210 TOILERS IN THE SEA. 



touch ; (2) The phosphorescence appears at the 

 place touched, whether it be the stalk or the polyp- 

 bearing part, and proceeds from thence in an undu- 

 lating wave to the extremity of the polyp-bearing 

 portion, and never in the other direction ; (3) If the 

 centre of the polyp-bearing portion be touched, only 

 those polyps above the touched part give light ; and 

 if the extreme polyp-bearing pinna be touched it 

 alone of the whole animal exhibits the phenomena 

 of phosphorescence ; (4) The light is emitted for a 

 longer time from the point of injury, or pressure, 

 than from the other luminous parts ; (5) Sparks of 

 light are sometimes sent out by the animal when 

 pressed : these are found to arise from luminous 

 matter investing ejected spicules. Subsequently the 

 same observer writes that " unless the animal be in 

 the highest state of vivacity, the stalk shows no 

 phosphorescence, and the light of the feathered 

 portion only runs a short way, but always towards 

 the upper extremity. When plunged into fresh water 

 the sea-pen scatters sparks in all directions, a most 

 beautiful sight, but when plunged into spirits, it does 

 not do so, but remains phosphorescent for some time, 

 the light dying gradually away, and last of all from 

 the uppermost polyps." A further number of ex- 

 periments were made with the view of ascertaining 

 whether the light was produced by electricity, and 

 the results are given in Johnston's " Zoophytes " to 



