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Digitized by the Internet Archive
in 2008 with funding from
Microsoft Corporation

http://www.archive.org/details/beginnerszoologyOOcoleuoft

BEGINNERS’ ZOOLOGY

BY
WALTER M. COLEMAN

AUTHORIZED BY THE MINISTER OF EDUCATION
FOR ONTARIO

TORONTO
THE MACMILLAN CO. OF CANADA, LIMITED
1921

Copyright, Canada, 1921
BY THE MACMILLAN COMPANY
OF CANADA, LIMITED

2535

CONTENTS
CHAPTER

I, INTRODUCTION

II, PrRoTOZOANS
III. SPonceEs

LV POLYPS: ~

V. ECHINODERMS

VI. Worms.
VII. CRUSTACEANS
VIII. Insects

IX. Mo .tuscs

X, -LISHES' ~.

XI. BATRACHIANS
XII. REPTILES
XIII. Birps
XIV. MammMats

109
126
139
150
184

BEGINNERS’ ZOOLOGY

CHAPTER I
THE PRINCIPLES OF BIOLOGY

Brotocy (Greek, dzos, life; /ogos, discourse) means the
science of life. It treats of animals and plants. That
branch of biology which-treats of animals is called zoology
(Gr. goon, animal; Jogos, discourse). The biological
science of botany (Gr. botane, plant or herb) treats of
plants.

Living things are distinguished from the not living by a
series of processes, or changes (feeding, growth, develop-
ment, multiplication, etc.), which together constitute what
is called life. These processes are called fusctions. Both
plants and animals have certain parts called organs which
yave each a definite work, or function; hence animals and
plants are said to be organized. For example, men and

most other animals have a certain organ (the mouth) for
taking in nourishment; another (the food tube), for its
digestion.

Because of its ovgantzation, each animal or plant is said
to be an crganism. Living things constitute the organic
kingdom. Things without life and not formed by life
constitute the zzorganic, or mineral, kingdom. Mark I for
inorganic and O for organic after the proper words in this
list: granite, sugar, lumber, gold, shellac, sand, coal, paper,
glass, starch, copper, gelatine, cloth, air, potatoes, alcohol,
oil, clay. Which of these things are used for food by
animals? Conclusion?

B I

Z BEGINNERS” ZOOLOGY

Energy in the Organic World. — We see animals exerting
energy; that is, we see them moving about and doing
work. Plants are never seen acting that way; yet they
need energy in order to form their tissues, grow, and raise
themselves in the air.

Source of Plant Energy. — We notice that green plants
thrive only in the light, while animal growth is largely in-
dependent of light. In fact, in the salt mines of Poland
there are churches and villages below the ground, and
children are born, become adults, and live all their lives
below ground, without seeing the sun. (That these people
are not very strong is doubtless due more to want of fresh
air and other causes than to want of sunlight.)

a an The need of plants for
. Fee 42 sunlight shows that they

2 ¢ > ree nf
Fal ' ae must obtain something

+ - Sona
aw Ww j a "
nee ee US UL Jrom the sun. This has
Fic. 1.—SURFACFS OF A LEAF, been found to be energy.
agnified,
es This enables them to Zt

their stems in growth, and form the various structures
called t’sswes which make up their stems and _ leaves.
It is noticed that they take in ,
food and water from the soil
through their roots. Experiments
also show that green plants take
in through pores (Fig. 1), on the
surface of their leaves, a gas
composed of carbon and oxygen,
and called carbon dioxide. The
energy in the sunlight enables the
plant to separate out the carbon,
of the carbon dioxide and to build
mineral and water and carbon

d Gas
in the Air going
into the Leaf

FIG. 2. —A LEAF STORING

ENERGY IN SUNLIGHT.

THE PRINCIPLES OF BIOLOGY 3

into organic substances. The oxygen of the carbon dioxide
is set free and returns to the air (Fig. 2). Starch, sugar,
oil, and woody fibre are examples of substances thus
formed. Can you think of any fuel not due to plants?
How Animals obtain Energy. — You have noticed that
starch, oil, etc., will durnz, or ortdize, that is, wuzte with the
oxygen of the air; thus the sun’s energy, stored in these
substances, is changed back to heat and motion. The
oxidation of oil or sugar may occur in a furnace; it may
also occur in the living substance of the active animal.

Fic. 3—Cotour.ess plants,as MusH- A GREEN LEAF, even after it is cut, gives
ROOMS, give off no oxygen. off oxygen (O) if kept in the sun.

Fortunately for the animals, the plants oxidize very little
of the substances built up by them, since they do not move
about nor need to keep themselves warm. We notice that
animals are constantly using plant substances for food, and
constantly drawing the air into their bodies. If the sun-
light had not enabled the green plant to store up these
substances and to set free the oxygen (Fig. 3), animals
would have no food to eat nor air to breathe; hence we
may say that the sunlight is indirectly the source of the
life and energy of animals. Mushrooms and other plants
without green matter cannot set oxygen free (Fig. 3).

4 BEGINNERS’ ZOOLOGY

Experiment to show the Cause of Burning, or Oxidation.
— Obtain a large glass bottle (a pickle jar), a short candle,
and some matches. Light the candle and put it on a table
near the edge, and cover it with the glass jar. The flame
slowly smothers and goes out. Why is this? Is the air
now in the jar different from that which was in it before
the candle was lighted? Some change must have taken
place or the candle would continue to burn. To try
whether the candle will burn again under the jar without
changing the air, slide the jar to the edge of the table and
let the candle drop out. Light the candle and slip it up
into the jar again, the jar being held with its mouth a little
over the edge of the table to receive the candle (Fig. 5).
The flame goes out at once. Evidently the air in the jar
is not the same as the air outside. Take up the jar and
wave it to and fro a few times, so as to remove the old air
and admit fresh air. The candle now burns in it with as
bright a flame as at first. So we conclude that the candle
will not continue to burn unless there is a constant supply
of fresh air. The gas formed by the burning is carbon
dioxide. It is the gas from which plants extract carbon.‘
(Beginners’ Botany, Chap. XIII.) One test for the presence
of this gas is that it forms a white, chalky cloud in lime
water; another is that it smothers a fire.

Experiment to show thatAnimals give cff Carbon Dioxide.
— Place a cardboard over the mouth of a bottle containing
pure air. Take a long straw, the hollow stem of a weed,
a glass tube, or a sheet of stiff paper rolled into a tube,
and pass the tube into the bottle through a hole in the
cardboard. Without drawing in a deep breath, send one
long breath into the bottle through the tube, emptying the
lungs by the breath as nearly as possible (Fig. 4). Next,
invert the bottle on the table as in the former experiment,

THE PRINCIPLES OF BIOLOGY 5

* afterward withdrawing the cardboard. Move the bottle
to the edge of the table and pass the lighted candle up
into it (Fig. 5). Does the flame go out as quickly as
in the former experiment ?

If you breathe through a tube into clear lime water,
the water turns milky. The effect of the breath on the
candle and on the lime water shows that carbon dioxide is
continually leaving our bodies in the breath.

FIG. 4. — Breathing into a bottle.1 FIG, 5.— Testing the air in the bottle.

Oxidation and Deoxidation. — The union of oxygen with
carbon and other substances, which occurs in fires and
in the bodies of animals, is called oxidation. The separa-
tion of the oxygen from carbon such as occurs in the
leaves of plants is called deoxzdation. The first process
sets energy free, the other process stores it up. Animals
give off carbon dioxide from their lungs or gills, and plants
give off oxygen from their leaves. But plants need some
energy in growing, so oxidation also occurs in plants, but
to a far less extent than in animals. At night, because
of the absence of sunlight, no deoxidation is taking place

6 BEGINNERS’ ZOOLOGY

in the plant, but oxidation and growth continue; so af
night the plant actually breathes oui some carbon dioxide.
The deepest part of the lungs contains the most carbon
dioxide. Why was it necessary to empty the lungs as
nearly as possible in the experiment with the candle? Why
would first drawing a deep breath interfere with the experi-
ment? Why does closing the draught of a stove, thus
shutting off part of the air, lessen the burning? Why does
a “firefly” shine brighter at each breath? Why is the pulse
and breathing faster in a fever?’ Very slow in a trance?

The key for understanding any animal is to find /ow
zt gets food and oxygen, and how it uses the energy
thus obtained to grow, move, avoid its enemies, and get
more food. Because it moves, it needs senses to guide it.

The key for understanding a plant is to find Low z¢ gers
food and sunlight for its growth. It makes little provision
against enemies; its food is in reach, so it needs no senses
to guide it. The plant is built on the plan of having the
nutritive activities ear the surface (e.g. absorption by roots ;
gas exchange in leaves). The animal is built on the plan
of having its nutritive activities on the znside (e.g. digestion ;
breathing).

Cell and Protoplasm.— Both plants and animals are
composed of small parts called ce//s. Cells are usually
microscopic in size. They have various shapes, as spheri-
cal, flat, cylindrical, fibre-like, star-shaped. The living
substance of cells is called protoplasm. It is a stiff, gluey
fluid, a/duminous in its nature. Every cell has a denser
spot or kernel called a wacleuws, and in the nucleus is a still
smaller speck called a xzcleolus. Most cells are denser and
tougher on the outside, and are said to have a cel/ wall,
but many cells are naked, or without a wall. Hence the
indispensable part of a cell is not the wall but the nucleus,

THE PRINCIPLES OF BIOLOGY 7

and a cell may be defined as a bit of protoplasm containing
a nucleus. This definition includes naked cells as well as
cells with walls.

One-celled Animals. -— There are countless millions of
animals and plants the existence of which was not sus-
pected until the invention of the micro-
scope several centuries ago. They are
one-celled, and hence microscopic in size.
It is believed that the large animals and
plants are descended from one-celled ani-
mals and plants. In fact, each individual

Fic. 6.— Egg cell of

plant or animal begins life as a single vate,

cell, called an eggcell, and forms its
organs by the subdivision of the egg cell into many cells.
An egg cell is shown in Fig. 6, and the first stages in the
development of an egg cell are shown in Fig. 7.

The animals to be studied in the first chapter are one-
celled animals. To understand them we must learn how

FIG. 7. — Egg cell subdivides into many cells forming a sphere (morula) containing
a liquid. A dimple forms and deepens to form the next stage (gastrula).

they eat, breathe, feel, and move. They are called Pro-
tozoans (Greek frotos, first, and zoov). All other animals
are composed of many cells and are called MMefazoans
(Greek meta, beyond or after). The cells composing the
mucous membrane in man are shown in Fig. 8. The cellu-
lar structure of the leaf of a many-celled plant is illustrated
in Fig. 1.

8: BEGINNERS’ ZOOLOGY

Method of Classifying Animals. — The various animals
display differences more or less marked. The question
arises, are not some of them more closely related than
others? We conclude that they are, since the differ-
ence between some animals is very slight, while the
difference between others is quite marked.

To show ¢he different steps in classi-
Jying an animal, we will take an ex-
ample, —the cow. Even little children
learn to recognize a cow, although indi-
vidual cows differ somewhat in form,
size, colour, etc. The varieties of cows,
such as short-horn, Jersey, etc., all
form one sfeczes of animals, having the
scientific name ¢aurus. Let us include
in a larger group the animals closest
akin to a cow. We see a Cat, a bisor,
and a dog; rejecting the cat and the
dog, we see that the bison has horns,
hoofs, and other similarities. We in-
Fic. 8.—Mucous Mem. Clude it with the cow in a genus called

BRANE formed ofone fos, calling the cow Bos taurus, and

layer of cells. A few ; .

cella secrete mucus. , tHe bison; Bos bison. “Pheysaered cow

of India (Bos indicus) is so like the
cow and the buffalo as also to belong to the genus Bos.
Why is not the came), which, like Bos bison, has a hump,
placed in the genus Bog?

The Old World buffaloes, — most abundant in Africa
and India, —the antelopes, sheep, goats, and several other
genera are placed with the genus Bos in a famzly called
the hollow-horned animals.

This family, because of its even number of toes and
the habit of chewing the cud, resembles the camel family,

THE PRINCIPLES OF BIOLOGY 9

the deer family, and several other families. These are all
placed together in the next higher systematic unit called
an order, in this case, the order of ruminants.

The ruminants, because they are covered with hair
and nourish the young with milk, are in every essential
respect related to the one-toed horses, the beasts of
prey, the apes, etc. Hence they are all placed in a
more inclusive division of animals, the class called
mammals.

All mammals have the skeleton, or support of the
body, on the inside, thé axis of which is called the verte-
bral column. This feature also belongs to the classes
of reptiles, amphibians, and fishes. It is therefore
consistent to unite these classes by a general idea or
conception into a great drvanch of animals called the
vertebrates.

Returning from the general to the particular by succes-
sive steps, state the branch, class, order, family, genus,
and species to which the cow belongs.

The Eight Branches or Sub-kingdoms. — The simplest
classification divides the whole animal kingdom into
eight branches, named and characterized as follows, be-
ginning with the lowest: I. Protozoans. One-celled.
II. Sponces. Many openings. III. Poryps. Circular;
cup-like; having only one opening which is both mouth and
vent. IV. EcHINopDERMS. Circular; rough-skinned; two
openings. WV. Moxtuscs. No skeleton; usually with ex-
ternalshell. VI. VERmMEs. Elongate body, no jointed legs.
VII. ArtTHROoPoDs. External jointed skeleton; jointed
legs. VIII. VERTEBRATES. Internal jointed skeleton with
axis or backbone.

1 This is the briefest classification. Animals have also been divided into twelve
branches. The naming of animals is somewhat chaotic at present, but an attempt
to come to an agreement is now being made by zodlogists of all nations.

CHAPTER If
PROTOZOA (One-celled Animals)
THE AMG@BA

SUGGESTIONS. — Ameebas live in the slime found on submerged
stems and leaves in standing water, or in the ooze at the bottom.
Water plants may be crowded into a glass dish and allowed to
decay, and after about two weeks the amaba may be found in
the brown slime scraped from the plants. An amceba culture

sometimes lasts only three days. The most abundant supply
ever used by the writer was from a bottle of water where some
oats were germinating. Use 4 or + inch objective, and cover
with a thin cover glass. Teachers who object to the use of
the compound microscope in a first course should require a
most careful study of the figures.

Fic. 9—AMa@:BA PROTENS, much enlarged.

10

PROTOZOA If

Form and Structure. — The ameeba looks so much like
a clear drop of jelly that a
beginner cannot be certain
that he has found one until
it moves. It is a speck of
protoplasm (Fig. 9), with a
clear outer layer, the ecto-
flasm; and a granular, in-
ternal part, the endop’asm.
Is there a distinct line be-
tween them? (Fig. 10.)

PS,
Fic. 10.—AMG@BA.

Note the central portion cv, contractile vacuole; ec, ectoplasm; ez,
endoplasm; x, nucleus; fs, pseudopod;
and the slender prolonga- ps , pseudopod forming; ectoplasm pro-
tions or pseudopods (Greek, trudes and endoplasm flows into it.
false feet). Does the endoplasm extend into the pseudo-
pods? (Fig. 10.) Are the pseudopods arranged with any
regularity ?

Sometimes it is possible to see a denser appearing por-
tion, called the zzcleus ; also a clear space, the contractile
vacuole (Fig. 10).

Movements. —— Sometimes while the pseudopods are be-
ing extended and contracted, the central portion remains
in the same place (this is mo-
tion). Usually only one pseudo-
pod is extended, and the body
flows into it; this is /ocomotion

Fic. 11.—The same amceba seen (Fig. LE); There is a new foot
at different times. 5
made for each step.
Feeding.—If the amceba crawls near a food particle, the
pseudopod is pressed against it, or a depression occurs (Fig.
12), and the particle is soon embedded in the endoplasm.
Often a clear space called a food vacuole is noticed around

the food particle. This is the water that is taken in with

12

Fic. 12. — THe
Ama@sa taking
food.

BEGINNERS’ ZOOLOGY

the particle (Fig. 12). The water and the
particle are soon absorbed and assimilated
by the endoplasm.

Excretion. — If a particle of sand or other
indigestible matter is taken in, z¢ zs left behind
as the amoeba moves on. There is a clear
space called the contractile vacuole, which
slowly contracts and disappears, then reap-
pears and expands (Figs. 9 and 10). This
possibly aids in excreting oxidized or useless
material.

Circulation in the amceba consists of the
movement of its protoplasmic particles. It
lacks special organs of circulation.

Feeling.—Jarring the glass slide seems to
be felt, for it causes the activity of the amceba
to vary. It does not take in for food every
particle that it touches. This may be the
beginning of taste, based upon mere chemical
affinity. The pseudopods aid in feeling.

Reproduction. —Sometimes an amceba is
seen dividing into two parts. A narrowing
takes place in the middle; the nucleus also
divides, a part going to each portion (Fig. 13).

The mother ameceba finally divides into two daughter
ameoebas. Sex is wanting.

Source of the Amoeba’s Energy —We thus see that the
amceba moves without feet, eats without a mouth, digests

without a stomach, feels
without nerves, and, it
should also be stated,
breathes without lungs,

for oxygen

7s absorbed

from the water dy zts whole Wig: 18 --Aueend Divides

PROTOZOA 13

surface. Its movements require energy ; this, as in all ani-
mals, is furnished by the wnzting of oxygen with the food.
Carbon dioxide. and other waste products are formed
by the union;these pass off at the surface of the amoeba ard
taint the water with impurities.

Questions.— Why will the ameeba die in 2 very small quantity of
water, even though the water contains enough food? Why will it die
still quicker if air is excluded from contact with the drop of water?

The ameeba never dies of old age. Can it be said to beimmortal?

According to the definition of a cell (Chapter I), is the amoeba a
unicellular or multicellular animal?

Cysts. — If the water inhabited by a protozoan dries up,
it encysts, that is, it forms a tough skin called a cyst.
Upon return of better conditions it breaks the cyst and
comes out. Encysted protozoans may be blown through
the air: this explains their appearance in vessels of water
containing suitable food but previously free from proto-
zoans.

THE SLIPPER ANIMALCULE OR PARAMECIUM

SUGGESTIONS.—Stagnant water often contains the paramecium as
well as the ameeba; or they may be found in a dish of water cone
taining hay or finely cut clover, after the dish has been allowed to
stand in the sun for several days. A white film forming on the
surface is a sign of their presence. They may even be seen with
the unaided eye as tiny white particles by looking through the side
of the dish or jar. Use at first a } or } in. objective. Restrict
their movements by placing cotton fibres beneath the cover glass ;
then examine with + or 1 objective. Otherwise, study figures.

Shape and Structure. — The paramecium’s whole body,
like the amceba’s, is only one cell. It resembles a slipper
in shape, but the pointed end is the hind end, the front end
being rounded (Fig. 14). The paramecium is propelled
by the rapid beating of numerous fine, threadlike append-

14 BEGINNERS’ ZOOLOGY

ages on its surface, called cz/ia (Latin, eyelashes) (Figs.).
The cilia, like the pseudopods of the amceba, are merely
prolongations of the cell protoplasm,

but they are permanent. The sepa-
ration between the outer ectoplasm
and the interior granular exdoplasm
is more marked than in the amceba

FIG. 14.— PARAMECIUM,
showing cilia, c.

Two contractile vacuoles, cv;
the macronucleus, mg;
two micronuclei, #7; the
gullet (@), a food ball
forming and ten food balls
in their course from gullet
to vent, @.

(Fig. 14).

Nucleus and Vacuoles. —- There is
a large nucleus called the macro-

nucleus, and beside it a
smaller one called the
micronucleus. They are
hard to see. About one
third of the way from
each end is a clear, pul-
sating space (bb. Fig.
15) called the pulsat-
ing vacuole. These
spaces contract until
they disappear, and then
reappear, gradually ex-

panding. Tubes lead from the vacuoles which probably
serve to keep the contents of the cell in circulation.
Feeding. — A depression, or groove, is seen on one side;

this serves as a mouth (Figs. ).

Fic. 16,— Two PARAMECIA exchanging

parts of their nuclei.

A tube which serves as a
gullet leads from the
mouth-groove to the in-
terior; of. the cell ihe
mouth-groove is _ lined
with cilia which sweep
food particles inward.
The particles accumulate

PROTOZOA 15

in a mass at the inner end of the gullet, become separated
from it as a food ball (Fig. 14), and sink into the soft pro-
toplasm of the body. The food balls
follow a circular course through the
endoplasm, keeping near the ectoplasm.

Reproduction.— This, as in the ameeba,
is by division, the constriction being in
the middle, and part of the nucleus going
to each half. Sometimes two individ-
uals come together with their
mouth-grooves touching and
exchange parts of their nuclei
(Fig. 16). They then separate - a
and each divides to form two rig. x. FES

new individuals. CELLA (or bell

animalcule), two

We thus see that the para- seen "ons
mecium, though of only one withdrawn.

cell, zs a@ much more complex and advanced

animal than the ameba. The tiny paddles,
Fic. 18.— or cilia, the mouth-groove, etc., have their
aie special duties similar to the specialized organs
of the many-celled animals to be studied later.

If time and circumstances
allow a prolonged study, sev-
eral additional facts may be
observed by the pupil, e.g.
Does the paramecium swim
with the same end always
foremost, and same_ side
uppermost? Can it move
backwards? Avoid obsta-
cles? Change shape in a

Narrow passage ? Doesrefuse Fic. 19. —SHELL OF A RADIOLARIAN,

16 BEGINNERS’ ZOOLOGY

matter leave the body at any particular place? Trace
movement of the food particles.

Draw the paramecium.

Which has more permanent parts, the ameba or para-
mecium 2? Name two anatomical similarities and three dif-
ferences; four functional similarities and three differences.

The ameeba belongs in the class of protozoans called
Rhizopoda “ root footed.”

Other classes of Protozoans are the /zfusorians (in the
broad sense of the term), which have many waving cilia
(Fig. 17) or one whip-like flagellum (Fig. 18), and the
Foraminifers, which possess a calcareous shell pierced with
holes (Fig. 19). Much chalky limestone has been formed
of their shells. To which class does the paramecium
belong?

Protozoans furnish a large amount of food to the higher

animals.

CHAPTER > Tt

SPONGES

SUGGESTIONS.—In many parts of North America, fresh-water
sponges may,by careful searching, be found growing on rocks and logs
inclear water. They are brown, creamy, or greenish in colour, and re-
semble more a cushion-like plant than an animal. They have a chare
acteristic gritty feel. They soon die after removal to an aquarium.

A number of common small bath sponges may be bought and kept
for use in studying the skeleton of an ocean spcnge. These sponges
should not have large
holes in the bottom; if
so, too much of the
sponge has been cut
away. A piece of marine
sponge preserved in alco-
hol or formalin may be
used for showing the
sponge with its flesh in
place. Microscopic slides
may be used for showing
the spicules.

The small fresh-water
sponge (Fig. 21) lacks
the more or less vase-
like form typical of sponges. It is a rounded mass growing
upon arock or alog. As indicated by the Arrows, where does
water enter the sponge? This
may be tested by putting colour
ing matter in the water near
the living sponge. Where does
the water come out? (Fig. 22.)

FIG. 21. — FRESH-WATER SPONGE.

FIG, 22. — SECTION of fresh-water sponge fe
(enlarged). chambers in its course? Is the

Does it pass through cated

Cc 17

18 BEGINNERS’ ZOOLOGY

surface of the sponge rough or smooth? Do any of the skeletal
spicules show on the surface? (Fig. 21.) Does the sponge thin
out near its edge?

The egg of this sponge is shown in Fig. 23. It escapes from
the parent sponge through the oscu/um, or large outlet. As in

most sponges, the first

stage after the egg is

7 ciliated and free-swim-
ming.

Marine Sponges. —

The grantia (Fig. 24) is

one of the simplest of
marine sponges. What is the shafe of grantia? What is its length
and diameter? How does the free end differ from the fixed end?
Are the spicules projecting from its body few or many?

Where is the oscudum, or large outlet? With what
is this surrounded? The osculum opens from a central
cavity called the cloaca. The canals from the pores
lead to the cloaca.

Buds are sometimes seen growing out from the
sponge near its base. These are young sponges formed
asexually. Later they become detached from the
parent sponge.

Commercial “ Sponge.”’ — What part of the complete
animal remains in the bath sponge? Slow growing
sponges grow more at the top and form tall, simple,
tubular or vase-like animals. ast growing sponges
grow on all sides at once and forma complicated system of canals,
pores, and oscula. Which of these habits of growth do you think
belonged to the bath sponge? Is there a large
hole in the base of your specimen? If so, this
is because the cloaca was reached in trimming
the lower part where it was attached to a rock.
Test the edasticity of the sponge when dry and
when wet by squeezing it. Is it softer when wet
or dry? Is it more elastic when wet or dry?
Fic. 2s.—Plan of How many oscula does your specimen have?

a sponge. How many ixhalent pores to a square inch?

2.
FIG. 23.— Eccs and SPICULES of fresh-water
sponge (enlarged).

FIG. 24.—
Grantia.

SPONGES 19

Using a probe (a wire with knob at end, or small hat pin), try
to trace the canads from the pores to the cavities inside.

Do the fibres of the sponge appear to
interlace, or join, according to any system?
Do you see any fringe-like growths on the
surface which show that new tubes are be-
ginning to form? Was the sponge growing
faster at the top, on the sides, or near the
bottom ?

Burn a bit of the sponge; from the odour,
what would you judge of its composition?
Is the inner cavity more conspicuous in a simple sponge or in a
compound sponge like the bath sponge? Is the bath sponge

ona
FIG, 26. — Bath Sponge.

SSS

x, 28. — Bath Sponge.

branched or lobed? Compare a number of specimens (Figs. 26,
27, 28) and decide whether the common sponge has a typical
shape. What features do their forms
possess in common?

Sponges are divided into “ree classes,
according as their skeletons are flinty
(silicious), limy (calcareous), or horny.

Some of the szicious sponges have
skeletons that resemble spun glass in
their delicacy. Flint is chemically nearly
the same as glass. The skeleton shown
in Fig. 29 is that of a glass sponge which
lives near the Philippine Islands.

The horny sponges do not have spi-
cules in their skeletons, as the flinty and
limy sponges have, but the skeleton

FIG. 29.— Skeleton of a y :
glass sponge. is composed of interweaving fibres of

20 BEGINNERS’ ZOOLOGY

spongin, a durable substance of the same chemical nature as silk
(Figs. 30 and 31).

The “my sponges have skeletons made of numerous spicules of
lime. ‘The three-rayed spicule is the commonest form.

The commercial sponge, seen as 7¢ grows in the ocean, appears
as a roundish mass with a smooth, dark exterior, and having about
the consistency of beef liver. Several large openings (oscula),
from which the water flows, are visible on the upper surface.
Smaller holes (inhalent pores— many of them so small as to be
indistinguishable) are on the sides. If the sponge is disturbed,
the smaller holes, and
perhaps the larger
ones, will close.

The outer layer of
cells serves as a sort
of skin. Since so
much of the sponge
is in contact with
water, most of the
cells do their own
breathing, or absorp-
tion of oxygen and giving off of carbon dioxide. Mutriment is
passed on from the surface cells to nourish the rest of the body.

Reproduction. — Egg-cells and sperm-cells are produced by
certain cells along the canals. The egg-cell, after it is fertilized
by the sperm-cell, begins to divide and form new cells, some of
which possess cilia. ‘The embryo sponge passes out at an oscu-
lum. By the vibration of the cilia, it swims about for a while.
It afterwards settles down with the one end attached to the ocean
floor and remains fixed for the rest of its life. The other end de-
velops oscula. Some of the cilia continue to vibrate and create
currents which bring food and oxygen.

The céZia in many species are found only in cavities called
ciliated chambers. (Figs. 22, 32.) There are no distinct organs
in the sponge and there is very little specialization of cells. The
ciliated cells and the reproductive cells are the only specialized
cells. The sponges were for a long time considered as colonies
of separate one-celled animals classed as protozoans, ‘They are,

Fic. 30.— A horny FIG. 31. — Section
sponge. of horny sponge.

SPONGES 21

without doubt, many-celled animals. If a living sponge is cut
into pieces, each piece will grow and form a complete sponge.
That the sponge is not a colony of one-celled animals, each like
an ameeba, but is a many-celled animal, will be realized by exam-
ining Fig. 32, which shows a bit of sponge highly magnified. A
sponge may be conceived as having developed from a one-celled
animal as follows: Sev-
eral one-celled animals
happened to live side by
side; each possessed a
thread-like flagellum (E,
Fig. 32) or whip-lash for
striking the water. By
lashing the water, they
caused a stronger cur-
rent (Fig. 25) than pro-
tozoans_ living — singly
could cause. ‘Thus they
obtained more food and
multiplied more rapidly
than those living alone.
The habit of working
together left its impress

FIG. 32.— Microscopic plan of ciliated chamber.

on the cells and was trans- Each cell lining the chamber has a nucleus,
mitted by inheritance. a whip-lash, and a collar around base of
Cell joined to cell whip-lash. (Qwestion: State two uses of

: : hip-lash.
formed a ring; ring eee

joined to ring formed a tube which was still more effective than
a ring in lashing the water into a current and bringing fresh food
(particles of dead plants and animals) and oxygen.

Few animals eat sponges; possibly because spicules, or fibres,
are found throughout the flesh, or because the taste and the odour are
unpleasant enough to protect them. Small animals sometimes
crawl into sponges to hide. One sponge grows upon shells in-
habited by hermit crabs. Moving of the shell from place to place
is an advantage to the sponge, while the sponge conceals and thus
protects the crab.

Special Report: Songe “ Fisheries.” (Localities ; how sponges
are taken, cleaned, dried, shipped, and sold.)

CHAPTER LY,
POLYPS (CUPLIKE ANIMALS)

Tue Hypra, OR FRESH- WATER POLYP

Succrstions. — Except in the drier regions of North America
the hydra can usually be found by careful search in fresh-water ponds
not too stagnant. It is found attached to stones, sticks, or leaves,
and has a slender, cylindrical body from a quarter to half an
: inch long, varying in thickness from that of a fine
needle to that of a common pin. The green hydra
and the brown hydra, both very small, are common
species, though hydras are often white or colourless.
They should be kept ina large glass dish filled with
water. They may be distinguished by the naked
eye but are not studied satisfactorily without a
magnifying glass or microscope. Place a living specimen attached
to a bit of wood in a watch crystal filled with water, or on a hol-
lowed slip, or on a slip with a bit of weed to support the cover
glass, and examine with hand lens or lowest power of microscope.
Prepared microscopical sections, both transverse and longitudinal,
may be bought _ ts
of dealers in mi- i
croscopic sup-
plies: (One as) ie
shown in Fig. 39. ts...

A HYDRA.

Is the hy- *
dra’s a wy I
round or two- Ygqeepoeaisieintesiateratse siento
ee (Fig. cs 34 ele (a me
35.) What is a

its general shape? Does one individual keep the same
shape? (Fig. 34.) How does the length of the thread-

22

POLYPS (CUPLIKE ANIMALS) 23

like tentacles compare with the length of the hydra’s body ?
About how many tentacles are on a hydra’s body? Do all
have the same number of tentacles? Are the tentacles
knotty or smooth? (Fig. 35.) The hydra is usually ex-
tended and slender ; sometimes it is contracted and rounded.
In which of these conditions is the base (the foot) larger
around than the rest of the body? (Fig. 34.) Smaller?
How many openings into the
body are visible? Is there a
depression or an eminence at
the base of the tentacles? For
what is the opening on top of
the body probably used ? Why
are the tentacles placed at the
top of the hydra’s body? Does
the mouth have the most con-
venient location possible ?
The conical projection bear-
ing the mouth is called hypo-
stome (Fig. 34). The mouth )
opens into the digestive cavity. Ei. aa (uch
Is this the same as the general
body cavity, or does the stomach have a wall distinct from
the body cavity? How far down does the body cavity
extend? Does it extend up into the tentacles? (Fig. 39.)

If a zentacle ts touched, what happens? Is the body ever bent?
Which is more sensitive, the columnar body or the tentacles? In
searching for hydras would you be more likely to find the ten-
tacles extended or drawn in? Is the hypostome ever extended
or drawn in? (Fig. 34.)

Locomotion. — The round surface, or disk, by which the
hydra is attached, is called its foot. Can you move on
one foot without hopping? The hydra moves by alter-

24 BEGINNERS” ZOOLOGY

nately elongating and rounding the foot. Can you dis.
cover other ways by which it moves? Does the hydra
always stand upon its foot ?

Lasso Cells. — Upon the tentacles (Fig. 35) are numer-
ous cells provided each with a thread-like process (Fig. 36)
which lies coiled within the
cell, but which may be
thrown out upon a water
flea, or other minute animal
that comes in reach. The
touch of the lasso paralyzes
the prey (Fig: 37): “These
cells are variously called
lasso cells, nettling cells, or
thread cells. The thread is
hollow and is pushed out by the pressure of liquid within.
When the pressure is withdrawn the thread goes back as
the finger of a glove may be turned back into the glove by
turning the finger outside in.

FIG. 36. — NETTLING CELL.
II. discharged, and I. not discharged.

When a minute animal, or
other particle of food comes in
contact with a tentacle, how
does the tentacle get the food
to the mouth? By bending
and bringing the end to the
mouth, or by shortening and
changing its form, or in both
ways? (Fig. 34, C.) Do the
neighbouring tentaclesseem to
bend over to assist a tentacle in
securing prey? (Fig. 34, C)

Digestion. — The food parti-

inet FIG. 37. — HYDRA capturing a
cles break up before remaining water flea.

POLYPS (CUPLIKE ANIMALS) 25

long in the stomach, and the nutritive part is absorbed
by the lining cells, or endoderm (Fig. 39). The indiges-
tible remnants go out through the mouth. The hydra is
not provided with a special vent. Why could the vent not
be situated at the end opposite the mouth ?

Circulation and Respiration. — Does water have free
access to the body cavity? Does the hydra have few or
nearly all of its cells exposed to the water in which it
lives? From its structure, decide whether it can breathe
like a sponge or whether

special respiratory cells are
necessary to supply it with
oxygen and give off carbon
dioxide. Blood vessels are
unnecessary for transfer-
ring oxygen and food from
cell to cell. \
Reproduction. a7 Bo you FIG. 38.— Hypras on the under sur-
see any swellings upon the face of pondweed.
side of the hydra? (Fig. 34, A.) If the swelling is near
the tentacles, it is a spermary, if near the base, it is an
ovary. A sperm coalesces with or fertilizes the ovum after
the ovum is exposed by the breaking of the ovary wall.
Sometimes the sperm from one hydra unites with the ovum
of another hydra. This is called cvossfertilization. The
same term is applied to the process in plants when the
male element, developed in the pollen of the flower, unites
with the female element of the ovule of the flower on
another plant. The hydra, like most plants and some other
animals, is hermaphrodite, that is to say, both sperms and
ova are produced by one individual. In the autumn, eggs
are produced with hard shells to withstand the cold until
spring. Sexual reproduction takes place when food is

26 BEGINNERS’ ZOOLOGY

scarce. Asexual generation (by budding) is common with
the hydra when food supply is abundant. After the bud
grows to a cer-
tain size, the
outer layer of
cells at the base
of the bud con-
stricts and the
young hydra is
detached.
Compare the
ECTODERM CELLS sponge oe fe

INTERSTITAL Do hydra in the fol-
MUSCLE LAYER

lowing respects:
MESOGLEA
ENDODERM CELL —many celled,
OVARY. a hee or one celled;
ovum tA‘e®

enteric cavity# Obtaining food ;
breathing; tubes
and __ cavities ;
openings; re-
production ; loco-

FIG. 39. — Longitudinal section of hydra (microscopic motion. Which
and diagrammatic).

VACUOLE

ranks higher
among the metazoa? The metazoa, or many celled ani-
mals, include all animals except which branch ?

Figure 39 is a microscopic view of a vertical section of a hydra to
show the structure of the body wall. There is an outer layer called the
ectoderm, and an inner layer called the exdoderm. There is also a thin
supporting layer (black in the figure) called the szesoglea. The mesoglea
is the thinnest layer. Are the cells larger in the endoderm or the ectoderm?
Do both layers of cells assist in forming the reproductive bud? The ecto-
derm cells end on the inside in contractile tails which form a thin line and
have the effect of muscle fibres. They serve the hydra for its remarkable
changes of shape. When the hydra is cut in pieces, each piece makes a
complete hydra, provided it contains both endoderm and ectoderm.

POLYPS (CUPLIKE ANIMALS) 27

In what ways does the hydra show “ division of labour’’? Answer
this by explaining the classes of cells specialized to serve a different
purpose. Which cells of the hydra are least specialized? In what par-
ticulars is the plan of the hydra different from that of a simple sponge?
An ingenious naturalist living more than a century ago, asserted that it
made no difference to the hydra whether the ectoderm or the endoderm
layer were outside or inside, —that it could digest equally well with
either layer. He allowed a hydra to swallow a worm attached to a
thread, and then by gently pulling in the thread, turned the hydra inside
out. More recently a Japanese naturalist showed that the hydra could
easily be turned inside out, but he also found that when left to itself
it soon reversed matters and returned to its natural condition, that
the cells are really specialized and each layer can do its own work and
no other.

Habits. — The hydra’s whole body is a hollow bag, the
cavity extending even into the tentacles. The tentacles
may increase in number as the hydra grows but seldom
exceed eight. The hydra has more active motion than
locomotion. It seldom moves from its place, but its ten-
tacles are constantly bending, straightening, contracting,
and expanding. The body is also usually in motion, bend-
ing from one side to another. When the tentacles ap-
proach the mouth with captured prey, the mouth (invisible
without a hand lens) opens widely, showing five lobes or
lips, and the booty is soon tucked within. A hydra can
swallow an animal larger in diameter than itself.

The endoderm cells have ameboid motion, that is, they
extend pseudopods. They also resemble amcebas in the
power of zztra-cellular digestion ; that is, they absorb the
harder particles of food and digest them afterwards, re-
jecting the indigestible portions. Some of these cells have
flagella (see Fig. 39) which keep the fluid of the cavity
in constant motion.

Sometimes the hydra moves after the manner of a small
caterpillar called a “measuring worm,” that is, it takes
hold first by the foot, then by the tentacles, looping its

28 BEGINNERS’ ZOOLOGY

LP s

defensive (S) hydranths

cells, but the hydra has not a nervous sys¢em.

FIG. 40.— HyDRorp CoLony, with
nutritive (P) reproductive (47) and

body at each step. Sometimes
the body goes end over end in
slow somersaults.

The length of the extended
hydra may reach one half
inch. When touched, both
tentacles and body contract
until it looks to the unaided
eye like a round speck of
jelly. This shows sexszbzlity,
and a few small star-shaped
cells are believed to be xerve
Hydras

show their liking for light by moving to the side of
the vessel or aquarium whence the light comes.

The Branch Polyps
¢sometimes called Calen-
terata). ~ The hydra is
the chief fresh-water rep-
resentative of this great
of the animal
This branch
is characterized by its

branch
kingdom.
members having only
one opening to the body.
The polyps also include
the salt water animals
called hydroids, jelly-
fishes, and coral polyps.

Hydroids. — Figure 4o
shows a Aydroid, or

hydra-like
growths, one of which

group. of

: ake,

FIG. 41.—‘‘ PORTUGUESE MAN-O’-WAR”
(compare with Fig. 40). A floating
hydroid colony with long, stinging (and
sensory) streamers. Troublesome to
bathers in Gulf of Mexico, Notice
balloon-like float.

POLYPS (CUPLIKE ANIMALS) 29

eats and digests for the group, another defends by nettling
cells, another produces eggs. Each hydra-like part of a
hydroid is called a hydvanth. Sometimes the buds on the
hydra remain attached so long that a bud forms upon the
first bud. Thus three generations are represented in one
organism. Such growths show us that it is not always
easyi. eto: 5.tell
what consti-
tutes an indi-

aS /

vidual animal.
Hydrotds
may be con-

i
a
¥
Ls
¥
‘
\.
vi
¥
4

ceived Zo have
been developed
by the failure

of budding hy-

FIG. 42.— The formation of many free swimming jelly-
dras to sepa- fishes from one fixed hydra-like form. The saucer-like
rate from the parts (2) turn over after they separate and become like
Fig. 43 or 44. Letters show sequence of diagrams.

ann

parent, and by
the gradual formation of the habit of living together and
assisting one another. When each hydranth of the hydroid
devoted itself to a special function of digestion, defence, or
reproduction, this group lived longer and prospered; more
eggs were formed, and the habits of the group were trans-
mitted to a more numerous progeny than were the habits
of a group where members worked more independently of
one another.

As the sponge is a simple example of the devotion
of special cells to special purposes, the hydroid is a
primitive and simple example of the occurrence of organs,
that is of special parts of the body set aside for a special
work.

30 BEGINNERS’ ZOOLOGY

How many mature hydranths are seen in the hydroid
shown in Fig. go? Why are the defensive hydranths
on the outside of the
colony? Which hy-
dranths have no tenta-
cles?) Why not?

Jellyfish. — Alterna-
tion of Generations. —
Medusa. — With some
species of hydroids, a
very curious thing hap-
pens. — The hydranth
that 1s to produce the
eggs falls off and be-
comes independent of
the colony. More sur-
prising still, its appear-
ance changes entirely and instead of being hydra-like, it
becomes the large and complex creature called jellyfish
(Fig. 43). But
the egg of the
jellyfish — pro-
duces a small
hydra-like ant-
mal which gives
rise by budding
to a hydroid,
and the cycle is
complete.

The bud (or
reproductive
hydranth) of
the hydroid Fic. 44. —A JELLYFISH (medusa).

FIG. 43. —A JELLYFISH.

POLYPS (CUPLIKE ANIMALS) 31

does not produce a hydroid, but a jellyfish; the egg of the
jellyfish does not produce a jellyfish, but a hydroid. This is
called by zoologists, alternation of generations. A complete
individual is the life from the germination of one egg to
the production of another. So that an “individual” con-
sists of a hydroid colony fixed in one place together with
all the jellyfish produced from its buds, which may
now be floating miles away from it in the ocean. Bathers
in the surf are sometimes touched and stung by the long,
streamer-like tentacles of the jellyfish. These, like the
tentacles of the hydra,- have
nettling cells (Fig. 41).

The umbrella-shaped free
swimming jellyfish is called a
medusa (Fig. 44). |

Coral Polyps. — Some of the
salt water relatives of the hydra
produce buds which remain
attached to the parent without,

FIG. 45.— CORAL POLYPs (tenta-
however, becoming different cles, a multiple of six). Notice

from the parent in any way. eae
The coral polyps and corallines are examples of colonies of
this kind, possessing a common stalk which is formed as
the process of multiplication goes on. In the case of coral
polyps, the separate animals and the flesh connecting them
secrete within themselves a hard, “my, supporting structure
known as coral. In some species, the coral, or stony part,
is so developed that the polyp seems to be inserted in the
coral, into which it withdraws itself for partial protection
(Fig. 45).

The corallines secrete a smooth stalk which affords
no protection, but they also secrete a coating or sheath
which incloses both themselves and the stalk. The

32 BEGINNERS’ ZOOLOGY

coating has apertures through which the polyps pro-
trude in order to feed when no danger is near (Fig. 46).

FIG. 46.— RED CORAL-
LINE with crust and
polyps (ezght tentacles). FIG, 47. — SEA FAN (a coralline).

The red “corals” used for jewelry are bits of stalks of cor-
allines. The corallines (Figs. 47, 48) are not so abundant
nor so important
as the coral polyps
(Figs. 45, 49).
Colonies of coral
polyps grow in
countless numbers
in the tropical seas.
The coral formed
by successive colo-
nies of polyps accu-
mulates and builds

up many islands

Fic. 48. — ORGAN PIPE ‘‘ Coral" (a coralline).

and important addi-

’

tions to continents. The Florida “keys,” or islands, and

the southern part of the mainland of Florida were so

formed.

POLYPS (CUPLIKE ANIMALS)

The Sea Anemone, like the coral
polyp, lives in the sea, but like
the fresh-water hydra, it deposits
no limy support for its body. The
anemone is much larger than the

~

FIG. 50.—SEA ANEMONE.

hydra and
most coral
polyps,
many spe-
eres." at:
taining a
height of
several
inches. It
does not
form colo-

nies. When its arms are drawn in,

FIG. 49. — UPRIGHT CUT
through coral polyp X 4.

ms, mouth; wz, gullet; Zs,
és, fleshy partitions (mesen-
teries) extending from outer
body wall to gullet (to in-
crease absorbing surface) ;
s, 5, shorter partitions; 725,
Jeb, stony support (of lime,
called coral); 7, tentacles.

it looks like a large knob of shiny but opaque jelly. Polyps
used to be called zoophytes (plant-animals), because of
their flower-like appearance (Figs. 50, 51).

Db FIG. 51. — SEA ANEMONES.

CHAPTER .V
ECHINODERMS (SPINY ANIMALS)

THE STARFISH

SUGGESTIONS. Since the echinoderms are aberrant though inter-
esting forms not in the regular line of development of animals, this
chapter may be
omitted if it
is desired to

shorten the
course. — The
common - star-
fish occurs

along the At-

lantic coast. It

is captured by

Ltd hone wading along

FIG. 52. — Starfish on a rocky shore, the shore when

the tide is out.

It is killed by immersion in warm, fresh water. Specimens are usually

preserved in 4 per cent formalin. Dried starfish and sea urchins are also

useful. A living starfish kept

in a pail of salt water will be
instructive.

i

External Features. — 5~~
Starfish are usually brown
or yellow. Why? (See
Fig.52.) Has it ahead or
a tail? Rightand left sides?
What is the shape of the
disk, or part which bears
the five arms or vays? (Fig. 53.) Does the body as a whole
have symmetry on two sides of a line (bilateral symmetry), or
around a point (radial symmetry)? Do the separate rays have

34

FIG. 53.— PLAN of starfish; III, madreporite.

ECHINODERMS (SPINY ANIMALS) 35

bilateral symmetry? The ske/e¢on consists of limy plates embedded
in the tough skin (Fig. 54). Is the sé7z rough or smooth? Hard
or soft? Are the projections (or spines)
in the skin long or short? The skin is
hardened by the
limy plates, ex-
cept around the is
mouth, which is_ Fic. 54.—LIMy PLATES
atthe. centre sof in portion of a ray.
the lower side and surrounded by a mem-
brane. Which is rougher, the mouth side,
(era/ side) or the opposite (adora/ side) ?
Which side is more nearly flat? The
vent is at or near the centre of the
disk on the aboral surface. It is usually
very small and sometimes absent. Why a vent is not of much
use will be understood after learning how the starfish takes food.

An organ peculiar to animals of this
branch, and called the madreporic plate,
or madreporite, is found on the aboral
surface between the bases of two rays
(Fig. 55). It is wartlike, and usually
white or red. This plate is a szeve ; the PAp
small openings keep out sand but allow
water to filter through.

Movements: the Water-tube System.
— The water, which is filtered through
the perforated madreporite, is needed
to supply a system of canals (Fig. 56).
The madreporite opens into a canal
called the stone cana/, the wall of which
is hardened by the same kind of mate- yg, 56, — WaTER tube
rial as that found in the skin. ‘The stone SysTEM of starfish.
canal leads to the 77mg canal which sur- Et fe ee
rounds the mouth (Fig. 56). The ring
canal sends radial canals into each ray to supply the double row
of tube feet found in the groove at the lower side of each ray
(Fig. 57). Because of their arrangement in rows, the feet are

FIG. 55. —Starfish (showing
MADREPORITE).

4

36 BEGINNERS’ ZOOLOGY

also called ambulacral feet (Latin agndulacra, “ forest walks iy
There is a water holder (amfud/a), or muscular water bulb at the
base of each
tube foot (Fig.
58). These con-
tract and force
the water into
the tube feet and
extend them.
The cuplike
ends| of the

~ wan Aba drten ore > Ty

}
t

wba reagan Py tubes cling to
Ad hy Ad S22 SES SEATIN ( :
oY ae iMac) st the ground by
$F SON SY suction. The
BES feet contain
= SS .
JENS delicate muscles
RW ;
A by which they

x contract and

shorten. Thus
the animal pulls
itself slowly
along, hundreds of feet acting together. The tube feet, for their
own protection, may contract and retire into the groove, the
water which extended them being sent back into the ampulla.
This system of water
vessels (or water-
vascular system) of
the echinodermata
is characteristic of
thems" (7.2. “11s \" not
found elsewhere in
the animal kingdom.

FIG. 57. —Starfish, from below; tube feet extended.

FIG. 58.—SECTION OF ONE RAY and central portion

h of starfish.
The grooves and the Ji» Fo» Jy tube feet more or less extended; az, eye spot;
plates on each side k, gills; da, stomach; », madreporite; s¢, stone canal;

?f, ampulla; e7, ovary.

of them occupy the
ambulacral areas. The rows of spines on each side of the grooves
are freely movable. (What advantage?) ‘The spines on the aboral
surface are not freely movable.

ECHINODERMS (SPINY ANIMALS) 37

Respiration. — The system of water vessels serves the additional
purpose of bringing water containing oxygen into contact with
various parts of the body, and the starfish was formerly thought
to have no special respiratory organs. However, there are holes in
the aboral wall through which the folds of the delicate lining mem-
brane protrude. These are now supposed to be gid/s (2, Fig. 58).

The nervous system is so close to the aboral surface that much
of it is visible without dissection. Its chief parts are a nerve ring
around the mouth, which sends off a dranch along each ray.
These branches may be seen by separating the
rows of tube feet. ‘They end in a pigmented
cell at the end of each ray-called the eye-sfot.

The food of starfish consists of such animals
as crabs, snails, and oysters. When the prey
is too large to be taken into the mouth, the
starfish dZurns its stomach inside out over
the prey (Fig.59). After the shells separate,
the stomach is applied to the soft digestible
parts. After the animal is eaten, the stomach — FIG.59. — Starfish eat.
is retracted. This odd way of eating is very ees eae
economical to its digestive powers, for ondy
that part of the food which can be digested and absorbed ts taken
into the body. Only the lower part of the stomach is wide and
extensible. The upper portion (next to the aboral surface) is
not so wide. This portion receives the secretion from five
pairs of digestive glands, a pair of which is situated in each ray.
Jaws and teeth are absent. (Why?) ‘The vent is sometimes
wanting. Why?

Reproduction. — There is a pair of ovaries at the base of each
ray of the female starfish (Fig. 58). The spermaries of the male
have the same position and form as the ovaries, but they are
of a lighter colour, usually white.!

Regeneration after Mutilation. —If a starfish loses one or more
rays, they are replaced by growth. Only a very ignorant oyster-
man, angry at the depredations of starfish upon his oyster beds,

6, stomach everted.

1The sperm cells and egg cells are poured out into the water by the adults,
and the sperm cell, which, like nearly all sperm cells, has a vibratory, tail
like flagellum to propel it, reaches and fertilizes the egg cell.

38 BEGINNERS’ ZOOLOGY

would chop starfish to pieces, as this only serves to multiply them.
This power simulates multiplication by division in the simplest
animals.

Steps in Advance of Lower Branches. — The starfish and other
echinodermata have a more developed nervous system, sensory
organs, and digestion, than forms previously studied ; most dis-
tinctive of all, they have a body
cavity distinct from the food
cavity. The digestive glands,
reproductive glands, and the
fluid which serves imperfectly
for blood, are in the body
cavity. There is no heart or
blood vessels. The motions
of the stomach and the bend-
ing of the rays give motion to
this fluid in the body cavity.
It cannot be called blood,
but it contains white blood
=; corpuscles.
Fic. 60, — Young starfish crawling upon The starfish when first

their mother. (Challenger Reports.) hatched is an actively swim-
ming bilateral animal, but it soon becomes starlike (Fig. 60). The
limy plates of the starfish belong neither to the outer nor to the inner
layer (endoderm and ectoderm) of the body wall, but to a third
or middle layer (mesoderm) ; for echinoderms, like the polyps,
belong to the three-layered animals. In this its skeleton differs
from the shell of a crawfish, which is formed by the hardening
of the skin itself.

Protective Coloration. — Many starfish are brown or yellow. This
makes them inconspicuous on the brown rocks or yellow sand.
Brightly coloured species are usually chosen for aquaria.

THE SEA URCHIN
External Features. — What is the shafe of the body? What
kind of symmetry has it? Do you find the oral (or mouth) sur-
face? The aboral surface? Where is the body flattened? What
is the shape of the spines? What is their use? Howare the tube

ECHINODERMS (SPINY ANIMALS) 39

feet arranged? Where do the rows begin and end? Would you
think that a sea urchin placed upside down in water, could right it-
self less or more readily than a
star-fish? What advantage in
turning would each have that the

other would not have? The
name sea urchin has no refer-
ence to a mischievous boy, but
means sea hedgehog (French
oursin, hedgehog), the name
being suggested by its spines.

Comparison of Starfish and
Sea Urchin. — The water sys-
tem of the sea urchin, consist- : =
ing of madreporite, tubes, and FIG. 61.—A SEA URCHIN crawling up
water bulbs, or ampulle, is the Blass front wall of an aquarium
aad (showing mouth spines and tube feet),
similar to that of the starfish.
The tube feet and jocomotion are alike. There is no need for
well-developed respiratory organs in either animal, as the whole
body, inside and out, is bathed in water. The method of repro-
duction is the same.

The starfish eats soft animal food. The food of the sea
urchin is mainly vegetable, and it needs teeth (Fig. 62, 63 ) ;

= r —e =p

FIG. 62. — A SEA URCHIN

with spines removed, - FIG. 63. —SECTION OF SEA URCHIN
the limy plates showing with soft parts removed, showing the
the knobs on which the jaws which bear the teeth protruding
spines grew. in Fig. 62.

its food tube is longer than that of a starfish, just as the food tube
of a sheep, whose food digests slowly, is much longer than that of
a dog.

4o BEGINNERS” ZOOLOGY

The largest species of sea urchins are almost as big as a
child’s head, but such size is unusual. The spines are mounted
on knobs, and the joint resembles a
ball-and-socket joint, and allows a wide
range of movement. Some sea urchins
live on sandy shores, other species live
upon the rocks. ‘The sand dollars are
of a lighter colour. (Why)? They are usu-
ally flatter and have lighter, thinner
walls than the other species. The five-
holed sand cake or sand dollar has its
weight still further diminished by the

FIG. 64.— THE SEA OT- E . i
TER, an urchin with holes, which also allow it to rise more

mouth (0) and vent (4) easily through the water.

pelea uae ose on ody. Both starfish and sea urchin rest on

the flattened lower surface of the body,
while the tube feet are stretching for-
ward for another step.

OTHER ECHINODERMS

The sea cucumbers, or holothurians, re-
semble the sea urchin in many respects,

FIG. 65.—SEA CUCUMBERS.

but their bodies are elon-
gated, and the limy plates
are absent or very mi-
nute. The mouth is sur-
rounded by tentacles (Fig,
65).

The brittle stars resem-
ble the starfish in form,
but their rays are very
slender, more distinct
from the disk, and the tube feet are on the edges of the rays, not
under them (Fig. 66).

Az fs
linn
SH geld

sigan tekst Cet
a wr: re

FIG. 66.—A BRITTLE STAR.

FIG. 67. —
CRINOID,
arms closed.

ECHINODERMS (SPINY ANIMALS) 41

The crinoids are the most ancient of the echino«
Their fossils are very

derms. (Figs. 67, 68.)
abundant in the rocks. They
inhabited the geological seas,
and it is believed that some of
the other echinoderms de-
scended from them. A few
now inhabit the deep seas.
Some species are fixed by
stems when young, and later
break away and become free-
swimming, others remain
fixed throughout life.

FIG. 68.— Disk OF CRI-
NOID from above, show-
ing mouth in centre
and vent near it, at
right (arms removed).

The four classes of the branch echinoderms are
Starfish (aséeroids), Sea urchins (echinotds), Sea
cucumbers (Aolothurians), and Sea lilies (¢crinozds).

Comparative Review

Make a table like this as large as the page of the

notebook will allow, and fill in without guessing.

CorAL

STARFISH

Amaba

SPONGE

Hypra

PoLyp

Is body round, two-
sided, or irregular

What organs of sense

Openings into body

Hard or supporting
parts of body

How food is taken

How move

How breathe

CHAPTER VI
WORMS

SuccEsTIons : — Earthworms may be found in the daytime after
a heavy rain, or by digging or turning over planks, logs, etc., in
damp places. They may be found on the surface at night by
searching with a lantern. Live specimens may be kept in the
laboratory in a box packed with damp (not wet) loam and dead
leaves. They may be fed on bits of fat meat, cabbage, onion,
etc., dropped on the surface. When studying live worms, they
should be allowed to crawl on damp paper or wood. An earth-
worm placed in a glass tube with rich, damp soil, may be watched
from day to day.

External Features. — Is the body dz/ateval? Is there a
dorsal and aventra! surface? Can you show this by a test
with live worm? Do you know of an animal with dorsal
and ventral surface, but not
bilateral ?

Can you make out a head ?

see: Aheadend? Aneck? Touch
Beg eer aoe the head and test whether it
can be made to crawl backwards. Which end is’ more
tapering? Is the mouth at the tip of the head end or on

the upper or lower surface? How is the vev¢ situated?
Its shape? As the worm lies on a horizontal surface, is
the body anywhere flattened? Are there any very distinct
divisions in the body? Do you see any eyes ?

Experiment to find whether the worm is sensitive (1) to souch,

(2) to Zight, (3) to strong odours, (4) to irritating liquids. Does it
show a sense of fas#? ‘The experiments should show whether

42

WORMS 43

it avoids or seeks a bright light, as of a window; also whether any
parts of the body are especially sensitive to touch, or all equally
sensitive. What effect when a bright light is brought suddenly near
it at night ?

Is ved blood visible through the skin? Can you notice
any pulsations in a vessel along the back? Do all earth-
worms have the same number of adzvzszons or rings? Com-
pare the size of the rings or segments. Can it crawl faster
on glass or on paper?

A magnifying glass will show on most species tiny bristle-
like projections called sete. How are the sete arranged?
(d, Fig. 70.) How many on
one ring of the worm? How
do they point? Does the worm
feel smoother when it is pulled
forward or backward between

FIG. 70.— MOUTH AND SET,

the fingers? Why? Are sete on the lower sur-
face? Upper surface? The sides? What is the
use of the setee? Are they useful below ground ?
Does the worm move at a uniform rate? What
change in form occurs as the front part of the
body is pushed forward? As the hinder part is
pulled onward? How far does it go at each
movement? At certain seasons a broad band,
or ring, appears, covering several segments and
making them seem enlarged (Fig. 71). This is
y the clitellum, or reproductive girdle. Is this girdle

EarTH- nearer the mouth or the tail?

WORM, .
mouthend Draw the exterior of an earthworm.

NG. Dorsal and Ventral Surfaces. — The earthworm
always crawls with the same surface to the ground; this
is called the ventral surface, the opposite surface is the
dorsal surface. This is the first animal studied to which

BEGINNERS’ ZOOLOGY

these terms are applicable. What are the
ventral and dorsal surfaces of a fish, a frog,
a bird, a horse, a man?

The name “ worm” is often carelessly applied
to various crawling things in general. It is prop-
erly applied, however, only to segmented animals
without jointed appendages.
Although a caterpillar crawls,
it is not a worm for several
reasons. It has six jointed
legs, and it is not a developed
animal, but only an early stage
in the life of a moth or a but-
terfly. A “ grubworm”’ also
has jointed legs (Fig. 167).
It does not remain a grub, but
in the adult stage is a beetle.

| A worm never develops into
FIG. 72,— FOOD another animal in the latter
TUBE of earth- : J i
worm. (Top Part of its life; its sete are
view.) not jointed.

The Food Tube. — The earthworm has
no teeth, and the food tube, as might be
7 inferred from the form of the Fic. 73.—Foop

is sl ; TUBE AND
e Ss
body, is simple and straight. It Begala
parts, recognizable because of EE A a
slight differences in size and worm showing
a the _ ring-like
structure, are named the pharynx hearts. (side
view.)

(muscular), gullet, crop, gizzard
(muscular), and stomach-intestine. The last ex-
tends through three fourths of the length of the
body (Fig. 72). The functions of the parts of
— the food tube are indicated by their names.
Circulation. —There is a Jarge dorsal blood
vessel above the food tube (Fig. 73). From the

WORMS 45

front portion of this tube arise several large tubular rings
or “hearts” which are contractile and serve to keep the
blood circulating. They lead to a ventral vessel below the
food tube (Fig. 74). The blood is red, but the colouring
matter is in the liquid, not in the blood cells.

Nervous System.— Between the ventral blood vessels
is a nerve cord composed of two strands (see Fig. 75).
There is a slight swelling, or gang/ion, on each strand, in
each segment (Fig. 75). The strands sepa-
rate near the front end of the worm, and a
branch goes up each side of the gullet and
enters the two pear-shaped cerebral ganglia,
or “brain”’ (Fig. 75).

Food. — The earthworm eats earth contain-
ing organic matter, the inorganic part passing
through the vent in the form of circular casts;
these are found in the morning at the top of

FIG. 75.—
GANGLIA
The earthworm has no teeth. It excretes NEAR MoutH

the earthworm’s burrow.
through the mouth an alkaline flutd which ey ee
softens and partly digests the food before it earthworm.
is eaten. When this fluid is poured out upon a green leaf,
the leaf at once turns brown. The starch in the leaf is
also acted upon. The snout aids in pushing the food into
the mouth.

Kidneys. — Since oxidation is occurring in its tissues,
and impurities are forming, there must be some way of
removing intpurities from the tissues. The earthworm
does not possess one-pair organs like the kidneys of
higher animals to serve this purpose, but it has numerous
pairs of small tubular organs called xephridia which serve
the purpose. Each one is simply a tube with several coils.
There is a pair on the floor of each segment. Each neph-

46 BEGINNERS’ ZOOLOGY

ridium has an inner open end within the body cavity, and
its outer end opens by a pore on the surface between the
sete. The nephridia absorb waste
from the liquid in the celom, or body
cavity surrounding the food tube,
and convey it to the outside.
Respiration.— The skin of the
earthworm is moist, and the blood
capillaries approach so near to the
Fic. 76.—Two pairs surface of the body that the oxygen
Pee aaeen is constantly passing in from the air,
and carbon dioxide passing out; hence
it is constantly breathing through all parts of its skin.
It needs no lungs nor special respiratory organs of any
kind.

Reproduction. — When one individual animal produces both
sperm cells and egg cells, it is said to be hermaphrodite. This
is true of the earthworm. ‘The egg cell
is always fertilized, however, not by the
sperm cells of the same worm, but by
sperm cells formed by another worm.
The openings of these ovaries consist of
two pairs of small pores found in most
species on the ventral surface of the
fourteenth segment (see Fig. 77). There
are also two pairs of small vecepfacles
for temporarily holding the forezgn sperm
cells, One pair of the openings from
these receptacles is found (with diffi-
culty) in the wrinkle behind the ninth
segment (Fig. 77), and the other pair
behind the tenth segment. The sferm-
aries are in front of the ovaries (Fig. 77), but the sperm ducts
are longer than the ov/ducts, and open behind them on the fifteenth
segment (Figs. 77, 78). ‘The worms exchange sperm cells, but not

FIG. 77.—Sperm (sf) and
egg glands (es) of worm.

WORMS 47

egg cells. The reproductive girdle, or cUite//um, already spoken of,
forms the case which is to hold the eggs (see Fig. 71). When the
sperm cells have been exchanged, and the ova are ready for fertili-
zation, the worm draws itself backward from the collar-like case or
clitellum so that this slips over the head. As it passes the four-
teenth segment, it collects the ova, and as it passes the ninth and
tenth segments, it collects the sperm cells previously
received from another worm. The elastic, collar-like
clitellum closes at the ends after it has slipped over the
worm’s head, forming a capsule. The ova are fertilized
in this capsule,and some of them hatch into worms in
a few days. These devour the eggs which do not
hatch. The eggs develop into complete but very
small worms before escaping from the capsule.

z

.

Habits. — The earthworm is ommuztvorous. It
will eat bits of meat as well as leaves and
other vegetation. It has also the advantage,
when digging its hole, of cating the earth which

: a
must be excavated. Every one has noticed the
fresh “casts” piled up at the holes in the morn- Ze
ing. As the holes are partly filled by rains, the §!6-78.—

: Side view,
casts are most abundant after rains. The chief showing setz,
enemies of the earthworm are moles and birds. nephridia
’ z : x pores, and
The worms work at night and retire so early in yeproductive
the morning that the very early bird has the openings.
advantage in catching worms. Perhaps the nearest to
an intelligent act the earthworm accomplishes is to con-
ceal the mouth of its hole by plugging it with a pebble or
a bit of leaf. Worms hibernate, going below danger of
frost in winter. In dry weather they burrow several feet

STETEETETT
EP) Td) gleghegh

cm
aise

eee
et

deep.

The muscular coat of the body wall is much thicker than
the skin. It consists of two layers: an outer /ayer of fibres
which run around the body just beneath the skin, and an

48 BEGINNERS’ ZOOLOGY

inner, thicker dayer of fibres which run lengthwise. The
worm crawls by shortening the longitudinal muscles. As
the bristles (se¢@) point backward, they prevent the front
part of the body from slipping back, so the hinder part is
drawn forward. Next, the circular muscles contract, and
the bristles preventing the hind part from slipping back,
the fore portion is pushed forward. Is the worm thicker
when the hinder part is being pulled up or when the fore
part is being thrust forward? Does the earthworm pull or
push itself along, or does it do both? Occasionally it trav-
els backward, e.g. it sometimes goes backward into its hole.
Then the bristles are directed forward.

The right and left halves of the body are counterparts of
each other, hence the earthworm is dc/aterally symmetrical.
The lungs and the gills of animals must always be kept
moist. The worm cannot live long in dry air, for respiration
in the skin ceases when it cannot be kept moist. and the
worm smothers. Long immersion in water is injurious to it,
perhaps because there is far less oxygen in water than in
the air.

Darwin wrote a book called ‘‘ Vegetable Mould and Earth-
worms.” He estimated that there were fifty thousand earth-
worms to the acre on farm land in England, and that they
bring up eighteen tons of soil in an acre each year. As
the acids of the food tube act upon the mineral grains that
pass through it, the earthworm renders gveat aid in form-
ing soil. By burrowing it makes the soil more fovous and
brings up the subsoil.

Although without eyes, the worm is sensitive to light
falling upon its anterior segments. When the light of a
lantern suddenly strikes it at night, it crawls quickly to its
burrow. Its sense of touch is so keen that it can detect a
light puff of breath. Which of the foods kept in a box of

WORMS . 49

damp earth disappeared first? What is indicated as toa
sense of taste ?

Why is the bilateral type of structure better adapted for
development and higher organization than the radiate type
of the starfish? The earthworm’s body is a
double tube; the hydra’s body is a single
tube; which plan is more advantageous, and
why ? Would any other colour do just as well
for an earthworm? Why, or why not?

The sandworm (Nereis) lives in the sand of the
seashore, and swims in the sea at night (Fig. 79).
It is more advanced in structure than the earth-
worm, as it has a distinct head (Fig. 80), eyes, two
teeth, two lips, and several pairs of antennz, and
two rows of muscular projections which serve as
feet. It is much used by fishermen for bait. If
more easily obtained, it may be studied instead of
the earthworm.

FIG. 79. —SAND
WORM x 3

There are four classes in the branch Vermes: (Nereis).
I) the worms, including sandworms and leeches; 2) the

roundworms, including trichina, hairworms,
and vinegar eels; 3) flatworms, including
tapeworm and liver fluke; 4) votzfers, which
are microscopic aquatic forms.

The tapeworm is a flatworm which has lost
most of its organs on account of its parasitic
life. Its egg is picked up by an herbivorous
animal when grazing. The embryo under-

FIG. 80. — HEAD ; :
oF Sanpworm goes only partial development in the body

ayaa of the herbivorous animal, ¢.g. an ox. The
next stage will not develop until the beef is eaten by a
carnivorous animal, to whose food canal it attaches itself
and soon develops a long chain of segments called a
“tape.” Each segment absorbs fluid food through its

50 BEGINNERS’ ZOOLOGY

body wall. As the segments at the older end mature,
each becomes full of eggs, and the segments become
detached and pass out of the canal, to be dropped and
perhaps picked tp by an herbivorous animal and the
life cycle is repeated.

The trichina is more dangerous to human life than is the
tapeworm. It gets into the food canal in uncooked pork
(bologna sausage, for example), multiplies there, migrates
into the muscles, causing great pain, and encysts there,
remaining until the death of the host. It is believed to
get into the bodies of hogs again when they eat rats, which
in turn have obtained the cysts from carcasses.

Summary of the Biological Process. —- An earthworm is
a living machine which does work (digging and crawling;
seizing, swallowing, and digesting food; pumping blood:
growing and reproducing). To do the work it must have
a continual sapply of energy. The energy for its work is
set free by the protoplasm (in its microscopic cells) under-
going a destructive chemical change (orzdation). The
waste products from the breaking down of the protoplasm
must be continually removed (excretion). The broken-
down protoplasm must be continually replaced if life is to
continue (the income must exceed the outgo if the animal
is still growing). The microscopic cells construct more
protoplasm out of food and oxygen (asszmzlation) supplied
them by the processes of nutrition (eating, digesting,
breathing, circulating). This protoplasm in turn oxidizes
and releases more energy to do work, and thus the cycle
of life proceeds.

CHAPTER VII

CRUSTACEANS

CRAWFISH

SUGGESTIONS.—In regions where Crayfish are not found, alive
crab may be used. Locomotion and behaviour may be studied by
providing a tub of water, or better, a large glass jar such as a
broad candy jar. For suggestions on study of internal structure,
see p. 58.

Habitat. - Do you often see crawfish, or crayfish, mov-
ing about, even in water where they are known to be abun-
dant? What does your answer suggest as to the time
when they are probably most active ?

Why do you never see one building its chimney, even
where crayfish holes are abundant? Is the chimney
always of the same colour as the surface soil? Are the
crayfish holes only of use for protection? In what kind
of spots are crayfish always dug; Why? What
becomes of crayfish when the pond or the creek dries up?
How deep are the holes? How large are the lumps of
mud of which the chimney is built? How does it get
them out of the hole? Why is the mud built into a chim-
ney instead of thrown away? (What would happen to a
well with its mouth no higher than the ground?) Why
are crayfish scarce in rocky regions ?

How does the colour of the crayfish compare with its
surroundings? Is its colour suited to live in clear or muddy
water? Define protective colouration.

51

52 BEGINNERS’ ZOOLOGY

Habits.— Does thecrayfish walk better in water or out
of it? Why? Does it use the legs with the large claws
to assist in walking? Do the swimmerets (under the ab-
domen) move fast or slow? (Observe it from below ina
large jar of clear water.) What propels it backward?
Forward? Does the crayfish move at a more uniform
rate when swimming backward or forward? Why? In
which way can it swim more rapidly? Do the big legs
with claws offer more resistance to the water while it is
swimming backward or forward? How does it hold the
-tail after the stroke, while it is darting backward through
the water? Hold a crayfish with its tail submerged and
its head up. Can the tail strike the water with much
force? Allow it to grasp a pencil: can it sustain its own
weight by its grip?

Feeding.—Offer several kinds of food to a crayfish that
has not been alarmed or teased. Does it prefer bread,
meat, or vegetables? How does it get the food to its mouth?
Does it eat rapidly or slowly? Does it tear the food with
the big pincers? Can it gnaw with the small appendages
near the mouth?

Breathing.—Does the crayfish breathe with gills or
lungs? Place a few drops of ink near the base of the hind
legs of a crayfish resting quietly in shallow water. Where
is the ink drawn in? Where does it come out? To ex-
plain the cause and the purpose of this motion, place a cray-
fish in a large glass jar containing water, and see the
vibratory motion of the parts under the front portion of
the body. There is under the shell on each side of the body
a gill paddle, or gill bailer, that moves at the same rate.

Senses.—Crayfish are best caught with a piece of meat
or beef’s liver tied to a string. Do they always lose hold
as soon as they are lifted above the water? What do you

CRUSTACEANS 53

conclude as to the alertness of their senses? Does the cov-
ering of their bodies suggest the possession of a delicate or
a dull sense of touch?

Of what motions are the eyes capable? Touch one of
the eyes. The result? Can a crayfish see in all direc-
tions? To test this, place a crayfish on a table and try
whether you can move to a place where you can see the

FIG. 81. — CRAWFISH
(dorsal surface).

crayfish without seeing its eyes. What are the advantages
and disadvantages of having the eyes on stalks?

Touch the body and the several appendages of the
crayfish. Where does it seem most sensitive to ‘ouch ?
Which can reach farther, the antennz or the big claws?
Why are short feelers needed as well as long ones?

Make a loud and sudden noise without jarring the cray-
fish. Isit affected by sound ?

External Anatomy (Figs. 81, 82, 83, 84).-—Is the body of
the crayfish rounded out (convex) everywhere, or is any
part of its surface either flat or rounded in (concave)?

54 BEGINNERS’ ZOOLOGY

What colour has the crayfish? Is this colour of any use to
the crawfish ?

Make out the two distinct regions or azvzszons of the body
(Fig. 81). The anterior (front) region is called the head-
chest or cephalothorax, and the posterior (rear) region is

called the tail.
Which region is
larger? Why?
Which is flex-
ible? Why?

Is the covering
of the body hard
or soft? What
is the advantage of such a covering? What are its dis-
advantages? How is the covering modified at the joints

Fic. 83. —LATERAL VIEW OF CRAWFISH.

to permit motion ?

Tail. — How many joints, or segments, of the tail? (Figs.
81, 83.) Does the hard covering of each segment slip
under or over the segment behind it when
the tail is straight? Does this lessen
friction while swimming forward?

Is there a pair of szwzmmerets to each
segment of the tail? (Figs. 82, 86.)
Notice that each swimmeret has a main FIG. 84.—
stalk (protopod), an outer branch (exopod), aged a
and an inner branch (endopod) (Fig. 84). oF. CRANE
Are the stalk and the branches each in acaba
one piece or jointed? The middle part of the tail fin is
called the telson. By finding the position of the vent,
decide whether the food tube goes into the telson
(Fig. 82). Should it be called an abdominal segment.
Are the side pieces of the tail fin attached to the telson
or to the sixth segment? Do these side pieces correspond

CRUSTACEANS 55

to swimmerets? Do they likewise have the Y-shaped
structure? (Fig. 86.)

If the swimmerets on the first abdominal segment are
large, the specimen is a male. If they are small, it is a
female. Which sex is shown in Fig. 82?

Fig. 86? EPS:

Carapace.— The covering of the head BG YV-:
chest (cephalothorax) is called the cara- (\W% Mis
paces blast) treeved ges? Vheyev//srare
on the sides of the body and are covered
by the carapace (Fig. 87). The projection

in front is called the vostv7wm, meaning beak.
Does the rostrum project beyond the eyes?
There is a transverse grocve across the cara-
pace which may
be said to divide |~
FIG. 85.—1, mandi-

the head from the bie; 2,3,maxille;
abdomen. Where 4,5, 6, maxillipeds.
does this groove end at the sides?
Legs. — How many legs has the
crayfish? How many are provided

with large claws? Small claws?
Is the outer claw hinged in each
of the large grasping pincers?
The inner claw?

Appendages for Taking Food. —

Fic. 86.—CRayFIsH If possible to watch a living cray-
(ventral surface).

fish eating, notice whether it places
the food directly into the mouth with the large claws. Bend
the large claws under and see if they will reach the mouth.

Attached just in front of the legs the crayfish has three
pairs of finger-like appendages, called foot jaws (maxilli-
peds), with which it passes the food from the large pincers

56 BEGINNERS’ ZOOLOGY

to its mouth (Figs. 85, 86). They are in form and in use
more like fingers than feet. In front of the foot jaws are two
pairs of thin jaws
(maxilla) and in
front of the thin
jaws are a pair of
stout jaws (mandi-
bles) (Fig. 85). Do
the jaws move

sidewise or up
Fic. 87. — Gill cover removed and gills exposed. and down? Which
Eee of the jaws has a
jointed finger (palp) attached to it? Do all the appen-
dages for taking food have both exopod and endopod
branches on a basal stalk or protopod? Which of the
appendages have a scalloped edge? How would you know
from looking at the crayfish that it is not merely a
scavenger? Why are there no pincers on the hind feet ?
Sense Organs. — Find the aztenna, or long feelers (Figs.
82, 90). Are the antennz attached above or below the

eyes? (Fig. 87.) =

FIG. 88. — LENGTHWISE SECTION OF MALE CRAWFISH.

c, heart; Ac, artery to head; Aa, artery to abdomen; Ay, stomach; D, intestine;
L, liver; 7, spermary; Go, opening of sperm duct; G, brain; JV, nerve chain.
Find the pair of antennules, or small feelers. Are their
divisions like or unlike each other? Compare the length
of the antennules and the antennze. Compare the flex-
ibility of the antennz with that of the other appendages.

CRUSTACEANS 57

Observe the position of the eyes (Figs. 81, 88). How long
are the eyestalks? Is the stalk flexible or stiff? Touch the
eye. Where is the joint which enables the stalk to move?
Is the outer covering of the eye hard or soft? A mounted
preparation of the transparent covering (cornea) of the
eye, seen with lower power of microscope, reveals that the
cornea is made up of many divisions, called facets. Each
facet is the front of a very small eye, hundreds of which
make up the whole eye, which is therefore called a com-
pound eye. The elongated openings to the car sacs are
located each on the upper side of the base of a small feeler
just below the eye.

Respiratory System. — The respiratory organs are gills
located on each side of the thorax in a space between the
carapace and the body (Fig. 87). The gills are white, curv-
ed, and feathery. Is the front gill the largest or the smallest?
The gills overlap each other; which is the outermost gill ?
On the second maxilla is a thin, doubly curved plate called
a gill bailer (Fig. 85). The second maxilla is so placed
that the gill bailer comes at the front end of the gill
chamber. The bailer paddles continually, bringing the
water forward out of the gill. The gills are attached
below at the base of the legs. Are the gills thick or thin ?
How far upward do they go? Does the backward motion
in swimming aid or hinder the passage of the water through
the gills? Does a crayfish, when at rest on the bottom
of a stream, have its head up or down stream? Why ?

Openings. — The slitlike vent is on the under side of
the telson (Figs. 82, 88). The mouth is on the under side
of the thorax behind the mandibles. At the base of the
long antennz are the openings from the green glands, two
glands in the head which serve as kidneys (Fig. 89).
The openings of the reproductive organs are on the third

58 BEGINNERS’ ZOOLOGY

pair of legs in the female, and the fifth
pair of legs in the male (Fig. 88). The
eggs are carried on the swimmerets.

Internal Structure. — Succrstions. If
studied by dissection, it will be necessary
\“ to have several crayfish for each pupil, one
| for gaining general knowledge, and others for
studying the systems in detail. Specimens
should have lain in alcohol for several days.

The Food Tube.— Is the stomach in the
head portion of the cephalothorax or in the
thoracic portion? ( Figs. 88, 89). Is the stomach
large or small? What is its general shape?
Does the gullet lead upward or backward?
Is it long or short? (Fig. 88.) The mid tube,
which is the next portion of the food tube, is
smaller than the stomach. On each side of
Fic. 89.— Level length- jt are openings from the bile ducts which

iababtpie ham i ea bring the secretion from the digestive gland,

S35 5 EO s

ee

BEp

WpAZNe
SS

VALS

e
S

Soy

h, heart.

Fipreon eladtt: sometimes called the liver. Does this gland
sh extend the whole length of the thorax? Is
AF dick i it near the floor or the top of the cavity?
ma, stomach. The third and last portion of the food tube

(After Huxley.) is the intestine. It extends from the thorax

to the vent. Is it large
or small? Straight or
curved? The powerful
flexor muscles of the tail
lie in the abdomen below
the intestines. Compare
the size of these muscles
with the extensor muscle
above the intestine (Fig.
go). Why this difference?
Does the food tube ex-
tend into the telson? Lo-

: lic. 90,—SECTION OF CRAYFISH showin,
cate the vent (Fig. go). stomach s, liver /é, and vent a.

CRUSTACEANS

The Circulation. — The blood is a liquid containing whzte cor-
puscles. It lacks red corpuscles and is colourless, ‘The heart is in

the upper part of the thorax. It is sur-
rounded by a large, thin bag, and thus it is
in a chamber (called the Jericardial sinus).
The blood from the pulmonary veins enters
this sinus before it enters the heart. The
origin of this pericardial sinus by the fusing of
veins is shown in Fig.i130. Does one artery,
or doseveral arteries, leave the heart? There
is a larger dorsal artery lying on the intestine
and passing back to the telson; there are
three arteries passing forward close to the
dorsal surface (Figs.89,91). One large artery
(the sternal) passes directly downward (Figs.
88, 91), and sends a branch forward and
another backward near the ventral surface.
The openings into the heart from the sinus

have valvular lips which prevent a backward _ Fic. 91.— Showing heart
flow of blood into the sinus. Hence, when and main blood vessels.

FIG. 92.

the heart contracts, the blood is sent out into the sev-
eral arteries. The arteries take a supply of fresh blood
to the eyes, stomach, muscles, liver, and the various
organs. After it has given oxygen to the several organs
and taken up carbon dioxide, it returns by veins to pass
through the gills on each side, where it gives out the use-
less gas and takes up oxygen from the water. [tis then
led upward by veins into the pericardial sinus again.
The central nervous system consists of a double
chain of ganglia (Fig. 92). This main nerve chain
lies along the ventral surface below the food tube
(Fig. 90), except one pair of ganglia which lie
above the cesophagus or gullet (Fig. 88), and are
called the supra-cesophageal ganglia, or brain.

Crustacea—The crayfish and its kindred are placed in
the class called Crustacea.

60 BEGINNERS’ ZOOLOGY

Decapods. — All crustacea which have ten feet belong
in the order called decap'oda (ten-footed). This order
includes the crabs, lobsters, shrimp,

etc. The crabs and the lobsters are of
considerable importance because of
use as food. Small boys sometimes
catch crayfish, and in some instances

FIG. 93. — CRAB FROM are known to cook and eat them for

Bek amusement,

the only part cooked being the
muscular tail. The crab’s tail is
small and flat and held under the

body (Fig. 93).

FIG. 94.-— HERMIT CRAB,

Since the limy covering to serve using shell of sea snail
the purpose of protection is not fomye OSE:
soft enough to be alive and growing, it is evident that the
crustacea are hampered in their growth by their crusty

FIG. 95. — DEVELOPMENT OF A CRAB,

a, nauplius just after hatching; 4,c,d, zoéa; e,megalops; / adult.

Question: Which stage is most like a crayfish? Compare
with metamorphoses of insects.

covering. Dur-
ing the first
year the cray-
fish sheds its
covering, or
moults three
times, and
once each year
thereafter. It
grows very fast
for a few days
justafter moul-
ting, while the ,
covering is soft
and extensible.
Since it. 1s; at

CRUSTACEANS 61

the mercy of birds, fish, and other enemies while in this
soft and defenceless condition, it stays hidden until the
covering hardens. Hence it cannot eat much, but probably
by the absorption of water the tissues grow; that is, enlarge.
In the intervening periods, when growth is impossible, it
develops; that is, the tissues and organs change in structure
and become stronger. ‘ Soft-shelled crab” isa popular dish,
but there is no species by that name, this being only a crab
just after moulting which has been found by fishermen in
spite of its hiding.

General Questions. —How do crayfish choose their food?
How long can they live out of water? Why do their gills remain
moist out of water longer than a fish? How do they breathe
out of water? Are they courageous or cowardly animals? When
they lose appendages in fighting or moulting these are readily
reproduced, but an organ moults several times in regaining its
size. Have you seen crayfish with one claw smaller than the
Compare the crayfish and crab (Figs. 81, 93, and 95) in the
following particulars: shape, body, eyes, legs, abdomen, habitat,
movement.

KEY TO THE FOUR CLASSES IN BRANCH ARTHROPODS

1. INSECTS . . . 3 body divisions, 6 legs

2. ARACHNIDS.. . 2 body divisions, 8 legs

3. Myriapops . . many body divisions, many legs

4. CRUSTACEANS . gill breathers, skeleton (external) limy

By the aid of the key and of figures 96-105, classify the following
Arthropods: tick, thousand-leg centipede, king crab, piil bug, spider,
scorpion, beetle.

BEGINNERS’ ZOOLOGY

| A BEETLE.

FIG. 96.— PILL
Bue,

FIG. tor. — ONE SEG- FIG. 99, — TICK
MENT OF CENTIPEDE before and after
with one pair of legs. feeding.

Pe
fal)
ition
Alb ;
hoo ‘oc’. FIG. 102.—
f rau 2 ONE SEGMENT
ORT OF THOUSAND
{ is HSN LEGS with two
V4 sch Ry, pairs of legs. LEGS.
(A

%
bid % \
(i
Ot ip
f X
FIG. 100. —
CENTIPEDE. FIG. 104.—A SPIDER. FIG. 105. — KING CRAB.

Illustrated Study. CLASSIFICATION OF ARTHROPODS. Key on p. 61,

CHAPTER VIII
INSECTS

THE GRASSHOPPER

Succestions. — Collect grasshoppers, both young and _ full-
grown, and keep alive in broad bottles or tumblers and feed on
tresh grass or lettuce. When handling a live grasshopper, never
hold it by its legs, as the joints are weak. To keep them for
some time and observe their moults, place sod in the bottom of a
box and cover the box with mosquito netting or wire gauze.

What is the general shape of its body? (Fig. 106.)
Where is the body thickest? Is it bilaterally symmetri-
cal, that is, are the two sides of the
body alike? Is the skeleton, or hard
part of the body, internal or external ?
Is the skeleton as stiff and thick 5 WALLY
as that of a crayfish? What is the Fic. 106.—A GRASS-
length of your specimen ? Its colour? OREERS
Why does it have this coloration? In what ways does the
grasshopper resemble the crayfish? Differ from it?

The Three Regions of the Body.—The body of the grass-
hopper is dividedinto three regions—the head, the thorax,
and the abdomen. Which of these three divisions has no dis_
tinct subdivisions? The body of the grasshopper, like that of
theearthworm, is made of ringlike segments. Are theseg-
ments most distinctin the head,the thorax,or the abdomen ?
Which region is longest? Shortest? Strongest? Why?
Which region bears the chief sense organs? The ap-
pendages for taking food? The locomotory appendages?
Which division of the body is most active in breathing ?

63

Pes:

64 BEGINNERS’ ZOOLOGY

The Abdomen. — About how many segments or rings in
the abdomen? Do all grasshoppers have the same num-
ber of rings? (Answer for different species and different
individuals of the same species.) The first segment and
the last two are incomplete rings. Does the flexibility of
the abdomen reside in the rings orin the joints between the
rings? Is there merely a thin, soft line between the rings,
or is there a fold of the covering? Does one ring slip into
the ring before it or behind it when the abdomen is bent ?

As the grasshopper breathes, does each ring enlarge
and diminish in size? Each ring zs divided into two parts
by folds. Does the upper half-ring
overlap the lower half-ring, or the
reverse? With magnifying glass, find
a small slit, called a spzvacle, or breath-
ing hole, on each side of each ring just
above the side groove (Fig. 106). A
tube leads from each spiracle. While
the air is being taken in, do the two

portions of the rings move farther
Fic, 107.—A GRass- apart? When they are brought
SA yi cu Ste together again, what must be the
effect? In pumping the air, the abdomen may be said to
work like a bellows. Bellows usually have folds to allow
motion. Is the comparison correct?

How many times in a minute does the grasshopper take
in air? If it is made to hop vigorously around the room
and the breathing is again timed, is there any change ?

Find the ears on the front wall of the first abdominal
ving (Fig. 107). They may be seen by slightly pressing
the abdomen so as to widen the chink between it and
the thorax. The ears are merely glistening, transparent
membranes, oval in form. A xerve leads from the inner

INSECTS | 65

surface of each membrane. - State any advantage or dis-
advantage in having the ears located where they are.

Ovipositor. —If the specimen is a female, it has an egg-
placer or ovipositor, consisting of four blunt projections at
the end of the abdomen (Fig. 107). If it is a male,
there are two appendages above the end of the abdomen,
and smaller than the parts of the ovipositor. Females
are larger and more abundant than males. In laying
the eggs, the four blunt points are brought tightly to-
gether and then forced into the
ground and opened (Fig. 108). By ©
repeating this, the grasshopper
makes a pit almost as deep as the
abdomen is long. The eggs are
laid in the bottom of the pit.

Draw a side view of the grass-
hopper.

Thorax. — This, the middle por-
tion of the body, consists of ¢iree
segments or rings (Fig. 107). Is the division between the
rings most apparent above or below? Which two of the
three rings are more closely united ?

The front ring of the thorax is called prothorar. Is it
larger above or below? Does it look more like a collar
or acape? (Fig. 106.) A spiracle is found on the second
ring (mesothorax, or middle thorax) just above the second
pair of legs. There is another in the soft skin between
the prothorax and the mesothorax just under the large
cape or collar. The last ring of the thorax is called the
metathorax (rear thorax).

How many legs are attached to each ring of the tho-

EQ
Fic. 108. — GRASSHOPPER
LAYING Eccs. (Riley.)

rax? Can a grasshopper walk? Run? Climb?
Fly?

Do any of the legs set forward?

Jump?
(See Fig. 106.)

66 BEGINNERS’ ZOOLOGY

Outward? Backward? Can you give reasons for the post
tion of each pair? (Suggestion: What is the use of each
pair?) If an organ is modified so that it is suited to serve
some particular purpose or function, it is said to be specza/-
ized. Are any of the legs specialized so that they serve
for a purpose different from that of the other legs?

The leg of a grasshopper (as of all insects) is said to
have five parts, all the small parts after the first four parts
being counted as one part and called the foot. Are all the
legs similar, that is, do the short and the long joints in all
come in the same order? Numbered in order from the

Fic. 109. — HOW A GRASSHOPPER Fic. 110.— HOW A SPIDER
WALKS. WALKS.

body, which joint of the leg is the largest, — the first, sec-
ond, third, or fourth ? Which joint is the shortest? The
slenderest? Which joint has a number of sharp points or
spines on it? Find by experiment whether these spines
are of use in walking (Fig. 106). Jumping? Climbing?
In what order are the legs used in walking? How many
legs support the body at each step?

All animals that have ears have ways of communicating
by sounds. Why would it be impossible for the grasshop-
per to have a vozce, even if it had vocal cords in its
throat? The male grasshoppers of many species make a
chirping, or stridulation, by rubbing the wing against the
leg. Look on the inner side (why not outer side?) of the

INSECTS 67

largest joint of the hind leg for a row of small spines vist
ble with the aid of a hand lens (Fig. 111). The sound is
produced by the outer wings rubbing against the spines.
Have you noticed whether the sound is
produced while the insect is still or in
motion? Why? The male grasshop-
pers of some species, instead of having
spines, rub the under side of the front
wing on the upper side of the hind wing.

Wings. —To what is the first pair
of wings attached? The second pair? Sane
Why are the wings not attached to the — chirping.
prothorax? Whyarethewingsattached 7»the samemore enlarged.
so near the dorsal line of the body? Why are the second
and third rings of the thorax more solidly joined than the
first and second rings?

Compare the first and second pairs of wings in shape,
size, colour, thickness and use (Fig. 112). How are the
second wings folded so as to go
under the first wings? About
how many folds in each ?

FIG. 111.-—A, ROW OF

z, used in

Draw a hind wing opened out.

Head. © What is the shape of
the head viewed from the front, the
side, and above? Make sketches.
What can you say of the neck? Is
the head movable in all directions ?

FIG. 112, — GRASSHOPPER IN What is the position of the large

preHe. eyes? Like the eyes of the cray-
fish, they are compound, with many facets. But the grass-
hopper has also ¢hree simple eyes, situated one in the middle
of the forehead and one just above each antenna. They
are too small to be seen without a hand lens. How does

68 BEGINNERS’ ZOOLOGY

the grasshopper’s range of vision compare with that of the
crayfish ?

Are the antenne flexible? What is their shape? Posi-
tion? Are they segmented? Touch an antenna, a wing,
a leg, and the abdomen in succession. Which seems to be

fest the most sensitive to touch? The antennz
ff \ are for feeling. In some species of insects
)\ p they also are organs of hearing and smelling.
The mouth parts of a grasshopper should

be compared with the mouth parts of a bee-
‘es’ tle shown in Fig. 113, since they correspond

Fic. 113. closely. If the grasshopper is fed with a
blade of fresh grass, the function of each organ may be
plainly seen. It is almost impossible to understand these
functions by studying a dead specimen, but a fresh speci-
_ men is much better than a dry one.

' The upper lip, or Zadrum, is seen in front. Is it tapering
or expanded? In what direction is it movable? The dark
pointed biting jaws (wandzbles) are next. Are they curved

FIG. 114. —a, FooD TUBE OF BEETLE.
4, gizzard ; d, intestine; c, biliary vessels. See Fig. 127.

or straight? Sharp or blunt pointed ? Notched or smooth?
Do they work up and down, or sideways? The holding jaws
(maxilla), each with two jaw fingers (maxillary palpt), are
behind the chewing jaws. Why? The lower lip (/adzum)
has a pair of lip fingers (/abza/ palpz) upon it. The brown

INSECTS 6g

tongue, usually bathed in saliva, is seen in the lower part of
the mouth. Since the grasshopper has no lips, or any way
of producing suction, it must lap the dew in drinking. Does
it merely break off bits of a grass blade, or does it chew?

The heart, circulation, nervous system, digestive and res-
piratory organs of the grasshopper agree mainly with the
general description of the organs of insects given in the
next section.

Microscopic Objects. — These may be bought ready
mounted, or may be examined fresh. A_ portion of the
covering of the large eye may be cut off and the dark layer
on the inside of the covering scraped off to make it trans-
parent. What is the shape of the facets? Can you make
any estimate of
their number? A
portion of the
transparent hind
wing may be used,
and the “veins”
in it studied. A
thin bit of an abdominal segment containing a spiracle

Fic. 115.—EcGc anp Moutts OF A GRASSHOPPER,

will show the structure of these important organs.
Growth of the Grasshopper. — Some species hibernate in
sheltered places and lay eggs in the spring, but adult species
are scarce at that season. Most species lay the eggs in the
fall; these withstand the cold and hatch out inthe spring.
Those hatched from one set of eggs sometimes stay together
fora few days. They eat voraciously, and as they grow, the
soft skin becomes hardened by the deposit of horny sub-
stance called chitin.This retardsfurthergrowthuntil the in-
sect moults,the skin first splitting above the prothorax. Af-
ter hatching, there are five successive periods of growth. At
which moult do the very short wings first appear? (Fig.115)

70 BEGINNERS’ ZOOLOGY

Atter the last moult the animal is complete, and changes
no more in size for the rest of its life. There has been an
ye attempt among writers to restrict the term
grasshopper to the long-winged, slender
family, and to call the shorter winged,
stouter family locusts, according to old
English usage.

Economic Importance of Grasshoppers. —
Great injury is often done to vegetation by
ain Ae grasshoppers ; however, the millions of tiny
CocKRoACH. —_ but ravenous eaters hatched in early spring
are usually soon thinned out by the birds. The migra-

tory locusts constitute a plague when they appear, and

FIG. 117. — PRAYING MANTIS, or devil’s
horse. FIG. 118. — CRICKET.

they have done so since ancient times. The Rocky Moun-
tain locusts flying eastward have darkened the sky, and
where they settled to the earth
ate almost every green thing.
In 1874-5 they produced almost
a famine in Kansas, Nebraska,

FIG, 119. — MOLE CRICKET.

and other Western states. The young hatched away
from the mountains were not healthy,

‘Fp:

smi elas

and died prematurely, and their devas-
tations came to an end. Of course the
migrations may occur again. Packard
' calculates that the farmers of the
FIG. 120.—FRONT West lost $200,000,000 because of grass-
LEG OF MOLE }
CRICKET, x 3. hopper ravages in 1874-5.

INSECTS 71

The cockroaches (Fig. 116), kindred of the grasshoppers,
are household pests that have migrated almost everywhere
that ships go. The praying mantis (Fig. 117), or -devil’s
horse, also belongs to this order. It is beneficial, since it
destroys noxious insects. Which of its legs are specialized?
The walking stick (Fig. 121) and the cricket (Fig. 118), like
most members of the order, are vegetarian.

Are grasshoppers more common in fields and meadows,
or in wooded places? How many different colours have you
seen on grasshoppers? Which

colours are most common?
Grasshoppers are very scarce

in Europe as they love dry,
warm countries. Why do lo-
custs migrate? Give an in-
stance in ancient times.

How long do most grass-
hoppers live? Does a grass-
hopper spread its wings before
it flies? Does it jump and fly
together ?). Can it; select, the
place for alighting ?

Note To TEACHER. — Ficld work in
Zoology should be systematic. Every trip FIG. 121. — FOUR WALKING STICK
has a definite region and definite line of LNEE CLS:
study in view, but every animal seen should be noted. The habitat, adapta-
tion by structure and habits to the environment, relations to other animals,
classification of animals seen, should be some of the ideas guiding the study.
The excursions may be divided somewhat as follows, according as opportunities
offer: Upland woods, lowland woods, upland pastures, fields, swamps, a fresh-
water lake, a pond, lower sea beach, higher sea beach, sand hills along shore,
roadside, garden, haunts of birds, insect visits to flowers, ground insects,
insects in logs.

72 BEGINNERS’ ZOOLOGY

Collecting Insects.—In cities and towns insects, varying
with the season, are attracted by electric lights. Beetles
and bugs will be found under the lights, moths on posts
near the lights, grasshoppers and crickets and other in-
sects in the grass near by. A lamp placed by a window
brings many specimens. In the woods and in rocky
places insects are found under logs and stones, and under
the bark of dead trees. Inopen places, prairies, meadows,
and old fields with grass and flowers, it will be easy to find
erasshoppers, butterflies, and some beetles. Ponds and
streams are usually rich in animal forms, such as bugs and
beetles, which swim on or under the surface, and larve
of dragon flies crawling on the bottom. Dragon flies and
other insects that lay eggs on the water are found flying
in the airabove. (In the spring, newly hatched crayfish,
tadpoles, and the eggs of frogs and toads should also be
collected, if found.) Moths may be caught at night by
daubing molasses or syrup made from brown sugar upon
the trunks of several trees, and visiting the trees at in-
tervals with a lantern.

An insect net for catching butterflies and for dredging
ponds may be made by bending a stout wire into a circle
one foot in diameter, leaving enough straight wire to
fasten with staples on an old broomstick. To the frame
is fastened a flour sack, or cone made of a piece of mos-
quito netting.

Butterflies and moths should be promptly killed, or
they will beat their wings to pieces. The quickest method
is by dropping several drops of gasoline upon the ventral
(under) side of the thorax and abdomen, (Caution:
Gasoline should never be used near an open fire, or lamp,
as explosions and deaths result from the flame being led
through the gasoline-saturated air to the vessel containing

it.)

INSECTS 73

A cigar box and a bottle with a notched cork may be
used for holding specimens. Cigar boxes may be used for
holding collections of dried insects. Cork or ribbed
packing paper may be fixed in the bottom for supporting
‘the insect pins. Moth balls or tobacco may be placed
in each box to keep out the insect pests which infest col-
lections.

Captured insects which, in either the larval or the per-
fect stage, are injurious to vegetation, should always be
killed after studying their actions and external features,
even if the internal structure is not to be studied. Bene-
ficial insects, such as ladybugs, ichneumon flies, bees,
mantis (devil’s horse), dragon flies, etc., should be set
free uninjured.

ANATOMY AND GENERAL CHARACTERISTICS OF THE CLASS
INSECTA

The body of an insect is divided by means of two marked
narrowings into three parts: the head, the chest, and the
abdomen.

The head is a freely movable cap-
sule bearing four pairs of append-
ages. Hence it is regarded as
having been formed by the union
of four rings, since the ancestor of
thé insects is believed to have -con-
sisted of similar rings, each ring
bearing a pair of unspecialized legs. Fic. 122.—YELLOw FEVER

The typical mouth parts of an Ree: ae ee <i
insect (Fig. 123) named in order
from above, are (1) an upper lip (labrum, o/), (2) a pait

74

BEGINNERS’ ZOOLOGY

of biting jaws (mandibles, of), (3) a pair of grasping
jaws (maxillz, A, B), and (4)a lower lip {(labium, 2, a, b).

FIG. 123. — MOUTH
PARTS OF BEETLE.

The grasping jaws bear two pairs of
jointed jaw fingers (maxillary palpi,
D, C), and the lower lip bears a pair
of similar lip fingers (labial palpi, @).
The biting jaws move sideways; they
usually have several pointed notches
which serve as teeth. Why should the
grasping jaws be beneath the chewing
jaws? Why is it better for the lower
lip to have fingers than the upper lip?

Why are the fingers (or palpi)

jointed? (Watch a grasshopper
or beetle eating.) Why does an
insect need grasping jaws?
The chest, or thorax, consists
of three rings (Fig. 124) called
the front thorax (prothorax),
middle thorax (mesothorax) and
hind -thorax (metathorax), or
first, second, and third rings.
The
bears

first ring FIG. 124.— EXTERNAL PARTS
OF A BEETLE.
the first

pair of legs, the second ring bears the
second pair of legs and the upper or front
wings, and the third ring bears the third
pair of legs and the under or hind wings.
Thesix feet of insects are characteristic of

Fic. 125.—LEG them, since no other adult animals have that
number, the spider having eight, the cray-
fish and crabs having ten, the centipedes still more, while

OF INSECT.

birds and beasts have less than six. Hence the insects

INSECTS 75

are sometimes called the Six-Footed class (Hexapoda).
The insects are the only animals that have the body in
three divisions. Man, beasts, and birds have cnly two
divisions (head and trunk). Worms are not divided.
Define the class zzsecta by the two facts characteristic of
them (z.e. possessed by them alone), viz.: Insects are ani-
mals with ——— and ———_. Why would it be ambig-
uous to include “hard outer skeleton” in this definition? To
include “bilateral symmetry”? “Segmented body”? The
definition of aclass must zzc/ude all the individuals of the class,
and exclude all the animals that do not belong to the class.

The leg of an insect (Fig. 125) has five joints (two short
joints, two long, and the foot). Named in order from above, they
are (1) the hip (coxa), (2) thigh ring (trochanter), (3) thigh
(femur), (4) the shin (tibia), (5) the foot, which Va
has five parts. Which of the five joints of a
wasp’s leg (Fig. 161) is thickest? Slenderest?
Shortest? One joint (which?) of the foot
(Fig. 161) is about as long as the other four ,, Sieh ae ae
joints of the foot combined. Is the relative Fry, with climbing
length of the joints of the leg the same in pads.
grasshoppers, beetles, etc., as in the wasp (Figs.)? Figure 125 is
a diagram of an insect’s leg cut lengthwise. The leg consists of
thick-walled tubes (0, 2) with their ends held together by thin,
easy-wrinkling membranes which serve as joints. Thus motion is
provided for at the expense of strength. When handling live
insects they should never be held by the legs, as the legs come
off very easily. Does the joint motion of insects most resemble
the motion of hinge joints or ball-and-socket joints? Answer by
tests of living insects. There are no muscles in the foot of an
insect. The claw is moved by a muscle (sm) in the thigh with which
it is connected by the long tendon (z, s, 4, v). In which part are
the breathing muscles? As the wings are developed from folds
of the dorsal skin, the wing has two layers, an upper and a lower
layer. These inclose the so-called “nerves” or ribs of the wing,
each of which consists of a blood tube inclosed in an air tube.

76 BEGINNERS’ ZOOLOGY

The abdomen in various species consists of from five
to eleven overlapping rings with their foldlike joints be-
tween them. Does each ring overlap the ring in front
or the one behind it?

The food tube (Fig. 127) begins at the mouth, which
usually bears salivary glands (4, Fig. 127, which repre-
sents internal organs of the grasshopper). The food tube
expands first into a croplike enlargement; next to this
is an organ (6, Fig. 127), which resembles the gizzard

FIG. 127. — VISCERA OF
GRASSHOPPER. Key
in text. Compare with
Fig. 114. Fic. 128. — AIR TUBES OF INSECT.

in birds, as its inner wall is furnished with chitinous teeth
(6, Fig. 114). These reduce the food fragments that were
imperfectly broken up by the biting jaws before swallow-
ing. Glands comparable to the liver of higher animals
open into the food tube where the stomach joins the small
intestine. At the junction of the small and the large intes-
tine (9) are a number of fine tubes (8) which correspond to
kidneys and empty their secretion into the large intestine.

The breathing organs of the insects are peculiar to
them (see Fig. 128). They consist of tubes which are

INSECTS 77

kept open by having in their walls continuous spirals of
horny material called chz¢zz. Most noticeable are the
two large membranous tubes filled with air and

situated on each side of the body. Do these yy
tubes extend through the thorax? (Fig.128.) The } j i
air reaches these two main tubes by a number LW
of pairs of short windpipes, or ¢vacheas, which ea) oe
begin at openings (spiracles). In which division ete
are the spiracles most numerous? (Fig. 128.) 74

Which division is yy. ot

Ah, AWK. wed . without spiracles? — Isszct's
: l\ ie Could an insect ay.
ee be drowned, z.e.
L smothered, by holding its
body under water? Could
FIG. 130.— DIAGRAMS OF EVOLUTION, A ¢
OF PERICARDIAL Sac around in- it be drowned by immersing
sect’s heart from a number of veins all of it but its head? The
anes motion of the air through
the breathing tubes is caused by a bellowslike motion of the
abdomen. This is readily observed in grasshoppers, beetles,
and wasps. As each ring slips into the ring in front of it,
the abdomen is shortened, and the impure air, laden with
carbon dioxide, is forced out. As the rings slip out, the
abdomen is extended

and the fresh air comes

in, bringing oxygen.
The Circulation. —
Near the dorsal surface FIG. 131.— POSITION OF INSECT’S HEART,
of the abdomen (Fig. food tube, and nerve chain.
131) extends the long, slender heart (Fig. 129). The heart
has divisions separated by valvelike partitions. The blood
comes into each of the heart compartments through a pair
of openings. The heart contracts from the rear toward

78 BEGINNERS’ ZOOLOGY

the front, driving the blood forward. The blood contains
bodies corresponding to the w/#zte corpuscles of human
blood, but lacks the red corpuscles and the red colour. The
blood is sent even to the wings. The veins in the wings
consist of horny tubes inclosing air tubes surrounded
by blood spaces, and the purification of the blood
takes place throughout the course
of the circulation. Hence the im-
perfect circulation is no disadvan-
tage. The perfect provision for
supplying oxygen explains the
remarkable activity of which in-
sects are capable and their great
strength, which, considering their
size, is unequalled by any other
animals.

FIG. 132. — NERVOUS Sys- The Nervous System. — The
‘TEM OF BEE.

heart in backboned animals, e.g.
man, is ventral and the chief nerve trunk is dorsal. As
already stated, the heart of an insect is dorsal; its chief
nerve chain, consisting of a double row of ganglia, is near
the ventral surface (Fig. 131). All the ganglia are below
the food tube except the first pair in the head, which are
above the gullet. This pair may be said to
correspond somewhat to the brain of backboned
animals ; the nerves from the eyes and the feelers
lead to it. With social insects, as bees and

ants, it is large and complex (Fig. 132). In a
typical insect they are the largest ganglia.

FIG. 133.-—
The Senses. — The sense of sae// of most in- FEELER
of a beetle.

sects is believed to be located in the feelers.
The organ of heaving is variously located in different in-
sects. Where is it in the grasshopper? The organs of

INSECTS 79

sight are highly developed, and consist of two compound
eyes on the side of the head and three simple eyes on the
top or front of the head between the com-
pound eyes. The simple eye has nerve
cells, pigments, and a lens resembling
the lens in the eyes of vertebrates (Fig.
134). The compound eye (Fig. 135) has
thousands of facets, usually hexagonal,
on its surface, the facets being the outer ie Sica
ends of. cones which have their inner insect.
ends directed toward the centre of the = Z, lens: ¥, optic
eye. It is probable that the large, or cat
compound, eyes of insects only serve to distinguish poche
objects from dark objects. The simple eyes afford dis-
tinct images of objects within a
few inches of the eye. In gen-
eral, the sight of insects, contrary
to what its complex sight organs
would lead us to expect, is not at
all keen. Yet an insect can fly
through a forest without striking
a twig or branch. Is it better for
the eyes that are immovable in

FIG. 135. COMPOUND EYE
pee Suc the head to be large or small?

1, hexagonal facets of crystalline Which has comparatively larger

cones. 6, blood vessel in optic nerve,

eyes, an insect or a beast?
Inherited Habit, or Instinct. — Insects and other ani-
mals inherit from their parents their particular form of
body and of organs which perform the different functions.
For example, they inherit a nervous system with a struc-
ture similar to that of their parents, and hence with a ten-
dency to repeat similar impulses and acts. Repeated acts
constitute a habit, and az cnherited habit is called an tn-

80 BEGINNERS’ ZOOLOGY

stinct. Moths, for example, are used to finding nectar in
the night-blooming flowers, most of which are white. The
habit of going to white flowers is transmitted in the struc-
ture of the nervous system; so we say that moths have
an instinct to go to white objects; it is sometimes more
obscurely expressed by saying they are attracted or drawn
thereby.

Instincts are not Infallible.— They are trustworthy in
only one narrow set of conditions. Now that man makes
many fires and lights at night, the instinct just mentioned
often causes the death of the moth. The instinct to
provide for offspring is necessary to the perpetuation of
all but the simplest animals. The dirt dauber, or mud
wasp, because of inherited habit, or instinct, makes the
cell of the right size, lays the egg, and provides food for
offspring that the mother will never see. It seals stung
and semiparalyzed spiders in the cell with the egg. If
you try the experiment of removing the food before the
cell is closed, the insect will bring more spiders; if they
are removed again, a third supply will be brought; but if
taken out the third time, the mud wasp will usually close
the cell without food, and when the egg hatches the grub
will starve.

The Development of Insects.-The growth and the moult-
ing of the grasshopper from egg toadult has been stud-
ied. All insects do not develop exactly by this plan. Some
hatch from the egg in a condition markedly different from
the adult, The butterfly’s egg produces a wormlike cater-
pillar which has no resemblance to the butterfly. After
it grows it forms an inclosing case in which it spends a
quiet period of development and comes out a butterfly.
This change from caterpillar to butterfly is called the
metamorphosis. The life of an insect is divided into four

INSECTS . 81

stages: (1) egg, (2) larva, (3) pupa, and (4) émago, or per-
fect insect (Figs. 136, 137, 138).

The egg stage is one of development, no nourishment
being absorbed. The larval stage is one of voracious feed-
ing and rapid growth. In the pupa.
stage no food is taken and there is
no growth in size, but rapid devel-
opment takes place. In the per-
fect stage food is eaten, but no
growth in size takes place. In this py, 136.— Measuring worm,
stage the eggs are produced. When the larva of a moth.

there is very little resemblance between
the larva and the imago, and -no pupal stage,
the metamorphosis, or change, is said to be
complete. When,as with the grasshopper, no
very marked change takes place between the
larva and the imago, there being no pupal
yew ea are stage, the metamorphosis is said to be in-
ofa mosquito, Complete. By studying the illustrations and
specimens, and by thinking of your past observations of
insects, determine which of the insects in the following list
have a complete metamorphosis: beetle, house fly, grass-
hopper, butterfly, cricket, wasp.

FIG. 138. — THE FOUR STAGES OF A BOTFLY, all enlarged.

a, egg on hair of horse (bitten off and swallowed); 4, larva; c, larva with hooks for holding
to lining of stomach; d, pupal stage, passed in the earth; e, adult horse fly.

82 BEGINNERS’ ZOOLOGY

RECOGNITION-CHARACTERS FOR THE PRINCIPAL
ORDERS OF ADULT WINGED INSECTS

(All are wingless when young, and wingless adult forms occur
in all the orders: order Aprera lacks wing-bearing thoracic
structures. )

A single pair of wings is characteristic of the order Dirrera.

A jointed beak, that is sheath-like, inclosing the other mouth
parts, is characteristic of the order HEMIPTERA.

A coiled sucking proboscis and a wing covering of dust-like
microscopic scales are characteristic of the order LEPIDOPTERA.

Horny sheath-like fore wings, covering the hind wings and
meeting in a straight line down the middle of the back, will dis«
tinguish the order CoLEopTERA.

Hind wings folded like a fan beneath the thickened and over-
lapping fore wings, will distinguish most members of the order
ORTHOPTERA.

The possession of a sting (in females) and of two pairs of thin
membranous wings — the small hind wing hooked to the rear mar-
gin of the fore wing — will distinguish the common HyMENOPTERA.

Besides these, there remain a number of groups most of which
have in the past been included under the order NEuRopreERA,
among which the Mayflies will be readily recognized by the lack
of mouth parts and by the possession of two or three long tails ;
the dragon flies by the two pairs of large wings, enormous eyes, and
minute bristle-like antennz ; the scorpion flies, by the possession
of a rigid beak, with the mouth parts at its tip; the caddis flies,
by their hairy wings and lack of jaws; the lace wings, by the
exquisite regularity of the series of cross veins about the margin
of their wings, etc.

INSECTS 83

FIG, 139.— MAY FLY. What order (see table) ?

Exercise in the Use of the Table or Key. —
Write the name of the order after each of the fol-
lowing names of insects : —

|

Wasp (Fig. 122 House fly (Fig. 172)

Weevil (Fig. 163) , Flea (Pig: 173)

Squash bug ( Fig. 184) Silver scale or earwig

Ant lion (Fig. 170) (Fig. 140)

Dragon fly (Fig. 177) Codling moth (Fig-141) Fic. 140. — SILVER
Ichneumon fly (Fig. 159) Botfly (Fig. 138) SCALE. (Order?)

Moths and Butterflies. — Order Mo W hiys 2 Cp 82)?

The presence of scales on the wings is a never-failing
test of a moth ora butterfly. The wings do not fold at all.
They are so large and the legs so weak and delicate
that the butterfly keeps its balance with difficulty when
walking in the wind.

The maxillz are developed to form the long sucking
proboscis. How do they fit together to form a tube?
(See Fig. 147.) The proboscis varies from a fraction of an
inch in the “ miller” to five inches in some tropical moths,
which use it to extract nectar from long tubular flowers.
When not in use, it is held coiled like a watch spring under
the head (Fig. 148). The upper lip (labrum), under lip
(labium), and lip fingers (labial palpi) are very small, and
the mandibles small or wanting (Fig. 146).

The metamorphosis is complete, the contrast between
the caterpillar or larva of the moth and the butterfly and
the adult form being very great. The caterpillar has the
three pairs of jointed legs typical of insects; these are

84 BEGINNERS’ ZOOLOGY

found near the head (Fig. 141). It has also from three
to five pairs of fleshy unjointed proplegs, one pair of
which is always on the last segment. How many pairs
of pro-legs has the silkworm caterpillar? (Fig. 143.)
The measuring worm, or looper? (Fig. 136.) The pupa
has a thin shell. Can you see external signs of the
antenne, wings, and legs in this stage?~ (Fig. 143.) The
pupa is concealed by protective coloration and is some-
times inclosed in a silken cocoon which was spun by the
caterpillar before the last moult. Hairy caterpillars are
uncomfortable for birds to eat. The naked and brightly
marked ones (examples of warning coloration) often con-
tain an acrid and distasteful fluid. The injuries from
lepidoptera are done in the caterpillar stage. The codling
moth (Fig. 141) destroys apples to the estimated value of
$6,000,000 annually. The clothes moth (Fig. 171) is a
household pest. The tent caterpillar denudes trees of their
leaves. The only useful caterpillar is the silkworm (Fig.
143). In Italy and Japan many of the country dwellings
have silk rooms where thousands of these caterpillars are
fed and tended by women and children. Why is the cab-
bage butterfly so called? Why can it not eat cabbage?
Why does sealing clothes in a paper bag prevent the
ravages of the clothes moth?

Flight of Lepidoptera. — Which appears to use more ex-
ertion to keep afloat, a bird or a butterfly? Explain why.
Of all flying insects which would more probably be found
highest up mountains? How does the butterfly suddenly
change direction of flight? Does it usually fly in a straight
or a zigzag course? Advantage of this? Bright colours are
protective, as lepidoptera are in greatest danger when at
rest on flowers. Are the brightest colours on upper or
under side of wings of butterfly? Why? (Think of the

INSECTS 85

colours in a flower.) Why is it better for moths to hold
their wings flat out when at rest? Where are moths dur-
ing the day? How can you test whether the colour of the
wings is given by the scales?

State how moths and butterflies differ in respect to:
body, wings, feelers, habits.

Insects and Flowers. — Perhaps we are indebted to in-
- sects for the bright colours and sweet honey of flowers.
Flowers need insects to carry their pollen to other flowers,
as cross-fertilization produces the best seeds. The insects
need the nectar of the flowers for food, and the bright
colours and sweet odours are the advertisements of the
flowers to attract insects. Flowers of brightest hues are
the ones that receive the visits of insects. Moths, butter-
flies, and bees carry most pollen (see Beginners’ Botany,
Chap. VI).

Comparative Study. — Make a table like this, occupying entire page
of notebook, leaving no margins, and fill in accurately : —

Grass- | BuTTER- Fly Dracon | BEETLE BEE
HOPPER FLY PP. 92; 93 FLY, p. 93] Pp. 90, 91 | pp. 88, 89

of wings

Number and kind
Description of legs

Antenne (length,
shape, joints)

mouth parts

Complete or incom-
plete metamor-
phosis

Biting or sucking Sty |

86 Illustrated Studies

FIG, 142. CABBAGE BUTTERFLY, male
and female, larva and pupa,

FIG. 141. CODLING Moru, from egg to
adult. (See Farmers’ Bulletin, p. 95.)

vUVUYW

(

Fic. 144.— SCALES FROM
BUTTERFLIES’ WINGS, as
Fic, 143. — LIFE HISTORY OF SILKWORM, seen under microscope.

Illustrated Studies

To THE TEACHER: These illustrated studies require
slower and more careful study than the text.. One, or at
most two, studies will suffice for a lesson. The questions can
be answered by studying the figures.

FIGS. 141-148. [Illustrated Study of Lepidoptera. —
Study the stages in the development of codling moth, silk-
worm moth, and cabbage butterfly.

Where does each lay its eggs? What does the larva of
each feed upon? Describe the pupa of each. Describe
the adult forms. Find the spiracles and prolegs on the
silkworm. Compare antenne of moth and _ butterfly.
Which has larger body compared to size of wings ?

Describe the sca/es from a butterfly’s wings as seen under
microscope (144). How are the scales arranged on moth’s
wing (145) ? By what part is scale attached to wing? Do
the scales overlap ? ;

Study butterfly’s head and frodoscis (Figs. 146-148).
What shape is compound eye? Are the antennz jointed ?
Is the proboscis jointed? Why not call it a tongue?
(See text.)

Which mouth parts have almost disappeared? What is
the shape of cut ends of halves of proboscis? How are
the halves joined to form a tube ?

If you saw a butterfly on a flower, for what purpose
would you think it was there? What, if you saw it ona
leaf? How many spots on fore wing of female cabbage
butterfly ? (Fig. 124, above.)

Does the silkworm chrysalis fill its cocoon ?

Fic. 148. —HEAD
OF BUTTERFLY
(side view).

FIG. 145.— SCALES
ON MOTH’s WING.

FIG. 146.— HEAD
OF BUTTERFLY,

FIG. 147.— SECTION
OF PROBOSCIS of
butterfly showing
lapping .jomt and
dovetail joint.

88 Illustrated Studies

FIGS. 149-161. Illustrated
Study of Bees and their Kin-
dred. — Head of worker (Fig.
149): 0, upper lip; of, chew-
ing jaws; wk, grasping jaws;
At, jaw finger: @, lip finger;
z, tongue.

How do heads of drone
(150) and queen (151) differ FIG. 158.—- Anatomy of bee.
as to mouth, size of the two .
compound eyes, size and position of the three simple eyes? Is the head of a
worker more like head of drone or head of queen? Judging by the head, which
is the queen, drone, and worker in Figs. 154-156? Which of the three is largest ?
Smallest? Broadest ?

Figure 152 shows hind leg of worker. What surrounds the hollow, ws, which
serves as pollen basket? The point, £%, is a tool for removing wax which is
secreted (c, Fig. 157) between rings on abdomen. In Fig. 158, find relative
positions of heart, v, food tube, and nerve chain. Is crop, /, in thorax or abdo-

men? In this nectar is changed to honey, that it may not spoil. Compare
nerve chain in Fig. 132,

Illustrated Studies 89

Compare the cells of
bumble bee (Fig. 153) with
those of hive bee. They
differ not only in shape but
in material, being made of
web instead of wax, and
they usually contain larvae
instead of honey. Onlya
few of the queens among
bumble bees and wasps
survive the winter. How
do ants and honey bees
provide for the workers
also to survive the win-
ter? Name all the social
insects that you can think of. Do
they all belong to the same order?

The ichneumon fly shown enlarged in
Fig. 159 lays its eggs under a caterpillar’s
skin. What becomes of theeggs? The
true size of the insect is shown by the
cross lines at a. The eggs are almost
microscopic in size. The pupze shown
(true size) on caterpillar are sometimes
mistaken for eggs. The same mistake is
made about the pupa cases of ants.
Ichneumon flies also use tree-borers as
“hosts” for their eggs and larva. Is
this insect a friend of man ?

The digging wasp (Figs. 160 and 161)
supplies its larva with caterpillars and
closes the hole, sometimes using a stone
as pounding tool. Among the few
other uses of tools among lower
animals are the elephant’s use
of a branch for a fly brush, and
the ape’s use of a walking stick.
This wasp digs with fore feet
like a dog and kicks the dirt
out of the way with its hind
feet.

Are the wings of bees and
wasps more closely or less
closely veined than the wings
of dragon flies? (Fig. 177.)

FIG. 161.— Wasp using pebble.

From Peckham’s “ Solitary Wasps,”
Houghton, Mifflin & Co.

90 Illustrated Studies

Illustrated
Study of
Beetles.

FiG. 162, — Diving beetle (Dytiscus), with larva, a,

at 7

FIG. 167. — MAY BEETLE.

~ Sk “ke aA ©

FIG. 169. — Colorado beetle (potato bug).

Illustrated Studies QI

Illustrated Study of Beetles (Figs. 162-169).— Write the life history of the
Colorado beetle, or potato bug (Fig. 169), stating where the eggs are laid and describ-
ing the form and activities of each stage (the pupal stage, 4, is passed in the ground).

Do the same for the May deetle (Figs. 167-168). (It is a larva—the white
grub—for three years; hogs root them up.) Beetles, like moths, may be trapped
with a lantern set above a tub of water.

Where does a Scaraé (or sacred beetle of the Egyptians), also called tumble
bug (Fig. 164), lay its eggs (Fig. 165)? Why?

How does the click beetle, or jack snapper (Fig. 166), throw itself into the air ?
For what purpose ?

The large proboscis of the weevil (Fig. 163) is used for piercing a hole in which
an egg is laid in grain of corn, boll of cotton, acorn, chestnut, plum, ete.

How are the legs and body of the diving beetle suited for swimming (Fig. 162)?
Describe its larva.

What is the shape of the lady bug (Fig.97)? It feeds upon plant lice (Fig. 185).
Is any beetle of benefit to man ?

deo 2 ~
Fic. 170. — Life history of ant lion.

Illustrated Study of Ant Lion, or Doodle Bug (Fig. 170).— Find the pitfall
(what shape ?); the larva (describe it) ; the pupa case (ball covered with web and
sand); the imago. Compare imago with dragon fly (Fig. 177).

How does ant lion prevent ant from climbing out of pitfall (see Fig. 170)?
What is on edge of nearest pitfall ? Explain.

: Ant lions may be kept in a box half filled with sand and fed on ants. How is
the pitfall dug? What part of ant is eaten? How is unused food removed ?
How long is it in the larval state? Pupal state? Keep net over box to pre-

vent adult from flying away when it emerges,

92 Illustrated Studies

Fic. 172. — Metamor-
phosis of house fly
(enlarged).

FIG. 174.— Louse and
its eggs attached to a
hair. Natural size
and magnified.

FiG. 175.— Bed bug. x5. Fic. 176. -— Life history of mosquito.

Illustrated Studies 93

¥

Illustrated Study of Insect Pests (Figs. 171-176).— Why does the clothes
moth (171) lay its eggs upon woollen clothing ? How does the larva conceal itself ?
The larva can cut through paper and cotton, yet sealing clothes in bags of paper
or cotton protects them. Explain.

The house fly eats liquid sweets. It lays its eggs in horse dung. Describe its
larval and pupal forms. Banishing horses from city would have what beneficial
effect ?

Describe the Jowse and its eggs, which are shown attached to a hair, natural size
and enlarged.

Describe the ded bug. Benzine poured in cracks kills bed bugs. Do bed
bugs bite or suck ?. Why are they wingless ?

Describe the larva, 4, pupa, g, and the adult flea, all shown enlarged. Its
mandibles, 4, 4, are used for piercing. To kill fleas lather dog or cat completely
and let lather remain on five minutes before washing. Eggs are laid and first
stages passed in the ground.

How does the mousguito lay its eggs in the water without drowning (176) ? Why
are the eggs always laid in still water ? Which part of the larva (wiggletail) is held
to the surface in breathing ? What part of the pupa (called tumbler, or bull head)
is held to the surface in breathing ? Give differences in larva and pupa. Where
does pupa change to perfect insect? Describe mouth parts of male mosquito (at
left) and female (at right). Only female mosquitoes suck blood. Males suck
juice of plants. Malarial mosquito alights with hind end of body raised at an

angle. Why does killing fish and frogs increase mosquitoes? 1 oz. of kerosene for 15 ft..
of surface of water, renewed monthly, prevents mosquitoes.

What is the use to the squash bug (Fig. 184) of having so bad an odour?

4 2 5 % 6

FIG. 177. Ilustrated Study of Dragon Fly.—3 shows dragon fly laying its
eggs in water while poised on wing. Describe the larval form (water tiger). The
extensible tongs are the maxillae enlarged. The pupa (r) is active and lives in
water. Where does transformation to adult take place (5)? Why are eyes of
adult large? its legs small? Compare front and hind wings.

Do the eyes touch each other? Why is a long abdomen useful in flight ?
Why would long feelers be useless? What is the time of greatest danger in the
development of the dragon fly? What other appropriate name has this insect ?
Why should we never kill a dragon fly ?

94 Illustrated Studies

FIG. 179. — Trap-door
spider.

FIG. 182.— Laying egg. FIG, 183.— Foot of spider.

Illustrated Study of Spiders (Figs. 178-183).— The tarantula, like most spi-
ders, has eight simple eyes (none compound), Find them (Fig. 178). How do
spiders anda insects differ in body ? Number of legs? Which have more joints to
legs? Does trap-door spider hold the door closed (Fig. 179)? How many pairs
of spinnerets for spinning web has a spider (.Sfw, 180) ? Foot of spider has how
many claws? How many combs on claws for holding web? Spiders spin a
cocoon for holding eggs. From what part of abdomen are eggs laid {Z, 182;
2,181) ? Find spider's air sacs, @u, Fig. 181; spinning organs, sf; fang, 47; poison
gland, 2; palpi, 44; eyes, az; nerve ganglia, og, ug; sucking tube, s7; stomach, a
intestine, ma; liver, Ze; heart, 4, (black); vent, a. Give two reasons why a spider
is not an insect. How does it place its feet at each step(Fig. 110)? (Does the
size of its nerve ganglia indicate great or little intelligence ? Why do you think
first part of body corresponds to both head and thorax of insects ?

INSECTS 95

The following Farmer’s Bulletins, (revised to 1921)
are available for distribution to those interested, by
the United States Department of Agriculture, Washington,
D.C.—

Farmer’s Bulletin No. 47, Insects Affecting the Cotton
Plant; No. 447, Bee Keeping; No. 440, The Peach Twig
Borer; No. 120, The Principal Insects Affecting the
Tobacco Plant; No. 856, Important Insecticides; No. 835,
The Principal Insect Enemies of Growing Wheat;
No. 799, Carbon Bisulphide as an Insecticide; No. 243,
Insecticides and Fungicides; No. 152 (revised) Mange
in Cattle; No. 155, How Insects Affect Health in Rural
Districts; No 492, The Control of the Codling Moth;
No. 172, Scale Insectsand Mites on Citrus Trees; No. 196,
Usefulness of the Toad; No. 209, Controlling the Boll
Weevil in Cotton Seed and at Ginneries; No. 211, The
Useof Paris Green in Controlling the Cotton Boll
Weevil; No. 872, The Cotton Bollworm; No. 848, The
Control of the Boll Weevil; No. 223, Miscellaneous
Cotton Insects in Texas; No. 908, The Control of the
Codling Moth and Apple Scab.

Bulletins of the Bureau of Entomology may _ be
obtained from the same source, while the supply lasts,
as follows:

Destructive Locusts; The Honey Bee; The San José
Scale; The Principal Household Insects of the United
States; The Gypsy Moth in America; The Periodical
Cicada; The Chinch-Bug; The Hessian Fly; Insects
Injurious to Vegetables; Notes on Mosquitoes; Some
Insects Attacking the Stems of Growing Wheat, Rye,
Barley, and Oats.

96 BEGINNERS’ ZOOLOGY

Bulletins on Similar Topics, Published by the Depart-
ment of Agriculture, Ontario—
(Write to the Publications Branch)

Bulletin No. 187—The Codling Moth

Bulletin No. 195—The Insecticides and Fungicides
Bulletin No. 198—Lime Sulphur Wash

Bulletin No. 219--The San José and Oyster-shell Scales
Bulletin No: 241—Peach Growing in Ontario
Bulletin No. 250—Insects Attacking Fruit Trees
Bulletin No. 251—Insects Affecting Vegetables
Bulletin No. 256—The Wintering of Bees

Bulletin No. 257—The More Important Fruit Tree
Diseases in Ontario

Bulletin No. 258—The More Important Fungus and
Bacterial Diseases of Vegetables in Ontario

Bulletin No. 271—The Apple Maggot

Bulletin No. 276—Bee Diseases in Ontario

Bulletins Published by the Department of Agriculture,
Ottawa—
(Write to the Publications Branch)

Bulletin No. 9—The Army Worm

Bulletin No. 10—Cutworms and their Control

Bulletin No. 26—Bees and How to Keep Them

Circular No. 9—1921—Common Garden Insects and
their Control

Pear! divers.

CrrAPUER IX
MOLLUSCS

THE FRESH-WATER MUSSEL

SuccEstions. — The mussel is usually easy to procure from
streams and lakes by raking or dredging. In cities the hard-
shelled clam, or quahog, is for sale at the markets, and the follow-
ing descriptions apply to the anodon, unio, or quahog, with
slight changes in regard to the siphons. Mussels can be kept
alive for a long time in a tub with sand in the bottom. Pairs of
shells should be at hand for study.

External Features. — The shell is an elongated oval,
broader and blunter at one end (Fig. 188). Why does
the animal close its shell? Does it open the shell?
Why? Does it thrust the foot forward and pull up to it,
or thrust the foot back and push? (Mussels and clams
have no bones.) Does it go with the blunt end or the more
tapering end of the shell forward? (Fig. 188.) Can a
mussel swim? Why, or why not?

97

98 BEGINNERS’ ZOOLOGY

Lay the shells, fitted together, in your hand with the hinge
side away from you and the blunt end to the left (Fig. 188).
Is the right or the left shell
uppermost? Which is the
top, or dorsal, side? Which
is the front, or anterior,
end? Is the straight edge
at the top or at the bottom ?
Our word “ valve” is derived

FIG. 188.— ANODON, or fresh-water | from a word meaning shell,

eee because the Romans used
shells for valves in pumps. Is the mussel a univalve ora
bivalve ? Which kind is the oyster? The snail?

Does the mussel have bzlateral symmetry? Can you
find a horn» covering, or epidermis, over the limy shell
of a fresh specimen? Why is it necessary? Does water
dissolve lime? Horn? Finda bare spot. Does any of
the shell appear to be missing there ?

The bare projection on each shell is called the zo.
Is the umbo near the ventral or the dorsal line? The
posterior or anterior end? Is
the surface of the umbones
worn? Do the umbones rub
against the sand as the mussel
ploughs its way along? How are
the shells held together? Where
is the igament attached? (Fig.
189.) Is it opposite the um- Fic. 189.—DIAGRAM OF SHELL
bones or more to the front or ° page ai pare
to the rear? Fig.189.) Is the liga-
ment of the same material as the shell? Is the ligament
in a compressed condition when the shell is open or when
it is closed? (Fig. 189.) When is the muscle relaxed?

MOLLUSCS 99

Notice the mes on the outside of the shell (Figs. 188
and 190). What point do they surround? They are /ves
of growth. Was each line once the
‘margin of the shell? If the shell
should increase in size, what would
the present margin become? (Fig.
191.) Does growth take place on
the margin only? Did the shell
grow thicker as it grew larger?
Where is it thinnest ? FIG. 190.— MUSSEL crawl-

Draw the outside of the shell from SUD EEE
the side. Draw a dorsal view. Near the drawings write the
names of the margins of the shell (p. 98) and of other parts
learned, using lines to indicate the location of the parts.

Study the surface of the shell inside and out. The
inside is called mother-of-pearl. Is it of lime? Is the
deeper layer of the shell of lime? (When weak hydro-
chloric acid or strong vinegar is dropped on limy substances,
a gas, carbon dioxide, bubbles up.) Compare the thickness
of the epidermal layer, the middle chalky layer, and the
inner, pearly layer.

Anatomy of the Mussel.— What parts protrude at any
time beyond the edge of the shell? (Fig. 190.) The shell
is secreted by two folds of the outer
layer of the soft body of the mus-
sel. These large, flaplike folds hang
down on each side, and are called

the mantle. The two great flaps

ee ie co enaee of the mantle hang down lower than
ment of muscles as mussel the rest of the body and line the
eau Coe. shell which it secretes (Fig. 1092).
The epidermis of the mantle secretes the shell just as the
epidermis of the crayfish secretes its crust. Can you find

100 BEGINNERS’ ZOOLOGY

the pallial line, or the line to which the mantle extended
on each shell when the animal was alive? A free portion
of the mantle extended like a fringe below the pallial line.

The shells were held together by
; cate two large adductor muscles. The

anterior adductor (Fig. 193) is near
4" the front end, above the foot. The
' posterior adductor is toward the rear
end, but not so near the end as the
anterior. Can you find both muscle
scars in the shells ? Are they nearer
the ventral or the dorsal surface?
The points of attachment travelled

FIG. 192.— CROSS SECTION d d ae h i
OF MussEL. (Diagram, G@OWNward an axe er apart as the
after Parker.) animal grew (see Fig. 191). Higher

= (t
Foor MANTLES

than the larger scars are small scars, or impressions, where
the protractor and retractor muscles that extend and draw
in the foot were attached.

The muscular foot extends downward in the middle, half-
way between the shells (Fig. 193). On each side of the
foot and behind
it hang down

the two pairs of
gills, the outer
pair and the in-

ae RSS STE ADDN MUS),
fe —

ner pair (Fig.
192). They may
be compared to
four V-shaped FIG. 193. — ANATOMY OF MUSSEL. (Beddard.)
troughs with

their sides full of holes. The water enters the troughs
through the holes and overflows above. Is there a marked

difference in the size of the two pairs of gills? A kind of

MOLLUSCS IOI

chamber for the gills is made by the joining of the mantle
flaps below, along the ventral line. The mantle edges are
separated at two places, leaving openings called erhalent
and zxhalent stphons.

Fresh water with its oxygen, propelled by cz/za at the
opening and on the gills, enters through the lower or
inhalent siphon, passes between the gills, and goes to an
upper passage, leaving the gill chamber by a slit which
separates the gills from the foot.
For this passage, see arrow
(Hig. toa). Phe movement of
the water is opposite to the way
the arrow points. After going
upward and backward, the water
emerges by the exhalent siphon.
The gills originally consisted of
a great number of filaments.
These are now united, but not
completely so, and the gills still
have a perforated or lattice

FIG. 194. — MUSSEL.
A, left shell and mantle flap removed.

structure. Thus they present a B, section through body.
0 ae Question: Guided by other figures,
large surface for absorbing oa, identify the parts to which lines are

gen from the water. drawn.

The mouth is in front of the foot, between it and the
anterior adductor muscle (Fig. 194). On each side of the
mouth are the /adcal palps, which are lateral lips (Fig. 195).
They have cilia which convey the food to the mouth after
the inhalent siphon has sent food beyond the gill chamber
and near to the mouth. Thus both food and oxygen enter
at the inhalent siphon. The foot is in the position of a
lower lip, and if regarded as a greatly extended lower lip,
the animal may be said to have what is to us the absurd
habit of using its lower lip as a foot. The foot is some-

102 BEGINNERS’ ZOOLOGY

times said to be hatchet-shaped (Fig. 195). Do you see
any resemblance? Does the foot penetrate deep or shal-
low into the sand? (Fig.190.) Why,
or why not?

The food tube of the mussel is com-
paratively simple. Behind the mouth it
enlarges into a swelling called the s/om-
ach (Fig. 393). The bile ducts of the
neighbouring liver empty into the stomach.
The intestine makes several turns in the
substance of the upper part of the foot
and then passing upward, it runs ap-
proximately straight to the vent (or anus),
which is in the wall of the exhalent
siphon. The intestine not only runs
FIG, 195-— MUSSEL. From through the pericardial cavity (celome)

below. Level cut across surrounding the heart, but through the

sass ventricle of the heart itself (Fig. 196).
Se, palp; P, foot; O, mouth; Z

G, liver; Gg, Vg, Pg, gan- The kidneys consist of tubes which

glia. open into the pericardial chamber above
and into the gill chamber below (/Vefi.,
Fig. 193). ‘The tubes are surrounded by
numerous blood vessels (Fig. 198) and
carry off the waste matter from the blood.

The nervous system consists of chree
pairs of ganglia and nerves (Fig. 197).
The ganglia are distinguishable because of
P their orange colour. The pedal
— ganglia on the front of the foot
are easily seen also; the vis-
ceral ganglia on the posterior Fic, 196.— HEART OF
em adductor muscle may be seen MUSSEL, with intestine
without removing the mussel — P#ssing through it.
from the shell (Fig. 193). The reproductive organs
open into the rear portion of the gill cavity (Fig. 193).
The sperms, having been set free in the water, are drawn into
the ova by the same current that brings the food. The eggs

a Oe

3
FIG. 197.

MOLLUSCS 103

are hatched in the gills. After a while the young mussels go out
through the siphon.

Summary. — In ‘the gills (Fig. 198) the blood gains what?
Loses what? From the digestive tube the blood absorbs nourish-
ment. In the kidneys the blood is partly purified by the loss of
nitrogenous waste. |

The cilia of the fringes on the inhalent, or lower, siphon,
vibrate continually and drive water and food particles into
the mouth cavity. Food particles that are brought near the
labial palps are conveyed by them
to the mouth. As the water passes
along the perforated gills, its oxygen
is absorbed ; the mantle also absorbs
oxygen from the water as it passes.
The water, as stated before, goes
next through a passage between the
foot and the palp into the cavity a-
bove the gills and on out through the
exhalent siphon. By stirring the
water, or placing a drop of ink near
the siphons of a mussel keptina tub, py¢. 98. — Diacram oF

: : : MUSSEL CUT ACROSS,
the direction of its flow may be seen. sa
showing mantle, ma; gills,

The pulsations of the heart are 4ie; foot, /; heart, 4; in-
plainly visible in a living mollusc. 9 ““""*

Habits of the Mussel.—Is it abundant in clear or in mud-
dy water; swift, still, or slightly moving water? Describe
its track or furrow. What is its rate of travel? Can you
distinguish the spots where the foot was attached to the
ground? How long is one “step” compared to the length
of the shell? Theanimal usually has the valves opened
that it may breathe andeat. The hinge ligament acts like
the case spring of a watch, and holds the valves open un-
less the adductor muscles draw them together (Fig. 189).

104 BEGINNERS’ ZOOLOGY

When the mussel first hatches from the egg, it has a tri-
angular shell. It soon attaches itself to some fish and thus
travels about. After two months it
drops to the bottom again.

Other Mollusca. — The oysver’s shells
are not an exact pair, the shell which
lies upon the bottom being hollowed
out to contain the body, and the upper
shell being flat. Can you tell by ex-

amining an oyster shell which was the

FIG. 199.— OYSTER.

lower valve? Does it show signs of

Tee eae ny having been attached to the bottom?

gill. The young oyster, like the young mus-

sel, is free-swimming. Like the arthropoda, most molluscs

undergo a metamorphosis to reach
the adult stage (Fig. 199).

Examine the shells of clams,
snails, scallops, and cockles. Make
drawings of their shells. The slug
is very similar to the snail except
that it has no shell. If the shell of the snail shown in
Fig. 202 were removed, there would be left a very good
representation of a slug.

Economic Importance of
Mollusca. — Several species
of clams are eaten. One of
them is the hard-shell clam

FiG. 201.—CyPr#a. (Univalve, | (quahog) found on the At-
with a long opening to shell.)

FIG. 200. — TROCHUS.

lantic coast from Cape Cod
to Texas. Its shell is white. It often burrows slightly
beneath the surface. The soft-shell clam is better liked as
food. It lives along the shores of all northern seas. It
burrows a foot beneath the surface and extends its siphons

MOLLUSCS 105

through the burrow to the surface when the tide is in,
and draws into its shell the water containing animalcules
and oxygen.

Oysters to the value of many millions of dollars are gath-
ered and sold every year. The most valuable oyster fish-
eries of North America are in Chesapeake Bay. The
young oysters, or “spat,” after they attach themselves to
the bottom in shallow water, are transplanted. New oyster
beds are formed in this way. The beds are sometimes
strewn with pieces of rock, broken pottery, etc., to encourage
the oysters to attach themselves. The dark spot in the
fleshy body of the oyster is the digestive gland, or liver.
The cut ends of the tough adductor muscles are noticeable
in raw oysters. The starfish is very destructive in oyster
beds.

Pearls are deposited by bivalves around some irritating
particle that gets between the shell and the mantle. The
pearl oyster furnishes most of the pearls; sometimes
pearls of great: value are obtained from fresh-water

mussels. Name
articles that are

made partly or
wholly of mother-
of-pearl.

Study of a Live
oa on Sing. —Is FIG. 202.—A SNAIL.
ats body dry oe 7, mouth; wf, “f, feelers; e, opening of egg duct; /, foot;
moist ? Do land _ ma, mantle; 2x, opening to lung; a, vent.
snails and slugs have lungs or gills? Why? How many pairs
of tentacles have they? What is their relative length and position?
The eyes are dark spots at bases of tentacles of snail and at the
tips of the rear tentacles of slug. Tduch thé tentacles. What
happens? Do the tentacles simply stretch, or do they turn inside

106 BEGINNERS’ ZOOLOGY

out as they are extended? Is the respiratory opening on the
right or the left side of the body? On the mantle fold or on the body?
(Figs. 202-3-4.) How
often does the aperture
open and close ?

Place the snail in a
moist tumbler. Does
the whole under surface seem to be used in creeping? Does the
creeping surface change shape as the snail creeps? Do any folds
or wrinkles seem to
move either toward the
front or the rear of its
body? Is enough mu-
cus left to mark the
path travelled? The
fold moves to the front,
adheres, and smooths
out as the slug or snail

is pulled forward.
Cephalopods. — The FIG. 204.— CIRCULATION AND RESPIRATION

FIG. 203. —A SLUG.

G IN SNAIL.
highest and best de-
a, mouth; 4, 4, foot; c. vent: ad, d, lung; 4, heart.
veloped molluses are Blood vessels are black. (Perrier.)

the cephalopods, or “head-footed” molluscs. Surrounding the
mouth are eight or ten appendages which serve both as feet and
as arms. These appendages have two rows of sucking disks by
which the animal attaches itself to the sea bottom, or seizes fish
or other prey with a firm grip. The commonest examples are the
squid, with a long body and ten
arms, and the octopus, or devil-
fish, with a short body and
eightarms. Cephalopods have
strong biting mouth parts and
complex eyes somewhat resem-
bling the eyes of backboned,
or vertebrate, animals. The
large and staring eyes add to the uncanny, terrifying appearance.
The sepia or “ink” discharged through the siphon of the squid
makes a dark cloud in the water and favoursits escape from

FIG. 205.—A SQUID.

MOLLUSCS 107

enemies almost as
much as does its swift-
ness (Fig. 205). The
squid sometimes ap-
proaches a fish with
motion so slow as to be
imperceptible, and then
suddenly seizes it, and
quickly kills it by
biting it on the back be-
hind the head.

FIG. 206.— PEARLY NAUTILUS. (Shell sawed
The octopus 1s more through to show chambers used when it was

sluggish than the squid. * smaller, and siphuncle, S, connecting them. Ten-
tacles, 7.)

Large species called
devilfish sometimes have a spread of arms of twenty-five feet.
The pearly nautilus (Fig. 206) and the female of the paper argo-
naut (Fig. 207) are examples of cephalopods that ‘have shells.

The cuttlefish is closely related to the squid.

FIG. 207, — PAPER ARGONAUT (female).
x ¥3 (ze. the animal is three times as long
and broad as figure). NAUT (male). * 1%.

FIG. 208. — PAPER ARGO-

General Questions. — The living parts of the mussel are
very soft, the name mollusca being derived from the
Latin word mollis, soft. Why is it that the softest animals,
the molluscs, have the hardest coverings?

To which class of molluscs is the name acephala (head-
less) appropriate ? Lamellibranchiata (platelike gills)?

108 BEGINNERS’ ZOOLOGY

Why is a smooth shell suited to a clam and a rough
shell suited to an oyster? Why are the turns of a snail’s
shell so small near the centre?

Why does the mussel have no use for head, eyes, or pro-
jecting feelers? In what position of the valves of a mussel
is the hinge ligament in a stretched condition?» How does
the shape of the mussel’s gills insure that the water cur-

rent and the blood current are brought in close contact?
The three main classes of molluscs are: the pelecypoda

(hatchet-footed); gastropoda (stomach-footed); and cepha-

lopoda (head-footed). Give an example of each class.

Comparison of Mollusks

MussEL SNAIL Squip

GRAss-
HOPPER

SPIDER CrAymSH | CENTIPEDE! MusseL

rN ——

Bilateral or radiate

Appendages for lo-
comotion

Names of divisions
of body

Organs and method
of breathing

ES ee ey

Locomotion

CHAPTER X

FISHES

SUGGESTIONS. —
The behaviour of a
live fish in clear
water, preferably in
a glass vessel or an
aquarium, should be
studied. A skeleton may be
prepared by placing a fish in
the reach of ants. Skeletons
of animals placed on ant beds
are cleaned very thoroughly.

The study of the perch, that follows, will apply to almost any other
common fish.

Movements and External Features. — What is the gew-
eral shape of the body of a fish? How does the dorsal, or
upper, region differ in form from the ventral? Is there a
narrow part or neck where the head joins the trunk?
Where is the body thickest? What is the ratio between
the length and the height? (Fig. 209.) Are the right and
the left sides alike? Is the symmetry of the fish bilateral
or radial?

The body of the fish may be divided into three regions-—
the head, the trunk, and the tail. The trunk begins with the
foremost scales; the tail is said to begin at the vent, or
anus. Which regions bear appendages? Is the head
movable independently of the trunk, or do they move
together ? State the advantage or the disadvantage in this.
Is the body depressed (flattened vertically) or compressed

109

110 BEGINNERS’ ZOOLOGY

(flattened laterally)? Do both forms occur among fishes?
(See figures on pages 123, 124.)

How is the shape of the body advantageous for move-
ment? Can a fish turn more readily from side to side, or
up and down? Why? Is the head wedge-shaped or coni-
cal? Are the jaws flattened laterally or vertically? The
fish swims in the water, the bird swims in the air. Account
for the differences in the shape of their bodies.

Is the covering of the body \ike the covering of any ani-
mal yet studied? The scales are attached in little pockets,

AS ( 1

ils wuees

ne cere CLE : mee
= SONS :

FIG, 209. — WHITE PERCH (Morone Americana).

or folds, in the skin. | Observe the shape and size of scales
on different partsof the body. What parts of the fish are
without scales? Examine a single scale; what is its
shape? Do you see concentric lines of growth on a scale?
Sketch a few of the scales to show their arrangement.
What is the use of scales? Why are no scales needed on
the head? How much of each scale is hidden? Is there
a film over the scale? Are the colours in the scale or
on it?

The Fins. — Are the movements of the fish active or
sluggish? Can it remain stationary without using its fins ?

FISHES Itt

Can it move backward? How are the fins set in motion?
What is the colour of the flesh, or muscles, of a fish? Count
the fins. Howmany are in pairs? (Fig. 209.) How many
are vertical? How many are on the side? How many
are on the middle line? Are the paired or the unpaired fins
more effective in balancing the fish? In turning it from
side to side? In raising and lowering the fish? In pro-
pelling it forward? How are some of the fins useful to -
the fish besides for balancing and swimming ?

The hard sfzxes supporting the fins are called the fin
rays. The fin on the dorsal line of the fish is called the
dorsal fin. Are its rays larger or smaller than the rays of
the other fins? The perch is sometimes said to have two
dorsal fins, since it is divided into two parts. The fin
forming the tail is called the tail fin, or caudal fin. Are
its upper and its lower corners alike in all fishes? (Fig. 228.)
On the ventral side, just behind the vent, is the ventral
fin, also called the anal fin. The three fins mentioned are
unpaired fins. Of the four-paired fins, the pair higher on
the sides (and usually nearer the front) are the pectoral
fins. The pair nearer the ventral line are the fe/vic fins.
They are close together, and in many fish are joined
across the ventral line. The ventral fins are compared to
the legs, and the pectoral fins to the arms, of higher verte-
brates. (Fig. 244.) Compare fins of fish, pages 123, 124.

Make a drawing of the fish seen from the side, omit-
ting the scales unless your drawing is very large.

Are the eyes on the top or on the sides of the head, or on
both? Cana fish shut its eyes? Why, or why not? Is the eye-
ball bare, or covered by a membrane? Is the covering of
the eyeball continuous with the skin of the head? Is
there a fold or wrinkle in this membrane or the surround-
ing skin? Has the eyea pupil? Aniris? Is the eye of

112 BEGINNERS’ ZOOLOGY

the fish immovable, slightly movable, or freely movable?
Can it look with both eyes at the same object? Is the
vange of vision more upward or downward? To the front
or the side? In
what direction is
vision impossible?
Can a fish close its
eyes ig sleep? Does
the eyeball appear
spherical or flat-
tened in front?

FIG, 210.— BLACKBOARD OUTLINE OF FISH. The ball is really
spherical, the lens is very convex, and fish are nearsighted.
Far sight would be useless in a dense medium like water.
In what direction from the eyes are the nostrils (Fig.
211.) There are two pair of nostrils, but there isonly one
pair of nasal cavities, with two nostrils opening into each.
There are no nasal passages to
the mouth, as the test with a
probe shows that the cavities do
not open into the mouth. What
two functions has the nosein man?
What function has it in the fish?

There are zo external ears.
The ear sacs are embedded in the

FIG, 211.— HEAD OF CARP,

bones of the skull. Is hearing acute or dull? When you are
fishing, is it more necessary not to talk or to step lightly,
so as not to jar the boat or bank ?

What is the use of the large openings found at the back
of the head on each side? (Fig. 211.) Under the skin at
the sides of the head are thin membrane bones formed from
the skin ; they aid the skin in protection. Just under these
membrane bones are the gill covers, of true bone. Which

FISHES 113

consists of more parts, the membranous layer, or the true
bony layer in the gill cover? (Figs. 211 and 212.)

Is the mouth large or small? Are the éee‘h blunt or
pointed? Near the outer edge, or far in the mouth?
(Fig. 212.) Does the fish have lips? Are the teeth in
one continuous row in either jaw? In the upper jaw
there are also teeth on the premaxillary bones. These
bones are in.front of the maxillary bones, which are with-
out teeth. Teeth are also found inthe roof of the mouth,
and the tongue bears horny appendages similar. to teeth.
Are the teeth of the fish better suited for chewing or for

/ / | /) Zz
MV ZB
(Al iit ; With LZ Vy 2
me y, YY ls iy
WWW

FIG. 212. -SKELETON OF PERCH.

grasping? Why are teeth on the tongue useful? Watch
a fish eating: does it chew its food? Can a fish taste?
Test by placing bits of brown paper and food in a vessel
or jar containing a live fish. Is the throat, or gullet, of the
fish large or small ?

The skeleton of a fish is simpler than the skeleton of
other backboned animals. Study Fig. 212 or a prepared
skeleton. At first glance, the skeleton appears to have
two vertebral columns. Why? What bones does the fish
have that correspond to bones in the human skeleton ?
Are the projections (processes) from the vertebrae long or
short? The 7zbs are attached to the vertebre of the trunk,
the last rib being above the vent. The tail begins at the

114 BEGINNERS’ ZOOLOGY

vent. Are there more tail vertebra or trunk vertebrz ?
Are there any neck (cervical) vertebrae (7.c. in front of
those that bear ribs)? The first few ribs (how many ?) are
attached to the central body of the vertebrz. The re-

FIG. 213.

maining ribs are loosely attached to processes on the
vertebrae. The ribs of bony fishes are not homologous
with the ribs of the higher vertebrates. In most fishes
there are bones called intermuscular bones attached to the
first ribs(how many in the perch?) which are possibly homol-
ogous to true ribs; that is, true ribs in the higher verte-
brates may have been developed from such beginnings.
Which, if any, of the fiz skeletons (Fig. 214) are not
attached to the general skeleton? Which fin is composed
chiefly of tapering, pointed rays? Which fins consist of
rays which sub-
divide and widen
toward the end?
Which kind are
stiff, and which are
flexible? Which of
the fin rays are segmented, or in two portions? The outer

FIG. 214. —SOFT-RAYED AND SPINY-RAYED FINS.

segment is called the radial, the inner the basal segment.
Which segments are longer? There is one basal segment
that lacks a radial segment. Find it (Fig. 212).

FISHES 115

What is the advantage of. the backbone plan of struc-
ture over the armour-plate plan? You have seen the spool-
like body of the vertebra in canned salmon. Is it concave,
flat, or convex at the ends?

The gills are at the sides of the head (Fig. 215) under
the opercula, or gill covers. What is the colour of the gills ?
Do the blood vessels appear to be
very near the surface of the gills, or
away from the surface? What advan-
tage in this? Are the gills smooth
or wrinkled? (Fig. 215.) What ad-
vantage? The bony supports of the

FIG. 215.— CARP, with
gills, called the gill arches, are shown right gill cover removed

to show gills.

in Fig. 216 (2, to &,). How many
arches on each side? The gill arches have projections
on their front sides, called gill rakers, to prevent food
from being washed
through the clefts
between the arches.
The fringes on the
rear sof “thes cull
arches are called
the gill filaments (a,
Pic e206)) 7) ihese
filaments support
the thin and much-
wrinkled borders of
the sills) forthe
gills are constructed
on the plan of exposing the greatest possible surface to

FIG. 216.— SKELETON AROUND THROAT OF FISH.

the water. Compare the plan of the gills and that of the
human lungs. The gill opening on each side is guarded by
seven rays (#4, Fig. 216) along the hinder border of the

116 BEGINNERS’ ZOOLOGY

gill cover. These rays grow from the tongue bone. (Zu,
Fig. 216. This is a rear view.)

Watch a live fish and determine how the water is forced
between the gills. Is the mouth opened and closed in the
act of breathing? Are the openings behind

(| :
is the gill covers opened and closed? How
Fa

Riese

gy LEE
tS

Ane

FIG. 218.— NOSTRILS, MOUTH, AND GILL OPENINGS OF
STING-RAY.

many times per minute does fresh water reach

FIG. 217. — ? ;
Crrcutation the gills? Do the mouth and the gill covers

IN GILLS. open at the same time ? Why must the water

in contact with the gills be changed constantly? Why
does a fish usually rest with its

head up stream? How may a Q ® roves,

fish be kept alive for a time —-

after it is removed from the at

water? Why does drying of Fic. 219. — GILL OPENINGS OF
the gills prevent breathing? If nae

the mouth of a fish were propped open, and the fish re-
turned to the water, would it suffocate? Why, or why not?

Food Tube. — The gullet is short and wide. The stomach is
elongated (Fig. 220). There is a slight constriction, or narrow-
ing, where it joins the intestine. Is the intestine straight, or does
it lie in few or in many loops? (Fig. 220.) The liver has a gall
bladder and empties into the intestine through a bile duct. Is the

FISHES 117

liver large or small? Simple orlobed? The spleen (m7, Fig. 220)
lies in a loop of the intestine. ‘The last part of the intestine is
straight and is called the rectum. Is it of the same size as the
other portions of the intestine? The fish does not possess a pan-
creas, the most important digestive gland of higher vertebrates.

Fox

ii al
ceo =

4 IS

S
SJ

ma

FIG. 220.— ANATOMY OF CARP. (See also coloured figure 4.)

4f, barbels on head (for feeling); %, ventricle of heart; a@s, aortic bulb for regulating flow to .
gills; v%, venous sinus; ao, dorsal aorta; 7a, stomach; J, liver; gé, gall cyst; 272, spleen;
d, small intestine; »d, large intestine; @, vent; s,s, swim bladder; x7, 22, kidney; 42,
ureter; 44, bladder; 70, eggs (roe); ze, opening of ducts from kidney and ovary.

Questions: Are the kidneys dorsal or ventral? Theswim bladder? Why ? Why is the
swim bladder double? Does blood enter gills above or below ?

The ovary lies between the intestine and the air bladder. In Fig.
220 it is shown enlarged and filled with egg masses called roe. It
opens by a pore behind the vent. The silver lining of the body cavity
is called the peritoneum.

Is the air bladder in the perch simple or partly divided? In the
carp? (Fig.220.) Is it above or below the centre of the body? Why?
The air bladder makes the body of the fish about as light as water
that it may rise and sink with little effort. When a fish dies, the gases
of decomposition distend the bladder and the abdomen, and the fish
turns over. Why?

Where are the £7dneys? (Fig. 220.) Their ends unite close under
the spinal column. The ureters, or tubes, leading from them, unite.
and after passing a small urinary bladder, lead to a tiny urinary pore
just behind the opening from the ovary. (Coloured figure 4.)

The Circulation. — The fish, unlike other vertebrates, has its
breathing organs and its heart in its head. The gills have already
been described. The heart of an air-breathing vertebrate is near

118 BEGINNERS’ ZOOLOGY

its lungs. Why? The /eart of a fish is near its gills for the same
reason. ‘The heart has one auricle and one ventricle. (Coloured
figure 1.)

Blood returning to the heart comes through several veins into a
sinus, Or antechamber, whence it passes down through a valve

FIG, 221.— PLAN OF CIRCULATION.

Ad, arteries to gills; Ba, aortic bulb; V, ventricle.

into the au7tcle ; from the auricle it goes forward into the ventricle.
The ventricle sends it into an a7¢ery, not directly, but through a
bulb (as, Fig. 220), which serves to maintain
a steady flow, without pulse beats, into the
large artery (aorta) leading to the gills. The
arteries leading from the gills join to form a
dorsal aorta (Ao, Fig. 221), which passes
backward, inclosed by the lower processes of
the spinal column. After going through the
capillaries of the various organs, the blood
returns to the heart through veins.

The colour of the blood is given by red
corpuscles. ‘These are nucleated, oval, and
larger than the blood corpuscles of other ver-
tebrates. The blood of the fish is slightly

Fic. 222.—Brain or above the temperature of the water it in-
PERCH, from above. habits.

m,end of nerve of smell; Notice the general shape of the brain
au, eye; v, 2, m, fore, : ‘ a toes Le
mid, and hind brain. (Fig. 222). Are its subdivisions distinct or
h, spinal bulb; 7, spi- indistinct? Are the lobes in pairs? The
al cord. Po :
ae middle portion of the brain is the widest,
and consists of the two offic Jobes. From these lobes the optic

nerves pass beneath the brain to the eyes (.S”, Fig. 223). In

FISHES 119

front of the optic lobes lie the two cerebral lobes, or the cerebrum.
The small odfactory dobes are seen (Fig. 224) in front of the cere-

brum. The olfactory nerves may be traced to the nostrils. Behind
the optic lobes (mid brain) is the cerebellum (hind brain) and
behind it is the medulla oblongata

or beginning of the spinal cord.

SSS
SSS

FIG. 223.— BRAIN OF PERCH, FIG. 224. BRAIN OF PERCH,
side view. from above.

If you take the eyeball for comparison, is the whole brain as large
as one eyeball? (Fig. 222.) If you judge from the size of the parts of

the brain, which is more important with the fish, thinking or per-
ception? Which is the most important sense?

The scales along a certain line on each side of the fish, called
the lateral line, are perforated over a series of lateral line sense
organs, supposed to be the chief organs of ¢ouch (see Fig. 209).

Questions. — Which of the fins of the fish have a use
which corresponds to the keel of a boat? The rudder? A

FIG. 225.— THE STICKLEBACK. Instead of depositing the eggs on
the bottom, it makes a nest of water plants — the only fish that does
so —and bravely defends it,

120 BEGINNERS’ ZOOLOGY

paddle for sculling?
An oar? State several .
reasons why the head
of the fish must be
very large, although
the brain is very small.
Does all the blood go
to the gills just after
leaving the heart ?
Make a list of the
different species of

FIG. 226.— ARTIFICIAL FECUNDATION. The 3
egg-cells and sperm-cells are pressed out into fish found in the

eee waters of your neigh-
bourhood; in the markets of your town.

Reproduction.— The female fish deposits the unfertilized
eggs, or ova, in a secluded spot on the bottom. Afterward
the male fish deposits the sperms in the same place (see
Fig. 225). The eggs, thus unprotected, and newly hatched
fish as well, are used for food by fish of the same and other
species. To compensate for this great destruction, most
fish lay (spawn) many thousands of eggs, very few of
which reach maturity. Higher vertebrates (e.g. birds) have,
by their superior in-
telligence, risen above
this wasteful method
of reproduction. Some
kinds of marine fish,

ine
notably cod, herring, FIG. 227.— NEWLY HATCHED TROUT, with

and salmon, go many yolk-sac adhering, eyes large, and fins mere
miles up fresh rivers folds of the skin. (Enlarged.)

to spawn. It is possible that this is because they were
originally fresh-water species; yet they die if placed in

fresh water except during the spawning season. They go

FISHES 12!

because of zxzstinct, which is simply an inherited habit.
Rivers may be safer than the ocean for their young. They
are worn and exhausted by the journey, and never survive
to lay eggs the second time.

FIG. 228.—A SHARK (Acanthias vulgaris).

The atr bladder is developed from the food tube in the
embryo fish, and is homologous with lungs in the higher
vertebrates. Are their functions the same ?

Fish that feed on flesh have a short intestine. Those
that eat plants have a long intestine. Which kind of food
is more quickly digested ?

There are mucous glands in the skin of a fish which
supply a secretion to facilitate movement through the
water ; hence a freshly caught fish, before the secretion
has dried, feels very slippery.

The air bladder, although homologous to lungs, is not a
breathing organ in common fishes. It is filled by the
formation of gases from the blood, and can sbe made
smaller by the contraction of muscles along the sides of
the body; this causes the fish to sink. In the gar and
other ganoids, the air bladder contains blood vessels, is con-
nected with the gullet, and is used in breathing. Organs
serving the same purpose in different animals are said to be
analogous. To what in man are the gills of the fish analo-
gous? Organs having a “ike position and origin are
said to be homologous. The air bladders of a fish are
homologous witn the lungs of man; but since they have
not the same use they are not analogous.

122 BEGINNERS’ ZOOLOGY

How does the tail of a shark or a gar differ from the
tail of common fishes? (Fig. 228.) Do you know of fish
destitute of scales? Do you know of fish with whiplike
feelers on the head? (Figs.) Why are most fishes white
on the under side?

Comparative Review. — (Copy table on one page or two facing pages
of notebook.)

Is THERE DIGESTIVE
METHOD OF REPRODUC-
A Heap? ORGANS AND
z FEEDING TION
A NEcK? DIGESTION

SENSES

Ameceba _

Sponge

Hydra

Starfish

Earthworm

Wasp

Mussel

Fish

FI1G. 229. — DRAWING THE SEINE,

FIG. 234. — TURBOT. FIG. 239. SALMON.

Seven Food Fish. Three Curious Fish.
SPECIAL REPORTS. (Encyclopedia, texts, dictionary.)

123

(Hippocampus),
with incubat-
ing pouch, 74.

FIG. 244.— LUNG FIsH of Australia
(Ceratodus miolepis).

FIG. 242.— TCRPEDO. Elec-
trical organs at right and FIG. 246,—SEAWEED FISH. x}
left of brain. (Phyllopteryx eques).

Remarkable Fish. SPECIAL REPORTS. (Encyclopedia, texts, dictionary.)
124

GENERAL CLASSIFICATION 125

RECOGNITION GROUP CHARACTERS

The commoner members of the several branches may be recog-
nized by the following characters : —

1. The Protozoans are the only one-celled animals.

2. The Sponges are the only animals having pores all over the
body for the inflow of water.

3. The Polyps are the only many-celled animals having a single
opening into the body, serving for both mouth and vent. They
are radiate in structure, and usually possess tentacles.

4. The Echinoderms are marine animals of more or less radiate
appearance, having a food tube in the body separate from the
body wall.

The following groups are plainly bilateral: that is, dorsal and
ventral surfaces, front and hind ends are different.

5. The Vermes have usually a segmented body but lack jointed
legs.

6. The Arthropods! have an external skeleton and jointed legs.

7. The Molluscs have soft bodies, no legs, no skeleton, but
usually a limy shell.

8. The Vertebrates have an internal skeleton of bones, and
usually two pairs of legs.

1 Insects and crustaceans.

FIG. 247.—A SNAIL. (Which
branch? Why?)

CHAPTER XI
BATRACHIA

Tue theory ot evolution teaches that animal life began in a very
simple form in the sea, and that afterward the higher sea animals
lost their gills and developed lungs and legs and came out to live
upon the land; truly a marvellous procedure, and incredible to
many, although the process is repeated every spring in count-
less instances in pond and brook.

In popular language, every cold-blooded vertebrate breathing
with lungs is called a reptile. The name reptile is properly
applied only to lizards, snakes, turtles, and alligators. The com-
mon mistake of speaking of frogs and salamanders as reptiles —
arises from considering them only in their adult condition. Rep-
tiles hatch from the egg as tiny reptiles resembling the adult
forms ; frogs and salamanders, as every one knows, leave the egg
in the form of tadpoles (Fig. 248). The fact that frogs and
salamanders begin active life as fishes, breathing by gills, serves to
distinguish them from other cold-blooded animals, and causes
naturalists to place them in a separate class, called batrachia
(twice breather) or amphibia (double life).

TADPOLES

SucceEstions. -—- Tadpoles may be studied by placing a number
of frog’s eggs in .a jar of water, care being taken not to place
a large number of eggs in a small amount of water. When they
hatch, water plants (¢.g. green algze) should be added for food.
The behaviour of frogs may be best studied in a tub of water. A
toad in captivity should be given a cool, moist place, and fed well.
A piece of meat placed near a toad may attract flies, and the toad
may be observed while catching them, but the motion is so swift
as to be almost imperceptible. Live flies may be put into a glass
jar with a toad. Toads do not move about until twilight, except

126

BATRACHIA 127

in cloudy, wet weather. They return to ponds and brooks in
spring at the time for laying eggs. ‘This time for both frogs and
toads is. shown by trilling. All frogs, except tree frogs, remain in
. or near the water all the year.

s .
FIG. 248.— METAMORPHOSES OF THE FROG, numbered in order.

Do eggs hatch and tadpoles grow more rapidly in a
jar of water kept in a warm place or in a cold placer
In pond water or in drinking water? Can the tadpoles be
seen to move in the eggs before hatching? When do
the external gills show? (Fig. 248.)

What parts may be described in a tadpole? What is
the shape of the tail? Compare the tadpole with the fish
as to (1) general
shape, (2) cover-
ing, (3) fins, (4)
tail, (5) gills.

Do the exter-
nal gills disap-
pear before or after any rudiments of limbs appear?
(6, 7, Fig. 248.) Can you locate the gills after they be-
come internal? (Fig. 249.)

FIG. 249. — TADPOLE, from below, showing intestine
and internal gills. (Enlarged.)

128 BEGINNERS’ ZOOLOGY

In what state of growth are the /egs when the tadpole
first goes to the surface to breathe? Which legs appear
first? Of what advantage is this? What becomes of the
tail? Is the tail entirely gone before the frog first leaves
the water? Are tadpoles habitually in motion or at
rest ?

Is the intestine visible through the skin? (Fig. 249.)
Is it straight or coiled? Remembering why some fish
have larger intestines than others, and that a cow has a
long intestine and a cat a short one, state why a tad-
pole has a relatively longer intestine than a frog.

Compare the mouth, jaws, eyes, skin, body, and habits
of zadpole and frog.

FrRrocGs

Prove that frogs and toads are beneficial to man. Did
you ever know of a frog or a toad destroying anything
useful, or harming any one, or causing warts? How
many pupils in class ever had warts? Had they handled
frogs before the warts came? Frogs are interesting,
gentle, timid animals. Why are they repulsive to some
people?

Environment.—Where are frogs found in greatest
numbers? What occurs when danger threatens them?
What enemies do they have? What colour, or tint, is most
prominent on a frog? Does the colour ‘“mimic’’ or amt-
tate its surroundings? What is the colour of the under
side of the body? (Fig. 250.) Why is there greater
safety in that colour? What enemies would see water frogs
from below? Do tree frogs mimic the bark? The
leaves?

Can a frog stay under water for an indefinite time?
Why, or why not? What part of a frog is above the

BATRACHIA 129

surface when it floats or swims in a tub of water? Why?
Do frogs croak in the water or on the bank? Why do
they croak after a rain? Do toads croak?

Are the eggs laid in still or in flowing water? In a clear
place or among sticks and stems? Singly, or in strings or
in masses? (Fig. 248.) Describe an egg. Why do frogs
dig into the mud in autumn in cold climates? Why do
they not dig in mud at the bottom of a pond?

FIG. 250.— PAINTED FROG (Chorophilus ornatus), of Mexico.

Describe the position of the frog when still (Fig. 250).
Of what advantage in this position? Does the frog use
_its fore legs in swimming or jumping? Its hind legs?
How is the frog fitted for jumping? Compare it in this
respect with a jumping insect; a jumping mammal. How
is it fitted for swimming? Is the general build of its body
better fitted for swimming or for jumping? How far can a
frog jump? |

External Features. — The frog may be said to have two
regions in its body, the head and the trunk. A neck hardly

130 BEGINNERS’ ZOOLOGY

exists, as there is only one vertebra in front of the shoul-
ders (Fig. 252), while mammals have seven neck (cervical)
vertebrae. There are no tail (caudal) vetieDia even in the
tadpole state of frogs and toads.

The ead appears triangular in shape when viewed from
what direction? The head of a frog is more pointed than
the head of a toad. Is the skull a closed case of broad
bones or an open structure of narrow bones? (Fig. 252.)

Describe the mouth. Observe the extent of the mouth
opening (Fig. 251). Are teeth present in the upper jaw?
The lower jaw? Are the teeth sharp or dull? Does the
frog chew its food? Is the Zongue
slender or thick? (Fig. 251.) Is
it attached to the front or the back
of the mouth? In what direction
does the free end extend when the
tongue lies flat? Is the end pointed
or lobed? How far out will the
tongue stretch’ For what is it
used? Why is it better for the teeth to be in the upper
jaw rather than in the lower jaw? ‘That the teeth are of
little service is shown by the fact that the toad with simi-
lar habits of eating has no teeth. Will a toad catch and

FIG. 251.— HEAD OF FROG.

swallow a bullet or a pebble rolled before it? The toad is
accustomed to living food, hence it prefers a moving
insect to a still one.

The Senses. —Compare the eyes with the eyes of a
fish in respect to position and parts. Are the eyes pro-
truding or deep-set? Touch the eye of a live frog. Can
it be retracted ? What is the shape of the pupil? The
colour of the iris? Is the eye bright or dull? What prob-
ably gave rise to the superstition that a toad had a
jewel in its head? Is there a third eyelid? Are the

BATRACHIA 131

upper and lower eyelids of the same thickness ?. With
which lid does it wink? Close its eye?

Observe the large oval car drum or tympanum. What
is its direction from the eye? (Fig. 251.) The mouth?
Is there a projecting ear? Does the frog hear well?
What reason for your answer? As in the human ear, a
tube (the Eustachian tube) leads from the mouth to the
inner side of the tympanum.

How many zostrils? (Fig. 251.) Are they near to-
gether or separated? Large or small? A bristle passed
into the nostril comes into the mouth not far back in the
roof. Why must it differ from a fish in this?

How do the fore and hind legs differ? How many toes
on the fore foot or hand? On the hind foot? On which
foot is one of the toesrudimentary ? Why is the fore limb
of no assistance in propelling the body in jumping? Do
the toes turn in or out? (Fig. 250.) How does the frog
give direction to the
jump? What woul
be the disadvantage
of always jumping
straight forward
when fleeing? Which
legs are more useful
in alighting ?

Divisions of the
Limbs. — Distinguish
the upper arm, fore-
arm, and hand in the
fore limb (Figs. 252 and 253). Compare with skeleton of
man (Fig. 399). Do the arms of a man and a frog both
have one bone in the upper arm and two in the forearm ?
Both have several closely joined bones in the wrzst and

FIG. 252.— SKELETON OF FROG,

132 BEGINNERS’ ZOOLOGY

five separate bones in the fa/m. Do any of the frog’s
fingers have three joints? Compare also the leg of man
and the hind leg
of the frog (Figs.
253 and 399). Does
the ¢hzgh have one
bone in each? The
shank of man has
two bones, shin and
splint bone. Do
you see a groove
near the end in the
shank bone of a
frog (Fig. 252), in-
dicating that it
was formed by the

union of a shin and

FIG. 253.— SKELETON OF FROG,

a splint bone? The
first two of the five bones of the ankle are elongated, giv-
ing the hind leg the appearance of
having an extra joint (Fig. 253). The
foot consists of six digits, one of which,
like the thumb on the fore limb, is
rudimentary. The five developed toes
give the five digits of the typical verte-
brate foot. ' Besides the five bones cor-
responding to the instep, the toes have
two, three, or four bones each. How
is the hind foot specialized for swim- Fic. 254.— Lec Mus-
ming? Which joint of the leg con- SS SE ee
tains most muscle? (Fig. 254.) Find other bones of the
frog analogous in position and similar in form to bones in
the human skeleton.

BATRACHIA 133

Is the skin of a frog tight or loose? Does it have any
appendages corresponding to scales, feathers, or hair of
other vertebrates? Is the skin rough or smooth? The
toad is furnished with glands in the skin which are some-
times swollen; they form a bitter secretion, and may be,
to some extent, a protection. Yet birds and snakes do not
hesitate to swallow toads whole. Show how both upper
and under surfaces of frog illustrate protective colouration.

All batrachians have large and zzmerous blood vessels
a the skin by which gases are exchanged with the air,
the skin being almost equal to a third lung. That the
skin may function in this way, it
must not become dry. Using this
fact, account for certain. habits of
toads as well as frogs.

If a frog is kept in the dark or
on a dark surface, z¢s skin will be-
come darker than if kept in the light
or on a white dish. Try this experi-
ment, comparing two frogs. This
power of changing colour is believed
to be due to the diminution in size
of certain pigment cells by contrac-
tion, andenlargement fromrelaxation.
This power is possessed to a certain
degree not only by batrachians but
also by many fishes and reptiles.

FIG. 255.— DIGESTIVE
CANAL OF FROG.

Mh, mouth; Z, tongue pulled
outward; S, opening to
larynx; Oe, gullet; 17, stom-

The chameleon, or green lizard,
surpasses all other animals in this
respect (Fig. 280). What advan-
tage from this power?

ach; D, intestine; PP, pan-
creas; JZ, liver; G, gall
bladder; F, rectum; Hé,
bladder; C7, cloaca; A,
vent,

Digestive System. — The large mouth cavity is connected
by a short throat with the gullet, or cesophagus (Fig. 255). ~

134 BEGINNERS’ ZOOLOGY

A slit called the glottis opens from the throat into the
lungs (Fig. 255). Is the gullet long or short? Broad
or narrow? Is the stomach short or elongated? Is the
division distinct between stomach and gullet, and
stomach and intestine? Is the liver large or small? Is
it simple or lobed? The pancreas lies between the
stomach and the first bend of the intestines (Fig. 255).
What is its shape? A bile duct connects the liver with

the small intestine (De, Fig.
255). It passes through the
pancreas, from which it re-
ceives several pancreatic
ducts. After many turns, the
small intestine joins the large
intestine. The last part of
the large intestine is called
the rectum (Latin, straight).
The last part of the rectum is
called the cloaca (Latin, a
drain), and into it the ducts

FIG. 256.— ANATOMY OF SALA- from the kidneys and the re-
MANDER. productive glands also open.
7a, heart; 2,lungs; 3a, stomach; 34,in- The kidneys are large, elon-
testine; 3c, large intestine; ¢, liver; N
8, egg masses; 70, bladder; 7, vent. gated, and flat. They lieun-
der the dorsal wall. The urinary bladder is also large. Does
the salamander havea similar digestive system? (Fig. 256)
Why are the liver and the lungs (Fig. 256) longer in a
salamander than in a frog?

Respiration. — How many /umgs? Are they simple
or lobed? (Fig. 256.) A lung cut open is seen to be
baglike, with numerous ridges on its inner surface.
This increases the surface with which the air may come

in contact. In the walls of the lungs are numerous

BATRACHIA 135

capillaries. Does the frog breathe with mouth open or
closed? Does the frog have any ribs for expanding the
chest? What part of the head expands and contracts?
Is this motion repeated at a slow or a rapid rate? Regu-
larly or irregularly? There are valves in the nostrils for
opening and closing them. Is there any indication of
opening and closing as the throat expands and contracts ?
The mouth and throat (pharynx) are filled with air each
time the throat swells, and the exchange of gases (which
gases?) takes place continually through their walls and
the walls of the lungs. At intervals the air is forced
through the glottis into the lungs. After a short time
it is expelled from the lungs by the muscular abdominal
walls, which press upon -the abdominal organs, and so
upon the lungs. Immediately the air is forced back
into the lungs, so that they are kept filled. In some
species the lungs regularly expand at every second con-
traction of the throat. This is shown by a slight out-
ward motion at the sides. Does the motion of the throat
cease when the frog is under water? Why would the
frog be unable to breathe (except through the skin) if its
mouth were propped open? Why does the fact that the
breathing is so slow as almost to cease during hibernation,
aid the frog in going through the winter without
starving ? (Chap. I.) Why must frogs and toads keep their
skins moist? Which looks more like a clod? Why?

The Heart and Circulation. — What is the shape of the heart?
(Fig. 257.) Observe the two auricJes in front and the conical
ventricle behind them. The great arterial trunk from the ventricle
passes forward beyond the auricles; it divides into two branches
which turn to the right and the left (Fig. 257). Each branch im-
mediately subdivides into three arteries (Fig. 257), one going to
the head, one to the lungs and skin, and a third, the largest,

136 BEGINNERS’ ZOOLOGY

passes backward in the trunk, where it is united again to its
fellow.

Both the pulmonary veins, returning to the heart with pure
blood from the lungs, empty into the left auricle. Veins with the
impure blood from the body empty into the right auricle. Both
the auricles empty into the ventri-
cles, but the pure and the impure
blood are prevented from thoroughly
mixing by ridges on the inside of the
ventricle. Only in an animal with
a four-chambered heart does pure
blood from the lungs pass unmixed
and pure to ail parts of the body,

FIG. 257. PLAN OF FROG’S
CIRCULATION.

Venous system is black; the arterial,
white, AU, auricles; V’, ventricle;
L,lung; Z/V, liver. Aortahasone FIG. 258.—FROG’S BLOOD (magnified 2500
branch to right, another to left, which areas). Red cells oval, nucleated, and
reunite below. Right branch only
persists in birds, left branch in beasts
and man.

larger than human blood cells. Nuclei of
two white cells visible near centre. (Pea-
body.)
and only such animals are warm-blooded. The purer (¢.e. the more
oxygenated) the blood, the greater the oxidation and warmth.
The red corpuscles in a frog’s 4/ood are oval and larger than those
of man. Areallof them nucleated? (Fig. 258.) The flow of d/ood in
the web of a frog’s foot is a striking and interesting sight. It may
be easily shown by wrapping a small frog in a wet cloth and laying

it with one foot extended upon a glass slip on the stage of a
miscroscope.

BATRACHIA 137

The brain of the frog (Fig. 259) is much like that of a fish
(Fig. 224). The olfactory, cerebral, and optic lobes, cerebellum
and medulla are in the same relative position, although their rela-
tive sizes are not the same. Compared with the
other parts, are the
olfactory lobes more
or less developed
than in a fish? The
cerebral hemispheres ?
The optic lobes? The
cerebellum? There is
a cavity in the brain.
It is readily exposed
on the under surface
of the medulla by cut-
ting the membrane,
which is theré its only

FIG. 260. — NERVOUS SYSTEM

FIG. 259. — :
PeatosEnoc. coverne (Fig. 250). OF FROG.

Frogs and toads are beneficial (why ?) and do not the slight-
est injury to any interest of man. If toads are encouraged
to take up their abode in a garden, they will aid in ridding
it of insects. A house may be made in a shady corner with
four bricks, or better still, a hole a foot deep may be dug to
furnish them protection from
the heat of the day. A toad’s & 9) JU
muzzle is not so tapering as a
frog’s (why ?), its feet are not |
so fully webbed (why?), and its
skin is not so smooth (why ?).

In case of doubt, open the

mouthand rub the finger along Fic. 261.— Position of legs in tail-
the upper jaw a frog has sharp less (A) and tailed (6) amphibian.
teeth, a toad none at all. The tadpoles of frogs, toads, and
salamanders are much alike. In toad’s spawn the eggs lie in
strings inclosed in jelly; frogs spawn is in masses (Fig. 248).

aay me >

A B

138 BEGINNERS’ ZOOLOGY

Any batrachian may easily be passed around the class after placing
it in a tumbler with gauze or net tied over top. It should be kept in a
box with two inches of moist earth on the bottom. If no live insects
are obtainable for feeding a toad, bits of moist meat may be dangled
from the end of a string. If tadpoles are placed ina pootoratubina
garden, the toads hatched will soon make destructive garden insects
become a rarity.

Does a frog or a salamander have the more primitive
form of body? Why do you think so? Salamanders are
sometimes called mud puppies. The absurd belief that
salamanders are poisonous is to be classed with the belief
that toads cause warts. The belief among the ancients
that salamanders ate fire arose perhaps from seeing them
coming away from fires that had been built over their
holes on river banks by travellers. Their moist skin pro-
tected them until the fire became very hot.

Describe the ‘‘mud puppy” shown in Fig. 262. The:
pouched gopher, or rat (Fig. 371), is sometimes absurdly
called a salamander.

FIG. 262.— BLIND SALAMANDER (Proteus anguinus). x}. Found in caves and
underground streams in Balkans. Gills external, tail finlike, legs small.

CHAPTER) Xtt
REPTILIA (REPTILES)

Tus class is divided into four orders which have such
marked differences of external form that there is no diffi-
culty in distinguishing them. These orders are represented
by Lizards, Snakes, Turiles,and Alligators. Of these, only
the forms of lizards and alligators have similar propor-
tions, but there is a marked difference in their size,
lizards being, in general, the smallest, and alligators the
largest of the reptiles.

Comparison of Lizards and Salamanders. — To make clear
the difference between reptiles and batrachians, it will be
well to compare the orders in the two classes which re-
semble each other in size and shape; namely, lizards and

FIG. 263. — A SALAMANDER. : FIG. 264.— A LIZARD.

salamanders (Figs. 263 and 264). State in a tabular form
their differences in s&zz, toe, manner of breathing, develop-
ment from egg, shape of tail, habitat, habits. Each has
an elongated body, two pairs of limbs, and a long tail, yet
they are easily distinguished. Are the differences sug-
gested above valid for the other batrachians (frogs) and
other reptiles (¢.g. turtles)? Trace the same differences
139

140 BEGINNERS’ ZOOLOGY

between the toad or frog (Fig. 250) and the “horned
toad,’ which is a lizard (Fig. 265).

Fic. 265.—‘“ HORNED TOAD” LIZARD, of the Southwest
(Phrynosoma cornita). x3,

STUDY OF A TURTLE OR A TORTOISE

SuGcEsTions. — Because of the ease with which a tortoise or
a turtle may be caught and their movements and habits studied, it is
suggested that one of these be studied as an example of reptiles.
Besides a live specimen, a skeleton of one species and the shells of
several species should be available.

A

ag ——s
YE aR :

FIG. 266.— EUROPEAN POND TURTLE (mys lutaria). (After Brehms.)

The body (of a turtle or a tortoise) is divided distinctly
into regions (Fig. 266). Is there a head? Neck? Trunk?
Tail? The trunk is inclosed by the so-called shell, which

REPTILIA 141

consists of an upper portion, the carapace, and a lowet
portion, the p/astron. How are the other regions covered ?
What is the shape of the head? Is the mouth at the
front, or on the under side? Where are the zostrzls ?
Are the motions of breathing visible? Is there a beak or
snout? Do the jaws contain /eeth ?

Do the eyes project? Which is thinner and more
movable, the upper ox the lower lid? Identify the third eye-
lid (sictitating membrane). It is translucent and comes
from, and is drawn into, the inner corner of the eye. It
cleanses the eyeball. Frogs and birds have a similar
membrane. The circular ear drum is ina depression back
of the angle of the mouth. What other animal studied
has an external ear drum ?

The tortoise has a longer, more flexible neck than any
other reptile. Why does it have the greatest need for
such a neck? Is the skin over the neck tight or loose?
Why?

Do the legs have the three joints or parts found on the
limbs of most vertebrates? How is the skin of the legs
covered? Do the toes have claws? Compare the front
and the hind feet. Does the tortoise slide its body orlift it
when walking on hard ground? Lay the animal on its
back on a chair or a table at one side of the room in view
of the class. Watch its attempts to right itself. Are
the motions suited to accomplish the object? Does the
tortoise succeed ?

What are the prevailing colours of turtles? How does
their colouration correspond to their surroundings?

What parts of the tortoise extend at times beyond the
shell? Are any of these parts visible when the shell zs
closed? ‘What movements of the shell take place as it is
closed? Is the carapace rigid throughout? Is the plastron?

142 BEGINNERS’ ZOOLOGY

The Skeleton (Fig. 267). — The carapace is covered with

thin epidermal plates which belong to the skin. The bony

nature of the carapace is
seen when the plates are
removed, or if its inner
surface is viewed (Fig.
267). It is seen to con-
sist largely of wide 7zds
(how many?) much flat-
tened and grown together
at their edges. The ribs
are seen to be rigidly at-
tached to the vertebre.
The rear projections of
the vertebrz are flattened
into a series of bony plates
which take the place of
the sharp ridge found
‘along the backs of most

vertebrates.

FIG. 267. —SKELETON OF EUROPEAN
TORTOISE.

C, rib plates; 17, marginal plates; B, plastron;
H, humerus bone; &, radius; U, ulna;
Fe, femur.

Show that the shell

FIc. 268.— THREE-CHAM-
BERED HEART OF A REp-
TILE (tortoise).

a, veins; 4, f, right and left auri-
cles; cg, ventricle; d, arteries to
lungs; ¢, veins from lungs; z, 2,
two branches of aorta. Compare

with Fig. 269 and coloured Fig.2.

of a turtle is not homologous with
the shells of mollusks. Does the
turtle have shoulder blades and
collar bones? Hip bones? Thigh
bones? Shin bone (fibia) and splint
bone (fibula)? (Fig. 267.)

Do the plates formed by the ribs
extend to the edge of the cara-
pace? See Fig. 267. About how
many bony plates form the cara-
pace? The plastron? Do the
horny plates outside correspond
to the bony plates of the shell?

REPTILIA

143

How many axial plates?) How many costal (rib) plates?
How many border plates? Which plates are largest?

Smallest? Do the horny plates
overlap like shingles, or meet edge
to edge? Is there any mark where
they meet on the bony shell?
Basing it upon foregoing facts,
give a connected and complete de-
scription of the structure of the
carapace. Compare the skeleton
of the turtle with that of the snake,
and correlate the differences in
structure with differences in habits.

Draw the tortoise seen from the

5.
A
A
S

FIG. 269.— PLAN OF REP-
TILIAN CIRCULATION,
_ See arrows.

side or above, with its shell closed, showing the arrangé-

ment of the plates.
Place soft or tender vegetable

FIG. 270.— REPTILIAN VIS-
CERA (lizard).
tv, windpipe; /, heart; Zz, lungs;
dr, liver; ma, stomach; dd,
md, intestines; 44, bladder.

food, lettuce, mushroom, roots, ber-
ries, and water, also meat, in reach
of the turtle. What does it pre-
fer? How does it eat? It has no
lips; how does it drink ?

Study the movements of its eye-
balls and eyelids, and the respira-
tory and other movements .already
mentioned. State a reason for
thinking that no species of land
animals exists that lacks the sim-
ple power of righting itself when
turned on its back.

Tortoise, Turtle, Terrapin. — The
turtles belong to the order of rep-
tiles called chelonians. No one

144 BEGINNERS’ ZOOLOGY

can have any difficulty in knowing a member of this order.
The subdivision of the order into families is not so easy,
however, and the popular attempts to classify chelonians
as turtles, tortoises, and terrapins have not been entirely
successful. Species with a vaulted shell and imperfectly
webbed toes and strictly terrestrial habits are called /or-
toises. Species with flattened shells and strictly aquatic
habits should be called ¢evrapins (e.g. mud terrapin). They
have three instead of two joints in the middle toe of each
foot. The term ¢u7tle may be applied to species which are
partly terrestrial and partly aquatic (e.g. snapping turtle
(Fig. 271)). Usage, however, is by no means uniform.

x pe ASV! WN USYES fi yh?
15" Aer, - : i. NW pA if \

Fee

i

x

(
\
nN

FIG. 271.—SNAPPING TURTLE (Chelydra serpentina).

Most reptiles eat animal food ; green terrapins and some
land tortoises eat vegetable food. Would you judge that
carnivorous chelonians catch very active prey ?

The fierce sxapping turtle, found in ponds and streams,
sometimes has a body three feet.long. Its head and tail
are very large and cannot be withdrawn into the shell.
It is carnivorous and has great strength of jaw. It has
been known to snap a large stick in two. The dor tortozse
is yellowish brown with blotches of yellow, and like its
close kinsman, the pond turtle of Europe (Fig. 266), with-
draws itself and closes its shell completely. Both lids of the
plastron are movable, a peculiarity belonging to these two
species. The giant tortoise of the Galapagos Islands, ac-

REPTILIA

145

cording to Lyddeker, can trot cheerfully along with three
full-grown men on its back. “ Tortoise shell” used for
combs and other articles is obtained from the overlapping
scales of the awkdzll turtle, common in the West Indies.
The diamond-back terrapin, found along the Atlantic Coast
from Massachusetts to Texas, is prized for making soup.

FIG. 272.— A RATTLESNAKE.

Venomous snakes named _ in
order of virulence: 1. Coral snakes,
Elaps, about seventeen red bands
bordered with yellow and black
(coloured figure 6) (fatal). 2.
Rattlesnakes (very deadly). 3.
Copperhead (may kill a small
animal of the size of a dog).
4, Water moccasin (never fatal).
5. Ground rattler.— Effects: Pulse
fast, breathing slow, blood tubes
dilated, blood becomes stored in ab-
dominal blood tubes, stupefaction

FIG. 273@a.—HEAD OF
VIPER, showing typical
triangular shape of head
of venomous snake.

FIG. 2734.—SIDE VIEW,
showing poison fangs ; also
tongue (forked, harmless).

FIG. 274.— VIPE®'S HEAD,
showing poison sac at
base of fangs.

FIG. 275.— SKULL, showing
teeth, fangs, and quadrate
bone to which lower jaw
is joined. See Fig. 284.

146 BEGINNERS’ ZOOLOGY

and death from blood being withdrawn from brain. Al
ways two punctures, the closer together the smaller the
snake. Remedies: Ligature between wound and heart,
lance wound and suck; inject into wound three drops of 1
per cent solution of chromic acid or potassium perman-
ganate. Give strychnine, hypodermically, until strychnine
symptoms (twitchings) appear. No one but a physician
should give strychnine. Digitalin or caffein acts like
strychnine; alcohol has opposite effect.

Protective Coloration and Mimicry.—When an animal
imitates the colour or form of its tvanimate surroundingsit
is said to be protectively
coloured or formed. Give
an instance of protective
Coloration or form a-
mong lizards; butterflies ;
grasshoppers; amp hi-
bians; echinoderms.
When an animal imitates the colour or the form of
another animal it is said to mzmzc the animal. Mimicry
usually enables an animal to deceive
enemies into mistaking it for an ani-
mal which for some reason they avoid.
The milkweed butterfly has a taste FIG. 277.—SKULL OF
that is repulsive to birds. The vice- meee Hai 7
roy butterfly is palatable to birds, but gity
it is left untouched because of its

FIG, 276. —“ GLASS SNAKE,” a lizard
without legs.

close resemblance to the repulsive
milkweed butterfly. The harlequin
snake (Zaps) of the Gulf states isthe Fic. 278. = SKULL oF
most deadly snake of North America milan
(Figs. 277, 278). It is very strikingly coloured with rings of
scarlet, yellow, and black. Thisisan example of warning
coloration. ‘Thescarlet snake (Lampropeltis) has bands of

COLOURED FIGURES I, 2, 3.—.CIRCULATION IN FISH, REPTILE, MAMMAL.

In which is blood from heart all impure ? Mixed? Both pure and impure?

FIG. 4.— ANATOMY OF CARP. For description see Fig. 220, page 117.

FIG. 5.— HARLEQUIN SNAKE (Zaps).

THE DEADLY
HARLEQUIN SNAKE
IS MIMICKED BY THE
HARMLESS SCARLET

SNAKE,

FIG. 6.—SCARLET SNAKE (Lamfpropeltis).

REPTILIA 147
scarlet, yellow, and black (coloured Fig.6) of the same tints,

and it is hardly distinguishable from the harlequin. The

ee
Se

FIG. 279.— GILA MONSTER (Heloderma suspectum), of Arizona. If poisonous, it
is the only instance among lizards. It is heavy-built, orange and black mottled,
and about 16 inches long. Compare it with the green lizard (Fig. 280).

scarlet snake is said to mzmic the harlequin snake. It also
imitates the quiet inoffensive hab- \ eo”
its of the harlequin snake, which
fortunately does not strike except
under the greatest provocation.
The rattles of the less poisonous
but deadly rattlesnake (Fig.
272) may be classed as an
example of warning sound which
most animals are quick to heed
and thus avoid encounters which
might be destructive to either the
snake or its enemy.

Survival of the Fittest. — The two
facts of most far-reaching importance
in the history of animals and plants ee ice Gannon eae
are: (1) Heredity; animals inherit lis), or green lizard of south-
the characteristics of their parents. ern U.S. Far excels European

(2) Variation; animals are not ex- chameleon (Fig. 281) and all

: : known animals in power of
actly like their parents. The first changing. colour (green, ‘gray;

fact gives stability, the second makes yellow, bronze, and black),

148 BEGINNERS’ ZOOLOGY

evolution possible. The climate of the world is slowly changing,
and animals must change to adapt themselves to it. A more
sudden change of environment (surroundings) of animals oc=
curs because of migration or isolation; these in turn are caused
by the crowding of
other animals or by
the formation or dis-
appearance of geo-
graphical barriers,
such as deserts, water,
mountain chains.

The young vary in
many ways from their
parents. Some have
a more _ protective
colour or form, sharper
claws, swifter movements, etc. The individuals possessing such bene-
ficial variations live longer and leave more offspring, and because
of heredity transmit the desirable qualities to
some of their young. Variations which are dis-
advantageous for getting food, defence, etc., cause
shorter life and fewer offspring. ‘Thus the “est
survive, the unfit perish; an automatic zatural
selection occurs.

Darwin taught that variations are infinitesimal
and gradual. Recent experiments and observa-
tions seem to show that many variations are by
sudden jumps, somewhat resembling so-called
“freaks of nature.’’ As to whether these “ sports,”
or individuals with new peculiarities, survive,
depends upon their fitness for their environ- pyc, 292, — EM-
ment. ‘Survival of the fittest’? results from this BRYO OF A
natural selection, but the selection occurs be- Raiser i
tween animals of marked, not infinitesimal, dif- (Challenger Re
ferences, as Darwin taught. Darwin’s theory is port.)
probably true for species in the usual state of nature; the new
theory (of De Vries) is probably true for animals and plants under
domestication and during rapid geographical changes.

FIG. 281. — CHAMELEON OF SOUTHERN EUROPE.

REPTILIA 149

Table for Review (for notebooks or blackboards).

| FisH TADPOLE FRroG | TURTLE LizARD

Limbs, kind and ; * | 7
number .

Are claws present ?
How many ?

Covering of body

Meethy ‘kinds Yof,= if
present

Which bones found
inmanare lacking?

Chambers of heart

Respiration |

Movements |

FIG. 283.—BIG-HEADED TURTLE (Platysternum megalocephalum). x}. China.
This and Fig. 282 suggest descent of turtles from a lizardlike form. Figure 282
shows earlier ancestors to have been gill breathers.

CHAP TER crt
BIRDS

SuccrEstions. — The domestic pigeon, the fowl, and the English
sparrow are most commonly within the reach of students. ‘The
last bird has become a pest and is almost the only bird whose
destruction is desirable. ‘The female is somewhat uniformly mot-
tled with gray and brown in fine markings. ‘The male has a black
throat with the other markings of black, brown, and white, in
stronger contrast than the marking of the female. As the different
species of birds are essentially alike in structural features, the direc-

‘tions and questions may be used with any bird at hand. When
studying feathers, one or more should be provided for each pupil
in the class. The feet and the bills of birds should be kept for study.

eee the pogy of the bird like the toad and the turtle,
: * havea head, a trunk, a tail, and two

_f* pairs of limbs? Do the fore and
hind limbs differ from each other more or
less than the limbs of other backboned
peice Does any other vertebrate use
them for purposes as widely different?

Eye. \ Does the eyeball have parts corresponding
to the eyeball of a fish or a frog; viz., cornea, iris, pupil?
Which is more movable, the upper or fhe lower eyelid? Are
there any lashes? The bird (like what other animal?) has
a third eyelid, or nictitating membrane. Compare its
thickness with that of the other lids. Is it drawn over
the eyeball from the inner or the outer corner of the eye?
Can you see in the human eye any wrinkle or growth
which might be regarded as remains, or vestige, of such a
membrane ?

150

BIRDS IDI

How many nostrils? In which mandible are they
located? Are they nearer the tip or the base of the
mandible? (Fig. 284.) Whatis theirshape? Do the nasal
passages go directly down through the mandible or do they
go backward? Is the inner nasal opening into the mouth
or into the throat ?.

The beak or bill consists of the upper and lower man-
dibles. The outside of the beak seems to be of what kind
of material? Examine the decapitated head of a fowl or of
a dissected bird, and find
if there is a covering on
the bill which can be cut
or scraped off. Is the
mass of the bill of bony
or horny material? With
what part of the human
head are the mandibles FIG. 284.—SKULL OF DOMESTIC FOWL.
homologous? (Fig. 284.) fiw is tached wo skull (wanting in beasts pres

Ears. — Do birds have ent in reptiles; see Fig. 277).
external ears? Is there an external opening leading to the
ear? In searching for it, blow or push forward the feath-
ers. If found, notice its location, size, shape, and what
surrounds the opening. There is an owl spoken of as the
long-eared owl. Are its ears long ?

The leg has three divisions: the uppermost is the chigh
(called the “second joint” in a fowl); the middle division
is the shank (or ‘“‘drumstick’’); and the lowest, which is
the slender bone covered with scales, is formed by the

union of the ankle and the instep. (The bones of the three
divisions are named femur, tibiotarsus, and tarsometa-

tarsus.) The foot consists entirely of toes, the bones of
which are called phalanges. Is there a bone in each claw?
(See Fig. 285.) Supply the numerals in this sentence:

152

The pigeon has toes, the

hind toe having
of the three front toes, the

joints ;

inner has

joints (count
the claw as one joint), the

Fic. 286.—SKELETON OF BIRD.

Rh, vertebre; C7, clavicle; Co, coracoid; Sc, scap-
ula; S#, sternum; A, humerus; A, radius; U,
ulna; P, thumb; Fe, femur; 7,tibia. See Fig. 394.
Questions: Which is the stiffest portion of the

vertebral column? How are the ribs braced against

each other? Which is longer, thigh bone or shin ?

Compare shoulder blade with man’s (Fig. 399). Which

is the extra shoulder bone? Compare tail vertebra

with those of extinct bird, Fig. 290.

feathered ?
ankle?

BEGINNERS’ ZOOLOGY

FIG. 285.— LEG BONES
OF BIRD.

middle has
and

joints, the

outer toe has
joints (Fig. 285).

Is the thigh of a bird bare or

The shin? The
Where is the ankle
Do
see the remains

joint of a bird?
you
of another bone (the
splint bone, or fibula)
on the shin bone of
the shank? (Fig. 285
or 286.) Why would
several joints in the
ankle be a disadvan.
tage to a bird?

BIRDS 153

The ¢high hardly projects beyond the skin of the trunk,
as may be noticed in a plucked fowl. The thigh extends
forward from the hip joint (Figs. 286, 299) in order to bring
the point of support forward under the centre of weight.
Why are long front toes more necessary than long hind toes ?
As the bird must often bring its head to the ground, the
hip joints are near the dorsal surface and the body swings
between the two points of support somewhat like a silver
ice pitcher on its two pivots. Hence stooping, which makes
a man so unsteady, does not cause a bird to lose steadiness.

The wing has three divisions which correspond to the
upper arm, the forearm, and the hand of man (Fig. 286).
When the wing is folded, the three divisions lie close
alongside one another. Fold your armin thesame manner.
The similarity of the bones.of the first and second divisions
to the bones of our upper arm and forearm is very obvious
(Fig. 286). Ex-
plain. The Zand of
a bird is furnished
with only three dig-
its (Fig. 287). The

Fss, 287,— HAND AND WRIST OF FOWL

three palm bones (after Parker).
(metacarpals) are DG. 1-3, digits; MC. 1-3, metacarpals;
CC. 3, wrist.

firmly united (Fig.
287). This gives
firmness to the
stroke in flying.
That the bird is

descended from ant- FIG. 288.— HAND, WRIST (0), FOREARM, AND
: LBOW OF YOUNG CHICK (after Parker).
mals which had the z 3 (Gin Bee)

fingers and palm bones less firmly united is shown by
comparing the hands of a chick and of an adult fowl
(Figs. 287, 288). The wrist also solidifies with age, the

154 BEGINNERS’ ZOOLOGY

five carpals of the chick being reduced to two in the fowl
(Figs. 287, 288). The thumb or first digit has a covering
of skin separate from that of the other
digits, as may be seen in a plucked bird.
The degenerate hand of the fowl is of
course useless as a hand (what serves
in its place?) but it is well fitted for
firm support of the feathers in flying. The
two bones of the forearm are also firmly
eee ee joined. There are eighteen movable
SON AND SHout.» -JOlnts, in ourcarm)andthands> @he* bird
DER Bones oF has only the three joints which enable
Se it to fold its wing. The wrist joint is
the joint in the forward angle of the wing.
Since the fore limbs are taken up with loco-
motion, the grasping function has been as-
sumed by the yaws. How does their
shape adapt them to this use? For
the same reason the zeck of a bird
surpasses the necks of all other ani-
mals in what respect? Is the trunk
of a bird
flexible or
inflexible ?
There is

thus a corv-
velation between struc-
ture of neck and trunk.
Explain. ~ The” same
correlation is found in
which of the reptiles ? Fic. 290.—A FossIL BIRD (archeopteryx)
(Why does rigidity of found in the rocks of a former geological
trunk require flexibility aes ; ee

Question: Find two resemblances to reptiles in

of neck ?) Why does this extinct bird absent from skeletons of extant birds.

BIRDS 155

the length of neck in birds correlate with the length of
legs? Examples? (See Figs. 314, 315, 332-) Exceptions?
(Fig. 324.) Why does a swan or a goose have a long
neck, though its legs are short ?

To make a firm support for the wings the vertebre of
the back are immovably joined, also there are three bones
in each shoulder, the collar bone,
the shoulder blade, and the
coracoid bone (Fig. 286). The
collar bones are united (why ?)
and form the “wishbone” or

’

“pulling bone.” To furnish sur-
face for the attachment of the
large flying muscles there is a
prominent ridge or keel on the
breastbone (Fig. 286). It is
lacking in most birds which do
not fly (Fig. 289).

The feathers are perhaps the a
most characteristic feature of
birds. The large feathers of the
wings and tail are called guz//
feathers. A quill feather (Fig.
291) is seen to consist of two 3
parts, the saf/, or supporting — Fic. 291.— Quit FEATHER
axis, and the broad vane or web. By dom ncn He De
What part of the shaft is round? Hollow? Solid? Is
the shaft straight? Are the sides of the vane usually
equal in width? Can you tell by looking at a quill whether
it belongs to the wing or the tail, and which wing or which
side of the tail it comes from? Do the quills overlap
with the wide side of the vane above or beneath the next
feather? Can you cause two parts of the vane to unite again

fs

A)
A
iy
in

Ai
ah

a
‘@

156 BEGINNERS’ ZOOLOGY

by pressing together the two sides of a split in the vane ?
Does the web separate at the same place when pulled until
it splits again?
The hollow part of the
shaft of a quill feather is
called the guz//. The part
of the shaft bearing the
vane is called the zachis
(ra-kis). The vane consists
of slender dards which are
branches of the shaft (II,
Fig. 292). As the name
indicates (see dictionary), a
barb resembles a hair. The
barbs in turn bear second-
Fic. 292.—1, Contour Featuer. ary branches called dar-
II, III, PARTS OF QUILL FEATHER, bules, and these again have
ine shorter branches called dar-
bicels (III, Fig. 292). These are sometimes bent in the
form of hooklets (Fig. 292, III), and the hooklets of
neighbouring barbules interlock, giv-
ing firmness to the vane. When two \
barbules are split apart, and then re-

yf

Ye

united by stroking the vane between

the thumb and the finger, the union
may be so strong that a pull upon
the vane will cause it to split in a
new place next time.

There are four kinds of feathers, é
(1) the gal? feathers, just studied ; Fic. 293. —A Down
(2) the contour feathers (I, Fig. 292), REATHER tenlaape as
which form the general surface of the body and give it its
outlines ; (3) the downy feathers (Fig. 293), abundant on

BIRDS 157

nestlings and found among the contour feathers of the
adult but not showing on the surface; (4) the fz feathers,
which are hair-like, and which are removed from a plucked
bird by singeing. The contour feathers are similar in
structure to the quill feathers. They protect the body
from blows, overlap so as to shed the rain, and, with the
aid of the downy feathers, retain the heat, thus accounting
for the high temperature of the bird. The downy feathers
are soft and fluffy, as they possess few or no barbicels;
sometimes they lack the rachis (Fig. 293). The pin feath-
ers are delicate horny shafts, greatly resembling hairs, but
they may have a tuft of barbs at the ends.

A feather grows froma small projection (or papilla) found
at the bottom of a depression of the skin. The quill is
formed by being moulded around the papilla. Do you see
any opening at the tip of the quill for blood vessels to enter
and nourish the feather? What isin the quill? (Fig. 291.)
The rachis? A young con-
tour or quill feather is in-
closed in a delicate sheath
which is cast off when the
feather has been formed.
Have you seen the sheath
incasing a young feather in
a moulting bird?

There are considerable
areas or tracts on a bird’s

: FIG. 294.—DORSAL AND VENTRAL
skin without contour feath- VIEW QF PLUCKED BIRD, showing
ers. Such bare tracts are eee
found along the ridge of the breast and on the sides of
the neck. However, the contour feathers lie so as to over-
lap and cover the whole body perfectly (Fig. 294).

The shedding of the feathers is called moulting. Feathers,

158 BEGINNERS’ ZOOLOGY

like the leaves of trees, are delicate structures and lose

perfect condition with age. Hence the annual renewal

FIG. 295.— WING OF BIRD.

Z, false quills (on thumb); 2, primaries; 3, secondaries;
tertiaries (dark) are one above another at right;
a, 6, coverts.

of the feathers is
anadvantage. Most
birds shed twice a
year, and with many
the summer plum-
age is brighter col-
oured than the win-
ter plumage. When
a feather is shed on
one side, the corre-
sponding feather on
the. other side" as

always shed with it. (What need for this?) A large

owl gland is easily found on the
dorsal side of the tail. How does
the bird apply the oil to the
feathers ?

FIG. 296.

A, point dividing primaries from second-

aries; B, coverts. FIG. 297. —CEDAR WAXWING,

In describing and classifying
birds, it is necessary to know the
names of the various external
regions of the body and plum-
age. These may be learned by
studying Figs. 295, 296, 297, 298.

with regions of body marked.

S, forehead; Sc, crown (with crest);
Hh, nape; XK, throat; By, breast;
Ba, lower parts; A, back; Rz, tail;
B, tail coverts; ?, shoulder feathers
(scapulars) ; 7, wing coverts; AS,
primaries; AS, secondaries; Ad,
thumb feathers.

The quills on the hand

BIRDS 159

are called primaries, those on the forearm are the sec-
ondaries, those on the upper arm are the tertiaries. Those
on the tail are called the ¢az/ guzl/s. The feathers at the
base of the quills are called the coverts. The thum > bears
one or more quills called the spurious quills. Is the wing
concave on the lower or the upper
side? Of what advantage is this
when the bird is at rest? When
it is flying ?

Control of Flight. — Did you ever
see a bird sitting on a swinging
limb? What was its chief means
of balancing itself ? When flying,
what does a bird do to direct its
course upward? Downward? Is
the body level when it turns to

FIG. 298. PLAN OF BIRD.
either side? Birds with long, s, centre of gravity.

pointed wings excel in what respect? Examples? Birds
with great wing surface excel in what kind of flight? Ex-
amples. Name a common bird with short wings which
has a laboured, whirring flight. Is its tail large or small ?

Does it avoid obstacles and direct its
flight well? Why or why not? When
a boat is to be turned to the right,
must the rudder be pulled to the right
or to the left? (The rudder drags in
the water and thus pulls the boat
around.) When the bird wishes to

FIG. 299.— POSITION OF go upward, must its tail be turned up
LIMBS OF PIGEON.

or down? How when it wishes to go
down? When a buzzard soars for an hour without flapping
its wings, does it move at a uniform rate? For what does
it use the momentum gained when going with the wind ?

160 BEGINNERS’ ZOOLOGY

Flying. — When studying the quill feathers of the wing,
you saw that the wider side of the vane is beneath the
feather next behind it. During the downward stroke of
the wing this side of the vane is pressed by the air against

FIG. 300.

a, clambering foot of chimney sweep; 4, climbing foot of woodpecker; ¢, perching foot of
thrush; d, seizing foot of hawk; e, scratching foot of pheasant; /, stalking foot of king-
fisher; g, running foot of ostrich; 4, wading foot of heron; 2, paddling foot of gull;
#, swimming foot of duck; 2, steering foot of cormorant; 2, diving foot of grebe; 2, skim-
ming foot of coot. Question: Does any bird use its foot asa hand? (Fig. 320.)

the feather above it and the air cannot pass through the
wing. As the wing is raised the vanes separate and
the air passes through. The convex upper surface of
the wing also prevents the wing from catching air as
it is raised. Spread a wing and blow strongly against

BIRDS 161

its lower surface; its upper’ surface, What effects are
noticed ?

Study the scales on the leg of a bird (Fig. 300). Why is
the leg scaly rather than feathered from the ankle down-
ward? Which scales are largest? (Fig. 300.) How do
the scales on the front and the back differ? What can you
say of the scales at the bottom of the foot; at the joints
of the toes? Explain. How does the covering of the

nails and the bill compare in colour, texture, hardness,and
firmness of attachment with the scales of the leg?

Draw an outline of the bird seen from the side. Make
drawings of the head and the feet
more detailed and on a larger
scale.

Why does a goose have more
feathers suitable for making pil-

BS
lows than has a fowl? In what LY ea ee ee

country did the domestic fowl i.e. poorly developed at hatch-
originate? (Encyclopedia.) Why py sown ctme
does a cock crow for dawn?
(Consider animal life in jungle.)

Activities of a Bird. — Observe
a bird eating. Does it seem to
chew or break its food before
swallowing? Does it have to
lift its head in order to swallow
food? To swallow drink ? Why

ds) Phebe apditherence? After feed-, (16. 302-4 Paxcocian/Biep
(well developed at hatching).

ing the bird, can you feel the Feathered, able to run and to

TeOdMEm tneleropzor-enlarsement .~ Pick ep food. “Brecocity-is a

sign of instinctive life and low

of the cullet at the base of the intelligence. A baby is not pre-
neck? (Fig. 304.) cocious.

Question: Is pigeon or fowl ex-

Feel and look for any move- posed to more dangers in infancy ?

162 BEGINNERS’ ZOOLOGY

ments in breathing. Can you find how often it breathes
per minute? Place hand under the bird’s wing. What
do you think of its ¢emperature ; or better, what tempera-
ture is shown by a thermometer held under its wing? Do
you see any connection between the breathing rate and the
temperature? Test (as with the crayfish) whether a bird
can see behind its head? Notice the movements of the
nictitating membrane. Does it appear to be transparent ?

Watch a bird fy around a closed room and review the
questions on Control of Flight.

Lend a bird’s leg and see if it has any effect upon its
toes. Notice a bird (especially a large fowl) walk, to see
if it bends its toes as the foot is lifted. Pull the rear
tendon in a foot cut from a fowl for the kitchen. Does
the bird have to use muscular exertion to grasp a stick
upon which it sits? Why, or why not? When is this
bending of the toes by bending the legs of special ad-
vantage toa hawk? Toa duck? To a wading bird? Why
is a fowl safe from a hawk if it stands close to a tree ?

Do you see any signs of teeth in the bird’s jaws? Why
are duck’s “teeth” (so called by children) not teeth ?
if Can the tongue of a bird be
pulled forward? (Fig. 303.)
What is its shape? If there
is opportunity, dissect and
study the slender, bony
(hyoid) apparatus to which
the base of the tongue is
attached (Fig. 303), the open-
é,tongue: @, 4, ¢,hyeid bone: eigewinds | WS Ol the wwindpipe, ior

pipe: Js Babwesy elena trachea, the slit-like opening
of windpipe, which is so narrow as to prevent food falling
into the windpipe.

FIG, 303. — HEAD OF WOODPECKER.

BIRDS 163

The Internal Organs, or Viscera (Figs. 304 and 305).
— The viscera (vis'se-ra), as in most vertebrates, zzclude
the food tube and its glands; the lungs, the heart, and the
larger blood vessels; the kidneys and bladder and the
reproductive organs. The lower part, or gullet, is en-
larged into a cvop. It is largest in grain-eating birds. It

FIG. 304. — ANATOMY OF DOVE x%.

6k, keel of breastbone; G, g, brain; dr,
windpipe; Zz, lung; #, heart; sz, gul-
let; #, crop; dr, glandular stomach;
mm, gizzard; d, intestine; 2, kidney;
hl, ureter; ez7, openings of ureter and Question: Identify each part by means
egg duct into cloaca, £2. of Fig. 304.

FIG. 305. — FooD TUBE OF BIRD.

P, pancreas; C, ceca.

is found in the V-shaped depression at the angle of the
wishbone, just before the food tube enters the thorax.
The food is stored and softened in the crop. From the
crop the food passes at intervals into the glandular stomach.
Close to this is the muscular stomach, or gizzard. Are the
places of entrance and exit on opposite sides of the gizzard,
or near together? (Fig. 304.) Is the lining of the gizzard

164 BEGINNERS’ ZOOLOGY

rough or smooth? Why? Is the gizzard tough or weak?
Why are small stones in the gizzard? Why do not hawks
and other birds of prey need a muscular gizzard? The
liver and pancreas empty their secretions into the intestines
by several ducts a little way beyond the gizzard. Beyond
the mouths of two ceca (Fig. 305) the many-coiled
intestine empties into the straight
rectum, which terminates in a
widened part called the cloaca.
Not only the intestine, but the
two ureters of the urinary system
and the two genital ducts of the
reproductive system all empty into
the cloaca (Figs. 304, 305).

The lungs have their rear sur-
faces attached to the spinal
column and ribs (du, Fig. 304).
They are connected with thin-
walled, transparent azr sacs which
aid in purifying the blood. When
inflated with warm air, they prob-

FIG. 306.—Position oF Luncs ably make the body of the bird

AND AIR SAacs (Pigeon). more buoyant. For the names,
Tr, windpipe; P, lungs; Zs, sac
under clavicle with prolongation

(24) into humerus; Za, sacsin pairs of air sacs, see Fig. 306.
i coe The connection of the air sacs with
hollows in the humerus bones is also shown in the figure.
Many of the dones are hollow; this adds to the buoyancy of

location, and shape of several

the bird. The pulmonary artery, as in man, takes dark
blood to the lungs to exchange its carbon dioxide for
oxygen. Of two animals of the same weight, which ex-
pends more energy, the one that flies, or the one that runs
the same distance? Does a bird require more oxygen

BIRDS

165

or less, in proportion to its weight, than an animal that

lives on the ground? Are
higher or lower in the wind-
pipe than those of a man?
(Fig..307.)

The heart of a bird, like a
man’s heart, has four cham
bers; hence it keeps the
purified blood separate from
the impure blood. Since
pure blood reaches the’ or-
gans of a bird, oxidation is
more perfect than in the
body of any animals yet
studied. Birds have higher

the vocal chords of a bird

A B

OK vee )
tr te
uk Ase
lu lu

FIG. 307. — POSITION OF VOCAL
CORDS (st7) OF MAMMAL AND BIRD.
Question: Does a fowl ever croak after
its head and part of its neck are cut off?
. Explain,

temperature than any other class of animals whatsoever.

Tell how the jaws, the tail, and the wings of the fossil
bird Archeopteryx differed from living birds (Fig. 290).

SUGGESTIONS.— In the field work, besides seeking the answers to
definite questions, pupils may be required to hand in a record of the
places and the times of seeing a certain number of birds (20-40) with
the actions and features which made each distinguishable. Also, and
more important, each pupil should hand ina record of a careful and
thorough outdoor study of one common species (see below) as regards
habits, nesting, relation to environment, etc.

Field Study of a Common Species. — (for written report.)
Name of species. aunts. Method of locomotion when not
flying. /Zyng (rate, sailing, accompanying sound if any, soaring).

What is the food? How obtained? Associaton with birds of
its own species. e/ation to birds of other species.

Where does it build its zes¢? Why is such a situation selected ?
Of what is the nest built? How is the material carried, and
how built into the nest? Does the bird’s body fill the nest?

Describe the eggs. Does the male bird ever sit or otherwise
assist female before hatching? Does it assist after hatching?

BEGINNERS’ ZOOLOGY

How long is taken to lay
a sitting of eggs? How
long before the birds are
hatched? When hatched
are they helpless? Blind?
Feathered? (Figs. 301,
302.) Do-° the ~nest-
lings require much food ?

How many times in an
hour is food brought?

How distributed? Even
if the old birds some-
times eat fruit do they
take fruit to the young?
What do they feed to the
young? How long be-

FIG. Bee ~ EUROPEAN ToMTIT's s “NEST.
What are the advantages of its shape ?

fore they leave the nest?
Do the parents try to teach
them to fly? Do the par-
ents care for them after the
nest is left? What songs or
calls has the bird?

General Field Study.
—(For written report.)
Name the best and poor-
est flyers you know;
birds that fly most of the
time; birds that seldom
fly. Observe birds that

pair; live in flocks. Does Fic.

their sociability
with the season?

vary

309. — TAILOR BIRD'S NEST (India).
Instinct for nest building highly perfected,

Do youever see birds quarrelling? _

BIRDS 167

Fighting? What birds do you observe whipping or driving
birds larger than themselves? Which parent do young
birds most resemble? Name the purposes for which birds
sing. Which senses are very acute? Why? Dull? Why?
Can you test your statements by experiment? A part-
ridge usually sits with 18 to 24 eggs in nest. About how
long after laying first egg before sitting begins? Do
several partridge hens lay in the same nest?

Haunts.—Name some!
birds that are found most,
often in the following lo:
calities: about our homes,
in gardens and orchards,
fields and meadows, in
bushes, in the woods, in
secluded woods, around
streams of water, in
thickets, in pine woods.

Size-—Name birds as
large as a robin or larger,
nearly as large, half as
large, much smaller.

Colours.—Which sex is more brilliant? Of what advant-
age are bright colours toone sex? Of what advantage are
dull colours to the other sex? Which have yellow breasts,
red patchon heads, redor chestnut breasts, blue backs,
black all over?

Habits —Name the birds that walk, jump, swim, live in
flocks, sing while flying, fly in undulations, in circles,
have laboured flight.

Economic Importance of Birds. — Farmers find their
most valuable allies in the class aves, as birds are the dead-
liest enemies of insects and gnawing animals. To the in-
numerable robbers which devastate our fields and gardens,
nature opposes the army of birds. They are less numerous

FIG. 310.— HOUSE WREN.

FIG. 311. —SCREECH OWL (Megascops asio).

Question: Compare posture of body, position of
eyes, and size of eyes, with other birds.

BEGINNERS’ ZOOLOGY

than insects and other
robbers, it is true, but
they are skilful and
zealous in pursuit, keen
ofeye, quick active,
and remarkably vora-
cious. The purely in-
sectivorous birds are
the most useful, but the
omnivorous and grami-
nivorous birds do not
disdain The
perchers and the wood-
peckers should be pro-

tected most carefully.

insects.

The night birds of prey

(and those of the day to a less degree) are very der nenee

to field mice, rabbits, and other
gnawing animals. Some igno-
rant farmers complain continu-
ally about the harm done by
birds. To destroy them is as
unwise as it would be to destroy
the skin which protects the hu-
man body because it has a spot
upon it! It cannot be repeated
too plainly that to hunt useful
birds is a wrong and mischievous
act, and it is stupid and barba-
rous to destroy their nests.
Injurious birds are few. Of
course birds which are the ene-
mies of other birds are enemies

Fic. 312. — GOSHAWK,
or chicken hawk.

FIG. 313. mes Junta or pene bird (Vex. to Cal.). What order?
(Key, p. 177-)

of mankind, but examples are scarce (some owls and
hawks). Many birds of prey are classed thus by mistake.
Sparrow-hawks, for instance, do not eat birds except in
rare instances; they feed chiefly upon insects. A sparrow
hawk often keeps watch over a field where grasshoppers
are plentiful and destroys great numbers of them. When
a bird is killed because it is supposed to be injurious, the
crop should always be examined, and its contents will often
surprise those who are sure it is a harmful bird. The
writer once found two frogs, three grasshoppers, and five
beetles that had been swallowed bya “chicken hawk”
killed by an irate farmer, but no sign of birds having been
used for food. owls should not be raised in open places,
but among trees and bushes, where hawks cannot swoop.
Birds which live exclusively upon fish are, of course,
opposed to human interests. Pigeons are destructive to
grain; eagles feed chiefly upon other birds.

If the birds eat the grapes, do not kill the birds, but plant
more grapes. People with two or three fruit trees or a small

170 BEGINNERS’ ZOOLOGY

garden are the only ones that lose a noticeable amount of
food. We cut down the forests from which the birds ob-
tain part of their food. We destroy insect pests at great
cost of spraying, etc. The commission the birds charge
for such work is very small indeed. (See pages 177-183.)

{\ LN Hy v
Wj of Se a

_

iZ

Lie

FIG. 314.— WooD DUCK, male (Azx sfonsa). Nests in hollow trees throughout
North America. Also called summer duck in South. Why ?

The English sparrow is one bird of which no good word
may be said. Among birds, it holds the place held by rats
among beasts. It is crafty, quarrelsome, thieving, and a
nuisance. It was imported in 1852 to eat moths. The
results show how ignorant we are of animal life, and how
slow we should be to tamper with the arrangements of
nature. In Southern cities it produces five or six broods
each year with four to six young in each brood. (Notice
what it feeds its young.) It fights, competes with and
drives away our native useful birds. It also eats grain and
preys upon gardens. They have multiplied more in Aus-

BIRDS 171

tralia and in North America than in Europe, because they
left behind them their native enemies and their new ene-
mies (crows, jays, shrikes, etc.) have not yet developed, to
a sufficient extent, the habit of preying upon them. Nature
will, perhaps, after a long time, restore the equilibrium
destroyed by presumptuous man.

Protection of Birds.—1. Leaveas many trees and bushes
standing as possible. Plant trees, encourage bushes.

2. Do not keep acat. A mouse trap is more useful than
acat. A tax should be imposed upon owners otf cats.

3. Make a bird house and place it on a pole; remove
bark from pole that cats may not climb it; or put a broad
band of tin around the pole.

4. Scatter food in winter. In dry regions and in hot
weather keep a shallow tin vessel containing water on the
roof of an outhouse, or in an out-of-the-way place, for
shy birds.

5. Do not wear feathers obtained by the killing of birds. —
What feathers are not so obtained ?

6. Report all violators of laws for protection of birds.

7. Destroy English sparrows.

Migration. — Many birds, in fact most birds, migrate to
warmer climates to spend the winter. Naturalists were
once content to speak of the migra-
tion of birds as a wonderful instinct,
and made no attempt
to: (expla, 7it; “As
birds have the warmest covering
of all animals, the winter mi-

gration is not for the pur-

FIG. 315.—GREaT BLUE Heron. Pose of escaping the cold; it

In flight, balancing with legs. is probably to escape starva-
tion, because in cold countries food is largely hidden by
snow in winter. On the other hand, if the birds remained

172 BEGINNERS’ ZOOLOGY

in the warm countries in summer, the food found in north-
ern countries in summer would be unused, while they
would have to compete with the numerous tropical birds
for food, and they and their eggs would be in danger from
snakes, wild cats, and other beasts of prey so numerous in
warm climates. These are the best reasons so far given
for migration.

The manner and methods of migration have been studied
more carefully in Europe than in America. Migration is

FIG, 316, — EUROPEAN SWALLOWS (Hirundo urbica), assembling for autumn
flight to South.
not a blind, infallible instinct, but the route is learned and
taught by the old birds to the young ones; they go in
flocks to keep from losing the way (Fig. 316); the oldest
and strongest birds guide the flocks (Fig. 317). The birds
which lose their way are young ones of the last brood, or
mothers that turn aside to look for their strayed young.
The adult males seldom lose their way unless scattered
by a storm. Birds are sometimes caught in storms or
join flocks of another species and arrive in countries
unsuited for them, and perish. For example, a sea or

BIRDS 173

marsh bird would die of hunger on arriving in a very dry
country.

The landmarks of the route are mountains, rivers, valleys,
and coast lines. This knowledge is handed down from one
generation to another. It includes the location of certain
places on the route where food is plentiful and the birds
can rest in security. Siebohm and others have studied

the routes of migration in the Old
World. The route from
the nesting places in|

northern Eu-

Africa fol- f
lows the Rhine,
the Lake of Geneva,
the Rhone, whence some spe-
cies follow the Italian and others the Span- pig. 317 Cranes
ish coast line to Africa. Birds choose the Micratine, with
lowest mountain passes. The Old World can oe 2
martin travels every year from the North
Cape to the Cape of Good Hope and back again! An-
other route has been traced from Egypt along the coast
of Asia Minor, the Black Sea and Ural Mts. to Siberia.
Field Study of Migration. —Three columns may be filled
on the blackboard in an unused corner, several months in
spring or fall being taken for the work. First column, birds
that stay all the year. Second column, birds that come
from the south and are seen in summer only. Third
column, birds that come from the north and are seen in
winter only. Exact dates of arrival and departure and
flight overhead should be recorded in notebooks. Many
such records will enable American zoologists to trace the
migration routes of our birds.

rope to

174 BEGINNERS’ ZOOLOGY

Moulting —How do birds arrange their feathers after
they have been ruffled? Do they ever bathe in water?

FIG, 318. —APTERYX, of New Zealand. Size of a hen, wings and tail
rudimentary, feathers hair-like.

In dust? Dust helps to remove old oil. At what season
have birds the brightest feathers? Why? Have you ever

FIG. 319. —GOLDEN, SILVER, AND NOBLE PHEASANTS, males. Order?
(Key, p. 177.) Ornaments of males, brightest in season of courtship, are due to
sexual selection (Figs. 321-7-9, 333)-

seen evidence of the moulting of birds? Describe the
moulting process (page 120).

BIRDS 175

Adaptations for
Flying. — Flight
is the most diff-
cult and energy-
consuming meth-
od of moving
found among ani-
mals, and care-
ful adjustment is
necessary... ~For
balancing, the
heaviest muscles
are placed at the
lower and central
portion of the body.
These are the flying
muscles, and in some
birds (humming birds)
they make half of the
entire weight. Teeth
are the densest of ani-
mal structures; teeth
and the strong chew-
ing muscles required
would make the head. pyc, 307. Birp oF
heavy and_ balancing PARADISE (Asia).
difficult; hence the chewing apparatus is
transferred to the heavy gizzard near the
centreof gravity of the body. The bird’s
neck is long and excels all other necks in
flexibility, but it is very slender (although
apparently heavy), being inclosed in a
loose, feathered skin. A cone is the best

FIG. 320.
CocKATOO.

SS
—S

SSAA

176 BEGINNERS’ ZOOLOGY

shape to enable the body to penetrate the air, and a small
neck would destroy the conical form. The internal organs
are compactly arranged and rest in the cavity of the breast
bone. The bellows-like air sacs filled with warm air
lighten the bird’s weight. The bones are hollow and very
thin. The large tail quills are used by the bird only in
guiding its flight up and down, or balancing on a limb.
The feet also aid a
flying bird in bal-
ancing. The wing

is so constructed as
to present to the
air a remarkably

large surface com-
pared with the
small bony support
in the wing skele-

ton. Are tubes

FIG, 322. HERRING GULL. (Order ?)

ever resorted to by
human architects when lightness combined with strength
is desired? Which quills in the wing serve to lengthen
it? (Fig. 296.) To broaden it? Is flight more difficult
for a bird or for a butterfly? Which of them do the flying
machines more closely resemble? Can any bird fly for a
long time without flapping its wings?

Exercise in the Use of the Key. — Copy this list and write the name
of the order to which each of the birds belongs. (Key, page 177.)

Cockatoo (Fig. 320) Wren (Fig. 310) Pheasant (Fig. 319)

Sacred Ibis (Fig. 328) Apteryx (Fig. 318) Wood Duck (Fig. 314)

Screech Owl (Fig. 311) Lyre bird (Fig. 327) Jacana (Fig. 324)

Nightingale (Fig. 325) Road Runner (Fig. 313) Sea Gull (Fig. 322)

Top-knot Quail (Fig. Ostrich (Fig. 332) Heron (Fig. 315)
329) Penguin (Fig. 330) Hawk (Fig. 312)

BIRDS 177

KEY, OR TABLE, FOR CLASSIFYING BIRDS (Class Aves)
INTO ORDERS
ORDERS
A, Wings not suited for flight, 2 or 3 toes RUNNERS
A, Wings suited for flight (except the penguin)
B, Joes united by a web for swimming, legs short
C, Feet placed far back ; wings short, tip not DIVERS
reaching to base of tail (Fig. 300)
C, Bill flattened, horny plates under margin BILL-STRAINERS
of upper bill (Fig. 323)

C, Wings long and pointed, bill slender SEA-FLIERS
C, All four toes webbed, bare sac under GORGERS
throat

B, Joes not united by web for swimming
C, Three front toes, neck and legs long, tibia © WADERS
(shin, or “ drumstick”) partly bare
C, Three front toes, neck and legs not long
D, Claws short and blunt (e, Fig. 300)
E, Feet and beak stout, young feathered, SCRATCHERS
base of hind toe elevated
E, Feet and beak weak, young naked MESSENGERS
D, Claws long, curved and sharp, bill ROBBERS
hooked and sharp
‘D, Claws long, slightly curved, bill nearly ©§ PERCHERS

straight
C, Two front and two hind toes (Fig. 300)
D, Bill straight, feet used for climbing FOOT-CLIMBERS
D! Bill hooked, both bill and feet used for BILL-CLIMBERS
climbing

The Food of Birds.— Extracts from Bulletin No. 54
(United States Dept. of Agriculture), by F. E. L. Beal.

The practical value of birds in controlling insect pests should
be more generally recognized. It may be an easy matter to
exterminate the birds in an orchard or grain field, but it is an
extremely difficult one to control the insect pests. It is certain,
too, that the value of our native sparrows as weed destroyers is
not appreciated. Weed seed forms an important item of the
winter food of many of these birds, and it is impossible to estimate
the immense numbers of noxious weeds which are thus annually

178 BEGINNERS” ZOOLOGY

destroyed. If crows or blackbirds are seen in numbers about
cornfields, or if woodpeckers are noticed at work in an orchard,
it is perhaps not surprising that they
are accused of doing harm. Careful in-
vestigation, however, often shows that
they are actually destroying noxious in-
sects ; and also that even those which
do harm at one season may compensate
for it by eating insect pests at another.
Insects are eaten at all times by the
majority of land birds. During the
breeding season most kinds subsist largely on this food, and rear
their young exclusively upon it. ;
Partridges. — Speaking of 13 birds which he shot, Dr. Judd says:
These 13 had taken weed seed to the extent of 63 per cent of

FIG. 323. — HEAD OF DUCK.

FIG. 324.— JACANA. (Mexico, Southwest Texas, and Florida.)

Questions: What appears to be the use of such long toes? _ What peculiarity of wing? head?

their food. Thirty-eight per cent was ragweed, 2 per cent tick
trefoil, partridge pea, and locust. seeds, and 23 per cent seeds of
miscellaneous weeds. About 14 per cent of the quail’s food for

BIRDS 179

the year consists of animal matter (insects and their allies).
Prominent among these are the Colorado potato beetle, the
striped squash beetle, the cottonboll-weevil, grasshoppers. As a
weed destroyer the quail has few, if any, superiors. Moreover,
its habits are such that it is almost constantly on the ground,
where it is brought in close contact with both weed seeds and
ground-living insects. It is a good ranger, and, if undisturbed, will
patrol every day all the fields in its vicinity as it searches for food.

FIG. 325.— NIGHTINGALE, x 3, FIG. 326.— SKYLARK, X 3,

Two celebrated European songsters,

Doves. — The food of the dove consists of seeds of weeds,
together with some grain. The examination of the contents of
237 stomachs shows that over 99 per cent of the food consists
wholly of vegetable matter.

Cuckoos. — An examination of the stomachs of 46 black-billed
cuckoos, taken during the summer months, showed the remains
of 906 caterpillars, 44 beetles, 96 grasshoppers, 100 sawflies, 30
stink bugs, and 15 spiders. Of the yellow-billed cuckoos, or
“ rain-crow,” 109 stomachs collected from May to October, in-
clusive, were examined. The contents consisted of 1,865 cater-
pillars, 93 beetles, 242 grasshoppers, 37 sawflies, 69 bugs, 6 flies,
and 86 spiders.

180 BEGINNERS’ ZOOLOGY

Woodpeckers. — Careful observers have noticed that, excepting
a single species, these birds rarely leave any conspicuous mark on
a healthy tree, except when it is affected by wood-boring larve,
which are accurately located, dis- sf
lodged, and devoured by the wood- aS
pecker. Of the flickers’ or yellow-
hammers’ stomachs examined, three
were completely filled with ants.
Two of the birds each
contained more than
3,000 ants, while the
third bird contained fully
5,000. These ants be-
long to species which
live in the ground. It is
these insects for which
the flicker is reaching
when it runs about in the
grass. The yellow-bellied
woodpecker or sapsucker
(Sphyrapicus varius) was shown to be guilty of pecking holes in
the bark of various forest trees, and sometimes in that of apple
trees, and of drinking the
sap when the pits became
filled. It has been proved,
however, that besides tak-
ing the sap the bird cap-
tures large numbers of
insects which are attracted
by the sweet fluid, and
that these form a very
considerable portion of
its diet. The woodpeck-
ers seem the only agents
which can __ successfully
cope with certain insect enemies of the forests, and, to some
extent, with those of fruit trees also. For this reason, if for no
other, they should be protected in every possible way.

FIG. 327.— LYRE BIRD, male,

FIG. 328. SACRED Ibis. (Order ?)

BIRDS 181

The night hawk, or “ bull bat,’’ may be seen most often soaring
high in air in the afternoon or early evening. It nests upon rocks or
bare knolls and flat city roofs. Its food consists of insects taken
on the wing ; and so greedy is the bird that when food is plentiful,
it fills its stomach almost to bursting. Ants (except workers) have
wings and fly as they are preparing to propagate. In destroying
ants night hawks rank next to, or even with, the woodpeckers, the
acknowledged ant-eaters among birds.

FIG. 329. — TOP-KNOT QUAIL, or California Partridge.
(West Texas to California.)

The kingbird, or martin, is largely insectivorous. In an ex-
amination of 62 stomachs of this bird, great care was taken to
identify every insect or fragment that had any resemblance to a
honeybee ; as a result, 30 honeybees were identified, 6f which 29
were males or drones andr was a worker.

Blue Jay. — In an investigation of the food of the blue jay 300
stomachs were examined, which showed that animal matter com-
prised 24 per cent and vegetable matter 76 per cent of the bird’s
diet. The jay’s favourite food is mast (¢.¢..acorns, chestnuts,
chinquapins, etc.), which was found in 200 of the 300 stomachs,
and amounted to more than 42 per cent of the whole food.

182 BEGINNERS’ ZOOLOGY

Crow. — That he does pull up sprouting corn, destroy chickens,
and rob the nests of small birds has been repeatedly proved. Nor
are these all of his sins. He is known to eat frogs, toads, sala-
manders, and some small snakes, all
harmless creatures that do some good
by eating insects. Experience has
shown that they may be prevented
from pulling up young corn by tarring
the seed, which not only saves the
corn but forces them to turn their at-
tention to insects. May beetles, “ dor-
bugs,” or June bugs, and others of
the same family constitute the princi-
pal food during spring and early sum-
mer, and are fed to the young in
FIG. 330.— PENGUINOF PaTa- immense quantities.

GONIA. Wings used as flip- Ricebird.— The annual loss to rice
pesoior Swans growers on account of bobolinks has
been estimated at $2,000,600.

Meadow Lark.— Next to grasshop-
pers, beetles make up the most impor-
tant item of the meadow lark’s food,
amounting to nearly 21 per cent.
May is the month when the dreaded
cut«worm begins its deadly career, and
then the lark does some of its best
work. Most of these caterpillars are
ground feeders, and are overlooked
FIG. 331.— Umbrella holding by birds which habitually frequent

the nests of social weaver trees, but the meadow lark finds and

bird of Africa; polygamous. devours them by thousands.

Sparrows. — Examination of many stomachs shows that in
winter the tree sparrow feeds entirely upon seeds of weeds.
Probably each bird consumes about one fourth of an ounce a
day. Farther south the tree sparrow is replaced in winter by the
white-throated sparrow, the white-crowned sparrow, the fox spar-
row, the song sparrow, the field sparrow, and several others; so
that all over the land a vast number of these seed eaters are at

BIRDS 183

work during the colder months reducing next year’s crop of worse
than useless plants.

Robin. —An examination of 500 stomachs shows that over
42 per cent of its food is animal matter, principally insects,
while the remainder is made up largely of small fruits or
berries. Vegetable food forms nearly 58 per cent of the stom-
ach contents, over 47 per cent being wild fruits, and only a
little more than 4 per cent being possibly cultivated varieties.
Cultivated fruit amounting to about 25 per cent was found
in the stomachs in June and July, but only a trifle in August.
Wild fruit, on the contrary, is eaten in every
month, and constitutes during half the year a P
staple food. <

Questions. — Which of these birds are com-
mon in your neighbourhood? Which of them
according to the foregoing report are plainly inju-
rious? Clearly beneficial? Doubtful? Which
are great destroyers
of weed _ seeds?
Wood-borers? Ants?
Grain? Why is the
destruction of an ant
by a night hawk of
greater benefit than
the destruction of an
ant by a woodpecker ?
Name the only wood-
pecker that injures
trees. If a bird eats
two ounces of grain
and one ounce of in-
sects, has it probably
done more good or

more evil? FIG. 332.— AFRICAN OSTRICH, X 2;, (Order ?)

CHAPTER, Atv

MAMMALS

SuccEstions. — A tame rabbit, a house cat, or a pet squirrel may
be taken to the school and observed by the class. Domestic ani-
mals may be observed at home and on the street. A study of the
teeth will give a key to the hfe of the animal, and the teacher
should collect a few mammalian skulls as opportunities offer. The
pupils should be required to identify them by means of the chart
of skulls (p. 194). If some enthusiastic students fond of anatomy
should dissect small mammals, the specimens should be killed with
chloroform, and the directions for dissection usual in laboratory
works on this subject may be followed. There is a brief guide on
page 223. The following outline for the study of a live mammal
will apply almost as well to the rabbit or the squirrel as to the cat.

The Cat. — The house cat (Felis domestica) is probably
descended from the Nubian cat (Fels maniculata, Fig. 333)
found in Africa. The wild species is about half as large
again as the domestic cat, grayish brown with darker
stripes; the tail has dark rings. The lynx, or wild cat
of America (Lyux rufus), is quite different. Compare the
figures (333, 335) and state three obvious differences.
To which American species is the house cat closer akin,
the lynx (Fig. 335) or the ocelot (Fig. 334)? The domes-
tic cat is found among all nations of the world. What is
concluded, as to its nearest relatives, from the fact that the
Indians had no cats when America was discovered? It
was considered sacred by the ancient Egyptians, and after
death its body was embalmed.

The body of the cat is very flexible. It may be divided
into five regions, head, neck, trunk, tail, and limbs. Its

184

MAMMALS 185

FIG. 333-— WILD CAT OF AFRICA (felis maniculata), X Y%.

eyes have the same parts as the eyes of other mammals.
Which part of its eye is most peculiar? (Fig. 333.) What
part is lacking that is present in birds? How are the eyes
especially adapted for seeing at night? Does the pupil in
the light extend up or down or across the iris? Does it
ever become round?

What is the shape and the position of the ears? Are they
large or small compared with those of most mammals?
They are fitted best for catching sound from what direc-
tion? What is thus indicated in regard tothe cat’s habits ?
(Compare with ears of rabbit.) Touch the wzskers of the
cat. What result? Was it voluntary or involuntary mo-
tion? Are the zoszrils relatively large or small compared
with those of acow? Of man?

Is the zeck long or short? Animals that have long fore
legs usually have what kind of neck? Those with short
legs? Why? Howmany goes ona fore foot? Hind foot?
Why is this arrangement better than the reverse? Some
mammals are sole walkers (plantigrade), some are toe
walkers (digitigrade). To which kind does the cat

186 BEGINNERS’ ZOOLOGY

A) Aa TETAS

x: Reese R ey

aye

FIG. 334.— OCELOT (Felis pardalis), of Texas and Mexico, x 2.

belong? Does it walk on the ends of thetoes? Does it
walk with all the joints of the toes on the ground? Where
is the /ee/ of the cat? (Fig. 334.) The wrist? To make
sure of the location of the wrist, begin above: find the-shoul-
der blade, the upper arm (one or two bones ?), the lower
arm (one or two bones?), the wrist, the palm, and the
fingers (Fig. 337). Is the heel bone prominent or small ?
In what direction does the kuce of the cat point? The
heel? The elbow? The wrist? Compare the front and
the hind Jeg in length; straightness; heaviness; number and
position of toes ; sharpness of the claws. What makes the
dog’s claws duller than a cat’s? What differences in habit
go with this? Judging from the toe that has become use-
less on the fore foot of the cat, which toe is lacking in the
hind foot? Is it the cat’s thumb or little finger that does
not touch the ground? (Fig. 337.) Locate on your own
hand the parts corresponding to the pads on the forefoot
of acat. Of what use are soft pads on a cat’s foot?
Some animals have short, soft fur and long, coarse over
hair. Does the cat have both? Is the cat’s fur soft or

coarse? Does the fur have a colour near the ‘skin different

.

MAMMALS 187

from that at the tip? Why is hair better suited as a cover-
ing for the cat than feathers would be? Scales? Where
are long, stiff bristles found on the cat? Their length
suggests that they would be of what use to a cat in going
through narrow places? Why is it necessary for a cat to
be noiseless in its movements ? .

FIG. 335.— LYNx (Lynx rufus). The “ Bob-tailed cat” (North America),

Observe the movements of the cat. — Why cannot a cat
come down a tall tree head foremost? Did you ever see a
cat catch a bird? How does a cat approach its prey?
Name a jumping insect that has long hind legs; an am-
phibian ; several mammals (Figs. 362, 374). Does a cat
ever trot? Gallop? Does a cat chase its prey? When
does the cat move with its heel on the ground? The
claws of a cat are withdrawn by means of a tendon (see
Fig. 338). Does a cat seize its prey with its mouth or with
its feet?

How does a cat make the purring sound? (Do the lips
move? The sides?) How does a cat drink? Do a cat

188 BEGINNERS’ ZOOLOGY

and dog drink exactly the same way? Is the cat’s tongue
rough or smooth? How is the tongue used in getting the
flesh’ off close to the bone? Can a cat clean a bone
entirely of meat?

In what state of development is a newly born kitten?
With what does the cat nourish its young? Name ten
animals of various kinds

whose young are simi-
larly nourished. What
is this class of ani-
fi S'- Me mals called?
Se) ae eR Why does a
cat bend its back

when it is frightened or

anery? Does a cat ora dog eat a greater variety of food ?
Which refuses to eat an animal found dead? Will either
bury food for future use? Which is sometimes trouble-
some on account of digging holesin the garden? Explain
this instinct- Which lived a solitary life when wild ? Which
had a definite haunt, or home? Why are dogs more sociable
than cats? A dog is more devoted to his master. Why?

ae ye >

Ske

Ss ah Abe ZN

Seen UVP KN )
>) PAY
oy 4\\\ \ yy
7): BILL

\

FIG. 336. — JAGUAR, of tropical America.

A cat is more de-

voted to its home,

and will return if
carried away. Why? a
Why does a dog
turn around before
lying down ? (Con- uy ike = ees Set -- ss
sider its original ““""?9sc a
environment. ) FIG. 337-—SKELETON OF Cat.

The Skeleton (Fig. 337).—-Compare the spzxal column
of a cat in form and flexibility with the spinal column of
a fish, a snake, and a bird.

MAMMALS 189

The sku// is joined to the spinal column by two knobs
(or condyls), which fit into sockets in the first vertebra.
Compare the jaws with those of a bird and a reptile.
There is a prominent ridge in the temple to which the
powerful chewing muscles are attached. There is also a
ridge at the back of the head where the muscles which
support the head are attached (Fig. 348).

Count the 7zés. Are there more or fewer than in man?
The breastbone is in a number of parts, joined, like the
vertebrz, by cartilages. Compare it with a bird’s ster-
num; why the difference? The shoulder girdle, by which
the front legs are attached to the
trunk, is hardly to be called a gir-
dle, as the collar bones (clavicles)
are rudimentary. (They often es-
cape notice during dissection, being
hidden by muscles.) The shoulder
blades, the other bones of this gir-
dle, are large, but relatively not so

FIG. 338. — CLAW OF CAT
(1) retracted by ligament, and
broad toward the dorsal edge aS ° (2) drawn down by muscle

ttached to lower tendon.
human shoulder blades. Theclav- t2¢hed f0 lower tendon

icles are tiny because they are useless. Why does the cat
not need as movable a shoulder asa man? The pelvic, or
hip girdle, to which the hind legs are attached, is a rigid
girdle, completed above by the spinal column, to which it
is immovably joined. Thus the powerful hind legs are
joined to the most rigid portion of the trunk.

Mammals.— The cat belongs to the class Mammalia or
mammals. The characteristics of the class are that the
young are not hatched from eggs, but ave born alive, and
nourished with milk (hence have lips), and the skzx zs
covered with hair, The milk glands are situated ventrally.
The position of the class in the animal kingdom was

190 BEGINNERS’ ZOOLOGY

shown when the cow was classified (p. 9). Their care for
the young, their intelligence, and’ their ability to survive
when in competition with other animals, causes the mam-
mals to be considered the highest class in the animal
kingdom.

According to these tests, what class of vertebrates should
rank next to mammals? Compare the heart, the lungs,
the blood, and the parental devotion of these two highest
classes of animals.

FIG. 339.— SKELETON OF LION (cat family).

The first mammals, which were somewhat like small
opossums, appeared millions of years ago, when the world
was inhabited by giant reptiles. These reptiles occupied
the water, the land, and the air, and their great strength
and ferocity would have prevented the mammals from
multiplying (for at first they were small and weak), but
the mammals carried their voung in a pouch until able to
care for themselves, while the reptiles laid eggs and left
them uncared for. The first mammals used reptilian eggs
for food, though they could not contend with the great
reptiles. Because birds and mammals are better parents
than reptiles, they have conquered the earth, and the rep-

MAMMALS IQI

tiles have been forced into subordination, and have become
smaller and timid.

Classification of Mammals. — Which two have the closest
resemblances in the following lists: Horse, cow, deer. Why?
Cat, cow, bear. Why? Monkey, man, sheep. Why? Rat,
monkey, squirrel. Why? Giraffe, leopard, camel. Why?
Walrus, cat, cow. Why?
Check the five mammals
in the following lists that
form a group resembling
one another most closely:
Lion, bear, pig, dog, squir-
rel, cat, camel, tiger, man.
State your reasons. Gi-
raffe, leopard, deer, cow,
rat, camel, hyena, horse,
monkey. State reasons.

Teeth and toes are
the basis for subdividing
the class mammalia into
orders. Although the

breathing, the circulation,
and the internal organs
and processes are
similar in all mammals,
the external organs vary FIG. 341. — WEASEL, in summer; in Canada
greatly because of in winter it is all white but tip of tail.
the varyinmey cen-

vironments of different species. The internal structure
enables us to place animals together which are essentially
alike; e.g. the whale and man are both mammals, since
they resemble in breathing, circulation, and multiplication
of young.’ The external organs guide us in separating the
class into orders) The teeth vary according to the food

192 BEGINNERS’ ZOOLOGY

eaten. The feet vary according to use in obtaining food
or escaping from enemies. This will explain the differ-
ence in the length of legs of lion
and horse, and of the forms of
the teeth in cat and cow. Make
a careful study of the teeth and

the limbs as shown in the figures
FIG. 342.—Foot or Bear 2nd in all specimens accessible

(Plantigrade). Write out the dental formulas as
indicated at the top of page 194. The numerals above the
line show the number of upper teeth, those below the line
show the number of lower teeth, in one half of the jaw.
They are designated as follows: J, incisors; C, canine;
M, molars. Multiplying by two gives the total number.
Which skulls in the chart have the largest canines?
Why? The smallest, or none at all? Why? Compare
the molars of the cow, the hog, and the dog. Explain
their differences. In which skulls are some of the molars
lacking? Rudimentary? Why are the teeth that do not
touch usually much smaller than those that do ?

FIG, 343. ~ POLAR BEAR (U7sus maritimus).

MAMMALS

KEY, OR TABLE, FOR CLASSIFYING MAMMALS
(class Mammaliz) INTO ORDERS

Ai Imperfect Mammals, young hatched or pre-

maturely born

B, Jaws a birdlike beak, egg-laying

Bz Jaws not beaklike, young carried in pouch
A: Perfect Mammals, young not hatched, nor

prematurely born

C Front part of both jaws lack teeth

B, |C, Teeth with sharp points for piercing
shells of insects
with |C, Canines very long, molars suited for

Digits

claws teari ng

C, Canines lacking, incisors very large

Bz
Digits

not
distinct

B
Digits
with
nails

or
hoofs

C! Head large; carnivorous
C, Head small , herbivorous

C, Toes odd number, less than five
C, Toes even number, upper front teeth
lacking, chew the cud
C, Toes even number, upper front teeth
present, not cud-chewers

; All limbs having hands

[: Five toes, nose prolonged into a snout
&
C, Two limbs having hands

ORDERS

Mon! otremes
Marsupials

Eden tates

Lnsect'tvors

Car'nzvors
Rodents

Ceta'ceans
Szre' means

Proboscid' cans
nt yg?

E'quines a

»

&

S

: ES

Ru'minants ( &,

—~

; =)
Swine

Quad rumans
Bu mans

Exercise in Classification. — Copy the following list, and by refers
ence to figures write the name of its order after each mammal : —

Ape (Figs. 405, 406)
Rabbit (Fig. 345)
Dog (Figs. 356, 408)
Hog (Figs. 357, 393)
Bat (Figs. 347, 370)
Cat (Figs. 337, 348)
Armadillo

(Figs 349, 365)

Cow (Figs. 344, 386)
Walrus (Fig. 340)
Monkey

(Figs. 352, 401)
Horse

(Figs. 355, 395)
Ant-eater

(Figs. 354, 364)

Antelope (Fig. 391)
Mole

(Figs. 367, 368)
Beaver

(Figs. 372, 373)
Duckbill (Fig. 359)
Tapir (Fig. 384)
Dolphin (379, 397)

Use chart of skulls and Figs. 381, 382, 395-400 in working out this

exercise.

(194) Chart of Mammalian Skulls (Illustrated Study)

Man’s dental formula is (a4 5,
5

os 2\2
(é 4 = 32.
I 13) 3

In like manner fill out formulas below : —

Cowra skies. sf (M— C—/—)? = 32
Rabbits). sles «.< (W— C—/—)?2= 28
Wralrusi..-cjccre (M— C—/—)*2 = 34
SAC aroseoisis/eseleters)s (W— C— I—)?= 34
Or linomaaanoadoe (7— C—I—)? = 30
Armadillo ..... (17— C—/—)?2= 28
Horse)... <.. .++- (— C—/—)2= 40

FIG. 344.— Skull and front of lower jaw

of Cow.

FIG, 345.— RABBIT.

A, B, incisors; C, molars

Whaie......... (M— C—J—)2= 0
Am. Monkey. . .(1/— C—/—)?= 36
Slothizacceee ee (f— C— /—)2= 18
AMT Eaten nme a (1f— C—/—)2?= 0
DOG wns omnes (7— C—/—)2= 42
LO Peer ty-tearaiate (W— C—I/I—)?=44
SHECDE Seen iier (414— C—J—)2= 32

FIG. 346.— WALRUS (see Fig. 341).

FIG. 347.— BAT.

FIG, 348. —CAT,

Chart of Mammalian Skulls (195)

FIG. 350. — HORSE
(front of jaw).

FIG. 351. —GREENLAND
WHALE.

oe ~= a =) See) TS —
FIG. 353.—SLOTH (Fig. 363). em FIG. 358. — SHEEP.

196 BEGINNERS’ ZOOLOGY

The lowest order of mammals contains only two species,
the duckbill and the porcupine ant-eater, both living in
the Australian re-
gion. Do you judge
that the dzuckbill
of Tasmania (Fig.
359) lives chiefly in

water or on land?
FIG. 359. — DUCKBILL ( Ornithorhynchus paradoxus). Why?

Is it prob-
ably active or slow in movement? It dabbles in mud and
slime for worms and mussels, etc. How is it fitted for
doing this? Which
feet are markedly
webbed? How far
does the web extend ?
The web can be
folded back when not
in use. It lays two
eres, ini a “nest ‘of
grass at the end of a
burrow. Trace re-
semblances and dif-
ferences between this
animal and birds.
The porcupine ant-
cater has numerous
quill-like spines (Fig.
360) interspersed with
its hairs. (Use?) De-

Fic. 360.—SPINY ANT-EATER (chidna acu-
scribe its claws. It leata). View of under surface to show pouch.
(After Haacke.)

has a long prehensile
tongue. It rolls into a ball when attacked. Compare its
jaws with a bird’s bill. It lays one eg

g, which is carried

MAMMALS 197

in a fold of the skin until hatched. Since it is pouched
it could be classed with the pouched mammals (next order),
but it is egg-laying. Suppose the two animals in this
order did not nourish their young with milk after hatching,
would they most resemble mammals, birds, or reptiles ?
Wirite athe name> ol this ozde 2 ==." (See, Table,
p. 193.) Why do you place them in this order (___.)?
See p. 193.) The name of the order comes from two Greek

FIG. 361. — Opossum (Didelphys Virginianus).

words meaning “one opening,’ because the ducts from
the bladder and egg glands unite with the large intestine
and form a cloaca. What other classes of vertebrates
are similar in this ?

Pouched Mammals: — These animals, like the last, are
numerous in the Australian region, but are also found in
South America, thus indicating that a bridge of land once
connected the two regions. The opossum is the only
species which has penetrated to North America (Fig. 361).
Are its jaws slender or short? What kinship is thus sug-
gested? As shown by its grinning, its lips are not well de-

198 BEGINNERS’ ZOOLOGY

veloped. Does this mean a low or a well-developed mam-
mal? Where does it have a thumb? (Fig. 361.) Does
the thumb have a nail? Is the tail hairy or bare? Why?
Do you think it prefers the ground or the trees? State
two reasons for your answer. It hides in a cave or bank
or hollow tree all day, and seeks food at night. Can it run
fast on the ground? It feigns death when captured,
and watches for a

chance for stealthy
escape.

The kangaroo
(Fig. 362), like the
Opossum, gives
birth to imperfectly
developed young.
(Kinship with what
classes is thus in-
dicated ?) After
birth, the young
(aboutthree fourths

FIG. 362.— GIANT KANGAROO,

of an inch long)
are carried in a ventral pouch and suckled for seven or
eight months. They begin to reach down and nibble grass
before leaving the pouch. Compare fore legs with hind
legs, front half of body with hind half. Describe tail.
What is it used for when kangaroo is at rest? In jump-
ing, would it be useful for propelling and also for balanc-
ing the body? Describe hind and fore feet. Order —___.
Why?_____. See key, page 193.

Imperfectly Toothed Mammals. —These animals live
chiefly in South America (sloth, armadillo, giant ant-eater)
and Africa (pangolin). The sloth (Fig. 363) eats leaves.

Its movements are remarkably slow, and a vegetable growth

MAMMALS 199

resembling moss often gives its hair a green colour. (What
advantage?) How many toes has it? How are its nails
suited to its man-
ner of living? Does
it save exertion by
hanging from the
branches of trees
instead of walking

upon them?
Judging from the
figures (363, 364,
365), are the mem-
bers of this order
better suited for at-
tack, active resistance, passive resistance, or concealment
when contend-

FIG, 363. —SLOTH of South America.

ing with other
animals ? he
ant-eater’s claws
(Fig. 364)on the
fore feet seem
to, be ’a hin-
drance in walk-
ing; for what
are they usefui?
Why are its jaws
sq. slénder:,
What is prob-
ably the use of

FIG. 364.— GIANT ANT-EATER of South America.
(See Fig. 354.) Find evidences that the edentates are a the enormous
degenerate order. Describe another ant-eater (Fig. 360). bushy tail? The

nine-banded armadillo (Fig. 365) lives in Mexico and Texas.
It is omnivorous. To escape its enemies, it burrows into

200 BEGINNERS’ ZOOLOGY

the ground with surprising rapidity. If unable to escape
when pursued, its hard, stout tail and head are turned .
under to protect
the lower side of
the body where
thereare noscales.
The three-banded
species (Fig. 366)
lives in Argentina.

FIG. 365.— NINE-BANDED ARMADILLO of Texas
and Mexico. (Dasypus novemcinctus.) It is increas-
ing in numbers; it is very useful, as it digs up and and tail of the two
destroys insects. (See Fig. 347.}

Compare the ears

species; give rea-
sons for differences. Why are the eyes so small? The
claws so large? Ovder_____.. Why?

ale
— } = =>
——— eee =

FIG. 366. — THREE-BANDED ARMADILLO ( Tolypeutes tricinctus) .

Insect Eaters. — The soft interior and crusty covering of
insects makes it unnecessary for animals that prey upon
them to have flat-topped teeth for grinding them to

MAMMALS 201

powder, or long cusps for tearing them to pieces. The
teeth of insect eaters, even the molars (Fig. 368), have
many sharp tubercles, or points, for holding insects and
piercing the crusty outer skeleton and reducing it to bits.
As most insects dig in the ground or fly in the air, we
are not surprised to learn that some insect-eating mam-

FIG. 367. -THE MOLE.

mals (the bats) fly and others (the moles) burrow. Are
the members of this order friends or competitors of man?

FIG. 368. SKELETON OF MOLE. (Shoulder blade is turned upward.)

Why does the mole have very small eyes? Small ears?
Compare the shape of the body of a mole and a rat.
What difference? Why? Compare the front and the hind
legs of a mole. Why are the hind legs so small and
weak? Bearing in mind that the body must be arranged
for digging and using narrow tunnels, study the skeleton

202 BEGINNERS’ ZOOLOGY

(Fig. 368) in respect to the following: Bones of arm
(length and shape), fingers, claws, shoulder bones, breast-
bone (why with ridge like a bird ?), vertebrae (why are the
first two so large?), skull (shape). There are no eye
sockets, but there is a snout gristle ; for the long, sensitive
snout must serve in place of the small and almost useless
eyes hidden deep in the fur. Is the fur sleek or rough?
Why? Close or thin? It serves to keep the mole clean.
The muscles of neck, breast, and shoulders are very
strong. Why? The mole eats earthworms as well as
insects. It injures plants by breaking and drying out
their roots. Experiments show that the Western mole will
eat moist grain, though it prefers insects. If a mole is
caught, repeat the experiment, making a careful record of
the food placed within its reach.

FIG. 369. -SKELETON OF BAT.

As with the mole, the skeletal adaptations of the dat
are most remarkable in the hand. How many fingers?
(Fig. 369.) How many nails on the hand? Use of
nail when at rest? When creeping? (Fig. 369.) In-
stead of feathers, the flying organs are made of a pair
of extended folds of the skin supported by elongated
bones, which form a framework like the ribs of an um-
brella or a fan. How many digits are prolonged? Does

MAMMALS 203

FIG. 370. — VAMPIRE (PAyllostoma spectrum) of South America. X j.

the fold of the skin extend to the hind legs? The tail?
Are the finger bones or the palm bones more prolonged
to form the wing skeleton ?

The skin of the wing is rich in blood vessels and nerves,
and serves, by its sensitiveness to the slightest current of
air, to guide the bat in the thickest darkness. Would you
judge that the bat has sharp sight? Acute hearing?

The moles do not Azbernate; the bats do. Give the
reason for the difference. If bats are aroused out of a
trance-like condition in winter, they may die of starvation.
Why? The mother bat carries the young about with her,
since, unlike birds, she has no nest. How are the young
Mownsned? Orders... Why? 2-25, (Key, ps 193.)

The Gnawing Mammals. —These animals form the most
numerous order of mammals. They /ack canine teeth. In-
ference? The incisors are four in number in all species

Z04 BEGINNERS’ ZOOLOGY

except the rabbits, which have six (see Fig. 345). They
are readily recognized by their /avge incisors. These teeth
grow throughout life, and if they are not constantly worn

FIG. 371.— POUCHED GOPHER (Geomys bursarius) X 3, a large, burrowing
field rat, with cheek pouches for carrying grain.
away by gnawing upon hard food, they become incon-
veniently long, and may prevent closing of the mouth and
cause starvation. The hard enamel is all on the front sur-
face, the dentine in the rear being softer; hence the in-
cisors sharpen themselves by use to a chisel-like edge.

FIG. 372.— Hind foot a, fore foot 4, FIG. 373. — BEAVER.

tail c, of BEAVER.
The molars are set close together and have their upper
surfaces level with each other. The ridges on them run
crosswise so as to form a continuous filelike surface for

MAMMALS 205

reducing the food still finer after it has been gnawed off
(Fig. 345). The lower jaw fits into grooves in place of
sockets. This allows the jaw to work back and forth in-
stead of sidewise. The rabbits and some squirrels have a
hare lip; z.e. the upper lip is split. What advantage is
this in eating? In England the species that burrow are
called rabbits; those that do not are called hares.

Name six enemies of rabbits. Why does a rabbit usually
sit motionless unless approached very close? Do you
usually see one before it dashes off? A rabbit has from
three to five litters of from three to six young each year.
Squirrels have fewer and smaller
litters. Why must the rabbit N
multiply more rapidly than the
squirrel in order to survive?

English rabbits have increased

in. Australia until they are a

plague. Sheep raising is inter- Fic. 374.— Posrrion oF Limss
fered with by the loss of grass. hee
The Australians now ship them to England in cold storage
for food. Rabbits and most rodents lead a watchful,
timid, and alert life. An exception is the porcupine,
which, because of the defence of its barbed quills, is dull
and sluggish.

The common rodents are : —

squirrels beavers pouched gopher ground hog
rabbits muskrats . prairie dog field mouse
rats porcupines _ prairie squirrel

mice guinea pig chipmunk

Which of the above rodents are commercially important ?
Which are injurious to an important degree ? Which have
long tails? Why? Short tails? Why? Longears? Why?

206 BEGINNERS’ ZOOLOGY

Short ears? Why? Which are aquatic ? Which dig or bur-
row? Which are largely nocturnal in habits? Which are
arboreal? Which are protected by coloration? Which
escape by running? By seeking holes?

Economic Importance. — Rabbits and squirrels destroy the
eggs and young of birds. Are rabbits useful? Do they
destroy useful food? The use of beaver and muskrat skins
as furs will probably soon lead to their extinction. Millions
of rabbits’ skins are used annually, the hair being made into

FIG. 375. — FLYING SQUIRREL (Pteromys volucella). x Vy.

felt hats. There are also millions of squirrel skins used
in the fur trade. The hairs of the tail are made into fine
paint brushes. The skins of common rats are used for the
thumbs of kid gloves. Order_____. Why?

Elephants. — Elephants, strange to say, have several
noteworthy resemblances to rodents. Like them, elephants
have no canine teeth; their molar teeth are few, and marked
by transverse ridges and the incisors present are promi-
nently developed (Figs. 376, 377). Instead of four incisors,
however, they have only two, the enormous tusks, for there

are no incisors in the lower jaw. Elephants and rodents

MAMMALS 207

both subsist upon plant food. Both have peacéful disposi-
tions, but one order has found safety and ability to survive
by attaining enormous size and strength; the other (e.g.
rats, squirrels) has found safety in small size. Explain.
Suppose you were
to observe an elephant
for the first time, with-
out knowing any of its
habits. How would
you know that it does
not eat meat? That it
does eat plant food?
That it can defend it-
self? Why would you make the mistake of thinking that
it is very clumsy and stupid? Why is its skin naked?
Thick? Why must its legs be so straight? Why must it
have either a very long neck or a substitute for one?
(Fig. 376.) Are the eyes large or small? The ears? The
brain cavity? What anatomical feature correlates with
the long proboscis? Is the proboscis a new organ not
found in other animals, or is it a specialization of one or
more old ones? Reasons? What senses are especially

FIG. 376.— HEAD OF AFRICAN ISLEPHANT.

active in the proboscis? How is it used in drinking? In
grasping ? What evidence that
it is a development of the
nose? The upper lip?

The tusks are of use in up-

FIG. 377.—Motar ToorH or rooting trees for their foliage
AFRICAN ELEPHANT. : Sry ic
and in digging soft roots for

food. Can the elephant graze? Why,orwhy not? There
is a finger-like projection on the end of the snout which is
useful in delicate manipulations. The feet have pads to
prevent jarring; the nails are short and hardly touch the

ground, Ovder Why ? Key, page 193.

208 BEGINNERS’ ZOOLOGY

Whales, Porpoises, Dolphins. — As the absurd mistake
is sometimes made of confusing zw/a/es with fish, the pupil
may compare them in the following respects: eggs, nour-
ishment of young, fins, skin, eyes, size, breathing, tem-
perature, skeleton (Figs. 209, 379, and 397).

FIG. 378. — HARPOONING GREENLAND WHALE
(see Fig. 351).

Porpoises and dolphins, which are smaller species of
whales, live near the shore and eat fish. Explain the ex-
pression ‘blow like a porpoise.” They do not exceed five
or eight feet in length, while the deep-sea whales are from
thirty to seventy-five feet in length, being by far the largest
animals in the world. The size of the elephant is limited
by the weight that the bones and muscles support and
move. The whale’s size is not so limited.

The whale bears one young (rarely twins) at a time.
The mother carefully attends the young for a long time.
The 6/ubber, or thick layer of fat beneath the skin, serves
to retain heat and to keep the body up to the usual tempera-
ture of mammals in spite of the cold water. It also serves,
along with the zamense lungs, to give lightness to the body.

MAMMALS 209

Why does a whale need large lungs? The ¢az/ of a whale
is horizontal instead
of vertical, that it may

steer upward rapidly
from the depths when

needing to breathe.
The <deeth of some

NE Scie 1 DOnEevaNe whales do not cut the
gum, but are reabsorbed and are replaced by horny plates
of “whalebone,” which act as strainers. Give evidence,
from the flippers, lungs, and other organs, that the whale
is descended from a land mammal (Fig. 397). Compare
the whale with a typical land mammal, as the dog, and

enumerate the specializations of the whale for living in
water. What change took place in the general form of the
body? It is believed that on account of scarcity of food
the land ancestors of the whale, hundreds of thousands of
years ago, took to living upon fish, etc., and, gradually be-
coming swimmers and divers, lost the power of locomotion
on land: ~~ Order 22 | Why.?. ee

Elephants are rapidly becoming extinct because of the
value of their
ivory tusks.
Whales also
furnish valua-
ble products,
but they will

probably exist
much longer. FIG. 380. — MANATEE, or sea cow;; it lives near the shore
Why > and eats seaweed. (Florida to Brazil.)

The manatees and dugongs (sea cows) are a closely re-
lated order living upon water plants, and hence living close
to shore and in the mouths of rivers. Order ___. Why ?__.

210 BEGINNERS’ ZOOLOGY

Hoofed Mammals. — All the animals in this order walk
on the tips of their toes, which have been adapted to this
use by the claws having developed into hoofs. The order
is subdivided into the oda-toed (such as the horse with one
toe and the rhinoceros with three) and the cven-toed (as
the ox with two toes and the pig with four). All the even-
toed forms except the pig and hippopotamus chew the cud
and are given the name of rumznants.

Horse and Man Compared.—— To which finger and toe
on man’s hand and foot does a horse’s foot correspond ?
(Figs. 381, 383, 399.)
Has the horse kneecaps?
Is its heel bone large or
small? Is the fetlock on
toe, instep, or ankle?
Does the part of a horse’s
hind leg that is most elon-
gated correspond to the
thigh, calf, or foot in
man? On the fore leg,
is the elongated part the

upper arm, forearm, or

FIG, 381. — Left leg of man, left hind leg :
of dog and horse; homologous parts hand ? (Figs. 395; 399.)

lettered alike. Does the most elongated

part of the fore foot correspond to the finger, the palm, or
the wrist? (Fig. 882.) On the hind foot is it toe, instep, or
ankle? Is the fore fetlock on the finger, the palm, or the
wtist? (Figs. 382, 385, 399.) Is the hock at the toe,
the instep, the heel, or the knee?

Specializations of the Mammals. — The early mammals,
of which the present marsupials are believed to be typical,
had five toes provided with claws. They were not very
rapid in motion nor dangerous in fight, and probably ate
both animal and vegetable food.

MAMMALS 211

Protohippis}
Pliahippus
FIG. 382. — SKELETONS OF FEET OF MAMMALS.
P, horse; PD, dolphin; £, elephant; A, monkey; 7, tiger; O, aurochs; Miohippus

F, sloth; 47, mole.

Question: Explain how each is adapted to its specialized function.

According to the usual rule, they tended to
increase faster than the food supply, and there _pesofippusy
were continual contests for food. Those whose
claws and teeth were sharper drove the others
from the food, or preyed upon them. Thus the

specialization into the bold flesh eating beasts
wa fe Oroluppus,
of prey and the timid vegetable feeders began. a

FIG. 383. —
Feet of the
ied at length? ‘The insectivora escaped their ancestors of
the horse.

Which of the flesh eaters has already been stud-

enemies and found food by learning to burrow
or fly. The rodents accomplished the same result either by
acquiring great agility in climbing, or by living in holes, or
by running. The proboscidians acquired enormous size
and strength. The hoofed animals found safety in flight.

212 BEGINNERS’ ZOOLOGY

F1G. 384. — TAPIR OF SOUTH AMERICA ( Tapirus americanus). X de.

Questions: How does it resemble an elephant? (Fig. 376.) A horse ? (p. 210.)

Ungulates, as the horse, need no other protection than

their great speed, which is due to lengthening the bones of

IIc. 385.— HORSE, descended from a small
wild species still found in Western Asia.

the legs and rising
upon the very tip of
the largest toe, which,
to support the weight,
developed an_ enor-
mous toe-nail called a
hoof. The cattle, not
having developed such
speed as the horse,
usually have horns
for defence. If a calf

or cow bellows with distress, all the cattle in the neigh-
bourhood rush to the rescue. This unselfish instinct to
help others was an aid to the survival of wild cattle living
in regions infested with beasts of prey. Which of A¢sop’s

fables is based upon this instinct?

The habit of rapid

grazing and the correlated habit of chewing the cud were

also of great value, as it enabled cattle to obtain grass hur-

MAMMALS 213

riedly and to retire to a safe place to chew it. Rudiments of
the upper incisors are present in the jaw of the calf, show-
ing the descent from animals which had a complete set of
teeth. The rudiments are absorbed and the upper jaw of
the cow lacks incisors entirely, as they would be useless
because of the cow’s habit of seizing the grass with her
rough tongue
and cutting it
with the lower
incisors as the
head is jerked /i@'”
forward. This / e

is a more rapid “
way of eating

than by biting.
: FIG. 386. —SKELETON OF Cow. Compare with horse
Which leaves (Fig. 395) as to legs, toes, tail, mane, dewlap, ears, body.

the grass shorter

after grazing, a cow or a horse? Why? Grass is very
slow of digestion, and the ungulates have an alimentary
canal twenty to thirty times the length of the body.
Thorough chewing is necessary for such coarse food, and
the ungulates which chew the cud (ruminants) are able,
by leisurely and thorough chewing, to make the best use
of the woody fibre (cellulose) which is the chief substance
in their food.

Ruminants have four divisions to the stomach. Their
food is first swallowed into the roomy pawnch in which,
as in the crop of a bird, the bulky food is temporarily
stored. It is not digested at all in the paunch, but after
being moistened, portions of it pass successively into the
honeycomb, which forms it into balls to be belched up and
ground by the large molars as the animal lies with eyes
half closed under the shade of a tree. It is then swal-

214 BEGINNERS’ ZOOLOGY

lowed a second time and is acted upon in the third divi-
sion (or manyplies) and the fourth division (or reed ). Next

*
rere
-o.

seas

P_---

Fic. 387. — Food traced
through stomachs of F1G. 388. — Section of cow's stomachs,
cow. (Follow arrows.) Identify each. (See text.)

it passes into the intestine. Why is the paunch the largest
compartment? In the figure do you recognize the paunch
by its size? The honeycomb by its lining? Why is it
round? The last two
of the four divisions
may be known by their
direct connection with
the intestine.

The true gastric juice
is secreted only in the

fourth stomach. Since

the cud or unchewed
food is belched up in
FIG, 389.—OKAPI. This will probably prove

to be the last large mammal to be discovered

by civilized man. It was found in the for- honeycemb,” and since
ests of the Kongo in 1900.

balls from the round

a ball of hair is some-
Questions: It shows affinities (find them) with

giraffe, deer, and zebra. It is a ruminant ungulate times found In the stom-

(explain meaning — see text).

ach of ruminants, some
ignorant people make the absurd mistake of calling the
ball of hair the cud. This ball accumulates in the paunch

MAMMALS 215

because of the friendly custom cows have of combing each
other’s hair with their rough tongues, the hair sometimes

FIG. 390. —AFRICAN CAMEL (Camelus dromedarius).

being swallowed. Explain the saying that if a cow stops
chewing the cud she will die.

Does a cow’s lower jaw move sidewise or
back and forth? Do the ridges on the molars
run sidewise or lengthwise? Is a

EN Aad
) : hs Nn =,
cow’s horn hollow? Does it ——_

have a bony core? (Fig. 344.)

The permanent hol-
low horns of the cow
and the solid decidu-
ous horns of the deer
are typical of the two
kinds of horns pos-
sessed by ruminants.
The prong-horned an-

f FIG. 391. — PRONG-HORNED ANTELOPE
telope (Fig. 391) of (Antelocarpa Americana).

216 BEGINNERS’ ZOOLOGY

the United States, however, is an intermediate form, as its
horns are hollow, but are shed each year. The hollow
horns are a modification of hair. Do solid or hollow
horns branch? Which are possessed by both sexes?
Which are pointed? Which are better suited for fight-
ing? Why would the deer have less need to fight than
the cattle? Deer are polygamous, and the males use their

horns mostly for fighting one another. The sharp hoofs of
deer are also dangerous weapons. The white-tail deer
(probably the same species as the Virginian red deer) is
the most widely distributed of the American deer. It
keeps to the lowlands, while the black-tailed deer prefers
a hilly country. The moose, like the deer, browses on
twigs and leaves. The elk, like cattle, eats grass.

The native sheep of America is the big horn, or Rocky
Mountain sheep (Fig. 392). The belief is false that they

MAMMALS 217

alight upon their horns when jumping down precipices.
They post sentinels and are very wary. There is also a
native goat, a white species, living high on the Rocky
Mountains near the snow. They are rather stupid ani-
mals. The bison once roamed in herds of countless thou-
sands, but, with the exception of a few protected in parks,
it is now extinct. Its shaggy hide was useful to man in
winter, so it has been well-nigh destroyed. For gain man
is led to exterminate elephants, seals, rodents, armadillos,
whales, birds, deer, mussels, lobsters, forests, etc.

(

YW ; i (Wd
Failig AVL. Sy, SY, i
LL (VEEL, ORR -

Le
4}
FIG. 393. — PECCARY (Diécotyles torquatus) of Texas and Mexico. xX 7».

Our only native hog is the peccary, found in Texas (Fig.
393). In contrast with the heavy domestic hog, it is
slender and active. It is fearless, and its great tusks are
dangerous weapons. The swine are the only ungulates
that are not strictly vegetable feeders. The habit of fat-
tening in summer was useful to wild hogs, since snow hid
most of their food in winter. The habit has been pre-
served under domestication. Are the small toes of the
hog useless? Are the ‘‘dew claws” of cattle useless ?
Will they probably become larger or smaller? Ovder ?

218 Illustrated Study

‘Illustrated Study 219

FIG. 400.— CHIMPANZEE. (See Fig. 406.)

Illustrated Study of Vertebrate Skeletons:
Taking man’s skeleton as complete, which of these
seven skeletons is most incomplete ?

Regarding the fish skeleton as the original verte-
brate skeleton, how has it been modified for
(1) walking, (2) walking on two legs, (3) flying ?

Which skeleton is probably a degenerate reversion
to original type ? (p. 209.)

How is the horse specialized for speed ?

2 » Do all have tail vertebrae, or vertebrae beyond
| Sf the hip bones? Does each have shoulder blades ?

Compare (1) fore limbs, (2) hind limbs, (3) jaws
of the seven skeletons. Which has relatively the
FIG. 399. — MAN. shortest jaws? Why? What seems to be the
typical number of ribs ? limbs? digits ?

Does flipper of a dolphin have same bones as arm of a man ?

How many thumbs has a chimpanzee.? Which is more specialized, the foot of a
man or that of a chimpanzee? Is the foot of a man or that of a chimpanzee better
suited for supporting weight? How does its construction fit it for this?

Which has a better hand, a‘man or a chimpanzee? What is the difference in
their arms? Does difference in structure correspond to difference in use ?

Which of the seven skeletons bears the most complex breastbone ?

Which skeleton bears no neck (or cervical) vertebrae ? Which bears only one ?

Are all the classes of vertebrates represented in this chart? (p. 125.)

220 BEGINNERS’ ZOOLOGY

Monkeys, Apes, and Man. —
Study the figures (399, 400);
compare apes and man and ex-
plain each of the differences in
the following list : (1) feet, three
differences; (2) arms; (3) brain
case; (4) jaws; (5) canine
teeth ; (6) backbone; (7) dis-
tance between the eyes.

A hand, wnlike a foot, has
one of the digits, called a
thumb, placed opposite the
other four digits that it may be
used in grasping. Two-handed
man and four-handed apes and
monkeys are usually placed in
one order, the Primates, or

FIG, 402. — LEMUR (Lemur Mone

£03).
claw ?

ea
X yo

Which digit bears @

MAMMALS 221

in two orders (see table, page 193). The lowest members
of this order are the /emurs of the old world. Because of

FIG. 403.— BROAD-NOSED ~ FIG. 404. — NARROW-NOSED
MONKEY. X zs. America. MONKEY. X rx. Old World.

their hands and feet being true grasping organs, they are.
placed among the primates, notwithstanding the long
muzzle and _ expres-
sionless, foxlike face.
(Fig. 402.) Next in
order are the ¢azled
monkeys, While the
tatlless apes are the
highest next to man.

The primates of the
New World are all
monkeys with long
tails and broad noses.
They are found from
Paraguay to Mexico.
The monkeys and
apes of the Old World
have a thin partition
between the nostrils,

and are thus distin- ——
guished from the FIG. 405.— GORILLA. (Size of a man.)

222 BEGINNERS’ ZOOLOGY

monkeys of the New World, which have a ¢hicker par-
tition and have a broader nose. (Figs. 403, 404.) The
monkeys of America all have szx molar teeth in each half
jaw (Fig. 352); the monkeys and apes of the Old World
have thirty-two teeth, which agree both in number and
arrangement with those of man.

Which of the primates figured in this book appear to
have the arm longer than the leg? Which have the
eyes directed forward instead of
sideways, as with cats or dogs?

Nearly all the primates are
forest dwellers,and inhabit warm
countries, where the boughs of
trees are never covered with ice
or snow. Their abzlity tn climb-
ing serves greatly to protect
them from beasts of prey.
Many apes and monkeys are
able to assume the upright posi-

tion in walking, but they touch

FIG. 406. — CHIMPANZEE.

the ground with their knuckles
every few steps to aid in preserving the balance.

The Simzans are the highest family of primates below
man, and include the gorilla, chimpanzee, orang, and gib-
bon. Some of the simians weave together branches in the
treetops to form a rude nest, and all are very affectionate
and devoted to their young. How are apes most readily

distinguished from monkeys? (Figs. 401, 406.)

Fic. 407. — ANATOMY OF RABBIT.

a, incisor teeth;

4, 4', b'’, salivary
glands;

k, jarynx;

1, windpipe;

c, gullet;

d, diaphragm
(possessed only
by mammals) ;

e, stomach;

£; small intestine;

h, h’, \arge intes-
tine;

fs junction of small
and large intes-
tine;

& g’, cxcum, or
blind sac from _*
(corresponds to

the shrunken

MAMMALS

rudimentary
ap-
pendix in man);
carotid arte-

vermiform

My,
ries;
2, heart;
0, aorta;
P, lungs;
g,end of sternum; ,
7, spleen; ,
s, kidney;

7, ureters (from
kidney to blad-
der v).

2. brain of rabbit:

a, olfactory
nerves;

6, cerebrum:

c, midbrain;

a, cerebellum,

Names of limbs

Acutest sense

MAN

FisH TURTLI Drrp

|

ae at ie ea)
|
|
|
|
|

Digits on fore
and hind limb

Locomotion

Kind of food

Care of young

—_——L

St. Bernard German mastiff Pointer Newfoundland
Eskimo 4nglish bloodhound Bulldog Shepherd
Poodle Greyhound Spitz

Dachshund

FIG. 408.— ARTIFICIAL SELECTION. Its effects in causing varieties in one species.
Which of the dogs is specialized for speed? Driving cattle ? Stopping cattle ?
Trailing by scent? Finding game? Drawing vehicles? Going into holes?
House pet ? Cold weather? In Mexico there is a hairless dog specialized for hot
climates. ‘The widely differing environments under various forms of doméstica-
tion cause “sports” which breeders are quick to take advantage of when wishing
to develop new varieties. Professor De Vries by cultivating American evening
primroses in Europe has shown that a sudden change of environment may cause
not only varieties but new species to arise,

>
ed

¥
*

INDEX

Aboral surface, 35.

Acephala, 107.

Adaptation to environment, 148,
185, 201, 205, 207.

Ambulacral, 36.

Ameeba, 10.

Anadon, 98.

Antelope, 215.

Antenne, 68, 87.

Ant-eater, giant, 199; spiny, 196.

Ant-lion, 91,

Ape, 220.

Aptera, 82.

Apteryx, 174.

Aquarium, 17.

Argonaut, paper, 107.

Armadillo, 200.

Arthropoda, 9, 125.

Bat, 202.

Batrachia, 126.
Beaver, 204.

Bedbug, 92, 93.

Bee, bumble, 89; honey, 88.
Beetle, 90, 91.
Big-headed turtle, 149.
Bilateral, 34, 49, 98.
Bill of bird, 151.
Biology defined, 1.
Birds, 150.

Blood, of insects, 78.
Boll weevil, 95, 96.
Boll worm, 95, 96.
Brain, of fish, 118.

Breathing, of bird, 161; of in-
sect, 76.

Bureau of entomology, 95.

Butterfly, 85.

Cabbage butterfly, 84, 86, 87.
Camel, 214.

Candle, 5,

Carbon, dioxide, 24.
Canpaml2aatl7anl23:

Cat, 184.

Caterpillar, tent, 84.

Cell, 6, 7. :
Celom, 46.

Cephalopod, 106.

Chelonia, 143.

Chimpanzee, 219, 221.
Chirping, 66.

Chitin, 77.

Cilia, 14, 20, 101, 103.
Ciliated chamber, 17.

Circulation, in amoeba, 12; in
insect, 77; in fish, 117.

Clam, hardshell, 104; softshell,
104.

Class, 9.

Classification, of animals, 8, 125;
Onis Innis, I/7/e sbnectigy RAE

mammals, 193.
Click-beetle, 91.
Clitellum, 43, 47.

Cloaca, 18.
Clothes moth, 84, 92, 93.
Cockroach, 71.

225

226

Cocoon, 84.

Codling moth, 84, 86, 87, 95.

Ceelenterata, 28.

Coleoptera, 82.

Collecting insects, 72.

Colorado beetle, 90, 91.

Coloration, warning, 84, 146; pro-
tective, 34, 37, 49.

Colours of flowers, 85.

Comparative study, 85, 108, 122,
223; moth and butterfly, 85.

Copper head, 145.

Coral, 31.

Coralline, 31.

Coral snake, 145, 146.

Cricket, 71.

Cross-fertilization, 25.

Cuckoo, 179.

Cuttlefish, 107.

Cyprea, 104.

Cysts, 13.

Darwin, 48, 148.
Devil’s horse, 71.
De Vries, 148, 224.
Digits, 222.
Diptera, 82.
Division of labour, 27, 29.
Dog, 224.

Dolphin, 209.
Doodle bug, 91.
Dorsal, 43.

Dove, 179.
Dragon fly, 93.
Duckbill, 196.

Ear, of bird, 151; of frog, 131;
of fish, 112.

Earthworn, 42.

Echinoderms, 9, 34, 125.

Economic importance of birds,
167; insects, 93; molluscs, 105;

INDEX

rodents, 206.

Ectoderm, 26, 87.

Ectoplasm, 11, 14.

Egg, of insect, 81.

Endolerm, 26, 27, 37.

Kndoplasm, 11, 14.

Energy, in ameba, 12; organic,
2, os-plant, i, o,00

Environment, 148.

Epidermis, of mussel, 98.

Excretion, 12.

Eye, of bird, 150; of frog, 30; of
grasshopper, 67, 79; of fish, 111.

Family, 8.

Fangs, venomous, 145.

Farmers’ bulletins, 95.

Feather, 155.

Fertilization, cross, 85.

Field study, 10, 22, 42, 71, 72, 97,
127, 165, 166, 167, 184.

Fins, 110, 113.

Flagellum, 21, 27.

Flatworm, 49.

Flea, 92, 93.

Flight, of bird, 157, 175; of moth,
84.

Fly, horse, 81; house, 92, 93.

Food, of birds, 177.

Food tube, of bird, 163; of fish,
116; of insect, 76; of mussel,
102.

Foraminifera, 15, 18.

Frog, 128.

Function, 1.

Ganglion, 45.

Gasteropod, 108.

Gastrula, 7.

Genus, 8.

Geographical barriers, 148.
Gila monster, 147.

INDEX 227

Gills, of mussel, 100; of fish, 115.] Lady bug, 91.

Gnawing mammals, 203. Lamellibranch,107.
Gopher, pouched, 204. Lark, meadow, 182; sky, 179.
Gorilla, 221. Larva, 81.
Grantia, 18. Lasso cell, 34.
Grasshopper, 70. Leg, of bird, 152; of horse, 210;
Gypsy moth, 95. of insect, 74.
‘| Lemur, 220.
Hands, defined, 220. Lepidoptera, 82, 87.
Heart, insect, 77. Louse, 92, 93.
Hemiptera, 82. Lungs, of bird, 165.

Heredity, 147, 153.

Hessian fly, 95. Madreporite, 35.

Horned toad, 140. Mammal, 184; classified, 193;
House fly, 92, 93. defined, 189.

Human species, 220. Manatee, 209
ae a Mandibles, 68, 74.
y rant Wee Mantis, praying, 3.
Hydroid, 28, 29, 30. Mantle, 99
Hymenoptera, 82. Meals 68, 74.
Hypostome, 23. ae

Maxillary palpi, 68, 74.

Ichneumon fly, 89. May beetle, 90, 91.

Imago, 81. May fly, 83.
Infusoria, 16. Measuring worm, 81, 84.
Medusa, 31.

Inorganic, 1.

Insecticides, 95.

Insects, 73, 75; biting, 82; classi-
fied, 82; sucking; 82. 82.

Instinct, 80, 121. Metazoan, Ly
Migration of birds, 171, 173.

Mimicry, 146.

Mesoglea, 26.
Metamorphosis of insect, 80, 81,

Jacana, Mexican, 178.

Jay, blue, 181. Moccasin, 145.

Jelly fish, 29, 30. Mole, 201.
Mollusc, 9, 97, 125.

Kangaroo, 198. Moulting, 69, 174.

Kidneys, of fish, 117; of insects,| Monkey, 220.

76; of mussel, 102; of worm, 45. | Morula, 7.
Mosquito, 92, 93, 96.

Labial palpi, 68, 74, 101. Moth, 83.
Labium, 68, 74. Mother-of-pearl, 99.
Labrum, 68, 74. Mussel, 96, 103.

228

Nautilus, chambered, 107.

Nectar, 8.

Nephridium, 45.

Neryous system, of bee, 78; of
mussel, 102.

Nest building, 166, 182.

Neuroptera, 82.

Nostril, of bird, 151; of fish, 112.

Nucleolus, 6.

Nucleus, 6, 11, 14.

Octopus, 106.
Okapi, 214.
Omnivorous, 47.
One-celled animals, 7.
Opossum, 197.
Oral surface, 35.
Orang, 227.
Order, 9.

Organ, 1].
Organism, 1.
Orthoptera, 82.
Osculum, 18.
Ovary, 25, 37, 117.
* Oviduct, 46.
Oxidation, 3, 4, 5.
Oxygen, 4, 5.
Oyster, 104.

Paramecium, 13.
Parasites, 49, 93.
Partridge, 178.
Pearls, 105.
Peccary, 217.
Perch, 109, 110, 123.
Pests, insect, 93.
Pheasant, 174.
Plastron, 141.
Pollen, 85.

Pollen basket, 88.
Polyp, 9, 22, 125.

Portuguese man-o'-war, 28.

INDEX

Potato bug, 90.

Primates, 220.

Proboscis, of butterfly, 83, 87:
elephant, 207.

Prolegs, 84, 87.

Protection of birds, 171.

Protective resemblance, 34, 146.

Protoplasm, 6, 11.

Protozoa, 7, 9, 11, 125.

Pseudoneuroptera, 82.

Pseudopod, 11.

Quill, 156.

Rabbit, 205, 223.

Radial symmetry, 34, 125.

Rattlesnake, 145.

Rectum, 134.

Regeneration of lost parts, 37.

Reproduction, 12, 15, 20, 25, 37,
46, 120.

Reptiles, 139.

Rhizopoda, 16.

Road runner, 169.

Robin, 183.

Rotifer, 49.

Round worm, 49.

Ruminant, 213.

Salamander, 134, 138, 139.

Sandworm, 49.

San José scale, 95.

Scab in sheep, 95.

Scales, of bird,
moth, 89.

Scallops, 104.

Scarab, 90, 91.

Sea anemone, 33.

Sea fan, 32.

Sea horse, 124.

Sea urchin, 38.

Senses of insects, 76.

161; 110;

fish,

INDEX

Sete, 43, 48.

Sexual selection, 174.

Shark, 121.

Silkworm, 84, 86, 95.

Silver scale, 83.

Siphon, 101.

Siphonoptera, 82.

Skeleton, of bird, 152; cat, 188;
frog, 131; of fish, 113: chart of,
218.

Skull, mammalian, 194.

Slipper animalcule, 13.

Sloth, 199,

Slug, 105.

Snail, 105.

Soil, 48.

Sparrow, 182; English, 170.

Specialization, 20, 27, 66, 210.

Species, 8.

Spermary, 25, 27.

Spicule, 18..

Spider, 94.

Spiracle, 77, 87.

Sponges, 17, 125; glass, 19; horny,
19; limy, 19.

Sports, 148, 224.

Squash bug, 93, 95.

Squid, 106.

Stickleback, 119.

Struggle to live, 147.

Study, comparative, 82, 149, 223.

Sun energy, 2.

Sunlight, 2.

Survival of fittest, 147.

Tadpole, 126, 134.

Tapeworm, 49.
Tarantula, 94.

Teeth, of frog, 130.
Terrapin, 143, 144.
Toad, 137.

Tortoise, 140, 143, 144.
Trap-door spider, 94.
Tube feet, 35.

Tumble bug, 90, 91.
Turtle, 140, 143, 144.

Umbo, 98.
Ungulate, 212.

Vacuole, 11, 12, 14.
Vampire, 203.
Variation, 147.

Variety, 8.

Venomous snakes, 143.
Vent, 42.

Ventral, 43.

Vermes, 9, 125.
Vertebrates, 9, 125.
Vertebrate skeletons, 218.
Viscera, of bird, 163.

Warning sound, 147.
Wasps, digging, 89.
Weevil, 90, 91, 96.
Whale, 208.

Wings, of grasshopper, 67;

bird, 153, 158.
Woodpecker, 180.
Worms, 42.

Zoology defined, 1.
Zoophytes, 33.

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