and the tentacles. The tentacles are soft and waving, projected or drawn
in at will, and they retain their flexible character through life, and
decompose when the animal dies. For this reason the dried specimens of
Corals preserved in museums do not give us the least idea of the living
Corals, in which every one of the millions of beings composing such
a community is crowned by a waving wreath of white or green or
rose-colored tentacles.

As soon as the little Coral is fairly established and solidly attached
to the ground, it begins to bud. This may take place in a variety of
ways, dividing at the top or budding from the base or from the sides,
till the primitive animal is surrounded by a number of individuals like
itself, of which it forms the nucleus, and which now begin to bud in
their turn, each one surrounding itself with a numerous progeny, all
remaining, however, attached to the parent. Such a community increases
till its individuals are numbered by millions; and I have myself counted
no less than fourteen millions of individuals in a Coral mass measuring
not more than twelve feet in diameter. These are the so-called Coral
heads which form the foundation of a Coral wall, and their massive
character and regular form seem to be especially adapted to give a
strong, solid base to the whole structure. They are known in our
classifications as the Astraeans, so named on account of the star-shaped
form of the little pits that are crowded upon the surface, each one
marking the place of a single individual in such a community.

Thus firmly and strongly is the foundation of the reef laid by the
Astraeans; but we have seen that for their prosperous growth they
require a certain depth and pressure of water, and when they have
brought the wall so high that they have not more than six fathoms of
water above them, this kind of Coral ceases to grow. They have, however,