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Pio. ESS: O NS

IN

LOOLOGY

BY
VERNON L. KELLOGG

Professor in Leland Stanford Junior University

 

NEW YORK
HENRY HOLT AND COMPANY
1903
Copyright, 1903,
BY
MENRY HOLT AND COMPANY

ROBERT DRUMMOND, PRINTER, NEW YORK.
PREFACE

Tuis book, an introduction to the study of animals and their
life, is intended for use in grammar schools and in those high
schools which are not equipped with laboratories or which do not
care to undertake the study of zoology by having the pupil dis-
sect a series of types or examples. For high schools prepared
to take up this college method of zoological study the author’s
Elementary Zoology is intended. In preparing a text-book for
the guidance of teachers and pupils in high schools without
laboratory equipment and in grammar schools and classes of
younger pupils, the author has believed it better to write a new
book, rather than to shorten and ‘‘ simplify ’’ the text intended
for larger high schools and older pupils. He has believed it
better to make the life-history and habits of familiar animals
the basis for a beginning study of zoology by young pupils rather
than to make the study of structure and classification such a
basis. But this is not a reading book, or nature-study story
book. It is a guide and outline for constant, specific personal
work in observation, and answering questions by means of this
observation, on the part of the pupils, and only such telling of
facts is included as seems necessary to make significant and
coherent and related the self-made discoveries of the pupils.

The actual method of use of the book will be obvious to any
teacher into whose hands it may fall. The succession of chap-
ters is one that seems natural and useful to the author; for any
teacher it will be, of course, a simple matter to modify and re-
arrange the course of work as outlined. In fact the opportu-
nities for obtaining material for study offered by the situation of
the school, as, for example, whether on the seashore or in the
interior near a lake or river, or on the dry plains, and the rela-
tion of the school terms to the seasons of the year, and other

special and varying conditions, will dictate in large measure the
Vv
vi PREFACE

teacher’s actual procedure. The numbered parts of the book
indicate the classification of the study of animals into particular
phases or kinds of study rather than a definite linear arrange-
ment or sequence of this study. The lessons or subjects of
Part IV, for example, should be interpolated wherever the
teacher finds fittest opportunity in connection with the study of
special animals or groups of animals. Chapters VI, VII, and
VIII of Part II have to do with that part of the study of animals
which, as usually treated, demands the facilities of equipped
laboratories. As here treated no laboratory work is required,
but these chapters have been arranged to call for the continuous
and thoughtful ‘‘seeing why’’ of facts mostly already familiar
to the pupil. In this way the author believes that what little
knowledge of the internal anatomy of animals young people can
get will have a maximum of worth,

The author wishes to express his special obligations to Dr.
O. P. Jenkins, professor of physiology in Stanford University,
for the first draft of Chapters VI, VII, and VIII of Part II, and
to thank Mrs. D.S. Jordan and Miss Isabel McCracken for their
critical reading of the MS. and proof-sheets, respectively, of the
book. For aid and courtesy in the matter of illustrations the
author’s thanks are due Miss Mary Wellman, who made all the
drawings for figures whose origin is not elsewhere specifically
indicated, and to Professors M. V. Slingerland of Cornell Uni-
versity and L. L. Dyche of Kansas State University, Dr. L. O.
Howard, U. S. Entomologist, Mr. Geo. O. Mitchell of San
Francisco, Mrs. Elizabeth Grinnell of Pasadena, California, Mr.
J. O. Snyder, Stanford University, Mr. Frank Chapman, editor
of ‘‘Bird-Lore,’’ Mr. G. O. Shields, editor of ‘‘ Recreation,”’
Mr. Geo. A. Clark, secretary U.S. Fur Seal Commission, the
American Society of Civil Engineers, Cassell & Co., the Out
West Publishing Co., Camera Craft, ‘‘ The Condor,’’ and the
Whitaker and Ray Co. of San Francisco. ‘The illustrations
got from these various sources are all specifically indicated in
connection with their special use.

VERNON LYMAN KELLOGG,

STANFORD UNIVERSITY, May, 1903.
CONTENTS

PART |

THE LIFE HISTORY OF ANIMALS

I—MOSQUITOES, SILKWORMS, AND DRAGON.-FLIES

Animals not fully developed at birth, 1.—Mosquitoes, 2,—The eggs and
hatching, 2.—The wrigglers or larve, 4.—The pupz, 6.—The winged or
imago stage, 7.—Distribution of mosquitoes, 8,—Silkworms, 9.—How to
get silkworm eggs, 9..-The eggs and hatching, 11.—The larve or silk-
worms, 11.—The cocoon and pupa, 15.—The moths and egg-laying, 17.—
Other moths and butterflies, 20.—Dyragon-flies. 21.—The adults, 21.—Egg-
laying, 23.—Nymphs, 23.—The transformation to winged stage, 25.

Il.—TOADS AND TADPOLES

The eggs and hatching, 27.The tadpoles, 28.—Toads and frogs 31.

Ill. A BIRD’S NEST AND OTHER ANIMAL HOMES

A bird’s nest, 34.—Homes of insects and spiders, 36.—Homes of the
backboned animals, 42.

PART II

THE PARTS OF ANIMALS AND HOW THEY ARE USED

IV. THE GRASSHOPPER AND THE SNAIL

An animal’s body composed of parts, 47.—The grasshopper or locust, 48.
—The pond snail, 52.
vii
vill CONTENTS

V. THE SUNFISH AND THE SPARROW
The sunfish, 54.—The English sparrow, 58.
VI. THE MOTIONS OF ANIMALS AND THE SKELETON AND
MUSCLES
Motion and locomotion, 64.—Muscles and skeleton, 68.
VII. HOW ANIMALS CHANGE FOOD AND AIR INTO FLESH
AND ENERGY
Necessity of oxygen and food, 77.—How animals breathe, 79.—How
animals obtain and digest food, 86.—How the blood circulates, 93.
VIII. HOW ANIMALS KNOW THINGS AND CONTROL THEIR
MOTIONS

The central nervous system, 100.—The special senses and their organs,
103.

PART Il
VARIOUS KINDS OF ANIMALS AND THEIR LIFE

IX. THE AMCEBA, HYDRA, AND OTHER SIMPLE ANIMALS

Amceba, 114.—Other one-celled animals, 116.— Ocean Protozoa, 119,—
Hydra, 122.

X. OCEAN ANIMALS: SPONGES, SEA-ANEMONES, JELLY FISHES,
CORALS, STARFISHES, OYSTERS, CLAMS, AND SEA-SHELLS

Sponges, 125.—Sea-anemones and corals, 126 —Jellyfishes, 131.—Star-
fishes and sea-urchins, 134.—Oysters, clams, and sea-shells, 139.

XI. WORMS, CRAYFISHES, CENTIPEDS, AND OTHER SMALL
LAND ANIMALS

Earthworms and leeches, 144.—Vinegar-eels, hair-worms, and trichine,
146,—The crayfish, 149.—Lobsters and crabs, 154.—Pill-bugs and water-
fleas, 157-—Thousand-legged worms and centipeds, 159.

XI. INSECTS

Pond and brook insects, 163.—Moths and butterflies, 171.—Aphids, ants,
and aphis-lions, 174.—Cicadas, katydids, crickets, and the sounds of in-
sects, 179.—The solitary bees and digger-wasps, 182.
1x

XITI.—SPIDERS AND THEIR WEB-MAKING

Collecting spiders, 190.—The make-up of the spider body, 192.—The
hunting spiders, 193.—The web-weaving spiders, 196.—Life-history of
spiders, 207.

XIV.—FISHES, BATRACHIANS, AND REPTILES

The fishes, 210.—The batrachians, 215.—The reptiles, 219.

XV.—BIRDS

The English sparrow, 230.—The beginning study of birds, 231.-—Classi-
fication and identification, 233.—Birds and the seasons, 238.—Structure
and habit, 244.—Feeding habits, economics, and protection of birds, 250.

XVI.—MAMMALS

The house mouse, 254.—Classification, 256.—The opossums and kanga-
roos (Marsupialia), 256.—The rodents and gnawers (Glires), 258.—The
shrews and moles (Insectivora), 261.—The bats (Chiroptera), 261.—The
dolphins, porpoises, and whales (Cete), 262.—The hoofed mammals (Ungu-
lata), 263.—The carnivorous mammals (Fere), 266.—The man-like mam-
mals (Primates), 269.

PART IV

ANIMALS IN RELATION TO EACH OTHER, AND TO
THE OUTSIDE WORLD

XVII.—THE STRUGGLE FOR FOOD AND ROOM, AND SPECIAL
MEANS FOR FOOD-GETTING AND PROTECTION

The multiplication of animals, 273.—The struggle to live, 274.—Se-
lection by nature, 275.—Special means to get food, 275.—Special means
for protection, 277.—Examples to be looked for by pupils, 279.

XVIII.—THE COLORS AND MARKINGS OF ANIMALS, AND
THEIR USES

The scales and colors of butterflies’ wings, 281.—Colors of other animals,
285.—Uses of color, 285.—Special protective resemblance, 287.— Warning
colors, 288.—Mimicry, 291.—Other uses of color and marking not yet
understood, 291.

XIX.—ANIMAL PARASITES

Degeneration of parasites, 293.—Internal parasites, 295.—Parasitic in-

sects, 297.
x CONTENTS

XX. THE HONEY-BEE AND OTHER SOCIAL ANIMALS

The life of a honey-bee, 302.—Ants, 309.—Wasps and bumble-bees, 315.
—Other social animals, 318.

XXIL—HOW ANIMALS ARE DISTRIBUTED OVER THE WORLD

Animals limited to particular regions, 319.—Barriers, 320.— How animals
spread, 321.—Map showing the distribution of animals, 322.

APPENDICES

APPENDIX I.—NOTE-BOOKS, DRAWINGS, AND REFERENCE
BOOKS, 325.

APPENDIX II.—REARING ANIMALS, AND MAKING COLLEC.-
TIONS

Live-cages and aquaria, 329.—Making collections, 333.—Collecting and
preserving insects, 335.—Collecting and preserving birds, 338.—Collecting
and preserving mammals, 342.—Collecting and preserving other animals, 344.

APPENDIN III.—CLASSIFICATION OF ANIMALS, 345.
PART |
THE LIFE-HISTORY OF ANIMALS

CHAPTER I

MOSQUITOES, SILKWORMS, AND DRAGON-
FLIES

Animals not fully developed at birth.—lIt is fa-
miliar knowledge of us all that any animal when just
born differs from its parents more or less. The downy
little chick, just from the egg, is very different from the
old hen or crowing rooster; a kitten with its unopened
eyes and helpless little legs differs plainly from the strong,
large mother cat. These differences are due to the fact
that the chick and the kitten are not fully developed, or,
as we say, not full grown. And such differences are even
greater in some other animals, as, for example, butterflies
and frogs. Butterflies’ eggs hatch, not into butterflies,
but into worm-like caterpillars, while newly hatched
frogs are not frog-like at all, but are the little, long-tailed,
fish-like creatures we call tadpoles. But the caterpillar
will develop into, or grow up to be, a butterfly, just like
the splendid one which laid the egg from which it hatched,
and each tadpole will grow to be a frog. What is true
of cats and chickens, frogs and butterflies, is true of all
other animals; that is, every animal has to go through
more or less growth and development in order to become
2 FIRST LESSONS IN ZOOLOGY

like its parent. The story of an animal's birth, its growth
and gradual change or development into a mature or
adult individual, is called its life-story or /¢/e-Arstory.

In the following studics of insect life-histories the
growth and development of the insects from hatching to
maturity can be readily observed in the schoolroom.
The particular insects chosen are selected because they
can be easily obtained and reared indoors, and because
they present especially interesting changes in their de-
velopment. But other insect life-histories may be ob-
served, either completely or in part, if it is so desired.
Various caterpillars and chrysalids can be kept alive and
watched as they develop into moths or butterflies, and
various grubs that live in the ground can be kept until
they become beetles. Flesh-flies may be allowed to lay
their eggs on decaying meat, and the hatching of the
maggots, their change into brown seed-like pupa, and
the final emergence from these of the blue and green flies
all carefully noted.

MOSQUITOES
The eggs and hatching.—Mosquitoes’ eggs are usually
laid in small blackish masses, which float on the surface
of water. (In the case of some species the eggs are laid
y.) These

sooty egg-masses are composed of a single layer of slen-

in groups of only a few, or even deposited sing]

der elongate eggs standing on end and loosely fastened
together to form a narrow, irregular, little raft, slightly
concave on the upper surface, and wholly unsinkable.
They are to be found on small pools of standing water,
or in watcring-troughs or exposed barrels—wherever in-
deed there is quiet or stagnant water. These ege-
masses should be brought into the schoolroom and kept
in glass tumblers, with some of the water on which they

are found floating (fig. 1). Examine an egg-mass with
D DRAGON-FLIES 3

a hand lens to note the arrangement and appearance
of the eggs. How many are there in the mass?
The eggs should be kept under pretty constant obser-

 

 

 

 

Fic. 1.—The mosquito, Cu/ex sp.; showing eggs (on surface of water),
larvee (long and slender, in water), pupa (large-headed, at surface), and
adult (in air). (From living specimens. )

vation, for hatching is likely to take place soon after
they are brought into the schoolroom. Ordinarily they
hatch in from twelve to twenty-four hours after they are
laid. They may, of course, hatch at night. But if the
hatching occurs during the day it can be easily observed.
4 FIRST LESSONS IN ZOOLOGY

From which end of the egg does the young mosquito
emerge? It may not be easy to find the egg-masses on
the pools ; in that case the wrigglers or larvae (described
in the next paragraph) should be sought for and brought
into the schoolroom in tumblers or jars containing water
taken from the pool in which they are found. The life-
history can be studied from this point on. The tumblers
must not be kept in places too cool or dark, or the young
mosquitoes will develop abnormally slowly.

The ‘‘wrigglers’’? or larvea.—The newly hatched
mosquito bears no resemblance to the familiar winged fly
which we call by that name. In this first stage of its life,
or second stage, if we call the egg stage the first, it is
familiarly known as a ‘“wriggler,” but is called /arva by
naturalists. The active young stage of any insect which
differs markedly from the fully developed or mature one
is called the larval stage.

The larva swim actively about. By what means do
they swim? If they cease swimming do they sink deeper
in the water or rise to the surface? Is the body of the
larva more or less dense than the water? that is, is it
heavier or lighter than water ? Note that some of
them hang quietly from the surface, and that each one
comes occasionally to the surface and rests there for
a while to breathe. Every animal has to breathe; that
is, to take up oxygen from the air and to give off from its
body carbon dioxide (CO,). There is always some air
mixed with or dissolved in water, and some aquatic ani-
mals—fishes for example—have special structures called
gills which enable them to take up this dissolved oxygen,
and thus to breathe under water. But the mosquito larva
has no gills, and therefore has to come occasionally to
the surface to breathe.

Examine with a hand lens one of the larvae ina watch-
glass of water. Distinguish the head end of the body ;
MUSYUIIUES, SILAWURKMS, AND DRAGON-FLIES 5

note the eyes (two small black spots), the feelers, or
antenne, and a pair of tufts or brushes of hair on the head
which vibrate rapidly and constantly. These brushes by
their vibration create currents in the water setting toward
the mouth, which lies between them, and thus bring food
to it. This food consists of any tiny animalcules and
microscopic bits of organic matter in the water. Are
there any legs or wings? Examine the _ posterior
end of the body and note its division into two parts—
one the end of the hind body or abdomen, the other a
breathing-tube projecting from the next to last body-
ring. Make a drawing of the larva, showing and naming
all these parts.

Observe again the larve in the jar. When they hang
from the surface note that only the tip of the breathing-
tube reaches it. Note the vibration of the mouth-brushes.
The larvz feed busily for most of the time. If they sink
in the water when they stop “ wriggling,” i.e., swimming,
how is it that they can rest quietly at the surface? For
this reason: the tip of the stem-like breathing-tube pro-
jects slightly above the surface when the wriggler comes
up to breathe, so that the expanded edges of its mouth
are caught by the tense surface film and the wriggler’s
body being but slightly heavier than water, is thus sup-
ported or suspended by the film. It is easier to prove
the existence of this film than to explain it. If you care-
fully lay a clean needle on the surface of the water it
will not sink, although much denser, i.e., heavier than
water, but will be supported by the surface film. If you
fill a tumbler to its brim you can still add more water
carefully and so heap it up above the level of the brim.
This is because the surface film extending over the water
from edge to edge holds it in place. If you dip your
finger in and then lift it up the water does not all run off,
but a large drop will remain hanging to your finger.
6 FIRST LESSONS IN ZOOLOGY

The tense surface film holds the little mass together in
the form of a drop. The mosquito larva takes advantage
of the surface film and is able to keep itself at the surface
when breathing by hanging from it. Water-striders and
the numerous little flies which run quickly and safely
about on the surface of the water are supported by the
film. Their feet make little dents or depressions on the
water’s surface, but do not break through.

It is probable that the movements of the feeding-brushes
also help to keep the wriggler at the surface, as the
wrigglers seem to be able to balance themselves, i.e.,
keep from sinking, in the water by these movements.

Observing the larve or ‘“‘wrigglers ’’ from day to day
it will be noted that they increase in size, that is, are
growing. They breathe and feed and swim and grow.
And some keenly observant pupil may see that they
occasionally cast their skin, or moult. That the larve
do moult one or more times is certain; how many times,
however, has not yet been found out.

The pupz.—After several days—just how many each
pupil should determine for himself—the long slender
larve enter upon another stage in the mosquito’s life
called the pupal stage, and the young mosquitoes are now
called pupe. In this stage the head end is large and
bulbous, the hind body is usually curled underneath the
head, and the creature spends most of its time floating at
the surface. It can swim, and does so when disturbed,
by a peculiar straightening and folding of its body.
When it stops swimming what happens to it? In what
way must the pupa differ from the larva in its relation to
the density of water ?

Examine with a hand lens one of the pup in a watch-
glass of water. Note the two tubes or horns which
project upwards from the back or dorsal part of the
bulbous head end of the body, and the pair of flaps at
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 7

its posterior tip. What are the dorsal tubes for? With
what do they correspond in the larve? The pupa takes
no food at all, and usually floats quietly at the surface.
Why then does it swim at all? What is the use of the
flaps at the end of the body? Note the indications of
legs and wings folded on the under side of the head
end. Make a drawing showing and naming these
parts.

In two or three days the pupa suddenly changes into
the full-fledged winged mosquito. That is, the cuticle or
outer skin wall of the body splits along the middle line of
the back, and the winged mosquito emerges through this
opening. What part of the body appears first? What
parts next? While the mosquito is emerging the pupal
skin serves as a raft upon which the soft-bodied damp
insect is partly supported until its wings and legs are un-
folded and dried and hardened, and it is ready to fly
away. Sometimes the body rests simply on the surface
of the water, being supported by the surface film. This
transformation of pupa into fully developed mosquito can
be readily observed, and each pupil should see it.

The winged or imago stage.—The mosquito is now
full-grown and fully developed ; and in this fully devel-
oped stage it is called an zmago, to distinguish it from
larva and pupa. It is of course the same insect, a mos-
quito all the time, but we commonly apply that name
only to the winged stage or imago. A few of the winged
mosquitoes should be killed in a ‘‘killing-bottle ’’ (see
page 335), and examined under a hand lens. Two kinds
may be distinguished; one with many long hairs on their
feelers or antenne, the other with fewer and much
shorter hairs ; the latter are females, the ones with bushy
antenne males. These antenne are the mosquito’s
organs of hearing. How many wings has the mosquito ?
How many pairs of legs? Can you find behind the
8 FIRST LESSONS IN ZOOLOGY

wings a pair of delicate little knobbed processes projecting
from the body? These are
called balancers and they aid
the mosquito in directing its
flight. Note the long, piercing
and sucking beak (fig. 2) by
means of which the mosquito
gets its food, which is either the
blood of animals or the sap of
plants. The male mosquitoes
never (or very rarely) suck
blood. On each side of the
beak, and arising at its base, is

 

Fic. 2,—Deak of female mosquito 4 pair of feelers or palpi, pre-
dissected to show the piercing sumably organs for smelling
needle-like parts, and_ their : ;
sheath; mx.p, the maxillary and tasting, or which at least
palpi, or feelers of the mouth. gid in determining the charac-

ter of the food. These palpi are as long as the beak in

the males, but less than half as long in the females.

What are the large black spots on the head? Make a

drawing of a mosquito, showing and naming these parts.
If some of the mosquitoes are kept alive in jars filled

with water and covered with netting the females may
perhaps lay eggs on the surface of the water. But it is not
at all certain that they will ; indeed, they seem to lay eggs
only rarely when thus kept in confinement. Ifa slice of
banana be put in the jar the mosquitoes may be seen to
suck the sap from it, and they may be kept alive for many
days if given fresh banana every three or four days. If
the egg-laying occurs, the life-history of our mosquitoes
is completed. A new cycle is about to begin.
Distribution of mosquitoes.-—Mosquitocs are distrib-
uted all over the world, being found in cnormous numbers
in arctic regions and on high mountain ranges as well as
in the tropics, and in swamps and marshy valleys. About
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 9

three hundred and fifty species, or different kinds, of mos-
quitoes are known, nearly fifty of which are found in North
America. Besides the irritation caused by their “‘bite,’’
i.e., piercing with the sucking beak, it has been proved
that mosquitoes are the conveyers and distributors of the
germ of malarial fever. Only certain kinds of mosquitoes,
however, are malaria-carriers. These all belong to the
genus Anopheles ; most of them may be distinguished
by the possession of spotted wings, while the innocuous
kinds have the wings clear. There are a few innocuous
or non-malarial kinds with spotted wings, however, but
no malaria-carrying kinds with wholly clear wings. Other
kinds of mosquitoes are almost certainly the distributors of
the germs of yellow fever, and the same kinds convey a
terrible tropical disease called elephantiasis.

The most effective remedy against mosquitoes is to
pour a little kerosene on the surface of the pool in which
the larvae and pupe live. The kerosene will spread out
and form a thin, oily film over the surface of the water,
and no winged mosquito will be able to emerge alive
through this film, contact with kerosene being fatal to
almost all insects, and especially so just after a moult.

For a full and excellent account of the life of mosquitoes
see ‘“‘ Mosquitoes,” by Dr. L.O. Howard. (See page 327 for
list of reference books with publishers’ names and price.)

SILKWORMS

How to get silkworm eggs.—Live eggs of the silk-
worm moth, Bombyx mort, are regularly sold by dealers
in Japan,* and sometimes can be got in curiosity shops
in this country. They may also be obtained wherever
there is a silkworm-rearing establishment in this

* Silkworm eggs can be obtained from the Kioto Agricultural School,
Kioto, Japan, or from the Nishigahara Agricultural Experimental Station,
Silk Culture Dep’t, Tokio, Japan, or from Mr. S. I. Kuwana, Buzen, Kiu-
shiu, Japan.
10 FIRST LESSONS IN ZOOLOGY

country, though unfortunately there are but few now.
The author will be glad to send* a few eggs, say
twenty-five, once to any teacher who will defray the
cost of postage. From the first lot of eggs moths
may be raised and new eggs obtained, and a gen-
eration thus be reared each year. There are four kinds
or races of silkworms, one of which, known as annuals,
produces but one generation a year, the second kind,
called bivoltins, produces two, the third, the trivoitins,
produces three, while the fourth, found in India, produces
six or seven generations each year. The eggs which the
author can furnish are those of the annual race, and will
naturally hatch in the Middle and Eastern States from
April 15 to May 1. By keeping them at a temperature
of 40° F., or below, the hatching may be postponed as long
as desired. Under no circumstances should it be allowed to
take place before the first mulberry or osage orange-leaves
appear in the spring. If it is more convenient to rear the
silkworms in the fall, the eggs may be kept in some re-
frigerator or cold-storage room through the summer. But
the natural hatching-time will be found to coincide fairly
with the leafing of the mulberry and osage-orange trees,
and no special care in keeping will be necessary. As the
silkworms will feed on no other than mulberry or osage-
orange leaves, a supply of these must be available, or
some other moth chosen for this life-history study. _How-
ever, both these trees are spread over the whole country,
and one or the other is to be found in nearly every locality.

The advantage of using the mulberry silkworm moth for
this life-history study lies in the « domesticity ” of the in-
sect ; the worms have no tendency to crawl away but
will remain quietly in open shallow trays as long as food
is provided them, and the moths, although winged, do not

* Address V. L. Kellogg, Stanford University, California.
cents in stamps for postage.

Send five
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES II

fly. The larve are not hairy and all their markings,
their changes during growth, and their behavior can be
fully observed. And finally, the moths are obliging
enough to lay their eggs on whatever is provided them,
and do not insist on flying away into the fields ; thus the
process of egg-laying can be observed and the age of the
eggs be exactly known.

The eggs and hatching.—The eggs of the silkworm
moth are nearly spherical, a little flattened, and about the
size of a mustard-seed. When first deposited they are
yellow, but soon become grayish or slate-colored and in-
dented on top. Each female moth lays about 300 eggs.
These remain unchanged in appearance, after the first
change from yellow to gray, until about the hatching
time, when they become paler. The tiny worm or larva
inside, for the silk ““worm”’ is of course simply the larva
or first young stage of the silkworm moth, gnaws its way
through the thin egg-shell and crawls out ready to begin
feeding. Some newly hatched larve of moths and butter-
flies have the curious habit of eating the egg-shells as soon
as they issue from them. Do the young silkworms do this ?

The larva, i.e., ‘‘silkworms’’ (figs. 3 and 4).—As soon
as the eggs begin to hatch fresh leaves of the mulberry or
osage orange must be supplied to the young larve. These
leaves must not be wet, for the tiny silkworms seem to
have rather delicate stomachs which object to cold damp
food. They should be cut into pieces, the bits being evenly
spread about in the shallow tray or box-cover in which
the worms are to live. Watch the young larve crawl
and feed. Note that they bite out little crescents and
semicircles in the edges of the leaves. Does the silk-
worm have any particular way of moving its head when
biting off bits of leaf-tissue? Examine one of the tiny
worms with a hand lens. Note that its body is composed
of aseries of segments or rings. How many pairs of legs
12 FIRST LESSONS IN ZOOLOGY

are there and on what body-rings are they? Note the
scattered long hairs sparsely covering the body. Can

 

Fic. 3.—Silkworms feeding on mulberry leaves. (From life.)

you see the jaws and eyes on the head? Make a draw-
ing of a worm as seen from the side.

Silkworms will eat a surprisingly large amount of
food, and fresh leaves must
be given them at least two
or three times a day.
Scatter the new leaves
over the little pile of
worms, dried old food and
excrement, and the worms

 

Fm. 4 Sileween en malbersy Tea Will soon crawl out and on
showing front view of head and thorax. to the new. It is advis-
Pees, able to keep the feeding-

tray as clean as possible, for the larvae are readily subject

to disease. In order to remove the waste matter, spread

a bit of large-meshed mosquito netting over the tray and

throw the fresh food on top of it. The worms. will

crawl up through the meshes to the fresh leaves when
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 13

the netting can be lifted up and the tray emptied. The
larve will grow rapidly, plainly increasing in size each
day. After eight or nine days they will cease feeding
and crawling around. Each one stands on the legs of
the middle of the body, and usually holds up the head
and forepart of the body, and sometimes the tail. It is
preparing to moult, i.e., to cast the skin. The moulting
should be observed in detail. After moulting each larva
will be noticeably larger and paler, and the long hairs of
the body will be replaced by short ones. The feeding
begins again, and larger and larger supplies of leaves will
be found necessary to keep the worms well fed.

The larval stage of the silkworm lasts about forty-five
days, with a moulting once every nine days (or eight or
ten). It is easy to see why these successive moultings
are necessary. The true skin of an insect is always cov-
ered over outside by a cuticle in which a horny substance
called chztzz is deposited. This chitin makes the cuticle
nearly inelastic, so that the growing insect finds its body
confined within a non-stretchable case. There is then
but one way out of this dilemma, and that is the simple
way of breaking out! And so in the life-history of all
insects the phenomenon of moulting takes place. In
nearly all cases the cuticle splits along the middle of the
back from the head to about half way to the end of the
tail, and through this rent the body issues with new cuticle.
The cast skin being very light and thin, and usually color-
less, soon disappears from view, and unless the insect be
seen precisely at each moulting time it is not easy to
ascertain how many moults occur in the life of any par-
ticular species.

The silkworms breathe through very small openings,
called spzracles, on the sides of the body. One pair of
spiracles occurs on each of nine of the body-rings. What
rings are these? Each spiracle opens into an air-tube
FIRST LESSONS IN ZOOLOGY

14

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MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 15

inside the body, and these various side-tubes lead into a
main longitudinal tube running along each side from
head to tail (fig. 5). From these main longitudinal trunks
branches and sub-branches go
to all parts of the body, the air
being distributed in the insect’s
body by a distinct system of air-
tubes called ¢rachee, and not
entering a pair of lungs (fig. 6).

Silkworms devour an _ enor-
mous amount of leaves during
the last few days of larval life,
much more indeed than they
need at that time. Later we
shall see the reason for this over-
eating. They have thick, heavy
bodies and reach a length of two
and a half inches. Make a draw-
ing of a full-grown larva from a
lateral view, showing all the legs
of one side, nine breathing holes
(tiny openings each surrounded Fic. 6. — Diagram of tracheal

‘ system in body of beetle;
by a black ellipse), and the dor- sp, spiracles; ¢,  trachez.
sal spine on the posterior end, (After Kolbe.)

The cocoon and pupa.—About a week or nine days
after the fourth moult the silkworms stop feeding and
prepare for the fifth and final one. (Occasionally a silk-
worm moults six times.) But unusual preparations are
made this time; each larva crawls alongside the edge of
the tray, or approaches some object in it, and begins to spin
silken thread from its mouth (fig. 5.) All of this spinning
should be watched closely. At first the thread is attached
irregularly and apparently aimlessly to the objects near
by, but when a sort of loose and irregular net or web of
silk has been made, the spinning becomes more regular,

 

 
16 FIRST LESSONS IN ZOOLOGY

and it is plain that the larva is making a silken case or
cocoon about itself. The spinning lasts about three days
and results in a thick, firm, white or yellowish (rarely
greenish) silken closed cocoon, within which the larva
moults. Cut one of the cocoons open a few days after
its making and there will be found within it the cast skin
of the larva and the pupa which appears after the final
larval moulting. In what habit does this pupa resemble
that of the mosquito? In what habit does it differ? The
pupal stage in the development of insects is a stage in
which the insect takes no food, is usually quiescent, and
is undergoing the final changes from worm- or grub-like
larva to winged adult. The silkworm pupa lies quiescent
in its silken case for about two weeks, sometimes a little
longer, when the pupal cuticle splits, and one end of the
silken cocoon is dissolved by a fluid secreted by the insect
within. Through this opening out crawls the moth,
damp and crumpled-looking, with the wings all compressed
into short thick pads or sacs. But these slowly expand,
the scales and hairs covering the body dry, and soon the
robust fully developed white moth walks slowly about.

Make a drawing of a net and cocoon just begun, show-
ing the larva inside at work spinning ; also a drawing of
a completed cocoon; and of a cocoon cut open showing
the mummy-like pupa within.

As the silkworm takes no food in the pupal stage (this
is true of the mosquito also) and as a great deal of devel-
opment goes on in this stage during which the wingless
larva is transformed into the very different winged imago,
it is plain that the pupa must live on food stored in the
body. It is for this reason that the larval mosquito,
the wriggler, and the larval silkworm moth, the silkworm,
devote themselves so steadily to cating and cat more
than they need for their own use. The extra food eaten
is changed into fat, or is in some way stored in the body
MOSQUITOES, SILK WORMS, AND DRAGON-FLIES 17

as reserve material on which the pupa draws during its
quiescent and fasting life.

 

  

Fic. 7.—The forest tent-caterpillar moth, CZiséocampa disstria, in its various
stages; m, male moth; 7, female moth; /, pupa; e, eggs (in a ring)
recently laid; g, eggs hatched; ¢, larva or caterpillar. Moths and
caterpillar are natural size, eggs and pupa slightly enlarged. (Photo-
graph by M. V, Slingerland.)

The moths and egg-laying.—When the silkworm
moths issue from the cocoons they make no attempt to
fly although each is provided with four wings. Some
of them, however, will be seen to keep up a rapid gentle
fluttering of the wings; these are usually males, which
are more active than the females. The males and females
are alike in color and marking, but the antenna, or feelers,
of the male are wider or bushier than those of the female ;
that is, the side branches or “ pectinations,’’ suggesting

 
18 FIRST LESSONS IN ZOOLOGY

feathers in appearance, are longer in the males than in
the females.

 

Fic. 8.—A trio of apple tent-caterpillars, CZ/s/ecampa americana, natural
size. These caterpillars make the large unsightly webs or ‘‘tents ” in
apple-trees, a colony of the caterpillars living in each tent. (Photo-
graph from life by M. V. Slingerland.)

examine a moth, noting the number of wings, number
of legs, the antennz: and eyes, and the scales or hairs
which cover the body and wings. Make a drawing,

from dorsal view, of a moth with wings outspread.
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 19

The moths will soon pair, and the females will begin
laying eggs at about the end of the first day. Each
female will lay about 300 eggs. Provide small pieces of
cloth ; place the moths on the cloths and the eggs will
be laid on them. After laying the eggs the moths soon
die. They take no food at all, indeed their mouth-parts

 

 

 

 

 

Fic. 9.—The larva of the violet-tip butterfly, Polygonta interrogationis,
making its last moult, i-e., pupating. (Photograph from life, by the
author. )

are incomplete and not able to suck flower nectar which

is the usual food of moths and butterflies. The pieces of

cloth covered with eggs should be put away in a closed
box and kept in a fairly cool place until the following
spring. When the mulberry leaves appear again, lay out

the egg-cloths in trays in a warm bright room. In a

few days the hatching will begin, and with it a new life-

cycle.
20 FIRST LESSONS IN ZOOLOGY

Other moths and butterflies.—The life-history of the
silkworm moth serves as an example of the life of all
moths, and of butterflies too, which are closely related
to moths. In every case there hatch from the eggs not
small moths and butterflies, but worm-like larve, which we
call caterpillars (figs. 7 and 8). These larve feed mostly
on green leaves, grow rapidly, moult several times, and

 

|

 

 

 

Fic. 10,—Chrysalid (pupa) of the violet-tip butterfly, Podvgonia interroga-
tionts, From this chrysalid issues the full-fledged butterfly. (Photo.
graph from life, by the author.)

finally change to pup, i.e., pupate. Before pupating some
spin a silken cocoon as the silkworm does, some may
burrow into the ground, and some simply crawl into a
sheltered spot, or hang from some twig and change into a
naked pupa or chrysalid (figs. 9 and 10). In this latter
case the color of the chrysalid usually harmonizes so
well with the surrounding leaves or bark that it is almost
indistinguishable. Almost any caterpillars that are found
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 21

may be reared in the schoolroom or at home ifthe proper
food is known and can be obtained. While some of them
will eat almost any kind of leaves most of them feed only
on one or two particular kinds. Whatever plant the
caterpillar selects outdoors is the kind of food plant it
prefers or must have.

Directions for making breeding-cages for caterpillars
are given on p. 330; so that any caterpillar found may
be brought home alive and an attempt made torear from
it the moth or butterfly of which it is only a young stage.

Excellent books about the life of butterflies and moths
are ‘Moths and Butterflies,’’ by Mary C. Dickerson,
“Every-day Butterflies,’’ by S. H. Scudder, and “ Cater-
pillars and Their Moths,’’ by Ida Eliot and Caroline
Soule.

DRAGON-FLIES

The adults.—Dragon-flies (fig. 11), or ‘ devil’s darning-
needles,’’ are familiar insects in any locality not wholly
without ponds or streams. These long, slender-bodied,
swiftly flying insects are to be seen any bright day from
early spring to late autumn darting hither and thither over
a pond or along a stream bank. They are usually bril-
liantly colored with blue or green or red, and the wings
are often strongly marked with blackish bars or blotches.
When they thus dart swiftly about they are capturing
and devouring their prey—the little gnats and midges
which dance in the air over the pond or near its shores.
Dragon-flies are the hawks of the insect world.

If one of these swift flyers can be caught in an insect
net it may be taken out and handled without fear, for
despite popular prejudice it is wholly harmless to any-
thing except small insects; these it catches in its wide
mouth and crushes with its strong jaws. But it has no
sting, nor any piercing beak or poisonous jaws. Note the
22 FIRST LESSONS IN ZOOLOGY

long, slender hind body or abdomen, made up of several
segments or body-rings ; in flight this hind body acts as
a rudder to help steer the dragon-fly in its quick turnings
and swift dashes. Note the two pairs of long wings,
transparent and delicate, but firmly supported by a com-
plex skeleton of longitudinal and cross veins ; no other
insect surpasses this one in flight. Note the three pairs
of slender weak legs; it uses its legs only occasionally
for perching, but it ses the two front pairs to form a little
sort of trap or basket
which aids the great
mouth in catching and
holding small insects when
the dragon-fly is ‘‘ hawk-
ing.”’ Note the great head,
so loosely attached to the
body behind it that it can
be turned in any direction,
and caneven be so twisted
on the neck that the top
of the head will be direct-
ed downward with the
: mouth facing directly up-
(From life.) ward. This head is com-
posed chiefly of two great shining compound eyes each
made up of many thousand eye-elements. When exam-

     

if
Lap
ea

 

pms BS a

Vic. 11.—A drayon-tly.

ined under a good hand lens the shining outer surface of
these eyes is seen to be composed of thousands of tiny
facets, each facet being the window or transparent outer
wall of one of these eye-clements. Each facet and the
eye-element behind it sce one small part of the object
looked at, so that the image produced in the sensitive part
of the back of the eye is composed of thousands of
scparate small parts, which make a sort of mosaic of
the object looked at. This seeing by compound eyes,
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 23

which is the kind of sight possessed by almost all insects
and crustaceans (crabs, lobsters, crayfishes, etc.), but by
no other animals, is called mosaic vision, and cannot be
so exact or truthful as our own.

Examine the mouth of the dragon-fly and notice the
large flap-like under lip which folds over the opening, and
behind it the strong brown jaws.

Make a drawing from dorsal view of an adult dragon-
fly with wings outspread. Make a drawing of the head
from front view.

Egg-laying.—If you watch dragon-flies darting over a
pond in summer occasionally some may be seen to swoop
down quite to the water’s surface and to strike it repeat-
edly with the tip of the abdomen. Theseare laying eggs,
and each time the water is touched a few eggs are liber-
ated and sink slowly to the bottom. If one of these ovi-
positing females can be caught alive the egg-laying may
be observed and the eggs obtained for the school aqua-
rium by holding the dragon-fly by the wings and touch-
ing the tip of her abdomen to the surface of some water
ina saucer. The eggs should then be poured into the
aquarium (for directions for making simple school aquaria
see p. 332) where, if all goes well, they will hatch into
young dragon-flies. But as this hatching will not occur
until late in the summer, and as the young dragon-flies,
called nymphs, grow very slowly and donot change into
winged adults for about a year, it will be better to find
nymphs in the pond and stock the aquarium with these
already partially developed individuals.

Nymphs.—With a rake or stout water-net (see p. 335)
scrape over the bottom of a pond and find in the mud
and slime drawn out a number of flattened, heavy-
bodied, broad-headed, six-legged creatures like the one
shown in figure 12. These are the nymphs of dragon-
flies. Each nymph will have on its back four conspicu-
24 FIRST LESSONS IN ZOOLOGY

ous wing-pads; the larger these are the older is the
nymph, and the more nearly ready to change into the
adult form. April and May are the best months for col-
lecting nymphs because the oldest ones found then are
nearly ready to change into
winged flies, and this they
may do in the schoolroom.
A careful observer of these
creatures gives the following
directions for bringing the
nymphs to maturity. ‘ Place
them [the collected nymphs]
in a wooden pail or tub. If
the sides are so smooth that
they cannot crawl up to
transform, put some sticks
in the water for them to
Fic. 12.—The young (nymph) of a crawlout on. Tie mosquito

dre -fly. (F snkins and ; :
celine eee netting tightly over the top,

 

or better, make a screen
cover; leave three or four inches of air between the
water and the netting ; feed at least once a week; set
them where the sun will reach them; and after the ad-
vent of warm spring weather look in on them early every
morning to see what is going on.”’

To feed the nymphs provide them with smaller live
insects. Mosquito wrigglers, May-fly nymphs, small
water-bugs, and any tiny swimming “beasties ’’ that can
be caught in stagnant water should be dropped alive into
the tub. The nymphs, like the adult dragon-flies, are ex-
clusively carnivorous in diet. Observe how they catch
their prey. Note that they rarely come to the surface of
the water, and that there is no indication of breathing.
In fact they breathe under water by means of gills which
are not external, but which line the posterior third of the
MOSQUITOES, SILKWORMS, AND DRAGON-FLIES 25

intestine. Water, carrying air dissolved in it, enters
through the anal opening at the posterior tip of the body,
and, after giving up its air to the gills inside, is ejected
again. The opening is guarded by some flaps which may
be seen to open and close occasionally. If a nymph be
taken out it may eject water with considerable force from
this opening.

Kill a nymph in a killing-bottle and examine it care-
fully. Note the wing-pads ; note the long, strong legs;
also the large head with conspicuous compound eyes and
short delicate antenne. Examine especially the mouth-
parts, and note how the long under lip is folded over the
mouth-opening, but can be unfolded and extended from a
third to half an inch ; note the two grasping parts at its tip
(fig. 13). This long, grasping under lip is the prey-catch-
ing organ of the nymph, while the pair of strong jaws
which open and shut laterally are the organs which crush
the body of its prey and force its blood into the hungry

 

Fic. 13.—Young (nymph) dragon-fly, showing lower lip folded and
extended. (From Jenkins and Kellogg.)

mouth of the destroyer. Make a drawing of a nymph
from dorsal view, with its under lip extended and pinned
out. Make a drawing of the front of the head, with the
under lip folded like a mask over the face.

The transformation to winged stage.—During the
life of the nymph it grows and develops from a very
small creature without wing-pads to a much larger one
with conspicuous pads. During this growth it moults
several times. iust as the growing silkworm does. Imme-
26 FIRST LESSONS IN ZOOLOGY

diately after moulting the body wall is very soft, and light
greenish or grayish in color, but it gradually hardens and
darkens. When its growth and development is com-
pleted the nymph will climb out of the water on some
firm object, and, fixing its feet solidly, will proceed to
transform, by means of a final moult, into the adult or imago
stage. The cuticle or horny
outer-skin layer splits along
the middle of the back of the
head and front part of the
body, and out of this crack
the winged dragon-fly slowly
emerges. When this trans-
formation takes place out-
doors it usually occurs early
in the morning. ‘If one can
be out at the pond by six
o’clock some clear morning,
when the adults of some
dragon-fly that is known to
be common are_ beginning
(Natural to appear, he may be sure

 

Fic. 14. — Damsel-flies (narrow-

winged dragon-flies).
size; from life.) of finding them transform-

ing. There will be some nymphs crawling up the banks,
imagos pulling themselves out of their old nymph skins,
others drying their wings, others ready to fly, and all
within a few feet of the margin of the water.
At noon one would find only dry and empty nymph-skins
clinging to the sedges. And there, unless beaten down
by wind or rain, each empty husk still clings, useless
now, or sometimes furnishing a night's shelter to some
mendicant plant-bug, until the festive, sportive, aerial
life of its former occupant has run its swift course.”

or a good account of dragon-flics see pp. 54-72, in
“ Outdoor Studies,” by James G. Needham.
CHAPTER II

TOADS AND TADPOLES

While the life-history of most of the backboned
animals shows no such startling transformations or met-
amorphoses as that of the insects we have studied, yet
among toads, frogs, and salamanders, forming the class of
backboned animals known as amphibians or batrachians,
there is an interesting and well-marked metamorphosis.
A newly hatched bird is much smaller and weaker than
its parents, its feathers are different, and it usually has to be
cared for and fed for some time, but it is unmistakably bird-
like in appearance, and its development to adult form is
gradual and without startling changes. The same is true
of kittens and puppies, or young lions or camels, and true,
also, for the most part, of fishes and of snakes and lizards.
But the young toad or frog, which we call tadpole, looks,
and truly is, much more like a fish than like its parent,
and therefore in its growth and development it undergoes
a marked transformation.

The eggs and hatching.—In the spring, April and
May, the frogs and toads begin their croaking and trill-
ing, and then is the time to look in the ponds for the eggs.
Indeed the ponds had better be watched as soon as the
ice goes out. Hunt in the shallow water along the banks.
Toads’ eggs lie in long strings of a gelatinous, jelly-like
substance, usually wound about submerged sticks or the
stems of water-plants, while those of the frog are found
in small bunches or masses of the jelly. They are small,

27
28 FIRST LESSONS IN ZOOLOGY

shining, black, and bead-like, and in the toad strings are
arranged in single rows. If they have been recently laid,
the enclosing jelly mass will be clean and clear, but it
soon becomes partly covered with fine mud, when the
eggs are not so easily seen. Bring some egg masses to
the schoolroom and keep them in water in a light warm
place, but not in the direct sunlight.

 

Fic. 15.—Garden toad. (From life.)

Examine the eggs several times a day, as hatching
occurs in two or three days after they are laid. The
developing embryo can be clearly seen through the trans-
parent jelly. Watch for their first movements and note
their change in form. Finally they wriggle out from the
jelly mass and swim freely in the water, or attach them-
selves, by means of a little V-shaped sucker on the head,
to some solid object. They are not like adult frogs or
toads at all, but are the familiar little fish-like tadpoles
(fig. 16).

The tadpoles.—To rear tadpoles successfully in the
schoolroom requires some pains. First, a proper little
artificial pond must be made. Professor Gage, of Cornell
University, who has successfully reared many broods,
gives the following directions for caring for them:
TOADS AND TADPOLES 29

“To feed the tadpoles it is necessary to imitate nature
as closely as possible. To do this a visit to the pond
where the eggs were found will give the clue. Many
plants are present, and the bottom will be seen to slope
gradually from the shore. The food of the tadpole is the
minute plant-life on the stones, the surface of the mud, or
on the outside of the larger plants. Make an artificial

 

Fic. 16.—Tadpoles. (Photograph from life by Cherry Kearton ; permis-
sion of Cassell & Co.)

pond in a small milk-pan, or a large basin or earthenware
dish. Put some of the mud and stones and small plants
in the dish, arranging all to imitate the pond, that is, so
it will be shallow on one side and deeper on the other.
Take a small pail of clear water from the pond to the
schoolhouse and pour it into the dish to complete the
artificial pond. The next morning when all the mud has
settled and the water is clear, put thirty or forty of the
little tadpoles which hatched from the egg string, into
the artificial pond. Keep this in the light, but not very
long at any one time in the sun.
3° FIRST LESSONS IN ZOOLOGY

‘One must not attempt to raise too many tadpoles in
the artificial pond or there will not be enough food, and
all will be half-starved. While there may be thousands
of tadpoles in a natural pond, it will be readily seen that,
compared with the amount of water present, there are
really rather few.

“ Every week, or oftener, a little of the mud, and _per-
haps asmall stone covered with the growth of microscopic
plants, and some water should be taken from the pond to
the artificial pond. The water will supply the place of
that which has evaporated, and the mud and stones
will carry a new supply of feed.”

The tadpoles will begin to change very soon. Make
a drawing of one just hatched from the egg, examining
it with a hand lens. Note the gills on the sides of the
neck, the V-shaped sucker on the head, and the absence
of legs and eyes. Watch sharply for the first changes.
What are they ?

It takes a tadpole about two months from the time of
hatching to complete its development and hop out of the
water as a little toad or frog. In this process of develop-
ment the following changes occur : eyes appear ; the gills
are lost ; four legs develop; the tail is gradually lost,
and lungs are formed inside the body. The development
of the lungs cannot be actually seen, but its course is
made apparent by the behavior of the tadpoles. While at
first they remain under the water nearly all the time,
breathing by means of their gills the air dissolved in the
water, as they grow older they come more and more
often to the surface and gulp down air through the mouth.
Lungs are developing, and are being more and more
used for breathing air from the limitless supply above.

Observe carefully the process of the disappearance of
the tail. Does it drop off suddenly ? Is it lost before the
legs develop ? Which pair of legs appears first ? The order
TOADS AND TADPOLES 31

of their appearance differs in the toad tadpoles and the
frog tadpoles ; if both kinds are being reared determine
this by observation.

Make a drawing of a tadpole just after its legs appear,
and compare with the drawing of the newly hatched
tadpole ; make also a drawing of a little toad or frog
when it first finishes the tailed tadpole stage and hops
out of the water.

While the development of the tadpoles is going on in
the schoolroom observations on the growth and changes
of those in the natural ponds outdoors should be made.
Does development go on more rapidly indoors than out ?
Where do the little toads and frogs go after they leave the
outdoor ponds?) On what do they feed now ?

Toads and frogs.—Adult toads and frogs are carniv-
orous, instead of feeding on tiny plants as in their tadpole

stage. They snap up all kinds of insects, worms, and
snails ; when full grown they

will eat younger frogs, cray-
fish, small turtles, and fish,
and may also occasionally
capture small birds. A few
grown-up toads and frogs
should be kept in the school- “4
room in a box with at least
one glass-side and covered
over with netting. Keep q Fic. 17.—Garden toad. (From life.)
dish of water in the box, and the bottom covered with
clean moist sand. Feed the toads live insects, worms,
and snails, or bits of raw meat. How does the toad catch
its prey or seize the offered food ?

Both toads and frogs do much good by destroying
many insects. One observer, quoted by Professor Gage,
reports that a single toad disposed of twenty-four cater-
pillars in ten minutes, and that another ate thirty-five

 
32 FIRST LESSONS IN ZOOLOGY

celery-worms within three hours. This observer esti-
mates that a good-sized toad will destroy nearly ten
thousand insects and worms in a single summer. The
garden can have no more desirable animal inhabitants than
toads; not only should they not be killed but it would be
worth while to introduce them in flower and vegetable
gardens where they are not naturally present.

For a good account of tadpole-rearing see ‘‘ The Life
of a Toad,’’ by Professor 5. H. Gage.
CHAPTER III

A BIRD’S NEST, AND OTHER ANIMAL HOMES

The animals whose life-history we have so far studied
do not take care of their young, though making certain
provision for them nevertheless. The female mosquito,
although an aerial creature, is careful to lay her eggs on
the surface of water so that the young will find them-
selves at the moment of hatching in their proper element ;
the female silkworm moth, although she never takes
food herself, in nature would certainly lay her eggs on
mulberry trees, where the young, on hatching, could find
at hand their proper food. Such is the habit of all moths
and butterflies. Some of them indeed take food in their
adult stage, but this is always liquid nectar from flowers,
or other sweet juices, and water, and their mouth-parts are
formed into a long, flexible, coiling, sucking proboscis.
They could not eat green leaves if they would ; and yet
each moth and butterfly mother seeks out, at egg-laying
time, that particular plant, unknown to her as food, the
green leaves of which the young caterpillars must live
upon ; truly a remarkable instinct! But beyond this care
in laying their eggs in suitable places the butterflies and
moths have nothing to do with their young.

And so it is with most of the lower or simpler animals,
and with many of the vertebrates (backboned animals),
most of the fishes for instance, the amphibians, and the

reptiles. These animals pay little or no attention to
33
34 FIRST LESSONS IN ZOOLOGY

their young after birth ; indeed many of the lower ones
die before the young are hatched, and those that do not
may have gone a long distance away before that time.
But among the higher vertebrates, the birds and mam-
mals, and among a few particularly interesting inver-
tebrates, as the social insects and others, the parents
give much care and protection to their young, building
homes for them, providing them with food, and teaching
them to help themselves. Almost all animal homes
are built primarily for the protection and housing of
the young, although the parents, may, and during the
rearing of the young naturally do, largely live in them
themselves. Asan example of an animal home, we may
observe the construction of a bird’s nest, together with the
egg-laying and incubation and the care of the fledglings.

A Bird’s nest.—In spring and early summer, the
nesting-times, find close to the schoolroom a pair of birds
that have begun a nest. By keeping sharp watch in
trees and bushes they will surely be found, though most
birds hide their nests as effectively as possible. Robins
are especially good birds to watch, because they are
not easily frightened from their work, because they
build a large nest, and because they gather their nesting
materials mostly in the near vicinity of the nest. Be-
cause the robin’s nest is in a tree, it may not be so easy
to watch as the nest of some bird that builds in hedges or
bushes. Find a robin or other bird carrying a straw in
its bill and trace it ““home,”’

In observing the nest-building, egg-laying, and incu-
bation try to answer the following questions: Do both
birds take active part in building, or but one, and if one,

which one, the male or female, and what does the other
do? What materials are used? Is the nest composed
chicfly of one kind of material, or nearly equally of sev-

ral? What ‘tools’ of the bird are used in building ?
A BIRD’S NEST, AND OTHER ANIMAL HOMES 35

When does building begin? How long does it last?
How soon after finishing the nest are the eggs laid?
Are all the eggs laid at one sitting ? Do both birds take
part in incubation, i.e., sitting, or but one, and if but one,
is it the male or the female?
What does the other do?
How long before the eggs
hatch? Do they all hatch at
the same time?

After hatching the care of
the fledglings should be well
watched. Do both parents
bring food? How many
times is food brought in one
hour, or ifso much time can
be given to continuous watch-
ing, in two or three?) What
is the food? Is the nest
cleaned? If so, how often ?
When are the first flying
lessons given? How long
do the young birds continue ae Bs yeas fe ee

nade of sycamore down (one-half
to come back to the nest at natural size).
night after they first leave it?

Other incidents in the course of nest-building incu-
bation, and care of the young birds will certainly be
noted if sufficient observation to answer the above ques-
tions is given. Attacks by cats and bluejays (fig. 19),
disputes between the parent birds, accidents from high
winds or other causes are all likely to enter into the
course of nesting. And the behavior of the parent
birds under such more or less unnatural circumstances

 

will be interesting to observe and record.
While some pupils are watching a robin’s nest others
should observe the nesting of other kinds of birds—the
30 FIRST LESSONS IN ZOOLOGY

bluebird, wren, groundbird, catbird—any familiar kind
that can be found at work.

In Chapter XV_ of this book, which is devoted to
suggestions for studying the life of birds, further attention
is given to nesting and care of the young. See Chapters
XVII-XXI in Baskett's ‘The Story of the Birds,’’ and

Chapter VI in Chapman’s “ Bird-life.”

 

 

 

 

 

Fic, 19.—Oriole’s nest with skeleton of bluejay suspended from it; the
bluejay probably came to the nest to eat the eggs, became entangled
in the strings composing the nest, and dicd by hanging, (Photograph
by S. J. Hunter.)

Homes of insects and spiders.—The insects which
build the most elaborate homes and take the greatest
care of their young are the so-called social insects—the
communal ants, bees, and wasps. As a later chapter
(Chapter XX) in this book is entirely devoted to the
life-history and habits of these insects, we may omit any
account of them here. But only a few species of bees,
namely, the bumble-bees and the honey-bee, live in com-
A BIRD’S NEST, AND OTHER ANIMAL HOMES 37

munities, and similarly only a few kinds of wasps. All
the ants, however, and more than 2000 living species of
them are known, have acommunal life. But the solitary

 

Fic. 20.—An oak-gall (California) home of a small four-winged gall insect;
in upper figure the gall on oak-branch; in lower, the gall cut open to
show the inside. (Upper figure slightly reduced; lower figure, natural
size; from specimen.)

bees and wasps give more or less special attention to

their young, all of them building homes for them, and

providing them with food either by storing it in a closed
nest and leaving the young to supply themselves from it,
or by leaving the nest open and bringing food daily after
38 FIRST LESSONS IN ZOOLOGY

the larva: hatch. The instincts connected with nest-
making and caring for the young shown by the non-
social or digger wasps and the solitary bees are remark-
able, and offer an intensely interesting field of outdoor
observation and study. (See the special account of these
habits in Chapter XII on insects.)

Many insects make for themselves simple burrows or
nests in the ground or wood. When not feeding they
can retire to these burrows and lie there somewhat pro-
tected from their enemies, the birds and the predaceous
insects. The eggs of many insects are thrust by the
female into the soft tissue
of leaves and stems, or
even into bark and hard
wood. When the young
hatch they burrow about
in the plant or tree, feed-
ing on the juices or other
plant substance, and re-
maining out of sight and
reach of their outside
enemies. The larve of
certain moths burrow
about in the soft inside
tissue of leaves, the whole
life of the moth except its
short adult stage being

: assed _ insi leaf.
Fic. 21.—Egg-cocoon of the labyrinth , nside the
spider, with side removed to show These moths are called
egy-packets and chambers. (Two and 7, Sa eee
one-half times natural size; after Snod- leaf-miners. The larvae of
grass. ) some moths and of many
small four-winged hymenopterous midges live through
their immature life in galls (fig. 20) on live plants. Th
mother, with a tiny, pointed ovipositor, thrusts her eggs
into soft plant tissuc, which closes over them. When the

 

oO

1
A BIRD’S NEST, AND OTHER ANIMAL HOMES 39

larve hatch, their wriggling and feeding irritate the sen-
sitive tissue so that it grows in an abnormal way and
forms a gall, often very large, about the insects.

All these burrows and galls may be looked on as the
simplest kinds of houses or homes, the young insects
living in them, and being protected by them.

Most spiders spin silken cocoons (fig. 21), or sacs, in
which to deposit their eggs. Some spiders carry this
egg-filled cocoon (fig. 22) about with them for the sake
of protecting the eggs. After hatching the spiderlings
remain in it a short time, feeding on each other! Thus
only the strongest survive and issue from the cocoon to

 

Fic, 22.—A female running spider (Zycoside) carrying its egg-sac about
attached to its spinnerets. (From Jenkins and Kellogg.)

earn their living in the outer world. With certain species
of spiders the young after hatching leave the cocoon and
gather on the back of the mother and are carried about
by her for some time. In connection with their webs
or snares many spiders have silken tunnels or tubes in
which to lie hidden, a sort of sheltering nest. Those
that live on the ground make for themselves cylindrical
burrows or holes in the ground, usually lined with silk,
in which they hide when not hunting for food. Espe-
cially interesting among these many kind of nests are the
burrows of the various trap-door spiders (figs. 23 and 24).
These spiders are common in California and some other
far Western States. Their burrow or cylindrical hole is
closed above by a silken, thick, hinged lid or door, a little
larger than the hole in diameter, and neatly beveled on
the edge, so as to fit tightly into and perfectly cover
40 FIRST LESSONS IN ZOOLOGY

the hole when closed. Its upper surface is covered with
soil, bits of leaves, and wood, and resembles very exactly
the ground surface about it. We have found these trap-
door nests in California in moss-covered ground, and

 

 

Fic. 23.—Trap-door spider (California) with two burrows, one with door
3 P I : , :
open, one with door closed. (Natural size; from life and specimens. )

here the nest lids were always covered with green,
growing moss.

An English naturalist who studied the habits of these
spiders found that if he removed the soil and bits of bark
and twigs, or the moss, from the upper surface of the lid
the spider always recovered it. It is of course plain that
by means of this covering the nest is perfectly concealed,
the surface of the closed door not differing from the sur-
rounding ground surface. This naturalist finally removed
the moss not only from the surface of a trap-door, but
also from all the ground in a circle of a few fect about the
nest. The next day he found that the spider had brought

moss from outside the cleared space and covered the
A BIRD’S NEST, AND OTHER ANIMAL HOMES 41

door with it, thus making it very conspicuous in the
cleared ground space. The spider’s instinct was not ca-
pable of that quick modification to allow it to do what a
reasoning animal would
have done—namely, to
cover the trap-door only
with soil to make it
resemble the cleared
ground about it.
Another interesting
species is the turret-
spider, that builds up a
little tower of sticks and
soil and moss above its
burrow (fig. 25). The
sticks are an inch or two
in length, fastened to-
gether with silk and so
arranged as to make a
five-sided turret two or
three inches high. This
turret - building spider
carries about its egg-
cocoon. A female of this
: : ee ee Fic. 24.—Burrow of trap-door spider
species in captivity was cut open to show interior. (One-half
observed to pay much _ natural size; from specimen.)
attention to caring for the cocoon. “If the weather
was cold or damp she retired to her tunnel; but if
the jar in which she lived was set where the sun could
shine upon it she soon reappeared and allowed the
cocoon to bask in the sunlight. If the jar was placed
near a stove that had a fire in it the cocoon was put on
the side next the source of warmth ; if the jar was turned
around she lost no time in moving the cocoon to the
warmer side. Two months after the eggs were laid the

 
42 FIRST LESSONS IN ZOOLOGY

young spiders made their appearance and immediately
perched upon their mother, many on her back, some on
her head, and even on her legs. She carried them about
with her and fed them, and until they were older they
never left their mother for a moment.”

 

Fic. 25.—‘ Turret” or above-ground part of nest of turret-spider, (Natural
size; from specimen. )

Homes of the backboned animals.—Among the fishes,
the lowest of the backboned animals, most species con-
tent themselves with the laying of many eggs in a situa-
tion best suited for their safe hatching. But some species
show interesting domestic habits. The female catfish
swims about with her brood much as a hen moves about
with her chickens. Some of the larger ocean catfish of the
tropics receive the eggs or the young within the mouth for
safety in time of danger. Certain sunfishes care for their
young, keeping them together in still places in the brook.
They also make some traces of a nest, which the male
A BIRD’S NEST, AND OTHER ANIMAL HOMES 43

defends. The male salmon scoops out gravel to make a
shallow nest, in which the female deposits her eggs, after

‘JSoUu SH pure (szevuusgupy) ysysory W—"9z ‘OI

 

(‘Teg ‘sajesuy sot

“od Burystqng Isai NO Jo uolssttusad Ag)

 

se : Ase ee ete ie

which he covers the eggs. The males of the species of
pipe-fish and sea-horses receive the eggs of the female
44 FIRST LESSONS IN ZOOLOGY

into a groove or sac between the folds of skin on the
lower part of the tail, Here they are kept until the little
fishes are large enough to swim about for themselves.
The brave little stickleback builds a tiny nest about an
inch and a half or two inches in diameter, with a small
opening at the top. In this nest the eggs are laid, and
the young fish remain in it some time after hatching.
The male parent jealously guards it and fights bravely
with would-be intruders.

The frogs and salamanders (batrachians) and the lizards
and snakes (reptiles) rarely show any care for their
young, the eggs of most batrachians being laid in the
water and left by the female. The males of the Surinam
toad receive the eggs in pits of the spongy skin of the
back, where they remain until the young hatch. Snakes’
eggs are laid under logs or buried in sand, and no fur-
ther attention is given them by the parent.

Among the birds, as we know, nest-building and care
of the young are the rule. But not all birds make nests.
On the rocky islets of the northern oceans, where thou-
sands of puffins and auks and other maritime birds gather
to breed, the eggs are laid on the bare rock (fig. 27).
At the other extreme is the tailor-bird of India, which
sews together leaves with fibrous strips, plucked from a
growing plant, to form a long, bag-like nest. The nests
of the orioles and bush-tits are also good examples of
elaborate nest-making. In the degree of care given the
nestlings there is also much difference. The robin brings
food to the helpless young for many days, and finally
teaches it to fly and to hunt for food for itself. Young
chickens are not so helpless as the nesting robins, but
are able to run about, and, under the guiding care of the
hen mother, to pick up food for themselves.

Among the mammals the young are always given some
degree of care. Excepting in the case of the egg-laying
T, AND OTHER ANIMAL HOMES 45

A BIRD’S NES

 

Fic. 27.—-Murres on Walrus Island, Behring Sea. Note the eggs scattered about over the bare rocks,
lite by the Fur Seal Commission.)

 

(Photograph from
46 FIRST LESSONS IN ZOOLOGY

duck-bills, the lowest of the mammals, the young are
born alive—that is, not hatched from eggs laid outside
the body—and are nourished after birth, for a shorter or
longer time, with milk drawn from the body of the mother.
The nests or homes of mammals present varying degrees of
elaborateness, from a simple cave-like hole in the rocks
or ground to the elaborately constructed villages of the
beavers, with their dams and conical several-storied
houses. The wood-rat piles together sticks and twigs in
what seems, from the outside, a most haphazard fashion,
but which results in the construction of a convenient and
ingenious nest. The moles and pocket-gophers build
underground nests composed of chambers and galleries.
The prairie-dogs make burrows in groups, forming large
villages.

We are familiar with the devotion to their young dis-
played by birds and mammals. The parent will often
risk or suffer the loss of its own life in protecting its off-
spring from enemies. Many mother-birds have the in-
stinct to flutter about a discovered nest, crying, and
apparently broken-winged, thus leading away the preda-
tory fox or weasel to fix his attention on them and to
leave the nest unharmed.

See Beard’s ‘Curious Homes and their Tenants.”’
PART II

THE PARTS OF ANIMALS AND HOW THEY
ARE USED

CHAPTER IV

THE GRASSHOPPER AND THE SNAIL

An animal’s body composed of parts.—The body of
every animal, except the very simplest ones, is composed
of a few or many parts, each part having some special
use or thing to do. A dog has its body made up of head,
trunk, legs, and tail—the head comprising skull with
brain inside, jaws with teeth, tongue, eyes, ears, etc.;
the trunk comprising a host of internal parts, as the back-
bone, heart, lungs, stomach, intestines, etc., and the legs
in turn composed of a series of bones to which are attached
muscles, among which run nerves and blood-vessels, the
whole being covered with a hairy skin. The study of the
parts, external and internal, of an animal is called anat-
omy, and the study of the uses or functions of the parts is
called physiology. In earlier years anatomy and physi-
ology were studied wholly separately, as they still some-
times are. But we know that the things animals do, and
the ways in which they do them, depend upon the parts
of the body and upon the special character of these parts.
We know also that these parts are specially developed
and fitted to do certain things or perform certain functions

47
48 FIRST LESSONS IN ZOOLOGY

   
   

Thies

Fic. 28.—Locusts on
wild oats. (Nat-
ural size; from life. )

in special ways. That is,
the structure of a part and
its function or business are
closely related. A grass-
hopper’s hind legs are spe-
cially long and strong so as
to enable the grasshopper to
hop; or we may put it differ-
ently and say that the grass-
hopper can hop because its
hind legs are specially long
and strong. In whichever
way we look at this relation between
the power of an animal to do some-
thing in a special way and its posses-
sion of parts specially fitted for doing
this something, whether it be hopping,
or flying, or singing, or breathing
under water, it must be kept always
plainly in mind that such a close re-
lation does exist. Therefore when we
study the make-up of an animal, ex-
amining carefully the various parts of
the body, we should always remember
that this particular make-up or structure
is closely connected with the things the
animal can do, and the special manner
in which it does them.

The grasshopper. — Grasshoppers,
better called locusts, of some kind can
be readily found along roadsides or in
fields (fi
mens, kecping some alive and dropping

g. 28). Collect several speci-

the others into the killing-bottle (see
p. 335). Examine carefully a dead speci-
THE GRASSHOPPER AND THE SNAIL 49

men. Note thatthe body is made up of rings or segments.
In what part of the body are these rings plainest? The
legs are attached to the middle part of the body called the
thorax, of which the front part (to which the front legs
are attached) is movable and is covered over by a sort of
saddle-shaped hood, while the hinder part is solid and
box-like. How many pairs of legs are there? Examine
a single leg and make a drawing of it, showing of how
many parts it is composed and how each part appears.
Of what use are the claws and the little pads on the
under surface of the foot? To what part of the body
are the wings attached? Note how the narrow thicker
fore wing covers and protects the plaited delicate hind
wing when the wings are folded. When the locust flies
for long distances it rises high into the air, until it finds
an air current; then it simply lets its large outspread
hind wings act as flat sails to hold it up, thus allowing
it to float for many miles. In this way the Rocky Moun-
tain locusts sail or fly sometimes a thousand miles; all the
way from Wyoming to Kansas. Note the many veins
in the wings. What are these for? Draw a front wing
and a hind wing.

On the head find two large compound eyes (see p.
22), three very small simple eyes, a pair of many-
jointed feelers or antennz, used both for feeling and prob-
ably also for smelling, and a set of mouth parts consisting
of an upper lip, a pair of hard, blackish-brown jaws or
mandibles, a second pair of jaw-like parts called maxille,
each made up of several small pieces and a small palpus
or feeler, and an under lip bearing two more small palpi.
With the mandibles the locust bites off, and with the help
of the other parts, chews bits of leaves, green stems, etc.
The palpi are believed to be organs for feeling and tast-
ing the food. Draw the front of the head, naming the
different parts.
5° FIRST LESSONS IN ZOOLOGY

Note that almost the whole outer surface of the body is
covered with a firm, smooth coat, the chitinized cuticle,
that is, the horny outer layer of the skin. The skin
of the neck, however, and that at the bases of the legs
and wings is soft. Why is this necessary ? What is the
most obvious use of this hard outer covering? Note that
the soft skin of the neck is well protected by the projecting

Antenne

“nr

  
  
 

auditory organ
i

   

‘ocellus /
f head compound eye

1

'
pronolum }
as Ldhorar

    
 

  
 

7 ges

   
 
      
 

\
COra
i
Vrochanter

 
 
  

T
femur .
tibia” 7h

a
iarsal segments

Vic. 29.—-Locust with external parts named,

saddle-shaped horny picce on the front thoracic body-
ring. Another use of the firm cuticle, or exo-skeleton,
as it is called, is to afford solid points of attachment for
the many muscles of the body, the locust having no
bones or any kind of internal skeleton. (In a few places
there are processes or continuations of the exo-skeleton
projecting internally.)

That part of the body behind the thorax is called the
abdomen. [xamine the upper side of the first (nearest
the thorax) body-ring of the abdomen, and find two
small, nearly circular, thin places looking like little
windows. These are the hearing organs, or tympana, of
THE GRASSHOPPER AND THE SNAIL 51

the locust. The sound-waves striking against these thin
tightly stretched bits of the body wall, set them into
vibration, and these vibrations stimulate a tiny nerve
which touches each tympanic membrane on the inside
and leads to one of the internal nerve-centers. This is
a much simpler kind of ear than we possess, and the
locust probably cannot hear nearly as well as we can.
Note on each side of each abdominal body-ring (except
the last) a tiny blackish spot. These are breathing
pores or spiracles like those of the silkworm (see p.
13). The locust does not take in air through nostrils
en the head or through the mouth, but through these
numerous pores. There is also a spiracle near each
tympanum, and one on each side of the thorax near the
insertion of the middle legs. At the very tip of the abdo-
men are several small projecting parts which differ in the
male and female. The female has two pairs of strong,
curved, pointed pieces called the ovipositor or egg-laying
organ. When the locust is ready to lay its eggs, by
means of this strong ovipositor it bores a hole in the
ground into which the abdomen is pushed and the eggs
laid at the bottom. The male locust has a swollen,
rounded, abdominal tip, with a few short inconspicuous
pieces on the upper surface.

Examine now a live locust and see how it uses its legs
in walking and hopping ; how it moves its jaws sidewise,
not up and down as with us; how its antenne keep
‘‘feeling” about in front of it when it is walking; how
the abdomen keeps up a slight but distinct and regular
expanding and contracting. This movement forces air
in and out of the body through the spiracles; it is the
breathing motion.

Make a drawing from lateral view of the whole body
of the locust, showing and naming all the parts studied.

For a more detailed account of the external structure
52 FIRST LESSONS IN ZOOLOGY

of the locust see Comstock and Kellogg's ‘‘ Elements of
Insect Anatomy,’’ Chap. II.

The pond snail.—Pond snails may be found in almost
any pond, and live specimens may be easily kept in the
schoolroom aquarium or simply in bowls or glass jars
of water (fig. 30). They should be fed pieces of lettuce
or cabbage leaves. Observe the habits of the snails;

a i ry z i)

liv Ty i ae E

      

 

  

 

  
   

 

i i if}

       

 

Fic. 30.— Pond snails in a battery-jar aquarium. (One third natural
size; from life.)
how they come to the surface to breathe ; how they crawl
about; how they eat by rasping off bits of the leaves
with the rough, horny tongue; how they protrude from
and withdraw into the shell; how the feelers move in
and out.

Ikxamine a specimen with body extended from the
shell, and note that it is not made up of segments or rings,
but is a soft, unsegmented mass with a firm, muscular,
flattish disk on its lower side called the foot. How does
THE GRASSHOPPER AND THE SNAIL 53

the snail ‘‘walk’’ by means of this ‘‘ foot”? The body
is covered by the mantle, an edge of which may be seen
just at the margin of the shell. The soft, flexible body
and firmer muscular foot can both be withdrawn into the
protecting shell.

Find on the head a pair of extensible tentacles, the
feelers, with the eyes (dark spots) at their bases. Most
other snails and slugs have two pairs of tentacles or
horns, the eyes being on the tip of the second pair.
Find also the mouth, and examine with a lens the pecul-
iar ribbon-like radula or tongue, which is covered with
fine curved teeth. The radula is drawn back and forth
across the food, and by it small particles of the leaf are
rasped off. Leaves which have been fed on will show
the rasped or scraped places.

Find also, usually just at the surface of the water,
when the snail has come up to breathe, a small hole on
the right side of the body; this is the breathing pore,
and air entering here passes into a small sac-like space, a
simple kind of lung.

Examine a shell and note the following parts: the
aperture at the large end, the apex or pointed end,
the lip or outer edge of the aperture, the lines of growth
parallel with the lip, the suture or spiral groove on the
outside, the spire comprising all the whorls or turns,
and the columella or inner axis of the spire. Do the
whorls of all the shells turn the same way? What is
the use of the shell?

Make a drawing of the right-hand side of a snail and
its shell representing the animal fully extended; name
all the parts of the snail and shell.

If pond snails cannot be found, garden snails or slugs
may be studied. The slug is a snail-like animal without
a shell.
CHAPTER V

THE SUNFISH AND THE SPARROW

The two animals whose external structure we have
studied are both backboneless or invertebrate animals.
Most of the smaller animals are without internal bony
skeletons and hence without backbones. This is true of
the sponges and sea-anemones, the starfishes, the worms,
the crayfishes, crabs and lobsters, the centipedes, and the
spiders, as well as of the insects and the snails, slugs,
and clams. Contrasted with these backboneless animals
are the backboned ones, or vertebrates, including the
fishes, amphibians, reptiles, birds, and mammals or
quadrupeds. We shall now examine the external struc-
ture of two backboned animals, a fish and a bird.

The sunfish (fig. 31)—Some kind of sunfish can be
found in the streams of any part of the United States,
except in Washington and Oregon, and in the higher
Rocky Mountains. Where sunfishes cannot be obtained,
bass or perch or gold-fish may be used for study. Speci-
mens should be taken alive if possible, and kept in a
large jar or tub of fresh water.

Examine a live sunfish. Note the deep, flattened trunk
of the body, and the paddle-like tail. The head is
closely fitted to the trunk without any neck. How are
the scales arranged? Remove a scale and examine it
under a hand Jens. What sort of an edge has it? Ex-
amine the fin, called the dorsal fin, on the back. Note
that its front part is composed of spines, and its posterior

54
55

THE SUNFISH AND THE SPARROW

 

Fic. 31.—A sunfish.

 

(One-half natural size; from specimen.)

 
56 FIRST LESSONS IN ZOOLOGY

part of soft rays jointed and branched, both spines anc
rays being connected by and supporting a thin skin. At
the end of the tail is the caudal fin; in front of the tail
on the under surface is the anal fin, while still in front of
this is the pair of ventral fins, and on the sides of the
body back of the mouth are the pectoral fins. How is
each of these fins composed? The ventral fins correspond
to the hind legs of other backboned animals, while the
pectoral fins correspond to the forelegs, wings, or arms.
Watch the fish swim and determine the use of each kind
of fin. Professor Needham gives the following directions
for doing this: ‘‘ To learn the use of the pectoral and
ventral fins catch the fish with the hand, avoiding the
sharp spines at the front of the pectoral and anterior
dorsal fins; fold the pectoral fins backwards, flat against
the sides of the body; pass a rubber band back over the
head and around these fins to keep them so. Keep the
fish under water while attempting to depress the pectoral
spines, for in air it will keep them rigidly erect. Pass
another rubber band about the ventral fins. Then liber-
ate the fish and watch it. What position does its body
assume? Release the paired fins and fasten down the
dorsal and anal fins with rubber bands. Liberate the
fish again, and observe how it gets along without the use
of these fins. What kind of a course does it take through
the water?’”’

Examine the eyes. Are there eyelids? In front of
the eyes are two pairs of nostrils. Examine the inside
of the mouth. Is there a tongue? Where are the teeth
situated, and in what direction do they point? What
advantage to the fish is it to have the teeth pointing as
they do?

Lift up the flap, called opercular flap, in front of one
of the pectoral fins and bend it forward. Under it are
four gill arches, each with a double fringe of gills. The
THE SUNFISH AND THE SPARROW 57

cavities enclosed by the gills are called gill-pouches.
Note the gill-rakers, short and blunt, on the first gill
arch. Note also, on the under side of the flaps turned
back, delicate red gill-like structures covered by a mem-
brane. These are the false gills. The true gills are
organs by means of which the fish breathes under water.
Note the fish continually gulping water. This water with
air dissolved in it passes through the mouth into the
gill-pouches and out under the operculum. Thus the
dissolved air in the water comes in contact with the gills
passes through the delicate gill membranes and into the
blood, which runs in many fine capillaries through the
gills, while at the same time the blood itself gives up
carbonic dioxide, which passes out through the gill
membranes into the water. In this way the blood is
purified.

Make a drawing from lateral view of the sunfish, show-
ing and naming the parts studied.

Professor Needham gives the following directions for
seeing the flow or circulation of the blood in the caudal
fin of a fish:

‘« Wrap the fish in a wet towel, leaving the caudal fin
exposed, and place it ona low box beside the microscope,
with its caudal fin extending across the center of the
microscope stage. Spread the fin out flat on a glass slip
upon the stage, so as to bring a thin portion of it into the
field, and examine it with low power. If the fish refuses
to lie quietly, pour a little chloroform on the towel near
its mouth.

‘Observe the conspicuous, dark, irregular pigment
cells scattered throughout the epidermis of the fin.

“The larger blood-vessels are of two kinds; (1)
arteries, bringing blood out into the fin, and (2) veins,
conveying the blood back to the body again. The
smaller ones are the capillaries connecting the arteries
58 FIRST LESSONS IN ZOOLOGY

with the veins, and distributing the blood throughout the
tissues of the fin.

‘© Observe that the blood consists of a fluid plasma, in
which floats numerous corpuscles. Observe that the
blood appears red in the arteries and veins, where the
corpuscles are accumulated, but only slightly reddish or
yellowish in the capillaries, where the corpuscles form
but a thin layer.

“Does the blood travel faster in the arteries and veins,
or in the capillaries ?

“ Place a bit of cover-glass over a very thin portion of
the fin and study it with higher power. Find two kinds
of corpuscles in the blood: (1) red corpuscles (red only
when a number are seen together), very numerous, and
carried along in the center of the larger currents closely
packed together; and (2) white corpuscles, . . . not
very numerous, and usually seen trailing along the edges
of the blood currents, or escaping out into the tissues.’

The English sparrow (fig. 32).—As the English spar-
rows, which have spread over the whole country, are almost
universally held to be pests, the shooting of a few to serve
as specimens for the study of the external parts of a bird
may be looked on more leniently than the killing of other
birds should be. The habits of the live birds may be
studied as the pupils go and come from school.

Examine a dead specimen. Note the division of the
body into head, trunk, and appendages—namely, wings
and legs. Note that the sparrow is covered with feathers,
some long, some short, in some places thick and in others
thin, but all fitting together to form a complete covering
for the body. Only the bill and feet are exposed, and
these are covered in one case (bill) with a horny sheath,
and in the other (feet) with horny scales. The feathers
and the horny covering of bill and feet are simply modi-
THE SUNFISH AND THE SPARROW 59

 

 

Fic. 32.—English sparrows at a drinking-place;

 

 

note the black cheeks and

throat of the males. (One-half natural size; from life.)
60 FIRST LESSONS IN ZOOLOGY

fied portions of the skin. Of what uses are the feathers
to the bird?

The feathers are of several kinds or types, each of
which has a name. In the wings and tail are long, stiff
feathers called quill feathers; those which overlie the
whole body and bear the color pattern are called contour
feathers; the small soft ones which cover the body more
or less completely (being, however, mostly hidden by the
contour feathers) are called down feathers or plumules,
while, finally, the scattered, slender, soft, or stiff hair-like
ones, with the thin bare stem and small terminal tuft of
branches, are called thread feathers or filoplumes.

Pull a quill feather from the wing and examine it in
detail. Note the central stem or shaft, composed of two
parts, a basal hollow transparent quill, which bears no
web and by which the feather is inserted in the skin, and
a longer terminal four-sided part, the rachis, which bears
on either side a web or vane. Examine the vane with a
lens and see that it is composed of many narrow linear
plates called barbs, and that
each barb is fringed in turn
with smaller branches called
barbules. Finally, each
barbule bears many fine
barbicels or hamules, which
can be seen with a micro-
scope. The barbs compris-
ing the vanes are inter-
locked with each other (fig.
33), thus forming a true web
and giving the vanes, com-

 

Fic. 33.—Bit of bird’s feather, greatly
maynified; s, shaft; 4, barb; 4/, posed of small, weak parts,
Darbule; 4, hamule. (From = speci-
men.)

much strength and power
of resistance. Rub the
feathers from tip to base, and, examining the vanes with
THE SUNFISH AND THE SPARROW 61

the lens, find out what has happened ; now rub from base
to tip, and note, under a lens, the result.

Examine a plucked-out contour feather. How does it
differ from the quill feather? Can you understand its
structure from your study of the quill feather ? Note that
the tip of the feather is colored and marked while the
base is not especially patterned. Why is this? Ex-
amine a down feather. How does it differ in make up
from a quill feather? From a contour feather ? What
is the special use of the down feathers ? Finally, pluck
out one of the hair-like thread feathers from the base of
the bill and examine it with the lens to determine its
structure.

Make a careful drawing of each of the four kinds of
feathers, naming all the parts.

In classifying birds reference is made in the manuals
of classification to differences in the shape and character
of many parts of the body and to differences in the plumage
of various body-regions. To understand these references
it is necessary to become acquainted with the names
applied to these various small parts and regions, and so
in fig. 34 the names of them all are given.

Examine the bill or beak. It is composed of an upper
and a lower mandible or jaw; the meeting line of the
mandibles is called the commissure, and the corner of
the mouth is called the rictus; the bristles at the rictus are
the rictal bristles; the median ridge of the upper mandible
is the culmen, and the median keel of the lower mandible
the gonys. Note just above the bill two openings. What
are they? How are they connected with the mouth? Note
the eyes, and at the inner angle of each the delicate nictitat-
ing membrane, which can be drawn over the ball. Does
the bird have external ears? The names of the regions of
the head which are commonly referred to in describing its
markings will be learned from fig. 34.
,Culmen

62 FIRST LESSONS IN ZOOLOGY

Examine a wing; determine by reference to fig. 34 what
feathers compose the primaries, secondaries, tertiaries,

Upper mandible

‘Lower mandible

        
   
 

 

Forehead

-- Outer Toe

Fic. 34.—Outline of bird’s body, with names of external parts and regions.

(Hallux )

  
 
 
 

Heel joint (Suffrago)

Lateral rectrix

so
greater, middle, and lesser coverts. How many primaries
are there?) How many secondaries? At the bend of the

 
THE SUNFISH AND THE SPARROW 63

wing and lying partly over the upper greater coverts is a
tuft of short quills, the spurious quills ; underneath the
wing at its junction with the body are some long, narrow
feathers, the axillars.

Spread the wing out and note where the quill feathers
are inserted. Note how perfectly the feathers fit together
and overlap, both when the wing is outspread and when
folded. The wing corresponds to our arm and hand,
the primaries being inserted on the hand (in the bird
there is only one large finger, two very small ones not
showing except in the skeleton), the secondaries on the
forearm and the tertiaries on the upper arm. With what
part of the fish does the wing of the bird correspond?
If a cleaned and mounted skeleton of a bird can be had
for examination the bones of the wing should be studied
and drawn.

The names of the various regions of the trunk can be
learned by reference to fig. 34.

How many rectrices or tail feathers are there? What
is the use of the tail? Note the oil gland above the base
of the tail. What is the use of the oil? How is it put
on the feathers? Observe this in a chicken.

Examine a leg. It is composed of thigh, shank, and
foot, the foot comprising the long slender tarsus and four
toes with claws. What parts of the leg are feathered?
Note the covering on the unfeathered parts. What are
the toes well fitted for? There is much variety in the
shape and character of birds’ legs, including differences
in the length of the various parts, in the covering, in the
number and position of the toes, and in the size of the
claws. All these differences, as well as the many in the
shape and character of the bill, are correlated with habits,
especially the feeding habits of the birds, and offer a most
interesting subject for study. Special attention is given
this subject in Chapter XV.
CHAPTER VI

THE MOTIONS OF ANIMALS, AND THE SKEL-
ETON AND MUSCLES

Motions and locomotion.—Our attention is usually
first attracted to an animal by the movements it makes.
These are the plainest proof that it is alive. For the
animal itself the ability to move is essential to existence.
Most animals move in search of food, to escape from their
enemies, to find and build their homes, to seek their
mates, and care for their young. In the higher forms the
organs of motion constitute the great bulk of the body.
The shape and size of such an animal are determined
largely by these organs.

The heart and blood-vessels, the lungs and digestive
system, are principally concerned with supplying the
organs of motion with materials necessary for their
working, and by far the larger part of the work of the
sense organs and nervous system is to put these organs
into action, and to direct and control them. We can
see therefore that they have much to do with both the
structure and physiology of animals. Indeed the most
marked difference between animals and plants is the pos-
session by the former of the organs of motion and their
controlling organs, the sense organs, the brain and
nerves. True, plants have the power of motion and are
sensitive to light, heat, and other influences as are
animals, but to a far less degree.

64
THE MOTIONS OF ANIMALS 65

Among the movements made by animals, the moving
of the body from place to place, usually spoken of as lo-
comotion, generally requires the greatest energy or power.
The other motions are those of parts of the body, as the
arms, legs, head, etc. We shall here consider a few
examples of the motion of animals illustrating the
character of locomotion in different forms.

There are three different ways in which locomotion
takes place, that is, by swimming in water, crawling or
walking or leaping on some solid object, as the ground
or the trunk of a tree, and by flying in the air. In
each of these three cases the body must first be sup-
ported, then either pushed or pulled along or perhaps
both pushed and pulled.

In swimming the body is supported by the water. In
animals that swim it is either lighter than water, asin the
duck, or just as heavy or only a little heavier, as in fishes,
so that it is wholly or almost wholly held up by the
water, and the full power of the leg, fin, or tail used in
the motion can be devoted to pushing the animal along.
Animals crawling on the bottom in water also have very
little to do in holding up the body, the water supporting
them. But those that move on land or fly, with their
bodies immersed in air alone, have the body only very
slightly supported by the air. These animals must there-
fore devote energy to supporting the body as well as to
moving it along, and they have special means for this.

As already said the body is moved by pushes or pulls.
In by far the most cases motion results from pushes given
by a part of the body against something outside. Now
it is plain that air is a very poor. thing to push against as
compared with water or a solid. Naturally since water
is a liquid it gives way readily to a push, but its heaviness
offers much greater resistance to motion than does the air.
The solid ground, of course, offers most of all. Currents
66 FIRST LESSONS IN ZOOLOGY

in water and air are of peculiar help in this matter.
Water currents may carry an animal for great distances
without any work on its part; while air currents make it
possible for birds to soar with little effort. Flight by the
vibration of wings, as in birds and insects, requires the
greatest expenditure of energy, since the pushes against
the thin air must be made quickly and with great force and
be rapidly repeated to be effective for support and loco-
motion. Man in making locomotive machines, railway
engines, automobiles, steamships, etc., has met the
same conditions as the animals; but the difficulties of
aerial locomotion are so great that he has not yet been
successful in inventing a mechanism for it such as has
been developed in the birds.

The simplest and what may be called the most imper-
fect mode of locomotion is shown by the simplest ani-
mals. These, the Protozoa (see Chapter IX), are ex-
tremely minute, and mostly live in water. A single drop
of stagnant water may contain hundreds of them. Among
these simplest animals we can readily find forms illus-
trating at least four different modes of motion; all, how-
ever, are really but different forms of the same action, that
is, the contracting or shortening and thickening of a part
or the whole of the animal. In the Amceba (see Chapter
IX) the body is composed of a minute bit of soft, jelly-
like living substance called protoplasm, without any spe-
cial parts at all. By the varying contracting and relaxing
of the soft body portions of it are protruded and with-
drawn again, a slow and imperfect locomotion being
accomplished by this means (fig. 35). In the most rapidly
moving Amceba the motion is very slow, while in the slower
ones it would take some hours to proceed a single inch.

Some kinds of Protozoa show what is called streaming
motion. This is seen in forms in which the central por-
tion of the body protoplasm will flow along for a while in
THE MOTIONS OF ANIMALS 67

one direction, then stop and flow the opposite way. It
is not easy to understand the exact method by which this
motion is produced.

In some of the Protozoa, instead of the whole or a large
part of the body taking part in an ill-defined movement,

 

Fic, 35.—Ameba sp.; showing the forms assumed by a single individual
in four successive changes, (Greatly magnified; from life.)

there are definite organs of motion. Small, hair-like parts
of the body, called cilia or flagella, are extended into the
water and struck or pushed against it. Among the ciliate
and flagellate Protozoa we find some with the body cov-
ered all over with cilia, as in Paramcecium (fig. 36), and
some with only very definite cilia-covered areas, or even
with but one or two cilia, these being usually long and
68 FIRST LESSONS IN ZOOLOGY

whiplash-like. In some the cilia seem to be in constant
rhythmic motion, in others they seem to move only when
the animal wills it. Motion by the contraction of a fiber is
seen in the peculiar Protozoan called Vorticella (fig. 37).

 

 

 

 

 

 

Fic. 36.—Laramecium sp.; Fic. 37.— Vorticella sp.; one
buceal groove at right. individual with stalk coiled,
(Greatly magnified; from and one with stalk extended.
life. ) (Greatly magnified; from life.)

This animal has a tiny bell-like body on the end of a
slender stalk. The stalk is made up of an outer rather
firm elastic substance with a contractile fiber in the core.
When the fiber contracts the stalk is drawn up into a spiral
and thus becomes shortened,

Muscles and skeleton.—The living elements in the
body of the higher animals are small parts called cells,
THE MOTIONS OF ANIMALS 69

and all of the above-described kinds of motion are found
in some of these. But motion is produced mainly by the
contraction of fibers, which are grouped into masses called
muscles. In the higher groups of animals the great
mass of the body consists of muscles composed of con-
tractile fibers, which are to be thought of as modifications
of a fiber such as exists in the stalk of the Vorticella, one
of the smallest and simplest of living animals. It is as if
the contractile substance had appeared under different
forms, but having proved most useful in the form of fibers
as animals rose higher in the scale this form became very
extensively used.

In such forms as the hydroids and jellyfishes the con-
tractile fibers are not gathered together into such definite
muscles as in the higher animals, nor are there such well-
developed firm body-parts for the fibers to pull against.
These contractile fibers are only extensions of) certain
body-cells, as in Hydra (see Chapter IX), or form a more
or less scattered net-work, gathered into ill-defined bands
or sheets, as in the sea-anemones and jellyfishes. From
the starfishes and worms, through the crabs and insects,
the muscular parts become more and more definite in
form and prompt in action, and there appears more and
more perfect development of firm parts. Some of these
serve as points of attachment from which the muscles can
pull, and some act as levers to make a push on the
external water, earth, or air. The swift, strong, and
accurate motions of the insects and of the backboned
animals require rigid levers, firm points for levers to work
against, or fulcra, and other firm points for the attach-
ment of muscles from which to exert their pull. These
firm solid parts, the levers, fulcra, and attachment points
of muscles, constitute the skeleton of the animal body.

The skeleton of a backboneless or invertebrate animal
differs from that of a backboned or vertebrate one not in
7° FIRST LESSONS IN ZOOLOGY

the use made of it but in its arrangement and in the part
of the body from which it is mainly developed. The
skeleton of the invertebrate is developed from the skin,
and forms a hard casing over the whole or part of the
body. It is therefore called an exoskeleton. How this
outside skeleton serves as levers, fulcra, and points of at-
tachment may well be seen in the case of insects (fig. 38),

a

———

  

Se
H vit .
wT

: Vv.in.c.

Fic. 38.— Left middle leg Fic, 39.—Diagram of cross-section through
of cockroach, with exo- the thorax of an insect to show the muscles
skeleton partly — re- of the wings and legs; 4, heart; alc,
moved, showing mus- alimentary canal; v.#.c, ventral nerve
cles. (Much enlarged; cord; w, wing; 7, leg; m, muscles.
after Miall and Denny.) (Much enlarged; after Graber.)

or crayfishes. The wall of the thorax, or carapace
(fig. 39), is the central strong portion from which the great
pulls are exerted, while each joint of a leg is a lever, a
fulcrum for the next part, and a point of attachment for
muscles. The whole system of muscles is so arranged
inside the exoskeleton that the flying, crawling, and
swimming of the various animals, as well as the particular
THE MOTIONS OF ANIMALS 71

motions of the eyes, feelers, and respiratory organs are
well performed.

In the vertebrates the skeleton is mainly developed
from tissues within the body and is called in consequence
the endoskeleton. Even more than
in the invertebrates it is a system
(fig. 40) of levers, fulcra, and points
of attachment for muscles to work
with, and is as important a part of the
organs of motion as is the muscular
system itself.

: To illustrate the use of the skele-

Sea ton of a vertebrate we may examine
arm of man; to show the bones of the hind legs of a cat
how bones and muscle

act as levers, (After (fig. 41). The upper bone, the femur,

Jenkins.) is attached by a joint to the large
irregularly shaped bone called the ilium, which is firmly
bound to the backbone. Below the femur are two
bones, the largest, called tibia, being bound by a joint
to the femur. Below the tibia are a group of bones, the
tarsal bones, pretty
firmly fastened to-
gether. The largest
makes a joint with
the tibia. Each of
the four tarsal bones
toward the toes make a
a joint with a slender Fy. 41,—Skeleton of cat. (After Reighard
bone in the body of and Jennings.)
the foot. These are the metatarsals. At the end of
each metatarsal is a series of three bones which form the
skeleton of the toes. All of these bones together consti-
tute a system of levers which the muscles of the leg can
draw up in a somewhat folded position, and then
straighten out with quickness and force. Since during

 

 
72 FIRST LESSONS IN ZOOLOGY

such movements the toes rest on the solid ground, the body
is lifted and thrown forward. There are a number of
strong muscles which make the pulls for these motions,
but a single pair may be studied as an cxampile of the
method of attachment and action of all.

Fig. 42 shows the large muscles of the fore leg of a
cat. Each consists of a large central mass formed of the
muscular or contractile substance proper bound up into a
compact body by connective tissues, with strings or bands
of connective tissue at the ends fastening the muscular
mass to the bones. These fastenings
are tendons. When the muscular sub-
stance contracts it of course pulls on the
two tendonous ends. If one end of a
muscle in the hind leg is attached to
the hip-bone it cannot move, but the
one fastened to the tibia moves this
bone as a lever, with its fulcrum at the
end of the femur. The tibia is brought
toward the femur and we say that the

 

/g) limb is flexed. Another muscle in con-

  

7)}
y # tracting will act on the tibia as a lever
5 also, but it brings the tibia back again
Fic. 42.—Muscles on Into a straight line with the femur.
a Bee ne This motion is called extension. For
hard and = Jen- each part of the limb from hip to toe are
vie groups of muscles which flex and extend
that part, the bones being levers and fulcra and points of
attachment. Most of these levers are of the kind called in
mechanics levers of the third class. By them quickness of
motion is magnified. Thus by noting first what motions
an animal makes, and then, by dissection, examining the
muscles, the bones, and their points and means of attach-
ment, we may come to understand clearly the uses of
the muscles and skeleton in any animal.
THE MOTIONS OF ANIMALS 73

The plan of the skeleton in the vertebrates is the same
throughout the whole great group, which includes the
fishes, amphibians, reptiles, birds, and mammals. The
differences lie in the varying development of the differ-
ent parts and in the modification in the size and form of
these parts. The plan includes a central axial portion,
the spinal column, made up of a series of elements called
vertebre. In a completely developed skeleton, as that of
a cat (fig. 41), the groups of vertebre are the cervical,
i.e., those of the neck; dorsal, those to which the ribs
are attached; lumbar, just posterior to the dorsal; sacral,
the group to which the ilium is bound, and caudal or
tail vertebrae. In the higher vertebrates the vertebra
of the sacral group are fused into one bone, the sacrum;
while the caudal vertebre, posterior to the sacrum, are
fused into one or a few bones in animals without a tail and
in them named the coccyx. The bones of the spinal
column are firmly bound together, constituting a somewhat
flexible but very firm axis, to which the head and limbs
are attached and from which the main pulls on these parts
can be exerted. The head skeleton consists of a central
group of bones in front of the axial skeleton, being an
extension of it, and around it are placed the other bones
of the head. To the axial skeleton are attached two pairs
of limbs; an anterior pair, joined to the axis by a group
of bones known as the shoulder girdle, and a posterior
pair joined to the axis by the pelvic girdle. The leg of
the cat, already described, may be taken as a represent-
ative limb.

Now if we examine a series of vertebrate skeletons,
representative of the different groups from the lowest
forms of fishes through to the highest mammals, we can
see that notwithstanding the different forms and sizes of
the various animals and their different ways of locomotion
—swimming, flying, crawling, running, walking, and leap-
74 FIRST LESSONS IN ZOOLOGY

ing—they all make use of the same plan of levers, each
kind of animal, however, having it specially adapted
for its peculiar motions. To see this more clearly com-

 

Fic, 43.—Bones of fore limb of various backboned animals; A, horse;
B, bird; C, man; D, dog; £, fish; F, reptile.

pare the skeleton of the fin of a fish with the fore leg of

a lizard, the wing of a bird, the fore leg of a horse, the

fore leg of a dog, and the arm of man (fig. 43).

If we carefully remove the skin from the side of a
fish such as a black bass or sunfish, there is shown
a mass of flesh (fig. 44). The great bulk of this is
one large muscle, the contraction of which makes the
THE MOTIONS OF ANIMALS 75

body curve to the same side and thus gives a stroke of
the tail fin. A similar muscle on the opposite side pro-
duces a stroke in the opposite direction. These alternating
strokes are the propelling power which forces the fish
through the water. At the base of each of the other
fins are found a few small strips of muscle. These give
their varied and more gentle movements which keep the
body in any particular position and aid in directing its

 

Fic. 44.—Side view of a dogfish (shark) with a strip of skin removed to
show muscles. (After Parker.)

locomotion. About the head are other muscles which

move the jaws, eyes, and gill-covers.

If we take the skin from the side of a body of a dog
and dissect out all the muscles we find a large number of
well-developed ones. The great muscular mass on the side
of the fish’s body used for one or a few motions is replaced
in the dog by a great number of muscles used to produce
a number of various movements. The few comparatively
weak muscles of a ventral fin are replaced by the many
large, strong, and definite ones of the hind limb of the
dog, while the small group working the pectoral fin finds
its representative in the large and varied group moving
the fore leg.

Further differences are seen in comparing the head of
the fish with that of the dog, as well as in every other
part of the two bodies. These differences all show that
in the dog there is a separation of the muscular system
into more numerous and more definite forms of muscles,
with the possibility of more numerous and more accurate
motions than in the fish. If we compare the muscles
76 FIRST LESSONS IN ZOOLOGY

and bones of the human hand and arm with those of
the fore limb of other animals we find an advance in
complexity over the fin of a fish or the fore limb of a
salamander or even the fore leg of a dog, although all are
made up on the same plan and out of the same elements.
If we now go further and compare the organs of motion
in the human body with the means of motion in Amceba
we see what a wonderful advance the highest animal
exhibits over the lowest both in structure of the motor
organs and in the possibilities of movement.
CHAPTER VII

HOW ANIMALS TURN FOOD AND AIR INTO
FLESH AND ENERGY

Necessity of oxygen and food.—In the organs of
motion just studied the muscles and bones are only the
machinery for motion. They make use of energy but
cannot themselves provide it. Just as an engine and all
the wheels and levers connected with it make use of heat,
which is one of the forms of energy, to produce the needed
motions, so the muscles and bones make use of some form
of energy to produce the motions of the animal body.
In the steam-engine the special form used is heat, gen-
erated by the burning of coal, oil, or wood; by means of
this heat, which expands the steam, i.e., the vapor of
water, energy is applied to the piston in the form of a
push. The motion of the piston is passed over to the
wheels and levers of the shop, and by them are given all
the different directions and velocities required by the
different machines of that particular shop.

In the animal body the muscle is the engine, for in it
the energy is generated. In a way we do not yet ex-
actly understand this energy makes the muscular sub-
stance contract and give a pull on the tendon, with the
same effect as the push of the steam on the piston, that
is, to set the rest of the machinery, the bones, in motion.
The bones apply the motion in the way required for the
movement of the animal. A striking difference, how-
ever, between the animal body and a shop is this, that

77
78 FIRST LESSONS IN ZOOLOGY

while in even a very large shop there may be but one
engine generating energy to run all the different machines,
in the body every muscle is a separate engine, and one
bone may be connected with a number of them. Never-
theless the essential facts are the same in both cases.
The muscle-engine, like the steam-engine, produces a form
of energy and applies it to machines so as to lift weights
or to move things from place to place. But we learn in
physics that we can get any form of energy only by
changing some other form into the one desired. The
forms of energy are heat, light, electricity, chemical en-
ergy, and that of a body in motion. Now the only way
to get heat, for example, is by a change from one of the
others. We can make a piece of iron hot by striking it
with a hammer; here the energy of a moving body is con-
verted into heat. Or the energy of the electric current
may be converted into heat or motion. Man’s most com-
mon way of getting heat is to take coal, wood, or oil, and
apply some heat to start with, when the oxygen of the air
will unite with carbon and hydrogen, substances in the coal,
wood, or oil, to make two new substances, one of these
being carbon dioxide, the other water. This is chemical
action; it results in changing chemical energy into heat.
In ordinary language this union of oxygen with carbon or
hydrogen is spoken of as ‘‘ burning '’ or ‘‘ combustion.’

An animal cannot make the least motion without using
a certain amount of energy. And it has been shown by
investigation that the energy possessed by an animal
is derived from the chemical energy resulting from the
union of oxygen with the carbon, hydrogen, and nitro-
gen in other substances. The muscles are the engines
in which this energy is made use of for motion. This
brings us now to see how essential it is that the animal
should have in its body oxygen and substances for the
oxygen to combine with.
FOOD AND AIR TURNED INTO FLESH AND ENERGY. 79

The animal body, however, not only needs a constant
supply of the substances from which this energy may be
produced, but also a constant supply of those substances
which compose its body. In every young animal there
is a growth, an increase of size and weight, and in the
adult a constant replacing of body material. And by
far the greater part of an animal body is made up of just
those things, namely, oxygen, carbon, hydrogen, and
nitrogen, that are used in the supply of energy.

How animals breathe.—The animal gets its oxygen
from the free air, or from the air mixed with water, by a
process called respiration. It obtains from its food all
the other substances used. Food is prepared for use by
the process of digestion. Oxygen obtained by respiration
and the substances obtained from food are distributed
throughout the body by the process of circulation. We
may now consider the ways in which respiration, diges-
tion, and circulation are carried on among animals.

As to respiration, mention has been made only of its
service in providing the animal with oxygen. It has,
however, one other object. When oxygen combines with
carbon, carbon dioxide is formed; if this remains in the
muscle or other tissue cells it interferes with the activity
of those cells. It is therefore just as necessary for the
carbon dioxide to be removed as for the oxygen to be
supplied. Carbon dioxide, like oxygen, is soluble in water.
Blood, which is composed largely of water, and which can
carry the one serves also to carry the other. Further-
more, since carbon dioxide is made by a combination with
oxygen, it arises just where it can be carried away by the
very apparatus that has brought the necessary oxygen.
Thus the respiratory apparatus manages both the supply
of oxygen and the disposal of carbon dioxide.

The fundamental fact in the process of respiration is
that gases, whether free or dissolved in water, will readily
80 FIRST LESSONS IN ZOOLOGY

pass through a thin, moist membrane. Thus if a closed
sac made of thin membrane filled with water in which
carbon dioxide is dissolved be immersed in water in which
oxygen is dissolved, carbon dioxide will pass out of the
sac and oxygen into it until there is the same amount of
each outside and inside. If the water outside is con-
stantly replaced all the carbon dioxide will be finally
removed. If the oxygen inside the sac is constantly
used up and the supply outside is always renewed, oxygen
will be constantly going in and carbon dioxide going
out. This is just what happens in the living animal.
Animals get their oxygen from the air, of which it is a
part. The air may be free or dissolved in water. Carbon
dioxide is made in the cells of the body. Respiration
takes place through the membranes covering all or part
of the surface of the body. It requires the constant re-
newal of free air or water containing air on the outside,
and the constant passage of fresh blood on the inside sur-
face of the membrane. This end is attained in a variety
of ways among animals.

In the simplest forms, the Protozoa, where we have
the most primitive means of motion, we find also the
simplest means of respiration. The Amccba (see Chap-
ter IX) simply relies on its whole external surface for
breathing, the thin outside layer of the body acting as a
membrane through which the oxygen passes in and the
carbon dioxide out. During periods of activity the pro-
cesses protruding from the body increase the amount of
respiratory surface sufficiently to provide for the increased
respiration demanded by the activity. In ciliated forms the
cilia greatly increase the surface area and respiration is
further assisted by the constant contact of the moving
body with fresher water. Even in more complex animals,
the common earthworm and the larvic of some insects
for example, the whole external skin is sometimes the
FOOD AND AIR TURNED INTO FLESH AND ENERGY 81

only respiratory surface. Such animals have only sluggish
and weak motions however. Much increase in size and
activity make certain demands on the surface of the body
which unfit it for respiration. The hard covering of in-
sects, crabs, and other animals necessary in connection
with locomotion and for protection from injuries illustrate
this. Again, while in a minute form like Amceba, the
slight increase of surface attained by its protruded pro-
cesses answers the increased respiratory needs, the sur-
face of a large animal would fall far short of doing so,
because, according to a familiar law of physics, the mass
or bulk of a body increases as the cube of the diameter
while the surface increases only as the square. There-
fore the larger animals must have special respiratory sur-
faces with special respiratory apparatus to move the air
or water over these surfaces externally, and special cir-
culatory apparatus to move the blood over them internally.

Special respiratory surface is provided for in two ways.
One is by the extension of a portion of the surface exter-
nally; thus gills are formed. The other is by the exten-
sion of the surface within the body in the form of tubes,
as the trachez in insects, or of sacs, as the lungs in the
vertebrates. Water-breathers have gills and air-breathers
have trachee or lungs.

In crayfishes or crabs the gills have the form of feather-
like projections from one of the upper leg joints, and
extend up into a cavity formed by a projection of the car-
apace over the sides. It is interesting to note that these
animals have a paddle for bailing the water out of the gill
cavity, and that by it a constant current is kept flowing
over the gills. Fishes breathe by means of gills, of which
they have four pairs (fig. 45). These are placed on the
sides of the head and consist of minute projections of the
skin appearing as a fine red fringe. They are supported
by bony or cartilaginous arches. The heart lies close to
82 FIRST LESSONS IN ZOOLOGY

the gills and pumps the blood directly into and through
them into vessels that carry it all over the body. The
fish keeps a current of
water passing over its
gills. First it opens
the mouth, spreading
the gill covers, when
the water rushes in,
after which it closes
the mouth drawing the
Fic. 45.—Head of trout with gill cover bent Covers together so that
forward to show gills. (From specimen.) the water is forced back
over the gills. This operation is constantly repeated.
If the mouth of an active fish

like a sunfish is fastened open it
will die, since it can no longer
breathe. It must be added
that the fins of most fishes no
doubt aid somewhat in respira-
tion since they are well supplied
with blood and the skin on
them is very thin.

 

Insects are mostly air-breath-
ers. Many, the bee and dragon-
fly for example, show very great
activity, demanding much oxy-
gen. They have an elaborate
system of tubes, called trachee
(figs. 46, 47, and 48), which
penetrate every part of the

 

body, reaching in some cases
every muscle cell. These open lic. 46,—Diagram showing tra-

J : ; cheal system of a beetle; sf,
to the air by means of pairs spiracles: ¢r, trachew. (After
of small holes, called spiracles, Kolbe.)

in most of the body segments. Air is made to come in
FOOD AND AIR TURNED INTO FLESH AND ENERGY 83

and go out through these by an alternate contraction and
expansion of the body readily seen in a bee or dragon-fly
at rest. The walls of the trachee are in part supported
by a fine spirally wound elastic thread which keeps the
tubes always open to the air. The spiracles are often
guarded by little tufts of hairs, which being oily prevent

 

Fic. 47. Fic. 48,

Fic. 47.—Diagram of trachee in head of a cockroach; note branches to all
mouth parts and feelers; ¢, trachez or air-tubes. (After Miall and
Denny.)

Fic. 48.—Piece of trachea (air-tube) from an insect. (Photomicrograph
by Geo. O. Mitchell.)

water from entering easily, though oil will enter readily,
and a drop of oil running over the spiracles will quickly kill
an insect. Very fine dust will also choke up the spiracles
and smother it. Some ‘‘ insect powders ’’ act in this way.

The amphibians, which class includes frogs, toads,
and salamanders, are water-breathers during their young
life and in this period have gills. But early in the tad-
pole stage there develops by growth from a point in the
throat what is first a pouch, later a small pair of lungs,
which are soon put in use. By the time the animal
84 FIRST LESSONS IN ZOOLOGY

leaves the water the gills have disappeared and the
lungs are well developed. A few of the amphibians,
however, may retain the gills in addition throughout the
adult stage. Such forms live in water or in very moist
places. Moreover, most amphibians make use of the
skin, thin and moist like that of the frog, for respiration,
and thus have no necessity of great lung development.
The air-bladder of fishes has the position of a lung, but
is used ordinarily to regulate the weight of the body.
Still in a few forms, the garpike for example, it serves
sometimes as a lung.

In the higher vertebrates the exterior skin surface is
not adapted for respiration, which, together with the
generally greater activity of these animals, necessitates a
much greater development of the lungs. Thus instead of
the two simple lung sacs of the frog the lizard has a com-
plex double sac enlarged by tube-like extensions into the
body cavity. This arrangement gives a much increased
respiratory surface. In birds and mammals the extent
of surface is immensely increased. It is estimated that
the inner surface of a man’s lungs amounts to a thousand
square feet in area, or one hundred times the external sur-
face of the body. The windpipe gives off one large
branch to cach lung; these branches divide again and
again, the last divisions bearing on their ends very small
sacs of thin membrane about which is clustered a net-
work of capillary blood-vessels. Through the walls of
these small sacs the oxygen and carbon dioxide pass.

So far we have seen only how increase of surface is
brought about. Accompanying this we find improved
means for passing the air over the exterior and bringing
the blood to the interior surface. A frog or salamander
breathing quietly enlarges the mouth cavity by lowering
its floor, and the air comes in through the nostrils; this
air is then squeezed by the upward pressure of the floor of
FOOD AND AIR TURNED INTO FLESH AND ENERGY 85

the mouth, the valves in the nostrils close, and it is thus
pushed down into the lungs. The muscles in the walls
of the body now contract and squeeze upon the air in
the lungs, the nostril valves open, and the air is forced
out. This method is gradually improved upon in the
vertebrates until in the mammals we find a bony basket
of ribs and sternum, the thorax (fig. 49), containing the
lungs, with two sets of mus-
cles between the ribs, which
by their alternate contractions
and expansions first elevate
and extend the ribs, then
lower and draw them in, thus
enlarging and _ diminishing
the thoracic cavity. We find
further a muscular partition
in the thorax, the diaphragm,
separating it from the ab- heart, and diaphragm of mouse.
dominal cavity. When the  (f'0™ specimen.)

diaphragm, which is convex on the upper side, contracts
it lowers the floor of the thorax, thus enlarging the
thoracic cavity; the muscles in the walls of the abdomen
then contract and press upon the stomach, intestines,
and liver, pushing up the floor of the thorax and so
diminishing the thoracic cavity. Thus in two ways this
is enlarged, and in two ways diminished. As it enlarges,
the pressure of the outside air expands the elastic sacs of
the lungs; as it diminishes, the air is pressed out again.
Along with great increase of surface and great complexity
of mechanism for moving the air goes, as has been
pointed out, a perfecting of the circulatory apparatus for
bringing the blood to the respiratory surface, and a pro-
portionate complexity of the nervous system for producing
and regulating the movements necessary. It is to be
kept in mind, however, that the respiratory apparatus

 
86 FIRST LESSONS IN ZOOLOGY

only brings oxygen to the respiratory surface, and before
the real respiration at the tissue-cell can take place the
oxygen must be carried by the blood to the cell. This
process we shall later discuss under the head of circulation.

Now having seen how animals get the necessary oxygen
we may next inquire how they obtain and make use of
the equally necessary substances to be oxidized and to
build the body out of, that is, their food.

How animals obtain and digest food.
into the ways by which animals obtain and use food we
may consider the processes under three heads, obtaining
food, eating it, and digesting it. In obtaining food all
the sense and motor organs are employed, that is, the
instincts and ingenuity of the animal are brought into
play as well as the parts of its body. In eating it the
mouth is employed in mastication and the throat in swal-
lowing. Digestion is carried on by liquids secreted by
parts of the alimentary canal.

In examining

 

In the parts used for obtaining food we necessarily
find the greatest range of variation on account of the
great variety of food materials made use of. The food
of animals consists of other animals or plants. Of the
plants it may be leaves, stem, wood or bark, roots or
fruit or seeds. That particular part desired may be deep
in the ground, high in the air, or buried in a thick cover-
ing of its own. The plant sought may grow in a marsh,
on a plain, on a mountain, or immersed in the ocean.
It may be fit for food at a certain season only. To get
it the animal must have the necessary equipment of wings,
or legs, claws, beaks, teeth, etc., as well as eyes, ears, and
organs of smell, touch, and taste, besides some means for
searching out the places where it grows, selecting the
proper parts and deciding upon ways of securing these
parts. Acts like these last are performed by the nervous
system and arise from instinct or intelligence.
FOOD AND AIR TURNED INTO FLESH AND ENERGY 87

In the case of carnivorous animals where prey is to be
captured, the same adaptations must exist, being neces-
sarily even more complex than those demanded for the
securing of vegetable food. Some of the special adap-
tations of animals for food-getting are described in
Chapter XVII.

But food once obtained and ready to be eaten appears
under very many forms and there is accordingly great
variety of structure among the parts employed in eating.
Ameceba eats without a mouth. It extends any part of
its soft body over the little plant or animal it feeds upon.
In many Protozoa, however, there is a definite mouth-
place, as in Paramcecium, where the food particles are
gathered together in a little ball by the cilia, and then
pushed through the body-wall. The body of the fresh-
water hydra (see Chapter IX), incloses a digestive cavity,
the mouth being but an opening to this. In the higher
animals we find mouths arranged for cutting, filing,
sucking, crushing, gnawing, grinding, chiseling, pierc-
ing, sawing; in fact almost every device one could
think of for working in wood, bone, shell, flesh, liquid,
soft and hard material of many forms.

The study of the mouth parts of animals belonging to
one group shows how the same parts may take on such
different forms as to make very different kinds of appa-
ratus. For example among the insects, the bee (fig. 50),
mosquito (fig. 51), tiger-beetle, dragon-fly (fig. 52),
moth (fig. 53), and squash-bug, while exhibiting great
variety of mouth parts show each the same pieces, but in
each so changed in form as to make up a combination pe-
culiar to it. Among birds there is not so great a range of
difference; still, the various beaks and bills of chickens,
cranes, sparrows, ducks, curlews, hawks, cross-bills,
puffins, and horn-bills illustrate how one form may be
adapted to many operations. Birds do not use the mouth
88 FIRST LESSONS IN ZOOLOGY

for mastication. Where mastication is necessary there is
an expansion of the alimentary canal called crop or craw,
which acts as a reservoir for the hard seeds or grains,
and further along the gizzard, which with its strong
muscular wall and hard inner coat, assisted by the small
stones picked up in eating, sufficiently grinds up the

 

Mic, 50. Fic. 51.

lic. 5§0.—Head and mouth parts of honey-bee; note the short trowel-like
mandibles for moulding wax when building comb, and the extended
proboscis for sucking flower nectar. (Much enlarged; from specimen.)
Fic. §1.—Piercing and sucking beak of the mosquito (female) dissected to
show its parts. (Much enlarged; from specimen. )
food. Among mammals the same large extent of variety
in the mouth structure exists as among insects and birds.
Compare the teeth and other mouth parts of a rat,
beaver, cat, pig, horse, sheep, and man, noting how they
vary in number, size, and form, and then consider how
each is used in the process of cating.
To understand the process of digestion some knowledge
of the nature of food substances is necessary. In consid-
FOOD AND AIR TURNED INTO FLESH AND ENERGY 89

ering the production of energy and making of body mate-
rial we saw that the same substances provided for both.
In fact whatever the form of food, animal, or plant, the
elementary substances are the same, being conveniently
classified into two great groups, organic and inorganic
substances.

Inorganic food substances are water and certain minerals
of which common salt is one. Organic food substances
are of three kinds or groups. The first group, called the

 

Fic. 52.,—Mouth, with prehensile under lip, of young dragon-fly. (From
Jenkins and Kellogg. )

proteids, of which the white of egg is an example, forms
a large part of the tissues of animals; the second group
is made up of the fats and oils; the third, known as the
carbohydrates, consists of the starches and sugars.

Now digestion consists in changing all these substances
into soluble form so that they can be absorbed into the
body, circulate with the blood, if there be any, and then
pass into the living cells for their use. This change is
accomplished by certain liquids called digestive fluids.
The digestive apparatus varies like other parts of the ani-
mal organism, being most simple in some forms and very
complex in others. In Amceba the food particles are
retained in spaces in the cell until they are digested. So
in other Protozoa. The simple digestive cavity of the
hydra has been referred to (fig. 54). In the polyps and
jelly-fishes (see Chapter X), this cavity is extended, the
digestive surface being much increased by partitions,
FIRST LESSONS IN ZOOLOGY

Worms (figs. 55 and 56), crabs, and_ snails

 

 

  

Fic. §3.—Sucking proboscis of a sphinx

have a definite alimentary canal
with certain parts set apart for
special processes. In the verte-
brates the digestive apparatus
varies from a relatively simple
straight tube to the very long
and complex alimentary canal of
the cow (fig. 57). All these forms
depend much on the nature of the
food of the individual animal, and
the processes necessary to turn
it into body material.

To illustrate what complexity
of the digestive system may be
reached let us consider somewhat
in detail the structure of the ali-
mentary canal of a small mammal
a rabbit, for example. First is

 

Fic. 54.—Diagram of sec-
tion through a simple
polyp, Odea, showing

moth; in small figure the proboscis is digestive cavity 5 my
shown coiled up on the under side of the mouth-opening ; al.c, ali-
head, the normal position when not in use. mentary cavity, (After
(One-half natural size; from specimen.) Parker and Haswell.)

the mouth with its parts; the walls of the

mouth are

furnished with minute tube-like extensions or glands,
FOOD AND AIR TURNED INTO FLESH AND ENERGY 91

which secrete mucus to aid the animal in swallowing dry

substances. Other larger glands, the
salivary glands, empty into the mouth,
saliva being also necessary for the
purpose of swallowing. Behind the
mouth come the pharynx and gullet,
which together make a _ tube with
muscular walls which perform the
movements of swallowing. Both
pharynx and gullet are furnished with
numerous mucous glands. The gullet
leads to the stomach, an enlargement
of the alimentary canal acting mainly
as a reservoir. Its walls also are
filled with small glands secreting
gastric juice which makes proteid
foods soluble, that is, carries on the
proteid digestion. Next to the stom-
ach is the small intestine, a very long

tube in the first part-of which is ac- _

complished the digestion of starches
and fats. Its walls are lined with
numerous glands, and besides these,
two very large glands, the pancreas
and liver, pour into it large quantities
of liquid. The pancreatic juice di-
gests the starch and fat and also any
left-over proteids. The liver fur-

 

nishes the bile, but its functions being Fic. 55. — Common

mainly other than digestive, they need
not be discussed here.

The walls of the small intestine fur-
nish the principal surface for the absorp-
tion of digested food. This surface is

earthworm dissected
to show alimentary
canal, a straight and
nearly simple tube
through the middle.
(Natural size; after
Jordan and Kellogg.)

greatly increased by millions of small projections called
92 FIRST LESSONS IN ZOOLOGY

villi, in which are blood-vessels, and other absorbent ves-
sels for taking up the digested food. The small intestine
empties into the large intestine, which has an enlargement
called the cecum. The large intestine and the caecum
together form the last section of the alimentary canal and

 

 

Fic, 56. Fic. 57.

Fic. 56,—A flatworm (/7anarta) to show branched alimentary canal, a/c.
(About natural size; after Hatshek. )

Fic. 57.—Alimentary canal of a cow; a, rumen (left hemisphere); 4,
rumen (right hemisphere); ¢, insertion of ceso- phagus; d, reticulum;
e, omasum; /, abomasum; , duodenum; / and 7, jejunum and

Ay
ileum, 7, cecum; 4, colon with its various convolutions; /, rectum; the
whole canal about 150 fect long.
retain the remaining food substances for some time to
allow of more complete absorption of the digested foods.
The alimentary canal of the rabbit, with all its folding and
branchings into large glands and millions of small ones,
furnishes a surface for secretion and absorption very many
times the external surface of the body. In brief, the area
FOOD AND AIR TURNED INTO FLESH AND ENERGY 93

concerned with the taking in of food as well as of oxygen
is immensely increased in the higher animals.

We have now to consider that process which has to do
with carrying oxygen and food from the respiratory and
digestive surfaces to all parts of the body. This process
is the circulation, and the organs for performing it com-
pose the circulatory system.

How the blood circulates.—It has already been shown
that increase of size and activity in animals necessitates
blood and a means of circulating it through the body.
The uses of the circulation are: to bring oxygen from
the respiratory surface to every cell, to take carbon
dioxide from every cell to the respiratory surface, to
carry digested food substances from the absorbing surface
of the alimentary canal to every cell, and, further, to
remove from every cell the injurious and waste substances
formed by its activity to where they may be either ex-
creted from the body or otherwise disposed of. Circula-
tion is accomplished by the moving of a liquid through
a system of tubes and spaces channeling the whole body.

In the very smallest and most sluggish of animals there
is no circulatory system. In those which are of compara-
tively large size and very active, and which therefore need
a great amount of energy, much oxygen and food must
be supplied and a large amount of waste substance is
produced which must be removed. Here the circulatory
system is found to be highly developed and to work with
great efficiency.

In Amceba, because of its small size and the constant
flowing of the body-substance there is no circulatory sys-
tem. In some Protozoa the contents of the body-cell
seem to have a definite movement, but there are no such
organs as heart and blood-vessels. In most animals we
find blood and a system of tubes and spaces for it to circu-
late in. In some, as the insects (fig. 58), only part of the
94 FIRST LESSONS IN ZOOLOGY

circulatary system consists of definite tubes; these open
into loose ill-defined spaces in the body-cavity. In such
the blood is moved gradually throughout the animal, but
not so definitely and quickly as in others
where the blood runs in definite vessels.
In the earthworm there is no such heart
as in higher animals, but the blood-
vessel along the dorsal line and some
of its branches around the sides have
muscular walls and ‘‘ beat’? by a wave of
contraction running toward the head. In
insects the dorsal blood-vessel beats in
the same way, but generally more vigor-
ously. In the young larva of a mosquito
or nymph of a May-fly with transparent

 

Fic. 58.—Diagram ; :
of circulatory skin the beating can be easily seen under

system of young le soy:
dragon-y; inthe microscope. In molluscs there is a

middle is the well-developed heart; it can be well seen

chambered dor- ,

sal vessel or heart in the fresh-water mussel. The crustacea

with single ar- alsq have a heart. This can be seen at

tery; arrows in- ; :

dicate direction Work in a water-flea under the microscope,

of blood currents. ale i

(After Kolbe.) OF CaN be readily demonstrated inacrab or

crayfish killed with chloroform or ether.

In vertebrates the blood circulates in a definite system
of tubes through which it is pumped bya heart. The
fishes (fig. 59) have the heart consisting of two parts, with
muscular walls, a single auricle and a single ventricle.
The auricle receives the blood pouring from all the tissues
of the body through the veins. It contracts and forces
the blood into the ventricle. This then contracts and
drives it into a short vessel called the ventral aorta,
which gives off a branch artery for each gill-arch. The
gill-arteries divide up into capillaries in the gills, whence,
after aeration, the blood is gathered by another artery and
carried to the dorsal aorta, from which branch arteries
FOOD AND AIR TURNED INTO FLESH AND ENERGY. 95

distribute it to the capillaries of the general body-tissues.
From these it is gathered by the veins and carried back
to the auricle to begin again. In the course of circu-
lation the blood reaches every part of the body, picking
up certain substances here, leaving others there, thus
accomplishing the results already pointed out as the
objects of the circulation.

In the circulation of the higher vertebrates the most
striking difference from that of the fish is in the structure

      

Ss AE
PRY CRE
—- ae oS iS

=

 
  

Fic. 59.—Diagram of circulatory system of a fish; v, ventricle; a, auricle.
(After Parker and Haswell.)

of the heart, which adapts the circulation to lungs instead
of gills, and in the more perfect control and regulation
of the action of heart and blood-vessels by the nervous
system.

The circulation of a gilled frog tadpole is on the same
plan as that of a fish. In the adult frog, however, there
is no longer a circulation through gills but one through
the lungs. Moreover, the adult has two auricles instead
of one (fig. 60). Of these the right receives the blood
from veins draining the tissues, the other blood from the
lungs. All this blood, however, is thrown together into
the one ventricle, from which, mixed as it is, it is sent out
both to the lungs and to the tissues through arteries.

In reptiles there are two auricles, as in the frog, and a
partition partially separates the ventricle into halves (fig.
61), so that the blood coming from the tissues is kept
96 FIRST LESSONS IN ZOOLOGY

partly separate from that out of the lungs. This separa-
tion allows the blood from the lungs to be sent to the
tissues without much mixing with the impure blood from
the tissues. In birds and mammals the separation of the
two halves of the ventricle is complete, the blood from
the lungs being sent out unmixed to the tissues and that
from the tissues returned without delay to the lungs.
Fig. 62 gives the plan of the circulation in the mammals.

ra la
Yv viv
Fic. 60.—Diagram of heart of Fic. 61.—Diagram of heart of
amphibian; 7.a, right auricle; a reptile; 7,a, right auricle;
Z.a, left auricle; v, ventricle. /.a, left auricle; 7,7, ventricles,
(After Ritzema-Bos.) (After Ritzema-Bos, )

It shows how the blood is driven through the lungs by a
special pump, the right ventricle, which is devoted to
that purpose alone. It also makes clear how the blood is
made to pass from the left ventricle to all parts of the body
(fig. 63). It may be asked how, since the blood remains
in vessels during circulation, the tissue-cells receive any-
thing from it. The blood as such does not reach the tissue-
cells. These are surrounded by a liquid, called lymph,
which fills the spaces between them. The capillary
blood-vessels run through this liquid and may not actu-
ally touch the cells themselves at all, or at only a few
points. The walls of the capillaries being very thin,
however, the substances needed by the cells diffuse from
the blood through the walls into the liquid and thence to
the cells themselves. On the other hand, substances from
FOOD AND AIR TURNED INTO FLESH AND ENERGY 97

the cells—carbon dioxide and other waste matters—diffuse
into the liquid and from this to the blood through the
capillary walls. In fact each tissue-cell feeds, like cer-
tain one-celled animals, by absorption from a liquid

Y

10

ThastiaaR

   

I

\\ Wj
® yw iS

Ss

 

FIG, 63.

 

Fic. 62.—Diagram of the circulation of the blood in a mammal; a, auricles;
4, lung; /, liver; ~, portal vein bringing blood from the intestine; 7,
ventricles; the arrows show the direction of the current; the shaded

(From Kingsley.)

vessels carry venous blood, the others arterial blood.
Frc. 63.—-Heart of cat, dorsal view; a, right ventricle; 4, left auricle; c,
right auricle; d, vena cava inferior; ¢, vena cava superior; /, aorta.

(After Reighard and Jennings. )

medium, but by means of the circulation this liquid has a

prepared food constantly brought to it.

We may ask how the blood carries the oxygen. In
the vertebrates part of the blood consists of little bodies
called the red corpuscles. The color of these is due to
a chemical substance called hemoglobin. This has the
98

FIRST LESSONS IN ZOOLOGY

capacity of absorbing oxygen at the lungs and of giving

 

Fic. 64.— Lower fore-
leg and foot of cat,
showing arteries
(dotted lines), veins
(black lines), and
nerves (thin lines).
(After Reighard and
Jennings. )

it up to the tissues.

The blood of vertebrates and of
many invertebrates possesses a re-
markable property that should be
noticed, that is, of forming a jelly-
like mass called a clot when a vessel
is broken. In other words, it is
able to close the opening with a
solid plug made up of its own sub-
stances.

In higher vertebrates there is a
very perfect regulation of the heart-
beat, and of the narrowing or enlarg-
ing of the small by the
influence of the nervous system on
their muscular walls. By this means
and the peculiar structure of vein and
arteries, and the use of valves, the
flow of blood is nicely regulated to

arteries

the needs of each part of the body during its activity.
CHAPTER VIII.

HOW ANIMALS KNOW THINGS AND CONTROL
THEIR MOTIONS.

Thus far we have considered the mechanisms animals
have for motion and for obtaining oxygen and food. <A
more difficult but more interesting subject is how motions
take place in the animal, how they are guided, how they
are stopped, in short, how the whole conduct of the life of
the animal is carried on. To understand better what
these processes consist of, let us consider as an example
the life of a common bird. We know that after hatching
from the egg it takes food, learns the notes of the parent
bird, learns to fly, learns to fight or to avoid enemies, all
these including motions guided by sight, hearing, touch,
and smell. On the approach of winter it migrates to the
south; in spring it returns, chooses a mate, builds a nest,
and rears young to which it teaches in turn the ways of
bird life. While the full explanation of these processes
is far from being reached, and while we cannot here dis-
cuss them at length, yet we may at least examine some
of the parts ot the body specially concerned with these
processes. In the higher animals they are determined
and directed by means of the sense-organs and the ner-
vous system. In vertebrates the special senses, as they
are called, are those of sight, hearing, smell, taste,
touch, cold, heat, and one called the muscular sense.
A part of the eye known as the retina is specially

99
100 FIRST LESSONS IN ZOOLOGY

sensitive to light; in the internal ear there are certain
cells which are affected by sound vibrations; in the nasal
passages there is a region in which are cells sensitive
to odors; in the skin of the tongue are cells that react
to sweet, sour, and bitter liquids; in various parts of the
skin are cells sensitive to pressure, heat, and cold. These
different kinds of cells affected by different influences are
called sense-cells.

Now what the animal sees, hears, touches, etc., deter-
mines its motions, and we find that the sense-cells are

 

Fic, 65.—Central nervous system of a dog. (After Ritzema-Bos.)

connected with the muscles by means of the nervous
system. Through this connection light, heat, sound, etc.,
guide muscular action. For example, the hawk’s eye is
connected through the nervous system with the wing and
leg muscles of the bird, and by this means the wings and
legs may be made to make the motions necessary to catch
the chicken. To understand the makeup of the nervous
system, that of some small vertebrate should be examined
in connection with the following description.

The central nervous system.—The nervous system ofa
vertebrate (fig. 65), consists of a central portion, the brain
(fig. 66), and spinal cord, from which branches called
nerves extend in pairs; the nerves then branch and branch
again until their divisions reach every part of the body in
HOW ANIMALS KNOW THINGS 10]

the shape of very numerous white threads, too small to
be detected by the naked eye. These very small nerve-
threads or fibers end at last in connection with certain of
the tissue-cells. All the sense-cells of the retina, ear,
nose, tongue, and skin are con-
nected with minute nerve-fibers
as are also all the muscle-fibers.
Now all the nerve-fibers from both
sense-cells and muscle-cells run I
to the central portions of the
nervous system, the brain and
spinal cord, and are there in some
way definitely connected with one
another, thus making pathways
over which everything that affects
the eye, ear, and other sense-
organs may affect the muscles. Vv

The nervous system of all ver- ies oka eee
tebrates is on the same general bulbs; Z/, cerebral hemi-
plan, being, however, less com- Sphere cor Bellamy

: medulla oblongata. (After
plex in the lower forms. All  Reighard and Jennings.)

   

  
 

animals with a definite nervous system have nerve-fibers
connecting both sense-cells and muscle-cells with
certain central parts. They differ, however, in the
arrangement of these parts. And since they differ also
in muscular arrangement, and in the kind and position of
the sense-organs, the arrangement of the nerve-fibers
connecting muscles and sense-organs with these central
parts differs accordingly.

In the worms, crustacea, and insects, which have much
the same body-plan, the central nervous system (figs. 67
and 68), consists ofa chain of ganglia (small nerve-centers)
along the ventral portion of the body, this chain being con-
nected at the anterior end by a cord on each side of the
gullet, with a large head ganglion which stands in the
1o2 FIRST LESSONS IN ZOOLOGY

position of the vertebrate brain. Jn the starfishes and sea~-
urchins, the central nervous system has the form of a ring
with radiating branches, but with no head ganglia. In
sea-anemones and jellyfishes it is somewhat similar, but is
less distinctly set apart from the other tissue-cells. In
the one-celled animals we recognize no trace of a

 

Fic. 67.—Nervous system of the hvuse-fly, the central nerve-cord and
ganglia lie in the ventral (under) part of the body. (After Brandt.)
Fic. 68.—Nervous system of a midge (CAzronomus); note the separation of

all the ganglia. (After Brandt.)

nervous system any more than we do of a muscular or
bony system.

In comparing the nervous systems of various animals
as we have their muscular, bony, and circulatory systems
we find the same variety and progressive degree of
development holding true. In Amceba the whole cell is
in a weak way sensitive to light, heat, jars, odors, acids,
alkalis, and the various other things that affect the sense-
organs of higher animals. The cell as a whole conducts
the effects of these to all its parts and the response of the
animal is slow and indefinite.
HOW ANIMALS KNOW THINGS 103

As we proceed higher in the animal scale we find a
gradual grouping in definite positions of a number of
cells that are specially sensitive to the different influences
acting on the organisms, and along with this definite groups
of muscular cells and definite nerve pathways for impulses
to pass from the sensitive to the motor cells, and more
and more complex connections of groups with groups.
In the highest organisms we have sense-organs which

Sunfish. Toad, Snake. Sparrow. Mouse.

 

Fic. 69.—Diagram of brains of vetebrates; O/f. L., olfactory lobes; Cor.,
cerebrum; AZd, Br., midbrain (optic lobes); Céé., cerebellum; Aled. O4.,
medulla oblongata; S?. Ca@., spinal cord. (From specimens.)

make us exactly acquainted with the outside world; we
have brain, spinal cord, and nerves, which receive the
impulses from these and turn them through the muscles
into all the motions our bodies are capable of; besides
we have all those wonderful processes included under
what we call instinct, memory, and reason.

The special senses and their organs.—The organs
of sight, the eyes, are the only organs of special sense
generally conspicuous and unmistakably recognizable
when present. In the vertebrates the eyes, ears, nose,
and taste organs are always situated on the head, but
in the invertebrates the sense-organs corresponding to
these are often scattered over the body, and certain other

 
104 FIRST LESSONS IN ZOOLOGY

organs are found which from their structure seem to be
sense-organs although we are by no means sure what
kind of sense they serve.

In some of the lower animals, as the polyps, there are
on the skin certain sense-cells, either isolated or in small
groups that are not limited to a single special sense.
They seem to be stimulated not alone by the touching of
foreign substances, but also by warmth and light. These
simple sense-cells from which the more complex or special
ones may develop are called primitive or generalized
sense-organs.

The tactile sense or sense of touch is the simplest
and most wide-spread of the special senses, with the
simplest organs. The special organs are usually simple
hairs or papilla connecting with a nerve. They may be
distributed pretty evenly over most of the body or may
be mainly concentrated upon certain parts in crowded
groups. Many of the lower animals have projecting
parts, like the feeling tentacles of many marine inverte-
brates, or the antenna (feelers) of crabs and insects,
which are the special seat of the tactile organs. Among
the vertebrates the tactile organs are either like those of
the invertebrates, or are little sac-like bodies of connec-
tive tissue in which the end of a nerve is curiously folded
and convoluted. These little touch-corpuscles (fig. 70)
lie in the cell layer of the skin, covered over thinly by
the cuticle. Sometimes they are simply free, branched
nerve-endings in the skin. In either case they are
especially abundant in those parts of the body which
can be best used for fecling. In man the finger-tips are
thus specially supplied, in certain tailed monkeys the tip
of the tail, and in hogs the end of the snout.

The taste organs are much like the tactile organs ex-
cept that the special taste cell must be exposed, so that
small particles of the substance to be tasted can come
HOW ANIMALS KNOW THINGS 105

into actual contact with it. The taste organs (fig. 71)
of man and the other air-breathing animals are located
in the mouth or on the mouth parts. It is also necessary
that the food substance to be tasted be dissolved.. This
is accomplished by the fluids poured into the mouth from
the salivary glands. With the lower aquatic animals it
is not improbable that taste organs are situated on other
parts of the body besides the mouth, and that taste is

 

Fic. 70. Fic. 71.

Fic. 70,—Tactile (touch) corpuscle of the skin of man; 7, nerve. (Greatly
magnified; after Kélliker. )

Fic. 71.—Papilla with taste buds (4.4) from tongue of a calf. (Greatly
magnified; after Loven.)

used not only to test food substances but also the chem-
ical character of the fluid medium in which they live.
Smelling and tasting are closely allied, the one testing
substances dissolved, the other substances vaporized.
The organs of the sense of smell are, like those of taste,
simple nerve-endings in papillz or pits. By smell ani-
mals can discover food, avoid enemies, and find their
mates. With the strictly aquatic animals the sense of
smell is probably but little developed. There is little
opportunity for a gas or vapor to reach them, and only
as gas or vapor can a substance be smelled. With
these animals the sense of taste must take the place
of the olfactory sense. But among the insects, mostly
terrestrial animals, there is an extraordinary develop-
ment of the sense of smell. It is indeed probably
their principal special sense. Insects must depend on
106 FIRST LESSONS IN ZOOLOGY

smell far more than on sight or hearing for the dis-
covery of food, and for becoming aware of the pres-
ence of their enemies and the proximity of their mates
and companions. The organs of smell of insects are
situated principally on the antenne or feelers (fig. 72),
a single pair of which is borne
on the head of every insect.
That many insects have an ama-
zingly keen sense of smell has
been shown by numerous experi-
ments, and is constantly proved
by well-known habits. If a small
bit of decaying flesh be inclosed
in a box so that it is wholly con-
cealed, it will nevertheless soon
be found by the flies and carrion
beetles that either feed on carrion
or must always lay their eggs in
decaying matter so that their
carrion-eating larva may be pro-
, ; vided with food. In Jordan and
so a set laa Kellogg’s ‘*Animal Life’’ is
the terminal three seg- given the following illustration
ments enlarged and flat of the remarkable sense of smell

 

tened, and — bearing

ae ce possessed by certain insects: ‘‘ In
ve antenna thus serving A : :

as an olfactory organ. the insectary at Cornell University,
(Much enlarged; photo- 4 fey years ago, a few females of
micrograph by Geo, O. "

Mitchell.) the beautiful Promethea moth were

inclosed in a box, which was kept inside the insectary
building. No males had been seen about the insectary
nor in its immediate vicinity, although they had been
sought for by collectors. A few hours after the beginning
of the captivity of the female moths there were forty male
Prometheas fluttering about over the glass roof of the
insectary. They could not sce the females, and yet had
HOW ANIMALS KNOW THINGS 107

discovered their presence in the building. The discovery
was undoubtedly made by the sense cf smell. These
moths have very elaborately developed antenne, finely
branched or feathered, affording opportunity for the ex-
istence of very many smelling-pits.’’

Hearing is the perception of certain vibrations of bod-
ies. These vibrations give rise to waves—sound-waves
as they are called—which proceed from the vibrating
body in all directions, and which, coming to an animal,
stimulate the special auditory or hearing organs, which
transmit this stimulation along the auditory nerve to the
brain, where it is translated as sound. These sound-
waves come to animals usually through the air or, in the
case of aquatic animals, through water, or through both
air and water.

The organs of hearing are of very complex structure in
the case of man and the higher vertebrates. Our ears
(fig. 73), which are adapted
for perceiving or being stimu-
lated by vibrations ranging from
16 to 40,000 a second—that
is, for hearing all those sounds
produced by vibrations of a
rapidity not less than 16 to a
second nor greater than 40,000
to a second—are of such com- Fic. 73.—Diagram of human
plexity of structure that many ear; 9, external opening; 4,

‘3 bones of the ear; 4, labyrinth;
pages would be required for c, cochlea or ‘snail shell” ;
their description. But among Cee HERVE Eee
the lower or less highly organ-
ized animals the ears, or auditory organs, are much

 

simpler.

In most animals the auditory organs show the com-
mon characteristic of being wholly composed of, or hav-
ing, as an essential part, a small sac filled with liquid in
108 FIRST LESSONS IN ZOOLOGY

which one or more tiny spherical hard bodies called
otoliths are held. This auditory sac is formed of, or
lined internally by, auditory cells, specialized nerve-cells,
which often bear delicate vibratile hairs. Auditory or-
gans of this general character are known among the
polyps, the worms, the crustaceans, and the molluscs.
Recent studies seem to show that the otoliths have a
special use as organs which help the animal to keep its
equilibrium. In the common crayfish the ‘‘ears’’ are
situated in the basal segment of the inner antenne or
feelers. They consist each of a small sac filled with
liquid, in which are suspended several grains of sand or
other hard bodies. The inner surface of the sac is lined
with fine auditory hairs. The sound-waves coming
through the air or water outside strike against this sac,
which lies in a hollow on the upper or outer side of the
antenna. The sound-waves are taken up by the con-
tents of the sac and stimulate the fine hairs, which in
turn give this stimulus to the nerves which run from them
to the principal auditory nerve and thus to the brain of
the crayfish. Among the insects other kinds of auditory
organs exist. The common locust or grasshopper has
on the upper surface of the first abdominal segment a
pair of tympana or ear-drums (fig. 74), composed simply
of the thinned, tightly-stretched chitinous cuticle of the
body. On the inner surface of this ear-drum there are a
tiny auditory sac, a fine nerve leading from it to a small
auditory ganglion lying near the tympanum, and a large
nerve leading from this ganglion to one of the larger
ganglia situated on the floor of the thorax. In the crick-
ets and katydids, insects related to the locusts, the audi-
tory organs or ears are situated in the fore legs.

Certain other insects, as the mosquitoes and_ other
midges or gnats, undoubtedly hear by means of numerous
delicate hairs borne on the antenn. The male mosqui-
HOW ANIMALS KNOW THINGS 109

toes have many hundreds of these long, fine antennal
hairs, and on the sounding of a tuning-fork they have
been observed to vibrate strongly. In the base of each
antenna there is a most elaborate organ, composed of fine
chitinous rods, and accompanying nerves and nerve-cells

 

Fic. 74.—The auditory organ of a locust (Afelanoplus sp.). The large
clear part in the center of the figure is the thin tympanum, with the
auditory vesicle (small black pear-shaped spot) and auditory ganglion
(at left of vesicle and connected with it by a nerve) on its inner surface.
(Greatly magnified; photomicrograph by Geo. O. Mitchell.)

whose function it is to take up and transmit through the

auditory nerve to the brain the stimuli received from the

external auditory hairs.

Concerning the sense of sight and the seeing organs the
following brief discussion is taken from Jordan and Kel-
logg’s ‘* Animal Life”:

‘Not all animals have eyes. The moles, which live
underground, insects and other animals that live in caves,
and the deep-sea fishes which live in waters so deep that
110 FIRST LESSONS IN ZOOLOGY

the light of the sun never comes to them, have no eyes at
all, or have eyes of so rudimentary a character that they
can no longer be used for seeing. But all these animals
have no eyes or only rudimentary ones because they live
under conditions where eyes are useless. They have lost
their eyes by degeneration. There are, however, many
animals that have no eyes, nor have they or their ances-
tors ever had eyes. These are the simplest, most lowly
organized animals. Many, perhaps all eyeless animals,
are, however, capable of distinguishing light from dark-
ness. They are sensitive to light. An investigator
placed several individuals of the common, tiny fresh-water
polyp (Hydra) in a glass cylinder the walls of which were
painted black. He left a small part of the cylinder un-
painted, and in this part of the cylinder where the light
penetrated the Ilydras all gathered. The eyeless mag-
gots or larva of flies, when placed in the light will wrig-
gle and squirm away into dark crevices. They are con-
scious of light when exposed to it, and endeavor to shun
it. Most plants turn their leaves toward the light; the
sunflower turns on its stem to face the sun. Light seems
to stimulate organisms whether they have eyes or not,
and the organisms either try to get into the light or to
avoid it. But this is not seeing.

‘©The simplest eyes, if we may call them eyes, are not
capable of forming an image or picture of external objects.
They only make the animal better capable of distinguish-
ing between light and darkness or shadow. Many lowly
organized animals, as some polyps, and worms, have cer-
tain cells of the skin specially provided with pigment.
These cells grouped together form what is called a pig-
ment-fleck, which can, because of the presence of the pig-
ment, absorb more light than the skin-cells, and are more
sensitive to the light. By such pigment-flecks, or eye-
spots, the animals can detect, by their shadows, the passing
HOW ANIMALS KNOW THINGS III

near them of moving bodies, and thus be in some measure
informed of the approach of enemies or of prey. Some
of these eye-flecks are provided
not simply with pigment but
with a simple sort of lens that WwW
serves to concentrate rays of We WN
light and make this simplest :

 
    
       

sort of eye even more sensitive p,. 36. Ghaple eye oF &
to changes in the intensity of jellyfish. (Greatly magni-
Vehete fied; after Hertwig.)
ight (fig. 75).

‘Most of the many-celled animals possess eyes by
means of which a picture of external objects more or less
nearly complete and perfect can be formed. There is

  

Fic. 76.
Fic. 76.--Diagram of vertebrate eye; ¢, choroid; 2, iris; /, lens; 2, optic
nerve; 7, retina; s, sclerotic. (From Kingsley.)
Fic 77.—Part of cornea, showing facets, of the compound eye of a horse-
fly (Zherioplectes sp.). (Greatly magnified; photomicrograph by
Geo, O. Mitchell.)

great variety in the finer structure of these picture-forming
eyes, but each consists essentially of an inner delicate or
sensitive nervous surface called the retina, which is stim-
ulated by light, and is connected with the brain by a large
optic nerve, and of a transparent light-refracting lens
lying outside of the retina and exposed to the light.
Il2 FIRST LESSONS IN ZOOLOGY

These are the constant essential parts of an image-form-
ing and image-perceiving eye. In most eyes there are
other accessory parts which may make the whole eye an
organ of excessively complicated structure
and of remarkably perfect sceing capacity.
Our own eyes (fig. 76) are organs of ex-
treme structural complexity and of high
development, although some of the other
vertebrates have undoubtedly a keener
and more nearly perfected sight.

‘*The crustaceans and insects have
eyes of a peculiar character called com-
pound eyes (figs. 77 and 78). In addi-
tion most insects have smaller simple
eyes. Each of the compound eyes is
composed of many (from a few, as in
certain ants, to as many as twenty-five
thousand, as in certain beetles) eye ele-
ments, each eye element seeing inde-

 

pendently of the others and seeing only a
Fic. 78.—Section
through a few
facets and eve the whole eye. All the small parts of

elements of the :
compound eye of the external object seen by the many

very small part of any object in front of

3 es ae tor- distinct eye clements combine so as to
nea ACCES? 656, : & 5 ‘
crystallinecones; form an image in mosaic, that is, made
fy pigments 7 up of separate small parts of the external
retinal parts; 0.7, 5

optic nerve. object. If the head of a dragon-fly be
(Greatly mayni-
fied; after [x-
ner.) or more of the whole head is made up

of the two large compound eyes, and with a lens it may
be seen that the outer surface of each of these eyes is

examined it will be seen that two-thirds

composed of many small spaces or facets, which are the
outer Ienses of the many cye clements composing the

whole eye.’’
PART Ill.

VARIOUS KINDS OF ANIMALS, AND
THEIR: LIFE.

CHAPTER IX.

THE AMCGEBA, HYDRA, AND OTHER SIMPLE
ANIMALS.

Although the animals we know best are pretty large,
and the tiny midges which dance in swarms in the air,
and the little mosquito wrigglers which squirm in stag-
nant water seem to us among the smallest of animals, as
a matter of fact there are thousands of kinds much smaller
than the smallest we can see. Almost all of these minute
animals live either in fresh water or the ocean, and
among them are the simplest kinds in the entire animal
kingdom. Because they are too small to be seen by the
unaided eye they can be studied only with the compound
microscope. If the schoolroom is provided with one,
bring in a little water, together with a few small sticks or
decaying leaves, from the bottom of some stagnant pool,
and examine a drop or two of it under the microscope.
It will prove to be a tiny ocean world inhabited by mini-
ature animals and plants. In it will be found a few larger
animals preying on the smaller ones. There is sudden and
violent death here, and births, and locomotion and food-
getting and growth, and all the activities and functions of

113
114 FIRST LESSONS IN ZOOLOGY

life which we are accustomed to see in the more familiar
world of larger animals.

Ameba.—The simplest and one of the smallest of all
known animals is Amoeba. If in a drop of stagnant
water taken from the slime on a dead leaf or stick from
the bottom of the pool you discover a microscopic, nearly
transparent, granular, jelly-like speck which slowly but
constantly changes its form then you have an Amceba.
Its whole body is nothing but a tiny, formless, viscous
speck of protoplasm. It is an animal without legs or
feelers, skeleton or muscles, without mouth or stomach,
eyes or brain; without heart or lungs, nerves or blood,
and yet is as truly an animal as a horse, and as capable
as the horse of performing, although in the simplest pos-
sible way, all the processes necessary to life, such as
taking in and digesting food, taking up oxygen and giv-
ing off carbon dioxide, feeling and moving about. Its
whole body is composed of a single one of the units
called cells, thousands and millions of which are included
in the body of any one of the larger and more familiar
animals.

Having found an Ameeba note its irregular shape and
observe its mode of moving (fig. 79). How does it
move? The little processes which stick out in various
directions are called false feet or pseudopodia. They are
simply parts of the body protoplasm. Has Amceba a
definite body-wall? Do the false feet protrude from cer-
tain parts of the body only? Inside note a clear globular
spot which contracts and expands or pulsates more or
less regularly. This is the contractile vacuole. Note the
small granules which move about in the body. These
are food particles which have been taken in through the
body-wall. Note how the false feet flow about food parti-
cles (tiny one-celled plants or other bits of organic mat-
ter) in the water. When these are surrounded by the
THE AMCEBA, HYDRA, AND OTHER SIMPLE ANIMALS 115

body protoplasm they are digested, the undigestible parts
being forced out through the surface of the body. Note
within the body an oval transparent spot which shows
no pulsations. This is called the nucleus and is charac-

 

Fic. 79.—Ameba sp.; showing the forms assumed by a single individual
in four successive changes. (Greatly magnified; from life.)
teristic of all cells. Make drawings showing Amceba in

three different shapes.

Ameeba produces young Amcebe by simply dividing in
halves, half of the nucleus going with each half of the rest
of the protoplasm. Each half begins at once to move about
and to feed and behave just like the parent, soon growing
to be as large as the original Amceba. In this simple
way of producing young the parent does not die at all,
116 FIRST LESSONS IN ZOOLOGY

but merely divides in two and goes on living as two new
individuals.

Amcbe continue to live and multiply by this simple
process of division as long as the conditions for living
are satisfactory. But when the stagnant pool dries up
they would be exterminated were it not for a careful pro-
vision of nature. When water begins to fail each Amceba
contracts its pseudopodia and the protoplasmic body
secretes a horny capsule about itself. It is now pro-
tected from dry weather, and can be blown by the winds
from place to place until the rains begin, when it
expands, throws off the capsule, and commences active
life again in the new puddle in which it finds itself.

Other one-celled animals.—In the same water with
Amcoebee numerous other simple one-celled animals will
certainly live. A common kind is the slipper animalcule
(Paramcecium), shown in fig. 80. This swims swiftly
about and has a body of fixed form. If specimens can-
not be readily found put some bits of hay or finely cut
dry clover in a glass dish, cover with water and leave in
the sun for several days. In this infusion slipper animal-
cules will develop by thousands. Examine a drop of it
under the microscope and observe the animalcules. Has
the body of Paramcecium an anterior and posterior end?
The short, delicate, hair-like processes on its surface are
called cilia, and are simply fine prolongations of the body
protoplasm. What is their use? At one side, beginning
near one end of the body, note a groove. What is this
for? ejected or waste particles are occasionally ejected
from the body. Where? There are two contractile
vacuoles in Paramcecium (instead of one as in Ameeba),
and there are also two nuclei instead of one. Try to find
them. In comparing Paramcecium with Ameeba it is
apparent that the body of the first is less simple than that
of the second. The definite opening for food, the two
THE AMCEBA, HYDRA, AND OTHER SIMPLE ANIMALS 117

nuclei and two contractile vacuoles, the many fixed cilia,
and the definite form of the body, which is inclosed by a
thin skin or cell-wall, are all slight advances toward a

 

 

 

 

 

Fic. 80. Fic. 81.

Fic, 80.—faramecium sp.; buccal groove at right. (Greatly magnified;
from life.)

Fic. 81.—Vorticella sp.; one individual with stalk coiled, and one with
stalk extended. (Greatly magnified; from life.)

more complex make-up. But Paramcecium is still a sin-
gle cell. Make a drawing of a Paramcecium.

Another common one-celled animal, and a curious and
interesting one, is the bell animalcule (Vorticella) (fig. 81).
The individuals of this group live together in colonies, a
single colony appearing to the naked eye as a tiny,
whitish, mould-like tuft or spot on the surface of some
118 FIRST LESSONS IN ZOOLOGY

leaf or stem or root in the water of a stagnant pool.
Touch such a spot with a needle, and if it is a bell-
animalcule colony it will contract instantly. Bring sev-
eral colonies into the schoolroom and keep in a glass of
stagnant water. Examine a colony in a drop of water
in a watch-glass or on a slide under the microscope.
Note the stemmed bell-shaped bodies which compose it.
Each bell and stem together form an individual. Tap
the slide and note the sudden contraction of the colony.
Observe the contraction of a single individual. Just what
takes place? Watch an individual expand. Examine
carefully the ‘‘bell.’’ Its upper margin is fringed with
cilia, and there is a mouth opening on the upper surface.
Find a contractile vacuole in the body, and also numer-
ous food particles which move about. The nucleus, hard
to see, is elongate and curved. The body is inclosed by
a thin cuticle. Make adrawing of a Vorticella expanded,
and of one contracted.

Both Paramcecium and Vorticella multiply by division ;
that is, by the simple dividing of the body in two, as with
Amceba. But each of these halves, or new animals, is
not exactly like its parent, and has to undergo some
change or development as well as growth (increase in
size) to become a complete Paramcecium or Vorticella.
These two kinds of one-celled animals, and most others,
also have another process of multiplication slightly more
complex than the one just described. Two individuals
sometimes come together and a part of the nucleus of
cach passes into the body and fuses with the remaining
part of the nucleus of the other. Then the individuals
move apart, and each divides in halves. This process
is called multiplication by conjugation and division. Per-
haps Amceb conjugate occasionally, but if so they do it
rarely. On the other hand Paramcecium and Vorticella
cannot go on indefinitely having generations by simple
THE AMCEBA, HYDRA, AND OTHER SIMPLE ANIMALS 119

division. An occasional generation must be produced
by the method in which conjugation precedes division.
Other kinds of one-celled animals, or Pvrotozoa, are
common in stagnant water, and under the microscope a
variety of forms may be seen swimming quickly about.
Locomotion is effected usually by many fine cilia or by
fewer, usually two, longer whiplash-like processes called

 

Fic. 82.—Sun animalcule, a fresh-water protozoan with a siliceous skele-
ton, and long thread-like protoplasmic prolongations. (Greatly magni-
fied; from life.)

flagella. Some have the soft body inclosed in a tiny shell,
as is the case with the sun animalcule shown in fig. 82.
Ocean Protozoa.—One usually thinks of the ocean as
the home of the whales and the seals and the sea-lions,
and of the countless fishes—the cod, the herring, and
the mackerel. Those who have been on the seashore

 
120 FIRST LESSONS IN ZOOLOGY

will recall the sea-urchins and starfishes and sea-anemones
which live in the tide-pools. On the beach, too, there
are innumerable shells, each representing a dead ocean
But more abundant than all of these, and i
one way more important
than all, are the myriads of
the marine Protozoa.
Although the water at
the surface of the ocean ap-
pears clear, and on super-
ficial examination seems to
contain no animals, yet in
certain parts of the world
(especially in the southern
seas) a microscopical exam-
ination of it shows it to be
swarming with
And not only is the water
\ just at the surface inhabited
by one-celled animals, but
they can be found all the
way down to a great depth.

animal.

 

Protozoa.

 

 

 

 

Fic. 83.—Stentor sp.; a protozoan

which may be fixed, like Vordice//a,
or free-swimming. at will, and
which has the nucleus in the shape
of a string or chain of bead-like
bodies. The figure shows a single
individual as it appeared when fixed,
with elongate, stalked body, and as

In a pint of ocean water
there may be millions of
these minute In
the oceans of the world the
number of them is inconceiv-

animals.

it appeared when swimming about,
with contracted body. (Greatly
magnified; from life. )

able. And it is necessary
that these Protozoa exist in
such great numbers, for they and the marine one-celled
plants (Protophyta), supply directly or indirectly the food
of all the other animals of the ocean.

Among these ocean Protozoa there are numerous kinds
with the body inclosed in a minute shell (fig. 84). These

tiny shells present a great variety of shape and _ pattern,
THE AMCEBA, HYDRA, AND OTHER SIMPLE ANIMALS 121

many being of the most exquisite symmetry and beauty.
They are perforated by many small holes through which
project long, delicate, protoplasmic pseudopodia. These
fine pseudopodia often interlace and fuse when they touch
each other, thus forming a sort of protoplasmic network
outside of the shell. In some cases there is a complete
layer of protoplasm—part of the body protoplasm of the
Protozoan—surrounding the cell externally.

/

           
    
 

  

 

inw
ow

\

Fic, 84.—Rosalina varians, a marine protozoan (Foraminifera) with cal-
careous shell. (Greatly magnified; after Schultze.)

When these tiny animals die their hard shells sink to
the bottom of the ocean, and accumulate slowly, in incon-
ceivable numbers, until they form a thick bed on its floor.
Large areas of the bottom of the Atlantic Ocean are cov-
ered with these beds. Nor is it only in present times
that such beds have been formed by the marine Protozoa.
All over the world there are thick rock strata composed
almost exclusively of the fossil shells of these simple
animals. The chalk-beds and cliffs of England and of
France, Greece, Spain, and America, were made. by
marine Protozoa. Where now is land were once oceans,

\ ~
\
122 FIRST LESSONS IN ZOOLOGY

the bottoms of which have been gradually lifted above the
water's surface. Similarly the rock called Tripoli, found
in Sicily, and the Barbados earth from the island of Bar-
bados, are composed of the shells of ancient Protozoa.
Hydra.—One of the most interesting of the simple
animals found in fresh-water ponds is Hydra (fig. 85).
Though very small com-
pared with most animals we
know, it is much larger than
any of the Protozoa, being
when expanded nearly one-
fourth of an inch long.
It is also not composed of
a single cell but of hundreds
of cells. It is one of the
simplest of the many-celled
animals, i.e., Metazoa. Hy-
dra may be found attached
to bits of sticks, stones,
and leaves in pools not too
stagnant. There are two
common kinds, one brown
and one green. Specimens
should be brought into the
schoolroom alive, and kept
Fic, 85.—Hydra; note two tentacles jn qa dish of water in the
catching an insect larva; note the |
budding young Hydra, (Natural light. To observe the
size, one-sixth inch; from life.) habits of Hydra, examine a

live specimen, attached to a bit of leaf or stick, in a

 

watch-glass, under the low power of a compound micro-
scope, or with a good magnifier.

Note the cylindrical body, attached at its base, and
with a series of tentacles projecting from its free end.
I1ow many tentacles are there? They arise in a circle
about the mouth. Have some small water-fleas in the
THE AMCEBA, HYDRA, AND OTHER SIMPLE ANIMALS 123

water and observe Hydra’s method of catching and eating
food. Note that when it captures one of the water-fleas
with its tentacles the flea soon ceases to struggle. It is
paralyzed. On the tentacles are many extremely fine,
little, stinging threads, which lie coiled up in small pockets
until prey is captured, when they uncoil, shoot out, and
sting. If Hydra catches an animal too large to be
crowded into its mouth it releases it.

Note that Hydra can contract its tentacles and its whole
body until it looks like a small egg with a rosette of short
blunt fingers at one end (fig. 85). Sometimes Hydra
may be seen with another much smaller one growing out
from it. This is a new one, forming by the process of
‘“‘budding.’’ It will grow and develop until about as
large as the parent, when it will break off, and attaching
itself elsewhere will begin an independent existence.
Hydra has the interesting power of being able to regen-
erate itself if cut in two. In such a case each half will
usually develop into a new complete Hydra.

Hydra belongs to the branch of animals called Calen-
terata, which includes also the sea-anemones, corals, and
jellyfishes (see next chapter).

For detailed accounts of the structure and life-history
of Amceba, Paramcecium, Vorticella, other Protozoa, and
Hydra, see Parker’s ‘‘ Lessons in Elementary Biology.”
CHAPTER X

OCEAN ANIMALS: SPONGES, SEA-ANEMONES,
JELLYFISHES, CORALS, STARFISHES, OYS-
TERS, CLAMS, AND SEA-SHELLS

As but few schools are situated near the seashore not
many pupils using this book will be able to see for them-
selves the interesting animals which live in the tide-pools
and on the rocks and sand floor of the coast. That a host
of curious creatures inhabit the sea is of course familiar
knowledge. The whales, dolphins, and porpoises, and
the thousands of kinds of fishes from the great sharks to
the tiny gobies and swarming herrings, are the marine
representatives of the vertebrates; the invertebrates are
represented by the plant-like sponges and sea-anemones,
the colored corals, whose skeletons form great reefs and
islands, the translucent, delicately tinted jellyfishes that
swim gracefully through the water by opening and closing
their umbrella-like bodies, the crawling starfishes, the
spiny sea-urchins, and by the host of snail-like animals
that we commonly know by their houses, the various sea-
shells which are washed up on the beach. Some of these
ocean invertebrates live far out on the open sea, like the
jellyfishes, which swarm in tropical waters; some live on
the bottom, and even at great depths, like the sponges,
but the more familiar ones, such as the sea-anemones,
starfishes, and sea-urchins live in the tide-pools along the
shore. Pupils who cannot observe the ocean animals

124
OCEAN ANIMALS ; SPONGES, SEA-ANEMONES, ETC. 125

alive should, if possible, examine some preserved speci-
mens in connection with the following briefaccount. The
hard parts of the sponges, sea-urchins, starfishes, and
corals, and various sea-shells, are common curiosities, and
may be found in somebody’s house in almost every town.

Sponges.—A bath or slate sponge is simply the skel-
eton, or part of it, of a sponge animal. In life all of this
skeleton is inclosed or covered by a soft, tough mass of
sponge flesh. Sponges are fixed, except when very
young, when they swim freely about. They are found at
all depths and in all seas, growing especially abundantly

 

Fic. 86,—A simple sponge, Grantia,; at right a longitudinal section to
show the simple body-cavity, (One-half natural size; after Jordan and
Kellogg.)

in the Atlantic Ocean and the Mediterranean. A very

few kinds live in fresh water, being found in lakes, rivers,

and canals, in all parts of the world. The shape of the
simplest sponges is that of a small vase, or nearly cylindri-

cal cup, attached at its base, and having at the free end a

large opening (fig. 86). But most sponges are very unsym-

metrical and grow more like a low, compact, bushy plant
than like the animals we are familiar with. The smallest
sponges are only I mm. (1/25 in.) high, while the largest
126 FIRST LESSONS IN ZOOLOGY

may be over a meter (39 in.) in height. In color they
may be red, purple, orange, gray, and sometimes blue.

examine a bath sponge and note the holes in it.
These are to let in and out the
sea-water, in which float the
minute bits of animal or plant
substance on which the sponge
feeds. This water also brings
oxygen for the breathing of
the sponge, and carries away
the carbon dioxide given off
by it. But the sponge has no
special organs, its soft flesh
being: able to digest food and
take up oxygen without stom-
ach or lungs.

The living sponges are col-
lected by divers, or are dragged
up by men in boats with long-
poled hooks or dredges.

They are first killed by ex-
posure to the air, and then
thrown into tanks of water.
Here the flesh decays away,
leaving the tough, horny, or
leathery skeleton, which,

 

Fic, 87.—The skeleton of a
‘class’ sponge (skeleton com. When cleaned, bleached, and
posed of siliceous spicules) from
Japan, (Natural size; from
specimen, ) Some sponges have a lime and

trimmed, is ready for market.

some a glass skeleton instead of a horny one, and the
glass skelctons are often very beautiful (see fig. 87). All
the sponges compose the animal branch called Pordfera.

Sea-anemones and corals.—The sea-anemones which
are common in tide-pools, and the coral animals which
live in tropic and sub-tropic oceans, have the same type
OCEAN ANIMALS: SPONGES, SEA-ANEMONES, ETC. 127

of body as that shown by Hydra (described in Chapter
IX), but are much larger. When the tide is out, ex-
posing the dripping seaweed-covered rocks, and the little

 

 

 

Fic. 88.—Sea-anemones, Bunodes californica, open and closed individuals,
one-half natural size. The closed individuals in upper right-hand
corner show the external covering of small bits of rock and _ shell,
characteristic of most individuals of this species. (From living speci-
mens in a tide-pool on the Bay of Monterey, California.)

basins are left filled with clear sea-water, the brown and

green and purple ‘‘sea-flowers ’’ may be seen fixed to the

rocks by the base, with the mouth opening and circlet of

slowly moving tentacles hungrily ready for food (figs. 88
128 FIRST LESSONS IN ZOOLOGY

and 89). Touch the fringe of tentacles with your finger-tip
and feel how they cling to it. If it were a small animal,
like a sea-snail, these deadly tentacles would hold it fast
and slowly carry it into the mouth. Inside the body is a
cylindrical hollow, which is really a primitive kind of
stomach. But there is no heart nor brain nor lungs in

 

Fic. 89.—Sea-anemones in a tide-pool at Point Lobos, near Monterey, Cal. ;
these specimens are six inches in diameter across the mouth end.
(Photograph by author, from living specimens 77 s7¢v.)

this simple body. It is only a thick-walled sac, with the

mouth surrounded by food-catching tentacles.

The coral animals, or coral polyps, are simply a kind
of sea-anemone which secretes in its otherwise soft body-
wall a stony skeleton of carbonate of lime which persists
after the polyp is dead. We know these animals chiefly
by their skeletons, which we see in masses in collections,
OCEAN ANIMALS: SPONGES, SEA-ANEMONES, ETC. 129

or made into ornaments. But in tropical oceans there
are whole islands of coral (figs. 90, 91), or long coral reefs

 

 

 

 

 

Fic. 90.—Coral islands, Nukulai and Mokaluwa, of the Fiji group. (After
photograph by W. C. McWoodworth.)

(fig. 92) fringing the shores of continents, formed by the
skeletons of millions of polyps. For as they live closely

 

   

Soe
a

a

 

Fic. 91.—Western part of Storm Island (Fijis), a coral island; the trees are
cocoanut palms. (After photograph by W. C. McWoodworth.)

massed together in great colonies their skeletons form solid
stony banks. Coral islands have a great variety of form,
130 FIRST LESSONS IN ZOOLOGY

but the elongated, circular, ring-shaped, and crescent
forms predominate. In the Atlantic Ocean they are
found along the coasts of Southern Florida, Brazil, and
the West Indies; in the Pacific and Indian oceans there

 

 

 

 

 

Fic. 92.—View of a coral reef off the coast of Brazil (near Bahia); photo-
graph taken at low tide with the coral projecting just above the surface
(Photograph by J. C. Brauner.)

are great coral reefs on the coasts of Australia, Madagas-

car, and elsewhere; and certain large groups of inhabited

islands, as the Fiji, Society, and Friendly Islands are
almost exclusively of coral formation.

There are over 2000 kinds of coral polyps known, and
their skeletons vary much in appearance (fig. 93). Be-
cause of the suggestive appearance of some of these they
have received common names, as the organ-pipe coral,
brain coral, etc. The red coral of which jewelry is made
grows chiefly in the Mediterranean Sea. It is gathered
OCEAN ANIMALS: SPONGES, SEA-ANEMONES, ETC. 131

specially on the western coast of Italy, and on the coasts
of Sicily and Sardinia. Most of this coral is sent to
Naples, where it is cut into ornaments.

Jellyfishes.—By walking along the sea-beach soon
after a storm one may find many shapeless masses of a

 

Fic. 93.—Skeleton of a branching coral, Madrepora cervicornis. (From
specimen.)

clear jelly-like substance scattered here and there on the
sand. These are the bodies or parts of bodies of jelly-
fishes which have been cast up by the waves. Exposed
to the sun and wind they soon die or evaporate away to
a small shrivelled mass. The flesh ofa jellyfish contains
hardly more than one per cent of solid matter, all the rest
of it being water.

Jellyfishes, although closely related to the fixed polyps,
132 FIRST LESSONS IN ZOOLOGY

some indeed being the immediate offspring of them, have
a body of quite different appearance. It corresponds in
general to an umbrella or bell (fig. 94), around the edge
of which are disposed numerous threads or tentacles
(corresponding to the tentacles of the polyp). The

 

 

 

 

Fic. 94.—A jellyfish or medusa, Gonfonema vertens, eating two small fishes.
(Natural size; from specimen from Atlantic Coast.)

mouth-opening is at the end ofa longer or shorter pro-
jection which hangs from the middle of the under side of
the umbrella, like a short, thick handle. The body cavity,
or primitive stomach, extends out into the umbrella-
shaped part of the body. By alternately clapping shut
and opening the umbrella the jellyfish swims about.
Jellyfishes occur in great numbers on the surface of the
ocean, and are familiar to sailors under the name of
‘«sea-blubs.’’ Some live in the deeper waters; a few
OCEAN ANIMALS : SPONGES, SEA-ANEMONES, ETC. 133

specimens have been dredged up from depths of a mile
below the surface. They range in size from ‘‘ umbrellas ”’
or disks a few millimeters in diameter to disks of a diam-
eter of two meters (24 yards). They are all carnivorous,
preying on other small ocean animals, which they catch by
means of their tentacles, provided with stinging-threads.
The tentacles of some of the largest jellyfishes ‘‘ reach
the astonishing length of 40 meters, or about 130 feet.’’
Many of the jellyfishes are beautifully colored, although
all are nearly transparent. Almost all of them are phos-
phorescent, and when irritated some emit a very strong
light.

The so-called ‘colonial jellyfishes’’ are floating or
swimming colonies of jellyfishes and polyps composed of
many individuals closely joined. These individuals are
all of one species, but are of different forms or kinds,
each kind having a special function to perform in the life
of the colony. For example, some individuals catch all
the food for the colony; some make the motions; some
are especially sensitive to the presence of enemies or prey,
and some produce all the young. These various individ-
uals act like the separate organs of our own body. The
beautiful Portuguese ‘‘man-of-war’’ (fig. 95) is one of
these colonial jellyfishes. It appears as a delicate bladder-
like float, brilliant blue or orange in color, usually about six
inches long, and bearing on its upper surface, which pro-
jects above the water, a raised parti-colored crest, and on
its under surface a tangle of various appendages, thread-
like, with grape-like clusters of little bell- or pear-shaped
bodies. Each of these parts is a specially modified indi-
vidual, produced by budding from an original central
polyp. The Portuguese man-of-war is very common in
tropical oceans, and sometimes vast numbers swimming
together make the surface look like a splendid flower-
garden.
FIRST LESSONS IN ZOOLOGY

 

   

Pic. 95.— The Portuguese man-of-war (2Avsalia radi

sp.) (One-half natural size:
from Athintic Coast. )

from specimen

 

The sea-anemones,
corals, and jellyfishes
compose the animal
branch Celenterata.
Starfishes and sea-
urchins, — Among
the most easily found
and most readily rec-
ognized seashore in-
vertebrates are the
starfishes and_ sea-
urchins, which belong
to the animal branch
called Echinodermata
(fig. 96). Although
these animals do not
look at all alike, the
starfishes having a
body composed of
central disk and long
rays or radiating arms,
and the
looking

sea-urchins
like spiny
flattened balls, they
are really closely re-
lated. In each the
body, with its various
organs, is built on a
ate plan of struc-
OCEAN ANIMALS : SPONGES, SEA-ANEMONES, ETC. 135

in the center of the under side and all the body parts
radiating out from this center.
If a starfish, either fresh or preserved in alcohol, can

   

Fic. 96.—A group of Echino-
derms; the upper one a star- -
fish, Asterina mineata, the
one at the right a starfish,
Asterias ocracia, at the left
a brittlestar, species un-

known, and at bottom two sea-urchins, Strongylocentrotus franciscanus.

(One-third natural size; from living specimens in a tide-pool on the Bay

of Monterey, California.)

be had for examination, note that the body is covered by
a skeleton composed of little plates, on which are short
stout spines arranged in irregular rows. At the tip of
each arm or ray there is a small red speck, the very
simple eye of the animal. The starfish cannot see with
this ‘‘eye’’; it can only distinguish between light
136 FIRST LESSONS IN ZOOLOGY

and darkness. On the under side the mouth is in
the center, and from it along each ray runs a groove.
In each groove may be seen two double rows of soft,
tubular processes with sucker-like tips called the tube-
feet. These are the organs of locomotion. If live star-

 

Fic. 97.—Starfishes of various kinds in a tide-pool on the Bay of Monterey,
California; note two with five rays, three pentagonal, and two with
many rays; also see large sea-urchins. (Photograph by author, from
living specimens ve sé/z.)

fishes can be watched the slow locomotion by means
of the tube-feet may be seen, and perhaps also the
peculiar mode of taking food. Starfishes are carnivo-
rous, feeding on crabs, snails, and the like. If the live
prey is too large to be taken into the mouth it is sur-
rounded by the stomach, which is pushed outward for
this purpose. Jt secretes fluids which kill the prey, after
which the soft parts are digested.
OCEAN ANIMALS: SPONGES, SEA-ANEMONES, ETC. 137

Starfishes hatch from eggs, and in their early stages
are very different in appearance from the adults, being
more or less ellipsoidal in shape, and having many cilia
on the outer surface. They swim freely about in the sea,
feeding on microscopic organisms. In size starfishes vary
from a fraction of an inch in diameter to three feet. They
are yellow or red, or brown or purple, and the number of
rays varies from five to thirty or more in different kinds
(fig. 97). Some have the spaces between the rays filled
out nearly to the tips of the arms, making the animal

 

Fic. 98.—A sea-urchin, Strongylocentrotus franciscanus. (One-half natural
size; from specimen from Bay of Monterey, Calif.)

simply a pentagonal disk. Starfishes are able to re-
generate a lost ray—that is, if one or more rays are bitten
off by enemies, new ones grow out in their places. I
once found a starfish in Samoa which was regenerating
four new rays and the central disk from a single old ray!

The sea-urchins (fig. 98), of which more than three hun-
dred species are known, while without arms or rays yet show
their radiate structure in having the tube-feet arranged in
five rows radiating from the center. This canbe seenina
‘«shell’’ or body-wall, from which the spines have been
138 FIRST LESSONS IN ZOOLOGY

removed (fig. 99). Around the mouth, which is at the cen-
ter of the under side, are five strong teeth. Like the star-
fishes, the young sea-urchins are free swimming creatures
of very different appearance from the adults. Their food
consists of small marine animals and of bits of organic
matter which they collect from the sand and deébris of the
ocean floor. Many of the sea-urchins are gregarious,
living togther in great numbers. Some have the habit
of boring into the rocks of the shore between tide-lines.
I have seen thousands of small, beautifully colored purple
sea-urchins lying each in a spherical pit or hole in hard
conglomerate rock on the California coast. How they

 

Fic. 99.—‘ Test” of sea-urchin, S/rongylocentrolus franciscanus, with
spines removed. (From specimen. )

are enabled to bore these holes is not yet known. There
is great variety in size and color among these animals.
The colors are brown, olive, purple red, greenish blue,
etc.

A few kinds of sea-urchins have a flexible shell or
test. The Challenger expedition dredged up from the
sea bottom some sea-urchins, and when placed on the
ship’s deck ‘‘the test moved and shrank from touch when
handled, and felt like a starfish.’’ The cake-urchins or
sand-dollars are sea-urchins having a very flat body with
OCEAN ANIMALS: SPONGES, SEA-ANEMONES, ETC. 139

short spines. They lie buried in the sand, and are often
very brightly colored.

Their hard bleached tests with the spines all rubbed off
are common on the sands of both the Atlantic and
Pacific coasts.

Oysters, clams, and sea-shells.— Very different from
the sea-anemones, jellyfishes and starfishes are those
inhabitants of the ocean commonly called ‘‘shell-fish.’’
These include the oysters, clams, pectens, shipworms,
and the host of snail-like creatures whose lime ‘‘ houses ’”’
of manifold shapes and colors we know under the ex-

 

FIG. 100. Fic. 101.

Fic. 100..—The eastern oyster, Ostrea virginiana, (One-third natural size;
after photograph by W. H. C. Pynchon.)
Fic, 101.—Young oyster. (Greatly magnified; after Brooks.)

pressive name of sea-shells. All these animals which
with the fresh-water mussels and the pond and land
snails and slugs make up the branch of J/ollusca, have a
soft, sac-like body, not built on the radiate plan like the
starfishes nor on the segmented plan like the insects, but
on the plan well shown by the snail. The body is pro-
tected by a firm shell of carbonate of lime, which may
be in two pieces, bivalved, as in the oyster and clams, or
in one piece, univalved, as in the usual spiral sea-shell
type.

The oyster (fig. 100) is carefully cultivated by man in
many countries. It has two shells, or two dissimilar
140 FIRST LESSONS IN ZOOLOGY

shell halves, one valve being hollowed out to receive the
body, while the other is nearly flat. It is attached to the
sea bottom by the outside of the hollowed-out valve.
When first hatched the young oyster (fig. IOI ) swims
freely about by means of its cilia; after a few days it
attaches itself to some solid object and grows truly oyster-
like. Much care has to be taken in cultivating oysters
to furnish proper conditions for growth and develop-
ment. The young oysters when first attached are called
‘*spat’’; when a little older this ‘‘spat,’’ now called

 

My Hall ie AAS

Fic. 102.—/%olas sp., a mollusc, burrowing in sandstone. (Photograph by
C. IL. Snow; permission of Amer. Soc. Civil Engineers. )
‘“«seed,’’ may be transplanted to new beds, which are
stocked in this way. In fact some beds have constantly
to be thus restocked, the young oysters produced on them
not finding good places to attach themselves, and so
swimming away. Sometimes picces of slate, pottery,
etc., are strewed about the oyster-beds to serve as ‘‘col-
lectors’’—that is, as places for the attachment of the
young oysters. The extent of the acreage of the Ameri-
can oyster-beds is larger than that of any other country.
The Baltimore oyster-beds on the Chesapeake River and
its tributaries cover 3000 acres, and produce an annual

crop of 25,000,000 bushels.
OCEAN ANIMALS: SPONGES, SEA-ANEMONES, ETC. 141

The edible clams are of several different species. The
hard-shell clam or ‘‘quohog’’ as it is often called, is

 

Fic. 103.—The giant yellow slug of California, Ariolimax californica.
This slug reaches a length when outstretched of twelve inches.
(From living specimen. )

found along the Atlantic coast from Texas to Cape Cod.

It is common on sandy shores, living chiefly on the

sandy and muddy plots just beyond low-water mark. It

 

 

Fic. 104.—Three Pacific Coast nudibranchs or sea slugs; Doris tuberculata
(in lower left-hand corner), Echinodoris sp. (upper one), and Triopha
modesta (at right). (Natural size; from living specimens in a tide-
pool on the Bay of Monterey, California.)

also inhabits estuaries, where it most abounds. It burrows

a short distance below the surface, but is frequently

found crawling at the surface with the shell partly ex-

posed. The soft-shell clam, ‘‘ the clam par excellence,

which figures so largely in the celebrated New England
142 FIRST LESSONS IN ZOOLOGY

clambake, is found in all the northern seas of the world.

All along the coasts of the eastern States every
sandy shore, every mud flat, is full of them, and from
every village and hamlet the clam-digger goes forth at
low tide to dig these esculent bivalves. The clams live
in deep burrows in the firm mud or sand, the shells some-
times being a foot or fifteen inches below the surface.

 

 

Fic. 105.—A group of marine Pacific Coast molluscs; in upper left-hand
corner, Purpura saxicola; next to the right, Zittorina scutulata; farthest
to right. limpets, -lemara spectrum; left-hand lower corner, Afviilus
californianus; in right-hand lower corner the black shells just above
the large clam-shell, Chlorostomum funebrale. (Natural size; from
living specimens in a tide-pool on the Bay of Monterey, California.)

When the flats are covered with water his clamship ex-
tends his long siphon up through the burrow to the surface
of the sand, and through one of these tubes the water
and its myriads of animalcules is drawn down into the
shell, furnishing the gills with oxygen and the mouth
with food, and then the water charged with carbonic
acid and refuse is forced out of the other siphon. When
the tide cbbs the siphons are closed and partly with-
drawn.”’
OCEAN ANIMALS: SPONGES, SEA-ANEMONES, ETC. 143

Among the univalved ocean molluscs there is a great
variety in the size and shape and coloring of the shells.
Many are beautifully colored and patterned; others are
oddly and fantastically shaped. The cowries, or porce-
lain shells, familiar in collections of ocean curiosities,
have a large body whorl and a very short flat spire, and
the brightly colored shell looks as if enamelled. Some
of the coast tribes of Africa once used, and perhaps still

 

 

 

 

Fic, 106,—The giant squid, Ommatostrephes californica, (From specimen
with body (exclusive of tentacles) four feet long, thrown by waves on
shore of the Bay of Monterey, California.)

use, to some extent, cowries as money. The limpets

are among the most abundant of the seashore molluscs,

their low, broadly conical shells being plentifully scattered
over the rocks between tide-lines (fig. 105). The oyster-
drills are molluscs with odd spiny shells, which do much
harm by settling down on the. oysters, boring holes
through the shells, and eating the soft parts within.

The helmet-shells, from which shell cameos are cut, are

composed of layers of shell material of different colors.

Among the specially beautiful shells are the cone-shells,

the olive-shells, the ivory-shells, etc.
CHAPTER XI.

WORMS, CRAYFISH, CENTIPEDS, AND OTHER
SMALL LAND ANIMALS.

Earthworms and leeches.—Bring into the schoolroom
large live earthworms. They may be found in the day-
time by digging, or at night by searching with a lantern.
They often come above ground in the daytime after a
heavy rain. They may be kept in flower-pots filled with
damp soil, and should be fed bits of raw meat, preferably
fat, bits of onion, celery, cabbage, etc.

Examine a live specimen put ona piece of moist paper.
Note that the body is made up of rings or segments.
Are there any legs? How does the earthworm move
along? Can you find some short fine bristles, called
seta, on the body? The broad thickened ring or girdle,
including several segments near the head, is called the
clitellum. It secretes the cases in which the eggs are
laid. Make a drawing of the worm, showing all the
external features you can make out.

tarthworms live in soft moist soil which is rich in
organic matter. Their food is taken into the mouth
mixed with dirt and sand. As this mixture passes
through the long alimentary canal the organic particles
are taken up and digested. The eggs are laid in a horny
capsule which lies in the earth until the young worms
emerge. Only a part of the eggs develop in each cap-
sule, the rest being eaten by the growing young. Earth-

144
WORMS, CRAYFISH, CENTIPEDS, ETC. 145

worms of various kinds are found in all parts of the world
except in desert or arid regions. In size these different
kinds vary from 1 mm. (, in.) to 2 meters (24 yards)
in length.

Leeches (fig. 107) are familiar to boys who go in swim-
ming. Some live specimens should be brought into the
schoolroom. The body of a leech is flattened instead of
being cylindrical as in the earthworm, and tapers at both

 

Fic, 107, A leech, Clepsine, ventral view; posterior sucker at left.
(Natural size; after photograph by E. R. Downing, in Davenport’s
Zoology.)

ends. In the live animal it can be greatly elongated
and narrowed, or much shortened and broadened. It is
composed of many segments (not as many as there are
cross lines, however, each segment being transversely
annulated), and bears at each end on the ventral surface
a sucker, the posterior one being the larger. These
suckers enable the leech to cling firmly to other animals.
The mouth is at the front end of the body on the ven-
tral surface and is provided with sharp jaws. Leeches
live mostly on the blood of other animals. The common
leech fastens itself upon its victim by means of its suck-
ers, then cuts the skin, fastens its oral sucker over the
wound, and pumps away until it has completely gorged
itself with blood, distending enormously its elastic body,
when it loosens its hold and drops off. Its biting and
146 FIRST LESSONS IN ZOOLOGY

sucking cause very little pain, and in olden days physi-
cians used the leeches when they wanted to ‘‘bleed’’
a person. A common European species much used
for this purpose is known as the ‘‘ medicinal leech.’’
Most of the leeches lay their eggs in small packets or
cocoons. These cocoons are dropped in soil on the
banks of a pond or stream so that the young may have a
moist but not too wet environment. The young issue
from the eggs in four or five weeks, but they grow very
slowly and it is several years before they attain their full
‘size. Leeches are long-lived animals, some being said
to live for twenty years.

Vinegar-eels, hairworms, and trichine.—The group
of roundworms, so called from their slender, smooth,
cylindrical bodies, contains some interesting animals.
Familiar examples are the vinegar-eels (fig. 108) which
can be found in mouldy vinegar, and the hairworms or
horse-hair snakes which are often seen in fresh-water
pools after a rain. Some people believe these worms to
be horsehairs which have turned into animals, and others
believe that they come down with the rain. They have
in reality come from the bodies of insects in which they
pass their young or larval stages as parasites. The hair-
worms all live as parasites during their larval stages, and
as free independent animals in the adult. A parasite is
an animal which lives for part or all of its life in or on
the body of another animal called the host, and which
feeds on the blood or other tissues of this host. Some ot
the hairworms require two distinct hosts for the com-
pletion of their larval life, living for a while in the body
of one, and later in the body of another. The first host
is usually a kind of insect which is eaten by the second.
The eggs are deposited by the free adult female in
slender strings twisted around the stems of water-plants.
The young hairworm on hatching sinks to the bottom of
WORMS, CRAYFISH, CENTIPEDS, ETC. 147

the pond, where it moves about hunting for a host in
which to take up its abode.

The terrible 772chzna spiralis, which produces the dis-
ease called trichinosis, is another roundworm of which
much is heard. This very small worm lives in its adult
condition in the intestine of man as well as in the pig

 

Fic. 108. FIG. 109.

Fic, 108.—-A vinegar eel, Anguil/ula sp. (Much enlarged; from a living
specimen. )

Fic, 109.—7richina spiralis, encysted in muscle of a pig. (Greatly magni-
fied; from specimen. )

and other mammals. The young, which are born alive,
burrow through the walls of the intestine, and are either
carried by the blood, or force their way, all over the body,
lodging usually in the muscles. Here they form for
themselves little cells or cysts in which they lie (fig. 109).
148 FIRST LESSONS IN ZOOLOGY

The forming of these thousands of tiny cysts injures the
muscles and causes great pain, sometimes death to the
host. Such infested muscle or flesh is said to be ‘ trichi-
nosed,’’ and the flesh of a trichinosed human subject has
been estimated to contain 100,000,000 encysted worms.
To complete the development of the encysted and sexless
Trichine the infested flesh of the host must be eaten by
another animal in which the worm can live, e.g., the flesh
of man by a pig or rat, and that of a pig by man. In

  
 
  

  
   

 

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Athen HANH

Kt

  

{

Fic, 110.—Tapeworm; head magnified, at left; whole worm may be
several yards long. (After Leuckart.)

such a case the cysts being dissolved by the digestive
juices, the worms escape, develop reproductive organs
and produce young, which then migrate into the muscles
and induce trichinosis as before. But, however badly
trichinosed a piece of pork may be, thorough cooking of
it will kill the encysted trichina, so that it may be eaten
without danger. Some people, however, are accustomed
to eat ham, which is simply smoked pork, without cook-
ing it, and in such cases there is always great danger.
WORMS, CRAYFISH, CENTIPEDS, ETC. 149

The earthworms, leeches, vinegar-eels, hairworms, and
trichinee belong to the great branch Vermes.

The crayfish.—The crayfish, or crawfish, is found in
most fresh-water ponds and streams of the United States
west of Massachusetts. Crayfishes may be taken by a
net baited with dead fish, or may be caught in a trap

 

 

 

 

Fic. 111.—A group of marine worms; at the lefta gephyrean, Dendrostomum
cronjhelmi, the upper right-hand one a nereid, Mereis sp., the lower
right-hand one, Polynoe brevisetosa. (From living specimens in a tide-
pool on the Bay of Monterey, California.)

made from a box with ends which open in, and baited
with dead fish or animal refuse of any sort. They should
be brought alive into the schoolroom and kept in a moist
chamber. Observe live specimens to see the character-
istics of locomotion, and the use of the pincers and the
mouth-parts in taking food.

Kill some specimens with chloroform and study the ex-
ternal structure. Note that the body is made up of a
series of body-rings or segments (as in the case of insects
and worms), which are distinct in the hinder part of the
body (abdomen), but are fused in the front forming the
cephalothorax. The whole body is covered with a firm,
calcareous exoskeleton, which acts as a protective cover-
ing for the soft parts within, and also as a firm place for
the attachment of the muscles.
150 FIRST LESSONS IN ZOOLOGY

The cephalothorax is covered above and on the sides by
the carapace, which is divided by a transverse line into a
front part or head and a hinder part or thorax. At the
anterior end of the head is a sharp projection, the ros-
trum. Where is the mouth? Where are the eyes ?
Remove one of the eyes and examine its outer surface
with a microscope. <A bit of the outer wall should be
torn off and mounted on a glass slide. Note that it is
made up of a great many little facets placed side by side.
Each of these is the external window of a single eye ele-
ment or ommatidium. An eye composed in this way is
called a compound eye. (See accounts of the compound
eyes of insects on pp. 22 and 112.) Make a drawing of
the surface of part of an eye. In front of the eyes note
two pairs of slender many-segmented appendages. The
shorter pair, the antennules, are two-branched. Remove
one of them and note at its base a small slit along the
upper surface. This opens into a small, bag-like structure
which contains fine sand-grains. The bag is protected by
a series of fine bristles along the edge of the slit. The
structure is believed to be an auditory or hearing organ.
The longer pair of appendages are the antenne, and in
the fine, hair-like projections upon the joints is believed
to be located the sense of smell. Beneath the basal
portion of each antenna there is a flat, plate-like projec-
tion, at the base of which on the upper edge will be noted
a small opening, the exit of the kidney, or green gland.

Stick one point of the scissors under the posterior end
of the carapace on the right side, and cut forward, thus
exposing a large cavity, the gill-chamber. Remove all
of the mouth-parts, legs, and abdominal appendages from
the right side, being careful to leave the fringe-like parts,
the gills, attached to their respective legs. Place all of
the appendages in order on a piece of cardboard.

Examine the abdominal appendages, called pleopods,
WORMS, CRAYFISH, CENTIPEDS, ETC. 151

 
  
 

antennule

ode _--uropod

Fic, 112.—Ventral aspect of crayfish (Camdarus sp.), with the appendages
of one side disarticulated.

 
  
152 FIRST LESSONS IN ZOOLOGY

or swimming feet. Has each abdominal segment a pair
of these? Each is composed of a basal part, the proto-
podite, and two terminal parts, an inner one, endopodite,
and an outer one, exopodite. In the males the first and
second pleopods are larger than the others. In the
females the pleopods serve to carry the eggs, and the
first two pairs are very small or absent. The last pair of
abdominal appendages are called uropods, and together
with the last segment, called the telson, form a broad,
flap-like tail. Is there any correspondence between the
uropods and pleopods ?

Examine the appendages of the cephalothorax. They
may be divided into three groups, an anterior group of
three pairs of mouth-parts (belonging to the head) of
which the first pair are the mandibles and the others the
maxilla; a second group of three pairs of foot-jaws or
maxillipeds, belonging to the thorax; and a third group
of five pairs of walking-legs. The mandibles, lying next
to the mouth-opening are hard and jaw-like, and lack the
exopodite; the second manille have a large paddle-like
structure which extends back over the gills on each side
within the space above them called the branchial cham-
ber. It is by means of this paddle-like structure (the
scaphognathite) that currents of water are kept up through
the gill-chambers. The manillipeds increase in size from
first to third pair. What pairs of walking-legs bear gills ?
These gills are the organs by which the blood is purified.
The blood of the crayfish flows into the large vessels on
the outer side of the gill, and thence into the fine vessels
in the leaf-like lamellae. It thus flows by the thin mem-
branous wall of the gill on the inside; while the water
with air dissolved in it flows by the thin membranous
wall on the outside. The oxygen of the air in the water
passes through the thin walls of the gill and blood-vessels
into the blood, while the carbon dioxide passes from the
WORMS, CRAYFISH, CENTIPEDS, ETC. 153

blood out through the thin walls into the water. Note
the pincer-like appendages of the first pair of legs.
These are the chele with which food is torn into bits
and placed in the mouth.

In meadows where water stands for certain seasons of
the year there may be noticed many scattered holes with
slight elevations of mud about them. These are mostly
the burrows of crayfish. During the dry season the ani-
mal digs down until it reaches water, or at least a damp
place, where it rests until wet weather brings it to the
surface once more. One of these burrows followed in the
process of digging a mining shaft extended vertically
down to a distance of twenty-six feet, where the crayfish
was tucked snugly away.

The eggs are carried by the female on her abdominal
appendages. Previous to laying them she rubs off, with
the fifth pair of legs, all the dirt from the appendages and
smears them with a sticky secretion. When the eggs are
laid, which is during the last of March or April in the
Central States, they are caught on the sticky pleopods,
where they remain attached in clusters. After some
weeks the young crayfishes issue from the eggs. In gen-
eral appearance they are not very unlike the adults.
They grow very rapidly at this stage. As the animal is
inclosed in a hard shell, growth can take place only
during the period just following the moult, for the
crayfish casts its hard shell periodically, and it is
while the new shell is forming that it does its growing.
When it moults it casts not only the exoskeleton,
but also the lining of part of the alimentary canal.
After the females have hatched their young many of
them die in the shallow pools, in which places the
dried-up skeletons are noticeable during the summer
months.

For an exhaustive account of the biology of the cray-
154 FIRST LESSONS IN ZOOLOGY

fish, see Huxley’s ‘*The Crayfish: An Introduction to
Zoology.’

Lobsters and crabs.—Lobsters and crabs are not land
animals, as they live only in the ocean, but they belong
to the same class as the crayfish, and are therefore briefly
discussed here. The crayfishes, lobsters, crabs, pill-bugs
and water-fleas (described in the next section) all belong
to the class Crustacea of the branch Arthropoda. The
lobsters are very much like crayfish in all structural char-
acters, although much larger. They live cu the rocky
sandy ocean-bottom at shallow depths. Thev are caught
in great numbers in so-called ‘‘ lobster-pots,’’ a kind of
wooden trap baited with refuse. The number thus taken
upon the shores of New England and Canada amounts to
between twenty and thirty million annually. Live lobsters
are brownish or greenish, with bluish mottling; they turn
red when boiled. <A single female will lay several thou-
sand eggs. They are greenish, and are carried about by
the mother until the young hatch. The young are free-
swimming larve until they reach a length of half an inch.

Most crabs (fig. 113) differ from the lobsters, crayfishes,
and shrimps in having the body short and broad, instead
of clongate. This is due to the special widening of the
carapace and the marked shortening of the abdomen.
The abdomen, moreover, is permanently bent under the
body, so that but little of it is visible from the dorsal
aspect. The numbcr of abdominal legs or appendages is
reduced. When the tide is out the rocks and tide-pools
of the ocean are alive with crabs. They ‘‘scuttle’’ about
noisily over the rocks, withdrawing into crevices or
sinking to the bottom of the pools when disturbed. They
move as readily backward or sidewise, ‘ crab-fashion,”’
as forward. They are of various colors and markings,
often so patterned as to harmonize very perfectly with the

general color and appearance of the rocks and sea-weeds
WORMS, CRAYFISH, CENTIPEDS, ETC. 155

among which they live. The spider-crabs are especially
strange-looking creatures, with unusually long and slender

 

Fic, 113.—Some crabs and barnacles of the Pacific coast; the short sessile
acorn barnacles in the upper left-hand corner belong to the genus
Balanus; the stalked barnacles in the upper right-hand corner are or
the species Pollicipes polymenus; the largest crab (upper left-hand) is
Brachynotus nudus; the one in the left-hand lower corner is a young
rock.crab, Cancer productus; the crab in the seaweed at the right is a
kelp-crab, Zpialtus productus, while the two in snail-shells in lower
corner are hermit-crabs, Pagurus samuelis. (About one-half natural
size; from living specimens in a tide-pool on the Bay of Monterey,
California. )

legs and a comparatively small body-trunk. They include
the Macrocheira of Japan, the largest of the crustaceans.
Specimens of this crab are known measuring twelve to six-
156 FIRST LESSONS IN ZOOLOGY

teen feet from tip to tip of extended legs; the carapace is
only as many inches in width or length. The soft-shelled
crab is a species common along our Atlantic coast. It is
‘«soft-shelled ’’ only at the time of moulting, and has to
be caught in the few days intervening between the shed-
ding of the old hard shell and the hardening of the new
body-wall. The little oyster-crabs (Pinnotheres) which
live with the live oyster in the cavity inclosed by the
oyster-shell are well-known and interesting creatures.
They are not parasites preying on the body of the oyster,
but are simply messmates feeding on particles of food
brought into the shell by the currents of water created by
the oysters. ,

Among the most interesting members of this family are
the hermit-crabs (fig.113), familiar to all who know the sea-
shore. There are numerous species of these, all of which
have the habit of carrying about with them, as a protective
covering into which to withdraw, the spiral shell of some
gastropod mollusc. The abdomen of the crab remains
always in the cavity of the shell; the head, thorax, and
legs projecting from the opening, to be withdrawn into it
when the animal is alarmed or at rest. The abdomen
being always in the shell, and thus protected, loses the
hard body-wall, and is soft, often curiously shaped and
twisted to correspond to the spiral cavity of the shell. It
has on it no legs or appendages except a pair for the hind-
most segment, which are modified into hooks for holding
fast to the interior of the shell. As the hermit-crab grows
it takes up its abode in larger and larger shells, some-
times killing and removing piecemeal the original inhab-
itant. Certain hermit-crabs spend much of their time on
land, traveling far inland, and making burrows in the
ground. These ‘‘ land-crabs '’ are common in the South
Pacific islands. Some hermit-crabs always have attached
to the shell certain kinds of sea-anemanes, It is believed
WORMS, CRAYFISH, CENTIPEDS, ETC. 157

that both crab and sea-anemones derive advantage from
this arrangement. The sea-anemone, which otherwise
cannot move, is carried from place to place by the crab,
and so may get a larger supply of food, while the crab is
protected from its enemies, the predaceous fishes, by the
stinging-threads of the sea-anemone, and also perhaps by
the concealment of the shell its presence affords. This
living together by two kinds of animals to their mutual
advantage is called commensalism or symbiosis.
Pill-bugs and water-fleas.—Pill-bugs, wood-lice, or
damp-bugs (fig. 114), as they are venpiely called, ey be
readily found in concealed moist i~ og
places, under stones or boards, on
damp soil, etc. They run about
quickly, and feed chiefly on decay-
ing vegetable matter. They are
night-scavengers. Although com-
monly called ‘‘ bugs ’’ and supposed
to be insects, they really belong
to the crustaceans, that class of ani-
mals which includes the crayfish,
lobster, and crab. Examine the

 

Fic. 114.—A damp-bug,
i ; Isopod, species not de-
body of a dead pill-bug. It is oval termined. (Four times

: natural size; from speci-
and convex above, rather purplish or Se ; from sp

grayish brown, and smooth. Note its division into head,
thorax, and abdomen. Find the eyes, the antenna, and
the mouth-parts. All the locomotory appendages are
adapted for walking or running, not swimming. How
many pairs of legs are there? Find gills and gill-covers.
Although pill-bugs do not live in the water they breathe
partly at least by means of gills (though they may breathe
partly through the skin). It is therefore necessary for
them to live in a damp atmosphere, so that the gill mem-
branes may be kept damp. If these are not moist, they
will not permit the exchange of gases.
158 FIRST LESSONS IN ZOOLOGY

The water-fleas (Cyclops) (fig. 116) are among the
smallest of the crustaceans. They are common in
ponds and slow streams; and some should be kept in
glasses of water in the schoolroom. Though only about
I mm. (1/25 in.) long, they are readily seen with the
unaided eye. They are white, rather elongate, and have

 

Fic. 115.—A_ water-flea, Crelops sp. Female with egg-masses. (Much
enlarged; from living specimen.)

a rapid, jerky movement. Itxamine live specimens in a

watch-glass. Note the ‘‘split-pear’’ shape, the body

being broadest near the front, tapering posteriorly, flat

beneath, and convex above. Note the forked processes

at the tip of the abdomen, also the two pairs of antenna,
WORMS, CRAYFISH, CENTIPEDS, ETC. 159

the single median eye, the mouth-parts, and five pairs of
legs (the last pair very small). There are no gills. Some
of the specimens, females, may have attached to the first
abdominal segment on either side an egg sac. Watch
the Cyclops capturing and feeding Paramcecium and
other microscopic animals. Make a drawing of Cyclops,
showing its parts.

Water-fleas are extremely abundant, having great
power of multiplication. ‘* An old Cyclops may produce
forty or fifty eggs at once, and may give birth to eight or
ten broods of children, living five or six months. As the
young begin to reproduce at an early age, the rate of
multiplication is astonishing. The descendants of one
Cyclops may number in one year nearly 4,500,000,000,
or more than three times the total population of the earth,
provided that all the young reach maturity and produce
the full number of offspring.” The Cyclops feed on
smaller aquatic animals, such as Protozoa, Rotifera, etc.
They in turn serve as food for fishes; and because of their
immense numbers and occurrence in all except the swift-
est fresh waters they form the main food of most of our
fresh-water fishes while young. Many aquatic insect
larve feed almost exclusively on them.

Thousand-legged worms and _ centipeds.— Under
stones and logs, or buried in the soil, will be found at
almost any time of the year, in almost any part of the
country, specimens of thousand-legged worms. There
are two general types of animals belonging to this group,
the true thousand-legged worms, of which a common
representative is the large, blackish, cylindrical galley-
worm (fig. 116), that coils itself and emits an ill-smelling
fluid when disturbed ; and the flattened, usually brownish or
pale greenish slender centipeds or hundred-legged worms
(fig. 117). In both kinds the body is plainly composed of
rings or segments, but while in the centipeds there is but
160 FIRST LESSONS IN ZOOLOGY.

one pair of legs on each body-ring, in the thousand-legged
worms or millipeds there are two pairs to each segment.
The millipeds feed on vegetable matter, although they
may take some dead animal matter, while the centipeds
which can run rapidly, are predaceous, catching and kill-

 

Hic, 116, Fic. 117,
Fic. 116.—A galley-worm (milliped), dus sp. (Natural size; from speci-
men.)
Pic. 117,-- \céntiped, Scodopendra sp. (Natural size; from specimen.)

ing insects, snails, earthworms, etc. Centipeds have the
first pair of legs modified into a pair of poison-claws,
which are bent forward so as to lic near the mouth. The
common ‘skein centiped”’ (fig. 118) is yellowish in color
and has fifteen pairs of legs, long, forty-segmented an-
tenna, and nine large and six small or dorsal segmental
WORMS, CRAYFISH, CENTIPEDS, ETC. 161

plates. The true centipeds (fig. 117), have twenty-one
to twenty-three body-rings, each with a pair of legs, and
the antenne have seventeen to twenty segments. They
live in warm regions, some grow-
ing to be very large, as long as
twelve inches or more. The bite
or wound made by the poison.
claws is fatal to insects and other
small animals, their prey, and
painful, or occasionally even
dangerous, to man. The popular
notion that a centiped stings with
all of its feet is fallacious.
Galley-worms (millipeds) (fig.
116) can easily be kept alive in
shallow glass vessels with a layer
of earth in the bottom, and their
habits and life-history be studied.
They should be fed sliced apples,
green leaves, grass, strawberries,
fresh ears of corn, etc. They are
not poisonous and may be handled
with impunity. They lay their
eggs in little spherical cells, or
nests, in the ground. An English
species, of which the life-history
has been studied, lays from sixty
to one hundred eggs at a time. Fic. 118.—The skein centi-
The eggs of this species hatch in re ee
about twelve days. and conservatories. (From
Centipeds and millipeds com- Manlove)
pose the class Myriapoda of the branch Arthropoda.

 
CHAPTER XII
INSECTS

Insects are the most familiar and abundant of land ani-
mals, and number more species than are known of all
other kinds of animals together. Nearly 400,000 differ-
ent species of living insects have so far been found, and
thousands of new ones are discovered each year. Beetles,
moths and butterflies, flies, wasps, bees and ants, dragon-
flies, plant-bugs and grasshoppers are to be found in the
vicinity of any schoolroom, and the interesting habits of
insects, their great variety and abundance, and the readi-
ness with which they may be collected, kept alive, and
studied, make them unusually fit animals for the special
attention of beginning students of zoology.

Our studies with the silkworm, moth, mosquito, dragon-
fly, and grasshopper have already made us acquainted
with the elementary facts concerning the body-form,
structure, and life-history of insects, while our later study
of the communal life of the honey-bee and ants will show
us the fascinating interest which the special study of cer-
tain of the more highly organized insects may have.

Insects are classified into various groups called orders,
of which all the beetles constitute one, the moths and
butterflies one, the two-winged flies one, the ants, bees,
wasps, etc., one, and so on. But to learn much about
this classification, which constitutes systematic entomol-
ogy, requires a great deal of time and persistence on ac-

162
INSECTS 163

count of the great numbers of species concerned. There-
fore it may well be postponed until after we know more
of the life of some of the more familiar and interesting
insects. A good way to begin the study of systematic
entomology is to make a collection of insects of all kinds.
Directions for collecting and preserving insects are given
in Appendix B. The best book of insect classification is
Comstock’s ‘‘ Manual of Insects.”’

Pond and brook insects. —There is space in this book
to take up but few of the many interesting insects which
can be readily found and observed. Among the most
available are the common pond
and brook insects. Land insects
live under most diverse conditions,
that is, on the ground, in the
leaves, fruits, and stems of plants,
in the trunks of trees, or in dead
wood, in the soil, in decaying
animal or plant matter, and as
parasites on or in other animals,
but the aquatic kinds are almost
wholly limited to fresh water. A
few species live on the surface of
the ocean, however, and a few
others on the water-drenched rocks
and seaweeds between tide-lines.

On the under side of stones, in
brook ‘‘riffles,’’ and in pools and eon

_ FIG, 119,— Young (nymph) of
watering-troughsnottoo frequently Mayfly, showing (g)_ tra-
used are to be found commonly heal gills. (From Jenkins

and Kellogg.)
the young, i.e., nymphs (fig. 119),
of Mayflies, recognizable by the rapidly vibrating flap-
like tracheal gills along each side of the flattened delicate
body, three pairs of legs, and two or three long, slender
filaments projecting from the tip of the abdomen. Those

 

 
164 FIRST LESSONS IN ZOOLOGY

found in ponds or other quiet water may be kept alive
for some time in the school aquarium (see p. 332). Ex-
amine a live specimen in water in a watch-glass with a
magnifier. The body-wall is so transparent that many of
the internal organs can be seen. Note especially the beat-

 

\

Fic. 120,—A Mayfly (adult), (Natural size; photograph by the author.)

ing of the heart, a slender tube running along the middle
of the back. See the dark air-tubes (trachea) running out
into the thin gills, and note the rapid vibration of these
gills to keep in contact with fresh water. The young May-
flies feed on minute organisms such as diatoms and other
alge. They live as nymphs for a year, or even two or three
ycars in some species, and then crawl out of the water
on a stone or plant-stem, or come simply to the surface
INSECTS 165

when the delicate, gauzy-winged adult quickly issues.
The adult Mayfly (fig. 120) takes no food and lives onlya
few hours, or at most a few days. It has the shortest
adult stage of all insects. The female drops her eggs
into the water.

Firmly attached to stones, especially large ones, in
swift parts of the stream, may be found small cases, or
houses, composed of many small pebbles fastened together
with silk (fig. 121). In more quiet places in the stream,

 

Fic, 121.—Two cases Fic. 122. —Two cases of cad-
or ‘‘houses”’ of cad- dis-worms, with the insects
dis-worms. (Natural showing head and thorax
size; from speci- projecting. (Natural size;
mens.) from specimens.)

either attached to stones or resting on the bottom, or
sometimes floating in the water, may be found elongate
cases, an inch to two inches long, made of bits of wood
fastened together with silk, or of bits of pine-needles, or
even grass stems tied cleverly together by silken threads,
or it may be tiny cornucopias composed of sand grains. All
these are the cases of the caddis-worms or case-worms,
and a caddis-worm itself may be found snugly con-
cealed in each case. Find cases with the head and fore
part of the worm projecting (fig. 122) and cases moving,
166 FIRST LESSONS IN ZOOLOGY

dragged by the slowly walking caddis-worm. Pull a
worm from its case and examine it. How does it hold
itself so firmly in the case? What is the case for? Why
is the head and front part of the body so much harder
than the rest? How does the caddis-worm breathe?

Not all of the caddis-worms live in cases, and some
which make cases do not remain in them all of the time,
so that you may sometimes find them crawling about on
the stones. Some of these make tiny nets of silk stretched
between two near-by stones. These nets are ‘‘ usually
funnel-shaped, opening up-stream, and in the center of
them there is a portion composed of threads of silk ex-
tending in two directions at right angles to each other,
so as to form meshes of surprising regularity. It is as if
a spider had stretched a small web in the water where
the current is swiftest.’’ In these nets are caught bits of
organic matter which serve as food for the insects. The
caddis-worms which build these nets live in rude cases,
on the under sides of stones, composed of an inner silken
tube partly covered with little pebbles.

All these creatures are the young, or larvee, of caddis-
flies, which, when adult, are moth-lke flying insects,
with four wings covered with hairs, among which are
distributed many flattened scale-like ones; the antenne
are very long and thread-like. The insects may be
found fluttering among the foliage, or alight upon it, at
the brook’s margin. Caddis-flies have a complete meta-
morphosis. When ready to pupate the caddis-worm
closes the opening of its case by spinning a silken sheet
across it or filling it with a stone. The opening is of
course not absolutely closed, space being left for the
ingress of water which carries oxygen to the pupa within.
This lies quietly in its case until ready to emerge as the
winged caddis-fly, when it crawls out of its case, up on some

plant stem or stick and there moults the pupal cuticle.
INSECTS 167

In quiet pools in the brook and in almost any pond
may be found water-bugs and water-beetles. Collect
various kinds alive and keep in the schoolroom aquarium
(p. 332). Running swiftly about on the surface may be
seen rather large, blackish, narrow-bodied, long-legged
insects known as water-striders or pond-skaters (fig. 123).
When at rest they hold
the front pair of legs,
which are shortand stout,
projecting forward close
to the head, ready to
grasp and hold small in-
sects, the blood of which
they suck by means of
a sharp, strong, pierc-
ing beak. Their feet
make small dents or
dimples in the surface
film, but do not break

through. Do they ever FIG. 123--—A water-strider, Wygrotrechus
g y sp. (From Jenkins and Kellogg.)

 

dive or swim in the
water? Can they leap? Are they winged or wingless?
The immature water-striders have the body much shorter
than that of the adult. To be found also at the surface
of the pool are small, oval, flattened, shining black insects
that dart swiftly about in curving paths on the water.
These are whirligig beetles. Do they run on the water
or swim? Do they ever dive and swim beneath the sur-
face? Examine one with a magnifier, and note that it
has four compound eyes instead of two, the usual num-
ber in insects. Where is the extra pair situated? Note
the peculiar shape of the legs. What are the legs
specially fitted for?

Swimming about below the surface may sometimes be
found large, shining, black beetles (fig. 124) from half an
168 FIRST LESSONS IN ZOOLOGY

inch to an inch and a half long. There are two principal
kinds, the predaceous diving-beetles, which kill and eat
other insects, and the water scavenger-beetles which feed
on decaying vegetation inthe water. The first have slender
thread-like antennz, while the second have antenne
with thickened or club-like tips. As neither kind has

 

 

 

Fic. 124.—Predaceous diving-beetles (large) and back-swimmers in water.
(Slightly less than natural size; drawn from living specimens.)
gills both have to come to the surface to get air, but
they always carry down with them a supply sufficient to
last some time. They do this in two different ways.
The predaceous diving-bectles force the posterior tip of
the body above the surface (they always hang head
downward when at the surface) and slightly lift the tips
of the horny black wing-covers which lie on the back.
Air rushes in under the wing-covers and is held there by
the closing of the tips. The breathing pores or spiracles
INSECTS

169

of the beetle are situated along each side of its back,

underneath the wing-covers, so that
the air held there readily enters the
body. The water scavenger-beetle
when at the surface keeps its head
uppermost. It carries most of its air
supply on its under or ventral sur-
face, where it is held in a coat of
The air gives the
under side of the beetle a_ shining
silvery appearance. It is held by the
fine hairs by virtue of the surface
film. If you dip a bit of cloth having
a pile, as velvet, into water, you will
see that it retains underneath the water
a nearly complete coating of air. The
under side of the water scavenger-
beetle is covered in places with a
fine pubescence which acts like the
pile of the velvet.

fine short hairs.

 

Fic. 125.—Water-tiger,
the larva of the pre-
daceous_ water-beetle,
Dyticus sp. (Natural
size; from specimen. )

The water-bugs are about half an inch long, and are

grayish or black and white in color.

There are two com-

 

Fic. 126.—A water-boatman, Corisa
sp. (Twice natural size; from
Jenkins and Kellogg.)

mon kinds, one called back-
swimmers (fig. 124), which
swim with under side upper-
most, and have the back
black with large creamy
patches, the other called
water-boatmen (fig. 126),
which swim with back upper-
most, and are greenish gray,
with fine black mottling.

Both kinds come to the surface for air, and carry a supply

of it down with them.

Observe this, and note the differ-

ence in the disposition of the air (revealed by its silvery
170 FIRST LESSONS IN: ZOOLOGY

 

y),

Tic. 127.—Swallow-tail butterflies, Papilio rutulus, (One-half natural
size; drawn from life. )
INSECTS I7I

appearance) in the two kinds. What is the favorite rest-
ing position of each? Which pair of legs do the back-
swimmers use for oars? Which pair do the water-boat-
men use? Water-bugs are predaceous, sucking the blood
of captured insects by means of a piercing beak.

Moths and butterflies.—So many good books have

 

ayy Jo (varry) rvyidiajyeg—'gzr ‘oT

vasojoyd ‘azts

(-royne ayy fq yd

‘spat vitoasypD ‘YOU-JUTeM [eBoI

 

 

 

 

yempen)

been written about the life of moths and butterflies, and
so surely ought one or more of these to be found in the
172 FIRST LESSONS IN ZOOLOGY

school library, that I shall make no attempt here to do
more than call the attention of teacher and pupils to the
admirable opportunity these insects afford for field and

 

(Natural size;

photograph by the author. )

129.—Adult (imago) of the regal walnut-moth, Cotheronia regalis.

 

 

 

Fic.

 

schoolroom study. Some of the most beautiful butterflies
are common all over the country, and their eggs, or
caterpillars at least, can certainly be found and reared in
INSECTS 173

simple breeding-cages (for directions for making see p.
332) in the schoolroom. Such are the black and yellow
swallow-tail butterflies (fig. 127), the black and red-brown
monarch or milkweed butterfly, the somber mourning-
cloak, and the abundant cabbage-whites and sulphurs of the
fields. The same is true, too, of some of the largest and
most beautiful moths. The great
silken cocoons of the cecropia and
polyphemous moths can be found in
winter, when the branches are bare,
in orchard trees. They can be kept
in the schoolroom, where the issuance
of the great moth can be carefully
watched; how the wings gradually
unfold and expand and dry, and the
colors grow brighter and sharper, until
the splendid creature is ready to take
wing in search of food or mates.

In the recent wide interest which
the popular study of animals has at-
tained, birds and moths and butterflies Fic. 130.—Grape-vine
have been given special attention by oe ae
the writers of books, and by means of (Natural size; drawn
pictures made from photographs of the a ee \
live animals many finely illustrated
accounts of the life of various birds and insects have been
published. Scudder’s ‘‘Every-day Butterflies,’’ Mary
Dickerson’s ‘‘Moths and Butterflies,’’ and Eliot and
Soule’s ‘‘Caterpillars and their Moths’’ are admirable
examples of such books. Reference to them will give
suggestions for an unlimited amount of observation.
Scudder’s ‘‘ Life of a Butterfly ’’’ is a detailed account of
the monarch butterfly. Holland’s ‘‘ Butterfly Book ’’ is
a finely illustrated manual of our butterflies by the use of
which any butterfly specimen can be named.

 
174 FIRST LESSONS IN ZOOLOGY

Aphids, ants, and aphis-lions.-—On the new shoots and
buds of roses, on fruit-trees, or on cultivated plants in the
greenhouse or garden may often be found many of the
small, soft-bodied, greenish or purplish insects familiarly

 

(Natural size; photograph by the author.)

Fic. 131.—Cecropia moth.

 

 

 

 

known as plant-lice, green-fly, or aphids (fig. 135). They
usually occur clustered together in large numbers. Most
of the individuals are wingless and of various sizes, but a

few winged specimens, all of one size, will probably be
INSECTS 175

found. By observing a colony of aphids from day to day
it may be discovered that the young are born alive, and
are without wings; that feeding is accomplished by a tiny
sucking beak, which is thrust into the soft, fresh, plant
tissue to suck up the sap; and that each aphid has a

 

 

 

Fic. 132.—A family of forest tent-caterpillars (CU/stocam pa disstria), rest-
ing during the day on the bark, about one-third natural size. (Photo-
graph from life by M. V. Slingerland.)

pair of curious little tubes on its back, which are called
honey-tubes. It was long supposed that the honey-dew,
a sweetish secretion which the aphids produce, came from
these tubes, but it is now known to come from the ali-
mentary canal. Several generations of aphids are born
alive during the summer, but in the autumn the females
176 FIRST LESSONS IN ZOOLOGY

each lay one or a few eggs, which usually last through
the winter, new ‘‘stem mothers’’ hatching from them
the following spring. | When the aphids get too crowded
on a plant or tree some winged individuals are produced

 

 

 

 

 

Fic. 133.—Moths of the peach-tree borer, Savninoidea exitiosa, natural size;
the upperone and the one at the right are females, (Photograph by M.
V. Slingerland.)

which can fly to another food-plant and establish a new
colony.

It will almost certainly be noted during the course of
observing that the aphids are visited by ants (fig. 135), and
by careful watching it may be seen that these ants lick up
the sweet honey-dew secreted by the aphids. So much
do the ants like this honey-dew that sometimes they take
special care of a colony of aphids, driving away their
enemies, and visiting them regularly to feed. Aphids
have been called the cattle of the ants.
INSECTS 177

 

 

 

 

 

Fic. 134. sie a worms, larvee of the moth, Leucania unipuncta, on corn.
= ~iatural sieoy-photoginph Ly 3 M. V. Slingerland.)
178 FIRST LESSONS IN ZOOLOGY

 

™~
Fic, 135.—Rose aphids and ants. (Natural size; from life.)

 

Pic. 136,—The volden-cyed or lucce-winged fly (CArrsopa); adult, eggs, larva
(aphis-lion), and pupal cocoons. (Natural size; from specimens. )
INSECTS 179

But other visitors still may be noted, and ones which
make anything but friendly calls. They, too, come for
food, the soft juicy body of the plump little aphid.
Among the most interesting and fatal of these carnivorous
visitors are the aphis-lions, the fierce larve of the beau-
tiful golden-eyed, lace-winged fly (fig. 136). These may
be recognized by their long, slender, pointed mandibles
projecting far in front of the head. These mandibles are
each grooved along the inner side. When the sharp tips
are thrust into the soft body of an aphid its blood runs
along the groove into the mouth of the lion. The eggs
of the aphis-lion are laid on the tips of slender stalks, to
protect them from wandering predaceous insects, includ-
ing other aphis-lions. When the larva has made its full
growth it spins a spherical silken cocoon, within which it pu-
pates. Finally, there emerges the beautiful slender-bodied
adult, the lace-winged fly, with four large, gauzy, green
wings, and eyes which shine with a fiery golden color.

Cicadas, katydids, crickets, and their sound-making
organs.—Insects familiarly known because of their shrill
summer song are the periodical cicadas, or seventeen-year
locusts. The second name is really no exaggeration.
Although the adult cicadas live in trees and lay their
eggs in small slits cut in the twigs, the young, on hatch-
ing, drop to the ground and dig down to the roots of the
tree. There they suck the juices from the roots by means
of a strong piercing beak until the beginning of the
summer of the seventeenth year. They then crawl up to
the surface of the ground, and, clinging usually to the tree
trunk, moult and transform into the fully winged adult,
with its shrill song. This is made by a curious musical
apparatus on the under side of the body (fig. 137), consist-
ing of a tympanic membrane or thin plate which can be set
into vibration by a muscle attached to its center. It is
practically a musical instrument of the type of the tin pan
180 FIRST LESSONS IN ZOOLOGY

with a string fastened to the middle of the bottom. There
are other species of cicadas besides the seventeen-year-old
kind, with shorter lives, a common one being the familiar
harvest-fly or dog-day locust, which requires only two

 

Fic, 137.—The seventeen-year cicada, Creada seplendecim; the specimen at
left showing sound-making organ; 7.f, ventral plate; 7, tympanum.
(From specimens. )

years for its development. This is large, and black and

green in color, while the seventeen-year cicada is smaller,

and black and reddish-brown.

Other insects conspicuous for the sounds they make are
the katydids and crickets. The loud sounds of insects
are not made bya ‘‘voice’’ that is, by vocal cords set
into vibration by the breath. In the katydids and crickets
the familiar shrill sounds are made by rubbing together
the bases of the front wings, which are specially modified
for this purpose. The veins are thickened and rough-
ened by little transverse ridges forming a sort of scraper
or rasp, so that the membranes are set into strong
vibration when the base of one wing is scraped or rubbed
over the base of the other. Only the males are provided
with these musical organs.

There are about a dozen species of tree and bush katy-
INSECTS 181

dids in the United States, all with broad, green, leaf-like
front wings, long, slender antenne and large, leaping hind

legs (fig.138). The large, flat, seed-like eggs (fig. 138) are

 

Fic. 138.—Katydid, and leat with eggs of katydid along edge. (Natural
size; from specimens. )

laid overlapping each other in regular rows along a twig
or the edge of a leaf, and the young undergo an incom-
plete metamorphosis. In both immature and adult stage
katydids feed on the foliage of trees. The crickets are
182 FIRST LESSONS IN ZOOLOGY

closely related to the katydids, although differing much
from them in appearance. They are black, and live in
holes in the ground or in concealed places in houses, coming
out at night to hunt for food and to ‘‘sing.’’ The eggs
are laid in autumn and are hatched the following spring.
Obtain some crickets and distinguish the males from
the female. The female has a long pointed ovipositor
(egg-laying organ) lacking in the males, while the bases
of the fore wings of the male are peculiarly modified.
Examine carefully these modified
parts. Under the microscope the

\ principal vein, which extends di-
| agonally across the base of the

| wing, will be seen to be furnished
\ with transverse ridges like a file
(fig. 139). On the inner margin
of the wing, a short distance from
the base toward the end of the
principal vein, is a hardened por-
y tion which may be called the
IG, 139.—Cricket and file scraper. Each fore wing is there-

(part of the sound-making G :
SppaEshe’. (Cricket natu- fore provided with a file and

 

ral size; the fie greatly scraper. When the cricket wishes
magnified; from specimens, ) : F
to make his call he elevates his
fore wings at an angle of about forty-five degrees with
the body; then holding them in such a_ position that the
scraper of one rests on the file of the other, he moves
them back and forth laterally, so that the two parts rasp
upon each other. This throws the wing membranes into
vibration and produces the call.

The solitary bees and the digger-wasps.—The soli-
tary bees are so called because of their manner of living
apart and not in communities as do the social bees, like
the bumble- and honey-bee. Among them there are no
neuter-worker individuals, each female making a nest for
INSECTS 183

her own eggs and doing for herself all the work of
burrowing the nest tunnel, and provisioning it with
food for the young. These solitary bees are of many
kinds, and exhibit a wide variety of nest-making
habits. For example, the mining-bees
make a tunnel in the ground lined with
a sort of glaze, and more or less branched,
each branch ending in a cell in which
a single egg is laid and a small mass
of pollen and nectar paste stored to serve
as food for the bee grub. The carpenter-
bees tunnel into dead or live wood. One
of these, known as the little carpenter-bee,
bores into dead twigs of sumac or the
canes of brambles, or other soft-pithed
plants, making a long tunnel through the
pith (fig. 140). At the bottom of this an
egg with a pellet of pollen paste is de-
posited. With some pith chips a partition
is made across the tunnel above the egg;
another egg and food pellet are put in on
this second story, and so on until the
tunnel is divided into half a dozen cells.
The mother bee then rests in the space
above the last cell and waits for her chil-
dren to grow up. The lower one hatches .
first; after attaining its growth it tears py patentee
down the partition above it, and then or burrow of
5 ; carpenter - bee.
waits patiently for the one above to do (Natural size ;
thesame. The two now wait forthe third from __speci-
to mature, and so on. Finally, when the ne
last one in the top cell has come out, the mother leads
forth her fullfledged family for a flight into the sunshine.
After the last of the brood has emerged from its cell the
substance of which the partitions were made, and which

 

 

 

 

 

 

 

 

 
184 FIRST LESSONS IN ZOOLOGY

has been forced to the bottom of the nest by the young
bees making their escape, is cleaned out by the family,
the old bee and the young ones all working together.
Then the nest is ready to be used again by one of the
bees.

Some solitary bees make cells for their young out of
neatly cut pieces of leaves. The common leaf-cutter bee
first makes a tunnel in wood, often selecting that which is
partly decayed; it then proceeds to build a thimble-
shaped tube at the bottom of the tunnel. For this pur-
pose it cuts from the leaves oblong pieces, each of which
forms a part of aside and the bottom of the thimble-
shaped tube. The tube being completed the bee par-
tially fills it with a paste of pollen and nectar upon which
she then places an egg. Lastly, she cuts several circular
leaf pieces, the diameter of which is a little greater than
the diameter of the tube, and forces them into the open
end of it, thus making a tightly fitting plug. Usually
several cells of this kind are placed end to end in a bur-
row; and sometimes many bees will build their nests to-
gether in the same piece of wood.

For an account of the life of the bumble-bees and
honey-bee, see Chap. XX.

The digger-wasps differ from the social kinds, such as
the yellow-jackets and hornets, just as the solitary bees
do from the honey-bees. There are no neuter-worker
wasps, but each female makes a separate nest and pro-
visions it by her own labor. The stored food consists, not
of pollen and nectar, as with the bees, but of paralyzed
or killed insects or spiders. In some cases a new nest is
made for cach egg. ‘‘ The nests may be made of mud, and
attached, for shelter, under leaves, rocks, or eaves of
buildings, or may be burrows hollowed out in the ground,
in trees, or in the stems of plants. The adult wasp lives
upon fruit or nectar, but the young grub or larva must have
INSECTS 185

animal food, and here the parent wasp shows a rigid con-
servatism, each species providing the sort of food that has
been approved by its family for generations, one taking
flies, another bugs, and another beetles, caterpillars, grass-

 

 

 

 

 

Fic. 141.—Nesting grounds of Ammophila in the salt marshes of San
Francisco Bay. (From nature.)

hoppers, crickets, locusts, spiders, cockroaches, aphids,
or other creatures as the case may be.

‘“«The solitary wasps mate shortly after leaving the
nest, in the spring or summer. The males are irrespon-

=?
SAT

a ;

      
   
    
 

  

   

 

a, c

Fic. 142.—Ammophila putting inch-worm into nest-burrow. (Natural size;
from life.)

sible creatures, aiding little, if at all, in the care of the

family. When the egg-laying time arrives the female

secures her prey, which she either kills or paralyzes,

places it in the nest, lays the egg upon it, and then, in
186 FIRST LESSONS IN ZOOLOGY

most cases, closes the hole, and takes no further interest
in it, going on to make new nests from day to day. In
some genera the female maintains a longer connection
with her offspring, not bringing all the provisions at once
but returning to feed the larva as it grows, and only
leaving the nest permanently when the grub has spun its
cocoon and becomes a pupa.

‘«The egg develops in from one to three days into a
footless maggot-like creature, which feeds upon the store

 

Fic. 143. Pic. 144,
Fic. 143.-—Nest-burrow of Ammophila with food for the young (paralyzed
inch-worms) in bottom, and burrow nearly filled. (From nature.)

FIG. 144.—Ammophila bringing covering bit of salt incrustation to put over
stored and filled nest-burrow. (Natural size; from life.)

provided for it, increasing rapidly in size, and entering
the pupal stage in from three days to two weeks. In the
cocoon it passes through its final metamorphosis, emerg-
ing as a perfect insect, perhaps in two or three weeks,
or, in many cases, after the winter months have passed
and summer has come again. Probably no solitary wasp
lives through the winter, those that come out in the spring
or summer perishing in the autumn.”’

The nest-making habits of any solitary wasp when
INSECTS 187

carefully observed will prove to be of absorbing interest.
The author has often watched individuals of one kind (a
species of the genus Asmmophila) at work on the salt
marshes of San Francisco Bay near Stanford University.
These marshes (fig. 141) are nearly covered with a dense
growth of a low fleshy-leaved plant, but here and there
are small, perfectly bare, level sandy places, which shine
white and sparkling in the sun because of a thin incrusta-

 

 

 

 

 

Fic. 145.—The quince curculio (a beetle), Conotrachelus crategi, natural
size and enlarged. (Photograph by M. V. Slingerland.)

tion of salt. In September these bare places are taken pos-
session of by many female Ammophilas, which make short
vertical nest-burrows all over the ground. An Ammo-
phila having chosen a site for its nest bites out a small
circular piece of the salty crust, and with its strong jaws
digs out bit by bit a little well. Each pellet dug out is
carried by the wasp, flying a foot or two from the mouth
of the tunnel, and dropped. To emerge from the hole
188 FIRST LESSONS IN ZOOLOGY

the wasp always backs upward out of it and while digging
keeps up a low humming sound. After the tunnel is dug
about three inches deep she covers up the mouth with a
bit of salt crust or little pebbles, and flies away. After
some minutes she comes back carrying a limp inch-worm
about an inch long, which she drags down into the nest
(fig. 142). Away she goes again and soon returns with
another inch-worm; repeating the process until from five

 

 

 

 

Fic. 146.—Immature stages of the quince curculio, Conotrachelus cratagt ;
at the left, the larva natural size and enlarged; at the right, the pupa.
The beetle lays its eggs in pits on quinces, and the larva lives inside
the quince as a grub; the pupa lives in the ground. (Photograph by
M. V. Slingerland.)

to ten caterpillars have been stored in the tunnel. All

these are alive, but each has been stung in one of its

nerve-centers (ganglia) so that it is paralyzed. Finally,
down goes the mother Ammophila and lays a single egg,
attaching it to one of the paralyzed caterpillars. She
then fills the tunnel with pellets of earth, carefully chew-
ing up the larger pieces so as to make a close, well-
packed filling (fig. 143). Lastly, she carefully smooths
off the surface and puts a small flat piece of salt crust on
INSECTS 189

top (fig. 144), so that the site of the tunnel shall be as
nearly indistinguishable as possible.

Ammophilas are common all over the country, and the
nest-building of various species has been watched by other
observers. The use by an indi-
vidual Ammophila of a small
pebble, held in the jaws, as a
tool to pound down and smooth
off the earth has been twice
recorded, once in Wisconsin and
once in Kansas. These are per- Fic. 147.—The plum curculio,
haps our only records of the use (“ir ee oe
of a tool by an insect. (Photograph by M, V. Slinger-

Very interesting accounts of ee)
the habits of various digger-wasps may be found in ‘‘ The
Solitary Wasps,’’ by George W. and Elizabeth G. Peck-
ham; also in ‘‘ Insect Life’? by Fabre.

The best general reference-book for American students
of insects is Comstock’s ‘‘ Manual for the Study of In-
sects.’’ ‘‘ Insect Life,’’ by the same author, gives prac-
tical directions for much interesting observational work
on habits and external structures. Howard’s ‘‘ Insect
Book ’’ is recent and interestingly written.

 

 

 

 

 

 
CHAPTER XIII

SPIDERS AND THEIR WEB-MAKING

The abundance, variety, wide distribution, and inter-
esting habits of spiders, and the ease with which they may
be kept alive and observed in captivity make them excel-
lent subjects of observation by young zoologists. The
bite of no one of the common small spiders of house and
field and garden causes any more pain than the prick of
aneedle. The bite of the tarantula and of a few of the
large running spiders may cause some pain, but in study-
ing spiders there is no necessity of being bitten at all.

The animals should be observed both in the schoolroom
and out-of-doors. Onecan get acquainted with the make-
up of the spider body and with some of the feeding habits,
and even some of the spinning, in the schoolroom. The
rearing of spiders from eggs and the observation and
growth of the ‘‘spiderlings’’ can also be managed
in the schoolroom. But the study of spiders’ homes,
the different kinds of webs they spin, with the processes
of web-building, and the general habits of the various
common kinds must, most of it, be done in the field or
garden or along the roadside; in a word, out-of-doors.

Collecting spiders.—To collect live spiders for the
schoolroom one should provide himself with a number of
empty pill-boxes, cap-boxes, or other small paper-,
wooden-, or tin-boxes with well-fitting cover. Each of
these will serve as collecting tool for one spider, and as
cage to keep it in until the schoolroom is reached. Search

1yO
SPIDERS AND THEIR WEB-MAKING 19gt

for spiders in or near their webs, in the corolla of flowers,
on the bark of trees, under stones and sticks on the
ground, and (for tarantulas and other spiders with tubu-
lar nests in the ground) in their burrows. Spiders living on
webs, flowers, trees, etc., are very prone to drop quickly
to the ground when disturbed. Take advantage of this
and be ready to catch a falling spider in a pill-box,
quickly clapping the lid on. Use the pill-box and lid as
catching equipment (fig. 148); you will soon get expert in
the work. Small spiders, especially those in webs or
flower-cups, can be caught with perfect impunity in the

 

Fic, 148. Fic. 149.

Fic. 148.—Catching a spider. (After Jenkins and Kellogg.)
Fic. 149.—Spider dropping from a pencil supported by suspending line.
(After Jenkins and Kellogg.)

hands. But there is always danger of crushing the soft
body of the creature, or pulling off a leg or two in hand-
ling. Trust chiefly to manipulation of the box and lid.
There need be no holes in the box for the admission of
air, the boxes being by no means air-tight. The silken
egg-sacs or cocoons of spiders, if recognized, may also be
collected, and the young spiders reared in the school-
192 FIRST LESSONS IN ZOOLOGY

room. Some thoroughly interesting experiments may be
made with them.

The make-up of the spider body.—Have a number of
common house-spiders (readily found in wood-sheds,
stables, attics, etc.), and of ground-spiders (to be found
under stones and boards) alive in glass jars. Put some
small live insects in the jars for food. Observe the be-
havior of the spiders. If they capture the insects note
what is done with them. Is there any difference in the
behavior of the two kinds of spiders? Do they spin silk
about their prey? If they spin silk about the prey do
they spin any more? Do they eat the whole body of the
captured insect? Where does the silk come from? Take
out from the jar one of the house-spiders on the end of a
pencil. It will drop, not free, but attached to a delicate,
almost invisible, silken thread, which issues from the
posterior tip of the body (fig. 149). By quickly lifting the
pencil before the spider reaches the table or floor the
holding thread may be observed.

Kill some of the larger individuals in a killing-bottle
(see p. 335) and carefully examine them. How many legs
has a spider? A pair of short processes
which look, at first glance, like legs and
are situated in front of the first pair of
true legs, are feelers or palpi—not the
same kind of feelers as the antennz of
insects, but feelers belonging to the
Fic. 150.—The eyes mouth. Into how many principal parts

and jaws, showing . ee

filx and fang of a 18 the body divided? ‘These parts have

eae ee the same name as those of the crayfish.

ins and Kellogg. ) , ‘
The spider body is really built on the
segmented plan (like the worms, crustaceans, centipeds,

 

and insects), but the segments have grown together so
that the lines or sutures between them are obsolete. To
which part of the body are the legs attached? Are there
SPIDERS AND THEIR WEB-MAKING 193

any antenne? The eyes of spiders are simple (not com-
pound as in the insects and crustaceans), and they vary
in number and size and arrangement in the different
kinds. Find the mandibles or jaws; with a pin press
them apart and examine them. How do they work?
Note that each jaw (fig. 150) is composed of a firm,
smooth, sharp-pointed tip called the fang, and a thicker
hairy basal part, the falx. In the falx is the tiny poison-
sac, from which the poison runs through the fang and out
through a hole near the point. All
spiders have poison-sacs, but with
only a few of the larger ones is enough
poison introduced into the wound to
make a bite at all painful to us.

Examine now the spinning-organs.
At the posterior tip of the abdomen
may be seen a few small finger-like
projections, the spinnerets (fig. 151).
Each of these movable spinnerets gq.’
bears on its surface many very small
papille, the spinning-tubes (fig. 151).
These can be seen by examining a
spinneret under the microscope. In Fic. 151.—The six spin-
spinning, a slender silken thread ee Bee een ge
issues from each of the spinning-tubes one spinneret magni-

2 fied (above) to show
on each spinneret. All of these fine the spinning “ spools”
threads unite to form one strong line  ortubes. (From Jenkins

r and Kellogg.)
which we see.

The hunting-spiders.—Some kinds of spiders spin
webs for catching their prey, while some do not, but
trust to pursuit by running and leaping. The house-
spiders with their cobwebs, the field-spiders with their
silken sheets among the grasses, and garden-spiders with
their geometrically regular orbs hung in the shrubbery,
belong to the web-weaving group. The black, swift

 
194 FIRST LESSONS IN ZOOLOGY

pursuers that lurk under stones, the fierce-eyed little
black and red fellows hiding on the bark of trees, and
the daintily colored crab-like ones lying quietly in flower-
cups, belong to the non-web-weaving group. We shall

 

Fic. 152.—A web-weaving spider. (Natural size; from life.)

first consider those of this second group, which we may
call the hunting-spiders.

Under stones or lurking in half-concealment elsewhere
on the ground may be readily found certain blackish,
rather hairy, spiders, mostly of large size (fig. 153).
These are the running spiders, and they catch their prey
by swift running. Their legs are long, the hindmost

 

Fic. 153.—A female running spider (Lycosida) carrying its egg-sac about
attached to its spinnerets. (Natural size; from Jenkins and Kellogg. )

pair being the longest. Some of these spiders have the
body, exclusive of legs, an inch or even more in length.
SPIDERS AND THEIR WEB-MAKING 195

A large one may be found, perhaps, dragging after it a
dirty white silken ball (fig. 153). This is the egg-sac,
which is strongly attached to the spinnerets of the female,
being carried about by her until the spiderlings hatch.
Issuing from the egg-sac they climb on the back of the
mother, and are thus further carried and protected by her
until they are able to care for themselves.

Upon fences, the sides of out-buildings, on the bark of
trees, or fallen logs, may be found certain small, robust,
short-legged spiders which move chiefly by sudden leaps.
These are the jumping spiders (fig. 154). They are usually
black, with red or other striking color-markings, and two
of the eight shining black eyes are much larger and more

  

Fic. 154. Fic. 155.
Fic, 154.—A jumping spider (Attidz). (From Jenkins and Kellogg.)
Fic. 155.—A crab-spider (Thomisidz}!. (From Jenkins and Kellogg.)

conspicuous than the others—much larger, indeed, than
the eyes of any other spiders of equal size, and they give
the jumping spiders a peculiarly threatening appearance.
These can walk sidewise or backwards with facility, but
are readily distinguished by their leaping and their big
eyes from the true crab-spiders described in the next
paragraph.

In the cracks and crevices of fence and bark, and on
plants, may be found certain short, broad, flattish, usually
greyish spiders, which can run sidewise or backward
more readily than forward. These are known as crab-
196 FIRST LESSONS IN ZOOLOGY

spiders (fig. 155). Some of them lie in wait for their
prey in flower-cups, being usually white and parti-colored,
so as to harmonize with the bright corolla. They are
rendered inconspicuous by this sort of color mimicry, and
small insects alight unsuspectingly within reach of them
as they wait. The front two pairs of legs in these spiders
are longer than the other two pairs, and ‘‘so bent that
the spider can use them when in a narrow crack.’’

The running spiders, jumping spiders, and crab-spiders
are the most easily found and easily recognized of those

 

 

Fic, 156,—Trap-door spider (California) with two burrows, one with door
open, one with door closed. (Natural size; from life and specimens. )

which do not spin webs to catch prey. But there are
other groups characterized by this habit, among them
the giant California tarantulas or Mygales, and the trap-
door spiders. The nests (figs. 156 and 157) of these
spiders are described in Chapter III, page 39.

The web-weaving spiders.—The webs or snares of
spiders present a great variety in form and type of con-
SPIDERS AND THEIR WEB-MAKING 197

struction. The webs made by the various individuals of
any one species of spiders are always alike, however;
indeed, each family of web-weavers has its own peculiar
type-plan of web construction, and as we could distin-
guish various families of
non-web-weaving spiders
by their habits of locomo-
tion, so we can distin-
guish the various families
of web-weavers by the
character of the webs. .
Most familiar to us
probably are the ‘‘cob-
webs’’ of the neglected
corners and byways of
the house and out-build-
ings. The family of cob-
web weavers is a large
one, and its species are
not restricted to an in-
door habitat, but many
spin their loose, irregular
webs in bushes. With
them all the web is a

tangled maze of silken
Fic. 157.—Burrow of trap-door spider

threads, mostly in the cut open to show interior. (One-half
form. of a flat or curved natural size; from specimen.)

sheet of silk, on the under side of which the spider stands
or runs, back downward. Sometimes the owner has a
silken nest in a crack near the web, and there is some-
times a short silken tube leading to the nest. The spiders
themselves are usually small and very slim-legged.
Examine a cobweb carefully. Note its irregular, un-
symmetrical character. Can its general sheet-like form
be made out? Are there vertical threads running to it

 
198 FIRST LESSONS IN ZOOLOGY

from above? Is the web sticky, i.e., are the threads of
the web sticky? Are they all sticky? (see description of
orb-webs). Are there any remains of insects in the web ?
Throw a house-fly in, and if the spider comes to it watch
carefully all the spider's movements. Does it run out on
the upper or under surface of the web? Does it swathe

 

 

Fic, 158.—‘ Turret” or above ground part of nest of turret-spider, (Natural
size; from specimen.)

the fly’s body with silk? Does it carry the fly to its nest
or to another part of the web to eat it?

A grade higher in point of symmetry of construction
are the snares of the funnel-web weavers. These are
spun in the grass of meadows, pastures, gardens, and
roadsides, and because of their lowly and obscure situa-
tion do not usually appear to be very abundant; they are,
in fact, the most abundant of all. Some dewy morn-
ing we are surprised to find the grass nearly covered with
SPIDERS AND THEIR WEB-MAKING 199

glistening webs. These are revealed to us by the tiny
drops of water, which, clinging to the silken threads,
reflect the sun’s rays, and make the otherwise almost
invisible webs very conspicuous. It is desirable to choose
a dewy morning or the first hour after the lifting of a
heavy fog for spider-web hunting. The webs are not
only easily found then, but are then especially beautiful.
The funnel-webs are horizontal concave silken sheets,

 

Fic. 159.—Argiope sp., a large orb-weaver (Epeiride). (Natural size;
from Jenkins and Kellogg.)

supported in the grass by strong silken lines or cables
attached to the grass stems and blades. They have at
one side a funnel-shaped tube running downwards and
opening near the ground. In this tube the spider lies in
hiding, and from it runs out upon the upper surface of the
web to seize its prey, or runs away when necessary from
out the lower end, escaping unseen on the ground among
the grass roots. The funnel-web weavers are long-
legged, usually brownish in color, very often of consid-
erable size, and with one of the pairs of spinnerets
unusually long. Note how the web is suspended by stout
supporting lines. Note the funnel-shaped tube, with its
200 FIRST LESSONS IN ZOOLOGY

upper and lower openings. Find a tube with the spider
in it. ° Touch the tube lightly with a pencil point, trying

 

Fic. 160.—Spider and its web in a rose-bush. (Photograph from life by
Cherry Kearton; from ‘Wild Life at Home,’ by permission of
Cassell & Co.)

to induce the spider to come out upon the web. Observe

its manner of escape.

A great advance in point of symmetry and elabora-
tion of design is shown by the round webs or orb-webs
(fig. 161). These are the most interesting as well as the
most beautiful of spider’s snares. They may be found
suspended between the branches of shrubby plants, or
SPIDERS AND THEIR WEB-MAKING 201

between the bushes themselves, in fences, in open door-
ways, or wherever in the garden a convenient framework
presents itself. They are characterized by their circular
outline, within which are disposed numerous radii and a
series of concentric circular or spiral threads. The cir-
cular snare is usually placed within an irregular triangle,
or quadrangle, or polygon, which is held in shape and
position by stout stay-lines fastened to the adjacent

 

a

 

 

 

 

FIG. 161. Fic. 162.

Fic. 161.—An orb-web of Argiofe; this web may be from one to two feet
in diameter. (After McCook.)

Fic. 162.—Diagram of (one-half) an orb-web; /-s, free space; s.s, spiral
space; c.s, central space; fz, free zone; 7.2, notched zone; /, hub,
(After McCook. )

branches, or fence-rails, or door-frames, or whatever
serves as a framework for it. The webs vary greatly in
size, the largest being sometimes a foot and a half to two
feet in diameter. The spiders which spin them are called
garden-spiders or orb-web weavers, and most of them are
highly colored, and have a nearly spherical abdomen.
They may be found ‘‘ hanging head downwards, usually
near the center of the net; others have a retreat near one
edge of the net, in which they hang back downwards.
While resting in these retreats they keep hold of some of
202 FIRST LESSONS IN ZOOLOGY

the lines leading from the net, so that they can instantly
detect any jar caused by an entrapped insect.”’

Find one of these orb-webs in good condition, i.e., not
torn and ragged, but new and complete. Examine it,
and note the regularity of its construction (fig. 162). Trace
the stay-lines to their attachments; note the shape of the
outer polygon; note the ‘‘ spiral zone,’’ i.e., that part of
the snare filled with lines laid down in apparently con-

 

Fic, 163.—Spider putting in foundation lines for an orb-web; the spider
shown at different positions in the work. The first (uppermost) line is
carried across by an air-current. (After McCook.)

centric circles; note that these are not separate circles,
but are spiral, and that the line composing it is contin-
uous; between the outer polygon and the spiral zone
there is a region crossed by the radii, but without other
lines, the ‘‘ outer free zone’’; between the spiral zone
and the center of the snare there is another zone free
from spiral or circular lines, or with these lines very far
apart, the ‘‘inner free zone’’; the central part or central
zone of the snare has a close spiral in it, and here the
SPIDERS AND THEIR WEB-MAKING 203

spider, if it has no side retreat, usually rests. Touch one
of the radii or one of the foundation lines with a pencil
point; touch the spiral with a pencil; a difference in the
character of the two kinds of lines is at once manifest.
The spiral thread is ‘‘sticky,’’ the radii and foundation
lines are not so; the web is made of two kinds of silk.
If a bit of the spiral line be examined under a magnifier
it will be seen that, ranged along the silken thread, like
beads on a string, are many tiny globules or drops. These
are a sticky, viscous sort of silk, which does not dry and
harden as the usual silk does. These sticky drops make

 

 

 

Fic. 164.—How the spider ‘swings round the circle” in putting in the
spiral line; R1...... 16 = radii I to 16; s, scaffolding line, to be torn
out; x, the spider in various positions, The spider crawls and drops
along the course indicated by the dotted line, holding the new sticky
line free from the old one. (After McCook.)

the spiral line much more effective as a snare. Throw an

insect into the web and observe the behavior of the spider.

If possible observe the spinning of an orb-web. A
bridge which has a metal or wooden fretwork on each
side affords a particularly good place to watch this. In
the square or diamond-shaped open spaces the spider can
be readily seen at work. It works in a regular way, put-
ting in first the foundation (fig. 163), and radial lines, and
204 FIRST LESSONS IN ZOOLOGY

then the spiral ones (fig. 164). Two sets of spiral lines
are put in, a first set, which is made from the center out-
wards, is not sticky, and serves as scaffolding upon which
the spider works when putting in the second set. The
latter is sticky and is put in from the outer part of the web
toward the center. The tem-
porary spiral or scaffolding is
torn out as the work of put-
ting in the sticky permanent
spiral progresses. The web
building includes a great deal
of interesting behavior on the
part of the spider, the delicate
manipulation of the viscid
lines, and the almost geomet-
rically accurate disposition of
the lines composing the snare,
combining to render the whole
performance little short of
marvellous.

There are other kinds of
webs spun by other kinds of
spiders. Indeed among the
orb-weavers alone there is a
great variety in the character
of the webs; some, for ex-

 

Fic. 165 —A long-legged spider,
Tetragnatha sp. on its web, ample, lack a sector of the

One-hi atural size: ff ife. ae A ‘
(One-half natural size; from life. ) circle, being otherwise con-

structed on regular orb-web plan; others are composed
of perhaps less than one-half a circle, although still with
radii, and with concentric arcs of circles in place of com-
plete circles in the spiral zone. Certain kinds of spiders
spin a peculiar broad line, or rather band, of curling silk,
which leads from the snare to the side retreat. Or they
make of this band of curled silk a central zone not com-
SPIDERS AND THEIR WEB-MAKING 205

posed of a spiral line but of a closed oval or circular shield.
The very small triangle spider spins a triangular web
(fig. 166), from which a main stay-line runs, upon which
the creature rests with a loop of the stay-line held between
the fore and hind legs. When an insect alights upon
the snare the spider looses the hold of the hind legs on
the stay-line and the web springs suddenly, further en-

 

Fic, 166.—The triangle spider, Ayptiotes sp. (California), with its web;
the spider rests on the taut guy-line, with a loop of the line held
between its fore and hind legs; when an insect gets into the web the
spider loosens the hold of its hind feet on the guy-line, thus allowing
the web to spring forward sharply and further entangle the prey.
(Web with spider on one-half natural size; spider below twice natural
size; from Jenkins and Kellogg.)

tangling the prey. Search should be made for these and
other kinds of webs.

There is another peculiar phenomenon to be observed
in connection with spider’s silk. On some bright warm
days there may be noticed many ‘‘ spider webs’’ or long
threads of spider silk, floating in the air, some of them at
considerable heights. Careful observation will show that
not only are ‘‘spider webs ’’ floating, but attached to
206 FIRST LESSONS IN ZOOLOGY

many of them are small spiders sailing or ‘‘ ballooning ”’
through the air. These are called ballooning or aero-
nautic spiders. Examine carefully the top of fence-posts
or other exposed raised points and you may be fortunate
enough to discover one of these about to make an ascen-
sion (fig. 167). It will be standing with its legs close to-
gether and straight, the body being thus lifted as high as
possible, and the tip of the abdomen pointing upward.

 

Fic, 167.—Ballooning spider ready to sail, (Natural size; after McCook.)

From the spinnerets (at the tip of the abdomen) are issu-
ing lines floating freely. These lines are gradually spun
out (being really drawn out by the pull of the wind) until
they become so long that the wind bears them off with
the spider attached to them. Spiders may make long
journeys in this manner, and get themselves widely dis-
persed from their original habitat. These adventurers are
SPIDERS AND THEIR WEB-MAKING 207

mostly young, and hence small individuals of various
species; but some adult spiders of small size are also
aeronauts.

Life-history of spiders.—The eggs of spiders are
inclosed in silken cases, or cocoons of various shapes.
Most common are the flattened circular or elongate kinds
attached to the under side of boards or stones. Some-

 

Fic. 168. Fic. 169.
Fic, 168.—Webs of young orb-web spiders on a large web of an old spider,
(After McCook. )
Fic. 169.—Assembly of young spiders just after issuance from cocoon,
‘‘balled”’ underneath a rose-leaf. (After McCook.)

times they are spherical or vase-shaped and are suspended
among the leaves. As already noted the females of
certain running spiders carry the egg-sac about attached
to the spinnerets.

The eggs hatch in from fifteen to thirty days in sum-
mer, but if laid in the fall may not hatch until the follow-
ing spring. The young rarely leave the egg-sac imme-
diately but remain in it for a period ranging from a few
days to several weeks. With some species the spider-
208 FIRST LESSONS IN ZOOLOGY

lings feed on each other, the stronger overcoming the
weaker and devouring them. When they issue, which
they do by cutting a hole in the cocoon, they look like
the adult spiders, but are
of course much smaller.
They are also usually
lighter in color, and with-
out the patterns and
markings which charac-
terize the species. As
they grow they moult
several times, but do not
acquire the final arrange-
ment of hairs, spines,
markings, etc., until the
last moulting.

Nothing more interest-
ing in spider life is to be
observed than the be-
havior of spiderlings that
Fic. 170.—Egg-cocoon of the labyrinth have just issued. The

spider, with sides removed to show =

egg-packets and chambers, (Two and first silk-spinning, the

one-half times natural size; after Snod- attempts at web-making
grass. ) : dD)

 

the gregarious habit lead-
ing to ‘‘balling "' (fig. 169) or ‘‘ snugging ’’ of the brood,
and the gradual dispersion and assumption of independent
life all offer a fascinating and readily accessible field of
observation.

The best book about the life of spiders is McCook’s
‘“ American Spiders and their Spinning Work.’ A
smaller book is It¢merton’s ‘‘ Life of Spiders,’’ and one
describing all of the common spiders of the Eastern and
Southern States is Emerton’s ‘Common Spiders.”’
CHAPTER XIV

FISHES, BATRACHIANS, AND REPTILES

The great branch of vertebrate or backboned animals
includes the classes of fishes, the batrachians, the rep-
tiles, the birds, and the mammals. All these possess a
bony (or cartilaginous) spinal column, which distinguishes
them from the invertebrates or backboneless animals.
In addition they possess a further internal bony skeleton
(cartilaginous in some fishes, as the sharks and sturgeons),
including in all but the most primitive forms two pairs of
appendages or limbs. In some these limbs are mere
rudiments, as in the snakes, where only a few (pythons)
show any external sign of them; but in most vertebrates
they are well developed organs of locomotion, appearing
as fins in the fishes, as legs in the batrachians, reptiles,
and most mammals, as wings and legs in the birds, and
as arms and legs in the monkeys and man. In almost
all vertebrates the blood is red, and is always confined in
a special circulatory system consisting of heart, arteries,
veins, and capillaries. Air is taken up by the gills or
lungs, to which the blood is brought to be purified, i.e.,
to give up its carbon dioxide and receive oxygen. The
nervous system is highly developed, with a large brain
and with complex and highly efficient sense-organs, as
eyes, ears, etc.

Except for the insects the vertebrates include most of
the animals we familiarly know. They are pre-eminently
the ‘‘ intelligent animals’’ (ants, bees, and wasps, and
some other insects and spiders are also, of course, in-

209
210 FIRST LESSONS IN ZOOLOGY

telligent), and hence their ways and lives have more in-
terest for us than those of the lower animals.

The fishes.—We have already studied (Chapter V) an
example of the class of fishes. The sunfish is common
in streams and ponds all over the country, and its habits
can be well observed by patient students. It lives in
quiet corners of brooks and rivers, preferably under a log
or at the root of an old stump. It is a beautiful fish,
shining ‘‘ like a coin fresh from the mint.’’ Its body is
mottled golden, orange, and blue, with metallic luster,
darker above, pale or yellowish below. Its fins are of
the same color. The tip of its opercle or gill-cover is
prolonged like an ear, and jet black in color, with a
dash of bright scarlet along its lower edge. Nearly all
of the thirty species of sunfish found in the United
States have this black ear-like opercle, but some have
it long, some short, and in some it is trimmed with
yellow or blue instead of scarlet.

The sunfish lays its eggs in the spring in a rude nest
it scoops in the gravel and over which it stands guard
with its bright fins spread, looking as big and dangerous
as possible. When thus employed it takes the hook
savagely, perhaps regarding the worm as a dangerous
enemy. The young fishes soon hatch, looking very
much like their parents, although more transparent and
not so brightly colored. They grow rapidly, feeding on
insects and other small creatures, and reach their growth
in two or three years. They do not wander far and
never willingly migrate. Students should verify this
account on the different species. A more exact study of
the nests of the different species and the fishes’ defense
of them would be a valuable addition to our knowledge.
The most striking traits of this fish are its vivacity and
courage. The sexes are similar in appearance and both

defend the nest.
FISHES, BATRACHIANS, AND REPTILES 211

Closely related to the sunfish are the various kinds of
bass, the ‘‘crappies,’’ the calico bass, the rock-bass, and
the large-mouthed and small-mouthed bass. All the
members of the sunfish and bass family are carnivorous
fishes, especially common in the Mississippi Valley.

Another family of many species especially common in
the clear, swift, and strong Eastern rivers is that of the
darters and perches. The darters are little, slender-
bodied forms, which lie motionless on the bottom, moving
like a flash when disturbed and slipping under stones out
of sight of their enemies. Some are most brilliantly
colored, surpassing in this respect all other fresh-water
fishes.

Unlike the sunfishes and the darters are the catfishes.
The catfish gets its name from the long feelers about its
mouth; from these also come its other names of horned
pout, and bull-head. It has no scales, but its spines are
sharp and often barbed or jagged and capable of making
a severe wound.

Remotely allied to the catfishes are the suckers, min-
nows, and chubs, with smooth scales, soft fins, and soft
bodies, and the flesh full of small bones. These little
fish are very numerous in species, some kinds swarming
in all fresh water in America, Europe, and Asia. They
usually swim in the open water, the prey of every carniv-
orous fish, making up by their fecundity or ability to
produce young in great numbers and their insignificance
for their lack of defensive armature. In some species
the male is adorned in the spring with bright pigment
—tred, black, blue, or milk-white. In some cases, too,
it has bony warts or horns on its head or body. Such
forms are known to the boys as horned dace.

Most interesting to the angler are the members of the
salmon and trout family (fig. 171), because they are
gamy, beautiful, excellent as food, and above all per-
nN
nN

FIRST LESSONS IN ZOOLOGY

haps, because they live in the swiftest and clearest
waters in the most charming forests. The salmon live
in the ocean most of their lives, but ascend the rivers
from the sea to deposit their eggs. The king salmon of
the Columbia goes up the great river more than a thou-
sand miles, taking the whole summer for it, and never
feeding while in fresh water. Besides the different kinds
of salmon the black-spotted or true trout, the charr or
red-spotted trout of various species, the whitefish, the

 

Fic. 171.—The rainbow-trout, Sa/mo irideus, (From specimen.)

grayling, and the famous ayu of Japan belong to this
family.

In the sea are multitudes of fish forms. The myriad
species of eels agree in having a long, flexible, snake-
like body, without ventral fins. Most of them live in the
sea, but the single genus of true eels which ascends the
rivers is exceedingly abundant and widely distributed.
Most eels are extremely voracious, but some of them
have mouths that would barely admit a pin-head. Cod-
fishes are creatures of little beauty but of great useful-
ness, swarming in arctic and subarctic seas. The her-
ring, soft and weak in body, are more numerous in indi-
viduals than any other fishes. The flounders, of many
kinds, lie flat on the sea bottom. They have the head so
twisted that the two eyes occur both together on the
FISHES, BATRACHIANS, AND REPTILES 213

uppermost side (fig. 172). The members of the great
mackerel tribe swim in the open sea, often in great
schools. Largest and swiftest of these is the swordfish,
in which the whole upper jaw is grown together to form
a long bony sword, a weapon of offense that can pierce
the wooden bottom of a boat.

Many of the ocean fishes are of strange form and ap-
pearance. The sea-horses (fig. 174) are odd fishes, cov-
ered with a bony shell, and with the head shaped like
that of a horse. They are little fishes, rarely a foot long,

 

Fic. 172.—-The winter flounder, Pseudopleuronectes americanus. (After
Goode. )

and cling by their curved tails to floating seaweed. The
porcupine fishes and swell fishes have the power of filling
the stomach with air, which they gulp from the surface.
They then escape from their pursuers by floating as a
round spiny ball on the surface. The flying fishes leap
out of the water, and sail for long distances through the
air like grasshoppers. They cannot flap their long pec-
toral fins, and do not truly fly, but strike the anal fin
with great force against the water in making a leap so
that they move swiftly, and thus escape their pursuers.
In its structure a flying fish differs little from a pike or
other ordinary fish.
214 FIRST LESSONS IN ZOOLOGY

The rays and skates are peculiar ocean fishes, which
lie at the bottom of shallow shore-waters. They feed on
crabs, molluscs, and bottom-fishes. The small common
skates, ‘‘ tobacco-boxes ’’ (fig. 174), about twenty inches

long, and the larger

’

‘«barn-door’’ skates are
numerous along the At-
lantic coast from Virginia
northward. Especially in-
teresting members of this
group, because of the pe-
culiar character of the in-
juries produced by them,
are the sting-rays and tor-
pedoes, or electric-rays.
The sting-rays have spines
near the base of the tail
which cause very painful
wounds. The torpedoes
have two large electrical
organs, one on each side
of the body, just behind
the head, with which they
can give a strong electric
shock. ‘*The discharge
from a large individual is
sufficient to temporarily
disable a man, and were

 

Fic. 173.—A_ sea-horse, //ppocampus

kellovt’, (This fish is eight inches
long; after Jordan and Snyder. ) these animals at all nu-
merous they would prove dangerous to bathers.’’ Very

different from the typical rays in external appearance are
the sawfishes, which belong to this group. The body
is elongate and shark-like, and has a long, saw-like
snout. This saw, which in large individuals may reach
aleneth of six feet and a breadth of twelve inches,
FISHES, BATRACHIANS, AND REPTILES 215

makes its owner formidable among the small sardines
and herring-like fishes on which it feeds. The sawfishes
live in tropical rivers, descending to the sea.

 

Fic. 174.—The common skate, Aaja erinacea. (From Kingsley.)

Baskett’s ‘‘ Story of the Fishes,’’ McCarthy’s ‘‘ Famil-
iar Fish,’’ and Jordan and Evermann’s ‘‘ Food and Game
Fishes of America ’’ are good books for elementary stu-
dents of fishes.

The batrachians.—We have made the acquaintance
of the most familiar batrachians in our study of the
life-history of the toad and frog (Chapter II). Other
familiar members of this class are the salamanders.
All batrachians breathe by means of gills for a longer
or shorter time after birth. But except in very few
cases these gills are lost and lungs developed so that
216 FIRST LESSONS IN ZOOLOGY

the adults cannot breathe under water. The toads
and frogs are closely related, and have about the same
life-history and habits, except that the fully-grown
toads live on land instead of in and about ponds. In
structure toads differ from frogs in having no teeth.
There are only a few toad species in North America,
but one of these is very abundant and widespread. It
appears in two or three varieties, the common toad of
the Southern States differing in several particulars from
that of the Northern. The toad is a familiar inhab-
itant of gardens, and does much good by feeding on
noxious insects. It is most active at twilight. Its eggs
are laid in a single line in the center of a long, slender,
gelatinous string or rope, which is nearly always tangled

 

Fic. 175.--The remora or cling fish, Remoropsis brachyplera, by means of
the curious sucker on top of the head this fish clings to sharks and is
thus carried swiftly for long distances. (After Goode. )

and wound round some water-plant or stick near the shore
on the bottom of a pond. The eggs are jet black, and
when freshly laid are nearly spherical. At the time of
the egg-laying the toads croak or call, making a sort of
whistling sound, and at the same time pronouncing deep
in the throat ‘‘bu-rr-r-r-r.’’ The toad does not open
its mouth when croaking, but expands a large sac or
resonator in its throat. The toad tadpoles are blacker
than those of frogs or salamanders, and undergo their
metamorphosis while of smaller size than those of frogs.
When they leave the water they travel for long distances,
hopping along so vigorously that in a few days they may
be as far as a mile from the pond where they were
FISHES, BATRACHIANS. AND REPTILES 217

hatched. They conceal themselves by day, but will
appear after a warm shower; this sudden appearance of
many small toads sometimes gives rise to the false notion
that they have fallen with the rain.

There are about a dozen species of frogs in the United
States. The largest of these, and indeed the largest of
all the frogs, is the well-known bullfrog, which reaches
a length (head to the posterior end of the body) of eight
inches. It is found in ponds and sluggish streams all
over the eastern United States and in the Mississippi
valley. It is greenish in color, with the head usually
bright pale-green. Its croaking is very deep and sono-
rous. The pickerel-frog, which is bright brown on the
back, with two rows of large, oblong, square blotches of
dark brown, is foundin the mountains of the eastern United
States. The little, pale, reddish-brown wood-frog, with
arms and legs barred above, is common in damp woods,
and is ‘‘an almost silent frog.’’ The peculiar frogs,
infrequently seen, known as the ‘‘spade-foots,’’ are
subterranean in habit, and usually live in dry fields, or
even arid plains and deserts. They pass through their
development and metamorphosis very rapidly, appearing
immediately after a rain, and laying their eggs in tempo-
rary pools. At this time they utter extraordinarily loud
and strange cries. Some frogs, in other parts of the
world, live in trees, and the eggs of one species are
deposited on the leaves of the trees, leaves which over-
hang the water being selected, so that the issuing young
may drop into it.

The true tree-frogs, or tree-toads, constitute a family
especially well represented in tropical America. They
have little disk- or pad-like swellings on the tips of their
toes, to enable them to hold firmly to the branches of the
trees in which they live. Some, like the swamp tree-
frog and the cricket-frog, are not arboreal in habit,
215 FIRST LESSONS IN ZOOLOGY

remaining almost always on the ground. The common
tree-frog of the Eastern States is green, gray, or brown
above, with irregular dark blotches, and yellow below.
It croaks or trills, especially at evening or in damp

 

ic. 176.—The tiger salamander. (From Jenkins and Kellogg.)

weather. Pickering’s trec-frog makes the ‘‘ first note of
spring’’ in the Eastern States. This is the one most
frequently heard in the autumn, too, but ‘‘ its voice is less
vivacious than in the spring, and its lonely pipe in dry
woodlands is always associated with goldenrods and asters
and falling Ieaves.’’ The tree-frogs of North America
lay their eggs in the water on some fixed object like an
aquatic plant, in smaller packets than those of the true
frogs, and not in strings as do the toads.

 

Fic. 177.-—The Western brown eft, or salamander, Diemyety/us torosus.
(From living specimen.) a os
Phe salamanders (figs. 176 and 177) are batrachians, with

the body not short and tailless as in the frogs and toads,
FISHES, BATRACHIANS, AND REPTILES 219

but elongate and slender and tailed. Their life-history is
like that of the frogs, although some salamanders which
live on land (they are to be found under logs and stones
in the woods) produce their young alive. To compare the
external structure of a salamander with that of a frog or
toad one of the tiger salamanders or one of the little tri-
tons or efts, common all over the country, should be used.
The little green triton or eft of the Eastern States, or
its larger brown-backed congener (fig. 177) of the Pacific
coast, is common in water, while another eft, the little
red-backed salamander, is common in the woods under
logs and stones.

The reptiles.—The class of reptiles includes the liz-
ards, snakes, tortoises, turtles, crocodiles, and alligators.
They are cold-blooded and breathe for their whole life
exclusively by means of lungs, the forms which live
in water coming to the surface to breathe. They are
covered with horny scales or plates, which with the en-
tire absence of gills after hatching readily distinguish
them from all the batrachians. While most reptiles live
on land, some inhabit fresh water and some the ocean.
As the young have the same habitat and general habits
as the adult, there is no such metamorphosis in their
life-history as is shown by the batrachians. The reptiles
are widespread geographically, occurring, however, in
greatest abundance in tropical regions, and being wholly
absent from the arctic zone. They are not capable of
such migrations as are accomplished by birds and many
mammals, but withstand severely hot or cold seasons by
passing into a state of suspended animation or seasonal
sleep or torpor.

The chief variations in body-form among the reptiles are
manifest when a turtle, lizard, and snake are compared.
In the turtles (fig. 178) the body is short, flattened, and
heavy, and provided always with four limbs, each termi-
220 FIRST LESSONS IN ZOOLOGY

nating in a five-toed foot; in the lizards the body is more
elongate, and with usually four legs, but sometimes with
two only, or even none at all; while in the snakes the
long, slender, cylindrical body is legless, or at most has
mere rudiments of the hinder limbs. With the reptiles,
locomotion is as often effected by the bending or serpen-

 

 

 

Fic, 178.—A sea-turtle, Che/one mydas, common in tropic oceans, (This
turtle is six feet long; drawn from a photograph by R. E. Snodgrass,
made on the Galapagos Islands, Pacific Ocean.)

tine movements of the trunk as by the use of the legs.
Among lizards and snakes the body is covered with
horny epidermal scales or plates, while among the turtles
and crocodiles there may be, in addition to the epidermal
plates, a real deposit of bone in the skin whereby the
effectiveness of the armor is increased. The epidermal
covering of snakes and lizards is periodically moulted,
or, as we say, the skinis shed. The bright colors and pat-
terns of snakes and of many lizards are due to the presence

and arrangement of pigment cells in the skin. Among
FISHES, BATRACHIANS, AND REPTILES 221

some reptiles, notably the chameleons, the colors and
markings can be quickly and radically changed by an au-
tomatic change in the tension of the skin.

Specimens of some pond or land turtle common in the
vicinity of the school should be obtained. The red-
bellied and yellow-bellied terrapins, or the painted or mud-
turtles are common over most of the United States. They
may be raked up from creek bottoms or fished for with

 

Fic. 179.—The giant land-tortoise of the Galapagos Islands, Zvstudo sp.
These tortoises reach a length of four feet. (Photograph from life by
Geo. Coleman from specimen brought to Stanford University by Snod-
grass and Heller.)

strong hook and line, using meat asa bait. They will

live through the winter, if kept in a cool place, without

food or special care of any kind. Observe their swimming
and diving, the retraction of head and limbs into the shell,
the use of the third eyelid (nictitating membrane), and
the swallowing of the air. Note the ‘‘shell,’’ consist-
ing of a dorsal plate, the carapace and ventral plate, plas-
tron, and the lateral uniting parts, the bridge. Almost
all the fresh-water and land turtles are carnivorous, but
few catch any very active prey. While some are strictly
FIRST LESSONS IN ZOOLOGY

i
N
N

aquatic others are as strictly terrestrial, never entering the
water. The eggs of all are oblong and are deposited in
hollows, sometimes covered in the sand. The newly
hatched young are usually circular in shape, and differ
in color and pattern from the adults.

The group of lizards (fig. 180) is a very large one,
about 1500 species being known in the world, but it
is represented in the United States by comparatively
few species. Specimens of some species of the com-

 

 

Fic. 180,—A lizard in the grass. (Photograph from life by Cherry
Kearton; permission of Cassell & Co.)

mon swift are obtainable almost anywhere in the United
States. They may be looked for in woods, along
fences, and especially on warm rocks. In certain
regions the glass-snake or joint-snake is common.
This lizard, popularly considered to be a snake, has
no external limbs, and its tail is so brittle, the vertebra
composing it being very fragile, that part of it may
break off at the slightest blow. In time a new tail is
regenerated. It lives in the central and northern part
of the United States, and burrows in dry places. In the
western part of the country horned toads are common,
about ten different specics being known. These are liz-
FISHES, BATRACHIANS, AND REPTILES 223

ards with shortened and depressed body and well-devel-
oped legs. The body is covered with protective spiny
protuberances, and in individual color and pattern re-

 

Fic. 181.—The blue-tailed skink, EAumeces skeltonianus. (From living
specimen, )

sembles closely the soil, rocks, and cactuses among
which the particular horned toad lives. All the spe-
cies of horned toads are viviparous, seven or eight
young being born alive at a time.

In New Mexico, Arizona, and northern Mexico the
only existing poisonous lizard, the Gila monster (fig. 182),

 

Fic. 182.—The Gila monster, Heloderma horridum, the only poisonous
lizard. (One-fourth natural size; photograph from life by J. O. Snyder.)

is found. This is a heavy, deep-black, orange-mottled
lizard about sixteen inches long. There is much variance
of belief among people regarding the Gila monster, but
recent experiments have proved the poisonous nature ot
the animal. The poison, which is secreted by the glands
in the lower jaw, flows along the grooved teeth into the
wound. A beautiful and interesting little lizard found in
the south is the green chameleon. Its body is about three
inches long, with a slender tail of about five or six inches.
The normal color of the chameleon is grass-green, but it
224 FIRST LESSONS IN ZOOLOGY

may ‘‘assume almost instantly shades varying from a
beautiful emerald to a dark and iridescent bronze color.”’

About 1000 living species of snakes are known. Usu-
ally they have the body regularly cylindrical, and without
distinct division into body-regions. Legs are wanting,
locomotion being effected by the help of the scales and
ribs. No snake can move forward on a perfectly smooth
surface, and no snake can leap. In some forms, such as

 

 

 

 

 

Fic. 183.—The yopher-snake, Pidvophis bellona. (Photograph from life by
J. O. Snyder, )

the pythons, external rudiments of the hind limbs are
present, but do not aid in locomotion. The mouth is
large and distensible, so that prey of considerably greater
size than the normal diameter of the snake’s body is fre-
quently swallowed whole. The sense of taste is very
little if at all developed, as the food is swallowed without
mastication. The tongue, which is protrusible, and usu-
ally red or blue-black, serves as a special organ of touch.
Fearing is poor, the cars being very little developed. The
sense of sight is also probably not at all keen. Snakes
rely chiefly on the sense of smell for finding their prey
and their mates. The colors of snakes are often brilliant,
FISHES, BATRACHIANS, AND REPTILES 225

and in many cases serve to produce an effective protective
resemblance by harmonizing with the usual surroundings
of the animal. The food of snakes consists almost ex-
clusively of other animals, which are caught alive. Some
of the poisonous snakes kill their prey before swallowing
it, as do some of the constrictors. While most snakes

 

 

 

 

 

Fic. 184.—A garter-snake, Thammnophis parietalis, (Photograph from
life by J. O, Snyder.)

live on the ground, some are semi-arboreal and others
spend part or all of their time in the water. Cold-
region snakes spend the winter in a state of suspended
animation ; in the tropics, on the contrary, the hottest part
of the year is spent by some species in a similar ‘‘sleep.’’

Among the commonest members of this group are the
garter-snakes (fig. 184), always striped, and not more than
three feet long. The most widespread species is rather dully
colored, with three series of small dark spots along each
side. The common water-snake is brownish, with back
and sides each with a series of about eighty large, square,
dark blotches alternating with each other. It feeds on
fishes and frogs, and, although unpleasant and ill-tem-
pered, is harmless. One of the prettiest and most gentle
of snakes is the familiar little green-snake, common in the
East and South in moist meadows and in bushes near the
water. It feeds on insects, and can be easily kept alive
226 FIRST LESSONS IN ZOOLOGY

in confinement. A familiar larger snake is the black-
snake, or ‘¢blue-racer,’’ lustrous pitch-black, general
color greenish below, and with white throat. It is ‘ often
found in the neighborhood of water, and is particularly
partial to the thickets of alders, where it can hunt for
toads, mice, and birds, and, being an excellent climber,
it is often seen among the branches of small trees and
bushes, hunting for young birds in the nest.’’ The chain-
snake of the Southeast and the king-snake (fig. 185) of the
Central States are beautiful, lustrous, black-and-yellow-

 

 

 

 

 

Fic 185,.—A king-snake, Lampropeltis boyli, (Photograph from life by
J. O. Snyder.)

spotted snakes, which feed not only on lizards, salaman-
ders, small birds, and mice, but also on other snakes.
The king-snake should be protected in regions infested by
‘‘rattlers.’’ The spreading-adder, or blowing-viper, a
common snake in the Eastern States, brownish or red-
dish, with dark dorsal and lateral blotches, depresses and
expands the head when angry, hissing and threatening.
Despite the popular belief in its poisonous nature this
ugly reptile is quite harmless. It specially infests dry
and sandy places.

With the exception of the coral- or bead-snake, a rather
small, jet-black snake, with seventeen broad, yellow-
bordered crimson rings, found in the Southern States, the
FISHES, BATRACHIANS, AND REPTILES 227

only poisonous snakes of the United States are the rattle-
snakes and their immediate relatives, the copperhead and
water-moccasin. These snakes all have a large triangular
head, and in the rattlesnakes the posterior tip of the body
is provided with a
‘‘rattle,’’ composed
of a series of partly
overlapping, thin,
horny capsules, or
cones, of shape as

shown in fig. 186. —-+n77

These horny pieces WAG

are simply the some- J

what modified, succes- ee IE ZI

sively formed epider- Fic. 186.—The rattles of the rattlesnake;
mal coverings of the _ the lower figure shows a longitudinal sec-

tip of the body, which a

instead of being entirely moulted as the rest of the skin is,
are, because of their peculiar shape, loosely attached to one
another, and by the basal one to the body of the snake.
The number of rattles does not correspond to the snake’s
years for several reasons, partly because more than one
rattle can be added in a year, and especially because
rattles are easily and often broken off. As many as
thirty rattles have been found on one snake. There are
two species of ground-rattlesnakes, or massasaugas, in
the United States, and ten species of the true rattlesnakes.
The center of distribution of the rattlesnakes is the dry
tablelands of the Southwest in New Mexico, Arizona, and
Texas. But there are few localities in the United States
outside the high mountains in which ‘‘rattlers’’ do not
occur, or did not occur before they were exterminated by
man. The copperhead is light chestnut in color, with
inverted Y-shaped darker blotches on the sides, and
seldom exceeds three feet in length. It occurs in the

 
228 FIRST LESSONS IN ZOOLOGY

Eastern and Middle United States, from Pennsylvania
and Nebraska southward. It is a vicious and dangerous
snake, striking without warning. The water-moccasin is
dark chestnut-brown, with darker markings. The head
is purplish-black above. It is found along the Atlantic
and Gulf coasts from North Carolina to Mexico, extend-
ing also some distance up the Mississippi valley. It is
distinctively a water-snake, being found in damp, swampy
places or actually in water. It reaches a length of over
four feet, and is a very venomous snake, striking on the
slightest provocation. The common, harmless water-
snake is often called water-moccasin in the Southern
States, being popularly confounded with this most dan-
gerous of our serpents. The
poison of all of these snakes
is a rather yellowish, trans-
parent, sticky fluid, secreted
by glands in the head, from
which it flows through the
hollow maxillary fangs. The
character and position of
the fangs are shown in fig.
Fic, 187.—Dissection of head of rat- 187. Remedial measures for

tlesnake; /, poison-fangs; /, poison- the bite of poisonous snakes

oss are, first, to stop, if possible,
the flow of blood from the wound to the heart by com-
pressing the veins between the wound and _ the heart;
then (if the lips are unbroken) to suck the poison from the
wound; next to introduce by hypodermic injection per-
manganate of potash, bichloride of mercury, or chromic
acid into the wound; and finally, perhaps, to take some
strong stimulant, as brandy or whiskey.

 

The crocodiles and alligators are reptiles familiar by
name and appearance, though seen in nature only by the
inhabitants or visitors in tropical and semi-tropical lands.
FISHES, BATRACHIANS, AND REPTILES 229

In the United States there are two species of these great
reptiles: the American crocodile, living in the West
Indies and South America, and occasionally found in
Florida; and the American alligator, common in the
morasses and stagnant pools of the Southern States. The
alligator differs from the crocodiles in having a broader
snout. It is rarely more than twelve feet long. The
best-known crocodile is the Nile crocodile, which is not
limited to the Nile, but is found throughout Africa. In
the Ganges of India is found another member of this
group of reptiles, called the gavial. It is among the
largest of the order, reaching a length of twenty feet.
The crocodiles, alligators, and gavials comprise not more
than a score of species altogether, but because of their
wide distribution, great size, and carnivorous habits they
are among the most conspicuous of the larger living ani-
mals. They live mostly in the water, going on land to
sun themselves or to lay their eggs. They move very
quickly and swiftly in water, but are awkward on land.
Fish, aquatic mammals, and other animals which occa-
sionally visit the water are their prey. The gavial and
Nile crocodile are both known to attack and devour
human beings, and these species annually cause a consid-
erable loss of life. But few such fatalities, however, are
accredited to the American alligator.
CHAPTER XV

BIRDS

The English sparrow.—We have already studied
(Chapter V) the external parts of a bird, the English
sparrow, and have thus become acquainted with the
superficial characteristics of a bird’s body. The life-his-
tory and habits of the sparrow can also be readily ob-
served, and will serve as an introduction to the study of
the life-history of more interesting birds.

The English sparrow was first introduced into the
United States in 1850, and since that time has rapidly
populated most of the cities and towns of the country.
On account of its extreme adaptability to surroundings,
its omnivorous food-habits, and its fecundity, it survives
where other birds would die out. It also crowds out and
has caused the disappearance or death of other birds more
attractive and more useful. The sparrow annually rears
five or six broods of young, laying from six to ten eggs
at each sitting. Unmolested a single pair would multi-
ply to a most astonishing number. It has, however,
many enemies, most common among them perhaps being
the ‘«small boy,’’ but birds and mammals play the chief
part in the destruction. The smaller hawks prey upon
it, and rats and mice destroy great numbers of its young
and of its eggs whenever the nests can be reached. The
sparrow is omnivorous and when driven to it is a loath-
some scavenger, though at other times its tastes are for
dainty fruits. Its senses of perception are of the keenest;

230
BIRDS 231

it can determine friend or foe at long range. The nest-
ing habits are simple, the nests being roughly made of
any sort of twigs and stems mixed with hair and feathers
and placed in cornices or trees. A maple-tree in a small

 

Fic, 188.—Cardinal grosbeak, or redbird (Cardinalis cardinalis), (One-
half natural size; from life.)

Missouri town contained at one time thirty-seven of these
nests.

The beginning study of birds.—In Chapter III are
given directions for the observation of the nesting habits
of birds. Such observations constitute probably the best
232 FIRST LESSONS IN ZOOLOGY

kind of beginning in bird-study, but certain other phases
will suggest themselves at once to the student. One
will need to recognize the different common kinds of
birds and to know their names; also to learn the facts
about the annual history of each familiar one, finding
out if it lives in the neighborhood of the school all the
year, or in summer alone or winter alone, or is only a
bird of passage, a migrant, appearing in the spring and

 

 

Fic, 189.—The nest and eves of the black pheebe, Savernts nigricans,
(Photograph by J. O. Snyder.)

autumn for a brief period cach year. There will be inter-
esting observations to be made on the food habits of each
kind, the getting acquainted with its calls and song, its
manner of flight, and the special details of its nest-making
and care of young. In the following paragraphs are given
suggestions for the guidance of the student in all of these
different phases of bird-study. So many books about bird-
life have been published recently that no trouble should
be experienced in finding such euides to further study
along any or all of the lines pointed out in this chapter.
BIRDS 233

Classification and identification.— The class of birds,
Aves, is divided into various orders, of which seventeen
are represented in North America. There are eight
hundred (approximately) different species of North Amer-
ican birds, but in any one locality not more than about
a third of these species can be found, and of these only
comparatively few are common or numerous. So that
to learn the common birds of a single locality is not a

 

 

 

 

 

Fic. 190.—Western chipping sparrow, Sfizel/a socialis avizone, (Photo-
graph from life by Eliz, and Jos. Grinnell.)

large matter; it means getting acquainted with perhaps
fifty or sixty different kinds. As birds can usually
be readily identified by their size and shape, and the color
pattern of their plumage, this class is especially well
adapted for the beginning study of systematic zoology,
which concerns the identification and classification of
species.

To identify the various species of birds in the locality
of the school it will be necessary to have some book
234 FIRST LESSONS IN ZOOLOGY

giving the descriptions of all or most of the species of the
region, with tables and keys for tracing out the different
forms. The best general manual is Coues’ ‘‘ Key to the
Birds of North America,’’ which includes not only keys
for tracing and descriptions of all the known species of
birds on this continent, but also accounts of the distribu-
tion, of the nesting and eggs, and of the plumage of the
young birds, besides a thorough introduction to the anat-

 

 

 

 

 

Tic. 191,—Russet-backed thrush, Zardus ustu/atus, (Photograph from
life by Eliz. and Jos Grinnell.)

omy and physiology of birds, and directions for collecting
and preserving them.  Jordan’s ‘* Manual of Verte-
brates ’’ gives keys and compact but clear descriptions of
the birds found cast of the Missouri River; Chapman's
“Handbook of the Birds of Eastern North America,’’
and Florence Bailey's ‘* Birds of the Western States,’’ are
excclent. To use these manuals effectively it is neces-
sary to have the bird’s body in hand; and that means
BIRDS 235

usually death for the bird. Recently there have been
published several bird-keys which attempt to make it pos-
sible to determine species, the commoner ones at any rate,
by examination of the living bird in the trees by means
of an opera-glass, or often with the unaided eye. Chap-
man’s ‘‘ Bird-Life ’’ is an example of the better sort of
these books. From this the following is quoted:

 

 

 

 

Fic. 192.—Western robin, Aferiula migratoria propingua, (Photograph
from life by Eliz. and Jos. Grinnell.)

‘« We come now to the practical question of identifica-
tion. How are we to find birds, and having found them,
how are we to learn their names ?

‘““From April to August there is probably not a min-
ute of the day when in a favorable locality one cannot
see or hear birds; and there is not a day in the year when
at least some birds cannot be found. In the beginning,

 
nN
ww
a

FIRST LESSONS IN ZOOLOGY

therefore, the question of finding them is simply a matter
of looking and listening. Later will come the delightful
hunts for certain rarer species whose acquaintance we
may make only through a knowledge of their haunts and
habits.

‘« Having found your bird, there is one thing absolutely
necessary to its identification; you must see it definitely,

 

 

 

  

 

 

Fic. 193.—Sickle-billed thrasher, //arporhynchus redivivus. (Photograph
from life by Eliz. and Jos. Grinnell.)

Do not describe a bird to an ornithologist as ‘brown,
with white spots on its wings,’ and then expect him to
tell you what it is. Would you think of trying to identify
BIRDS 237

flowers of which you caught only a glimpse from a car-

You
did not see them definitely,
and at best you can only
carry their image in your
mind until you have oppor-
tunity to see them in detail.

‘So it is with birds.
Do not be discouraged if
the books fail to show you
the brown bird with white
spots on its wings. Prob-
ably it exists only through
your hasty observation.

‘© Arm yourself with a
field- or opera-glass, there-
fore, which you
will be badly handicapped,
and look your bird over
with enough care to geta
general idea of its size, form
—particularly the form of
the bill—color, and mark-
Then—and I cannot
emphasize this too strongly

window in passing?

without

ings.

 

—put what you have seen
into your notebook at once.
For, as I have elsewhere
said, ‘not only do our
memories sometimes de-
ceive us, but we really see
nothing with exactness until
we attempt to describe it.’

‘Tt is true that all the

 

Fic,

   

"bea
194.—Nest and eggs of ruby-
throat humming-bird,  Zrochzlus
colubris, seen from above. in apple-
tree. (Photograph by E. G, Tabor;
permission of Macmillan Co.)

birds will not pose before your glasses long enough for
238 FIRST LESSONS IN ZOOLOGY

you to examine them at your leisure, but many of them
will, and in following the others you will have all the
excitement of the chase. Who knows what rare species
the stranger may prove to be!

‘““From your description, and what added notes on
voice and actions you may obtain, the field-key and illus-

 

Fic. 195.—Puffins. (After photograph from life by C. Kearton.)

trations on the succeeding pages should make identifica-
tion a simple matter.’’

Birds and the seasons.—In trying to become ac-
quainted with the birds of a locality it must be borne in
mind that the bird-fauna of any region varies with the
season. Some birds live in it all the year through; these
are called residents. Some spend only the summer or
breeding season in the locality, coming up from the
South in spring and flying back in autumn; these are
summer residents. Some spend only the winter in the
locality, coming down from the severer North at the
beginning of winter, and going back with the coming of
spring; these are winter residents. Some are to be found
in the locality only in spring and autumn, as they are
migrating north and south between their tropical winter
quarters and their northern summer or breeding home;
these are migrants. And, finally, an occasional repre-
sentative of certain bird species, whose normal range
does not include the given locality at all, will appear now
BIRDS 239

and then, blown aside from its regular path of migration,
or otherwise astray; these are visitants. As to the rela-
tive importance, numerically, of these various categories
among the birds which may be found in a certain region,
and thus form its bird-fauna, we may illustrate by refer-
ence to a definite region. Of the 351 species of birds
which have been found in the State of Kansas (a region
without distinct natural boundaries, and fairly represen-
tative of any Mississippi valley region of similar extent),
51 are all-year residents, 125 are summer residents, 36
are winter residents, 104 are migrants, and 35 are rare
visitants.

The all-year residents and the summer residents, com-
prising about one-half of the species to be found in a
locality are the only ones which breed there, and which
thus present opportunity for observations on their nest-
building habits and care of the young. Numerous sug-
gestive questions present themselves in connection with
breeding in addition to the simpler ones already pro-
pounded in Chapter III. Why is it that some species
nest early and some late? Can the character of the food
of the young have anything to do with this? Ifso, how?
Does the condition of the particular trees, bushes or other
favorite sites for nests help determine the nesting time ?
Why should some birds raise but one brood a year, and
others two or even three? Does the fact that a bird is
an all-year resident or only a summer resident have any
influence in determining its nesting time and the number
of broods it rears? Compare the habits of the various
breeding species of the locality, and find out if the
summer residents have any breeding habits in common
as distinguished from the all-year residents.

Observe the behavior of the birds in courting time.
Do the males have ‘‘ singing contests,’’ as is sometimes
reported? Do they fight with each other? Do the males
240 FIRST LESSONS IN ZOOLOGY

or females show any differences, at this time, from their
more usual plumage ? After mating which bird selects

the nesting site ?

Are old nesting sites preferred to new
ones? If two broods are reared is a new nest built ?
What are the principal causes of mortality among the
eggs and young
during the breeding
season 2? What in-
stincts or habits of
the parents have
direct reference to
these dangerous
conditions ? What
means of protecting
the nest are resorted
to? What is the
behavior of the par-
entstowardsenemies
of the young ?

As explained in
Chapter NXI, the
geographical distri-
bution of animals is
a subject of much
importance, and
offers good oppor-

 

tunities in its more
local features for
Fic = 196.—Razorbill auk and egg. (After student. field-work.
photograph from life by C. Kearton.) <3

The field-study of
the birds of a given locality will comprise much observation
bearing directly on zoogeography, or the distribution of
animals. Certain birds will be found to be limited to cer-
tain parts of even a small region; the swimmers will be
found in ponds and streams, and the long-legg¢ed shore-

oc
BIRDS 241

birds on the pond- or stream-banks, or in the marshes
and wet meadows, although a few, like the upland-plover,
curlews, and godwits are common on the dry upland pas-
tures. Distinguish the ground-birds from the birds of the
shrubs and hedge-rows, and these again from the strictly
forest-birds. Find the special haunts of swallows and king-
fishers. Which are the shy birds driven constantly deeper
into the wild places, or being exterminated by the advance
of man? Which birds do not retreat, but even find an
advantage in man’s seizure of the land, obtaining food
from his fields and gardens ?

Make a map on large scale of the locality of the school,
showing on it the topographic features of the region, such
as streams, ponds, marshes, hills, woods, springs, wild
pastures, etc., also roads and paths, and such landmarks
as schoolhouses, country churches, etc. On this map
indicate the local distribution of the birds, as determined
by the data gradually gathered; mark favorite nesting-
places of various species, roosting-places of crows and
blackbirds, feeding-places, and bathing- and drinking-
places of certain kinds, the exact spots of finding rare
visitants, rare nests, etc.

As already mentioned, many of the birds of a locality
are ‘‘migrants,’’ that is, they breed farther north, but
spend the winter in more southern latitudes. These
migrants pass through the locality twice each year, going
North in the spring and South in the autumn. They are
much more likely to be observed during the spring migra-
tion than in the fall, as the flight South is usually more
hurried. The observation of the migration of birds is very
interesting, and much can be done by beginning students.
Notes should be made recording the first time each spring
a migrating species is seen, the time when it is most
abundant, and the last time it is seen the same spring.
Similar records should be made showing the movements
242 FIRST LESSONS IN ZOOLOGY

of the birds in the fall. A series of such records, covering
a few years, will show which are the carliest to appear,
which the later, and which the last. Such records of
appearance and disappearance should also be kept for the
summer residents, those birds that come from the South
in the spring, breed in the locality, and then depart for

 

 

Fic. 197.—Young barn-owls. (Photograph by Geo. Towne ; permission of
The Condor.)

the South again in the autumn. Notes on the kinds of
days, as stormy, clear, cold, warm, etc., on which the
migration scems to be most active; on the greater prev-
alence of migratory flights by day or by night; on the
height from the carth at which the migrants fly, ete., are
all worth while. For an excellent simple account of
migration see Chapman’s ‘‘ Bird-Life,’’ Chapter TV. A

book about migration, and one giving the records for
BIRDS 243

many species at many points in the Mississippi Valley, is
Cooke’s ‘‘ Bird Migration in the Mississippi Valley.’’

It must also be kept in mind in using bird-keys and de-
scriptions to determine species that the descriptions and

 

Fic. 198.—Nest of buff-breasted flycatcher, Empidonax fulvifrons pygmaeus,
on cone of pine-tree. (Photograph by R. D. Lusk; permission of
The Condor.)

keys refer to adult birds, and in ordinary plumage. Among
numerous birds the young of the year, old enough to fly
and as large as the adults, still differ considerably in plum-
age from the latter; males differ from females, and finally
244 FIRST LESSONS IN ZOOLOGY

both males and females may change their plumage (hence
color and markings) with the season. The seasonal
changes of plumage accomplished by moulting may be
marked or hardly noticeable. ‘‘ All birds get new suits
at least once a year, changing in the fall. Some change
in the spring also, either partially or wholly, while others
have as many as three changes—perhaps, to a slight ex-
tent, afew more. . . . It is claimed by some that now
all new colors are acquired by moult, and by others that
in some instances (young hawks) an infusion or loss, as
the case may be, of pigment takes place as the feather
forms, and continues so long as it grows.’’

There is much lack and uncertainty of knowledge con-
cerning the moulting and change of plumage by birds,
and careful observations by bird-students should be made
on the subject.

The uses of colors and patterns in animals are dis-
cussed in Chapter XVIII. For accounts of the plumage
and color of birds see Chapter HI in Chapman’s ‘ Bird-
Life,’’ and Chapters VIII and IX in Baskett’s “ Story of
the Birds.’’

Structure and habit.—In connection with learning the
different kinds of birds in a locality, observations should
be made, and notes of them recorded, on their habits,
and on their external structure and its relation to the hab-
its of the bird. The interesting adaptation of structure to
special use is particularly well shown in the varying char-
acter of the bill and feet-of birds. The various feeding
habits and uses of the feet of different birds are readily
observed, and the accompanying modification of bills and
fect can be readily seen in birds either freshly killed or
preserved as ‘‘ bird-skins.’’ Such skins may be made as
directed on p. 338, or may be bought cheaply of taxi-
dermists. A set of such skins, properly named, will be of

 

great help in studying birds, and should be in the high-
BIRDS 245

school collection. In some cases the general structure of
feet and bills may be seen in the live birds by the use of
an opera-glass. The characters of bills and feet are much
used in the classification of birds, so that any knowledge
of them gained primarily in the study of adaptations
will have a secondary use in classification work.

 

 

Fic, 199.—Ostriches on ostrich-farm at Pasadena, California. (Photograph
from life.)

Note the foot of the robin, bluebird, catbird, wren,
warbler, and other passerine or perching birds. It has
three unwebbed toes in front and along hind toe per-
fectly opposable to the middle front one. This is the
perching foot. Note the so-called zygodactyl foot of the
240 FIRST LESSONS IN ZOOLOGY

woodpecker, with two toes projecting in front and partly
yoked together, and two similarly yoked projecting be-
hind. Note the webbed swimming-foot of the aquatic
birds; note the different degrees of webbing, from the
totipalmate, where all four toes are completely webbed,
palmate, where the three front toes only are bound to-
gether but the web runs out to the claws, to the semi-
palmate, where the web runs out only about half-way.

 

 

 

 

Fic. 200,—Young ostriches just from egg, at ostrich-farm at Pasadena,
California, (Photograph from life.)

 

Note the lobate foot of the coots and phalaropes. Note
the long, slender, wading legs of the sandpipers, snipe,
and other shore-birds; the short, heavy, strong leg of the
divers; the small, weak leg of the swifts and humming-
birds, almost always onthe wing; the stout, heavily nailed
foot of the scratchers, as the hens, grouse, and turkeys ;
and the strong, grasping talons, with their sharp, long,
curving nails, of the hawks and owls, and other birds of
prey. In all these cases the fitness of the structure of
the foot to the special habits of the bird is apparent.
BIRDS 247

Similarly the shape and structural character of the bill
should be noted, as related to its use, this being chiefly
concerned of course with the feeding habits. Note the
strong, hooked, and dentate bill of the birds of prey; they

 

 

 

 

‘ S ‘ ‘44 eS j
Fic. 201.—The yellowhammer, Colafles auratus. (Photograph by
W. E. Carlin; permission of G, O. Shields.)

tear their prey. Note the long, slender, sensitive bill of
the sandpipers; they probe the wet sand for worms. Note
the short, weak bill and wide mouth of the night-hawk
and whippoorwill, and of the swifts and swallows; they
catch insects in this wide mouth while on the wing. Note
248 FIRST LESSONS IN ZOOLOGY

the flat, lamellate bill of the ducks; they scoop up mud
and water and strain their food from it. Note the firm,
chisel-like bill (fig. 201) of the woodpeckers ; they bore
into hard wood for insects. | Note the peculiarly crossed
mandibles of the cross-bills; they tear open pine cones
for seeds. Note the long, sharp, slender bill of the hum-

 

te 1
Fic. 202,—Screech-owl, A/egascops asio, (Photograph by A. L. Princeton;
permission of Macmillan Co.)
ming-birds; they get insects from the bottom of flower-
cups. Note the bill and foot of any bird you examine,
and see if you can recognize their special adaptation to
the habits of the bird.

The most casual observation of birds reveals differences
in the flight of different kinds so characteristic and dis-
tinctive as to give much aid in determining the identity
of birds in nature. Note the flight of the woodpeckers;
it identifies them unmistakably in the air. Note the
BIRDS 249

rapid beating of the wings of quail and grouse; also of
wild ducks; the slow, heavy, flapping of the larger hawks
and owls, and of the crows; and the splendid soaring of
the turkey-buzzard and of the gulls. This soaring has
been the subject of much observation and study, but is

 

 

 

 

+

Fic. 203,—Gulls soaring. (Photograph by Otto von Bargen, on San
Francisco Bay; permission of Camera Craft.)

still imperfectly understood. The soaring bird evidently
takes advantage of horizontal air-currents, and some
observers maintain that upward currents also must be
present. The principal hopes for the invention of a suc-
cessful flying-machine rest on the power of soaring
possessed by birds. The speed of flight of some birds
250 FIRST LESSONS IN ZOOLOGY

is enormous, the passenger-pigeon having been estimated
to attain a speed of one hundred miles an hour. The
long distances covered in a single continuous flight by
certain birds are also extraordinary, as is also the total
distance covered by some of the migrants. The differ-
ences in the structural character of the wings should be
noted in connection with the observation of the differ-
ences in flight habit.

The tongues and tails of birds are two other structures
the modifications and special uses of which may be readily
observed and studied. Note the structure and special use
of the tongue and tail (fig. 201) of the woodpeckers; note
the tongue of the humming-bird; the tail of the grackles.

Feeding habits, economics, and protection of birds.—
The feeding habits of birds are not only interesting, but
their determination decides the economic relation of birds
to man, that is, whether a particular bird species is harm-
ful or beneficial to man. Casual observation shows that
birds eat worms, grains, seeds, fruits, insects. A single
species often is both fruit-eating and insect-eating. Do
fruits or do insects compose the chief food-supply of the
species? To determine this more than casual observa-
tion is necessary. The birds must be watched when
feeding at different seasons. The most effective way of
determining the kind of food which the bird takes is to
examine the stomach of many individuals taken at vari-
ous times and localities. Much work of this kind has
been done, especially by investigators connected with
the Division of Biological Survey of the United States
Department of Agriculture, and pamphlets giving the
results of these investigations can be had from the Divi-
sion. It has been distinctly shown that a great majority
of birds are chiefly beneficial to man by eating noxious
insects and the seeds of weeds. Most birds commonly
reputed to be harmful, and for that reason shot by farm-
BIRDS 251

ers and fruit-growers, have been proved to do much more
good than harm. Some few birds have been proved to
be, on the whole, harmful. An investigation of the food
habits of the crow, a bird of ill-repute among farmers,
based on an examination of 909 stomachs, shows that
about 29 per cent of the food for the year consists of

 

Fic. 204.—Horned larks, Ofocoris alpestris, and snowflakes, Plectrophenax
nivalis. (Photograph from life by H. W. Menke; permission of
Macmillan Co.)

grain, of which corn constitutes something more than
21 per cent, the greatest quantity being eaten in the
three winter months. Ali of this must be either waste
grain picked up in fields and roads, or corn stolen from
cribs and shocks. May, the month of sprouting corn,
shows a slight increase over the other spring and summer
months. On the other hand, the loss of grain is offset by
the destruction of insects. These constitute more than
252 FIRST LESSONS IN ZOOLOGY

23 per cent of the crow’s yearly diet, and the larger part
of them are noxious. The remainder of the crow’s food
consists of wild fruit, seeds, and various animal substances
which may on the whole be considered neutral.

The slaughter of birds for millinery purposes has become
so fearful and apparent in recent years that a strong move-
ment for their protection has been inaugurated. Rapa-
cious egg-collecting, legislation against birds wrongly
thought to be harmful to grains and fruit, and the selfish
wholesale killing of birds by professional and amateur
hunters, help in the work of destruction. Apart from the
brutality of such slaughter, and the extermination of the
most beautiful and enjoyable of our animal companions,
this destruction works strongly against our material in-
terests. Birds are the natural enemies of insect pests, and
the destroying of the birds means the rapid increase and
spread, and the enhanced destructive power of the pests.
It is asserted by investigators that during the past fifteen
years the number of our common song-birds has been
reduced to one-fourth. At the present rate, says one
author, extermination of many species will occur during
the lives of most of us. Already the passenger-pigeon
and Carolina paroquet, only a few years ago abundant,
are practically exterminated. Protect the birds!
CHAPTER XVI
MAMMALS

The mammals constitute the highest group of animals,
including man, the monkeys and apes, the bird-like bats
and fish-like seals and whales, and all the various beasts we
commonly call quadrupeds; altogether about 2,500 known
species. They are found in all parts of the world except
on a few small South Sea islands. The name mammals
is derived from the mammary or milk glands which enable
the mothers to suckle their young. In size mammals
range from the tiny pigmy shrew and harvest-mouse
which can climb a stem of wheat, to the great sulphur-
bottom whale of the Pacific Ocean, that attains a length
of a hundred feet and a weight of many tons. Mammals
differ from fishes and batrachians and agree with reptiles
and birds in never having external gills; they differ from
reptiles and agree with birds in being warm-blooded and
in having a heart with two distinct ventricles and a com-
plete double circulation; finally, they differ from both rep-
tiles and birds in having the skin more or less clothed
with hair, the lungs freely suspended in a thoracic cavity
separated from the abdominal by a muscular partition, the
diaphragm, and in the possession by the females of mam-
mary glands. In economic uses to man mammals are the
most important of all animals. They furnish a great por-
tion of the animal food of many human races, likewise a
large amount of their clothing. Horses, asses, oxen,
camels, reindeer, elephants, and llamas are beasts of burden

253
254 FIRST LESSONS IN ZOOLOGY

and draught; swine, sheep, cattle, and goats furnish flesh,
and the two latter milk, for food; the wool of sheep, the
furs of the carnivores, and the leather of cattle, horses,
and others arc used for clothing, while the bones and
horns of various mammals serve many useful purposes.

 

 

A a,

 

 

 

Pic. 205.—Chipmunk. (Permission of Camera Craft.)

The house-mouse; an example.—Specimens of the
house-mouse should be obtained by trapping, and its ex-
ternal structure compared with that of the frog and sparrow.
The mouse, unlike the other vertebrates so far studied, is
thickly covered with hair all over its body except on the tip
MAMMALS 255

of the nose and the soles of the feet. Where are the
nostrils placed ? What are the large leaf-like expansions,
called pinnz, situated just back of the eyes? Pull open
the mouth and note the large incisor teeth on the upper
and lower jaws. Cut one corner of the mouth back and
observe the large flat-topped molar teeth on both jaws.
How does the attachment of the large fleshy tongue differ
from the condition in the toad? The toad’s tongue is for
snapping up insects, whereas in the mouse this organ
serves to move food about in the mouth. On the tongue
are numerous small taste-papilla. Notice the long hairs,
‘« feelers,’’ on each side of the nose. Note the similarity
between the front paws and our own hands; each has
four fingers, with a small rudimentary thumb on the inner
side of the paw. How does the hind foot of the mouse
differ from the foot of man? Posteriorly the body is
terminated by a long tail.

The house-mouse is not a native of North America,
but was introduced from Europe, to which, in turn,
it came from Asia, its original habitat. The mouse
came to this country in the vessels of early explorers.
Similarly the brown and black rats, now so abundant all
over North America, and members of the saine genus as
the mouse, were introduced from Europe. Accompany-
ing man in his travels the mouse has spread from Asia
until it is now to be found over the whole world.

The habits of mice are well known, their fondness for
living in our homes and outbuildings making them familiar
acquaintances. Their food is varied; they seem to thrive
best, however, on a vegetable diet. Grains and nuts are
favorite foods. The house-cat is their greatest enemy,
but man takes advantage of their instinct to go into holes
by constructing traps with funnel or tunnel entrances,
which, baited with cheese or other favorite food, are
fatally attractive. In climbing, mice are aided by the
256 FIRST LESSONS IN ZOOLOGY

tail. Their strong hind legs enable them to stand erect.,
and even to take several steps in this posture. They
can swim readily, although naturally they rarely take to
water. Their special senses are keen, the senses of hear-
ing and taste being unusually well developed. Their
‘«singing,’’ which has been the subject of much discussion,
seems to be actually a voluntary and normal performance,
which, however, hardly deserves to be called singing, but
rather a slightly varied peeping or whistling.

The mouse is a prolific mammal, producing from four
to six times a year broods of from four to eight young.
A cozy nest of straw, bits of paper, feathers, wool, or
other soft materials is made, and in this the young are
born. The newly born mice are very small and are
blind and helpless. They are odd little creatures, being
naked and almost transparent. They grow rapidly,
being covered with hair in a week, although not opening
their eyes for about two weeks. A day or two after
their eyes are open they begin to leave the nest, and
hunt for food for themselves.

Classification.—The mammals of North America rep-
resent eight orders. Three additional orders, namely, the
Monotremata, including the extraordinary duckbills of
Australia, the Edentata, including the sloths, armadillos
and ant-eaters found in tropical regions, and the Sirenia,
including the marine manatees and dugongs are not rep-
resented (except by a single manatee) in North America.
In the following paragraphs some of the more familiar
mammals representing each of the eight orders repre-
sented in North America are referred to.

The opossums and kangaroos (Marsupialia).-—The
opossum (Ledelphys virginiana) is the only North Amer-
ican representative of the order Marsupialia, the other
members of which are limited exclusively to Australia
and certain neighboring islands. The kangaroos are the
MAMMALS 257

 

 

 

 

lic. 206.—A group of Rocky Mountain sheep, or ‘big horns,” Ovzs
canadensts, including males, females, and young. (Photograph by E.
Willis from specimens mounted by Prof. L, L. Dyche, University of
Kansas.)
258 FIRST LESSONS IN ZOOLOGY

best known of the foreign marsupials. The members of
this order are characterized by the birth of the young
while very small and incompletely developed, and the
transference of the young to an external pouch, the mar-
supium, in which they are carried for a longer or shorter
time. The opossum lives in trees, is about the size of a
common cat, and has a dirty-yellowish woolly fur. Its
tail is long and scaly, like a rat’s. Its food consists
chiefly of insects, although small reptiles, birds, and bird’s
eggs are eaten. When ready to bear young the opossum
makes a nest of dried grass in the hollow of a tree, and
produces about thirteen very small (half an inch long)
helpless creatures. These are then placed by the mother
in her pouch, where each clings toa teat. Here they re-
main until two months or more after birth. Probably all
the North American opossums, found from New York to
California, and especially common in the Southern States,
belong to a single species, but there is much variety
among the individuals.

The rodents or gnawers (Glires).—The rabbits, por-
cupines, gophers, chipmunks, beavers, squirrels, and rats
and mice compose the largest order among the mammals.
They are called rodents or gnawers (Glires) because of
their well-known gnawing powers and proclivities. The
special arrangement and character of the teeth are char-
acteristic of this order. There are no canines, a tooth-
less space being left between the incisors and molars on
each side. There are only two incisor teeth in each jaw
(rarely four in the upper jaw), and these teeth grow con-
tinuously and are kept sharp and of uniform length by
the gnawing on hard substances and the constant rubbing
on each other. The food of rodents is chiefly vegetable.

Of the hares and rabbits the cottontail (Lepus nuttall’)
and the common Jjack-rabbit (£. campestris) are the best
known. The cottontail is found all over the United
259

MAMMALS

 

 

 

Fic. 207.—A group of moose, d/ce americana,
specimens mounted by

 

 

showing male, female, and young. (Photograph by E. Willis from
Prof. L. L. Dyche, University of Kansas.)
260 FIRST LESSONS IN ZOOLOGY

States, but shows some variation in the different regions.
There are several species of jack-rabbits, all limited to
the plains and mountain regions west of the Mississippi
River. The food of rabbits is strictly vegetable, consist-
ing of succulent roots, branches, or leaves. Rabbits are
very prolific, and yearly rear from three to six broods of
from three to six young each. There are two North

American species of porcupines—an Eastern one, Lvethz-

 

son dorsatus, and a Western one, £. efzxanthus. The
quills in both these species are short, being only an inch
or two in length, and are barbed. In some foreign por-
cupines they area foot long. They are loosely attached
in the skin, and may be readily pulled out, but they
cannot be shot out by the porcupine, as is popularly
told. The little guinea-pigs (Cazvza), kept as pets, are
South American animals related to the porcupines.

The pocket gophers, of which there are several species,
mostly inhabiting the central plains, are rodents, found only
in North America. They all live underground, making
extensive galleries and feeding chiefly on bulbous roots.
The mice and rats constitute a large family, of which the
house-mice and rats, the various field-mice, the wood-rat
(Neotoma pennsylvanica), and the muskrat (Fiber s@bethi-
cus) are familiar representatives. The common brown
rat (A/us decumanus) was introduced into this country
from Europe about 1775, and has now nearly wholly
supplanted the black rat (IZ. rattus), also a European
species, introduced about 1544. The beaver (Castor
canadensis) is the largest rodent. It seems to be doomed
to extermination through the relentless hunting of it for
its fur. The woodchuck or ground-hog (drctomys monax)
is another familiar rodent, larger than most members of
the order. The chipmunks (fig. 205) and ground-squirrels
are commonly known rodents found all over the country.
They are terrestrial members of the squirrel family, the
MAMMALS 261

best known arboreal members of which are the red squir-
rel (Sciurus hudsonicus), the fox squirrel (S. /udovicianus),
and the gray or black squirrel (S. carolinensis). The lit-
tle flying squirrel (Sczuropterus volans) is abundant in the
Eastern States.

The shrews and moles (Insectivora)._-The shrews
and moles are all small carnivorous animals, which, be-
cause of their size, confine their attacks chiefly to insects.
The shrews are small and mouse-like ; certain kinds of
them lead a semi-aquatic life. There are nearly a score
of species in North America. Of the moles, of which there
are but few species, the common mole (Scalops aquatz-
cus) is well known, while the star-nosed mole (Condylura
cristata) is recognizable by the peculiar rosette of about
twenty cartilaginous rays at the tip of its snout. Moles
live underground, and have the fore feet wide and shovel-
like for digging. The European hedgehogs are members
of this order.

The bats (Chiroptera).—The bats (fig. 209), order Chi-

roptera, differ from all other mammals in having the fore

 

Fic. 208.—Wing of bat showing elongated bones of fore limb.

limbs modified for flight by the elongation of the fore arms
and especially of four of the fingers (fig. 208), all of which
are connected bya thin leathery membrane, which includes
also the hind feet and usually the tail. Bats are chiefly
262 FIRST LESSONS IN ZOOLOGY

nocturnal, hanging head downward by their hind claws
in caves, hollow trees, or dark rooms through the day.
They feed chiefly on insects, although some foreign kinds
live on fruits. There are a dozen or more species of bats
in North America, the most abundant kinds in the East-

 

 

 

 

Tic. 209.—The hoary bat, Lasturus cinereus, (Photograph from life by
J. O. Snyder. )

ern States being the little brown bat (A/vot’s subulatus),

about three inches long,

with small fox-like face, high
slender cars, and a uniform dull olive-brown color, and
the red bat (Lasturus borealis), nearly four inches long,
covered with long, silky, reddish-brown fur, mostly white
at tips of the hairs.

The dolphins, porpoises, and whales (Cete).—The

dolphins, porpoises, and whales (Cete) compose an order
MAMMALS 263

of more or less fish-like aquatic mammals, among which
are the largest of living animals. In all the posterior
limbs are wanting, and the fore limbs are developed as
broad flattened paddles without distinct fingers or nails.
The tail ends in a broad horizontal fin or paddle. The
Cete are all predaceous—fish, pelagic crustaceans, and
especially squids and cuttlefishes forming their principal
food. Most of the species are gregarious, the individuals
swimming together in ‘“schools.’’ The dolphins and
porpoises compose a family (Delphinidz) including the
smaller and many of the most active and voracious of the
Cete. The whales compose two families—the sperm-
whales (Physeteridz), with numerous teeth (in the lower
jaw only) and the whalebone whales (Balanidz) without
teeth, their place being taken in the upper jaw by an
array of parallel plates with fringed edges known as
‘‘whalebone.” The great sperm whales or cachalots
(Physeter macrocephalus), found in southern oceans, reach
a length (males) of eighty feet, of which the head forms
nearly one-third. Of the whalebone whales the sulphur-
bottom (Lalenoptera sulfurea) of the Pacific Ocean,
attaining a length of nearly one hundred feet, is the
largest, and hence the largest of all living animals. The
common large whale of the Eastern coast and North
Atlantic is the right whale (Balena glacialis); a near
relative is the great bowhead (BL. mysticetus) of the Arctic
seas, the most valuable of all whales to man. Whales
are hunted for their whalebone and the oil yielded by
their fat or blubber. The story of whale-fishing is an
extremely interesting one, the great size and strength of
the ‘“game’’ making the “fishing ’’ a hazardous business.

The hoofed mammals (Ungulata).—The order Ungu-
lata includes some of the most familiar mammal forms.
Most of the domestic animals, as the horse, cow, hog,
sheep, and goat, belong to this order, as well as the fa-
264 FIRST LESSONS IN ZOOLOGY

miliar deer, antelope, and buffalo of our own land, and
the elephant, rhinoceros, hippopotamus, giraffe, camel,
zebra, etc., familiar in zoological gardens and menage-
ries. The order is a large one, its members being char-
acterized by the presence of from one to four hooves,

 

 

 

 

Tic. 210,—Male elk or wapiti, Cervus canadensis. Photograph by E,
Willis from specimen mounted by Prof. L. L. Dyche, University of
Kansas. )

which are the enlarged and thickened claws of the toes.

The Ungulates are all herbivorous, and have their mouar

teeth fitted for grinding, the canines being absent or

small. The order is divided into the Perissodactyla or
odd-toed forms, like the horse, zebra, tapir, and rhinoc-
eros, and the Artiodactyla or even-toed forms, like the
MAMMALS 265

oxen, sheep, deer, camels, pigs, and hippopotami. The
Artiodactyls comprise two groups, the ruminants and
non-ruminants. All of the native Ungulata of our North-
ern States belongs to the ruminants, so called because of

 

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their habit of chewing a cud. A ruminant first presses
its food into a ball, swallows it into a particular one of
the divisions of its four-chambered stomach, and later
regurgitates it into the mouth, thoroughly masticates it,
266 FIRST LESSONS IN ZOOLOGY

and swallows it again, but into another stomach-chamber.
From this it passes through the other two into the intes-
tine.

The deer family (Cervida) comprises the familiar Vir-
ginia or red deer (Odocotleus americanus) of the Eastern
and Central States and the white-tailed, black-tailed, and
mule deers of the West, the great-antlered clk or wapiti
(Cervus canadensis), (fig. 210), the great moose (Ake
americana), (fig. 207), largest of the deer family, and the
American reindeer or caribou (Raugifer caribou). All
species of the Cervida have solid horns, more or less
branched, which are shed annually. Only the males
(except with the reindeer) have horns. The antelope
(Antilocapra americana), (fig. 211), common on the West-
ern plains, also sheds its horns, which, however, are not
solid and do not break off at the base as in the deer, but
are composed of an inner bony core and an outer horny
sheath, the outer sheath only being shed. The family
Bovida includes the once abundant buffalo or bison
(Bison bison), (fig. 212), the big-horn or Kocky Mountain
sheep (Ovis canadensis), (fig. 206), and the strange pure-
white Rocky Mountain goat (Orcamnos montanius). The
buffalo was once abundant on the Western plains, travel-
ing in enormous herds. But so relentlessly has this fine
animal been hunted for its skin and flesh that it is now
practically exterminated (fig. 213). A small herd is still
to be found in Yellowstone Park, and a few individuals
live in parks and zoological gardens. In all of the Bo-
vide the horns are simple, hollow, and permanent, each
inclosing a bony core.

The carnivorous mammals (Fere).—Vhe order Ferz
includes all those mammals usually called the carnivora,
suchas the lions, tigers, cats, wolves, dogs, bears, panthers,
foxes, weasels, seals, cte. All of them feed chicfly on

animal substance and are predatory, pursuing and killing
- : Dd
267

MAMMALS

 

 

Fic. 212.—Group of American buffalo or bison (Bison b¢son), including male, female, and young.
E. Willis from specimens mounted by Prof, L, L. Dyche, University of Kansas.)

 

(Photograph by

 
268 FIRST LESSONS IN ZOOLOGY

their prey. They are mostly fur-covered, and many are
hunted for their skin. They have never less than four
toes, which are provided with strong claws that are fre-
quently more or less retractile. The canine teeth are
usually large, curved, and pointed.

While most of the Fer live on land, some are strictly
aquatic. The true seals, fur-seals, sea-lions, and wal-

 

 

Fic, 213.—A buffalo, Arson dison, killed for its skin and tongue, on the
plains of Western Kansas thirty years ago. (Photograph by J. Lee
Knight.)

ruses comprise the aquatic forms, all being inhabitants of
the ocean. The true seals, of which the common harbor
seal (Phoca vitilina) is our most familiar representative,
have the limbs so thoroughly modified for swimming that
they are useless on land. The fur-seals, sea-lions, and
MAMMALS 269

walruses use the hind legs to scramble about on the rocks
or beaches of the shore. The fur-seals (fig. 214) live
gregariously in great rookeries on the Pribilof or Fur Seal
Islands, and the Commander Islands in Bering Sea. The
bears are represented in our country by the widespread
brown, black, or cinnamon bear ( Ursus americanus) and
the huge grizzly bear (UV. horribilis) of the West. The
great polar bear (Thalarctos maritimus) lives in arctic
regions. The otters, skunks, badgers, wolverines, sables,
minks, and weasels compose the family Mustelidz, which
includes most of the valuable fur-bearing animals. Some
of the members of this family lead a semi-aquatic, or even
strictly aquatic, life and have webbed feet. The wolves,
foxes, and dogs belong to the family Canidez. The coyote
(Cants latrans), the gray wolf (C. xubzlus), and the red
fox (Vulpes pennsylvanicus) are the most familiar repre-
sentatives of this family, in addition to the dog (C. famz-
liarts), which is closely allied to the wolf. ‘Most car-
nivorous of the carnivora, formed to devour, with every
offensive weapon specialized to its utmost, the Felide,
whether large or small, are, relatively to their size, the
fiercest, strongest, and most terrible of beasts.’’ The
Felidz, or cat family, includes the lions, tigers, hyenas,
leopards, jaguars, panthers, wildcats, and lynxes. In this
country the most formidable of the Felide is the Amer-
ican panther or puma (Felis concolor). It reaches a length
from nose to root of tail of over four feet. Its tail is long.
The wildcat (Lyx rufus) is much smaller and has a short
tail.

The man-like mammals (Primates).—The Primates,
the highest order of mammals, includes the lemurs, mon-
keys, baboons, apes, and men. Man (Homo sapiens) is
the only native representative of this order in our coun-
try. All the races and kinds of men known, although
really showing much variety in appearance and body
ST LESSONS IN ZOOLOGY

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MAMMALS 271

structure, are commonly included in one species. The
chief structural characteristics which distinguish man from
the other members of this order are the great develop-
ment of his brain and the non-opposability of his great
toe. Despite the similarity in general structure between
him and the anthropoid apes of the Old World, in par-

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Fic. 215.—‘‘ Bob Jordan,” a monkey of the genus Cercopithecus. (Photo-
graph from life by D. 5S. Jordan.)
ticular the chimpanzee and orang-outang, the disparity in
size of brain is enormous.
The lowest Primates are the lemurs found in Madagas~
car, in which island they include about one-half of all the
272 FIRST LESSONS IN ZOOLOGY

mammalian species found there. The brain is much less
developed in the lemurs than in any of the other monkeys.
The monkeys and apes may be divided into two groups,
the lower, platyrrhine monkeys, found in the New World,
and the higher, catarrhine forms, limited to the Old
World. The platyrrhine monkeys have wide noses in
which the nostrils are separated by a broad septum and
with the openings directed laterally. These monkeys are
mostly smaller and weaker than the Old World forms and
are always long-tailed, the tail being frequently prehen-
sile. They include the howling, squirrel, spider, and
capuchin monkeys common in the forests of tropical
South America. The catarrhine monkeys have the nose-
septum narrow and the openings of the nostrils directed
forwards, and the tail is wanting in numerous members of
the group. They include the baboons, gorillas, orang-
outangs, and chimpanzees. These apes have a dentition
approaching that of man, and in all ways are the animals
which most nearly resemble man in physical character.

Interesting accounts of the lives of familiar mammals
are given in three books by Wm. T. Long, entitled ‘‘ Ways
of Wood Folk,’’ ‘‘ Wilderness Ways,’’ and ‘‘ Secrets of
the Woods.’’
PART IV

ANIMALS IN RELATION TO EACH OTHER
AND TO THE OUTSIDE WORLD

CHAPTER XVII

THE STRUGGLE FOR FOOD AND ROOM, AND
THE SPECIAL MEANS FOR FOOD-GET-
TING AND PROTECTION

The multiplication of animals.—The English sparrow,
now a common bird over our whole country, rears five or
six broods every year, each brood containing six to ten
young. That is, each pair of healthy English sparrows
produces from thirty to sixty new sparrows each year.
Now if all these young come safely to maturity and each
pair maintains the same rate of increase, and every spar-
row lives to its normal age, how long will it take to cover
the face of the land with these pugnacious, noisy, little
birds? As a matter of fact a professor of mathematics
has solved this problem, and finds that at the normal rate
of increase, and if no sparrows were to die save naturally
of old age, it would take about twenty-five years to give
one sparrow to every square inch in the United States.

But English sparrows are not the only birds in the
country, and although the robins, bluebirds, woodpeckers,
and the scores of other kinds do not lay so many eggs
nor lay so many times a year, yet each pair does produce
more than two eggs yearly, that is, each pair yearly mul-

273
274 FIRST LESSONS IN ZOOLOGY

tiplies, not simply replaces itself. Most birds, however,
are slow multipliers. But what of the host of insects
where each female lays from a few dozen to many hun-
dred or even thousand eggs each year; and the fishes,
almost none of which lays less than several thousand a
year? A few years of uninterrupted normal increase
among sunfishes would fill every stream and pond solidly
full of them. Even certain of the tiniest animals, micro-
scopic animalcules which live in the ocean, if left to mul-
tiply at their usual rate with no losses except by natural
death, would, it has been estimated, completely fill the
ocean in about a week!

Of course no such appalling increase in the number of
living animals occurs, although we may fairly consider
that each kind of animal is constantly trying to usurp far
more food and space in the world than it now has. But
there are about as many squirrels in the forest one year as
another, about as many butterflies in the field, aboutas many
frogs in the pond. Sometimes a particular kind of ani-
mal gets into a new part of the world and suddenly mul-
tiplies with great rapidity. A few rabbits were introduced
into Australia (where there were none) in 1860, and in
fifteen years had become so abundant as to be a great
pest. The government pays large sums in bounties
every year to rabbit-hunters.

The struggle to live.—All animals tend to increase in
geometrical ratio, that is, the production of new indi-
viduals is by multiplication, not by simple addition.
But food and space on the earth have definite limits, and
so there is constantly going on a great struggle for exist-
ence. In the case of any individual the struggle is
threefold; (1) with the other animals of his own kind
or species for food and room; (2) with other kinds of
animals which want the same food and space, or which
may want him for food; and finally, (3) with the condi-
THE STRUGGLE FOR FOOD AND ROOM 275

tions of life, such as cold and heat, and drouth and flood.
No living being can escape from this struggle. Each
strives to feed itself, to save its own life, to produce and
protect its young. But in spite of all their efforts only a
few individuals out of the hundreds and thousands born
live to maturity. The great majority are killed in the
egg stage, or during adolescence.

Selection by nature.—What individuals survive of the
many which are born? Those best fitted for life; those
which are a little stronger, a little swifter, a little hardier,
a little less readily perceived by their enemies than the
others. We know from our observation of a brood of
young kittens or puppies that there are differences in new-
born individuals of the same kind, and even among those
born from the same mother. Thus it is with all animals.
No two individuals even in the same brood are exactly
alike at birth. And the very few members of each brood
which do survive are almost always the hardier, stronger,
and swifter. They are the winners in the struggle for
existence. And this survival of the fittest, as it is called,
is practically a weeding out or selecting process of Na-
ture. She selects the fittest to live and to perpetuate
their kind. Their young in turn must undergo the strug-
gle and the selecting process, and again the fittest live.
And so on until the adjustment or harmonizing of the
bodies and habits of animals with the conditions of their
life, their environment, comes to be extremely fine and
nearly perfect.

Special means to get food.—With such a constant
struggle, such a race for food, it is not strange that we
find different animals having various kinds of special
arrangement for getting it. Those which live on plants
can get it in two ways, either by biting off the green
leaves and stems and crushing them in the mouth, or by
thrusting a sucking beak into the plant tissue and draw-
276

ing out the sap.

  
 
  
   
  

 

FIRST LESSONS IN ZOOLOGY

So the different plant-feeding animals

have the mouth specially arranged
for one or the other of these ways.
Cattle and horses and sheep have
teeth for biting off and crushing
dry or green plant food, while
many insects, like the plant-lice
and various flower-bugs, have a
tiny, sharp, hollow beak, which
they thrust into a green leaf or
stem, and through which they suck
upthesap. Similarly with those ani-
mals which feed on animal matter.
Lions, tigers, dogs, and cats have
strong teeth for tearing and broad
teeth for crushing the flesh of
other animals, while the mosquito,
flea, and other insects which live
principally on animal blood have
a piercing and sucking
beak.

But animals must
first obtain their food.
Giraffes get theirs from
high trees and they
have wonderfully long
necks to enable them
to reach up; the moths
and butterflies which
feed on nectar from

Itc. 216,—Sucking proboscis of a sphinx- flowers have long,

moth;

in small figure the proboscis is
shown coiled up on the under side of the

slender sucking-tubes

head, the normal position when not in use. with which to reach

(One-half natural size; from specimen.)

flower-cup.

down to the base of a

The common hawk-moths or humming-bird
THE STRUGGLE FOR FOOD AND ROOM 277

moths that hover over petunias and other deep-cupped
flowers have sucking-tubes three or four inches long
(fig. 216), and a famous member of this family in Mada-
gascar has its sucking-tube fourteen inches long, which
enables it to reach to the bottom of a great trumpet-
shaped flower. Lions and tigers, wolves, and the like
which feed upon other live animals must have specially
developed legs and muscles for swift running, or spring-
ing, or swimming. The otter can swim and dive better
than most fishes, and with
his greater cleverness has
little difficulty in capturing
the swiftest of them. The
eagle has great talons for
grasping its prey,andastrong
hooked beak for tearing it.
The pelican has a large
pouch or sac on its lower jaw
which it uses as a scoop-net
for catching fish. Thespoon-
bill duck takes up mouth-
fuls of mud and water which
it strains out through a close
fringe of small thin plates
at the sides. The preying
mantis (fig. 217) has great
spiny fore legs for seizing its prey, the unwary house-flies,
on the window-panes, while the dragon-fly has a large
mouth which it can open very wide, and can engulf in
this fatal trap many tiny midges as it flies swiftly through
their dancing swarms.

Special means for protection.—Some animals have
poison-fangs, like the rattlesnake and the ugly lizard of
the desert called Gila monster, and others stings, like the
scorpion, to kill their prey. These weapons are of course

 

Fic. 217.—Preying mantis. (Natural
size; from specimen.)
278 FIRST LESSONS IN ZOOLOGY

also used in self-defense. The same is true also of

numerous other special means of

 

 

 

 

 

Fic. 218.—Bay-worm; the larva of a moth
that builds a protecting case out of silk
and bits of sticks, in which its whole
body, except horny head, thorax, and
legs, is concealed. (Natural size; from
specimen. )

food-getting, such as the
power to run swiftly, to
leap, and swim. But
there are in addition
many special means of
defense and protection
which have nothing to
do with food-getting.
The males of most mem-
bers of the deer family—
the moose, elk, and red
deer for example—have
antlers strong and sharp-
pointed, which they can
use effectively in fighting
wolves and other enemies
as well as each other.
At the same time they
have legs finely devel-
oped for swift running,
and to run away is often
better protection than to
fight. The porcupine has
long, sharp quills which
make a bad mouthful for
any animal that attempts
to nip the prickly ball ;
the armadillo of tropical
countries has its body
covered with horny
shields, and when _ it

draws in its head and curls up tightly it is as well protected

as a turtle in its box-like armor.

Numerous fishes have

other means of protection besides their ability to swim
THE STRUGGLE FOR FOOD AND ROOM 279

swiftly; the catfishes stiffen a long spine in each pectoral
fin, which makes a bad wound ; the so-called poison-fishes
of the ocean have spines provided with poison glands; the
sting-rays, common on the coast, have a strong, jagged
spine in the tail, armed with broad saw-like teeth, which
inflicts a bad, ragged cut. The torpedoes or electric
rays found on the sandy shores of all warm seas have on
each side of the head a large honeycomb-like structure
which gives a strong electric shock whenever the live fish
is touched. Among the reptiles of our country the poi-
sonous bite of the rattlesnake, copperhead, and water-
moccasin is a familiar example of a very effective special
means of defense.

Certain special habits of animals, too, help much to
protect them, and to save their lives. The migration of
birds takes many from a bleak, foodless winter to the
luxuriant tropical forests, where there is plenty of food
and the weather is mild. The hibernation or ‘‘ winter
sleep’ of bears, snakes, and lizards carries them safely
through a season when food is scarce or wanting alto-
gether. And some animals come from their holes and
hiding-places to hunt food only at night, when most of
their enemies are asleep.

Finally (as we shall learn particularly in the next
chapter), many animals are colored and marked in such
manner that they match or fit in so well with the soil or
leaves or stones on which they rest as to be indistinguish-
able. And this scheme of harmonious coloration is one
of the most successful and wide-spread of all the special
protective devices.

Examples to be looked for by the pupils.—Only a
few of the special means for food-getting and protection
are mentioned in this chapter, and those animals which
may be most readily observed by the pupils have pur-
posely not been referred to. When we come upon such
280 FIRST LESSONS IN ZOOLOGY

a peculiar device as the long neck of the giraffe or the
fishing-pouch of the pelican our attention is specially at-
tracted, and we are likely to consider such cases unusual
and exceptional. But they are not exceptional, they are
simply unusual and unfamiliar and specially conspicuous.
All animals, including all those we know best, have
special means of food-getting and protection, and many
of them, particularly the insects and birds, have just as
unusual and just as wonderful and interesting devices
as any mentioned in the preceding paragraphs. Let
each pupil observe carefully and thoughtfully the ani-
mals familiar and accessible to him, remembering that
smallness does not at all mean lack of wonderful and
interesting structures and habits. Let each make a list
from personal observation of the special devices and
habits for getting food and for protection possessed by
the animals he knows.
CHAPTER XVIII

COLORS AND MARKINGS OF ANIMALS, AND
THEIR USES

The colors and markings of animals are among the
most conspicuous of their external characters, and con-
stantly incite us to ask how they are produced and why
they are of such great variety. As no more familiar or
interesting examples of color patterns can be found than
those on the wings of butterflies and moths, we can very
advantageously use these beautiful insects in beginning
the study of animal colors.

The scales and colors of butterflies’ wings.—Catch a
few butterflies of different kinds and kill in the killing-bot-
tle. With the finger rub lightly one of the wings and
note that a fine dust-like substance comes off on the
finger-tip, and that at the same time the pattern and color
disappear. By gentle steady rubbing with thumb and
finger just opposite each other on the upper and lower
sides of the wings, a clear, transparent spot may be made.
It is evident that the color and pattern of the wing de-
pends upon its covering of fine particles.

Rub some of this color-dust from the finger-tip on a
glass slide and examine under the microscope. Note that
the fine particles are all scale-like in shape and character,
each being composed of a tiny short stem and a broader
flattened blade which may have the margin of its broad
free end even or dentate, that is, showing little teeth or

fingers (fig. 220). These tiny scales are hollow and inside
281
N
oo
N

FIRST LESSONS IN ZOOLOGY

they may contain only air, in which case they are trans-
parent or whitish under the microscope, or they may
hold small granules of pigment, a colored substance
which makes them brown or yellowish or reddish or
blackish.

Some butterflies have blue or green or purple colors,
irridescent and changeable, on their wings. The common

 

 

 

 

 

Fic, 219.—Owl-buttertly (Ca/igo), under side. (Two-thirds natural sizc;
photograph by the author.)

little ‘‘blues’’ have the upper side of the whole wing
metallic blue. Examine under the microscope some
scales from one of these blue wings, or from a blue or
greenish iridescent spot on any butterfly’s wing. They
will be seen to be not blue or green (as long as light is
allowed to come from the mirror of the microscope up
through them) but either colorless or of a pale yellowish
COLORS AND MARKINGS OF ANIMALS 283

or brownish shade. But if the light from below is cut off
by placing a hand over the microscope mirror they will
show an iridescent blue or green.

 

l1G, 220.—Single scales from moths and butterflies; a, from Tolype velleda;
6, from Castnia sp.; ¢, from ALicrepteryx aruncella. (Greatly magni-
fied; from specimens. )

Examine under the microscope a bit of wing from which
most of the scales have been rubbed (figs. 221 and 222).

 

Fic, 221.—A small, partly denuded part, much magnified, of a wing of | a
“blue” butterfly, Zyeena sp., showing the wing. scales, and the pits
in the wing-membrane, in which the tiny stems of the scales are in-
serted. (Photomicrograph by Geo. O. Mitchell.)

Note rows of tiny pits or pockets in which the stems of
the scales fit. The scales are fastened, though not very
284 FIRST LESSONS IN ZOOLOGY

firmly, to the wing membrane by their stems, and are
arranged in fairly even rows. In each row they are so
thick that they overlap
each other’s sides, and the
rows are so close together
that the tips of the scales
of one row overlap the
bases of those of the one
in front. This arrange-
ment is much like that of
shingles on a roof, and
each wing is thus shingled

 

above and below (fig. 223)
Fic, 222.—Bit of denuded wing of a by thousands of tiny scales

butterfly, Grapra, greatly magnified,
to show rows of insertion pits on
upper and lower sides, and three ors and markings. These
scales. (From specimen. )

which produce all its col-

colors are made in two
ways; either the scales are actually brownish or reddish
or yellowish or black themselves because they contain
pigment granules inside, or else they reflect white light in
such away that it is broken up, as bya prism, into colors,
only some of which reach our eyes. The metallic and
iridescent kinds, the greens, blues, coppers, purples, etc.,
all of which change somewhat as we change the position

 

Fic. 223.—Diavram to show shingling arrangement of scales over surface

223.
of butterfly’s wing; the short black bars indicate scales in cross-section,
the broad central bar, the wing in cross-section.

of our eyes, are produced in the second way. The duller
and the fixed colors, such as the reds, yellows, browns,
ctc., are produced by scales containing pigments of the

same shade.
COLORS AND MARKINGS OF ANIMALS 285

Colors of other animals.—The colors of other animals
are also produced in one or both of these two ways; that
is, either by colored pigment, or by reflections from
structures which act as the prism does. Only a few
other animals have scales, and almost no others have
scales just like those of the butterfly, but they have other
kinds of structures on the outside of the skin, such as
feathers or hairs, which contain pigment, or break up
white light into colors.

Observe the coloring on a blackbird; note the fine iri-
descent blue and purple or bronze-green reflections.
These are made by the feathers reflecting broken-up
white light. Such iridescent colors produced by struc-
ture, and hence called structural colors, are especially
pronounced and beautiful on humming-birds. On the
other hand the red brown of the robin’s breast and the
yellow of the meadow-lark’s are produced by feathers
containing reddish and yellowish pigment granules.

The colors of most quadrupeds, which are covered with
hair, are dull and almost entirely due to pigment in the
hair. Those of live fishes, often brilliant and iridescent
in the water, fade and sometimes wholly disappear when
the fish is dead and dry. Colors such as these are struc-
tural, the scales being mostly transparent.

Observe as many animals as possible and try to find
out how their colors and markings are produced, what
the external structures are which make them, and whether
they are made by pigment or by prismatic reflection.

Uses of color.—Although we have been long accus-
tomed to see the beautiful and varied markings of birds
and butterflies, have we asked ourselves of what use these
colors and patterns are to the animals possessing them ?
We cannot think that they exist just to please us. We
have found that in animals’ bodies the parts are all made
so as to be just as useful as possible, each part having
n

86 FIRST LESSONS IN ZOOLOGY

some special thing to do to help the animals along. The
same is true of the colors and patterns which are such
conspicuous features of their external appearance.

Try to catch a locust. The insect will be plainly seen
as it flies or leaps through the air, but how when it alights
on the ground? If you do not watch carefully to see it
alight, you will have great difficulty in finding it now.

 

Fic. 224.—The death’s-head sphinx-moth; note skull-like markings on thorax
(between wings). This moth is lookcd on with superstitious dread by
many people, (Natural size; photograph by the author. )

It is almost indistinguishable among the pebbles, bits of
twigs, and soil of the surface. It resembles its surround-
ings in coloration and undoubtedly is thus often saved
from pursuing enemies. A bird sees a locust flying. The
locust alights and rests quietly on the ground; if distin-
guished the bird scizes it and it loses its life; if not dis-
tinguished the locust is saved, and saved by its color.
So color is of use to the locust.

Rut how about the birds themselves~.the crouching,
COLORS AND MARKINGS OF ANIMALS 287

immovable, dust-colored quail which waits until the hawk,
not perceiving it, flies away; and the rabbit, colored

like the dead grass and
ground about it, which lies
rigid until you are fairly
upon it, although it sees
your every movement?
Swift of foot as the rabbit
is, it relies more for safety
on its protective color than
on its fleetness. Among
the green leaves of trees
live the katydids; they are
On the great
everlasting snow-fields of
the arctic regions live foxes
and hares and ptarmigan,
all white as the snowitself,
although their near cousins
the foxes, hares, and ptar-
migans of warmer regions,
where the snow falls but
occasionally, and the earth
surface is usually brown
and dark, are reddish or
gray or brown. In the
desert the lizards and
snakes and insects are
mottled gray and sand-
colored, while in the ever-
green foliage of trees in
warm regions live green

all green.

 

 

Fic, 225.—The twig or walking-stick

insect, Diapheromera femorata
(From specimen. )

tree-frogs and tree-snakes and insects.
Special protective resemblance.—But some animals
show more than just a general resemblance to, or har-
288 FIRST LESSONS IN ZOOLOGY

mony with, the color tone of their surroundings; they
show a striking resemblance to some particular part of
their surroundings. An insect common all over the
country, but only rarely distinguished and recognized, is
the walking-stick insect (fig. 225). Its body is long and
slender, its legs very long and held stiffly and angularly,
and it has no wings. Its body and legs are colored
either dull green all over, or blackish brown. And when
not walking slowly about it always rests quietly on a
twig or branch, from which the eye with difficulty sepa-
rates it. In the tropics the so-called green-leaf insect,
Phyllium, resembles in great detail a broad green leaf.
Its body is broad and leaf-shaped, its color bright green
with delicate lines to imitate the midrib and veins of a
leaf, and it even has pale irregular yellow spots
which imitate mouldy and yellow places on a real leaf.
3ut most remarkable of all is the famous dead-leaf insect,
Kallima (fig, 226), not uncommon in tropical Africa,
South America, and the Australasian islands. The upper
surfaces of the wings of this butterfly are brownish gray
with a broad purplish bar on each wing, making a rather
conspicuous pattern; but the under sides are so colored
and are marked with such faithfulness of detail that when
Kallima alights and folds its wings together above its
back, as butterflies do, it resembles exactly a large, brown,
dead leaf, still attached to the twig by a short pedicel or
stem (imitated by a ‘‘tail’’ on the hind wings). The
mock leaf is veined by means of lines of darker scales
exactly as leaves are veined.

In this country are certain butterflies, the Graptas,
sometimes called dead-leaf butterflies, which resemble in
color and shape, and in the ragged edges of the wing,
dead and torn autumn leaves, but the resemblance is not
carried out in such detail as with Kallima.

Warning colors.—But not all insects or other animals
COLORS AND MARKINGS OF ANIMALS 289

 

Fic. 226.—The dead-leaf butterfly, A@//ima sp., a remarkable case of special
protective resemblance (From specimen.)
290 FIRST LESSONS IN ZOOLOGY

are colored like their surroundings. Often indeed color and
pattern are such as to make an animal very noticeable.

 

Fic. 227.—larva of the monarch butterfly, conspicuously marked with
black and whitish-yellow rings, and distasteful to birds. (Natural
size; from specimen. )

The common large red-brown monarch, or milkweed
butterfly (fig. 228), isa conspicuous object whether in flight

 

Fic, 228.—The monarch butterfly, fyvosta plexippus (above), distasteful to
birds, and the viceroy, Basélarchia archippus (below), which mimics
it. (Irom specimens. )

or alighted on some flower or branch. But the birds do
not attack it; and for this reason, that it contains, as has
COLORS AND MARKINGS OF ANIMALS 2Qg1

been proved, an ill-tasting fluid which makes it a very
disagreeable mouthful for them. Now itis apparently so
brightly colored that the birds generally recognize it be-
fore actually nipping it, and thus it often escapes with its
life—for to be nipped is death to a butterfly. Other con-
spicuously marked butterflies and insects and some other
forms, in particular a famous little blue and red frog of Nic-
aragua, are thought to be so marked for a similar reason.
They are easily recognized as animals having a bad taste
and so are generally let alone. Accordingly naturalists
believe that conspicuous color and markings often adver-
tise some disagreeable quality or some special means of
defense in the animal bearing them and thus ward off its
enemies.

Mimicry.—Certain other insects derive strange advan-
tage from the inedibleness of the warningly colored bad-
tasting kinds. There is, for example, another kind of
butterfly called the viceroy (fig. 229), which looks so
much like the monarch (although not nearly related to it),
that it requires careful examination to distinguish the two
kinds. But the viceroy is not inedible. And yet it, too,
escapes very largely the attacks of birds because they
mistake it for the other. By mimicking in color and pat-
tern the appearance of the inedible monarch it gains a
great advantage. Numerous other examples of protective
mimicry are known among butterflies, especially tropical
ones.

Other uses of color and marking not yet understood.
—Protective resemblance and mimicry and warning col-
oration do not account for the color-markings of all ani-
mals, although it is probably true that the most wide-
spread use of color in the animal kingdom is for protec-
tive resemblance. For example, the conspicuous white
spot on the rabbit’s tail is thought by some naturalists to
be a means whereby it can be recognized by others of its
292 FIRST LESSONS IN ZOOLOGY

kind at long distances. Some naturalists believe that
the bright colors and conspicuous markings of male birds
are for the purpose of pleasing and attracting the females

 

 

 

 

 

Fic. 229,—Various moths and wasps, the moths having the appearance of wasps,
probably through mimicry, and protected by being mistaken tor the stinging
insects. (Natural size; photograph by the author.)

at mating time. And still other uses have been ascribed
to color-markings in various animals. But with all these
different explanations there are still many cases for which
we can give no satisfactory explanation based on uscful-
ness. There is much yet to be learned about color and
pattern in animals.

Poulton’s the ‘‘Colors of Animals’? is an interesting
book on this subject; see also Newbigin’s ‘‘ Color in
Nature,’’ and Beddard’s ‘* Animal Coloration.’’
CHAPTER XIX

ANIMAL PARASITES

An animal parasite is an animal which lives and feeds
for all or part of its life on or in the body of another
which is called the host. Fleas, dogticks, and lice are
familiar parasites; they are not very pleasant to think
about perhaps, but their mode of life is interesting be-
cause it presents one way of getting a living which has
been adopted by many different kinds of animals, and
which always results in a more or less marked change in
their structure. This change usually involves the loss
or imperfect development of some part of the body.

Degeneration of parasites.—Fleas and lice are insects,
but, unlike most of their kind, they have no wings.
Being carried about by the host they do not need to fly.
One of the most striking examples of loss of parts due to
a parasitic habit is shown by an animal called Sacculina
(fig. 231), which belongs to the crab and crayfish group.
The young Sacculina, hatched from eggs laid in ocean
tide-pools, has legs and eyes and a mouth and feelers,
and can swim actively about. It looks much like a
young crab or prawn. But after a short period of free
active life it finds a full-grown crab and attaches itself
to its body. There grow out from the Sacculina and
penetrate the body of the crab slender root-like processes
by means of which the parasite sucks up the juices of its
host. Soon it moults and loses its legs, eyes, and feel-
ers; it is now simply a pulsating tumor-like sac fastened

293
FIRST LESSONS IN ZOOLOGY

294

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ANIMAL PARASITES 295

to the crab by means of the feeding rootlets. Loss by
degeneration of the body-parts is carried very far in this
case. ;

Internal parasites.—Inside the body of most animals
live various parasites belonging to the great branch of

 

Fic. 231.—Sacculina, a parasitic crustacean; A, attached to a crab, the
root-like processes of the parasite penetrating the body of the host ; 4,
the active larval condition; C, the adult removed from its host.
(After Haeckel.)

worms. The tapeworm and the deadly trichina (see

p. 146) are conspicuous examples of these. The tape-

worm (fig. 233) has the form of a narrow ribbon, perhaps

several yards long, attached at one end to the wall of

the intestine, while the remainder hangs freely in the
2096 FIRST LESSONS IN ZOOLOGY

interior. Its body is composed of segments or serially
arranged parts, of which there are about 850 altogether.
It has no mouth or stomach. It feeds simply by absorb-
ing into its body, through the skin, the nutritious already
digested food in the intestine of its host. It has no eyes
or other special sense-organs, nor any organ of locomo-

      
 

  
  

iy wo SS B®

tC

 

Fic. 233.

Fic. 232.—Trichina spiralis, encysted in muscle of a pig. (Greatly magni-
fied; from specimen. )

lic, 233.—Tapeworm; head magnified, at left; whole worm may be
several yards long. (After Leuckart.)

tion. Thus its body is very degenerate. The life-his-
tory of the tapeworm is interesting, because it lives in two
hosts during its life. The eggs of this parasite pass from
the intestine with the excreta, and to develop must be
taken into the body of some other animal. In the case
of one of several species infesting man this second host
ANIMAL PARASITES 207

is the pig. In the alimentary canal of the pig the young
tapeworm develops, to bore its way later through the
walls of the canal and become imbedded in the muscles.
There it lies until the diseased flesh containing it is eaten
(without being perfectly cooked), and it thus finds its way
into the alimentary canal and thence into the intestine of
man. It now continues to develop until it becomes full
grown.

Parasitic insects.—Among the insects many live as
parasites during their immature or larval life, but as adults
are free and independent creatures. From the chrysalid
of a butterfly or moth there will often come not a butter-

 

Fic. 234.—Larva of a sphinx-moth, with cocoons of a parasitic ichneumon
fly. (From specimen.)

fly but numerous tiny four-winged gnats, called ichneumon
flies. This is what happened. When the butterfly
caterpillar was crawling about a female ichneumon darted
down on it, and with her sharp ovipositor either laid
several eggs beneath its skin or glued them to its outer
surface. These eggs hatched in two or three days as
tiny white ichneumon grubs, which immediately burrowed
deep into the caterpillar and lay there feeding on the
blood and tissues of its body. But the caterpillar went
on eating and finally changed into a chrysalid, with the
ichneumon grubs still inside. Soon the grubs, having
eaten up most of the body of the developing butterfly
and thus killed it, changed into tiny pupz, and later into
298 FIRST LESSONS IN ZOOLOGY

fully developed ichneumon flies which gnawed their way

out through the horny case of the dead chrysalid.
Sometimes yellow-jackets are infested by a strange

parasitic beetle called Stylops. The adult male Stylops

     
   

    

+ aS - le i
n Za ; au
MZ ‘i sb

Fic. 235.—Caterpillar killed by parasitic ichneumon flies which have left
the body through small holes in the skin. (Natural size; from
specimen. )

beetles have four wings, but the females are wingless.

The young Stylops, a grub or larva, attaches itself to a

wasp or bee and burrows into its abdomen. Here it

pupates and lies with its head projecting slightly from a

 

Fic. 236. Fic. 237.
Fic. 236.—The pigeon horn-tail (7remex). (Natural size; from specimen. )
Fic. 237.—7halessa drilling into the burrow of Zremex. (Natural size;
after Comstock. )

slit between two of the body-rings of the wasp. Finally
the adult Stylops issues and deserts the body of its host.

One of the most interesting ichneumon flies is Tha-
lessa, which has a remarkably long, slender, flexible
ANIMAL PARASITES 299

ovipositor. Another insect, known as the pigeon horn-
tail (fig. 236), upon which Thalessa preys, deposits its eggs
by means of a strong, piercing ovipositor, half an inch
deep, in the trunks of growing trees. The young or larval
horn-tail hatches as a soft-bodied white grub, which
bores more deeply into the tree,
filling up the burrow behind it with
small chips. When a female Tha-
lessa finds a tree infested by the
horn-tail she selects a place which
she judges is opposite one of its
burrows, and elevating her long
ovipositor in a loop over her back,
with its tip on the bark of the tree,
she makes a derrick out of her body
and proceeds with great skill and
precision to drill a hole (fig. 237).
Having reached the horn-tail’s bur-
row she deposits an egg init. When
the larva hatches it creeps along Fic. 238.—A_ bird-louse
the burrow until it reaches and ie elma
fastens itself upon the larval horn- (About one-twelfth inch
tail which it destroys by sucking its Poe ma
blood. When full grown it changes
to a pupa within the burrow of its host, and finally the
adult Thalessa gnaws a hole out through the bark if it
does not find the one already made by the horn-tail.
Almost all birds are infested with small, flattened,
wingless, parasitic insects which live among the feathers,
and feed by biting off small bits of barbs. Chickens and
pigeons are specially infested by these biting bird-lice
(called biting to distinguish them from the common true
lice of other animals, which have a piercing beak and
suck blood) (fig. 238). Specimens of these parasites
should be obtained and examined under a microscope to

 
FIRST LESSONS IN ZOOLOGY

300

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onisered @ Aq pal[ry ‘vag Surmag ‘puxsy [Neg ‘Ig ‘ATayxOor 10}s[OJ, ay} JO ‘svzeesan snusysoyvy ‘s|vas-AUJ

Suno,—6tz ‘org

 

 

 
ANIMAL PARASITES 301

note the absence of wings and compound eyes, and the
peculiarly shaped body well fitted for swift running among
the feathers. Note bits of feathers in the stomach show-
ing through the body-wall.

There are many other examples of parasitic life to be
found among common and familiar animals. Careful
watch for them should be kept by the pupils in their
field work and in their rearing of insects and other ani-
mals in the schoolroom.

For an account of many parasites see Van Beneden’s
«« Animal Parasites and Messmates.’’
CHAPTER XX

THE HONEY-BEE AND OTHER SOCIAL
ANIMALS

We have learned (Chapter XVII) of the great struggle
going on in the animal world for room and food. We
know that each animal has to battle against adverse
physical conditions, such as cold and heat, drouth and
flood; against other kinds of animals which try to occupy
the same region and to eat the same food that it does;
and finally, with other individuals of its own kind, its own
brothers and sisters and cousins indeed, which compete
for the room and food that can support but few of them.
But in this great threefold struggle some one phase may
be much less severe than the others, or, indeed, as occurs
in some cases, with individuals of the same kind it may
be to a certain extent replaced by a relation of mutual
helpfulness. That is, the individuals of a certain species
may and do adopt a social or communal life, helping
each other to get food, to build homes, and to fight off
enemies. Of these social animals the honey-bee is the
most familiar and one of the best examples. The ants,
too, are well-known communal animals.

The life of a honey-bee.—In studying the life of the
honey-bees one must observe them in the hive as well as
in the field. It is therefore highly desirable to have an
‘« observation ”’ hive (fig. 240), 1.e., one made with glass
sides and glass top, covered with outer wooden sides which
are swung on hinges like doors, and with the usual remov-

302
THE HONEY-BEE AND OTHER SOCIAL ANIMALS — 303

able wooden roof. Ordinarily the wooden sides and top
are closed, thus leaving the hive in darkness. However,
when it is desired to observe the bees at work within, the
wooden sides are swung open; the glass still incloses the
busy community, but affords an opportunity to see the
actual performance of such interesting duties as wax-
making, comb-building, food-storing, egg-laying, nurs-
ing, etc. An observation hive may be obtained from a
dealer in beehives or be made out of an ordinary hive

 

Vic. 240.—An ‘‘observation”’ beehive with glass top and sides. (Drawn
from hive in the author’s laboratory. )
by any carpenter or ingenious boy. It should be set up
in the spring. It can be kept in the schoolyard, or even
better, in the schoolroom itself. Substitute for a pane of
glass in a window a thin wooden pane in which is cut a
narrow horizontal opening, the size of the regular hive
opening. If the latter is too broad it may be covered
over at the ends. Set the observation hive on a table
or box against the window so that its opening corre-
sponds with that in the window. Or better, place it
about six or eight inches from the window and build an
304 FIRST LESSONS IN ZOOLOGY

inclosed broad shallow tunnel, covered above with glass,
connecting the two openings. Over the glass top of the
tunnel lay a sheet of dark cardboard, which can be
simply lifted off whenever it is desired to see what is
going on at the entrance. Here can be seen the ‘‘ ven-
tilating,’’ the alertness of the sentinels and guards, the
killing of drones, the constant arrival of pollen-laden
food-gatherers, etc.

But observations may well begin in the field (fig. 241).
Note the gathering of flower pollen. Where does the bee

 

 

 

 

put the pollen as it collects it? Why doesn’t the pollen
fall off? Kill a bee in a killing-bottle and examine care-
fully one of its hind legs. Make a drawing showing the
pollen basket. At the flowers some of the bees do not
collect pollen but nectar. Where do they find it, and
how do they collect and carry it? Examine the complex
‘*tongue ’’ of a dead bee. By means of this tongue nec-
tar is sucked or lapped up and swallowed into a crop,
where it is not digested but retained until the bee returns
to the hive. By observing the bees there and examining
THE HONEY-BEE AND OTHER SOCIAL ANIMALS — 3°95

the comb-cells find out what is done with the pollen and
nectar collected by the food-gatherers.

Try to observe the making of wax and the building of
comb in the hive (fig. 242). The process is as follows:
After having fed bountifully on honey and pollen from the
food cells a number of bees gather together at the top of
the hive and there hang in a mass, usually buzzing the
wings violently. After a while small drops of liquid wax
ooze out on the under side of the body. There are

 

 

Fic. 242..-Honey-bees building comb. (From Benton.)

several pairs of small scale-like folds of the skin, called
wax plates, on the under side of the hinder or abdominal
body-rings. On these plates the wax spreads out and
hardens into tiny thin sheets. After some of it has been
made by a bee it leaves its wax-making companions and
goes to the place where a new comb is to be builded or
is building. Here it nips off its wax by means of its
hind legs, which are furnished with a_ scissors-like ar-
rangement, and with its broad, trowel-like jaws moulds
it on the forming cells. Examine the ‘‘ wax-shears ’’ on
306 FIRST LESSONS IN ZOOLOGY

the hind most legs of a dead bee and also the trowel-like
jaws. Make drawings. Watch carefully the growth of
the new comb. Of what shape are the new cells? Are
they all of the same size? Is the bottom of each cell
flat? How are those of the two opposite layers of which
the comb is composed related to each other?

Note several bees standing in the covered entrance to
the hive and steadily and rapidly vibrating their wings.
They are ‘‘ ventilating ’’—that is, making currents of air
so that fresh air will constantly flow into the hive and
foul air out. Ventilating bees may also be seen scat-
tered through the hive. A movement of air through
the comb is necessary for the honey-making as well as for
ventilation. The nectar as it is gathered from flowers
and poured out into cells from the crops of the food-
gathering bees is too watery to be good honey, and must
be partly evaporated. The ventilation assists largely in
its evaporation. Touching the hand to the glass sides
note that the interior of the hive is warmer on a cold day
than the outer air. This is because the bees, when nec-
essary, buzz violently to make themselves unusually warm
and thus raise the temperature of the hive. When young
bees are being reared the hive must always be kept
warm. Note the bees clustering thickly over the brood-
cells, i.c., the cells containing young.

Can you note any difference in the appearance of the
various individuals? Are there some which do not
work? Are all the cells filled with honey or pollen? If
not, what is put into the other cells? The correct an-
swer to these questions brings us to the consideration of
the bees’ development or life-history, and the make-up of
the community. Some of the facts in the following brief
account can be readily observed by the pupils, but some
cannot. As many of the following statements as possible
should be confirmed by observation.
THE HONEY-BEE AND OTHER SOCIAL ANIMALS 3°7

A honey-bee community is made up of three kinds of in-
dividuals (fig. 243), namely, a single queen or mother which
lays the eggs from which all the other bees are produced,
several hundred drones or males, one of which becomes
the royal consort,
fertilizing the eggs,
and from ten to forty
thousand or more
workers, which do
all the work of the
community, gather-
ing food, making
wax, building comb,
ventilating the hive
and caring for the Fic. 243.—‘The honey-bee, Apzs mellifica;
young bees. The A, queen; &, drone; C, worker, (From

specimens. )
drones are larger,

 

more robust, and more hairy than the workers, while
the queen is longer, with a slender tapering abdomen.
Certain combs are chosen as brood-combs (fig. 244),
and beginning in the center of these and working out-
ward the queen lays a tiny white elongate egg in the
bottom of each cell. These eggs hatch in three days, and
the young bees or larve appear as white, soft, footless,
helpless, grubs. They are fed by certain worker bees
called nurses (workers which have not yet learned to go
out and gather pollen and honey), at first on a highly
nutritious substance called bee-jelly, which the nurses
make in their stomachs and regurgitate. After two or
three days of bee-jelly diet they are given pollen and
honey. A few days later a small mass of this new food
is put into each cell, which is then ‘‘ capped ’’ or covered
with wax. The larve after eating what is stored in their
cell change into pupz and lie quiescent for thirteen days
when they become fully developed bees. They now
308 FIRST LESSONS IN ZOOLOGY

gnaw the caps away and come out into the hive ready to
work.

Such is the life-history of the worker bee. It has been
demonstrated that the eggs which produce workers and
those which produce queens do not differ, but that if the
workers desire to have a queen they tear down two or
three cells around some one cell, enlarging it into a vase-
shaped cavity (fig. 244). The Jarva that hatches in this
large cell is fed for its whole larval life with rich bee-jelly.
From its pupa issues not a worker but a new queen. The

Se a A

ae

 

right end of upper row of cells and going to the left 1s a series of egg,

young larvee, old larvee, pupa, and adult ready to issue; the large

curving cells below are queen-cells, (From Benton.)
eggs which produce drones or males differ from those
which produce queens and workers in being unfertilized,
the queen having the power to lay either fertilized or
unfertilized eggs. When anew queen appears, or when
several appear at once, there is great excitement in the
community. If there are several they are believed to
fight among themselves until only one survives. It is
said that a qucen never uses its sting except against
another queen. The old queen now leaves the hive ac-
companied by many of the workers. She and her fol.
THE HONEY-BEE AND OTHER SOCIAL ANIMALS 3°9

lowers fly away together, finally alighting on some tree
branch and hanging there in a dense mass. This is the
familiar act of ‘‘swarming.’’ Scouts leave the swarm to
find a new home, to which they finally conduct the others.
Thus is founded a new colony.

There are many more interesting things to be learned
of the life in a honey-bee community; how it protects
itself from the dangers of starvation, when food is scarce
or winter comes on, by killing the useless drones and the
immature bees in egg and larval stages; how the instinct
of home-finding has been so highly developed that the
worker may go miles away for honey and nectar, flying
with unerring accuracy back to the hive; of the extraor-
dinarily nice structural modifications which adapt the
bee so perfectly for its complex and varied affairs; and of
the tireless persistence of the workers until they fall ex-
hausted and dying in the performance of their duties.
The community, it is important to note, is a persistent or
continuous one. The workers do not live long, the spring
broods usually not over two or three months, and the fall
broods not more than six or eight months; but new bees
are hatching while the old ones are dying, and the com-
munity as a whole always persists. The queen may live
several years, perhaps as many as five. She lays about
one million eggs a year.

The honey-bees offer a splendid example of mutual aid
instead of bitter war among individuals of a species. To
be sure there is competition among different honey-bee
communities for food, but among the thousands of indi-
viduals composing a single colony every one works for
the benefit of the whole great family; the workers devote
their whole life unceasingly for others.

Ants.—More than two thousand different kinds or spe-
cies of ants are known, and all of them live in large
communities or households and show a truly communal
3to FIRST LESSONS IN ZOOLOGY

life. Ants, like honey-bees, may be kept in the school-
room ina ‘‘ formicary,’’ and thus observed at home as well
as when foraging in the fields. A ‘‘formicary’’ is simply
an artificial nest in which an ant colony has been estab-
lished. Professor Comstock gives the following directions
for arranging a formicary:

‘« The principal materials needed for the construction
of a nest of this kind are two panes of window-glass ten
inches square, a sheet of tin eleven inches square, and a
piece of plank one and a fourth inches thick, twenty
inches long, and at least sixteen inches wide.

‘«To make the nest, proceed as follows: Cut a trian-
gular piece about one inch long on its two short sides
from one corner of one of the panes of glass. From the
sheet of tin make a tray three-eighths of an inch in depth.
This tray will be a little wider than the panes of glass
and will contain them easily. On the upper side of the
plank a short distance from the edge cut a deep furrow.
This plank is to form the base of the nest, and the furrow
is to serve as a moat, which is to be kept filled with
water in order to prevent the escape of the ants. It is
necessary to paint the base with several coats of paint to
protect it from water and thus prevent its warping.

‘«To prepare the nest for use, place the tin tray on the
base, put in the tray the square pane of glass, lay on the
edges of the glass four strips of wood about one-half inch
wide and a little thicker than the height of the ants which
are to be kept in the nest, cover the glass with a layer of
fine earth of the same thickness as the strips of wood,
place upon this layer of earth and the strips of wood the
pane of glass from which one corner has been cut, and
cover the whole with a cover of the same size and shape
as the upper pane of glass. In the nest figured the cover
is made of blackened tin, and one-half of it is covered
by a board. This gives a variation in temperature in
THE HONEY-BEE AND OTHER SOCIAL ANIMALS 311

different parts of the nest when it stands in the sun-
light.

‘« The ants when established in the nest are to mine in
the earth between the two plates of glass. The removal
of one corner from the upper pane provides an opening to
the nest. The thickness of the strips of wood between
the edges of the two panes of glass determines the depth
of the layer of earth in which the ants live. This should
not be much thicker than the ants are high; for if it is the
ants will be able to conceal themselves so that they can-
not be observed

‘““The nest being prepared the next step is to transfer
a colony of ants to it. The things needed with which to
do this are a two-quart glass fruit-can, or some similar
vessel that can be closed tightly, a clean vial, and a
garden trowel. With these in hand find a small colony
of ants, such as are common under stones in most parts
of the country. Collect as many of the ants and of the
eggs, larve, and pupz as possible, and put them in the
fruit-can, together with the dirt that is scooped up in col-
lecting them with the trowel. Search carefully for the
queen; sometimes she is found immediately beneath the
stone covering the nest, but often it is necessary to
dig a considerable distance in order to find her. She can
be recognized by her large size. If the queen is not
found, empty the contents of the can back into the nest,
and take up another colony; without a queen the experi-
ment will be a failure. When the queen is found place
her in the vial so that she shall not be injured while being
carried to the schoolroom.

‘«Having obtained a queen and a large part of her
family, old and young, return to the schoolroom and
empty the contents of the fruit-can on to the board cov-
ering the upper pane of glass, and place the queen there
with her family. If much dirt and rubbish has been col-
3t2 FIRST LESSONS IN ZOOLOGY

lected with the ants, remove some of it so that not more
than half a pint of it remains. When this is done leave
the ants undisturbed for a day or two. Of course the
moat should be filled with water so that they cannot
escape.

‘* Usually within twenty-four hours the ants will find
the opening leading into the space between the two panes
of glass and will make a mine into the layer of earth which
is there, and will remove their queen and young to this
place. This process can be hastened by gradually re-
moving the dirt placed on the cover of the nest with
ants.

‘« After the ants have made a nest between the panes
of glass they can be observed when desired by merely
lifting the board forming the cover of the nest.

‘* With proper care a colony can be kept in a nest of
this kind as long as the queen lives, which may be sev-
eral years. The food for the ants can be placed on the
base of the nest anywhere within the moat, and may
consist of sugar, minute bits of meat, fruits, etc. With
a little care the kinds of food preferred by the colony can
be easily determined. The pupz of ants, which can be
collected from nests in the field during the summer months
will be greedily devoured. The soil in the nest should
be kept from becoming too dry by putting a little water
into one side of the tin tray from time to time.

The ant workers are specially distinguished in structure

”

from the males and females by their lack of wings (fig.
245), and in numerous species there are two sizes or kinds,
known as worker majors and worker minors. The life-
history and communal habits of ants are not so thoroughly
known as are those of the honcy-bee, but they show even
more remarkable specializations. The ant nest or for-
micary is, with most species, an claborate system of
underground galleries and chambers, special rooms beine-
THE HONEY-BEE AND OTHER SOCIAL ANIMALS 313

used exclusively for certain special purposes, as nurse-
rooms, food-storage rooms, etc. The food of ants com-
prises many animal and vegetable substances, but the
favorite kind with many species is the ‘‘ honey-dew
secreted by the plant-lice (Aphididz) and scale insects

”

 

Fic. 245.—The little black ant, Monomorium minutum, a, female; 6, female
with wings; ¢, male; d, workers; e, pupa; /, larva; g, egg of worker,
all enlarged. (From Marlatt.)

(Coccide). To obtain this honey-dew an ant strokes one

of the aphids with its antenne, when the fluid is excreted

by the little insect and drunk by the ant. In order to
have a certain supply of this food some species of ants
care for and defend these defenseless aphids, which have
been called their ‘‘cattle.’’ In some cases they are even
taken into the ants’ nest and provided with food. In the
Mississippi Valley a certain kind of plant-louse lives on
314 FIRST LESSONS IN ZOOLOGY

the roots of corn. Its eggs are deposited in the ground
in the autumn and hatch the following spring before the
corn is planted. The common little brown ant also lives
abundantly in the corn-fields, and is especially fond of the
honey-dew secreted by the corn-root lice. So when they
hatch in the spring before there are corn-roots for them
to feed on, the ants with great solicitude carefully place
them on the roots of a certain kind of knot-weed which
grows in the field and there protect them until the corn
germinates. They are then removed to the roots of the
corn. In the arid lands of New Mexico and Arizona the
ants rear scale insects on the roots of cactus.

Ants are among the most warlike of insects. Battles
between communities of different species are numerous,
the victorious community taking possession of the food-
stores of the conquered. Some species of ants live wholly
by war and robbery. In the case of the remarkable
robber-ant (Eciton), found in tropical and sub-tropical
regions, most of the workers are soldiers, and no longer
do any work but fighting. The whole community lives
exclusively by pillage. Some kinds go even farther than
mere robbery of food-stores; they make slaves of the
conquered ants. There are numerous species of these
slave-making ants. They attack a nest of another species
and carry home the eggs and larve and pupz of the con-
quered community. When these come to maturity they
have to act as slaves, collecting food, building additions
to the nest, and caring for the young of the victors.

As in tne case of the honey-bee the larval ants are
helpless grubs and are cared for and fed by nurses. The
so-called ‘‘ants’ eggs ’’—-the little white oval masses
which we often see being carried in the mouths of ants in
and out of nest—are not eggs, but are the pupa, which
are being brought out to enjoy the warmth and light of
the sun or being taken back into the nest afterward.
THE HONEY-BEE AND OTHER SOCIAL ANIMALS 315

Careful observation of the ants

in the indoor nest,

and of nests and individuals out of doors, will reveal

many of the remarkable and in-
teresting features of ant life, and
almost surely things not now known
to naturalists will be found out.
Wasps and bumble-bees.—The
true wasps, commonly called yellow-
jackets and hornets, and the bum-
ble-bees, also live in communities;
but among these forms each house-
hold lasts only from spring into
autumn, new communities being
formed the next spring by queens
which live through the winter. The
few bumble-bees which we see in
winter-time, usually hiding in some
sheltered place, are queens. In the
spring each queen finds a deserted
mouse’s nest or other hole in the
ground, gathers a mass of pollen,

 

Fic. 246.—Bumble-bee at
clover blossom. (From
life.)

and lays some eggs on it. The larve, hatching, feed
on the pollen, dig out irregular cells for themselves in
it, pupate, and soon issue as workers or unfertile females.

 

Fic, 247.—Yellow-jackets, (Natural
size; from life. )

These workers gather more
pollen, the queen lays more
eggs, and several succes-
sive broods of workers are
produced. Finally, late in
the summer a brood con-
taining males (drones) and
fertile females (queens) is
produced, mating takes

place, and then before winter all the workers and drones
and some of the queens die, leaving a few fertilized
316 FIRST LESSONS IN ZOOLOGY

queens to hibernate and establish new communities in
the spring.

The yellow-jackets (fig. 247) and hornets ( Vespida), the
so-called social wasps, have a life-history very like that of
the bumble-bees. The communities of the social wasps
are larger and their nests are often made above ground,

 

Tic. 248.—Nest of yellow-jackets (Vespa) cut open to show combs within.
(About one-third natural size; photograph from specimen. )

being composed of several combs, one above the other,
and all inclosed in a many-Jayered covering sac open
only by a small hole at the bottom (fig. 248). This kind
of nest hangs from the branch of a tree and is built of
Wasp-paper, which is a pulp made from bits of old wood
chewed by the workers. The brood-cells are provisioned
with killed and chewed insects, the larva: of both soli-
tary and social wasps living on animal food, while the
larvee of both solitary and social bees are fed on flower-
pollen and honey. As with the bumble-bees, all the
THE HONEY-BEE AND OTHER SOCIAL ANIMALS 317

members of the community except a few fertilized females
die in the autumn, the surviving queens founding new

coionies in the spring. The queen then builds a minia-_
ture ‘‘hornet’s nest’’ (fig. 249), lays an egg in each cell,
and stores the cells with chewed insects. The first brood

is composed of workers, which enlarge the nest, get
more food, and relieve the queen of all labor except that
of egg-laying. More broods of workers follow until the

 

Fic. 249.—Queen-nest of yellow-jacket (Vespa). Specimen at right in
normal condition; at left cut open to show brood-cells. (Natural size;
from specimen.)

fall brood of males and females appears, after which the
origina] process is repeated.

The nests of both bumble-bees and hornets are familiar
to all country children, and in summer may be readily
found and observed. In early spring the small ‘‘queen-
nests’’ of hornets should be looked for, and in winter the
hibernating queen bumble-bees and wasps should be
sought under stones, in crevices of bark, or in other
sheltered places.
318 FIRST LESSONS IN ZOOLOGY

Other social animals.—-Besides bees, ants, and wasps
there are many other animals which live together in
more or less helpful association with each other. The
beavers, which unite to build a dam in order to make a
pond in which to build their houses; the prairie-dogs,
which live in large ‘‘towns’’; the bands of crows that
post sentinels to watch for enemies while the others
feed; the birds which migrate in great flocks following a
few leaders; and the wolves, which hunt together in bands
and are thus able to attack and pull down animals too
large to be overcome by a single individual, are all
examples of animals which display a certain degree of
mutual aid. Let each pupil try to discover others among
the animals familiar to him.

For detailed accounts of the honey-bee see Cowan's
‘« Natural History of the Honey-bee,’’ or Cook's ‘‘ Bee-
keepers’ Guide,’’ or Cheshire’s ‘‘ Bees and Bee-keeping.”’
Maeterlinck’s ‘‘ The Life of a Bee’’ is most interesting.
For a good account of the wasps and hornets see Orme-
rod's ‘‘ British Social Wasps.’’ ‘‘ Ants and their Ways,”’
by W. F. White, is good. For an interesting account of
experiments to reveal the intelligence of ants, bees, and
wasps, see Lubbock’s ‘‘ Ants, Bees, and Wasps.’’ W. M.
Wheeler has published in various numbers of the ‘* Ameri-
can Naturalist ’’ of 1902 accounts of his interesting studies
on ants.

 
CHAPTER XXI

HOW ANIMALS ARE DISTRIBUTED OVER
THE WORLD

Animals limited to particular regions.—_We are used
to seeing certain kinds of animals, such as rabbits, robins,
field-mice, and garter-snakes in the particular region in
which we live, and never seeing others, such as lions,
elephants, birds-of-paradise, and boa-constrictors. We
know, indeed, that these latter kinds do not live in our
region nor even on our continent. But we are too likely
to take such things for granted, and not inquire why it is
that only certain particular kinds live in North America
and certain others in Africa, while others still may be
found all over the world.

As a matter of fact there are few things about animals
more interesting to observe than their distribution over
the world. Unfortunately in this matter we must depend
for many of our facts upon the statements of other people;
we can observe at first hand only a few of them. We
can see for ourselves what kinds of animals live in our
neighborhood, and that certain other kinds with which
we are somewhat familiar from menageries or books do
not. We can see that some animals, fishes for example,
live always in water; and that some water animals live
always in ponds, while others prefer the brooks. Many
other water animals, on the contrary, can live only in
the ocean (see Chapter X, on ocean animals), and of
these some always keep near the bottom, where it is dark

319
320 FIRST LESSONS IN ZOOLOGY

and cold, while many live on or near the surface. Again,
some of the surface forms keep always near the shore,
while others never or rarely come in sight of land. But
most of the familiar animals about us cannot live in water

 

 

 

 

 

Vic. 250.—The Parnassian butterfly (Parnassius smintheus) which lives in
the Rocky Mountains and Sierra Nevada, at an altitude of 5000 feet
and above. (Natural size; from specimen.)

at all. They either burrow in the ground like moles and
gophers, or live in trees like squirrels, or fly in the air
like birds and butterflies.

Barriers.—Of land animals some can live only in
tropical and sub-tropical regions, as the monkeys and
most of the parrots, some live only in the snowy regions
near the poles, as the polar bear and great walrus, while
many prefer neither of these extremes but live in the
temperate zones. Although the word ‘' prefer ’’ has been
used, it is usually true that animals which live in arctic
regions are not able to live elsewhere; they seem to be
adapted solely for an arctic climate, so that the line around
the earth south of which there is frost and freezing weather
during a part of the year only is a sort of barrier beyond
which they cannot safely venture. And, turning to the
HOW ANIMALS ARE DISTRIBUTED OVER THE WORLD 321

animals of the tropics, we find that most of them can-
not endure any frost or freezing at all, the southernmost
line of frost being to them a barrier north of which they
cannot live. These barriers are raised by temperature.
Similarly there are barriers made by differences in rain-
fall. The animals of the Eastern United States, accus-
tomed to a large amount of moisture and to luxuriant
vegetation, could not live on the arid, burning, sterile
desert; but the lizards and desert rats and coyotes live
there successfully.

But barriers more marked and more tangible are those
such as oceans which surround continents and islands and
thus limit the land animals of these regions to their re-
spective districts. Similarly the land which surrounds a
lake or pond limits the fishes in it to that particular lake
or pond, although they would live quite as well in some
other. And it is true that many animals could live else-
where than in the place to which they are now restricted
if they could only get there. Indeed they could live in
any other region where the climate and general conditions
are like their present home. So we say that the distri-
bution of animals over the world is largely determined by
barriers—barriers of temperature, of moisture, of water,
of land, of high mountains, of deserts, of anything that
the animal cannot cross.

How animals spread.—The ways in which animals
spread are mostly easily understood. Birds can fly to new
regions; quadrupeds can travel on foot for long distances ;
fishes can swim from one part of a river or lake or ocean
to another. But although two rivers may empty into the
ocean close together fishes cannot often easily get from
one into the other. For most fresh-water fishes cannot
live in salt water, so that even a small stretch of ocean
is an effective barrier to them. Salmon, some eels, and
a few other fishes, however, live part of the time in the
322 FIRST LESSONS IN ZOOLOGY

ocean and part in streams. Many animals are trans-
ported long distances involuntarily. Rats and mice in-
vading a ship from wharves at Liverpool sometimes get
carried across the Atlantic Ocean to America. In fact
the common black rats and brown rats of the houses and
barns over this whole country are not native rats at all,
but are descendants of European rats. unintentionally
brought across the ocean in ships. The same is true of
many of the insect pests which trouble us; for example,
the Hessian fly, which does great damage to wheat, the
cockroaches of our houses and the carpet beetles or buffalo
bugs which attack rugs and carpets. Sometimes a boring
insect lying snugly in a log gets carried down a river,
out into the ocean, and by means of ocean currents far
away to some island where it may crawl out and lay eggs
and so establish itself in a new country. Sometimes
animals are intentionally imported by man from foreign
countries. The introduction of the English sparrow into
this country and the rabbits into Australia are examples
of unfortunate experiments along this line.

Map showing the distribution of animals.—Zoologists
have been studying the distribution of animals so long
that they have been able to map out the range of many
of the well-known kinds. On a map of the world they
indicate, by shading, all those regions in which lions
exist; all those in which elephants live, and all those in
which humming-birds are found. Now this kind of map-
making reveals many things of interest and throws much
light on the relations of animals to climate, to geography,
and to each other.

Such zoological map-making may be restricted to a
limited locality, and is the best way for beginning stu-
dents to study distribution. On a large sheet of strong
paper a map of the region about the schoolhouse, say one
or two miles square, should be made, with all the streams,
HOW ANIMALS ARE DISTRIBUTED OVER THE WORLD 323

ponds, swamps, pastures, woods, etc. Then search
carefully for the haunts of certain kinds of animals which
are known to occur in the mapped region, and mark them
on the map. It will soon be found that the different
kinds of animals are more or less limited to certain parts
of the region. Attempt may next be made to find out
why. Are there barriers ? Ifso, of what nature? They
cannot well be barriers of temperature or climate, unless
a mountain is included in the region, but may be con-
cerned with food, suitable hiding-places, proximity to
man, necessity of water for breeding in, etc. This is a
study, all of which must be made in the field, and where
much ingenuity in observing and reasoning must be used.

For a reference-book on the subject of this chapter
see Heilprin’s the ‘‘ Distribution of Animals,’’ or Bed-
dard’s ‘* Zoo-geography.”’
APPENDIX |

NOTE-BOOKS, DRAWINGS, AND REFERENCE
BOOKS.

Note-books and drawings.—Each pupil should have
a note-book of about 8 x I0 inches, opening at the end,
in which both drawings and notes can be made. The
paper should be unruled and of good quality (not too
soft). Each pupil should make the drawings called for
in connection with the study of the various animals con-
sidered in this book. These drawings should be in out-
line, and put in by pencil; the lines may be inked over
if preferred. Each drawing and all the animal parts rep-
resented in it should be fully named. Notes should be
made of any observations which cannot be represented
in the drawings, for example, on the behavior of living
animals. All notes referring to matters of life-history
should be dated.

Scattered through this book will be found numerous
suggestions for student field-work, for the observation of
the life-history and habits and conditions of animals in
nature. The initiation and direction of such work is left
to the teacher. But its importance, both because of its
instructiveness and its interest is great. Pupils should
not only be incited to make individual observations
whenever and wherever they can, but the teacher should
make little field-excursions with the class, or with parts of
it, at various times, to ponds cr streams or woods, and
‘‘show things’’ to all. The life-history and feeding-
habits of insects, the web-making of spiders, the flight,

325
326 APPENDIX I

songs, nesting and care of young of birds, the haunts of
fishes, the development of frogs, toads, and salamanders,
the home-building and feeding-habits of squirrels, mice,
and other familiar mammals are all (as has been called
attention to at proper places in the book) specially fit
subjects for field-observation.

Each pupil should keep a field note-book, recording
from day to day, under exact date, any observations he
may make. Let the most trivial things be noted; when
referred to later in connection with other notes they may
not seem so trivial. The field note-book should be
smaller than the laboratory note- and drawing-book,
small enough to be carried in the pocket. Notes should
be made on the spot of observation ; do not wait to get
home. Sketches, even rough ones, may be advanta-
geously put into the book. Students with photographic
cameras can do some very interesting and valuable field-
work in making photographs of animals, their nests and
favorite haunts. Such photographic work is very effec-
tively used now in the illustration of books about animals
and plants (see the reproductions of photographs in this
book). Ifthe class is making a collection the collecting
notes or data made in the field-books of the different
pupil collectors should all be transferred to a common
‘“Notes on Collections ’’ book kept by the whole class.

Reference-books.— Throughout the preceding chapters
exact references have been made to various books, as
many of which as possible should be kept in the school
library. Some of these references have been made with
special regard to the teacher, but most with special
regard to the pupil. All of the books referred to are in-
cluded in the following list. For the convenience of the
prospective buyer the names of the publishers and prices
of the books are appended. In buying books it is, of
course, not necessary to order from the various publishers.
REFERENCE BOOKS 327

A list of books desired may be handed to any book-
dealer, who will order them, and who should in most cases
be able to get them for a little less than publisher’s list
prices.

Bailey, Florence M. Handbook of Birds of the Western United States. 1902.
Houghton, Mifflin & Co. $3.50.

Baskett, J. N. Story of the Fishes. D. Appleton & Co. $0,6s5.

—— The Story of the Birds. 1899. D. Appleton & Co. $0.65.

Beard, J. C. Curious Homes and their Tenants. D. Appleton & Co. $0.65.

Beddard, Frank. Animal Coloration. 1892. Macmillan Co. $3.50

—— Zoogeography. 1895. Macmillan Co. $1.60.

Bendire, Chas. Directions for Collecting, Preparing, and Preserving Birds
Eggs and Nests. Distributed by the U. S. National Museum.

Bird-lore, an Illustrated Journal about Birds. Macmillan Co. $1.00 a
year.

Chapman, Frank M. Handbook of the Birds of Eastern North America,
1899. TD. Appleton & Co. $3.00.

—— Bird-life. 1900. D, Appleton & Co. $2.00

Cheshire, F. R. Bees and Bee-keeping. 1886. L. Upcott Gill.

Comstock, J. H. Manual for the Study of Insects. 1897, Comstock
Publishing Co. $3.75.

—— Insect Life. 1901. D. Appleton & Co. $1.50.

— and Kellogg, V.L. Elements of Insect Anatomy. 1901. Comstock
Publishing Co. $1.00.

Cooke, W. W. Bird Migration in the Mississippi Valley. Distributed by
the Division of Biological Survey, U. S. Dept. Agric.

Coues, Elliott. Key to North American Birds. 1890. Estes & Lauriat.
$7.50.

Cowan, T. W. Natural History of the Honey-bee, 1890. London:
Houlston. 1s. 6d.

Davie, Oliver. Methods in the Art of Taxidermy. 1894. Columbus, O.
Oliver Davie & Co. $10.00 ze?.

Dickerson, Mary C. Moths and Butterflies. 1901. Ginn & Co. $1.50.

Dugmore, A. R. Bird Homes, Doubleday, Page & Co. $2.00,

Eckstrom, F. H. The Woodpeckers. Houghton, Mifflin & Co. $1.00,

Emerton, J. H. Spiders, their Structure and Habits, 1890. Knight E.
Millet. $1.50 vet.

—— Common Spiders. 1902. Ginn & Co.

Fabre, J. H. Insect Life. 1901. Macmillan & Co, $1.75.

Gage, S. H. Life History of the Toad. Teacher’s Leaflets, No. 9, April,
1898. Prepared by College of Agriculture, Cornell University, Ithaca,
N. Y.

Heilprin, A. The Distribution of Animals. 1886. D. Appleton & Co,
$2.00.
328 APPENDIX 1

Holland, Ww. J. The Butterfly Book. 1899. Doubleday & McClure Co.
$3.00.

Hornaday, W. T. Taxidermy and Zoological Collecting. 1897. Chas.
Scribner’s Sons. $2.50 wet.

Howard, L. 0. Mosquitoes. £901. McClure, Phillips & Co. $1.50 met.

—— The Insect Book. 1901. Doubleday, Page & Co, $3.00 vet,

Huxley, T. H. The Crayfish; an Introduction to the Study of Zoology.
D. Appleton & Co. $1.75.

Jordan, D. S. Manual of Vertebrate Animals of the Northern United States.
8th ed. 1899. A.C, McClurg & Co. $2.50,

-—— and Evermann, B. W. [ood and Game Fishes of North America,
1902. Doubleday, Page & Co. $3.00 vet,

—— and Kellogg, V. L. Animal Life. 1900, D, Appleton & Co, $1.20.

Kellogg, V.L. Elementary Zoology. Ig01. Henry Holt & Co. $1.20.

Long, Wm. J) Ways of Wood Folk. rg0r, Ginn & Co, $0.65.

—— Wilderness Ways. 1901, Ginn & Co. $0.65.

Secrets of the Woods. 1901, Ginn & Co. $0.65.

Lubbock, John. Ants, Bees, and Wasps. 1882, D. Appleton & Co. $2.00.

Maeterlinck, Maurice. The Life ofa Bee. I902. Dodd, Mead & Co.

McCarthy, Eugene. Familiar Fish. D. Appleton & Co. $1.50.

McCook, Henry. American Spiders and their Spinning Work. 3 vols.
1889-1893. HL. C. McCook, Phila., Pa. $30.00.

Miall, L.C. The Natural History of Aquatic Insects. 1895. Macmillan
Co, $1.75.

Needham, J. B. Outdoor Studies. 1898. American Book Co. $0.40.

Newbigin, M. I. Color in Nature. 1898. London: John Murray.

Ormerod, E. L. British Social Wasps. 1868. Longmans, Green, & Co.,
Reader, and Dyer.

Parker, T. J. Lessons in Elementary Biology. 1897. Macmillan Co.
$2.65.

Peckham, George W. and E. J. On the Instincts and Habits of the Soli-
tary Wasps. 1898. Sold by Des Forges & Co., Milwaukee, Wis. $2.00.

Poulton, E. B. The Colors of Animals. 1890. D. Appleton & Co. $1.75.

Ridgway, R. Directions for Collecting Birds. Distributed by U. S. Na-
tional Muscum.

Scudder, S.H. The Life of a Butterfly. 1893. Henry Holt & Co. $1.00,

—— Everyday Butterflies. 1899. TToughton, Mifflin & Co. $2.00,

Van Beneden, E. Animal Parasites and Messmates, 1876. 1D, Appleton
& Co, $1.50.

White, W.F. Ants and their Ways, 1895. The Religious Tract Society.

 
APPENDIX II

REARING ANIMALS AND MAKING COLLEC-
TIONS

MucH good work in observing the behavior and life-
history of some kinds of animals can be done by keeping
them alive in the schoolroom under conditions simulating
those to which they are exposed in nature. The growth
and development of frogs and toads from egg to adult, as
well as their feeding habits and general behavior, can all
be observed in the schoolroom as explained in Chapter
II. Harmless snakes are easily kept in glass-c vered
boxes; snails and slugs are contented dwellers indoors;
certain fish live well in small aquaria, and many other
familiar forms can be kept alive under observation for a
longer or shorter time. But from the ease with which
they are obtained and cared for, the rapidity of their
growth, the inexpensiveness of their live-cages, and the
interesting character of their life-history and general habits,
insects are, of all animals, the ones which specially com-
mend themselves from the schoolroom menagerie. In
the notes in chapter XII are numerous suggestions re-
garding the obtaining and care of certain kinds of insects
which may be reared and studied to advantage in the
schoolroom. In the following paragraphs are given direc-
tions for making the necessary live-cages and aquaria for
these insects.

Live-cages and aquaria.—Prof. J. H. Comstock has
so well described the making of simple and inexpensive

329
330 APPENDIX Il

cages and aquaria in his book, ‘‘ Insect Life,’’ that, with
his permission, his account is quoted here.
Live-cages.—‘' A good home-made cage can be built
by fitting a pane of glass into one side of an empty soap-
box. <A board, three or
four inches wide, should
be fastened below the
glass so as to admit of a
layer of soil being placed
in the lower part of the
cage, and the glass can
be made to slide, so as to
serve asa door (fig. 251).

 

The glass should fit close-

s =

Fic. 251.—Soap-box breeding-cage for ly when shut, to prevent
insects. (From Jenkins and Kellogg.)

the escape of the insects.

‘(In rearing caterpillars and other leaf-eating larvae,
branches of the food-plant should be stuck into bottles or
cans which are filled with sand saturated with water. By
keeping the sand wet the plants can be kept fresh longer
than in water alone, and the danger of the larve being
drowned is avoided by the use of sand.

‘Many larve when full-grown enter the ground to
pass the pupal state; on this account a layer of loose soil
should be kept in the bottom of a breeding-cage. This
soil should not be allowed to become dry, neither should
it be soaked with water. If the soil is too dry the pupe
will not mature, or if they do so the wings will not expand
fully; if the soil is too damp the pupz are liable to be
drowned or to be killed by mold.

‘It is often necessary to keep pupa over winter, for a
large proportion of insects pass the winter in the pupal
state. Hibernating pupz may be left in the breeding-
cages or removed and packed in moss in small boxes.
Great care should be taken to keep moist the soil in the
REARING ANIMALS AND MAKING COLLECTIONS 331

breeding-cages, or the moss if that be used. The cages
or boxes containing the pupz should be stored in a cool
cellar, or in an unheated room, or in a large box placed
out of doors where the sun cannot strike it. Low tem-
perature is not so much to be
feared as great and frequent
changes of temperature.

‘‘Hibernating pupz can be
kept ina warm room if care be
taken to keep them moist, but
under such treatment the mature
insects are apt to emerge in
midwinter.

‘‘An excellent breeding-cage
is represented by fig. 252. It
is made by combining a flower-
pot and a lantern-globe. When
practicable, the food-plant of
the insects to be bred is planted

 

é Fic. 252. — Lamp-chimney and
in the flower-pot; inother cases  flower-pot breeding-cage for

a bottle or tin can filled with ae (From Jenkins and
ellogg.)

wet sand is sunk into the soil
in the flower-pot, and the stems of the plant are stuck into
this wet sand. The top of the lantern-globe is covered
with Swiss muslin. These breeding-cages are inexpen-
sive, and especially so when the pots and globes are
bought in considerable quantities. A modification of this
style of breeding-cage that is used by the writer differs
only in that large glass cylinders take the place of the
lantern-globes. These cylinders were made especially
for us by a manufacturer of glass, and cost from six to
eight dollars per dozen, according to size, when made in
lots of fifty.

‘When the transformation of small insects or of a small
number of larger ones are to be studied, a convenient
332 APPENDIX II

cage can be made by combining a large lamp-chimney
with a small flower-pot.

‘« The root-cage.—¥or the study of insects that infest
the roots of plants, the writer has devised a special form
of breeding-cage known as the root-cage. In its simplest
form this cage consists of a frame holding two plates of
glass in a vertical position and only a short distance apart-
The space between the plates of glass is filled with soil in
which seeds are planted or small plants set. The width
of the space between the plates of glass depends on the
width of two strips of wood placed between them, one at
each end, and should be only wide enough to allow the
insects under observation to move freely through the soil.
If it is too wide the insects will be able to conceal them-
selves. Immediately outside of each glass there is a piece
of blackened zinc which slips into grooves in the ends of
the cage, and which can be easily removed when it is
desired to observe the insects in the soil.

‘(A quarta.—For the breeding of aquatic insects aquaria
are needed. As the ordinary rectangular aquaria are
expensive and are liable to leak we use glass vessels
instead.

‘Small aquaria can be made of jelly-tumblers, glass
finger-bowls, and glass fruit-cans, and larger aquaria can
be obtained of dealers. A good substitute for these is
what is known as a battery-jar (fig. 253). There are
several sizes of these, which can be obtained of most
dealers in scientific apparatus.

‘“To prepare an aquarium, place in the jar a layer of
sand; plant some water-plants in this sand, cover the sand
with a layer of gravel or small stones, and then add the
required amount of water carefully, so as not to disturb
the plants or to roil the water unduly. The growing
plants will keep the water in good condition for aquatic
animal life, and render changing of the water unnecessary,
REARING ANIMALS AND MAKING COLLECTIONS — 333

if the animals in it live naturally in quiet water. Among
the more available plants for use in aquaria are the fol-
lowing:

‘““Waterweed, -lodea canadensis.

‘‘ Bladderwort, Utrzcularza (several species).

««Water-starwort, Calltriche (several species).

“Watercress, Masturtium officinale.

‘“«Stoneworts, Chara and WNitella (several species of
each).

‘«Frog-spittle or water-silk; Spzrogyra.

«« A small quantity of duckweed, Lemna, placed on the
surface of the water adds to the beauty of an aquarium.

 

  

Fic. 253. —Battery-jar aquarium. (From Jenkins and Kellogg.)

«When it is necessary to add water to an aquarium on
account of loss by evaporation, rain water should be used
to prevent an undue accumulation of the mineral-water
held in solution in other water.’’

Making collections.—Much is to be learned about
animals by ‘‘collecting’’ them. But the collecting
334 APPENDIX IL

should be done chiefly with the idea of learning about the
animals rather than with the notion of getting as many
specimens as possible. To collect, it is necessary to find
the animals alive; one learns thus their haunts, their local
distribution, and something of their habits, while by con-
tinued work one comes to know how many and what
different kinds or species of each group being collected
occur in the region collected over. Collecting requires
the sacrifice of life, however, and this will always be kept
well in mind by the humane teacher and pupil. Where
one set of specimens will do, no more should be col-
lected. The author believes that school work in this line
should be almost exclusively limited to the building up
of a common school collection. Let a single set of speci-
mens be brought together by the combined efforts of all
the members of the class, and let it be well housed and
cared for permanently. Each succeeding class will add
to it; it may come in time to be a really representative
exhibition of the local fauna.

The school collection should include not only adult
specimens of the various kinds of animals, forming a
systematic collection, as it is called, but also all kinds
of specimens which illustrate the structure and habits of
the animals in question and which will constitute a
so-called biological collection. Specimens of the eggs
and all immature stages; dissections preserved in alcohol
or formalin showing the external and internal anatomy;
nests, cocoons, and all specimens showing the work and
industries of the various animals; in short, any specimen
of the animal itself in embryonic or postembryonic con-
dition, or any parts of the animal, or anything illustrating
what the animal does or how it lives, all these should be
collected as assiduously as the adult individuals. Each
specimen in the collection should be labelled with the
name of the animal, the date, and locality, and the name
REARING ANIMALS AND MAKING COLLECTIONS 335

of the collector, with any particular information which
will make it more instructive. If such special data are
too voluminous for a label, they should be written in a
general note-book called ‘‘ Notes on Collections ’’ (kept
in the schoolroom with the collection), the specimen and
corresponding data being given a common number so that
their association may be recognized. In the following
paragraphs are given brief directions for catching, pinning
up, and caring for insects,
for making skins of birds
and mammals, and _ for
the alcoholic preservation
of other kinds of animals.

Insects. —For catching
insects there are needed
a net, a killing-bottle, a
few small vials of alcohol,
and a few small boxes to
carry home live  speci-
mens, cocoons, galls, etc.
For preparing and pre-
serving the insects there
are needed insect-pins,
cork- or pith-lined drawers

 

Fic. 251 —Insect killing-bottle; cyanide

or boxes, and small wide- of potassium at bottom, covered with
mouthed bottles of alco- plaster of Paris. (From Jenkins and
hol Kellogg.)

The net, about 2 feet deep, tapering and rounded at
its lower end, is made of cheesecloth or bobinet (not
mosquito-netting, which is too frail), attached to a ring, one
foot in diameter, of No. 3 galvanized iron wire, which in
turn is fitted into a light wooden or cane handle about
three and a half feet long.

The killing-bottle (fig. 254) is prepared by putting a few
small lumps (about a teaspoonful) of cyanide of potassium
336 APPENDIX Il

into the bottom of a wide-mouthed bottle holding about
four ounces, and covering this cyanide with wet plaster of
Paris. When the plaster sets it will hold the cyanide in
place, and allow the fumes given off by its gradual
volatilization to fill the bottle. Insects dropped into
it will be killed in from two or three to ten minutes.
Keep a little tissue paper in the bottle to soak up moisture
and to prevent the specimens from rubbing. Also keep
the bottle well corked. Label it ‘‘ Poison,’’ and do not
breathe the fumes (hydrocyanic gas). Insects may be left
in it over night without injury to them.

Butterflies or dragon-flies too large to drop into the
killing-bottle may be killed by dropping a little chloro-
form or benzine on a piece of cotton, to be placed ina
tight box with them. Larve (caterpillars, grubs, etc.)
and pupz (chrysalids) should be dropped into the vials of
alcohol.

In collecting, visit flowers, sweep the net back and
forth over the small flowers and grasses of meadows and
pastures, look under stones, break up old logs and stumps,
poke about decaying matter, jar and shake small trees
and shrubs, and visit ponds and streams. Many insects
can be collected in summer at night about electric lights,
or a lamp by an open window.

When the insects are brought home or to the school-
room they must be ‘‘ pinned up.”’ Buy insect-pins,
long, slender, small-headed, sharp-pointed pins, of a
dealer in naturalists’ supplies. These pins cost ten
cents a hundred. Order Klaeger pins, No. 3, or Carls-
baeder pins, No. 5. These are the most useful sizes.
For larger pins order Klacger No. 5 (Carlsbaeder No. 8);
for smaller order Klacger No. 1 (Carlsbaeder No. 2).
Pin each insect straight down through the thorax (fig. 255)
(except beetles, which pin through the right wing-cover
near the middle of the body). On each pin below the
REARING ANIMALS AND MAKING COLLECTIONS 337

insect place asmall label with date and locality of capture.
Insects too small to be pinned may be gummed on to
small slips of cardboard, which should be then pinned up.
Keep the insects in drawers or boxes lined on the bottom
with a thin layer of cork, or pith of some kind. (Corn-
pith can be used; also in the West, the pith of the flower-
ing stalk of the century plant.) The cheapest insect-
boxes and very good ones, too, are cigar-boxes. But

 

Fic, 255.-—Insect aioe ‘pinned up.” (From Jenkins and Kellogg.)

unless well looked after they let in tiny live insects which
feed on the deadspecimens. Fora permanent collection,
therefore, it will be necessary to have made some tight
boxes or drawers. Glass-topped ones are best, so that
the specimens may be examined without opening them.
A ‘‘moth-ball’’ (naphthaline) fastened in one corner of
the box will help keep out the marauding insects.
Butterflies, dragon-flies, and other larger and beautiful-
winged insects should be ‘‘spread,’’ that is, should be
allowed to dry with wings expanded. To do this spread-
ing- or setting-boards (figs. 256 and 257) are necessary.
Such a board consists of two strips of wood fastened a short
distance apart so as to leave between them a groove for
the body of the insect, and upon which the wings are held
in position until the insect is dry. A narrow strip of pith
or cork should be fastened to the lower side of the two
338

strips of wood, closing the groove below.
is thrust the pin on which the insect is mounted.

APPENDIX II

Into this cork
An-

other strip of wood is fastened to the lower sides of the

cleats to which the two strips are nailed.

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Fic. 256. —Setting-board with butter-
(After Life,’

flies properly ‘spread.’
Comstock. )

birds, shooting is chiefly to be relied on.
(the smallest shot made) in small loads.

This serves
as a bottom and protects
the points of the pins which
project through the piece of
cork. The wings are held
down, after having been out-
spread with the hinder mar-
gins of the fore wings about
at right angles to the body,
by strips of paper pinned
down over them.

‘« Soft specimens ’’ such as
insect larve, myriapods, and
spiders should be preserved
in bottles of alcohol (85 per
cent). Nests, galls, stems,
and leaves partly eaten by
insects, and other dry speci-
mens can be kept in small
pasteboard boxes.

For a good and full ac-
count of insect-collecting and
preserving, with directions
for making insect-cases, etc.,

see Comistotk’s “* Tnsect
* pp. 284-314.
Birds. —I1n collecting

Use dust-shot
For shooting

small birds it is extremely desirable to have an auxiliary

barrel of much smaller bore than the usual shotgun which

can be fitted into one of the regular gun-barrels.

In such
REARING ANIMALS AND MAKING COLLECTIONS 339

an auxiliary barrel use 32-calibre shells loaded with dust-
shot instead of bullets. Plug up the throat and vent of
shot birds with cotton, and thrust each bird head down-
ward into a cornucopia of paper. This will keep the
feathers unsoiled and smooth.

Birds should be skinned soon after bringing home, after
they have become relaxed, but before evidences of decom-
position are manifest. The tools and materials necessary
to make skins are scalpel, strong sharp-pointed scissors,

 

Fic. 257.—Setting-board in cross-section to show construction. (After
Comstock, )

bone-cutters, forceps, corn-meal, a mixture of two parts
white arsenic and one part powdered alum, cotton, and
metric-system measure. Before skinning, the bird should
be measured. With a metric-system measure carefully
take the alar extent, i.e. spread from tip to tip of out-
stretched wings; length of wing, i.e. length from wrist-
joint to tip; length of bill in straight line from base (on
dorsal aspect) to tip; length of tarsus, and length of
middle toe and claw.

To skin the bird, cut from anus to point of breast-bone
through the skin only. Work skin away on each side to
legs; push each leg up, cut off at knee-joint, skin down
to next joint, remove all flesh from bone, and pull leg
back into place; loosen skin at base of tail, cut through
yertebral column at last joint, being careful not to cut
340 APPENDIX II

through bases of tail-feathers; work skin forward, turning
it inside out, loosening it carefully all around, without
stretching, to wings; cut off wings at elbow-joint, skin
down to next joint and remove flesh from wing-bones;
push skin forward to base of skull, and if skull is not too
large (it is in ducks, woodpeckers, and some other birds),
on over it to ears and eyes; be very careful in loosening
the membrane of ears and in cutting nictitating membrane
of eyes; do not cut into eyeball; remove eyeballs without
breaking; cut off base of skull, and scoop out brain;
remove flesh from skull, and ‘‘ poison ’’ the skin by dust-
ing it thoroughly with the powdered arsenic and alum
mixture. Turn skin right side out, and clean off fresh
blood-stains by soaking them up with corn-meal; wash
off dried blood with water, and dry with corn-meal.
Corn-meal may be used during skinning to soak up blood
and grease.

There remains to stuff the skin. Fill orbits of eyes with
cotton (this can be advantageously done before skin is
reversed); thrust into neck a moderately compact, elastic,
smooth roll of cotton about thickness of the natural neck;
make a loose oval ball of size and general shape of bird’s
body and put into body-cavity with anterior end under
the posterior end of neck-roll; pull two edges of abdominal
incision together over the cotton, fasten, if necessary,
with a single stitch of thread, smooth feathers, fold wings
in natural position, wrap skin, not tightly, in thin sheet
of cotton (opportunity for delicate handling here) and put
away in a drawer or box to dry. Before putting away tie
label to leg, giving date and locality of capture, sex and
measurements of bird, and name of collector. Before
bird is put into permanent collection it should be labelled
with its common and scientific name.

The mounting of birds in lifelike shape and attitude is
hard to do successfully; and a collection of mounted birds
REARING ANIMALS AND MAKING COLLECTIONS 341

demands much more room and more expensive cabinets
than one of skins. For instructions for the mounting of
birds see Davie’s ‘‘ Methods in the Art of Taxidermy,’’
pp. 39-57; or Hornaday’s ‘‘ Taxidermy and Zoological
Collecting.’’ For a more detailed account of making
bird-skins, see also these books, or Ridgway’s ‘‘ Direc-
tions for Collecting Birds.’’

In collecting birds’ nests cut off the branch or branches
on which the nest is placed a few inches above and below
the nest, leaving it in its natural position. Ground-nests
should have the section of the sod on which they are
placed taken up and preserved with them. If the inner
lining of the nest consists of feathers or fur put in a
‘«moth-ball ’’ (naphthaline).

To preserve birds’ eggs they should be emptied through
a single small hole on one side by blowing. Prick a
hole with a needle and enlarge with an egg-drill (obtain
of any dealer in naturalists’ supplies. Blow with a
simple bent blowpipe with point smaller than the hole.
After removing contents clean by blowing in a little
water, and blowing it out again. After cleaning, place
the egg, hole downward, on a layer of corn-meal to dry.
Label each egg by writing on it near the hole a number.
Use a soft pencil for writing. This number should refer
to arecord (book) under similar number, or to an ‘‘ egg-
-blank,’’ containing the following data: name of bird,
number of eggs in set, date and locality, name of col-
lector, and any special information about the eggs or nest
which the collector may think advisable. The eggs may
be kept in drawers or boxes lined with cotton, and di-
vided into little compartments.

For detailed directions for collecting and preserving
birds’ eggs and nests, see Bendire’s ‘‘ Directions for Col-
lecting, Preparing, and Preserving Birds’ Eggs and
342 APPENDIX Il

Nests ’’ or Davie's ‘‘ Methods in the Art of Taxidermy,’’
pp. 74-78.

* Mammals.—Any mammal intended for a scientific
specimen should be measured in the flesh, before skinning,
and as soon after death as practicable, when the muscles
are still flexible. (This is particularly true of larger
species, such as foxes, wildcats, etc.) The measure-
ments are taken in millimetres, a rule or steel tape being
used. (1) Total length: stretch the animal on its back
along the rule or tape and measure from the tip of the
nose (head extended as far as possible) to the tip of the
fleshy part of tail (not to end of hairs). (2) Tail: bend
tail at right angles from body backward and place end of
ruler in the angle, holding the tail taut against the ruler.
Measure only to tip of flesh (make this measurement with
a pair of dividers). (3) Hind foot: place sole of foot flat
on ruler and measure from heel to tip of longest toe-nail
(in certain small mammals it is necessary to use dividers
for accuracy). The measurements should be entered on
the label, along with such necessary data as sex, locality,
date, and collector’s name.

Skin a mammal as soon after death as possible. Lay
mammal on back and with scissors or scalpel open the
skin along belly from about midway between fore and hind
legs to vent, taking care not to cut muscles of abdomen.
Skin down on either side of the body by working the skin
from flesh with fingers till hind legs appear. Use corn-
meal to stanch blood or moisture. With left hand grasp
a leg and work the knee from without into the opening
just made; cut the bone at the knee, skin leg to heel and
clean meat off the bone (leaving it attached of course to
foot). In animals larger than squirrels skin down to tips

* The following directions for making skins of mammals were written

for this book by Mr. W. K. Fisher of Stanford University, an experienced
collector,
REARING ANIMALS AND MAKING COLLECTIONS 343

of toes. Do the same with other leg. Skin around base
of tail till the skin is free all around so that a grip can be
secured on body; then with thumb and forefinger hold the
skin tight at base of tail and slowly pull out the tail. In
small mammals this can be done readily, but in foxes it
is often necessary to split the skin up along the under side
and dissect it off the tail-bones. After the tail is free
skin down the body, using the fingers (except in large
mammals) till the fore legs are reached; treat the fore legs
in the same manner as hind legs, thrusting elbow out of
the skin much asa person would do in taking off a coat;
cut bone at elbow; clean fore-arm bone. Skin over neck
to base of ears. With scalpel cut through ears close to
skull. With scalpel dissect off skin over the head (taking
care not to injure eyelids) down to tip of nose, severing
its cartilage and hence freeing skin from body. Sew
mouth by passing needle through under lip and then across
through two sides of the upper lip; draw taut and ti
thread. Poison skin thoroughly. Turn skin right side
out. Next sever the skull carefully from body, just where
the last neck-vertebra joins the back of the skull. It is
necessary to keep the skull, because characters of bone and
teeth are much used in classification. Remove superfluous
meat from the skull and take out brain with a little spoon
made of a piece of wire with loop at end. Tag the skull
with a number corresponding to that on skin, and hang
up to dry. A finished specimen skull is made by boiling
it a short time and picking the meat off with forceps,
further cleaning it with an old tooth-brush, when it is
placed in the sun to bleach. Care must be taken always
not to injure bones or dislodge teeth.

Mammals are stuffed with cotton or tow; the latter is
used in species from a gray squirrel up. Large mammals
stuffed with cotton do not dry readily, and often spoil.
Being much thicker-skinned than birds, mammals require
344 APPENDIX Il

more care in drying and ordinarily require a much longer
period. Soft hay may be substituted for tow; never use
feathers or hair. Roll a longish wad of cotton about the
size of body and insert with forceps, taking care to form
the head nearly as in life. Split the back end of the cot-
ton and stuff each hind leg with the two branches thus
formed. Roll a piece of cotton around end of forceps
and stuff fore legs. . Place a stout straight piece of wire
in the tail, wrapping it slightly to give the tail the plump
appearance of life. (If the cotton cannot be reeled on to
the wire evenly, leave it off entirely.) Make the wire
long enough to extend half way up belly. Sew up slit in
belly. Lay mammal on belly and pin out on a board
by legs, with the fore legs close beside head, and hind
legs parallel behind, soles downward. Be sure the label
is tied securely on right hind leg.

For directions for preparing and mounting skeletons of
birds, mammals, and other vertebrates, see the books of
Davie and Hornaday already referred to.

Fishes, batrachians, reptiles, and other animals.—The
most convenient and usual way of preserving the other
vertebrates (not birds or mammals) is to put the whole
body into 85 per cent alcohol or 4 per cent formalin.
Batrachians should be kept in alcohol not exceeding 60
per cent strength. Several incisions should always be
made in the body, at least one of which should penetrate
the abdominal cavity. Anatomical preparations are simi-
larly preserved. By keeping the specimens in glass jars
they may be examined without removal. Fishes should
not be kept in formalin more than a few months, as they
absorb water, swell, and grow fragile.

Of the invertebrates all, except the insects, are pre-
served in alcohol or formalin. The shells of molluscs
can be preserved dry, of course, in drawers or boxes
divided into small compartments.
APPENDIX III
CLASSIFICATION OF ANIMALS

As the animals referred to in this book are not taken
up in a rigorous systematic or classificatory order, but are
grouped together to some extent rather according to
similarities of habit or habitat, all the different species of
animals mentioned by either scientific or vernacular name
are introduced into the following table of classification *
of animals to branches and classes.

KINGDOM ANIMALIA.
BRANCH I. PROTOZOA.

Class I, RHIZOP’ ODA.
Ame’ba, sun animalcule, Rosali!na va'rians, For
minif’era,
Class II. MYCETOZO’ A.
Class III. MASTIGOPH’ ORA.
Class IV. sPOROZO' A.
Class V. INFUSO’ RIA.
Parame'ctum, Vorticél’la, bell animalcule, slipper
animalcule, S7#én’tor.

BRANCH II. PORIF’ ERA.
Class I, PORIFERA.
Granta, glass sponge.

*The classification here used is that adopted by Parker and Haswell’s
Text-book of Zoology (1897).
345
346 APPENDIX III

BRANCH III. CQLEN’ TERA’ TA (sé lén’te ra’ta).

Class I. HYDROZO’A.

Ffy"dra, Obé'la, sea-anemone, Bund'des califor-
nica, jelly-fish, medusa, PAtsa'tza, Portuguese
man-of-war, Gonioné’ mus vertens.

Class II. SCYPHOZO’A (si {0 z0’ a),

Jelly-fish, medusa.
Class III. ACTINOZO’ A.

Coral, polyp, Jladrép'ora cervicornis.
Class IV. CTENOPH’ ORA (tén6ph’ ora).

BRANCH IV. PLATYHELMIN’ THES.

Class I. TURBELLA’ RIA.
Plani’ria.

Class II. TREMATO’ DA.

Class III. CESTO’ Da.
Tapeworm.

BRANCH V. NEMATHELMIN’ THES.
Class I. NEMATO’ DA.
Vinegar-eel, Anguilli'la, Trichi'na spirals, hair
worm, Uncind' ria,
Class II. ACANTHOCEPH’ ALA.
Class II]. CHETOG’ NATHA (két6g’ na tha).

BRANCH VI. TROCHELMIN’ THES.

Class I. ROTIF’ ERA. Class II]. GASTROT’ RICHA.
Class II. DINOPHI’ LEA.
BRANCH VII. MOLLUSCOI DA.

Class J. POLYZO’ A. Class II]. BRACHIOP’ oDA.
Class II. PHORO’ NIDA.
Class I.
Class II.
Class III.

Class IV.
Class V.

Class I.
Class II.

Class III,
Class IV.

Class I.

Class II.
Class III.

CLASSIFICATION OF ANIMALS 347

BRANCH VIII. ECHINODER’ MATA.

ASTEROI’ DEA.

Starfish, As/eri’na mineata, Asté'rias ocra'cia.
OPHIUROI!’ DEA.
ECHINOI’ DEA.

Sea-urchin, Strongylocéntro'tus francisca’nus, cake-

urchin, sand-dollar.

HOLOTHURO!’ DEA. Class VI. C¥sTOI’ DEA.
CRINOI’ DEA. Class VII. BLASTOI’ DEA,

BRANCH IX. ANNULA’TA.

CHETOP’ opa (ké top’ oda).
Earthworm.
GEPHYRE’A (jéferé’a).
ARCHI-ANNEL’ IDA.
HIRUDIN’ EA.
Leech, Clepsi'ne.

BRANCH X. ARTHROP’ ODA.

CRUSTA’ CEA.

Crayfish, crab, lobster, pill-bug, water-flea, spider-
crab, barnacle, kelp-crab, rock-crab, hermit-
crab, oyster-crab, Macrocheira, Bala'nus, Pollic’-
apes polymenus, Brachyno'tus nudus, Can'cer pro-
ductus, Epialtus prodictus, Pdg'arus samuelis,
damp-bug, wood-louse, Cy’clops, Isopod, Saccu-
li'na, Copepod, Penél'la, Cochodér'ma virga'tum.

ONYCHOPH’ ORA. (on y kOf’o ra)
MYRIAP’ ODA.

Thousand-legged worm, centiped, milliped, gal-

ley-worm, /ulus, Scolopén'dra, Scutig’ era for'ceps,
348 APPENDIX III

Class IV. INSEC’ TA.

Mosquito, Cz’/ex, silkworm, beetle, forest tent-
caterpillar moth, violet-tip butterfly, CZstocam'pa
disstria, Clisiocém'pa america'na, Polygé'nia in-
lerrogationis, dragon-fly, damsel-fly, gall-fly,
grasshopper, locust, cockroach, bee, tiger-beetle,
squash-bug, sphinx-moth, May-fly, house-fly,
midge, carrion-beetle, Promé'thea, Melan'oplus,
Therioplic'tes, horse-fly, Ammoph'ila, digger-
wasp, solitary wasp, plum curculio, Conotrach’-
elus nenuphar, caddis-worm, case-worm, caddis-
fly, case-fly, water-strider, Mygrdt/rechus, pre-
daceous diving-beetle, back-swimmer, water-scav-
enger-beetle, water-boatman, water-tiger, Djé’-
zcus, swallowtail butterfly, Papil’1o ri’/ulus, mon-
arch butterfly, milkweed butterfly, cecropia moth,
polyphemus moth, grapevine sphinx, Ampe’-
liph'aga my’ron, ants, aphis-lion, peach-tree
borer, Sanninotdea exttiosa, army-worm, Leu-
ca’nia unipuncta, Chryso' pa, rose-aphid, golden-
eyed fly, lace-winged fly, Crca’da, seventeen-
year locust, harvest-fly locust, dog-day locust,
Cica’da septendecim, katydid, cricket, solitary bee,
mining - bee, carpenter-bee, leaf-cutter bee,
quince curculio, Conotrach’elus crategt, cater-
pillar, regal walnut moth, Cvtherd'nia rég'alis,
hawk-moth, mantis, bag-worm, Ca/’7g0, owl-but-
terfly, Zol’ype vél'leda, Cast'nia, AMlicrop'tervx
aruncil la, Lycena, Grap' ta, walking-stick, Draph-
erom'era fimord'ta, Phyl’ hum, Kae'lima, viceroy-
butterfly, And’sia plex’ ippus, Basilar' chia archif’-
pus, ichneumon, pigeon-horntail, Z7rém’ex, Tha-
Llés'sa, Stvlops, Vird-louse, Nir'mus prestans,
Ves'pa, Vés' pidx, yellow-jacket, hornet, bumble-
bee, parnassian butterfly, Paras’ sius smin'theus,
Hessian fly, buffalo-bug, carpet-beetle.
CLASSIFICATION OF ANIMALS 349

Class V. ARACH’ NIDA.
Labyrinth-spider, running spider, Lycds’ide,
trap-door spider, turret-spider, tarantula, jump-
ing spider, At’tide, Thomis’ide, crab-spider,
Myga'le, Argi'ope, Epei’ride, Tetragnath'a sp.,
triangle-spider, Hypi0’/es sp.

BRANCH XI. MOLLUS’CA.

Class I. PELECYP’ ODA.
Oyster, Os! trea virginiana, Phd'las, Chlords'tomum
Sunebrale, clam.
Class II. AMPHINEU’RA.
Class III. GASTROP’ODA.
Snail, slug, <Artoli*max calfornica, nudibranch,
Doris tubercula'ta, Echinodoris, Trio'pha mo-
desta, Pur'pura saxicola, Littori’na scutulata, Ac-
mara spectrum, Mytilus californianus.
Class IV. CEPHALOP’ ODA.
Squid, Ommdas' trephes californica.

BRANCH XII. CHORDA’TA.

SuB-BRANCH I. ADELOCHOR’DA. Class ADELOCHORDA.
SuB-BRANCH II. UROCHOR’DA. Class UROCHORDA.
SuB-BRANCH III. VERTEBRA’TA.
Division A. ACRA’NIA. Class ACRANIA,
Division B. CRANIA’TA.

Class I. C¥CLOSTOM’ ATA.
Class II. Pis’cEs (pis séz).

Catfish, sunfish, Axfennd’rius, pipefish, sea-horse,
salmon, stickleback, bass, dogfish, trout, her-
ring, goby, darter, perch, bullhead, horned
pout, sucker, minnow, chub, charr, whitefish,
350 APPENDIX III

ayu, eel, codfish, flounder, skate, stingray, tor-
pedo, shark, sawfish, remora, clingfish, flying-
fish, L'vonaules nigricans,

Class III]. AMPHIB’IA.

Toad, frog, salamander, tadpole, eft, tree-toad,
triton.

Class IV. REPTIL’IA.

Lizard, snake, turtle, tortoise, Chelo’ne mij’das, Tes-
tu'do, glass-snake, joint-snake, horned toad, skink,
Gila monster, Eumé'ces skeltonianus, Helodér'ma
horridum, Pituophis bello'na, chameleon, python,
Thamnophis parietalis, Lampropcltis boylit, blue
racer, garter-snake, water-snake, greensnake,
blacksnake, chain-snake, king-snake, spreading-
viper, blowing-adder, coral-snake, bead-snake,
copperhead, water-moccasin, rattlesnake, croco-
dile, alligator, gavial.

Class V. A’VES.

Chick, robin, oriole, puffin, auk, bush-tit, tailor-
bird, murre, sparrow, crane, duck, curlew, hawk,
crossbill, hornbill, redbird, cardinal grosbeak,
black phcebe, Cardinal’ts cardindl'is, Sayornis
nigricans, Spizcl'la socials arizone, thrush, Zir’-
dus ustuld' tus, Merula migratoria propinqua, Har-
porhin'chus redivivus, humming-bird, upland
plover, crow, blackbird, owl, flycatcher, E’mpid’-
onax fulvifrons prgm@us, ostrich, grouse, tur-
key, sandpiper, snipe, swift, yellow-hammer,
Colap'les auratus, Alég'ascops asto, night-hawk,
swallow, whippoorwill, duck, woodpecker, cross-
bill, gull, turkey-buzzard, horned lark, Osic’oris
alpés'tris, bluebird, eagle, pelican, meadow-lark,
ptarmigan, S/ér’na maxima,

Class VI. MAMMA’ LIA.

Cat, duck-bill, wood-rat, mole, pocket-gopher,

prairie-dog, horse, dog, mouse, beaver, pig,
CLASSIFICATION OF ANIMALS 351

sheep, rat, rabbit, man, cow, whale, dolphin,
porpoise, shrew, camel, reindeer, lion, tiger,
otter, wolf, moose, elk, deer, porcupine, arma-
dillo, bear, fox, hare, fur-seal, Callorhi’nus
ursi’nus, walrus, and all the animals referred to
in Chapter XVI.
INDEX

Illustrations are indicated by an asterisk

Acmara spectrum, *142.

Air-bladder of fishes, 84.

Alce americana, *259, *266.

Alimentary canal of cow, *92; of
earthworm, *91; of flatworm,
*g2; of rabbit, described, go.

Alligator, 228.

Ammophila, bringing cover for
nest, *186; nesting grounds of,
*185; putting inch-worm into
nest, *185.

Ameba, 114; motion of, *115;
movements of, *67.

Ampelophaga myron, *173.

Amphibians, respiration of, 83.

Anatomy, defined, 47.

Anguillula, *147.

Anopheles, 9.

Anosia plexippus, *290.

Antelope, *265, 266.

Antenna of carrion beetle, show-
ing smelling-pits, *106.

Antennarius and nest, *43.

Antilocapra americana, *265, 266.

Ant, little black, *313.

Ants and rose aphids, *178.

Ants, how to make artificial nest
for, 310; feeding on honey-
dew, 313; life and habits of,
309; robber, 314; slave-making,
314; visiting aphids, 175.

Ape, 269, 272.

Aphids, 174.

Aphids, rose, and ants, *178

Aphis lion, 179.

Apis mellifica, *307.

Apple-tent caterpillar moth, larvee
of, *18.

Aquaria, 329;
332.

how to maintain,

 

Aquarium, battery jar,
water-plants for, 332;
pond snails, *52.

Arctics, color of animals of, 287.

Arctomys monax, 260.

Argiope, *199.

Arvolimax californica, *141

Army-worm, *177.

Arthropoda, 154.

Artiodactyla, 264.

Asterias ocracia, *135.

Asterina mineata, *135.

Auditory organ of locust, *109.

Auditory organs, 107.

Ayu, 212.

*332;
with

Baboon, 272.

Backboned animals, homes of, 42.

Back-swimmer, *168, 169.

Badger, 269.

Bag-worm, *278.

Balena glacialis, 263.

Balena mysticetus, 263.

Balenide, 263.

Balenoptera sulfurea, 263.

Balanus, *155.

Ballooning of spiders, 206.

Barbados earth formed by shells
of ocean Protozoa, 122.

Barnacle, acorn, *155; stalked,
*155.

Barnacles, *155; on copepod par-
asites of flying-fish, *294.

Barriers to distribution of animals,
320.

Basilarchia archippus, *290.

Bass, 211.

Bat, 261; brown, 262; hoary,
*262; red, 262; wing of, 261.
Batrachians, 215; care of young

353
354
of, 44; circulation of blood in,
95; heart of, 95, *96; how to
preserve, 343.

Bear, black, 269; brown, 269;
cinnamon, 269; grizzly, 269;
polar, 269.

Beaver, 260; nest of, 46.

Bee, leaf-cutter, 184.

Beehive, observation, *303.

Bees, solitary, 182.

Beetle, carrion, antenna of, show-
ing smelling-pits, *106.

Beetle, tracheal system of, *15,
*82,

Biceps muscle of man, *71.

Big horn, 257, 266.

Bills of bird, 61, 247.

Bill-bug, 157.

Bird, bit of feather of, magnified,
*60; external parts and regions
named, *62; feathers of, 60;
leg of, 63; life-history of, 34;
louse of, *299; nesting of, 34;
wing of, 62.

Birds, 230; bills of, 247; care of
young of, 44; classification of,
233; collecting, 337; colors of,
285; economics of, 250; eggs,
how to preserve, 340; feeding
habits of, 250; feet of, 245;
flight of, 248; how to skin, 337;
identification of,233; maritime,
eggs of, 44; moulting of, 244;
nests, how to collect and pre-
serve, 340; protection of, 250.

Bison, 266, *267.

Bison bison, 266, *267, *268.

Bite of rattlesnake, remedies for,
228.

Black-snake, 226.

Blood, circulation of, in fin of
fish, 57; how it circulates, 93.

Blowing viper, 226.

Blue-racer, 226.

Bombyx mort, 9.

Bones of forelimb of vertebrates,
*74; of leg of cat, how arranged,
72.

Books, reference, list of, 327

Brachynoius nudus, *155.

Brain of cat,*101; of mouse, *103;
of snake, *103; of sparrow, *103;
of sunfish, #103; of toad, *103.

Brains of vertebrates, *103.

Breathing of animals, 79.

 

INDEX

Breeding-cage made of flower-pot
and lamp chimney,*331, made
of soap-boy, *330.

Buffalo, 266, *267, *268.

Bullfrog, 217.

Bull-head, 211.

Bumble-bee, *315.

Bumble-bees, life of, 315.

Bunodes californica, *127.

Butterflies, 171; Grapta, protec-
tive color of, 288; how to
spread and preserve, 336; scales
of, *283; setting board for,
#338; spreading board for, *337,
#338; swallow-tailed, *170.

Butterfly, bit of wing of, *283;
dead -leaf, *289; milkweed,
*290; monarch, *2Gg0; monarch,
larve of, *290; monarch, mim-
icked by vicervy, 291; owl,
*282; parnassian, *320, vice-
roy, *290; viceroy, mimicking
monarch, 291.

Cachalot, 263.

Caddis-worm, 165; cases of, *165;
nets of, 166.

Cake-urchin, 138.

Calf, taste papilla of, *1o5.

Caligo, *282.

Callorhinus urstnus, *300.

Cambarus, *151.

Cancer productus, *155.

Canis jamiliaris, 269;
269; nubilus, 269.

Carbon dioxide, how formed, 79.

Cardinalis cardinalis, *231.

Caribou, 266.

Carnivora, 266.

Carpenter-bee, 183; nest of, *1&3.

Case-worm, 165.

Castnia, scale from wing of, *283.

Castor canadensis, 260.

Cat, brain of, *1ror; circulation
in leg of, *98; heart of,*97 ; mus-
cles of leg of, *72; skeleton of,

skeleton of, described,

latrans,

ay;
73-
Caterpillar parasitized, *208.
Catfish, 211, 212; eggs of, 42.
Cavia, 260.
Centiped, *160; skein, 160, *161.
Cervus canadensis, *264, 266.
Cete, 262.
Chain-snake, 226.
INDEX

Chalk formed by cells of ocean
Protozoa, 121.

Chameleon, 223.

Charr, 212.

Chelone mydas, *220

Chimpanzee, 272.

Chipmunk, *254, 260.

Chironomus, nervous system of,
#102,

Cheiroptera, 261.

Chitin, defined, 13.

Chlorostomum funebrale, *142.

Chrysopa, adult, eggs, larve, and
pupal cocoon of, *178.

Chub, 211. .

Cicada, pericdical, 179; septende-
cim, *180; showing sound-
making organ, *180.

Circulation of blood, 93; in fin of
fish, 57; in batrachians, 95; in
leg of cat, *98; in fishes, 94; in
mammal, *97; in vertebrates,
94; of reptiles, 95.

Circulatory system of fish, *95.

Circulatory system of young
dragon-fly, *94.

Citheronia regalis, imago of, *172;
larva of, ¥171.

Clam, hard shell, 141; soft shell,
141; edible, 141.

Classification of birds, 233

Clepsine, *145.

Cling-fish, *216.

Clistocampa americana, larve of,
*18; dtsstria, larve of, *175;
disstria, stages of, *17.

Cobweb, 197.

Cochoderma virgatum, *294.

Cockroach, leg of, showing
muscles, *70; trachez in head
of, *83.

Cocoon of silkworm, 15.

Coelenterata, 123, 134.

Colaptes auratus, *247.

Color, uses of, 285; animal, 281;
of birds, 285; of butterflies’
wings, 281; of fishes, 285; of
mammals, 285; uses of, 281;
warming, 288.

Collecting birds, 337; insects, 334.

Collections, how to make, 329.

Comb, honey-bees building, *305.

Commensalism, 157.

Community, honey-bee, life of,
WNT.

 

355

Compound eye of dragon-fly, 22.

Compound eyes, 112.

Condvlura cristata, 261.

Conjugation, 118.

Conotrachelus crataegi, *187; cra-
taegi, immature stages of, *188;
nenuphar, *189.

Copperhead, 222.

Corisa, *169.

Corn, plant-lice of, 314.

Cornea of eye of insect, *111.
Coral island, *129; reef, *130;
skeleton of branching, *131.

Coral-snake, 226.

Corals, 126.

Cow, alimentary canal of, *92.

Coyote, 269.

Crab, 154, *155.

Crab-spider, *195, 196.

Crayesh, 149; ventral aspect of,

151.

Cricket, showing sound-making
organ, *182.

Crocodile, 228.

Crow, food of, 251.

Crustacea, 154.

Culex sp., stages of, *3.

Cyclops, 157, *158.

Dace, horned, 211.

Damp-bug, *157.

Damsel-fly, *26.

Darters, 211.

Deer, black-tailed, 266; mule, 266;
red, 266; virginiana, 266 ; white-
tailed, 266:

Delphinade, 262.

Dendrostomum cronjhelmt, *149.

Desert, color of animals of, 287.

Development of animals, 1.

Diapheromera femorata, *287.

Diaphragm, use of, in respiration,

85.
Didelphys virginiana, 256.
Diemyctylus torosus, *218.
Digestion, 86.
Digestive cavity of polyp, *9o.
Digger-wasps, 182, 184.
Distribution of animals, 319; bar-
riers to, 320; map showing,
322.
Diving-beetle, predaceous, *168.
Division, multiplication by, 118.
Dog, 269; central nervous system
of. *100; muscles of, *75.
356

Dogfish, muscles of, *75.

Dolphin, 262.

Doris tuberculata, *141.

Dragon-flies, how to spread and
preserve, 336; life-history of,

21.

Dragon-fly, *22; egg-laying of, 23;
nymphs of, 23, *24; transfor-
mation to winged stage, 25;
young, circulatory system of,
¥*94; young, mouth parts of,
*89,

Drawings, students’, 325.
Drone of honey-bee, *307.
Dyticus, *168; larva of, *169.

Ear of man, *107.
Ears, 107
Earthworm, 144;alimentary canal
of, *g1.
Echinodermata, 134, *135.
Echinodorts sp., *141.
Eciton, 314.
Economics of birds, 250.
Edentata, 256.
Eel, 212.
Eft, little green, 219;
brown, *218.
. Egg-cocoon of labyrinth spider,
#38, *208.
Egg-laying of dragon-fly, 23; of
silkworm moth, 17.
Eggs of katydid, *181; birds,
how to preserve, 340; of cat-
fish, 42; of mosquitoes, 2, *3; of
pipe-fish, 43; of salmon, 43; of
sea-horse, 43; of silkworms, 9;
of snake, 44; of Surinam toad,
44; of toad, 27.

Egg-sac of running spider, *39,
195.

Electric ray, 214.

Elephantiasis, disseminated by
mosquitoes, 9.

Elk, *264, 266.

Energy of animal, how derived,
78.

English sparrow, *59.

Epzaltus productus, *155.

Erethizon dorsatus, 260;
thus, 260.

Eumeces skeltonianus, *223.

Exonautes unicolor, *294.

Eye, compound, of dragon-fly, 22;
compound, section of, of moth,

western

epixan-

 

INDEX

*r12; of horse-fly, 111; of
insect, cornea of, *111; of
jellyfish, *111.

Eye, section of compound, of
moth, *112; of vertebrate, *111

Eyes, 109; compound, *112.

Eyes of spider, 193.

Fangs, of rattlesnake,
#228.

Feather, bit of, magnified, *6o0.

Feathers of bird, 60.

Feeding habits of birds, 250.

Feet of birds, 245.

Felide, 269.

Felis concolor, 269.

Fer, 266.

Fiber zibethicus, 260.

Fin of sunfish, 55. i

Fish, circulatory system of, 95;
flying, parasitized, #294;
heart of, 94; muscles of, 74;
porcupine, 213.

Fishes, 210; air-bladder of, 84;
care of young of, 42; circulation
of blood in, 94; colors of, 285;
how to preserve, 343.

Flat-worm, alimentary canal of,

poison,

‘92.

Flight of birds, 248.

Flounder, 212; winter, *213.

Fly, golden-eyed, *178; lace-
winged, *178, 179.

Food, how animals obtain and
digest, 86; nature of, 88; neces-
sity of, 77; of crow, 251; spe-
cial means to get, 275.

Forest tent - caterpillar
stages of, *17.

Formicary, how to make, 310.

Fox, red, 269.

Frog, 31.

Frog-fish and nest, *43.

Frogs, 217.

Fur-seal, 268, 269.

moth,

Gall of oak, *37.

Galley-worm, 159, *160,

Garter-snake, *225,.

Gavial, 229.

Gephyrean, *149.

Gills for respiration, 81; of sun-
fish, 56; tracheal, of nymph of
Mayfly, *163; with head of
trout, *82.
INDEX

Glires, 258.

Goat, Rocky Monntain, 266.

Gontonema vertens, *132.

Gopher, nest of, 46.

Gopher-snake, *224.

Gophers, pocket, 260.

Gorilla, 272.

Gnawers, 258.

Grantia, *125.

Grapta, bit. of wing of, *284; pro-
tective color of, 288.

Grasshopper, external structure
of, 48.

Green-fly, 174.

Grosbeak, cardinal, 231.

Ground-hog, 260.

Ground-squirrel, 260.

Guinea-pig, 260.

Habits, feeding, of birds, 250; of
birds, 244.
Hairworm, 146.
Harporhynchus redivivus, *236.
Hatching of, toad, 27.
Head of cockroach, trachee in,
83.

Hearing, sense of, 107.

Heart of batrachians, 95, *96; of
cat, *97; of fish, 94; of rep-
tiles, 95, *96; of vertebrates,
94; of young dragon-fly, *94.

Hedgehog, 261.

Heloderma horridum, *223. .

Hermit-crab, *155, 156.

Herring, 212.

Hippocampus kelloggi, *214.

Hive, honey-bee, life in, 305.

Homes of backbonéd animals, 42;
of insects and spiders, 36.

Homo sapiens, 269.

Honey-bee, brood cells of, *308;
head and mouth parts of, *88;
gathering pollen and nectar,
#304; life of, 302; queen,
drone, worker, *307.

Honey-bees building comb, *305.

Honey-dew, eaten by ants, 313;
secreted by plant-lice and scale
insects, 313.

Hornets, life of community of, 316.

Horn-tail pigeon, *298; para-
sitized by Thalessa, 299.

Horse-fly, eye of, 111.

House-fly, nervous system of,

¥102.

 

357

\

Humming - bird, nest of, *35;
ruby-throat, nest and eggs of,
#237, :

Hunting-spiders, 193.

Hydra, *122.

Hyena, 269.

Hygrotrechus, *167.

Hyptiotes, *205.

Ichneumons, parasitic habits of,
297.

Ichneumon parasites of caterpillar,
#298. :

Imago, defined, 7.

Inch - worm, used asfood by soli-
tary wasps, 188.

Insect, cornea of eye of, *111;
dead-leaf, protective markings
of, 288, *289; killing-bottle for,
how to make, 334; pins, 335;
properly pinned up, *336; sec-
tion through thorax of, showing
muscles, *70; twig, *287; walk-
ing-stick, *287.

Insectivora, 261.

Insects, 162; brook, 163; com-
pound eyes of, 112; homes of,
36; how to collect and pre-
serve, 334; how to rear, 330;
killing-bottle for, *334; mouth
parts of, 87; parasitic, 297;
pond, 163; respiration of, 82.

Invertebrates, skeleton of 69.

Jack-rabbit, 260.

Jaguar, 269.

Jaws of spider, 193.

Jellyfish, *132; eye of, *111.
Jellyfishes, 131; colonial, 133.
Julus, *160.

Kallima, *289; protective mark-
ings of, 288.

Kangaroo, 256.

Katydid, *181; color of, 287.

Kelp-crab, *155.

Killing-bottle for insects, *334.

King-snake, *226.

Labyrinth spider, egg cocoon of
#38

Lampropeltis byolu, *226.
Land-crab, 156.
Larks, horned, 251.
358

Larva, defined, 4; of violet -tip
butterfly, Polygonia interroga-
tionis, pupating, *19; of silk-
worm moth, 11.

Larval stage, defined, 4.

Lasiurus borealis, 262;
*262.

Leech, *145; medicinal, 146.

Leg of cat, how muscles and bones
are arranged, 72; of bird, 63;
of cockroach, showing muscles,
*70,

Lemur, 271.

Leopard, 269.

Lepus campestris, 258;
258.

Leucania unipuncta, *177.

Life-history of bird, 34; of dragon-
flies, 21; of mosquito, 2; of
moths and butterflies, 20; of
silkworm, 9; of silkworm moth,
9; of toad, 27.

Lion, 269.

Littorina scutulata, *142.

Live-cage made of flower-pot and
lamp chimney, *331; made of
soap-box, *330.

Live-cages, 329.

Lizard, *222.

Lobster, 154.

Locomotion of animals, 64; of
protozoa, 66.

Locust, auditory organ of, *109;
external structure of, *50;
seventeen-year, 179, *180.

Locusts, *48.

Louse, bird, *299.

Lungs, 84; of mouse, *85.

Lynx, 269.

Lynx rufus, 269.

Lycena, bit of wing of, *283.

cinersus,

nuttalli,

Macrochetra, 155.

Madrepora cervicornis, *131.

Malaria, disseminated by mos-
quitoes, 9.

Mammal, alimentary canal of,
described, 90; circulation of
blood in, *97.

Mammals, 253; care of young of,
44; classification of, 256; colors
of, 285; how to skin, 341; uses
of, 253.

Man, ear of, *107;
puscle of, *105.

tactile cor-

 

INDEX

Man - of - war,
*134.

Mantis, preying, *277.

Map showing distribution of ani-
mals, 322.

Markings of animals, 281; uses of,
281.

Marsupialia, 256.

Mayfly, 163, *164.

Mayfly, nymph of, 163.

Medusa, *132.

Megascops asio, *248.

Melanoplus, auditory organ of,
¥ 109.

Merula
¥235.

Micropteryx aruncella, scale from
wing of, *283.

Mice, 260.

Midge, nervous system of, *102.

Milliped, *160.

Mimicry, 291.

Mink, 269.

Minnows, 211.

Mole, nest of, 46.

Moles, 261; star-nosed, 261.

Mollusca, 139.

Monster, gila, *223.

Monkey, howling, 272; capuchin,
272; spider, 272; squirrel,
272.

Monkeys, 269, 272; catarrhine,
272; platyrrhine, 272.

Monomorium minutum, *313.

Monotremata, 256.

Moose, *259, 266.

Mosquito, beak of, *8; distribu-
tion of, 8; imago stage of, 7;
larva of, *3, 4; life-history of,
2; mouth parts of, *8, *88;
pupa of, *3, 6; stages of, *3.

Mosquitoes, 2; as disseminators
of disease, 9; eggs of, 2, *3;
hatching of, 2; remedies for,

Portuguese, 133,

migratoria propinqua,

9.

Moth, death's head sphinx, *286.
grape-vine sphinx, *173;
mouth parts of, *90, *276; par-
asitized, larvee of, *297; peach-
tree borer, *176; regal walnut,
imago of, 172; regal walnut,
larve of, *171; section of com-
pound eye of, *r12.

Moths, 171; and butterflies, life-
history of, 20; cecropia, *174;
 

INDEX

of silkworms, 16, 17; mimick-
ing wasps, *292; scales of, *283.
Motions of animals, 64.

Moulting of birds, 244; of silk-
worms, 13.
Mouse, 254; brain of, *103;

lungs of, *85.

Mouth parts of honey-bee, *88;
of insects, 87; of mosquito, *8,
*88; of moth, *276; of sphinx
moth, *90; of young dragon-
fly, *89.

Movements of Ameba, *67.

Mud-turtle, 221.

Multiplication of animals, 273.

Murres and eggs, *45.

Mus decumanus, 260.

Muscle, an engine, 77; biceps, of

man, *71; of animals, 68; of
dog, *75; of dogfish, *75; of
fish, 74; of leg of cat, how

arranged, 72; of leg of cat, *72;
of shark, *75.

Muskrat, 260.

Mus rattus, 260.

Mustelidez, 269.

Myotis subulatus, 262.

Myriapoda, 161.

Mytilus calijornianus, *142.

Nature, selection by, 275.

Nectar, honey-bees gathering,
¥* 304.

Neotoma pennsylvanica, 260.

Nereid, *149.

Nereis sp., *149.

Nervous system, central, 100;
central, of dog, *100; of house-
fly, *102; of midge, *102; of
vertebrates, 100.

Nest, artificial, for ants, how to
make, 310; of frogfish, *43;
humming-bird, *35; of oriole,
*36; of stickleback, 44; of
trap-door spider, *40, *41, *196,
*197; of turret spider, 41, *42,
*198; of yellow-jacket, *316;
of yellow-jacket queen, *317.

Nesting habits of trap-door spider,
39; of bird studied, 34; of
murres, *45.

Nests, birds’, how to collect and

lie preserve, 340.
~ Net, insect, how to make, 334.
Nirmus prestans, *299.

*

 

359

Note-books, students’, 325.
Nudibranchs, 141.
Nymphs of dragon-fly, 23, *24.

Oak-gall, *37.

Obelia, digestive cavity of, *9o.
Odocotleus americanus, 266.
Ommatostrephes californica, *143
One-celled animals, 116,
Opossum, 256.

Orang-outang, 272.

| Orb-web, 200, *201; diagram of,

*201; how constructed by
spider, *203; spider putting
in foundation lines for, *202.
Oreamnos montanus, 266.
Oriole, nest of, *36.
Ostrea virginiana, *139.
Ostriches, *245; young, *246.
Otocoris alpestris, *251.
Otter, 269.
Oxygen, how obtained, 79.
Oxygen, necessity of, 77.
Oyster, *139; young, *139.
Oyster-crah, 156.
Ovts canadensis, *257, 266.

Pagurus samuelis, *155.

Panther, 269.

Papilio rutulus, *170.

Paramoecium, *68, 116, *117.

Parasites, 293; copepod, on fly-
ing-fish, *294; degeneration
of, 293; ichneumon, of moth
larve, *297; internal, 295.

Parts, external, of bird named,
¥*62.

Parnassius smintheus, *320,

Penella, *294. .

Perches, 211.

Perissodactyla, 264.

Phoca vitulina, 268.

Pheebe, black, nest and eggs of.
#232,

Pholas, *140.

Physalia sp., *134.

Physeter macrocephalus, 263.

Physeteride, 262.

Physiology, defined, 47.

Pickerel-frog, 217.

Pinnotheres, 156.

Pins, insect, 335.

Pipe-fish, eggs of, 43.

Pituophis bellona, *224.

Planaria, alimentary canal of, *92
360

Plant-lice, 174; honey-new se-
creted by, 313; of corn, 314.
Plants for use in aquarium, 332.

Plectrophenax nivalis, *251.

Plum curculio, *189.

Poison fangs of rattlesnake, *228.

Pollen, honey-bees gathering, *304.

Pollictpes polymenus, *155.

Polygonta interrogationts, larva of,
pupating, *19; pupa or chrysa-
lid of, *20.

Polynoe brevisetosa, *149.

Polyp, digestive cavity of, *go.

Pond-skater, 167.

Pond snail, external structure of,
52; in aquarium, *52.

Porcupine, 260.

Porpoise, 262.

Pout, horned, 211.

Preservation of animals, 343.

Preserving insects, 334.

Primates, 269.

Protection by special resemblance,
287; of birds, 250; special
means for, 277.

Protozoa, locomotion of, 66;
ocean, 119; respiration of, 80.
Pseudopleuronectes americanus,

¥213.

Puma, 269.

Pupa, defined, 6; of silkworm, 15;
of violet-tip butterfly, Polygo-
ma interrogatioms, *20.

-Pupal stage, defined, 6.

Purpura saxicola, *142.

Quail, protective color of, 287.

Queen, honey-bee, *307.

Quince curculio, *187; immature
stages of, *188.

Rabbit, alimentary canal of, de-
scribed, 90; protective color
of, 287.

Rabbits, 260; in Australia, 274.

Rainbow trout, *212.

Raja erinacea, *215.

Rangijer caribou, 266.

Rat, black, 260; brown, 260.

Rattlesnake, 227; dissection of
head, showing poison fangs,
*228; rattles of, *227; reme-

dies for bite of, 228.
Rattles of rattlesnake, *227.
Rearing animals, 329.

 

INDEX

Redbird, *231.

Reference books, list of, 327.

Reindeer, 266.

Remedies for bite of rattlesnake,
228.

Remora, *216.

Remoropsis brachyptera, *216.

Reptiles, circulation of, 95; how
to preserve, 343.

Resemblance, special protective,
287.

Respiration, 79; by gills, 81; of
amphibians, 83; of insects, 82;
of Protozoa, 80; use of dia-
phragm in, 85.

Robber ants, 314.

Robin, western, *235.

Rock-crab, *155.

Rodents, 258.

Root-cage, for rearing insects, 332.

Rosalina varians, *121.

Reptiles, 219.

Ruminant, 265.

Running spider, with egg-sac, *39.

Sable, 269.

Sacculina, *295; parasitism of,
293.

Salamander, red-backed, 219;
tiger, *218; western brown,
*218,

Salmo irideus, *212.

Salmon, 211; eggs of, 43.

Sand-dollar, 138.

Sanninoidea exttiosa, *176,

Sawfish, 214.

Sayornis nigricans, *232.

Scales of butterflies’ wings, 281;
diagram to show arrangement
of on wing of butterfly, *284,
insertion pits of, *284; of moths
and butterflies, *283.

Scalops aquaticus, 261.

Scavenger-beetle, water, 169.

Sciuropterus volans, 261.

Scturus carolinensis, 261; hud-
sonicus, 261; ludovicanus, 261.

Scolopendra, *160.

Screech-owl, *248.

Scutigera forceps, *161.

Sea-anemones, 126, *127, *128,

Sea-blubs, 132.

Sea-horse, 213, *214; eggs of, 43.

Sea-lion, 268.

Sea- turtle, 220.
INDEX

Sea-urchins, 134, *135, *137, *138.
Seals, 268; fur, parasitized, *300.
Seal harbor, 268.

Selection by nature, 275.

Senses, the special, 103.

Setting board for butterflies, *338;
for butterflies, how to make,
336. :

Shark, muscles of, *75.

Sheep, Rocky Mountain, *257,
266.

Shell-fish, 139.

Shells of Protozoa, 120; sea, 143.

Shrews, 261.

Sight, sense of, 109.

Silkworm, *12; cocoon of, 15;
dissection of, *14; eggs of, 9,
11; feeding of, *12; hatching
of, 11; moths of, 16, 17; pupa
of, 15.

Silkworms, how to rear, 9; _life-
history of, 9; moulting of, 13.
Silkworm moth, egg-laying of, 17;

larve of, 11; life-history of, 9.

Sirenia, 256.

Skate, 214; barn - door,
common, *215,.

Skeleton, 68; of cat, *71; of cat
described, 73; of invertebrates,
69; of vertebrates, 71.

Skinning mammals, 341

Skink, blue-tailed, *223.

Skunk, 269;

Slave-making by ants, 314.

Slipper animalcule, 116.

Slug, giant yellow, *141

Slugs, sea, *141.

Smell, sense of, 105.

Snake, brain of, *103; eggs of,
44.

_ Snakes, 224.

Snowflake, *251.

Social life among animals, 302.

Sound-making of cricket, 182;
organ of Cicada, *180; organ
of cricket, *182.

Spade-foot, 217.

Sparrow, brain of, *103; English,
#59, 230, 273; English, external
structure of, 58; Western chip-
ping, *233.

Spat, oyster, 140.

Special senses, 103.

Sperm-whale, 262.

Spreading adder, 226..

214;

 

361

Spreading board for butterflies,
*337, *338.

Spider and web, *200; ballooning,
ready to sail, *206; catching a,
*191; dropping from pencil,
*191; eyes and jaws of, *192;
how orb-web is constructed,
*203 ; jumping, *195; labyrinth,
egg-cocoon of, *38, *208; long-
legged, *204; make-up of body
of, 192; orb- weaving, *199;
putting in foundation lines for
orb-web, *202; running, with
egg-sac, *39, *194; cobweb-
weaving, 197; funnel web-
weaving, *198; jumping, 195;
spinnerets of, *193; spinning
organs of, 193; trap-door, bur-
row of, *41, *197; trap-door,
with burrows, *40, *196; tri-
angle, and web, *205; turret,
nest of, *42; web-weaving, *194.

Spiders, collecting, 190; homes of,
36; life-history of, 207; running,
194; web-weaving, 196; young,
assembly of, *207; young, webs
of, *207.

Spider crab, 155.

Spiracles, defined, 13.

Spiracles of insects, 82.

Spizella socialts arizone, *233.

Sponge, simple, *125; glass, *126.

Sponges, 125.

Spreading board for butterflies,
how to make, 336.

Squid, giant, *143.

Squirrel black, 261; flying, 261;
fox, 261; gray, 261; red, 261.

Starfishes, 134, *135, *136.

Stentor, *120.

Stickleback, nest of, 44.

Sting-ray, 214.

Strongylocentrotus _franciscanus,
*135, *137, *138.
Structure, external, of English

spatrow, 58; external, of
grasshopper, 48; external, of
locust, *50; external, of pond
snail, 52; external, of sunfish,

54.

Struggle for life, 274.

Students, drawings by, 325; note-
books of, 325.

Stylops, parasitic hebits of, 298,"

Suckers, 211.
302

Sun animalcule, *119.

Sunfish, *55, 210; brain of, *103;
external structure of, 54.

Surface film, used by insects, 5.

Swordfish, 213.

Symbiosis, 157.

Tactile corpuscle of man, *105;
sense, 104.

Tadpoles, 28, *29; life of, 28.

Tailor-bird, nest of, 44.

Tolype velleda, scales of, *283.

Tapeworm, *148, 295, *296; par-
asitic habits, 295.

Taste papille of calf, *105; sense
of, 104.

Tent caterpillars, forest, *175.

Terrapin, red-bellied, 221; yellow-
bellied, 221.

Testudo, *221.

Tetragnatha, *204.

Thalarctos maritimus, 269.

Thalessa, *298; parasitic habits
of, 298.

Thamnophis parvetalis, *225.

Therioplectes, eye of, *111.

Thorax of insect, section through,
showing muscles, *70; thorax
of mammals, 85.

Thrasher, sickle-billed, *236.

Thrush, russet-backed, *234.

Tiger, 269.

Toad, *28, *31, 216; brain of,
#103; eggs and hatching of, 27;
horned, 222; life-history of, 27;
Surinam, eggs of, 44.

Torpedo, 214.

Tortoise, giant Galapagos, *221.

Touch, sense of, 104.

Trachee, *83; defined, 15; of
beetle, *82; of insects, 82; in
head of cockroach, *83.

Tracheal system of beetle, *15.

Transformation of dragon-fly, 25.

Trap-door spider, burrow of, *41;
nesting habits of, 39; with
nests, *4o.

Tree-frog, 217; Pickering’s, *218.

Tree-toad, 217.

Tremex, *298;
Thalessa, 299.

Trichina, 295; parasitic habits,
295; spiralis, 147, *147, *296.

Trichinosis, 147.

Triopha modesta, *141.

parasitized by

 

INDEX

Tripoli, formed by shells of ocean
Protozoa, 122.

Triton, little green, 219.

Trochilus colubris, nest and eggs
of, *237.

Trout, 211, *212; head of, show-
ing gills, *82.

Turdus ustulatus, *234.

auanet spider, nest of, 41, *42,

198.
Turtles, 221.

Uncinaria killing fur-seals, *300.

Ungulata, 263.

Ursus americanus,
bilis, 269.

Uses of color, 285.

269; ~—horra-

Vermes, 149.

Vertebrates, bones of forelimb,
*74; brains of, *103; circula-
tion of blood in, 94; eye of,
*r11; heart of, 94; nervous
system of, 100; skeleton of,

mils

Vespa, nest of, *316; nest of
queen, *317.

Vespide, 316.

Vinegar eel, 146, *147.

Violet-tip butterfly, larva of,
pupating, *19;. pupa or chrys-
alid of, *20.

Vorticella, *68, *117.

Vulpes pennsylvanicus, 269.

Walrus, 269.

Wapiti, *264, 266.

Warning colors, 288.

Wasps, life of, 315; mimicked by
moths, *292.

Water-moccasin, 228.

Water-beetles, 167.

Water-boatmen, *169.

Water-bugs, 160.

Water-flea, 157, *158.

Water-snake, 225.

Water-strider, *167.

Water-tiger, *169.

Wax of honey-bee, how made, 305.

Weasel, 269.

Web, funnel of spider, 199; of
young spiders, *207; of tri-
angle spider, *205; round, 200.

Whale, 262, 263; bowhead, 263;
right, 263; sperm, 263.
INDEX 363

Whalebone, 263. Worms, marine, *149; thousand.
White fish, 212. legged, 159.
Wildcat, 269.
Wing of bird, 62. Yellow fever, disseminated by
Wings, scales of butterflie ’, mosquitoes, 9.

281. Yellowhammer, *247.
Wolf, gray, 269. Yellow-jacket, 315; life of com-
Wolverine, 269. munity of, 316; nest of, *316.
Woodchuck, 260. Yellow-jacket, nest of queen, *317.
Wood-frog, 217. Young, care of, by batrachians,
Wood-lice, 157. 44; care of, by birds, 44; care
Wood-rat, 260; nest of, 46. of, by fishes, 42; care of, by

Worker, honey-bee, *307. mamunals, 44.
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