72 LIVING LIGHTS. 



CHAPTER X. 



BY CRAB-LIGHT. 



IN drifting over the calm waters of the ocean as night 

 comes on, we notice in the depths below luminous forms 

 of infinite variety. These are medusce, as we have seen, 

 moving here and there like veritable comets. They approach 

 so near the unruffled surface, at times, as to expose the gleam- 

 ing disk. The nets of the fishermen come up entangled in 

 their golden trains, and along shore processions and columns 

 of these wondrous shapes pass and repass. 



As the night grows apace, and the wind rises, they sink 

 into the deeper waters : yet the foam and crest of the waves 

 still give out the curious light, though now from another 

 source. Much of this is due to Crustaceans, minute crea- 

 tures often almost invisible to the naked eye, yet possessing 

 this wonderful gift of phosphorescence to a marked degree. 



Some species of the little Gammarus are remarkable for 

 their clear silvery light. They are familiarly known as 

 water-fleas, attracting attention from their leaping powers, 

 and are often found under seaweed above high- water mark, 

 darting here and there in incredible numbers when their 

 home is disturbed. These forms are extremely valuable as 

 scavengers. 



That these interesting animals were light-givers, has long 



