When we were sailing through the Pacific Ocean, I saw a great many coral reefs and islands; and perhaps there is hardly one of the wonderful things which I have seen in my travels, that I remember with more pleasure, or love more to think about, so I shall be glad to tell you all I know of them. You are acquainted with the appearance of Coral, as you have often seen pieces of it in cabinets, and employed as ornaments; and you therefore know that it always abounds with little holes, but its form, and the shape of these holes, vary considerably. Some of it occurs in branches, like the branches of trees, and in consequence Sometimes it is in large roundish masses, called brain stones, from its resemblance to the brain of an animal; the openings are then long holes placed in two rows between high ridges, like this. And a third form is found consisting of thin pieces, thinner than writing paper, placed on edge, spreading out from a centre, or from a line There is also the precious red Coral of which beads and other trinkets are made, found principally in the Mediterranean Sea, and several other sorts, more or less rare. But what I have described to you are the commonest. This curious substance extends over hundreds of miles in various parts of the Tropical Seas, in islands of different forms. But before I describe these to you, I must tell you what is known respecting the little animals by which it is manufactured, for it is proved to be the work of certain kinds of the little creatures called Polypes. THE CORAL-MAKING POLYPES. The Polypes are a kind of animals apparently of very simple structure, without bones, or shells, or heads, or brains. They have very large mouths surrounded by a great number of tentacula, or feelers, which are threads of flesh possessing the sense of touch in great perfection; and to these tentacula they owe the name Polypes, which comes from two Greek words signifying many feet. The ancient naturalists who named them, I suppose did not know but that they were feet. ACTINIÆ CORAL BUILDERS If this was the case, they were not, however, quite right. Most kinds of Polypes very seldom move from one place to another in any way, but stick themselves upon a rock by means of the flat part of their bodies, and there remain; and when they let go they generally suffer themselves to be washed by the waves to some other place, where they can conveniently fix again. If you have ever been at Brighton, or at any other places by the sea side, for any length of time, I dare say you have seen the sea anemones, or sea flowers, as they are called, carried round by the fish people to show to their customers; or possibly you may have seen them in the holes on the rocks. They are proper Polypes, and the scientific name of them is ActiniÆ. As they lead their lazy lives as if they were rooted in the rock, when they are hungry they spread out their tentacula to catch any little insects or minute fish, such as crabs and shrimps, which may come in their way. The instant they feel anything, they close in all their tentacula with surprising force. It is worth while to put one's finger just in the centre of one of these "flowers," to feel how strongly they can draw anything in. I have seen one suck in a little crab half as large as its own body, in this manner. When closed up they look an insensible lump of pulpy flesh, but when their fringe of tentacula If one of these curious creatures is cut into several pieces in certain directions, each piece will become an animal. You will say that this seems more like a plant which is propagated by cuttings, than a proper animal. But for all this, and although it only appears to possess the same sort of sensibility, in regard to light and touch, as some plants do, I can give you a very good reason for its being considered as an animal,—it can move itself according to its own will, and in choosing the time in which it moves, it exhibits instinctive intelligence. When it finds its little inch of rock in any respect inconvenient from its being too high above low water mark, or not sufficiently in the way of the little creatures on which it wants to satisfy its appetite, it sucks in a great quantity of water, and swells itself out so as to become nearly as light as the water, Now the coral builders are all of the same general character as the ActiniÆ, in the construction of their bodies, their various colours, great mouths surrounded by feelers, and habits of taking their meals. But besides their being such wonderful architects, they differ from the English creature in being very sociable, and living together in immense companies. When you read of the Pyramids of Egypt, or of any other great structures, you may justly think them wonderful proofs of what the labours of many men may do when directed to a single object; but here you have not houses, pyramids, cities, nor even mere islands, but whole continents constructed by the combined labours of little insects. I cannot tell you, neither can any one else, in what manner these little workmen perform their In fig. 2 of the plate, you may see some of these animals showing their rich rosettes on a piece of branch coral, such as is represented in the first wood cut, page 204. There is another sort of branch coral, where the animal always lives at the end of the branch, the whole of which it has to itself, and will then spread out its tentacula in a star on the extremity, as you may see in figs. 3 and 4. In fig. 5, you may see one of the animals which construct the sort of coral represented in the cut, page 205. Since these little creatures can lay down their tentacula in the openings of their stony houses, when they are not hungry, or when they are alarmed by the approach of anything that would hurt them, they do not want the tough skin with which the Actinia is covered, but have bodies of a very soft and yielding texture. FORMS OF THE CORAL REEFS. As I have now introduced to you, as well as I can by means of description and pictures, the inhabitants of these wonderful submarine continents, I shall now tell you something of the form in which they arrange their habitations. Those that I saw about the Society and Friendly Islands, were mostly in three different conditions. One kind forms a nearly circular reef, sometimes with an opening in it. It is a part of the common design of the Polypes always to make this opening on the Leeward side, when the place is one in which any particular wind blows during a great part of the year. I cannot tell you why Another sort have an island of which the foundation is coral, in the middle of a ring like the above; and a third sort are merely the same kind of rings round large islands, composed of other sorts of rocks and earth. A very great number of the islands hereabouts,—perhaps most of them, are surrounded in this manner. I well remember the first impressions which the sight of a coral reef made upon me. I always like to treasure up in my mind the first impression produced by a beautiful scene; for however wonderful the objects may be, when you have seen them many times, you become in some degree indifferent to them. This first impression that I am going to describe to you, is a continual feast to me when I think upon it, and I wish you could enjoy it with me. The first parts of the reef we saw were black, roundish masses, standing up out of the water, having just the appearance of black men's heads, and when I asked the sailors what they were, they told me they were "negroes' heads." I was curious, as you may suppose, to know what they could be, and I afterwards found they were masses of coral, which were not covered by the sea, except at very high tides, and had become blackened by the weather. The sun was shining brightly, and there was a smart breeze. The waves breaking over the No flower garden was ever more exquisitely varied, both as to form and colour, than the scene under the water. The coral itself, standing up in the forms of shrubs, wheat-sheaves, mushrooms, stags'-horns, cabbages, and cauliflowers, was mostly covered with millions of the little polypes, displaying their graceful rosettes of green, purple, yellow, brown and white. Among these were strewn innumerable shells from the smallest to the largest, Then there were seen fish darting in and out as they "With quick glance, Showed to the Sun their waved coats dropt with gold," the variegated Zebra fish, and a hundred other species, often popping up from deep holes and caves, of which we could not see the bottom. All seemed life, beauty, and enjoyment, and when I had looked at it a long time, it brought to my mind the time when God looked upon what he had formed, and said that it was good, for you could not wish anything to be different from what it was; the scene appeared faultless, and quite filled up the heart with emotions of love and beauty. This reef was one of those which surrounded a good-sized island. The cut will show you nearly how it appeared to be situated in regard to the land; a is the land; b the coral; and c There were in it several masses of coral of a very curious shape, such as I have since found always exist in Lagoons. They are first built up in the form of a sugar-loaf, and when they get up somewhere between high and low-water-mark, the polypes extend them at the sides so as to make a sort of mushroom top, closely resembling the stones which farmers place ricks upon, to keep them out of the way of rats and mice. Their constructing these rocks in the sugar-loaf form, so as to make them as firm as possible, is a proof that the labours of the As the tide went down, a considerable space of the shore of the reef was left dry, towards the Lagoon, where it slanted off gently. Upon this there were some of the large clam shells, such as you saw a cut of just now. They generally lay about half open, but they would occasionally shut their shells together with a loud report, and then spout up a stream of water three or four feet high. We boiled one of these fish and tasted it, but found it very disagreeable. The fish weighed about four pounds, and the shell about fifty. There were many of a much larger size. The reefs towards the sea outside the Lagoons go down very suddenly, and the soundings are generally deep, close alongside them. This is The surface of the reef is seldom quite so high as high-water-mark; but they sometimes go along an incredible distance without interruption, very near that point. The inhabitants of the group of islands called Disappointment Islands, and also of those called Duff's Islands, pay visits to each other over a bridge of coral 600 miles in length, on a great part of which their feet are close to the water, so that they look when on their journey at the time of high-water, just like troops marching on the surface of the ocean. The natives of some of the Polynesian islands have actually employed some of these wonderful little masons to build quays and piers. The way they do this, is to break off large masses of coral from any reef that may be near, and drop them down where they want to form the pier. In a short time the polypes will have stuck them There were once coral islands where England is now, for in many counties fossil coral is found in great quantities. It is indeed most likely that there are large tracts in every part of the world, which owe their existence to the labours of polypes. This would most probably be the history of the formation of one of these tracts, if it were in the Pacific Ocean. A volcanic eruption would throw up a mountain from the bottom of the sea, the top of which might be 60 or 70 feet below the surface. As soon as the eruption had ceased, some polypes who may have left their position on a neighbouring reef, might be brought by the tide into contact with the summit, and would immediately begin to work. The race of polypes would multiply, and the building would go on year after year, till the reef reached the surface. If you are fond of poetry, you would be much pleased with a very beautiful description of such a process as this, in James Montgomery's poem, called the Pelican Island, which you should read. |
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