102 LIVING LIGHTS. 



entirely from the abdomen, and more gradually from other 

 parts ; lingering the longest around the jaws and on the fins. 



" The only part of the under surface of the animal which 

 was free from luminosity was the black collar around the 

 throat ; and while the inferior surface of the pectoral, anal, 

 and caudal fins shone with splendor, their superior surface 

 (including the upper lobe of the tail-fin) was in darkness ; as 

 also were the dorsal fins, back, and summit of the head. I 

 am inclined to believe that the luminous power of this shark 

 resides in a peculiar secretion from the skin. It was my 

 first impression that the fish had accidentally contracted 

 some phosphorescent matter from the sea, or from the net in 

 which it was captured ; but the most rigid investigation did 

 not confirm this suspicion, while the uniformity with which 

 the luminous gleam occupied certain portions of the body 

 and fins, its permanence during life, and decline and cessa- 

 tion upon the approach and occurrence of death, did not leave 

 a doubt in my mind that it was a vital principle, essential to 

 the economy of the animal. The small size of the fins would 

 appear to denote that this fish is not active in swimming ; 

 and, since it is highly predaceous, and evidently of nocturnal 

 habits, we may, perhaps, indulge in the hypothesis that the 

 phosphorescent power it possesses is of use to attract its 

 prey, upon the same principle as the Polynesian Islanders 

 and others employ torches in night-fishing." 



