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32 Observations upon Luminous Animals. 
thoms of line no bottom was met with. A bucket of water 
being hauled up, Mr. Langstaff examined it in the dark, 
and discovered a great number of globular bodies, each 
about the size of a pin’s head, linked together. The chains 
thus: formed did’ not éxceed: three inches in Jength, and 
emitted a pale phosphoric light. By introducing his hand 
into the water, Mr. Langstatt raised upon it several chains 
of the Jumimous globules, which were separated by open- 
ing the fingers, but readily re-united on being brought again 
into contact, like globules of quicksilver. The globules, 
he says, were so transparent, that they could not be per+ 
ceived when the hand was taken into the light. 
This extraordinary appearance of the sea was visible for 
two nights. As soon as the moon exerted her influence, 
the sea changed to its natural dark colour, and exhibited 
distinct glittering points, as at other times. The pheno- 
menon, he says, had never been witnessed before by any of 
the company on board, although some of the crew had been 
two or three times round the globe. 
I consider this account of Mr. Langstaff very interesting 
and important, as it proves that the diffused light of the 
sea is produced by an assemblage of minute meduse on the 
surface of the water. 
In June 1806, I found the sea at Margate more richly 
stored with the small luminous meduse than I have ever 
seen it-. A bucket of the water being set by for some time, 
the animals sought the surface, and kept up a continual 
sparkling, which must have been occasioned by the motions 
of individuals, as the water was perfectly at rest. A small 
quantity of the luminous water was put into a glass jar, 
and on standing some time, the medusz collected at the 
top of the jar, and formed a gelatinous mass, one inch and 
a half thick, and of a reddish or mud colour, leaving the 
water underneath perfectly clear. 
In order to ascertain if these animals would materially 
alter their size, or assume the figure of any other known 
species of medusa, I kept them alive for 25 days, by care- 
fully changing the water in which they were placed; du- 
ring which time, although they appeared as vigorous as 
when first taken, their form was not in the slightest degree 
altered, and their size but little increased. By this experi- 
ment I was confirmed in the opinion of their being a di- 
stinct species, as the young actiniz and medusz exhibit 
the form of the parent in a much shorter period than the 
above. 
In September 1806, I took at Sandgate a number of the 
beroe 
