ives of those early Corals called by naturalists Tabulata and
Rugosa,--distinguished from the Polyp Corals by the horizontal floors,
waving in some, straight in others, which divide the body transversely
at successive heights through its whole length, and also by the absence
of the vertical partitions, extending from top to bottom of each animal,
so characteristic of the true Polyps. As I have said, they were for a
long time supposed, notwithstanding these differences, to be Polyps, and
I had shared in this opinion, till, during the winter of 1857, while
pursuing my investigations on the Coral Reefs of Florida, one of these
Millepores revealed itself to me in its true character of Acaleph. It is
by its soft parts alone--those parts which are seen only in its living
state, and when the animal is fully open--that its Acalephian character
can be perceived, and this accounts for its being so long accepted as
a Polyp, when studied in the dry Coral stock. Nothing could exceed
my astonishment when for the first time I saw such an animal fully
expanded, and found it to be a true Acaleph. It is exceedingly difficult
to obtain a view of them in this state, for, at any approach, they draw
themselves in, and remain closed to all investigation. Only once, for a
short hour, I had this opportunity; during that time one of these little
creatures revealed to me its whole structure, as if to tell me, once for
all, the story of its existence through all the successive epochs from
the dawn of Creation till now, and then withdrew. With my most patient
watching, I have never been able to see one of them open again. But to
establish the fact that one of the Corals represented from the earliest
period till now, and indeed far more numerous in the beginning than any
other, was in truth no Polyp, but an Acaleph, the glimpse I had was
all-sufficient. It came out as if to bear witness of its class,--as if
to say, "We, too, were among the hosts of living beings with which God
first peopled His earth."

With these branching Corals the reef reaches the level of high-water,
beyond which, as I have said, there can be no further growth, for want
of the action of the fresh sea-water. This dependence upon the vivifying
influence of the sea accounts for one unfailing feature in the Coral
walls. They are always abrupt and steep on the seaward side, but have a
gentle slope towards the land. This is accounted for by the circumstance
that the Corals on the oute