a pretty Sea Convolvulus, with its stems deeply buried. It is a cousin
of the common Bindweed. Then we see many plants of Thyme, and a few
ragged bushes of Gorse. We notice that several little plants grow near
the Gorse, as if they had crept there for shelter. The sea breeze has
blown the sand into heaps, and even on these dry, thirsty hillocks we
see many tufts of grass.
[Illustration: 1. THE COMMON LOBSTER. 2. HERMIT CRAB.]
These Couch Grasses and Dune Grasses, as they are often called, are
coarse and hard. Cattle pass them by in disgust. Yet they are the most
useful plants on the shore. They can live and spread where other plants
die. They have very long underground stems, which go through and through
the dry, loose sand. The wind does its best to bury them in sand, but
they send up hard, sharp buds, and go on living, and spreading.
Bit by bit, the sand is held together by the matted stems of these
grasses. It becomes firm, instead of loose; the wind can no longer blow
it about. Then other plants can grow in that place. You know how men go
out to the wild parts of the earth and, by hard work, make those places
ready for others to settle there. Well, the sand-grass works like that.
It prepares the way for useful plants to grow in places where they could
not grow before.
Quite near to the sea we shall find a very strange little plant. It has
no leaves, only fleshy, jointed stems. It is known as the Glass-wort,
being full of a substance useful in making glass. It belongs to a family
which seems to delight in deserts and salty soil! They have all sorts of
dodges to help them live in such places. For instance, their leaves are
fleshy. Squeeze them, and they are like wet, juicy fruit.
The Sea Beet is also a member of this family. The Red Beet, as well as
the Mangel-wurzel, we owe to this humble seaside plant. Most of our
sugar comes from the Sugar-beet.
Another useful plant is the Sea Cabbage, which grows on some parts of
our sea coast. It is rather a ragged, tough kind of Cabbage, and perhaps
you would not choose it for your dinner-table. We have more tempting
sorts in our gardens--Brussels Sprouts, Broccoli, Cauliflower, but long,
long ago the wild seaside cabbage was the only one growing. Men found it
to be eatable, and began to plant it near their huts or caves. From that
small beginning all our garden cabbages have come.
Walking a little farther from the sea, we leave the sand and come to
stones, rocks and cliffs. We pass a pretty plant, the Sea Lavender, and
another, the Sea Stock. They love best the sandy, muddy parts of the
shore. Their lilac flowers look bright and pretty. Coming to the rocky
places, we find tufts of the flower known as Sea Pink or Thrift. Its
leaves are like grass, and its flowers form a round pink bundle at the
top of a bare stalk.
There are many tufts of Thrift growing among the rocks; and each tuft
has a number of pink flowers. In some places you could step from one
tuft to another for several miles. Bare and ugly stretches of coast are
made into a gay garden by this lovely flower.
Here and there on the rocks is a plant with large yellow blossoms--the
Yellow Horned Poppy. It is a handsome plant, and you are surprised to
see such fine flowers among dry shingle, sand, or rock; but the Horned
Poppy is well able to stand the salt spray and storms of its favourite
home. When the petals have dropped, a green seed-pod is left. It is very
long--nearly twice as long as this page and looks much more like a stem
than a seed-pod.
Sometimes this seaside poppy is seen growing high up the face of the
cliff, where only the jackdaw and sea-birds can find a footing; and many
another plant may be seen there too. The cliffs are full of cracks, some
tiny and some wide. In these places there is always a certain amount of
dirt and grit. You could hardly call it "soil," and most plants would
starve if you planted them in such a place.
[Illustration: SEA LILY.]
These plants of the rock and cliff are not so proud. They have very long
and very thin roots, admirably suited to pierce the grit, and explore
the cracks in the rock, to find the moisture they need. Besides this,
they have fleshy leaves which help them to keep alive. The Stone-crop
and the Penny-wort are well-known plants of this kind. They grow where
you would least expect to find a living plant. Neither heat nor thirst
seems to kill them. Mother Nature has found many a wonderful way of
helping her children to live.
EXERCISES
1. Why do plants which grow in sand have such long roots?
2. In what way are the grasses growing on the sand so useful?
3. Give the names of four flowering plants of the shore.
4. Where would you look for the Stone-crop and Penny-wort?
5. Why do these two plants have such thin roots?
LESSON VII.
FLOWER-LIKE ANIMALS.
The prettiest of the creatures of the shore is the Sea Anemone. No one
can see it without being reminded of a flower, an Aster or Daisy, with a
thick stalk and many coloured petals; but, knowing how it is made, and
how it lives, we place it in the Animal Kingdom, though among the
lowliest members of that Kingdom. It is a cousin of that strange
creature, the Jelly-fish, which we shall look at in another lesson.
[Illustration: SEA ANEMONE.]
When the tide falls, you can walk among the rocks and pools by the sea,
and find Anemones in plenty. They are fixed to the rocks. Some are under
the ledges, out of sight, others are low down, half buried in the wet
sand; and others are on the sides of the rocks, looking like blobs of
green, brown, or red jelly. Feel one of them. It is slimy, and rather
firm, not so soft and yielding as the Jelly-fish. You cannot easily pull
it from the rocks without harming it; but you will find other Anemones
on stones and shells; and these you can put in a jar of sea-water, with
some weed, and carry home to examine later on.
When covered with sea-water the ugly blobs of jelly open out like
beautiful flowers. In some places along our coast the floor of the sea
is like a flower garden, gay with thousands of coloured Anemones.
Those little "petals" are really _tentacles_, used for catching and
holding food. We will use a shorter word and call them feelers. They are
set in circles round the top of the Anemone, and there are many of them.
The Daisy Anemone, for instance, has over seven hundred feelers. Each
feeler can be moved from side to side, and can also be tucked away, out
of sight and out of danger; but, when hungry, the animal spreads them
widely, for, as we shall see, they are the net in which it catches its
dinner.
The whole body of the Anemone is like two bags, one hanging inside the
other. The space between the two bags is filled with water. The feelers
are hollow tubes which open out of this space; so they, too, are filled
with water.
[Illustration: CRUSTACEA.
1. THE LARVA OF A LEAF-BODIED CRUSTACEAN CALLED PHYLLOSOMA.
2. A PRAWN-LIKE CREATURE, SHOWING THE FRONT LIMBS THAT ARE USED FOR
GRASPING PREY.
3. A CRAB.
4. THIS IS A SHRIMP-LIKE CREATURE CALLED CUMA SCORPIOIDES.]
The Anemone can press the water into them, and so force them to open
out. In rather the same way you can expand the fingers of a glove by
forcing your breath into them. The Anemone, you see, can open or close
just as it pleases.
What does it eat, and how does it find food? Perhaps you have watched an
open Anemone in a pool, or in a glass tank, and seen it at its meals. A
small creature swims near, and touches one of the feelers. Instead of
darting away, it appears to be held still; and then other feelers bend
towards it and hold the victim. Then they are all drawn to the centre of
the Anemone, carrying their prey with them; and the feelers, prey and
all, are tucked out of sight.
That is the way the Anemone obtains its food. As soon as the feelers get
hold of a small animal they carry it to the opening of a tube in the
centre. This is the mouth, leading to the stomach. Very often the
feelers, with their victim, are tucked away into the stomach, and the
feelers do not appear again for some time. Is not this a strange way of
eating!
Much stranger still is the way in which the food is held, and made so
helpless that it cannot escape. On the skin of the Anemone there are
many thousands of very tiny pockets, or cells. Each cell contains a fine
thread with a poisoned barb at the tip, The thread is packed away in the
cell, coiled up like the spring of a watch. As soon as anything presses
against the cells they shoot out their threads. Thus the tips of many
poisoned threads enter the skin of any soft animal which is unlucky
enough to touch an Anemone.
If your own skin is tender, these little stinging hairs will irritate
it, but not enough to hurt you. It is different, however, with the small
creatures of the sea. They are made quite helpless when caught by
hundreds of these strange threads. We shall find similar poison-threads
in the Jelly-fish; and these, in some cases, can cause us serious
illness. You cannot see them without the aid of a microscope.
All those parts of its food which the Anemone cannot digest, it throws
out again. If you feed an Anemone on raw meat, it tucks the pieces into
its mouth, and, some days after, throws out the hard part of the meat,
having taken all the "goodness" from it.
No doubt the Anemones themselves are eaten by other animals in the sea,
but many kinds of fish will not touch them. You may remember that we
noticed an Anemone which lived on the stolen home of the Hermit Crab.
The crab lives in the whelk shell, and the Anemone lives on the roof, as
it were. In nearly every ocean, all over the world, these two partners
are found, using the same shell. It is thought that the Anemone lives
there for two good reasons. First, the Hermit moves from place to place;
you can see that this would give the Anemone a better chance of
obtaining food. Also, bits of food float to the Anemone when the crab is
picking his dinner to pieces.
The crab seems to like having his strange partner with him. No doubt the
Anemone is of some use to him, or he would at once pull it off. It is
thought that the Anemone protects him from his enemies, the fish. Some
of them would swallow the whelk shell, crab and all, but they would not
eat one on which an Anemone was fixed. We are not _sure_ that these
reasons are the right ones. All we know for certain is, that a crab and
an Anemone have, for some good reasons, gone into partnership.
Anemones have large families. Sometimes they have numbers of eggs; at
other times their little ones come straight into the world as very tiny
Anemones. A boy who kept a large Anemone in a tank of sea water, was
astonished to find that in a short time, he had not one, but hundreds,
of the creatures. The tiny Anemones were fixed to the glass and rock,
all fishing for food with their little outspread tentacles. Sometimes
the Anemone will calmly divide itself into two, each half becoming a
perfect Anemone!
Anemones are of many shapes, sizes, and colours. The loveliest of our
British ones is the Plumose Anemone. It is like a carnation, and may
grow to be six inches high--that is, nearly as long as this page. It is
known by its shape, not by its colour. It may be any of these
colours--brown, deep green, pale orange, flesh colour, cream, bright
red, brick colour, lemon, or pure white.
There are many other creatures in the sea which resemble plants and are
often mistaken for them. The Sea Lily (p.49) is one of the flower-like
animals; it is a relative of the Starfish, living in deep water. The Sea
Mat (p.59) is often found on the shore. It seems like a horny kind of
weed, but is really a colony of tiny animals, each one having its own
little cell to live in.
EXERCISES
1. How does the Anemone expand its "feelers"?
2. In what way does the Anemone catch the small animals on which it
feeds?
3. Where is the mouth of the Anemone?
4. In what way might the Anemone be of use to its partner, the hermit
crab?
LESSON VIII.
SEA-WEEDS AND SEA-GRASS
We think of weeds as useless plants which insist on growing just where
they are not wanted. So it is a pity that _Sea-weeds_ are so named, for
the part they play in the sea is a useful one; and they are often
beautiful, though they do not bear flowers like so many plants of the
land. You see draggled heaps of them, lying on the shore where the waves
have thrown them. They are best seen in their proper home, buoyed up by
the water, and spreading out their broad coloured fronds, or long waving
threads. There are, in many places, meadows of Sea-grass, and forests of
Sea-weed! Mother Earth still has her carpet of green, even when covered
by the salt water. The plants are very unlike those of the land, but, as
you will see, they are of great use. We will suppose you put on a diving
dress. Then you can walk out, under the water, and explore the forests
of the sea.
Down by the line of low tide, before you have waded up to your knees,
you find plants clinging to the rocks. They cover them with a slippery
coat of green; when you turn these Sea-weeds over you find periwinkles
and other animals feeding or hiding. Sea-weed makes good "cover" for the
creatures of the rock-pools, who have many enemies to fear.
You notice that most of these shore weeds are green, sometimes as green
as young grass. Pull up a bunch of the weed, and you find that it clings
to the rocks and stones, but has no real roots. Seaweeds belong to a
humble family in the world of plants, having no real roots, no flowers,
and no real seeds. They can attach themselves to the stones or rocks.
Along comes a great wave, and perhaps they are torn up; but this does
not harm them, for they still live as they wash to and fro in the water,
until they cling to another rock. Or they are thrown on the shore to
die, or else to be washed back to sea by the next tide.
[Illustration: SEA-WEED FROND.]
The Sea Lettuce or Green Laver is a common seaweed near the shore. Its
broad, crinkled and bright green leaves are rather like those of a
lettuce. Sometimes it is boiled to a jelly and used for food. Many other
sea-weeds are good to eat, and on some coasts there is a regular
sea-weed harvest.
Now wade into rather deeper water, and you find a great mass of the
Bladder Wrack. Most schoolboys know it, for the little bladders of air
in the leaves explode with a pop if you squeeze them. The Bladder Wrack,
and others of the same kind, are torn up by the fierce waves in a storm,
and tossed on the beach in heaps. They are gathered by the farmer who
knows how to value a cheap manure for his fields. Some kinds are also of
use in packing lobsters so that they come to market nice and fresh.
When you have walked--in your diving dress--to deep water, you find
yourself among a tangle of olive-green weeds. They are below the line of
low tide. All round you is a forest of dark-green ribbons with wavy
edges. The ribbons are tough and very long, and cling tightly to the
rocks. These ribbon-weeds, and others of the same kind, are known as
Tangles. Round some parts of our coast they make wide, thick beds in the
sea. Though the ribbons may be six feet long, they are not so wide as
the palm of your hand.
Another sea plant, which grows in tufts in rather deep water, is called
Irish Moss; it is green, brown or purple in colour. I do not know why it
should be called Irish Moss, for it is not a moss, and it grows all
round the English, as well as the Irish, sea-coast. But sea-weeds have
strange names; indeed, many of them have no everyday names at all. Irish
Moss is used for food, after being boiled to a jelly. It can also be
made into a gum or glue, and has often been so used.
Now, if you were to walk still farther on the bed of the sea, into
deeper water, you would find the prettiest of all the sea plants. These
are the pink and red sea-weeds. You also find them on the beach, but
only after they have been torn from their home in the deep water. They
grow on the rocks, in pretty coloured tufts.
If you dive still farther, into the dark depths of the sea, you find
beds of ooze and slime, and rocks and weird fishes, but no plants. Why
is this? Like the land-plants, these sea-plants must have _light_. They
cannot grow in the blackness of very deep water. Can you guess why some
sea-weeds are green and others red? Those growing in the shallow water
of the shore are green, like land-plants, because the sunlight reaches
them. Only part of the light can pass through deep water; and so, in
these shady places, the sea-weed is reddish in colour.
[Illustration: SEA MAT.]
We see, then, that (1) green sea-weed grows by the shore; (2)
brownish-green sea-weed likes deeper water; (3) red sea-weed grows in
deep water; and (4) in very deep water there is no weed at all.
We must not forget the grass of the sea. It grows in narrow blades,
often a yard in length, and as wide as your thumb. It is not a sea-weed,
but a real flowering plant, which, for some reason or other, loves to
grow under water. It creeps in the sand and mud, with green leaves
growing up as thick as corn in a cornfield.
All these waving green leaves make large meadows in the sea; and
sea-snails, fishes, and crabs hide in it, just as all manner of living
things hide in the grass of our meadows. The proper name of this strange
plant is Sea Wrack. When dried, it is useful for packing up china, and
covering flasks of oil.
Now we come to the real use of sea plants. They are food for all the
hosts of small animals of the sea. These eat it as it grows; or else,
like the mussel and oyster, swallow the tiny scraps of it which float
everywhere like so much dust.
The shell-fish, and other animals which feed on sea plants, are
themselves eaten by other sea creatures, and these in their turn are
eaten by crabs, lobsters and fish, which are eaten by us. It reminds you
of a chain. The first link in the chain is the sea plant, the last links
are the fish and ourselves. So, you see, the weeds and grass of the
ocean are of very great value indeed.
EXERCISES
1. Give the names of three common Sea-weeds.
2. What is the colour of the weed found in deep water?
3. Why cannot Sea-weed grow in very deep water?
4. In what way are sea plants most useful?
LESSON IX.
THE JELLY-FISH.
Or all the queer children of Nature which live in the sea, the
Jelly-fish is one of the queerest. You often find it on the shore,
especially after a severe storm. There it lies, a mass of helpless
jelly, which slips and breaks through your fingers if you try to lift
it.
It cannot move back to its watery home, and in a short time the sun's
warmth will have dried it up, leaving but a mark on the sand, and a few
scraps of animal matter; for these strange creatures are little else but
water. A Jelly-fish, which weighed two pounds when alive, would leave
less than the tenth part of one ounce when dried!
There is a story of a farmer who, on seeing thousands and thousands of
Jelly-fish along the shore, thought he would make use of them. He
decided that they would serve as manure for his fields, and so save him
much money. He went home, and sent men with wagons to be loaded with the
Jelly-fish. This was done, and the Jelly-fish were spread over the soil.
On looking at his fields the next morning, the farmer was astonished to
find that every scrap of his new manure had vanished as if by magic!
[Illustration: WEST PAN SAND BUOY. ONE OF THE MANY BUOYS AT THE MOUTH OF
THE THAMES.]
In the sea the Jelly-fish looks like an umbrella of bluish-white jelly,
from which hang tassels and threads. Look over the side of a boat, or
from the pier, and you often see them drifting by, hundreds of them,
like so many ghosts.
Each one is moving along, with its edges partly opening and shutting. It
is plain that this waving motion causes the creatures to move through
the water. Also, they can rise to the surface, or fall to the depths,
and do not collide with one another. So the Jelly-fish is not at all
helpless.
At night Jelly-fishes sometimes look very beautiful. Each one shines in
the water, with a soft yet strong light, like fairy lamps afloat in the
sea.
They are of all sizes. Some you could put in a small wineglass, others
measure nearly two feet across. Evidently the Jelly-fish grows, and, in
order to live and grow, it must eat; but what does it eat, and how does
it obtain its food?
[Illustration: MEDUSA.]
Before noticing the wonderful way in which this animal finds its dinner,
let us look at its body. In any large Jelly-fish you can see marks which
run from the centre of the body, and another mark round the edge of the
"umbrella." These are really tubes. They all join with a hollow space
inside the body, which is the creature's stomach. The mouth-tube opens
under the body, as can be seen by turning the Jelly-fish on its back,
and moving the lobes of jelly aside. All the food goes up this
tube-mouth, and so into the stomach of the animal. The whole creature is
little more than so many cells of sea-water, the walls of the cells
being a very thin, transparent kind of skin.
Perhaps the strangest thing about it is the way in which it catches
prey. Jelly-fish feed on all kinds of tiny sea animals, such as baby
fish, and the young of crabs, shrimps, and prawns. These small creatures
form part of the usual dinner of many a hungry dweller in the sea, and
the Jelly-fish takes a share of them.
[Illustration: A MEDUSOID.]
From the edge of the "umbrella" there hangs a fringe of long, delicate
hairs, rather like spiders' threads. These are fishing lines, yet much
more deadly. They trail through the water, stretching far from the main
part of the Jelly-fish; and any small creature unlucky enough to touch
them is doomed.
Down each one of these threads there are minute cells, hundreds and
hundreds to every thread; and in each cell there is a dart, coiled up
like the spring of a watch. The tip of the dart is barbed like a
fishhook. Now the cells are so made that they fly open when touched. The
dart then leaps out and buries itself in the skin of the animal which
touched the thread. Not only that, but the darts are poisoned, and soon
kill the small creatures which they pierce.
You see now how this innocent-looking Jelly-fish gets its food. As it
swims along, the threads touch the tiny living things in the sea, the
darts pierce them and poison them. Of course these stinging darts are
very, very small, much too small for our eyes to see.
Sometimes there are numbers of large brownish Jelly-fish in the sea, or
washed up on the shore. If you are paddling or swimming, keep well away
from them. Their poison darts are able to pierce through thin skin, and
may cause you illness and great pain. Remember that the threads are very
long; after you have passed the main body of the animal, you may still
be in danger from the trailing threads.
We noticed these same poison darts when we were dealing with the
flower-like animals, the Anemones. Only, in that case, they were so
fine, so small, that they had no power to harm us, even though they
entered our skin. You may remember that we called the Anemone a cousin
of the Jelly-fish, for they both belong to the same lowly division of
the Animal Kingdom.
Animals have queer ways of getting a living. Who would expect to find
millions of poisoned darts in a Jelly-fish? Who would guess that these
weapons are coiled up, ready to spring out at their prey? Men have made
many weapons for killing, from the bow-and-arrow to the torpedo, but
none of them is more wonderful than the weapon of the Jelly-fish.
EXERCISES
1. Where is the mouth of the Jelly-fish placed?
2. How does the Jelly-fish move through the water?
3. What is the food of the Jelly-fish?
4. How does it obtain its food?
[Illustration: SHELLS.
1. A FRESHWATER TURRET SHELL.
2. EDIBLE MUSSEL.
3. CONE SHELL.
4. SWORD-BLADE RAZOR-SHELL.
5. EAR SHELL, OR ORMER.
6. A TOP SHELL.
7. SCALLOP.
8. SWAN MUSSEL.]
LESSON X.
SHELLS AND THEIR BUILDERS (1).
THE PERIWINKLE, WHELK AND LIMPET.
Most of the shells which you find scattered over the shore are empty.
The little animals which built them are gone; and their empty houses, of
wonderful shapes and colours, are all that you find. Let us look at the
builders of these pretty homes.
The shell-builders have soft, juicy bodies, and they are put in one big
division of the animal kingdom--the _mollusca_, which only means
_soft-bodied_. Some of these molluscs do not build shells. But most of
them build a shelly house for themselves; they do this to defend their
soft bodies from the attacks of a host of enemies. Some build two
shells--the Oyster and Mussel do, as you know. These are called
_bi-valves_; that is, two valves or shells; and others, like the Garden
Snail, the Limpet, and Periwinkle, have one shell only, and so are
called _uni-valves_.