Luminousness of the Sea. 3138 
Medisa scintillans. I have copied both of these figures 
(fig. 82. a b, c d); and perhaps it may be found that 
both of these, and mine also, 
are the same animals, These 
little bodies were generally to 
be seen when the water was 
luminous, and at times were 
very abundant, especially in 
straits and near land. ‘Their 
real size, I have already said, 
was generally about that of a 
grain of sand; but, when seen 
shining in the water, their ap- 
parent size was very much 
increased. Upon taking up a bucketful of water from along- 
side, and pouring it upon the deck, innumerable spots might be 
seen about the size of small peas, which, when taken up on 
the finger and carried to a light, were scarcely discernible by 
the naked eye. Magnified thus by the refraction of the 
water and their own light, when the countless millions of them 
are scattered about upon the surface of the sea, upon its being 
agitated and set in motion by the ship’s way through it, the 
appearance then presented is beautiful in the extreme. 
Though these little animals were the most abundant per- 
haps of any, there were several others that were also very 
numerous; and first those represented in fig. 81. ¢ deserve 
to be mentioned. They occurred very frequently in the 
open ocean, in straits, and near land, and were most abun- 
dant at those times when the sea was very luminous. The 
natural size of these bodies is about half that of a pin’s head ; 
they seem to consist almost entirely of numerous tentacula, 
each one of which is composed of numerous joints. These 
apparently spring from a dark spot in the centre, which is 
most probably the body of the animal, though I could not 
make out distinctly any particular organs belonging to it. In 
general, when under the microscope, there were to be seen a 
considerable number of very small round bodies (invisible to 
the naked eye), attached to the tentacula, or swimming round 
about them, and which I only saw in company with this ani- 
mal. ‘They were wheel-shaped, transparent, with a dark streak 
running through the centre, and possessed considerable celerity 
of motion, which was of two kinds, a circular motion upon their 
bases, and a rotatory motion upon their axes like that ofa wheel, 
the latter of which was perhaps the one most commonly used. 
Another body, which evidently belongs to the same family as 
the last, occurred also very frequently in company with it. 
Vou. III, — No. 14. Y¥ 
