polypes

In the red coral, the skeleton belongs to the whole; in the white coral there is a special skeleton for every one of these polypes in addition to that for the whole body.

Essays 2007

The second point to deal with was — if the polypes cannot have built there while the level of the sea has remained stationary, then one of two things must have happened — either the sea has gone up, or the land has gone down.

Essays 2007

But this is by no means the case in the sea anemone, because when digestive difficulties of this kind arise he gets out of them by splitting himself in two; and then each half builds itself up into a fresh creature, and you have two polypes where there was previously one, and the bone which stuck in the way lying between them!

Essays 2007

Having understood thus far the general nature of these polypes, which are the fabricators both of the red and white coral, let us consider a little more particularly how the skeletons of the red coral and of the white coral are formed.

Essays 2007

I told you that the polypes which built these reefs were not able to live at a greater depth than 20 to 25 fathoms of water; and that is the reason why the fringing reef goes no farther from the land than it does.

Essays 2007

They differ from the ordinary polypes just in the same way as those plants which form a peat-bog or meadow-turf differ from ordinary plants.

Essays 2007

Now let the coral polypes come and perch on the shore and build a fringing reef, which will stop when they come to 20 or 25 fathoms, and you will have a fringing reef like that round the island in the illustration.

Essays 2007

The red coral is comparatively limited, but the polypes which form the white coral are widely scattered.

Essays 2007

They are the coral polypes which grow, flourish, and add to the mass of calcareous matter which already forms the reef.

Essays 2007

The fringing reef would be carried down also; but we suppose that the sinking is so slow that the coral polypes are able to grow up as fast as the land is carried down; consequently they will add layer upon layer until they form a deep cup, because the inner part of the reef grows much more slowly than the outer part.

Essays 2007