96 HISTORY OF BRITISH ZOOPHYTES. 



tain which were the kinds that sparkled, it was necessary 

 to make the selection by candle-light, and then removing 

 the light to make the experiment. The first I tried was the 

 pretty Valkeria cuscuta, and with it I succeeded in striking 

 light. From Sertularia polyzonias and Cellularia rep fans 

 little light arose. With Laomedea geniculata I was very 

 successful : on this and on other occasions, it not only, 

 when shaken, became very sparkling, but also emitted a 

 strong smell of phosphorus. Membranipora pilosa, var. 

 stelhlata, which spreads itself on a flat frond in a star-like 

 form, became doubly entitled to the name of stellated, as 

 every polype in its little cell lighted up its tiny star, so 

 that for a short time the polypidom became a bright con- 

 stellation. I tried a specimen of Sertularia pumila, re- 

 specting which Stewart, as quoted by Dr. Johnston, says, 

 " If a leaf of Fucus serratus, with the Sertularia upon it, 

 receive a smart stroke with a stick in the dark, the whole 

 coralline is most beautifully illuminated, every denticle 

 seeming to be on fire " but as my specimen had lain too 

 long on the shore, it did not shine, the polypes, I suppose, 

 being dead in their cells. Flustra membranacea, however, 

 was very beautiful. When the seaweed on which, like 

 silver-lace, it had spread, was shaken or bent, as the cells 



