 with white spots resembling bird-droppings, on which drops of 

 water were frequently falling from the roof above, and I formed 

 the opinion that the white colour of these spots was due to the 

 drops of water which pattered on them having traversed a portion 

 of the ground above, from which they did not receive a charge of 

 lime salts, and consequently washing clean the portion of the 

 coral floor on which they fell, instead of depositing thereon a 

 calcareous stalagmite. This surmise was strengthened by observing 

 the absence of stalactites depending from the roof in these 

 situations. 



Numbers of small swifts, apparently the same species which is 

 common on the island {Collocalia spodiopy&ia), flitted about the 

 vaulted parts of the cave, looking in the torchlight like bats, 

 which at first sight I felt sure they must be, until our native 

 guide succeeded in catching one specimen, which resolved our 

 doubts. We traversed the more open parts of the cave to a 



