84 THE NATURE OF ANIMAL LIGHT 



Bermuda, which is brilliantly luminous while swarming 

 when the eggs and sperm are shed. It is non-luminous 

 at other times (Galloway and Welch, 1911.) 



(4) Finally, it is possible that animals with com- 

 plex luminous organs, such as squid, fish and shrimp, 

 actually use these as lanterns. It is significant that most 

 of them are deep sea forms, living in a region of perpetual 

 darkness, and it is perfectly logical to suppose that they 

 make use of their light organs for illuminating purposes. 



The whole problem of the use and purpose of luminous 

 organs is an exceedingly complex and difficult one. We 

 have, perhaps, said enough to indicate this and may add 

 that in most cases, so far as opinion is based on actual 

 evidence and observation, that of the layman is of as 

 great value as that of the scientist. 



