THE NOCTILUCA MILIARIS. 105 



spectacle well may we be astonished at seeing the cold 

 waters changed as it were by a magician's wand into cradles 

 of fire ! But our admira- 

 tion increases when on 

 enquiry into the causes 

 of the gorgeous specta- 

 cle we learn that it is not 

 the result of inanimate 

 agencies, magnetic or 

 electrical, but that it 

 derives its origin from a 

 living source, and that 

 the Noctiluca miliaris, 



a globular gelatinous Noc tihica mmaris (much magnified). 



animalcule, nearly re- 

 lated to the Rhizopods, is the chief illuminator of the seas ! 



This wonderful little creature is just large enough to be dis- 

 cerned by the naked eye when the water in which it may be 

 swimming is contained in a glass jar exposed to the light ; 

 and a tail-like appendage marked with transverse rings, which 

 serves as an instrument of locomotion, becomes apparent under 

 a slight magnifying power. Near the point of its implantation 

 in the body is a definite mouth leading into a large irregular 

 cavity, apparently channelled out in the jelly-like substance of 

 the body. The external coat is denser than the contained sar- 

 code, and the former sends thread-like prolongations through 

 the latter, so as to divide the entire body into irregular cham- 

 bers. ( The nature of its luminosity,' says Dr. Carpenter, f is 

 found by microscopic examination to be very peculiar, for what 

 appears to the eye to be a uniform glow, is resolvable under a 

 sufficient magnifying power into a multitude of evanescent scin- 

 tillations; and these are given forth. with increased intensity 

 whenever the body of the animal receives any mechanical 

 shock.' 



To fill up the length of an inch it would require 170 

 Noctilucse ranged in a line, and millions could be con- 

 tained in a wine-glass. And yet in every zone they make the 

 wide surface of the nocturnal ocean glow and sparkle with an 

 elfish light. 



Among the microscopic wonders of the ocean, the Polycystina, 



