CHAPTER XXXVIII

ANNELIDS AND COELENTERATES

The important class of the annelids contains those creatures which we generally call worms. There are a great many of these, but we shall only be able to mention one or two.

THE COMMON EARTHWORM

This worm is really a most interesting as well as a most useful animal. The way in which it crawls is decidedly curious. On the lower part of every one of the rings of which its body is made up, with the sole exception of the head, are four pairs of short, stiff, little bristles, projecting outward from the skin. The worm really hitches itself along by means of these bristles. First it takes hold of the ground with those underneath the front rings, then it draws up its body and takes hold with those underneath the hind ones, and then it pushes its head forward and repeats the process; and so on, over and over again.

If you take a worm and pass it between your finger and thumb from the tail-end toward the head, you can feel these little bristles quite easily.

A worm does not often leave its burrow, however, but generally keeps the tip of its body just inside the entrance, so that it can retreat in a moment in case of danger.

Worms make their burrows in a very odd manner, for they actually eat their way down into the ground, swallowing mouthful after mouthful of earth until their bodies can contain no more. Meanwhile they have been absorbing nourishment from this soil; but presently they come up to the surface and pour out the mold which they have swallowed in the form of what we call a worm-cast, after which they go down again and swallow more, and so on until the burrow is sufficiently deep.

You will be surprised, we think, to hear how much earth is swallowed by the worms in this way. Just think of it. Every year, in every acre of agricultural land all over the country, worms bring up from below, on an average, and spread over the surface in the form of worm-casts, no less than fourteen tons of earth, or about seven large cartloads!

This is why worms are such useful creatures. They are always, as it were, digging and plowing the soil. After a time the earth at the surface becomes exhausted. Nearly all the nourishment is sucked out of it by the roots of the plants. But the worms are always bringing up fresh, rich, unused soil from below, and spreading it over the surface in the form of what farmers call a top-dressing. They are doing, in fact, exactly what we do when we dig our gardens or plow our fields--burying the used-up soil that it may rest, and bringing up fresh mold to take its place.

But, besides turning the soil over, they manure it; for almost every night from early spring to late autumn worms are busy dragging down leaves into their burrows. With some of these leaves they line their tunnels, with some they close the entrances, and on some they feed. And most of them decay before very long and turn into leaf-mold, which is just about the very best manure that there is. So you see, the worms do not merely turn the soil over, they enrich it as well, and help very largely indeed to keep it in such a condition that plants can continue to grow in it.

THE LUGWORM

The similar lugworm lives in sandy mud on the sea-shore; and when the tide is out you may often see its casts in thousands. It is very largely used by fishermen as bait. When it is carefully washed it is really quite a handsome creature, for sometimes it is deep crimson in color, and sometimes dark green, while on its back are twenty-six little scarlet tufts, arranged in pairs, which are really the gills by which the worm breathes.

The burrows of the lugworm are not quite like those of the earthworm, for as its tunnels through the sand it pours out a kind of glue-like liquid, which very soon hardens and lines the walls, so as to form a kind of tube and prevent the sides from falling in.

THE TEREBELLA

This worm forms very much stronger tubes. It is common on many parts of our coasts. But it is not very easily found, for at the slightest alarm it retreats to the very bottom of its burrow, which nearly always runs under large stones and rocks.

The terebella makes its tube by means of the little feelers, or tentacles, which spring from the front part of its body. These have a most wonderful power of grasp, and one after another little grains of sand are seized by them, and carefully arranged in position. And when the tube is quite finished, the animal constructs a little tuft of sandy threads, so to speak, round the entrance, which you may often see in the pools left among the rocks by the retreating tide.

THE SEA-MOUSE

Looking far more like a hairy slug than a worm, the sea-mouse also belongs to the class of the annelids. You can easily find this creature by hunting in muddy pools among the rocks just above low-water mark; and most likely you will consider it as one of the dingiest and most unattractive-looking animals that you have ever seen. But if you rinse it two or three times over in clean water till every atom of mud has been washed out of its bristly coat, you may change your opinion. For now you will see all the colors of the rainbow playing over it--crimson, purple, orange, blue, and vivid green--just as if every hair were a prism. It would be difficult, indeed, to find any creature more beautiful in the waters of the sea. This bristly coat is really a kind of filter, which strains out the mud from the water that passes to the gills.

LEECHES

Leeches, too, are annelids, living in fresh water instead of salt water. They are famous for their blood-sucking habits, and when we examine their mouths through a microscope we find that they are provided with three sets of very small saw-like teeth, which are set in the form of a triangle. When a leech wants to suck the blood of an animal, it fastens itself to the skin of its victim by means of its sucker-like lips, and then saws out a tiny triangular piece of skin. That is why it is so difficult to stop the bleeding after a leech has bitten one. An actual hole is left in the skin, which does not heal over for some little time. And a great deal of blood is generally taken by the leech itself, which will go on sucking away until its body is stretched out to at least double its former size.

That is rather a big meal to take, isn't it? But then such meals come very seldom. Indeed, when a leech has once gorged itself thoroughly with blood, it will often take no more food at all for a whole year afterward!

Leeches lay their eggs in little masses, called cocoons, which they place in the clay-banks of the pools in which they live. In each of these cocoons there are from six to sixteen eggs.

We now come to the last great class of animals about which we shall be able to tell you--that of the coelenterates. It contains three most interesting groups of creatures.

JELLYFISHES

You may have seen plenty of jellyfishes if at any time you have been staying at the seaside, for they are often flung up on the beach by the retreating tide. But if you were to go and look for them two or three hours after seeing them, on a bright sunny day, you would find that they had disappeared. All that would be left of them would be a number of ring-like marks in the sand, with just a few threads of animal matter in the middle of each. The reason would be that they had evaporated! That sounds rather strange, doesn't it? But the fact is that the greater part of the body of a jellyfish is nothing but water! It is quite true that if you cut it in half the water does not run away. But then that is equally true of a cucumber; and cucumbers, too, are made almost entirely of water. The reason is the same in both cases. The water is contained in a very large number of tiny cells; and when you cut either the animal or the vegetable across, only a few of these cells are divided, and only a small quantity of the water escapes.

Round the edge of the disk of a jellyfish which has just been flung up by the waves you will find a number of long, slender threads. These are its fishing-lines, with which it captures its prey, and they are made in a very curious manner. All the way along they are set with a double row of very tiny cells, in each of which is coiled up an extremely sharp and slender dart. These cells are so formed that at the very slightest touch they fly open, and the little darts spring out; and, besides this, the darts are poisoned. So as soon as any small creature swims up against these threads a number of the venomed darts bury themselves in its body, and the poison acts so quickly that in a very few seconds it is dead. Then other threads come closing in all round it, and in a very short time it is forced into the mouth and swallowed.

Some jellyfishes are so poisonous that they are most dangerous even to man. Only one of these, however, is found in the North Atlantic, almost all the jellyfishes that one finds lying about on the beach being perfectly harmless. But if, when you are bathing, you see a yellowish-brown jellyfish about as big as a soup-plate swimming near you in the water, be sure to get out of its way as fast as you possibly can; for if its threads should touch any part of your body, you are almost sure to be very badly stung. There is very little doubt, indeed, that many swimmers have been killed by these creatures; while thousands of unwary bathers have been laid up for days, or even weeks, from the effects of their poison.

SEA-ANEMONES

What beautiful creatures are these--just like flowers growing under the sea! Some are like dahlias, some like chrysanthemums, and some like daisies, of all shades of crimson, and purple, and orange, and green, and it is very hard to believe that they are really living animals.

The tentacles of these creatures, which look so like the petals of flowers, are set with little cells containing poisoned darts, just like the fishing-threads of the jellyfishes. They can be spread out or drawn back into the body at will, and when they have all been withdrawn the anemone seems to be nothing more than a shapeless lump of colored jelly.

Anemones spend the greater part of their lives clinging to the surface of a rock at the bottom of the water, the broad base of the body acting just like a big sucker. They can crawl about, however, at will, and sometimes they will rise to the surface of the sea, turn upside down, hollow their bodies into the form of little boats, and then float away, perhaps for quite a long distance.

But few sea-anemones are seen on our eastern coast, because, except in the cool north, there are few rocks. On the warmer and rockier shores of California and northward, however, these lovely creatures occur in great variety.

CORALS

Last upon our list come those most wonderful little creatures which are known as corals.

These are often called coral insects, but that is a great mistake. For they have nothing to do with insects at all, and are as different from them in every way as they can possibly be. They are properly called polyps, and we can best describe them, perhaps as very small sea-anemones. But they have one property which the anemones do not possess, namely, the power of extracting lime out of the sea-water and building it up round themselves in the form of coral.

These creatures may be roughly divided into two groups, the one consisting of the simple corals, which only live together in very small numbers, and the other of the reef-builders, which live in vast colonies, and build up masses of coral of enormous size. The latter are by far the more interesting, and the way in which they build up immense banks of coral is very wonderful indeed.

Remember, first of all, that these animals multiply in two different ways--sometimes by eggs, and sometimes by little buds, so to speak, which grow out of the body of the parent. The polyps which hatch out from eggs swim about for some little time quite freely. But after a few days they fasten themselves down to the surface of a submerged rock, and after that they never move again. Other polyps soon come and settle down by them, and before very long there will be thousands upon thousands of the little animals all growing, as it were, close together, and all gradually building up coral underneath and round the margins of their bodies.

When they reach their full size they begin to multiply by "budding." Baby polyps sprout out all over their bodies, and these, instead of swimming about for a few days like those which are hatched from eggs, remain fixed where they are for the whole of their lives. Then they, in their turn, begin to deposit coral, and as they have nowhere else to put it they place it on the bodies of their parents, which before very long are completely covered in. Now, you see, there is a second layer of coral on the top of the first. Then in due course of time a third layer is formed upon the second, and a fourth layer upon the third, each generation being built in by the one that comes after it, till at last the coral bank rises above the surface of the water. Then the work has to stop; for these little creatures cannot live unless the waves can constantly break over them. But although the bank cannot be raised higher it can still be extended on all sides; and so the little polyps go working on, year after year, till at last the results of their labor are almost too wonderful to realize.

CORAL BANKS

These coral banks take three different forms.

First, there are the fringing reefs. These are great banks of coral surrounding the shores of a tropical island, or running for long distances on the coasts of the mainland. The island of Mauritius, for example, is entirely surrounded by a fringing reef. These reefs often spread out for miles into the sea, and they are only broken here and there by narrow passages, where some river or stream is flowing out. For the polyps cannot live in fresh water.

Next, there are barrier reefs. These are great walls of coral at a distance from the shore, with deep water between the two. For the polyps are unable to work at a greater depth than about thirty fathoms, or one hundred and eighty feet, below the surface; and it often happens that while there is deep water close to the shores of a tropical island, there is shallow water farther out. In such a case the polyps have to build out at sea, instead of close into the land, and there is a kind of moat between the coral bank and the shore. In this case the bank is called a barrier reef, and sometimes it is of enormous size. The Great Barrier Reef, for instance, runs for no less than 1250 miles along the northeast coast of Australia.

Then, thirdly, there are coral islands, or atolls. There are thousands of these wonderful islands in the Pacific and the Indian oceans, and others are still being slowly pushed up out of the sea. They always take the form of more or less circular rings, in the center of which is a lake of sea-water called a lagoon. The coral bank of which they consist is seldom more than a few hundred feet wide, but sometimes the islands are very large indeed. The biggest of all is ninety miles long and sixty miles broad, while several others are not very much smaller. Soon after they rise to the surface of the sea a kind of soil is deposited upon them, made up partly of powdered coral, ground up by the action of the waves, and partly of decaying vegetable matter which has been flung up on them. Then sea-birds bring mud upon their feet from the mainland, or from another island at a distance, and leave some of it behind them when they settle down to rest; and in that mud are seeds of plants, which soon begin to sprout and grow. So in a very few years the island is covered with low vegetation. Then one day, perhaps, a floating cocoanut is flung up, and that, too, takes root and grows, so that in course of time there is a palm-tree. Other palm-trees, of course, follow; and the result is that the first glimpse which a traveler gets of a coral island is nearly always that of a row of palm-trees upon the horizon.

The simple corals live in almost all parts of the ocean. Some of them are occasionally dredged up off our coasts, and can live in very cold water. But the reef-builders are only found in warm seas, and are never found working far outside the boundaries of the tropics.

How wonderful it seems that tiny creatures such as these polyps, which really do not appear to be much more than little lumps of living jelly, should be able to build up these vast masses of coral from out of the depths of the sea! One cannot help wondering what the results of their work will be if the world should last for a few thousand years longer. It would really seem that by that time the tropical seas will be choked up with coral islands, and the lagoons inside them will be filled up with coral too; so that not merely islands, but continents, will have been raised from the ocean by some of the smallest and weakest and most insignificant of all living animals!

WALKS WITH A NATURALIST

Suggestions for Teacher and Pupil in Nature Study

I

SPRING

Let us suppose that we are taking four country walks together, and trying to use, in actual experience in the field, the information we have been reading. The first shall be in the spring, the second in summer, the third when autumn leaves are falling, and the last in midwinter. We will go along the field-path, follow the lane through the woods to the creek, then down the stream to the road, and so homeward.

There is plenty to be seen, this bright spring morning. The birds are very busy, of course, for they have nests to build, and eggs to lay, and little ones to take care of; so they are hard at work from the very first thing in the morning till the very last thing at night. Almost every sparrow that we see has a feather or a piece of straw in its beak, and the robin which has just flown out of that tree with a terrified squall has already finished building, and was most likely sitting upon her eggs. Yes, there is her nest, you see, right on the lowest limb, with four greenish blue eggs.

See that catbird, all lead-color, with a black cap. See her dodge into that bush just beyond us. It is just the place for her nest; and, sure enough, here it is. It is a rough affair, but she mews as pitifully at us as if it were the finest of homes, and half a dozen other birds are already screaming their sympathy. Let us just look at the eggs, and remember that they are a deep polished green, and then walk on, for the poor mother is very unhappy. We have no use for the eggs, and it would be shameful to rob her; and, besides, we should thus destroy the coming lives of four catbirds, who will be too useful as insect-hunters in our gardens to be wasted.

This path is dusty, and we notice a great many pinhole doors of the little black ants. The ants are running in and out of them, and if we should carefully dig up the ground we would find a labyrinth of narrow passages, here and there widening into chambers, and so learn that these tiny holes are entrances to an ant-city whose streets are all subways.

Here are some larger ants--three times as big--a regular procession of them going and coming out from under that half-buried stone, winding through the grass, and then trotting up and down this tree-trunk. A lot of them go out along that low limb. Let us climb upon the fence, and try to see what it is that attracts them. Ah! This is the secret. Clustered thickly on the bark are hundreds of minute green creatures, smaller than pinheads. They are busily sucking the sap from the bark, and seem to interest the ants greatly, for they are stroking these bark-lice (aphids) with their feelers, and if we had a magnifying-glass we could see that they were licking up a honey-like liquid which oozes out of two short tubes on the back of each aphid.

A little distance beyond the ant's apple-tree a young maple stretches one of its branches out to the sunlight just above our heads, where the sharp eyes which young naturalists must keep wide open when they walk abroad will notice a bird's nest hung under the shelter of its broad outermost leaves. It is one of the loveliest nests in the world. A slim, graceful, olive-green little bird glides out from beneath the maple-leaves as we approach, perches near by and watches us silently. Though she does not mew and scream as did the catbird, she is just as anxious, you may be sure. Be easy, dear little vireo--for we know your name--we shall not ruin your home. Let us pull the branch gently down a little. Now we can see that the nest is a round hammock, woven of grapevine bark and spider-web, and hung by its edges. It seems too fragile to hold the weight of the mother, slight as she is; and in it are three white eggs with a circle of pink and purple dots around their larger ends. But here is also a fourth egg, much larger, grayish white, and speckled all over with brown.

That is the egg of the cowbird, a sort of purple, brown-headed blackbird which you may almost always see in pastures where there are cattle. The cowbirds, like the European cuckoos, never build any nests of their own, but put their eggs into those of other birds, and leave them to be hatched. And they are very fond of choosing the nest of a vireo. One would think that the mother would notice at once that a strange egg had been placed in her nest, and would throw it out. But she never seems to do so, but sits on the cowbird egg as well as on her own, so that in course of time she hatches out three or four little vireos and one young cowbird. Then what do you think the stranger does? Why, as soon as the mother vireo goes out to look for caterpillars for food, it begins to wriggle underneath the other little birds, and soon shoves them out of the nest, one after another. Still more strange is it, that when the vireo comes back she never seems to care that her own little ones are all lying dead on the ground below, but gives all the food that they would have eaten to the cowbird. And the greedy cowbird eats it all! Until it is fledged she feeds it in this way, and takes the greatest care of it, and even after it has left the nest and is able to fly about she will come and put caterpillars into its beak.

Look at the trunk of this tree. Why has so much of the bark fallen away from the wood? And what is this curious pattern engraved, as it were, upon the wood--a broad groove running downward, and a number of smaller grooves branching out from this on each side?

Ah! that is the work of a very odd little beetle, with a black head and reddish-brown wing-cases. About eighteen months ago, probably, a mother beetle came flying along, settled on the tree, and bored a hole through the bark, just big enough for her to pass through. Then she began to burrow downward between the bark and the wood, cutting the central groove which you see in the pattern. As she did so she kept on laying eggs, first on one side of the groove and then on the other, in the short branch-tunnels, which she cut out as she went along. In this way she laid, perhaps, eighty or ninety eggs altogether. When the last had been laid she turned round, climbed up her burrow again, passed into the hole by which she came in, and--died in it! And by so doing she blocked up her burrow with her dead body, and so prevented centipedes and other hungry creatures from getting in and eating up her eggs.

Early in the following spring all the eggs hatched, and out came a number of hungry little grubs with hard, horny heads and strong, sharp little jaws. Every one of these grubs at once began to make a burrow of its own, boring away at right angles to the groove made by the mother beetle, and cutting away the fibers which bind the bark to the wood. The consequence was, of course, that by the time they were fully grown quite a big piece of bark had been cut away. And very likely if we were to come and look at the tree again in two years' time we should find that the whole of the trunk had been completely stripped.

"Then these little beetles are very mischievous?" Oh, no, they are not; for they never touch a healthy tree. They only attack those trees which are sickly or diseased.

Here we are on the banks of the stream. Let us make our way home by the path which lies beside it.

Ah! Did you see that flash of blue and white and orange that went darting by, almost like a streak of many-colored light, sounding a loud rattling call as he flew? It was a kingfisher, and if we stand quite still for a minute or two, without moving so much as a finger, we shall very likely see him again. Yes, there he is, sitting on that branch overhanging the stream, and peering down into the water beneath. He is watching for little fishes, upon which he feeds. There, he has caught sight of one, and down he drops into the water, splashes about for a moment or two, and then rises with a minnow in his beak. Back he flies to his perch, slaps the little fish against the branch once or twice to kill it, jerks it up into the air, catches it head foremost as it falls, and then swallows it with one big gulp. A moment later he is peering down into the water again on the lookout for another.

That hole in the face of the steep bank across the stream is the doorway of the kingfisher's home. If we could get there, and should try to dig it, we would find it a hard task; for from that round door a tunnel runs into the ground probably six or eight feet, and ends in a chamber where lie half a dozen pure white eggs, resting upon the bones of fishes and scraps of every sort, which make a very ill-smelling place for the young kingfishers to be born in; but they do not mind that.

The butterfly that has just floated by is a small tortoise-shell, and it has lived through the winter, which kills nearly all of the butterfly tribe. That is why its wings are faded and chipped, for it had six or eight weeks of active life before it hid itself away, last of all, in a hollow tree, and entered upon a six-months' slumber. Sometimes, on a warmer day than usual, these and certain other butterflies will be roused up, and will flutter about in the sunshine, so that now and then you may capture a tortoise-shell even in the Christmas holidays.

The warm May sunshine is enticing out many a minute insect--gnats and flies especially. Dancing companies of small sulphur yellow and other companies of blue butterflies whirl about one another over the rapidly growing grass.

Have you noticed among the May flowers how many are yellow? There are dandelions, and yellow violets, and the modest fivefinger low in the herbage, while above them tower great tufts of wild mustard and indigo, the buttercups, the marsh-marigold, and many another.

The frogs and toads are less noisy than a month ago, and one sees fewer masses and strings of eggs in the roadside ditches than in April; but in their place the pools swarm with tadpoles, and it will be well worth your while to keep watch of their growth. Try to find out what they eat, and what eats them. Observe when the tail begins to disappear, and how it is lost; when the legs begin to appear, and which pair first shows itself. You may learn a lot of interesting facts about frogs and toads before the summer is done, if you are diligent.

In this stream are a few turtles. Can you tell when and where they lay their eggs? Keep careful watch of the little sandy beaches, and perhaps you may see one digging a hole in which to bury her set of sixty or so, leaving the sun to supply a better warmth than she could give them.

May is a month of activity for snakes. They have thrown off the stiffness and drowsiness of their long winter torpidity, and, grown thin after five months of fasting, are running about in search of food. Let the frogs and toads, the beetles and young ground-sparrows and mice--also weak from their winter trials--take heed, for the swift blacksnake or sly garter, or rapacious water-snake will seize them before they have time to squeal!

The water in the stream is still cool, but the fishes are struggling up the current, pickerel are spawning in the weedy shallows, and among the pebbles of the bottom a host of young creatures are beginning to grow vigorous.

None among them is more active than the larval caddis-flies, or case-worms, as anglers call them. Here is a caddis-fly now, its gauzy wings folded tentwise over its back. All its earlier life was spent in the water, and when it was a grub it lived in a very curious case, which it made by cutting up a rush into short lengths, and sticking them together by means of a kind of natural glue. When once a caddis-grub has made one of these cases it never gets out of it again, but drags it about wherever it goes. And if you try to pull it out you will find that you cannot do so without killing it. For at the end of its body it has a pair of strong little pincers, with which it holds on so firmly and so doggedly to its case that you might actually pull it in two without forcing it to loose its hold.

There are different kinds of caddis-flies, however, and the grub of one kind fastens grains of sand together to make a case, while that of another sticks two dead leaves face to face, and lives between them.

It would be an interesting task for a boy or girl to see how many different kinds of caddis-flies, judging by their cases, lived in the stream, and to keep them alive in an aquarium, and watch their behavior and changes.

II

SUMMER

A walk in midsummer is a stroll through what seems a quiet world compared with the noise and brightness of May. Then every leaf was green and crisp, every bird in full song, and the world seemed to have an air of gay youth, like a vigorous boy or girl full of eagerness and activity.

Now as July draws toward its end the eagerness has subsided and the year, like a lad grown a little older and more serious, has settled down to regular work. Had our walk been taken before breakfast, we should have heard no end of birds singing, it is true; but about the time the dew dried from the grass most of them ceased their music. One reason, besides the noonday heat, is that they are too busy to sing, for the husband and father--and he is the singer of the family--must now help his mate feed her young. We fear, however, he is not a very good provider after the fledglings quit the nest, leaving most of their support and schooling to the mother. At this season one may often come upon and watch a little family group of this kind, and perhaps we may do so.

Meanwhile let us sit down for a moment on this grassy bank--not too near that fence-post, for do you not see twined about it that vine with the reddish hairy stem, and the shining leaves in groups of threes? That is the poison-ivy, which may cause an itching rash to break out upon your skin if you touch it. You must learn to recognize and avoid this "ivy"--which is not a true ivy, but a kind of climbing sumach--before you go poking around in the fields, or you will be sorry. Do you notice the delicious beeswax-like odor in the air? That comes from the big yellow branches of blossoms on another and perfectly harmless kind of sumach--that scraggly sort of bush just beyond the fence.

See how the bees are humming about it--some of them honey-bees from a farmer's hive, others big bumblebees and small burrowing kinds. All are in search of the minute drops of sweet liquid which each of the tiny flowers in the blossom-head contains, and which turns into honey after it has been carried a little while in the insect's crop, or lower part of the throat, where it lodges. Then it is suitable to be really swallowed, or to be coughed up and fed to the young bees at home, or stored away in the cells of such bees as store up honey, for many wild bees do not make such stores.

Besides its nectar, however, every flower contains a quantity of small particles, like dust, which are produced in the heads of the little thread-like interior parts of the blossom called the stamens; and in order that the flower shall turn to a seed it is needful that some grains of this dust, or pollen, shall fall upon another hollow part called the pistil, and so pass down into its base. It is much better that the pollen of one flower shall get into the pistil of another than into its own. The wind manages this to some extent--especially for the grasses--by shaking or blowing the loose pollen out of one flower and into another.

But the bees help this process greatly, and so may be said to pay for the sweets they use. Watch this one buzzing in front of that clump of jewelweed. Suddenly the loud humming ceases, and the bee crowds herself into the hanging, bell-like blossom, searching for the nectar. Now she is backing slowly out, and you may see how her furry body is half-powdered with yellow dust. That is pollen; and when she dives into another "jewel" she will brush some of it off against the pistil there, which is right in her way, and is very glad to accept her gift. So the bees and other insects humming about the flowers in this hot sunshine are not only getting their living but helping the plants to keep vigorous and produce lots of healthy seed.

Now let us move on. The sky is filled with swallows. There are the fork-tailed ones that make their nests inside the barn; the square-tailed ones that form their curious bottle-shaped nests of mud on the outside, under the eaves; and the purple martins that live in our bird-house in the garden. They are darting and dashing and skimming about in mid-air as though they did not know what it is to be tired; and if only they were a little closer we should see that every one of them has its mouth wide open. The reason is that these birds have very sticky tongues, and that all the time they are in the air they are chasing flying insects, bothersome gnats and mosquitoes among the rest. As soon as one of these insects is touched by the tongue, it sticks to it. Then, without swallowing it, the bird tucks it away in the upper part of its throat, and goes off to hunt for another. After a time it has quite a ball of little bugs packed away in this curious manner, and can carry no more; so it flies off to its nest, and divides them among its little ones.

Do you see that small olive-green bird sitting very erect on that fence-post? There--it suddenly springs into the air, flutters up and down for just half a moment, and then returns to the post. It is a flycatcher, and for hours together it will go on catching insects just in that same way. As it alights it tells us its name, calling _Phoe-e-be, Phoe-e-be_ in a sad sort of voice, though there is no reason to think it is sorrowful at all. If we should go down to that bridge over the stream in the valley we would find its solid nest of moss and mud among the stones of one of the piers.

The woodland path is not so good a place for birds as are more open spaces; but one hears here the distant cooing of a dove, the _chip-chur-r-r_ shout of the scarlet tanager, as red as fire everywhere except on its black wings and tail, and often the tapping of a woodpecker. There is one at work now on that tall dead stub. If you want to see him you must keep perfectly still, for if he notices that he is watched he begins to think some harm may follow, and either flies away or stops work, scrambling around the trunk and peering out from behind it with one eye to see what you mean to do next. See how firmly he clings to the trunk. If you were close enough you could see that two of the large-clawed toes at the end of his short strong legs and feet were straight forward and two straight backward; and that he is also propping himself up by means of his short stiff little tail, which is bent inward, and really serves as a kind of natural camp-stool! Now he is pecking away at the bark with his strong chisel-like beak, and making the chips fly in all directions. Most likely the grub of some burrowing beetle is lying hidden in the wood below, and he is trying to dig it out. But he will not have to dig down to the very bottom of its tunnel, for he has a very long slender tongue with a brush-like tip; and this tip is very sticky. And with this, after he has enlarged the mouth of the burrow, he will lick out the little grub which is lying hidden away within it.

Now let us make our way to the path by the side of the stream.

What a number of galls there are on these oak-trees--some on the leaves, some hanging down from the twigs in clusters, like currants, and some growing on the twigs themselves! Do you know what causes them?

Well, a very tiny fly pricks a hole in a leaf, or a young shoot, by means of a kind of sharp sting at the end of her body, and in that hole she places an egg, together with a very small drop of a peculiar liquid. This liquid has an irritating effect on the leaf, or twig, and causes a swelling to grow; and when this has reached its full size, and become what we call a gall, a little grub hatches out of the egg, and begins to feed upon it. Sometimes there are several grubs in one gall. If we were to cut one of those large red and white "oak-apples" to pieces, probably we should find as many as a dozen, each lying curled up in a hollow which it had eaten out.

If a naturalist had to choose some one place in which to carry on his outdoor studies, he could find none better than the course of a small rural river, and a year's work would not exhaust it. Just now, in midsummer, he would be most interested in the nesting of the sunfish and minnows. Let us steal quietly to the brink, where the turf forms a little bank, a foot or so high, to which the bottom slopes up in clear sand and gravel, with here and there a clump of bulrushes. Let us lie down and scan this bottom through the clear water rippling gently by, keeping very quiet, so as not to alarm any fishes which may swim near, for they are the very fellows we wish to see.

Here comes a little one--a common shiner--no, a golden one--stealing cautiously toward an open space. A much smaller fish--not so big as your little finger--shoots past him and stops as suddenly as if it had run against a wall, then an instant later is off again so swiftly you can hardly see it move. No wonder it is called Johnny Darter! Meanwhile the shiner, a minnow in a scale-armor of burnished gold, moves slowly on. Where is he aiming? Ah! look over there. Do you see that low ring of sand, about as large as a dinner-plate, running about some clear gravel, as though the plate were strewn with small pebbles?

That is a nest of a sunfish; and look! did you see the swoop of that gray shadow from the bulrushes? The shiner turned and fled like a bright streak through the water; and now the gray shadow is poised over the dish-like nest, and we see that it is the blue-eared sunfish, or "punkin-seed," as you say the boys call it when they go a-fishing.

See how with its breast-fins it fans the gravel among which its eggs are lying. They are so small and transparent that we cannot see them, but they are there, and must be kept clean. So the fish stirs the water and the current sweeps away everything which may have lodged there while the owner was away for a few minutes. But he never goes far, for he must guard his treasures against enemies like the shiner and other fishes, salamanders, water-bugs, and the like, which would eat them if they dared.

Butterflies innumerable greet us and dance along the roadside, as if to see us safely home. Many are small and yellow, or white and yellow, with handsomely bordered wings, and they are greatly interested in the clover. Then we see plenty of little blues, very regular in outline, and with them various coppers, distinguished by their orange and brown colors, each with a coppery tinge and set off by black markings. The hair-streaks are brown, too, with delicate stripes for ornaments on the lower surface, which are shown neatly when the wings are closed upright above the back. Did you know this was one of the distinctive marks of a butterfly? A moth never holds its wings on high in that fashion.

But it is the larger butterflies that first catch the eye, such as the monarch and the viceroy, the fritillaries, fox-red and black, with trimmings of silver; the red admiral, and other anglewings, beautiful in outline as well as in colors; the delicately pretty meadow-browns, and the magnificent swallowtails and mourning-cloaks.

Don't you think it would be interesting and delightful to study these exquisite creatures?

III

AUTUMN

It is a bright warm day in October; and once more, as we go for our ramble, everything seems changed. The autumn flowers are blooming, the autumn tints are in the leaves; and again there are different animals, and different birds, and different insects almost everywhere around us.

We hardly take ten steps before there is a sudden commotion in a clump of tall grass by the path, and a red-backed mouse leaps almost over our toes and dives down a little hole which otherwise we should not have noticed. Doubtless he carried a mouthful of grass-seeds to add to his granary under ground. All over the country mice and gophers and squirrels are doing the same thing. There's a big gray squirrel, now, scratching a hole in the ground as busily as a terrier who thinks he smells a mole. Suddenly he stops, drops a hickory-nut into the little grave, paws the dirt and leaves over it, pats them down, and canters away. All day he is burying nuts so that when, next winter, the trees are bare, he may dig them up and feed upon their meat. Sometimes he doesn't need to, or forgets, and then a tree may spring up. Many a fine hickory or chestnut was planted in this way by squirrels.

What is that red squirrel doing under the chestnut-tree by the side of the lane? He is hard at work collecting chestnuts, stuffing his big cheeks with them and carrying them away to hide for use next winter. He seems to realize that although he will sleep in his bed under the stone fence almost the whole time from Thanksgiving to Easter, he will wake up now and then, on warm days, and will feel dreadfully hungry. But then there will be little to be found in the way of food. So he is now gathering nuts and acorns and dry mushrooms, and hiding them away so as to be prepared. Some he puts in a hole in the trunk of a tree, others in crevices in the stone wall; others he takes into his hole underground, where his cousin, the saucy chipmunk, stores all of _his_ savings.

Notice how the pretty little animal uses his bushy tail as he scampers along a branch. Do you see that he holds it stretched out behind him, and keeps on turning it slightly first to one side and then to the other? The fact is that it helps him to keep his balance. When a man walks upon the tight rope he generally carries in his hands a long pole, which is weighted at each end with lead. Then if he feels that he is losing his balance, he can almost always recover it again by tilting up his pole. The squirrel's tail serves _him_ as a sort of balancing-pole, and by turning it a little bit to one side, or a little bit to the other, he can run along the slenderest branches at full speed without any danger of falling.

Everywhere we go we hear the whirring of grasshoppers, the chirping of black crickets, and the shrill declarations of the katydids. A blind man who could not see the scarlet of the maples, the deep crimson and purple of sumachs, the pepperidge and the blackberry thickets, or the golden glow in the birches as the sunlight strikes through them, would know the season of the year by the sounds.

How do the insects make their noise--for one can hardly call it singing? That will be a good subject for you to look up in your books. The air is filled with the droning and humming of other insects; how are these sounds produced?

We notice the insect-noises more, perhaps, because other animals are so quiet. It is rare to hear the croak of a frog, or the piping of a tree-toad or the note of a bird. What has become of the birds? When we see a few they are in flocks, and seem very intent on traveling somewhere. The truth is they are gathering in companies and journeying away to the south, where winter, with its cold and snow and hunger, cannot follow them. Next spring they will come back again, to spend the summer with us.

Only those birds remain which can live upon seeds, or pick up rough fare along the sea-shore. A band of small winged friends are flitting about among the weeds ahead of us. Do you not know them? Look closely. Aren't the canary-like form and black wings familiar? You would say they were goldfinches if they were more yellow, wouldn't you? Now you see that that is what they are, but in an olive dress. The fact is that all birds molt their feathers twice a year. In spring the new feathers come out in bright colors, and in autumn there worn gay coats are lost, and feathers of duller hue take their place. Thus the brilliant yellow and black goldfinch of summer becomes a quiet Quaker in winter. Such a change is very advantageous to the birds--how, you may study out for yourselves.

Butterflies are scarce, too, but these have died, not run away, as the birds are doing. One sees a good many sluggish caterpillars, however; and sharp eyes may begin to find cocoons hanging from the bushes, or tucked into crevices of bark, or plastered against rocks and the boards of old fences. If you were to keep account of all the different kinds you could find, you would soon have a long list; and if you were to learn how to keep them properly and care for the butterflies and moths which will come out of them in the spring, you could start an admirable cabinet.

Here is a patch of milkweed. Examine each plant thoroughly because there may be a gift for you hidden among the leaves. You have found "something pretty," you say? What is it like? "Like a green thimble, with rows of gold buttons on it." That is a pretty accurate description; only your thimble is closed at the top, where it hangs by a short thread, and it is heavy and alive, for it is the lovely chrysalis of the milkweed butterfly. Next summer you must learn the appearance of that species, which you can easily do, for it is one of our largest and commonest ones.

Where the milkweeds grow you are pretty sure to see also masses of goldenrod, and towering high above them the great, flowering pillars of joepye-weed. Such clumps are good hunting-places for autumnal insects. There gather the soldier-beetles, brilliant in uniforms of yellow and black. They are sometimes so numerous as to bend down the plants by their weight, and are in constant motion, crawling about the blossoms, or flying from spray to spray. Here, too, come locust-boring beetles, black with a line of yellow V's on the back, whose eggs are laid in the soft inner bark of locust-trees; and fat short-winged blister-beetles, or oil-beetles, which leave such a bad odor on the hands when touched. This is due to an acrid oil which oozes out of the joints of the beetle's legs when it is handled and thinks itself in danger. It is a protection, for it both smells and tastes so nasty that no bird will ever attempt to eat an oil-beetle. And its body is so very big because it lays such an enormous number of eggs. How many eggs do you think an oil-beetle will lay? Why, something like thirty thousand! She lays them in batches in little holes in the ground, and a few days afterward a tiny little grub hatches out of each egg, and begins to hunt about for some flower that bees are likely to visit. When it finds one, it climbs up the stem, hides among the petals, and waits. Then as soon as a bee settles upon the flower it springs upon her and clings to her hairy body. The bee is very busy collecting nectar and pollen, and the grub is very tiny; so she never seems to notice that the long-legged little creature is clinging to her, and carries it back with her to her nest. Then the grub lets go, and proceeds to eat all the "bee-bread" which the bee had stored up so carefully for her own little ones.

How is it that all the trees, bushes, and plants are covered with threads of spider's silk, which often annoys us by getting on our hands or faces? Let us help you to an answer. This is the time of year when spiders are most numerous and most active; and many a spider trails behind it a thread of gossamer wherever it goes, and leaves it there. On many of the plants, bushes, trees, and fences you may see, if you look closely, very small spiders resting. Those little spiders have been taking a journey through the air--a sort of balloon trip. During the summer a number of spiders, all living near one another, had big families--a hundred or more in each. Perhaps you noticed in July and August spiders dragging about large white bundles: they were packets of eggs from which the young hatched. So many coming into the world together made it difficult to find food. So, one by one, the little spiders climbed low bushes or tall plants, and perched themselves on the tips of the topmost leaves. Then each poured out from the end of its body a slender thread of silk, which floated straight up in the warm air rising from the heated ground.

At last each little spider had seven or eight feet of thread rising up into the air above it. Then suddenly it loosed its hold of the leaf, and mounted into the air at the end of its own thread, higher, and higher, and higher, till it had risen several hundreds of feet into the air. Then it met a gentle breeze traveling slowly overhead, and traveled along with it, mile after mile, still resting on its thread. And when it wanted to come down, all that it had to do was to roll up the thread till there was not quite enough left to support it, and so it came floating gently down to the ground below. Then, having no more use for the thread, it broke loose from it and left it lying like a fallen telegraph wire across the tops of the bushes and fences and other things, where our faces brush against it.

What a pretty green fly this is sitting upon the fence, with delicate gauzy wings looking like the most delicate lacework!

Yes, that is a lacewing fly. Just notice what wonderful eyes it has. They look like little globes of crimson fire, and it is quite difficult to believe that a tiny lamp is not alight inside the head. This fly lays its eggs in a most curious way. Settling on a twig, she pours out a drop of a kind of thick gum from the end of her body. Then, jerking her body suddenly upward, she draws out this gum into a slender thread, which hardens as soon as it comes into contact with the air; and just as she lets go she fastens an egg to the tip. She then lays another egg in the same manner, and then another, and then another, and so she goes on till she has laid quite a little cluster of eggs--perhaps ninety or a hundred altogether. You would not think that they were eggs if you were to see them. You would be almost sure to think that the little cluster was a tuft of moss. Indeed, for a great many years even botanists thought that these eggs were a kind of moss, and put pictures of them in books of botany accordingly!

Look at these odd little black and white spiders. How jerkily they run; never moving more than an inch or so at a time, then stopping to rest, and then generally darting off again in a different direction. They are hunting-spiders, and are so called because they hunt for insects instead of trying to catch them in a web. You may see one of these spiders "stalking" a fly very much as a cat creeps up to a bird, and then suddenly springing upon it and leaping into the air with its victim firm in its grip.

Slowly the days grow shorter, the rains come more frequently, flowers wither, and the herbage shrivels. Insects die off, the birds one by one disappear quietly, or gather in flocks to journey southward, and the woods grow quiet and gray.

IV

WINTER

As we look out of the window on a landscape of snow, or of half-bare earth, frozen roads, and leafless trees, the world seems lifeless. But one who starts out for a walk, anxious to discover whether all nature is really dead, will soon find that it is very much alive, though much of it is buried in slumber. Let us test it.

As we take the well-accustomed path we cannot but contrast the bareness and silence with the activity and color and cheerful noise about us when a few weeks ago we strolled this way. The thought saddens and discourages us a little, when suddenly there comes to our ears

"_Chick-chick-a-dee-dee!_ Saucy note, Out of sound heart and merry throat, As if it said: 'Good day, good sir! Fine afternoon, old passenger! Happy to meet you in these places Where January brings few faces.'"

There is the singer--half a dozen of them in fact--fluffy little gray, black-capped birds not much bigger than a man's thumb, dodging busily about the limbs of that old apple-tree, swinging with desperate clutch at the tip of a twig, hanging head downward to get at a morsel on the under side of the bough, and chattering all the time as though cold weather were no hardship at all.

What do they find to eat? Keep your eyes on one, and see if you cannot guess. He is pecking here and there at the bark, and swallowing something so minute we cannot recognize it. But do you not remember how, last summer, we watched the procession of ants climbing this very tree to get honey from a "herd" of aphids on the branches? Those bark-lice are still there, each hidden under a sort of scale, like a winter blanket; and it is these that the chickadees are pulling off and eating. It takes a great many of them to make a meal, and the birds must keep very busy. Perhaps that is one reason why they seem so happy. A busy person is usually a cheerful one.

When you meet a winter group of these merry tomtits it is well to wait quietly for a little while, since you are pretty sure to find others following them. There! do you hear that sharp tapping? Turn your head and you will see a small woodpecker with its checkered black and white coat, and a broad white stripe down the back, hewing away at the thick bark of that oak. He is tremendously in earnest, and let us hope he finds a good fat grub.

Gliding down the next tree-trunk comes something which for an instant we take for a mouse--it is so bluish and furtive; but it is a bird--a nuthatch--which has a straight slender bill almost like a woodpecker's, and which digs into the cracks and crannies for eggs and hiding grubs of small insects, now and then smashing a thin-shelled acorn for the wormy meal it contains, or tearing to pieces the fuzzy cocoon of a tussock-moth. It has an odd habit of working almost always head downward, and now and then lifts its head and squeaks out a sharp _nee-nee-nee_, as though it said "Never-mind-me. 'Tain't cold!"

Quite likely on the next tree a brown creeper--sedate brown little lady of a bird--is gliding about the trunk, very daintily picking and searching with her long slender and curving beak for similar hidden food. She is a dear little creature.

Even prettier are the kinglets that often form one of this little company of winter workers. They are the smallest of all American birds except the hummers, and are olive green with tiny crowns of gold and rubies, as one might say. They have the activity and nimbleness of the chickadees, and toward spring cheer us with a brilliant song. These lovely pygmies are cousins of the wrens; and one may sometimes see flitting about the brush a real wren, which in summer flies away to the far north, letting us hear for a few days in March, before he leaves, specimens of the exquisite song with which he will make the Canadian woods ring when next June he meets his mate and builds his nest among the great pines and spruces.

Most of our birds, you know, flee southward, when cold weather approaches, but some, like the crow, many birds of prey, as hawks and owls, some game-birds, such as Bob White and the grouse, several of the seed-eating sparrow tribe, and some others, such as the little fellows we have been watching, stay with us, because they find plenty of food. If we should go out every day of the winter we could make a long list of these by the time All Fools' day came around. To it might be added a goodly list of birds whose proper home is in Northern Canada, but which in midwinter come south to a country which is less snowy if not less cold. The snowbirds, with their satiny feet and ivory bills, dressed like gentlemen in lead-colored coats and white vests, to which you toss crumbs from the breakfast table every morning, are in this class. Doubtless we shall see others as we turn down the wooded lane that leads to the creek.

Here among these bushes is a good place to look for cocoons of moths and butterflies. One is pretty sure to see at once a few of those of the big Promethea moth folded within a large leaf, the stem of which is lashed by silk threads to its twig so that it will not fall or be blown away. Very likely on the same bush will hang a similar big cocoon, but this one fastened all along the under side of the twig, so that it is hammock-shaped. Search about among the heaped-up leaves beneath the bush, and you may find the cocoons of the great Polyphemus silkworm-moth and of that exquisite pale-green luna-moth which flits like a ghost to our lighted windows on summer nights.

But these are the giants of their race. Hundreds of smaller cocoons and chrysalids--papery, fuzzy, leathery, or naked and varnished to keep out the damp, may be discovered in the crevices of the old fence, upon and beneath the rough bark of trees, rolled up in leaves little and big, and buried in the ground, where the moles hunt for them when the ground is not frozen too hard, and the skunks dig them up.

How about the moles and the skunks? Well, the moles are by no means as active as in summer, though they move around somewhat under the frozen layer of top-soil, in search of the earthworms which have been driven deep down by the frost. As for the skunks, they, like the woodchucks, the chipmunks, and the red squirrels, are deeply sleeping in underground beds; but plenty of four-foots are wide awake. See how that gray squirrel is making the snow fly as he paws his way down to the nut he buried three months ago! Only the tip of the plume of his tail waves above the drift.

Do you see that double row of holes punched in the snow? Every country boy knows them as the track of a rabbit, and would tell you how fast the rabbit was going. But what embroidered on the glistening snow-sheet this lovely chain that extends wavily from this tree to that stone wall? A weasel. Little cares he for cold, in his white ermine coat; and many's the careless sparrow, and snugly tucked-in mouse that falls to his quick spring and sharp white teeth. The weasel's nearest cousin, the mink, is working for his living, too, these winter days, haunting the warm spring-holes in hope of catching eels or other fish. Perhaps we shall see some signs of his work along the creek.

And now we have come to the end of the last of our rambles. But don't think that we have seen nearly all that there is to be seen. If we had been able to spend a little more time in the fields, or the lane, or the wood, or on the banks of the stream, we should have noticed a great many more animals and birds and reptiles and insects, quite as curious and quite as interesting as any of those which we have met with. And if we had taken a dozen rambles together instead of only four, each time we should have found fresh creatures to look at, and fresh marvels to wonder at, and fresh beauties to admire. For wherever we go nature always has something new to show us; and the world is full of wonderful sights for every one who has eyes to see.

NATURE-STUDY AT THE SEASIDE

Introduction

Many very curious and interesting creatures are to be found on the seashore, and we dare say you would like to know something about them. So let us take, in thought, four rambles along the shore together. First we will go for a stroll on the sandy beach, which is left quite dry for some little time when the tide goes down. Next, we will pay a visit to the stretches of mud just above low-tide mark, left bare in the coves for perhaps a couple of hours twice each day. For our third ramble we will wander about among the rocks, and examine the creatures which are crawling about on them, or burrowing into them, or hiding underneath the great masses of seaweed with which they are covered. And then, lastly, we will search in the pools which lie between the rocks, where we shall probably find some of the most interesting animals of all.

We will suppose that these walks are on our Atlantic coast, for we have not time now to explore the shores of the Pacific and describe its animals, many of which are very different from those of the Eastern coast.

I

ALONG THE SANDY BEACH

As all the coast of the United States south of New York, and Cape Cod and Long Island besides, are formed of soil and pebbles ground off the tops and sides of the Appalachian ranges of mountains, the ocean beaches and the bottom of the sea near shore are all of sand, constantly swept by currents, and moved by storms. On such a plain of shifting sand not many plants or animals can live save those which are able to swim or to bury themselves; and not nearly so long a list can be made as among the rocks which give root-hold and shelter, or where the bottom is muddy, as we shall see later; yet a walk will enable us to find a good many things about which you ought to know something.

Here, for instance, are a lot of shells, the hard outer coats of the soft boneless creatures we call mollusks, such as you know very well on land as snails. When you have filled your little basket, if we asked you to sort them into two kinds, you would be almost sure to put those which consist of two pieces, attached together, into one pile, and those which are in one solid piece, and more or less twisted like a snail, into the other. This would mark a real division, for the first heap would have the clam-like mollusks which we call bivalves, and the second would have those coiled gastropod mollusks that we may call sea-snails.

The bivalves scattered along the beach are all dead and mostly broken, for they have been washed up from muddy places; but many of the sea-snails may be found alive and belong here on the sand, and so we may look first at them.

Here is a big one to begin with which the southern fishermen call a conch and the northern oystermen a winkle. It is shaped like a pear, and pushing out of its shell a very tough muscular part of its body called the foot, it plows along in the sand, or even burrows into it, small end first, searching for food, which consists of animal matter, either dead or alive. It finds this by its sense of smell, and when it comes to it, thrusts out of its head, near the forward end of the foot, a long ribbon-like tongue, covered with hundreds of minute flinty teeth, and rasps away the flesh. Winkles are numerous everywhere and are of great service in devouring dead fish, etc., which would pollute the water; but they also eat a great quantity of oysters, as we shall see presently. You will find two kinds, and should note how their shells differ.

Very likely you will find among the long rows of dead eel-grass and drift-stuff marking the reach of high tides a twisted string of most curious objects, each about as big as a cent, feeling as if made of yellow paper and strung together like a necklace on a stiff cord. These are the eggs of a conch, or more truly, the egg-cases, for in each cent-like capsule was placed an egg. You can prove it by opening some of them. In the dry ones you will probably find only dead young shells, hardly bigger than pin-heads, which have hatched from the eggs; but now and then you may pick up a soft and elastic set, and in these, which are alive, or have only lately been torn from the weeds in deep water and thrown upon the beach, you will find much larger baby conchs, which by and by would have found a way out and begun to travel about.

We have already picked up several different sorts of slender, twisted sea-snails of small size, and a few as big as a walnut and almost as round, save for the circular opening out of which the animal pushes its foot. His name is Natica, and he is one of the worst foes of the clam, whose shell he bores. Here, half buried in the wet sand at the edge of the gentle surf, is a living one, and we can see the grooved trail behind him showing where he has traveled. We will pick him up, and see how hastily he shrinks back into the armor of his shell, and shuts his door with a plate growing upon the tip-end of his foot. All these sea-snails have such a plate, sometimes thin and horny like this one, sometimes thick and shell-like; and if you try to pry it away you will have to tear it to pieces, for the frightened animal will not let go its strong hold. He knows better than to open his door and let you pick him out. Even if you did you would have to tear his body out piecemeal, for he would by no means uncoil it from around the central post of his house and let himself be dragged out whole. This door is a good protection, then, against the claws of crabs and the nibbling teeth of fishes and various small parasites which would like to get at him. It is called an operculum.

Just lift up some of that seaweed and stuff which the waves have piled up. Why, the sand underneath it is simply alive with sandhoppers, besides various jumping and crawling insects, sand-bugs, spiders, etc. But the sandhoppers are most numerous--there must be a hundred, all skipping about so actively that it is quite difficult to follow their movements. They were feeding upon the seaweed, and their sharp little jaws are so powerful that if you were to tie up a few sandhoppers in your handkerchief and carry them home, you would be almost sure to find that they had nibbled a number of little holes in it by the time that you got there! But surely such little creatures as sandhoppers cannot do very much good, even by eating decaying seaweed. Ah! but there are so many of them! Wherever the shore is sandy they live in thousands, and even in millions. If you walk along the edge of the sea, sometimes, when the tide is rising, you will see them skipping about in such vast numbers that the air looks as if it were filled with a kind of mist for a foot or eighteen inches from the ground. And though many of the shore-birds feed upon them, and some of the land-birds do so, too, and the shore-crabs eat a very great many, yet their numbers never seem to grow less.

These sandhoppers are small cousins of the crabs with which we shall get acquainted when we go to the mud-flat; and a search would find many others, such as beach-fleas of various kinds. Here and there are strange grooves, and--look! one of them is growing longer under our very eyes. Dig away the sand just ahead of it, and see what you can find. There it is--a small ivory-like creature, about twice as big as a pumpkin-seed. It is a sand-bug, or hippa, and it burrows along just under the surface, searching for minute particles of food among the grains and letting the sand fall in behind it, for it does not mean to make a tunnel.

One of the waste objects you tossed aside was a piece of wood which the waves have flung up, and which no doubt once formed part of a wrecked vessel.

"And I don't wonder!" some one exclaims, "if all the timbers were as rotten as that!"

The bit of timber is certainly ruined--but what has happened to it? It is full of long round burrows, each about big enough to admit a lead-pencil, and so close together that the walls between them are very little thicker than paper; and every burrow seems to be lined with a kind of glaze.

That is the work of a curious creature known the world over as the ship-worm, which often does a great deal of mischief by burrowing into the hulls of ships and the timbers supporting wharfs and harbor-side buildings. It has a soft round body no bigger than a piece of stout string, and often nearly a foot in length. But it is really a shell-bearing mollusk, like the cockle and the clam. And if you were to look closely at the fore end of its body you would see its bivalve shells, although they are so very small that they might easily be mistaken for jaws.

When first this animal hatches from the egg it is not in the least like its parents. It is just a little round-bodied creature covered almost all over with hairs, by waving which up and down it manages to swim about in the water. But it does not keep its shape very long, for if you were to look at it about thirty-six hours later you would find that it was oval instead of round. Twenty-four hours later still it would be almost triangular, while next day it would be almost round again. And so it would go on changing its form day after day, till at last it fastened itself down by its fleshy foot to a piece of sunken timber and began to burrow in it. And then at last it would take the form of its parents. The birth and growth of most of the bivalves is similar to this; and it must be remembered that these changing larval forms are hardly large enough to see.

Another timber-destroyer all along the New England coast is the gribble, a crustacean related to the sandhoppers, which is not bigger than a grain of wheat, and looks like a pill-bug. It devours wood wherever it finds it under water, and will gradually honeycomb and weaken until they fall to pieces the bases of piles, boat-stairs, and other timbers under water which are not sheathed with copper or filled with creosote. Therefore it is much hated.

A sandy beach is not the place for crabs in general, but there is one kind which we ought to find here. There is one now, but one might wager something that you can't discover it in its hiding-place unless shown to you. Do you see those two little round objects on short stems sticking half an inch out of the sand by that old winkle-shell? Yes? Well, please go and get one or both of them. What! is it alive? some sort of crab, buried in the sand? All right--pick it up, but look out it doesn't nip you! Those claws are powerful, for with them the crabs must seize and firmly hold struggling, slippery fish and other animals, until it can subdue and eat them. Notice how the hind legs are flattened into strong paddles to enable it to swim swiftly upon its prey. In spite of these fierce qualities we call this one a lady-crab, because of its richly ornamented costume--greenish yellow profusely marked with purple rings. It spends most of its time crawling or swimming in the sea where the bottom is sandy and the water shallow, but now and then comes ashore and buries itself in the dry sand, all but its stalked eyes, as we found this one.

A smaller, lighter-colored, and more square-bodied cousin of this crustacean, called the ghost-crab, is very common on southern beaches, where it digs slanting burrows deeply into the sand. Prof. A. G. Mayer tells us that it is a scavenger, feeding on dead animals, and also catching and eating beach-fleas. It is at night that they are most active. "As they flit rapidly about in the moonlight their popular name of ghost-crab seems remarkably appropriate. As one approaches they dash off with great rapidity, and will often rush into the water, although the gray snappers are swimming close along the shore in order to devour them."

What have you found now? It appears to be a horseshoe-shaped skillet, or frying-pan, made of brown parchment, with a long spike loosely hinged to one side for a handle, and a big crab lying on its back in the pan. No wonder you are surprised. The first white men who came to this country were equally so, for nothing of the sort is to be seen in any other part of the world, except in the Malayan islands. If we search we are likely to find one alive and creeping about, and then we shall see that the skillet is a broad shield covering the back of an animal, and that what we thought was the crab inside it, is its body and legs. When you come to study natural history more deeply you will learn many very interesting things about this strange inhabitant of our beaches, which is known as a horseshoe-crab, or king-crab, and also as limulus. It is the sole remnant of a great tribe of sea-animals called trilobites, which became extinct ages ago.

One more curiosity must be mentioned before we quit this first short walk upon the open beach--what the fishermen call the mermaid's-purse, of which, see, you have found several.

It is an egg, but you never would have suspected it, would you? Examine it. It is about two inches long, and made of a hard, black, leathery substance, and at each of the four corners there is a little projection about an inch in length. It is the empty egg of a skate--a fish of the shark tribe with a broad, flat body and a long whip-like tail--from which one of these curious fishes has just escaped. How do you think it got out of the egg when the time came for it to be hatched? Just look at this empty case, and you will see. At one end there is a slit running across it almost from one side to the other, made in such a manner that the little fish could easily push its way out, while none of its enemies could push their way in. So the baby skate lay in its cradle in safety till the time came for it to pass out into the sea.

But here is an egg made in just the same way, with one little difference. Instead of having a short straight projection at each corner, it has a long, coiled, twisted one, much like the tendril of a grapevine. That is the egg of one of the small sharks called dogfish, which are so called because they swim about in parties or packs of fifty or sixty together, driving herring and other fishes before them, as dogs drive deer. The skin of a dogfish is as rough as a piece of sandpaper.

When the eggs of this fish are first laid, the twisted projections at the ends coil themselves round the stems of weeds growing at the bottom of the sea, and hold them so firmly that they cannot be washed away; and at each end there is a small hole, so that a current of water may always flow through this egg-case and over the little fish inside--something of just as much importance to it as is a supply of air to a land-baby.

II

SEARCHING THE SHORE AT LOW TIDE

The shore of the eastern United States, at least south of New York, is formed of a line of long narrow islets whose outer beaches, and the sea-floor for miles out, are pure sand. They support very little life, as has been said. Behind them, however, are shallow bays and sounds, in which the water, though salt, is usually warm and still; mud gathers upon the sand, and eel-grass and other water-weeds grow in abundance. Here is excellent ground for naturalists, old or young, and in a single walk you can discover enough to surprise you greatly. We must go when the tide is low, and it will be a good idea to take our rubber boots, so that we may not be afraid of the wet mud. We will also take a small spade or strong trowel, and some boxes and bottles.

What a lot of clam-shells are lying about the shore! There are two kinds, the soft clam and the hard clam; but none of them are alive.

How is this? We have already learned, you will remember, that the clams are bivalves; that is, the shell is in two pieces, hinged together by an elastic ligament over the back, and covering each side of the animal. The soft body is attached to each shell by a strong muscle, by which the creature can pull the shells tight together, and so cover itself completely. When it wishes, however, it lets the shells spring open somewhat, so that it may put out from between their lower edges its muscular "foot," and perhaps move about, while out of the front end it stretches a double-barreled tube, called its siphon. Down one of the tubes is sucked a stream of water which not only bathes the animal's gills, or breathing organs, but carries minute floating particles of food into its stomach, after which the waste water is forced out of the other tube.

Now you will understand what we shall see, and are ready for the answer to our question. You never find live clams crawling about the sand, because they live buried in the mud.

Now let us put on our boots and look about on the surface of the wet mud. Do you see ahead of us those little jets of water come spouting up into the air as if squirted out of tiny syringes? Every one of these little jets is thrown up by a soft clam, which lies perhaps several inches deep in the mud, with its siphon stretched up to the surface and held full of water, waiting for the tide to come in and refresh it. When it feels the jarring of our footsteps it squirts the water out; and you must dig deep and fast if you want to catch it. This is what those men are doing out there on the flat--digging out clams with long spades, and filling their baskets for market. Thousands of little ones lie in the mud, not yet big enough to eat.

The soft clam is a shapeless sort of mollusk, with a thin chalky shell, not at all pretty; but the hard clam, or quahog, is thick-shelled and regular in outline; and in an end-on view takes the shape of an ace of hearts, like the Venus-shell, or the cockle, which is so commonly eaten in Europe. This species likes much deeper water than the soft clam, and is gathered mostly from boats, by a kind of rake; but we shall no doubt find a few up here. Do you see that scratch in the mud? It looks like a trail, and there at the end is the traveler himself, standing upright in the mud like a half-buried wedge.

This shows another difference between the two clams; for while the soft clams and their relatives, such as the pretty razor-fish, and the "old maid" of English bays, never leave the burrow where they begin life, the quahogs slowly wander about all the time. As for the scallops, they fairly skip and jump.

What are scallops? Well, we shall hardly see much of them, for they live in deep water; but their half-shells are to be seen cast up everywhere, for they also are bivalves. Our common ones are usually about the size of a silver dollar, and fan-shaped, the thin shell ribbed like the sticks of a fan, and the margin crinkled, and they are variously colored, but mostly in tints of reddish and yellow.

Several small bivalves and sea-snails may be added to our collection from this uncovered bay-bottom, and here and there spaces are fairly sprinkled with little blackish fellows about the size of hazelnuts. When we have gathered a handful we shall find we can sort out three or four kinds.

A very curious denizen of the tide-flats of our Southern States is the pinna, a large bivalve with thin horny shells shaped like a slightly opened fan, which lies deeply buried, point down. The edges of its shell come just at the surface, and are exceedingly sharp, so that barefooted persons have to be very careful how they step where pinnas are common, as on the Gulf coast of Florida, and it is no wonder the people there call them razor-fish. Lying there in the mud, with its shells parted, and a current of water always sucking down what we may call its throat, it forms a regular trap for little fishes and other small creatures. The instant one swims between the shells, they close and the unfortunate curiosity-seeker finds himself in a prison from which there is no escape.

When a young pinna settles down in its place it at once anchors itself to some rock or fixed thing below it by throwing out from near its lower, narrow end a bunch of very strong threads, which hold it down so firmly that it takes a very hard pull to tear them away. This anchor-cable is called a byssus.

A short distance from us a narrow stream wriggles through the salt marsh, and we can get into a rough little boat and paddle down toward that old wharf whose weedy piles are covered with interesting things, which we may examine now that the ebbing tide has left them uncovered for a few hours. The peaty banks, with their growth of harsh salt-grass and algæ, will keep our eyes busy as we float along the black and winding creek.

Now we shall get acquainted with some of the crabs. Look sharply down into the water and you will see the large "blue" crabs which we buy in the market, and eat, swimming near the bottom or crawling over the mud near the banks. There is one, now. He doesn't look very blue, nor very appetizing, does he? His back is brown and muddy, to be sure; but his big claws and lower plates have much more blue upon them than has any of the other large crabs, and so he gets the distinguishing name.

But, you say, you have heard of "hard-shell" and "soft-shell" crabs, and want to know the difference? It is simply a difference of condition. If you will turn to page 397, you will find described that extraordinary process by which crabs grow, by throwing off their stiff old skins and expanding to fill the elastic new one which has formed underneath. Before this change, the creature is a "hard-shell" in fishermen's language, and just afterward, when he is large and tender, he is naturally a "soft-shell"; and then is the time to eat him.

Notice how the black masses of peat along the banks are honeycombed with holes, as if somebody had been pushing down the point of his umbrella. They are the homes of little fiddler-crabs, which scuttle into them by the hundred as we approach, and then creep up to peer out after we have passed by, and make sure it is safe to go abroad again. In other holes live two other sorts of burrowing crabs. One is the little mud-crab (_Panopæus_), which is a peaceful cousin of the fiddler; and the other is the sand-crab (_Ocypoda_) whose peculiarity it is to be perfectly sand-colored, so that it is almost impossible to see him until he moves; consequently he is commonly found only in the sandy places.

As we float nearer to the mouth of our winding creek, we begin to notice bunches of mussel-shells, clinging closer to each other than grapes in a bunch; and when we try to pick one up we find it quite immovable. In fact, they are anchored to the roots of the grasses, and to each other, by a bunch of byssus threads from each mussel, like those of the pinna; and these threads are so strong that they can hold the mussels firm against the beating of the waves, so that a shore which is thickly covered with mussels is safe from wearing away. You may see an example of this in the tideway at the mouth of this very creek, and masses of mussels strengthen the supports of that wharf we are approaching. If you were to go near the town of Bideford, England, you would see a bridge of twenty-four arches, which runs across the Torridge River close to the place where it joins the Taw. Now that bridge is held together by clusters of mussels! The force of the stream is so great, that if mortar is used to repair the bridge it is very soon washed away. So from time to time large boat-loads of mussels are taken to the spot and shot into the water, and they fasten themselves so firmly to the bridge by means of their byssus threads, that they actually hold together the stones of which it is built!

These binding mussels are mostly of the smooth, dark-blue sort which are found on both sides of the Atlantic, and in Europe are gathered and eaten. When our people become a little wiser and more economical, we also will take advantage of this great stock of excellent food right at our doors.

But in the bunches which are scratching the side of the boat as we glide along close to the bank are some which are much larger, though smooth, like the edible mussels. They are an American species. Then here and there in peat you may see a sort whose shell is rough, with ridges spreading out toward the large end, and these you may call horse-mussels.

Now we have got down to the boat-landing toward which we have been lazily drifting, and we will twist the chain around one of the piles that support it, and stop long enough to take a look at one of them. Most of the time each pile is under water, and therefore is overgrown with a thick "fur" of plants and animals.

You will see that most of this fur consists of seaweeds, but their leaves are often the resting-place of several sorts of lowly animals. Indeed, you must look sharp to make sure whether some of the feathery tufts that droop from a dank old post, or spray out so beautifully in the ripples at its foot, are plants or animals. We will not talk about that just now, but wait till we take our excursion to the rocky shore, where we shall find barnacles and corallines and sea-mats and polyps bigger and better than here.

But do you see between those green fronds that roundish yellow object about as big as a filbert? Touch it gently. Did you see tiny jets of water squirt out of two little nozzles on its surface? That gives it the name of sea-squirt. Into one of the nozzles, when the tide comes over it, is constantly sucked a current of sea-water which passes into a stomach-like cavity, where the minute particles of food in the water are caught and digested; then the water passes on through another cavity where the blood receives its oxygen, as in our lungs or a crab's or fish's gills, and then rushes out. So this little object is a real animal, with heart, blood, stomach, and something in the way of nerves--enough, at any rate, to feel your touch, shrink, and squirt out all the water in its bag-like body.

There are a good many kinds and forms of these ascidians, as naturalists call them, some larger, some waving about on the summit of stalks like lily-buds, and some clustered into colonies grown together, which form bands around the stems of plants, or make masses called "sea-pork" by the fishermen, or float in chains, by millions, on the surface of the open sea.

Here, too, are small red and yellow sponges; some coarse little sea-anemones, etc.; and wandering over the whole, feeding upon one or another of these, and cleaning the polyps and polyzoans off the algæ, are a sort of marine daddy-long-legs, called no-body crabs, because they seem all legs and look crab-like.

It isn't very sweet-smelling under this damp old wharf, where the rising tide is beginning to bathe the piles, and one after another plants and animals are expanding as they feel the refreshment of the water around them; and we will move away as soon as we have dug a few things out of the mud, soon be hidden by the tide.

Let us run the bow of our boat up on that soft black slope, and see what we can find by leaning over the side. Just look at this hairy object, for instance, which has been left by the retreating waves. It seems like a big brown slug covered with bristles and is not very pleasant to handle; but you needn't be afraid of it, and you mustn't be squeamish. Just dip up some water in that pail, and rinse it till you have washed every scrap of mud from its bristly coat, and then look at it in the sunlight. Do you think it is dull and dingy now? Did you ever see a more beautiful creature? This animal is called the sea-mouse, although really it is a kind of sea-worm and if you will turn back to page 429 you will find it described. The reason why its coat is always so dirty is that the bristly hairs which cover it act as a sort of filter, and strain out the mud from the water which is passing to the gills. But these hairs have another use as well. Each one is really a sort of slender spear, with a barbed tip, the edges being set with a number of sharp little points, all directed backward, forming a capital protection from such creatures as the fishes, a great many of which would be glad to feed upon sea-mice if it were not for their coating of spines.

Do you see those twisted little coils of muddy sand scattered about on the mud? Those are the casts of lugworms, which are made in the same way as the casts of earthworms seen in our garden-paths on damp mornings; in fact, these lugs are just marine earthworms (see page 427), and like them eat their way down into the mud, swallowing mouthful after mouthful for the sake of nourishing particles in it, and then voiding the useless remainder.

Perhaps you wonder how it is that the burrows of the lugworms remain open. Why doesn't the mud close in behind the animal? The fact is that the worm is always pouring out from its skin a sticky slime which quickly becomes quite hard and firm. And this binds the sandy mud together as the worm forces its way down, and forms a kind of lining to its burrow, just like the brickwork with which we line our railway tunnels.

You would scarcely suspect what interesting and often beautiful worms lie buried in the mud or muddy sand of sea-beaches and salt marshes. They occur elsewhere, too, as upon weedy rocks, while a great many kinds dwell upon or within the bodies or coverings of other animals, from whales to periwinkles and crabs.

Most of the beach-worms belong to the highest class of the tribe, called annelids because their bodies are made up of ring-like segments (a little ring in Latin is _annellus_), as you can easily see by examining one of the angleworms you dig in the garden for fish-bait. The red lugworm, or "red thread," as it is often called, is another plain example of this structure.

Digging down by low-water mark we are likely to unearth one or more of the ribbon-worms which, when they are large, seem rather terrible. Their bodies are flat, so that when they swim they move through the water like a floating ribbon, and they have been found five or ten feet long and as wide as your palm. Such big ones are rare, however, and we are more likely to have to deal with one two or three feet long and less than an inch broad. They are active creatures, burrowing into and through the mud in search of other worms upon which they feed, and which they seize by thrusting out a sticky proboscis. There is also a smaller one, pink in color, while the bigger species is yellowish.

Though we may not dig up a ribbon, we are pretty sure to turn out a nereis, or clam-worm, as the fishermen call it--a reddish creature a foot or two long, looking like a centipede, for there is a pair of minute feet on each ring, and every foot is feathered with a gill. This also is a ravenous enemy of all other worms or animals it can overcome; and young clams, limpets, starfish, and other protected creatures must be thankful for their armor when it comes crawling near them. Its rich green and salmon coat has no charm in their eyes, you may be sure. But the nereis itself must have its fears, for it is not only hunted by ribbon-worms, by a big active annelid called "four-jawed," and by winkles and dog-whelks, but is well liked by various fishes; and, last misfortune of all, it is constantly sought by fishermen for bait. In spite of all this, clam-worms of all kinds remain immensely numerous all along the coast. On calm summer nights they leave their burrows, swim up to the surface at high tide, and cast out vast numbers of eggs, from which presently hatch little pear-shaped larvæ, which swim about a short time, when the few that have survived settle down, change to the worm-like form, and burrow into the mud.

When we come to explore the rocky places, and peer into the still pools left by the ebb-tide among the reefs and boulders, we shall make the acquaintance of some other worms that display themselves in such places as in a natural aquarium.

III

ON THE ROCKY LEDGES

There are practically no rocks on our Southeastern coast, so that we must imagine ourselves now somewhere in New England--let us say on the southern shore of Rhode Island. All along the north side of Long Island Sound, about Buzzards and Narragansett bays, and then from Boston Harbor right up to Labrador, the shore is rock, with many headlands, reefs, and islets, separated by shallow coves or by swift tidal runways. This is good hunting-ground for the seaside naturalist, and one visit to the space left uncovered at low tide will be no more than a glance at what might easily keep us busy and interested a whole summer through.

As the water ebbs away, the tops of the ledges and boulders emerge like the hairy heads of some sea-monsters, for they are mostly overgrown with long tresses of olive-brown rockweed and green ribbons of sea-cabbage, (_Ulva_), which trail, wet and shining, down their sides. Step carefully, for it is all extremely slippery. Do you hear that continual popping under your feet? That means that you are crushing the little bladder-like swellings strung like big beads on the stems of the rockweed. They are filled with air, and keep the long and heavy stems and leaves of the weed afloat, as you may see if you look down where it is swishing back and forth in the lapping waves. These plants must be exceedingly strong to resist the pulling and pounding of the surf in a storm; and their power to keep afloat by means of these gas-filled "bladders" is of assistance, not only in enabling them to hold together, but to form a breakwater which protects the rocks and ledges they cover from being beaten to pieces by the surf.

Underneath and upon these masses of seaweed hide a great quantity and variety of small plant and animal life, some of which we shall be able to find and study, though a large part of it requires more thorough work than we have time for, and the aid of a microscope.

But first let us look at some of the bare places, where there is no seaweed. Here is a black rock with white patches of rough little things growing upon it by the hundred. They are not mollusks, however, but rock-barnacles (see page 407), which English boys call acorn-shells. They are small and distant cousins of the crabs.

The story of these barnacles is a very curious one. When first they hatch from the eggs which older barnacles have cast out into the sea, they are not in the least like their parents, but are queer little round-bodied creatures, smaller than pin-heads, with six feathery legs by which they paddle about, one round black eye, and two feelers. Every two or three days they throw off their skins, as caterpillars do, and appear in the new ones which have formed underneath; and every time they do this they change their shape, so that sometimes they are round, and sometimes oblong, and sometimes almost triangular!

At last they reach their full size. Then they cling with their feelers to the first rock, log, or other hard thing they come to, and pour out a drop or two of a very strong cement, which hardens around them and fastens them firmly down. After this they never move again; but a day or two later they change their skins once more, and appear as perfect acorn-shells.

Now look at one of them carefully through this magnifying-glass. Do you see that there is a little hole in the top of the shell, which is made of several pieces? That is the hole through which the animal inside fishes for food. If you were to watch it when the rocks are thinly covered with water, you would see that it kept poking out a net-like scoop, and then drawing it in again. This net really consists of the hairy legs; and as they wave to and fro in the water they collect the tiny scraps of decaying matter on which the little creature feeds. They also bear the gills by which the barnacle refreshes its blood.

You must be very careful not to knock your hand against these shells when you are hunting about among the rocks, for their edges are so sharp that they cut almost like knives.

"Another sort of barnacle," you say you have found? No: there _are_ other sorts--the strange goose-barnacle, for instance, which attaches itself to the bottoms of ships--but what you have found is one of the limpets, and that is not a crustacean, but a gastropod mollusk. It is shaped like a tiny rough mountain, or rather like a volcano, for you see there is a hole in its summit; and we call it the keyhole limpet on account of the shape of that hole. Pick it up. Oh! you can't, eh? Of course not. Pull and push as hard as you like, you won't be able to move it, nor can the heaviest waves wash it off.

Would you like to know why?

Well, the reason is that a limpet clings to a rock by turning the whole lower surface of its body into one big sucker; it presses it tightly against the rock and then lifts the middle part. The consequence is that a chamber is formed in which there is nothing at all--no water, not even air; and, as happens when you lift a brick with a small leather sucker, the weight of the atmosphere presses down upon it so strongly that no force you can bring to bear will pull it off.

However, a limpet is not gripping the rock all the time with such vigor; he would literally be tired to death, and starved to death, too, if he didn't ease up most of the time. It is only when he is alarmed by a touch that he clamps down. If you want to get him free, just wait till he loosens up, then hit him a sudden sharp blow on one side with a stick or stone, and knock him off. Then you will be able to examine the soft body and see how he is built.

Limpets are vegetable-feeders, and when the water is still, or absent, they creep slowly about the rock, nibbling the tiny vegetation on its surface. Another interesting fact in limpet-life is told on page 421.

Another kind of limpet is very common on those rocky shores, which is shaped somewhat like a loose round-toed slipper or a French _sabot_. This is the slipper-limpet, or half-deck, as fishermen call it.

On the lower rocks near the water, and hidden in among the wet seaweeds, lie many small spiral gastropods which we call periwinkles. Two of the commonest kinds are littorinas, marked with fine lines and colors in various ways. Another, reddish with chestnut bands, is named _Lacuna_; and you may pick up several kinds of small blackish ones, such as _Bittium_, or of light-colored ones, as _Rissoa_, which is prettily mottled; while numerous in some places is the purple-shell or _Purpura_, which is interesting because it belongs to the European shores as well as to ours, and because from it the ancients gathered some of their purple dye, although another mollusk (the murex) furnished most of it. But in old times the coast people, both of old England and New England, obtained from this little mollusk an indelible violet ink with which to mark their clothes.

Would you like to see a little of this dye?

Very well, you can easily do so. Look! Hold the purpura over this sheet of white paper, and give the animal a little poke with the head of a pin. There! It has squirted out a drop of liquid upon the paper. It does not look much like purple dye, does it? It looks very much more like curdled milk. But lay it in the sunshine and notice what happens. Do you see? It is turning yellow. Now a blue tinge is creeping, as it were, into the yellow, and turning it to green. The blue gets stronger and stronger, till the green disappears. And at last a crimson tinge creeps into the blue, and turns it to purple.

Another curious thing about the purpura is the way in which it lays its eggs. It fastens them down to the surface of the rock by little stalks, so that they look like tiny egg-cups with eggs inside them; therefore when these eggs hatch, several little purpura come out of each cup.

All the small periwinkles feed upon the algæ, but with the purpura, which seems to live mainly on young barnacles, we come to a lot of flesh-eaters--small mollusks of prey, as we might say.

There are several spiral sorts, mostly from one to two inches long, whitish and heavily ribbed, which are sometimes called dog-whelks; but the worst one, which lives by thousands on the beds of planted oysters scattered all along the shore of Long Island Sound, is known to the oystermen as the drill, or borer. It is particularly fond of the flesh of oysters, and cares nothing for their shells, as it carries in its mouth a drilling instrument (see page 419) by which it can bore a round hole through the poor oyster's armor. In this way it destroys many thousands of dollars' worth of valuable oysters every year.

It was pretty certain we should find a starfish down near low-water mark, and here is a fine one.

Starfishes are among the oddest of sea-animals; for one reason, because they have so many legs. Perhaps you did not know they had any legs at all; certainly you can see none when you pick up a dead specimen on the beach. The fact is that a starfish keeps its legs inside its body, where there are a lot of organs protected by its hard, limy hide; and when it wants to use them it pokes them out through little holes on its under or grooved side, and fills them with water.

You would like to see its legs, no doubt. Very well; you shall. This starfish is still alive: we can easily see that, for when we pick it up its rays stand stiffly out; but if it were dead they would be quite soft and flabby, and would hang down. So we will put it into a shallow pool of clear sea-water, and see what happens. There! did you notice that it moved one of its rays? See, the one in front is being slowly pushed forward. Now the rays behind are being drawn up; and now that they have taken a fresh hold the front one is being pushed forward again. The starfish is really walking! What will it do when it comes to a stone? Why, walk over it! What will it do when it comes to rock? Why, climb up it! Now take the starfish out of the water. Turn it over on its back. There! do you see? On the lower surface of every ray are hundreds of little fleshy objects waving about in the air. Those are its "feet," or at least its means of walking; and each has a sort of cup at the end which acts as a sucker. By means of these the starfish can cling tightly to the surface of a stone. So by using first the little sucker-legs on one or two of its rays, and then those on the others, the starfish is able to crawl about quite easily.

The starfishes live upon animal food--mainly other mollusks, which they kill in a very curious manner. When, in crawling about, they come upon a whelk or clam or oyster, they creep over it and clasp it in their five arms in a murderous embrace from which there is no escape. Even if the creature can move off, its captor clings to it with its hundreds of tiny suckers, and rides along with it like that Old Man of the Sea in Sindbad's story.

Now if you look again at our specimen you will see on its under side, a small pit in the center of its body, closed by five points. This is the mouth, and the points are sharp. As soon as the starfish has a grip upon its victim the mouth opens and there is gradually pushed out a strong membrane which is the creature's great loose stomach. This envelops the animal, shell and all, or as much of it as possible, and soon begins actually to digest the flesh. When the meal is finished the starfish draws back its stomach and leaves only the empty shell of its prey.

These voracious starfish are a worse enemy to the cultivated oysters than are the drills; and, having an abundance of food on the thickly planted beds, they become extremely numerous, so that it costs the owners of the beds much money each year to gather them off the beds by means of a sort of great rake called the tangles. Otherwise the oysters would soon be wholly destroyed. The men used simply to tear to pieces what they caught and throw them overboard again; but they soon learned that this was worse than useless, because each half, or even a single arm, would not only go on living but would reproduce all the missing parts; so that in trying to kill one starfish they had brought to life two or perhaps even five, which was very discouraging. Nowadays, therefore, all captured starfishes are brought ashore and left there, and often are made use of by being ground up with oyster-shells, fish-bones, etc., into an excellent fertilizer.

What is that greenish-gray object covered all over with spikes? It is clinging in a little hollow of the rock, half hidden in seaweed of the same color.

Ah! that is a sea-urchin, and although it looks so very unlike them it is really a kind of first cousin to the starfishes. Here is a dead one from which the spines have been knocked off. Just look at it carefully, and you will see that it is very much like a starfish rolled up into a ball. See, you can trace the five rays quite easily, and if you look at it through a strong magnifying-glass you will find that its surface is pierced in hundreds of places with tiny holes through which it can poke out little sucker-feet, just as the starfishes do.

Look again at the shell from which the spines have been knocked away. Do you see that it is covered all over with little pimples? Now on every one of these pimples a spine was fastened by a kind of ball-and-socket joint, the pimple being the ball, and the socket lying inside the base of the spine; and by means of special muscles the animal could move the spines about, just as though it were a kind of hedgehog. In fact, this is the reason why it is called sea-urchin, for urchin is an old name for hedgehog. So, when a sea-urchin crawls about, it does so partly with its sucker-feet, and partly with its spines as well.

Sometimes, however, these creatures use their sucker-feet for quite a different purpose. They poke them out as far as they can from among their spines, and then take hold of little stones, small pieces of broken shell, and other bits of rubbish which they find at the bottom of the sea, and cling to them very tightly. The consequence is that you cannot see the animal at all, for it is quite concealed by this curious covering, and unless you were to take it out of the water, you would never have the least idea what it really was.

Now look at the mouth of this spiky sea-urchin. You will find it in the very middle of the lower part of the body. Do you see what great teeth it has? There are five of them arranged in a circle as in the mouth of a starfish, and they are made in just the same way as the front teeth of a rat or a rabbit, that is, they never stop growing all through the life of the animal, so that as fast as they are worn away from above they are pushed up from below, and thus always keep just the proper length and sharpness.

Sea-urchins are rather few and small along the shores of southern New England, but more numerous northward, and on rocky bottoms offshore. On the offshore bottom there lives also a queer sort whose shells are often cast up and are well known to the children as sand-dollars.

These are about the size and shape of one of mother's cookies, and are covered with a stiff brown fur of short spines. On one side--the under one--is the little mouth, and around it the faint outlines of five radiating arms, each sketched, as it were, by a double row of "pin-pricks" where the almost invisible feet are pushed out. These sand-dollars are creeping about at the bottom in myriads where the water is a few fathoms deep; and storms cast up thousands upon the beaches or into the tide-pools, where very likely we may find some in the course of our next visit to the ocean-side.

IV

BETWEEN TIDE-MARKS

We must start early on our walk today, as soon as the tide falls away from the piece of rocky shore we have in mind, so that we may have plenty of time; for the field which we have left until the last is the richest the seaside naturalist has to explore.

As the sea sinks away it uncovers not only the weedy ledges which we studied the other day, but also spaces between them of low rocks and loose stones half sunk in mud and sand. There is much to interest the botanist, too, but he will have to look out for himself. We have more than enough to do to look after the animals.

Many dead shells are lying about, showing the various species of shell-fish which inhabit this shore or the waters of the offing. Some of them we already know, and others we can never expect to get alive except by dredging. Such are the scallops, which rarely come up as far as low-water mark, in spite of their wandering habits; and the jingleshells or goldshells, although these, like the young oysters to which they are closely related, may usually be found clinging to stones, where they seem swollen scales or "blisters" of thin amber, or gold-colored horn. There is one--let us examine it. We can't pick it off, or even pry it off; but when we slip a knife-blade slowly beneath it, it comes loose, and we discover that this queer creature is a bivalve mollusk looking (and tasting) like an oyster, and with a small flat shell underneath the bulging top one. In this undershell is a large hole, through which passes a stout stony stalk which anchors this creature as firmly as an oyster is fixed by the cementing of its undershell to whatever it has attached itself when young.

The jingleshells are extremely numerous all along the coast south of Cape Cod, wherever the water is no more than about seventy feet deep, especially in Long Island Sound; and the oystermen gather them from the beaches and from their dredgings, and scatter their shells over the floor of the sound as "seats" for young oysters. They are especially useful for this purpose because they are so slight and brittle that when, as often happens, two or three minute oyster-larvæ settle down on one of these shells, they will, as they grow, break it apart by the strain, and then each oyster, relieved from the crowding of its mates, will form a round, nicely shaped shell instead of a narrow or misshapen one, and consequently be more valuable when it comes to be dredged up, after a couple of years or so, and offered for sale.

This rough space between tide-marks is a fine place for crabs. We have seen some of these creatures already, elsewhere; and our book (see