76 THE FAUNA OF THE DEEP SEA 



as phosphorescent organs, the presence of well- 

 developed and evidently functional eyes in many deep- 

 sea animals, and many other considerations render it 

 very highly probable that some, if not many, forms 

 emit a phosphorescent light. 



The power and constancy of the light emitted, 

 however, must for the present remain a matter of 

 conjecture. We cannot judge at all of the amount 

 of light given out by an animal in deep water by its 

 appearance when thrown out of a dredge upon the 

 deck. Whether the phosphorescent light given out 

 by an Alcyonarian or a Crustacean is more or less at 

 a temperature of 40 Fahr, and a pressure of one ton 

 per square inch than it is at 60 Fahr. and the ordi- 

 nary barometric pressure of the sea-level, is a question 

 that has not yet been brought to an experimental test. 



Whatever the answer to this question may be, 

 the fact remains that a greater percentage of animals 

 from the deep sea exhibit some sort of phosphorescent 

 light when brought on deck than animals that live 

 in shallow water. 



The curious organs possessed by some fishes that 

 are supposed to be organs for the emission of phos- 

 phorescent light have recently been subjected to a 

 minute examination by von Leiidenfeld. 



