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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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