STARFISHES’ LEGS
OF course you know starfishes very well indeed by sight, for they are flung up in numbers on the beach by almost every tide. But I wonder if you know where their legs are!
Perhaps you did not know that they have any legs. But they have hundreds and hundreds of them. Only, instead of keeping their legs outside their bodies, as we keep ours, starfishes always keep them inside, and poke them out through little holes in the skin when they are required for use.
If you want to see the legs of a starfish, you can very easily do so. First of all, you must catch a starfish, and make quite sure that he is alive. You can easily find out that by picking him up. If his rays are quite limp and flabby, and hang downwards from the disc, or middle part of his body, so that they look rather like the legs of a table, he is dead, and you can throw him away. But if they stand out stiffly he is alive. Then just put him into a pool of sea-water, and wait. After a few minutes you are almost sure to see that he is moving. Very slowly he begins to glide along the bottom of the pool. If he comes to a stone, he glides over it. If he comes to a rock, he glides up it. Then, if you suddenly snatch him out of the water, and turn him upside down, you will see his legs—little white fleshy objects waving about all over the lower surface of his body. And if you look at them through a good strong magnifying-glass, you will see that each one has a kind of little cup at the end of a slender stem.
Now this cup is really a sucker, very much like the suckers of a cuttle, only of course a great deal smaller. And the starfish walks by pushing one or two of its rays forward, taking hold of the ground with the suckers underneath them, and then pulling up the hinder rays and taking hold with the suckers underneath those, and so on over and over again.
PLATE XXXV
THE FIVE-FINGER STARFISH (1)
This is by far the commonest of all the starfishes. You can seldom walk for even a short distance along the shore without seeing it. And no doubt you might think that it must be a very harmless creature indeed, for it does not look as if it could injure any other animal in any way at all. Yet it is really a creature of prey, and feeds upon shell-bearing molluscs, such as small bivalves, which it always swallows whole. Then, when it has digested their bodies, it returns their empty shells through its mouth. And it can even eat such big creatures as mussels and oysters. Indeed, starfishes are the very worst enemies of the oyster-beds, and in one fishery alone, on the coast of North America, they are said to destroy more than ten thousand pounds’ worth of oysters every year!
1. THE FIVE-FINGERED STARFISH.2. THE BIRD’S-FOOT STARFISH.
A very strange fact about the starfish is that if one of its rays is cut off, a new one very soon grows in its place. Stranger still, if one of these creatures is cut in two, each half begins to throw out new rays, and in a few weeks’ time there are two starfishes instead of only one! That seems impossible; doesn’t it? But yet it is perfectly true.
And another very curious fact about starfishes is that they keep their eyes in very odd places—at the very tips of the rays. And in some starfishes these eyes are furnished with lids, which can be opened and shut!
PLATE XXXV
THE BIRD’S-FOOT STARFISH (2)
This is a very curious starfish, and a very handsome one as well. It is curious, because its five rays are all joined together by membrane, very much like the toes on a duck’s foot. That is why it is called the “bird’s-foot” starfish. And it is handsome, because it has a scarlet centre, a scarlet line all round the margin, and another one down the inner margin of each ray, all the rest of the body being bright orange.
The bird’s-foot starfish is not very often seen, for it lives some little way below low-water mark. But sometimes, when there has been a violent storm at a season of spring-tide—and you will remember that spring-tides come whenever there is a new moon or a full moon—it is flung upon the beach by the retreating waves, and you may find it lying on the sand when the tide is out.
PLATE XXXVI
THE SUN STARFISH
Sometimes you may find a very much larger and handsomer starfish lying upon the shore. It has twelve rays instead of five, and is often as much as eight or ten inches across. In fact, it looks very much like a big sunflower. Generally it is bright scarlet in colour, but just now and then one finds a sun starfish with a violet tinge; and sometimes, while the middle part of the body is vermilion red, the rays are pale rose-colour, or even pink.
THE SUN STARFISH.
Like most of the starfishes, this animal has a very curious way of protecting its eggs for some little time after they are laid. It heaps them all up together into a pile, and then bends its rays downwards in such a way that it stands upon their tips, looking just like a little table with twelve very stout legs! It turns itself into a sort of cage, in fact, with the eggs inside it, and so guards them carefully until they hatch.
PLATE XXXVII
THE BRITTLE STARFISH
The Brittle Starfish is certainly the very oddest of all odd creatures, for it not only grows new rays if the old ones should be torn off, but actually breaks itself into pieces if it is startled or alarmed! And it is such a timid animal that a slight touch, or even a shadow suddenly falling upon it, will alarm it! Then it gives a kind of shudder, and shatters itself into little bits, nothing being left but the central disc and a heap of fragments! However, it does not appear to suffer any pain, or to lose any blood, and the five wounds on the disc very quickly heal. Then after a few days five little buds begin to show themselves, which quickly grow into new rays, and in a few weeks’ time the brittle starfish is as perfect as ever!
So ready are these creatures to break themselves up, that it is most difficult to obtain a perfect brittle starfish for a museum.
Brittle starfishes are very active animals, and when they are alive their long slender rays are always wriggling and coiling and twisting about, hardly ever seeming to be still for a single moment. Indeed, one naturalist compares a brittle starfish to five very long and active centipedes stitched to a tiny pin-cushion!
There are several different kinds of these very curious animals, most of which live at some little distance below low-water mark, and are hardly ever caught except by means of the dredge. But sometimes you may find one of them lying on the sand at the bottom of a pool among the rocks.
THE BRITTLE STARFISH.
PLATE XXXVIII
THE SEA URCHIN (1 and 2)
The “urchin,” as of course you know, is a common country name for the hedgehog; and the Sea Urchin is so called because it is covered all over with long spikes, just as a hedgehog is. These spines, however, are very easily broken off, and when the animal dies, and its empty shell is tossed to and fro by the waves, they are knocked off in a very short time; so that when you meet with a sea urchin’s shell lying upon the shore you nearly always find that it is covered with nothing more than hundreds of very tiny pimples.
Now it is upon these little pimples that the spines grow. If you were to examine one of the spines with a magnifying-glass you would find that its base was hollow. This hollow base is just large enough to fit over one of the pimples, to which it is fastened by a strong but rather elastic muscle. So a sea urchin is able to move its spines about quite freely. Indeed, it sometimes walks with them as well as with the little sucker-feet, which it pokes out through tiny holes in the shell just as a starfish does, moving a few forward at a time, and so hitching its way along over the sand at the bottom of the sea.
If you succeed in finding a live sea urchin—and you can generally do so without very much trouble, by hunting in the pools among the rocks when the tide is out—you will notice that it has a very big mouth, with five perfectly enormous teeth. They are so huge, indeed, that if you had teeth as big, in proportion to your size, they would be about as large as good big carving-knives!
On some parts of the coast sea urchins are eaten as food, being scooped out of their shells with a spoon, just as we eat a boiled egg at breakfast. For this reason they are sometimes known as “sea eggs,” and those who have tried them say that they are very good indeed.
You would hardly think, perhaps, that a sea urchin and a starfish could be related to one another, for they do not look in the least alike. But if you take an urchin which has lost its spines, and examine it carefully, you will see that it is really a kind of rolled-up starfish, and you will be able to count its five rays quite easily.
1. THE SEA URCHIN WITHOUT SPINES.
2. THE SEA URCHIN WITH SPINES.
There is just one more thing that I must tell you about these very curious creatures, and that is that they are very fond of covering themselves all over with small stones, and little bits of broken shell, and tiny pieces of sea-weed, in order that they may not be noticed. They do this in a very odd way. I told you that they have numbers of little sucker-feet, which they poke out through tiny holes in their shells when they are required for use, just as the starfishes do. Well, when they want to disguise themselves, they just push out two or three hundred of these slender sucker-feet between their spines, and take firm hold with them of any small objects that may be lying within reach. In this manner they soon succeed in covering themselves all over, and you might easily look at one of them as it lay at the bottom of a rock-pool without recognising it at all.
CHAPTER VIII
SEA CUCUMBERS AND JELLYFISHES
PLATE XXXIX
THE SEA CUCUMBER (1)
IF you grope about in the dark nooks and corners of a rock-pool, quite close down to the water’s edge, when the tide is out, you may perhaps find a curious little creature which looks rather like a greyish-white cucumber, with an odd feathery tuft at one end of its body. This is a Sea Cucumber, or Sea Gherkin, and is chiefly remarkable because it seems to suffer very much at times from eating something which does not agree with it. Then it cures itself in a very odd way indeed. It gets rid of almost all the inside of its body, reducing itself to very little more than an empty bag of skin, with just a little tuft at one end! It throws off its teeth, it throws off the lining of its throat, it throws off all its digestive organs. You would think that it would kill itself by doing this, wouldn’t you? But it does not. And before very long new teeth, a new throat lining, and new digestive organs grow in the place of the old ones, so that in a few weeks’ time the animal is just as perfect as it was before!
1. SEA CUCUMBER.2. THE COMMON JELLYFISH.
It seems rather hard to believe that an animal can treat itself in such a manner as this, and yet continue to live, doesn’t it? But remember that “truth is stranger than fiction,” and that some of the strangest animals of all are found among those which live in the sea.
PLATE XXXIX
JELLYFISHES (2)
Jellyfishes are among the very oddest creatures which are found in the sea; for their bodies are made up almost entirely of sea-water! It is quite true, of course, that if you cut them in two the water does not run away. But then if you cut a cucumber in two the water does not run away; and yet cucumbers are made almost entirely of water. And the reason why it does not run away is just the same in each case. Both in the cucumber and in the jellyfish the water is contained in a very large number of very tiny cells; and if you cut either of them across you only divide a very small number of the cells, so that only a very small quantity of water escapes. But if you leave a jellyfish lying on the beach in the hot sunshine, and come back to look for it two or three hours later, you will not find it. All that you will find will be a ring-shaped mark in the sand, showing where the jellyfish had been lying, with just a few threads of animal matter in the middle. All the rest will have evaporated, because it was nothing else but water.
All the same, jellyfishes are very wonderfully made; and perhaps the most wonderful thing of all about them is the fringe of long, slender threads which hangs down from the edges of their bodies. For these are the fishing-lines by means of which they catch their prey. Jellyfishes feed on all sorts of tiny creatures—the fry of fishes, and the zoeas of shrimps and prawns, for instance—and if you were to see one of these swim up against those terrible threads, you would notice that it at once became paralysed, and that in a very few moments it would be dead. The fact is that all the way along these threads are set with hundreds and hundreds of tiny oval cells, each of which has a very slender dart, with a barbed tip, coiled up like a watch-spring inside it. And the cells are made in such a way that as soon as they are touched they fly open, and the little darts leap out. So, you see, if any small creature swims up against the threads numbers of darts at once bury themselves in its body. And, as these darts are poisoned, it dies in a very short time.
Jellyfishes can swim through the water by spreading and contracting their umbrella-shaped bodies, and you may sometimes see them travelling about in such enormous numbers that the water is perfectly thick with them.
PLATE XL
THE STINGING JELLYFISH (1)
Sometimes, after a strong south-westerly wind has been blowing for a day or two in the early part of the autumn, you may find a brownish yellow jellyfish lying upon the shore. It has a circular body about as big as a soup-plate, fringed all the way round with great masses of long yellow hairs. And if you find one of these creatures you are almost sure to find another before very long, and then another, and then another; for they nearly always swim about in shoals together.
Now, if you do meet with one of these jellyfishes, be very careful not to touch it with your bare hands. And if you should happen to be bathing, and to see one floating in the water near you, just get out of its way as fast as you possibly can. For those long yellow threads which hang down from the margin of its body sting just like nettles, and the least touch from them will cause a great deal of pain. If you have a thin skin, indeed, the sting of this terrible jellyfish may make you very seriously ill, and several weeks may pass before the effects of the poison pass away.
Yet the fishing-threads of this jellyfish are scarcely thicker than hairs, and the little darts which do so much mischief are so slender that you cannot see them at all without the help of a good strong microscope. Doesn’t it seem strange that such tiny weapons can be so dreadfully poisonous?
PLATE XL
THE SEA ACORN (2)
This is a very common jellyfish indeed; yet hardly anybody ever sees it. That is because it is very small and very transparent, so that as it swims about in the water it is almost invisible. And if it is flung up on the beach it dries up in a very few minutes. But if you want to look at it, you can very easily do so. On a warm, still day, when the sea is quite smooth, just dip a small net into the water, and work it gently to and fro. Then lift it out and examine the sides carefully, and you are almost sure to see three or four little lumps of jelly, not much bigger than peas. These are sea acorns, and if you put them into a glass vessel of perfectly clean sea-water, you will very soon find that they are swimming about. For though you cannot see the animals themselves, which are quite as transparent as the water, you will notice little flashes of coloured light, sometimes blue, sometimes green, sometimes yellow, and sometimes red, which just gleam out for about half a quarter of a second, and then disappear. You might almost think that a tiny rainbow had been dissolved in the water.
1. THE STINGING JELLYFISH.2. THE SEA ACORN.
The fact is this. Running round the oval body of the sea acorn are eight narrow bands, and on each of these are a number of very tiny scales, placed one above another, which keep on rising and falling again, like so many little trap-doors. These scales are really paddles, by means of which the animal drives itself through the water, and as they move up and down they catch the rays of light and break them up, just like that triangular piece of glass which we call a “prism.” And though you cannot see the jellyfish itself you can see these little flashes of coloured light, and so can trace the course of the little creature as it travels slowly along.
This curious jellyfish has only two fishing-threads, which hang down from the lower part of its body. But from each of these a number of little side-threads spring out, just like the “snoods” on the lines which fishermen use in the sea. And the animal is always throwing these out and drawing them in again, so that it really “fishes” for the tiny little creatures on which it feeds.