Y. HANEDA 



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Fig. 7. Photo of Cypridina Mgendorfii from Japan. 



luminescence can be restored with moisture. This Cypridina species 

 Hves on the sandy bottom near the shore and comes out to feed at 

 night. There are several methods of collecting Cypridina. During 

 World War II, Japanese army officers used large earthenware pots 

 baited with fish, which they lowered to the sandy bottom at night. 

 This method was not too satisfactory because nonluminous Crustacea 

 and marine snails were mixed with the Cypridina. A simple method 

 for mass collection is to tie fish heads to long strings and suspend 

 them in the sea at night. Cypridina gather on the fish heads and may 

 be easily caught. The living specimens are then placed on blotters in 

 sunhght to dry, or in a heater with a low temperature. If dried while 

 still alive, the two hinged valves become transparent, and a bril- 

 hant luminescence appears on moistening; if dried after death, the 

 valve changes to a nontransparent white, and the luminosity is weak. 



The Mihtary Institution of Japan during World War II was plan- 

 ning to utilize Cijpridina light for reading at night. I saw some sam- 

 ples of Cypridina powder in Singapore which were sent from Japan, 

 but in tropical countries the powder putrified very rapidly when 

 moistened, and I do not know whether it was useful or not. 



Cypridina noctiluca, shown in Fig. 8, is a tropical species com- 



