ESPERANZA TO CAYO HUT I A 53 



swarm about the light. Fish up to four or five 

 inches in length circle rapidly about it forming a 

 revolving wheel of some eight to ten feet in di- 

 ameter. This we called the "Life Wheel." Inside 

 this revolving circumference and nearer the bright 

 bulb, myriads of plankton dart about confusedly as 

 though greatly excited and fascinated by it. This 

 method of fishing brought easily and quickly to 

 our collections a great quantity of organisms that 

 otherwise could only have been captured by 

 uncertain laborious process. The amount of our 

 catch differed very greatly according to type of 

 bottom and possibly to weather conditions. This 

 was one of our most successful nights with the 

 light. Until one has actually had experience with 

 the submarine light one can form no true concep- 

 tion of the abundance of living organisms that 

 swarm in the warm sea water of the tropics. 

 Within the circle of bright light about the bulb 

 every cubic foot of water harbors at least a 

 hundred living creatures without counting a 

 vastly greater number of organisms not visible 

 to the naked eye. Probably seventy-five per cent, 

 of the whole are larval, — velagers of mollusks, the 

 megalops of Crustacea, newly hatched medusae, etc. 



