VIRGULARIA. 197 
and that when roughly touched in the dark, a transient 
gleam of light was emitted. A very interesting statement 
as to this phosphorescence may be found in Dr. Johnston’s 
‘History of British Zoophytes,’ from which we shall extract 
only a little. From experiments made by himself and Pro- 
fessor E. Forbes, and others, they were led to infer, first, 
that the polype is phosphorescent only when irritated by 
touch ; secondly, that the phosphorescence appears at the 
place touched, and proceeds from that to the extremity of 
the polypiferous portion; thirdly, that only those parts 
above the place touched give light ; fourthly, that the light 
continues longest from the part touched; fifthly, that sparks 
of light are sometimes sent out when the animal is pressed, 
and these were found to arise from ejected spicula. 
Genus XVII. VIRGULARIA, Lamarck. 
Gen. Char. Polype-mass free, linear-elongate, supporting, to- 
wards the upper extremity, sessile lunate lobes, embracing the 
stem obliquely, and bearing a row of cells on their margin.— 
Johnston. 
1. VIRGULARIA MIRABILIS, Sea-rush, Mr. Simmons. (PI. 
XII. fig. 40.) 
