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THE USEFUL SPONGE

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inner mind to tell it how. Presently it begins to show thicker substance forming, and its shape grows to be like that of sponges you have seen. It sucks water into the tiny holes such as you see in sponges and then draws itself together so as to drive it out through large ones. This is its work; and, just as you squeeze a sponge in water and then let go, the sponge, by contracting and expanding, pumps the sea water into its innermost chambers, with what it may bring for food.

Everywhere, inside and out, the sponge frame is coated over with slimy stuff that is its real flesh. In that there are cells which divide and make new cells, and so keep the sponge growing larger till it gets its growth.

There are sponges all along our coasts; but when the slimy part has been washed off they are not fine and soft, and yet tough and strong, like those we get from the Mediterranean Sea and other far away shores.

To get perfect ones without breaking them, people called divers go down to the sea bottom to gather them from the rocks.

XXIX. THE SEA ANEMONE

EVEN from the picture you must be able to judge that this flower-like creature might be exquisitely beautiful. See if you cannot think into the halftransparent stem, with its many quivering arms, all the purest and most delicate of the

colors, pink, yellow, salmon.

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You see that the anemone does not move about, and so is depending upon those fleshy tentacles to seize whatever

may pass by that is fit for food and

bring it to the center where it can nourish the creature's life. If we were the victims, the beauty of the sea flower would not mean much to us, for it is as greedy a creature as ever lived. But we are studying to see how the wonderful thing we call life uses different sorts of bodies to maintain itself. "Pretty is that pretty does" cannot be a rule for such beings, who know no higher law than to live and grow.

One of the things that put this form of life above that of the polyps is that the center of the flower is a round open sac. We call it a stomach. Another

THE SEA ANEMONE

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is the way its babies are born. They are thrown out from the center into the sea, where the light forms float about a little while and then cling to some substance for support, as the sponge children do.

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picture. There is sure to be something interesting to see in it.

The walls will be lined with clinging barnacles and snails of all sizes, and there will be sure to be tough, leathery plants of red, yellow, and brown

colors, and possibly a crab or two crawling about with a sidewise motion. If the tide comes to wash it every day and keep its waters pure there may be anemones in it. These children are looking for starfishes and sea urchins, which they have seen on the beach but never before in the water. If you do not chance to come upon sea anemones when they are feeding, very likely you may overlook them, for the tentacles curl back and the stem settles down and they appear only as little mounds of thick grayish jelly.

Sea anemones have a pretty way of attaching themselves to the piles of bridges which the tide washes every day. When their bright clusters of tentacles are all in motion it seems as if the black posts were wreathed with flowers.

XXX. TOOLS TO WORK WITH

THE different parts of the creatures we have studied were their tools or organs to work with, and the work was breathing, growing, feeding, and moving about.

The lowest forms had simple organs and used them for everything. Any part of a hydra will do for a stomach, but if you cut a sea anemone in two you will kill it. The higher the animal is the more tools it has, and the harder it is for it to get on without each one.

This is the way it is in the world of people. Savages can make the few things they need, but, as we saw in Book Two, it takes a multitude of trades to provide for the wants of civilized people, and the tools that are used are nearly countless.

We have set the amoeba, the sponge, the hydra, and the anemone side by side to show a kind of staircase or ladder which the invisible worker Life has builded, with creatures for the steps. The next lesson shows higher steps and so more organs or instruments. Even simple eyes for seeing, feet for walking about, and nerves to warn of danger would be upward steps.

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