ANTHOZOA HYDROIDA. 91 
seems to refer more particularly to the phosphorescence of 
zoophytes. 
While thus with pleasing wonder you inspect 
Treasures the vulgar in their scorn reject, 
See as they float along th’ entangled weeds 
Slowly approach upborne on bladdery heads ; 
Wait till they land, and you shall then behold 
The fiery sparks those tangled fronds enfold—— 
Myriads of living points; th’ unaided eye 
Can but the fire, not the form desery.” 
It has been questioned whether this phosphorescent 
fluid is a secretion of life and health, or the result of some 
partial decay and decomposition. Dr. Johnston thinks that 
this has not yet been ascertained, but seems rather disposed 
to favour the latter opinion. ‘“ No species,” he says, ‘has 
been seen luminous in its natal site, and when undisturbed; 
but after being torn from their attachments, or tossed 
ashore or trodden upon, or carried away to the home of 
the experimenter, and variously irritated, then the tiny 
lamps shine forth momentarily, die away again, and are not 
relit unless some new shock or injury is given.” rom any 
experiments that I have made, I would say that the livelier 
and fresher they were, the more capable they were of lumi- 
nosity. The Sea-pen is of the Asteroida, but I found it as 
