| By Author | [ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z | Other Symbols ] |
| By Title | [ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z | Other Symbols ] |
| By Language |
|
Download this book: [ ASCII ] Look for this book on Amazon Tweet |
Title: The Sea-Shore: Shown to the Children
Author: Wood, Theodore
Language: English
As this book started as an ASCII text book there are no pictures available.
*** Start of this LibraryBlog Digital Book "The Sea-Shore: Shown to the Children" ***
THE “SHOWN TO THE CHILDREN” SERIES
1. BEASTS
With 48 Coloured Plates by PERCY J. BILLINGHURST. Letterpress by LENA
DALKEITH.
2. FLOWERS
With 48 Coloured Plates showing 150 flowers, by JANET HARVEY KELMAN.
Letterpress by C. E. SMITH.
3. BIRDS
With 48 Coloured Plates by M. K. C. SCOTT. Letterpress by J. A.
HENDERSON.
4. THE SEA-SHORE
With 48 Coloured Plates by JANET HARVEY KELMAN. Described by REV.
THEODORE WOOD.
THE “SHOWN TO THE CHILDREN” SERIES
EDITED BY LOUEY CHISHOLM
THE SEA-SHORE
[Illustration: PLATE I
1. and 2. THE GOBIES.]
The Sea-Shore
SHOWN TO THE CHILDREN
BY
JANET HARVEY KELMAN
DESCRIBED BY
REV. THEODORE WOOD
[Illustration]
FORTY-EIGHT COLOURED PICTURES
LONDON & EDINBURGH
T. C. & E. C. JACK
Printed by BALLANTYNE, HANSON & CO.
At the Ballantyne Press, Edinburgh
LIST OF SEA-SHORE WONDERS
CHAPTER I
FISHES
Plate
I. 1. and 2. The Gobies
II. 1. The Smooth Blenny
” 2. The Spotted Gunnell
III. 1. The Dragonet
” 2. The Pipe-Fish
IV. The Flounder
V. The Plaice
VI. 1. The Egg of the Skate
” 2. The Egg of the Dog-Fish
CHAPTER II
THE MOLLUSCS
Plate
VII. 1. and 2. The Cuttle
VIII. 1. and 2. The Whelk
IX. 1. The Dog Whelk
” 2. The Sting Winkle
” 3. The Periwinkle
” 4. The Dog Periwinkle
” 5. The Purpura
X. 1. The Sea Snail
” 2. The Wentletrap
XI. 1. The Common Limpet
” 2. The Key-Hole Limpet
” 3. The Smooth Limpet
” 4. The Cup and Saucer Limpet
XII. 1. The Painted Top
” 2. The Grey Top
” 3. The Cowry
” 4. The Chiton
CHAPTER III
BIVALVE MOLLUSCS
Plate
XIII. 1. The Oyster
” 2. The Saddle Oyster
” 3. The Cockle
XIV. 1. Inside of Mussel Shell
” 2. The Mussel
” 3. The Horse Mussel
XV. 1. The Variable Scallop
” 2. The Radiated Scallop
” 3. The Hunchback Scallop
XVI. 1. Inside of Sunset Shell
” 2. The Sunset Shell
” 3. The Gaper
XVII. 1. The Piddock
” 2. and 3. The Little Piddock
XVIII. 1. The Shipworm
” 2. Wood bored by Shipworm
XIX. 1. The Razor
” 2. Top of Razor from Front
” 3. The Sabre Razor
XX. The Pinna
CHAPTER IV
CRABS
How Crabs Grow
How Crabs See
How Crabs Hear and Smell
Plate
XXI. The Edible Crab
XXII. 1. The Shore or Green Crab
” 2. The Fiddler Crab
XXIII. 1. The Masked Crab
” 2. The Thornback Crab
XXIV. 1. The Long-Beaked Spider Crab
” 2. The Four-Horned Spider Crab
XXV. 1. The Pea Crab
” 2. and 2 A. Crab Caterpillars
” 3. and 3 A. Crab Chrysalids
XXVI. 1. The Hermit Crab in Whelk Shell
” 2. The Hermit Crab out of Shell
CHAPTER V
LOBSTERS AND THEIR KIN
Plate
XXVII. The Lobster
XXVIII. 1. The Prawn
” 2. The Æsop Prawn
” 3. The Shrimp
XXIX. 1. and 1 A. The Sandhopper
” 2. and 2 A. The Sand Screw
XXX. 1. Acorn Shells
” 2. Ship Barnacles
CHAPTER VI
THE SEA WORMS
Plate
XXXI. 1. The Sea Mouse
” 2. The Sabella
XXXII. 1. and 2. The Serpula
XXXIII. 1. The Terebella
” 2. The Lug Worm
XXXIV. 1. The Nemertes
” 2. The Nereis
CHAPTER VII
STARFISHES
Plate
Starfishes’ Legs
XXXV. 1. The Five-Finger Starfish
” 2. The Bird’s-Foot Starfish
XXXVI. The Sun Starfish
XXXVII. The Brittle Starfish
XXXVIII. 1. The Sea Urchin without Spines
” 2. The Sea Urchin with spines
CHAPTER VIII
SEA CUCUMBERS AND JELLYFISHES
Plate
XXXIX. 1. The Sea Cucumber
” 2. The Common Jellyfish
XL. 1. The Stinging Jellyfish
” 2. The Sea Acorn
CHAPTER IX
SEA ANEMONES
How Sea Anemones are formed
Plate
XLI. 1. The Smooth Anemone
” 2. The Daisy Anemone
XLII. 1. The Thick-Armed Anemone
” 2. The Snake-Locked Anemone
CHAPTER X
MADREPORES, CORALS, AND SPONGES
Plate
XLIII. 1. The Madrepore
” 2. The Sea Finger
XLIV. 1. The Tuft Coral
” 2. The Bread-Crumb Sponge
” 3. The Grantia Sponge
” 4. Foraminifera
CHAPTER XI
SEA-WEED
Plate
XLV. 1. The Bladder-Wrack
” 2. The Oar Weed
XLVI. 1. Coralline
” 2. Dulse
XLVII. 1. The Green Laver
” 2. The Purple Laver
XLVIII. 1. Carrageen Moss
” 2. The Sea Grass
” 3. The Grass Wrack
ABOUT THIS BOOK
This book is intended to help little boys and girls to use their eyes.
The world is full of beautiful sights and wonderful creatures; and
some of the most beautiful and wonderful of all are to be seen on the
sea-shore. So I have tried to tell boys and girls, who are fortunate
enough to visit the sea-side, what they ought to look for, and where
they ought to look for it. And I can assure them that if they will only
take the trouble to see what there is to be seen, they will find fresh
objects of interest as often as they go down upon the beach, and that a
sea-side holiday will prove ten times as delightful as ever they found
it before.
THEODORE WOOD.
THE SEA-SHORE
CHAPTER I
FISHES
PLATE I
THE GOBIES (1 and 2)
In this little book I want to talk to you about some of the strange
and wonderful creatures which you may find when you go to stay by the
sea-side. And first of all I should like to tell you something about
the fishes. A great many of these, of course, live in the deep water,
where you cannot catch them, or even see them. But there are a good
many others which you can find very easily indeed. All that you have to
do is to wait until the tide has gone out, and then to go down and look
into the pools which are left among the rocks. There you are almost
sure to see a number of shadowy forms darting to and fro through the
water. Some of these, most likely, will be shrimps and prawns, which
are always very common in the rock-pools; but the others will be tiny
fishes. And even if you have not got a net you can often catch them
quite easily. Just bale out the water with a small pail, or even with
your hands, until the pool is nearly empty, and you will be able to
seize them with your fingers.
Among the fishes which can be caught in this manner are several kinds
of Gobies. You can easily tell them from all other fishes by the
curious way in which their lower fins are made. These fins are placed
close together, so as to form a kind of cup-shaped sucker or soft pad,
by means of which the little creatures can cling so firmly to the rocks
that even a wave will not wash them from their hold. And if you take
them home alive and put them into a basin full of sea-water, they will
cling to the sides and stare at you in a most inquisitive way! Owing to
this habit the gobies are often called “rock-fishes.”
The commonest of these odd little creatures, perhaps, is the Black
Goby. But the Spotted Goby is very nearly as plentiful. It is rather
hard to see, because it is coloured just like the sand at the bottom
of the pool, on which it is very fond of resting. But if you scoop out
the water from a shallow pool you will often find, not only the goby,
but its nest as well. For this little fish makes a most curious nest in
which to place its eggs. First of all it hunts about till it has found
half an empty cockle-shell, lying at the bottom of the water with its
hollow side downwards. It then scoops out the sand from underneath it,
so as to form a little chamber about as big as a marble. You would
think that the walls of this chamber would very soon fall in, wouldn’t
you? But the fish smears them all over with a kind of slime, which very
soon sets and becomes quite hard, just like cement. It then makes a
tunnel leading into the chamber by means of which it can go in and out;
and last of all it covers the cockle-shell all over with loose sand.
So unless you look very carefully at the bottom of the pool you will
not see the nest at all. But if you notice a kind of lump in the sand,
and find that half a cockle-shell is buried underneath it, you may be
pretty well sure that you have discovered the home of a spotted goby.
This nest is always made by the male fish, and when it is quite
finished his mate comes and lays her eggs in it. Then for eight or nine
days he remains on guard outside the entrance, so as to prevent any
hungry creature from finding its way in and devouring them. At the end
of that time the eggs hatch, and a number of baby gobies make their
appearance; and although they are so small that one can hardly see
them, the father-fish seems to think that they are quite able to take
care of themselves. So he swims away, and leaves them to their fate.
If you catch these little fishes with your fingers you must be careful
how you handle them, for they have rather long and sharp teeth, and can
give quite a smart bite.
PLATE II
THE SMOOTH BLENNY (1)
This fish, which is sometimes known as the Shanny, is also very common
in the rock-pools. But you are not likely to see it unless you bale out
all the water from a pool, for it always hides during the daytime in
the crannies among the rocks, or underneath sea-weeds. Or it will even
burrow down into the sandy mud beneath a big stone, so that you will
not find it at all unless you dig for it.
When it is fully grown this fish is about five inches long, and it is
quite a remarkable creature in several different ways.
In the first place, it varies a great deal in colour. Sometimes it is
partly green and partly yellow, sometimes it is olive brown nearly all
over, and sometimes it is almost black. But you can always tell it by
the ring of bright crimson which surrounds each eye.
In the second place, it can remain for quite a long time out of the
water. Some fishes die almost at once if they are taken out of the sea.
But a blenny can live on dry land for twenty-four hours at least. The
reason is that its gills are made in such a way that they remain damp
for a long while after the fish leaves the water; and as long as the
gills are moist it is able to breathe.
[Illustration: PLATE II
1. THE SMOOTH BLENNY.
2. THE SPOTTED GUNNELL.]
So very often indeed a smooth blenny will hide in a crevice which is
left quite dry when the tide begins to fall, and will stay there till
it rises again, perhaps eight or ten hours later.
But the oddest thing about this little fish is that it can move one
of its eyes about without moving the other! Have you ever seen a
chameleon? If so, you must have noticed how it will turn one of its
curious eyes, first in one direction, and then in another, while the
other eye remains quite still. And the blenny can move its eyes in
just the same way, so that very often when one of them is looking out
in front the other will be looking out behind. And then one will twist
round and look upwards, while the other twists round and looks down!
If you succeed in catching a smooth blenny, you can always tell it from
the other fishes which live in the rock-pools by the deep notch in the
middle of the fin which runs along its back.
PLATE II
THE SPOTTED GUNNELL (2)
Another small fish which is very common in the rock-pools is the
Spotted Gunnell. It is often known as the “butter-fish,” and if you try
to catch it you will very quickly learn the reason why; for it will
slip between your fingers just as if it had been smeared all over with
butter. Nearly all fishes are slippery, but the spotted gunnell is the
most slippery of all, for its whole body is covered with such a thick
coat of greasy slime that it is really hardly possible to hold it.
Sometimes the spotted gunnell is light brown in colour, and sometimes
it is dark brown. But you can always tell it by its shape, which is
very much like that of an eel, for its body is long and flat, and is
of almost the same width the whole way along, from the head to nearly
the tip of the tail. Then instead of having two fins on its back quite
separate from one another, as most fishes have, the spotted gunnell has
one very narrow fin which runs the whole length of the body. So, you
see, it is very much like an eel indeed. But you can always tell it by
the row of black spots, bordered with white, on the lower edge of the
back-fin. When fully grown it is about six inches long.
PLATE III
THE DRAGONET (1)
You will not find this little fish in the rock-pools nearly so often
as the gobies and the gunnells, for it generally lives at the bottom
of the sea at some little distance from the shore. But now and then it
comes swimming up as the tide rises, and gets left behind as it falls
again, so that for a few hours, at any rate, it is obliged to stay in
the pools. It is a most beautiful little creature, and, strange to
say, the male is much more handsome than the female, for he is golden
yellow above and white beneath, with streaks and spots of lilac upon
his back and sides, while his mate is reddish-yellow all over. Besides
this, he has the front spine of his first back-fin drawn out to such
a length that it reaches almost to the tip of his tail, while all his
other fins are very long and very spiny. He really does look, indeed,
very much like a tiny water-dragon. That is the reason, of course, why
he is called the “dragonet.” The female, however, has much smaller
fins. Indeed, she is so very unlike the male that until a few years ago
even naturalists thought that she was a different fish altogether, and
she was generally known as the Fox, on account of her reddish colour.
[Illustration: PLATE III
1. THE DRAGONET.
2. THE PIPE-FISH.]
If you ever succeed in finding a dragonet in the rock-pools it is
almost sure to be a female, for the male hardly ever comes into shallow
water.
PLATE III
THE PIPE-FISH (2)
This is a very odd-looking fish indeed--quite the most curious of all
the fishes which live in the rock-pools. And as it is very common, you
ought to be able to find it without any difficulty.
In the first place, although it grows to a length of eighteen or
nineteen inches, its body, even in the largest part, is no bigger round
than a slate-pencil. For this reason it is often known as the Needle
Fish.
Besides this, its jaws are drawn out to a most wonderful length, and
are fastened together all the way along, so that they really form a
kind of tube. So, you see, a pipe-fish can never open or shut its
mouth, but has to suck in its food through the tiny hole at the tip of
the jaws.
Sometimes, as you look down into a rock-pool, you may see one of these
fishes feeding; and the way in which it does so is very curious indeed.
It suspends itself almost upright in the water, with its tail upwards
and its head downwards. It then fills its tube-like mouth with water,
which it squirts out again as hard as it possibly can. The result is,
of course, that the sand at the bottom of the pool is blown away, and
the various tiny creatures which were lying hidden underneath it are
uncovered. Then the fish sucks them up into its mouth, and swallows
them.
Another curious fact about the pipe-fish is that instead of being
clothed with scales, as most fishes are, it is covered all over with
hard bony plates, just like a suit of armour. But the strangest thing
of all about it is that underneath the body of the male fish is a kind
of pouch, into which the female puts her eggs, so that he can carry
them about in safety until they hatch! Isn’t that odd? And it is even
said that after the little fishes are hatched they will go back into
their father’s pouch if they are frightened, just as baby kangaroos do
into that of their mother, and remain there until the danger has passed
away!
PLATE IV
THE FLOUNDER
This is one of the “flat fishes,” as everybody calls them, like the
turbot and the sole. Yet, really and truly, these creatures are not
flat at all. They are thin. For what we always call the back of a sole
is not really its back. It is one of its sides. And what we always call
its lower surface is not its lower surface, but its other side!
This sounds very strange, doesn’t it? But the fact is that when these
so-called “flat” fishes are first hatched they swim upright, just as
all other fishes do. Then their backs are upwards, of course, and their
lower surfaces are downwards, and one of their sides is on either side.
For about a month they swim about in this way. At the end of that time
a strong desire comes over them to go and lie down on the sand or mud
at the bottom of the sea. Now, in order to do this, of course, they
have to lie upon their sides. Then three very strange things happen.
In the first place, their colour changes. Until now, both sides of the
body have been pearly or silvery white. A white fish, however, lying on
yellow sand or brown mud, would be very easily seen, and some hungry
creature would be sure to catch sight of it and devour it. So as soon
as the little fish lies down the upper side begins to get darker, and
in a very short time it is of just the same colour as the sand or mud
all round it. If you look into a shallow pool in which some of these
fishes are lying you will find it very difficult indeed to see them,
for they look exactly like the surface on which they rest.
In the second place, their way of swimming changes. When they first
hatch out from the egg these little fishes swim just as other fishes
do--upright, by means of their tails. For of course you know that
fishes do not swim with their fins, which merely help them to keep
their balance in the water. But when they lie down at the bottom of the
sea they give up this way of swimming, and wriggle their way, as it
were, through the water, still lying upon one side.
[Illustration: PLATE IV
THE FLOUNDER.]
But the oddest change of all takes place in the position of the eyes.
You can easily see, of course, that if a fish with its eyes in the
usual place lies down on one side at the bottom of the sea, one eye is
underneath its head, and is quite useless. So you might think that,
except when it was swimming, it would only be able to see with one
of its eyes. But a very strange thing indeed happens as soon as it lies
down on the mud. The lower eye actually begins to move, and slowly
travels round the head, till at last it settles down by the side of
the other! That sounds impossible, doesn’t it? It is as wonderful as
anything in a fairy story. Yet in every one of these so-called “flat”
fishes that strange journey of the eye takes place.
Next time you pass by a fishmonger’s shop just look at the soles or the
flounders in his window, and you will see that in every one of these
fishes the two eyes are quite close together, above the same corner of
the mouth. That is because one of the eyes moved right across the head
while the fish was quite small, so that it might be able to use them
both as it lay at the bottom of the sea.
You can sometimes catch flounders by paddling in the sea in places
where the bottom is rather muddy. After a little while you are almost
sure to feel one of these fishes wriggling underneath your feet, and
all that you have to do is to stoop down and seize it.
PLATE V
THE PLAICE
In its habits the plaice is very much like the flounder, except that
it does not like lying upon mud, and always chooses a spot where the
bottom of the sea is sandy. And the skin of the upper side of its
body, instead of growing dark brown, like the colour of mud, becomes
speckled and spotted like the surface of sand. The fish is always very
careful indeed to conceal itself, for even when the sea-bottom is sandy
it does not lie upon the surface, but wriggles its way right down into
the sand, only leaving just its eyes and a small part of its head above
it.
You can always tell a plaice when you see it by the bright
reddish-yellow spots upon the upper side of its body and its fins. And
besides these, it always has a row of little bony knobs on the upper
side of its head. You can catch it just as you can catch flounders, by
paddling in the sea. But the plaice which are caught in this way are
always quite small ones, for the bigger fish, which sometimes weigh as
much as twelve or even fifteen pounds, live in the deeper water at some
little distance from the shore.
PLATE VI
THE EGG OF THE SKATE (1)
Very often indeed, as you walk along the sea-shore, you will find a
curious object which the fishermen generally call a “mermaid’s purse.”
It is about three inches long and two inches wide, and is made of a
black, horny substance, so tough and hard that it is very difficult
indeed to tear it. And from each corner there projects a slender tube,
about an inch in length. In fact it looks rather like a hand-barrow,
with handles in front as well as at the back, instead of wheels.
[Illustration: PLATE V
THE PLAICE.]
This is an egg of that very curious fish which we call the Skate,
and which looks something like one of the “flat” fishes with a long
whip-like tail. So it is sometimes called a “skate-barrow.” When it is
flung up on the beach by the waves the egg is nearly always empty. But
if you happen to be staying by the sea-side in the early spring, and go
down for a walk along the beach after a violent storm, you may perhaps
find one of these eggs with a baby skate inside it. And if you examine
the egg very carefully, you will find that while one end is firmly
closed up, the other end has a slit running right across it, and that
this slit is made in such a way that it allows the little fish to pass
out quite easily when the proper time comes, but quite prevents any
other creature from coming in.
PLATE VI
THE EGG OF THE DOG-FISH (2)
On some parts of the coast you may often find an empty egg which is
very much like that of the skate, for it is made of just the same horny
material, and is of just the same shape. But at the four corners,
instead of having straight projections like the handles of a barrow, it
has long, twisted tendrils, just like those of a vine.
This is the egg of the Dog-fish, which is really a kind of small shark.
It is not big or strong enough to be dangerous to human beings; but it
is a terrible enemy to such small fishes as pilchards and herrings. For
a number of these creatures form themselves into a band and go hunting
together, just like a pack of wild dogs. And they will follow the shoal
about day after day, snapping up the poor helpless fishes in hundreds
and thousands.
When a dog-fish lays its eggs, it seems to fasten them down by their
tendrils to the weeds which are growing at the bottom of the sea; and
these hold them so firmly that unless the weeds are torn up with them,
they never break away. At each end of the egg is a small hole, allowing
a current of water to pass over the little fish inside it. And at one
end there is a slit, just like that in the egg of the skate, which can
only be pushed open from the inside. So the little dog-fish can get
out, while its enemies cannot get in.
[Illustration: PLATE VI
1. THE EGG OF SKATE.
2. THE EGG OF DOG-FISH.]
Very often, after a violent storm, you may find a dead dog-fish lying
upon the shore; and even if you have never seen one of these creatures
before you can tell at once what it is, because its skin is so rough
that it feels exactly like a piece of sand-paper. So this skin is
often used for covering the handles of swords, in order to give a firm
grip; and sometimes narrow strips of it are fastened to the sides of
boxes of lucifer matches.
CHAPTER II
THE MOLLUSCS
PLATE VII
THE CUTTLE (1 and 2)
We now come to the Molluscs, or Soft-bodied Animals, of which there are
a very great many. Some of them live in shells, like the oyster and
the whelk, and are often spoken of as “shell-fishes.” But they are not
really fishes at all, for they have no bones as fishes have, and are
made in quite a different way. And there are just a few of them which
have no shells at all.
One of these is that very curious creature which we call the Cuttle.
You may sometimes find it in the rock-pools, lurking in the crevices
among the rocks, or hiding under the masses of sea-weeds which grow
round the edges. It has a soft, white, bag-like body, and a big head,
on which are two great staring black eyes. Just above these eyes eight
long slender arms spring out; for cuttles keep their arms on their
heads instead of on their bodies! And another arm which is even longer
still, and is flattened out at the end into a kind of oval plate, hangs
down on either side.
All these arms are set with rows of round suckers, which are so
strong that if even a small cuttle catches hold of you, it will not
be very easy to make him let go. So if you do happen to find a cuttle
in a rock-pool it will be better to watch him in the water, without
attempting to catch him.
Down in the middle of all these branching arms, just where they spring
from the head, are two very curious organs. The first of these is the
beak, which is very strong, very sharp, and a good deal hooked. In
fact, it is rather like that of a parrot. The other consists of two
tubes which run downwards into the head, lying side by side together
like the barrels of a double-barrelled gun.
These tubes are called the “siphon,” and they are used for three
purposes.
First of all, they are used for breathing. The cuttle breathes water by
means of gills, like those of fishes, which lie inside the head; and
the water passes down to them through one of the siphon tubes, and then
goes out again through the other.
Next, they are used for swimming. When a cuttle wants to swim it
gathers all its arms together in front of its head, fills both its
siphon tubes with water, and then squirts their contents out again as
hard as it can. The result is that two jets of water come rushing out
of its head with such force that the surrounding water cannot give way
fast enough before them. So they push the cuttle backwards so swiftly
that if it were to dart across the pool you would hardly be able to
follow its movements.
The third use of the siphon tubes is a very strange one indeed.
Sometimes while you are looking at a cuttle in a rock-pool, the water
all round it will suddenly become quite dark, just as if a quantity of
ink had been poured into the pool. And so it has; for inside its body
the cuttle has a bag which contains a quantity of a deep black liquid
called “sepia.” This bag is surrounded by powerful muscles, and opens
into the siphon tubes; so that when the animal contracts the muscles,
the sepia is squirted out into the pool. It always does this if it is
frightened; and under cover of the darkened water it nearly always
succeeds in making its escape.
Inside its body the cuttle also has a very curious object which is
generally called a “cuttle-bone.” It is not really a bone, however, but
is made of almost pure chalk, and seems to act as a kind of support for
the bodily organs.
[Illustration: PLATE VII
1. THE CUTTLE.
2. THE EGGS OF CUTTLE.]
Another very odd thing about the cuttle is the way in which it lays its
eggs. These look just like purple grapes, and each has a small stalk,
by means of which they are fastened together in bunches. Indeed, the
fishermen always call them “sea-grapes.” You may often find them lying
about upon the beach in early spring, and if you open one of them
carefully, you will find a little baby cuttle inside it.
PLATE VIII
THE WHELK (1 and 2)
Everybody knows the shells of whelks by sight, and you can hardly take
a walk along the sea-shore without seeing hundreds of them lying about
on the beach. And great numbers of whelks are caught for human food,
and also to serve as bait for fishes.
One very curious thing about whelks is the way in which they lay their
eggs. Very often indeed, as you walk along the sandy sea-shore, you
will notice round clusters of yellowish white eggs, which often go
rolling along before the wind. Each of these clusters is about as big
as a cricket-ball, and the eggs of which it is made up are about as
large as peas. Now these are the eggs of whelks, and I think that every
one who sees them must wonder how these creatures can possibly manage
to lay such very big balls of eggs. For each egg-ball is at least two
or three times as big as the biggest whelk.
But, after all, the explanation is quite a simple one. When the eggs
are first laid they are very small indeed. Each is no bigger than a
tiny pin’s head. Instead of having shells, however, these eggs have
tough but very elastic skins; and these skins are made in such a way
that while they allow water to soak in from the outside, they will not
allow it to pass out again. So as soon as the eggs are dropped into the
sea they begin to swell; and the result is that before very long each
egg is as big as a good-sized pea.
If you pick up a cluster of these curious eggs in the early spring and
open them, you will find inside each the shell of a very tiny whelk,
which is almost ready to hatch out.
PLATE IX
THE DOG WHELK (1)
If you look in the ridges of small pebbles and bits of broken coal
which you will meet with here and there on the sandy parts of the
sea-shore, you are quite sure to find a number of very small whelk
shells. They are brownish yellow outside, and pinkish white inside, and
instead of being quite smooth, like those of the common whelk, they
are covered with a number of ribs which run down from the peak to the
margin. And these ribs are broken up in such a way that they look
almost like rows of beads.
[Illustration: PLATE VIII
1. THE WHELK.
2. THE EGGS OF WHELK.]
These are the shells of the Dog Whelk, and if you wait until the tide
is quite low, and then hunt about on the weed-covered rocks close to
the edge of the sea, you will very likely find some of the living
animals crawling about. They feed upon the sea-weeds by means of a
curious organ called the tooth-ribbon. This is just a narrow strip
of gristle, set with row upon row of very tiny hooked teeth; and by
drawing this backwards and forwards over the leaves of the weeds the
animal scrapes off very tiny pieces, which it then swallows.
In the tooth-ribbon of one of these whelks there are about a hundred
rows of teeth, with about nine teeth in each row: so that the animal
has nearly a thousand teeth altogether. But of course you can only see
them by means of a powerful microscope.
PLATE IX
THE STING WINKLE (2)
Although this creature is called a “winkle” it is really one of the
whelks. It is very common, and you may often find its empty shell lying
upon the shore. It is white, or yellowish white, in colour, and is
generally about an inch and a half in length, with several high ridges
running down it from the top to the bottom, and a number of smaller
ridges running crosswise between them.
You would not think that this could be a very dangerous creature, would
you? It looks as harmless as it can possibly be, and certainly you
need not be in the least afraid to pick up a sting winkle if you find
one crawling about, for it cannot injure human beings. But to other
shell-bearing molluscs it is a very terrible foe indeed. I dare say
that you have often noticed, when you have been picking up shells on
the sea-shore, that a good many of those shells had small round holes
bored through them. Well, those holes were pierced by a sting winkle.
For this animal is a creature of prey, and feeds entirely on other
animals which live in shells; and when it meets with one it fastens
itself to its victim’s shell, and drills a hole right through it by
means of its tooth-ribbon. It then pokes the tooth-ribbon through the
hole into the body of the animal inside, and draws it back again. As
it does so, of course, the sharp hooked teeth drag away little bits of
the animal’s flesh, which the sting winkle swallows. It then pokes its
tooth-ribbon down again into the body of the victim, and so on, over
and over again, until its hunger is satisfied.
PLATE IX
THE PERIWINKLE (3 and 4)
Of course you know the Periwinkle very well indeed by sight--and
very likely by taste, too! So there is no need for me to describe
it. But perhaps you did not know that there are two different kinds
of periwinkles. One of these is the Common Periwinkle, which is very
plentiful indeed on many parts of the coast. You may find it in
thousands and thousands if you hunt about on the weed-covered rocks
near the water’s edge when the tide is out, and no matter how many of
them are caught, there always seem to be just as many again next day.
This is the periwinkle which is used for food.
The other is the Dog Periwinkle. It is rather larger, and has a stouter
shell. If you want to find it, you must look on the rocks about
half-way between high and low water-marks, and there you will generally
find it crawling about in numbers. But it is not good for food, because
it often has a quantity of eggs inside its body, and inside these eggs
the shells of the baby periwinkles are already formed, which make it
dreadfully gritty. Thrushes, however, as well as a good many of the
shore birds, do not mind this in the least, and they devour so many of
both these kinds of periwinkles that it is quite a wonder that any are
left alive.
PLATE IX
THE PURPURA (5)
In size and shape this very common creature is rather like the dog
periwinkle. But its shell is white in colour instead of bluish black,
and generally has two or three bands of light yellowish brown running
round it. You may often find it crawling about on the weed-covered
rocks when the tide is out.
[Illustration: PLATE IX
1. THE DOG WHELK.
2. THE STING WINKLE.
3. THE PERIWINKLE.
4. THE DOG PERIWINKLE.
5. THE PURPURA.]
The purpura is quite a famous creature, because of the use which was
made of it by the ancient Romans. I dare say you know that in days of
old the colour of purple was very highly valued; and among the Romans
only members of the royal family were allowed to dress in purple
garments. Now this purple dye was obtained from the purpura. Inside its
body this creature has a little bag which contains about a drop of a
thick white liquid, rather like milk. Certainly it does not look in the
least like purple dye. But if you were to squeeze it out on to a sheet
of white paper, and to place it in the sunshine, you would very soon
see that it was changing colour. In a few minutes’ time it would
have turned to yellow. After a little time longer you would notice a
blue tinge creeping into the yellow, and turning it to green; and by
degrees the blue would become stronger and stronger, till the green
disappeared. At last a crimson tinge would creep into the blue and turn
it to purple; and this would be exactly the same as the famous purple
dye which the ancient Romans valued so highly.
The eggs which are laid by the purpura are very curious indeed, for
they are fastened down to stones by little stalks; so that each one
looks rather like an egg-cup with an egg inside it. And inside each of
these eggs are several little purpuras instead of only one.
PLATE X
THE SEA SNAIL (1)
This is one of the very commonest of all the shell-bearing molluscs.
You may find it crawling about in numbers all over the weed-covered
rocks which are left bare as the tide goes down. Its shell varies
very much in colour, for it is sometimes bright yellow, and sometimes
pale yellow, and sometimes olive green, and sometimes brown, and
sometimes almost black. Indeed, you might almost think that there were
half-a-dozen different kinds of these sea snails instead of only one.
These creatures have tooth-ribbons set with hundreds of tiny hooked
teeth, just like those of the dog whelks, and they use them in feeding
upon the leaves of sea-weeds in just the same way.
PLATE X
THE WENTLETRAP (2)
The Wentletrap is one of the most beautiful of all the shells which are
to be found upon the shore. Indeed, I really think that it is quite the
most beautiful. For the high ridges which stand out so boldly run round
and round it in the most graceful curves, and the whole shell looks
just as if it had been carved out of ivory.
[Illustration: PLATE X
1. THE SEA SNAIL.
2. THE WENTLETRAP.]
The wentletrap is sometimes known as the “staircase shell,” because the
ridges which run round it are very much like those spiral staircases
by which one climbs to the tops of church towers and other lofty
buildings. If you want to find it, the best place to look is in the
ridges of small pebbles which are washed up here and there on sandy
coasts by the waves, and which are generally mixed up with broken coal
which has been thrown out from passing ships. But it is not very
common, and you must not be disappointed if you do not succeed in
finding it.
PLATE XI
THE COMMON LIMPET (1)
This is a very common creature indeed, and you can find it in hundreds
and thousands on any rocky part of the coast. Numbers of its empty
shells are to be found lying about on the beach, and if you go down
among the rocks when the tide is out you will often notice that in some
places they are so covered with limpets that you can scarcely put the
tip of your finger in between them.
These animals cling to the rocks in the most wonderful way. Indeed,
if you take hold of a big limpet between your fingers you will not be
able to move it in the least, even if you pull at it and push at it as
hard as you can. But if you take the animal by surprise, and give it a
sharp, sudden blow sideways with a stone, or the end of a stout stick,
you can generally knock it off quite easily. And you will very often
find that a deep ring-shaped mark has been worn away in the rock by the
sharp edges of its shell.
However, limpets do not always remain clinging to the rocks, for they
can crawl about quite as easily as snails can, by means of that soft,
fleshy part of the body which we call the “foot.” And if you take them
home alive, and put them into an aquarium, you may often see them
creeping up and down the glass sides, through which you can examine
their bodies quite easily.
PLATE XI
THE KEY-HOLE LIMPET (2)
There are a good many different kinds of limpets, of which one of the
most curious is the Key-hole Limpet. It is generally found in rather
deep water, but you may sometimes find it clinging to the rocks just
above low-water mark. You must choose a season of “spring-tide,”
however, for then the tide goes farther out than usual, and leaves
behind it a good many creatures which at other times one hardly ever
sees.
The shell of this creature is rather stouter than that of the common
limpet, and has a number of ridges running down it from the peak to
the margin. Even by these you can tell it at once. But if you look at
it closely, you will also find that just at the top of the peak there
is a hole shaped rather like a key-hole. Through this hole the animal
squirts out the water which has passed over its gills; so that all the
time that it is breathing, if only one could see it, a kind of little
fountain is playing under water, spouting out from the top of its shell!
PLATE XI
THE SMOOTH LIMPET (3)
At first sight, perhaps, you would hardly take this creature for a
limpet at all, for it is ever so much smaller than either the common or
the key-hole limpets, and has a very thin and delicate shell indeed. It
varies a good deal in colour, but generally the shell is pale brown,
looking almost like polished horn, with eight or nine narrow streaks
of bright blue running down from the peak to the margin. It is often
called the “bonnet shell,” because in shape it is rather like an
old-fashioned bonnet.
You may often find the empty shells of this creature lying upon the
shore. But if you take them home you will find that as soon as they
become dry the beautiful blue streaks begin to fade, and that after a
few days you can hardly see them at all.
PLATE XI
THE CUP AND SAUCER LIMPET (4)
This is a very curious creature indeed. But if you want to see why its
rather odd name was given to it, you must look inside its shell instead
of outside. Then you will see that in the upper part is a curved plate
which really looks very much like a tiny tea-cup, while the shell
itself surrounds it just like a saucer. And if you were to examine the
animal which lives inside it very carefully, and to pull out its long
tooth-ribbon, you would find at the tip of it a curious little organ
which looks just like a tea-spoon. So that we have cup, saucer, and
spoon all in one!
Perhaps you may wonder what the odd little cup is for. Well, the fact
is that the muscles by means of which the animal clings to the rock are
very strong indeed. So, of course, there must be something else very
strong to which they can be fastened, and this cup-shaped plate gives
them a very firm hold.
The cup and saucer limpet is not a very common creature, and in many
parts of the coast it is never met with at all. But if you stay by the
sea-side on the south coast of England, you may sometimes find its
empty shell lying upon the shore.
[Illustration: PLATE XI
1. THE LIMPET.
2. THE KEY-HOLE LIMPET.
3. THE SMOOTH LIMPET.
4. THE CUP AND SAUCER LIMPET.]
PLATE XII
THE PAINTED TOP (1)
Tops are generally very common indeed on the sandy parts of the shore.
You cannot possibly mistake their shells for those of any other
creatures, for they are cone-shaped, looking very much like rather
flattened sugar-loaves, and are generally very beautifully coloured. So
pretty are they, indeed, that they are sometimes strung together and
worn as necklaces, or used for ornamenting ladies’ dresses.
The painted top is one of the most beautiful of all these shells, for
it is covered all over with spots and streaks and blotches of scarlet,
and crimson, and pink, and purple, and white, and blue, and yellow! But
all this lovely colouring is only on the outer coat of the shell, which
is very easily chipped off. The consequence is that these shells are
very often damaged by being tossed to and fro by the waves, and though
you may often find twenty or thirty in the course of a morning, not
more than two or three, perhaps, will be quite uninjured.
Tops are very useful creatures to have alive in an aquarium, for they
keep the glass sides clean from the tiny green weeds which so quickly
grow upon them. They do this by means of their tooth-ribbons, and you
may see them crawling about on the glass walls and mowing down the
weeds, just as a gardener cuts the grass on the lawn with his scythe.
PLATE XII
THE GREY TOP (2)
The painted top is rather a large shell, for it is often nearly an inch
in height from the peak to the margin. But the Grey Top, which is even
commoner still, is a good deal smaller. It is not nearly so brightly
tinted as the painted top, for it is yellowish grey in colour, with
zigzag black streaks running round and round it, which give it rather a
mottled look. Still, it is a very pretty shell indeed.
If you look at a top shell from underneath, you will always find that
there is a small hole in the bottom. This is the entrance to a passage
which runs right up into the peak of the shell. In the grey top this
hole is just about big enough to admit a rather fine needle.
PLATE XII
THE COWRY (3)
No doubt you have often found this very pretty shell, for on the sandy
parts of our coasts it is sometimes very common. You may often find
twenty or thirty cowries, indeed, in one of those ridges of pebbles and
small coal which are washed up by every tide. But if you were to see
the living animals crawling about I do not think that you would ever
guess what they were, for their soft bodies come outside their shells,
which they cover up so completely that you can hardly see them at all.
If you look on the upper part of the shell, you will see that a pale
streak runs across it from one side to the other. This streak marks the
line where the edges of the two sides of the body almost meet.
In some parts of the world cowry shells are used instead of money. It
seems rather an easy way of getting rich, doesn’t it, just to go and
pick up shells on the sea-shore? But then fifteen hundred of these
cowries are only worth about a shilling, so that you would have to pick
up a very great many even if you only wanted to do a day’s shopping!
And then they are ever so much bigger than our English cowries, so
that it would not be very easy to carry them about. You would have to
take several sacks full of cowries with you when you went to make a
purchase, instead of just keeping your money in a purse!
PLATE XII
THE CHITON (4)
The chiton is one of the oddest of all the shell-bearing molluscs;
for it does not look like a mollusc at all. It looks much more like a
kind of sea woodlouse, or a very tiny armadillo. For instead of having
a single shell like a whelk or a periwinkle, or a double one like a
cockle or an oyster, it has eight shelly plates on its back which
overlap one another, just like the tiles on the roof of a house. And if
you touch it, it will often roll itself up into a kind of ball, just
like the pill-millepedes, or “monkey-peas,” which are so common in our
gardens.
[Illustration: PLATE XII
1. THE PAINTED TOP.
2. THE GREY TOP.
3. THE COWRY.
4. THE CHITON.]
This creature is called the Chiton, and if you want to find it you
must go and look on the piles at the end of a pier, or on the rocks
which are left bare at very low tides. There you will often find it in
hundreds. Generally it is ashy grey in colour, but it varies a good
deal in hue, and you will sometimes find examples which are streaked
and mottled with pink, and orange, and white, and lilac, and chocolate
brown.
Before a chiton reaches its perfect form it passes through a kind of
caterpillar stage, and then turns into a sort of chrysalis, just as an
insect does. And both the caterpillar and the chrysalis, strange to
say, have eyes upon their heads, while the perfect chiton has none. But
some chitons have eyes all over their shells instead, and in some of
these very odd creatures between eleven and twelve thousand eyes have
been counted, the shells being almost entirely covered with them; so
that the animals may really be said to see with their whole bodies!
CHAPTER III
BIVALVE MOLLUSCS
PLATE XIII
THE OYSTER (1)
The “bivalve” molluscs are so called because they live in shells made
of two parts, or “valves,” which are fastened together by means of a
hinge. There are a great many of these, and the Oyster is one of the
best known of them all.
This creature is only found in places where the bottom of the sea is
muddy, because in sandy places the sand is very apt to get into the
hinges of the shells and to prevent them from being closed; and in
that case the animal very soon dies from suffocation. So oysters are
generally found in the mouths of rivers, or in land-locked bays where
there is no sand at all.
The history of these creatures is a very curious one indeed.
In the month of May the mother oyster produces a very large number of
eggs--sometimes as many as eight or nine hundred thousand! These are
called “oyster spat,” and for several weeks she keeps them in her
gills. Then one day she suddenly opens her valves and squirts them
out into the water, where they look like a little cloud of the finest
possible dust. For a short time after these eggs hatch the baby oysters
swim about, and travel backwards and forwards as the tide rises and
falls. After a while, however, they sink down and fasten themselves to
some object at the bottom of the sea; and when once they have done this
they never move again. They always lie upon their left sides, with the
smaller and flatter of the two valves uppermost; and there they remain
for five years at least before they reach their full size.
Oysters feed, too, in a very odd way. You know, perhaps, that inside
the shell of an oyster there is a tufted organ which we call the
“beard.” This consists of the gills. Hidden away underneath these is
the mouth; and the gills do not merely suck out the air which has been
dissolved in the water, as those of other animals do, but sift out
every little tiny scrap of decaying matter which the oyster can use for
food as well. So an oyster’s gills enable it to breathe and to catch
its dinner at the same time!
PLATE XIII
THE SADDLE OYSTER (2)
This is a very curious oyster; for in its flat lower valve, just below
the hinge, is a large oval hole. Through this hole passes a strong band
of muscle, to which is fastened a kind of shelly knob which looks just
like a button. By means of this the animal fastens itself down to some
object at the bottom of the sea; and very often indeed it is found
attached to the shells of other molluscs, looking something like the
saddle on the back of a horse. That is why it is called the “saddle
oyster.”
Another curious fact about this creature is that very often its shape
completely alters as it grows older. While it is quite small it looks
very much like an ordinary oyster. But as time goes on it generally
takes the form of the object on which it rests. So you might easily
find half-a-dozen shells of the saddle oyster, not one of which would
be shaped like any of the others.
[Illustration: PLATE XIII
1. THE OYSTER.
2. THE SADDLE OYSTER.
3. THE COCKLE.]
PLATE XIII
THE COCKLE (3)
This is one of the very commonest of all the creatures of the
sea-shore, and you may find its heart-shaped shells lying about on the
beach in hundreds and thousands. In many places, indeed, cockle-shells
are found in such wonderful numbers that they are crushed up and used
for covering pathways instead of gravel.
Yet you may wander about on the shore day after day for weeks together
and never see a living cockle. How is this?
Well, the reason is that cockles live buried underneath the sand. If
you go down near the edge of the waves when the tide is quite low, and
just stand still for a minute or two and watch, you are almost sure to
see first one little jet of water, and then another, and then another,
come squirting up out of the sand into the air. Now these little jets
of water are thrown up by cockles which are lying buried in the wet
sandy mud below. For every now and then these creatures draw down a
little water into their gills, through one of their siphon tubes, and
when they have sucked all the air out of it they squirt it up again
through the other.
Would you like to dig one of them up and look at it? Well, just take
a wooden spade and try. You will find that you cannot do it, for the
cockle can dig a good deal faster than you can. The fact is that he has
a very strong, fleshy organ which we call the “foot,” and with this he
can burrow down into the sandy mud so quickly that by the time you have
dug to a depth of six inches, he will have gone down to the depth of
ten or twelve.
The cockle uses this “foot” for another purpose as well, for he can
jump with it. And if you did succeed in digging him out of the ground,
you would very likely see him skipping about in the most active way,
almost like a sandhopper!
Upon some parts of the coast another kind of cockle is found, which
has its “foot” of a bright red colour. For this reason it is generally
known as the “red-nosed cockle.”
PLATE XIV
THE MUSSEL (1 and 2)
Mussels are almost, if not quite, as plentiful as cockles. If you walk
down underneath a pier or a jetty when the tide is out, you will often
find that the pillars which support it are covered with great clusters
of these creatures; and very often the rocks which are left dry at
low-water are covered with them in just the same way. They fasten
themselves down by means of a bundle of very strong threads, which we
call the “byssus”; and these hold so firmly, that although the waves
may beat upon a bed of mussels day after day all through the year, they
never succeed in tearing them away.
Near the town of Bideford in Devonshire, indeed, there is a bridge
which is only kept standing by means of mussels. This bridge, which
is a very long one, with twenty-four arches, runs across the Towridge
River, close to the place where it joins the Taw; and the tide runs so
rapidly that if mortar is used to repair the bridge it is very soon
washed away. So boat-loads of mussels are brought to the bridge from
time to time, and these anchor themselves down so firmly by means of
their byssus threads that they actually hold the stone-work together!
Sometimes, however, mussels do a great deal of harm, for they will get
into an oyster-bed and fasten themselves down upon the shells of the
oysters. Their byssus threads then form a kind of thick mat, which
collects and holds the mud that is brought up by the tide every time
that it rises; and this very soon covers the oysters entirely up, and
smothers them to death.
Mussels do not remain fastened down in one place for the whole of
their lives, however, as oysters do. They can crawl about quite easily
whenever they like. And they do this, also, by means of their byssus
threads. First they move a few of these threads forward, and take a
fresh hold with them; then they draw the rest up after them; and then
they move the front ones forward once more, and so on over and over
again.
Mussels are very largely used for food, and also as bait for deep-sea
fishing. In the Firth of Forth alone, indeed, nearly forty millions of
these creatures are collected every year for this latter purpose alone,
or one for every man, woman, and child in England and Scotland and
Wales!
PLATE XIV
THE HORSE MUSSEL (3)
This is not a very handsome creature, for its shell is covered all over
with a rather thick brown skin, which is very much wrinkled. It is
quite common in many places, and yet one does not very often see it;
for it is nearly always hidden underneath its byssus threads, which
grow in thick masses. Besides this, it often burrows underneath the
surface of the sand; so that unless you know just _where_ to look for
it, and _how_ to look for it, you are not likely to find it.
[Illustration: PLATE XIV
1. INSIDE OF MUSSEL SHELL.
2. THE MUSSEL.
3. THE HORSE MUSSEL.]
But if you go down to the pools at the very edge of the water when
the tide is quite low, and scrape away the sand which is heaped up
against the bottom of the rocks, you may very likely come upon quite a
large cluster of these curious creatures.
Horse mussels are not used for food as common mussels are, because they
have a very strong and unpleasant taste.
PLATE XV
THE VARIABLE SCALLOP (1)
A good many different kinds of scallops are found on our shores. One
of them--the Common Scallop--is as large as the palm of a man’s hand,
and is used for food. You may often see it in fishmongers’ shops. But
you are not at all likely to find its empty shells lying on the shore,
for it lives in rather deep water. You may find those of the Variable
Scallop, however, very often indeed in places where the shore is sandy.
It is called the “variable” scallop because it varies so much in colour
that one hardly ever sees two of its shells which are quite alike.
Sometimes they are crimson, sometimes pink, sometimes mauve, sometimes
dark yellow, sometimes golden yellow, and sometimes blotched and
mottled with different colours. A number of ridges run down the shell
from the hinge to the margin, and on each of these is a row of short
spikes; so that the animal looks something like a tipsy-cake!
Scallops swim in a rather curious way, namely, by opening and shutting
their valves over and over again. As often as they do this a jet of
water is squirted out, and this acts on the surrounding water just like
the jets which are squirted from the siphon tubes of the cuttle, and
drives the animal along with some little speed. As it travels through
the water it looks very pretty, for all round the edges of its shell it
has a fringe of long feelers, which wave up and down in a most graceful
way. By means of these it obtains its food. At the base of these
feelers is a row of little black dots, which seem to be eyes.
PLATE XV
THE RADIATED SCALLOP (2)
This is rather a rare shell, and if you find it lying upon the shore
you will be fortunate. You may know it at once if you _do_ find it, for
it only has six or seven ridges running down it, instead of about twice
that number. It varies a good deal in colour, but is generally reddish
brown, spotted and speckled with white.
[Illustration: PLATE XV
1. THE VARIABLE SCALLOP.
2. THE RADIATED SCALLOP.
3. THE HUNCHBACK SCALLOP.]
PLATE XV
THE HUNCHBACK SCALLOP (3)
It is very easy to see why this creature is called the “hunchback,” for
although when it is quite small it is shaped just like other scallops,
it alters in form very much as it grows bigger; so that really it
sometimes looks as if it had been crumpled up when it was quite soft,
and had never recovered from the squeeze. Besides this, the two valves
are not alike, as they are in other scallops, for while one is always
very deep and rounded, the other is nearly flat. So when the animal
is alive it really has a kind of “hunchbacked” appearance; and if you
found its two valves lying apart from one another you would hardly
believe that they could both have belonged to the same creature.
The colour of the hunchbacked scallop is white, mottled with brick-red.
PLATE XVI
THE SUNSET SHELL (1 and 2)
This is a very “local” shell. That is, it is very common indeed in
some places, so that you might pick up hundreds and hundreds in a few
minutes, while in other places it is never found at all. The best place
in which to look for it is a part of the beach where sand and mud are
mingled together, and there you will be almost sure to find it.
The name of “sunset” shell has been given to it because of the
beautiful way in which the inside surface is coloured. Sometimes it is
rosy pink all over; sometimes it is orange yellow; sometimes it has
crimson streaks upon a whitish ground. But you can never look at it
without being reminded of the evening sky after a very bright sunset.
The outside of the shell, however, is always white and chalky-looking,
and no one who saw the two valves fastened together as they are when
the animal is alive would have the least idea how beautiful they really
are.
This creature always lives buried in the sandy mud, just as the cockle
does. It has a very powerful “foot,” by means of which it burrows, and
two long and very slender siphon tubes.
PLATE XVI
THE GAPER (3)
This is another of the shell-bearing molluscs which live in burrows in
the sandy mud, and it is called the “gaper” because the shells are
always open at the top, just as if the animal were yawning, or gaping.
Through this opening the siphon tubes project. These tubes are used in
breathing, just like those of the cuttle, and are enclosed in a kind of
leathery case, which the animal can stretch out or draw back at will;
so that when it is lying at the bottom of its burrow it can keep the
tips of the siphon tubes just above the surface of the mud, and so draw
water down to its gills quite easily.
[Illustration: PLATE XVI
1. INSIDE OF SUNSET SHELL.
2. THE SUNSET SHELL.
3. THE GAPER.]
On some parts of the coast gapers are used as food. But if you want
to buy some you must not call them “gapers.” You must call them “old
maids”; for by that name they are always called by the fishermen.
Some of the sea-birds are very fond of them too, and dig them out of
their burrows with their long beaks. And in the far North millions and
millions of them are devoured by walruses, and also by Arctic foxes,
which prowl about the shore in search of them every day when the tide
goes down.
PLATE XVII
THE PIDDOCK (1)
Now we come to one of the most wonderful of all the creatures which
live in the sea; namely, the Piddock. You can find its empty shells
lying about in numbers on almost any part of the shore where the cliffs
are made of chalk or limestone. And if you look at the rocks which are
left dry when the tide goes down you will see the entrances to its
burrows--large, oval holes, several of which you may often find quite
close together. For the piddock is a boring shell, which drives its
tunnels through and through the rocks, until very often they are quite
honeycombed by its tunnels. Sometimes you may meet with a big block of
chalk which only weighs about half as much as it should, because all
the rest has been cut away by piddocks. And if you could split it open
you would find several of these creatures lying in their burrows.
But how they manage to cut their way through the hard chalk, or the
still harder limestone, nobody quite knows. Most likely, however,
they do so partly by means of the soft part of the body which we call
the “foot,” and partly by means of the shell, which they turn first a
little bit to one side, and then a little bit to the other side, just
like a man who is using a bradawl. Every now and then, of course, the
burrow gets choked up with the material which has been scraped away.
But the piddock knows quite well what to do in order to clear it. It
just squirts out a jet of water from the siphon tubes, by means of
which it breathes, and so washes the burrow out!
Now let me tell you why I said that the piddock is one of the most
wonderful of all the creatures which live in the sea.
First of all, then, remember that the sea, acting by itself, has very
little power to wash away chalk. For as soon as the waves begin to beat
upon the face of a chalk cliff, they leave on it the spores, or seeds,
of sea-weeds. Very soon those spores begin to grow, and before long the
surface of the cliff is covered with masses of weed, so that the sea
hardly touches the chalk underneath them at all. The waves might beat
upon the cliffs for hundreds and hundreds of years without breaking it
down.
But the piddock comes and burrows into the chalk just below high-water
mark. Backwards and forwards it goes boring on, till at last only thin
dividing walls are left between its tunnels. Then the sea washes in,
and breaks down these walls, so that the whole foundation of the cliff
is cut away. The result is, of course, that before very long there is
a landslip. Hundreds of tons of chalk come tumbling down into the sea.
Then the piddocks begin work again a little farther back, and by-and-by
there is another landslip.
You can see the effects of the piddock’s work upon any part of the
coast where there are chalk cliffs. Just look at the beach when the
tide is out. You will notice long spits of weed-covered rocks, which
sometimes run far out into the sea. Well, those rocks were not always
rocks. They were once the bottoms of cliffs. But the piddocks and the
sea, working together, cut the cliffs down; so that the sea gained,
yard by yard, upon the land.
Indeed, I think that it may be said, quite truly, that if it had
not been for the work of the piddocks Great Britain would not be an
island! At any rate we do know this, that once, a great many hundreds
of thousands of years ago, Great Britain was not an island at all, but
was joined to the mainland of the Continent of Europe. And we also know
that the sea, acting by itself, could not possibly have cut a passage
through what we now call the Straits of Dover. The piddocks helped it
to do so! They kept on cutting away the foundation of the cliffs by
boring backwards and forwards through the solid chalk, just below the
level of the waves; and the sea finished the work which the piddocks
had begun, by breaking down the thin dividing walls between their
burrows.
PLATE XVII
THE LITTLE PIDDOCK (2 and 3)
The common piddock grows to a length of from three to five inches, and
is almost always white in colour, though sometimes it is stained by
the rocks in which it lives. But there is another kind of piddock
which is very much smaller, for its shells hardly ever measure more
than an inch and a half in length, and are a good deal narrower in
proportion to their size. This creature is called the Little Piddock.
It is generally of a brownish yellow colour, and you may often find its
burrows in great numbers in limestone rocks.
[Illustration: PLATE XVII
1. THE PIDDOCK.
2. AND 3. THE LITTLE PIDDOCK.]
PLATE XVIII
THE SHIP-WORM (1 and 2)
This creature certainly does not look in the very least like a mollusc;
and I do not think that anybody who had never seen it before would ever
guess that it is really quite a near relation of the piddocks. It looks
much more like a kind of worm, for it has a soft round body no larger
than an ordinary drawing pencil, though it is often as much as ten or
even twelve inches in length. But if you were to look at the head end
of its body you would see its bivalve shells, though they are so very
small that they might easily be mistaken for jaws. And these would show
you that the animal is really a shell-bearing mollusc.
The shipworm is a most mischievous creature, for instead of burrowing
into chalk or limestone rocks, like the piddocks, it bores into
timber, such as the hulls of ships, and the posts which support jetties
and piers. Very often it cuts away more than half the wood in a great
beam, leaving only the thinnest walls between its tunnels. And as it
works along it lines these tunnels with a curious shelly substance,
which strengthens them and prevents them from breaking down.
By burrowing into timber in this way the shipworm often does most
terrible damage. But it seems to dislike the taste of iron rust very
much indeed. So when a beam of timber has to be protected from its
attacks, a number of iron nails with very broad, flat heads are driven
into the surface, with only the space of an inch or two between them.
The salt-water acts upon these very quickly, and the result is that
the whole of the beam is very soon covered over with a thin coating of
rust, so that no shipworm will attempt to touch it.
[Illustration: PLATE XVIII
1. THE SHIP-WORM.
2. WOOD BORED BY SHIP-WORMS.]
When the shipworm is quite small it is not in the least like the
perfect animal. Indeed, if you were to see a baby shipworm, I do not
think that you would ever guess what it was. It is really a kind of
shipworm caterpillar. In shape it is nearly round, and is covered
almost all over with tiny hair-like organs, by means of which it swims
in the water. But the odd thing about it is that it keeps on changing
its form. After about thirty-six hours it becomes oval. A few hours
later, if you were to look at it again, you would find that it was
almost triangular. A few hours later still it would be round again,
just as it was when it first hatched out of the egg. And during this
time of its life it has a strong fleshy “foot,” like that of a snail,
so that if it becomes tired of swimming it can settle down and crawl
about on the surface of the rocks.
Have you ever been through the Thames tunnel? If you have, you will be
interested to know that it is made just like a shipworm’s burrow, for a
kind of boring instrument, called a “shield,” was made, which enabled
the workmen to line the walls with masonry as fast as the earth was
cut away. In this way the walls were prevented from falling in, and
water from the river above was kept from breaking through the roof and
flooding the tunnel. And Brunel, the great engineer who constructed
the tunnel, admitted that the idea had come to him one day when he was
examining the burrow of this wonderful mollusc.
PLATE XIX
THE RAZOR (1 and 2)
If you walk about very quietly, when the tide is out, on the stretch of
wet, sandy mud which lies just above low-water mark, you may often see
a very curious object resting at the surface, and looking just like a
little key-hole. And if you step heavily anywhere near it, it is almost
sure to squirt up a little jet of water into the air and disappear.
Then you may be quite sure that you have found the burrow of a Razor
Shell.
This is a very long, narrow creature with bivalve shells, which are
shaped almost exactly like the handle of a razor. It is generally about
four or five inches in length and half-an-inch in width, and the object
which looks so like a key-hole consists of its siphon tubes, the tips
of which rest just above the surface of the sand when it is lying at
the mouth of its burrow. It digs by means of its strong, fleshy “foot,”
just as the cockle does, and its burrow, which goes straight downwards
just like a well, is often as much as two feet deep. So it is not a
very easy thing to get a razor out of its tunnel. But if you want to
do so I can tell you how to manage it. Just take a good big pinch of
salt, and drop it down into the hole. Now the razor does not like salt
at all, even though most of its life is spent at the bottom of the
salt-water, and it comes up to the mouth of its burrow in a great hurry
to get rid of it. Then if you make a very quick stroke with a spade you
can dig it out before it has time to get down to the bottom again. But
if you should fail to get it up at the first attempt it is of no use
to try again, for even if you pour down a whole handful of salt the
animal will never come up a second time.
[Illustration: PLATE XIX
1. THE RAZOR.
2. TOP OF RAZOR FROM FRONT.
3. THE SABRE RAZOR.]
The razor is very good to eat, if its tough leathery skin is slipped
off, and on some parts of the coast it is often used for food. The
fishermen use it for bait, too, and catch it by means of a slender iron
rod with a barbed tip, which they thrust into its body as it lies at
the bottom of its burrow.
PLATE XIX
THE SABRE RAZOR (3)
There are several different kinds of Razors, and one of them is called
the “sabre razor,” because its shells are curved, just like the
scabbard of a sabre. It is fairly common, but you are never likely to
find its burrows, unless you go to look for them just at low-water
after a spring-tide, because it almost always lives below the ordinary
low-water mark. But after spring-tides--which come twice in every
month, once when the moon is new and once when it is full--the waves
retreat much farther than they do at other times. Then, if you go right
down to the water’s edge, you may often find creatures which you will
never meet with higher up on the beach. And one of these is the sabre
razor.
PLATE XX
THE PINNA
This is the largest of all the shell-bearing molluscs which live in
our British seas, for it has been known to reach a length of nearly
two feet. It is found chiefly on our southern coasts, and always lies
upright, half buried in the mud at the bottom of the water, with its
shells partly opened. And it always fastens itself down by a bunch of
“byssus” threads, like those of the mussel, which are so strong that it
takes a very hard pull indeed to tear them away from their hold.
In the British Museum you may see a pair of gloves which have been made
out of the byssus threads of a pinna, and if these creatures were more
plentiful their threads would no doubt be used in this way very largely
indeed.
Now why do you think that the pinna always rests at the bottom of the
water with its shells partly opened?
[Illustration: PLATE XX
THE PINNA.]
Well, the reason is a very odd one. It is setting a trap for fishes!
For fishes, as perhaps you know, are very inquisitive creatures. They
always want to know all about everything, and whenever they see a
hole they think that they must find out what is inside it. So when a
little fish comes swimming past a pinna, and catches sight of its
gaping shells, it is almost sure to venture in between them. Then the
shells close tightly, and it finds itself in a prison from which there
is no escape; and very soon it is killed and devoured.
In colour, the shells of the pinna are very pale brown, and a number
of ridges run down it from the smaller end to the larger. When the
animal is full-grown it is sometimes not at all easy to see its shells,
for they are covered almost all over with barnacles and the tubes of
sea-worms.
CHAPTER IV
CRABS
HOW CRABS GROW
If you hunt about in the pools among the rocks when the tide goes out,
and look behind the masses of sea-weeds which cover them, you are quite
sure to find a good many crabs of several different kinds. Before I
tell you about these, however, I think you would like to know something
about the way in which these curious creatures grow.
Remember, then, in the first place, that what we always call the
“shell” of a crab is not really a shell at all. That is, it is not in
the least like the shell of an oyster, or a periwinkle, or a cowry, or
a whelk. In these creatures the shell grows together with the animal
inside it, and is never thrown off all through their lives. But the
“shell” of a crab never grows at all. It is really a kind of crust
of lime on the outside of the skin, which will not even stretch in
the very least degree. So the only way in which crabs can grow is by
throwing off their “shells,” in order that the soft bodies underneath
may increase in size.
So once in every year, until it reaches its full size, every crab has
to cast off its shelly covering and get a new one in its place. A few
days before the change takes place it always goes and hides away in
some dark crevice among the rocks, or behind an overhanging mass of
sea-weed, where none of its many enemies are likely to find it. It
knows perfectly well, you see, that while it is without its coat of
mail it will be quite helpless; for its claws will be so soft that it
will not be able to use them, while its body will be quite unprotected.
Then a very strange thing indeed takes place. Something like a third
part of its flesh turns into water! If you were to catch the animal at
this time and to shake it, you would be able to hear the water swishing
about inside its shell! Then it gets very restless indeed, and begins
to wriggle about a good deal, turning and twisting from side to side,
and rubbing its legs against one another, till it is quite tired out.
It then rests for a little while, and begins to wriggle and twist
about again. The fact is that it is trying to get loose, as it were,
inside its “shell.” After a time it succeeds in doing this, so that the
“shell” is no longer fastened to its body at all. Then, quite suddenly,
a rent opens right across its back, and the crab gathers itself
together and leaps, with a mighty effort, right out of its old coat!
And as soon as it has done so the rent closes up again, so that unless
you look very carefully indeed you cannot see it. You might really
think that two crabs were lying side by side together.
For about a couple of hours the crab now lies perfectly still; and if
you were to feel it you would find that its body was hard and knotted
all over. That is because its muscles are cramped after the violent
efforts which it has been making. After a time, however, the cramp
passes off. Then the animal begins to grow. It grows very fast indeed.
In fact it grows so fast that you can almost see it growing, and in
less than twenty-four hours it is sometimes nearly half as big again as
it was before. A new “shell” then begins to form upon the skin, and in
about a couple of days more the animal is able to leave its retreat,
clothed once more in a suit of good stout armour.
That is the way in which crabs, and lobsters, and shrimps, and prawns
all grow. Once in every year at least they get new “shells”; and every
time that they do so they increase in size. But after they reach a
certain age they grow no more; and the coats of mail which they are
wearing then are kept to the end of their lives.
HOW CRABS SEE
Perhaps, too, you would like to know something about the eyes of crabs;
for these creatures see in a very odd way. On each side of the head is
a kind of stalk, something like those which you may see on the heads
of slugs and snails, only very much smaller. And at the tip of each
stalk is a small black spot. Now if you were to put one of these little
stalks under the microscope, and to look at the black spot, you would
find that it was made up of hundreds and hundreds of very tiny eyes,
very much like those of insects, except that instead of being six-sided
they are square. So that altogether, perhaps, a crab may have three or
four thousand eyes, or even more!
That sounds a very large number, doesn’t it? But then, you see, a crab
cannot move its eyes up and down, and from side to side, as we can.
They are fixed, and cannot be moved at all. Each eye, however, looks in
rather a different direction from all the rest. Some eyes look upwards,
some look downwards, some look forwards, some look backwards, and some
look out on either side. So without moving its head at all the crab is
able to see all round it.
Think of it in this way.
Suppose that you take a telescope and look through it. You can only
see the objects at which the telescope is pointed, not the objects
above it, or below it, or on each side. But if you had four thousand
telescopes, fastened together in two bundles of a couple of thousand
telescopes each, all pointing in different directions, _and if your
eyes were made in such a way that you could look through all the
telescopes at once_: then you would be able to see all round you,
though you would only be able to look in any special direction through
just one or two of the telescopes.
Now that is very much like the way in which the eyes of crabs are made.
Each of these four thousand eyes is really a kind of telescope. And as
they all point in different directions, the crab is able to see above
it and below it and on all sides, though it only looks at any special
object through one or two eyes.
HOW CRABS HEAR AND SMELL
The way in which crabs hear and smell is almost as curious as the way
in which they see, for they have very odd little ears and noses in very
odd places.
On its head, as perhaps you know, a crab has two pairs of feelers. We
call them the “lesser feelers” and the “greater feelers.” Now if you
were to look at the first joint of the lesser feelers through a good
microscope, you would find on each a little gland, or bag, containing a
very tiny drop of salt and water. These are the crab’s ears. Of course
they are not nearly so good as our ears are. Indeed, I do not think
that a crab can hear sounds in the air at all. But water carries sounds
much more readily than air does, so that if you were to dive into a
lake, or into the sea, on a calm, still day you could easily hear the
beat of the oars in a boat half a mile away. And the ears of the crab
are made in such a way that they can hear sounds in the water quite
well, even though they may be deaf to sounds in the air.
Then if you look at the first joint of the greater feelers through the
microscope, you will see two other tiny glands. These are the crab’s
noses, by which it can smell odours in the water just as we can smell
odours in the air. It always seems to find its food by scent, and if
one of those basket-like traps which we call crab-pots is baited with
a few pieces of decaying fish and lowered into the sea, crabs will
smell the bait from quite a long distance away, and come hurrying up
to obtain a share in the banquet. And they seem to do so by means of
those odd little noses on the lower joints of their greater feelers.
PLATE XXI
THE EDIBLE CRAB
Now let me tell you something about the different kinds of crabs which
you may find on the shore.
First of all, of course, there is the Edible Crab. This is the crab
which is so largely used for food, and which you may see in any
fishmonger’s shop. Sometimes it grows to a very great size, and has
claws so big and strong that if it were to seize a man by the wrist he
would find it very difficult indeed to set himself free. You will not
find crabs as big as this among the rocks, for these giant creatures
always live in rather deep water. But one often discovers a crab four
or five inches across hiding in a rock-pool, and even he is quite big
and strong enough to give one a very sharp nip.
[Illustration: PLATE XXI
THE EDIBLE CRAB.]
It is rather amusing to get one of these crabs out on to the open sand,
and then to stand just in front of him. He will at once raise both his
great claws and hold them in readiness to strike at you if you attempt
to seize him. Then if you walk slowly round and round him he will
turn round and round too, so as to keep facing you, over and over
and over again. And if you put your hand anywhere near him he will snap
at it so quickly that it is really not at all easy to avoid his stroke.
Edible crabs often have their shells covered with barnacles and the
tubes of some of the sea-worms. Old crabs, indeed, which no longer
change their coats of mail every year, are often so covered with these
creatures that one can hardly see their shells at all.
PLATE XXII
THE SHORE CRAB (1)
This is sometimes known as the Green Crab, because it is generally
more or less green in colour. But you may often find examples, which
are deep brown all over, while others are bright yellow, with black
markings upon their backs. It does not grow to nearly such a great size
as the edible crab, and although its flesh is quite good to eat there
is so little of it that the animal is hardly ever used for food. But it
is wonderfully strong, and if you find a green crab hiding beneath a
big stone or behind a mass of sea-weed, you must be very careful not to
get a nip from its claws.
The green crab spends a great part of its life out of the water, for
its gills are made in such a manner that they will keep moist for a
very long time. And as long as its gills are damp a crab can breathe
quite as easily on land as if it were in the sea. It is very active,
and if you go down near the water’s edge while the tide is coming in
you may often see it hunting sandhoppers and even flies, creeping up
to them very carefully until it is only a few inches away, and then
pouncing upon them so suddenly that they have no time to escape. And it
is often very troublesome to fishermen, for it will seize their bait
with its strong nippers, and pull it off the hooks before a fish is
able to take it.
This crab is very easily kept in confinement, and will soon become
quite tame, so that it will even come and take food from your fingers
just like a dog. But you must be careful to pile up a few stones in the
water in which you keep it, so that it may sit upon them and take an
airing whenever it feels inclined. And it will even enjoy an occasional
run about the room.
[Illustration: PLATE XXII
1. THE SHORE OR GREEN CRAB.
2. THE FIDDLER CRAB.]
PLATE XXII
THE FIDDLER CRAB (2)
The crabs about which I have been telling you live in the sea, though
they often leave it for some little time and run about on the shore.
But none of them can swim, and if they are thrown into deep water they
just sink to the bottom with their legs sprawling, feeling about for
some object to which they can cling. Sometimes, however, if you look
into one of the pools which are left among the rocks when the tide
goes down, you may see a small crab swimming through the water with
some little speed. This is quite sure to be a Fiddler Crab, and if you
catch it and examine its hinder legs, you will find that instead of
being quite slender, with hooked claws at the tips, as they are in most
crabs, they are flattened out into broad, oval plates. And you will
also find that these plates have a fringe of rather long hairs growing
all round them.
Now these are the paddles with which the crab rows itself through the
water, and it is called the “Fiddler Crab” because the movements which
it makes with them are rather like those of a man who is playing the
violin. You can easily keep it in an aquarium, and a very interesting
little pet it makes. But you must remember that it is a very savage
little animal, and will certainly do its best to kill any other
creatures that you may put into the same vessel. Even if you put two
fiddlers together they are almost sure to fight; and the one which wins
the battle will kill and eat the one which loses it.
When the Fiddler Crab is alive it is really a very handsome little
creature, for its blackish shell is covered all over with soft, short
down, looking rather like velvet, while its legs are striped with blue,
and its claws are partly blue and partly scarlet.
PLATE XXIII
THE MASKED CRAB (1)
The broad shelly shield which covers the back of a crab is called the
“carapace,” and there are certain markings upon it which are rather
like the features of a human face. But there is one crab in which
these markings are so deep and strong that it looks just as if it were
wearing a mask. So it is always known as the “Masked Crab.” It is found
on the southern and western shores of England and Wales, and you may
always know it if you meet with it, not only because of the face-like
markings upon its back, but also because its carapace is a good deal
longer than it is broad, whereas in other crabs it is nearly always
broader than it is long. Besides this, the great claws are not really
“great” at all, for they are very long indeed and very slender, with
quite small nippers at the tips, while the greater feelers are quite as
long as the claws. So altogether the masked crab is a very odd-looking
crab indeed. But if you want to find it you will have to look for it
very carefully, for it has an odd way of burying itself in the sand,
and only leaving just its feelers and its eyes above the surface.
PLATE XXIII
THE THORNBACK CRAB (2)
This is perhaps the very oddest of all our British crabs.
In the first place, it looks much more like a big spider than a crab;
for its body is very small, while its legs are very long and very
slender. Indeed, the group of crabs to which it belongs is often called
“spider crabs” in consequence. In the second place, its carapace is
covered all over with rather long sharp spikes, which project in all
directions, so that it strongly reminds one of a tipsy-cake! And, in
the third place, the crab nearly always has a number of tufts of
sea-weed or sponge growing upon its back.
Perhaps you might think that these come there by accident. But they
do not. The crab himself plants them there! If you keep him in an
aquarium you may often see him doing so. First of all he turns one of
his long claws over his back and scratches away at the carapace, so as
to roughen the surface. Then he pulls up a little sprig of sea-weed
or sponge and actually plants it on his shell, pressing the rootlets
firmly down. And besides the spikes upon the shell there are numbers
of tiny hooks, which help to hold it in position. Then the crab plants
another piece of weed or sponge in just the same way, and so he goes on
planting piece after piece until his back is completely covered.
Now why do you think he takes all this trouble?
Well, the reason is that he does not want to be seen; for he has a
great many enemies, and he knows perfectly well that if he were to lie
among the sea-weeds or sponges at the bottom of the sea they would be
quite sure to notice him as they passed by, and then he would almost
certainly be killed and eaten. So he clothes himself with either
sea-weeds or sponges, as the case may be, and then feels that he is
perfectly safe, and that as long as he keeps quite still even the
sharpest eye will fail to notice him. And if you catch one of these
crabs which is covered with sea-weeds and put it into an aquarium in
which sponges are growing, it will very soon strip the weeds off its
back and cover itself with sponges instead; while if you catch one that
is covered with sponges, and put it into a tank in which sea-weeds are
growing, it will strip off the sponges and cover itself with sea-weeds!
[Illustration: PLATE XXIII
1. THE MASKED CRAB.
2. THE THORNBACK CRAB.]
The thornback crab often grows to a rather large size. Indeed, next to
the edible crab, it is the largest of all the crabs which are found
in our British seas, for its carapace is sometimes as much as eight
inches long and six inches wide, while its great claws may be fourteen
or fifteen inches in length. On some parts of the coast it is used for
food, but its flesh is rather coarse and of poor quality.
PLATE XXIV
THE LONG-BEAKED SPIDER CRAB (1)
This crab has an even smaller body in proportion to its size than the
thornback, and its legs are so very long and so very slender that they
remind one of those of a daddy-long-legs. Its carapace is drawn out
in front into a kind of beak, which is quite as long as the carapace
itself, and while the crab is alive it is of a most beautiful pink and
puce colour. It is not a very common creature, but is sometimes to be
found in the rocky pools near low-water mark on our southern coasts,
and is covered, very often, with sea-weeds or sponges, just like the
thornback.
PLATE XXIV
THE FOUR-HORNED SPIDER CRAB (2)
Perhaps this is the commonest of the British spider crabs. Indeed, it
is so plentiful at Bognor, and at other places on the southern coast
of England, that when a crab pot is taken out of the water as many
as twenty or even thirty of these creatures are sometimes found in
it. They are called by the fishermen “sea-spiders,” and are generally
so clothed with those odd sea-weeds called “corallines” that you can
hardly see any part of their “shells” at all.
In this crab the carapace is drawn out in front into a very long beak
indeed, which has four horns upon it, and the whole upper surface is
covered with short, sharp spikes and stout hairs.
[Illustration: PLATE XXIV
1. THE LONG-BEAKED SPIDER CRAB.
2. THE FOUR-HORNED SPIDER CRAB.]
PLATE XXV
THE PEA CRAB (1)
This is a very odd crab indeed. In the first place it is extremely
small. Even when it reaches its full size it is scarcely ever so much
as half-an-inch across, while its body is so round that it really does
remind one very much of a pea. Only it is not quite the right colour
for a pea, for it is creamy yellow instead of green.
And, in the second place, this crab lives in a very odd place--namely,
inside the shells of living mussels, or pinnas, or even cockles! What
it does there nobody seems quite to know. It does not appear to injure
the animal to whom the shell belongs, although it is very fond of the
flesh of mussels, and if it finds one of those creatures lying dead
will certainly devour it. Perhaps it only creeps inside its shell for
the sake of safety. At any rate, it is a very timid little crab, and
if you open a mussel and find a pea crab lying hidden inside it, it
will tuck up all its legs quite close to its little round body and lie
perfectly still for several minutes in the hope that you will think
that it is dead.
On some parts of the coast pea crabs are so plentiful, that three out
of four mussels are found to have one of these odd little creatures
inside it.
PLATE XXV
CRAB CATERPILLARS (2 and 2 A)
I dare say you did not know that crabs have caterpillars, just as
insects have. We call these crab caterpillars “zoeas,” and they are
not in the least like their parents. There are a great many different
kinds, of course, for every crab has its own zoea, just as every
butterfly and moth has its own caterpillar, and some of them are not
very much like some of the others. But they are always very tiny
indeed--they are scarcely as large, in fact, as the smallest grains of
sand--and they always have a very long curved horn in front of the body
and another one behind, and long waggly tails. And they swim in the
oddest way possible--by turning somersaults in the water, over and over
again!
These zoeas are very useful little creatures, because they feed upon
the tiny scraps of decaying matter which are always floating about
in the sea, and so help to keep the water always pure. They belong,
in fact, to the great army of what I always like to call “nature’s
dustmen”--those little animals whose duty it is to clear away the
rubbish from the world. There are millions and millions of these busy
little workers on the land, and millions and millions of others in
ponds and rivers, as well as in the sea, and so well do they perform
their task that both the air and the water are always kept pure.
Another very interesting fact about zoeas is that they form the chief
food of no less a creature than the Greenland whale. No doubt you know
that whales are of two kinds--those which have teeth, and those which
have none. Those which have teeth feed upon fishes, and giant cuttles,
and could easily swallow a man. But the whales which have no teeth
have throats so small that they would almost certainly be choked if
they tried to swallow a herring! So they have to feed on very small
creatures indeed, and are very fond of zoeas, which often swim about in
such vast shoals that the water of the sea is quite thick with them.
And they catch them in a most curious manner.
You have heard, of course, of the very useful substance which we call
“whalebone;” and no doubt you know that it has nothing to do with the
bones of the whale at all. It is found in the mouths of those whales
which have no teeth, and hangs down in great plates from the gums of
their upper jaws. Very soon these plates split up; and then each part
splits up again; and so on, over and over again, till at their lower
ends they form a kind of thick fringe of close, matted hairs.
Now it is by means of this fringe that the whale catches the zoeas.
When it meets with a shoal of these little creatures it opens its huge
mouth wide, and swims through them. Then it nearly closes its jaws, and
lets down the whalebone plates, so that the hairy fringe forms a kind
of strainer all the way round. It then squirts out the water from its
mouth through this fringe, which allows the water to pass through it,
but keeps back the zoeas; and when it has got rid of all the water it
closes its mouth completely and swallows the zoeas, a few thousand at a
time, after which it opens its jaws again, and swims through the shoal
once more.
Doesn’t it seem strange that the biggest animal on earth should feed on
some of the very smallest?
PLATE XXV
CRAB CHRYSALIDS (3 and 3 A)
When the caterpillar of an insect has reached its full size it throws
off its skin and appears as a chrysalis, or pupa. And the caterpillar,
or zoea, of a crab does exactly the same thing. It casts its skin, and
appears in quite a different form. Only we do not call it a chrysalis,
as a rule. We call it a “Megalopa.”
[Illustration: PLATE XXV
1. PEA CRAB (life-size).
2. CRAB CATERPILLAR (enlarged).
2A. ” ” (life-size).
3. CRAB CHRYSALIDS (enlarged).
3A. ” ” (life-size).]
The word “megalopa” means “a creature with big eyes,” and it is given
to the crab chrysalis because it has eyes which are enormously big
in proportion to the size of the head. They are set on long footstalks,
which project on either side, so that the head looks rather like a
hammer. Then the long curved horns which the zoea had are to be seen no
longer, and the carapace is shaped much more like that of the perfect
animal, while the great claws begin to show, and the legs increase in
length. The tail, however, is still quite free, like that of a lobster,
and the little animal still swims by turning somersaults in the water,
and lives on the same tiny scraps of decaying matter on which it fed as
a zoea. After a few weeks it throws off its skin once more, and appears
in the world as a perfect crab.
PLATE XXVI
HERMIT CRABS (1 and 2)
If you go down among the rocks when the tide is out, and hunt about in
the pools, you may often find the shell of a whelk in which a small
crab is living, with one of his great claws carefully guarding the
entrance. This is a Hermit Crab, and a very curious little creature he
is. For, in the first place, his long tail is quite free, like that of
a lobster, instead of being fastened down to the lower surface of his
body; and in the second place, it is quite soft, without any shelly
covering at all. His body and limbs are covered with armour, just like
those of other crabs, but his tail has none at all.
The consequence is that the hermit crab always has to take the very
greatest care of his tail. He is so dreadfully afraid that one of
his many enemies will come up behind and give it a nip when he isn’t
looking! So he protects it by tucking it away into the empty shell of a
whelk. He never leaves this shell, but drags it about with him wherever
he goes. And if you take hold of him and try to pull him out, you will
find that you cannot do so without injuring him very badly. For at the
end of his tail he has a pair of strong pincer-like organs, with which
he holds on so firmly that it is very difficult indeed to make him let
go.
Indeed, the only way to get a hermit crab out of his dwelling is to put
him, shell and all, into the spreading arms of a big sea anemone. That
frightens him almost out of his wits, for the arms of the anemone at
once come closing in, and he knows quite well that if he stays where
he is he will very soon be swallowed. So he skips out of the shell and
scampers away as fast as he possibly can, leaving the empty shell in
the anemone’s clutches.
[Illustration: PLATE XXVI
1. THE HERMIT CRAB IN WHELK-SHELL.
2. THE HERMIT CRAB OUT OF SHELL.]
The poor little animal is now perfectly miserable. He has no protection
for his tail, you see, and goes hunting about everywhere for some
other shell into which he can tuck it. After a while, perhaps, he finds
that of a periwinkle. It is not of much use, of course, for it is so
small that he can only get just the tip of his tail into it. Still, it
is better than nothing, and he goes crawling about with the periwinkle
shell on the end of his tail, like a thimble on the tip of one’s
finger, in search of a bigger one. By-and-by he discovers one. Then he
whips his tail out of the old shell and into the new one so quickly
that you can hardly see how he does it, and goes off to look for a
bigger shell still. And in this way he will change his dwelling perhaps
half-a-dozen times before he is really satisfied.
Sometimes you may find a hermit crab with a sea anemone fastened to
the edge of the shell in which he is living. That seems strange,
doesn’t it, when you remember how terribly afraid the little animal
is of anemones. But in such a case the anemone never interferes with
the hermit crab, and the crab never interferes with the anemone, while
both of them benefit by the arrangement. The crab benefits, because
no fish will ever touch him so long as an anemone is attached to his
whelk-shell. There are plenty of fishes which would be quite ready to
gobble him up, whelk-shell and all, if it were not for this creature.
But fishes know quite well that sea anemones can sting, and therefore
never think of devouring them, no matter how hungry they may be; so
that so long as an anemone is guarding the whelk-shell in which he
lives, the hermit knows that he is perfectly safe. And the anemone
benefits, because it gets a share of the crab’s meals. When a hermit
crab finds the dead body of some small creature at the bottom of the
sea he pulls it to pieces and devours it; and as he does so a quantity
of tiny scraps are sure to come floating upwards, and are seized by the
outspread arms of the anemone. So the crab gets the big pieces, and the
anemone gets the little ones; and both are perfectly satisfied.
CHAPTER V
LOBSTERS AND THEIR KIN
PLATE XXVII
THE LOBSTER
You are not at all likely to catch a lobster for yourself, for these
creatures live in deep water, and are only to be taken by means
of proper lobster-pots. But I must not pass the animal by without
mentioning it at all, for at any rate you will be quite sure to see it
on the slab of every fishmonger’s shop.
Of course you know that a lobster is not red until it is boiled, but
is nearly black all over. And of course you know, too, that one of its
great claws is always a good deal larger and stouter than the other.
Sometimes people think that the reason of this is that at some previous
time the animal had lost one of his claws through some accident, and
was growing a new one, and that the new limb had not yet had time to
reach its full size. However, this is not the case, for one claw of
a lobster is always a good deal bigger than the other; and the real
reason is that the two claws are used for different purposes. The
larger claw is a weapon, with which the animal fights, while the
smaller one is an anchor, with which he clings to the weeds which grow
on the rocks at the bottom of the sea. And very often one is quite
twice as big as the other.
Now I wonder whether you know how a lobster uses his tail. He employs
it in swimming, and if you look at it you will find that it is made of
several broad, flat plates, which can be spread out very much like the
joints of a fan. You will notice, too, that these joints have a fringe
of hairs growing all round them. Now when a lobster swims he just
stretches his body straight out, and then doubles it suddenly up. As
he does so the plates of the tail spread out, and form a kind of very
broad and powerful oar, which strikes the water with such force as to
drive the animal swiftly backwards. With a single stroke of its tail,
indeed, a lobster can dart to a distance of forty or fifty feet, and
that so quickly that even the swiftest fishes could scarcely overtake
him.
Sometimes, however, a lobster swims forwards; and he does this by
means, not of his tail, but of five pairs of odd little organs
underneath the tail, which we call “swimmerets.” They spring from
either side of the soft hinges by which the joints of the tail are
fastened together, and each consists of two thin oval plates fringed
with long hairs. So each swimmeret really consists of two tiny paddles,
and by waving them to and fro in the water the lobster manages to
travel along with some little speed.
[Illustration: PLATE XXVII
THE LOBSTER.]
These swimmerets are used for another purpose as well, however, for
the mother lobster always glues her eggs to the hairs with which they
are fringed, and carries them about with her for some little time.
Haven’t you noticed, when you have had shrimps for tea, that a good
many of them had clusters of eggs underneath their bodies? Well, if you
had put one of those shrimps under a microscope, and examined it very
carefully, you would have found that every one of the eggs was firmly
glued down to one of the hairs on its swimmerets, where it would have
remained until it was hatched. And lobsters carry their eggs about with
them in just the same way.
PLATE XXVIII
THE PRAWN (1)
If you go down among the rocks when the tide is out, and look into the
shallow pools which have been left among them by the retreating waves,
you are quite sure to see numbers of shadowy forms darting to and fro
through the water. A good many of these will be prawns, and if you
catch one or two of them in a small net, and examine them carefully,
you will find that they are very much like tiny lobsters. Indeed, if
you could magnify a prawn to the size of a lobster, or reduce a lobster
to the size of a prawn, it really would not be very easy to tell the
one from the other.
But you will be surprised to see how different live prawns look from
the dead ones which you may see in a fishmonger’s shop. The fact is
that, like the lobster, they change colour when they are boiled. When
they are alive, indeed, they hardly have any colour at all, and are
nearly transparent. That is why it is so difficult to see them in the
water. And if you keep them in an aquarium, all that you can see of
them, very often, as they dart to and fro is just their glowing eyes,
which gleam in the water like tiny balls of fire.
There are two facts about prawns which I am sure you will be interested
to know.
The first is that they are extremely useful little creatures, for they
feed upon the bodies of the various small animals which die in the sea,
and so prevent them from becoming putrid and poisoning the water. And
the second is that they always take the greatest possible care to keep
themselves clean. If you take a few live prawns home, and put them in
an aquarium, you may often see them performing their toilets. Their
front legs are covered with stiff little hairs which stand out at right
angles, so that these limbs really form a pair of brushes. And with
them the prawn will clean its body most diligently, rubbing itself all
over until every little speck of dirt has been removed. And if any
object should cling to its body which these tiny brushes cannot rub
away, it will pull it off by means of the strong little pincers on the
second pair of legs.
Do you want to know how to tell a prawn from a shrimp?
Well, all that you have to do is to look in front of its head. There,
projecting from the edge of the “carapace,” or shield which covers the
back, you will see a long spike, something like a beak. Just put your
finger upon this, and feel the edge. If it is set with sharp little
teeth, like those of a saw, the animal is a prawn. But if the spike is
perfectly smooth, it is a shrimp.
PLATE XXVIII
THE ÆSOP PRAWN (2)
This is a much prettier creature than the common prawn, for its
transparent body is covered with scarlet lines, while its long
thread-like feelers have rings of the same colour round them at regular
distances apart. It is called the “Æsop” prawn because it has a big
hump on its back, just like the writer of the famous fables.
If you want to catch an Æsop prawn you must look for it in the summer,
for it always spends the rest of the year in deeper water. But as soon
as the weather becomes really warm it travels up and down with the
tide, and you may find it in plenty in the pools which are left among
the rocks at low-water.
PLATE XXVIII
THE SHRIMP (3)
I told you that a good many of the shadowy forms which you may see
darting to and fro in the rock-pools are those of prawns. The rest are
quite sure to be shrimps, which are very much more common. Indeed,
in most of the rock-pools you will find at least ten shrimps for
every prawn. But they are very difficult to see, for they are partly
transparent when they are alive, so that they are scarcely visible
when they are swimming. And when they are resting at the bottom of the
pool their speckled bodies look almost exactly like the sand on which
they lie. Besides this, they have a way of nearly burying themselves,
by scooping out a kind of furrow with their hind limbs, sinking into
it, and then covering themselves with sand by means of their
feelers. So the fishermen often call them “sand-raisers.”
[Illustration: PLATE XXVIII
1. THE PRAWN.
2. THE ÆSOP PRAWN.
3. THE SHRIMP.]
PLATE XXIX
THE SANDHOPPER (1 and 1 A)
Commoner even than the shrimps are the Sandhoppers. On any sandy part
of the shore you may find them in thousands and thousands. If you walk
along the beach where the sand is dry, and step rather heavily, you
will see their holes opening all round you. If you walk along it where
it is damp, you will find that it is honeycombed with their burrows. If
you turn over a stone, or lift up a piece of sea-weed which has been
thrown up by the waves, twenty, or thirty, or forty of them will come
skipping out like so many tiny kangaroos. And if you walk near the edge
of the water when the tide is coming in you may often see them leaping
about in such vast numbers that they look just like a thick mist rising
for a foot or eighteen inches into the air.
Yet sandhoppers have so many enemies that it really seems wonderful
that any of them should be left alive at all. Nearly all the shore
birds feast upon them, and so do many of the land birds. Indeed, when
the tide is rising, you may often see a long line of birds standing
closely side by side together a few feet in front of the water’s edge
and gobbling up the active little creatures in thousands. Then the
shore crabs are very fond of them, and destroy thousands more. And even
when they are buried deeply in the sand they are not safe, for there is
a little beetle which goes down their burrows after them, and catches
and eats them there very much as a ferret catches a rabbit in its hole.
But it is just as well that they do not all get eaten, for sandhoppers
are very useful little creatures indeed. They feed upon the masses of
decaying sea-weed which are constantly flung up on the shore by the
waves. For they, too, belong to the great army of “Nature’s Dustmen,”
like the “zoeas” of the crabs and lobsters, and help to clear away
all kinds of rubbish which would poison the air and the water if it
were left to decay. Indeed, they will eat almost anything, and if
you were to tie up a number of sandhoppers in your handkerchief, and
leave them there for a few minutes, you would never be able to use the
handkerchief again; for you would find that their sharp little jaws had
nibbled it into holes.
If you watch a sandhopper carefully when it is skipping about, you will
find that it leaps by doubling its body up, and then straightening it
out again with a sudden jerk.
[Illustration: PLATE XXIX
1. SANDHOPPER (enlarged).
1A. ” (life-size).
2. SAND SCREW (enlarged).
2A. ” (life-size).]
PLATE XXIX
THE SAND SCREW (2 and 2 A)
If you follow the tide as it goes out on a still day, you will notice
that it leaves the sand quite smooth behind it. But if you come to
the same spot about half-an-hour later, you will often find that it
is marked by numbers of winding tracks, which look just as if they
had been made by worms. These, however, are the work of the Sand
Screw, a curious little creature which in many ways is very much like
a sandhopper. But instead of sinking its burrows almost straight
downwards into the sand, as sandhoppers do, it drives them along almost
as a mole does, just below the surface.
If you stand quite still for a few minutes near the water’s edge, when
the tide is going out, you may sometimes see this odd little creature
at work; for as it pushes its way along it raises the sand into a kind
of low tunnel, which generally falls in behind it, and so forms a
groove. And if you suddenly turn over the sand in front of the tunnel
you will find the little animal which was making it, and will see at
once why it is called the “sand screw.” For instead of skipping about
like a sandhopper, it will lie on one side and wriggle its way along
with a curious “screwing” movement, just as though it were trying to
bore its way into the sand.
PLATE XXX
ACORN SHELLS (1)
If you examine the rocks which are left dry when the tide goes out,
you will often find that they are covered almost all over with small
shells which look rather like those of tiny limpets. Only at the top of
each shell there is a little hole, from the margin of which a number of
ridges run down to the bottom. And these ridges are so sharp, that if
you happen to slip when you are wandering about among the pools, and
catch at a rock to save yourself, they will cut your fingers almost as
if they were knives.
These creatures are generally known as “Acorn Shells,” and I dare say
that you might think that they must be very closely related to the
limpets. But in reality they are much more closely related to the
shrimps and sandhoppers, though they look so very unlike them, and lead
such different lives. For while shrimps and sandhoppers are always
swimming or skipping about, the little animals which live inside these
acorn shells never move at all after they are a few days old, but
spend their whole lives fastened down to the surface of the rocks. But
there is this great difference between the two. When the eggs of a
limpet hatch, out come a number of very tiny limpets, just like their
parent in everything except size. But when the eggs of an acorn shell
hatch, the little creatures which come out from them are not like their
parents at all. They are “zoeas,” in fact, or acorn shell caterpillars;
and they do not reach their perfect form for some little time.
When these little “zoeas” first make their appearance in the world
they are able to swim about by means of three pairs of tiny feathery
legs, with which they paddle their way along through the water. And
they also have a round black eye in the middle of the body, with which
they can see quite well. Every two or three days they throw off their
skins, just as caterpillars do, and appear in new ones, which have
been gradually forming beneath. And each time that they do this their
shape changes. At last they are ready to take their perfect form. Then
each of the little creatures clings to the surface of a rock by means
of its feelers, and pours out a kind of cement, which hardens round
them, and anchors it firmly down. It then throws off its skin once
more, and appears in the form of an acorn shell just like its parent.
And, strange to say, it throws off its eye at the same time, and is
perfectly blind for the rest of its life!
If you look down into a shallow pool, the rocky sides of which are
covered with these acorn shells, you may often see a very pretty sight.
You may see the little animals fishing. Out from the hole at the top of
each shell comes a kind of little net, which sweeps through the water,
and is then drawn back into the shell. This net is really formed by the
limbs, which are fringed with long hairs, and as it passes through the
water it collects the little tiny scraps of decaying matter on which
the animal feeds.
You may find these acorn shells in great numbers, not only on the rocks
which are left dry when the tide goes out, but also on the wooden
beams which support piers and jetties. Indeed, these beams are often
so closely covered with the odd little shells that you cannot see the
surface of the wood at all. And very often they fasten themselves to
the shells of limpets and oysters, and even on the backs of crabs.
[Illustration: PLATE XXX
1. ACORN SHELLS.
2. SHIP BARNACLES.]
PLATE XXX
SHIP BARNACLES (2)
These creatures are first-cousins, so to speak, of the acorn shells,
and they are called “Ship Barnacles” because they are so very fond of
fastening themselves to the bottoms of ships. Even after two or three
months, indeed, the hull of a vessel is often quite covered with them
below the water-line, and they check her speed so greatly that she has
to be taken into dock to have them scraped off before she can set out
upon another voyage.
You may generally find quite a number of these barnacles on the pieces
of timber which are so often flung up by the waves after a storm. And
you will notice that each of them grows, as it were, upon a kind of
stalk, instead of being fastened down to the surface of the wood, as
the acorn shells are upon the rocks. This stalk consists of the pillar
of cement with which the little animal covered its feelers just before
it changed its form for the last time.
There are a good many other kinds of barnacles, some of which are
found in very odd places. There is one, indeed, which always lives on
the backs of whales, and somehow manages to sink itself quite deeply
into their skins!
CHAPTER VI
THE SEA WORMS
PLATE XXXI
THE SEA MOUSE (1)
If you go down among the rocks when the tide is out, and hunt in the
muddy pools near low-water mark, you will be almost sure to find a very
odd-looking creature indeed. It is generally between three or four
inches long, and although it is called a “Sea Mouse” it looks very much
more like a hairy slug; for its whole body is covered with a matted
coat of bristles. But it is really a kind of sea worm. And it looks
just about as dull and dingy as any creature can possibly be.
Yet in reality it is one of the most beautiful animals which are found
in the sea, and if you want to see its beauty, all that you have to do
is to wash it. For the bristly coat which covers its body is a kind
of filter, which strains out the mud from the water which passes to
the gills; and it soon becomes so choked with mud that you cannot see
what the animal is really like at all. All that it wants, however, is
a really good bath: so just take it to a pool of clear sea-water, and
rinse it thoroughly. Then take it to another pool, and rinse it again.
Then take it to a third pool, and rinse it again; and go on rinsing it
till every atom of mud has been washed out of its hairy coating. And
then, if you look at it in the bright sunshine, I am quite sure that
you will be astonished to find what a lovely creature it really is. For
all the colours of the rainbow, and ever so many more besides, seem
to be chasing one another over its bristles, and altering with every
movement and every change of light. Doesn’t it seem strange that an
animal so beautiful as this should live with all its beauty covered up,
so that hardly any eye can ever see it?
But these bristles have another use besides that of a filter. Each of
them is really a kind of long, slender spear with a barbed tip, which
can be used as a weapon of defence. If you were to look at one of these
bristly spears through a good strong microscope you would see that it
was edged on both sides with sharp little hooked teeth, looking very
much like those of a shark. But you need not be in the least afraid
to handle a sea mouse, for although these slender spears look so
formidable, they are not nearly strong enough to pierce your skin.
[Illustration: PLATE XXXI
1. THE SEA MOUSE.
2. THE SABELLA.]
PLATE XXXI
THE SABELLA (2)
A good many different kinds of worms live on the sea-shore, and one of
the most curious of these is the Sabella. For it lives in long, narrow
tubes made of tiny grains of sand, which it sticks together with a kind
of natural glue. You may find these tubes in great numbers just about
low-water mark, and hundreds and hundreds of them are often twisted up
together in great masses, which are sometimes several feet in diameter.
The worms can travel up and down these tubes by means of tufts of stiff
little bristles on each side of their bodies; and sometimes they will
leave them altogether, crawl about on the sand for a little while, and
then make new ones. And if you keep them alive in a glass vessel filled
with sea-water, with a little sand at the bottom, you can watch them
building their wonderful tubes, carefully choosing grains of sand of
just the proper size, arranging them in position just as a bricklayer
lays bricks, and then sticking them firmly together.
PLATE XXXII
THE SERPULA (1 and 2)
If you look down into the pools among the rocks when the tide is out
you may often see a number of long, twisted tubes fastened to the
surface of the stones at the bottom. These are the dwellings of a very
curious sea-shore worm called the Serpula, and if you lift one of the
stones out of the water, and look down into the tubes, you will nearly
always see a bright scarlet object lying just beneath the entrance. And
then you may be quite sure that the animal is alive.
Now suppose that you carry the stone home with you, just as it is,
and put it into a vessel of sea-water. After an hour or two you will
find that the little scarlet objects have been poked out of the tubes,
and that they are really tiny stoppers, just like little corks, which
exactly fit the entrance when they are pulled inside. And you will also
find that a plume of feathery objects, which are also bright scarlet in
colour, is projecting out of the mouth of each tube. These red plumes
are the gills of the worms, and they will often remain spread for hours
at a time. But if you startle the animals--if your shadow falls upon
them, for instance--they will draw themselves down into their tubes in
about half a quarter of a second, and every tube will be corked up
by its tiny stopper, just as before.
[Illustration: PLATE XXXII
1. THE SERPULA.
2. SERPULAS IN TUBES.]
On the sides of its body the serpula has tufts of little bristly hairs,
just as the sabella has, which allow it to move up and down its tube.
But in order to enable it to draw itself back as quickly as possible
in moments of danger, it has a row of little hooked teeth on its back,
by means of which it can take a firm hold of the lining of its burrow.
I think you will be rather surprised when I tell you how many of these
teeth there are in the row. Just fancy! Each serpula has between
thirteen and fourteen thousand!
If you look at the oysters in a fishmonger’s shop, you may often see
the tubes of these curious worms fastened to the surface of the shells.
PLATE XXXIII
THE TEREBELLA (1)
This is another of the worms which live in tubes. You can generally
find its wonderful little dwellings by hunting in the small puddles of
sea-water which are left on the sands when the tide goes out. And you
can always tell them from those of the sabella and the serpula by the
curious little fringe round the entrance, which is made of the tiniest
grains of sand fastened together into slender threads. The tube itself
is made of larger grains, and is so tough and leathery that you can
give it quite a hard pull without breaking it. But as it is at least a
foot long, and is nearly always carried down underneath rocks or big
stones, you will not find it at all easy to dig it up. And the moment
that you alarm the little animal inside it always makes its way right
down to the very bottom of its tube.
Sometimes a terebella will leave its tube and go for a little swim in
the pool, wriggling its way through the water by first doubling its
body up and then stretching it out, over and over again. But it very
soon gets tired with its exertions, and sinks down to the bottom of the
pool to rest. Then, after awhile, it will set busily to work, and make
a new tube to live in instead of the old one.
There is another kind of terebella, called the Shell-binder, which
makes its tube of little bits of broken shell instead of grains of
sand. You may find the ends of these tubes sticking up out of the sand
about half-way between high and low-water mark. But they run down so
deeply that you will have to dig very hard indeed if you want to get
them out of the ground.
[Illustration: PLATE XXXIII
1. THE TEREBELLA.
2. THE LUG WORM.]
PLATE XXXIII
THE LUG WORM (2)
On any muddy stretch of beach, when the tide is out, you may see
numbers and numbers of little twisted casts, just like those which you
may find on the lawn in the garden on any warm damp morning. These are
made by Lug Worms, or “logs,” as the fishermen generally call them, and
they really consist of sand which the worm has swallowed during the
last three or four hours. For lug worms burrow by swallowing mouthful
after mouthful of sand, until they can swallow no more. They eat their
way down into the sand, in fact, just as earth-worms eat their way down
into the ground. And when their bodies are quite filled with sand, they
come up to the entrances of their burrows and pour it out in the little
twisty coils which everybody who has walked on the shore knows so well
by sight.
If you take a spade and dig down into the muddy sand you can find these
worms in great numbers. They are just about as big as earth-worms, and
are of all sorts of colours, some being brown, and some dark green, and
some purple, and some crimson. But on each side of the body they always
have thirteen pairs of bright scarlet tufts. These are the little gills
by means of which they breathe, and if you put them under a microscope
they look just like tiny bushes with brilliant red leaves.
You would think, perhaps, that when a lug worm bores its way through
the loose sand, the sides of its burrow would fall in behind it as
fast as it passed along. But from the surface of its body it pours out
a thin, sticky liquid which binds the sand together, and forms a kind
of lining to the burrow, like the brickwork of a railway tunnel. The
burrow is generally about two feet deep, and the worm always lives in
it with its head downwards. The worm itself, when fully grown, is from
six to ten inches long.
PLATE XXXIV
THE NEMERTES (1)
This is quite one of the most curious creatures to be found on the
sea-shore. It hides under large stones at the bottom of the pools,
and looks rather like a tangled boot-lace. But it is really a kind
of leech-like worm, and the wonderful thing about it is that it can
stretch its body out to almost any length, just as if it were made of
elastic. It always does this in catching its prey, which it seizes by
means of its sucker-like mouth, which has a kind of beak inside it.
Then it “plays” its victim just as an angler “plays” a fish, sometimes
stretching its body out to a length of fifteen or twenty feet, then
drawing it in again to a length of three or four, and so on over and
over again, until its prisoner is quite exhausted, when it proceeds to
devour it.
PLATE XXXIV
THE NEREIS (2)
The Nereis is a very common sea-side worm, and you can nearly always
find it by turning over the stones on the shore as the tide goes out.
It is brown in colour, with a dark red line along the back; and if you
look at it in the sunlight you will see flashes of bright blue playing
over the surface of its skin. And underneath it is of the most delicate
pink, with a glossy look which reminds one of mother-of-pearl. It is
one of the largest of all the worms, for it often grows to a length of
nearly two feet.
If you examine the back of a nereis, you will find a row of little
tufted organs running right along it. Each of these really consists of
two little flaps, which are folded together as long as the worm remains
still. But as soon as it begins to swim they open out and wave up and
down in the water; for they are really tiny paddles, by means of which
the nereis rows itself along. Altogether there are about four hundred
pairs of these little flaps, which move in perfect time together,
just like the oars of a well-rowed boat. Perhaps you may have seen a
boat-race, and you noticed, no doubt, how all the eight oars rose and
fell exactly at the same instant, as regularly as if they were moved by
machinery. Well, imagine a very long boat indeed rowed by four hundred
little rowers instead of only by eight, and each with two oars instead
of one, and then you will have some idea of what a nereis looks like as
it goes swimming through the water.
This curious worm does not live only under stones, for it is sometimes
found hiding in the whelk shells which are occupied by hermit crabs,
the worm and the crab living in the same shell together, and never
seeming to interfere with one another.
[Illustration: PLATE XXXIV
1. THE NEMERTES.
2. THE NEREIS.]
CHAPTER VII
STARFISHES
STARFISHES’ LEGS
Of course you know starfishes very well indeed by sight, for they are
flung up in numbers on the beach by almost every tide. But I wonder if
you know where their legs are!
Perhaps you did not know that they have any legs. But they have
hundreds and hundreds of them. Only, instead of keeping their legs
outside their bodies, as we keep ours, starfishes always keep them
inside, and poke them out through little holes in the skin when they
are required for use.
If you want to see the legs of a starfish, you can very easily do so.
First of all, you must catch a starfish, and make quite sure that he is
alive. You can easily find out that by picking him up. If his rays are
quite limp and flabby, and hang downwards from the disc, or middle part
of his body, so that they look rather like the legs of a table, he is
dead, and you can throw him away. But if they stand out stiffly he is
alive. Then just put him into a pool of sea-water, and wait. After a
few minutes you are almost sure to see that he is moving. Very slowly
he begins to glide along the bottom of the pool. If he comes to a
stone, he glides over it. If he comes to a rock, he glides up it. Then,
if you suddenly snatch him out of the water, and turn him upside down,
you will see his legs--little white fleshy objects waving about all
over the lower surface of his body. And if you look at them through a
good strong magnifying-glass, you will see that each one has a kind of
little cup at the end of a slender stem.
Now this cup is really a sucker, very much like the suckers of a
cuttle, only of course a great deal smaller. And the starfish walks by
pushing one or two of its rays forward, taking hold of the ground with
the suckers underneath them, and then pulling up the hinder rays and
taking hold with the suckers underneath those, and so on over and over
again.
PLATE XXXV
THE FIVE-FINGER STARFISH (1)
This is by far the commonest of all the starfishes. You can seldom
walk for even a short distance along the shore without seeing it. And
no doubt you might think that it must be a very harmless creature
indeed, for it does not look as if it could injure any other animal
in any way at all. Yet it is really a creature of prey, and feeds
upon shell-bearing molluscs, such as small bivalves, which it always
swallows whole. Then, when it has digested their bodies, it returns
their empty shells through its mouth. And it can even eat such big
creatures as mussels and oysters. Indeed, starfishes are the very worst
enemies of the oyster-beds, and in one fishery alone, on the coast of
North America, they are said to destroy more than ten thousand pounds’
worth of oysters every year!
[Illustration: PLATE XXXV
1. THE FIVE-FINGERED STARFISH.
2. THE BIRD’S-FOOT STARFISH.]
A very strange fact about the starfish is that if one of its rays is
cut off, a new one very soon grows in its place. Stranger still, if one
of these creatures is cut in two, each half begins to throw out new
rays, and in a few weeks’ time there are two starfishes instead of only
one! That seems impossible; doesn’t it? But yet it is perfectly true.
And another very curious fact about starfishes is that they keep their
eyes in very odd places--at the very tips of the rays. And in some
starfishes these eyes are furnished with lids, which can be opened and
shut!
PLATE XXXV
THE BIRD’S-FOOT STARFISH (2)
This is a very curious starfish, and a very handsome one as well. It
is curious, because its five rays are all joined together by membrane,
very much like the toes on a duck’s foot. That is why it is called the
“bird’s-foot” starfish. And it is handsome, because it has a scarlet
centre, a scarlet line all round the margin, and another one down the
inner margin of each ray, all the rest of the body being bright orange.
The bird’s-foot starfish is not very often seen, for it lives some
little way below low-water mark. But sometimes, when there has been a
violent storm at a season of spring-tide--and you will remember that
spring-tides come whenever there is a new moon or a full moon--it is
flung upon the beach by the retreating waves, and you may find it lying
on the sand when the tide is out.
PLATE XXXVI
THE SUN STARFISH
Sometimes you may find a very much larger and handsomer starfish lying
upon the shore. It has twelve rays instead of five, and is often as
much as eight or ten inches across. In fact, it looks very much like a
big sunflower. Generally it is bright scarlet in colour, but just now
and then one finds a sun starfish with a violet tinge; and sometimes,
while the middle part of the body is vermilion red, the rays are pale
rose-colour, or even pink.
[Illustration: PLATE XXXVI
THE SUN STARFISH.]
Like most of the starfishes, this animal has a very curious way of
protecting its eggs for some little time after they are laid. It heaps
them all up together into a pile, and then bends its rays downwards in
such a way that it stands upon their tips, looking just like a little
table with twelve very stout legs! It turns itself into a sort of cage,
in fact, with the eggs inside it, and so guards them carefully until
they hatch.
PLATE XXXVII
THE BRITTLE STARFISH
The Brittle Starfish is certainly the very oddest of all odd creatures,
for it not only grows new rays if the old ones should be torn off, but
actually breaks itself into pieces if it is startled or alarmed! And it
is such a timid animal that a slight touch, or even a shadow suddenly
falling upon it, will alarm it! Then it gives a kind of shudder, and
shatters itself into little bits, nothing being left but the central
disc and a heap of fragments! However, it does not appear to suffer
any pain, or to lose any blood, and the five wounds on the disc very
quickly heal. Then after a few days five little buds begin to show
themselves, which quickly grow into new rays, and in a few weeks’ time
the brittle starfish is as perfect as ever!
So ready are these creatures to break themselves up, that it is most
difficult to obtain a perfect brittle starfish for a museum.
Brittle starfishes are very active animals, and when they are alive
their long slender rays are always wriggling and coiling and twisting
about, hardly ever seeming to be still for a single moment. Indeed, one
naturalist compares a brittle starfish to five very long and active
centipedes stitched to a tiny pin-cushion!
There are several different kinds of these very curious animals, most
of which live at some little distance below low-water mark, and are
hardly ever caught except by means of the dredge. But sometimes you may
find one of them lying on the sand at the bottom of a pool among the
rocks.
[Illustration: PLATE XXXVII
THE BRITTLE STARFISH.]
PLATE XXXVIII
THE SEA URCHIN (1 and 2)
The “urchin,” as of course you know, is a common country name for the
hedgehog; and the Sea Urchin is so called because it is covered all
over with long spikes, just as a hedgehog is. These spines, however,
are very easily broken off, and when the animal dies, and its empty
shell is tossed to and fro by the waves, they are knocked off in a very
short time; so that when you meet with a sea urchin’s shell lying upon
the shore you nearly always find that it is covered with nothing more
than hundreds of very tiny pimples.
Now it is upon these little pimples that the spines grow. If you were
to examine one of the spines with a magnifying-glass you would find
that its base was hollow. This hollow base is just large enough to fit
over one of the pimples, to which it is fastened by a strong but rather
elastic muscle. So a sea urchin is able to move its spines about quite
freely. Indeed, it sometimes walks with them as well as with the little
sucker-feet, which it pokes out through tiny holes in the shell just as
a starfish does, moving a few forward at a time, and so hitching its
way along over the sand at the bottom of the sea.
If you succeed in finding a live sea urchin--and you can generally do
so without very much trouble, by hunting in the pools among the rocks
when the tide is out--you will notice that it has a very big mouth,
with five perfectly enormous teeth. They are so huge, indeed, that if
you had teeth as big, in proportion to your size, they would be about
as large as good big carving-knives!
On some parts of the coast sea urchins are eaten as food, being scooped
out of their shells with a spoon, just as we eat a boiled egg at
breakfast. For this reason they are sometimes known as “sea eggs,” and
those who have tried them say that they are very good indeed.
You would hardly think, perhaps, that a sea urchin and a starfish could
be related to one another, for they do not look in the least alike.
But if you take an urchin which has lost its spines, and examine it
carefully, you will see that it is really a kind of rolled-up starfish,
and you will be able to count its five rays quite easily.
[Illustration: PLATE XXXVIII
1. THE SEA URCHIN WITHOUT SPINES.
2. THE SEA URCHIN WITH SPINES.]
There is just one more thing that I must tell you about these very
curious creatures, and that is that they are very fond of covering
themselves all over with small stones, and little bits of broken shell,
and tiny pieces of sea-weed, in order that they may not be noticed.
They do this in a very odd way. I told you that they have numbers
of little sucker-feet, which they poke out through tiny holes in their
shells when they are required for use, just as the starfishes do.
Well, when they want to disguise themselves, they just push out two or
three hundred of these slender sucker-feet between their spines, and
take firm hold with them of any small objects that may be lying within
reach. In this manner they soon succeed in covering themselves all
over, and you might easily look at one of them as it lay at the bottom
of a rock-pool without recognising it at all.
CHAPTER VIII
SEA CUCUMBERS AND JELLYFISHES
PLATE XXXIX
THE SEA CUCUMBER (1)
If you grope about in the dark nooks and corners of a rock-pool, quite
close down to the water’s edge, when the tide is out, you may perhaps
find a curious little creature which looks rather like a greyish-white
cucumber, with an odd feathery tuft at one end of its body. This is
a Sea Cucumber, or Sea Gherkin, and is chiefly remarkable because it
seems to suffer very much at times from eating something which does
not agree with it. Then it cures itself in a very odd way indeed. It
gets rid of almost all the inside of its body, reducing itself to very
little more than an empty bag of skin, with just a little tuft at one
end! It throws off its teeth, it throws off the lining of its throat,
it throws off all its digestive organs. You would think that it would
kill itself by doing this, wouldn’t you? But it does not. And before
very long new teeth, a new throat lining, and new digestive organs
grow in the place of the old ones, so that in a few weeks’ time the
animal is just as perfect as it was before!
[Illustration: PLATE XXXIX
1. SEA CUCUMBER.
2. THE COMMON JELLYFISH.]
It seems rather hard to believe that an animal can treat itself in such
a manner as this, and yet continue to live, doesn’t it? But remember
that “truth is stranger than fiction,” and that some of the strangest
animals of all are found among those which live in the sea.
PLATE XXXIX
JELLYFISHES (2)
Jellyfishes are among the very oddest creatures which are found in the
sea; for their bodies are made up almost entirely of sea-water! It is
quite true, of course, that if you cut them in two the water does not
run away. But then if you cut a cucumber in two the water does not run
away; and yet cucumbers are made almost entirely of water. And the
reason why it does not run away is just the same in each case. Both
in the cucumber and in the jellyfish the water is contained in a very
large number of very tiny cells; and if you cut either of them across
you only divide a very small number of the cells, so that only a very
small quantity of water escapes. But if you leave a jellyfish lying on
the beach in the hot sunshine, and come back to look for it two or
three hours later, you will not find it. All that you will find will be
a ring-shaped mark in the sand, showing where the jellyfish had been
lying, with just a few threads of animal matter in the middle. All the
rest will have evaporated, because it was nothing else but water.
All the same, jellyfishes are very wonderfully made; and perhaps the
most wonderful thing of all about them is the fringe of long, slender
threads which hangs down from the edges of their bodies. For these are
the fishing-lines by means of which they catch their prey. Jellyfishes
feed on all sorts of tiny creatures--the fry of fishes, and the zoeas
of shrimps and prawns, for instance--and if you were to see one of
these swim up against those terrible threads, you would notice that it
at once became paralysed, and that in a very few moments it would be
dead. The fact is that all the way along these threads are set with
hundreds and hundreds of tiny oval cells, each of which has a very
slender dart, with a barbed tip, coiled up like a watch-spring inside
it. And the cells are made in such a way that as soon as they are
touched they fly open, and the little darts leap out. So, you see, if
any small creature swims up against the threads numbers of darts at
once bury themselves in its body. And, as these darts are poisoned, it
dies in a very short time.
Jellyfishes can swim through the water by spreading and contracting
their umbrella-shaped bodies, and you may sometimes see them travelling
about in such enormous numbers that the water is perfectly thick with
them.
PLATE XL
THE STINGING JELLYFISH (1)
Sometimes, after a strong south-westerly wind has been blowing for a
day or two in the early part of the autumn, you may find a brownish
yellow jellyfish lying upon the shore. It has a circular body about
as big as a soup-plate, fringed all the way round with great masses
of long yellow hairs. And if you find one of these creatures you are
almost sure to find another before very long, and then another, and
then another; for they nearly always swim about in shoals together.
Now, if you do meet with one of these jellyfishes, be very careful
not to touch it with your bare hands. And if you should happen to be
bathing, and to see one floating in the water near you, just get out
of its way as fast as you possibly can. For those long yellow threads
which hang down from the margin of its body sting just like nettles,
and the least touch from them will cause a great deal of pain. If you
have a thin skin, indeed, the sting of this terrible jellyfish may make
you very seriously ill, and several weeks may pass before the effects
of the poison pass away.
Yet the fishing-threads of this jellyfish are scarcely thicker than
hairs, and the little darts which do so much mischief are so slender
that you cannot see them at all without the help of a good strong
microscope. Doesn’t it seem strange that such tiny weapons can be so
dreadfully poisonous?
PLATE XL
THE SEA ACORN (2)
This is a very common jellyfish indeed; yet hardly anybody ever sees
it. That is because it is very small and very transparent, so that as
it swims about in the water it is almost invisible. And if it is flung
up on the beach it dries up in a very few minutes. But if you want to
look at it, you can very easily do so. On a warm, still day, when the
sea is quite smooth, just dip a small net into the water, and work it
gently to and fro. Then lift it out and examine the sides carefully,
and you are almost sure to see three or four little lumps of jelly,
not much bigger than peas. These are sea acorns, and if you put
them into a glass vessel of perfectly clean sea-water, you will very
soon find that they are swimming about. For though you cannot see the
animals themselves, which are quite as transparent as the water, you
will notice little flashes of coloured light, sometimes blue, sometimes
green, sometimes yellow, and sometimes red, which just gleam out for
about half a quarter of a second, and then disappear. You might almost
think that a tiny rainbow had been dissolved in the water.
[Illustration: PLATE XL
1. THE STINGING JELLYFISH.
2. THE SEA ACORN.]
The fact is this. Running round the oval body of the sea acorn are
eight narrow bands, and on each of these are a number of very tiny
scales, placed one above another, which keep on rising and falling
again, like so many little trap-doors. These scales are really paddles,
by means of which the animal drives itself through the water, and as
they move up and down they catch the rays of light and break them up,
just like that triangular piece of glass which we call a “prism.” And
though you cannot see the jellyfish itself you can see these little
flashes of coloured light, and so can trace the course of the little
creature as it travels slowly along.
This curious jellyfish has only two fishing-threads, which hang down
from the lower part of its body. But from each of these a number of
little side-threads spring out, just like the “snoods” on the lines
which fishermen use in the sea. And the animal is always throwing these
out and drawing them in again, so that it really “fishes” for the tiny
little creatures on which it feeds.
CHAPTER IX
SEA ANEMONES
HOW SEA ANEMONES ARE FORMED
The most beautiful of all the creatures which live in the sea are
undoubtedly the Sea Anemones, which are just like living flowers of
all sorts of lovely colours. But I do not know why they are called
sea “anemones,” for they are much more like asters, or dahlias, or
chrysanthemums.
These anemones are made in a very curious way. You will notice, as
you look down into a rock-pool, that their soft fleshy arms, or
“tentacles,” are all spread out like the petals of a flower. If you
touch them, however, they at once come closing in and disappear, so
that in two or three moments the creatures look like mere lumps of
coloured jelly. But if you wait for a little while they will push out
their tentacles again, and spread them just as before.
The fact is that the body of a sea anemone is a kind of double bag.
Suppose you take a paper bag, twist up the mouth, and push it
downwards, so that the sides of the bag surround it all the way round.
You will then have two bags, as it were, one inside the other, the
space between the two being filled with air. Now that is just the way
in which the body of a sea anemone is formed, with this difference,
that the space between the outer bag and the inner one is filled with
water. It forms, in fact, a kind of water-jacket.
Next, remember that all those spreading tentacles are really tubes,
like the fingers of a glove, closed at the top, but opening at the
bottom into this water-jacket. And remember also that the outer walls
of the body are formed of very strong muscles. So, you see, when
the anemone wants to spread its tentacles, all that it has to do is
to contract these muscles. The water is then squeezed up into the
tube-like tentacles, which of course expand. When it wants to close
them it relaxes the pressure, and the water flows out of the tubes
again and back into the water-jacket, so that they all come folding in.
The lower part of an anemone’s body is called the “foot,” and is really
a big and strong sucker, by means of which the animal clings so firmly
to the surface of a rock or a stone that it almost seems to be growing
out of it. But these creatures do not spend the whole of their lives
without moving, as oysters and barnacles do. Sometimes they will creep
slowly along over the surface of the rock, in order to find a more
comfortable situation, or one where they will have a better chance of
catching prey. And sometimes they will loose their hold of the rock
altogether, rise to the surface of the water, turn upside down, and
hollow their bodies in such a way that they form little boats, which
can float along over the waves for quite a long distance.
PLATE XLI
THE SMOOTH ANEMONE (1)
This is by far the commonest of all the sea anemones, and you may find
it in hundreds and thousands by going down among the rocks when the
tide is out, and looking into the pools. You are almost sure to see
that their rocky walls are dotted all over with lumps of brown or dark
green jelly, some only about as big as peas and some as large as plums.
These are Smooth Anemones, with their fleshy feelers, or “tentacles”
closed. And just here and there you may see one of them open, and you
will notice that all the way round the edge of its body, between the
roots of the tentacles, it has a row of little bead-like objects of
the most beautiful turquoise blue. For this reason the smooth anemone
is sometimes known as the “beadlet.”
You can easily keep these anemones in captivity, for they are very
hardy, and are no trouble at all to feed. Indeed, they will go without
any food at all for three or four months together, and seem all the
better for their long fast. But if you put a tiny dead crab, or a
shrimp, or a sandhopper, into the midst of their spreading arms, you
will see the tentacles close round it, and push it down into the mouth,
which lies just in the very middle. For about forty-eight hours the
animal will then remain closed up. But as soon as it has digested its
dinner out will come the tentacles again, bringing with them the empty
shell of the victim.
Every now and then, like other anemones, this animal changes its skin,
and when it leaves its position on the side of a rock-pool and crawls
to a new one, it nearly always leaves a cast skin behind it.
[Illustration: PLATE XLI
1. THE SMOOTH ANEMONE.
2. THE DAISY ANEMONE.]
PLATE XLI
THE DAISY ANEMONE (2)
This is not nearly such a common creature as the smooth anemone,
but you may sometimes find it in the rock-pools at low-water on our
southern and western coasts. It is pale greyish yellow in colour,
and has an odd way of altering its shape from time to time, so that
sometimes its body is long and slender, and sometimes it is short and
stout, while the disc may be long and narrow one day, and almost round
the next. You can always tell it at once, if you should happen to meet
with it, by looking at its fleshy feelers, or tentacles, which are
marked with rings of grey and white.
PLATE XLII
THE THICK-ARMED ANEMONE (1)
Where the coast is sandy and rocky too this anemone is often rather
common. Yet very few people ever see it, because it nearly always
fastens itself quite low down on the rocks which border the pools, so
that at least half of its body soon becomes covered up with sand.
Besides this, it has a great number of very tiny sucker-feet, not
unlike those of the starfishes and the sea urchins, and with these
it clings to tiny stones and bits of broken shell, which often quite
conceal its upper surface, so that one really cannot see the anemone
itself at all. But it is quite one of the very handsomest of all the
British sea anemones, for when it is fully grown it is over five inches
in width; and sometimes it is pearly white in colour, and sometimes it
is green, and sometimes it is purple and brown, and sometimes it is
crimson, while its tentacles are banded with scarlet and white. These
tentacles are rather stout in proportion to their length, and when they
are fully spread the animal looks very much like a cactus dahlia.
PLATE XLII
THE SNAKE-LOCKED ANEMONE (2)
This is also one of the prettiest of these very pretty creatures. But
it is not in the least like the thick-armed anemone, for instead of
having a broad, stout body it has a long slender one; and instead of
short, thick tentacles, like the petals of a dahlia, it has a bunch of
almost thread-like arms, which really rather remind one of little
white snakes. And when they are spread these long arms are hardly ever
still, but are always waving about in the water.
[Illustration: PLATE XLII
1. THE THICK-ARMED ANEMONE.
2. THE SNAKE-LOCKED ANEMONE.]
When the snake-locked anemone closes up, however, you would never know
it for the same creature, for it not only draws its long tentacles back
into its body and tucks them away out of sight, but contracts the body
itself until it is almost flat. Unless you looked very carefully at the
rock to which it was clinging you would never notice it at all.
This anemone is not a very common one, and is chiefly found on the
rocky coasts of Devonshire and Cornwall. In colour it is almost white.
CHAPTER X
MADREPORES, CORALS, AND SPONGES
PLATE XLIII
MADREPORES (1)
In some ways these curious creatures are very much like sea anemones,
and if you were to find one with its tentacles spread you would be
almost sure to think that it was a small anemone. But if you touched
it you would find that you had made a mistake, for instead of closing
itself up into an almost shapeless lump of jelly, as the anemones do,
it would just draw back its tentacles, and leave a kind of flinty
skeleton still standing up. For madrepores are really much more like
the wonderful little creatures which make coral. They suck lime,
in some strange manner which nobody quite understands, out of the
sea-water, and build it up round and underneath their own bodies. And
if you startle them in any way they draw themselves down inside this
shelly covering, and disappear from sight altogether; so that all that
you can see is a number of thin plates standing upright on their
edges, and looking rather like the lower surface of a mushroom turned
into stone.
Madrepores feed on very tiny animals, such as the fry of small fishes,
and the zoeas of shrimps and prawns. And they catch their victims by
means of a number of fleshy tentacles, which are very much like those
of the sea anemones, except that they always have little round knobs at
the tips. These tentacles are set with numbers of tiny cells containing
slender poisoned darts, just as those of the anemones are.
If you want to find madrepores, you must look for them among the rocks
near the water’s edge when the tide is at its lowest. But they are not
very common, and on many parts of the coast they are never found at all.
PLATE XLIII
THE SEA FINGER (2)
If you walk along the shore as the tide goes out, you may often find a
soft, pink, fleshy object which has been thrown up by the waves. And
if you search among the pools at low-water, you are nearly sure to see
other soft, pink, fleshy objects just like it growing upon their rocky
sides, or upon the stones and shells which lie at the bottom. They are
often known as “dead men’s fingers,” or “dead men’s toes.” But as
those are not very nice names, we will call these objects “sea fingers.”
Now if you pick up one of these sea fingers and look at it carefully,
you will see that its surface is pierced all over with numbers of tiny
holes. And if you take a good strong magnifying-glass, and look at one
of the holes through that, you will see that it is shaped like a little
flower with eight petals, or a star with eight rays.
The fact is that the sea finger is the home of a most curious animal;
or perhaps one should rather say that it is the home of hundreds of
most curious animals. Indeed, it is not at all easy to know which is
the right way to describe it. For if you were to take a living sea
finger, and to put it into a vessel of clear sea-water, you would very
soon notice that a little tiny star-shaped animal had poked itself
out of each little star-shaped hole. There would be hundreds of these
little animals--or “polyps,” as they are called--altogether. But
yet they would only have one body between them, for they are joined
together in such a wonderful way that the food which is caught and
eaten by one polyp nourishes all the others as well as itself!
[Illustration: PLATE XLIII
1. THE MADREPORE.
2. THE SEA FINGER.]
PLATE XLIV
THE TUFT CORAL (1)
Nearly all the coral-building animals are found in the tropical seas,
for they can only live in water which is quite warm all the year round.
But there are just a very few which are sometimes found off our own
shores, and one of these is the Tuft Coral. It looks rather like a tree
which has just been “pollarded” by having all the small branches taken
away and all the big ones cut quite short; and sometimes it weighs as
much as six or even seven pounds.
People sometimes say that the curious substance which we call “coral”
is made by “coral insects.” But the little animals which make it are
not related in any way to the true insects. They are really tiny
polyps, very much like those of the sea finger; and they suck up lime
out of the water, and build it up underneath and round their own
bodies, just as the madrepores do.
If you were to place one of these tuft corals in a vessel of clear
sea-water, and to watch it carefully, you would soon see the little
polyps poking themselves out, and spreading their tiny fleshy feelers,
or “tentacles.” The coral which they make is pearly white in colour,
with just a faint tinge of rosy red, and the polyps themselves are
partly white, and partly fawn, and partly chestnut brown.
One does not often find a tuft coral, however, for the polyps like to
live in rather deep water. But when there is a very high spring-tide,
as there generally is about the end of March and the end of September,
the waves retreat afterwards a good deal farther than usual. And then,
if you go right down to the water’s edge, you may perhaps find a tuft
coral fastened to the rocks.
PLATE XLIV
THE BREAD-CRUMB SPONGE (2)
I dare say that you will be rather surprised to hear that nearly three
hundred different kinds of sponges have been found in the British seas.
You will not be able to find very many of these, however, for they
nearly all live in deep water, and have to be scooped up by means of
the dredge. But the Bread-crumb Sponge is easily found, for it lives in
shallow water, and you are nearly sure to find it if you look for it in
the rock-pools.
[Illustration: PLATE XLIV
1. THE TUFT CORAL.
2. THE BREAD-CRUMB SPONGE.
3. THE GRANTIA SPONGE.
4. FORAMINIFERA.]
But I hardly think that anybody, on seeing it for the first time, would
take it to be a sponge at all. For it is not in the least like a bath
sponge. It is just a kind of fleshy crust, sometimes greenish in
colour and sometimes yellow, which grows round the stems of sea-weed,
or covers the surfaces of rocks and stones. And the odd thing about
it is that when it clings to sea-weeds its surface is quite smooth,
with a number of large holes in it, but that when it grows on rocks it
is covered all over with little projections which look just like the
craters of volcanoes.
It is rather difficult to describe the animal which lives in the
sponge, for it really consists of a large number of tiny animals all
joined together in one common mass, very much like the polyps of the
sea finger. But they are so very small that unless you examine them
by means of a good strong microscope they only look like a mass of
brownish jelly.
These little creatures obtain their food in a very curious way. If you
look at the surface of the sponge through a magnifying-glass, you will
see that it is pierced by a great many very tiny holes as well as by a
number of bigger ones. Now water is always passing in through the small
holes and out again through the big ones; and as it does so the little
creatures manage to suck out all the tiny atoms of animal and vegetable
matter which were floating about in it.
PLATE XLIV
THE GRANTIA SPONGE (3)
This is quite a small sponge, which you may often find by hunting about
in the rock-pools just above low-water mark. Sometimes it clings to
sea-weeds, and sometimes it hangs down from the surfaces of the rocks;
and when you find one you are almost sure to find several others close
by.
In appearance, they are rather like little flat white bags, or purses;
and when they reach their full size they are generally about an inch
long and an inch and a half wide.
PLATE XLIV
FORAMINIFERA (4)
“Foraminifera!” That is rather a long name; isn’t it? But if we cut it
in two, and strike out one of the letters, we shall see what it means.
_Foramin-(i)-fera_. Now the first part of the name is a Latin word
which means “a hole,” and the last part is another Latin word which
signifies “bearers.” So “foraminifera” means “hole-bearers,” and this
title has been given to certain very tiny creatures which live in the
sea because they inhabit shells, which are pierced all over by numbers
and numbers of still tinier holes.
These foraminifera are so very small that numbers of them can live in a
single drop of water! Yet, strange to say, all the chalk in the world
is made of their shells! For in days of old--thousands and thousands
of years ago--they were found in the sea in millions of millions of
millions. And as they died their empty shells sank down to the bottom
of the sea in such enormous numbers that at last they formed a layer
hundreds of feet thick. Then suddenly one day there came a great
earthquake, and a great deal of this vast layer of shells was forced up
above the surface in the form of what we now call chalk. So that “the
chalk cliffs of old England” are really made of nothing but shells, so
very small indeed that you cannot see them without the help of a very
strong microscope!
There are a great many different kinds of foraminifera. But if you look
at them through a good microscope you will always see that their shells
are pierced by the tiny holes from which they take their name.
CHAPTER XI
SEA-WEEDS
PLATE XLV
THE BLADDER-WRACK (1)
I dare say that you would like to know something about the sea-weeds
which you may find on the shore; so I am now going to describe some of
those which you are almost certain to meet with.
First of all, then, and commonest of all, there is the bladder-wrack.
Wherever there are rocks on which it can grow you will always see it in
great masses. And after every storm enormous quantities of it are torn
off and flung upon the beach. Then the farmers send down their carts to
carry it away. For after it has been piled up in heaps for some time,
so as to allow it partly to decay, it makes a most useful manure; and
the farmers are only too glad to be able to spread it over their fields.
This plant is called the “bladder-wrack” because of the odd little
oval bladders filled with air which are found in the leaves, and which
explode with a slight report if you tread upon them or squeeze them.
[Illustration: PLATE XLV
1. THE BLADDER-WRACK.
2. THE OAR WEED.]
PLATE XLV
THE OAR WEED (2)
This is a very fine sea-weed indeed, for it often grows to a height
of ten or eleven feet. But you are not likely to see it growing, for
it lives in rather deep water, where it is always covered even at the
lowest tides. It is often flung up by the waves, however, and you must
many times have noticed its long, thick stem and flat plate-like leaves
lying upon the shore as the tide was going down.
The stem of the oar weed is often used for making the handles of
knives. When it is quite fresh, it is so soft that the “tang” of a
knife-blade--the part, that is, which is fastened into the handle--can
be forced into it quite easily. But if it is put aside for a few months
to dry it becomes as hard and solid as horn, and holds the blade so
firmly that it is almost impossible to pull it out again.
If you look at the “roots” of the oar weed you will see that they are
not like those of plants which grow in the ground, but are really
very strong suckers. For sea-weeds do not send their roots down into
the rock, as land plants do into the ground, but merely cling to the
surface. That is why they are so easily torn up by the waves.
PLATE XLVI
CORALLINE (1)
For a great many years naturalists could not make up their minds
whether this very pretty sea-weed was really a sea-weed or not. For
it possesses the curious power of sucking out lime from the sea-water
and building it up round itself, just as the polyps of the madrepores
and the corals do: so that when it dies and decays it leaves a kind of
chalky skeleton behind it. For this reason it was often supposed to be
really a kind of coral. We know now, however, that it is a plant. For
if it is placed in acid, which dissolves away this “skeleton,” we find
that a true vegetable framework is left behind it.
While it is alive the coralline is of a deep purple colour. It is quite
a small plant, growing only to a height of four or five inches, and you
may find it in quantities on the rocks near low-water mark.
PLATE XLVI
DULSE (2)
This weed is also known as the Dillisk, or Dillosk. I dare say that you
have often seen it, for it is quite common on nearly all the rocky
parts of our coasts, sometimes growing on the rocks themselves, and
sometimes on the larger sea-weeds. In colour, it is a deep, dark red,
and if you look down upon it on a bright sunny day, as it grows in
a pool of clear sea-water, you may see all kinds of lovely rainbow
tints playing over its leaves. The leaves or “fronds” as they are more
properly called, are about two inches long and a quarter of an inch
wide.
[Illustration: PLATE XLVI
1. CORALLINE.
2. DULSE.]
The dulse is one of the sea-weeds which are used for food. On many
parts of the coast of Ireland it is very largely eaten, both boiled and
raw, and some people are so fond of it that they have it for breakfast
every day.
PLATE XLVII
THE GREEN LAVER (1)
Another name for this plant is the Sea Lettuce; and certainly, with
its broad, bright green, crinkled leaves, it does look rather like a
cabbage lettuce. It is a very useful plant to keep in a salt-water
aquarium, for its leaves give off little bubbles of oxygen gas, which
help to keep the water pure and fit for fishes and other creatures to
live in. If you look at it on a bright sunny day you will often find
that the leaves are covered all over with these tiny bubbles, which
look just like little drops of quicksilver.
The green laver is found in abundance on most of our rocky coasts, and
is often boiled down into a kind of jelly and used as food.
PLATE XLVII
THE PURPLE LAVER (2)
This plant is very much like the green laver, except that it is purple
in colour instead of green. It is often boiled down into jelly and used
as food, more especially in Ireland, where it is generally known as
“sloke,” and is cooked and brought to table in a silver saucepan.
PLATE XLVIII
CARRAGEEN MOSS (1)
I do not know why this plant should be called a moss, for it is not in
the least like the true mosses, as you can easily see by looking at the
illustration. It is very common indeed, growing both in the pools among
the rocks and also in deep water. But it is not a very easy plant to
describe, for it varies very much in colour, being sometimes green,
and sometimes yellow, and sometimes purple. Like the dulse, it is often
used for food, being boiled down into a kind of jelly, and then either
eaten by itself, or mixed with tea or coffee. It makes very good size,
too, and is used a good deal in the manufacture of calico. Farmers use
it, too, for fattening calves, and also for mixing with the potatoes
or meal with which the pigs are fed. So that altogether it is a very
useful sea-weed indeed.
[Illustration: PLATE XLVII
1. THE GREEN LAVER.
2. THE PURPLE LAVER.]
PLATE XLVIII
THE SEA GRASS (2)
This is a very pretty sea-weed, which you may often find growing in
great quantities in the pools which are left among the rocks as the
tide goes down. When its long, narrow fronds are waving to and fro in
the water it really looks most lovely, and you can almost fancy that
you are gazing down into fairyland. And as the shrimps and prawns and
little fishes dart in and out among its bright green leaves, one might
almost imagine them to be the fairies!
The fronds of this pretty sea-weed vary a good deal in width, for
sometimes they are like strips of narrow ribbon, and sometimes they are
scarcely broader than hairs.
PLATE XLVIII
THE GRASS WRACK (3)
In one way this is the most curious of all the plants which you may
find on the shore. For it is not really a sea-weed at all, but is a
flowering plant which somehow or other has taken to living at the
bottom of the sea. You may often find it in the deeper pools just above
low-water mark; and you can tell it at once by its very long, very
narrow, bright green leaves. These leaves are often three or four feet
in length, while they are only about three-eighths of an inch wide; so
that really they do look very much like blades of grass.
The grass wrack is not one of the true grasses, however, for it has
real flowers, which grow in a kind of sheath formed by one of the
shorter leaves. And its stem creeps along under the muddy sand, and
throws up leaves at intervals, very much like that of the common
bracken. On many parts of the coast it grows in the greatest abundance.
There are large fields of it, so to speak, below low-water mark, which
afford refuge for all kinds of small sea-creatures. Indeed, if you want
to catch these animals for yourself, the very best way to do it is to
wait until the tide is quite low, and then to wade into the water
and fish about in the masses of grass wrack with a small net.
[Illustration: PLATE XLVIII
1. CARRAGEEN MOSS.
2. THE SEA GRASS.
3. THE GRASS WRACK.]
Great quantities of the long, narrow leaves of this plant are often
flung up on the shore; and when they have been thoroughly dried they
are often used for packing glass or china, instead of hay or straw.
Printed by BALLANTYNE, HANSON & CO.
Edinburgh & London
INDEX
Acorn shells, 90
Anemone, smooth, 123;
anemone, daisy, 125;
anemone, thick-armed, 125;
anemone, snake-locked, 126
Anemones, sea, 121
Bladder-wrack, 136
Carrageen moss, 140
Chiton, 34
Cockle, 39
Coralline, 138
Cowry, 33
Crab, edible, 64;
crab, shore, 65;
crab, masked, 67;
crab, fiddler, 68;
crab, thornback, 69;
crab, long-beaked spider, 71;
crab, four-horned spider, 72;
crab, pea, 73;
crab caterpillars, 74;
crab chrysalids, 76;
crab, hermit, 77
Crabs, 58-64
Cuttle, 16
Dog whelk, 20
Dragonet, 6
Dulse, 138
Egg of the dog-fish, 13
Egg of the skate, 12
Flounder, 9
Foraminifera, 134
Gaper, 46
Gobies, 1
Grass wrack, 142
Grey top, 32
Jellyfishes, 115
Laver, green, 139;
laver, purple, 140
Limpet, common, 27;
limpet, key-hole, 28;
limpet, smooth, 29;
limpet, cup and saucer, 30
Little piddock, 50
Lobster, 81
Lug worm, 101
Madrepores, 128
Mussel, 40;
mussel, horse, 42
Nemertes, 102
Nereis, 103
Oar weed, 137
Oyster, 36;
oyster, saddle, 38
Painted top, 31
Periwinkle, 23
Piddock, 47
Pinna, 56
Pipe-fish, 7
Plaice, 11
Prawn, 83;
prawn, æsop, 85
Purpura, 24
Razor, 53
Sabella, 97
Sabre razor, 55
Sandhopper, 87
Sand screw, 89
Scallop, variable, 43;
scallop, radiated, 44;
scallop, hunchback, 45
Sea acorn, 118
Sea cucumber, 114
Sea finger, 129
Sea grass, 141
Sea mouse, 95
Sea snail, 25
Sea urchin, 111
Serpula, 98
Ship barnacles, 93
Shipworm, 51
Shrimp, 86
Smooth blenny, 4
Sponge, bread-crumb, 132;
sponge, grantia, 134
Spotted gunnell, 5
Starfish, five-finger, 106;
starfish, bird’s-foot, 108;
starfish, sun, 108;
starfish, brittle, 109
Starfishes’ legs, 105
Stinging jellyfish, 117
Sting winkle, 21
Sunset shell, 45
Terebella, 99
Tuft coral, 131
Wentletrap, 26
Whelk, 19
Printed by BALLANTYNE, HANSON & CO.
Edinburgh & London
TRANSCRIBER’S NOTES:
Italicized text is surrounded by underscores: _italics_.
Obvious typographical errors have been corrected.
Inconsistencies in hyphenation have been standardized.
*** End of this LibraryBlog Digital Book "The Sea-Shore: Shown to the Children" ***
Copyright 2023 LibraryBlog. All rights reserved.