298 CLASSIFIED RESUME OF ORGANISMS OBSERVED 



and once, at 550 feet, a jet-black, three-inch jelly passed 

 the window. In spite of their usual transparency, however, 

 even small jellies at the lower levels could be seen far out 

 near the end of the beam, forty-five feet away. 



Luminescence was relatively rare in this group, being 

 reported only about ten times, that is, in about one-eighth 

 of all the medusse. One small luminous jelly was seen at 

 400 feet, the others between 800 and 2100. When the 

 source of the illumination could be determined, it was 

 found to arise variously, from luminous bands on the um- 

 brella, from a luminous spot at the base of each tentacle, 

 from eight pale blue spots on the edge of the umbrella, or 

 from the tentacles themselves. Once, at 1650 feet, an entire 

 school was brilliantly illuminated with pale green lights. 

 One of the largest medusas seen, which measured fully a 

 foot in diameter, seemed to have luminous food in its 

 stomach, although it did not carry lights of its own. 



The majority passed singly, or rarely in loose groups of 

 from several up to thirty or more. Their pulsations at the 

 lower depths were as rapid and rhythmical as near the sur- 

 face, and once or twice small jellies showed unusual activ- 

 ity, spinning around in the beam. Usually, however, the 

 beam had no effect upon them whatever. 



The only genera which could be identified with certainty 

 were Aurelia (reported six times between 20 and 170 feet, 

 and once at 11 50 feet) and Limiche (identified five times, 

 between 100 and 350 feet). 



In the trawling nets small jellyfish are common, and. 



