HOW SEA ANEMONES ARE FORMED
THE most beautiful of all the creatures which live in the sea are undoubtedly the Sea Anemones, which are just like living flowers of all sorts of lovely colours. But I do not know why they are called sea “anemones,” for they are much more like asters, or dahlias, or chrysanthemums.
These anemones are made in a very curious way. You will notice, as you look down into a rock-pool, that their soft fleshy arms, or “tentacles,” are all spread out like the petals of a flower. If you touch them, however, they at once come closing in and disappear, so that in two or three moments the creatures look like mere lumps of coloured jelly. But if you wait for a little while they will push out their tentacles again, and spread them just as before.
The fact is that the body of a sea anemone is a kind of double bag. Suppose you take a paper bag, twist up the mouth, and push it downwards, so that the sides of the bag surround it all the way round. You will then have two bags, as it were, one inside the other, the space between the two being filled with air. Now that is just the way in which the body of a sea anemone is formed, with this difference, that the space between the outer bag and the inner one is filled with water. It forms, in fact, a kind of water-jacket.
Next, remember that all those spreading tentacles are really tubes, like the fingers of a glove, closed at the top, but opening at the bottom into this water-jacket. And remember also that the outer walls of the body are formed of very strong muscles. So, you see, when the anemone wants to spread its tentacles, all that it has to do is to contract these muscles. The water is then squeezed up into the tube-like tentacles, which of course expand. When it wants to close them it relaxes the pressure, and the water flows out of the tubes again and back into the water-jacket, so that they all come folding in.
The lower part of an anemone’s body is called the “foot,” and is really a big and strong sucker, by means of which the animal clings so firmly to the surface of a rock or a stone that it almost seems to be growing out of it. But these creatures do not spend the whole of their lives without moving, as oysters and barnacles do. Sometimes they will creep slowly along over the surface of the rock, in order to find a more comfortable situation, or one where they will have a better chance of catching prey. And sometimes they will loose their hold of the rock altogether, rise to the surface of the water, turn upside down, and hollow their bodies in such a way that they form little boats, which can float along over the waves for quite a long distance.
PLATE XLI
THE SMOOTH ANEMONE (1)
This is by far the commonest of all the sea anemones, and you may find it in hundreds and thousands by going down among the rocks when the tide is out, and looking into the pools. You are almost sure to see that their rocky walls are dotted all over with lumps of brown or dark green jelly, some only about as big as peas and some as large as plums. These are Smooth Anemones, with their fleshy feelers, or “tentacles” closed. And just here and there you may see one of them open, and you will notice that all the way round the edge of its body, between the roots of the tentacles, it has a row of little bead-like objects of the most beautiful turquoise blue. For this reason the smooth anemone is sometimes known as the “beadlet.”
You can easily keep these anemones in captivity, for they are very hardy, and are no trouble at all to feed. Indeed, they will go without any food at all for three or four months together, and seem all the better for their long fast. But if you put a tiny dead crab, or a shrimp, or a sandhopper, into the midst of their spreading arms, you will see the tentacles close round it, and push it down into the mouth, which lies just in the very middle. For about forty-eight hours the animal will then remain closed up. But as soon as it has digested its dinner out will come the tentacles again, bringing with them the empty shell of the victim.
Every now and then, like other anemones, this animal changes its skin, and when it leaves its position on the side of a rock-pool and crawls to a new one, it nearly always leaves a cast skin behind it.
1. THE SMOOTH ANEMONE.2. THE DAISY ANEMONE.
PLATE XLI
THE DAISY ANEMONE (2)
This is not nearly such a common creature as the smooth anemone, but you may sometimes find it in the rock-pools at low-water on our southern and western coasts. It is pale greyish yellow in colour, and has an odd way of altering its shape from time to time, so that sometimes its body is long and slender, and sometimes it is short and stout, while the disc may be long and narrow one day, and almost round the next. You can always tell it at once, if you should happen to meet with it, by looking at its fleshy feelers, or tentacles, which are marked with rings of grey and white.
PLATE XLII
THE THICK-ARMED ANEMONE (1)
Where the coast is sandy and rocky too this anemone is often rather common. Yet very few people ever see it, because it nearly always fastens itself quite low down on the rocks which border the pools, so that at least half of its body soon becomes covered up with sand. Besides this, it has a great number of very tiny sucker-feet, not unlike those of the starfishes and the sea urchins, and with these it clings to tiny stones and bits of broken shell, which often quite conceal its upper surface, so that one really cannot see the anemone itself at all. But it is quite one of the very handsomest of all the British sea anemones, for when it is fully grown it is over five inches in width; and sometimes it is pearly white in colour, and sometimes it is green, and sometimes it is purple and brown, and sometimes it is crimson, while its tentacles are banded with scarlet and white. These tentacles are rather stout in proportion to their length, and when they are fully spread the animal looks very much like a cactus dahlia.
PLATE XLII
THE SNAKE-LOCKED ANEMONE (2)
This is also one of the prettiest of these very pretty creatures. But it is not in the least like the thick-armed anemone, for instead of having a broad, stout body it has a long slender one; and instead of short, thick tentacles, like the petals of a dahlia, it has a bunch of almost thread-like arms, which really rather remind one of little white snakes. And when they are spread these long arms are hardly ever still, but are always waving about in the water.
1. THE THICK-ARMED ANEMONE.2. THE SNAKE-LOCKED ANEMONE.
When the snake-locked anemone closes up, however, you would never know it for the same creature, for it not only draws its long tentacles back into its body and tucks them away out of sight, but contracts the body itself until it is almost flat. Unless you looked very carefully at the rock to which it was clinging you would never notice it at all.
This anemone is not a very common one, and is chiefly found on the rocky coasts of Devonshire and Cornwall. In colour it is almost white.
CHAPTER X
MADREPORES, CORALS, AND SPONGES
PLATE XLIII
MADREPORES (1)
IN some ways these curious creatures are very much like sea anemones, and if you were to find one with its tentacles spread you would be almost sure to think that it was a small anemone. But if you touched it you would find that you had made a mistake, for instead of closing itself up into an almost shapeless lump of jelly, as the anemones do, it would just draw back its tentacles, and leave a kind of flinty skeleton still standing up. For madrepores are really much more like the wonderful little creatures which make coral. They suck lime, in some strange manner which nobody quite understands, out of the sea-water, and build it up round and underneath their own bodies. And if you startle them in any way they draw themselves down inside this shelly covering, and disappear from sight altogether; so that all that you can see is a number of thin plates standing upright on their edges, and looking rather like the lower surface of a mushroom turned into stone.
Madrepores feed on very tiny animals, such as the fry of small fishes, and the zoeas of shrimps and prawns. And they catch their victims by means of a number of fleshy tentacles, which are very much like those of the sea anemones, except that they always have little round knobs at the tips. These tentacles are set with numbers of tiny cells containing slender poisoned darts, just as those of the anemones are.
If you want to find madrepores, you must look for them among the rocks near the water’s edge when the tide is at its lowest. But they are not very common, and on many parts of the coast they are never found at all.
PLATE XLIII
THE SEA FINGER (2)
If you walk along the shore as the tide goes out, you may often find a soft, pink, fleshy object which has been thrown up by the waves. And if you search among the pools at low-water, you are nearly sure to see other soft, pink, fleshy objects just like it growing upon their rocky sides, or upon the stones and shells which lie at the bottom. They are often known as “dead men’s fingers,” or “dead men’s toes.” But as those are not very nice names, we will call these objects “sea fingers.”
Now if you pick up one of these sea fingers and look at it carefully, you will see that its surface is pierced all over with numbers of tiny holes. And if you take a good strong magnifying-glass, and look at one of the holes through that, you will see that it is shaped like a little flower with eight petals, or a star with eight rays.
The fact is that the sea finger is the home of a most curious animal; or perhaps one should rather say that it is the home of hundreds of most curious animals. Indeed, it is not at all easy to know which is the right way to describe it. For if you were to take a living sea finger, and to put it into a vessel of clear sea-water, you would very soon notice that a little tiny star-shaped animal had poked itself out of each little star-shaped hole. There would be hundreds of these little animals—or “polyps,” as they are called—altogether. But yet they would only have one body between them, for they are joined together in such a wonderful way that the food which is caught and eaten by one polyp nourishes all the others as well as itself!
1. THE MADREPORE.2. THE SEA FINGER.
PLATE XLIV
THE TUFT CORAL (1)
Nearly all the coral-building animals are found in the tropical seas, for they can only live in water which is quite warm all the year round. But there are just a very few which are sometimes found off our own shores, and one of these is the Tuft Coral. It looks rather like a tree which has just been “pollarded” by having all the small branches taken away and all the big ones cut quite short; and sometimes it weighs as much as six or even seven pounds.
People sometimes say that the curious substance which we call “coral” is made by “coral insects.” But the little animals which make it are not related in any way to the true insects. They are really tiny polyps, very much like those of the sea finger; and they suck up lime out of the water, and build it up underneath and round their own bodies, just as the madrepores do.
If you were to place one of these tuft corals in a vessel of clear sea-water, and to watch it carefully, you would soon see the little polyps poking themselves out, and spreading their tiny fleshy feelers, or “tentacles.” The coral which they make is pearly white in colour, with just a faint tinge of rosy red, and the polyps themselves are partly white, and partly fawn, and partly chestnut brown.
One does not often find a tuft coral, however, for the polyps like to live in rather deep water. But when there is a very high spring-tide, as there generally is about the end of March and the end of September, the waves retreat afterwards a good deal farther than usual. And then, if you go right down to the water’s edge, you may perhaps find a tuft coral fastened to the rocks.
PLATE XLIV
THE BREAD-CRUMB SPONGE (2)
I dare say that you will be rather surprised to hear that nearly three hundred different kinds of sponges have been found in the British seas. You will not be able to find very many of these, however, for they nearly all live in deep water, and have to be scooped up by means of the dredge. But the Bread-crumb Sponge is easily found, for it lives in shallow water, and you are nearly sure to find it if you look for it in the rock-pools.
1. THE TUFT CORAL.2. THE BREAD-CRUMB SPONGE.
3. THE GRANTIA SPONGE.4. FORAMINIFERA.
But I hardly think that anybody, on seeing it for the first time, would take it to be a sponge at all. For it is not in the least like a bath sponge. It is just a kind of fleshy crust, sometimes greenish in colour and sometimes yellow, which grows round the stems of sea-weed, or covers the surfaces of rocks and stones. And the odd thing about it is that when it clings to sea-weeds its surface is quite smooth, with a number of large holes in it, but that when it grows on rocks it is covered all over with little projections which look just like the craters of volcanoes.
It is rather difficult to describe the animal which lives in the sponge, for it really consists of a large number of tiny animals all joined together in one common mass, very much like the polyps of the sea finger. But they are so very small that unless you examine them by means of a good strong microscope they only look like a mass of brownish jelly.
These little creatures obtain their food in a very curious way. If you look at the surface of the sponge through a magnifying-glass, you will see that it is pierced by a great many very tiny holes as well as by a number of bigger ones. Now water is always passing in through the small holes and out again through the big ones; and as it does so the little creatures manage to suck out all the tiny atoms of animal and vegetable matter which were floating about in it.
PLATE XLIV
THE GRANTIA SPONGE (3)
This is quite a small sponge, which you may often find by hunting about in the rock-pools just above low-water mark. Sometimes it clings to sea-weeds, and sometimes it hangs down from the surfaces of the rocks; and when you find one you are almost sure to find several others close by.
In appearance, they are rather like little flat white bags, or purses; and when they reach their full size they are generally about an inch long and an inch and a half wide.
PLATE XLIV
FORAMINIFERA (4)
“Foraminifera!” That is rather a long name; isn’t it? But if we cut it in two, and strike out one of the letters, we shall see what it means. Foramin-(i)-fera. Now the first part of the name is a Latin word which means “a hole,” and the last part is another Latin word which signifies “bearers.” So “foraminifera” means “hole-bearers,” and this title has been given to certain very tiny creatures which live in the sea because they inhabit shells, which are pierced all over by numbers and numbers of still tinier holes.
These foraminifera are so very small that numbers of them can live in a single drop of water! Yet, strange to say, all the chalk in the world is made of their shells! For in days of old—thousands and thousands of years ago—they were found in the sea in millions of millions of millions. And as they died their empty shells sank down to the bottom of the sea in such enormous numbers that at last they formed a layer hundreds of feet thick. Then suddenly one day there came a great earthquake, and a great deal of this vast layer of shells was forced up above the surface in the form of what we now call chalk. So that “the chalk cliffs of old England” are really made of nothing but shells, so very small indeed that you cannot see them without the help of a very strong microscope!
There are a great many different kinds of foraminifera. But if you look at them through a good microscope you will always see that their shells are pierced by the tiny holes from which they take their name.
CHAPTER XI
SEA-WEEDS
PLATE XLV
THE BLADDER-WRACK (1)
I DARE say that you would like to know something about the sea-weeds which you may find on the shore; so I am now going to describe some of those which you are almost certain to meet with.
First of all, then, and commonest of all, there is the bladder-wrack. Wherever there are rocks on which it can grow you will always see it in great masses. And after every storm enormous quantities of it are torn off and flung upon the beach. Then the farmers send down their carts to carry it away. For after it has been piled up in heaps for some time, so as to allow it partly to decay, it makes a most useful manure; and the farmers are only too glad to be able to spread it over their fields.
This plant is called the “bladder-wrack” because of the odd little oval bladders filled with air which are found in the leaves, and which explode with a slight report if you tread upon them or squeeze them.
1. THE BLADDER-WRACK.2. THE OAR WEED.
PLATE XLV
THE OAR WEED (2)
This is a very fine sea-weed indeed, for it often grows to a height of ten or eleven feet. But you are not likely to see it growing, for it lives in rather deep water, where it is always covered even at the lowest tides. It is often flung up by the waves, however, and you must many times have noticed its long, thick stem and flat plate-like leaves lying upon the shore as the tide was going down.
The stem of the oar weed is often used for making the handles of knives. When it is quite fresh, it is so soft that the “tang” of a knife-blade—the part, that is, which is fastened into the handle—can be forced into it quite easily. But if it is put aside for a few months to dry it becomes as hard and solid as horn, and holds the blade so firmly that it is almost impossible to pull it out again.
If you look at the “roots” of the oar weed you will see that they are not like those of plants which grow in the ground, but are really very strong suckers. For sea-weeds do not send their roots down into the rock, as land plants do into the ground, but merely cling to the surface. That is why they are so easily torn up by the waves.
PLATE XLVI
CORALLINE (1)
For a great many years naturalists could not make up their minds whether this very pretty sea-weed was really a sea-weed or not. For it possesses the curious power of sucking out lime from the sea-water and building it up round itself, just as the polyps of the madrepores and the corals do: so that when it dies and decays it leaves a kind of chalky skeleton behind it. For this reason it was often supposed to be really a kind of coral. We know now, however, that it is a plant. For if it is placed in acid, which dissolves away this “skeleton,” we find that a true vegetable framework is left behind it.
While it is alive the coralline is of a deep purple colour. It is quite a small plant, growing only to a height of four or five inches, and you may find it in quantities on the rocks near low-water mark.
PLATE XLVI
DULSE (2)
This weed is also known as the Dillisk, or Dillosk. I dare say that you have often seen it, for it is quite common on nearly all the rocky parts of our coasts, sometimes growing on the rocks themselves, and sometimes on the larger sea-weeds. In colour, it is a deep, dark red, and if you look down upon it on a bright sunny day, as it grows in a pool of clear sea-water, you may see all kinds of lovely rainbow tints playing over its leaves. The leaves or “fronds” as they are more properly called, are about two inches long and a quarter of an inch wide.
1. CORALLINE.2. DULSE.
The dulse is one of the sea-weeds which are used for food. On many parts of the coast of Ireland it is very largely eaten, both boiled and raw, and some people are so fond of it that they have it for breakfast every day.
PLATE XLVII
THE GREEN LAVER (1)
Another name for this plant is the Sea Lettuce; and certainly, with its broad, bright green, crinkled leaves, it does look rather like a cabbage lettuce. It is a very useful plant to keep in a salt-water aquarium, for its leaves give off little bubbles of oxygen gas, which help to keep the water pure and fit for fishes and other creatures to live in. If you look at it on a bright sunny day you will often find that the leaves are covered all over with these tiny bubbles, which look just like little drops of quicksilver.
The green laver is found in abundance on most of our rocky coasts, and is often boiled down into a kind of jelly and used as food.
PLATE XLVII
THE PURPLE LAVER (2)
This plant is very much like the green laver, except that it is purple in colour instead of green. It is often boiled down into jelly and used as food, more especially in Ireland, where it is generally known as “sloke,” and is cooked and brought to table in a silver saucepan.
PLATE XLVIII
CARRAGEEN MOSS (1)
I do not know why this plant should be called a moss, for it is not in the least like the true mosses, as you can easily see by looking at the illustration. It is very common indeed, growing both in the pools among the rocks and also in deep water. But it is not a very easy plant to describe, for it varies very much in colour, being sometimes green, and sometimes yellow, and sometimes purple. Like the dulse, it is often used for food, being boiled down into a kind of jelly, and then either eaten by itself, or mixed with tea or coffee. It makes very good size, too, and is used a good deal in the manufacture of calico. Farmers use it, too, for fattening calves, and also for mixing with the potatoes or meal with which the pigs are fed. So that altogether it is a very useful sea-weed indeed.
1. THE GREEN LAVER.2. THE PURPLE LAVER.
PLATE XLVIII
THE SEA GRASS (2)
This is a very pretty sea-weed, which you may often find growing in great quantities in the pools which are left among the rocks as the tide goes down. When its long, narrow fronds are waving to and fro in the water it really looks most lovely, and you can almost fancy that you are gazing down into fairyland. And as the shrimps and prawns and little fishes dart in and out among its bright green leaves, one might almost imagine them to be the fairies!
The fronds of this pretty sea-weed vary a good deal in width, for sometimes they are like strips of narrow ribbon, and sometimes they are scarcely broader than hairs.
PLATE XLVIII
THE GRASS WRACK (3)
In one way this is the most curious of all the plants which you may find on the shore. For it is not really a sea-weed at all, but is a flowering plant which somehow or other has taken to living at the bottom of the sea. You may often find it in the deeper pools just above low-water mark; and you can tell it at once by its very long, very narrow, bright green leaves. These leaves are often three or four feet in length, while they are only about three-eighths of an inch wide; so that really they do look very much like blades of grass.
The grass wrack is not one of the true grasses, however, for it has real flowers, which grow in a kind of sheath formed by one of the shorter leaves. And its stem creeps along under the muddy sand, and throws up leaves at intervals, very much like that of the common bracken. On many parts of the coast it grows in the greatest abundance. There are large fields of it, so to speak, below low-water mark, which afford refuge for all kinds of small sea-creatures. Indeed, if you want to catch these animals for yourself, the very best way to do it is to wait until the tide is quite low, and then to wade into the water and fish about in the masses of grass wrack with a small net.
1. CARRAGEEN MOSS.2. THE SEA GRASS.
3. THE GRASS WRACK.
Great quantities of the long, narrow leaves of this plant are often flung up on the shore; and when they have been thoroughly dried they are often used for packing glass or china, instead of hay or straw.
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