E. NEWTON HARVEY 13 



wave of light which spreads over a pennatuHd colony stimulated at 

 one point was observed by L. Spallanzani in 1783 and has excited the 

 interest of investigators ever since. 



Marine annelids are much more diverse than the coelenterates in 

 methods of light production. Some secrete from epidermal glands, 

 some exhibit intracellular luminescence. The color of the luminescence 

 varies from yellow to blue. A luciferin-luciferase reaction has been 

 demonstrated in Odontosyllis, and this worm offers special advantages 

 for chemical study, as it swarms in large numbers at Bermuda and 

 other places in relation to phases of the moon. In annelids, the nerv- 

 ous control of luminescence is particularly favorable for study and 

 has been thoroughly investigated by Nicol in Chaetopterus (1952) 

 and in polynoid worms ( 1953 ) . 



Earthworms are a favorable group for chemical studies. Reference 

 has already been made to the Czech investigations. In addition to 

 the part played by flavins in luminescence, attention should be par- 

 ticularly directed to the fact that one species of the genus Eisenia may 

 be luminous and another species not, even though closely related. 

 What is lacking in the nonluminous species? Cross breeding should 

 be attempted. Study of such intercrosses between varieties of the 

 fungus Paniis stipticus has already given interesting results (Macrae, 

 1942). 



Among molluscs, very little has been added to the chemistry of 

 light production since the work of Dubois, which is summed up in 

 his 1928 article in Richet's Dictionnaire de Physiologie, Vol. X. Pholas 

 is extraordinarily favorable for chemical work, and should be attacked 

 by modern methods. 



Self-luminous squid offer many species with complicated luminous 

 organs for physiological work, but they are mostly deep sea forms, 

 rare and unfavorable for chemical studies, with the exception of 

 Watasenia scintillans, which breeds in enormous numbers during 

 April-June in Toyama Bay on the western coast of Japan. Nerve 

 and possible hormone control of the lighting mechanism presents an 

 untouched field for investigation. 



Among Crustacea, ostracods, copepods, mysids, and decapod shrimp 

 all produce an external secretion, often in great abundance. It might 

 be expected that luciferin from one species would react with luciferase 



