But other sponges help in this work. One is a brilliant crimson, and spreads a velvety mantle over the shell, from which rise branches as big as your fingers. We may probably discover among others here the pretty urn-sponges, like clusters of yellow or gray goblets about half an inch high. On the reefs of the Gulf coast of Florida, you know, several sorts of sponges grow to great size and are gathered and prepared for use—a trade which furnishes employment to hundreds of men.
But this clear pool holds more beautiful things than sponges. If we are fortunate we may find a sea-anemone. Do not fancy from its name that it looks anything like the pretty pink and white anemones that delight you in the woods in the spring. It does, indeed, look something like a clove-pink, or some sorts of chrysanthemum, when it is fully expanded, yet it is not a flower at all, but a true animal.
Its body is shaped like a barrel, or sometimes more like a tube, with a large throat leading into a big stomach which is held in position in the center of the body by six partitions radiating like the spokes of a wheel from the stomach to the tough outer skin. Between these are other shorter partitions extending inward from the skin, but not reaching the stomach.
This is the type of structure in the polyp family, which the sea-anemones represent; and the stony coral-polyps are built on the same plan, only there the outer wall and the radiating inside partitions become hardened plates of lime as the animal grows, and form, when many grow into a solid mass, the immense coral reefs described on page [433].
The New England coast has several small sea-anemones, and one handsome one, sometimes as big as a teacup, a few of which dwell in our pool. Just come, very quietly, over to this side, and gaze down through the clear water upon that reddish block of stone. Do you not see that large brown tuft, quivering and moving like a chrysanthemum each petal of which was alive? That is the brown sea-anemone; but some specimens show much brighter tints.
Ah!—did you notice how that minnow turned and fairly flew as he felt a touch of one of those waving petals? No wonder he was in such a hurry to escape from its clutches, since he knew quite well that the grasp of those arms means death. For every one of them is set with scores and scores of tiny oval cells, made in such a way that they spring open at the slightest touch. And inside each cell is a slender poisoned dart, which leaps out as soon as it is opened.
So, if the minnow had waited a few minutes longer hundreds of these little darts would have buried themselves in the soft parts of his body and stung him to death, and then the anemone would have swallowed him!
Now just touch the anemone with the tip of your finger. You need not be afraid to do so, for its little poisoned darts are not nearly strong enough to pierce your skin. There! do you see how its arms at once come closing in? It seems to be pushing them right down into the very middle of its body. Now they have entirely disappeared, and you cannot see them at all. The animal looks just like a shapeless lump of jelly.
Yes, it always does that when it is frightened, and also if it is left high and dry when the tide goes out. And when it catches a good-sized victim and swallows it, it generally remains closed up for at least a couple of days.
Now let us tell you another curious thing about the anemone. It looks as if it were growing out of the rock, doesn't it? If you try to push it loose, you will probably kill it before you succeed. Yet it can release it's sucker-like grip, and move about if it wishes to. This is only one of many very interesting things to be learned about these lovely creatures.