MEDIIS.E OR JELLY-FISH. 41 



by navigators as resembling * white-hot shot,' visible at some 

 depth beneath the surface." * 



The phenomenon is not, however, confined to warmer lati- 

 tudes. Sir Walter Scott, in his " Lord of the Isles," has de- 

 scribed it in our own seas : — 



"Awaked before the nishinjj prow, 

 The mimic fires of ocean glow, 



Those lightnings of the wave ; 

 "Wild sparkles crost the broken tides. 

 And, flashing round the vessel's sides, 



With elfish lustre lave, 

 While, f.ir behind, their livid light 

 To the dark billows of the night 



A gloomy splendour gave." 



The power of emitting light is possessed bv several species 

 of marine animals, among the Polypes, Annelids, Crustacea, 

 and Mollnsca. It was formerly a question, to what cause the 

 luminosity of the sea was to be attributed ? By some philo- 

 sophers it was supposed to be owing to the decay of animal 

 substances Avhich it contained; while others conjectured that 

 it arose from a kind of electricity peculiar to itself. These 

 hypotheses are now abandoned, and it is universally admitted, 

 that the phosphorescence of the sea is owing to that of its 

 living inhabitants, more especially of those which belong to 

 the present order; and it has been found, that the species of 

 Medusaj most instrumental in producing the luminosity of the 

 ocean, are those which are the most minute. 



Perhaps no writer has succeeded in giving a clearer idea of 

 the myriads of small Medusa? with which great tracts of the 

 sea are peopled, than Scoresby. On examining a bucket of 

 the olive-green water of the Greenland sea, he found its pe- 

 culiar colour was owing to the multitude of minute Medusa; 

 which it contained. "They were about the one-fourth of an 

 inch asunder. .In this proportion, a cubic inch of water 

 must contain 64; a cubic foot, 110,592; a cubic fathom, 

 23,887,872; and a cubical mile, 23,888,000,000,000,0001" 

 " Provided the depth to which they extend be but 250 fathoms, 

 the above immense number of one species may occur in a 

 space of two miles square. It may give a better conception 

 of the amount of Medusae in this extent if we calculate the 



* Outline of the Animal Kingdom, psge 77. 



