Lessons

 

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OF THE

Rew Work State College of Agriculture
Lessons in zoology.Common animal forms.
LESSONS IN ZOOLOGY.

COMMON

ANIMAL FORMS

BY

CLARABEL GILMAN

THIRD EDITION, REVISED.

pat

BOSTON AND CHICAGO
NEW ENGLAND PUBLISHING COMPANY
CopysiIenHt, 1892,
BY
CLARABEL GILMAN.
PREFACE.

This little book is the outcome of ten years’ experience
in teaching elementary science. It embodies the outlines
of what I have found it wise to attempt with children,
and is offered to teachers with the hope that it may
prove suggestive and helpful. A special effort has been
made to remove stumbling-blocks, by explaining points of
structure that are likely to be puzzling, by giving minute
directions for procuring and handling specimens, and by
providing simple outline drawings that can be quickly
copied upon the blackboard by one who has little artistic
talent.

In general, the lessons are composed of two parts,—
one in coarse type, consisting of short, clear statements
of children’s observations, frequently in their own words,
with the facts that a teacher must sometimes supply in
order to make a lesson complete in essential points ; the
other in finer type, coutaining directions for the teacher
and additional facts, many of which the older children
can be led to discover for themselves. In some of the
lessons full illustrations have been given of the method of
guiding pupils’ observations by questions, which it has not
been thought necessary to repeat in the study of every
type, though the plan remains the same in all. If
ii Preface.

children are carefully taught to observe, describe, and
compare in the manner outlined here, it is believed
that they will have a good foundation either for the
later scientific study of zodlogy, or for the intelligent
observation of animal forms in nature.

I desire now to express my great indebtedness to
Prof. Alpheus Hyatt and Messrs. D. C. Heath & Co.
for the use of a large number of figures from the
admirable series of “Science Guides” published by the
latter. Their generosity has alone rendered it possible
to illustrate the book so fully, especially in the lessons
on insects.

The remainder of the cuts have been drawn from
various sources.

CLARABEL GILMAN.
May 14, 1892.
CONTENTS.

 

PAGE

Tur Sponar, - - - e : 5
Hypbra, - a o 11
SEA-ANEMONE, = < 7 = 15
CoRALs, = - - - 7 18
STar-Fisu, - 7 - = . 26
Sz URcHIN, . - - - 33
Cam. . “ é e 41
OysTER, - - - - 49
SNAIL, - - - - 54
Eartuworm, - - - - 59
LoBsTER, - - = _ 61
CRAYFISH AND CRAB, - - - - 69
HERMIT CRAB, - - - 72
BEACH-FLEA, - - - - - 15
SPIDER, - - : - - 8
GRASSHOPPER, - - - - - 83
CRICKET, - - - - - 89
BEETLE, - - - 92
DracGon Fy, - - - - 96
Bue, - - - - 99
CICADA, - - - 103
FLy, - - - . - 106
BUTTERFLY, - - - - 110
Mora, - - - 7 2 113
BEE, - - - - - - - 119

ANT, - - - - - 126
 

AWARD FROM

WORLD’S FAIR COMMISSION.

a

Lessons in Zoélogy received a diploma and bronze
medal from the World’s Fair Commission. The
award reads as follows:

AWARD.

“‘For a successful presentation of the subject

 

in a manner suited to the comprehension of a

 

child. The explanations and instructions as to

 

handling specimens are such as would lead a

 

beginner to lay a good foundation for future

scientific study. The illustrations are simple

 

and profuse, and can be reproduced on the

blackboard.”’

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|
:

I PP PP PPP POPP VOYOEOOPDPE

 
LESSONS IN ZOOLOGY.

THE SPONGE.

Lzsson I.

For the teacher, » bath sponge with one or two large openings
on the top; for each child, a straight wire hairpin and a slate
sponge, are the things needful for this lesson. Each sponge may
be cut vertically, almost to the base, through one of the large
tubes, or vertical sections may be used with the whole sponges.
The day before the lesson, each child should wash out his sponge
and notice how it is changed by the water. Sponges should always
be moist when studied. The hairpins are straightened out for use
as probes.

The children have already learned the following things:

The hard, dry sponges took in water through all the
little holes, and became soft and elastic. They are made
of threads called fibres, whose ends projeet in little brush-
like bundles on every side but one, and this side is darker
and smoother than the others. There are many small
holes in the sponge, and only a few large ones, or some-
times only one. One or two bright pupils notice that
there are holes all through the sponge, and a large tube
running straight down from the large opening.

Children will give some of these points spontaneously; others
must be brought out by skillful questioning.

Now, being careful not to tear the fibres, we put the
probes into the large openings, and trace the tubes (Fig.
1, @) into which they lead, almost to the base of the
6 Lessons in Zoology.

sponge. We put the probes into the small holes, and
find small tubes (Fig. 1, 6) leading from some of them
to the large tubes; from others, cross -tubes (Fig. 1, ¢)

 

Fic. 1. Vertical section of giove sponge frum Nassau, shown with
the flesh

connecting one small tube with another. Some of these
connecting tubes in process of formation show plainly as
channels on the surface, only partly covered in as yet by
little bridges of fibres. Besides these tubes, there are
others so smail that we cannot trace them out (Fig. 1, d)
passing in every direction through the mass of fibres.

A short talk about the home of the sponges ends the lesson.
The Sponge. 7

Let us find Key West and Nassau on the map. These
are the two principal markets for American sponges, which
live in the Caribbean Sea and off the Florida coast. If we
should visit Nassau, a boatman would take us out to the
sponge fisheries. The water is very clear, and with a water-
glass—a tube, or box, with a pane of glass at one end—
which we press against the surface, we can see the bottom.
Here and there on the coral rock, and contrasting with the
brightly colored fishes and the brilliant hues of the sea-fans,
are some dark masses fixed to the reef and sending out
little jets of water from openings in the top. These are the
sponges. We have in the boat a very long-handled fork,
with three prongs, curved so that they will take a firm
hold of the sponge, and with this our boatman pulls one
off from the rock. Sometimes they are taken in a dredge,
but the best sponges are brought up by divers. Our living
sponge has a dark brownish or purplish flesh that covers
all the fibres. After the sponges are killed by being ex-
posed to the air for a day, they are thrown into pens
made of stakes driven in shallow water, and left till the
flesh decays. Then they are washed and trimmed, and
sorted according to size, and afterward packed in bales
and sent to New York or London to market.

This is true of American sponges. Mediterranean sponges,
which are much finer and more expensive, receive more carefol
treatment.

Lesson II.

For this lesson every kind of sponge that the teacher can secure
will be useful.

Review of Lesson I. : The sponge is a mass of elastic fibres. The
edges of the fibres stand ont on every side but one, which is smooth
and dark. The sponge is full of tubes that open on the outside.
There are four sets of tubes: large tubes, small tubes that lead
from the surface to the large ones, cross tubes that connect these
8 Lessons in Zoology.

small tubes with one another, and microscopic tubes too smali to be
traced out. Our sponges come from the Caribbean Sea or tho
Florida coast, and were taken from the rocks with a curved fork or
a dredge. Mediterranean sponges are brought up by divers. When
alive they were covered with a dark colored flesh, but the flesh has
been removed, and only the fibres are left.

OUTLINE OF NEW WORK.

What was the use of the fibres? Not only to support
the flesh, but also to protect the animal. They are made
of a horny substance, and so tough that fishes very seldom

 

try to eat a sponge. The hard parts of a body, support-
ing and protecting softer ones, are the skeleton. Wehave
ovly the skeleton of our sponges. Which side was fixed
to the rock? We are sure it was the smooth, dark side,
because it appears to have been cut, and also because some
of the sponges have bits of rock caught in the fibres on
this side.

Where does the sponge get its food? From the water
The Sponge. 9

it takes in through the tubes. It takes in water through
the small tubes that we see, and the tiny ones that we
cannot trace carry it all over the sponge. When the
sponge has taken from the water the very smallest plants
and animals, which are its food, and has given carbonic
acid in exchange for oxygen, then the water passes out
through the large tubes. But as only the most minute
plants and animals can pass through the microscopic tubes
without danger of choking them up, a thin, porous skin

  

Fia, 3. Fic. 4.

like a delicate sieve covers the whole sponge except the
two or three large openings. But why does no water
enter at these? Because there is always a current flowing
out from them.

In little sacs (Fig 2*) all over the sponge are cells (a) bearing each
a microscopic whip (c), always lashing the water and producing the
currents that carry the foul water out through the large tubes as fresh
streams come in through the small ones. In these cella, too, the food
is digested. Though the outward current keeps the large tubes
open, yet if a living sponge is disturbed, it will contract so forcibly
as to close even these openings.

 

* Figs. 2 3, and 4 are highly magnified, while Fig. 5 is much reduced
from the natural size.
10 Lessons in Zotlogy.

Baby sponges can swim about in the water, but they
soon form a sucker at one end, by which they fix them-
selves (Fig. 3) to rocks, shells, or even the sea fans and
other branching corals, and after that they never leave
their home unless something tears them off.

Many sponges grow on our New England coast, but
are too brittle to be of any use. A little white sponge
that grows among shells in the mud just below low-water
mark, consists of small branching tubes about an inch long.
It has no fibres in its skeleton, but everywhere in its flesh
are little three armed bits of lime called spicules (Fig. 4).

The common fing er-sponge (Fig. 5) grows in large masses
on rocks and piles. The dark red and soft yellow masses
found in salt water, and the white flattened cakes often
cast up on the shore and dried hard in the sun, are all
sponges, the last named called by the sailors ‘“ seamen’s
biscuit.”

In a quantity of oyster shells there will usually be one
or two, at least, that have been attacked by the boring
spopge, which tunnels them through and through, and
fica’iy destroys them by dissolving out all their lime.
THE HYDRA.

A tiny green or light brown jelly-like lump as large as the head
of asmall pin; a slender stem, perhaps one fourth of an inch long,
with several tranaparent threads waving from ita tip; or a graceful
vase with a few blunt projections from the top; any or all of these
clingivg to water-planta or any other support in fresh-water ponds
or quiet streams, may be the hydra we are seeking. We tell the
children we are going to look for a new animal, and invite some of
the older ones to join usin a walk, thus enlisting their interest in the
hydra in advance. It is a wise precaution to fill our glass jars at
several different ponds, rather than to fill several jars from one
pond, because the fact that hydras have been found in a given
place one year seems to be no guarantee whatever that they will be
found there the next year. After the water has settled, the hydras
will expand and many of them will collect on the sides of the jar.
A dozen watch-crystals filled with pond-water, each with a bit of
duck weed or some other green water-plant, make excellent ponds for
as many hydras, in which children can examine them with magni-
fiers, watch them eat, and observe the different shapes they assume.
Pupils that are old enough will eojoy making a series of drawings
showing these different forms.

Four questions may be put upon the blackboard, one at
a time, for the children to answer from their own ob-
servations: What is a hydra? Where does it live?
What can it do? How do new hydras grow?

After a few days the answers to these questions will
bring out many of the following facts, in addition to those
already mentioned.

The hydra is a green or brown tube, attached by its
lower end to some support, and sending out several ten-
tacles near its upper end. Fig. 1 shows one magnified
many times, hanging mouth downward, from a bit of
wood. The upper end of the tube beyond the tentacles
is called the proboscis. At the end of the proboscis is
12 Lessons in Zodlogy.

the mouth, an opening leading into the central hollow
or stomach.

The tentacles are hollow, like so many glove fingers
pushing out around the mouth. They are the hydra’s fish-
ing rods, bearing numbers of little pockets, — the thread-
cells—on their sides, in which the fishing lines are coiled up.
Each line, instead of a hook at the end of it, has three
poisoned darts just where it issues from the pocket.

  

Fig. 1.

Fie. 3.

Fig. 2 represents a portion of a tentacle highly magnified,
with the thread-cells in clusters on its surface. Fig. 3
is a single cell after it has burst and the thread uncoiled.

When a tentacle touches a tiny worm or crustacean,
the pockets burst, and the lines entangle the prey in their
coils, while the poisoned darts quickly paralyze it. If
some creature too large to be paralyzed is caught by the
lines, then ensues a grand “tug of war” between that
and the hydra.

I once watched such a struggle between a hydra and the larva of

an insect, which lasted an hour and three quarters. Even then the
result was doubtful, but unfortunately the dish containing the com-
The Hydra. 13

batunts had to be moved, and the stirring of the water shook the
exhausted animals free from each other.

The hydra is extremely sensitive, and contracts at once
if touched. The variety of shapes it can assume, espe-
cially when digesting its food, is very wonderful.

 

Fic. 4-6.

There are buds on some of the hydras, which at first
look like knobs, then grow larger, form tentacles (Fig.
4—6), and gradually pinch themselves off from the
parent, and set up for themselves. In the autumn eggs
are produced (Fig. 1 a), which live through the winter.

 

In 1744, Trembley, a watchmaker of Geneva, performed
a remarkable series of experiments upon hydras. He
found that they can move about by turning somersaults
(Figs. 7-11) ; that if cutin small slices, each slice becomes
14 Lessons in Zoology.

a complete hydra; that if slit in various ways, a whole
colony may be produced from one (Figs. 12-13); and
when one is turned inside out, it goes on eating, and ap-
pears to enjoy life quite as much as before.

 

Fia. 12. Fig, 13.

In tide-poole and on the seaweed along onr coast we find grace-
ful, delicate, flower-like clusters, often mistaken for sea-mosses.
These are hydroids, or hydra-like animals, whose buds remain con-

nected and form colonies.
THE SEA-ANEMONE.

With living anemones this lesson can be made intensely intereat-
ing ; without them it should not be given to children. Those who are
not too far from Boston can send jars to the superintendent of
Essex Bridge, Salem, Mass., who will fill them at a reasonable price.
Young anemones can be brought as far as Boston, at least, simply
packed in wet seaweed. Nowhere else on our northern coast can
such a number or variety of anemones be seen as at Beverly Bridge.
The light piok or salmon colored ones show the structure best, for

 

Fig. 3. Fie. 2.

when fully expanded they reveal the partitions of the body-cavity
beautifully through their nearly transparent walls. Fig. 1 repre-
sents one fully expanded; Fig. 2, only partially. Very young
anemones, not more than an inch long, will show the connection
with the hydra, both on account of their small size and of their
having fewer tentacles than the full-grown ones.

It has been my experience that large ones do not thrive in eon-
finement, but they can be kept for some days if but one is placed
in each jar, and care is taken to keep them cool. Candy jars are
best, because the wide mouth allows the air free access to the water.
If enough sea water cannot be had to change that in the jars every
day, it may be aerated by pouring it back and forth a number of
16 Lessons in Zoology.

times in a current of air. Young anemones may sometimes be in-
duced to eat meat, drawing it into the mouth with their tentacles,
and will generally take the little crab found in the gills of oysters,
which they consider an especial dainty, but I have never been able
to tempt the older ones with anything. They will not expand well
unless kept in a cool, shady place, that shall at least remind them
of the tide-pools where they hide under the shadow of the rocks
and seaweed. If we try to handle them, as in taking them off the
rocks, they contract into little solid lumps (Fig. 3), with apps~-
ently neither mouth nor tentacles.

The children should examine them for several days, then bring
the results of their observations to the class, as was done with the
hydra,

The body is hollow and cyl-
inder-shaped, but very much
larger and broader than that

 

Fig. 3.

of the hydra. By the lower end it attaches itself to
some object, and the upper end is a broad disk with the
mouth in its center. The mouth seems to be an opening
produced by folding the skin inward. Around the mouth
are many rows of tentacles, which are finger-like projec-
tions from the body.

In the center is the stomach. Many partitions extend
inward from the body-wall, some of which join the stom-
ach and hold it in place, others reach only a part of the
way to the stomach. They are shown like the spokes of
a wheel in the cross-section given in Fig. 5, with the eggs
The Sea-Anemone. 17

attached to them. In very transparent anemones it can
be seen that the tentacles project over the spaces between
the partitions. The stomach is not simply a cavity hol-
lowed out in the body, as in the hydra, but is another hol-
low bag hanging down inside the outer one.

When very young the sea-anemone is
like the hydra, but as it grows, the
upper end of the body-tube folds inward
till it hangs down inside as an open sac,
about half as long asthe body. To illus-
trate this, take a glove-finger and cut
off the end to represent a hydra, then
turn in the end for some distance, and
the part hanging down inside will repre-
sent the stomach of the anemone. The
proboscis of the hydra and the stomach
of the sea-anemone are therefore precisely similar in their origin,
though different in their use; that is, they are homologous. While
digestion is going on, the lower end of the stomach is closed by
muscles, and refuse matter is afterward ejected through the mouth.

 

Fig. 5.

The tentacles are covered with lasso-cells, or thread-
cells, similar to those of the hydra. The white threads
thown out from tiny loop-holes in its sides when an anem-
one is disturbed, also bear myriads of these little weapons.

Sea-anemones are often produced from buds, which
form around the base of the old ones. If one is torn in
scraping it from the rocks, the portion left behind will
become a perfect animal.
CORALS.

Lesson I.

A single large specimen of Galaxea (Fig. 1) or some other coral
with large tubes, will furnish every child in a class with a tube for
study, while the teacher should have a piece consisting of three or
four tubes, and if possible, one or two smaller ones jast budding
out. Though Galaxea is best, still no teacher need omit the lesson,
if sbe can obtain pieces of the common madrepore or finger-coral
(Fig. 2). But if this is used, each child should have the end of
a branch showing the large polyp at the tip, and a group of little
ones around it. A living sea-anemone in the schoolroom will be
a great help. Blackboard drawinga of budding hydres should also
be kept for the Jesson.

  

Fie. 1.

The children have become familiar with the idea of the
skeleton in the sponge, so they at once see that coral is
only the skeleton of the coral animal, and that each tube
is made by one animal. They quickly make the follow-
ing observations :

It is white. It is shaped like a tube. It has lines on
the outside. It has little walls on the inside. It is hard
like stone.
Corals. 19

The teacher tells them that this is a stony coral, with a
skeleton made of lime. Then they look carefully at the
top and the sides of the skeleton, to see if it will remind
them of any animal they have studied, and find it is like
the sea-anemone.

Some pieces of Galaxea will show plainly that there are twelve
stony partitions that nearly meet in the center of the tube, and
twelve more that are shorter, but the specimens are often so broken
that it is difficult to tell how many of the partitions are long and
how many are short. It ia not best to have the children count them
unless the teacher knows from personal examination of the tubes
that her pupils can readily see how many little walls of each sort
there are.

After the question, How are these tubes held together ?
an examination of the teacher’s large specimen shows that
a stony, white, spongy substance connects them.

 

Fie. 4.

 

Fig. 3 has been put on the blackboard, drawn wholly in red, be-
cause it shows only the fleshy parts of the coral. This ia not the
Galaxea, but it bas the same kind of a stony skeleton, and the
same arrangement of all the fleshy parts. The children now de-
scribe this figure.

This new coral has a fleshy tube. It has a disk at the

top of the tube, with the mouth in the center. It has ten-
tacles around the mouth. There are little animals bud-
20 Lessons in Zodlogy.

ding from some of the tubes. There is flesh covering the
stony skeleton between the tubes.

It is easy now to understand that the spongy filling be-
tween the tubes of Galaxea is formed by the layer of flesh
that covers it, and connects the animals. A colony of
Galaxea is formed by the budding of young animals from
this connecting layer, around the base of the old ones.

Fig. 4 is a cross section of the body of a living coral, but does not
show the stomach. It represents what we should see if we were to
eut off the upper half of the tube and then look down upon what
was left. For the blackboard the unshaded parts should be drawn
in red, to represent flesh, and the shaded parts in white, for the
stony skeleton. The children now tell what they see in this figure :

There’s a tube of flesh outside of the tube of stone.
There are fleshy partitions and stony ones. The fleshy
partitions are in pairs, and the stony ones are not. There
are six pairs of long, fleshy partitions, and six pairs of
short ones. There are six long stony partitions, and six
short ones. There is a tube of flesh inside the stony tube,
and the fleshy partitions grow out from that.

The stony partitions are not formed by the fleshy ones, but grow in
folds of the fleshy tube, that arise from its base between the fleshy parti-
tions.

Lesson II.

The same specimens are needed as for the last lessun, with
finger-coral besides.

Review by asking what the coral has that the sea-
anemone has, then what the coral has that the sea-anemone
has not. This comparison will bring out from some
bright child the observation, ‘“‘ Why, the coral is just like
a little sea-anemone with a skeleton!” This is exactly
what we wish to find out, and the children will see it
Corals. 21

more clearly if there is still a little colony of very small
sea-anemones in the schoolroom.

Fig. 5 is a diagram to be drawn in red and white, showing the
upper half of the fleshy tube with the tentacles, and a cross-section
through the calcareous
tube with its partitions.
To make it plainer, only
six long and six short
partitions are shown,
and just as many tenta-
cles, each long tentacle
lying directly above a
long partition, and each
short tentacle above a ,
short one. This figure
not only shows the re-
semblance between the
coral animal and the
sea-anemone, and the re-
lations of the fleshy parts to the calcareous skeleton, but also the
manner in which the fleshy base of the tubes (b) extends from one
to another, thus binding together all the animals. It is this which
forms the spongy filling of lime (c) between the tubes, and from
which new tubes bud as the colony grows. A vertical section
through a large piece of Galaxea will often show that moat of the
polyps die at the end of each season ; but the next season those that
have lived spread out their fleshy bases and build a new spongy
layer of lime over the tops of the dead tubes below.

The children will have suspected by this time that the
stomach, the mouth, and the poisoned lines on the tenta-
cles of the coral are like those of the sea-apemone, as is
really the case.

   

The class is now ready for the finger-coral, and the teacher may
happen to have a piece that resembles a hand with fingers, thus
suggesting its name. The children’s observations follow :

It is white and stony. It grows in branches. It has
little bits of cups on the branches. It has very small
tubes. The tube at the end of the branch is much larger
22 Lessons in Zoology.

than the others. The large tube has partitions on the
inside and on the outside too, but the little tubes are only
rough. I think that is because the tubes are so small that
the partitions can’t grow very far. The smallest tubes of
all are close to the large tube at the end of the branch.
They look as if they had budded from the large tube.

Some of these observations must be drawn out by such questions
ag will readily occur to any teacher.

Now if a branch of the coral is broken and passed
around the class for the scholars to examine the broken
vuds, while one with an eye for beauty, may see
“something like lace with a star in the middle,” and
another only “a piece of stone with a little wheel in
it”; some one will finally discover that ‘the middle
of the branch looks like a cross section of a tube”
(Fig. 2a). In this way children can find out for them-
selves that the large tube at the end of a braneh, which
has kept on growing year after year, is the one from
which all the rest have budded. Great bushes of this
coral sometimes grow to the height of sixteen feet, so we
kuow that the parent polyp of each branch must live
to a great age.

The stony corals are the reef-builders, and a large part of every
coral reef consists of branches of madrepore beaten and pounded
by the waves into « mass of coral rock. These lessons on stony
corals may well be followed by an imaginary trip to the coral
islands for a geography lesson.
Corals. 23

Lesson ILI.

 

Fic. 6.

A whole sea-fan (Fig. 6) for the teacher, and small pieces for the
children, with the stony corals before used, are needed for this les-
son. These should be supplemented by a small piece of the precious
red coral, and by a blackboard drawing of Fig. 7 in colors. In this
red-coral the branches themselves, as well as the flesh covering
them, are red, while the separate polyps are white.

The name fan-coral, or sea-fan is quickly suggested
as the teacher’s large specimen is held up before the class,
after which pupils’ observations are in order :

My piece of sea-fan is yellow. Mine has dark edges.
Mine is made of a great many little branches, that join
together in a network. I can break off something like a
24 Lessons in Zoology.

yellow crast from the edges of mine, and there’s a little
dark brown wire left. I can see lots of little dots all over
mine. They look like pin-holes.

All are now interested to
learn that the “yellow crust ”
is the flesh that connected all
the animals of the colony, and
the “brown wire ”’ is the skel-
eton. The flesh contains so
many bits of lime that it be
comes hard when it dries, and
so remains on the stems. The
skeleton is horny. In order
to understand what the “ pin-
holes” are we must turn to
the diagram of the red coral (Fig. 7), which the children
describe :

There is red flesh between the coral animals. The
coral animals are white. They have only eight tentacles.
The tentacles are fringed. One of the coral animals has
drawn itself back into the red flesh, and only its tentacles
show. Two other coral animals have drawn themselves
all back into the red flesh, and there’s only a little bit of
white in a round, red place to show where they were.

It is now easy to see that the animals which make the
Galaxea and the finger-coral could not hide so nicely in
the flesh that covers the branch because the stony tubes
would be in the way, and to draw the conclusion that the
red coral has no separate tubes. Neither does the fan-
coral animal make tubes.

Skillful questions now lead the pupils to see that if the
red-coral animals die, and the flesh dries, a red stem
will be left with dried fiesh on it, and in the flesh little
holes that show where the animals were. So they know

 
Corals. 25

that the “ pin-holes” in the yellow flesh of the sea-fan
are the places where the living animals were.

The sea-fan and the red-coral, as well as the others studied, in-
crease by budding, but in all these, each separate colony starts
from a single egg.

 

  

Fia. 9.

The lesson ends with a comparison of the stony corals
and the sea-fan, which the children afterwards write out.
Fig. 8 representa a coral like the sea-fan in structure, in which

the branches do not interlace. Fig. 9 is the organ-pipe coral with
its green polyps expanded above the red tubes.
THE STAR- FISH.

Lesson I.

SPECIMENS: A dried star-fish and a single dried ray for each
child, and » few large astar-fishes in alcohol. The single rays
should be cut open down the back and the contents removed, leav-
ing only the sacs connecting with the tube-feet. The best way to
prepare star-fishes dry is to put them into fresh water until their
bodies become fully rounded, then to soak in alcohol for au hour or
two to harden the tissues, and finally to dry in the sun or a moder-
ately hot oven. If alcohol is too expensive, they may be put into
boiling water for a few minutes before drying. But the rays will
drop off if they are left in the hot water too long. In this lesson,
and the two following, parts are described as they appear on dried
specimens.

       
      
      

x

BS peeces

etn, '

pea e
sess

S28
RES

NRTA

Fee oe:
“o Sos

SI

5 See
ce o's,
SaD5,
BlEDOSe:
esas,

Fig. 1,
The Star - Fish. 27

Our new friend is called a star-fish, from its shape like
a star with five points, which we call rays or arms. Its
home is in the sea, on the piles of wharves, among the
rocks, or on oyster and mussel beds. In summer it is
often found above low-water mark in tide pools, but in
winter it takes refuge in deeper water. When dried it
gives us no idea of the rich colors,—red, bluish, green, or
brown,—with which it beautifies the sea-bottom. Unlike
most of the animals so far studied, it can move slowly
from place to place.

The children at once find the mouth, but we wish to
study the back tirst, “the side that is rough all over.”
(Fig. 1.) Holding this uppermost we find the sieve, a
round, coral-like spot that is red or orange when the star-
fish is alive, and used to filter the water that passes in
through it. The central part of the star-fish is the disk.
The sieve is on one side of the disk, near the angle where
two rays meet. If now a line is drawn from the sieve
across the disk and through the middle of the opposite
ray, there will be the same number of rays
on each side of the line, that is, the star-
fish will be divided in halves.

This gives us a hint of the bilateral symmetry
seen more perfectly in the higher forms.

The back of the star-fish is covered
with knobs,—“ prickers,” the children may
say,—called spines. They are short and

Fic. 2. rounded at the tip, and we find by trying
them on alcoholic specimens, that they do not move.
Between and around the spines are little things looking
like tiny grains of meal, which are two-pronged forks, or
pedicellariz (Fig. 2), always opening and shutting. We
do not know their use, unless it is to keep dirt from cling-
ing to the star-fish. On alcoholic specimens these will

 
28 Lessons in Zotlogy.

show beautifully in little circles around the spines.

Covering the star-fish we see the brown skin, and look-
ing on the inside of the back of the separate rays, we
find the beams of the skeleton, like little bones imbed-
ded in the flesh, making an irregular net- work.

Every one who has seen a living star-fish, has noticed the
difference between its rounded outline in the water and its flat-
tened appearance when thrown up on the
beach. This is because the skin of the
back is pushed ont into numerous tubes
like tiny glove-fingers (Fig. 3, d), so thin
and delicate that they fill with water and
again allow it to ooze out of them when
exposed to the air. These tubes, that
can scarcely be seen by the naked eye,
are really also a rudimentary sort of
gills, for through their thin walls oxygen
passes from the water into the body of the star-fish.

 

Fig. 3.

Lzsson II.

We now study the under or mouth side of the star-fish, Some of
the specimens will show the mouth as a large circular opening
with a membrane surrounding it; others will have a brown mass,
the dried stomach, filling the opening or protruding from it; and
still others may have it nearly hidden by ten long spines, two from
each ray, meeting over it like so many teeth.

The mouth with the long spines around it, the stomach
usually seen just inside it, and the brown suckers filling
the grooves in the rays (Fig. 4) first attract our attention.
The stomach can be protruded by means of muscles at-
tached to it. This is because our friend feeds on shell-
fish, working great havoc on the oyster and mussel beds.
It clasps an oyster with its rays, then turns out its stom-
ach, and proceeds to digest its victim at its leisure. A
star-fish will clean a shell in this way more perfectly
than it can be done by hand.
The Star- Fish. 29

The four rows of suckers in each ray are on the ends of
the tube-feet. In alcoholic specimens these completely fill
the grooves, and in life they even extend beyond. The
star-fish moves about very slowly, stretching
out one ray as far as possible in front, plant-
ing a few suckers at a time, drawing the
body up to them, then lifting them and tak-
ing a fresh start. The tube-feet at the tip of
each ray are extended in front as feelers.

Ths sieve on the back connects by a tube with
lime in ite walle, hence called the stone canal, with
a cucular canal around the mouth, from which a
tube extends down each ray. From these radial
tubes branches lead to each one of the small, muscu-
lar sacs (Fig. 3, g) seen on tha inside of the raya to
be connected with the tube-feet. These sacs and
some larger ones opening into the circular canal, act
as reservoirs for the water that enters at the sieve
and force it down into the tube-feet when the star-
fish moves. One can fully understand and appre-
ciate this water-system of the star-fish only by see-
ing it ina specimen in which the tubes have been injected with
Coloring matter.

 

Down the middle of each ray a brown line.—the radial
nerve (Fig. 3, /),—will be seen on most of the specimens
ending at the tip of the ray in aneye. In life the five
little red eyes filled the tiny hollows at the end of the rays.

The central part of the nervous system, as of the water-system,
is a cord around the mouth, occasionally seen on the dried animals.
The eyes of the star-fish see light only, as ours do when the lids are
closed.

The star-fish has also the sense of smell. After one
has been kept without food for several days, it can be led
around the tank after a piece of shell-fish held just in
front of it with a pair of forceps, precisely like a hungry
dog after a bone.
30 Lessons in Zoology.

Lesson III.

The hard parts of the back were noted.—tha spines, the forks,
and the beams of the skeleton,—now those of the mouth side are
to be examined.

On the cross-section of each ray (Fig. 1) may be seen
two rows of narrow plates (Fig. 3, a) forming the roof
of the groove, with small openings between them
through which the tube-feet pass. These are the per-
forated plates. On each side of these is a single row
of irregularly shaped, somewhat thickened plates (Fig.
3.5), called in distinction from the others, unperforated
plates. On the alcoholic specimens we observe that
the slender spines borne on these plates are movable,
the only movable ones, in fact, on the body of the star-
fish.

Inside the rays are the brown masses of the liver and the grape-
like clusters of the ovaries. The eggs pass out at minute openings,
difficult to find, in the angles of the rays.

Not only is the shape of the body radiate, but all the organs
show a radiate arrangement. From the central water-system run
five radial water-tubes; from the stomach a lobe to each ray ; liver-
lobes are found in each ; the oral nerve-cord sends out five
branches, and each ray ends in an eye. ‘The attention of the
class may be drawn to as many of these points as they have ob-
served, in order that they may get the idea of the symmetrical
arrangement of parts around the common center.

Some of the specimens will show the convenient power
that the star-fish has of replacing lost rays (Fig. 5). He
seems not to mind the loss of two, three, or even four, at
a time, and grows them again with wonderful rapidity,
More than this, if he is torn in pieces, and the parts
thrown into the sea, each ray will become a star-fish.
The Star- Fish. 31

This star fish with the round disk
and the snaky arms is the brittle-
star (Fig. 6). Though found in
abundance on our coast, he hides him-
self away under rocks and seaweeds,
so that he is rarely seen by most
people. “Catch me if you can,” he
seems to say, for not only does he
wriggle away at a speed that is the
greatest contrast to the snail’s pace of
the common star-fish, but if we do
seize one long ray, he coolly drops it
off, and disappears with the other
four. Often the only way to secure
a perfect one is by dipping it up in
a quantity of water with the sea-
weed on which it lies.

 

 

Fie. 6

The rays of the brittle-star are solid, the ambulacral plates,—
which correspond to the perforated plates of the star-fish,—being
on the inside and covered by row of extra plates, ao that the
organs of the body must needs be all in the disk. Though his
32 Lessons in Zovlogy.

tube-feet end in points, he does not miss the suckers, but moves
about by means of his long, muscular raya. In order to move
rapidly he uses two of his opposite arms with a motion like swim-
ming, leaping about two inches at each stroke.

A small, beautifully colored star-fish, also found on the New
England coast, has five tapering rays with only two rows of tube-
feet on each. This species carries its eggs around the mouth.

The common star-fish south of Long Island Sound is green or
brown, the one usually found north of that sound is red or purple.
THE SEA -URCHIN.

Lesson I.

Not the little ones usually seen on the shore after a storm or in
the tide-pools, but large ones that have been taken from their
hiding places under stones below low-water mark. The best prep-
arations for study are made by drying them with the spines on, and
then sawing them in two horizontally. Besides these every shell
and piece of a shell without the spines will be of use. Perfectly
bleached shells are often cast up on the shore by the waves, but if
enough of these cannot be found, the spines may be removed by
placing them for a time in a dilute solution of potash, then clean-
ing them with w tooth-brush. Care must be taken not to leave
them in the potash too long, or it will cause the plates to drop
apart. It will add greatly to the lesson if the teacher can also have
a few large sea-urchins in alcohol, and a Mediterranean Echinus,
or sea-egg, either with or without the spines.

The sea-urchin (Fig 1) is also sometimes called the
sea-egg. It is a green or purple ball. -It is not a perfect
ball, but flattened on both sides, more so on the mouth
side than on the back. It is bristling all over like a
small hedgehog with spines longer than those of the
star-fish.

We try the spines on the alcoholic specimens and find them
movable. They are held to the shell by tiny muscles, We care-
fully pull off a large spine, and see the knob upon the shell and
the socket in the base of the spine that fits over the knob, thus
making a ball-and-socket joint.

We know the mouth on the under side (Fig. 2) by its
little star made of the five white teeth. Though the
teeth appear small when seen from the outside, on exam.
ining them from the inside we find that with the jaws
34 Lessons in Zovdlogy

and muscles attached to them they form a powerful ap-
paratus called the lantern. Invide the shel’s from which
the lantern has been removed, can be seen five projections
to which some of these muscles were attached. With its
teeth, which are constantly growing at the root as they
are worn away at the tip, the sea-urchin scrapes seaweeds
off the rocks, as it walks about mouth downward, and it
also feeds upon dead fish.

 

Fie. 1.

The sea-urchin walks with tube-feet, as the star-fish
does, but its suckers are smaller and more nearly the
color of the spines. If we have only dried specimens, in
order to see the tube-feet we must look steadily and pa-
tiently on the under side of the shell. Children will see,
after a little thought, that they are largest on this side
because they are used most in walking. But how can the
The Sea- Urchin. 35

sea-urchin walk on the suckers, while the spines reach out
so far beyond them? To understand this and to know
how beautiful the little creature really is, we ought to
have a living one in a glas; dish or jar of sea water, and
watch it press out its tube-feet tili they are waving on
every side, far beyond the spines, like threads of spun

 

glass. It stretches them out to their fullest extent, fast-
ens the suckers, then pulls the body up to them. We
touch it, and instantly every one is drawn safely in be-
hind the barrier of sentinel spines.

Since the tube-feet of the sea-urchin are forced out in
the same way as those of the star-fish, we see the need of
a sieve to filter the water that does this work. We find
it, a five-sided, spongy body (Fig. 3, a), at one side of
the little disk in the center of the back.
36 Lessons in Zoélogy.

Lesson II.

In the last lesson we have examined the spines, have found the
mouth with its lantern, the tube-feet and the sieve, and have learned
how the tube-feet can be extended beyond the spines. We begin
with a review of these points.

The spines protect the sea-urchin against its enemies,
and are sometimes used in walking. If one is taken out
of the water and put on a table, it will try to walk on its
spines.

Some species habitually use the spines in this way. A pentago-
nal gea-urchin that lives on coral reefs, covers itself with bits of
seaweed and pebbles, holding them on with its tube-feet, so that

but little of its body is exposed, while walking on its spines. Our
common sea-urchin often hides under a covering of sand and grave'.

On alcoholic specimens, and on the under side of large,
well-preserved dried ones, children will see that the tube-
feet are arranged in five double rows, and later in the
lesson will connect this fact with the arrangement of the
plates of the shell. The forks can be best seen on the
disk of tough skin around the mouth, where they form a
circle. They are larger than those of the star-fish, three-
pronged, and mounted on handles (Fig. 4). They are

scattered everywhere among

the spines, but largest around

the mouth. It has been

found by experiment that
oes they will grasp a frond of
seaweed. waving lightly over them in the water, and hold
it like so many tiny forceps till the suckers have had time
to fix themselves upon it.

The remainder of this Jesson is the most difficult part of the

work on the sea-urchin, and should be conducted by the teacher
with the greatest patience and care. Though “ Make baste slowly”
The Sea- Urchin. 37

should always be the motto in science lessons, any attempt at haste
will be especially fatal here.

Taking the bare shells we first see that they are com-
posed of many parts called plates. As we hold them up
to the light and look inside, we discover a great many
small openings in them, like fine pin-holes. There are
ten rows of these openings, or five double rows, and sharp
eyes will see that there are also five double rows of small
plates through which these holes pass. These are the
perforated plates, and the holes are for the tube-feet, as
in the star-fish. On each side of a double row of small
plates is a double row of large plates without openings.
These we call the unperforated plates, and we find five
double rows of these also. We remember that there are
ten rows of perforated plates in the star-fish, also, as well
as ten rows of unperforated plates.

We now find an opening in the sieve, and we observe
that the sieve is at the end of two rows of large plates.
From the inside of the shell four more openings can be
seen at the end of the other double rows of large plates.
These are the openings through which the eggs pass out
into the water. The egg-openings are in little plates
shaped somewhat like the sieve, and really five in number
since the sieve is on one of them.

Five more tiny holes alternate with the egg-openings,
and stand at the end of every two rows of perforated
plates. These are eye-openings, and are in very small
plates called eye-plates. The young sea-urchin has five
eyes in these places, but when fully grown he has only
these orifices, through each of which a tube-foot passes
out. Inside the circle of eye-plates and egg-plates is a
little disk of tough skin containing minute plates.
38 Lessons in Zoilogy.

Both egg-plates and eye-plates are difficult to make out clearly,
except on large specimens of the common sea-egg, but both
are shown beautifully on the large Mediterranean sea-urchin.

Each child should now draw such a section of the
shell as is represented in Fig. 3, consisting of two rows
of perforated plates with one row of large plates on each
side of them, and the central disk surrounded by its
circle of plates.

Lesson ITI.

When we go to the seashore, where shall we look for
star-fishes ?

In tide-pools. On the rocks under water. On oyster
and mussel beds.

Where shall we find sea-urchins ?

In tide-pools. On rocks under water. Sometimes
hidden under stones and gravel in the water.

What did we find on the star-fish ?

Short spines. A sieve. Tube-feet. A mouth. Five
eyes. Five nerves. Tiny specks of forks.

What have we found on the sea-urchin ?

Long spines that will move. Tube-feet. A sieve. A
lantern. Five teeth. Lots of forks with handles. Five
holes where the sea-urchin had eyes when it was young.
Rows of small plates with holes in them. Rows of large
plates.

How many rows of each?
Ten rows of each.
The Sea- Urchin. 39

What plates did we find on the star-fish ?

Plates that made a network on the back. Two rows
of perforated plates on each arm. One row of unper-
forated plates on each side of the perforated ones.

What is the use of the holes between the perforated
plates of the star-fish ?
The tube-feet pass through them.

How are the rows of plates arranged in the sea-urchin ?

First there are two rows of large plates, then two rows
of small plates.

How many rows in all?

Ten rows of each kind.

Where are the eye-openings ?

At the end of the rows of small plates. At the end of
the perforated plates. At the end of the plates that the
tube-feet come out through.

Where are the eyes of the star-fish ?
At the point of each ray.

Are they at the end of any rows of plates ?
Yes, at the end of the rows of perforated plates.

And where are they in the sea-urchin ?
At the end of the rows of perforated plates, too.

Where are the egg-openings ?
At the end of the rows of large plates.

But we have not found any nerves, some child suggests.
No ; for the sea-urchin has them safely tucked away on
the inside of its shell.
40 Lessons in Zodlogy.

Fig. 5 is a diagram rep:esenting a cat through a sea-urchin; s is
the sieve, or madceporic body, and c the tube leading from it to the
ring around the mouth, from which
branch the five radial water-tubes
(f). Hach of these radial water-
tubes connects with the sacs (g) of
the tube-feet and ends in a single
tube-foot (x), which passes out
through an eye-opening. The black
line outside of f is a radial nerve,
also continuous with a cord around
the mouth. The cut ends of the
intestine are seen at k: the ovaries
at/; the branchial tufts at m; ath,
the teeth; and at z, some of the Fia. 5.
muscles that move the jaws; bisa
spine; e, a plate of the shell; and n, one of the forks, or pedi-
cellariz.

 

If any of the children have sand-dollars (Fig. 6) or
sand-cakes, as they are
often called, they will be
delighted to discover that
they are simply flattened
sea-urchins. Perfect ones
are very pretty, with their
mouse-colored covering of
tiny spines, and the bare
shells show the different
rows of plates and the
mouth on the under side.
The tube-feet project from
perforated plates, and form the beautiful star on the back
by expanding into gill-like appendages. This sea-urchin
lives partly buried in the wet sand of our shores and of
the shallow waters.

 
THE CLAM.

Lesson I.

The common soft-shelled clam of the New England coast (Fig.
1) is the one chosen for these lessons, but the fresh-water clam
found everywhere inland can be used equally well. Large ones
should be obtained, and if kept alive in the schoolroom ia a jar of
sea-water for a few days before the lesson, the children’s observa-
tions will form an excellent preparation for class study. The long,
dark siphon, often incorrectly called the head, will be extended
with the two fringed openings plainly showing, but will be at once
drawn in if the shell is touched. If some very finely powdered in-

 

Fig. 1.

digo is dropped into the water, the particles will enter at the lower
opening and pass out at the upper one. It will be seen that the
valves of the shell are connected by a dark skin that passes from
one tu the other, and is unbroken except by an opening near the
broad end of the shell, where the foot is protruded. If a living
fresh-water clam is kept in a jar with two or three inches of sand
in the bottom, it will assume its natural position, with its foot ex-
tended and its body partly buried in the sand (Fig. 2). With
this form particles of indigo can be even more plainly seen passing
in and out of the large siphonal openings.

If the clams are killed by putting them into warm water the day
before the lesson, the soft parts can easily be removed without
breaking the ligament at the hirge, while the two valves are still
42 Lessons in Zoology.

held together. The shells thus prepared can be put into the hands
of young children, who can afterwards see the principal soft parts,
such as the manile, the gills, and the foot, from the teacher’s
specimen.

The clam shell consists of two valves, which are con-
vex on one Jong edge and nearly straight on the other,
and which meet at a ‘“‘rounded point,” called the beak.
It is broad at one end and narrower at the other, but
both valves are alike in size and shape. To find the
right and left valves we hold the shell with the beak up-
permost and the narrow end pointing toward us, when
the right valve will be on our own right side, and the
left valve on our left.

The surface of the valves is not smooth, but roughened
by many curved lines. Beginning at the beak and
tracing all the lines between this point and the convex
edge of the shell, we find that they all start at the upper
side of a valve and pass around to the upper side again.
Children will quickly see that the baby clam could have
had but few of these lines, and that more have been
added as it grew, hence these are lines of growth. Now
they will be interested in tracing these back from the
outer edge to the beak, and seeing that this is the shell
of the baby clam and the oldest part of the whole shell.
A brown, horny skin covers the lower part of the valves,
but is worn away near the beak.

A few of the thickest shells have been roasted on a bed of glow-
ing coals, and pieces of them are now distributed to the class.

The roasted shells are white and crumble easily. The
lines of growth are the edges of layers of lime, which
can now be peeled off. The shells are not so heavy as
they were before.

Since the shells weigh less after the roasting, it ia evident that
some part of them has been burned away. To discover what was
The Clam. 43

lost, we suspend one or two shells in a dilute solution of acetic,
or hydrochloric acid, which will remove the lime.

The valves are held together by a hinge at the beak.
On the inside of the hinge is a brown, horny substance,
the ligament. By slowly opening and closing the shell
several times, we discover that the ligament (Fig. 3, 2) is

AL

[aI

Fic. 2. FIG. 3.

compressed when the shell is closed (Fig. 3), but, being
elastic, it forces the valves apart when the pressure ia
removed. On the left valve is a small shell-like tooth,
and a corresponding socket on the right one.

The class now draw the outside of one valve, writing on the
drawing the names of all the parts they have seen.

Fig. 3, section through a clam-sbell; /, the ligament; m, one of
the muscles that draw the valves together.

Lesson II.

Jn addition to the shella already studied, children who are old
enough may have freshly killed clams in which only the adductor
muscles have been cut. Specimens put into warm water the day
before the lesson, will die with siphon extended. The teacher
needs also a living clam.

We first examine the shells that were left in dilute acid :

These shells are soft. They will bend easily. There
is no lime in them, but they seem to be made of flesh.
Clam shells are made of layers of flesh and layers of lime.

We remove the left valve now and examine the inside :
44 Lessons in Zoology.

It is whiter and smoother than the outside. It has a
line around it near the edge. It has a broad mark near
the narrow end and another near the broad end of the
valve (Fig. 4). It has a deep curve between the line and
one broad mark.

One child takes the living clam and finds he cannot
open its valves. The teacher then holds up a dead clam
in which the muscles have not been cut, and after care-
fully pushing back the fleshy bag that adheres closely to
the edges of the shell, she severs both muscles. The
children see that when they are cut, the valves come apart
everywhere, except at the beak. One child now lays the
valve back over the body of
the clam, and finds that the
two broad marks on the inside
(Fig. 1, aa and pa) exactly
cover two firm, white organs,
which are the muscles that held
the valves together. In this nes
way see that the marks are the impressions of the
muscles, and were made by them.

The same process shows us that the line near the edge
was made by the thick, muscular part of the fleshy bag,
or mantle, that covers the clam, while the deep curve, or
sinus (Fig. 4), is the impression of the siphon muscles.

We have noticed that the dark skin covering the mar-
gins of the shell, seems to be connected with the mantle,
and, indeed, it is formed by the mantle border. This
same border of the clam’s cloak is a hard worker, con-
stantly laying down new deposits of lime around the edges
of the shell. The mantle is closed except at the siphon
and the foot openings.

After finding the little furrow in the lower edge of the
mantle and cutting through it from the siphon to the for-

 
The Clam. 45

ward end of the shell, we lay the mantle back, as repre-
sented in Figure 5. Just under the mantle lie two of the
gills (Fig. 5, a), two delicate, fluted ruffles, and on the
opposite side of the body are two more. At the forward
end of the body are two pairs of delicate flaps, the palpi
(Fig. 5, p), and be-
tween these is the
mouth (m). The
foot (f) is a curious
little lump of mus-
cle, easily found,
because there is but
one. Now we see how the clam can burrow in the mud,
and why he needs such a Jong siphon to reach up to the
water, while he is snugly hidden in his hole.

 

Fig 5.

So much the youngest children can see from the teacher’s spec-
imen. They should now draw the inside of one valve, and mark
on it the position of the gills, the siphon, the foot, and the mouth,
as well as the impressions on the shell. If there is time, older chil-
dren, each with a clam in a small dish of water, can go further.

A probe passed into the lower opening of the siphon, enters the
body cavity just below the gills. Water coming in at this tube is
strained by the waving hairs on the gills, then passes through the
gills, giving up its oxygen to the blood on the way, and out by the
upper tube of the siphon. At the same time by the motion of the
hairs, or cilia, tiny plants and animals in the water are gathered
into threads and swept down to a channel on the lower edge of the
gills, along which they move forward to the mouth. By lifting
the palpi a probe can be passed into the mouth.

To see the heart, cut away the mantle from the top of the gills,
being very careful not to cut anything else. Ina little cavity just
behind the beak lies the heart, with the dark tube of the intestine
passing through the ventricle. The somewhat fan-shaped auricles,
one on each side of the ventricle, are not easily found except by one
skilled in dissection.

To he seen distinctly, all these fleshy parts must be floated out
under water.
46 Lessons in Zoblogy.

Lesson III.

The last two lessons should be thoroughly reviewed by the aid of
the shells and a blackboard sketch on which the organs can be
located ag they are described by the children.

It will add interest to the talk about the burrowing habits of the
clam, if the teacher can show
a razor-shell (Fig. 6), and
explain that this kind of clam

Fia. 6. burrows so fast with its pew-
erful foot that one can head it off only by = sudden oblique cut
with the spade.

South of New York the
round clam, or quahog
(Fig. 7), is the common
one in the market, and
will be the most conven-
ient type for these les-
sons. On sandy shores \
this burrows but little be-
low the surface, often even
crawling about with its
shell partly exposed. This habit is the explanation of the short
siphon tubes. It is taken in muddy creeks by long tongs or rakes.

 

 

The large, rounded shell of this clam, with its prom-
inent beak, has the hinge ligament on the outside. Chil-
dren will see, by carefully opening and shutting it, that
the ligament is stretched when the shell is closed, and so
opens the shell when it contracts to its natural size.

The foot and mantle edges are white, the siphon tubes
yellowish or brownish orange, mottled toward the end with
dark brown or opaque white, and are separated a little at
the end. The mantle lobes are separate and ruffled at
the edges. The elam easily burrows when necessary, by
means of its large foot with a broad, thin edge, which can
The Clam. 47

be protruded from any part of the lower side through the
large opening in the mantle.

In many parts of the country the fresh-water clam will be the one
moat easily obtained. The manner of keeping it in the schoolroom
has already been described.

A horny brown skin sometimes covers the whole shell
of the fresh-water clam, but is usually worn off near the
beak by the action of acids in the water.

Fig. 2 shows the position of one of these clams in crawling, the
line at s representing the bottom of a lake or river, above which ia

water.

The beak is far forward, and the long hinge ligament,
being on the outside, acts as in the quahog, like a spring
to open the shell. On the inside of the shell are several

 

FIG. 8

hinge-teeth, if the clam is a Unio, generally two wedge-
shaped teeth on the left valve and one on the right, while
back of these the right valve bears one long lateral tooth
and the left bears two.

In Fig. 8 two of the wedge-shaped, or cardinal teeth are shown
on a right valve at c, and the lateral tooth at /.

The pearly lining of this shell is the same as that which
forms the mother-of-pearl of the pearl oyster. When this
deposit is increased by a particle of sand or some small
object that has worked its way in between the mantle and
the shell, an imperfect pearl is formed. Since the clam
48 Lessons in Zodlogy.

cannot expel an intruder, he takes this way of covering it
up and thus freeing himself from the irritation it caused.

Near the impressions of the adductor muscles (Fig. 8,
aa and pa) are two smaller prints (ap and pp) made by
the muscles which move the foot. The pallial line (p)
runs from the anterior to the posterior adductor, but with-
out any sinus. This lack is explained when we see that
this clam, the back part of whose body is never buried in
the sand, has no long, muscular siphon, because it need«
none. The mantle, open everywhere else, is simply united
enough at the siphon to make two very short tubes, which
are always in the water.

The parts of the body have the same relative position asin the

salt-water clam, but the palpi, instead of hanging freely, are simple
folds.
THE OYSTER.

Lesson I.

Our oysters, which are the largest ones to be had, will need at
least twenty-four hours in warm water to kill them, even if a hole
large enough to admit the water has been nicked in the edge of
each one. They are sponged to remove the dirt, without taking
off the brown skin. Roasted and decalcified shells are on hand, too,
to show the layers of lime and flesh. Before the lesson, the large
muscle should be cut between the lower valve and the body of the
oyster. If we remove the lower valve, the knife will follow the
eurve of the shell, and will not be so likely to injure the soft parts.
The teacher has an oyster with the muscle still uncut.

The oyster shell has two valves, one larger and thicker
than the other. It is convex on one long edge, and con-
cave or nearly straight on the other. It is broad at one
end, and the beak is at the opposite narrow end. The
deposits of lime are much more uneven than on the clam
shell, and the shell is strongly roughened along the lines
of growth. One shell has a pieee of rock on the thick
valve, another has a young oyster fastened to it, and a
third has a piece split off from its large valve. These teach
us that the oyster was attached to some object by the
large, thick valve, which is therefore the lower valve.
The upper valve is smaller and thinner than the lower
one. To find the right and left valves, after holding a
clam shell in the proper position, we hold the oyster shell
in the same way, with the beak pointing away from us
and the concave side uppermost. Then the right valve
is on our right side, and the left valve on our left.

Various substances are found on the outside of the shell. Some-
thing red proves to bea bit of red sponge. Twisted white tubes
50 Lessons in Zotlogy.

were made by tabe-building worms. Some little mats with pin-
holes in them are the skeletons of tiny creatures, one of which lived
in each hole, or cell. Finally, some of the shells have been par-
tially riddled by the boring sponge, which makes its tunnels by dis-
solving away the lime.

The teacher now cuts the muscle in her oyster, and as the chil-
dren follow the course of the knife in her hand, they see that there
is but one muscle, and that after cutting that, the shell may be
opened by breaking the ligament.

The hinge is not exactly at the beak, but a little dis-
tance from it, and between the two is a widening groove
containing some dried remains
of ligament (Fig. 1, 27). In
the young oyster the valves
must have been united at the
beak, so the groove is the
downward path of the liga-
ment, as the oyster grew. The
inside of the valve is white.
There is a large, dark impres-
sion near the center of the valve. A line extends nearly
aroand the shell, not far from the margin. This is the
pallial line. By laying the valve back over the oyster
we see that the large dark spot fits over tbe muscle, and
hence is the muscle scar.

 

Fig. 1.

This scar bas also traveled downward from the beak. To show
this, file the outside of the thick valve to some depth, and strike
it sharply with a hammer, wben the inner layers of the shell will
split off, disclosing the track of the muscle.

The oyster has a mantle that is open all around. The
mantle is only a little thickened at the edges. The edges
of the mantle are joined together in just one place, the
bar (Fig. 1, 6), where the convex and the concave sides of
the shell meet. In front of the muscle is a clear space con
taining the heart (Fig. 1, 2), a little whitish bag. Under
the edge of the mantle are the gills, two pairs, as in the
The Oyster. 51

clam. Near the beak on the convex side of the shell are
the two pairs of palpi, and between them the mouth
(Fig.1, m).

Lesson IT.

This lesson, which is mainly a review, may be given with the aid
of the shella, according to the following outline :

Tell me some things about the oyster shell.

It has two valves. One valve is large and convex, the
other is smaller and flat. The large valve was fastened
to a rock. The shell is broad at one end and pointed at
the other. The pointed end is called the beak. The
outside of the shell is very rough, and the lines of growth
show very plainly. There is a hinge not far from the
beak, and a brown ligament.

What can you tell about the inside of the shell ?

The inside of the shell is nearly smooth. It is white.
or yellowish. Near the middle is a large dark place’
made by the muscle. There iz a pallial line near the
edge.

The shape of the gills and the palpi may also sometimes be seen
on the inside of the shell.

In what ways are the oyster shell and the clam shell
alike ?

Each has two valves. They have each a hinge and a
ligament. Each has a beak. They have a pallial line.
Each has a brown skin and lines of growth on the out-
side. They are made of layers of lime and flesh.

In what ways are they unlike?

The clam shell is smoother than the oyster shell. The
oyster shell has the beak at one end, the clam shell has it
ontop. The clam shell has both valves of the same size,
but the oyster has one large valve and one small one.
52 Lessons in Zvdlogy.

If the children are old enough, they may now be led to see that
while the left side of the mantle of the oyster can work steadily at
shell-building, the right side is constantly interrupted in its work by
the opening and closing of the valves, and that this accounts for
the small size of the right valve.

Tell me in what ways the soft parts of the oyster are
like those of the clam.

They have each a mantle and two pairs of gills. They
have a mouth and two pairs of palpi. They have a heart.

Tell me some things that are unlike in the soft parts.

The oyster’s mantle is open, and the clam’s is closed.
The oyster has one muscle, and the clam has two. The
oyster’s heart is close to the muscle, and the clam’s is
under the beak. I don’t see why the oyster hasn’t any
foot nor any siphon ?

 

Fig, 2.

Where dves the clam live ?

He buries himself in the mud. He digs down into the
mud with his foot

What use has he for his siphon ?

He reaches up to the water with it.

Where does the oyster live ?

He fastens himself to arock. I see; he doesn’t need
a foot because he doesn’t dig in the mud, and he doesn’t
need a siphon because his whole shell is in the water.

Oysters naturally live on rocks or hard substances (Fig. 2),
and after the young ones swim about for a while, they die if
they cannot find something hard to grow on, but they fatten
The Oyster. 53

better for the market on muddy bottoms, where there are
great quantities of tiny plants for their food. So when
they are half grown, the oystermen take them up and
“plant” them on the mud in some warm bay or at the
mouth of a river, where they are left for a year or two.
But they never dig in the mud, and so need neither foot
nor siphon.

I should think the currents of water would get mixed
if there isn’t any sipkon.

Is there any place where the edges of the mantle are
joined together ?

Yes, at the bar.

Then what is the use of the bar?

To separate the two currents of water.

One current flows in under the convex border of the mantle,
passing over and through the gills, and carrying food to the mouth,

the other flows ont on the opposite side of the bar, as indicated by
the arrows in Fig. 1.

As in the case of the clam and oyster, so with other mollusks the
presence or absence of the foot and siphon is a sure guide to the
habits of the animal.
THE SNAIL.

Lzsson I.

The French edible snail is the one we use if we can get it, but a
leason can be given on any good-sized land or water snail. The
alug (Fig. 1), which is simply a snail without any external shell,

 

Fic. 1.

ean be obtained at any season, it is said, by setting a trap for it in
a greenhouse. The trap is a box of moist bran, which will attract
it as cheese allures mice. But the slug is so likely to be repulsive
to pupils that it is much better to collect snaila in the summer and
keep them in flower-pots or boxes of earth covered with moss to
retain the moisture. If kept in « cool place, they will hide away
under the moss, close up their shells with a layer of mucus, and
sleep comfortably through the winter. If any of them come out
occasionally on warm daya, they will like to be fed with some wet
bran or Iodian meal. When they are active, the box should be
covered with a wire netting to prevent their escape from such
narrow quarters. A large colony has been kept in this way for
more than a year, fed during the summer upon lettuce, of which
they are very fond.

Tf the lesson is given in the winter and the snails have been kept
in a cool place, the shells will be closed with a layer of mucus, and
we can study them before the snails come out.

The shape of the shell reminds us of ‘a horn curled
up.” It has often made five or six turns in coiling, and
each turn is called a whorl (Fig. 2). The whorls together
form the spire, and the lines between the whorls are the
satures. From the opening, or aperture, we trace the

whorls up to the apex, where we find the little bag-like
The Snail. 55

shell that covered the baby snail. Then we follow the
whorls from the apex to the aperture, and watch them
grow larger at every turn. We remember the lines of
growth on the clam and oyster shells, and decide that the
delicate lines running parallel with the edge of the aper-
ture must be the snail’s lines of growth.

ERTURE

AP.

  

Fig. 3 shows how a shell grows, A isa young shell; B, the
same, fully grown; and C' is the same as B, but with the lines of
growth represented on it. The dotted lines on C show the way in
which it grows, a representing the first added layer, b the second,
and c the appearance of the shell when another half-whorl bas
been formed. Some of our shells have a Jayer of thin and very
Seed shell around the aperture, evidently jast formed and not yet

ardened.

Some snails’ eggs, or very young snails, will add interest to this
part of the lesson. In spring and summer the eggs of the pond
snail may be found on the under surface of the leaves of water-
plants in masses of jelly, in which the eggs look like little dots.
These will soon hatch out, if kept in a jar of water. The shells of
young snails are transparent, and the growth of the body and the
gradual coiling of the shell can be easily watched.

Holding the shell in the hand with the opening toward
us and the apex uppermost, the aperture is toward the
right hand. It is usually on the right, so when we find
one on the left, we will be careful to keep the shell.

Our snails have closed up the aperture of their shells
56 Lessons in Zoilogy.

by making a door of the mucus, or slime, that comes
from their foot. Every year when cold weather comes,
the land snails hide away under the roots of a tree, or
under a log or stone, and make this door to shut them-
selves in. Most of the water snails have a door all the
time, which they can shut whenever they please.

Lesson II.

Just before the lesson we drop our enails into a bowl of warm
water, and they are soon coming out, foot foremost.

Holding them upside down, we see a fleshy rim around
the aperture. This is the mantle, which builds the shell.
Just under the edge of
the shell is the breathing-
hole (Fig. 4, 6), which
keeps opening and shut-
ting, and leads into the
snail’s simple lung, only
a sac in the mantle with
blood-vessels in its sides.
The breathing-hole is on
the right side when the
aperture points toward the right, and on the left when
that points to the left.

Two pairs of horns, that are gradually pushed out, are
the tentacles (Fig. 4, s¢ and7z). The long tentacles are
the eyestalks ; the others are used only as feelers. We
touch a long tentacle, and a black thread pulls the eye
down inside. The black thread is the lining of the ten-
tacle, which contains muscles that draw the end in just as
we turn the finger of a glove when we pull it off in a
hurry.

The snail moves on its broad foot, and by putting it on

 
The Snail. 57

a piece of glass we see that the foot is a large sucker that
moves in little waves. The glass is soon covered with
slime, poured out of a very
small opening in the bottom
of the foot near the head. In
this way the snail coats bits of
earth and stone with a smooth

ci

Fig. 5. Fia. 6.

 

glaze, that prevents them from irritating its soft foot.

Finally, we feed the snails, and watch the hard brown
jaw (Fig. 5) as it bites off pieces of the young leaves of
cabbage, lettuce, or celery.

 

Fie. 7.

These pieces are chewed by the teeth on the anail’s tongue, which
point backward when the tongue is drawn in, but are made to
stand erect when the snail is eatiog and the tongue is pulled for-
ward by muscles. As the tongue works backward and forward,
the teeth grind the food against the hard jaw, and also the carti-
lage that lines the upper part and sides of the mouth. As many
of these tiny teeth are worn out every time that the snail eats,
pew oneg are continually growing in a little pocket behind the
tongue and pushing forward to take the place of the old ones.

Tf snails and slugs are troublesome in gardens, they
may be killed by sprinkling dust or ashes wherever they
58 Lessons in Zodiogy.

are. They throw out so much mucus in their efforts to
= remove the dry particles that
they soon exbaust their strength
and die of weakness. In Eu-

  

biG. 8 Fie. 9.

repe, where they do so much mischief in the vineyards,
the people take their revenge by eating them in turn.

P.. d.onsila have but one pair of tentacles, at the base of which
are the eyes. Some of them, like
the one seen in Fig. 6, have a
horny scale, or operculum, which
closes the aperture of their shells,
and the mouth on the end of a
rostrum, or beak, and also breathe
by gille. Others (Fig. '7) have no
operculum and ‘no rostrum, and
are air- breathers.

At the seashore we shall find the
large Lunatia (Fig. 8). Fig. 9
shows this as it crawls about partly
buried in the sand, with its broad foot extended and the shell
almost covered by the
soft body. With the
teeth on its tongue
(Fig. 10) it drilla into
the shells of other mol-

luske and eats out their
bodies through the
hole. This snail laya
its eggsin the ‘‘ sand
collars’? (Fig. 11) we have so often picked vp on the beach, the
round spots on them being egg-cases, and each one containing
several eggs.

 

Fig. 10.

 

FIG. 11.
THE EARTHWORM.

To rouse herself to the proper pitch of enthusiasm on this sub-

ject, the teacher has only to read Darwin’s Vege-
table Mould and EHarthworms. The moat inveterate
prejudice against everything that crawls will be
unable to survive a careful study of this book.

Oar living earthworms are kept for winter study
ia a box of earth in the cellar, covered to prevent
their escape, but not so closely as to exclude the
air. The earth must be kept damp, as worms
breathe only through the skin, which must there-
fore be always moist. Occasionally they will need:
a few leaves for food, which will disappear by
degrees inside their burrows. At night, when the
worms are busy foraging, if we remove the cover
quietly, and are careful not to let the light fall
directly on them, we can surprise quite an active
colony, each one exploring the earth around him
with the forward end of the body, while the tail
still clings just inside the burrow.

For our lesson each child has a living earth-
worm in a little disb. Half of the dishes are filled
with water, half with earth. A little talk about
the habits of the worms occupies a few minutes,
and gives the children time to become accustomed
to their movements and ready to observe them.

At first both ends of the long, ringed
body look alike to us, but by degrees we
discover that the end which always moves
forward (Fig. 1,21) is pointed and termi-
nates in a little knob, the upper lip. There

Fig. 1.

 

ae4S

 

 

 

 

 

 

Ve Zt

Cee

 

S.

 

=<

 

 

SLUGUULETT

 

LAS

 

 

 

 

ven
69 The Earthworm.

is no distinct head, but the mouth is at thig end. Here,
too, are the largest rings. The other end, or tail (Fig.
1. 2 2), consists of smaller rings, and is flattened at the tip
(Fig. 1,w). About one third of the distance from the
head to the tail is the saddle (Fig. 1, »), where the rings
are thickened and show much less plainly.

We can count the rings on an alcobolic specimen, but we must
remember that the surface of each ring is divided by a skin fold,
au that there are only half as many rings as folds. Exteading in-
ward to the intestine are muscular partitions which separate the
rings and divide the body into a series of chambers,

In color the worm is reddish brown, the upper side
being much darker than the lower. At first we think it
has no skeleton, but if we put an alcoholic specimen in
water for a few hours, we can remove a thin, horny
cuticle, or outer layer of the skin. Sometimes we detect
a beautiful iridescence, caused by the play of light on the
tiny folds of the cuticle.

Now, taking the head end of the worm gently between
the fingers, and holding it up, we shall see it open its
mouth in its efforts to escape, and thrust’ out a large,
white, membranous pouch, into which the mouth leads.
This pouch is drawn forward when the worm is digging
its burrow, thus swelling out the head and making a much
larger opening in the soil. As we hold the worm, we
feel the pressure of the stiff hairs, or bristles, on its
sides, which we see as bright points when it draws up its
rings and pushes against our fingers. There are two
double rows of these hook-like bristles (Fig. 1, s) on each
side of the body, just where the darker color of the back
joins the lighter color of the under side.

Earthworms have no teeth, but with their lips they pinch off the
soft parts of decaying leaves, on which they feed. The red thread
along the worm’s back is the principal blood-vessel. The dark
tabe passing through the body is the intestine, which contains earth,
swallowed partly to get it out of the burrow, and partly for the de-
eayiog planta in it.
Lesson I.

A single lobster is killed for our lesson by keeping it in warm
water for a few hours. Many pupils will hardly recognize it in its
natural dark-green coat, while others will not only know it, but
will also describe the curious lobster-pots in which it is taken on
our sea coast. Ia the interior of the country, where crayfishes
abound, the lobater is not needed, though it is an excellent plan for
the teacher to have one while the pupils have crayfishes. The
proper position for our specimen is with the back uppermost and
the head pointing away from us. As the lobster is held up in this
position before the class, some observations will be quickly made:

Its color is dark green, and reddish on the claws. Its
body is shaped like a tube. It is covered with a hard
crust. The crust is its skeleton, The body has two
parts, the head and the tail. The tail is made of rings.
The head is covered with a great shell like a saddle.

The part that has been called the lobater’s head inclades his
chest as well, and we put on the blackboard the proper names of
the parts mentioned, in this way :

The two parts of the lobster’s body are the head-thorax
(Fig. 1, cth) and the abdomen (Fig. 1, ad). The large
shield that covers the head-thorax is the carapace.

But these two parts are not the whole lobster.
What else has he ?

He has legs, claws, feelers, and eyes. He has little
flaps on the rings of the abdomen. He has a sharp nose
between his eyes.

We find that the “sharp nose” is only the pointed end
of the carapace, and is called the beak. We wonder what

61
62 Lessons in Zodlogy.

it is there for. To protect the eyes, of course. But the
legs and feelers, which are attached to the body by joints,
are all called appendages. These appendages are not all
in one piece like the bristles of the earthworm, but are
themselves jointed. For the first time we begin to study
animals with jointed appendages.

We see that the abdomen
consists of six rings and a
flattened piece at the end
called the telson (Fig. 1, ¢).

  

fig. 2.

It is not to be wondered at if the tail fin puzzles the class, with
the two broad lobes on each side of the telson, while in the cray-
fish the telson itself is jointed. But after careful observation they
will see that the telson is a part of the body, while the lobes on
either side (Fig. 1, sw®) are parts of organs that are jointed to the
body, that is, parts of appendages. If this is clearly seen, the
next question will be correctly answered.

How many appendages can we find on any ring of the
abdomen ?

There are two oneach one. There isa pair of ap-
pendages on each of the six rings, but none on the telson.

Are these appendages all alike ?
The Lobster. 68

The front pair are very smali and the hind pair very
large, but the others are nearly the same size.

These appendages are all used in swimming when the
lobster is young, so are called swimmerets or little swim-
mers. In the breeding season the female carries Ler
eggs glued to the small swimmerets.

Those who have seen a live lobster try to get away in a
hurry, know why the sixth pair of swimmerets are so large.
Their broad lobes spread out on each side of the telson
in such a way as to make a powerful tail fin with which
the lobster strikes the water, thus sending himself forcibly
backward.

We examine the third pair of swimmerets, and find that
they consist of a stem (Fig. 2, ht) bearing two flattened
lobes (Fig. 2, A? and h3).

Some of the class will doubtless observe that the second, third,
fourth, and fifth pairs of swimmerets are all made on the same plan,
but it is not wise to force any such comparison upon grammar
school pupils. When they are older it will be a part of their work
to trace one common plan in all its variations through the whole
series of appendages, but such study of homologies is for maturer
pupils than ours.

Fig. 2.—Third segment of the abdomen with its pair of ap-
pendages.

Lesson IT.

In order to give the class a correct idea of all the appendages,
we make blackboard sketches of the mouth-parts (Fig. 3), and
aleo sew the mouth-parts, the antennz, and the eyestalks to a piece
of dark-colored pasteboard.

Review of Lesson I.—The lobster is dark green, with reddish
elawa. Itis tubularin shape. Its skeleton is a hard crust. The
body is in two parts, — the head-thorax and the abdomen. The
head-thorax is covered by a great shield called the carapace. The
lobster has many pairs of jointed appendages. The abdomen has
six rings and a flat telson. There are six pairs of swimmerets on the
64 Lessons in Zodlogy.

abdomen. With the small swimmerets the lobster carries its eggs ;
with the pair of large swimmerets and the telson it takes long
jumps backward.

 

Biting Jaw, Manditle, . . . Oh
Little Jaws, or {First Mamilla, .  . en
Accessory Jaws, ;
or Maxilla, Second Mazilla, . e  aeeSS
( First Mazilliped, A te A
Foot Jaws, |

cr Maxillipeds, 4 Second Mazilliped, . . aaa

(Third Mazilliped, . Bo. ones
Fig. 3.

Outline of new work. — We will count the appen-
dages of the head-thorax. There are five pairs of legs
(Fig. 1, c'— cs), and one pair end in great claws.
There are two pairs of little legs. There are “lots of
little legs and things ” next to the big claws.

All these little legs can be seen fastened to this piece
of pasteboard How many pairs are there ?

There are two pairs of little legs. There are three
pairs that are split, and look something like swimmerets.
There are two great teeth, with a pair of tiny legs fast-
ened to them.

The three pairs next the great claws are the jaw-feet,
called also foot-jaws or maxillipeds. The next two pairs
are little jaws or maxillz, and the “two great teeth”

 
The Lobster. 64

are the pair of mandibles or chewing jaws. Let us put
our probes between the mandibles into the mouth.
These six pairs of appendages are called mouth-parts.
What other appendages has the lobster ?

He has two pairs of feelers. Those are his antenne.

What is curious about his eyes ?

They stick out from his head, and can be moved about.

The eyestalks are another pair of appendages. How
many pairs of appendages are there on the head-thorax ?

There are fourteen pairs.

How many pairs on the abdomen ?

There are six pairs.

Now we will compare the legs. How many joints
have they ?

The big legs have six joints and the others have seven.
The joints move in different ways. The first pair of legs
end in large claws, the next two pairs in small claws, and
the last two pairs in sharp points. One great claw has
broad, blunt teeth, the other has sharp teeth.

Since the lobster lives in shallow water, he uses his four
pairs of small legs in walking over the rocky bottom. The
great claws are kept for fighting and tearing his prey. If
he loses one in a duel, another soon takes its place. While
the broad teeth on one ciaw often anchor the lobster to
some large seaweed, or are used as millstones for crushing
his food, the other claw catches fish and tears them apart
with its sharp teeth.

While the great claws capture moving prey, the third pair of
jaw-feet pick up food from the bottom, and their saw-like inner
edges help to tear it in pieces. The other mouth-parts, especially
the strong mandibles, do the reat of the work of biting and ehew-
ing, though the little jaws seem too soft to be of much use.

We notice that the first pair of antennz (Fig. 1, a',)
are very short and have two parts, but the second pair
(a?) are very long and made of many little joints.
66 Lessons in Zodlogy.

The ears are in the lower joint of the small antennz, which is
flattened on the upper side and surrounded by haira. If these are
pushed apart, a small, clear, oval space is seen, which is the outer
covering of the ear.

Pupils who think a lobster needs eyes in the back of bis head,
since he takes his flying leaps backwards, see how this need is met
by the movable eyestalks, which enable him to turn his eyes in
any direction.

Lesson III.

Review of Lessons I, and II.

The following list of the lobster’s appendages is put on the
blackboard, and the children are asked to tell all that they can
about each pair :—

1 pair of eyestalks.

2 pairs of antenna.

1 pair of mandibles.

2 pairs of little jaws.

3 pairs of jaw-feet.

5 pairs of walking-legs,
Abdomen. { 6 pairs of swimmerets.

(
Head-thorax. |
|

CEPHALO-THORAK ABDOMEN

{
t
'
'
4
1
:
1
‘
1
\,

  
 
 

‘Smaue ANTeWNA.—®
LaRCEANTENNA. .__

    
  

MANDIOLE__ ~~ __
MAXILLA {b

1
MAXILLIPEDS {

3---— -~-+-

Fia. 4.

For young children these appendages may be simply classified as
eyestalks, feelers, chewing feet, walking feet, and swimming feet.
The Lobster. 67

OUTLINE OF NEW WORK.

The abdomen consists of rings, and we find but one
pair of swimmerets on a ring. Now let us see whether
the appendages of the head-thorax are borne on rings, too.

With strong scissors we cut along the groove of the
carapace, from the front half-way up the back, and bend
back the carapace, as shown in Fig. 4, thus displaying
the plumy gills, some fastened to the sides of the thorax,
others to the legs and the jaw-feet. Cutting away the
gills, we see a thin white shell, which seems to be made
of several pieces that have grown together. Now, by
lifting each leg in turv, we see that every pair of legs is
borne on one of these pieces, which are therefore the
lower portions of several rings. As we approach the
mouth and the appendages become more crowded, the
rings are completely grown together, but we conclude from
what we have seen that each pair of appendages repre-
sents a ring, and the head-thorax therefore consists of
fourteen rings soldered together.

Children must not be hurried to this conclusion, but led up to it

slowly and carefully by patient questioning. They will know only
what they discover for themselves,

We have found the gills safely hidden away under the
two sides of the carapace, in the lobster’s vest-pockets,
which are open at each end, so that the water may rush
out as well as find its way in. But as there must be
always a current of water over the gills, a spoon-shaped
organ,—the gill-scoop or. flabellum (/, Fig. 4),—attached
to each of the second mazxille, is constantly scooping it
out at the front of the pockets as fast as it rushes in at
the back. In this way a fresh supply of oxygen is con-
tinually brought to the blood in the gills.

A probe put into the mouth passes into the stomach, a
68 Lessons in Zodlogy.

wonderful machine in the top of the head. As if the
lobster had not jaws enough for tearing and chewing, he
has teeth inside his stomach, by which his food is so finely
ground that it will pass through a strainer of little hairs
into the back part of the stomach.

The heart, a six-sided, spongy organ, which sends the
purified blood from the gills over the whole body, lies
under the carapace just behind the transverse groove on
the back. We have now seen that the carapace covers
and protects the most important part of the lobster’s vody,
that containing the gills, the stomach, and the heart.

Very young lobsters are beautiful, transparent little
creatures, that swim about at the surface of the water,
and are quite different from
their parents. Fig. 5 repre-
sents one magnified, while 4
shows its natural size.

A lobster’s shell once
formed never increases in
size, and like a boy’s jacket,
must be thrown away when
he has outgrown it. This is the way the lobster pulls
himself out of it: First, the shell splits here on the back
between the head-thorax and the abdomen, or down the
middle of the head-thorax, or sometimes in both places;
then the poor fellow wriggles and twists till he gets his
head and legs out of their sheath, when with one pull he
frees the rest of his body. The new shell is formed be-
fore the old one comes off, but is very soft and loose, so
that the body can grow to fill it. Thés shell hardens and
thickens in a few days, but in this short time the lobster
has grown as much as he will until he moults again.

 
THE CRAYFISH AND THE CRAB.

Though the greater part of the lessons on the lobster applies
equally well to the crayfish (Fig. 1), still, for the sake of those who
will make use of the latter alone, a few more points may well be
brought out here.

The crab (Fig. 2) deserves our attention not only because it is so
common and easily obtained, but also because it furnishes a strik-
ing instance that children can appreciate of the changes in an an-
imal brought about by change of habit, even when the general plan
of structure remains the same. Those who can procure both the
lobster and the crayfish may devote one lesson to a comparison of
the two as a review of this important type of structure, when cbil-
dren’s quick eyes will discover many mints points of resemblance

 

Fig. 1
or difference that it is unnecessary to touch upon here. It will of
course be impossible in practice to combine the crayfish and the
crab in one lesson, as is done in this outline.

The home of the crayfish is in fresh-water streams,
where it is most active towards evening, seeking shelter
from the heat and sunshine of the day under the shade of
stones and banks. In the winter it burrows in the banks,
bot to sleep, however, for on warm days it lies at the
mouth of its burrow watching for food. Like its salt-

69
70 Lessons in Zoology.

water cousin, it is not at all fastidious, but greedily swal-
lows frogs, tadpoles, water-snails,—anything and every-
thing that comes along.

A little colony of crayfishes can be kept in a cellar or any cool,
dark place, in a tub with two or three inches of water and earth,
and stones enough for a false river-bed. They will show consider-
able ingenuity in building tiny caves, into which they beat a head-
long retreat when disturbed, and which they will rebuild as often
aswe demolish them. Unfortunately, they are cannibals, and even
if well fed with raw meat, show a wicked preference for their own
brothers and sisters, that numbers the days of our little settlement.

The dull green or brown color of the crayfish, its
smaller size than the lobster, its similarity in shape, skel-
eton, and appendages, and the equai number of append-
ages, are all noted.

 

A preparation of the mouth-parts upon pasteboard is almost
essential in the case of the crayfish, and it will be found well worth
the while to glue the carapace and the rings of the abdomen to the
center of the card, and then to arrange all the appendages in regu-
lar order on either side.

The division of the telson into two jointed pieces, the
variation in the anterior pairs of swimmerets, the differ-
ent shape of the rostrum, the lower part of the long an-
tennz, and the great claws, should then be observed.

In studying the crab, the differences between that and the lobster
at first engross our attention.
The Crayfish and the Crab. 71

It is nearly all head-thorax. The abdomen is very
small, and is tucked up under the thorax. The carapace
is broader than it is long. The eyes are nearly hidden
in two hollows under the edge of the carapace. The car-
apace has no beak, and the antenne are very small. The
great claws are bent like two arms, so that the crab can
bring them up to his mouth. All the small walking-legs
end in points. The mouth-parts are covered by two
plates.

These two plates are really the enlarged juints of the third pair
of jaw-feet.

Turning back the abdomen, we find nothing that can
be called a swimmeret, but either two or four pairs of ap-
pendages, used by the female in carrying the eggs. The
abdomen, no longer used in swimming, has become as
small as possible, and is safely kept out of the way.

But the crab is like the lobster in some respects. It
has head-thorax and abdomen. Its skeleton is a hard
shell. It has five pairs of legs, and one pair has great
claws. It has some mouth-parts. It has two pairs of
antenne. It has eyes on stalks.

By removing the under side of the carapace, which covers the
gills, and the third pair of jaw-feet, which hide the other mouth-
parts, we complete the proof that the number of appendages on the

head-thorax and the whole plan of structure are identical with
what we are so familiar with in the lobster.
THE HERMIT-CRAB.

A jar of hermit-crabs in alcohol will furnish material for a de-
lightful lesson. If but few of the children have seen them in their
homes, we begin with a short account of their habits.

Last summer I spent part of the vacation at the sea-
shore, and one day, while I was walking on the beach at low
tide, I caught sight of some snail shells moving along just
below the water’s edge. But who ever saw snails crawl
so fast? And they were on the sand instead of partly

 

Fig i

buried in it. As I stooped to pick up one, I was just in
time to catch a glimpse of a small lobster-like head and
claws disappearing inside, while one of the big claws
closed the aperture of the shell with a sharp click. I had
come upon a colony of hermit-crabs (Fig. 1). I put
some in a pail of sea-water and carried them to the house,
where I could watch them. As soon as the water in the
pail began to grow impure, the crabs left their shells
12
The Hermit - Crab. 73

entirely, and then I saw why they needed their houses.
But when I gave them a fresh supply of sea-water, how
delighted they were to crawl back to their shells, trying
first one and then another till they found one of the right
size, and then backing contentedly into it! Now let us
examine our specimens.

 

The body is nearly all soft. It has a shell on the head
and claws and a little shield over the heart, but the abdo-
men is so soft that it almost breaks in two.

Why does the hermit-crab carry a snail-shell on his
back ?

To protect his soft body.

Has he the same appendages as the lobster ?
74 Lessons in Zodlogy.

He has two eyestalks, longer than the lobster’s. He
has two pairs of antenne. (Fig. 2, a, the long antennz.)
He has one pair of hard mandibles. I think he has just
as many mouth-parts as the lobster.

You are right. He has two pairs of little jaws and
three pairs of jaw-feet.

He has one pair of great claws (Fig. 2, ct) and four
other pairs of walking-legs (Fig. 2,c?-c5). One big claw
is larger than the other.

Moat of the class will find that the right claw is larger than the
left, because the aperture of most snail-shella is on the right side,
and this claw is used to close it up when the crab is inside.

The walking-legs are different from the lobster’s. The
second and third pairs are long and pointed at the end,
and the fourth and fifth pairs are short and end in little
claws.

The last two pairs are probably used only for holding
the creature in the shell.

Are there any swimmerets ?

There are three or four on the left side (Fig. 2, s?-s5),
and one pair at the end of the abdomen (s‘).

The male has but three appendages on the left side of the abdo-
men, but the female has four, which are longer than those of the
male because used in carrying the eggs. Both have the pair at the
end, used ag claspers. The hard crust on this pair and on the last
two segments of the abdomen, a hard ridge (Fig. 2, r) on the under
side of the abdomen, and a projection (p) close to it on the left
side, all help to hold the crab in his shell.

In looking for the gills, we trace the flap that covers them up to
the side of the body, where it shows beautifully that it is nothing
but a double fold of skin, thus making clear to teacher, if not to
pupils, its real structure in the lobster.

One can hardly find stronger proof than in the hermit-crab that
an animal becomes adapted to its surroundings, and also that parts

uoused will either disappear or so far degenerate as to be incapable
of use.
THE BEACH - FLEA.

We may choose either the Gammarus (Fig. 1), colored like the
heavy masses of dark green seaweed under which it hides, or the
equally nimble Orchestia, so precisely like the sea-sand in its color
that many a one escapes from us as we dig into their holes on the
beach. The Gammarus is the one firat described in this lesaon.

Observations to be made: The beach-flea has a very
narrow body, strougly curved for jumping. The rings
can be seen on the whole of its body except the head.

 

FIia.1.

The last four rings of the abdomen are narrower and
harder than the others. There are seven pairs of legs in
all. Two pairs of these have great claws. There are
six pairs of swimmerets. The first three pairs of swim-
merets are soft, the others are hard because used ia
jumping. There are two pairs of antennz. The eyes
are like two curved black lines, and are not on stalks.

An interesting comparison may be made between the
shape of the body of Gammarus and that of Orchestia.

The former has so narrow a body that it cannot stand
75
VC Lessons in Zoology.

upright, euited to the crevices through which it must
often make its way; while the latter, which burrows in
the yielding sand, has a much broader thorax, and can
keep its balance in an upright position. Ganmarus, how-
ever, must always swim on its side or back.

The beach-flea has no carapace covering both head and
thorax. Remembering that the thorax is that part of the
body which bears the legs, we count seven rings of the
thorax, each bearing a pair of legs. The first ring of the
thorax, that nearest the head, is so small that we must
take it on trust, but bears a pair of jaw-feet, nevertheless.
The first pair of legs end in rude pincers formed by bend-
ing the little hooked claw backward toward the next joint
above, which is somewhat broadened. The second pair
have larger pincers of the same sort, with the joint above
the last much more broadened. The remaining five pairs
all end in single claws. The pear-shaped bags at the
base of the legs are the gills.

We are careful to aay only that we count seven rings of the thorax,
for we know it really consists of eight, even if we can see but seven.

The mouth-parts are so tiny that they can scarcely be
seen without a magnifying glass. They consist of the
pair of jaw-feet already mentioned, two pairs of maxille,
and one pair of mandibles. The head also bears two
pairs of anteunz nearly equal in length.

By placing the head under a magnifier and pressing back the
jaw-feet with « pin or a dissecting needle, a careful worker may
satisfy herself that the hard mandibles and the maxillx, soft and
leaf-like, are really present.

Now taking Orchestia and comparing it with Gammarus, we
make the following discoveries :

The eyes are not on stalks, and are nearly round.
The first pair of antennz are very short, indeed. Plates
The Beach- Flea. 77

of shell cover the legs just as in Gammarus. The Jast
four rings of the abdomen are very small, and the last
three pairs of swimmerets are hardened and much
crowded. There is but one pair of pincers, and these are
on the second pair of legs. The mouth-parts are the
same as in Gammarus, but are more plainly seen.

There are no pincers on the first pair of lega, but the section
above the last is turned downward and the terminal claw bent
toward ic, as if in the attempt to form pincers. An interesting
series may be made, beginning with this rude suggestion of a grasp-
ing organ, placing next the first pair of pincers in Gammarus,

then the second pair in Gammarus, and finally the second pair in
Orchestia, in which the pincers have attained their greatest size.
THE SPIDER.

Lesson I.

The common large, brown, long-legged spider (Fig. 1), which
spreads its web on plants and rests securely in the tube leading
downward from it, is the one described in these lessons. We use
alcoholic specimens. The large black and yellow field and garden
spider is another excellent one for class use, and is so common that
it is easy to collect a sufficient number. Still another good one is
the great round-web spider, often found
in barns, but its body is softer and more
easily injured.

A small round-web spider has also
been imprisoned in a box with a glass
cover, where its movements could be
watched. We have seen that it did not
rest until it had spun in every direction
through the box, so that it could go
anywhere in its new home without step-
ping off the threads. When this was
finished, it was fed with flies, and the
process of killing them carefully ob-
served, from the time when they were
first bound with tiny ropes till they were
let fall, dry and juiceless, to the bottom
of the box.

The bodies of spiders are so soft and
so easily broken that it is absolutely
necessary to fasten them to bits of
cork by a pin through the thorax if they are not to be ruined in
the handling. A large pin and a bristle are also given to each
child, since the probes are too clumsy for use upon such little
creatures,

 

Facts Already Learned by Observation:

The spider in the box has spun threads across it in’
78
The Spider. 79

every direction. It hangs upside down in its web. The
spider tied up a fly in the web and held it there a long
time, then it took off the threads and let the fly fall on
the bottom of the box. The spider has four pairs of
long legs. It hasa big head and a round body with
spots on it.

This last observation will soon be corrected from the alcoholic

specimens. These must now be held with the back uppermost
and the head pointing away from the pupil.

Outline of new discoveries :

The spider could be cut in halves by cutting length-
wise from front to back. The spider’s body has two
parts. Since the front part bears the legs, it must be the

 

Fie 2

head-thorax, and the other part is the abdomen. The
abdomen is very soft and looks as if it might break off
from the head-thorax. The skeleton is a horny crust
covering the outside of the body. There is a dark band
down each side of the head-thorax, and some dark stripes
and spots on the abdomen. There is a little hollow near
the hind part of the head-thorax.
80 Lessons wn Zoology.

This hollow shows where the large muscle that moves the suck-
ivg-stomach is attached. By the contraction of this and opposing
muscles below, the top and bottom of the stomach are urawn
apart, and the spider’s liquid food is pumped backward from the
mouth to the intestine.

The spider has one pair of short legs besides the four
pairs of long ones. It uses the long legs for walking,
and holds the others out in front like feelers. The first

pair are not legs, but jointed feelers, called palpi.

In the young epider (Fig. 2) the young legs are shorter in pro-
portion to the size of the body, and the palpi are evidently |: ga
and are so used. Afterwards they do not lengthen as much
as the others, gradually take w different position, and being
used aa feelers, are called palpi. The distinction between these
and the legs needs to be clearly brought out, beeause we must
think of spiders as having only four pairs of legs. Short palpi with
broad and apparently distorted tips show that the specimen is
a male.

Lesson IT.

Review of Lesson I.—Spiders can spin webs. They catch insects
in the webs for food. The body is in two parts, head-thorax and
abdomen. The abdomen is large and connected with the head-
thoraz by a small joint. The spider has four pairs of long legs
and one pair of palpi. The palpi are used as feelers.

The spider must now be held with its head toward the pupil.

There are eight eyes (see Fig. 1), Under the magni-
fier they look like tiny black beads. In front of the head
are two clumsy
things with little
hooks on the end
of them (Fig. 1).
They look like
short legs, and |
can push them
from side to side
by pressing my

 
The Spider. 81

pinin between them. I think the spider bites with them.
They are its mandibles or biting-jaws. I can put the
bristle into the mouth just between the mandibles. The
spider does not need a large mouth because it only sucks
the blood of the insects that it catches. On the under
side of the thorax, close behind the mandibles, are the
maxiliz or little jaws (Fig. 4, a). They are not separate
appendages, but the flattened first joints of the palpi,
which are used in chewing.

Figs. 3 and 4 represent the greatly magnified mandibles and
maxille of a common garden spider, but not the one we are studying.

The appendages of the head-thorax are four pairs of
legs, one pair of palpi, and one pair of mandibles.

When a spider bites, the poison is poured out through a tiny
hole at the tip of each mandible. The poison sacs are partly in
the head and partly in the
upper joints of the man-
dibles.

The abdowen has no
appendages but the spin-
nerets. In our spiders
two of these are long and Fic. 4
stand out behind the »bdomen like two tails (Fig. 1).
Most spiders have three pairs of spinnerets shaped like
so many knobs. By rubbing one of the hind feet over a
spinneret a sticky fluid like white of egg is drawn out
of all the little tubes in filaments, which instantly harden
in the air. Hundreds ot these strands unite to make

the spider’s thread, so delicate and yet so wonderfully
strong.

 

Fig. 5 ig one of the long spinnerets of our spider with the tinv
spinning-tubes, sp, on the under side of the last joint. Fig. 6
thows the end of «spider’s leg with the two-toothed claws, 0, and
the middle claw, m, without teeth, which is used as a thumb in
holding ard guiding the thread. These claws, as well as the
toothed hairs, ¢, and all the other hairs on the Jeg, are so highly:
82 Lessons in Zodlogy.

polished that it is impossible for a spider to be caught in her
own web.

Just in front of the epinnerets is the small opening of the air-
tubes, and farther forward are two openings leading to the pair of
sir-sacs, in which the blood is purified aa it passes through delicate
membranous leaves.

 

The eggs of spiders are Jaid in dainty cobweb cases
often found under sticks and stones, or hung up in barns.
Some spiders carry their young about on their backs
until the little ones can look out for themselves.

Fig. 2 is a magnified view of a young spider just from the egg,
with the first moult, m, still adhering to the end of the abdomen ;

y is the eame spider, natnrsl size; and /, the end of a leg greatly
magnified to show an outer skin not yet shed.

 

Fic, 6.

Many spiders live through the winter, hiding under
fallen leaves and coming out the first warm day of spring.

Suggestions for Further Ohservation.—How does the
round-web spider hegin the wep? Inspinning the spiral,
does she go from the center to the outside or from
the outside to the center? Does the garden spider gen-
erally stay on her web? Why does the little gray jump-
ing spider look so much more wide awake than others of
the same size? Are there any epiders that are protected
by their color ?
THE GRASSHOPPER.

Lesson I.

The very largest grasshoppers we could find have been preserved
iv alcohol, and from a friend in Florida we have a small jar of the
great ‘‘lubber grasshoppers,’’ three or four inches long. Of our
common ones, the flying grasshoppers make the best specimens,
because they show so plainly the structure of the hind wings. We
pin them to bits of cork, and also distribute pins before beginning
the lesson. This insect is so familiar that the children are first
allowed to tell what they know of its habits, and as many points
of structure as they can discover for themselves, without much
questioning. Some of the following observations are made:

 

The grasshopper has one pair of long legs and two
pairs of short legs. It lives in the grass, and jumps
with its long legs. It has two pairs of wings. It has a

&3
84 Lessons in Zodlogy.

saddle on its back like the lobster. It has one pair of
antenne. It has two large eyes. It has a head-thorax
and an abdomen.

Is there any movable joint between the lobster’s head
and its thorax?

No; the head-thorax is all in one piece.

If there is a joint between the grasshopper’s head and
its thorax, which bears the legs, then we will say it has a
head and a thorax. Has the grasshopper a head-thorax
or a head and a thorax?

It has a head and a thorax.

What are the three parts of the grasshopper’s body ?

The head, the thorax, and the abdomen (Fig. 1,
A, B, C).

We observe next that the grasshopper has jointed ap-
pendages, that its skeleton is a horny crust on the outside
of the body, and that it can be divided into two equal
parts by a cut lengthwise from the head to the end of the
abdomen. We stop a moment to recall other animals
that we have studied whose bodies can be divided in
halves in the same way.

An extremely careful coust shows us that the abdo-
men consists of ten rings. The only appendages of the
abdomen are three pairs of hooks, or “ egg-points,” at
the end, forming the egg-layer. A large oval spot on the
first ring (Fig. 1, ea.) is the ear, one on each side. We
think this a curious place for the ears, but remember
that the lobster carries its ears in its small antenne.

The first ring of the abdomen (Fig. 1, c!,) can be seen only on
the back, as it does not reach wholly around the body, while in the
male the ninth and tenth (Fig. 1, &°, &7,) are much larger on the
under side. It is often said that the ovipositor consists of but twu
pairs of organs (Fig. 2, os! and 0s*,), probably because the third
pair (Fig. 2, 0s®,) are very small and not readily seen unless
the parts are distended. Neither are nataralists agreed as to the
The Grasshopper. 85

eara, They are certainly sense-organs, but may not be organs of
hearing.

The collar behind the head at first almost deceives us
into thinking it the whole of the thorax, but we remem-
ber just in time that the thorax bears all the legs, so this
ean be only the back of the first ring. On good speci-

 

Big -

mens, children can see that there are two rings behind
this, both bearing legs. The thorax, then, has in all
three rings, and bears three pairs of legs.

On the side, the second and third rings of the thorax, appear to
be four rings instead of two. This is because the side of each ring
consists of two plates (Fig. 1, B, h? and hs?, A8 and hs®), which, in
the typical ring, lie one above the other. the upper one of which
has here been forced out of its proper place until it lies behind
the other.

The number of joints in the legs, the sharp spines with which
they are armed, and the soft cushions padding the feet, will all
interest the children, who will like to spend as much time on these
points as can be well spared for them.

The second and third rings of the thorax bear the
wings. The first pair of wings are straight and long.
They meet on the back and cover the hind wiogs. The
hind wings are broad and thin, and folded like a fan.
In the flying grasshopper they are often beautifully
colored. The hind wings are the ones chiefly used in
flying, and the fore wings are made hard to protect them.
86 Lessons in Zodlogy.

Lesson II.

The best way to learn the external anatomy of this or any other
insect is to separate the body into its various parts, and arrange
them on a card with the appendages in their proper places beside
them, as shown in Fig. 1. Even if children cannot do this with
perfect succers, they will learn much in the attempt.

an md
ee

 

 

 

 

 

   

ow
08

Fig. 3.

Review of Lesson I, — The grasshopper has head, thorax, and
abdomen. Ita skeleton is a horny crust that covers its body. It
baa jointed appendages. The thorax has three rings. On the
thorax are three pairs of legs and two pairs of wings. The hind
wings are folded like a fan, and the others are long and straight.
The hind legs are long for jamping. The abdomen has ten rings
aud bears the egg-points. The ears are on the first ring of the
abdomen.
The Grasshopper. 87

Outline of New Work. — The head is long and moves
freely on the neck. There are two large eyes, one on
each side of the head. The grasshopper has one pair of
antennz. In the center of the forehead is a simple eye
(Fig. 2, oc,) that is easily seen, while two more simple
eyes (Fig. 2, oc',) are placed, one on each side, in front
of the compound eyes.

Holding the head of the grasshopper firmly between
the fingers, and raising the loose flap that covers the
mouth-parts, called the labrum, or upper lip, (Figs. 1
and 2, la,) we see the hard, dark
brown mandibles (Fig. 1, md,) having
strong, toothed edges with which the
grasshopper cuts off Jeaves of plants.
Between these is the mouth. Below the
mouth lies what is often called the under
lip, but is really a pair of united ap-
pendages, the second pair of maxille
(Fig. 1, max?). Above these and nearly

Fig. 4. hidden between them and the mandi-
bles are the first pair of maxille (Fig. 1, mx'). In
Fig. 2 only the palpi or jointed feelers of the maxille
are seen.

Fig. 3, tn, ig the tongue, which is between the first pair of
maxille.

Some of us have watched the grasshopper breathe, and
know how he seems to pant as his body contracts and
expands. We look on the sides of the abdomen for the
breathing holes. Here they are, seven of them in plain
sight, and another high up on the first ring in front of
the ear (Fig. 1, C, s3-s%). They look like tiny pin-
holes, just above the fold on each side of the abdomen
and close to the forward margin of each ring. If these
do not show plainly, a larger pair on the thorax (Fig. 1,

 
88 Lessons in Zodlogy.

B, s?,) can often be seen a little above the second pair of
legs. There is also one more pair on the first ring of the
thorax.

Through the breathing holes air passes to the wonder-
ful sets of air tubes and air sacs found in every part of
the grasshopper’s body. Fifty-three of these tiny bal-
loons have been counted in the head alone. A body
made so light and buoyant is easily carried through the
air by the strong wings.

The baby grasshopper, called the larva, is like its
mother, but has no wings. In order to grow it must
throw off its outer coat, just as the young lobster does.
After it has done this three times little wing-pads appear
on its back, and it is now called a pupa. Twice more it
casts off its coat, and now it is the full grown imago,
ready for flying or jumping.

The note of the grasshopper is produced by rubbing
the small teeth on the inner side of the thigh of the hiad
leg against the veins on the outer side of the fore wing,
or wing-cover as it is often called. It is easy to show
how this is done by drawing a comb over the edge of a
piece of stiff paper.
THE CRICKET.

Most of our cricketa are females (Fig. 1) collected by the chil-
dren in October as they were laying their eggs by the roadsides or

in gravelly walks. After studying the
grasshopper, it is easy to begin work
upon this insect, and natural to compare
the two at every step.

The cricket has a shorter and
broader body than the grasshop-
per. The two sides of its body
are alike. The body is in three
parts,—head, thorax, and abdo-
men. It has one pair of very long
antenne. It has a pair of com-
pound eyes, not so large as the
grasshopper’s. It has three pairs
of legs on the thorax, the hiad pair
very long because it isa jumper.
The forward wings, or wing covers,
are short, covering only part of the
abdomen. The hind wings are

 

 

FIG. 1.

very small and of no use in flying. At the end of the
abdomen there is a long bristle (Fig. 1, se) on each side.

The egg-layer looks like a long sting (0s).

Nine rings ean be plainly counted on the back of the abdomen of
the female. On each side of the abdomen is a soft space where
the breathing-holes are seen. The ovipositor separates into two
parts and each of these into two more, making four long, sharp

89
90 Lessons in Zodlogy.

piercers, which bore a hole ia the ground and then unite to form a
canal through which the eggs pass down into the earth.

The first ring of the thorax has a cape like the grass-
hopper’s, but a straight, broad one, much more like a wide
collar. The three rings are plainly seen on the under
side. The hind legs are long but not so strong as the
grasshopper’s. The wing-covers are bent to fit the sides
of the body. The wing-covers of the male are larger
than those of the female, and have a different arrange-
ment of the veins.

It is by rubbing these strong veins of the wing-covers together
that the male cricket makes the lively chirp we know go well.

The head of the cricket is shorter and broader than
that of the grasshopper, but like that is placed at right
angles to the body. The eyes are not so large as the
grasshopper’s. The palpi are longer than the grasshop-
per’s. Just below the upper lip the hard mandibles can
be felt. With a pin the first pair of maxillze with the
long palpi can be pushed outward, and the united second
pair of maxillz with a shorter pair of palpi can be bent
downward.

The strong mandibles are evidently fitted for biting, and we
know that crickets do eat the tender parts of plants, even attack-
ing roots and fruits. When abundant, they do great damage.

The eggs laid in the autumn are hatched the next sum-
mer. Most of theold insects die before cold weather
comes, but a few live through the winter under stones or
in dry holes.

The children must not fail to see and admire the white climb-
ing cricket, daintiest and most delicately fashioned of all oar New
The Cricket. 91

England crickets, which lives on trees and shrubs, but often seeks
the shelter of our houses when the cooler
nights come in early autumn. The male
(Fig. 2) is white with a few yellow mark-
ings, with antenpz and lega so fragile and
slender that a single careless touch will
ruin a specimen. But let one perch on the
window-sill for one night, and we see how
effectually this delicate little creature can
banish sleep. By rubbing together the
three large oblique veins on the flat surface
of the wing-covers he produces the loudest
and shrillest of all cricket notes, and keeps
up his serenade with unfailing energy and
patience till daylight. The female, which Fig 2

has no note, is somewhat larger than the male, with narrower wing:
covers and of a pale greenish or yellowish color.

 
THE BEETLE.

Specimens for this lesson are obtained on warm May or June
evenings, when the blundering brown May-bug, June-bug, or dor-
bug (Fige. 1 and 2), as it is variously called, enters at every win-
dow left open after the evening lamps are lighted, and in its head-
long fashion goes bumping into anything and everything that stands
in its way. It is said that they may also be collected by shaking
the fruit trees, where they hide, at an early hour in the morning,
when they do not attempt to fly, but fall to the ground. These
beetles do so much harm in our gardens that we do not hesitate
to put as many as we need into our bottle of alcohol. For our in-
sect-boxes we pin beetles through the right wing-cover.

 

FIG, 1. Fie, 2.

The children are all sure this is a bug; they have
always heard it called so, and the word beetle is not
found in their vocabulary. But Figs. 3 and 4 show that
the bug has a long sucking-tube, which the beetle has not.
This will be a sufficient distinction for the present, until
true bugs are studied. Now we call our specimen the
June-beetle.

What has the beetle that the grasshopper and the
cricket have also?

It has the three parts of the body,—head, thorax, and
abdomen. It has three pairs of legs. It has two pairs

of wings. It has one pair of compound eyes.
92
The Beetle. 93

Later we shall add that it has one pair of antennz, but the chil-
dren may not see them on this beetle till the head is carefully ex-
amined by itself.

The grasshopper, the cricket, and the beetle, are all
called insects. In studying our new insect we will com-
pare it with the grasshopper.

The body is shorter and broader than the grasshopper’s.
It is covered with a horny crust, much harder than the
grasshopper’s. This crust is its skeleton.

The fore wings are like two hard shells covering the
back. They protectthe other wings, and are called wing-
covers. They meet in a straight line down the back,
and cover the hind wings completely. If we should cut
the beetle in two between the wing-covers, the two halves
wouid be just the same size.

   
  

: ‘ 5 SS
There is a little shield be- ANTEN#4--\ 3
tween the wing-covers. (ee
\ Fig. 3.
The firat ring of the thorax Mouth-Parts
is very large, the second and
f Bug.
third, though large, are not pe
seen on the back, with the ex-
ception of the little shield that Fig. 4.
belongs to the second ring. Mouth-Parts-
The hind wings are of Beetle

thin with very strong
veins and a joint near the
middle so that they can be doubled up under the wing-
covers.

The female uses the strong spines on the legs in digging her way
into the earth, where she lays her eggs.

The broad and short abdomen is soft on the back be-
cause protected by the wing-covers. There is no egg-
layer. The breathing-holes are plainly seen on the sides
of the rings.
94 Lessons in Zoology.

The beetle has a pair of compound eyes. It has a
little flat piece that comes out over the mouth. There is

tapium____---. +4 ae

a

MAKXILLA__ ~~~ -- & _ _ MouTH PARTS g

MANDIBLE___ COAX =
Anfewnan 222% a

ETI en iss sesso
ComPounb Eye — 2 QsS-s5--="' HEAD
First Leg__.. >

PROTHORAX :

=

ELYTAON,on RST S

wi RS

 

Fie. 5.

a pair of queer little things that have an elbow near the
middle and a little club at the end. These must be the
antennz, and the little club is made of three leaves.

With magnifying glasses we also see at least one pair
of palpi, and with a pin we assure ourselves that the
beetle has hard mandibles.

From the card on which the mouth-parts are glued, and from
the blackboard drawing of Fig. 4, he
class observe that the beetle has tbe
same mouth-parts as the grasshopper.
In Fig. 5 the united second maxillae
are indicated by their other name of
labiam or lower lip.

On a male stag beetle (Fig. 6)
we now find the enormous
hooked mandibles, the long first
pair and short second pair of
palpi, the sort of tongue formed
of brushes of hairs attached to

 
The Beetle. 95

d

both pairs of maxille and the antenne ending in four sepa-
rated leaves.

The grub of the June beetle (Fig. 7) is a large
white worm with a brownish head and strong jaws, which

  

Fic. 8.

lives in the earth and devours the roots of grass and
other plants. The pupa (Fig. 8) lies quietly in its
cocoon in the earth until it comes out as the perfect insect.
THE DRAGON- FLY.

Dragon-flies may be caught with a net near ponds and streams,
where the larve are found in the water duriog July and August,
and the pup in spring and autumn. The larve and pup can be
kept in the schoolroom in a jar of water, with sand at the bottom.
The latter will need a water-plant, or some leaves and twigs, to
which they can cling. The contrast between the sluggish young
and the swift-flying adult insect will seem to children so marvelous
that it will awaken a new interest in insect study. It gives them
a glimpse of the possibilities the insect world offers of new
discoveries, and makes them eager to observe living forms, the very
thing we most want them to do.

 

Fig. 1.

The dragon-fly has the three parts of the body, but the
abdomen is very long. His head is so loose it louks as
if it might drop off. He has a hump on his back because
his thorax is so high. He has three pairs of legs and two
pairs of wings. The legs are all crowded together. The
wings are very large, and the two pairs are nearly the

same size. He uses both pairs in flying. The dragon-fly
96
The Dragon-fly. 97

has enormous compound eyes, that meet on the top of his
head. His antennz are only two little bristles.

The abdomen has ten rings. It has a very small
egg-layer.

The horny ridges on the second and third rings, one of which is
seen in Fig. 1, may lead pupils to count twelve rings instead of ten,
but by comparison with the sutares between the rings, the ridges
are seen not to be true sutures.

All the rings of the thorax can be seen on the back of
the dragon-fly. The first ring is very small, but the
second and third rings are large because they carry those
great wings. The wings are beautifully veined. There
are long, straight veins on the
front margin, and the rest of
the wing is net-veined.

  

Fig. 3.

As the dragon-fly never alights, but always hangs by the second
and third pairs of feet, the lega are drawn forward and the rings of
the thorax inclined in the same direction. A voracious eater, the
deadly enemy of gnats and mosquitoes, the dragon-fly must catch
its food ‘on the fly.’’? For this purpose, see ita immense compound
eyes, literally ‘‘on all sides of its head’’; the head itself so loosely
hung that it can be turned in any direction, or thrown backward
till it touches the second ring of the thorax, while the first ring of
the thorax moves so freely that the first pair of lega, used only for
seizing prey, can readily follow the rapid motions of the head.

Grasping the head and thorax of the dragon-fly firmly,
and looking at the head from in front, as shown in Fig. 2,
we see a little horny projection in front of the compound
98 Lessons in Zodlogy.

eyes and between the antennz. The largest of the simple
eyes (Fig. 2, oc) is in front of this projection, the two
smaller (0c’) at either side of it. The upper lip (/a) is
easily lifted with a pin, and just below it are the dark
brown, horny mandibles (md) and the second maxillz
(mz’’), which hide away in their broad cavity the small
first maxilla and the thick tongue.

Fig. 3 representa a larva collected in August, three times life
size, mz’’ being the mask; w’ and w”, wing-pade just appearing.

 

dig 4:

In Fig. 4, the pupa is shown with the spoon-shaped
mask (mx’’) extended to seize food. This mask is the
greatly enlarged second pair of maxilla, and when not in
use, is folded back over the mouth so as to hide the
strong mandibles.

The dragon-fly lays its eggs on water-plants. When
the pupa is ready for the last change, it climbs up on
some plant, the skin of its back splits open, and the
dragon-fly pulls itself out. This insect does not deserve
the name “ darning-needle,” since it has neither sting nor
powerful jaws, but its threatening appearance may well
gain for it the name dragon-fly.
THE BUG.

Most of us have a prejudice against bugs, which has some reason
for its existence in the disagreeable character of many that bear
this name, but the remarkable adaptations to their mode of life
shown by some of these in-
sects will awaken our inter-
est in spite of ourselves.

The equash-bug, shown
enlarged in Fig. 1, gives a
good idea of the character-
istic form of the body, and
also of the peculiar wings,
and igeasily found on squash-
vines. It is too small for
the mouth-parts, but these
are well shown by the com-
mon Cicada, or harvest fly
(Fig. 2), while if the teacher
can have one of the ‘‘ giant
water-bugs’’ (Fig. 3), she
will find it invaluable. One of the most interesting species, and
therefore one that we cannot afford to do without, is the lively
water-boatman (Fig. 4), which children can collect from the ponds.

 

Fira. 1.

The squash-bug has a small, pointed head. It has
head, thorax, and abdomen. The abdomen is flat on the
back and rounded below. The head is much lower than
the back of the thorax and the abdomen. There are
three pairs of legs, used for walking, not for jumping.
There are two pairs of wings. The forward pair are
thickened in front and thin behind, and they overlap.
They are called wing-covers. The hind wings are thin.

Some will undoubtedly fail to see from their specimens that the
wing-covers are half membranous, but the ‘‘ giant” will make this

very clear.
a 99
100 Lessons in Zoology.

The abdomen has no appendages. It has a little rim
spotted with yellow, that comes out beyond the wing-
covers. The breathing-holes are on the sides.

 

Fie, 2.

On the under side of the body the three rings of the thorax are
seen, but only the firat ring (Fig. 1, 0’) and the shield (b’’) of the
second on the upper side.

Besides the two rather small compound eyes, there are
two simple eyes. The antennz
are long and rather large. The
mouth parts look like a long sting.

The mouth-parts of the Cicada are
like those of the squash-bug magnified,
and are large enough for children to

separate and describe, so
we turn to the Cicada now.

Fig. 5 is a magnified
view of the head of the
aquash- bug with the mouth-
parts separated.

There are two pairs
of long, sharp needles
for piercing (Fig. 5, Fie 4.
ma’, md). There is a short, horny upper lip (ia).
There is a long, jointed tube (ma’’), in which the two
pairs of needles lie.

  
The Bug. 101

Since we have always found three pairs of mouth- parts on insects,
and have already seen that the second maxilla may be so changed
as to form the mask of the young dragon-fly, children will see after
a little questioning, if not before, that the long tube ia the second
pair of maxillse, and the needles are modified mandibles and first
maxille. The tissues of plants are pierced with the sharp needles,

 

Fic. 5.

and their juices are drawn in through the sucking-tube. The tri-
angular head, with its broad base, is firmly braced against the
broad thorax to furnish a strong support for the thrust with the
needles,

In August the light brown larva (Fig. 6, three times
life-size) and the pupa of the squash-bug can be collected
on the leaves of squash-vines. The puparesembles the full-
grown insect, but is lighter :
in color and has only wing-
pads in place of wings.

Comparison of the beetle
and the bug.— The beetle
has a hard crust. Its wing-
covers are hard and horny,
and meet in a straight line
down the back. The hind
wings are doubled up under
the wing-covers. The beetle
has hard mandibles for bit- Fig. 6.
ing, and twopairs of maxille with palpi.

 
102 Lessons in Zotlogy.

The bug has wing-covers half horny and crossing on
the back. It has a small, pointed head. Its mouth-
parts are a sucking-tube and two pairs of needles.

This comparison is svfficient to enable one always to distinguish
these two orders of insecta. If, however, we have observed them
in all stages of growth, we can add the very important difference
that while the young bug resembles its parent in a general way and
the active pupa ia still more like it, both living on squash-vines,
the larva of the June beetle is worm-like and lives in the ground,
and the pupa is quiet in a cocoon.
THE CICADA.

The Cicada, or harvest-fly, will furnish material for an interest-
ing leszon. An abundance of the cast-off pupa skins can be col-
lected by the children, and will not only show perfectly the ap-
pearance of the pupa, but will give an excellent idea of the horny
external skeleton of an insect and the complete manner in which it
is stripped off to allow for growth.

The body is broad and short. The eyes (Fig. 1, ey)
stand out on the sides of the head, and there are three
simple eyes between them. The antennz (at) are like
bristles. The first and second rings of the thorax (4’ and
6”) are very broad ; the third is very narrow, because it
carries only the small hind wings.

 

Fig. 1.

There are light spots on the head and thorax, and on the second
ring of the thorax a marking that looks like the letter W. This
mark was long supposed to stand for the word War, and made the
superstitious believe the harvest-fly an insect of ill omen.

The wings slope like a roof over the sides of the body,
and both pairs are thin. The veins of the fore wings
are very large and strong. The abdomen ends in an egg-

103
104 Lessons in Zoology.

layer. Some of the harvest-flies have two broad plates
on the under side of the abdomen.

These plates are found on the male, and cover the kettledrnme,
by which he makes the shrill sound we know a0 well in dog-days.

The mouth-parta having been described in the last lesson, are
omitted here, but would of course be reviewed in the schoolroom.

The pupa has very large fore legs, like great claws.
It has a sucking-tube like its parent. All the rings of
the thorax show plainly. The first and second rings are
very large; the third ring is small. The horny outer
layer of the antennz and the eyes is cast off with the rest
of the skeleton.

 

Fig. 3.

 

With the strong, horny piercer at the end of the abdomen the
female makes hollows in twigs in which to lay her eggs. The
larva (Fig. 2) is hatched on the tree, but lets itself fall to the
ground, being so light that it descends very slowly and is not injured
by the fall. It then burrows in the earth, where it sucks the sap
from roots. One species of harvest-fly passes seventeen years in
the earth as larva and pupa; others common in New England re-
quire only one or two years for their transformations. The pupa
at last digs its way out of the earth with its big fore claws, climbs
some tree, its skin splits on the back, and the barvest-fly comes out.

Fig. 3 shows the insect making its way out of the pupa skin.

The water-boatman, mentioned in the last lesson, is a different
type, and should be studied from living insects kept in jars in the
The Cicada. 105

achoolroom, The jara must be covered with netting to prevent
these active little bugs from flying away.

We discover that the water-boatman is a true bug by
feeding it with meat and watching tbe sucking-tube, or
by handling it carelessly and letting it use its sharp
needles on our fingers.

Its body is boat-shaped, its back being the keel, hence
it swims back downward. The under side, which is flat,
forms the deck, with an upper deck of hairs above it.
Under the wings it keeps the supply of air for which it
often comes to the surface. The fringed hind legs are
the principal pair of oars, working smoothly in their row-
locks. The other two pairs are held out in front for
seizing prey. It feathers its oars by pressing the hairs
to the hind leg when drawing it forward, and spreading
them in drawing it back.
THE FLY.

The big buzzing ‘‘ blne-bottle,”’ or any of the common flies found
about houses, can be used for this lesson, though the green-headed
horse-fly (Fig. 1) is better, if it can be obtained. Most of the de-
scriptions here given will apply to either of these. The crane-flies
with their delicate wings and long, slender bodies, are also invala-
able as specimens.

The fly is an insect. It has a short, broad body. It
has head, thorax, and abdomen. It has three pairs of
legs. It has one pair of wings and one pair of balancers

 

Fig. 1.

The last statement can be made only after careful observation.
The little scale or winglet on each side (Fig. 2, sc) will at first be
taken for another wing, but after drawing the wing forward several
times we discover that the winglet moves with it and must be »
part of it. Hence there can be but one pair of wings. Just under
the winglets is a pair of tiny whitish knobs on slender stema (Fig.
3, w”) known as the balancers.

Fig. 2 represents the second ring of the thorax of the horse-fly,
and Fig. 3 the third ring, with the appendages of one side. The
balancers, being the greatly reduced second pair of wings, are borne
on the third thoracic ring.

106
The ly. 107

The fly has very large compound eyes that make its
head look very broad. The house-fly has short, feathery
antennz. Its tongue is large and broad at the end.

The abdomen is very short and broad in front. It is
covered with hairs. We can see only four or five rings.

 

Fig. 2.

The thorax is nearly as large as the abdomen. It is
covered with hair. It is joined to the head by a small
neck. The legs are all nearly the same size. The feet
have two claws and two little light-colored cushions.

 

Fig. 3.

The little cushion, so deeply cleft that it looks like two. has on
ita surface haira that pour out a sticky liquid by which the fly clings
when walking upside down.

The antenoz of the house fly are usually in alcoholic specimens
bent down closely against the face, but with the feathery bristles
projecting more or leas, so that one is apt to mistake them for the
108 Lessons in Zovlogy.

whole of the antennz. They are really, however, attached to one
side of the true feelers. The tongne, consisting of the modified
second maxillx, is the only conspicuous mouth-part. There are
neither mandibles nor first maxille in this form, but with a good
magnifying glass one can see the large palpi of the first maxilla
and the long, horny upper lip closely pressed over the upper side
of the tongue. The two broad lobes that form the end of the
tongue are roughened by cross-bars (Fig. 4).

 

Fig. 4.

The house-fly simply laps his food, and has no need of
pincers, but the horse-fly has sharp, lance-like mandibles
(Fig 4, md) and first maxille (mz’), adapted for piercing
the skin of horses and caitle, in addition to the long la-
brum, or upper lip (Ja), the broad tongue (mzx’), and the
palpi of the first maxilla (#). The antennx (at) are
also shown. In the curious large robber-flies, or insect-
hawks (Fig. 5), which attack bees, beetles, and other in-
sects, the mouth-parts form a powerful black sting.

The eggs of the house-fly are laid in stables, where the
larva lives for several days as a white maggot without
feet, then in a week of quiet the pupa changes to the
perfect insect, which buzzes about our houses for a few
weeks more.
The Fly. 109

In the crane-fly the balancers stand out well from the
body, and one can see plainly that their slender stalks are
borne on the last ring of the thorax. The large, high,
second ring of the thorax, the long abdomen and long
wings remind us of the dragon-fly, but the single pair of
wings and the prominent balancers show us it can be
nothing but a fly, even without an examination of the
mouth-parts.

 

The large flies that mimic bees and are common around plants,
are excellent subjects for study after the bee has been taken.
THE BUTTERFLY.

Whatever difficulty they may have in secnring specimens for
other lessons, children can always catch butterflies and caterpillars,
Butterflies may be killed with chloroform or benzine, and the wings
spread on a setting-board made by nailing two cleats lengthwise on
a piece of wood with a space between them wide enough for the
body of the insect. When dried, the butterflies may be pinned in a
box with strips of cork glued inside the bottom. Caterpillara are
put in boxes, fed with fresh leaves, and kept through their trans-
formations, while chrysalids can be gathered in the autumn.

 

Fig. 1.

Cabbage butter flies (Fig. 1) are always plenty, and will do very
well, if larger ones are sot at hand. Specimens for study may be
kept without pinning in boxes or envelopes. Two days before the
lesson they should be placed upon thin paper over wet sand. This
will soften them so that they can be handled without breaking
easily. Butterflies kept in alcohol will be perfectly flexible, bat
will have no bright colors, and children will not feel that they are
the real thing.

The cabbage butterfly has two pairs of very large
wings. They are white with two black spots and a
black patch on the forward ones,and one black spot on

the hind ones.
110
The Butterfly. 111

The male has but one black spot on each fore wing.

If we rub the dust off the wings, they lose their color
and are transparent. When the butterfly rests, it carries
its wings erect over its back. Its body is very small for
its wings. The rings show plainly on the abdomen. The
head and thorax are hairy.

The hairs and scales must be rubbed off in order that che three
regions of the body may be clearly seen.

The butterfly has a pair of antenne shaped like clubs
with long handles. It has two large compound eyes.
It has a long tongue coiled up tightly under its face
(Fig. 2, mat,). It has two little bunches of hairs stand-
ing up in front of its forehead (Figs. 1 and 2, 2?).

Fig. 2 represents the sucking tube and one of the palpi of the
monarch or milk-weed butterfly.

t

      
   
  

     
     
   
 

mx
(|| Ve eaein

: v (" \ a) . | _

; mah pdt he igi
Fig. 2 Fig. 8

The two “bunches of hairs” are the palpi belonging
to the second pair of maxilla. Though these maxille
are either obsolete or very minute in butterflies, their
palpi form two large hairy cushions, between which rests
the coiled tongue or sucking tube, (Fig. 2, mx). The
Jatter is the greatly lengthened first maxille, their edges
112 Lessons in Zodlogy.

united to form a closed tube, through which the honey of
the flowers is carried to the mouth. Mandibles are of no
use and extremely minute, if present at all.

After the scales are rubbed off, the children draw the wings, no-
ticing the long veins evenly distributed over them. Such a wing
cannot give a strong downward stroke, hence the fluttering of the
butterfly. If a microscope can be procured, a bit of a wing with
some of the acales still on it may now be shown (Fig. 3), each child
looking at it in turn while the others draw.

The butterfly’s legs are small and weak, because but
little used.

b.
my Ce aS
Fig. 4. Fig. 5. Fig. 6.

The caterpillar of the cabbage butterfly (Fig. 4) has a
long, greenish bedy. The rings of the thorax are like
those of the abdomen. The legs on the thorax are very
small and end in little claws. There are five pairs of
legs on the abdomen ending in broad cushions. The
breathing holes show very plainly on the abdomen. Since
the caterpillar feeds on leaves, it has strong mandibles
for biting.

In its winter sleep in the chrysalis the caterpillar is
transformed into a butterfly. It prepares for the change
by seeking the under side of some fence rail (Fig. 4), fix-
ing itself by its tail, and spinning a strong silken band
around the middle of its body to hold it in place (Fig. 5).
In its firm chrysalis skin (Fig. 6) it defies Jack Frost,
and comes out in the spring a perfect butterfly.
THE MOTH.

This leason may be made intensely interesting by using large
moths and butterflies and comparing them at every step. It is
not necessary that all the butterflies or all the moths should belong
to the same species. The common milkweed butterfly, Danais
Archippus (Fig. 1), or the large yellow and black swallow-tail,
Papilio Turnus, will be excell-nt in comparison with the American
silkworm moth, Telea Polyphemus (Fig. 2), or either of the large
moths somewhat resembling it. If some of the class have hawk-
moths (Fig. 6), it will be all the better, especially if they can tell
from their own observation that these are more rapid fliers than the
others, and thus see the use of the longer, more pointed, and more
powerful fore wings and the small hind wings working with them.
The Polyphemus is here taken first as the basis of the leason.

 

Fig. 1.

The body of the moth is broader and stronger than
that of the butterfly. It has a thicker coating of hair.
The wings are larger and not so brightly colored. The

 

+ From Hyatt’s Insecta; D. C. Heath & Co., publishers, Boston.
113
114 Lessons in Zvilogy.

 

Fig. 2.+

 

+t From Hyatt’s Insecta ; D. C. Heath & Co., publishers, Boston.
The Moth. 115

antennz are not shaped like clubs, but are feathered. The
mouth-parts are so small that nothing but thick cushions
of soft hairs can be seen on the under side of the head.

This moth probably lives but a short time and eats little, since it
can only lap up its food,

 

Fig. 3.

Most moths fly at twilight or in the night, while butter-
flies fly by day. When moths are at rest, their wings
form a sloping roof over the body.

The Polyphemus moth generally lays its eggs on oak
leaves. The huge caterpillar (Fig. 3) is bright green
without yellow stripes or bands, but with rows of hairy
warts, and an oblique white line on the side of each ring.
Its head and feet are brown, and the tail is bordered by
a brown V-shaped line. It makes a beautiful cocoon of
glossy silken threads covered on the outside with leaves
(Fig. 4), in which it safely passes the winter. When the
leaves fall in the autumn, the tough oval cocoon enclosed
in them is borne to the ground. If one of these cocoons
is opened, the pupa looks as in Fig. 5. Its body is much
shorter than that of the caterpillar and covered with a

+ From Hyatt’s Insecta; D.C. Heath & Co., ‘pabueners, Boston.

 
116 Lessons in Zoilogy.

hard brown skin. The wings and antennz are glued to
the under side of the body, and the breathing-holes show
plainly on the sides of the rings. The moth comes out
during May in Massachusetts. When the time comes
for it to leave the cocoon, by means of an acid liquid it
dissolves the gum that holds the silken threads together
and then emerges without breaking the,silk. Inside may
be found the pupa-skin it has left behind.

 

The hawk-moth (Fig. 6) has no bright-colored spots
or markings. Its antennz are not feathered and end in
a small hook. Its sucking-tube is very long, so that it
can reach the honey in long-tubed flowers. By scraping
the hairs and scales from the under side of the wings, the
little hook or bristle on the hind wing and the ring
through which it passes on the fore wing can be seen.

 

An interesting observation for pupils in the country is to watch
this moth at twilight as it poises on its quivering wings over some
large flower and thrusts its aucking-tube down to its base. From
The Moth. 117

 

Fig 6 +

 

+ From Hyatt’s /nsecta ; D. C. Heath & Co., publishers, Boston.
118 Lessons in Zovlogy.

its imitating the motions of the humming-bird in this way, it is
often called the homming-bird moth.

    

  
    
    

|

ANS
if RL eu

Fig. 7. t

Pa
Ot

The caterpillars of the large moths are all enormous
eaters, and many of them are the great green “ worms,”
so called. The “potato worm” (Fig. 7),—found also on
tobacco and the tomato,—is the larva of the hawk-moth
shown in Fig. 6. This larva will often remain for some
time motionless on a stem with the head and front part of
the body stretched upward, and from this habit the moths
are named the Sphinxes.

+ From Hyatt’s Jnsecta; D.C. Heath & Co , publishers, Boston.
THE BEE.

Lesson I.

Of course we choose the honey-bee (Fig. 1) for this lesson.
With » wide-mouthed bottle partly filled with dilute alcohol we
take our stand beside a clump of tall plants in blossom, and in a
single morning capture bees enough fora large class. When the
busy little brown-cosated worker has its head well buried in the
flower, it is easy to place the bottle under the mouth of the flower
and with the cork press the bee down into it. Only the knowledge
that in no other way can we become acquainted with the structure
of these little creatures reconciles us, however, to the murder of
these industrious and useful insects.

 

The head and thorax are thickly covered with hairs.
The body is short and strong. The three divisions of the
body are plainly seen. The abdomen is connected with
the thorax by a small joint. There are two pairs of
wings, but the hind wings are so small and fit so closely
to the edge of the fore wings that when they are spread
they look like a single pair.

The hind legs (Fig. 2) are longer than the others, and
the upper section of the foot (Fig. 2, f) is very broad.
The lower section of the leg (Fig. 2, 1) is concave on the

inner side and surrounded by long hairs. Thelargesection
119
12u Lessons in Zodlogy.

of the foot has several rows of stiff hairs across it. These
broad joints are the “pollen baskets” in which pollen
from the flowers is carried to the hive to be made into
bee-bread for the babies. The foot ends in two claws.

 

Fig. 2,

The few strong veins at the base and on the front margin of the
wings enable them, though amall, to strike the air with great force.
The two wings on each side are so united by a series of hooks that
they work together perfectly.

The antenne (Fig. 3, at) are short. The compound
eyes (Fig. 3, ey) are large. The bee has a pair of hard,
brown mandibles (Fig. 3, md). Two pairs of light brown
mouth-parts pointed at the end hang
down below the mouth, besides a larger
piece that looks like a tongue.

-al

 

Fig. 3.

The shape of the head is one mark that distinguishes the bees
from those flies that mimic them so well. In the fly the eyes
The Bee. 121

always project further from the head. But if the difference in the
shape of the head is not marked enough, the single pair of wings
and the balancers of the fly will tell the story.

In the various insects we have studied we have seen
mouth-parts for biting, for piercing, and for sucking, but
here we find a combination of them all in one insect.
The hard mandibles (Fig. 3. md) are perfect little organs
for biting and cutting ; the first maxille (Fig. 4, ma.) are
long, sharp blades for piercing flowers; the middle por-
tion of the second maxillz (Fig. 4, Jy) is the long sucking-

“A q
‘

      
 

   
 

whe

MA
LZ

  

tube for gathering the nectar, the longest of all the mouth
parts; and on either side of it is a long palp or feeler (x”),
ending in tiny joints and reminding one of a brown
needle. The best way to see the form and use of these
parts is to capture a large bumble-bee and feed it with a
syrup made of sugar and water.
122 Lessons in Zodlogy.

The three simple eyes (Fig. 3, oc) do not show on alcoholie apec-
imens unless they are allowed to dry, but are prominent on the
liviug insect.

The sting is the egg-layer changed into a powerful
weapon.

This lesson should be given in summer or early autumn, that the
best part of it may be the observation of the living inaect. We can
follow single bees and eee with what persistent industry they try all
the flowers of one kind, paying not the slightest heed to any others,
but so intent upon their work that it is easy to make them prison-
ers when once the sucking-tube is buried ina flower. Not the most
brilliant buttercup can entice them if it is clover-honey that they
are in search of. It has been proved beyond a doubt that bees can
distinguish colors, and Sir John Lubbock decides, as the result of
his experiments, that their favorite is d/ue.

Lesson IT.

Some honey and a piece of the comb consisting of worker cella,
drone cells, avd a single royal cell; a queen bee and a drone, each
in its vial of alcohol, and a few of the little worm-like larvae in an-
other vial, — these constitute a perfect equipment for our second
leagon on the bee. By making arrangements with a bee-keeper
some months in advance, one may hope to secure all these, if she is
fortunate.

 

Fig. 1.

Many insects make homes for themselves or for their
young. Caterpillars roll up leaves ; the young clothes-moth
hides itself in a case of fibers from our softest woolen
The Bee. 123

dresses ; the caddis-worm glues together a movable for-
tress of sticks and stones or a mossy covering of leaves,
in which it conceals its greedy appetite and ugly jaws ;
and many kinds of bees and wasps tunnel stems or burrow
in the earth, but one of the most remarkable insect homes
is the honeycomb of the hive bee. Before examining the
home, however, we must make the acquaintance of the
other members of the family.

 

Fig. 2.

We have studied only the workers; but every colony
must also have a queen, and during part of the summer,
some drones. The queen, or mother bee, does nothing
but lay eggs, sometimes as many as two or three thousand
in a day. The drones, or males, do absolutely no work.
The workers build the combs, gather the honey and
pollen, act as nurses for the young, and attendants upon
the queen.

We examine first the queen, then the drone, noting only distin-

guishing characteristics of each as compared with the workers,
afterward observing the cells of the comb.

The queen is larger than the worker. Her head is
124 Lessons in Zoilogy.

narrower than the thorax. The wings are shorter than
the body of the queen. The lower joint of her hind
legs is flat and has no fringe of hairs around it. It could
not be used for a pollen basket.

This bee is a male, called a drone because he does no
work. His head is narrower than the thorax, like the
queen bee’s. His eyes are not at all like the queen’s or
the worker’s but meet on the top of his head, like a fly’s.
His wings are longer than his body. He has no pollen
basket, but a very large upper joint on each hind foot.

 

oe
Fig. 3. big. 5.

A colony may contain from twenty thousand to fifty
thousand workers, and in summer from one thousand
to two thousand drones, but never more than one queen
at atime. When a new queen comes out of her cell, the
bees “swarm,” that is, the old queen leads a part of them
away to form another colony. Or, if two queens do
escape from their cells at the same time, a duel takes
place which ends only with the death of one of the rivals.
The Bee. 125

In taking possession of a new hive they cling to one
another in living festoons from the roof, while the wax
forms in little plates under the edge of each ring of the
abdomen. (Fig. 2.) These plates they take off with
their feet, work them with their mandibles, and stick
them to the roof of the hive till a shapeless mass of wax
is formed. Then other bees hollow out the cells in the
wax.

Fig. 1 represents the magnified head of each of the three differ-
ent forms of the honey-bee; a, the queen, 6, the worker, ¢, the
drone, showing the great development of the mouth-parts in the
worker and their very small size in the drone; also the differing
shape of the face in queen and worker, as well as the enormous
eyes of the male and the shortness of his antenne above the bend.

Fig. 2 is a magnified view of a bee with the plates of wax show-
ing between the rings of the abdomen.

In this piece of comb there are three kinds of cells;
Small cells in rows, !arger ones in rows, and a lorg one
at the edge of the others. The cells in the rows are six-
sided; the long one is shaped something like a peanut.
The small cells (Fig. 3, c) are for the smallest bees, the
workers ; the larger ones (5) are for the drones ; and the
long cell (a) is for the queen. So few queens are pro-
duced every year that only a very few royal cells are
needed. There are also storage cells for honey, which are
sealed up with wax so as to be air-tight and keep the honey
in its natural condition.

The larva (Fig. 4) is a tiny white worm, without feet,
perfectly helpless, and entirely dependent upon its faithful
nurses. In five or six days it reaches its full size, and
covers itself with a thin cocoon. After ten days of pupa
life (Fig. 5) it emerges from its cell, a perfect insect.
THE ANT.

The large black ant, that makes its nests in trees and may be
seen around the outside of our houses, can often be easily collected
in large numbers. The winged females (Fig. 1), appearing with
the winged males (Fig. 2) in summer, are especially large, and the
workers and soldierg make very good specimens.

 

Fig. 1.

No better introduction to this Jesson cao be desired than to find
an ant’s nest in some rotten atamp where the decaying bark and
wood on the outside may be easily broken off, revealing the
chambers within. What hurrying and scurrying as the anta rush
back and forth carrying cocoons and helpless little grabs to safe
retreata in the center of the nest! Utterly regardless of self and
apparently incapable of fatigue, they will work for hours, if neces-
sary, to place every one of their helpless charges under shelter.
How they will tug and pull to reacue a cocoon that has been pin-
ioned by a falling timber in the shape of a chip! How carefully

126
The Ant. 127

they pick up the grubs with their sharp jaws, handli
skillfully that the soft little creatures as oe ed ieee
they feel responsible for their charges or not, nothing could exceed
the faithfulness of their care.

Our specimens are chiefly the common wingless forms,—workerg
(Fig. 8) and soldiers (Fig. 4). Placing these two kinds side by
side, these observations will be made : —

 

Fig. 2. Fig. 3.

The ant has no wings. Some of the ants have enor-
mous heads. The head looks nearly as large as the
abdomen. The thorax is very long and narrow. I can
see the three rings of the thorax and a pair of legs on
each ring. The abdomen can be curled up under the
thorax. The jaws are very large. Two of the ants are
all snarled up together; they have caught hold of each
other’s legs with their jaws, and it is almost impossible to
pull them apart. Some of them are larger than the
others, with longer bodies, larger heads, and stronger
jaws.

As is shown by the figures, the soldiers are the larger forms.
Their mandibles are enormously developed for use as weapons.
Though the jaws of the workers are smaller, they are very strong,
the ants carrying with them objects even larger than themselves

for considerable distances.
Carefal examination of the stem, or pedunole, joining the thorax
128 Lessons in Zodlogy.

to the abdomen, shows that in this ant it consists of two joints,
making the abdomen more flexible and capable of being used with
greater force in atinging.

The antennz are bent near the middle. The head is
longer and more pointed thanthe bee’s, and the eyes
are small. The head is triangular.

 

Fig. 4. Fig. 5.

The males and females have three simple eyes (Figs. 1 and 2);
the workers and soldiers have only the compound eyes. To see the
mouth-parts remove the bead from the body and hold it firmly,
with sharp-pointed forceps, under a dissecting microscope, then
with a needle pry apart the mandibles and carefully separate the
parts below them from the head. The soft mass thus removed will
be found to consist of a pair of broad, lesf-like first maxilla, with
long palpi, and the united second maxillz, also with long palpi and
with their inner side forming a thick, soft tongue. These parts
can be glued toa card. This dissection is too difficult for children,
however.

A few winged males and females should be shown, and the large
size of the female noticed. The males die after the marriage
flight, and the females pull off their own wings and settle down to
a quiet life of several years, perhaps, in the nest. Sir John
Labbock had two queens that lived for seven years, and some of
his workers lived six years.

The larve are small white grubs (Fig. 5), without legs,
and so helpless that they cannot even feed themselves.
They are dependent upon their nurses till they are full-
The Ant. 129

grown, for many of them would die in the attempt to
free themselves from their cocoons if not assisted by the
older ants.

There is almost no limit to the number of interesting facts about
ants that we can gather from such books as Sir John Lubbock’s
Ants, Bees, and Wasps, Mrs. Treat's Chapters on Ants, and
McCook’s Agricultural Ant of Texas. A few carefully chosen
facta from such books, given to pupils after the observation lesson,

will make them more eager to watch ants for discoveries of
their own.
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