‘ 
28 Observations upon Luminous Animals. 
and-ink drawing which was made by Captain Horsburg, 
and accompanied his paper, I have no doubt that both these 
insects were monoculi; the first evidently belongs to the 
genns limulus of Muller; 1 shall therefore beg Jeave to di- 
stinguish it by the name of limulus noctilucus. 
My pursuits, and the state of my health, having fre- 
uently led me to the coast, I have had many opportunities 
of making observations upon the animals which illuminate 
our own scas. Of these I have discovered three species: 
one of which is a beroe not hitherto described by authors; 
another agrees so nearly with the medusa hemispherica, 
that I conceive it to be the same, or at least a variety of, 
that species; the third is a minute species of medusa, which 
I believe to be the Juminous animal so frequently seen by 
navigators, although it has never been distinctly examined 
or described. 
I first met with these animals in the month of October 
1804, at Herne Bay, a small watering-place upon the 
northern coast of Kent. Having observed the sea to be 
extremely luminous for several mghts, I had a considerable 
quantity of the water taken up. When perfeetly at rest, 
no light was emitted, but on the slightest agitation of the 
vessel in which the water was contained, a brilliant seintil- 
Jation was peréeived, particularly towards the surface 3 and 
when the vessel was suddenly struck, a flash of light issued 
from the top of the water, in consequence of so many 
points shining at the same moment. When any of these 
sparkling poimts were removed from the water, they no 
Jonger yielded any light. They were so transparent, that 
in the air they appeared like globules of water. ‘They were 
more minute than the head of the smallest pi. Upon the 
slightest touch, they broke and vanished from the sight. 
Having strained a quantity of the luminous water, a great 
number of these transparent corpuscles were obtained upon 
the cloth, and the water which had been strained did not 
afterwards exhibit the least hght. I then put some sea 
‘water that had been rendered particularly clear, by repeated 
filtrations, into a large glass, and having floated in it a fine 
cloth, on which I had previously collected a number of 
luminous points, several of them were liberated, and be- 
caine distinctly visible in their natural element, by placing 
the glass before a piece of dark-coloured paper. They were 
‘observed to have a tendency to come to the surface of the 
water, and after the class was sect by for some time, they 
were found congregated together, and when thus collected in 
a body, they had a dusky-straw colour, although indivi- 
dually 
