succession not otherwise observable. A Salpa, as one
of them is called, bears a marked resemblance to
its parent or offspring two generations off, but
never bears any resemblance to its own
immediate parent or young. This singular and
puzzling but well ascertained condition,
extends to many animals, chiefly of low organisation.

Star-fishes, sea-urchins, and such-like
creatures, are essentially marine. They owe their
name to their divergent rays, covered often with
spines and suckers, and they are exceedingly
remarkable for their habits as well as their form.
Such animals have lived during all time, and
present many curious varieties of structure. Some
are provided with stony plates fitting together
and forming a defence; in ancient times these
stony creatures were wonderfully varied and very
common. The lily-stars, as some of them are
called, are now nearly extinct.

There is a kind of snake-like star-fish very
widely extended, and not very uncommon in our
own seas, in which the long rays diverge from
a compact centre, and twine themselves round
any object with which they come in contact.
Can the reader imagine the astonishment and
delight of Dr. Wallick, the naturalist on board
H.M.S. Bulldog, recently employed in sounding
the ocean from Greenland to Labrador, when he
saw clinging on "like grim death" to the lower
extremity of a line that was being drawn up from an
Atlantic depth of some fifteen hundred fathoms,
an Ophiocoma, or brittle-star of this kind, living
still after the removal of the enormous pressure
of water under which it had hitherto existed,
and retaining the arms which in ordinary
cases it throws off with singular facility when
alarmed!

This, and a number of companion specimens
brought up at the same time with the mud from
the bottom, were of no microscopic size, each
of the arms being between two and three inches
long.

Thus, it is certain that these vast depths are
not untenanted, and that the presumed impossibility
of animals living without light and air at
depths so enormous that the mere pressure of
the water is equivalent to upwards of two tons
on every square inch of surface, is another of
those assumptions that we are all too ready to
make, and another proof that what is quite
contrary to our experience and utterly opposed to
any analogies we can draw, may still exist and
belong to the usual order of nature. Many of
these little star-fishes having been brought home,
they remain to be their own witnesses, and they
differ so little in appearance from some common
kinds, that an ordinary observer would pass
them by, little aware of the fact of their having
lived under circumstances, to us so utterly
inconceivable.

A singular class of marine animals have
recently attracted much attention, and are now to
be met with in most drawing-rooms. Some of
these, indeed (the Acalephæ, or sea-nettles),
inhabit the open ocean, and, being of large size,
are not imprisoned in our marine vivaria; but
others (true polyps) are among the chief
ornaments of those interesting contrivances. The
Medusæ, or jelly-fish, are sometimes two or three
feet across, or even more, and when removed
from the water, look like huge masses of nearly
transparent mucus which, if left alone, soon
evaporates, hardly leaving behind a few grains of
solid matter. Others are far smaller and
exquisitely beautiful; others again sting like nettles;
and many of them are concerned in producing
that marvellously beautiful phosphorescence of
the sea, which occasionally ranges for vast
distances. These animals serve to feed the
whales as well as to light up the ocean, and in
their young state they form exquisite little
groups of individuals of the most fantastic
shapes, formerly supposed to be polyps.

The sea anemones and polyps generally
consist of a cylindrical cavity opening above in a
wide mouth, round which are arranged numerous
feelers which the animal extends in search of
food. Some of them secrete no hard stony
matter, but others form those constructions
known in all seas to a greater or less extent,
and recognised as corals. Their variety is
endless, and the mass of solid matter thus
accumulated almost beyond belief. Separated
incessantly from sea-water, which reabsorbs it
again as readily from every limestone rock with
which it comes in contact, the mass of calcareous
matter enclosed by these singular animals is
constantly receiving additions, and, being little
subject to change, remains from one generation
to another accumulating into masses which form
a sensible proportion of the earth's superficial
crust. Since, however, the animals constructing
the large masses of coral which form islands in
the Pacific Ocean can only continue their labours
within moderate limits of depth, it would follow
that the mass of limestone is only a superficial
plate, were it not that in many cases the districts
thus built upon are, for some reason, constantly
descending below the level of the sea, while
some other tracts of land and sea-bottom are
known to rise and swell slowly upwards. The
descending land, when occupied by the coral
animal, is constantly supplied with additions
near the surface, and thus forms a vast
perpendicular wall to the depth of hundreds of
fathoms.

The beautiful red coral of the Mediterranean,
fished up from moderate depths every
year, is not of this kind. Like the other
branching varieties, it does not form compact
masses.

There yet remains one, and that not an
unimportant group of animals, that may fitly take
rank as contributing to the wonders of the
sea—the constructors of minute, many-chambered
shells. Such animals are mere lumps
of jelly, capable of extending themselves in all
directions, and capable also of forming shelly
coverings singularly elegant and complicated,
but so small that their shape can only be
recognised under a powerful microscope.
Multitudes of individuals, however, combine to
produce even a single shell, and thus the individual