2O6 ELECTRIC POWER OF ANIMALS 



I 



shallow water. We have occasionally seen it in 

 Narragansett Bay, gleaming with the dip of the 

 oar, or the paddling with the hand. 



The most common source of diffused luminosity 

 is a minute animal, nearly globular, having the ap- 

 pearance of a lump of homogeneous jelly, and 

 provided with a stalk-like appendage. Microscop- 

 ically, it is found to consist of a sac with definite 

 walls, having its interior which is for the most 

 part filled with fluid traversed by a network of a 

 more consistent gelatinous substance, containing 

 numerous cells ; the size and form of which are 

 continually undergoing alterations. It has been 

 proved by Dr. Pring, that water containing nocti- 

 luccz, when subjected to a magneto-electric current, 

 after a time gives out a steady and continued 

 flow of light from the whole of the water ; the 

 surface of which appeared spangled with number- 

 less persistent points of light. The light ceases 

 after a quarter of an hour, and cannot be re- 

 produced, evidently in consequence of the death 

 of the animals. 



" Of all radiated animals, the acalepha are the 

 most distinguished for luminosity. The light is 

 emitted particularly round the tentacula, and from 

 the ciliated surfaces during the movements of the 

 animal ; it seems to proceed from a very acrid 

 mucus secreted from the integument. 



"The luminosity in many of the marine annelida 

 is not a steady glow, but a series of vivid scintil- 



