Back Aa

Within the Deep

Close

<h4>LESSON XI</h4> <h3>THE GARDEN OF THE SEA</h3> For many centuries men were puzzled over those strange growths in the sea--Corals and Sponges. Were they to be classed as animals or as vegetables? It was by no means an easy question to answer. Corals, with their pretty colour, and their stems and branches growing up from the sea-bed, were said to be shrubs, but they were as hard as rock, said some people, so how could they be vegetables? The reply to this was, that the Coral became hard as soon as it reached the air. Then, of course, it was found that Coral was as hard under water as above it, and the question was still unanswered. Sponges, too, were thought to be sea-plants for many, many years; though some people even said that they must really be made of hardened sea-foam! The Sponge took its place in the vegetable kingdom, then it was moved to the animal kingdom, and back again. This went on for long years. Then, by careful watching, it was found that the Sponge is an animal. True, it is a very lowly member of the great kingdom of animals, yet it is one, and not a plant. <center> <ANTIMG alt="[Illustration: CUPS AND SOLID SPONGES]" src="images/img22.jpg"></center> Like all other animals, the Sponge animal must eat, and its way of doing so is rather strange. If you look at any ordinary washing-sponge, you notice a great many very small openings and some larger ones amongst them. It is through the smaller holes, or pores, that the Sponge gets its supply of food. When it is alive, and in its own home, there is a current of water always passing through its and the Sponge depends on the food which the water brings. Now, if you could watch this water-current, you would see that it rushes into some of the holes, and out of others; it has a certain path to follow. It enters the small pores, or openings, of the Sponge, and goes along narrow canals, and is then led into larger ones. Finally, it rushes out again through those large openings we noticed. We may compare it with traffic coming into a city by many narrow streets, then passing into broader roads, and at last out again by big main roads. <ANTIMG align="right" alt="[Illustration: Photo: A. F. Dauncey. SEA FURZE]" src="images/img23.jpg"> How does the Sponge animal cause this current; and how is it made to follow a certain path? The narrow canals in the Sponge are lined with lashes, or tiny hairs, so very small that you can just see them through a microscope. Now the secret of the wonderful water-current is a secret no longer. As long as the Sponge lives, these little lashes are always moving, always lashing the water along in one direction. They cause it to follow its proper course, through and through the Sponge, and out again into the sea. On its way it loses the tiny scraps of food which it contains, and carries away any waste stuff out of the Sponge. You will have noticed that there are various kinds of Sponges in the market; some are large and flat, others small and cup-shaped; some are soft, and others rather hard. They are all somewhat horny and elastic. This "spongy" material is the skeleton of the Sponge animal, cleaned and dried for your use. Some kinds of Sponge would tear your skin if you tried to use them, for they have a hard skeleton. It is made of lime, and sometimes of flint, which the Sponge obtains from its food. Of course we use only those sponge-skeletons which are soft; but the cheaper kinds do often contain little flinty needles. The best washing-sponges live in warm seas, attached to the rocks on the sea-bed. Divers go down and obtain them; or else they are dredged up, cleaned, dried, and sorted, and then sent to the market. Some Sponges, called Slime Sponges, have no skeleton, being merely a living mass of slime. Coral is also the hard skeleton of a little animal, known as the Coral Polyp. The rest of the polyp's body is soft jelly, which many fish regard as good food. The Sea Anemone--another jelly-animal--is first cousin to the Coral Polyp. And we may call the Jellyfish second cousin to these two, for it is in the same big division of the animal kingdom. The pretty red Coral, then, is really the hard part of a little jelly-animal. This animal is much like a Sea-anemone, with a hard skeleton of lime. Coral, as you know, looks like a solid rock; it is really made of needles of lime, fastened together into a solid mass by the little Coral Polyp. Now, many of the Coral animals have the strange habit of budding. The buds become perfect polyps, and then they, too, begin to bud. In this way, those marvellous coral-reefs and coral-islands have been made. Branch by branch, layer by layer, the hard Coral is built up by myriads of the small, soft-bodied creatures. This kind of polyp can live only in warm, clear water. So it is not found in the cold depths of the sea, nor in the seas near our islands, but in the warm shallow waters near tropical lands it flourishes so well that it builds up most wonderful Coral walls. So strong are they that they can defy the terrific force of the waves. <center> <ANTIMG alt="[Illustration: THE PICTURE STORY OF A CORAL ISLAND.]" src="images/img24.jpg"></center> Some coral-reefs are of immense size and strength. One, near the coast of Australia, is nearly a thousand miles in length. These marvellous works of the polyp are of great use, for they break the force of the waves, and so make a calm shelter for vessels. The brilliant masses of Coral make a world of colour in the clear seas of the tropics, a gay garden inhabited by fishes of gaudy hues. In dull seas we have, as a rule, dull creatures to match. And in bright, warm, sunny seas the fishes are also brightly coloured. A dull fish would show up amid such rich colours, so it is easy to know why Coral fish wear such fine clothes. Many of them spend all their time among the Coral, their food being the living tips of the Coral "branches," which they nip off with fine, sharp teeth. Others have teeth like millstones, fit for crushing the hard Coral, and eating the fleshy body of the polyp within. Blue, red and yellow, striped and spotted, and of wonderful shapes, are the fish which swim in these coloured gardens of the sea. Some of them have golden bands round their bodies, and fine spines which wave in the water like shreds of weed--all to help them hide in the bright, sunlit groves of Coral. Gorgeous Sea-anemones of all shapes and sizes add to the brightness; and even the Shrimps, Prawns, and Crabs are coloured to fit their background. Crabs are always surprising us with their queer ways and quaint "dresses"; and here, among the Coral, it is the same story. For there are Crabs whose shelly coats are covered with coloured knobs and spikes, so that the sharpest eye cannot pick them out from the Corals on which they rest. <h4>EXERCISES</h4> 1. How does the Sponge obtain its food? 2. What is Coral? 3. How are Coral-reefs formed? 4. Why are there no Coral-reefs in our seas? <div style="break-after:column;"></div>

1 of 2

2 of 2