Jolin Swett
FIRST LESSON
NATURAL HISTORY.
BY
MRS. AGASSIZ.
SECOND EDITION.
BOSTON:
LITTLE, BROWN AND COMPANY.
LONDON:
SAMPSON LOW, SON AND COMPANY.
M DCCC LIX.
oH
Entered according to Act of Congress, in the year 1859, by
LITTLE, BROWN AND COMPANY,
In the Clerk's Office of the District Court of the District of Massachusetts
c-uUCATION DSP*.
RIVERSIDE, CAMBRIDGE:
PRINTED BY H. 0. HOUGHTON AND COMPAXIT.
PREFACE.
THIS little book, which it is hoped may
be interesting for children, and perhaps of
some use to parents whose children share
the general juvenile delight in Aquariums,
has been prepared under the direction of
Professor Agassiz, and owes any little merit
it may possess to his advice and assistance.
541764
CONTENTS,
SEA-ANEMONES AND CORALS 7
CORAL REEFS 28
HYDROIDS AND JELLY-FISHES 43
STAR-FISHES AND SEA-URCHINS 62
FIRST LESSON IN NATURAL HISTORY.
CHAPTER I.
SEA-ANEMONES AND CORALS.
MY DEAR LiSA AND CONNIE,
I was thinking the other day of the pleas-
ant times we passed together at the sea-shore
last summer, and remembering how often, in
the evening, when your playtime was over, and
we were sitting in the quiet twilight, waiting
for your bedtime, you used to beg for stories ;
and it occurred to me that, in the long and
snowy winter, I might prepare some stories for
next summer, and then, when you come after
tea, and say, " Now, Aunt Lizzie, tell us a
story," I shall have one all ready, and I need
not answer, as I often used to do, that my
brain was empty, and, hunt as I would, I
8 SEA-ANEMONES AND CORALS.
coulvl TKvt: find a story in any corner of it.
But vh&re : is'.ohe thing you may not like about
the stories I think of writing for you; I want
them to be true stories, and not about little
boys and girls, but about animals. Do you
recollect the nets I made for you last sum-
mer, and how you used to catch in them the
tiny little fishes that lived in the pool left by
the sea-waves in the hollow of that large rock
near our house? Now, thete are many other
animals living in the little pools left by the
tide on the beaches and between the rocks
and stones, which are both beautiful and cu-
rious, and which, if you knew a little more
about them, would interest you quite as
much as the little fishes you liked to see
swimming about in your Aquarium last sum-
mer.
Have you ever heard of a Sea- Anemone ?
Don't fancy, from its name, that it looks any-
thing like the pretty white or pink Anemones
that delight you so much in the woods in
spring, and yet they have been called so, be-
cause, though they are as much animals as
Berty's little dog Pinky, or your pussy-cat, they
SEA-ANEMONES AND CORALS. 9
yet have a look like a flower. But this is
only when it pleases them to spread out their
little bodies, and flaunt all their pretty fringes;
and, as you will see, when I tell you a little
more about it, they can shut themselves up,
and look as ugly and dull as they please. In
this you see, they differ very much from a
flower, which cannot fold up its leaves and
put them away when it likes. It is true that
some flowers close at night, and open in the
day, but it is not because they want to do so,
but because the state of the atmosphere causes
them to shut and open.
Some day next summer at Nahant, we will
go at low tide in search of a Sea- Anemone,
and, if we are fortunate, we shall find some-
where among the rocks near Sunken Ledge,
one of these ocean flowers. It will be rather
slippery on the wet sea-weed, but we shall not
mind one or two tumbles, if we find what we
are looking for. I dare say we shall meet with
one, hiding himself away in some little dark
corner of the rocks, (for they rather like the
shade,) with his fringes all drawn in, appear-
ing like a brown soft lump, and thinking that,
10 SEA-ANEMONES AND CORALS.
because he has made
himself look so ugly
and unattractive, no-
body will disturb him.
* Here we have a
No. i. drawing of him. But
we will not be deceived by his uninviting
looks. "We will take him up very softly, part-
ing him gently with our fingers from the rock,
for he is very tender, and adheres closely
to his resting-place, and when we have him
safely at the house we will put him in a
glass bowl with some sea-weed and a few
stones, that he may, if possible, believe him-
self to be still at home in his puddle. And
now we must watch him long and patiently,
if we would see how he changes himself into
his flower-like form. As he lies now, he is
like nothing but a ball of rather dark, soft
substance, flat on the side by which he was
attached to the rock. But watch him, slowly,
very slowly, for he has 'not the power of any
quick motion, he begins to expand, the little
* This and the three following wood-cuts represent the common
Sea- Anemone (Actinia marginata) of our coast.
SEA-ANEMONES AND COKALS.
11
soft ball rises gradually,
till it stands up, as
it does in the picture
you see here, from
its summit it puts out
long and graceful feel-
ers growing so close No g
that they look to you like fringes, forming
a sort of wreath around
the top. Very slowly and
softly these beautiful
fringes creep out from
the inside of the little
animal, where they have
lain, drawn in. and pack-
ed away so snugly that
you never suspected they were there, and then
when they are fully spread, they move gently
up and down, with a slow, waving motion.
My wood-cut gives you no idea of their
beauty ; you must imagine them light colored,
and soft and delicate as the down on a feather.
So pretty as they are, and so soft, you will hard-
ly believe that they have attached to them an
instrument which is as dangerous and deadly to
12 SEA-ANEMONES AND CORALS.
all the little animals which the Sea-Anemone
likes for its food, as the claws of your pussy are
to a mouse. Do you know what a lasso is ? It
is a long rope which, in some countries, is used
for catching cattle. It has a noose at one
end, and is carried, coiled up in the hand,
till the animal comes quite near, and then it
is thrown suddenly out, and the men who
use it understand how to cast it with such
dexterity and force, that the noose slips over
the animal's head or feet, and then they have
him fast enough. Now the Sea- Anemone
has upon these fringes or tentacles, as I will
call them, because that is their true name,
numbers of what are called lasso-cells. They
are so small that you cannot see them with
your naked eye, but each little cell contains a
long hollow thread coiled up in a spiral within
it. Now they have the power of flinging this
thread suddenly out, when there is any little
shrimp or shell swimming about in the water
which they fancy for a meal, and in an instant
he finds himself entangled in their tiny cords
like a fly in a spider's web. Little shrimps
swimming near them, full of activity, are sud-
SEA-ANEMONES AND C03ALS. 18
denly struck dead at the mere contact with
these poisonous whips, and may be seen hang-
ing lifeless on the feelers. Here is the figure of
a magnified lasso-cell, with the
coil partly turned out. It is a
sort of bag, as you see, within
which the thread is wound up in
a spiral, and from which it can
be thrown out in an instant at
the will of the animal. These
cells are so small, that only a
very powerful microscope will re-
veal them to the sight, for they
are no more to be discerned by
the naked eye than the separate
stars forming the Milky- Way
can be distinguished without the No. 4.
aid of the telescope. When the prey is caught
in this way, the tentacles close upon it and
pass it into the mouth; but in order that you
may understand this, I must tell you some-
thing about the mouth, and about the inside of
our little Sea- Anemone. If we look down upon
him from above, we shall see in the centre of
the fringes a hole, and that hole is the mouth
which opens into a kind of sac that hangs down
14
SEA-ANEMONES AND CORALS.
No 5
below it, inside the animal, and is its stomach,
into which all the
food passes and
where it is digest-
ed. If we could
make a cut across
our little friend, so
as to get a glimpse
of his internal
arrangement, we
should see this sac
which makes a
cavity in the middle of the body, and we
should find that the rest of the body is di-
vided by a number of partitions, running from
top to bottom, and radiating from this cen-
tral sac to the outside ; so that looked at from
above they run from the middle to the edge like
the spokes of a wheel, but they are continued
from the summit to the
base, thus dividing the
animal by many parti-
tions. Now, in order
that you may under-
stand how he digests
. 6 . his dinner, when he has
SEA- ANEMONES AND CORALS. 15
caught and killed it, you must know that the
sac or stomach in the middle of the body
opens by an aperture in the .bottom into the
main body. The sea-water, which enters free-
ly through the mouth with the food, softens
it, helps reduce it to a kind of pulp, and it
passes from the stomach into the body, circu-
lating through all the partitions and passing
from them into the tentacles; for every one of
the tentacles connects with one of the spaces
divided off by the partitions. Thus you see
the whole body is nourished by whatever en-
ters at the mouth. On the inner side of the
partitions, little eggs are formed, which hang
there till they are ready to be hatched, and
then they pass out through the mouth, into the
water, where they grow into Sea-Anemones
like the one of which we have been talking.
I hope that the Sea- Anemone has interested
you so much, that you will like to hear about
some other animals of the same kind, which
live also in the sea, and of which I have a
strange and wonderful story to tell you, tiny
little creatures, some of them no larger than a
pin's head, yet they have built up large islands,
16 SEA- ANEMONES AND CORALS.
and even considerable portions both of Europe
and America. These are the coral animals ;
and though they do not live on our northern
coasts, so that you cannot therefore see them
alive, and are much smaller than our Sea- Anem-
one, yet, as many of them are constructed on
the same plan, what I have told you about his
tentacles, his partitions, his internal sac, his lasso-
cells, may help you to understand what I have
to tell you of the coral animals. They do not
live singly, like our Sea- Anemone, whom we
found all alone in his puddle, but they grow
together in clusters. Such clusters, however,
start from a single little animal ; it is born
free, a little pear-shaped, soft animal, white and
jelly-like, swimming about in the water.* It
moves with great rapidity, be-
cause it is covered all over
with a little vibrating fringe,f
No. 7. No. 8. an d that fringe moves with
incredible quickness, and keeps the little Coral
in constant rapid motion. But when it finds
* The young, just hatched, of Porites, a Coral, found on the
Reef of Florida. No. 7 seen from the side; No. 8 from above,
t Vibratile Cilia of Physiologists.
SEA-ANEMONES AND CORALS. 17
a suitable place at such a depth in the sea
as it likes, and where the water is clear and
bright, for it does not fancy muddy or sandy
water, it attaches itself either to the rocks or
the sea-bottom by one end, which flattens and
adheres to the ground, while the other spreads ;
and the whole has a cup-shaped form a little
depressed at the top.* That depression marks
where the mouth is presently to be, and be-
fore long it becomes a hole in the centre, and
all around it feelers or tentacles begin to ap-
pear. You see by the picture, that it looks
very much like our Sea-Anemone, though it
has not so many feelers; but then the Sea-
Anemone, when young, has not more. It is
only in its full-grown condition, that it has
the numerous tentacles which the picture rep-
resents. The sides of the coral animal begin
to thicken, the sac which is the stomach forms
in the centre, and also the partitions dividing
the rest of the body. If we could make a
cut across the little Coral, we should see that
he is formed inside like our Sea- Anemone ;
we should see the cavity in the centre formed
# The same as wood-cut 7, seen from above.
2
18 SEA-ANEMONES AND CORALS.
by the stomach, and the partitions spreading
from it like the spokes of a wheel. But I
must explain to you a very important differ-
ence between them and the Anemone, which
will help you to understand the long story I
have to tell you about these wonderful little
animals, who play such an important part in
the history of the world.
We have seen that our little Sea- Anemone
is soft throughout, he is just like a mass of
jelly, and though the parts of his body are
quite distinct, yet his partitions, his tentacles,
the walls of his body, and the sac serving him
as a stomach, are all quite soft, and he can
change his form, contract all his parts, and roll
himself up like a little ugly lump, just for the
reason that the whole of his substance is pul-
py and gelatinous. But with the Coral it is
quite different. It is true that when he is first
born, he is, as I have described him, a little,
oval, jelly-like animal, swimming about in the
water ; but after he has selected his resting-
place, has grown larger, and his mouth, his
stomach, the partitions of his body and his ten-
tacles are formed, then begins a process which
SEA- ANEMONES AND CORALS. 19
ends in giving him a very different character
from that of the Anemone. There are hard
particles of lime in his substance, and these
accumulate, first at the base of the body, where
it is attached to the ground, so that it becomes
quite firm and solid, then in all the partitions,
so that they become like little solid walls, and
in the sides of the body, so that they too grow
quite hard ; and now the whole has a solid
frame, the only parts of the little creature which
remain soft, being the summit, the mouth, the
fringes around it, and the stomach within.
I have said that the coral animals grow in
clusters, but thus far I have only described the
single animal that begins the coral stock. Now
I will show you how he mul-
tiplies himself, till, instead of
one animal there are count-
less multitudes living together
in one community. The ad-
joining figure shows you a
part of such a community.*
When the first coral animal
No. 9.
has undergone the changes I
* A branch of full-grown Porites in natural size.
20
SEA-ANEMONES AND CORALS.
have described, and assumed its permanent
character, it begins to spread and grow taller,
and from its surface, either from the base
or from the sides, grow up other animals of
the same kind, remaining always attached to
the first, and increasing till they are crowded
together in hundreds and thousands and mill-
ions on one foundation. This way of grow-
ing is called budding, because it resembles a
little the branching of a plant, but each bud
is nothing but a new animal, remaining con-
nected with the preceding as the branches of
a tree with the stem.
The various kinds of Corals grow in differ-
ent ways and
vary greatly in
size, some be-
ing no larger
than a pin's
head. Some
bud from the
base, as in
the figure
which you see
- "TJPP^ in wood-cut
No. 10.
SEA- ANEMONES AND CORALS. 21
10 ; * others from the side, as in our little
picture here ; f in oth-
ers, each animal widens
gradually toward the
summit as it grows,
assuming thus a sort
of trumpet shape, then
divides so that where
there was but one
mouth, there are now
two, as you see in the picture, $ and these again
may spread and divide
in the same manner, so
that the cluster goes
on increasing in that
way, one animal di-
viding into two or
more, till they become
a cluster. In another
kind, the individuals No. 12.
do not divide and widen as they grow higher,
and cannot therefore, by spreading, fill up the
spaces between, which enlarge with their in-
* Agaricia or Mycidium. f Caryophyllia.
Mussa.
22 SEA-ANEMONES AND CORALS.
creasing height; but in those spaces the new
buds form, thus filling all the intervals, and
making a coral mass covered all over with
thousands of closely packed pits, which mark
the spots occupied each by a little animal.*
Others grow in lighter
branches, so like plants
that I am sure, if you
looked into water where
numbers of these sin-
gular animals were grow-
ing in the sea, wav-
ing their branches to
No - 13> ;and fro, like an ocean
shrubbery, you would suppose they were gi-
gantic but exquisite sea- weeds, rather than
living beings. On these branches are crowded
thousands of these little creatures, living a
common life, and building up coral groves
under the water. Here you have a little
picture of one commonly called the Sea-Fan,f
which, -when living, is particularly beautiful, on
account of its ornamented tentacles. They not
* Astrea: heads of this kind measure frequently several feet
across.
t No. 14 Gorgonia.
SEA-ANEMONES AND CORALS.
23
only form a fringe around
the summit of the animal,
but they are themselves
fringed, or lobed, along
their edges. The wood-
cut represents only a small
branch, but they grow to
the height of several feet.
Among the branching
Corals, there is one kind,
the so-called Finger Cor-
al,* which differs from the
others in having a
somewhat larger ani-
mal on the top of
each branch, with
smaller ones all
around the stem and
branches. They rep-
resent, as it were, the
patriarchal heads of
the family, occupy-
ing the seat of honor
at the summit of
No. 14.
No. 15.
Madrepora.
24 SEA-ANEMONES AND CORALS.
every branch, while the little ones grow around
and below them.
I dare say you have seen specimens of Cor-
als, because they are so beautiful that all who
travel to the tropical oceans where they grow,
to the coast of Florida, to the Pacific, and
the East Indies, bring home specimens of
them. But when we see them at home, as
they are brought from foreign lands, we must
remember that all the soft and moving parts,
the tentacles or fringes that wave so grace-
fully in the water, are gone ; for they decay
when the animal dies, and nothing remains
but the hard frame which I have described
to you. Notwithstanding this, however, we
can see in such a mass of dead Coral the
spot where every little animal has lived. Some
of them form round masses which are called
coral heads. Such coral heads differ in ap-
pearance according to the method of grow-
ing of the coral animal by which they were
formed. In a dead coral mass, for instance,
made by those animals which have the trum-
pet shape, and which increase by spreading
and dividing, the marks that are left are more
SEA-ANEMONES AND COEALS. 25
uneven, forming undulating lines on the sur-
face.* In that which
does not widen as it
grows, but in which
the spaces are filled
by the budding of
new animals, the holes
are quite regular, and
have a star-shaped
figure, (see wood-cut
No. 13,) produced by
the partitions arranged No. IG.
like the spokes of a wheel, as I have described
them to you in the single little Coral and in
the Sea- Anemone. All Corals of the kinds I
speak of are formed in this way, whether they
grow in branches or in round masses, whether
they bud from the base or from the side, or
increase by division ; the structure of every
separate little animal is the one that I have
tried to explain to you.
Persons who have not had an opportunity
of watching the Corals when alive, and have
only seen the dry coral heads with their reg-
* Meandrina.
26 SEA-ANEMONES AND CORALS.
ular pits throughout, often talk of coral in-
sects as building the Corals, comparing them
to the bee that builds its honeycomb. But
this is not correct. There are no coral in-
sects, for insects are entirely different from
the coral animals, and the hard Coral is com-
posed of the solid frame of the animals them-
selves, their skeletons as it were, instead of
being a structure which they build to live in,
as the bee builds its honeycomb. The honey-
comb is truly a kind of house the bee con-
structs for itself, to live in and to lay its eggs
in, and to fly out of and into at will. But the
cells in a coral head are a part of the coral
animals themselves, and though they can with-
draw their soft parts into their solid frame, or
expand them at will, they cannot be separated
from it, for it is as necessary to their life, and
as much a part of it, as our bones are a part
of our bodies.
There is one thing I have not told you
about these animals, and that you will think
very odd in their way of living. They are
all connected with each other, the body of
each one opening at its base into that of the
SEA-ANEMONES AND CORALS. 27
next, so that what enters in at the mouth of
one, after circulating in his body, passes into
the next, and thus you see when one eats his
dinner, it nourishes not only himself, but all
his neighbors too.
28 CORAL REEFS.
t CHAPTER II.
CORAL REEFS.
I HAVE told you that these strange little
beings have built up large islands and parts of
continents, and I hope with what I have said
of their way of growing, of their solid frame,
and of their living in such crowded communi-
ties, forming large hard masses, you will be
able to understand how these busy little ani-
mals, who in order to fulfil their appointed
work have only to grow, have helped to make
the world.
"We will suppose that under the level of
the ocean there is an island or a rocky hill
growing up from the bottom of the sea, which,
if it became large and high enough to be seen
above the water, would be what we call an
CORAL REEFS. 29
island. Perhaps you think of the bottom of the
ocean as one great level floor, I remember I
did, when I was a little girl ; but in the ocean,
as well as on land, there are hills and valleys,
and even mountain chains. Suppose then that
there were an elevation under the sea which, if
it rose higher than the water, would be an isl-
and, but which stops at a depth of ten fathoms
below the surface. Here we have its picture.
Now fancy that
some of those
'''IIIMnllfl'ilH'''"
^%l!IWilil!ffiiP'lll|!!!
little coral ani-
mals I have
described as No. 17.
swimming about freely in the water when
they are first born, should attach themselves
upon the side of this island and should begin
to bud and spread in large coral heads all
around it. We must remember that it is not
only by budding that they increase, but also
by eggs, which when hatched are the little
pear-shaped free Corals which float about for
a while, and then fasten themselves upon the
community, so that they not only multiply by
dividing and branching, but also by the ad-
30 CORAL REEFS.
dition of all the little animals that are born
from their eggs. As this coral bank grows,
the lower ones gradually die, their solid frames
still remaining to form a firm foundation for
all that grow above them. All the cracks and
crevices are filled with sand, bits of shell, &c.,
so that it makes a wall as strong as any
masonry. When they have, by their growth,
formed a ridge all around the island, they
begin to grow upward from the foundation
which they have laid, thus raising a circular
wall about it. But when they have reached a
certain height in the water, those Corals, which
like deep water, will no longer grow there, and
they die out ; but on the surface that they
have prepared, new kinds, which like the shal-
low water, begin to establish themselves, and
they continue the wall the others had begun.
As it goes on increasing in height, these also
find the water too shallow for them, but now
to complete the work come in the branching
ones, which I have described to you as resem-
bjing sea-weeds and plants, and so the wall is
crowned by a waving shrubbery. This brings
it at last to the surface of the water ; and now
CORAL REEFS. 31
^^PiP^ ^1!MMI
our island is surrounded by a circular wall, ris-
ing to the level
of the sea. But
above that no
Corals can live,
and therefore as No - 18 -
soon as the wall rises above high-water mark,
the work of the little builders is done, they
can bring it up no higher, and they die for
want of the constant action of the sea-water.
But now other influences come in to complete
the structures. The waves beating against the
coral wall wear away its surface, break off large
pieces from it by constant rolling and grinding,
wear them into sand, and in storms these bro-
ken masses of coral rock, and quantities of coral
sand are thrown up on the top of the wall.
Gradually all the scattered materials floating in
the sea around settle upon it, and the summit
becomes covered with a soil composed of
broken coral masses, sand, mud, parts of shells,
drifted sea-weed, &c. And now perhaps birds
drop there the seeds of some plant, or such
seeds are floated from some neighboring shore,
trees spring up there, flowers and grass grow
32 CORAL REEFS.
upon it, men come and settle there, they
build their houses and plant their gardens on
our circular island, which lies like a green ring
on the sea and incloses within it a calm ocean
lake. And so you see these tiny creatures,
many of them no larger than a pin's head,
build up from the ocean depths, lands that
may grow green and luxuriant with the beau-
tiful vegetation of the tropics and in which men
may find a pleasant home.
I should tell you that all coral structures,
while the Corals are building them, and before
they are transformed into land, are called reefs.
I have spoken of the circular one which I have
been describing as a wall, because I thought
you would understand my meaning better ; and
they are truly walls. But the common name
for them is reef, and the coral animals are
called reef-builders.
There are other kinds of islands which are
built by Corals ; sometimes they build around
an island which rises above the level of the sea,
and then, of course, the centre is filled with
solid land, instead of being a lake inclosed by
the coral growth, as in the one I have been
CORAL REEFS.
33
describing. The circular ones we have been
talking about, are Lagoon Islands. There are
many of them in the Pacific Ocean. When
people first made voyages in the Pacific Ocean,
they could not at all understand the meaning of
these islands, formed like rings, with calm water
in their centre. Usually when the islands are
large, they do not close completely, but some-
times one or more gaps are left in the ring,
through which vessels can pass in, and anchor
in the quiet harbors formed within the shelter
of these coral banks with the trees that grow
upon them. You may imagine how surprised
voyagers must have been, when they first
sailed through such an opening in a circular
coral island and found themselves in a quiet
lake in mid-
ocean. Some-
times these
coral structures
are made into
Lagoon Islands
by the sinking
of the land around which they have begun
to grow. Suppose, for instance, that Corals
No. 19.
34 CORAL REEFS.
establish themselves around an island, and the
island gradually subsides below the level of
the sea, as islands are often known to do in
the Pacific Ocean ; the Corals continue to grow
upward as the island continues to sink, and by
the time the Corals reach the level of the sea,
the island is out of sight, nothing being visible
but the ring of coral bank, with water in the
middle.
I have told you that not only are islands
built up by Corals, but parts of continents also ;
and I will show you how the whole peninsula
of Florida has been patiently added to the con-
tinent of North America on which you live, by
these busy little reef-builders, during so many
thousand years, that you would find it difficult
to count the centuries.
Do you remember how Florida is shaped and
situated, like a long tongue of land running out
into the Gulf of Mexico ? Here is a picture
of it. Outside, at a little distance, you see,
there are a number of islands, called Keys, lying
in a curved line around it, and about five miles
beyond these islands, if you could look below
the water, you would see a crescent shaped wall
CORAL REEFS.
35
growing up from the sea-bottom ; but as yet it
rises to the surface of the water only in two or
three spots, and then only as points of rock,
where light-houses and beacons are placed to
warn away vessels ; for if a ship drives in upon
that treacherous wall beneath the water, she
may be broken to pieces. Can you fancy who
36 CORAL REEFS.
has been building that wall ? I think you will
say at once that here also our little masons of
the sea have been at work, and so it is. The
Coral-builders have been erecting that wall, but
though they have been at work upon it for
many thousand years, they have not yet suc-
ceeded in bringing it to the sea-level, except at
two or three points, as I have mentioned. They
are not however discouraged, they are far
more patient than little boys and girls, more
patient even than men, and they will go on,
adding little by little to their wall, till they have
joined it to the mainland of Florida.
But they cannot do this all alone, other
agencies must help them ; and in order to
understand how this is, we must look a little
at those islands lying within the outer wall,
and at the space that divides them from the
mainland. Those islands are part of a coral
wall exactly like the one outside of them, be-
low the water, and the islands are those parts
of it which have reached the surface, and on
which a soil has been formed by the collec-
tion of sand, mud, broken shells, coral, sea-
weed, &c. There, as on the circular islands of
CORAL REEFS. 37
the Pacific, trees and flowers grow, and people
live, and if you were to see some of the beau-
tiful gardens of Key West, the name of one
of these islands, with their tropical flowers of
the most brilliant hues, their cocoa-nut trees,
their banana trees, and their delicious fruits, and
the pleasant houses that stand in the midst of
all this beauty, you would hardly believe that
on this spot, not very long ago, the waves
washed over the little Coral-builders. There
are, as you see by the wood-cut, several of these
islands, all formed in the same way, by those
parts of the inner coral wall, that have risen
above the surface and have become covered
with soil. Between these islands and the main-
land, the present coast of Florida, all the space
is filled by mud flats, that is, by a large col-
lection of mud, formed by the washing of the
sea against the shore and against the coral reef
wearing it into sand and mud, which has been
heaped up in the channel between the line of
islands and the shore, till it fills it completely.
I think that, with these facts, we can see
how, in the course of many years, the solid
land of Florida will extend to where that outer
38 CORAL REEFS.
coral wall now runs beneath the surface of the
water. The mud flats will increase by the con-
stant addition of all the mud, sand, broken
shells, and materials of all sorts, that float
about in the channel between the coast and
the islands, till they are raised to a level with
them, and connect them by solid ground. The
wall, of which the islands are only those parts
that have grown more rapidly here and there,
will complete its growth, and rise above the
level of the sea for its whole length. The outer
reef, now rising only in two or three rocky
points above the sea level, will gradually form
islands here and there, as the inner one now
does, and between those islands and the inner
reef, which will then be the coast of Florida,
mud flats will collect and fill the space. The
outer reef will then gradually complete its
growth, no longer remaining a series of islands,
but becoming a long strip of land ; the mud flats
will unite it to the inner one, and then there
will be solid ground all the way from the
present coast of Florida to where the outer
coral reef now runs beneath the sea.
This will take place in centuries to come ;
CORAL REEFS. 39
but it actually has taken place, to the north of
the present reefs, during thousands of years
past, and the whole peninsula of Florida has
been formed by the same process that is going
on at its southern extremity now. All that part
of Florida which has been examined is found
to be formed in this way, first a reef and then
a mud flat, and then a reef and then a mud
flat, one within the other, just as they lie now
at the southern end. Seven such reefs and
mud flats have been discovered already, and I
suppose there are many more in the northern
part. Of course, without digging down below
the surface and studying the formation of the
ground, we could not detect this, because for
centuries all traces of those old reefs and mud
flats have been covered with soil and grass and
trees and flowers. We should no more sus-
pect, from its present appearance, that Florida
had once been the ocean home of the reef-
builders, than the people who live centuries
after us will suspect that what will then be its
southern extremity, was, in our time, almost
entirely under water.
You may ask why the little Corals do not set-
40 CORAL REEFS.
tie nearer the shore, and connect their reef im-
mediately with it, instead of beginning at a
distance of three or four miles from the shore,
thus leaving a channel to be filled up afterwards
by mud flats. The reason is this. The Corals
which form the foundation of the reef delight
in deep water, and could not live in the shallow
waters of a sloping shore, and they like also
perfectly clear water, untroubled by the mud
and sand washed off from the land by the
waves. They naturally seek the conditions
most favorable for their growth, and establish
themselves at a little distance from the coast,
where they find the deep, untroubled waters
which they need.
There are other kinds of Corals beside those
that I have described here, some that are
vegetable, a kind of stony sea-weed, as it were,
growing hard from the quantity of lime par-
ticles it contains ; and others which, like those
we have been speaking of, are little animals,
differing somewhat from them, however, in the
arrangement of their parts. But it is not ne-
cessary, in order that you should understand
the building of a coral reef, to explain to
COKAL REEFS. 41
you the different nature of all the Corals that
compose it.
Florida is not the only country that has been
built up in this way. One of the most beauti-
ful parts of Switzerland, called the Jura, lying
on the border between Switzerland and France,
is formed of coral reefs such as are now form-
ing in Florida. If you look at your map of
Europe, you will see what great changes must
have taken place since then. Now you see
Switzerland is completely shut out from the
sea ; it lies between France, Germany, Austria,
and Italy, and is land-locked on every side.
But, as we know that Corals can only live in
the sea-water, it is evident that in the days
when they were building up the Jura, the ocean
must have washed the shores of Switzerland
on its western side, and the southern part of
France cannot have existed at all.
The structure which I have described to you
in the Sea- Anemone and the Coral, belongs to
many other little beings having their home in
42 CORAL REEFS.
the sea, and all animals so constructed are
called Polyps. That is their scientific name,
and it includes thousands of animals which,
however they may differ in external form, have
their parts arranged internally in the same way.
HYDROIDS AND JELLY-FISHES. 43
CHAPTER III.
HYDROIDS AND JELLY-FISHES.
OUR walk, beginning at Nahant, has ex-
tended rather far, has it not? Let us come
back now from Florida and the Corals, and
the strange old times when the reef-builders
were contributing their share toward one of
the most beautiful countries in the world, and
see what else we can find that is interesting
among the animals living close about our
own home.
In many of the pools left by the retreating
tide along our beaches and rocks, such as
that in which we found our Sea- Anemone, we
may find little animals resembling flowers even
more than that does, because they grow in
clusters like miniature shrubs. Here we have
44
HYDROIDS AND JELLY-FISHES.
No 21.
a picture of one.* You
will hardly believe that
it is built on the same
general plan as the
Anemone, when its ap-
pearance is so different,
but you will soon learn,
if you watch animals, that
their external form may
differ very much, and yet
that they may be con-
structed according to the
same plan. If we examine each of these little
animals, hanging like flowers at the summit
of each slender stalk, we shall find that they
have many of the features belonging to the
Anemone and to the Coral. They have the
wreath of tentacles, looking like a fringe
around the mouth, and the mouth opens into
a cavity in the middle, which is the stomach ;
but they have not the partitions that in the
Sea- Anemone and the Corals divide the rest of
the body into separate parts ; nor is the stomach
a sac hanging within the body, as in the Sea-
* Tubularia.
HYDROIDS AND JELLY-FISHES. 45
Anemone, but it is a cavity hollowed out of
the substance of the body. If we look at the
slender stalk with a microscope, we shall find
that, instead of a stalk, it is a hollow tube,
connecting with the central stem, which is
also hollow. In this community of animals,
as in the coral community, each one is con-
nected with the next by these stems, so that
all the water and food that enters in at the
mouth of one, feeds all the rest.
There is one very odd thing about these little
animals ; the young that are born from them
are quite different from themselves. You know
that usually the young of animals are like
the parents. From the eggs in our hens'
nests, chickens are hatched ; from the pretty
blue eggs in the robin's nest, come forth the
little robins ; and I think you must remember
the funny little turtles that came out of the tur-
tles' eggs, which we kept in a box of earth two
summers since, to see what would become of
them. We should naturally suppose, then, that
from these little Animals which I have been de-
scribing, there would be born animals like them-
selves, just as chickens are born from hens' eggs,
46
HYDROIDS AND JELLY-FISHES.
No. 22.
robins from robins' eggs, and tortoises from tor-
toises' eggs. But we shall see that this is not so.
We will suppose that we
have carried home one of these
little clusters, differing some-
what from the preceding, and
put it in our Aquarium. Here
you have its picture.* A day
or two after we may find
swimming about in the water
a little, fairy like, transparent
thing, so slight and delicate
indeed that it seems almost
as if some drops of the water
had taken form and shape,
and that this strange little
being, that is darting about
in it, were but a part of the
element in which it floats.f
In shape it is like a tiny cup
turned upside down ; from the
lower side hang four long
threads ; in the centre of the
lower side hangs a proboscis,
No. 23. tne enc * f which is the
* No. 22, Coryne. t No. 23, Sarsia.
HYDROIDS AND JELLY-FISHES. 47
mouth, and four tubes run from the summit
of the upper side to the lower edge, where
a circular tube unites them all around. It
seems to delight in its life, it shoots through
the , water in every direction, and appears
to move by breathing, for every motion is
made by a sudden contraction and expan-
sion, which is in truth produced by the tak-
ing in and throwing out of water under the
cup. Up and down, and on every side it
darts about, and no bird can enjoy its flight
through the air more than this animal, which
scarcely seerns to have a material body, so
frail and unsubstantial is it, appears to enjoy
its freedom of motion through the water. It
is perfectly transparent; a drop of water, a
bubble of air, a spider's web, a fly's wing,
anything that has form and shape at all, can
hardly be more slight in texture than this
little creature. And this is the being pro-
duced from the cluster of animals, so different
from itself, which we brought in and placed in
our Aquarium. If our eyes had been sharp
enough, or we had been in the habit of using
the microscope, we might have seen that, very
48
HYDROIDS AND JELLY-FISHES.
near the tentacles around the mouth of each
one of the little animals, were hanging bunches
of little spheres.* These
are buds, quite different
from the buds of the stem,
and from them are born
the singular little creatures
such as the one I have
just described.
Let us watch him now
for a while, and see what
becomes of our fairy friend.
NO. 24. From the centre of the
lower side hangs down, as I have said, a kind
of proboscis, (see wood-cut 23.) I use that
word, because it is the one used by natural-
ists to describe the thing ; but I hope it will not
remind you of an elephant's proboscis, which I
suppose is the only connection you have ever
heard the word used in. If you ever exam-
ine the almost imperceptible and transparent
organ attached to this little creature, called
by naturalists a proboscis, you will wonder
* No. 24. Ahead of Coryne magnified, of which a great many are
clustered together in wood-cut 22, where they are shown in natural
size.
HYDROIDS AND JELLY-FISHES. 49
that the same name should be used to describe
two things, one of which is so delicate, and
belongs to such a slight and transparent ani-
mal, while the other is so heavy, and belongs
to one of the largest and clumsiest animals liv-
ing. Along this proboscis, little spheres are
scattered, which are eggs. From these eggs are
born little pear-shaped bodies, very like those
which I have described to you as the single
coral animal (see wood-cut 7) before it has
grown into a coral stock. It swims freely about
for a while, then becomes attached to some shell
or sea-weed or stone, puts out first a few tenta-
cles,* then gradually more, then buds
from the base and from the side, and
grows at last into a cluster of animals,
a little shrub, like the one with which
we began. So you see, with this No. 25.
animal, it is not the child that resembles the
parent, but the grandchild that resembles the
grandparent, and we must go through two gen-
erations before we come again to the form with
which it started.
The little animals which grow in clusters are
* Young Hydroid of Coryne.
4
50 HYDROIDS AND JELLY-FISHES.
all called Hydroids, though there are a great
variety of them distinguished from each other
by special names, with which I will not bur-
den your memory now. Those which are born
from them are called Jelly-Fishes, though of
these also there are a number differing in form
and size, having also their special names.
You must not fancy from this that these ani-
mals are in any way connected with fishes.
They are no more like a fish than a bird is like
a fish, but this common name has been given to
them because anything that lives in the water is
apt to be associated with fish by people who
know nothing about them, except the fact that
they inhabit the sea.
There is one of these Hydroids living as a
single animal, not in a community or cluster
like the one I have described, which is exces-
sively small, perhaps half an inch high, and yet
produces some of the largest Jelly-Fishes. It
does not bear them by buds or eggs, as I shall
show you, but by dividing itself into
a succession of animals, each one of
which is a Jelly- Fish. Here is a pic-
Hydroid somewhat magni-
HYDROIDS AND JELLY-FISHES.
51
No. 27.
fied, and before this process
begins ; and here in another
picture of the same after it
has begun to divide, and very
much enlarged, in order to
show you how this change takes place. After
the little Hydroid has lived
for a time as you see him
in the first picture, a single
animal attached to the rocks
or sea-weed, the upper part
begins to contract, then an-
other contraction takes place
a little lower down, and so
on till the whole animal
is divided by contractions No. 27 .
through all its length, and it looks something
like a pile of saucers.* Then each one of
these contractions deepens
more and more, till each part
that has been so marked
off, separates from the rest,
and swims away a free an-
imal, shaped like the pic- N O . 28.
* Strobila
52 HYDROIDS AND JELLY-FISHES.
ture here.* After this separation has taken
place, the tentacles begin to grow, and when
the animal is complete, it is bordered all
around the margin by the fringe which they
form. You see that in order to have the
bulging side above, as it is in the picture,
each one as it floated off must have turned
upside down, for if they retained the position
which they have while still attached together,
their shape would be like that of a saucer,
standing on its bottom, as it is usually placed.
But each one, as it leaves the pile turns a
somerset, and though it has still the shape of
a saucer, it is of a saucer overturned and rest-
ing on its edge, the edge being scalloped, for
the fringe of tentacles around the margin is
not yet fully formed.
There are a variety of these singular, self-
dividing Hydroids and of the Jelly-Fishes pro-
duced by them, all of which grow to a con-
siderable size. The most common is the
white sun-fish, f so called, seen in our bays
and along our wharves. It is remarkable on
* No. 28. This jelly-fish has been described as Ephyra.
f No. 29. Aurelia.
HYDROIDS AND JELLY-FISHES. 53
account of four crescent-like figures of a rosy
or purplish color, so placed as to form a cross
No. 29.
in the centre. These are produced by the
large accumulation of eggs forming these
crescent-shaped bunches. Another Jelly-Fish,
produced in the same way by the division of
a Hydroid, is much larger, varying in circum-
ference from that of a dinner plate to that
of a large tub, (I have often seen one filling
completely the largest sized wash-tub,) and
with immensely long tentacles hanging from
it. When one of the largest of these ani-
mals is swimming in the sea, its tentacles
may stretch out for twenty or thirty feet be-
hind it. The color of this Jelly-Fish is a deep
claret, and it is by no means so transparent
and delicate as the others I have described.
Yet, though it has a great deal more solidity, it
54 HYDROIDS AND JELLY-FISHES.
is soft nevertheless, of the consistency of jelly,
and after the autumn storms it is seen in
large numbers strewn upon the beach like
immense cakes of brown jelly. So large a
part of the weight of Jelly-Fishes is derived
from the water they absorb, that a Jelly-Fish
weighing, when taken from the sea, thirty-
five pounds, if left to dry in the sun will
shrink to a film weighing only half an ounce.
All those jelly-like masses which s'ometimes
lie stranded in such numbers along the beach
in summer, and which are often called Sun-
Fishes, are Jelly-Fishes of different kinds.
There is one of the Hydroid communities
that is curious and interesting, because each
individual in it has its appointed work to do.
Some are the sportsmen and the feeders of
the community. It is their business to catch
the prey, and they are furnished with the lasso
cells which I described to you in the Anemone.
They fling out their long whips, and entangle in
them the little shrimps, shell-fish, or any other
food that may fall in their way. They have
also to eat and digest for the whole family, and
then the food, reduced to a pulp by the pro-
HYDROIDS AND JELLY-FISHES.
55
cess of digestion, passes through the whole
community by means of the stems, which, as
I have told you, are
hollow tubes, and
communicate with
each other. Next,
there are the swim-
mers, for this commu-
nity is not attached,
but floats freely in the
water; their office is
to move the whole es-
tablishment, and
one may see such a
Hydroid community
moving along like one
individual, though all
the motion is perform-
ed by these swim-
ming members alone.
Finally there are those
whose business it is No 3Q
to produce the buds, that bear the little Jelly-
Fishes, and so well is this wonderful commu-
nity regulated that each one performs his own
56 HYDROIDS AND JELLY-FISHES.
work faithfully and never interferes with the
affairs of his neighbor.* Of these singular
communities there are many kinds, one of the
most remarkable of which is the beautiful
animal, commonly known in the Gulf of Mex-
ico, as the Portuguese Man-of-War.f The
various individuals composing the community
hang down like long bright-colored stream-
ers, attached to a bladder filled with air, of
the size of a large pear, and not unlike it
in shape, with a crest rising above it, some-
times pink or purple, and sometimes blue
which catches the wind like a sail, and carries
it along like a little boat upon the surface
of the sea. From the lower side of the blad-
der hang all kinds of threads and bags, being
as many distinct animals of smaller kinds,
but having immensely long tentacles, capa-
ble of an extraordinary extension, sometimes
measuring many yards when stretched to
their full length. Nothing can exceed the
beauty of these brilliant little communities
as they are seen on the water, with purple
crest erect, their numberless graceful feelers
* Siphonophorse. f No. 30. Physalia.
HYDROIDS AND JELLY-FISHES.
57
and threads spread, sweeping proudly over the
surface of the sea, like a miniature ship un-
der full sail. It is for this reason, I suppose,
that the sailors have called it the Portuguese
Man-of-War.
This most beautiful kind of Hydroid be-
longs to tropical seas, and is never found on
northern coasts. But we have many varieties
of very pretty Hydroids on our rocks and
beaches which you can easily collect for your
Aquariums, all producing their own kind of
Jelly-Fish, and this, in its turn, bringing forth
again the same kind of
Hydroid from which it
came. Besides those I
have described, there is
one in which some of
the buds have somewhat
the shape of little bells.*
Here is a branch of one,
and you see that the
buds are not all alike,
but that one is longer
than the others, and has
* Campanularia.
No. 31.
58
HYDROIDS AND JELLY-FISHES.
No. 32.
no tentacles, and within you see a number
of little spheres. Those are the buds, about
to drop out as little Jelly-Fishes,* somewhat
different from the one I first
described, but equally delicate
*
and beautiful. It has not the
long threads hanging from it,
but tentacles surround its whole
lower edge like a fringe. From the eggs of this
Jelly-Fish will be reproduced again the little
flower-like Hydroid with its bell-shaped buds
from which it was born.
Then we have another Hydroid forming also
a little shrub-like community, which bears its
Jelly-Fish buds among
the tentacles at the
crown or summit of
each individual. The
Jelly-Fish born from it
has a strange name ;
it is called the hunch-
back,! on account of
No. 33. its singular, one-sided
shape. It is larger on one side than the other,
* Tiaropsis. t No 34. Hypocodon.
HYDROIDS AND JELLY-FISHES. 59
and on that side it has one long tentacle
with buds growing upon it. This
again produces the Hydroid from
which it was born. Here you have
a little picture of it.
There are still other Jelly-Fishes
and very beautiful ones, having no
connection with any Hydroid, and NoT 34.
simply reproducing themselves by eggs. They
may be found on our coasts, throughout the
spring and summer ; and I hope you will have
many a good ramble on the rocks and beaches
of Nahant to find both Hydroids and Jelly-
Fishes.
There is one thing I must not forget to
tell you about the Jelly-Fishes before we leave
them. They are the lamps of the sea. Have
you ever heard of the phosphorescence of the
ocean ? It is a strange light on the surface of
the water, in the midst of which occasionally
larger luminous globes seem to float, and fol-
lowing in the wake of vessels as they cut
their way through the waves, or seen at night
along the line of foam that breaks upon the
shore. There are a variety of luminous ani-
60 HYDROIDS AND JELLY-FISHES.
mals in the sea, and a part of this singular
illumination of the ocean is due to all of them,
but the Jelly- Fishes are the brightest and most
beautiful. The large ones float slowly like fire-
globes among the lesser lights, while others
sparkle like stars, or spread a more diffused and
paler light over the water. This luminous prop-
erty of the Jelly- Fishes belongs to their more
active and sensitive parts, and the light is more
perceptible when a vessel breaks the surface of
the sea, or where the waves break upon the
shore, because the disturbance of the waters in
which they float excites them into unusual bril-
liancy. It is easy to watch the action of this
singular quality in the Jelly-Fishes by keeping
them in glass jars in a dark place. If you
trouble the water by passing your hand through
it, they will begin to shine, and sometimes, if
you have one of the larger ones, you may see
the light run along the more highly organized
parts of the whole body. He seems to tell you
thus, in fiery characters, the story of his own
structure.
HYDROIDS AND JELLY-FISHES. 61
I have told you that all animals like the Sea-
Anemone, that is, with the stomach hanging
in the centre, and the rest of the body divided
by partitions, are called Polyps. As we have
come to the end of our talk about Jelly-Fishes,
I will give you their scientific name also. All
animals constructed like Jelly-Fishes, that is,
with a transparent, jelly-like body, traversed by
tubes like little channels running through it,
and with the stomach hollowed out of the sub-
stance of the body, are called Medusae or Ac-
alephs. Now I will tell you something about
Star-Fishes and Sea- Urchins, or, as I think you
have heard them called, Sea-Eggs.
STAK-FISHES AND SEA-URCHINS.
CHAPTER IV.
STAR-FISHES AND SEA-URCHINS.
WE will begin with an old friend of yours,
the five-armed Star- Fish that you have often
collected on the beaches. There is no trou-
ble in hunting
for these Star-
Fishes ; there is
scarcely a pud-
dle or sea-
weedy rock
along any part
of the Nahant
shore where
they are not to
No. 35. be found in
numbers, and if you ever have an opportunity
STAK-FISHES AND SEA-URCHINS. 63
of rowing in a boat around Egg Rock at low
tide, you may see them by hundreds, especially
at the side of the rock farthest from Nahant,
where there is a very populous Star-Fish settle-
ment. But, though you are so familiar with
their general appearance, I doubt whether you
know much of their habits of life, or of the
way in which they are made. You know that
they move about, but you do not know what
organs they have to serve them as legs ; you
know, if you have ever watched them when
alive, that their lower side is covered with all
sorts of appendages seeming to be in active
motion, but you do not know what office these
appendages have to perform ; you take it for
granted that they eat, but you do not know
where their mouth is, and I think you could not
tell me whether they have any eyes or not. Let
us see what is the meaning of these differ-
ent parts, and when you have them in your
Aquarium next summer, you will have more
interest in watching them and in learning
something of their habits of life.
In the centre, on the lower side, you will see a
small aperture which is the mouth, and that
64 STAR-FISHES AND SEA-URCHINS.
aperture, like the mouth in Sea-Anemones or
Jelly-Fishes, opens into a cavity which is the
stomach, and from that cavity, tubes run up
each of the arms to its extremity, so that their
food, passing from the stomach into these tubes
can circulate through the whole body. They
have a very singular way of obtaining their
food. They have no long tentacles like the Sea-
Anemone to catch their prey, but they turn the
stomach out over the food, enveloping it in this
way, and having so secured it, they turn it back
again. On the lower side of the Star- Fish, ar-
ranged along the centre of each ray or arm,
there are a number of small appendages that
look like short feelers ; they are almost con-
stantly in motion, and if you look at them
closely you will see that the end of each one
spreads very slightly into a club shaped extrem-
ity and has a small depression, forming a little
pit. These are their organs of locomotion ; they
are suckers, and are so constructed as to cling
closely to any surface they touch. When the
Star-Fish wants to move, he stretches one of
his arms in the direction in which he means
to go, and attaching his suckers to a rock or
STAR-FISHES AND SEA-URCHINS. 65
sea- weed, or any object near him, he drags him-
self along. You know, when you are climb-
ing a tree, and you come to a part of it where
there is no branch upon which you can fix your
foot to take the next step, you may stretch your
arms to some higher bough, and draw the rest
of your body up in that way. This is not un-
like the Star- Fish's way of moving ; he turns one
of his rays in the right direction, stretches his
suckers as far as he can, adheres by them
closely to the surface along which he is mov-
ing, and drags the rest of his body on by the
force of their adhesion. To be sure, it is a slow
and clumsy way of moving, but then the Star-
Fish is rather a dull fellow, and he is as well
satisfied if he has walked an inch or two in an
hour as you would be if you had walked a mile
in half that time. These suckers are placed
along the centre of the lower side of each ray,
as I have told you, and on each side of the row
of suckers along the edge of every ray there are
appendages of a different kind. These are stiff
spines, the object of which is not well under-
stood, but perhaps they serve as a protection to
the animal. Here is a picture of a single ray,
STAR-FISHES AND SEA-URCHINS.
which shows you the suckers and the
spines. At the end of each ray there
is a little red speck which is an eye,
so that, as they have five rays, they
have also five eyes, which I dare say
will give you a great respect for their
powers of vision. But let me tell
$ you that five of their eyes are by no
/ means so good as one of yours, and
indeed though these red specks are
No. 36. essentially organs of sight, it is very
doubtful how much they see with them. Per-
haps they are only receptive of light without
discerning any objects ; for though we call them
eyes, they have no complicated structure such
as our eyes have by which every object is dis-
tinctly drawn like a picture within them. Yet
I once heard a story of a Star- Fish which
inclined me to believe that, if they do not see,
they have at least some very keen perception of
what goes on about them.
Star- Fishes carry their eggs near the mouth,
and keep them safely by stretching their suckers
around them, and thus holding them fast. A
friend of mine was one day watching a Star- Fish
STAR-FISHES AND SEA-URCHINS. 67
in a large glass dish, which had its eggs folded
within the suckers in this way, and wishing to
examine the eggs more closely, he parted the
suckers, took the eggs away, and kept them for
some time. When he had finished his exam-
ination, he dropped them back into the dish.
At once, to his surprise, the Star- Fish seemed
to be aware that its eggs had been returned
to it, and moving towards them at its utmost
speed, (which is, at best, but creeping very
slowly,) it placed itself over them, folded its
suckers once more around them, and so took them
up again. Wishing to be quite sure that this
had not been accidental, he removed the eggs
again, put the Star-Fish into another and larger
dish, and having placed it at one end, and put-
ting also some obstacle in the centre of the dish
to divide it from the other side, he then dropped
the eggs in at the end opposite the parent, as far
from it as possible. The Star- Fish immediately
began its journey (now quite a long one for a
Star-Fish) toward its offspring, and having
reached them, covered them, and took them up
again as before. A third time, the experiment
was repeated, but always with the same result ;
68 STAK-FISHES AND SEA-URCHINS.
the creature perceived its eggs the moment they
were placed in the same vessel with itself, and
went at once to shelter and protect them. You
see by this it is not lost time to watch even
these lowest creatures that God has made. They,
too, care for and cherish their young, they have
certain ends to fulfil in life, and they enjoy the
existence that has been granted to them, as
well as the higher animals. We may study the
habits even of a Star- Fish with interest, when
we remember that these first stirrings of sense
and love of offspring in the humblest creatures
rise to their greatest glory as affection and rea-
son in man, and place him at the head of all
created beings.
Let us look now at the upper side of the Star-
Fish. It is studded all over with little knobs,
differing in color in different Star-Fishes, and
having the effect of a sort of inlaid work,
as pretty as any of man's devising, or even
prettier. (See wood-cut 35.) Between these
knobs, are very short, hollow tubes, so small that
you will not easily distinguish them, but it is
owing to them that the upper side of the Star-
Fish has its full and rounded outline. These
STAR-FISHES AND SEA-URCHINS. 69
tubes absorb water, and when a Star- Fish has
been left upon the rocks or beach by the retreat-
ing tide, its outline becomes comparatively flat,
but as soon as the tide comes up and covers it
again, it assumes its rounded shape once more,
by filling its whole body with the water which
enters through these minute tubes. If you watch
them when they have just been taken from the
sea, you may see the water oozing from these
tubes.
On the upper side of the Star- Fish, near the
centre, and between two of the arms, you will see
that there is always a round, bright colored spot.
That is a little sieve through which the water is
filtered as it passes into the five principal tubes
that run from the stomach to the extremity of
each of the arms. By this means a free circu-
lation is established through the whole body.
There are a great variety of Star- Fishes; some
in which the arms are very spreading, being
divided into branches and tendrils, as it were,
that extend in every direction, but yet bear the
same relation to the centre as the rays in the
one with which you are familiar; others in which
the arms are united for a part of their length, so
70 STAR-FISHES AND SEA-URCHINS.
that the compact centre is larger ; others in which
there are ten arms instead of five, and so on. I
will not tire you with the details of these varie-
ties, because, however their appearance may dif-
fer, the structure of one explains the structure of
all. In all these the mouth and stomach are
in the centre, the tubes extending through the
arms, the suckers and spines on the lower side,
the knobs and tubes on the upper side, and the
little sieve for admitting water into the body.
Those in which the arms are very slender and
long, or branching, however, have no eyes at the
tips.
There is one kind of Star-Fish of which I
wish to tell you something, not in order that
you may study it for yourselves, for it is not
found on our coasts and you may never have
an opportunity of seeing it, but because it re-
sembles the first Star- Fishes that ever were cre-
ated. It is found in the West Indies, in deep
water, and instead of moving freely about in
the water like the others, it grows upon a
stalk attached to the ground. Sometimes in
breaking up or blasting rocks, there have been
found upon them impressions that looked as if
STAR-FISHES AND SEA-URCHINS.
71
some large but graceful flowers, not unlike a
widely opened tulip or lily, only of great size,
had been roughly drawn there. At first, the
No. 37.
persons who found these strange old flowers, as
they seemed, buried in the rocks, could not un-
derstand how they came to be there, or what
they were, but from their appearance they were
called " stone lilies." But when they were
72 STAR-FISHES AND SEA-URCHINS.
more closely examined, and carefully studied
by naturalists, who were familiar with animal
structures, it was found that what looked like
a flower-cup was a kind of Star- Fish, growing
upon a tall stalk, which must have been at-
tached to the ground when the creature was
alive. And so they were no longer considered
as flowers of old times that had been hidden
away in the rocks, and they lost their pretty
name of " stone lilies," and are now called
Crinoids, the first animals of this kind that ever
lived.
You will wonder, perhaps, how we know
that they were the first. We know it because
they are found in very ancient rocks, where
are preserved the impressions of a variety
of animals that lived many thousand years
ago, Corals, Star-Fishes, shells, worms, queer
crabs, and strange fishes, old-fashioned crea-
tures, very unlike those living on the earth
now, that vanished away many, many cen-
turies ago, and only left their traces in the
rocks to tell us something of the story of those
strange old times, before man and the animals
living with him upon the earth were born.
STAE-FISHES AND SEA-URCHINS.
73
And perhaps you may ask another question,
how it happens that any animals could be
preserved in hard rocks ? At the time these
animals were buried there, these rocks were
not hard. Many kinds of rock are mud or
sand at first, and they become hard in the
course of time, by the continual pressure of
the layers of mud and other materials that
are constantly added year by year, till the
whole mass is consolidated into rock. Now,
during this process, which may last for centu-
ries, many animals die in the soft mud or sand
that is afterwards to become hard, and the solid
parts of their bodies are preserved there and
are built, as it were, into the forming rocks.
Let us look now at the Sea-Urchin, or Sea-
Egg. Though it looks
very unlike a Star-
Fish, it is almost ex-
actly like it in the
number and arrange-
ment of its parts.
The arms which are
stretched out in a five-
rayed Star-Fish, if
74 STAR-FISHES AND SEA-URCHINS.
drawn together and joined at the points, would
make a Sea- Urchin ; the rows of suckers and
spines arranged along the five rays in the Star-
Fish, are arranged in alternate rows up and
down the surface of the Sea- Urchin, the five
eye-specks at the extremity of the rays in the
Star-Fish, are drawn close together on the
summit of the Sea-Urchin, and the mouth is
placed at the centre of the lower side in the
Sea-Urchin, as in the Star- Fish ; but it has five
little teeth not to be found in the Star- Fish.
The tubes carried along the arms of the Star-
Fish, follow the line of the rays in the Sea-
Urchin, and the little sieve through which the
water enters them is on the upper side of the
body, between two of the rays. You may form
some idea of the way in which the difference
in the outline of a Star-Fish and a Sea-
Urchin is produced, by making five equal divi-
sions on the skin of an orange, leaving them
united at the base, then peel it off, and stretch
it out, you have a star with five rays, draw
the rays together, and unite them at the top ?
and you have again the round form of the
orange.
STAR-FISHES AND SEA-URCHINS. 75
The Sea-Urchin has one very peculiar habit.
He bores for himself a hole in the rocks, which
just fits him, and makes a very snug and
comfortable retreat. I have seen a dead Sea-
Urchin about as large round as a five cent
piece, packed away as closely as possible in
its hole, that fitted him as neatly as if it
had been cut with the nicest instrument.
Their mode of making these holes is not
known, and as they are found in all kinds of
rocks, whether hard or soft, where Sea- Urchins
exist, in granite or basalt, as well as in lime-
stone or sandstone, it is difficult to under-
stand how animals not furnished with any
sharp and powerful instrument can produce
such an effect. There is, however, no doubt
that these holes are made by the animals
themselves, not only because the Sea-Urchins
are found in them, but because they fit their
inhabitants so perfectly, that no animal not
exactly of the same shape and size could have
produced them ; and they are of all sizes, from
that of the young Sea-Urchin to the full grown
one. It has been supposed by some natural-
ists that they were made by the constant fric-
76 STAR-FISHES AND SEA-URCHINS.
tion of a fringe that is in unceasing motion,
called the vibrating cilia, which, though in-
visible to the naked eye, covers the spines
of the Sea- Urchin, and by the constant turn-
ing of the animal over and over in the same
spot may wear a hole in the rock. It seems
difficult to believe that a substance so soft
and delicate as the vibrating fringes on these
animals should produce any effect on a sub-
stance hard as granite, yet we know that the
constant dropping of water wears away a
stone, and it may be that the continual fric-
tion even of the soft parts of the Sea- Urchin
would be equally effectual.
The common Sea-Urchin of Nahant is one
of those that make these singular holes, and
you may have an opportunity of seeing them
in the rocks there. I hope you will try to
find some Sea- Urchins for your Aquarium next
summer, and watch them in their living con-
dition. I dare say you have often seen them
dead and dry on the beaches, but you cannot
then judge at all of their appearance when
living. They look very pretty when dried in
that way, because, though they have lost all
STAR-FISHES AND SEA-URCHINS. 77
their spines and suckers, the spots where these
appendages were attached form a sort of pat-
tern in regular rows or zones over the surface
of the animal, and you can trace in this pat-
tern the lines along which the spines and
suckers were arranged when the animal was
living. The broader rays with the largest
spots are those along
which the spines were
attached, the narrower
ones with the smaller
spots crowded closely
together, are those along
which the suckers were
placed. N o. 39.
There is a great variety among the Sea-
Urchins as well as among the Star-Fishes.
They do not all burrow in the rocks. Some
of them are flat in form, and live on sandy
flats, burying themselves in the sand, so that
they are only discovered when left bare after
storms, or in very still days, when, in changing
their place, they have left tracks along the
sand.
There is another animal which, though it
78
STAR-FISHES AND SEA-URCHINS.
No. 40.
differs strikingly in appearance from the Sea-
Urchin and the Star-Fish is yet constructed on
the same plan.
It is commonly
called, from its
form, the Sea
Cucumber.* It
may be a little
difficult to show you how this soft elongated
animal, resembling a worm more than anything
else, is related to the Star- Fish with its extended
rays, or the Sea- Urchin with its round outline,
but I will try to explain it to you. Imagine that
the Sea- Urchin were elastic, and that taking
him at the mouth on one side, and at the spot
just opposite to the mouth where the rays meet
on the other side, you could stretch him out
till, instead of being a round, compressed ball,
he would have a long, cylindrical form like a
large worm ; you would then have an animal
like the one of which I speak. The rays would
of course be stretched out also, and would ex-
tend from one end of the body to the other.
This is the case witK the Sea- Cucumber. It has
# Holothuria.
STAR-FISHES AND SEA-URCHINS. 79
no spines, being soft throughout, but the suck-
ers are arranged in rows along the body, al-
ternating with spaces having no appendages,
but corresponding to those on which the spines
are arranged in Star-Fishes and Sea- Urchins.
The mouth is at one end of the body, and is
surrounded by a wreath of tentacles, and the
animal resting on one side, moves along like
the Star-Fish and the Sea- Urchin, by means
of the suckers, always turning that end of
the body at which the mouth is placed in
the direction of its motion. Its body is, as I
have said, soft throughout, and can contract
and expand, making itself broader and shorter,
or longer and narrower, by taking in or let-
ting out the sea-water, which enters at the
opening opposite the mouth, at the other end
of the body. The main tubes for the circula-
tion of food and water throughout the body,
answering to those which in the Star- Fish run
along the arms, and in the Sea- Urchins along
the rows of suckers, in the Sea- Cucumber ex-
tend from one end of the body to the other, and
the sieve through which the water is filtered is
within the body instead of being on the outside,
80 STAR-FISHES AND SEA-URCHINS.
as in the two others. The animals of this kind
that are found on our coast are very small.
But the larger kinds abound in the Bay of
Fundy and upon the mud-flats of the Reef of
Florida. Some of those from Florida are as
large as your arm and more than a foot long.
This curious animal furnishes a very impor-
tant article of food to the Chinese. They call
it the Trepang, and they send every year large
fishing fleets to the islands in the Pacific, and
to the coasts of New Holland, for the express
purpose of collecting it. When dried and pre-
served in a particular way, they find it a great
delicacy, though I doubt whether you or I
would like it very much.
As there is one general name, that of
Polyps, including all animals of the kind which
I first described, like the Sea- Anemone, and
another, that of Medusae or Acalephs, including
all of the second kind, like the Jelly-Fishes, so
*there is also a general name for all animals
like the Star-Fishes, Sea-Urchins, and Sea-
Cucumbers, that of Echinoderms. Each of
STAR-FISHES AND SEA-URCHINS. 81
these, the Polyps, the Acalephs, or Medusae, and
the Echinoderms form what is called by natural-
ists a class, and these three classes are included
under another name, that of Radiates. In other
words, Radiates form one great division of ani-
mals, embracing Polyps, Acalephs, or Medusae,
and Echinoderms. Now if you look in your
dictionary for the definition of the verb " to
radiate " you will find this : " to send out rays
from a centre." This explains the structure
of all the animals belonging to this division,
and the reason why they are called by this
name. Whether they are round or long or
star-shaped, they are all so constructed that
their parts diverge from a centre, and at that
centre is an opening which is the mouth.
This is the end of my stories about Radiates,
dear Lisa and Connie, and I hope you will
forgive this little bit of science and the hard
names at the close. If the account of them has
interested you, you will not find it difficult to
keep many of these animals, about which we
have been talking, alive in your Aquarium
next summer, and to learn a great deal of
their habits.
82 STAR-FISHES AND SEA-URCHINS.
If you like this little lesson in Natural His-
tory, I hope, at some future time, to write an-
other one for you about animals of another
kind, which are constructed on an entirely dif-
ferent plan.
THE END.
