Life of the Waters 355 



crest of a wave break into myriad opalescent drops, can fully 

 appreciate the beauty and the wonder of this strange, un- 

 canny light. The physiology of light production in animals 

 is not yet well understood. It is known to be due however 

 to some secretion which combines readily with oxygen, this 

 action producing the light. Phosphorescence is by no means 

 limited to deep sea animals, nor do all of the latter possess it. 

 One of the most interesting cases of light production is 



DEEP SEA FISHES AS SEEN AGAINST A DARK BACKGROUND 

 Photograph of a group in the American Museum of Natural History 

 in New York. 



Courtesy of the Museum. 



that of the deep sea angler fish, Gigantactus, where the snout 

 is modified to form a luminous organ, suspended on a stalk 

 above the head of the fish. This organ is supposed to act 

 as a lure to attract smaller fish which readily fall victims 

 to the angler's appetite. 



The occurrence of eyes in deep sea fishes forms a very 

 perplexing problem. In some the eyes are large, and in others 

 extremely small or entirely lacking. By analogy with the 

 cave dwellers among land and fresh water animals, we should 

 expect the deep sea fishes to be blind. But on the other hand 



