ay, they can eat with greater facility than their
sisters fixed on the rocks; for they do not have to wait, as the others
must, until food drifts casually to their tentacles. Besides this,
there is always floating on top some of the remains of the booty that
the crafty crab in his wandering impunity has gathered below.

Ferragut, on passing from one tank to the other, mentally established
the gradation of the fauna from the primitive protoplast to the perfect
organism.

The sponges of the Mediterranean swam as soon as they were born, when
they were like pin-heads, with vibratory movements. Then they remained
immovable, the water filtering through the cracks and crannies of their
texture, protecting their delicate flesh with a bristling of
spikes,--sharp limestone needles with which they pierced the passing
fishes and rendered them immovable, availing themselves of the
nourishment of their putrefying remains.

The nettles of the sea spread out their stinging threads by the
thousands, discharging a venom that stupefies the victim and makes him
fall into their corolla. With unlimited voracity, and fastened to the
rocks, they overpower fish much larger than they, and at the first hint
of danger shrink together in such a way that it is very difficult to
see them. The sea-plumes lie flabby and dark as dead animals, until
absorbing water, they suddenly rear themselves up, transparent and full
of leaves. Thus they go from one side to the other, with the lightness
of a feather, or, burrowing in the sand, send forth a phosphoric glow.
The belles of the sea, the elegant Medusae, open out the floating
circle of their fragile beauty. They are transparent fungi, open
umbrellas of glass that advance by means of their contractions. From
the inner center of their dome hangs a tube equally transparent and
gelatinous,--the mouth of the animal. Long filaments depend from the
edges of their circular forms, sensitive tentacles that at the same
time maintain their floating equilibrium.

These fragile beings, that appear to belong to an enchanted fauna,
white as rock crystal with soft borders of rose color or violet, sting
like nettles and defend themselves by their fiery touch. Some subtle
and colorless parasols were living here in the tank under the
protection of a second enclosure of crystal, and their mucous mistiness
scarcely showed itself within this bell-shaped glass except as a pale
line of blue vapor.

Below these transparent an