Observations upon Luminous Animals. 33 
beroe fulgens, but no other species: they were of various 
dimensions, from the full size down to that of the medusa 
Sciniillans: they could, however, be clearly distinguished 
from the latter species, by their figure. 
Since that time, | have frequently met with the medusa 
sciniillans on different parts of the coast of Sussex, at Tenby, 
and at Milford haven. I have likewise seen this species in 
the bays of Dublin and Carlingford in Ireland. 
In the month of April, last year, I caught a number of 
the beroe fulgens in the sea at Hastings; they were of va- 
rious sizes, from about the half of an inch in length to the 
bulk of the head of a large pin. I found many of them 
adhering together in the aca: some of the larger sort were 
covered with small ones, which fell off when the animals were 
handled; and, by a person unaccustomed to observe these 
creatures, would have been taken for a phosphoric substance. 
Ov putting a number of them into a glass containing clear 
sea water, they still showed a disposition to congregate upon 
the surface. I observed that when they adhered together, 
they showed no contractile motion in any part of their 
body, which explains the cause of the pale or white colour 
of the diffused light of the ocean. The flashes of light 
which 1 saw come trom the sea at Herne Bay, were proba- 
bly produced by a sudden and general effort of the medusze 
to separate from each other, and descend in the water, 
The medusa scintillans almost constantly exists in the 
different branches of Milford haven that are called pills. I 
have sometimes found these animals collected in such vast 
numbers in those situations, that they bore a considerable 
proporuon to the volume of the water in which they were 
contained: thus, from a gallon of sea water in a luminous 
state, | have strained above a pint of these mieduse. Ihave 
found the sea under such circumstances to yield me more 
support in swimming, and the water to taste more disagree- 
ably than usual; probably the difference of density, that 
has beeu remarked at different times in the water of the sea, 
may be referred to this cause. 
All my own observations Jead me to conclude, that the 
medusa scintillans is the most frequent source of the light 
of the sea around this country; and by comparing the ac- 
counts of others with each other, and with what J have 
myself seen, I am persuaded that it is so likewise in other 
parts of the world. Many observers appear to have mis- 
taken this species for the nereis noctiluca, which was very 
natural, as they were prepossessed with the idea of the fre- 
quent existence of the one, and had no knowledge of the 
‘Vol. 37. No. 153. Jan. 1811. C other, 
