MARINE PHOSPHORESCENCE. 323 



broad, flat margin, which, when viewed at night, and 

 in the living animal, is seen to be studded with a row 

 of luminous dots, placed equidistant from each other, 

 and shining with a delicate blue light. When the 

 creature is allowed to be quiet, the luminous display 

 is confined to this series of dots ; but when irritated by 

 handling, (or, we will suppose, by the agitation of the 

 waves,) the entire body emits a powerful light ; which 

 is not, however, so clear and fixed as that of the 

 Pyrosome, but has rather a rough or powdered appear- 

 ance. A slimy secretion, which is easily removed from 

 the body of this medusa, also shines brightly when 

 rubbed, and appears like many twinkling stars, vanish- 

 ing and again lighting up, and seeming to run from 

 spot to spot. When these creatures are assembled in 

 their natural element, they present as many circular 

 patches of light, gleaming brightly, and the more 

 vividly where the sea most breaks : their lights undulat- 

 ing with the waves, alternately appearing and vanish- 

 ing, and passing as it were suddenly to different parts 

 of the ocean, otherwise in obscurity, giving the effect 

 of many torches moved quickly through the depths of 

 a dense and darkened forest. 



A second species is a very curious medusa, (indepen- 

 dent of its luminous economy,) and was also commonly 

 captured in many parts of the North Pacific. It is 

 about three inches in length by two in circumference ; 

 of a somewhat cylindrical form, slightly tapered at one 

 extremity ; is perfectly transparent and colourless ; 

 and has the crystallized appearance of cut-glass. The 

 entire animal is composed of an aggregation of numerous 

 smaller crystal-like parts, each closely resembling the 

 other in its shape, which is that of the slice of an 

 orange, cut vertically. These individual parts are but 



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