214 THE ARCTURUS ADVENTURE 



four hundred fish of twenty-six species. Up to 

 6.30 in the evening all the more abundant surface 

 fish of the daytime were captured, such as pilot 

 fish, half-beaks, flyingfish and young Seriolas. 

 After this, not one was ever seen, but promptly at 

 7 o'clock six species of lantern fish, Myctophid, 

 appeared, and a half hour later their enemies, such 

 as Astronesthes, were taken. In early morning 

 the reverse occurred, and only one species of lan- 

 tern fish ever lingered after 4.30 a. m. up to which 

 time they were taken in dozens (Plate V). 



In the case of most oceanic organisms we cannot 

 tell by a casual examination whether they are 

 diurnal or nocturnal, but even if we had never seen 

 a living lantern fish, their equipment of lights, 

 like that of fireflies, could mean nothing but a life 

 spent in darkness. This luminescence in sea crea- 

 tures has always held a great fascination for me, 

 and when first I saw among a mass of plankton 

 several of these fish, it was a memorable event, — 

 like my first electric eel, or my last glimpse of the 

 Himalayas. My interest in the subject was 

 whetted when I had translated a recent resume of 

 the subject and found that nothing but casual and 

 fragmentary observations on living luminescent 

 fish had been made, and these mostly by fishermen. 



Several times I rushed to the photographic dark- 

 room with a dead or dying specimen, to see nothing 

 but the gleam from the numerals of my wrist 

 watch. Then one evening I filled a small aquarium 

 with cool sea water and placed in it three newly 

 caught Myctophids. Suddenly one of them flashed 



