That is the way the Anemone obtains its food. As soon as the feelers get hold of a small animal they carry it to the opening of a tube in the centre. This is the mouth, leading to the stomach. Very often the feelers, with their victim, are tucked away into the stomach, and the feelers do not appear again for some time. Is not this a strange way of eating!
Much stranger still is the way in which the food is held, and made so helpless that it cannot escape. On the skin of the Anemone there are many thousands of very tiny pockets, or cells. Each cell contains a fine thread with a poisoned barb at the tip, The thread is packed away in the cell, coiled up like the spring of a watch. As soon as anything presses against the cells they shoot out their threads. Thus the tips of many poisoned threads enter the skin of any soft animal which is unlucky enough to touch an Anemone.
If your own skin is tender, these little stinging hairs will irritate it, but not enough to hurt you. It is different, however, with the small creatures of the sea. They are made quite helpless when caught by hundreds of these strange threads. We shall find similar poison-threads in the Jelly-fish; and these, in some cases, can cause us serious illness. You cannot see them without the aid of a microscope.
All those parts of its food which the Anemone cannot digest, it throws out again. If you feed an Anemone on raw meat, it tucks the pieces into its mouth, and, some days after, throws out the hard part of the meat, having taken all the "goodness" from it.
No doubt the Anemones themselves are eaten by other animals in the sea, but many kinds of fish will not touch them. You may remember that we noticed an Anemone which lived on the stolen home of the Hermit Crab.
The crab lives in the whelk sh.e.l.l, and the Anemone lives on the roof, as it were. In nearly every ocean, all over the world, these two partners are found, using the same sh.e.l.l. It is thought that the Anemone lives there for two good reasons. First, the Hermit moves from place to place; you can see that this would give the Anemone a better chance of obtaining food. Also, bits of food float to the Anemone when the crab is picking his dinner to pieces.
The crab seems to like having his strange partner with him. No doubt the Anemone is of some use to him, or he would at once pull it off. It is thought that the Anemone protects him from his enemies, the fish. Some of them would swallow the whelk sh.e.l.l, crab and all, but they would not eat one on which an Anemone was fixed. We are not _sure_ that these reasons are the right ones. All we know for certain is, that a crab and an Anemone have, for some good reasons, gone into partnership.
Anemones have large families. Sometimes they have numbers of eggs; at other times their little ones come straight into the world as very tiny Anemones. A boy who kept a large Anemone in a tank of sea water, was astonished to find that in a short time, he had not one, but hundreds, of the creatures. The tiny Anemones were fixed to the gla.s.s and rock, all fishing for food with their little outspread tentacles. Sometimes the Anemone will calmly divide itself into two, each half becoming a perfect Anemone!
Anemones are of many shapes, sizes, and colours. The loveliest of our British ones is the Plumose Anemone. It is like a carnation, and may grow to be six inches high--that is, nearly as long as this page. It is known by its shape, not by its colour. It may be any of these colours--brown, deep green, pale orange, flesh colour, cream, bright red, brick colour, lemon, or pure white.
There are many other creatures in the sea which resemble plants and are often mistaken for them. The Sea Lily (p.49) is one of the flower-like animals; it is a relative of the Starfish, living in deep water. The Sea Mat (p.59) is often found on the sh.o.r.e. It seems like a h.o.r.n.y kind of weed, but is really a colony of tiny animals, each one having its own little cell to live in.
EXERCISES
1. How does the Anemone expand its "feelers"?
2. In what way does the Anemone catch the small animals on which it feeds?
3. Where is the mouth of the Anemone?
4. In what way might the Anemone be of use to its partner, the hermit crab?
LESSON VIII.
SEA-WEEDS AND SEA-GRa.s.s
We think of weeds as useless plants which insist on growing just where they are not wanted. So it is a pity that _Sea-weeds_ are so named, for the part they play in the sea is a useful one; and they are often beautiful, though they do not bear flowers like so many plants of the land. You see draggled heaps of them, lying on the sh.o.r.e where the waves have thrown them. They are best seen in their proper home, buoyed up by the water, and spreading out their broad coloured fronds, or long waving threads. There are, in many places, meadows of Sea-gra.s.s, and forests of Sea-weed! Mother Earth still has her carpet of green, even when covered by the salt water. The plants are very unlike those of the land, but, as you will see, they are of great use. We will suppose you put on a diving dress. Then you can walk out, under the water, and explore the forests of the sea.
Down by the line of low tide, before you have waded up to your knees, you find plants clinging to the rocks. They cover them with a slippery coat of green; when you turn these Sea-weeds over you find periwinkles and other animals feeding or hiding. Sea-weed makes good "cover" for the creatures of the rock-pools, who have many enemies to fear.
You notice that most of these sh.o.r.e weeds are green, sometimes as green as young gra.s.s. Pull up a bunch of the weed, and you find that it clings to the rocks and stones, but has no real roots. Seaweeds belong to a humble family in the world of plants, having no real roots, no flowers, and no real seeds. They can attach themselves to the stones or rocks.
Along comes a great wave, and perhaps they are torn up; but this does not harm them, for they still live as they wash to and fro in the water, until they cling to another rock. Or they are thrown on the sh.o.r.e to die, or else to be washed back to sea by the next tide.
[Ill.u.s.tration: SEA-WEED FROND.]
The Sea Lettuce or Green Laver is a common seaweed near the sh.o.r.e. Its broad, crinkled and bright green leaves are rather like those of a lettuce. Sometimes it is boiled to a jelly and used for food. Many other sea-weeds are good to eat, and on some coasts there is a regular sea-weed harvest.
Now wade into rather deeper water, and you find a great ma.s.s of the Bladder Wrack. Most schoolboys know it, for the little bladders of air in the leaves explode with a pop if you squeeze them. The Bladder Wrack, and others of the same kind, are torn up by the fierce waves in a storm, and tossed on the beach in heaps. They are gathered by the farmer who knows how to value a cheap manure for his fields. Some kinds are also of use in packing lobsters so that they come to market nice and fresh.
When you have walked--in your diving dress--to deep water, you find yourself among a tangle of olive-green weeds. They are below the line of low tide. All round you is a forest of dark-green ribbons with wavy edges. The ribbons are tough and very long, and cling tightly to the rocks. These ribbon-weeds, and others of the same kind, are known as Tangles. Round some parts of our coast they make wide, thick beds in the sea. Though the ribbons may be six feet long, they are not so wide as the palm of your hand.
Another sea plant, which grows in tufts in rather deep water, is called Irish Moss; it is green, brown or purple in colour. I do not know why it should be called Irish Moss, for it is not a moss, and it grows all round the English, as well as the Irish, sea-coast. But sea-weeds have strange names; indeed, many of them have no everyday names at all. Irish Moss is used for food, after being boiled to a jelly. It can also be made into a gum or glue, and has often been so used.
Now, if you were to walk still farther on the bed of the sea, into deeper water, you would find the prettiest of all the sea plants. These are the pink and red sea-weeds. You also find them on the beach, but only after they have been torn from their home in the deep water. They grow on the rocks, in pretty coloured tufts.
If you dive still farther, into the dark depths of the sea, you find beds of ooze and slime, and rocks and weird fishes, but no plants. Why is this? Like the land-plants, these sea-plants must have _light_. They cannot grow in the blackness of very deep water. Can you guess why some sea-weeds are green and others red? Those growing in the shallow water of the sh.o.r.e are green, like land-plants, because the sunlight reaches them. Only part of the light can pa.s.s through deep water; and so, in these shady places, the sea-weed is reddish in colour.
[Ill.u.s.tration: SEA MAT.]
We see, then, that (1) green sea-weed grows by the sh.o.r.e; (2) brownish-green sea-weed likes deeper water; (3) red sea-weed grows in deep water; and (4) in very deep water there is no weed at all.
We must not forget the gra.s.s of the sea. It grows in narrow blades, often a yard in length, and as wide as your thumb. It is not a sea-weed, but a real flowering plant, which, for some reason or other, loves to grow under water. It creeps in the sand and mud, with green leaves growing up as thick as corn in a cornfield.
All these waving green leaves make large meadows in the sea; and sea-snails, fishes, and crabs hide in it, just as all manner of living things hide in the gra.s.s of our meadows. The proper name of this strange plant is Sea Wrack. When dried, it is useful for packing up china, and covering flasks of oil.
Now we come to the real use of sea plants. They are food for all the hosts of small animals of the sea. These eat it as it grows; or else, like the mussel and oyster, swallow the tiny sc.r.a.ps of it which float everywhere like so much dust.
The sh.e.l.l-fish, and other animals which feed on sea plants, are themselves eaten by other sea creatures, and these in their turn are eaten by crabs, lobsters and fish, which are eaten by us. It reminds you of a chain. The first link in the chain is the sea plant, the last links are the fish and ourselves. So, you see, the weeds and gra.s.s of the ocean are of very great value indeed.
EXERCISES
1. Give the names of three common Sea-weeds.
2. What is the colour of the weed found in deep water?
3. Why cannot Sea-weed grow in very deep water?
4. In what way are sea plants most useful?
LESSON IX.
THE JELLY-FISH.
Or all the queer children of Nature which live in the sea, the Jelly-fish is one of the queerest. You often find it on the sh.o.r.e, especially after a severe storm. There it lies, a ma.s.s of helpless jelly, which slips and breaks through your fingers if you try to lift it.
It cannot move back to its watery home, and in a short time the sun"s warmth will have dried it up, leaving but a mark on the sand, and a few sc.r.a.ps of animal matter; for these strange creatures are little else but water. A Jelly-fish, which weighed two pounds when alive, would leave less than the tenth part of one ounce when dried!
There is a story of a farmer who, on seeing thousands and thousands of Jelly-fish along the sh.o.r.e, thought he would make use of them. He decided that they would serve as manure for his fields, and so save him much money. He went home, and sent men with wagons to be loaded with the Jelly-fish. This was done, and the Jelly-fish were spread over the soil.
On looking at his fields the next morning, the farmer was astonished to find that every sc.r.a.p of his new manure had vanished as if by magic!
[Ill.u.s.tration: WEST PAN SAND BUOY. ONE OF THE MANY BUOYS AT THE MOUTH OF THE THAMES.]
In the sea the Jelly-fish looks like an umbrella of bluish-white jelly, from which hang ta.s.sels and threads. Look over the side of a boat, or from the pier, and you often see them drifting by, hundreds of them, like so many ghosts.