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.
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.