92 HISTORY OF BRITISH ZOOPHYTES. 
luminous as those of the Hydroida. J had not the oppor- 
tunity, indeed, of trying the experiment on it in the sea, 
but when quite alive in a vase of sea-water, I found that it 
emitted, when smartly touched, a flash of phosphorescent 
light. When I brought hydroid zoophytes from the sea 
in a close vasculum, the sea-water adhering to the seaweeds 
kept them as much alive during the transit, occupying less 
than half an hour, as if they had remained on the rocks on 
which the seaweeds grew, and where many of them, during 
every ebb-tide, are quite deserted by the sea. Taking them 
into a darkened room half an hour after they were removed 
from the rocks, I found the phosphorescent light, when they 
were shaken, quite brilliant. The experience of Mr. William 
Thompson, of Belfast, an accurate observer, seems to have 
been the same. He remarks, “I do not think it probable 
that the luminosity of zoophytes is caused by partial decay 
and decomposition, as I have, especially in the month of 
January, 1834, and frequently since, observed many species 
to put forth their lights vigorously a very few hours—cer- 
tainly within three—after I had dredged them from the 
bottom of the sea. They were not sooner looked at, because 
it was not dark till about that time after their capture. 
Torn from their attachments these certainly were, but they 
