like
living ribbons, some with thousands of coloured eyes, and Medusae like
living glass of the richest and softest hues, or glittering in the
sunshine with all the colours of the rainbow.

And on calm, cool nights how often have I stood on the deck of a ship
watching with wonder and awe the stars overhead, and the sea-fire below,
especially in the foaming, silvery wake of the vessel, where often
suddenly appear globes of soft and lambent light, given out perhaps
from the surface of some large Medusa.

"A beautiful white cloud of foam," says Coleridge, "at momently
intervals coursed by the side of the vessel with a roar, and little
stars of flame danced and sparkled and went out in it; and every now and
then light detachments of this white cloud-like foam darted off from the
vessel's side, each with its own small constellation, over the sea, and
scoured out of sight like a Tartar troop over a wilderness."

Fish also are sometimes luminous. The Sun-fish has been seen to glow
like a white-hot cannon-ball, and in one species of Shark (Squalus
fulgens) the whole surface sometimes gives out a greenish lurid light
which makes it a most ghastly object, like some great ravenous spectre.

THE OCEAN DEPTHS

The Land bears a rich harvest of life, but only at the surface. The
Ocean, on the contrary, though more richly peopled in its upper layers,
which swarm with such innumerable multitudes of living creatures that
they are, so to say, almost themselves alive--teems throughout with
living beings.

The deepest abysses have a fauna of their own, which makes up for the
comparative scantiness of its numbers, by the peculiarity and interest
of their forms and organisation. The middle waters are the home of
various Fishes, Medusae, and animalcules, while the upper layers swarm
with an inexhaustible variety of living creatures.

It used to be supposed that the depths of the Ocean were destitute of
animal life, but recent researches, and especially those made during our
great national expedition in the "Challenger," have shown that this is
not the case, but that the Ocean depths have a wonderful and peculiar
life of their own. Fish have been dredged up even from a depth of 2750
fathoms.

The conditions of life in the Ocean depths are very peculiar. The light
of the sun cannot penetrate beyond about two hundred fathoms; deeper
than this complete darkness prevails. Hence in many species the eyes
have more or less completely disap