The light of this creature, which is very brilliant, appears to issue
from every part of the body; but in another crustaceous animal, found
by Captain Tuckey, in the Gulf of Guinea, the luminous property resided
in the brain, which, when the animal was at rest, resembled a most
brilliant amethyst, about the size of a large pinhead; from this there
started, when it moved, flashes of a brilliant silvery light.