ITS LAMPS OF LIGHT. 335 



spicuous. I went into my study after dark without a 

 candle, to try whether any of the captives in the 

 different vases were luminous, I took a slender stick 

 and felt ah out in the water at random ; presently I 

 touched something soft, and instantly a circle of 

 bright little lamps was lighted up, like a coronet of 

 sparkling diamonds, or like a circular figure of gas 

 jets, lighted at a public illumination, and seen from a 

 distance ; more especially as some of the constituent 

 sparks appeared to go out, and revive again, just as 

 do the gas-flames if the night be windy. The phos- 

 phorescence, though but momeutary, was renewed as 

 often as I touched' the animal, which was not very 

 often, as I feared to injure it. 



As this was the commonest species of Medusa here, 

 as its structure is simple and may be taken as normal 

 in the tribe, and as it belongs to a genus that in- 

 cludes by far the largest number of British species, I 

 will describe it in detail as a sample of the rest. 

 _ It consists of an umbrella- shaped bell of clear 

 colourless jelly, like a watch-glass, if you imagine it a 

 great deal thicker in the centre than at the margins ; 

 but sometimes becoming hemispherical in outline. 

 The inner surface of the bell is lined with a skin 

 equally gelatinous transparent and colourless with the 

 former, but often minutely wrinkled, and generally 

 easy to be distinguished by its appearance : this is 

 called the sub-umbrella. From its centre depends a 

 very moveable, flexible peduncle, composed of more 

 substantial flesh than the bell, and evidently cellular 

 and fibrous. In this genus it is small, but in some 

 it protrudes beyond the margin of the bell ; it gene- 



