Animal Luminescence 583 



opaline spots projected a phosphorescent splendor, making this mol- 

 lusc one of the most brilliant products of nature. ... It probably 

 lives at great depths." 



Knowledge of the large number of deep-sea luminous squid came 

 as a result of the great exploring expeditions, pioneered by that 

 of the Challenger in 1873-1876, and followed by others of every 

 nationality. 



The first histological studies of squid were made on Histioteuthis 

 Ruppeli by L. Joubin in 1893-1894, to be followed by many others 

 in the next century. 



Crustacea 



OSTRACODS 



Allied to the Copepods but considerably larger and a striking 

 sight to the unaided eye at night, ostracod luminescence was noticed 

 as early as 1754 by Godeheu de Riville (1760) off the Malabar coast 

 of India and the Maldives. At nine o'clock in the evening on the 

 fourteenth of July, 1754 (the fall of the Bastille did not take place 

 until 1789) , he saw to his great surprise that the sea " was covered 

 over with small stars; every wave which broke about us dispersed 

 a most vivid light, in complexion like that of a silver tissue electri- 

 fied in the dark. . . ." *" 



Riville noticed that the light specks stuck to the rudder, and on 

 collecting sea water and filtering it through a handkerchief, the 

 brilliant points stuck to the handkerchief. With the magnifying 

 glass a sensible motion was perceived, and Riville observed, 



notwithstanding the light of two candles, we saw issuing from its body a 

 blueish and luminous liquor, the glare of which extended to the distance 

 of two or three lines into the water. I took it upon the point of the 

 tongs, and it was no sooner placed under the microscope than it yielded 

 again a considerable quantity of the same azure liquor; notwithstanding 

 I had the satisfaction of seeing it still full of life, and moving with much 

 vivacity. 



Riville's drawing, reproduced as figure 46, leaves no doubt of the 

 fact that his luminous speck was an ostracod, one of the marine 

 forms characterized by the abundant luminous secretion poured 

 from large gland cells near the mouth, whenever they are irritated. 



Such a striking behavior was noticed by many other explorers of 

 the sea during the nineteenth century. Histological studies were 



*' From the translation in the Gentleman's Magazine 38: 408, 1768. The Riville 

 account appeared in the Memoirs of the French Academy of Sciences for 1760. 



