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Principles of economic zoology,

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http://www.archive.org/details/cu31924002844821

PRINCIPLES

OF

ECONOMIC ZOOLOGY

BY

SOR OF ZOOLOGY, STATE NORMAL SCHOOL, KIRKSVILLE, MO.

AND SCHOOL GARDEN”’

WITH 301 ILLUSTRATIONS

PHILADELPHIA AND LONDON

W. B. SAUNDERS COMPANY
1915

Copyright, 1912, by W. B. Saunders Company

Reprinted May, 1915

PRINTED IN AMERICA

PRESS OF
w. B. SAUNDERS COMPANY
PHILADELPHIA

PREPAGE

THE authors have long felt the need of one book in the
hands of the student which would give not only the salient
facts of structural Zodlogy and the development of the various
branches of animals, but also such facts of natural history—or
the life and habits of animals—as to show the interrelations of
structure, habit, and environment. For we believe that a
knowledge of both structure and life-history is necessary before
any suggestions or discoveries can be made concerning the prin-
ciples which underlie and control all animal life, including that
of man. For it is principles and their application for which we
are searching.

This book is an attempt to supply this need. It is especi-
ally designed to accompany the “ Field and Laboratory Guide”
(Part I).

For the sake of the natural history many examples have
been included. To reduce the size of the book it has been
necessary to print this natural history in smaller type, but
that in no way implies that it is of minor importance, and it is
by far the most interesting portion of the subject. The scien-
tific names need not, in all cases, be learned. They have been

used because common names are so often misleading.

iii

iv PREFACE

Much of the subject matter has been derived from our own
observation and experience, but we have made use of material
from all available sources and we have tried to give credit by
continual reference to the authorities used. That a book of
this character can never be original, everyone knows. The
scope is too great for the observations of one lifetime.

We are aware that we have fallen far short of our ideal.
But we believe the book will be of much service if followed as
suggested and used in connection with Part I. ‘If a better
system is thine, impart it frankly. If not, make use of mine.”

THE AUTHORS.
IX1RKSVILLE, Mo.

CONTENTS

BRANGH PROTOZOA dein Sa. RS Ae) Ae a Ge oa a sawed LAM TAOS 1

Class I. Rhizopoda, 1.—Class II. Mastigophora, 4—Class III.
Sporozoa, 4.—Class IV. Infusoria, 5.

BRANCH PORTPERAL 6 ccccc504c0 G4 ee Oe eased ds eden e cma edwad 10

BRANCH ‘CO@GENTERATAL ce jo andewgte ves wav deweks Man abe woes een ek oe 17

Class I. Hydrozoa, 18.—Class JJ. The Scyphozoa, 26.—Class
IL. Actinozoa, 26.—Class IV. Ctenophora, 31.

BRANCH PLATYHELMINTHES.......00.00000 0 ccc eee eee cece ne 34

Class I. Turbellaria, 34.—Class II. Trematoda, 35.—Class III.
Cestoda, 37.—Class IV. Nemertinea, 39.

BRANCH NEMATHELMINTHES..... 00.00.0000 cece ee cece cee eeeaee 41

Class I. Nematoda, 41.—Class II. Acanthocephala, 44.—Class
Ill. Chetognatha, 44.

BRANCH TROCHELMINTHES.......... 000 cece eee e eee e eee eeees
Class I. Rotifera, 46.—Class II. Dinophilea, 47.—Class III.
Gastrotricha, 47.

BRANCH MOLLRUSGCOIDA tis igs os Saud Sons Saige ead oe aaetteuadet ows 48

Class I. Polyzoa, 48.—Class II. Phoronida, 48.—Class III.
Brachiopoda, 48.

BraNncH ECHINODERMATA. .... 2.0.00 e cece teeter eens 50
Class I. Asteroidea, 54.—Class II. Ophiuroidea, 56.—Class III.
Echinoidea, 58.—Class IV. Holothuroidea, 60.—Class Y.
Crinoidea, 62.

BRANCH ANNULAT Ag o3 cee as ee sedges Geared nen dao een way ke 65

Class I. Cheetopoda, 65.—Class II. Gephyrea, 69.—Class III.
Hirudinea, 69.

BRANCH M@LRUSCA ce i553 25845 50 St 3 Gus Sohaidied Gawen ac eeeand EES 72
Class I. Pelecypoda, 73.—Class II. Gasteropoda, 81.—Class III.
Cephalopoda, 84.

v

vi

CONTENTS

BRANGH: ARTHROPODAG 65s co5 cidade 8 o0 hone REO REESE hakG Bas

BraNcH CHORDATA

Class I. Crustacea, 90.—Sub-class Entomostraca, 90.—Order
I. Phyllopoda, 90.—Order II. Ostracoda, 90.—Order III. Cope-
poda, 91.—Order IV. Cirripedia or Barnacles, 91.—Sub-class
Il. Malacostraca, 92.—Order I. Phyllocardia, 93.—Order II.
Decapoda, 93.—Order III. Arthrostraca, 102.

Class II. Arachnida, 103.—Order I. Scorpionida, 103.—Order
II. Phalangidea, 104.—Order III. Araneida or Spiders, 104.—
Order IV. Xiphosura, 110.

Class III. Myriapoda, 111.—Order I. Chilopoda, 111.—Order
II. Diplopoda, 112.

Class IV. Insects, 112.—Order I. Aptera or Thysanura, 126.—
Order IJ. Ephemerida, 127.—Order III. Plecoptera, 128.—
Order IV. Odonata, 129.—Order V. Isoptera, 131.—Order VI.
Orthoptera, 132.—Order VII. Hemiptera, 140.—Order VIII.
Coleoptera, 148.—Order IX. Diptera, 153.—Order X. Siphon-
aptera, 161.—Order XI. Lepidoptera, 162.—Order XII. Hymen-
optera, 174.

Sub-phylum and Class I. Adelochorda, 191.—Sub-phylum and
Class II. Urochorda or Tunicata, 192.—Sub-phylum and
Class III. Acrania or Amphioxus, 194.

Sub-phylum, IV. Craniata or Vertebrata, 195.—Class I. Cy-
clostomata, 195.

Class II. Pisces, 196.—Sub-class I. Elasmobranchii, 206.—
Sub-class II. Holocephali, 207.—Sub-class III. Dipnoi, 208.—
Sub-class IV. Teleostomi, 209.—Order I. Crossopterygii, 210.—
Order II. Chondrostei, 210.—Order III. Holostei, 210.—Order
IV. Teleostei, 211.

Class III. Amphibia, 221.—Order I. Stegocephala, 228.—Order
II. Apoda or Gymnophiona, 228.—Orddr III. Urodela or Cau-
data, 229.—Order IV. Anura or Ecaudata, 233.

Class IV. Reptilia, 236.—Order I. Rhynchocephalia, 238.—
Order II. Ophidia, 239.—Order III. Lacertilia, 243.—Order IV.
Chelonia, 248.—Order V. Crocodilia, 253.

Class V. Aves, 258.—Division A. Ratite, 278.—Dirision B.
Carinate, 281.—Watcr Birds: Order I. Pygopodes, 281.—Order
II. Longipennes, 282.—Order III. Tubinares, 283.—Order 1V.
Steganopodes, 284.—Order V. Anseres, 285.—Order VI. Odon-
toglosse, 286.—Order VII. Herodiones, 286.—Order VIII.
Paludicole, 289.—Order IX. Limicole, 290.—Land Birds:
Order X. Galline, 291.—Order XI. Columba, 292.—Order
XII. Raptores, 204.—Order XIII. Psittaci, 297.—Order XIV.
Coccyges, 297.—Order XV. Pici, 298.—Order XVI. Machro-
chires, 300.—Order XVII. Passeres, 300.

iss

CONTENTS vil

PAGE
Class VI. Mammalia, 311.—Order I. Monotremata, 319.—
Order II. Marsupialia, 320.—Order III. Edentata, 323.—Order
IV. Nirenia, 325.—Order V. Cetacea, 326.-—Order VI. Ungulata,
329.— Order VIL. Rodentia or Glires, 350.—Order VIII. Car-
nivora, 356.—Order LX. Insectivora, 366.—Order X. Chirop-
tera, 368.—Order XI. Primates, 372.
THEORIES OF DEVELOPMENT. ........00-00000 00000 cee vee eee 382
GLOSSARY e Gi pho he OER EAE apy ch RN Gh n Bn DE woo 395

“There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.’

SHAKESPEARE.

PRINCIPLES OF
ECONOMIC ZOOLOGY

BRANCH PROTOZOA

THE animals of this branch are one celled and microscopic,
or very small. These cells may unite, but as the union is not
organic, it is said to form a colony, and not an individual animal
as is the case in the higher forms. A colony may consist of a
few cells, as in Gonium, or of many cells, as in Volvox.

Since protozoans are so minute and their soft protoplasmic
substance is so easily dried up, they are usually aquatic, but
some forms are parasitic, while others, as Ame'ba terric’ola, are
terrestrial, but these live or remain active in moist places only.
Protozoans are most abundant in salt water, or in stagnant pools
of fresh water, and are found in almost all parts of the globe.

Since, by reason of their simplicity, protozoans are adapted
for living where other animals could not exist, they are supposed
to be the oldest. or first animal life, and it is believed that they
existed in the Archean time.

Numbers.—There are many thousands of species of these
protozoans, each species differimg from all others in some
detail, yet all agreeing in their unicellular simplicity. Only a
few of the typical forms can be mentioned.

CLASS I. RHIZOPODA

The lowest class, or Rhizop’oda, is represented by the Ameba
(Fig. 1). It is an irregular mass of colorless, semifluid, or jelly-
like living protoplasm destitute of a cell wall. There is no dis-

1

2 BRANCH PROTOZOA

tinct line between the clear outer homogeneous layer, or ecto-
plasm, and the inner granular substance, the endoplasm. Within
the endoplasm is the nucleus, a small, round, denser mass.
Sometimes the contractile vacuole, a clear sphere of liquid and
gas, appears, increases in size, then contracts, and disappears,
and a new one is formed. This is supposed to aid in respiration

Fig. 1.—Ameba polypodia in six successive stages of division. The dark
white-edged spot in the interior is the nucleus. (Schulze.)

and in carrying off the waste products formed by oxidation,
such ax carbon dioxid.

Motion and Locomotion.— Under the microscope the amaba
may be identified by its movements. The body surface will be
seen to protrude or rather flow out at one or several points,
forming irregular lobes, called false feet, or pseudopodia, which

RHIZOPODA 3

may be contracted, or the whole body protoplasm may flow
along after them, thus producing locomotion as well as constant
change of form.

According to the experiments of Professor H. 8. Jennings,
particles attached to the ectoplasm move forward on the upper
surface, disappear over the anterior edge, and, as the proto-
plasm flows along, appear again at the posterior end, to repeat
the circuit, showing that this locomotion is a sort of ‘rolling
process.”

Feeding.—As the amceba flows or rolls along, if it comes in
contact with a particle which is unfit for food, it passes by or
over it, but if the particle is fit for food, it flows about and en-
velops it, and forms the so-called food vacuole. As this food
vacuole moves along the endoplasm, the digestible part of the
food disappears in digestion, while the indigestible portion is
left behind as the protoplasmic body moves along.

Multiplication in the case of the Ameba is by binary division
or fission and by sporulation. This becomes necessary, since
the entire animal is but a single cell, and all the functions for
the whole animal must be performed by this one cell. Hence,
it must remain exceedingly small, so the nucleus, as well as the
body substance, divides into two halves, and two individuals
result.

Encysting.—Under unfavorable environment, such as drouth,
the Ameba contracts into a tiny sphere, becomes encysted or
encased in a horn-like membrane, and remains in a dormant
condition until favorable environment returns to it, or it is trans-
ported by the wind or carried by other animals—in the dirt
which has clung to them—to a favorable environment, where
it bursts its cyst and resumes active life.

The Radiola’ria are marine Rhizopoda which have their pseudopodia
arranged like rays. Many of these forms possess a silicious shell or skele-
ton, and myriads of these shells are found in rocks of various geologic
ages. One type reproduces by swarm spores, the original nucleus dividing
into hundreds of daughter-nuclei.

The Foraminif’era are Rhizopoda whose fresh-water forms have chitinous
or silicious coverings, while the typical members, which are marine, have
caleareous shells. When the animal dies the shell sinks to the bottom of
the ocean. Such multitudes have existed that vast formations of chalk
or limestone rock have been made by their shells. The stone of the Pyra-
mids is said to be composed of fossil Foraminifera.

4 BRANCH PROTOZOA

It is suid that in the bodies of some Radiolaria are found unicellular
Algee, or microscopic plants, which furnish, even in this low stage of life,
an example of symbiosis, or the living together of different kinds of organisms
for mutual benefit.

CLASS II. MASTIGOPHORA

The Eugle’na is a representative of the second class of Pro-
tozoans (Mastigoph’ora). It has a more fixed arrangement
of parts than the Ameba. The cell is surrounded by a delicate
membrane perforated at the blunt anterior end by a funnel-
shaped mouth through which the food passes into the body sub-
stance. From the base of this mouth the protoplasm extends
out in a long flagellum which, by its lashing, propels the body
forward, and produces currents of water which bear food into
the mouth. Back of the mouth is a tiny pigment spot beside a
clear space which is sensitive to light.

CLASS III. SPOROZOA

This class consists of parasitic protozoans. The Gregari’na
is parasitic in the intestines, reproductive organs, or, rarely, in
the body cavity of invertebrates, such as crayfish, insects, and
worms. It absorbs liquid food from its host and has no mouth
nor pseudopodia. One or two individuals become encysted and
then break up into a number of minute portions called spores.

The Hemosporid’ia are sporozoans which live in the blood-corpuscles of
vertebrates. In man they are the germs which produce malaria. The
malaria-producing protozoans spend part of their life in man and part in a
certain genus of mosquito -lnoph’eles). When this mosquito sucks the
blood of a malarial patient the germs are taken into the stomach of the
mosquito. ‘ After fertilization the odsphere wanders into the intestinal
wall of the mosquito, grows larger, encysts, and produces many sporo-
blasts, which in time form many sporozoites.” These pass out with the
saliva of the female Anoph'eles as it ‘ bites” another person, and thus the
germs of malaria are transferred to his blood, where, under proper condi-
tions, they multiply rapidly, and fever results. It is evident that the bite
of this mosquito does not cause malaria unless the mosquito is itself in-
feeted with the germs.

Yellow fever is believed to be caused by another sporozoan carried by 1
‘different genus of mosquito (Slegomy’ia). ,

INFUSORIA 5

CLASS IV. INFUSORIA

The fourth class of protozoans is the Infuso’ria, of which
the Paramecium, or “slipper animalcule,” is a type (Fig. 2).
It is somewhat cylindric in form and is surrounded by a cuticle
perforated with minute openings, through which the proto-
plasm projects in the form of short hair-like structures, called
cilia, which are the organs of locomotion.
On the ventral surface of the Paramcecium
is a groove which runs backward and
inward into a short tube or gullet. Both
the tube and the gullet are lined with
vibrating cilia which cause currents of
water. These currents carry the food into
the inner end of the gullet, where it is
pushed by occasional constrictions into the
soft endoplasm and carried about in its
movements as a food vacuole. The un-
digested particles are cast out at a fixed
point in the cell wall, but it is not per-
manently open, so it is not easily recog-
nized. The Paramcecium is supplied with
two coiled threads which may be used
as organs of defense. The Paramcecium
has two nuclei, one, the macronucleus,
supposed to be the seat of all vital func-
tions, and the other, the micronucleus,
which controls the reproduction. The . Fi: 2.—Parame-

: : cium aurelia. In the
Paramcecium reproduces by fission, both center may be seen
nuclei being divided, but conjugation one of the nuclei, and
also is manifested. In conjugation, oe Sees
two Parameecia unite temporarily, ex- Verworn.)
change a portion of the micronuclei,
and perform other processes; they then separate, and continue
more actively the process of transverse division or fission.

While these examples are only a few of the thousands of
species and of the countless myriads of individuals of proto-
zoans, yet, if carefully studied, they teach many things.

Protoplasm.—Living protoplasm is the active substance of all
living organisms. All the forces or conditions which tend to

6 BRANCH PROTOZOA

Fig. 3—Organisms very abundantly found in common sea-water that
has stood a few days in an open shallow dish: a, Acineta with embryo
budding off; b, resting spores of alga, with bacteria; c, Chilodon; d, small
Navicula; c, Cocconeis; f, larger species of Navicula; g, heliozoan, with
two entrapped infusoria; h, germinating alga cells; 7, small colony of bac-
teria in zodglea stage with small flagellate infusoria near by; &, flagellate
infusorian; #7, infusorian Afesodinium; n, ciliate infusorian; v, Vorticella,
with small portion of its stalk. (Bull. U.S. F.C., 1895.)

4

INFUSORIA 7

cause response or reaction in living protoplasm are called
stimuli. The principal stimuli! may be classed as chemical
stimuli, differences in temperature, light, contact, electricity,
and gravity. Protozoans possess: (1) Irritability, that property
of living protoplasm which gives it power to respond to stimuli;
(2) automatism, the power of movement, or of changing the form.

Locomotion.—Protozoans move by means of pseudopodia,
cilia, or flagella. Some forms, as the Vort/cel'la, are fixed, and
can move only by the contractility of their stalks or stems.

Nutrition —The food of protozoans is composed of whatever
minute organisms or fragments of organic matter they are
able to obtain in the water. The parasitic forms, of course,
simply absorb nutriment from the liquids of the host. The proc-
ess of nutrition in the simplest protozoan consists in wrapping
or, more correctly, flowing itself about the particle of food,
absorbing the nutriment needed, and rejecting what it cannot
use. Thus we see that it has the power of selective absorption,
or digestion.

Circulation is brought about by simply changing the form of
the body mass, thus changing the position of the absorbed
nutriment in the one-celled body.

Assimilation, or the making of this absorbed material into
its own body substance, next takes place, and, as a consequence,
growth. The using up of assimilated material for heat or
motion (energy), or metabolism, also takes place.

Respiration, or the taking in of oxygen and the giving off
of carbonic acid gas and other wastes, is effected by the absorp-

1The reactions (orientation) of animals in response to these various
stimuli are called tropisms; the response to chemical stimuli is called
chemotropism; to heat, thermotropism; to light, phototropism; to contact,
thigmotropism; to electricity, electrotropism; to gravity, geotropism, and so
on. Loeb and others claim that the movements of the lower forms and
many of those of the higher forms are purely physical and chemical reac-
tions, just exactly as those known to us in the inorganic world. H. 3.
Jennings, who is another very careful investigator, asserts that his inves-
tigations show “ that in these creatures their behavior is not, as a rule, on
the tropism plan—a set, foreed method of reacting to each particular agent
—but takes place in a much more flexible, less directly, machine-like way
by the method of trial and error. . . This method lcads upward, offer-
ing at every point opportunity for development, and showing even in the
unicellular organisms what must be considered the beginnings of intelli-
gence and of many other qualities found in higher animals.”

Py &

8 BRANCH PROTOZOA

tion of the one and the throwing off of the other through the
surface.

Excretion takes place through the surface or through the
contractile vacuole, there being a definite point at which the
waste is ejected in the more advanced forms, such as the
Paramecium and the Vorticella.

Multiplication While these life processes are going on, the
animal grows or increases in size. This size must necessarily
be very limited, for only small animals could live in this primi-
tive way; hence, when the protozoan has reached a sufficient
size, it divides into two complete halves, each half containing
its share of the original cell-nucleus, as well as of the cytoplasm
or protoplasmic cell body. This cell division, or the multiplica-
tion of individuals, is called fission. After simple fission has
taken place for many generations the fusion of two individuals,
or conjugation, in which the nucleus of one individual is broken
up and fused with that of the other, occurs. After this fusion,
the process of fission continues, in which each new individual now
contains a portion of the two parent nuclei which were fused
in conjugation, instead of one parent nucleus as before con-
jugation. This surely contains a suggestion of sexual mul-
tiplication, though the conjugating cells may appear exactly
alike. However, instances are given in which the individuals
differ in size, the ‘‘males”’ being smaller and more mobile.
Also we see, not exactly “alternation of generations,” but, at
any rate, alternation of methods of reproduction.

Animal Mind.\—Of the mental life of the protozoan little is
known. If the rudiments of future complex animals is fore-
shadowed in the protozoan, why may we not recognize the fact
that here, too, is found the merest suggestion of the mental life
as well?

It has been abundantly demonstrated that protozoans possess
irritability and contractility. It has been shown that they are
sensitive to touch or contact, and, indeed, can discriminate
between a hard substance and a softer substance suitable for
food, as well as to recognize their kind by contact.

1 Mind is here used in the biologic sense, and is the “sum total of all
psychic changes, actions, and reactions.’’—Jordan and Kellogg's ‘‘ Evolu-
tion and Animal Life,” p. 448.

INFUSORIA 9

Weir, in his ‘f Dawn of Reason,” tells of observations with an
Actinoph’rys, inwhich it was seen to discriminate between starch
grains and uric-acid crystals.

Protozoans are also known to be responsive to heat and light.
Werr also states as his opinion that all animals can cistinguish
day from night. The question remains as to whether or not
this is ascertained by sight. However this may be, there can
be absolutely no vision, because there is no mechanism for it.

Importance of Protozoans.—(1) They furnish, either directly
or indirectly, food for all higher forms of life. (2) They are
scavengers of decayed organic matter. (3) By their countless
numbers throughout the ages, vast formations of chalk or lime-
stone have been made. Myriads of them are still sinking to the
bottom of the ocean as Globigeri’na ooze or fadiolarian ooze.
Since these animals are aquatic, geologists know that wherever
these vast formations are found, there was once the sea. (4)
Some of them are parasitic in the lower animals and in man,
causing diseases which are ofttimes widespread and serious.

Classification —(Adapted from Parker and Haswell):

Class, Examples.
I. Rhizdp’oda. Ame’ba, etc.
II. Mastigdph’ora. Euglé’na, Vol’vox.
III. Sporozd’a. Grégari’na, ete.

IV. Infusd’ria. Paramce’cium and Vorticél’la.

BRANCH PORIFERA

ALL animals except the Protozoans are multicellular and are
classed as Metazoa.

Differentiation.—In all we find, to a greater or less degree,
division of labor among the cells, or the differentiation into tissues
and organs for special functions.

Reproduction.—True sexual reproduction is the charactcristic
method among Metazoans.

Porifera——These aquatic, many-celled animals were formerly
considered as plants. Indeed, they look like seaweeds among
the rocks at the bottom of the sea. Most of the sponges are
marine, but there are a number of fresh-water forms.

Fresh-water sponges are widely distributed, and are attached
to weeds ‘or submerged objects along the margins of clear
springs or ponds.

Sponges vary in color from a greenish hue to red, brown, or
flesh color. All of the soft parts, as well as the skin or covering,
is gone from the commercial sponges.

Their shape, as is scen in the sponges of commerce, is irregu-
lar even in the same species; it varies with the environment, in
order that the sponges may adapt themselves to the surface
to which they are attached or the depth and currents of the
water. Their size varies from a fraction of an inch to two or
three feet in diameter.

Structure——The body of the Porifera consists of many cells
arranged in two layers, an inner, or endoderm, and an outer, or
ectoderm. There is a middle undifferentiated layer (aesoglea).
The simplest sponge is cylindric or vase shaped (Fig. 4),
while others, more complicated, consist of a system of branch-
ing tubes. At the free end of each is a small opening, the
osculum, or exhalant orifice, while the walls of the eylinder are
perforated by exceedingly minute rnrhalant pores. The ecto-
derm consists of flattened cells, which are also found to extend
for a short distance inside the osculum, while the rest of the tube

10

MULTIPLICATION

11

is lined with a single layer of peculiarly shaped columnar cells,

each possessing a flagellum.

The skeleton is developed in the middle layer and may
consist of silicious or of calcareous spicules of a great variety of

form, sometimes they are anchor shaped,
and again others are club shaped, spear
shaped, or cruciform. The so-called glass
sponges sometimes have beautiful silici-
ous skeletons. In other cases the skele-
ton consists simply of fine, flexible, inter-
woven fibers of tough, horny spongin.
It is the skeleton, denuded of the flesh,
or sarcode, that covers it in life, which
forms the commercial sponge. A few
sponges have no skeletons.
Nutrition.—There are no organs of
digestion, circulation, or respiration in
the sponge. The food consists of micro-
scopic plants or animals, or of minute
particles of organic matter floating in
the water. The food-laden water enters
through the inhalant pores and is carried
by the movement of the flagella through
the canals or paragastric cavities. The
food as well as oxygen is taken up by
the cells lining the canals and by the
ameboid cells. The waste is carried out
by the outgoing currents of water, which
empty through the osculum, or, if the
sponge is complex, the oscula.
Locomotion.—At first the larval sponge
is free swimming, by means of cilia.
It soon becomes “fixed to some stone

Fig. 4—A_ simple
sponge (Calcolynthus
primigentus) with part
of outer wall cut away.
(After Hackel.)

or other object or animal, and assumes the fixed ways of its

ancestors.

Multiplication—(1) Asexual, by external budding and the
consequent formation of a united colony, or by internal gem-
mules; (2) sexual, thus insuring the perpetuation of the species.
Sponges are hermaphroditic, that is, both the male elements

12 BRANCH PORIFERA

(sperm cells) and the female elements or eggs (ova) are con-
tained in the same individual (Fig. 5). It is from the union
of a sperm cell with an ovum that the new individual sponge
is developed. The sperm cells and the ova rarely mature at
the same time in the same individual. Hence, the ova in the
canals of one sponge are fertilized hy the spermatozoa of an-
other sponge, which are carried to them by the afferent currents
of water in the canals, thus insuring cross-fertilization. The
eges are retained in the canals until the blastula stage of their

Fig. 5.—First stages in embryonic development of the pond snail
(Lymiucus): a, Weg cell; 6, first cleavage; ¢, second cleavage; d, third cleay-
age; ¢, after numerous cleavages (Morula): f, blastula Gin section); 4,
gastrula just) forming (in section); #, gastrula completed Gin’ section).
(After Rabl.) This may be taken as a type of the earliest development of
all many eelled animals (Metazoa). (rom Jordan and Kellogg, ‘* Animal
Life,” D. Appleton and Co., Publishers.)

development is reached, then they are set free and pass
out at the exhalant opening or osculum. The fresh-water
sponges (sponyilla) bear small, seed-like bodies called gemmules
toward the approach of winter. The parent sponge dics, the
gemmules remain dormant until the next spring, when the rising
temperature calls them to renewed life. They grow into
mature spongilla, bear other gemmules, and thus the life-
history of their race is repeated.

Animal Mind.Sponges have no well-marked nerve-cells,
though the simplest elements of both nerve and musele have been

PROTECTIVE RESEMBLANCE 13

described as belonging to them. It is evident that the sponge
possesses irritability and contractility. It has the instincts of
self-preservation and of the perpetuation of its species. No one
ean correctly interpret the psychologic phenomena of any
animal until he has passed through the same psychic phenomena
as that animal, and then become a man with the memory of
these experiences and what they signified to that animal. Since
we cannot do that, we must be content to infer the significance
of certain biologic phenomena from comparison with our own
experiences.

Environment.—As has been said, sponges are greatly in-
fluenced as to their shape by the objects to which they are at-

Fig. 6.—A young sponge. (After Burnet.)

tached and by the depth and currents of the water. They are
much more nearly uniform in deeper waters. The plastic
sponge well illustrates the influence of gravity (geotropism)
upon an animal. It also shows rheotropism.

Protective Resemblance.—Their protective resemblance is
exceedingly good. They look so much like the seaweed and
other aquatic vegetation that they are well concealed from
the animals which prey upon them, such as worms, crustaceans,
mollusks, and other marine invertebrates. Their tough, horny
texture and their silicious or calcareous spicules are also a
means of protection. Their characteristic odor, said to re-
semble garlic, makes them distasteful to fishes.

1 See Glossary.

14 BRANCH PORIFERA

Symbiosis.—Examples of symbiosis are found among them,
as that of the sponge and the crab. The sponge attached to the
crab is carried about by it and given better opportunity of ob-
taining food and oxygen, while the crab, in turn, is concealed
from its enemies by the sponge. In the fresh-water sponge, a
green alga sometimes grows, giving the green cclor to the mass.

Various small marine forms are found in the sponges, giving
good examples of commensalism. Sponges are never parasitic.

Fig. 7—Spongers at work. The “sponge hook” is a three-toothed
curved hook attached to a pole, the length of which varics with the depth
of the water. The sponge-glass is a common water-pail with the bottom
knocked out and w pane of window glass put in its place. It is used for
seeing below the surface where the water is disturbed by ripples. (Cobb,
in Circular 535, U. 8. F. C., 1902.)

“

Use.—They are of use as food for other animals, and their
skeletons form a very useful article of commerce.

The sponges of shallow water are obtained hy men in boats,
with a dredge or a long-handled hook or rake (Fig. 7); those of
the deeper waters, by divers. They are then exposed to the
air for a time and then heaped up in water again in tanks

CLASSIFICATION 15

provided for them, where they decay. The animal matter
in them is “beaten, squeezed, or washed out,” and their
skeletons sent to market (Fig. 9).

Geographic Distribution.—Fresh-water sponges are found
in streams and lakes in all the continents. Marine forms
are found in all seas and in all depths, from the shore between
tide-marks to the deepest abysses of the ocean. They are most
abundant in tropical waters.

Geologic Distribution.—Silicious sponges were not uncommon
in the Cambrian Period, and are found in the formations from

aia

Fig. 8.—Bringing sponges from the vessels to sponge wharf at Key West.
(Report U.S. F. C., 1902.)

that time on. They were abundant in the Jurassic and very
abundant in the Cretaceous of Europe; none have been found
in that of America.

Important Biologic Facts.—Even in this low type there is a
differentiation of certain cells for certain purposes, as the
skeletal and reproductive cells. True sexual reproduction ap-
pears for the first time in the Porifera. Conjugation was noted
in the Paramcecium.

Classification.—Sponges are of three kinds: (1) The calear-
eous sponges, containing much lime. They are of little or

16 BRANCH PORIFERA

no commercial value. Example, Grantia. (2) The silicious
sponges, in which the skeleton is largely silica. Example,
Euplectel'la. (3) The horny sponges of commerce. Euspongia
group. To this group belong the half-dozen species of Florida
and the Mediterranean and the Red Seas. Our American sup-
ply comes principally from Florida and the Mediterranean Sea

"g E = a

Fig. 9.—.\ sponge auction at Anclote. (Report U.S. F.C., 1902)

from water not exceeding 30 fathoms deep. [cxamples of this
group are Spongia, and the fresh-water forms of the genus
Spongilla,

Most zoélogists make but one class of porifera; others, two
Classes :

I. Calea’rea.

Il. Non-calea’rea.

BRANCH C(HLENTERATA

Tuts branch comprises our fresh-water Hydra, and a few
allies, and the marine forms, jelly-fishes, corals, and sea-ane-
mones. This branch finds representatives from the shore line
and the surface to the profound depths of the ocean.

The body, which is usually radially symmetric, consists es-
sentially of a two-layered sac, which is open at one end and
closed at the other, and in which there is a simple or branched
gastric cavity. The outer layer is called the ectoderm; the
inner layer, the endoderm, and a gelatinous non-cellular layer
between them, the mesoglea. Some ccelenterates are soft-
bodied, others secrete a calcareous or limy substance called
coral. Around the free open end of the sac-like body are a
varying number of tentacles.

Nettle Cells.—Stinging or nettle cells are characteristic of
this branch, except in Cetenoph’ora, where they are replaced
by adhesive cells. These stinging cells, which are especially
abundant on the tentacles, contain a fluid, and a spirally wound
thread provided with barbs, which, when the animal is disturbed,
are discharged into the body of the intruder, paralyzing it. It
is then seized by the tentacles and drawn into the mouth.

Size.—Ceelenterates vary in size from the little fresh-water
hydra, a fraction of an inch in length and of the diameter of a
pin, to the giant jelly-fishes, as the Cya’nea, which sometimes
reach 7 or 8 feet in diameter and have tentacles more than 100
feet long.

Locomotion.—Some members of this branch are free, as the
jelly-fishes; some are permanently fixed; as the Corals, while
some, as the Hydras, are temporarily fixed, moving from one
position only to adhere to another, and thus making slow pro-
gression.

Multiplication is both sexual (by eggs) and asexual (by
budding).

Origin.—They are of ancient origin, being abundant in the
Cambrian Period.

2 WW

18 BRANCH CQ@RLENTERATA

CLASS I. HYDROZOA

In this class are found the worldwide fresh-water Hydras and
the marine Hydroid Colonies, such as Campanula’ria or Obe’lia.

The Hydras are small fresh-water Hydrozo’a from ~ to £ or
possibly 4 inch in length. They may be white or colorless, or
green or brown.

The body is a simple cylinder (Fig. 10) or sac, closed at one
end, and near the other surrounded by six or eight tentacles,

Fig. 10.—Hydra: Longitudinal section of animal, showing m, mouth;
t, tentacle; d, digestive cuvity; 6, bud; s, spermary; v, ovary; cc, ectoderm;
en, endoderm. Magnified. (From Dodge’s “ General Zoology,” American
Book Co., Publishers.)

above which is the conical hypostome, at the apex of which is the
mouth. The muscular fibers of the ectoderm extend lengthwise,
while those of the endoderm extend around the body.' If
disturbed, the Hydras protect themselves by withdrawing into
a tiny sphere, while the tentacles contract until they look like
so many small buds. The endoderm has flagellate cells lining
the gastrovascular cavity.

1 Hertwig’s “Manual of Zodlogy,” Kingsley, p. 230,

HYDROZOA 19

The food is obtained by the viscid tentacles, which, when the
Hydra is undisturbed, are extended (as is usually the body),
ready to grasp the prey, for this tiny animal is carnivorous,
feeding upon small organisms, usually crustaceans. There are
nettle cells, or nematocysts, in the ectoderm of the tentacles.
When an animal comes in contact with a tentacle, the nemato-
cysts near the point touched throw out stinging threads which
partially paralyze the animal by the fluid which they discharge
into the wound they have pierced. The tentacles then pass
the prey to the mouth, which opens into the gastrovascular
cavity, in which digestion is carried on and into which the
wastes are gathered and thrown out through the only opening,
the mouth. The Hydra, by its wide-open mouth and envelop-
ing lips, often takes in organisms much larger than itself.

Nerve-cells, sex-cells, and nettle-cells are situated in the
ectoderm.

Multiplication in the Hydra is both sexual and asexual.
It reproduces by budding, but as the buds mature they become
detached, so that no permanent colony is formed. It also
reproduces by eggs, the animal being hermaphroditic, that. is,
the reproductive organs of both sexes are found in the same indi-
vidual. Near the base of the tentacles are found the spermaries
from which the sperm cells are discharged into the water; the
ovaries are situated farther down, near the lower end of the
body. The eggs are cross-fertilized, that is, fertilized by the
sperm cells of another individual. After fertilization the ova
remain in the ectoderm for some time, when they become en-
cysted in spiny cysts, drop off into the water, and sink to the
bottom. They lie here till the following spring, when they
break their casing and come forth as minute Hydras. In the
encysted condition they are able to withstand cold and drouth,
thus insuring the perpetuation of the species. Hydras also have
the power of regenerating the whole body from a part in case of
injury.

Locomotion—The Hydra is temporarily fixed by adhering
to the submerged stems of water plants by means of a sticky
secretion from the closed end of the tube. It can detach itself,
and, by grasping with its tentacles, can pull itself up and again
attach the end of its tubular body to an object. By this cater-

20 BRANCH CQSLENTERATA

pillar-like looping it is able to change its position or perform
slight locomotion.

Dispersal While the mature Hydra has very limited powers
of locomotion, or direct dispersal, its offspring may be widely

Fig. 11.—A, Part of the colony of Bougainiil’lea mus’cus, one of the com-
pound Hydrozoa, of the natural size. B, Part of the same enlarged: p, A
polypite fully expanded; m, an incompletely developed reproductive bud;
m’, a more completely developed reproductive bud; f, coenosare with its
investing periderm and central canal. C, A free reproductive bud or medu-
siform gonophore of the same: n, Gonocalyx; p, manubrium; c, one of the
radiating gastrovascular canals; 0, occllus; r, velum; é, tentacle. (After
Allman.)

separated from the parent through /ndirect dispersal, or the
drifting about of the encysted eggs by means of currents and

HYDROZOA 21

waves, or the transporting, by the same means, of the débris
to which they are attached in later life.

Symbiosis is exemplified by Hyd’ra vir'idis, or the green
Hydra, the color probably being due to the presence of small
green alge.

Another species found in Russia, Polypo’dium hydrifor’me,
of which little is known, is parasitic on sturgeon eggs.!

A Hydroid Colony (Fig. 11).—Suppose a hydra-like animal
to bud and branch until it looked like a tiny bushy shrub. This
will give you some idea of these plant-like hydroids. These
hydra-like animals, or polyps, are connected by a system of
tubes, the common stem or axis bearing many individual zodids.

Fig. 12.—Obe’lia flabella’ta. (Hincks.) Fig. 13.—Obe'lia commissura'lis.

Obelia (Figs. 12, 13) is a good representative of such colonies.
The axis is made up of a creeping horizontal portion and of
vertical axes. The short, alternate, lateral branches of these
axes bear zodids at their extremities, or, again branching, the
polyps or zodids are borne on the second set of branches. When
these zoédids are immature, they are little, club-shaped enlarge-
ments. When mature, the polyps are surrounded proximally by
a little glassy, protective cup, the hydrotheca, and distally bear
about a score of tentacles. These are the nutritive zodids,
for division of labor is found here. The tentacle-bearing indi-
viduals procure the food, and since the tubes are all hollow

1 Hertwig’s ‘‘ Manual of Zodélogy,” Kingsley, p. 241.

22 BRANCH CQSLENTERATA

and connected, the whole colony shares the food thus supplied.
When disturbed the polyp withdraws into the hydrotheca for
protection.

Blastostyles—But while the majority of the members of this
colony are hydra-like, tentacle-bearing polyps which reproduce
by budding only, and can enlarge the original colony, they
have no power of directly producing a new colony in a more
favorable position. There is, therefore, another set of individ-
uals (see Fig. 11). These, while forming a part of this tubular
colony, are modified in their form for a particular function.
They are situated toward the proximal region of the colony and
are long, cylindric bodies, known as blastostyles, each of which is
enclosed in a transparent case, the gonotheca. These are the
reproductive zodids, and bear small lateral circular buds called
medusa buds, which, as they mature, become detached and pass
out through an opening now formed at the end of the gonotheca.

Alternation of Generations.—These medusa buds are sexual
and diecious, 1. e., the sexes are separate, one individual producing
the ova and another the sperm cells. After fertilization, which
takes place in the water, the egg develops into a simple, free-
swimming ciliated larva, the planula, which soon attaches itself
to some object, develops into a polyp, and, by budding, forms
anew colony. This regular reproduction by budding, and then
by eggs, and then by budding again is called alternation of genera-
tions, or metagenesis.

Meduse.—Careful study shows that the Medusa is only a
highly developed or modified zodid. The cylindric body has
been developed into a disk or umbrella-shaped body (Fig. 14);
the long axis has been greatly shortened and is suspended be-
neath the center of the sub-umbrella, as the under surface of
the disk is called, where it takes the name of manubrium, or
“handle.” At the free end of this manubrium is the mouth,
which opens into the gastric cavity that occupies the whole
interior of the handle.

At the base of the manubrium four radial canals, equally
distant from each other, are sent out to the circular canal,
which runs around the margin of the umbrella, but within its
substance. Thus, the food taken into the mouth is distributed
to the whole animal. The whole canal system is lined by endo-

HYDROZOA 23

derm, which is ciliated. The endoderm also forms the axes
of the tentacles. There is also a layer of endoderm between the
radial canals extending from the circular canal to the gastric
cavity. Between the endoderm and the ectoderm, which
covers the convex surface or ex-umbrella, is a much-thickened
jelly-like mass of the mesoglea, while between the endoderm
and the ectoderm covering the sub-umbrella there is a thin
layer of mesoglea. The ectoderm, of course, covers the tenta-
cles, where it is well supplied with stinging cells. At the margin
the ectoderm of both the sub- and ex-umbrellas forms a narrow

Fig. 14.—1, Pela’gia panopy'ra, oral view of mature medusa. 2. The same,
side view. (Mayer, in Bull. U.S. F. C., 1903.)

fold or shelf, the velwm, which hangs down when at rest, but
draws up like a diaphragm across the bottom of the umbrella
when the bell contracts. By the forcing out of the water the
animal is forced forward, and so locomotion is effected. Around
the outside of the velum is a row of tentacles, usually four or
some multiple of four in number.

Muscles of a longitudinal character control the tentacles,
while circular striped muscles surround the sub-umbrella and
velum, and, by contracting the umbrella and velum, produce
locomotion.

24 BRANCH CQQLENTERATA

The nerve ring surrounds the margin between the circular
muscles of the umbrella and those of the velum. At the bases
of two of the tentacles of each quadrant there are sense organs.
They probably aid the medusa in determining in what direction,
with regard to the vertical, it is swimming, that is, whether it is
moving up, down, or sidewise. In other medusz the simplest
of eyes, red pigment spots, which may or may not have a lens,
are found.

The food of the medusa consists of both plants and animals.
It is very voracious and grows rapidly after leaving the colony.

"C. ws ee

Fig. 15.— Hydractin’ia polycli’na: a, Nutritive individual; b, reproduc-

tive individual; c, spiral zoéids or fighting individuals. (Bull. 455, U. 8.
F.C.)

Multiplication—After a time cither eggs or sperm cells
develop, and are set free in the water, where they unite with
those of some other medusa and develop into the tiny larval
form, which soon attaches itself and grows into a hydroid, to
bud and branch and produce again the meduse, thus repeating
the life-cycle and the reproduction by alternation of genera-
tions.

There are more than a thousand species of the class Hydrozoa. In

some forms (Tig. 15), as the Hy'dractin'ia, there are several classes of
individuals—the nutritive, the defensive, and the reproductive—with

HYDROZOA 25

the corresponding division of labor.

These Hydractin’ia live upon the

surface of the shells of sea-snails or whelks, which are inhabited by hermit

crabs, and afford another good example
of symbiosis. The Hydractinia gets
free transportation, aiding it in secur-
ing food; it also probably feeds upon
minute fragments of the crab’s food;
while the crab, in turn, is protected
from intruders by the stinging cells of
the Hydractinia. If the hydroids are
in any way torn from the shell, the crab
finds another colony, and, tearing it
loose from its supporting object, places
it upon its borrowed shell.

Millep'ora alcicor’nis is a species of
so-called hydroid “corals’’—the beau-
tiful elk-horn or stag-horn coral of
Florida. The permanent colony num-
bers thousands of individuals, which
differ in their structure according to
their division of labor. Their cal-
careous skeletons are a cuticular prod-
uct of the ectoderm.

Another order of the class of
Hydrozoa is characterized by a
closed float containing air or gas
which serves to keep the colony
vertical in the water. In the
“‘ Portuguese man-of-war ”’ (Fig.
16), found as far north as New
England, there are suspended
from the large float (3 to 12 cm.)!
peacock blue, or, in some cases,
orange in color, several kinds of
individuals; some of them, many
feet in length and armed with
nettle cells, capture the food and
bear it to the mouth-bearing or
nutritive polyps, which digest the
food and distribute it to the col-

Ie We frvecn Z =a ;

Fig. 16.—A Portuguese man-
of-war (Physalia), with man-of-
war fishes (Nomeus gronovit) liv-
ing in the shelter of the stinging

feclers. Specimens from off
Tampa, Fla. (From Jordan and
Kellogg, ‘Animal Life,” D.

Appleton and Co., Publishers.)

ony. Others, the feelers, are groups of deep blue medusoids re-
sembling bunches of grapes, while others, with swimming move-
ments, aided by the wind, drive the colony from place to place.

1 Parker and Haswell.

26 BRANCH CCHLENTERATA

CLASS II. THE SCYPHOZO’A

Jelly-fishes are soft umbrella-like creatures resembling molds
of jelly or gelatin, as one sees who picks them up along the beach,
where they have been cast ashore by the waves. Their tissues
are very watery, hence the scarcity of their fossil remains.
However, very perfect impressions of jelly-fishes are found in
the upper Jurassic Period. Most jelly-fishes are marine and
free swimming, though a few are temporarily attached. They
are most abundant in the tropics. Great schools of them are
sometimes seen. Sometimes they are phosphorescent. They
vary in size from about 4 mm., in the simple little, bell-like
Tessera, to 1 foot in the Aurelia, and 7 or 8 feet in diameter in
the Cyanea, whose tentacles sometimes reach the length of
130 feet. A small form, Gonionemus, found at Wood’s Holl,
Mass., is green and about 1 inch in diameter. It grows on eel-
grass. All are carnivorous, feeding mostly upon crustaceans,
though some of the larger ones capture fishes of considerable size.

The food is captured by the tentacles, which are suspended
from the margin of the umbrella and which are armed with
stinging thread cells.

Locomotion is effected by the flapping of the umbrella-like
body, there being usually no velum.

Minute colored ‘ eye-specks ”’ are around the rim.

Multiplication usually is by alternation of generations, but
the young medusa or ephyra, as it is called, undergoes a meta-
morphosis or change of form as it matures. In some cases the
egg develops directly into the larval medusa and there is no
alternation of generations, but simple metamorphosis.

CLASS Ill. ACTINOZO’A

This class includes sea-anemones, sea-pens, and corals.
Only the polyp form is found in this class, no medusa being
known among them. They are exclusively marine. They are
usually fixed and many form permanent colonies.

One point in their development is a step in advance of the
Hydrozoa, /. e., the development of a gullet, esophagus, or
stomodewm, the beginning of which is seen in the Seyphozoa.
The hypostome, which in Hydrozoa bore the mouth at its apex,

ACTINOZOA 27

is here inflected and forms a tube dipping down into the body
cavity, but not reaching the bottom of it. The lower end of this
tube or esophagus (which is really the beginning of the ali-
mentary tube of higher animals) corresponds to the mouth of
the Hydra, so that the tube is lined with ectoderm. The mouth
is the only external organ, and serves both for the entrance of
food and the ejection of waste. The body cavity about this
tube is divided by thin partitions into radiating spaces.

No actinozoan is microscopic. All are long lived. One in an
English aquarium lived more than sixty years.' The sea-ane-
mones and all true corals producing reefs and islands have the
number of their tentacles in multiples of six.

Nee,
ee
WIS

Neila
|

\ =s\ en
‘)

Fig. 17.—Sea-anemone (Metrid'ium). (Emerton.)

The Sea-anemones (Fig. 17).—As one gazes in wonder at
the sea-anemones in their marine home, he can scarcely persuade
himself that those beautifully colored objects, so flower-hke—
hollow cups with their petals and sepals of such wonderful tints
—are else than flowers. But he touches one, the “ sepals and
petals ” close in upon his fingers, they tingle, and he finds that
this flower-like object is an animal and that the ‘“ sepals and
petals” are tentacles. A very different appearance it makes
when the body has been drawn down close to its attachment by
the longitudinal muscles, while the circular muscles shut in the

1“ General Zodlogy,” Dodge, p. 75.

28 BRANCH CASLENTERATA

Corgi

we
Fig. 18.—Athe'lia mirab’ilis. General view of branch. View of a calice.
(Vaughan, in Bull. U.S. F. C., 1900.)

Fig. 19.—Favia fragum (Esper). View of a corallum from the side.
(Vaughan, in Bull. U.S. F. C., 1900.)

retracted tentacles until it looks like a round mass of flesh. The
tentacles ure hollow and are armed with lasso eclls, which are

ACTINOZOA 29

useful not only for defense, but for capturing crabs and small
fishes which form the anemone’s food.

Sea-anemones are solitary, that is, they form no permanent
colony. They have no true skeleton. There is no alternation
of generations. They vary in size from |} inch to 2 feet in
diameter, and, though attached, have the power of changing
their position.

The Stony Corals (Fig. 18).—The coral polyps resemble small
sea-anemones on a much-branched stem. The calcareous skele-

Fig. 20.—J/sopo'ra murica'ta forma prolif’era lam. End of branch, height
9em. (Vaughan, U.S. F. C. Bull., 1900.)

ton is secreted by the ectoderm. The branched form arises
from the continual budding and branching from a parent stem.
The different forms (Fig. 19) of coral are caused by the different
modes of budding in the various species. Corals are of various
colors and some are said to be phosphorescent.

The members of a coral colony are organically connected.
Each feeds himself, it is true, but no individual of the colony is
independent of the others.

The size varies from that of the head of a pin to 3 inch,

30 BRANCH CQ@LENTERATA

the solitary mushroom coral being sometimes of the exceptional
size of 1 foot in diameter.

These myriads of coral polyps (Fig. 20) secrete great quanti-
ties of lime, the waves break off the branches, grind them up,
mix them with sand and shells, and thus build up coral reefs
and islands of vast extent. These are confined to warm regions

Fig. 21.—A sea-fan.

about 30 degrees on each side of the equator, since coral colonies
cannot live in temperature below 60° F., and for a full luxuriance
a higher temperature is necessary.!. They are also shallow water
animals, living from the high-water-mark to a depth of not
more than 20 fathoms. They must also have salt water, hence
they cannot live at the mouth of a river.

1Scott’s “ Geology.’’

CTENOPHORA 3l

_ The Octocoral'la, or those forms which have eight tentacles, are found
in all seas, both in shallow water and at great depths. They include
the organ-pipe coral, the precious red coral (Corallium rubrum) of the Medi-
terranean Sea, and the sea-pens and the sea-fans. The mesoglea of many
octocoralla contains irregular calcareous spicules.

The sea-pens (Pennatula’cea) usually form an elongated colony. The
stem, one end of which is embedded in the sand or mud of the sea bottom,
is supported by a calcareous or horny skeleton. The distal portion is dis-
tended like a feather and bears the dimorphic polyps.

i iat

Fig. 22.—Photograph taken with the camera submerged, to show
aquatic animals in their natural environment. In the background are seen
sea-fan and branching gorgonian. (Bull. U.S. B. F., 1907.)

The sea-fans (Gorgona’cea) (Fig. 21) havea branched colonial axis formed
of horny or calcareous substance from the ectoderm, with spicules in the
mesoglea.

In some cases the skeleton formed by the spicules forms a branched
axis, as in Corallium rubrum, or it may form a “ series of connected tubes
for the individual, as in the organ-pipe coral (Tubip’ora).’”’ ‘‘ The red coral
is found only in the Mediterranean Sea at a depth of from 10 to 20 fathoms.’’!

CLASS IV. CTENOPHORA

The Cténéph’ora, or “ comb-jellies,” are so-called from
eight bands of comb-like cilia fused at their bases, which sur-
round their nearly transparent bodies. The body is non-con-

1 Parker and Haswell’s ‘“‘Zodlogy.”’

32 BRANCH CCELENTERATA

tractile, and these cilia accomplish locomotion. They are
free and single, there being no polyp stage. They are found
from the tropical to the arctic seas. They are small—from
5 to 20 mm. in diameter—and their shape varies from that of a
pear to a sac-like or ribbon-like form. They have but two
tentacles. They are hermaphroditic, multiplying by eggs.

The central nervous system is represented by a ciliated area
on the aboral pole, and is connected with a single sensory
organ.

Economic Value.—The animals of this branch are of great
use to man, indirectly, by furnishing food for other animals, and,
directly, by the formation of great beds of limestone and of
coral reefs and islands, also by forming an article of commerce
of no small value.!

“The red coral of commerce is obtained in the Mediterranean
Sea off the coast of Africa and the west coast of Italy. The price
varies according to the color. The finest rose pink in large
pieces is valued at $400 or more an ounce. The common
article brings from $1 to $1.50 an ounce.’”

Geologic Distribution—The hydrozoa are believed to be
represented by the Graptolites, which appeared in the Cambrian
Period, were numerous in the Ordovician, greatly diminished in
the Silurian, and almost extinct in the Devonian. Large
numbers of casts of jelly-fishes are found in the Cambrian rocks.’
Hydroids and true corals were important. Marine life and reefs
were formed in the Silurian Period. Corals vastly increased
in size and number in the Devonian Period, and were abundant
in the Carboniferous, contributing largely to the limestone.
Hydractinia were found in the Cretaceous Period.

Important Biologic Facts.—In the Ctenophora is found for the
first time a true middle layer of mesoderm cells.‘

In the hydroid colony is found the division of labor among
the different sets of individual zoéids and a differentiation of
structure according to their function.

1“ The fishing for the red coral (Corallium rubrum) at Naples amounts
yearly to half a million dollars.”—Kingsley.

2 Adam’s ‘Commercial Geography.’

3 Scott’s ‘ Geology,” p. 371.

4 Parker and Haswell’s “ Zodlogy,” vol. i, p. 207.

CTENOPHORA 33

Classification.—
Class. Examples.
I. Hydrozd’a. Hy’dra, Hydroid Colonies.
II. Sc¥phozd’a. Jelly-fishes.
III. Actinozo’a. Sea Anemones and Coral Polyps.
IV. Cténdph/ora. “ Comb-jellies.”

3

BRANCH PLATYHELMINTHES

Platyhélmin’thes, or Flat Worms, have three germ layers,
the ectoderm, the mesoderm, and the endoderm. They are
flattened dorsoventrally and are bilaterally symmetric. They
have no skeleton, no circulatory system, and no ccelom or body
cavity. They have an antertor and a posterior end, but rarely a
distinct head.

The nervous system is composed of superesophageal ganglia
and lateral nerve-trunks.

The excretory system consists of water-vascular tubes.
There is no anal opening.

Development is sometimes with and sometimes without a
metamorphosis.

Habitat—Some, as the liver-fluke and the tapeworm, are
parasitic; others, as Planaria, live in fresh water. Some live
in moist places or in the mud at the bottom of ponds and
streams; while others, as Leptoplana, are marine.

Size-——The parasitic forms are sometimes 30 or 40 feet in
length, while the free forms are but 2 or 3 inches in length.
These are often found under stones, and are exceedingly deli-
cate.

Protective resemblance is very great in some species, while a
few are nearly transparent.

CLASS I. TURBELLARIA

The class Turbella’ria consists principally of non-parasitic
forms which are ciliated externally. There is usually a diges-
tive cavity. The prevailing shape is leaf-form, like that of
Plana'ria. Some marine forms, however, are shaped like “a
thin ribbon with puckered edges,” others may be thickened and
band-like, as in the land planarians, while others approach the
shape of a cylinder. Locomotion is performed by the fine
vibratile cilia which cover the surface. The ectoderm contains
sensory and gland-cells.

34

TREMATODA 35

CLASS II.

TREMATODA

The class Trématé’da is comprised of worms cither internally

or externally parasitic.

Fig. 23.—The common liver-fluke
(Fasct'ola hepat’ica) enlarged to show
the anatomic characters: ac, Acetab-
ulum;c, p., cirrus pouch; 7, intestinal
ceca; m, mouth with oral sucker; ov,
ovary; p. b., pharyngeal bulb; s. ¢.,
shell gland; ¢, profusely branched
testicles; uf, uterus; va, vagina;
v.g., profusely branched vitellogene
gland. (After Stiles, 1894, p. 300.)

The body is usually thicker than that

of the turbellarians. The
form is usually — leaf-like,
though it is sometimes elon-
gated. The anterior end is
distinguished by the arrange-
ment of suckers, and, in some
of the external parasites, by
eyes.

Fig. 24——Embryo of the com-
mon liver-fluke (Fasciola hepatica)
boring into a snail—x 370. (After
Thomas, 1883, p. 285.)

The suckers are organs of adhesion and are sometimes armed

with bristles or hooks.

They are also used in locomotion, which

is a sort of looping, like that of the leech. Except in two cases
the vibratile cilia are not found on the surface.

36 BRANCH PLATYHELMINTHES

The trematodes are hermaphroditic, and the development may
be either with or without a metamorphosis.

The Liver-fluke (Fig. 23) is parasitic in sheep. The eggs pass down the
bile-ducts of the shecp into the intestine, and from there to the exterior,
when the embryo escapes by the separating of the lid, or operculum, from
the egg-shell.

The ciliated larva swims about in the water
or remains in the damp vegetation until it
comes in contact with a pond or land snail
(Fig. 24). It then bores into the body of the
snail, where it develops into a_ sporocyst
(Fig. 25), which produces rediw. These rediw
possess a mouth, a pharynx, an intestine, and
an opening for the escape of the young, which
are internally produced. According to the
season, these young are cercarie or redia,
several generations of which may follow
before the cercarie appear. The cercarie are
adapted for aquatic life.

Fig. 25.—Sporocyst of the com- Fig. 26.—F ree-swimming cercaria
mon liver-fluke from the body of a of the common liver-fluke, greatly
snail, containing redia in course of | enlarged. (After Leuckart.)
development—enlarged 200 times.

(After Leuckart.)

The cercarie (Fig. 26) escape from the snail, swim about with their vibra-
tile tails for a time, when the tails drop off and the ccercaria become encysted
ona plant. When this plant is eaten by a sheep, cow, or hog, the young
escapes from the cyst and makes its way up the bile-ducts to the liver,
where it develops into the mature worm and produces reproductive organs,
thus completing the life-cycle.

Sheep pastured in swampy places are likely to be infected by this para-
site, and wet seasons cause epidemics.

CESTODA 37

In England the annual loss of sheep killed by the liver-flukes is estimated
at $1,000,000, and it has been known to reach $3,000,000 in one year.
There have been a few cases of this parasite found in man.

CLASS III. CESTODA

A tapeworm (Te’nia so’lium) is a parasite in the intestine
of man. It is ribbon shaped (Fig. 27), being much narrower at
the attached end, the head, or scolex.

The scolex is knob-shaped and bears the organs of attach-
ment, a circle of hooks at the end, and a sucking disk or cup-
shaped sucker on each of the four sides. The attachment is
temporary.

Fig. 27.—Te'nia sagina'ta. (Eichhorst.)

Segments.—The remainder of the tapeworm, except a short
portion immediately posterior to the head, is made up of a series
of segments or proglottides, the number of which varies in differ-
ent species. In Teenia solium there are about eight hundred and
fifty segments, while in the smaller species there are three or four
hundred, and in the larger species, several thousand. These
segments or proglottides are derived from the head by a kind
of budding. Thus it is that so long as the head remains the
tapeworm continues to grow.

Digestion.—There is no digestive system, the nutrition
simply being absorbed from the liquids of the host.

The nervous system consists of a pair of ganglia, from which
two main nerve-cords extend back through the length of the
worm.

The excretory or water-vascular system consists usually of

38 BRANCH PLATYHELMINTHES

four principal trunks extending throughout the scolex and
proglottides.

Multiplication and Development——Each proglottis, as it
matures, becomes hermaphroditic. Since these proglottides
are originally developed from the head, the posterior ones are
oldest. When filled with embryos, they are detached and pass
out with the waste material from the intestine. When taken
into the alimentary canal of the hog with its food, the hooked
embryos bore through the intestinal wall and into the voluntary
muscles, where they grow and
continue to develop until they

erty SPR

oS

Fig. 28—Tenia echinococ’/cus, en- Fig. 29.—Portion of the intestine

larged. (Mosler and Peiper.) of « dog infested with echinococcus
tapeworms, natural size. (Oster-
tag.)

reach the bladder-worm stage, or cysticercus. When pork
containing a cysticercus is eaten, unless it has been killed by
thorough cooking, the head is everted from the bladder-like
covering and is attached to the intestinal wall of the host,
where proglottides are rapidly developed. These mature in
ten or twelve weeks.

Species.—There are many species of tapeworms. One form,
Tena saginata, which occurs in man, is obtained through
eating beef cooked rare; another form, Tania soliwn,' already
mentioned, from eating pork; and another, Bothrioceph’alus

1 Tenia solium is sometimes found in the encysted or intermediate stage
in the muscles, eye, or brain of man. The eggs are thought to have been

taken into the stomach with lettuce, cress, and the like, which had been
watered with liquid manure.

NEMERTINEA 39

latus, from eating fish. The latter species is the largest tape-
worm found in man and sometimes reaches a length of 40 feet,
and is composed of more than four thousand proglottides. It
is rare in America, but is abundant in Russia, Switzerland, and
the eastern provinces of Prussia. Another form (Fig. 28),
perhaps the most formidable, is a small one, T@’nia echinococ’cus,
which lives, in the adult stage, in dogs (Fig. 29), and the eggs
are easily taken into the human stomach by a person fondling
and kissing infested dogs. The embryos (Fig. 30), when set

Fig. 30.—Portion of hog’s liver infested with echinococcus bladder-worm.
(Stiles.)

free, work their way into the liver, lungs, brain, or other organs,
and produce tumors which sometimes reach a large size. Several
species are found in domestic birds, one causing epidemics
among chickens. A variety of Te’nia cenu’rus, in the brain of
sheep, causes “staggers.” Rabbits, horses, cats, mice, and
rats are also infested by tapeworms.

CLASS IV. NEMERTINEA

(Doubtful Platyhelminthes)
The Nemertineans are most abundant in the mud or under
stones along the seashore, only a few species living in fresh
water. They differ from all other Platyhelminthes in having

40 BRANCH PLATYHELMINTHES

an alimentary tract with an anal opening and a distinct blood-
vascular system.! They are usually dicecious.?

Geographic Distribution.—This branch of animals is the most
widely distributed of any above the protozoans. They are
found on land, in streams, and in the depths of lake and sea.
The parasitic forms are found in some stage in almost every class
of metazoans, while others have a commensal life with ascidians.
All are carnivorous.

Economic Importance-——Many domestic animals are hosts
for these parasites and much loss is occasioned thereby. A
number of class Cestoda are parasitic in man and cause annoy-
ing if not dangerous diseases. The only sure preventive of these
parasites is to have all meats thoroughly cooked and fruits and
vegetables well washed.

Important Biologic Facts—An anterior end—one placed
foremost in locomotion—and a posterior end appear for the first
time in platyhelminthes. Also right and left and dorsal and
ventral sides are found.

In the Nemertinea there is an alimentary tract with a mouth
and an anal opening. There is no distinct ccelom.

Class Turbellaria is the most primitive and the most closely
related to the Ceelenterates, but it is not thought to be derived
from them, though it shows special points of resemblance to the
Ctenophora. It is thought that Trematoda and Cestoda are
descendants of Turbellaria. In Trematoda is seen an alterna-
tion of generations consisting of the succession of several dis-
tinct generations in regular series. Such an alternation of gen-
erations is termed heterogeny. The simple structure of parasitic
forms illustrates the principle that easy life—one requiring
little exertion—is accompanied by a low stage of development.

Classification.—

Class. Examples.
I. Turbella’ria. Planarians.
II. Trématd’da. Liver-fluke.
III. Céstd’da. Tapeworms.
IV. Nemertin’ea. Carinella, Tetrastemma, etc.

1McMurrich, p. 160; Osborn’s ‘‘ Economic Zodlogy,” p. 85; Kingsley's
Hertwig, p. 289. ‘
2 “Invertebrate Zodlogy,”’ MeMurrich, p. 162; Parker and Haswell, p. 279.

BRANCH NEMATHELMIN’THES

Round- or Thread-worms.—The worms of this branch are
elongated and cylindric and have a ccelom or body cavity.
The vinegar-eel affords a good example. They differ from
annelids in that they are not divided into segments or rings.

CLASS I. NEMATODA

The members of class Nématd’da are best known as para-
sites, but there are many fresh-water and marine forms.

The tough body wall encloses a body cavity which surrounds
a straight alimentary tube having a terminal mouth and a
ventral anal opening. An excretory system is usually present.
The nervous system consists of an esophageal nerve ring which
sends out six nerves anteriorly and six posteriorly. The only
sense organs are sensory papille on the lips. The sexes are
usually separate. Many of the aquatic forms are free. Some
of the parasites infect plants, as Tylen’chus trit/ict, which does
great damage to wheat, and Heterode’ra schach'tit, to turnips in
Europe.

One form, Ascaris nigrovenosa,! living a parasitic life in the lungs of
frogs and toads, is hermaphroditic. The embryos reach the alimentary
canal and pass out with the waste material. In water they develop into
a stage in which the sexes are separate. The eggs develop in the body of
the female and devour the entire substance of the tissue of the mother,
leaving only the cuticle. When set free they live in the mud until they
are taken into the mouth of a frog, when they pass into the lungs and
develop into the hermaphroditic stage. Here, again, is a peculiar alterna-
tion of generations (heterogeny), the alternation of an hermaphroditic with
a dicecious form.

Trichinel’la spira’lis (Fig. 31) is another member of this class. In the
adult stage it lives in the alimentary canal of man or of other mammals.
The length of the adult male is about 7; inch, and that of the female about
4 inch. The sexes are separate. The young, at least one thousand, are
born alive. The young worms (Figs. 32, 33) pass through the intestinal
wall and make their way to the voluntary muscles, where they penetrate
the sarcolemma and become encysted.

1 Parker and Haswell, vol. i., p. 286. McMurrich, p. 176.
41

42 BRANCH NEMATHELMINTHES

Fig. 32.—Larve of Trichinella spiralis in mus-
cle, not yet encysted; enlarged. (Leuckart.)

Fig. 33.—Piece of pork showing larve of
Trichinella spiralis encysted in the muscle-
fibers; natural size. (Ostertag.)

Fig. 31.—Trichinella
spiralis. Adult female,
showing embryos, emb., in
uterus; gp., genital open-
ing through which the
embryos are discharged; Fig. 34.—Encysted larva of Trichinella spira-
enlarged. (Leuckart.) lis; enlarged. (Leuckart.)

NEMATODA 43

When the infested flesh, unless thoroughly cooked, is eaten by man the
cysts are dissolved, the young entering the small intestine, the worms con-
tinue developing and become sexually mature in a few days, the female
penetrates into the superficial layer of the intestinal villi, and in the course
of a month gives birth to young, and then dies. The young wander
through the lymph-vessels and blood-vessels into the capillaries, pass into
the muscle and become encysted (Fig. 34), as did the parents in the former
host; 1 ounce of infested pork, unless thoroughly cooked, may liberate
80,000 worms. If half of these were females, each producing 1000 embryos,
40,000,000 worms would shortly begin to migrate into the muscles, causing
trichinosis, which may be fatal. The worst epidemic known was in kmmers
Leben, Saxony, in 1884, where 364 persons were infected from eating one
pig, and 57 persons died within a month.

The Guinea-worm (Dracun’culus medinen’sis) is an East India parasite
in the subcutaneous connective tissue of man. It is long and slender,
sometimes 1 yard long. It forms abscesses under the skin. When the
newborn young pass out of their host, if they pass into water, they enter
the body of a small crustacean (the Cy-
clops), which is necessary to their develop-
ment. It is supposed that they reach
the human system through the Cyclops,
which is swallowed in unfiltered drinking-
water.

Fig. 35.—Eggs of the gape-worm Fig. 36.—Windpipe of chicken
(Syn’gamus trachea‘lis), one of them split open to show gape-worms at-
hatching; enlarged 260 times. tached to its inner surface; en-
(After Mégnin.) larged. (After Mégnin.)

The hook-worm (Neca/tor america’nus), of the Southern United States
ae the West Indies, is thought to have been introduced from Africa by
slaves.

“In hook-worm disease we have ground-itch, tibial ulcer, anemia, inter-
ference with physical and mental development, and, in bad cases, dirt
eating.” }

Other Species.—There are various other species. Some, as the pin-worm
(Oxyuris vermicularis) and the round-worm (As/caris lumbricoi’des), are
parasitic in man. Some are parasitic in other mammals and some in birds.
One of the latter, Syn’gamus trachea/lis (Fig. 35), about } inch in length,
causes ‘‘ gapes”’ in poultry (Fig. 36).

1 Stitt, 244.

44 BRANCH NEMATHELMINTHES

Gordius, the “ hair-worm,” is found in watering-troughs and erroneously
believed by superstitious people or those ignorant of biologic principles to
be horse hairs transformed into live worms. The larve are parasitic in
the grasshopper, the adults live in water. Agassiz tells of experimenting
with one 18 inches long which was wrapped in and out of its eggs, which
were rolled up into a ball about the size of a coffee bean. He disentangled
it and it ‘‘ sewed ” itself through and through the little white mass. Three
times he separated the worm from its eggs, and each time the process of
entangling was repeated, convincing Agassiz that there was a definite
purpose in its attempts, and that even a being so low in the scale of animal
existence has some dim consciousness of a relation to its offspring.t

He placed a small portion of the egg mass under the microscope, and
estimated that there were not less than 8,000,000 eggs in the whole mass,
which, when unwound, made a string 12 feet long.

CLASS II. ACANTHOCEPHALA

Most of the class Acan’thocéph’ala are small parasites. The
chief genus (Echinorhyn'chus) is parasitic in the intestines of
mammals, birds, reptiles, amphibians, and fishes. The largest
species is found in the pig, and one species, Echinorhynchus
hominis, is extremely rare in man.

CLASS I. CHATOGNATHA

This class contains but two genera of curious arrow-shaped
worms, all but one species of which are pelagic. They are
hermaphroditic and have three pairs of coelomic pouches,
“ fins,”’ and bristle-like jaws.

Economic Importance.—In this branch may be found worms
which are harmful and those which are helpful to man. Those
forms like Trichinella spiralis, which are parasitic in man, are
very injurious. The only preventive upon which it is safe to
rely is thorough cooking.

Those forms which infest wheat and turnips are also harmful
to man, in that they destroy his food; while Gordius, which is
parasitic in the grasshopper, is indirectly beneficial to man.

Important Biologic Facts——For the first time in the scale of
animal life, a celom, or body cavity, appears. It is filled with a
clear fluid, and through it extends the straight alimentary tube
which consists of pharynx or stomodeum, an intestine, and a
rectum. There are no circulatory and no respiratory organs.

1“ Methods of Study in Natural History,” Agassiz, pp. 63, 64.

CH.ETOGNATHA 45

This branch presents similarities to both Platyhelminthes
and Annulata, but the relationship with either is not close.
Classification.—

Class. Examples.
I. Némato’da. Trichina, Gordius.
II. Acan’thocéph/ala.! Echinorhynchus.
III. Chetog’natha.! Sagitta.

1“The affinities of the Acanthocephala and Chetognatha with the
Nematoda are somewhat doubtful,” Parker and Haswell’s ‘‘ Zodlogy,”’ vol.
i, p. 275.

BRANCH TROCHELMIN’THES

Tue animals associated together in this group may have de-
veloped independently from trochosphere-like ancestors, but

Fig. 37.—A_ rotifer,
highly magnified (Hy-
datina senta): A, cilia;
a, anus; b, contractile
vesicle; c, water-ves-
sels; c, ovary; f, gang-
lion. (From Holder’s
“Elements of Zodl-
ogy,” American Book
Co., Publishers.)

since they agree in general character-
istics, they have been regarded by some
as constituting a well-marked phylum.
On account of their size they were
formerly regarded as protozoans, but
they are multicellular and possess well-
defined digestive, excretory, nervous, and
reproductive systems. They have no
circulatory system. Respiration takes
place through the surface of the body.

CLASS I. ROTIFERA

The Rotif’era (Fig. 37), or “wheel
animacules,” are many-celled, micro-
scopic, unsegmented animals, most of
which are worldwide inhabitants of fresh-
water ponds and streams, or even of mud-
puddles and water-troughs. A number
of forms are marine.

The anterior end is a retractile disk
surrounded by cilia, which are locomotive
organs as well as aids to securing food.
The mobile tail is often composed of tele-
scopic rings, rendering it retractile into
the trunk. The posterior ring of the tail
frequently has a pair of pincer-like stylets.
These and the adhesive glands enable
the rotifer to attach itself to objects.

There is accelom. The alimentary tube consists of a ventral
mouth, an esophagus, a chewing apparatus (mastar), a glandular
stomach, and an intestine which ends in a dorsal anal opening.

46

GASTROTRICHA 47

The nervous system consists of a dorsal ganglion with which
are connected one or more eye-spots. There are peculiar tactile
organs which consist of ‘ rod-like structures tipped with deli-
cate sensory hairs.” There are excretory and reproductive
organs.

They are dimorphic (of two forms). The sexes are separate.
The males are rarer, much smaller, and less highly developed
than the female. The female lays thin-shelled summer eggs
of two sizes—the larger developing into females, the smaller into
males—and thick-shelled winter eggs, which in the spring de-
velop into females.

The majority are free swimming, being propelled by the
trochal disk, but the Bdelloida also have a looping movement
like that of the leech.

The rotifers may be dried up in the mud for several months,
and upon being brought into contact with water they revive, or,
some think, their contained eggs bring forth live animals.
When in the dry condition they may be carried long distances on
the feet of birds or by the wind.

CLASS II. DINOPHILEA

These, like the rotifers, are modified trochospheres. They are minute
and worm-like. They have a prostomium or head, a body of five to eight
segments, and a short tail. Both the body and the head are ciliated. The
Dinophilea are marine. In the arrangement of the nephridia in pairs,
corresponding to the imperfect segments, and in the tendency to seg-
mentation, they resemble the Annulata.

CLASS III. GASTROTRICHA

This class resembles the Rotifera, though the relationship is not close.
The class comprises a small number of minute fresh-water forms with
spindle-shaped bodies, flattened ventrally. The dorsal surface bears
several rows of cuticular processes, while the ventral surface has two rows
of cilia.

Classification.—
Class. Examples.
I. Rotif’era. Brachionus.
II. Dindphil’ea. Dinophilus.

III. Gastrot’richa. Ichthydium.

BRANCH MOLLUSCOIDA

In this branch there is usually a body cavity, with the ali-
mentary tube suspended by mesenteries. The mouth and anal
aperture are near together, the dorsal surface being shortened.
Inthe adult there is a tentacle-bearing ridge, or lophophore, about
the mouth, containing a compartment of the body cavity.
The tentacles are used not only in securing food, but in respira-
tion. The nervous system consists of one or two ganglia or of a

nerve ring.!
CLASS I. POLYZOA

Molluscoi’da, which usually’form colonies of zodids by budding, are
Polyzo’a. The character of the colony differs, according to the mode of
budding in the different species and the character of the exoskeleton. It
varies from a bush-like colony to a calcareous or gelatinous sheet. Each
zooid has a crown of ciliated tentacles which can be extended or with-
drawn. They are held together by the common exoskeleton formed by
the ectoderm. There is no vascular system. The digestive tract is bent
like the letter U, the anal opening being near the mouth, within or just
outside of the ring of tentacles. The nervous system consists of a gang-
lion situated between the mouth and the anal opening. Polyzoans are
usually hermaphroditic.

CLASS II. PHORONI’DA

The classification of this group of worm-like forms of the sea is doubtful.

The worm is covered by a leathery cylindric tube into which it may
withdraw. The body is unsegmented and bears a crown of tentacles.
The mouth and anus are close together and are situated at the tentacle
bearing end of the body. The body cavity is divided into three chambers.
There is an alimentary tract and a closed system of blood-vessels contain-
ing red blood-corpuscles. The central nervous system consists of a horse-
shoe-shaped nerve ring at the base of the tentacles. The Phoronis is
hermaphroditic. There is a metamorphosis.

CLASS III. BRACHIOP’/ODA

Brachiopods are marine and were abundant in former geologic times,
being very plentiful as early as the Cambrian Period. There are a few
living species.

They are enclosed in a bivalve shell (Fig. 38), the valves being dorsal
and ventral instead of right and left, as in the mollusks. They are at-
tached to foreign objects by a peduncle or stalk, which passes through the
larger or ventral valve near the hinge. They do not form colonies.

1 Parker and Haswell, p. 313.

48

BRACHIOPODA 49

The shell is only partially filled by the body, and the valves are lined
by the mantle lobes, whose free edges are bristled. The mantle lobes
enclose a large mantle cavity. In the body is a spacious ccelom, which is
extended into the mantle lobes. The ealom contains the digestive tract,
the liver, and the reproductive organs. The latter are chiefly in the
mantle lobes. The digestive tract, which is bent much as in the Polyzoa,
consists of gullet, stomach, and intestine. The mouth is surrounded by the
tentacled lophophore or ‘‘ arms.” The inner surface of the tentacles is
covered with cilia, which set up currents in the water and sweep minute
animals and alge into the mouth for food. The heart, usually present, lies

Fig. 38.—Diagram of a brachiopod: 6, Tentacles around mouth, m; i,
intestine; the shell black, the stalk to the right. (Kingsley’s ‘‘ Compara-
tive Zoélogy,’’ Henry Holt & Co., Publishers.)

dorsal to the stomach, to which it is attached. The nervous system con-
sists of an esophageal ring. Sense organs are usually wanting in the
adult.

Important Biologic Facts.—For the first time, according to
the classification used, a closed system of blood-vessels and
red blood-corpuscles are found.

The digestive tract has been developed into gullet, stomach,
and intestine, and a liver also appears.

The Brachiopoda were formerly supposed to belong to branch
Mollusca. But the valves of the shell are dorsal and ventral,
not right and left, while the tentacled lophophore, the character
of the nephridia, and the modified trochosphere larva all tend
to show relationship with members of branch Molluscoida.

Classification.

Class. Example.
I. Polyzd’a. Bugula avicularia (Bird’s-head
Coralline).
II. Phoroni’da. Phoronis.
III. Brachidp’oda. Magellania.

4

BRANCH ECHINODER’MATA

Plan of Structure —These animals are characterized by their
five-rayed or pentameral plan of structure. While the echino-
derm is radially symmetric, the development shows that it is
derived from the bilateral type. The larve are bilateral. The

Vig. 39.—Solas’ler cndcea (small specimen, natural size), oral view.
(Bulletin, U.S. FL C., 1902.)

central portion is the disk, from which arms or rays project, 2s

seen in the starfish. Close examination will reveal this penta-

merous plan in the sea-urchin and in the sea-cucumber. For,

suppose the rays of the starfish were flexed and their edges

joined, the form of the sea-urchin would appear. Again,
50

GEOGRAPHIC DISTRIBUTION 51

lengthen the sea-urchin in the direction of the mouth to aboral
surface, and you have the form of the sea-cucumber. The
crinoid also reveals this plan, not so clearly defined, but it is to
be seen by the careful observer. The number of rays varies in
the starfish, the author having found them with four, six, or
even as many as twenty-two rays.

Fig. 40.—1 and 2, Amphipholis squamata (adult), aboral and oral views.
3 and 4, Asterias vulgaris (small specimen), aboral and oral views. (Bul-
letin, U.S. F. C., 1902.)

The Skeleton or ‘‘ Test.”—The body wall is composed of a
thick leathery substance. In the mesoderm, under the epi-
thelium, calcareous plates arise, many of which are armed with
spines for protection. They are greatly protected also by their
resemblance to their environment.

Geographic Distribution.—All echinoderms are marine, being
abundant even in the deep sea. They are found in all parts of
the globe, but are most abundant in the tropics. At the breed-
ing season most of the free species frequent the shallow waters

52 BRANCH ECHINODERMATA

near the coast, where the ova are fertilized in the water. Echino-
derms of the same species are often gregarious.

The water-vascular system is a marked characteristic of
echinoderms (Fig. 41). It begins externally with the cal-

vO. : at
reproductive glands.- cardiac stomach

wet -.antestinal caecum
anus

pyloric caecum

eve Spotl Pes

‘muscles of the pyloric cacca
Fig. 41.—Dissection of a starfish (Asterias sp.). (From WKellogg.)
careous perforated madreporic plate which is connected by a

calearcous (Stone) canal with the central ring around the
mouth, from which tubes proceed along each arm, in the star-

METAMORPHOSIS 53

fish. On the inside of the floor of each ray are the ampulla,
small bulb-like water-sacs, which are connected with the tube-
feet on the outside of the ray. ‘ By a contraction of the deli-
cate muscles in the walls of the ampulle the fluid in the cavity
is compressed, thereby forcing the tube-feet out. By the con-
traction of muscles in the tube-feet they are again shortened,
while the small disk-like terminal sucker clings to some firm
object. In this way the animal pulls itself along by successive
steps.”’ By the aid of these ambulacral or tube-feet the starfish
is able to turn over if placed upon its back. They also act as
suckers to fasten the starfish to the rocks. When once this is
accomplished, arm after arm may be broken off before the
animal can be pulled loose or the feet will relax their hold.

So-called blood canals accompany the ring and radial canals,
and associated with them are sometimes two intestinal blood-
vessels!

Nervous System.—“ There is a nerve ring and radial nerve,
frequently in the ectoderm, to which may be added an entero-
ceelic or apical nervous system, possibly of peritoneal origin.”

The circulating fluid is somewhat lymph-like and the circula-
tion slow.

“ Respiratory organs are represented by the branchia, or thin-
walled outpushings of the ccelom, either around the mouth, as in
the Echinoi’dea, or on the aboral surface, as in the Asteroi’dea,
the burse of the Ophiuroi’dea, the branchial trees of the Holothu-
roi’dea, and the various parts of the ambulacral system.’’?

The alimentary tube is complete, that is, shut off from the
body cavity and runs through the body. Its length depends upon
the food of the echinoderm. In carnivorous forms, as the star-
fish, it is short, but in vegetable feeders, as the sea-urchins
and sea-cucumbers, the alimentary tube is two or three times
the length of the body.

Multiplication is sexual, as a rule, the sexes being separate
except in rare cases. Fertilization takes place in the water.
They never form colonies by budding.

The metamorphosis, or change from the larval to the adult
form, is as marked as that from the caterpillar to the butterfly.

1 Hertwig’s “‘ Manual of Zodélogy,” Kingsley, p. 331.
2 Thid.

54 BRANCH ECHINODERMATA

The larva is bilateral,! while the adult is radial, the development
being complex.

Generally the young shift for themselves, but cases are
recorded of broods being cared for by the female echinoderm
in a pouch on the dorsal surface.

CLASS I. ASTEROIDEA

To this class belong the starfishes, with their central disks
and varying number of rays, five being the typical number.
They live along rocky seacoasts. Fresh water kills them.
The common starfish (Aste’rias vulga’ris) is abundant along the
Atlantic coast, especially in the vicinity of oyster-beds, to
which they do much injury by devouring the oysters. Star-
fishes are found also on the Pacific coast from Sitka to southern
California. They are said to devour small fishes as well as
crabs.

The body wall is composed of a thick leathery substance zn
which is embedded a great number of calcareous ossicies
(12,000 by estimation), many of which are armed with spines
for protection. Between the spines on the aboral surface are
soft stalked projections ending in pinchers, called pedicella’rie,
with which it cleanses the surface of the body and protects
itself from parasites.

The alimentary tube extends from the oral to the aboral
surface. It consists of a mouth, a short esophagus, and a large
sac-like stomach, which is five lobed and fills most of the disk.
(See Fig. 41, p. 52.) The stomach is eversible and is furnished
with muscles for withdrawing it. From the pyloric, or upper,
division of the stomach the ceca extend, a pair into each arm.
These cxca secrete much fluid, which is emptied into the
pyloric portion of the stomach and used in digesting the food.
From the stomach a short conical intestine extends upward
to the aboral surface. The aboral opening from the intestine is
not exactly in the center of the disk and is often difficult to find.
In a few forms it is wholly obliterated.

Locomotion.—The arms are somewhat. flexible, and, aided by
their tube-feet,? enable the starfishes to move slowly along in

1 Hertwig’s ‘Manual of Zodlogy,’”’ Kingsley, p. 331.
2 See text, Water-vascular System of Echinoderms, p. 52.

ASTEROIDRA 55

search of food. The starfish, by clinging with its sucking disks,
ean travel along horizontal or vertical walls It can bend its
arms or even its central disk, when necessary, to pass through
openings or crevices between rocks. As it moves so slowly, its
direct dispersal is very limited, but since it is not attached, it is
indirectly distributed by the tides and currents. The exceed-
ingly minute young are often borne great distances in this way.

Foods and Feeding.—The starfish is carnivorous and very
voracious; indeed, it seems to eat continuously. It feeds upon
barnacles, clams, oysters (Fig. 42), and, it is said, even small
fishes, or, failing of these, it will eat the garbage thrown along the
shore, thus acting as a sort of scavenger. The worst damage it

oad

Fig. 42._Starfish attacking oysters. (From Fifth Report of Connecticut
Bureau of Labor Statistics.)

does by its gluttony is to the oyster-beds. Oysters and clams
close their shells to the starfish, but it keeps up a steady pull un-
til it gets them open, when it reaches its arms about its prey and
extrudes the lower part of its stomach, envelops the soft parts,
pours out the digestive fluids about them and absorbs them,
then withdraws its stomach, leaving the indigestible parts of its
victim outside the body. Further digestion of the absorbed food
takes place in the pyloric portion of the stomach, aided by the
secretions of the hepatic ceca. The fact that all indigestible
parts are “rejected” may account for the shortness of the in-
testine, and certainly does account for the small or lacking anal
aperture, since there is little left to be “ ejected.”

56 BRANCH ECHINODERMATA

The nervous system consists of a circumoral nerve ring,
from which a nerve proceeds along the ambulacral groove of
each arm to its tip, where it ends in a so-called “ eye-spot ”
which has been proved sensitive to light.

Special Senses.—Besides the general sense of touch and the
“eye-spots,” already mentioned, there is at the distal end of
each ray a tentacle-like organ which is supposed to be the organ
of smell.

Multiplication is sexual. Fertilization takes place in the
water. The starfish may reproduce asexually, for if a ray be
broken off,! either accidentally or purposely by the animal
itself, it has the power of reproducing a new disk as well as the
rest of the arms, with their internal organs. Similarly, if all
the arms are torn off, the disk has the power of growing out new
ones. The young are bilaterally symmetric, free-swimming
animals. The metamorphosis is complicated, resulting finally
in the radial plan of structure of the adult.

The starfish, Linckia linckia, is a host for a parasitic gastero-
pod (Thyca). Some starfishes are gregarious.

In size they vary from less than 1 inch to 3 feet in diameter.
In color they may be yellow, brown, red, or purple.

Geologic Distribution.—The starfishes appeared before the
close of the Cambrian Period, and have been represented in
every age up to the present.

CLASS II. OPHIUROIDEA

These echinoderms resemble the starfish. The arms are
slender, jointed, muscular, and are used for locomotion (Fig.
43). The arms may be much branched, as in the basket-fish,
and are not hollow as they are in the starfish. The ambulacral
groove is closed, the tube-feet are on the sides of the arms,
and have no suckers at their distal ends.

The arms are much more slender and more flexible than those
of the starfish, and locomotion, which is faster than that of the
starfish, is accomplished hy the lateral movements of the arms,
Some species have the power of throwing off picees of their
arms when disturbed.

The digestive organs are confined to the disk, the hepatic

1 Parker and Haswell, p. 400.

UPHIUROIDEA 57

cxca are absent, and the anal opening is lacking. The madre-
poric plate is on the oral side.

Food.—They are carnivorous, feeding upon worms, crabs, and
shell-fish. They are also scavengers.

Multiplication Some lay their eggs in the water, where they
are fertilized and develop into a pluteus stage like that of the

Fig. 43.—Gorgonoceph’alus agassiz’ti (one-fourth natural size). Oral view.
(Clark, in Bulletin 550, U. 8. F. C., 1902.)

Echinoidea, while others are viviparous and care for their
broods. In many species there is also a kind of asexual repro-
duction, the animal dividing through the disk and each half
regenerating its “ other half.”

There are several hundred species known. These echino-
derms are variously called brittle-stars, serpent-stars, and sand-

58 BRANCH ECHINODERMATA

stars. The one most common on our shores (Ophiopholis) is
of a “ general red hue spotted with brown and paler red.”

CLASS III. ECHINOIDEA
The globular or disk-like sea-urchins have the pentameral
plan, as a cleaned “ test ”’ or shell (Fig. 44) will show.
The body wall is composed of several hundred pentagonal
calcareous plates arranged in regular order in twenty rows,
the whole forming a sort of thin case or shell (see Fig. 44).

Fig. 44.—Sea-urchin (chi/nus microsoma) with spines nearly all removed
from ‘ test.” (Chapin and Rettger.)

The ossicles, or plates, are armed with very long sharp spines
for defense (Fig. 45). Alternate rows of plates are perforated
for the passage of the tube-feet, there heing no grooves. These
ten rows of perforated plates constitute the ambulacral areas,
and the ten rows of unperforated plates constitute the inter-
amlulacral areas.

Color.—The colors are brown, olive, purple, red, green, or blue.

The protective resemblance is good.

The ambulacral system of the sea-urchin is similar in plan

ECHINOIDEA 59

to that of the starfish. Locomotion is very slow and is per-
formed by the tube-feet, aided by the long spines.

The pedicellarie are similar to those of the starfish, but are
more fully developed, having three pinchers instead of two.

The food consists largely of green alge and brown seaweed,
for the sea-urchin is a vegetable feeder, though it eats small
marine animals also.

Digestive System.—There are five hard white teeth with
which they gnaw their food. These teeth are connected with a

ory | Uh

Fig. 45.—Strongylocentrotus drobachiensis. Oral_view, showing spines,
“ feet,” and teeth. (Clark, in Bulletin 550, U. 8. F. C., 1902.)

complicated calcareous framework under muscular control.
The whole apparatus is called “ Aristotle’s lantern.”

The intestines are long, coiling about two and a half to three
times, instead of being short like those of the carnivorous star-
fish.

The hepatic ceca and gastric pouches are absent. This
lack, as well as the structure of the mouth parts and the long
coiled intestine, correlates with the feeding habits of these
herbivorous animals,

60 BRANCH ECHINODERMATA

The nervous system is upon the same plan as that of the
starfish.

Multiplication.—The eggs are laid in the water and fertilized
by the tadpole-like sperm cells. Some forms have a marsu-
pium, or brood-pouch, in which the eggs are hatched.

Development.—After fertilization, segmentation of the egg
takes place until the bilaterally symmetric young “ pluteus,’”’
which is very unlike the adult, appears. It is free swimming
and lives on minute organisms it can procure in the water. As
it develops it takes on the radiate or pentameral plan of its
branch. The “sand dollars’ so common on both the Pacific
and the Atlantic coasts are flat sea-urchins with short spines.

Geologic Distribution—A primitive type of sea-urchin ap-
peared in the Ordovician period.!

CLASS IV. HOLOTHUROIDEA

Holothurians are free, and a close examination reveals the
pentameral plan of the branch, although they are more or less
bilaterally symmetric.

Fig. 46.—Cucwma’ria frondo’sa, side view. Note tentacies and rows of
feet. (Clark, in Bulletin 550, U.S. F. C., 1902.)

The shape (Fig. 46) is much like that of the garden eueumber
in our common varictics, but some are long and slender and
1 Scott's “Ceology,” p. 381.

HOLOTHUROIDEA O61

more worm-like in appearance. Some are so long and slender
that they are sometimes thought to be worms.

The size varies from } inch in one species found upon the
Massachusetts coast, to 3 feet, in another species found in
Monterey Bay, California.

The body wall is tough, leathery, muscular, and not so rigid
as in the starfish or sea-urchin, although minute calcarcous
spicules are scattered throughout it.

The tube-feet may be in rows, or scattered, or entirely want-
ing, depending upon the species, of which several hundred are
recorded. The sea-cucumbers
move with their long axis parallel
to the ground. They creep along
with the help of the tentacles.

Protective Resemblance.—
Their colors, which are reddish
brown or yellowish, harmonize
so closely with those of their en-
vironment that their protective
resemblance is almost perfect.
As the animals rest on the bot-
tom of the sea with their feathery
tentacles spread out they closely
resemble the vegetation of the
sea bottom. A person may
stand within a foot of the sea-
cucumber and not see it.

The alimentary tube (Fig. 47) ;
is several times the length of PO cc Pea er ee a
the animal, and the intestine is mentary tube, al.t. (Leuckart.)
coiled in a uniform manner.

The food of the holothurians consists of organic matter
obtained from the sand which they swallow, or of small animals
which they capture with their tentacles. They are nocturnal
in their feeding habits, resting quietly during the day on the
bottom of the sea or buried in the sand.

The respiratory system consists, probably, of the so-called
“respiratory trees,” two hollow, much-branched organs open-
ing into the cloaca, which is periodically filled with water.

62 BRANCH ECHINODERMATA

They are probably excretory organs also, and are connected
with the manipulations of the tentacles.!

Multiplication is gencrally similar to that of the starfish,
except in rare cases of hermaphroditism. There arc also cases
recorded of the female caring for her brood in dorsal pouches.
In unfavorable conditions they void the whole viscera and yet
live and replace the lost parts.”

In the development from the bilateral larva to the radial
adult there is a marked metamorphosis.

Several species are hosts for certain parasites. A small
fish infests the cloaca and branchial trees of one or two species.
A snail lives in one species and a mussel in another.

Use.—They are used for food hy the Malays, who call them
“¢repang,”’ and use them principally for soups. Millions of
them are captured in the south seas, where hundreds of vessels
are engaged in the trepang fisheries.

Distribution—Holothurians are widely distributed, being
found from the arctic te the tropical regions.

Geologically, they date from the Carboniferous Period.

CLASS V. CRINOI’/DEA

Crinoids are fixed echinoderms with a flexible stem or stalk
of caleareous perforated disks, bearing a flower-like body at
the top of the stem (Fig. 48). This body consists of a cup-
shaped center bearing five or ten arms, usually branched.
The “ feather stars,’ found at a less depth, later become de-
tached and float around in the water.

Ambulacral Grooves.—Five ciliated ambulacral grooves
(Fig. 49) extend from the mouth out on the arms and their
branches, and give off branches to the pinnules. They serve
as channels through which the food passes to the mouth, and also
for the purpose of respiration.

Food.—They feed on smail crab-like animals and on marine
unicellular animals and plants.

The nervous system consists of a nerve ring surrounding the
mouth, and given off from this nerve ring are a series of ambu-
lacral nerves which extend the entire length of the arms and
pinnules.

1 Parker and Haswell’s “ Zoology,” vol. i, p. 372. 2 Tbid., p. 400.

CRINOIDBA 63

(Brehm.)

_ Fig. 49—Mouth area of a crinoid (Comat’ula), showing the course of the
intestine leading from the mouth (m) to the vent (a); g, grooves leading

from arms to mouth. (From Kingsley’s ‘ Comparative Zodél uP :
Holt and Co., Publishers.) , oes

Digestive System.—The mouth is directed upward and leads
into the digestive tract, consisting of esophagus, stomach, and

64 BRANCH ECHINODERMATA

intestines. The interradial anal opening (see Fig. 49) is
situated near the mouth.

Multiplication —Crinoids multiply by eggs, which pass
through complex changes before reaching the adult stage.

Habitat—The living crinoids are deep sea animals with
the exception of two genera, which live at a less depth. Some
have becn dredged from a depth of 11,100 feet. At this depth
the water pressure must be enormous.

Geologic Distribution—Primitive types (the cystids and
blastoids) of this group are among the most ancient fossils.
True crinoids appeared before the close of the Cambrian
Period. They reached their culmination in the Carboniferous
Period. The crinoid fossils of this period are so numerous that
many beds of limestone are composed principally of them.
Burlington, Iowa, and Crawfordsville, Indiana, are noted for
their numerous and well-preserved fossil crinoids. Crinoids,
though formerly of such vast numbers, are now almost extinct.

Important Biologic Facts—Echinoderms are radially sym-
metric, but embryology shows that they have developed from
the bilateral type. It is reasonable to regard those classes of
echinoderms as the more ancient which have the radial sym-
metry less completely developed.!

The locomotor-ambulacral system is found in no other
branch.

The echinoderms are a singularly isolated group, and we
look in vain among the known members, living and fossils, of
other branches for any really close allies.

Classification.—
Class. Examples.
I. Asteroi’dea. Starfishes.
II. Ophiuroi’dea. “ Brittle-stars.”’
Ill. Echinoi’dea. Sca-urchins.
IV. Holothuroi’dea. Sea-cucumbers.
V. Crinoi’dea. Sea Lilies, ‘ Feather-stars.”’
VI. Cystoi’dea. Fossil.
VII. Blastoi’dea. Paleozoic fossil, asin Class VI.

1 Parker and Haswell’s “ Zodlogy,”’ vol. i, p. 401.

BRANCH ANNULATA

Tue branch Anniila’ta is distinguished from the other branches
of worms by having external and internal segmentation, that is,
being divided into rings or segments (metameres) ‘“ containing
homologous organs or similar portions of a continuous organ.’

They have, usually, a well-developed ccelom or body cavity,
divided into segments by muscular partitions or septa.

These worms are bilaterally symmetric. The body is usually
elongated.

CLASS I. CHATOPODA

Class Cheet6p’dda consists of fresh-water and marine annelids
which bear sete, or bristles. The set arise from special fol-
licles, and may occur singly or in bunches. These setze, which
are controlled by special muscles, act as tiny levers in locomo-
tion.

They have a body cavity which is partially divided into com-
partments corresponding to the segments. The alimentary
tube extends through the body and is usually constricted at the
septa. There is usually a well-developed circulatory system.
Respiration is usually through gills or branchiz and through
the body wall. In some forms the sexes are distinct, while
other forms are hermaphroditic. Fresh-water annelids de-
velop without a metamorphosis, but in many marine forms the
trochosphere larve occur.

Few are true parasites, but a number are commensal, habitu-
ally associating with other animals for their food and shelter.
Many sea-worms are phosphorescent.

The earthworm (Lum’bricus) has an elongated cylindric body
of many segments or metameres.

Digestive System (Fig. 50)—The mouth is covered by a
rounded, lobe-like projection, the prostomium. The mouth
leads into a small buccal cavity, back of which is the larger.
thick-walled, muscular pharynx. This pharynx can be pro-

1 Galloway’s “ Zodlogy.”
5 65

66 BRANCH ANNULATA

truded and retracted.

Fig. 50.—Darthworm
dissected to show aliment-
ary tube, al. t. (From
Jordan and Kellogg,
“ Animal Life,” D. Apple-
ton and Co., Publishers.)

The radially arranged muscular fibers
which run from the pharynx to the
body wall retract the pharynx and at
the same time dilate it. Back of the
pharynx is the narrow esophagus, with
a pair of pouches and two pairs of
calciferous glands, which communicate
with these pouches and which contain
alimy fluid. Posterior to the pharynx
is the thin-walled crop, and back of
this is the very thick-walled rounded
gizzard, with its tough, chitinous lin-
ing, in which the food is ground by
sand, and from which the intestine ex-
tends to the anal opening in the pos-
terior segment.

The typhlosole, a prominent ridge
extending along the middle of the dor-
sal surface of the intestine and dipping
down into the interior, renders the
hollow of the intestine crescent shaped.
This typhlosole increases the absorb-
ing surface and is well supplied with
blood-vessels.

The circulation is carrried on in a
well-developed system of blood-vessels.
The dorsal tube extends along the
median line of the dorsal surface and
is plainly seen in the live earthworm.
The forward movement of the blood can
usually beseen. The ventral blood-ves-
sel lies below the alimentary tube. In
this ventral blood-vessel the blood is pro-
pelled backward by the peristaltic action
of the tube. The three smaller blood-
tubes, the subnural and two lateral
nural tubes, lie close to the nerve cord.

Hach segment has a transverse vessel connecting the dorsal
and ventral blood-vessels. Those from the sixth to the eleventh

CHTOPODA 67

segment are dilated and pulsate ryhthmically, hence are some-
times called hearts. The blood is red, the color being due to
the presence of hemoglobin (the same substance which makes
our blood red) in the liquid itself, though the blood contains
colorless corpuscles.

The nervous system consists of a double cerebral ganglion
connected with a double ventral chain of ganglia by a pair of
commissures which pass around the esophagus.

The earthworm has no eyes, yet it can distinguish not only
light, but the direction from which it comes, and it will crawl
“ away from the light of high intensity and toward a light of low
intensity.”” This tendency, and the fact that the moisture of
the skin would be rapidly evaporated in daytime, and the ab-
sence of enemies, induce the earthworms to feed at night.

The earthworm has no organs of hearing, but its general sense
of touch is so delicate that it detects the approach of danger
by the jarring of the earth about its burrow.

It can distinguish and choose between different kinds of food,
so it must have a sense akin to smell or taste. It is thought that
the ‘ goblet-shaped bodies”? on the prostomium and on the
anterior segments are the seat of this sense.

The body wall is composed of, first (on the outside), the cuticle,
then the epidermis, the dermis, a muscular layer of circular
fibers, a layer of longitudinal muscle-fibers, and underneath this
the ccelomic epithelium which lines the body cavity.

Respiration takes place through the thin moist skin which
is everywhere underlaid by a network of blood-vessels. These
absorb the oxygen from the air and give off the carbonic acid
gas through the skin.

Locomotion.—Each segment, except the one at each end of the
worm, is furnished with four pairs of sete, or short, stiff, chitin-
ous bristles. They arise from the setigerous glands or sacs
made by the infolding of the cuticle. By special muscles, at-
tached to the base of each of these sacs, the sete can be turned
in different directions. In locomotion the earthworm uses
these setze as levers. When it moves forward the sete are
turned backward and stuck into the soil, the longitudinal
muscles contract, pulling the body together, then the circular
muscles contract, making the body smaller and longer and forc-

68 BRANCH ANNULATA

ing it forward, since the sete prevent its moving backward.
When the earthworm moves backward the sete are directed
forward, and the same processes propel the worm backward.

Excretion.—In all the segments of the body except the first
three and the posterior one is a pair of tubular kidneys (nephri-
dia). Each begins in a ciliated funnel—which opens into and
takes up the waste from the body cavity—in the back part of a
segment, and continues in a long, much-looped tube, which
opens externally by a small excretory pore on the ventral
surface of the segment posterior to the one in which the funnel-
shaped beginning is situated.

Multiplication—The earthworm is hermaphroditic, but
cross-fertilization takes place. The lateral and dorsal portions
of the segments from the thirty-second to the thirty-seventh
are swollen and somewhat fused together, forming a sort of
girdle (the clitellum). The glands of this clitellum secrete a
viscid fluid. This secretion hardens, upon exposure to the air,
and forms a band or collar about the clitellum. This collar
moves forward, gathers the eggs and sperms! as it passes the
openings, and finally is slipped off over the head.? The ends of
the collar now close and it forms a tough egg-capsule. The
egg-capsules are hidden under stones, boards, or logs, or are
buried in the earth, especially about barnyards and compost
heaps. ‘‘ The worms are about 1 inch long when hatched.’

They hibernate below the frost line in winter.

Enemies.—The chief enemies are moles and birds. To
avoid the birds they feed at night or early morning, and some-
times drag a pebble into the mouth of the burrow, closing it
after them.

The marine worms (Polyche’ta) are dicecious, and the young undergo a
more or less complete metamorphosis. The larva is a trochosphere.1 Some
burrow in the sand; some are free swimming; some secrete a mucus which
hardens and forms tubes; others form tubes by sticking together with
mucus pieces of shell, sand, mud, or limestone. Most of the tube-building
species are fixed to some object, but a few carry their tubes about. Many
of these marine worms live in shallow water, but some have been found
at a depth of 3000 fathoms.

1 These have been obtained from another earthworm.
2 Shipley and MacBride, p. 100.

3 Colton, ‘ Descriptive Zodlogy.”

4 See Glossary

HIRUDINEA 69

The nereis, or sand-worm, which is found on the seashore, has a distinct
head, bearing eyes and tactile sense organs, such as tentacles and palpi.
Each segment has a fleshy outgrowth, the parapodium, bearing many bristles.
“This is the first appearance of true appendages, though they are not
jointed to the body nor in themselves.”’

The sand-worm varies in color in different stages, and the length varies
from 6 inches to 2 feet.

It has an eversible pharynx, which, when infolded, conceals two horny
jaws. These jaws are deeply notched and the ends are incurved. When
food is taken the pharynx is everted, the jaws thrust forth, and the prey
seized and swallowed.

CLASS II. GEPHYR’EA

Class Géphyr’ea is composed of oval or spindle-shaped worms,
which are unsegmented in the adult form. Sete are entirely
wanting. The mouth, which is at the anterior end, is either
surrounded by tentacles or overhung by a “‘ proboscis ”’ which
may be several times the length of the body.

These worms are widely distributed. They live in both
deep and shallow water and, ‘for the most part, either in
natural rock-fissures or in burrows which they excavate in sand
or mud or in coral or rock.”

CLASS III. HIRUDIN’EA

The body of the leech tapers at both ends and is flattened
dorsoventrally. It is composed of many segments which are
superficially divided into several rings, so that there are not so
many true segments as there are surface rings.

The principal order of this class contains the common fresh-
water leech familiar to barefoot boys. It is a temporary para-
site on vertebrates.

The leech (Fig. 51) has no setee nor appendages, but is pro-
vided with two suckers. The one on the posterior ventral sur-
face is used for attachment in locomotion, and the other, which
surrounds the mouth and is not well developed, is used in suck-
ing the blood into the large crop. In the pouches of this crop,
it is said, enough blood can be stored to last a year. A narrow
stomach and a short intestine follow the pouched crop. The
ccelom is considerably obliterated by a growth of muscle and
connective tissue, called parenchyma.

Leeches are hermaphroditic. The eggs are usually laid
in small packets or cocoons, and these are deposited in moist

70 BRANCH ANNULATA

soil. The eggs are hatched in four or five weeks, but it takes
them several years to mature. Some leeches are said to live
twenty years.

Leeches are widely distributed. Many of them are in-
habitants of fresh water. Some live in salt water, while others
live in the forests of many regions, especially those of the
tropics, where they are the terror of men
and beasts.

One species ( Hiru’do sanguisu’ga) is a parasite
in the nasal passages of man. Another (Hamop’-
sis vo’rax) lives in the pharynx or trachea of the
horse, being taken in with water when small.

Another form (Branchel’lion) is a permanent ex-
ternal parasite on fishes.

Distribution.—The members of branch
Annulata are widely distributed, the rep-
resentatives of its many species being
found from frigid to tropical regions, and
even in the isolated islands of the sea.

It is known that marine worms existed
in the Cambrian Period by their “‘ tracks
and borings in the sand, which are now
consolidated into hard rocks.”

Economic Importance.—The earth-
worm swallows the soil which it exca-
vates for the sake of the partially de-
cayed organic matter it contains, which
the worm appropriates to the building
up of its body tissue. The indigestible
portions it deposits on the surface at

ite Ki Raa a night as coiled castings. They also feed
2 ese “i, Amteton Ol fresh or decayed leaves which they
sucker; b, posterior drag into their burrows, and sometimes
pein nus etl upon young seedlings and tender roots.
i, intestine; s, es eee Darwin, who studied the earthworm for
of the skin. (Holder.) forty years, estimated that in the tillable

soil of England there were fifty thousand
earthworms to the acre, and that they brought to the surface
from 10 to 18 tons of soil annually. In this way the whole

HIRUDINEA 71

superficial layer would be enriched by passing through their
bodies in a few years. Their burrows may extend vertically or
obliquely for several feet underground, their depth depending
upon the distance of the moist soil from the surface. ‘‘ They are
connected by underground tunnels, so that the soil is thoroughly
exposed to the chemical action of the gases and acids of the air
and water.’’! Thus the action of the earthworm has both a
chemical and a mechanical effect upon the soil.

Leeches were formerly used very frequently by doctors when
bleeding was more often practised. They are still sometimes
thus used. They are raised in France for commercial purposes.
Swamps are stocked with them and they are fed upon old and
worn out farm animals.

Important Biologic Facts.—This branch is distinguished from
all preceding groups by its metameric segmentation. The
excretory system is characterized by the peculiar nephridia.
There is a well-developed circulatory system and a circulating
fluid containing hemoglobin. In leeches eyes are found, while
the ‘ goblet-shaped organs’? in leeches and earthworms are
thought to be the seat of smell or taste. True appendages ap-
pear in the Nereis.

The trochosphere larve show relationship between Chetopoda
and the Turbellaria and the Nemertinia.

Classification.—
Class. Examples.
I. Cheetdp’oda. Earthworms, Sand-worms.
II. Géphyr’ea. Sipunculus.
III. Hirudin’ea. Leeches.

1 Jackson and Daugherty, ‘Agriculture Through the Laboratory and
School Garden.”

BRANCH MOLLUS’CA

THESE animals have soft, unsegmented bodies, as contrasted
with the segmented Arthropoda. The body is generally bi-
laterally symmetric, but it may be asymmetric, as in the snail.
They vary in size from a fraction of an inch to from 2 to 5 feet
in length; and in weight from a fraction of an ounce to 500
pounds. The body may be naked, as the slug; or covered

{een ai = sie TCT

with a univalve shell, as the snail; or with a bivalve shell,
as in the common mussel; or it may have an internal horny
pen, as in the squid. The structure and form of the Mollusca
are very various, and the number of known living and fossil
species exceeds forty thousand. Some mollusks are marine,
some are fresh-water forms, and others are terrestrial.

fe

PELECYPODA 73

The circulatory system consists of a dorsal heart of one
ventricle and one or more auricles, enclosed in a pericardium.
Aorte carry the blood from the ventricle to different parts of the
body, but the blood-vascular system is not entirely closed.

Respiration is carried on through the body wall in a few
Mollusca, but most of them breathe through gills or lungs.

The nervous system is characterized by three pairs of ganglia
which are joined by connective nerve cords. The cerebral
ganglia are situated dorsal to the esophagus and supply the
tentacles and eyes. The pedal ganglia lie ventral to the mouth
and supply the foot and otocysts. The visceral ganglia, also
ventral, but farther back, supply the body, the mantle, and the
so-called “ osphradia,” or olfactory organs. Some mollusks
lack special sense organs.

Locomotion is accomplished by the single so-called “ foot,”
a muscular plowshare-shaped thickening of the body.

Multiplication—The Mollusca may be sexually separate or
hermaphroditic.

This branch includes some very valuable food animals for man,
as clams and oysters. Other examples are snails, slugs, scallops,
cuttle-fishes, squids, and fresh-water mussels.

CLASS I. PELECYPODA

This class is called by various names by different zodlogists,
depending upon the character taken for the basis of classifica-
tion—as Aglossa (without a tongue), Acephala (without a
head), Bivalva (of two valves), Pélécyp’oda (hatchet-footed),
Lamellibranchiata (leaf-like gilled). We may then characterize
this class as the hatchet-footed, headless, tongueless, bivalved,
leaf-like gilled mollusks. Mussels, clams, and oysters are com-
mon examples of this class.

The body is soft, unsegmented, and is modified into the large
“foot ” used for locomotion. The mantle, a great fold of skin,
covers the body, one lobe over each side. Between the mantle
lobes and the body are the four large leaf-like gills. The labial
palpi are the small leaf-like structures anterior to the gills, and
lead into the mouth.

Food consists of small organisms which the water carries
into the mantle cavity and to the ciliated labial palpi, which

74 BRANCH MOLLUSCA

pass the food into the mouth. From thence the food: passes
into the stomach and to the long coiled intestine which passes
through the pericardium, usually perforates the ventricle, and
ends dorsal to the posterior adductor muscle.

The Pelecypoda are scxual and sometimes hermaphroditic.
There is a metamorphosis, there being usually a trochosphere
stage.

The sea mussel (My/tilus) is an cxample of this class. Great clusters
of this edible mussel are found just below low-tide marks. The shell is
generally of a purple or dark color. The long slender foot (Fig. 53) throws
out yellowish horny fibers (the byssus), by which the mussel attaches

Fig. 53.—Mytilus edulis: O, Mouth; S, labial palps; P, foot; B, byssus
secretion; Br, gills; AZ, thickened edge of mantle. (After Claus.)

itself to foreign objects. If food becomes scarce or conditions unfavorable,
it can detach itself and slowly move to another position by stretching out
the threads of the byssus and attaching them ahead or above, and then
drawing itself up to them, hence it is sometimes called the ‘* climbing
musscl.

Ano’mia, of the same order as My’tilus, is permanently fixed.

The oyster (Os’trea) is amember of this class, which in adult life is fixed
to the sea bottom or to some foreign object—very often the shell of another
oyster. Great clumps (sce Fig. 52, p. 72) may be thus fastened together,
but their union is not organic. Oysters vary in size from a few inches to
2 or 3 feet, the largest being a Japanese species.

The shell of the oyster (Fig. 54) is rougher than that of the clam, and the
hinge is at the pointed end, which corresponds to the anterior end of the
clam. Its two valves are not alike, but the lower or left one is much
larger and becomes deep enough to contain the body, while the upper or
right valve is flat and serves as a lid. There is but one adductor muscle.

PELECYPODA 75

By its contraction the shell is closed. Its location is changed from year to
year as the animal grows. A brown scar in the shell indicates where the
attachment has been. The oyster can open its shell but little.

The oyster, since it is fixed, needs no organ of locomotion, and so has no
foot. Neither has it any siphon, but the food-bearing water (Fig. 55)
enters along the curved border of the shell and passes out near the larger

Fig. 54.—Shell of typical American oyster: 1, Inner face; 2, outer face.
(Report U.S. Geol. Survey.)

end on the straight side. A fresh supply of sea-water is necessary to fur-
nish it with food and oxygen. If the oysters settle too deep in the mud
or if they are covered by silt and sand in time of storms they smother.
Our species of oysters (Ostrea virginiana) is bisexual, while the European
species are hermaphroditic.1 The reproductive organ is attached to the

1“ Hertwig’s Manual of Zodlogy,”’ Kinglsey, p. 367.

76 BRANCH MOLLUSCA

large adductor muscle. The eggs are deposited in the water. They
are very numerous. It has been estimated that one female will produce
from 9,000,000 to 40,000,000 eggs in a single season. The breeding scason
is from May to August. If the eggs are not eaten by enemics or carried
away by currents, they sink to the bottom. After a few hours of develop-
ment the larve swim to the surface. Multitudes of these larva are de-
voured by surface-living fishes. The larve (Fig. 56) swim by means of
cilia. Ina few days the larve or fry, as they are called, sink to the bottom

Fig. 55.—Food of South Carolina oyster. A few typical organisms
(x 225). Numbers 1 to 20 are diatoms. 1-5, Navicula (Bory); 6, N.
didyma (K.); 7, Pinnularia radiosa (?) (IX. 8.); 8, Amphora sp. (X.);
9, Pleurosigma fasciola (E.8.); 10, P. littorale (8.); 11, P. strigosum (%.);
12, Actinocyelus undulatus (KK.); 13, Coscinodiscus radiatus (E.); 14,
Cyclotella rotula (E.); 15, Synedra sp. (E.); 16, Diatoma sp. (De C.);
17, Cymbella sp. (Ag.); 18, Mastogloia smithii (Thw.); 19, Triceratium
alternans (Br. Bai.); 20, Biddulphia sp. (Gr.); 21, Grain of pine pollen
(Pinus rigida); 22, Foraminifera (Rotalia); 23, Zodspore (Ulva?); 24,
Spicules. (After Bashford Dean.) (From Moore, U. 8. Com. of Fish
and Fisheries.)

and attach themselves by the mantle-fold to some other oyster or to any
object with which they come in contact. It takes them from three to
five years to attain their growth. The blue crab (see Fig. 74, p. 101) is very
destructive to the young oyster.

One of the greatest enemics of the oyster is the starfish (see p. 55).
Other enemies (Fig. 57) are boring snails, boring sponges, and internal
parasites. One little erab (Pinnothe’res) which lives in the mantle cavity
scems to be an example of symbiosis rather than a parasite; at least it does
not appear to harm the oyster.

PELECYPODA 77

Oysters abound in quict, shallow inlets of the Atlantic coast south of
Cape Cod, and of the Gulf of Mexico. We have the best oysters in the
world.) Our most extensive oyster-beds are on the Chesapeake Bay, at
Baltimore, where they cover 3000 acres and furnish millions of bushels
yearly. We not only supply the markets of our own grewt cities, but send
large quantities to British markets. Oysters are found also on the Pacific
coast, on the coasts of Europe, of Australia,
and of Japan.

The scallop (Pecten) has an almost round,
fluted shell with a straight hinge without
teeth, and with unequal valves, one being
more nearly flat than the other. The shell is
usually brilliantly tinted. The foot is rudi-
mentary or altogether lacking. The mantle-
folds are fringed with slender tentacles and
the edge of each lobe is set with a row of
brilliant bluish ‘“ eyes.”” When at rest the
scallop lies on the sea bottom with its one ad-
ductor muscle relaxed and its shell open. If
disturbed, it quickly closes the shell by con-
tracting the strong muscle. This catches a
quantity of water which is forcibly ejected
through a round aperture at either end of the
ee of the hinge. The reaction
caused by forcing this water against the great : :
body of water outside propels the animal for- Fig. 56.—Right side of
ward. Thus, by rapidly opening and closing embryonic oyster, six days
its shell, it swims through the water with Old: m, Mouth; s, vent; J,
comparative ease. right lobe of liver; wl,

The edible scallop (Pec/ten irra’dians) is Velum. (Moore, Bull. U.
about 2} inches in diameter and its color 8. F.C., 1897.)
varies from a whitish to a reddish or purple
hue. The adductor muscle is the portion used by man for food. This
scallop is found on the Atlantic coast south of Cape Cod.

Pec’ten max/imus, found on the coast of Great Britain, in water 30 to 40
fathoms deep, is much larger. Its deeper shell was formerly used as a
baking-dish for oysters, hence the origin of the term “ scalloped oysters.”

The shell of another form common in the Mediterrnaean Sea (Pec’ten
jacobe’us) was worn as a badge by the crusaders returning from the Holy
Land.

The so-called pearl-oyster (Meleagri’na), which does not belong to the
oyster family at all, has a shell which is more nearly circular, a little convex,
and sometimes a foot in diameter. They are found in Madagascar,
Panama, Ceylon, East Indies, Australia, South Sea islands, Philippines,
and the West Indies.

Pearls are deposits of nacre formed about some foreign substance.
Prof. Jameson has discovered? by investigation upon the sea-mussel that,
in their case, pearls are caused by a parasitic worm (T'rematode). Pearls
are collected by divers who go down from 6 to 8 fathoms for them. Hun-

1 “On the coasts of Holland, Belgium, and France far greater care is taken
of their species (Os’trea ed’ulis) than we take of ours (Os’trea virginia’na),
but our natural conditions are superior to theirs.” —Linville and Kelly, p. 169.

2 Linville and Kelly’s ‘‘ General Zodlogy,”’ p. 173.

78 BRANCH MOLLUSCA

dreds of vessels are engaged in this industry. Pearls of various shapes are
found. Their colors may be white, yellow, pink, blue, red, green, or even

Fig. 57.—Some enemies of the oyster: 1, Drill (Urosalping cinerea);
g }

2, mussel (Mytilus edulis); 3, Sabellaria rulgaris: 4, periwinkle (Fulgur
carica). (Report of Fish Commision for 1897.)

black. Round lustrous white ones are most prized in Europe and America,
but those of the yellowish hue are preferred by Asiaties

PELECYPODA 79

Fig. 58.—Section of Anodon’ta, showing the digestive tube: m, Mouth;
g, gullet; J, liver; s, stomach; 7, 7, intestine; a, anus; p, pericardium; k,
kidney; s.c., chamber above the gills. (Furneaux.)

Fig. 59.—Anodon’ta, lying in one valve, with upper lobe of the mantle
removed: p, Pericardium; /, kidney; p.r., posterior retractor muscle;
p.a., posterior adductor muscle; a.a., anterior adductor muscle; a.r., anterior
retractor muscle; p.p., protractor pedis muscle; a, anus; e.s., exhalent
siphon; 7.s., inhalent siphon; /.m., cut edge of the mantle; 0.g., outer gill-
plate; m.l., mantle lobe; v.g., inner gill-plate; v, internal organs; f, foot;
l.p., labial palps; J, liver; p.l., pallial line. (Furneaux.)

Fresh-water mussels (Figs. 58, 59) or clams of our ponds, lakes, and
streams have firm leaf-like gills and two nearly equal adductor muscles.

80 BRANCH MOLLUSCA

The siphon is incomplete and the pallial line is entire, that is, without
sinus or indentation. The foot is long and compressed. The valves of
the shell are held together by the strong adductor muscles, and opened,
when these relax, by the elastic spring or hinge ligament. The shells are
a dull black on the outside, and pearly white, tinted with iridescent hues,
on the inside. The shell of the Unio is not so large and strong as that. of
Anodonta, while the latter genus has no hinged teeth. Clams ure found
in ponds and large streams (which do not dry
up in the summer), distributed along the direction
of the strongest currents to insure food supply.
They are partly buried in the mud, the open edge
of the shell down and the valves slightly apart,
with the fleshy foot protruding from the anterior
ventral margin. When disturbed, the foot and
edges of the mantle-lobes are retracted and the
valves tightly closed.

The shell is the mussel’s principal means of
defense. It has many enemies besides man, such
as the musk-rat, raccoon, mink, otter, and other
mammals that live in and about the streams
where the clam is found. Such animals as the
musk-rat gnaw off the hinge ligament to get the
shell open.

The young clams are carried in the gills, and
were formerly mistaken for parasites, and are
called glochidea. They differ much in shape from
the adult. The glochidea, or young clams, pass
out through the exhalant siphon and attach them-
selves by hooks on the valves to the gills or fins of
fishes, by which they are protected from enemies
and kept supplied with fresh water until suffi-
ciently mature for independent existence, when
they detach themselves from their host and drop
to the bottom of the stream.

The giant clam (Tridac’na gi’gas) of the tropics
has a shell from 2 to 4 feet long, which may
weigh from 300 to 500 pounds.

The soft-shelled clam (.\/1/’a arena’ria) abounds
in the mud flats of the Atlantic coast north of
: Cape Cod. The young clams swim about on the

Fig. 60.—Tere’dona- surface of the water. After the shell appears,
val’is, removed from its they sink to the bottom and attach themselves by
calcareous tube, with the byssus. When the clam is about 2 inch long,
elongated siphons. the byssus disappears and the animal buries itself
(Quatrefages. ) in the mud. As it grows, it keeps enlarging and

deepening its burrow until it may extend from
8 to 12 inches below the surface of the mud. The long siphons are extended
up to within reach of the sea-water, whose currents bring to the clam food
and air. The water enters through the ventral siphon, is driven through
the gills, and finally passes out through the exeretory tube, the dorsal
siphon.

Another form much used for food is the “© Quahog ”’ (Venus mercenaria),
which is characteristic of warmer waters, and is found from Cape Cod to
Texas. It burrows a little way below the surface, but is often found with

GASTEROPODA 81

its shell partly exposed. Along the Atlantic coast people use the Afya
or Venus for their ‘“‘ clam-bakes.’”” Many hundred bushels are used every
year for this purpose.

The razor-shell clams have similar habits. They are concealed in
vertical holes in the sand with the posterior end of the shell uppermost.
They have a powerful club-shaped foot, and can dig so rapidly that unless
one approaches very cautiously they escape from view. They seem to be
sensitive to light and to the ‘ jar’ made by approaching footsteps.

The borer (Pho’las) has its brittle but very hard shell marked like a file,
with which it bores into the hardest rocks. The united siphons are longer
than the rest of the body. Some forms are phosphorescent, emitting
bluish-white light.

The ship-worm (Tere’do) (Fig. 60), another borer, works into wood, doing
much damage to ships in the tropics. The larva enters the wood when it is
extremely small and enlarges the tunnel as it grows. The wood which
it excavates is not used for food, but is carried off by the excretory siphon.
Its food, which consists of microscopic organisms, is brought in by the
currents. The amount of damage these borers do seems incredible. They
completely honeycomb the hull of a wooden vessel. The best protection
against them is the sheathing of the hull with copper. Palmetto is the
best resistant among woods. The ship-worms caused the destruction of
a dam in Holland, threatening destruction to the country. Their dis-
persal is wide, since they are carried all over the world in the floating wood
which they attack. :

CLASS II. GASTEROP’ODA

These are asymmetric, usually univalve mollusks, and the
head region bears either one or two pairs of tentacles. As in
the snail (Fig. 61), the eyes are borne either at the bases or at the

Fig. 61.—A snail. (After Tenney.)

tips of the tentacles. The shorter tentacles are probably organs
of smell. The head contains the mouth, in which is the tongue,
covered by the radula, a ribbon-like organ supplied with
chitinous teeth and used for rasping the food.
The mantle is not divided into two parts as in the mussel, but
unites around the neck, leaving but a small respiratory aperture
6

82 BRANCH MOLLUSCA

into the mantle cavity. The foot is broad and flat and is used
for locomotion. Respiration is accomplished through the wall
of the mantle cavity, or by one or two plume-like gills or
ctenidia in the mantle cavity. In the air-breathing forms there
may be simply a pulmonary sac.

The shell is a spiral, either flat or elongated (Fig. 62), and is
usually closed by a flap or operculum (a horny plate growing
on the posterior portion of the foot) for protection.

whorls forming the spzre

body whorl

aperture

Fig. 62.—A snail shell. (Morse.)

Some Gasteropods are marine, some are fresh-water forms,
and still others are terrestrial.

The limpets (Patel’lide) are uncoiled forms with open conical shells.
They are found adhering to rocks between tide-marks. The foot acts as
asucker, enabling the animal to resist 2 foree of a thousand times its weight
when one attempts to detach it. The common limpct (Patella vulgata) is
used as food. It feeds upon scaweeds.

The ear-shells ( Haliot’/ida@), found on our western coast, have a row of

perforations near the margin of the shell through which the tentacles
pass to the exterior. The shells are much used in inlaid work on account
of their beautiful iridescent color. ‘They are also used as food, and the
shells are used for making buttons.
1 The cowries (Cypre‘idae) have richly enameled shells with small open-
ings. They are beautiful and are sold for ornaments, some species being
much prized. A beautiful yellow shell, an inch or less long, which abounds
in the East. Indices, is used as money in Siam and in parts of Africa: 6400
cowries are equal to about 36 cents. The cowries are tropical, but a few
species are found in temperate seas.

GASTEROPODA 83

The helmet-shells (Cassid’id@) are composed of layers of different colored
material and are used for carving cameos.

The tritons or sea conchs (7'rilon’ide@) have handsome shells, frequently
more than afoot in length. The shells of one specics is used by the South Sea
Islanders as a trumpet. The T'rilon’ide@ have a proboscis, a well-developed
siphon, and a short foot.

“The long, nearly cylindric shells of the Cavolinide make up much of
the * pteropod ooze’ of the deep seas.”

The common periwinkle (Littori’na) (see Fig. 57, p. 78) abounds on the
coast of New England and southward, where it is used as food. It is
a native of Europe. It is a vegetable feeder, and is valuable in cleaning
up the seaweeds from oyster-beds.

The oyster drill ( Urosal’/pinx ciner’ea) (see Fig. 57, p. 78) bores a hole
through the shell of the oyster and feeds upon its soft parts.

Natica is another drilling sea-snail common on our Eastern coast.
It burrows in the sand for clams and bores a hole with its radula, rotuting
its own body in the action.

The Nudibranchs.—In the Nudibranchs the shell is entirely absent in
the adult. True ctenidia are replaced as breathing organs by a number of
secondary branchixe, sometimes simple, sometimes branched processes or
leaf-like tufts, which may be distributed over the dorsal surface (as in
H’olis), or placed in a row on each side beneath the mantle-flap (as in
Pleurophylli’dia). These soft naked sea-slugs live in shallow water near
the shore, crawling about and feeding upon the seaweeds. Their protect-
ive resemblance is very great on account of both color and form. They
move very slowly. This also aids them in escaping the notice of their
enemies.

The land snails and slugs (Pulmona’ta) are air breathing. The air
enters the mantle cavity through a small opening which is near the right
side in the deztral forms (that is, the spiral of the shell turns like the hands
of a clock from left to right), and on the left side in the left-handed (sinis-
tral) forms.

Land snails ( Helic’ide) are common in moist woods. They come out at
night or in clouly weather to feed on succulent vegetation. When they
are numerous they do much damage. They, in common with the pond
snails, have thin spiral shells. They have two pairs of tentacles. The
uppor and larger pair bears the eyes at their tips, and the shorter pair is the
organ of touch. (See Fig. 61, p. 81.)

The land snail (Helix) has no operculum, and when frost comes it with-
draws into its shell, fitting the opening to some smooth object, and secretes
alayer of mucus. This hardens upon drying and forms a tough membrane.
the epiphragm, which closes the opening. In at least one species of Helix
a small hole is found just below the lung aperture, through which an ex-
change of gases may take place.

As a rule, snails lay their eggs in strings or masses, but the land snails
bury their eggs singly or deposit them thus in moist places. Snails are
used as food, being even shipped to the United States from Europe.

Land slugs (Limac’idw) are naked. The shell is vestigial and con-
cealed by the mantle. They have a rasping tongue like the snail’s. The
giant yellow slug of California reaches a length of 12 inches.

The Pulmonata are hermaphroditic. The garden snail hibernates by
coiling up in its underground burrow in winter.

Pond Snails.—The common pond snails have but one pair of tentacles,
and the eyes are situated at the bases of these. They breathe by means

S4 BRANCH MOLLUSCA

of a lung-sac instead of by gills, and must come to the surface occasionally
for air. In genus Physa the spiral of the shell is left-handed; in Limne’a,
right-handed, and in Planor’bis the shell is discoid or a flat spiral.

The eggs of genus Physa are deposited in gelatinous, transparent,
oblong capsules of an inch or less in length attached to submerged sticks
or leaves. Genus Limne/a lays the eggs late in spring in capsules sur-
rounded by a mass of jelly. The young puss through a metamorphosis.

still other pond or river snails breathe by means of gills. They live in
the bottom of ponds or streams and are carnivorous.

CLASS Ill. CEPHALOPODA

Class Cephalop’oda (head-footed) consists of such forms as the
squid, cuttle-fish, octopus, and nautilus. They are all marine,
and,inmanyrespects, the most highly developed of all mollusks.
There is a distinct head, bearing a pair of large well-developed
eyes, and surrounded by arms or tentacles which are modifica-
tions of the anterior margins of the foot.1. The posterior part of
the foot is transformed into a funnel-like siphon.

The body is bilaterally symmetric. Respiration is through
gills which line the mantle cavity. The shell may be external,
as in the nautilus; or internal, as the pen of the squid; or lacking,
as in the octopus.

They are usually carnivorous. Some are solitary, as the
devil-fish; others, as the squid, go in immense shoals. The
senior author has seen acres of ground covered with the
catches of them on the Pacific coast.

The circulatory system is closed and consists of a somewhat
complete heart and arteries, capillaries and veins.

The principal ganglia are grouped about the esophagus.
The nervous system is the most highly developed of any of the
branch, consequently they are the most intelligent of all mol-
lusks.

They have the power of quickly changing color to harmonize
with their environment.

Cuttlefishes are rapid-swimming Cephalopoda living at a depth of several
fathoms, but sometimes coming into shallower water. The cuttlefish has a
distinct head be: aring ten long arms, and a pair of highly developed eyes
resembling those of a fish. The free end of the head bears the mouth.
The inner surface of each arm or tentacle is flat and hears four longitudinal
rows of suckers. The fourth pair of tentacles is much longer and more
slender than the others, and the club-shaped end bears suckers. The

1See MeMurrich, p. 341.

CEPHALOPODA 85

body is covered by the thick integument of the mantle. The internal
shell is caleareous and furnishes the cuttlebone used for canary birds.

Cuttlefishes are carnivorous, feeding upon crabs, clams, or fishes.
They delight in the daylight and in the open sea, so they need to be pro-
tected from the view of their enemies. For this purpose they discharge
an inky fluid to cloud the water so as to escape detection. The dark-
colored secretion is carried in the ink-bag connected with the siphon.
The ink was used in ancient times as a writing fluid. The sepia ink used
by artists in making the sepia pictures is manufactured from this fluid of the
Sa The cuttlefish is also used as an article of food in the Old
World.

Fig. 63.—Loli'go vulga‘ris. (After Verany.)

Squids (Fig. 63) swim in schools. They, unlike cuttlefishes, are noc-
turnal. They are carnivorous, feeding upon young fishes. The common
squid is a foot or less in length. The internal shell is a horny “ pen”
shaped something like a feather, which is embedded in the dorsal portion
of the mantle. By alternately taking water into the mantle cavity and
forcing it out, the squid is driven rapidly backward. It avoids detection
by its color changes and by an inky discharge like that of the cuttlefishes.
It feeds upon small fishes and crabs, which it kills by biting with its power-
ful horny beak. Its enemies are large fishes and man. Giant squids are
over 9 feet long, with arms 20 or 30 feet in length.

The octopus is another member of this class. It has a short subspherical
body without any shell. It has eight sucker-bearing arms, with which it

86 > BRANCH MOLLUSCA

Fig. 64.—The chambered nautilus.

“Year after year beheld the silent toil
That spread his lustrous coil;
Still, as the spiral grew,
He left the past year’s dwelling for the new,
Stole with soft step its shining archway through,
Built up its idle door,
Stretched in his last-found home, and knew the old no more.

“Thanks for the heavenly message brought by thee,
Child of the wandering sea,
Cast from her lap, forlorn!
From thy dead lips a clearer note is born
Than ever Triton blew from wreathed horn!
While on mine ear it rings,
Through the deep caves of thought I hear a voice that sings:—-

“Build thee more stately mansions, O my soul,
As the swift seasons roll!
Leave thy low-vaulted past!
Let cach new temple, nobler than the last,
Shut thee from heaven with a dome more vast,
Till thou at length art. free,
Leaving thine outgrown shell by life’s unresting sea.”’
Oliver Wendell Holmes.

CEPHALOPODA 87

grasps its prey. ‘‘ Devil-fishes’”’ are found in allseas. They are gregarious
when young, but the adult is solitary. They creep about among the rocks
upon the extremities of their arms, generally moving sideways; or swim
rapidly, either forward or backward. The arms are somewhat webbed at
the bases.

Some devil-fishes measure 12 to 15 feet, others but a few inches. They
are found on our western coast and in the Pacific islands. They are much
used for food along the Mediterranean Sea and by the Chinese and Italians
of San Francisco.

The Nautilus (Fig. 64).—This Cephalopod has a many-chambered,
spiral, univalved shell, lined with pearly nacre, hence is often called the
‘pearly nautilus.” It has four gills instead of two. It crawls about
on the sea bottom by means of its many (about forty) small tentacles.
It has no suckers. The outer chamber of the shell is a large compartment
in which the animal lives. As it grows, the nautilus partitions off the space
behind it and moves forward. A calcareous tube containing the siphuncle,
a slender tubular continuation of the body, extends through all the septa.
The abandoned compartments are filled with air.

The nautilus has a beak and a rasping tongue, like those of the squid.
Each of its two disk-shaped eyes is attached by its convex side to a short
thick stalk. The aperture of the eye is small, and there is no cornea, no
iris, nor vitreous humor, but simply the retina at the base of a disk or pit.
The nautilus has not the power of changing its color, and has no ink sac.

It lives in the deep water in the south Pacific Ocean, and has been but
little studied. Many of the species of former ages are extinct. This is the
“ chambered nautilus,” immortalized by Oliver Wendell Holmes.

Economic Importance.—Mollusks are probably of more
direct use to man than any other invertebrate branch. The
oyster industry is of vast importance, giving employment to
thousands of persons and bringing an annual income of millions
of dollars. Clams are also used extensively for food, and peri-
winkles and snails less extensively. We get also pearls, and
the mother-of-pearl for the making of buttons, knife-handles,
and novelties. Factories have been established in Illinois and
Towa for making buttons on a large scale from the fresh-water
mussel shell. This industry threatens to exterminate these
bivalves unless means are taken to protect and perpetuate them.

The squid is extensively used as bait in cod-fishing, while
both the squid and the cuttlefish furnish the sepia ink used by
artists. The cuttlebone used for canaries is another product
of the cuttlefishes.

The ship-worm does much harm to dikes, wharves, and piles,
or any wooden structures which have been in water some time.

Important Biologic Facts.—The mollusks are the most highly
organized of any of the invertebrates except the Arthropoda,

88 BRANCH MOLLUSCA

and many zodlogists place them above the Arthropoda. They
have a well-defined circulatory system and nervous system and
especially highly developed eyes. They usually have a metamor-
phosis, some of the stages of which show indications of affinity
with ‘‘worms.”’

Classification.—
Class. Examples.
Pél’ecyp’oda. Sea-mussel, Oysters, Scallop,
Fresh-water mussel.
Gas’ terdp’oda. Limpets, Periwinkle, Snails.

Céph’/aldp’oda. Cuttlefish, Octopus, Nautilus.

BRANCH ARTHROPODA

ARTHROP’opA may be characterized as animals having bi-
laterally symmetric segmented bodies with jointed appendages
and a chitinous exoskeleton. The segments of the body are
not so numerous as in the worms.

This branch includes a vast assemblage of animals which
are widely distributed over the earth. They vary in habitat,
being aquatic, terrestrial, subterranean, aérial, or some com-
bination of these.

Some are of direct use in furnishing food for man, as the
lobster and the bee. Many cross-fertilize plants, and are thus
of indirect use to man. As common examples of this branch
may be named the lobsters, crabs, crayfishes, spiders, ‘‘ thou-
sand-legs,” and insects.

The digestive system is between the circulatory system and
the nervous system. It is not much coiled, but runs almost
straight through the body. (See Fig. 69.)

The circulatory system consists of a dorsal blood-vessel
open at the anterior end. The blood is pumped forward. It
fills all the irregular spaces of the body, through which it bathes
all the tissues and makes its way back to the dorsal vessel.
The corpuscles are colorless and ameboid.

The respiratory system consists of gills in the aquatic forms,
and of air-tubes or trachea in the insects and other terres-
trial forms.

The nervous system consists generally of a double chain of
ganglia, connected by a double nerve cord, running along the
ventral side of the body. (See Fig. 69, N.) Weshould expect
to find a pair of ganglia to each segment, but several ganglia may
beunited, as in the crayfish, where there are thirteen well-marked
ganglia, the three anterior ones uniting to form the so-called
brain.

Multiplication.—The sexes are usually distinct. Multiplica-
tion is generally by fertilized eggs.

89

90 BRANCH ARTHROPODA

CLASS I. CRUSTA’CEA

As examples of this class may be named crayfishes, lobsters,
crabs, and “ pill-bugs.”” The body has a limited number of
segments, about twenty in the crayfish. Each pair of append-
ages is regarded as being attached to a different segment.
The head and thorax are united and called cephalothorax.
The chitinous covering, rendered hard by deposits of carbonate
and phosphate of lime, is called the carapace.

Respiration is by gills, or branchie, though some breathe
through the skin.

The appendages are biramous, as seen in the swimmerets of
the crayfish. A typically developed appendage, as the third
pair of swimmerets, consists of a main stalk (protopod) and two
branches, the outer (exopod) and the inner (endopod). Several
of the appendages lack some of these parts. The student should
homologize the appendages and tell or demonstrate which ones
have missing parts.

The class Criista’cea is usually divided into two sub-classes,
the Hn’tomés’traca and the Mdél'acés’traca, with several orders
under each.

Sub-class Entomostraca is composed of crustaceans with a
varying number of joints or segments. They are usually small
or microscopic. There is a metamorphosis, the first stage being
the free-swimming nauplius.

Order I. Phyllép’oda are small aquatic crustaceans with
segmented bodies and leaf-like appendages. The brine shrimp,
fresh-water Branchipus, and Daphnia are examples of the
order. Daphnia is shelled and looks like a very small clam.

The animals of this order form an important part of the
food of fresh-water fishes. The eggs of many species can
resist the drought, which is a valuable means of perpetuating
them in small streams which dry up in summer.

Order II. Ostrac’oda are small crustaceans with apparently
unsegmented bodies enclosed in a bivalve shell, as the fresh-
water Cypris. The abdomen is rudimentary. There are only
two pairs of thoracic appendages, two pairs of maxillz, one pair
of mandibles, one pair of antenne, and one pair of antennules.
The antennez and antennules are used for locomotion. The

CRUSTACEA 91

antennules are also provided with olfactory hairs. Many of
this order are marine. Some, however, live in brackish or in
fresh water. They live usually at the bottom of their aquatic
habitat.

Order III. Copép’oda.—As examples may be named para-
sitic fish lice and the fresh-water cyclops. Respiration takes
place over the entire body surface.

The Cyclops (Fig. 65) is a small,
white, shelless animal with elongated
segmented body. It has a rather large
eye in the center of its head.

Order IV. Cirripe’dia or Barnacles.
—These fixed, marine, shelled crusta-
ceans are very abundant along the
seacoast, the rocks being covered with
them in places. Their food consists
of small animals in the water. One
may see thousands of barnacles snap-
ping their food as the waves and tides
dash over them.

Some forms attach themselves to
crabs, mollusks (Fig. 52), or even to
whales, while others are true external
parasites, sucking the juices of the ani-
mals to which they are attached. The
parasitic forms are extremely degenerate.

Since they have no power of loco-
motion by which to escape their ene- ;
mies, the barnacles (Fig. 66) are pro- ie ee - ie
tected by shells capable of ‘complete f, eggs. (Clark.) ;
closure.”” The body is flexed ventrally
and bears six pairs of cirri, which are used in straining small
organisms from the water and in carrying them to the mouth.
The mouth is surrounded by a pair of mandibles and two pairs
of maxille. Barnacles are hermaphroditic, but cross-fertiliza-
tion may occur. They have a metamorphosis, having first a
nauplius and then a cypris stage, the latter developing into
the fixed adult (Fig. 67). This order furnishes a good illus-
tration of the principle that inactivity leads to degeneration.

92 BRANCH ARTHROPODA

The barnacles (Lepas) are found in clusters on the bottom of
ships and often greatly impede their progress.

Fig. 66.—Anatomy of Lepas fascicularis (Packard): A, ¢, Six pairs of
legs or cirri; f, filamentary appendages; m, mouth; s, stomach; h, openings
of the liver (/) into the stomach, which is represented as laid open; i, in-
testine; a, vent; ¢, testis; v, vasa deferentia, one cut off; p, male appendage;
o, ovary; e, adductor muscle connecting the two basal valves; rs, scutal
valve; vc, carinal valve; vt, tergal valve. Enlarged twice. B, 1, Palpus;
2, mandibles; 3 and 4, first and second maxille. C, Nervous system: s,
Brain, sending the optic nerves to the rudimentary eve (¢), each optic
nerve having an enlargement near the eve, ?. ¢., the ophthalmic ganglion
(0); between o and a are the nerves which go to the peduncle; a, nerve
sent to the adductor scutorum; @, commissure between the supra- and
infra-esophageal ganglia (1); ¢, ¢, c, ¢, ¢, ¢, nerves to cach of the six feet.
Enlarged four times. (After Iingsley.)

Sub-class II. Mal’acés’traca is composed of crustaceans of a
definite number of segments, usually twenty—the head of five
segments; the thorax, eight; and the abdomen, seven. These

CRUSTACEA 93

segments are sometimes so fused as to puzzle one to distinguish
twenty segments, as in the crayfish, but by regarding one pair
of appendages to each segment one is able to count the number
of segments present in the specimen. There is a number of
orders under this sub-class, but only a few can be mentioned.
Order I. Phyllécar’dia is marine. The genus Nebalia, with
its bivalve carapace, its leaf-like thoracic feet, and biramous

Fig. 67.—Three adult crustaceans and their larve: a, Prawn (Peneus),
active and free living; 6, larva of prawn; c, Sacculina, parasite; d, larva of
Sacculina; e, barnacle (Lepas), with fixed quiescent life; f, larva of barnacle.
(After Hackel.) (From Jordan and Kellogg, ‘‘ Animal Life,’ D. Appleton
and Co., Publishers.)

abdominal appendages, may be taken as an example of this
order.

Order II. Décdp’oda.—This order consists of both marine
and fresh-water crustaceans. It contains the best-known forms
as well as the most useful ones to man, as the crayfish, lobster,
shrimp, prawn (Fig. 67), and crab. As the ordinal name sug-

94 BRANCH ARTHROPODA

Fig. 68.—Astacus fluviatilis. Ventral or sternal views (nat. size).
A, Male; B, female: a, Vent; gg, opening of the green gland; lb, labrum;
ml, metastoma or lower lip; od, opening of the oviduct; vd, that of the vas
deferens; 1, eye-stalk; 2, antennule; 3, antenna; 4, mandible; 8, second
maxillipede; 9, third or external maxillipede; 10, forceps; 11, first leg;
14, fourth leg; 15, 16, 19, 20, first, second, fifth, and sixth abdominal ap-
pendages; x, xi, xiv, sterna of the fourth, fifth, and cighth thoracic somite;
xvi, sternum of the second abdominal somite. In the male, the 9th to the
14th and the 16th to the 19th appendages are removed on the animal’s
left side; in the female, the antenna (with the exception of its basal joint)
and the 5th to the 14th appendages on the animal's right sre removed;
the eggs also are shown attached to the swimmerets of the left side of the
body. (Huxley.)

CRUSTACEA 95

gests, they have ten “feet.” The first pair is very large and
armed with large strong pincers or chele, for defense or for
securing their prey. Their eyes are on movable stalks and
can be withdrawn under the rostrum or beak for protection.
The anterior thirteen segments are covered by a chitinous
calcareous shield called the carapace.

The Crayfish (Fig. 68) is the best known inland example
of this order. The twenty segments may be discerned by
counting one segment to each pair of appendages, which are
arranged in the following order: one pair of antennules, one
pair of antenne, one pair of mandibles, two pairs of maxille,
three pairs of maxillipeds, five pairs of legs, six pairs of swim-

Fig. 69.—Longitudinal section through Astacus fluviatilis: C, Heart;
Ac, cephalic aorta; Aa, abdominal aorta; the sternal artery (Sta) is given
off close to its origin; Am, masticatory stomach; D, intestine; L, liver;
T, testis; Vd, vas deferens; Go, genital opening; G, brain; N, ganglionic
cord; Sf, lateral plate of the caudal fin; 0, eye stalk. (Huxley.)

merets, or nineteen pairs of appendages and a terminal segment
without appendages, called the telson, which contains the
vent or posterior opening of the alimentary tube.

Its locomotion on four pairs of legs may be forward, sideways,
or backward. Its backward locomotion by its ‘ tail fin”
is probably its best and most rapid mode of locomotion.

Digestion.—The food is seized by the cheliped and may be
conveyed directly to the mouth, or, after being torn into bits,
may be transferred to the pincers of the second and third pairs
of legs and from there to the mouth. The jaws move from side
to side instead of up and down. From the mouth the food
passes into the esophagus, which is very short, as the stomach
is in the head (Fig. 69). In the inner walls of the stomach

96 BRANCH ARTHROPODA

are three “teeth” or hard processes which are controlled
by muscles attached to them and to the carapace. By the
action of these muscles the food is ground between these teeth,
which are sometimes called the
‘gastric mill.’ In the poste-
rior part of the stomach there
is a serics of filaments or stiff
hairs which prevent any coarse
or unground food from passing
into the intestine. So the
stomach is a masticating rather
than a digestive organ. When
the food is ground fine it passes
into the intestine, a straight tube
extending from the stomach to
thevent. The food is acted upon
by the digestive fluids from the
glands which lie on each side
of the stomach and whose ducts
enter just back of the stomach.
Digestion and absorption take
place in the intestine.
Circulation —When the heart
(Fig. 71) contracts the blood
flows both forward and back-
ward. Five tubes, or ‘ arteries,”

Fig. 70.—Astacus fluviatilis. A
male specimen, with the roof of the
carapace and the terga of the ab-
dominal somites removed to show the
viscera (nat. size): aa, Antennary
artery; ag, anterior gastric muscles;
amm, adductor muscles of the mandibles; cs, cardiac portion of the stom-
ach; gg, green glands; 4, heart; hg, hind gut, or large intestine; Lr, liver;
oa, ophthalmic artery; py, posterior gastric muscles; saa, superior abdominal
artery; , testis; rd, vas deferens. (Huxley.)

carry it forward, and two, backward. These “ arteries’ keep
dividing until they form minute capillaries with open ends.
The blood runs into the irregular body spaces, or sinuses, and

CRUSTACEA 97

bathes the tissues, then goes into the larger median ventral
sinus below the thorax and abdomen, from which it is conducted
to the gills. After being conveyed to the gill filaments, where
it is aérated, it is returned to the heart through the pericardial
sinus. The blood enters the heart, or dorsal vessel, through
three pairs of openings, one on each side, a pair on the top, and
another pair below. Valves prevent the blood from returning
through these openings.

qt A vr i
‘| rT sy) il

pl Hany

Fig. 71.—Astacus fluviatilis. The heart (x 4). A, From above; B,
from below; C,from the left side: a.a., Antennary artery; a.c., ale cordis,
or fibrous bands connecting the heart with the walls of the pericardial
sinus; b, bulbous dilatation at the origin of the sternal artery; h.a., hepatic
artery; l.a., lateral valvular apertures; 0.a., ophthalmic artery; s.a., superior
valvular apertures; s.a.a. superior abdominal artery; sf.a., sternal artery,
in B cut off close to its origin. (After Huxley.)

Respiration—The plume-like gills are attached to the
basal joints of the legs. They are situated in partially
closed chambers between the body wall and the carapace.
The water is drawn in and out by the “ gill-bailers,” parts of
the second maxille, in their vibration back and forth. In
passing over the gills the water is separated from the blood by
an extremely thin membrane. Through this membrane the
carbon dioxid is thrown off and oxygen taken into the blood.

Nervous System.—Several ganglia unite to form the supra-

t

98 BRANCH ARTHROPODA

esophageal ganglion or ‘brain,’ from which a nerve cord
passes on each side, uniting below the esophagus in a double
(apparently single) ventral nerve cord (Fig. 69), which ex-
tends the whole length of the body and connects the ganglia.
We should expect to see a ganglion for each segment, but there
are but thirteen ganglia, some of these being formed from a
union of several. On each side of the esophagus is a large gang-
lion; there are five more ganglia in the thorax and six in the
abdomen.

The stalked eyes are compound, being composed of many
facets. The sense of touch is well developed. The surface
of the body is sensitive and the antenne are especially adapted
for ‘‘ feelers.’”’ The sense of smell is thought to be seated in the
hairs or sete on the antennules.

Multiplication —In the spring the little brown or black eggs
may be found attached to the swimmerets of the female.
For some time the young crayfishes, by means of hooks on
their claws, cling to the swimmerets of the mother for protec-
tion.

Molting.—The young crayfish, which is of much the same ap-
pearance as the adult, grows rapidly. Since the shell is hard
the animal cannot enlarge except when it sheds its skinor molts,
which it does periodically. Even the hard lining of the stomach
is cast. Growth takes place while the new skin or shell is form-
ing.

Restoring Lost Parts. —Crayfishes have the power of growing
a new leg to replace one broken off by accident or in a fight.
This accounts for the unequal size of the chelipeds in many
specimens.

Habits. —Crayfishes inhabit fresh-water streams and ponds,
lurking under stones or ledges in daytime and feeding at night.
When the streams dry up, they dig holes in the ground until
they reach water. These are sometimes many fect deep.
The clay dug out around the hole is deposited in a ‘* chimney.”
In these holes they probably live till the next spring. Some
species do not live in the water, but burrow in the soft moist
earth, and one species has been found in the sea. Crayfishes
are omnivorous, eating anything they can get, but they prefer
worms, insect larve, and snails,

CRUSTACEA 99

The protective resemblance is excellent, the colors varying from
a delicate pink or tan to a dark green or purple.

Use.—Crayfishes are used by the million in France, and to a
limited extent in the United States, for food. They also furnish
food for fishes. Raccoons, muskrats, and crows prey upon
them.

The lobster (Fig. 72) is marine and is very much like the
crayfish, only much larger. Specimens weighing twenty-five

Fig. 72.—A small lobster (dorsal view) mounted on a glass so as to show
both dorsal and ventral views. Students’ work.

pounds have been captured. Among the invertebrates the
lobster ranks next to the oyster as an article of food for man.

Prawns and shrimps look like our common crayfish and are
used to some extent for food. They are small. The common
prawn (Palemone’tes vulga’ris) is about 2 inches long. It is
transparent, so that the viscera can be seen through the thin
leathery carapace.

100 BRANCH ARTHROPODA

Hermit Crabs (Fig. 73).—There are a number of spécies of
hermit crabs which are not true crabs, but are more like the
lobster and crayfish. They have the habit of backing into
empty univalve shells which they carry about with them and
into which they may withdraw for protection. This habit has
resulted in a soft-skinned, reduced abdomen, with a spiral
twist and with no appendages except a pair of hooks for hold-
ing on to the inside of the shell. The abdomen is always hidden
in the shell. The head, thorax, and legs project when the
animal is active, but are withdrawn when danger approaches.

Vig. 73.—Hermit crab (Pagu’rus) in shell, with a sea-anemone (Adam'sia
pallia’ta) attached to the shell. (After Hertwig.) (From Jordan and Kel-
logg, “ Animal Life,” D. Appleton and Co., Publishers.)

As it grows it discards its shell and hunts a larger one. Some
of these hermit crabs have a peculiar commensal life with cer-
tain sca-anemones (Fig. 73), which they carry about on their
shells. If the sea-anemone becomes detached the crab hunts
another and places it on its shell. The crab is protected from
its enemics by the stinging threads of the anemone, also hy
its resemblance to the seaweed, while the anemone is assured
of a fresh food supply by being carried from place to place by
the crab.

Crabs are other examples of this order. The cephalothorax

CRUSTACEA 101

is much broader than that of the crayfish, and the abdomen,
which is used only to protect the eggs of the female, is folded
under the cephalothorax. They are great scavengers. Many
kinds are used as food. One of the best for this purpose is the

Fig. 74.—Successive stages of the molting of one individual of the blue
crab, Calli’nectes sa’pidus. (G. Hay, in Doc. 580, Bureau of Fisheries.)

edible or “blue crab” (Callinectes sapidus), great numbers
of which are caught along the Atlantic and Gulf coasts.
They are best liked for food just after their molting (Fig.
74), and are then called “ soft-shelled crabs.” They are

102 BRANCH ARTHROPODA

sometimes called ‘‘ swimming crabs”? because they have the
last pair of thoracic legs flattened and paddle-like, adapted
for swimming sideways quite rapidly. They have large sharp
lateral spines. The strong chelipeds are adapted for cutting.
Hach of the other thoracic appendages ends in a point with no
forceps.

The little ‘‘fiddler-crab” lives in salt marshes along the Atlantic coast.
The male has one big and one little cheliped, which he brandishes grotesquely
when disturbed.

The spider crab (.Macrochei'ra) of Japan sometimes measures from 12 to
16 feet from tip to tip of legs, but the body is only a few inches—about a
foot—in width, making them very peculiar creatures. At a little distance
they look like immense sprawling spiders.

The little oyster crab, found so often in our dish of oysters, does
no harm to the body of the oyster, but its life within the shell insures its
food being brought to it by the currents of water made by the oystcr to
bring its own food. This is a case of commensalism! where there is a decided
advantage to one animal and none, so far as known, to the other, yet the
intruder does no harm.

Order III. Arthrés’traca comprises both marine and fresh-
water forms. The first thoracic segment, and sometimes the

Tig. 75.—Beach flea, Gam’marus orna’tus. (After Smith.)
£ )

second, is fused with the head and bears maxillipeds. The eyes
are usually sessile. Gammarus (Fig. 75) is a fresh-water form.

The Pill-bug.—If one searches under old boards or logs he
will find a small gray or brownish fourteen-footed crustacean,
truly terrestrial, with depressed body and with gills on the ab-
dominal appendages. It is called *‘ pill-bug”’ from its habit

1See Jordan and Kellogg’s “ Evolution and Animal Life,” p. 370.

ARACHNIDA 103

of rolling up into a ball when surprised. Its protective resem-
blance is good. Its locomotion is by crawling or running.

Some of the marine Arthrostraca are parasitic on crabs and in
the mouths of fishes.

CLASS II. ARACH’NIDA

Arachnids are arthropods with the head and thorax generally
fused into a cephalothorax, bearing six pairs of appendages.
The first and second pairs are for biting. Then follow four
pairs of walking legs. There are no antenna, the eyes are simple,
and the abdomen is apodal.!

The abdomen varies much. It is
short in the spiders, long in the
scorpions, or is fused with the
thorax, forming a stout body in
the mites.

They are usually oviparous. How-
ever, some scorpions and some mites
are viviparous. They are generally
terrestrial, but some live in the
water. There is no well-marked
metamorphosis.

Order I. Scorpion’ida.—Scorpions
(Fig. 76) are arachnids with long
slender bodies ending in a poison
fang. The head and thorax are
fused and bear several pairs of
jointed appendages. The abdomen
consists of a broad anterior and a
narrower posterior portion. There
are several pairs of eyes.

Respiration is by means of four pairs of lung-sacs opening
on ventral side of abdomen from the third to sixth segments.

Food.—They are carnivorous, feeding upon spiders and in-
sects, which they seize with their pincers and sting to death.

Multiplication —They are viviparous. The mother cares
for the young with great solicitude, carrying them about at-
tached to her body.

Fig. 76.—Carolina scor-
pion (Bu’thus carolinia’nus).

1 See Glossary.

104 BRANCH ARTHROPODA

Size.—One giant species in Ceylon is 12 inches in length,
while American species are about 4 inches long.

Habits and Distribution—Scorpions are nocturnal. They
live in tropical and subtropical countrics. Their sting is
dreaded by man, but seldom proves fatal. About twenty species
are found in North America.

Order II. Phalangid’ea——The members of this order look
like long-legged spiders, with small bodies. Closer observation
shows that the abdomen is fused with the thorax and not

' Fig. 77.—Parts of a spider. 1, Under part of a spider’s body: t, Thorax,
or chest, from which the eight legs spring, and to which the head is united
in one piece; f, fangs; p, palpi, or feelers, attached to the jaws; a, abdomen;
b, breathing-slits; s, six spinnerets with thread coming from them. 2,
Front of spider’s head: c, Eyes; p, palpi; l, front legs; hk, hasp of fangs;
f, poison-fangs; j, outer jaws. (From Holder’s “ Zodlogy,’”’ American
Book Co., Publishers.)

joined by a pedicel, as in the spiders. The ‘ harvest-man ”
or ‘‘ daddy-long-legs”” is a familiar example. It frequents
shady places and feeds on small insects.

They are a dull color, to fit their environment. So long as
they remain motionless their protective resemblance conceals
them very effectively from their enemics. The respiration is
by trachee.

Order III. Arane’ida, or Spiders (Fig. 77).—These are
arachnids with unsegmented abdomen joined by a pedicel to
the thorax.

ARACHNIDA 105

Appendages.—There are two pairs of mouth-parts. The
mandibles or chelicere are strong and composed of two por-
tions, the basal falx and the sharp-pointed fang, in which is a
small opening, the outlet of the poison gland. The palpi are

Fig. 78.—The bird-spider (Myg’ale avicular’ia) capturing a humming-bird.
(From Holder’s “‘ Zodlogy,’’ American Book Co., Publishers.)

long and limb-like and are often mistaken for a fifth pair of
thoracic legs. The basal joints are broad and adapted for
chewing the food. They are called the maxille. Then follow
four pairs of seven-segmented legs used for locomotion. The
spinnerets on the abdomen are homologous to paired appendages.

106 BRANCH ARTHROPODA

Color —Almost all spiders are covered with hair. The color
is partly in the skin and partly in the hair. The most common
colors are grays and browns, but the colors are very varied, and
in some species, as the jumping spider, they are almost as
bright and gorgeous as those of butterflies.

Foods and Feeding.—Thcey are generally carnivorous, sucking
the juices from their prey. Some spiders spin webs, others do
not. The spider’s thread is composed of many fine threads,
each passing from the body by a separate tube and then unit-
ing. The united thread forms a cord finer than the finest silk
of the silkworm, hence it is often used for the ‘‘ cross-hairs ”’
of the telescope.

Respiration is by lungs or lung-sacs containing bookleaf-
like plates, and by trachez.

Senses.—The sense of sight is well developed, but they seem
to be shortsighted, seeing clearly only at a distance of 4 or 5
inches. The palpi are organs of touch.

Dimorphism.—Male spiders usually have longer legs and
smaller bodies than the females.

Sub-order Tét’rdpnet/ménes.—These spiders have four lungs
and cight eyes. The most important members of the group
spring upon their prey, often catching mice and small birds
(Fig. 78). The large, dark, hairy spiders (Wyg’ale) found in
bunches of bananas belong here. The claws of the mandibles
or jaws work up and down instead of from side to side.

The trapdoor spiders (Cten?’za) of the Southwest dig tunnels
in the soil, line them with silk, and cover them with a close-
fitting hinged lid.

Sub-order Dipneu’mones.—The members of this sub-order
have two lungs and a pair of trachee. This group includes
the majority of living spiders.

The ground spiders (Dras’sidir) do not spin a web, but hunt their prey
at night. Many specics make silken tubes in which they lay their eggs or
hide when molting or in winter. An eastern species lives in a bag of silk
hidden under stones.

The tube-weavers (CIubion’ida).—These are also species which spin no
web. In summer they live in flat tubular nests on plants, sometimes
Hi rolled leaves. In winter they live in tubular nests under bark and
stones.

The Funnel Web Weavers (:Agalen’ida@).—They weave a concave sheet
of silk with a funnel-like tube on one side, and with threads extending in

ARACHNIDA 107

all directions attached to blades of grass for support. In the morning dew
these webs form a shimmering silken sheet. The spider runs about on
the upper surface of the ‘ sheet ” and catches any insects which light upon
it. The tube or hiding place opens below, so that the spider can escape if an
enemy appears upon the web. These are long-legged brown spiders, of
which the common grass spider is a familiar example.

The ‘‘curled-thread weavers” are of two kinds, those which spin regular
webs and those which spin irregular webs. The curled thread is composed
of silk spun from a special organ, the cribel’/lum, in front of the spinnerets.
It is combed into shape by means of stiff hairs called the calamis’trum on
the metatarsus of the hind legs, as the spider moves the hind legs rapidly
back and forth.

Those spiders which spin irregular curled threads (Dictyn’idz) usually
make variously shaped webs on fences, under stones, in rotten logs, or upon
plants having clusters of small flowers like the golden-rod.

There are but two genera of these spiders which spin regular webs
(Ulobor’idz). The “triangle spider ”’ is found all over the country in pine
woods. Its web is usually stretched between the twigs of a dead branch
of pine or spruce, and consists of four plain radiating lines and a series of
double cross-lines. The spider, which rests near one of the twigs from which
a strong line is drawn to one of the other twigs, pulls the web tight, so that
the cross-lines are separated as far as possible. When an insect lights
upon one cross-line the spider suddenly lets go, so that the whole web springs
forward and the insect becomes tangled up in the other cross-lines.

The cobweb weavers (Theridi’ide) build their webs, which are ap-
parently only a shapeless maze of threads, in the corners of rooms—as the
house spider—or out in the fields between the leaves of bushes, or in the
fence corners, or among rocks. They are generally rather light colored,
small, and soft. They live in their webs, hanging by their feet, with the
back downward. The cocoons, several of which are made in one season,
are soft and round and hang in the web.

The orb weavers (Epei’ride) construct some of the most wonderful
homes built by any animal. First, there is an irregular outer framework of
supporting lines; then there is a number—from twelve to seventy—of dry
and inelastic lines radiating from the center. There is an inner spiral of
these inelastic threads which begins at the center and winds outward.
The rings of this spiral are about as far apart as the spider can reach.
Its use is merely for support. The spider then begins at the outermost
part of the web and spins an outer spiral of sticky elastic threads, winding
inward, the concentric circles being close together. As it becomes neces-
sary, in forming this outer spiral, the threads of the inner spiral are de-
stroyed. When an insect touches one of the outer sticky threads the thread
not only sticks to it, but it stretches so that the insect becomes tangled up
in the other circles, which is all the easier to do since the threads are so close
together. Many species strengthen the web by spinning a zigzag ribbon
across the center. The making of the entire web seems to be done alto-
gether by feeling and can be done in the dark as well as in the daylight.

Most of the orb-weaving species have large, nearly spheric abdomens and
stout legs, sometimes ‘“‘ with humps and spines.” These spiders are often
brightly colored, the colors of the abdomen being arranged in a triangular
or leaf-shaped pattern. Some species live near the center of the web,
hanging head downward, others hang back downward near one edge of the
nest. In some species the male is smaller than the female.

108 BRANCH ARTHROPODA

The crab spiders (Thomis'idw) are so-called because of their short broad
form and peculiar habit of walking sidewise or backward. ‘ They spin
no webs, but lie in wait for their prey.”! Some brightly colored species
conceal themselves in flowers. Their protective resemblance is so good
that insects visiting the flower often light within reach of the spider before
seeing it. They live about plants and fences and hibernate in winter under
stones and bark.

The jumping spiders (At/tid@) have stout bodies and short legs, bright
colors, and conspicuous eyes. They jump quickly sidewise or backward
for a long distance. They make no webs except those in which they hiber-
nate or lay their eggs.

The Running Spiders (Lycos’idw).—These are the familiar hairy dark-
colored spiders found under stones and logs. They depend upon their
specd for the capture of their prey and run very swiftly. They resemble
in appearance and habits the so-called tarantulas of the Southwest, but are
smaller. The claws of their mandibles move horizontally. Their cyes are

Fig. 79.—Female spider with young ones. (Cooper.)

of different sizes. Some of these spiders build tubular nests in the ground
and line them with silk. They sometimes conceal the entrance with leaves
and sticks. They often drag the egg-sac, a large gray ball, after them. In
genus Lyco’sa the young (Fig. 79) climb upon their mother's back. The
female of another genus, Dolome'des, carries the egg-sac ‘in her mandibles
until the young are ready to hatch, when she fastens the sac in a bush and
spins a web of irregular thread about it in which the young remain for a
time.

Order Acari’na.—These arachnids have stout bodies, there
being no apparent segments, the abdomen being united with the
cephalothorax. There is no heart nor blood-vessels. The res-
piration is performed by means of trachew. They are gencrally
Oviparous; some are viviparous. Many are parasitie (Fig. 80).

1 Comstock.

ARACHNIDA 109

The mouth parts are more or less united to form a beak. The
common red mite sucks the juices of the house plants which it

Fig. 80.—The chicken mite (Dermanys’sus galli’ne): a, Adult; b, tarsus;
c, mouth parts; d and e, young. All much enlarged. (Osborn, U.S. Bu-
reau of Ent., 1907).

Fig. $1.—Cattle tick (enlarged). (After Salmon and Stiles.)

infests. One mite (Dem’odez) is parasitic in the hair-follicles of
the dog, cat, sheep, cow, horse, and man. Another mite

110 BRANCH ARTHROPODA

(Sarcop'tes scab’e?) is the itch mite, causing the disease called the
itch. Still another is called the cheese-mite.

Ticks (Ixo'des) are parasitic, blood-sucking Acarina which
attack man and other mammals. They do not exceed a centi-
meter in length, the males being the smaller. The so-called
“Texas fever” of cattle is transferred by the common cattle
tick (Fig. 81).

—— Sees ese

Fig. $2.—Horseshoe or king crab (slightly damaged on left). (From
specimen.)

OrderIV. Xiph’osu’ra.—The Lim’ ulus, or horseshoe crab (Fig.
82), is a marine arachnid living on the bottom of the sea in
shallow water, creeping along in the mud and sand and feeding

MYRIAPODA 111

on worms. The body has a chitinous covering. The cephalo-
thorax is arched and bears the large compound eyes and two
simple eyes. The abdomen is almost hexagonal and ends in a
long caudal spine. On the ventral side of the cephalothorax
are six pairs of appendages, used for securing food and for
locomotion. The last pair, the operculum, is broad and leaf-
like and covers the five pairs of leaf-like branchial appendages
of the abdomen. These appendages are for respiration. The
shape of the body, its hard covering, marginal spines, and its
color, which harmonizes with its environment, afford it ample
protection and defense.

There are several other orders, but these will suffice for our
purpose in the present work.

CLASS III. MYRIAP’ODA

The name indicates myriad footed, hence the common name,
thousand-legs. A myriapod is a worm-like tracheate arthropod
with a distinct head, a round or flattened
body composed of many similar segments,
to each of which is attached one or two pairs
of appendages. Myriapods have one pair
of mandibles, one pair of antenne, and
numerous ocelli. ‘A few species are injur-
ious to agriculture, while others are to be
classed among our friends.”

Order I. Chilop’oda.—These are myria-
pods with the body flattened, with fifteen
to one hundred and seventy or more seg-
ments, each bearing a single pair of legs,
and with long, many jointed antenne (Fig.
83). The mouth parts are adapted for bit-
ing. The opening of the poison gland is
on the first pair of legs, which are used
with the mouth parts. This order includes
the centipedes, as Litho’bius, common under
stones. The bite of the true centipede
(Scolopen’dra) is fatal to insects and to
other small animals, their prey, and painful or even dangerous
to man.

Fig. 83.—A_ centi-
pede.

112 BRANCH ARTHROPODA

Order II. Diplop’oda.—These are myriapods with dorsally
convex bodies. Each apparent segment, beginning with the
fourth or fifth, bears two pairs of appendages. There are no
poison fangs. The antenne are short and few jointed. This
order includes the millipeds. An example is Iulus. They
are found under old stumps or about rotten logs. Their food
consists usually of decaying vegetable matter, but some forms

Fig. 84.—Class collecting insects.

feed upon growing plants, otherwise they are harmless. They
have a habit of rolling up into a helix-like coil when disturbed.

They are bisexual. When hatched the young have but three
pairs of legs. ‘‘ By successive molts new segments and append-
ages are added ” until the adult form is reached.

CLASS IV. INSEC’TA

This class of Arthropoda comprises a very large number of
species. Three hundred thousand, according to Kellogg, are
known.

INSECTA 113

Habits and Habitat.—Insects vary in their habitat. Most
of them are terrestrial, some are aérial, others are aquatic, a
few even being marine, while still others are subterranean.

Labrum (a)

0 Mandible i
Tarsus\ Palpus ;
uP
Tibia Maxilla
Palpus ka
Par ci Y

ores ae
Trochanter 7 3 YF 71 B Dockattine
(ee:

Prothorax i

Mesofthorax ate
os |-Seute =)
o a rellum ———<

f-]

Hind Wing

Fig. 85.—External anatomy of Calopte’nus spre'tus, the head and thorax
disjointed: up, Uropatagium; f, furcula; c, cereus. (Drawn by J. 8.
Kingsley.) (From Packard’s ‘ Zodélogy,’’ Henry Holt & Co., Publishers.)

Some are diurnal, as our common butterflies; others are noc-
turnal, as the bed-bug; some, crepuscular, as the moths. Some
are solitary; others gregarious, or social, as the ants and bees.

Plan of Structure (Fig. 85).—The insect body is divided into
three well-marked regions—the head, thorax, and abdomen.

8

114 BRANCH ARTHROPODA

The head bears the compound eyes and simple eyes (when they
are present), one pair of antenna, and three pairs of mouth
parts, which vary according to the character of their food.
Hence the mouth parts may be adapted for chewing, lapping,
sucking, or piercing—“ all referable back to the chewing type.
These are, in turn, modified legs.’”!

The thorax has usually three well-marked segments—pro-
thorax, mesothorax, and metathorax—as in the grasshopper.
Each segment bears a pair of jointed ventral legs. The two
pairs of wings, when present, are outgrowths of the dorsal por-

=

Fig. S6.—“ Look out!”
tion of the meso- and metathorax. Sometimes there is but
one pair, and in a few cases none.

The abdominal segments vary in number and usually bear
no paired appendages except, sometimes, on the terminal seg-
ments.

Covering.—Over the greater portion of the surface of the body
the cuticle or external layer of the skin is made firm and horny
by a substance called chitin. This forms an exoskeleton for the
protection of the soft parts within, and, by its rough interior
surface, provides points of attachment for the numerous small
but strong muscles.

! Kingsley’s Hertwig, “ A Manual of Zodlogy.”

INSECTA 115

Those portions of the cuticle which do not contain much
chitin are easily bent, thus permitting motion between the
segments of the body and of the appendages.

All insects have hairs scattered more or less abundantly or
regularly over the body. In Lepidoptera the hairs are modified
into scales, as is shown on the wings of a butterfly, where “ all
the gradations from hair to scale can be found by going from
the base out to the distal area of the wing.’”!

Self-defense (Fig. 86) is by various methods and organs,
which will suggest themselves to the student from his past
experience. When insects cannot sting or bite, they often

Fig. 87.—Al’aus ocula’tus and larva, showing eye-spots. (After Harris.)

defend themselves by threatening attitudes. In some cases
one is reminded, at first sight, of a snake’s head, and retreats
in terror. The “ eye-spots”’ (Fig. 87) and “ horns” (Fig. 88)
on many insects are probably for the purpose of terrifying ap-
pearance.

Protective Coloration.—Insects attract attention by the
variety and intensity of their colors and by their numerous,
interesting, and often beautiful cclor-patterns. Many natural-
ists believe, and have confirmed their opinions by observation
and experiment, that the variety of color and color-patterns of

1 Kellogg, p. 592.

116 BRANCH ARTHROPODA

insects and of other animals is indirectly due to two causes:
first, the advantages given to the individual or species in the
struggle for existence by these specific colors and color-patterns,
which—as in the case of the gray moth on the tree-trunk or
the katy-did among the green leaves—helps to conceal them

Fig. SS.—Larva of regal walnut moth (Cithero’nia rega’lis) extended (two-
thirds nat. size). (Photographed from life.)

from their enemies by affording protective resemblance, or—as
in the case of the bumble-bee or the milkweed butterfly—to
warn the enemy of the danger of sting or of the disagreeable odor
and taste. The advantage gained is easy to be seen in each

Fig. S9.—Pupa of regal walnut moth (three-quarters nat. size). (From
life.)

case. They believe that these particular color-patterns are
due, in the second place, to gradual development ‘ through
natural selection of naturally occurring, advantageous varia-
tions.”

The direct cause of color may he chemical, depending on the

INSECTA 117

chemical composition; or physical, depending upon the structural
or physical make-up; or it may be due to a combination of
both of these. In the most highly colored group of insects,
the Lepidoptera, the color is due to the chemical substances
(pigment granules), to the structural character of the scale

Fig. 90.—The protective resemblance of the leaf-butterfly (Kal’/lima).
(Holder, after Wallace.)

walls (striz), and to the overlapping (lamination) of the scales
laterally, as well as to the overlapping of the tips of the scales
in one row over the bases of the scales of another row.

“ The blacks, browns, yellows, and dull reds of butterflies and
moths are produced chiefly by the pigments (chemical colors),
while the brilliant metallic colors, the iridescent blues and

118 BRANCH ARTHROPODA

greens, . . . are due to the structural or physical make-up of the
scale covering.”’!

Variable Protective Resemblance—Often the different indi-
viduals of the same species are of slightly different colors, the
colors varying to harmonize with the particular environment
of the individual during its development, being fixed in the
adult.

Special protective resemblance (Fig. 90) is illustrated by
Kallima, which resembles a dead leaf, and Phyllium, resembling
a green leaf (Fig. 91), and, more commonly, by the measuring-
worm, as it holds the body out stiff, imitating a short or broken
twig. Thus in many cases ‘ the insect’s appearance simulates
in more or less nearly exact ways some par-
ticular part of the habitual environment.”

Warning colors are possessed by many
insects having a special organ of defense
—as the sting of that wonderful little
stimulator, the hornet—or a disagreeable
taste or odor, as that of the milkweed or
“monarch”? butterfly (Anosia plerippus)
(Fig. 92, a). Other examples of insects
having conspicuous or warning colors are
the black and yellow wasps and bees, the
lady-bird beetle, and the swallow-tail but-
terflics. Many others might be mentioned.
_Fig. 91.—Phyl'- Since the bodies of insects are soft, one
ane ae can easily see why these conspicuous colors
mimics fresh leaves, 2re of natural advantage. A single stroke
(Holder. ) of the beak of a bird might prove fatal

to any of them. The bird must learn by
experience that the insect is armed or distasteful, but if the
insect is conspicuously colored, it will be noticeable and easily
remembered, so that the bird will not attack another of this
brightly colored kind. Hence the species will be perpetuated
and the characteristic colors handed down to the next genera-
tion, or, in other words, ‘“ preserved and accumulated by natural
selection.”

Alluring or directing colors or forms may be found among in-

1 Kellogg.

—SSs

aes
tees

—

INSECTA 119

sects, according to Poulton. The apical portion of the fore-
wing and the hind portion of the posterior wing are especially
marked with borders or eye-like spots, and are often prolonged,
as in the swallow-tail butterfly, into antenne-like processes or
tails. These, resembling the head with eyes and antenne,
direct the stroke of the enemy to this part. The insect thus
escapes with the loss of the tip or a scrap of the wing, thus saving
its head or its soft body.

b ;

Fig. 92.—a, Monarch butterfly(Ano’sia plerip’ pus), distasteful to birds.
b, Viceroy (Basilar’chia archip’pus), which mimics it. (From Kcllogg’s
‘Zoology,’ Henry Holt & Co., Publishers.)

Mimicry.—The viceroy butterfly (Fig. 92, 6) imitates, uncon-
sciously, of course, the common ‘ monarch” or milkweed
butterfly, since the latter is seldom eaten by birds, owing to a
disagreeable taste or odor. Many bees are mimicked by flies,
and distasteful beetles by other beetles.

Muscular System and Locomotion.—Locomotion may be in
any one or all of three ways—running, jumping, or flying. The

120 BRANCH ARTHROPODA

muscular system varies widely in the different forms. In the
caterpillars there is a ‘simple worm-like arrangement of
segmentally disposed longitudinal and ring muscles,” while in
the more active forms, as flies and bees, the muscular system is
complicated. The muscles are composed of fine, cross-striated
fibers, forming masses of various sizes, and are attached to the
rough inner surface of the exoskelton. The muscles are trans-
parent and have great contractile power.

Digestive System.—The alimentary tube (Fig. 93), which may
be coiled much or little, varies greatly. It is about the length

Fig. 93.—Internal anatomy of Calopte’nus fe’mur-ru'brum: at, Antenna
and nerve leading to it from the “ brain” or supra-esophageal ganglion
(sp); oc, ocelli, anterior and vertical oncs, with ocellar nerves leading to
them from the “ brain”; @, esophagus; ™, mouth; /b, labium or under lip;
if, infra-esophageal ganglion, sending three pairs of nerves to the man-
dibles, maxilla, and labium respectively (not clearly shown in the engrav-
ing); sm, sympathetic or vagus nerve, starting from u ganglion resting
above the esophagus, and connecting with another ganglion (sg) near the
hinder end of the crop; sal, salivary glands (the termination of the salivary
duct not clearly shown by: the engraver); 1v, nervous cord and ganglia;
ov, ovary; ur, urinary tubes (cut off, leaving the stumps); ovt, oviduct;
sb, sebaceous gland; be, bursa copulatrix; ort’, site of opening of the oviduct
(the left. oviduct cut away); 1-10, abdominal segments. All other organs
labeled in full. (Drawn from his original dissections by Mr. Edward
Burgess.) (From Packard’s “ Zoélogy,’’ Henry Holt & Co., Publishers.)

of the body in carnivorous forms, and longer in the herbivorous
insects. It consists of a mouth, esophagus, crop, gizzard (the
chitinous lining of which is toothed for grinding the food), a
digestive stomach, and an intestine. There may be one or two
pairs of salivary glands, and usually two or more pairs of
gastric ceca containing glands supposed to supply digestive
fluids. The intestine usually consists of a small intestine and a
large intestine, the two regions of the latter being the colon and
the rectum. The Malphighian tubules, fine tubes connected
with the intestine at the beginning of the rectum, take the place

“INSECTA 121

of kidneys. There is no liver. The entire viscera are en-
veloped in the “fat body.” The anal opening is in the last
segment of the abdomen.

Insects feed upon the juices, leaves, or even the wood of
plants, or are parasitic or predaceous upon various forms of
insects, and upon other animals as well. Some live upon de-
caying organic matter.

Fig. 94.—Ideal transverse section of an insect: h, Dorsal vessel; 3,
intestine; n, ventral nerve-cord; t,t, stigmata leading into the branched
tracheal tubes; w, w, wings; a, coxa of one leg; b, trochanter; c, femur;
d, tibia; e, tarsus. (After Packard.)

The circulatory organs are extremely primitive in character.
The heart or dorsal vessel extends through the abdomen just
underneath the dorsal surface. It is partially divided by valves
into chambers, the number of which varies. The anterior
chamber extends into or near the head and is sometimes called
the aorta: The heart chambers pulsate rhythmically, from the
posterior one forward, and force the blood out into the body
cavity. There are no veins or arteries, so it flows through the
sinuses or open spaces between the organs, bathing the tissues,
and finally bathing the walls of the alimentary tube, where it

122 BRANCH ARTHROPODA

takes up the food supply and then re-enters the heart through
the side openings. It does not supply the tissues with oxygen,
since it receives only enough for its own use.

Respiration is carried on by a series of air-tubes called
trachee. These tubes are interbranching and penetrate to
every portion of the body. The air enters them through a
pair of stigmata or pores, one on either side of each segment.
The functions of these trachez are to take up oxygen from the
air and to distribute it to the tissues of the body, since this is
not done by the circulation of the blood, and to collect and carry
off the carbon dioxid.

Insects which live in water either come up to the surface to
breathe and, in some cases, to take down a supply of air held
on the outside of the body by a fine pubescence, or they are
provided with tracheal gills which will enable them to breathe
air mixed with water. Gilled insects, of course, do not have to
come to the surface to breathe.

The Nervous System.—Besides the central or ventral (Fig.
93) nervous system (see Branch Arthropoda), insects have
a small and varying sympathetic nervous system (Fig. 93),
consisting of a few small ganglia sending nerves to the automatic-
acting visceral organs. Commissures connect the sympathetic
system with the brain just at the origin of the subesophageal
commissures.

Touch.—The sense of touch is located in the “ hairs” dis-
tributed over the various parts of the body, but most numerous
on the feelers.

Taste is located on small papille or in pits on the mouth-
parts, particularly on the tips of the palpi and on the upper wall
of the mouth.

Smell is probably the most used sense of insects. The
organs of this sense are minute papille and ‘ microscopic pits ”
on the antenne and mouth parts. It has been proved that
most insects find their food by this sense. ‘ It is believed that
ants find their way back to their nests by the sense of smell and
that they can recognize by scent, among hundreds of individuals
taken from various communities, members of their own com-
munity.’’!

’

! Kellogg’s “ American Inscets.”’

INSECTA 123

Hearing.—Many insects have sound-producing organs and
auditory organs; and it has been proved by experiment that they
hear. The ear of the grasshopper or locust, a small tympanic
membrane, is situated at the anterior end of the abdomen, while
that of the katy-did and cricket (Fig. 95) is situated on the tibia
of the fore-leg. There is a special auditory ganglion. The
mosquito has its auditory organs in the antennz in the seg-
ments next to the basal ones, through which the sound or vibra-
tions are carried by many fine auditory hairs, and from which the
auditory nerves lead to the ‘‘brain.”” It is thought that the
male mosquito finds his mate by her song.

Sight.—Insects usually have both simple and compound
eyes, though either kind may be found alone; and a few in-
sects are blind by degeneration. The ocelli, or simple eyes,
are usually three in number and form a little triangle on the

Fig. 95.—The front leg of the cricket enlarged, showing the ear at a.

top of the head. Each of them is supplied with a special nerve
from the “brain.’”’ It is thought that the ocelli can do little
more than distinguish light from darkness and that their range
of vision is restricted to an inch or two in front of the head.
The compound eyes, two in number (see Fig. 84), are usually
large and conspicuous, often composing more than two-thirds
of the entire head. Each compound eye presents from twenty
to several thousand polygonal facets, or windows, which, alto-
gether, form the cornea. It is thought that the range of vision
of the compound eyes is two or three yards. The larger the
eyes, the wider will be the range of vision, while the smaller
and more numerous the facets, the sharper and more distinct
will be the image. Experiment and study of the structure of the
eye, says Kellogg, “indicate that, at best, the sight of insects
cannot be exact or of much range.”

124 BRANCH ARTHROPODA

The psychology of insects is a very interesting study. Whether
the activities of insects are due to reflex action, instinct, or
intelligence can be better determined when studying the various
species, but one will surely find that insects, as well as being the
most numerous and various, are also the most interesting and
wonderful of all the classes of invertebrates.

Multiplication is by eggs, of which many are deposited in
various places. Some are placed on or in another animal’s
body, others on leaves or stems of plants, which serve as food
for the young. However, some insects, as the Aphides, show
parthenogenesis, 1. e., they are supposed to produce young
from unfertilized eggs.

Metamorphosis.—Insects pass through a more or less com-
plete series of changes, called metamorphosis. The larve,
whose business it is to feed and grow, are called by various names,
as caterpillars, grubs, nymphs, and maggots. Since the larve
are wingless they are placed in different relations to their
environment from those of the adult, and hence often have
special larval organs. The larval stage is followed by a quiet
stage called the pupa (Fig. 89). In this condition many in-
sects pass the winter and come forth in the spring as adults
or imagoes, the reproductive stage. Others remain in the
pupa stage but a few wecks, thus giving time for two or more
broods in a season.

Parasitism is common in insects. Parasites may be ex-
ternal or internal. The natural consequence of a parasitic life
is degeneration, as is seen in lice and fleas, whose ancestors were
winged insects.

Environmental Influences.—Insects are affected hy tempera-
ture. They become active with the rise of temperature in the
spring, and some become dormant or hibernate as the tempera-
ture declines in fall and carly winter. Most of them die with
the advent of frost. The direction and velocity of the wind
is a factor in insect life, expecially in its distribution.

The amount of precipitation will mfluence the amount
and kind of vegetation, which determines to a large extent the
number and kind of inseets. Certain kinds of precipitation,
as hail, for example, or floods, would destroy large numbers of
insects. Any environmental factor would increase or decrease

INSECTA 125

the activity, food, enemies, dispersal, migration, mentality, or
other phenomena connected with animal life.

Geologic Distribution.—Insects of some kind have existed
for a long time geologically, insect remains being found in the
lower and upper Silurian.

Economic Importance.—Insects devour our crops, carry dis-
ease, annoy us when awake and prey upon us when we sleep,
injure or destroy our stock, infest our orchards, and in some
countries the white ants do much damage to dwellings. The
damage to our American crops has been estimated at the enor-
mous sum of $700,000,000 in one year. But when we remember
that insects are also dangerous
to health and life, how much
more is the number of injuri-
ous insects to be deprecated.
Kellogg says, ‘‘ Mosquitos help
to propagate and are almost
certainly the exclusive dis-
seminating agents of malaria,
yellow fever,” and other dis-
eases; ‘‘house-flies aid in
spreading typhoid fever and
other diseases; fleas are agents
in distributing the germs of ; hs
the bubonie plague.” Howard JHE. 06-_ rete My, whieh cans
says the germs of the disease larged. (L. 0. Howard.)
known as “‘ pink-eye ”’ are car-
ried by very minute flies of the genus Hippelates. Other insects
are known to spread other diseases (Fig. 96).

However, some insects are valuable to man. The honey-bee
makes honey; other insects furnish galls for ink; others, dye-
stuffs, such as cochineal; while others serve as scavengers,
and the silkworm (Fig. 97) furnishes our finest clothes. The
bumble-bee fertilizes the clover blossoms, other insects cross-
fertilize the flowers of many plants, and many serve as food for
birds. Thus, while some insects are very harmful to us, others
are very valuable to us. If we (with the help of the birds)
exterminate those which are injurious and protect those which

a

126 BRANCH ARTHROPODA

are beneficial, our crops will be the larger and more profitable,
and our bodies more secure from disease.

Classification —Entomologists vary in their opinions as to
the number of orders into which the Class Insecta should be
divided. Packard’s ‘‘ Guide” (1883) gives eight orders, while
Comstock’s ‘‘ Manual” (1895) and Kellogg’s “American Insects”
(1905) each give nineteen orders. Kellogg says, “‘ In the first
place the author believes that this classification! best represents
our present knowledge of insect taxonomy; in the second place,

5 6 Y ¥ F - WM 12
! i H Popo og
!

} : . tog
H : H ae
‘

Fig. 97.—Adult silkworm: 1, Head; 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, rings;
11, horn; 13, three pairs of articulated legs; 14, four pairs of abdominal
or false legs; 15, a pair of false legs on the last ring. (Farmers’ Bull.
165, U.S. Dept. of Agriculture.)

this is the classification taught by nearly all the teachers of
entomology in America.”

Students wishing to study insects in detail should consult
either Comstock’s or Kellogg’s large work on insects.

ORDER I. AP’TERA OR THYSANU/RA

These are small or minute wingless insects which undergo
no metamorphosis. The body is covered with hairs or scales.
There are several pairs of rudimentary abdominal appendages,
probably vestiges of abdominal legs in ancestors. The mouth
parts are adapted for biting. ‘‘ Their internal systems of organs
have a segmental charactcr corresponding to the external scg-
mentation of the body.’* They live in sugar boxes and pan-

1 Comstock’s classification, * Kellogg, p. 59.

EPHEMERIDA 127

tries or under leaves, and in the spring they are sometimes
found in large numbers on the surface of pools of water or upon
the snow.

_ Campo'dea staphyli'nus, which is regarded as the most primitive living
insect, belongs to this order. It is about } inch long, white, wingless,
and flat. Its body is exceedingly

soft and delicate. It is widely dis- a

tributed. ; A
The ‘‘fish-moth” (Lepis’ma sac- ee

chari'na) of the house (Fig. 98), which oy
is neither a moth nor a fish, is sil- \ ¥
very white, with a yellowish tinge
on antenne and legs. It isabout 3
inch long, has three long caudal ap-
pendages, and feeds chiefly upon
sweet starchy materials, often at-
tacking starched clothing and the
paste of wall-paper and book-bind-
ings. It may be gotten rid of by
sprinkling fresh pyrethrum powder
in the places infested or by spraying
slightly with nicotin or formalin.
The ‘‘spring-tails” (Collem’bola)
have a forked spring attached to the
next to the last segment of the ab-
domen, by means of which they leap
from a few inches to a foot in the air.
The ‘ snow-fleas”’ collect in large
numbers on the snow in spring. {
They are often a cause of great an- cE
noyance where maple sugar is made. |

—e

Surely the insects of this Fig. 98.—Lepis’ma sacchari’na,
order, by their simplicity of Dore ee is,
structure and their similarity
of somites, show their worm ancestry, though some species
show much more complexity of structure. It will be interest-
ing for the student to consider how, from such a generalized
primitive form as Campodea staphylinus, nature can produce,
by modification of parts, an insect of highly complex structure.

ORDER II. EPHEMER’IDA

The May-flies, in the adult form, are insects of a day, but
they pass two or three years in the larval stage. When they
emerge from their larval condition into their winged form

128 BRANCH ARTHROPODA

they come forth in myriads along streams. The authors saw
their dead bodies piled a foot deep on an Illinois river bridge
just under the electric lights. So thick were they that workmen
came next day and shovelled myriads of them into the river.
They are fragile, soft skinned, and long bodied, with four gauzy
wings, of which the anterior pair is much the larger. The
abdomen ends in long thread-like anal projections. The
mouth parts are rudimentary. Indeed, the adults are said to
take no food, but to reproduce and dic. The eggs are laid in
the water. Soon appear tiny, soft-bodied, wingless nymphs,
bearing leaf-like fringed gills arranged segmentally along the
sides, and two or three many jointed anal appendages. They
have strong legs and can both swim and walk. They lie on the
bottom of streams, and, with their powerful mandibles which are
adapted for biting and chewing, catch and devour other insects.
They eat plants also, and are themsclves prized as food by many
kinds of fishes and other aquatic animals.

After the ninth molt (some species have twenty-one) the wing-
pads begin to develop. The nymph continues to grow and to
molt, until finally it leaves behind its ‘ water-nymph skin ”’
and comes forth a winged May-fly. Again it sheds its skin,
it may be within a few minutes or within twenty-four hours, a
thin layer coming off even from the wings. This is the only
known instance of an insect molting after acquiring its wings.

ORDER III. PLECOP’TERA

The stone-flies are comprised of a single family, the Per‘lide.
These grayish or brownish insects (Fig. 99) are 3 to 12 inches
long and have four large membranous wings, but the posterior
pair folds up like a fan when not in use. Unlike the dragon-
flies, in which the anterior and posterior wings are about equal
in size, the posterior wings are much wider than the anterior
ones. The mouth parts are adapted for biting, but poorly so
as compared with those of the dragon-fly. The adults probably
eat little. The long antennee are many jointed and the abdomen
is often furnished with a pair of many jointed bristles or fila-
ments. The 5000 or 6000 eggs are probably well scattered in
the swift current before dropping to the bottom. The meta-

ODONATA 129

morphosis is incomplete. The nymphs, like those of the
dragon-fly, are aquatic. They are provided with gills. Those
who advocate the aquatic ancestry of insects believe that the
spiracles are the openings left when the gills were lost, but certain
species of stone-flies retain their gills—though shrivelled and
probably functionless—and have wholly independent spiracles.

A B
Fig. 99.—A, Stone-fly. B, A nymph of a stone-fly. (Comstock.)

The larve of stone-flies are flat and cling closely to the surface
of stones in the swiftest portion of the stream. They cannot
live in stagnant or foul water. Their resemblance to a fossil
is almost perfect. This resemblance is their protection from
their enemies, the fishes. These larval stone-flies are good bait
for trout.

ORDER IV. ODON’ATA

Dragon-flies.—To this order again belongs’ a single family,’
the Libellu'lide, or dragon-flies (Fig. 100). They have many
common names, as ‘“ mule-killers,’” ‘‘ snake-doctors,’’ and
“ devil’s darning-needles,”’ but, in spite of these terrifying names,
they are all perfectly harmless to man.

' Kellogg, p. 72.

2 Kellogg includes the damsel flies.
3 Comstock, p. 90.

130 BRANCH ARTHROPODA

The four finely netted membranous wings of the adult dragon-
fly are long, narrow, strong, and nearly equal. If unequal, the
posterior wings are the larger. Each wing has a joint-like struc-
ture near the middle of the front margin. Their mouth parts

Fig. 100.—Dragon-flies in the farval, pupal, and imago. state.
(After Tenney.)

are adapted for biting. Their compound eyes are very large
and the antenne short. The metamorphosis is incomplete.
The eggs are laid in water or attached to aquatic plants.
They soon hatch, and the larve (Fig. 100), called nymphs,
live a predatory existence. They lic in wait for their prey.

ISOPTERA 131

“The fierce face of the young dragon is all concealed ” by its
extensible lower lip, which folds up. With their strong jaws and
legs dragon-flies secure and devour their prey. They devour vast
numbers of larval mosquitos and are thus of great use to man.
Finally, the full-grown nymph creeps up some stem, and the
winged form of the imago or adult dragon-fly breaks through the
old skin and flies away into the air and sunshine to enjoy its
aérial life until the falling temperature ends its existence.
These beautiful creatures may be called creatures of the air, for
they actually feed upon the wing and may sometimes be seen
poised in mid-air as if resting. The adult devours many gnats
and mosquitos. There are two types of dragon-flies, one
which keeps its wings horizontal and one which folds its wings
together vertically over the back.!

The breathing of the nymphs is peculiar. “The caudal end
of the alimentary canal is lined with trachex, and water is
alternately drawn into and expelled from this cavity. The
water may be expelled with such force as to propel the body
forward. So this has a locomotive function also.”

ORDER V. ISOP’TERA

The Termites (Fig. 101), or so-called ‘‘ white ants,” are abun-
dant in the tropics, but less so in the United States. Where
they are numerous they become pests, destroying houses, furni-
ture, or anything made of wood. They are not ants, as may be
seen by their structure.

The body is always soft and usually whitish in color, though
sometimes brown. ‘It is plump and slightly broader than
thick.” In the union of the abdomen with the thorax the little
pedicel or stem found in the ant is lacking, the abdomen being
broad at the base. They are blind or have simple eyes. They
conceal themselves from the light. The slender antenne look
like strings of tiny beads.

The young are all apparently alike when hatched, but by
some means not understood they are afterward developed into
soldiers, workers, males (kings), and females (queens). The
winged males and females swarm, and each pair which is fortu-

1 Damsel flies, Kellogg.

132 BRANCH ARTHROPODA

nate enough to escape being eaten by birds finds a place for a nest,
or is taken possession of by workers, and a new colony is founded.
The males and females lose or divest themselves of their wings.

Termites usually feed upon rotten wood, but some specics
attack soft plants and live wood, or cven cloth, paper, and leather.
In Africa these insects sometimes build pyramidal nests twenty
feet high and form villages of them. They are so numerous

Fig. 101.—White ant (Termes flavipes): a, Larva; b, winged male; ce,
worker; d, soldier; e, queen; f, pupa. (Riley.)

and bold that “nothing can defy the marauders but tin or
iron.”? Many species of insects have been found living a com-
mensal life with termites, ‘a sort of inscet economy termed
termitophily.”’

ORDER VI. ORTHOP’TERA

This order comprises some of our most familiar insects, as
the cockroaches, mantids, leaf-inseets, walking sticks, short-
horned grasshoppers (locusts), long-horned grasshoppers, and
crickets.

The Orthoptera usually have two pairs of wings. The
anterior wings are thicker and overlap or cover the posterior
wings when the insect is at rest. The walking-stick is wingless.

1 Drummond.

ORTHOPTERA 133

The grasshopper (see Fig. 85, p. 113) may be taken as typical of
this order.

The Head.—The mouth parts consist of a labrum or upper
lip, the mandibles, a pair of crushing or biting jaws, followed
by a pair of mazille, or smaller jaws, each of which consists of
three parts—an outer, jointed maxillary palpus, and a spoon-
shaped piece which covers the brown incurved maxilla. Then
follows the labium, or lower lip, with its jointed labial palpt.
On the head are two compound eyes and three simple eyes,
or ocelli, and a pair of antenne or feelers.

The thorax is divided into three well-marked divisions:
First, is the movable, cape-like prothoraz, to which is attached
the first pair of legs. Second, is the mesothoraz, bearing the next
pair of legs and the anterior pair of wings, which are straight
and rather narrow. Third, is the metathoraz, with the large
third pair of legs and the posterior wings, which fold up like a
fan under the anterior wings when not in use.

The segmented abdomen follows the thorax. Close observa-

tion with the magnifying glass will show minute openings on the
sides of the segments. These openings are the spiracles or
breathing pores.
’ “ Singing.”—This order of insects gives us most of our
“smgers”’ and leapers of the insect world, and, strangely enough,
the leapers are the singers, and, stranger still, they sing without
a voice. Of the six families of Orthoptera, three are composed
of these leaping and “ singing ”’ insects. The locust or short-
horned grasshopper, when at rest, makes a noise by rasping the
inner surface of the hind thighs across the thickened and ridged
longitudinal vein of the outer surface of the fore wings. In the
air, the “clacking”’ is made by rubbing the upper surface of the
anterior margin of the hind wings back and forth past the
under surface of the posterior margin of the fore wings. ‘ This
can be heard for a distance of several rods.’”!

The male cricket holds his fore wings (Fig. 102) up over his
body and rubs together the upper side of their basal region.
The male tree crickets, katy-dids, meadow-green grasshoppers
with long antennz, also rub together specially modified por-
tions of the fore wings.

! Kellogg, p. 134.

134 BRANCH ARTHROPODA
Hearing.—The “ears” consist of a pair of small tympanic
membranes, situated on the basal segment of the abdomen in
the locust and on the tibie of the forelegs (Fig. 95, p. 123)
; of the cricket and katy-did. Associated
with each tympanum is a vesicle filled
with liquid and an auditory ganglion, which
is connected by a nerve with one of the
thoracic ganglia.
Feeding —All Orthoptera have biting
mouth parts, and bite off and chew their
food. Most of them are vegetable feeders,
but the mantis is carnivorous. The locusts
or grasshoppers have at times wrought
great havoc with man’s crops, as both
; Fig, 102 Wing sacred and secular history tell us.
Oh Cueshe Tsien Leaping.—In the leaping Orthoptera the
ee ee is posterior pair of legs is especially adapted
scraper at b. for this purpose. They are large and long,
and when walking the knee-joints are much
higher than the insect, thus giving leverage for their prodigious
leaps, in which they rival the fleas in their athletic records.
The metamorphosis is incomplete, the young (nymphs)
(Fig. 103) differing from the parents in size and absence of wings
(Fig. 104).

Fig. 103.—Calopt’enus spre’tus: a,a, Newly hatched larvx; b, full-grown
larva; c, pupa, mated size. (After Riley.)

The cockroaches (Blat’tide) are nocturnal insects, found about the
pantries and water-pipes of our dwellings, though in the North, according
to Comstock, our native species lives in woods and fields. One may often
find them hiding under bark, sticks, and stones. The jaws are strong and
toothed, and they are greedy little ‘ereatures, devouring : anything they can
get,‘ eating book-bindings and bed-bugs with equal ala acrity.”” The body
is flat and slippery and the legs are adapted for rapid running, enabling

ORTHOPTERA 135

them to escape readily into cracks and crevices. Cockroaches were the
dominant insects in carboniferous times. There are four common species,

Fig. 104.—Calopt'enus spre'tus. Process of acquiring wings: a, Pupa
with skin just split on the back; b, the imago extending; c, the imago nearly
out; d, the imago with wings expanded; e, the imago with all parts perfect,
natural size. (After Riley.)

Fig. 105.—African mantis or soothsayer, with its egg-mass. (Monteiro.)

only one being native to the United States. The eggs are laid in small,
bean-shaped, horny, brown cases. The young are precocial. Cock-

136 BRANCH ARTHROPODA

roaches may be gotten rid of by dusting fresh insect-powder into the
cracks of pantry and kitchen with a little hand-bellows. :

The praying mantids (Man’tide) (Fig. 105) are peculiar insects which get
their name from the attitude in which they watch for their prey. They
stand motionless with the head raised upon the long prothorax and the
front legs clasped in front of the face. These front legs are spiny and are
used only for seizing and holding their prey. The wings are usually leaf-
like in color and texture, and this special protective resemblance is very
good when the insect rests upon a plant. ‘They are carnivorous and do

F

|

!
Fig. 106.—A walking-stick among the stems of a flower-cluster. (From
life.)

much good in destroying insect pests, so much indeed that Professor Slinger-
land is trying to establish and distribute a European species in the United
States. Most of the mantids—less than a score of specics—are tropical.
Our most common native species, Phasmomn’ts caroli’na, is about 2}
inches long. They are everywhere regarded with strange superstition,
and the superstitious say one should ‘never kill a mantis, as it bears
charm against evil.’ A Japanese mantis (Tinode'ra sinen’sis), recently
introduced into the United States, is brown. This protection conceals
the insect not only from its enemies, but from its prey, for which it ‘‘ lies

ORTHOPTERA 137

in wait,’ and may thus be called aggressive resemblance. Several species
from India resemble flowers, and thus attract insects, upon which they
feed. This is an example of alluring colors.

The walking-sticks (Phas’midw) (Vig. 106) afford even better examples
of special protective resemblance than the mantids. Our species are
wingless and may be either green or brown, and are usually found upon
twigs of a color corresponding to that of their bodies. The body, which
is long, straight, and slender, looks exactly like a twig, while the slender
legs look like so many tiny branches. One may pick up a walking-stick,
thinking it a twig until it moves. Although it is so repulsive to the unin-
itiated, it is a perfectly harmless creature. The only common species in the
northern states, Diapherom’era femora’ta, ‘‘ feeds upon the leaves of oaks
and other trees. It drops its hundred seed-
like eggs loosely and singly on the ground,
where they lie through the winter, hatching
irregularly through the following summer,”?!
or even the second summer. Over six hun-
dred species of this family are known. They
are numerous in the tropical and sub-tropical
countries and present many striking resem-
blances to their environment, one of the most
perfect of which is the “ green-leaf insect”
(Fig. 90, p. 117). Its wings, flat body, ex-
panded legs, and even head and prothorax
are bright green flecked with yellow, making
it look wonderfully like a leaf attacked by
fungi.

‘The locusts or short-horned grasshoppers
(Acrid'ide) include those ‘grasshoppers’ in
which the antenne are shorter than the body,
and in which the ovipositor of the female is
short and made up of four separate plates.’’?
The tarsi have three joints. The first ab-
dominal segment has a tympanic membrane i
on each side. It is to this family that the ; ‘ ‘
locusts mentioned in the Bible and in his- Fig. 107—Carolina lo-
tory belong, as well as those which have cust killed by a fungus.
wrought such havoc in our own country. (Bulletin No. 81, New
A conspicuous species is the common red- Hampshire Experiment
legged locust, Melan’oplus fe'mur-ru'brum. Station Insect Record,
There are about five hundred species of this 1900.)
family in the United States, but only three or
four of them are migratory. These go in swarms, sometimes so dense
as to obscure the sun as a great cloud, and when they alight they literally
devour every green thing in that region. The largest, most injurious, and
most numerous of these are the Rocky Mountain locusts (Melan’oplus
spre‘tus). Their permanent breeding-grounds are uponthe western pla-
teaus, from 2000 to 10,000 feet above sea level, and they cannot endure
for successive generations the low, moist land of the Mississippi Valley.
“These locusts show a tendency to become gregarious from the beginning
of their life as nymphs. A recent method of fighting them is to cultivate

' Kellogg.
2 Comstock.

138 BRANCH ARTHROPODA

in a sweet solution a destructive fungous growth (Fig. 107). A few members
of the swarm are dipped in the solution and turned loose, spreading the
disease! Melan’oplus atlan’tis sometimes does much harm in New England.

Locusts lay their eggs, numbering from 25 to 125, in oval masses, cov-
ered with a glutinous substance. The female deposits them (Fig. 108) in
the ground or in rotten wood, with her strong, horny ovipositor, or they
may be laid on the surface of the ground among the grass and weeds. The
eggs are usually laid in the fall and hatch in the spring, there being but the
one new brood a vear. The young resemble the parents in general, having
biting mouth parts and long legs. They are paler and wingless. The
wings appear as minute scale-like projections and grow larger with each of
the five or six molts (ig. 104) Strangely enough, the hind wings, which
are always underneath the fore wings in the adult, lie outside during devel-
opment. Birds are the best exterminator. The eggs may be plowed up

Fig. 108.—Rocky Mountain locust: a, a, a, Female in different positions,
ovipositing; b, egg-pod extracted from ground, with the end broken open;
c, a few eggs lying loose on the ground; d, ¢, show the earth partially removed
to illustrate an egg-mass already in place and one being placed; f, shows
where such a mass has been covered up. (After Riley.)

in the fall, or when they hatch in the spring the young could be crushed by
heavy rollers or burned by seat tering straw over the ground and lighting it?

Locis’tide.—This family includes crickets, katy-dids, and long-horned
grasshoppers. Unfortunately, the common name of locust is applied only
to members of the family of Acridida, and to the cicada of the order
Hemiptera, but. to none of the Locustide. The long-horned meadow-green
grasshopper has the delicate antenne longer than the body, the tarsi
four jointed, the ovipositor sword shaped, and the tympanum on the
tibia (ig. 95, p. 123) of the front leg. The males call their mates by

'Linville-Inelly, p. 15.
2 Kellogg, p. 139.

ORTHOPTERA 139

rubbing together the specially modified wing covers. These grasshoppers
abound in our meadows everywhere. If you would know how perfect is
their protective resemblance, try to find one which you have seen on the
wing, after it has alighted. Some species found in caves are wingless,
saa aaa and blind. Their antenne and hind legs are developed to a great
ength.

The katy-dids, of which there are several genera, are rather large, usually
green insects. They live upon trees and shrubs, feeding upon foliage and
tender branches, though they sometimes eat animal food. Only the males
tell us ‘ Katy did” or ‘‘ she didn’t.”” They usually “ sing ”’ at night from
July or August until frost. They are not gregarious. Their thin, finely
veined wings are almost indistinguishable in the foliage.

Closely allied to the katy-dids, but looking more like crickets, are the
wingless grasshoppers, the cricket-like grasshoppers, and shield-backed

Fig. 109.—Mole cricket (Gryllotal’pa boria‘lis). (Burmeister.)

grasshoppers. They are dull colored and live under stones and rubbish
or loose soil.

The crickets, of which there are few species, have the wing covers flat
and overlapping*above, and bent sharply down at the edge of the body like
a box cover. The antenne are long and the ovipositor is spear shaped.
They include the mole crickets, true crickets, and tree crickets.

Mole crickets (Fig. 109) are fitted for a burrowing life. The front tibie
are broadened and shaped somewhat like the feet of a mole. They feed
upon the tender roots of plants, and sometimes injure potatoes (Fig. 110).

The true crickets, our familiar black species, live in houses or fields.
They usually feed upon plants, but some are predaceous. The eggs, laid
in the fall, usually in the ground, hatch in summer. Only a few of the
old crickets survive the winter.

140 BRANCH ARTHROPODA

The tree crickels live in trees or on tall plants. The female ‘ snowy
tree cricket ”’ does much damage by laying her eggs in grapevines or rasp-

Fig. 110.—Potato injured by mole cricket.

berry canes, causing them to die above the puncture. These canes should
be cut and burned in winter or early spring before the eggs hatch.

ORDER VII. HEMIPTERA

This order contains some of our most common and destruc-
tive insects, as the chinch-bug, the grape phyllox’era, the San
José scale, the bed-bug (Fig. 111), the louse, the squash bug,
stink-bugs of various kinds, plant-lice (A phid’id@), and bark-lice
(Coc’cide), which furnish «lye-stuffs, as cochineal, stick-lac, from
which we get shellac, and China wax.

The Hemip’tera include some five thousand species in North
America. All of these species agree in that the mouth parts
are modified into a piercing and sucking beak. Their food, con-
sequently, is the blood of men or of other animals or the juices

HEMIPTERA J41

of plants. The sucking beak consists of the labiwn, which, to-
gether with the labial palpi, is modified into a jointed sheath.
This incloses the mandibles and maxille, which are changed
into long, piercing stylets.!. The labrum or upper lip is small or
rudimentary. There are usually four wings. In the typical
Hemiptera, as exemplified in the sub-order Heterdp'tera, the
character of the anterior wings is a distinguishing feature.
The basal portions of these wings are thickened and parch-
ment-like, while the terminal portions are membranous and
overlap when the wings are folded over the back. From the
character of these wings the order gets its name—hemit, half,

"Fig. 111.—Bed-bug (Ct’mez lectular'ius): a, Adult female gorged with
blood; 6, same from below; c, rudimentary wing-pad; d, mouth parts.
All enlarged. (Marlatt, Bull. U.S. Dept. of Agriculture, 1896.)

and pteron, a wing, 2. e., the Hemip’tera or “ half-winged ”
insect. The second pair of wings are membranous and fold un-
der the fore wings when not in use. The electric-light bugs,
bed-bugs, water-bugs, and squash-bugs are familiar examples.
In the sub-order Homop’tera the anterior wings are not thick-
ened, but are of the same structure throughout, as in the cicada.
In the sub-order Parasi’ta are found wingless parasitic hemip-
tera which prey upon certain mammals, for example, the head
and body lice of man, dogs, cattle, hogs, sheep, mice, and
rabbits.
1 See Kellogg, p. 164.

142 BRANCH ARTHROPODA

The giant water-bugs (Belostom’ide) are an example of the largest
Heteroplera or true bugs. They are often seen about electric lights. They
fly from pond to pond and are very rapacious, feeding upon the juices of
young fishes, insects, and tadpoles. ade,

The chinch-bug family (Lyge’/w) has nearly two hundred species in the
United States. The most destructive is the small but widely distributed
chinch-bug (Blis’sus leucop’terus) (Fig. 112), and though it measures less
than } inch in length, it costs the United States $20,000,000 annually, for
it is “ the worst pest of corn and one of the worst of wheat.” There are two
generations of the chinch-bug annually. The adults winter under rubbish,
and in early spring they lay their eggs in fields of grain upon roots or stems
beneath the soil. They hatch in about two weeks, and the little red nymphs
attack the root and then the stalk of the wheat. They mature in about
six or seven weeks, when they are “ blackish, with the wings semitransparent
white, and with a conspicuous small triangular black dot near the middle
of their outer margin.” At about harvest time they migrate by the

fk:

Fig. 112.—The chinch-bug (Blis’sus leucop'terus): a, b, Eggs; c, newly
hatched larva; d, its tarsus; e, larva after first molt; f, same after second
molt; g, pupa—the natural sizes indicated at sides; h, enlarged leg of per-

fect bug; j, tarsus of same still more enlarged; i, proboscis or beak, en-
larged. (Riley.)

millions to fields of growing corn, marching in a body like an approaching
army. When the bugs of the first brood have reached maturity, they pair,
at which time only they use the wings, and the second generation is begun.
The adults of the second generation that survive the winter lay the eggs
pee spring brood. It is thought that a third brood sometimes appears
in Kansas.

Their migration from wheat to corn fields may be hindered by plowing
furrows around the ficlds and pouring crude petroleum or coal-tar into these
moats. If this has not been done, when the bugs collect on the first few
rows of corn they should be sprayed at onee with kerosene emulsion.
Predaceous insects, as the aphis-lion and ladybird beetles, and birds hold
them in check. But a parasitic fungus (Nporotri/chum globulif’erum)
will kill (he bugs rapidly in moist, warm weather.

The cicadas (Ciead’id@) are easy of recognition on account of their
large, blunt-headed, robust bodies, the three oeclli, and their shrill “ sing-
ing’ during the daytime in the late summer and early fall. The male
does all the talking or singing, if you choose to call it a song, and ‘ his wife

HEMIPTERA 143

cannot talk back.”’ The sound is made by “ stretching and relaxing a pair
of corrugated tympana or parchment-like membranes by means of a
muscle attached to the center of each.’’!

The strangest freak in all insect life is the periodical cicada or seventeen-
year locust (Fig. 113). It is the longest lived of all insects, for while
other insects pass from the egg to imago form in a few days or weeks, or, at
the most, in one to three years, this insect requires from thirteen to seven-
teen years for this development. In the spring the female cuts slits in
tender twigs and lays her eggs therein. In about six weeks they hatch
and the nymphs spend the required seventeen years, or, in the case of a
southern form, thirteen years, in the ground. Thcy feed by sucking the
juices of tender roots. In the spring of the seventeenth or the thirteenth
year—as the case may be—they crawl up to the surface of the ground,

Fig. 113.—The seventeen-year Cicada (c) and pupa (a, 6); d, position of
eggs (e); f, larva. (Riley.)

undergo their last molting, and emerge as clear-winged cicadas. This
insect is a fine example of protective resemblance. One may be within
a few inches of a ‘“‘ singing ”’ cicada and not be able to see it, so near the
color of the tree trunk or ground is it. The adult life is short. They lay
their eggs, sing their songs, and die.

The plant-lice or aphids (Aphid’id@) are among our most common and
destructive pests in the green-house, field, ard orchard. There are many
species, most of which are small, the largest barely reaching the length of
4 inch. The small, soft, usually green body is somewhat pear shaped.
Wingless forms are most numerous, but there are forms in almost every
brood which have two pairs of delicate transparent wings, the anterior
pair of which is the larger. ‘‘ The two wings of each side are usually con-

1 Kellogg, p. 167.

144 BRANCH ARTHROPODA

nected with a compound hooklet.”! The sucking beak is three jointed
and may or may not be longer than the body. They have prominent com-
pound eyes and usually ocelli. The long antenn are from three to seven
jointed. Many species have on the sixth segment of the abdomen two
tubular processes, long supposed to be the honey tubes, but Kellogg says
“from them issues another secretion, not sweetish, about which little is
known,” and that the ‘“ honey-dew”’ so relished by ants (p. 179) ‘‘is
now known to be an excretion from the intestine issuing in fine droplets
or even spray from the anal opening.’”’ It is sometimes produced in large
quantities, so that the leaves below the plant lice are coated with it and the
walks beneath the trees spotted by it. It is fed upon by bees and wasps
as well as by ants. In addition to the ‘‘ honey-dew,”’ many species secrete
another fluid, which is excreted as a liquid through * various small open-
ings scattered over the body.” This liquid soon hardens into a wax.
The total waxy secretion appears as a mass of felted threads or wool, as in
the wooly apple aphis, and probably serves as a protection for the soft,
defenseless body.

The aphids are remarkably variable as regards their reproduction sexually
or agamically,? and as regards their possession of wings, so that the life-
history varies not only in different specics, but in the same species under
different conditions. The eggs are laid in the fall, and from them hatches,
in early spring, a colony of wingless individuals which may produce (without
pairing) either living young or eggs. | This may continue under favorable
food supply and temperature for a number of generations. Slingerland,
of Cornell University, reared four generations of wingless ‘ agamic ”’
aphids. At any time, especially if food becomes scarce or other conditions
unfavorable, winged individuals are likely to appear and fly away to other
host plants, where they produce, agamically, new colonies. If temperature
becomes low or other unfavorable conditions occur, these asexual individuals
produce a brood consisting of both males and females. ‘‘ The males may
be either winged or wingless, but the females are always wingless.’’ These
sexual forms pair and produce one or more large fertilized eggs which lies
dormant over winter and hatches into a wingless ‘* stem-mother”’ in the
spring, and a scries of agamic gencrations follow. The multiplication of
aphids is so rapid that, were it not for predaceous insects, such as lady-
bird beetles, aphis-lions, and parasitic Hymenop’tera, and for inseet-loving
birds (see Birds), they would utterly destroy their host plant and ulti-
mately starve themselves. Professor Forbes made an estimate of the rate
of increase of the ‘* corn-louse,’’ and found that if * all the plant-lice de-
scending from a single ‘ stem-mother ’ were to live and reproduce through-
out the year we should have coming from the egg the following spring
9,500,000,000,000 young. As each plant-louse measures about 1.4 mm.
in length and 0.93 mm. in width, an casy calculation shows that. these
possible descendants of a single female would, if closely placed end to end,
form a procession 7,850,000 miles in length.”

Aphids vary greatly in their feeding habits, many feeding upon the
juices of tender leaves, stems, leaf-buds, or blossom-buds, while others
suck the juices of tender roots in the soil, and sometimes the same species
lives both above and below ground. Above ground they may be fought
by strong solutions of soap, by kerosene emulsion, or by a weak solution of
nicotin, Since they suck the juices of plants they cannot be affected by
poisoning the food. Underground, carbon bisulphid is sometimes used,

' Comstock. 2 Glossary.

HEMIPTERA 145

but about the best remedy is to destroy the infested tree or vine, and plant
one of another species which is not a host-plant for the pest.

Fig. 114.—Phylloze'ra vasta'trix: a, Leaf with galls; b, section of gall
showing mother louse at center with young clustered about; c, egg; d,
larva; e, adult female; f, same from side. (a, Natural size; te -f, much
enlarged). (Marlatt.)

Fig. 115.—Phylloze'ra vasta'triz: a, Root- galls; b, enlargement of same, show-
ing disposition of lice; c, root- gall louse, much enlarged. (Marlatt.)

The grape Phylléxe’ra (Fig. 114) is a native aphid found upon the wild
grapevines of the eastern United States. It was introduced into the
south of France before 1863 upon rooted vines sent from America, and,

10

146 BRANCH ARTHROPODA

curiously cnough, says Kellogg, ‘came to California—in which state it has
done much more damage than elsewhere in our country—from France, in-
troduced upon imported cuttings or roots” (Fig. 115). | Probably not less
than 30,000 acres of vineyards have been destruyed by it since it was first
noticed in 1874. “The Phylloxcra appears in four forms: (1) the gall
form, living in little galls on the leaves (Fig. 114), and capable of very
rapid multiplication (this form rarely appears in California); (2) the root
form (Fig. 115), which is derived from individuals which migrate from
the leaves to the roots, and which by the piercing of the roots, sucking the
sap, and producing little quickly decaying tubercles on the rootlets, does
the serious injury; (3) the winged form (Tig. 116), which flies to new vines
and vineyards and starts new colonies; and, finally, (4) the sexual forms,

Fig. 116.—Phyllore’ra vasta'trix: a, Migrating stage, winged adult; },
pupa of same; c, mouth parts with thread-like sucking scta removed from
sheath; d and e, eggs showing characteristic sculpturing; all enlarged
(Marlatt.)

male and female (Tig. 117), which are the regenerating individuals, ap-
pearing after several agamic generations have been produced.” The gall
stage may be omitted, and the individuals hatched from the fertilized eggs
go directly to the roots. The gall form can be prevented by spraying to
kill the winter eggs. But about the only real cure for the infested roots is
to dig them up and burn them and plant out resistant vines. The wild
vines of the Mississippi Valley have evolved with the Phylloxera, and are
capable of living and growing in spite of the pests. The French vine-
yards, as well as those of California, are being renewed by grafting French
stocks upon the resistant roots, thus rendering the vines practically im-
mune. There are many species of aphids, but this example must suffice for
our present. work.

Scale-bugs, mealy-bugs, and others (Coc’cid@) compose a very anomalous

HEMIPTERA 147

group, the species differing greatly in appearance, habits, and metamor-
phoses from those of the most closcly allied familics, and even the two sexes

Fig. 117.—Phyllore’ra vasta'trix: a, Sexed stage larviforni female, the
dark-colored area indicating the single egg; b, egg, showing the indistinct
hexagonal sculpturing; c, shriveled female aftcr oviposition; d, foot of
same; e, rudimentary and functionless mouth parts. (Marlatt.)

Fig. 118.—Ladybird feeding on scale insects, Pentil'ia (Smilia) misel’la:
a, beetle; b, larva; c, pupa; d, blossom end of pear, showing scales with
larve and pupe of Pentilia feeding on them, and pup of Pentilia attached
within the calyx; all enlarged. (Howard and Marlatt, Bull. U. 8. Dept.
of Agriculture.) %

of the same species, says Comstock, differ greatly. The males, unlike all
other members of the order, undergo a complete metamorphosis. The adult

148 BRANCH ARTHROPODA

male has but a single pair of wings and has no organs for procuring food.
The mouth parts disappear during metamorphosis and a second pair of
eyes develops. The adult female is always wingless and the body is always
scale-like or gall-like in form, or grub-like and clothed with wax. Those
of some species retain their eyes, antennx, and legs, while others are fixed
in adult life and very degenerate, lacking eyes, antennw, wings, and legs.
In speaking of the San José scale, Kellogg says, “it has a long, fine, flexible
process projecting from near the center of its under side, this is its sucking
proboscis, and serves as a means of attachment as well as an organ of feed-
ing.’ The San José scale is very prolific. It was ascertained at Washington
that there are four regularly developed generations and possibly part of a
fifth ina year. It is estimated that about 200 females (and about the same
number of males) are given birth to by each female. Thus the descendants
of a female amount to 3,216,080,400 individuals. From this it can easily
be seen how destructive to fruit trees this pest soon becomes. It is now
found in every state and territory and in Canada. Many states have
laws to try to prevent its distribution with nursery stock.

Perhaps the most effective remedy is the fumigation of orchard trees by
hydrocyanic gas. To do this the tree is entirely enclosed in a large tent
and the gas generated under it “ by pouring about 50 ounces of water into
5 ounces of commercial sulphuric acid and dropping into it 15 ounces of
cyanid of potassium.’ These amounts are sufficient for a tree 12 feet high
with a spread of 10 feet. The fumes are deadly poison. Of sprays for
leaves and greenhouse plants, crude petroleum and kerosene emulsion are
best. Protection of the birds is one great means of holding these pests in
check. It has been proved by the examination of 226 stomachs that more
than one-fifth of the food of the blackheaded grosbeak (Zamelo’dia melano-
ceph’ala') consists of scale insects. For the work (Fig. 118) of ladybird
beetles see p. 147.

ORDER VIII. COLEOP’TERA

This order consists of eleven or twelve thousand species in
America, north of Mexico.

The mouth parts of beetles (Fig. 119) consist of the upper
lip or labrum, the jaws or mandibles for seizing the prey or for
gnawing; the complicated many pieced marille with usually
prominent maxillary palpi; the lower lip or labium of several
parts, and rather large labial palpi. These mouth parts are
adapted for biting, and are not easy for beginners to identify.
The student should identify these parts on a large beetle with
the help of a good figure (Fig. 119) and a good magnifying
glass.

Compound eyes are present, but usually the simple eves are
wanting.

The wings are four in number, except in some ground beetles,
which have only the anterior pee The anterior wings are

1 Plate III, Bulletin 32, U. 8. Biological Survey.

COLEOPTERA 149

quite rigid and meet in a line on the back, forming a sheath to
inclose the membranous posterior wings, which fold up under
the fore wings or elytra when not in use.

The body is usually compact. The under surface of the
abdomen is hard, but the upper surface beneath the elytra is
soft and yielding, thus permitting respiration.

Fig. 119.—Under surface of Har’palus caligin’osus: a, Ligula; 6b, para-
glossa; c, supports of labial palpi; d, labial palpus; e, mentum; f, inner lobe
of maxilla; g, outer lobe of maxilla; h, maxillary palpus; i, mandible; &,
buccal opening; J, gula or throat; m, m, buccal sutures; , gular suture;
v, prosternum; p’, episternum of prothorax; p, epimeron of prothorax;
qq, 7", coxe; r, 7’, r”’, trochanters; s, s’, s’’, femora or thighs; ¢, ¢’, ¢’’,
tibie; v, v*, v3, etc., ventral abdominal segments; w, episterna of mesothorax
(the epimeron is just behind it); x, mesosternum; y, episterna of meta-
thorax; y’, epimeron of metathorax; z, metasternum. (After Leconte.)

The Young.—The metamorphosis is complete. The larve
are usually called grubs. (See Fig. 120, p. 150.) Their habitats
vary much. Some live in trees, others, as the larve of the tiger
beetle, burrow in the gound, and, with the head at the sur-
face, watch for their prey. Their food varies according to the

150 BRANCH ARTHROPODA

habitat. The burying beetles (Fig. 120) (Nécréph’orus) pro-
vide food for their young by burying carrion, as a dead mouse or
bird. When it is covered over with earth the female lays her
eggs upon the carcass. They soon hatch and the larve feed
upon the food thus provided for them.

The food of the adult Coleop’tera also varies much. Some,
as the ground beetles (Carab/ide), are predaceous. Others, as
the carrion beetles, feed upon decaying animal matter, while

Fig. 120.— Necroph’orus burying a mouse, und larva. (Landois.)

others, as the Colorado potato beetles, are voracious plant
feeders, making this order of much economic importance.

Other familiar examples are the apple-tree borers, the
wire-worms, fruit and grain weevils, and the white grubs of the
June beetles (Fig. 121).

The tiger beetles (Cicindel’id@) are usually of a beautiful metallie green
or bronze, banded or spotted with yellow, though some are black, while
those living in white sand are exactly the color of the sand. They are
the most. active of all beetles, running and flying well. They may be
found on bright warm days on dusty roads or along the banks of streams.

COLEOPTERA 151

Comstock says they remain still until within our sight, but out of reach,
and then ‘ like a flash they fly up and away, alighting several rods ahead
of us,” with eyes toward us. The ugly larve live in vertical burrows
about a foot deep on beaten paths or in the sand. The larva, with its dirt-
colored head which is bent at right angles to its lighter colored body, plugs
the entrance to its burrow, and with its wide-open jaws forms a living
trap for passing insects. On the fifth abdominal segment there is a hump
bearing two hooks curved forward, by which the larva holds fast, thus pre-
venting large prey from dragging it out of its burrow.

The ground beetles (Fig. 122) (Carab’ide) are probably the most im-
portant family of predaceous insects, though a few species are vegetable
feeders. They are usually dark colored and nocturnal, but some are large
and brilliantly colored, and the wing covers are generally ‘ ornamented
with longitudinal ridges and rows of punctures.’’ They hide in daytime
under stones and logs. There are about twelve hundred species in North

Fig. 121.—June beetles: 1, Pupa; 2, larva; 3, 4, adult. (Riley, Report of
State Entomologist of Missouri.)

America. The larve of most of them are long flattened grubs, with body of
uniform breadth throughout, protected on top by horny plates, ending in a
pair of conical bristly appendages. Usually they bury themselves just
beneath the surface and feed upon insects which enter the ground to
pupate. They destroy large numbers of leaf-feeding beetles or their
larve. They pupate in small round cells in the soil, from which the adults
push their way out.

The caterpillar hunter (Caloso’ma scruta'tor) is a familiar example of the
ground beetles (Fig. 122). Its wing covers or elytra are bright green or
violet, margined with reddish. It is found on trees at dusk. It is known to
climb trees and make raids upon the hairy tent caterpillar, hence it is a
friend. Two others (Calosoma frigidum and C. calidum) are hunters of cut-
worms and canker-worms. The latter is sometimes called the fiery hunter,
from the rows of reddish pits on its black elytra.

Another one (Agonod’erus pal'lipes) feeds upon sprouting corn.

152 BRANCH ARTHROPODA

The carnivorous water beetles (Dylic'ide), of which there are three
hundred species, are found everywhere in streams and ponds (Fig. 123).
They vary in length from } to 1} inches. The diving beetle projects the tip

Fig. 122.—Ground beetle (Calosuma), similar to C scrulalor; below, a
Carabus. (Brehm.)

of its abdomen through the surface film to breathe. It raises the elytra a
little, and the air which is caught under them is held by the fine hairs on the

Fig. 123.—Carnivorous water bectles. (Brehm.)

back, where the spiracles are situated. Thus, it carries « supply of air
which enables it. to breathe under water. These beetles make interesting
aquarium specimens.

DIPTERA 153

Platypsyl'la casto’ris is the sole representative of the family Platypsyl’lide.
This queerly shaped beetle lives a parasitic life upon beavers. It 1s wingless
and blind, and the elytra are rudimentary and short, exposing five abdomi-
nal segments. Its degeneration is due to its parasitic life.

The lady-bugs (Coccinel'lidw) are interesting little predaceous beetles,
yellow or reddish, with black spots. The cottony cushion-scale (Jce’rya
purchasi), so destructive to California fruits, was subdued by a lady-bug
(Veda'lia cardindlis) brought from Australia to feed upon it. The hop
louse is destroyed by the larve of certain lady-bugs known as “ niggers.”
The lady-bugs, with few exceptions, are predaceous. One (Epilach'na
borea'lis) is herbivorous. Its larva, which is yellow and clothed with
forked spines, feeds upon the leaves of the squash family.

The little carpet beetle (Anthre’nus scrophula’rie) is a household pest.
Its larva feeds upon carpets, furs, feathers, and woolens.

The fireflies (Lampyr'id@) or ‘‘ lightning-bugs ”’ are not flies, but beetles.
The light giving has never been fully explained. “ The light-giving organ
is usually situated just inside of the ventral wall of the last segments of the
abdomen, and consists of a special mass of adipose tissue richly supplied
with air-tubes (trachee) and nerves. From a stimulus conveyed by these
special nerves oxygen, brought by the network of trachez, is released, to
unite with some substance of the adipose tissue, a slow combustion thus
taking place. To this the light is duc, and the relation of the intensity or
the amount of light to the amount of matter used up to produce it is the
most nearly perfect known to physicists.’

Myrmecoph’ilous Beetles.—There are nearly one thousand species
of beetles which live in the nests of ants. Many of them are commensal
with the ants, deriving perhaps the greater benefit by the association, but
others live truly symbiotically with their hosts.2 They secrete a sweet
substance which is eaten by the ants, which in return shelter, clean, and,
by regurgitation, feed them. They are strangely modified for this mode
of life, usually by degeneration.

ORDER IX. DIP’TERA

This order contains about fifty thousand species, of which
about seven thousand are known in America. It includes some
famous flies (Fig. 124).

The mouth parts are adapted for piercing and sucking or for
lapping. Just what constitutes these mouth parts is a contro-
verted question among scientists. Comstock says, ‘“‘ According
to the most generally accepted view the six bristles represent
the upper lip (labrum), the tongue (hypopharynx), the two
mandibles, and the two maxilla, and the sheath enclosing these
bristles is the lower lip (labiwm).’’ Identify these parts on the
head of a big fly with the aid of a large figure and a magnifying
glass.

1 Kellogg, p. 269. 2 Kellogg, p. 553.

154 BRANCH ARTHROPODA

The Wings.—As the ordinal name indicates, these insects
have two membranous wings. No fly has more than two
wings and only a few are wingless. They have, however,
vestiges of a second pair, called halte’res or balancers, ending in
short knobs. They are used in directing the flight and are be-
lieved by some to be auditory organs.

Family Mus’cida.—The common house-fly (Mus’ca domestica) is too well

known for our comfort. It hibernates. One will recall having seen flies
about the house during the winter. They breed about stables in the sum-

Fig. 124.—Typhoid fever or house-fly (Mus’ca domes’tica): a, Adult male;
b, proboscis and palpus of same; c, terminal joints of antennz; d, head of
female; ve, puparium; f, anterior spiracle; all enlarged. (Howard and
Marlatt, Bull. U. 8. Dept. of Agriculture, 1896.)

mer. The eggs, numbering about one hundred, hatch in about twenty-
four hours. The soft, white, cylindric, footless larva is called a maggot.
It feeds and grows for about a week, molting twice, and then pupates
within the larval skin, or pupariwmn, for another week. It then makes a
circular opening in the puparium and emerges as the adult fly, thus giving
time for a number of generations. In a summer the offspring of a single
fly may reach incredible numbers. It is now known that. the principal in-
sect agent in the spread of typhoid fever is the common house-fly, and
great care should be taken to prevent its breeding. All human and horse
excreta should be kept in fly-tight vaults and sprinkled with chlorid of
lime or quick lime at least once a week, unless wanted for fertilizing
purposes. All garbage cans and swill pails should be kept covered, and

DIPTERA 155

sprinkled with lime when emptied. Chicken pens should be cleaned often
and sprinkled with lime.

The many little projections on the feet of the fly are tubular, and secrete
a sticky fluid which enables it to walk upside down.

The blow-fly and the flesh-fly, close relatives of the house-fly, lay their
eggs upon meat, cheese, and other provisions or upon decaying animal sub-

7 thorax .

“a !
YF tarsus
Yerite rs al
‘ oint

‘ white banded

basal segme nt

basal band---

basal end of segment.
apreal_end of segmen

2 toesal Jornal

tarsal yornt

t ersal yen a
Bly Ra ey ctersal clawg--
on st tarsal gant
Fig. 125.—An adult mosquito, much enlarged, with all the parts that are
used in classification named. (Smith, N. J. Experiment Station, Bulletin
171, 1904.)

stance, on which the maggots feed. Thus, while a great annoyance, they
may do some good by acting as scavengers. The most common flesh-fly
is perhaps Sarcoph’aga sarrace’nie, which resembles a large house-fly. It
furnishes another example of viviparous insects; in other words, the larve
are brought forth alive.

156 BRANCH ARTHROPODA

Horse-flies (Taban’id) arc also pests of man and beast. | They are
most abundant in the hot summer days. The large black-bodied horse-
flies, of which there are a hundred specics, belong to the genus J’abanus.

The Bot-flies (Ce'stride).—“ The horse bot-fly (Gastriph'ilus e’qui) closely
resembles the honey-bee in form, except that the female has an elongated
abdomen curved under the body.” Horses have an instinctive fear of this
fly. It attaches its eggs to the hair of the legs and shoulders of the horse,
and they are taken into the mouth by biting the irritated place. The
larvee fasten themselves to the lining of the stomach. When grown, during
the fall and winter, they pass out and develop within a puparium.

The oxwarble larve ( Hypoder' ina linea'ta) live just beneath the skin on the
backs of cattle, which are made frantie by their burrowing.

The sheep bol-fly deposits its larvee in the nostrils of sheep, antelope, ete.
They work up into the frontal sinuses and horns and cause the ‘* staggers.’”!

Reindeer, decr, rabbits, and squirrels are infested by larvir of species of
bot-flics, and one or two species infest man.

Fig. 126.—1, Egg-mass of the common mosquito; 2, larva breathing
at the surface of the water; 3, a pupal mosquito. (From Hampton
Leaflet.)

Mosquitoes (Culic’ide) (Fig. 125) seem too well known to need descrip-
tion, but there are other insects so similar that they are often mistaken for
them. Comstock says ‘‘ the most distinctive feature of mosquitoes is the
fringe of scale-like hair on the margin of the wing and also on all known
American forms on each of the wing veins.”’ The males differ from the females
in having feathery antenne and in the absence of the piercing stylets. As
a rule they do not sing or bite, and probably feed upon the juices of plants,
as do the females if they cannot “get blood.” The larvee (Fig. 126), called
“ wrigglers”’ or “ wiggle-tails,” are too often found near our dwellings in
rain-barrels, slop-pails, open cisterns, open sewers, water troughs, lily-tubs,
ponds, anywhere where the water is allowed to remain long enough for their
development, which requires from cight to eighteen days. Of the three
principal genera, Cilex contains most of our mosquitoes whose bite and song
are well known. <Avnoph’eles is the genus which is the intermediate host
and the transmitter of the malaria germ. Of course it cannot transmit

1 Comstock, p. 478; Hertwig, p. 493.

DIPTERA 157

these germs unless it has been infected with them itself.

Stegom'yia

fascia’la (Fig. 127) is the yellow-fever-carrying species, so much dreaded in

our southern states. It has been
established by observation and ex-
periment! that these mosquitoes, if
they have bitten persons affected by
malaria or yellow fever, actually
carry these diseases, also that Steg-
omyta fascia’ta and Cu’lexr fati’gans,
var. skusit, and Anoph’eles rossit
carry certain forms of filariasis.
These organisms belong to the
round worms or Nematoda (see
p. 41). The most common form of
filariasis is elephantiasis. In this
disease the legs and arms are af-
fected. One leg may become so
enlarged as to weigh as much as
the rest of the body, or the arm
may become a foot thick and horri-
bly repulsive. In Samoa, says Kel-
logg, fully one-third of the natives
are attacked by this incurable dis-
ease, which, though slow and almost
painless, is certainly fatal. Ma-
laria, so widespread in the United

larged).
of Agriculture, 1902.)

Fig. 127.—Stegom’yia fasci'ata (en-
(Howard, Bull. U.S. Dept.

States, becomes even more prevalent and more often fatal in the tropics.

Millions die from it every year.
of malaria in India alone.

In a single year five million persons died
Hence the mosquito is to be classed not sim-

ply as a great annoyance, but as an insidious foe to health and life.

Fig. 128—The common harmless
mosquito stands this way on a ver-
tical or horizontal surface. (From
Hampton Leaflet.)

The common mosquito, Culer (Fig.
malaria-carrying form (Fig. 129) in several ways.

Fig. 129.—The malarial mosquito
stands with its head pointing down-
ward at an angle of from 20 to 30
degrees from a vertical or horizontal
surface. (From Hampton Leaflet.)

128), may be distinguished from the
The female Culex has

1 Kellogg, pp. 617, 630.

158 BRANCH ARTHROPODA

short palpi, while the Anoph’eles has palpi nearly as long as the beak, making
three long projections on the head. It may be distinguished also by the
way it alights. The Culex is “ hump-backed ” with the beak pointing down-
ward, while in the Anopheles the body and beak lie in the same plane. The
eggs of Culex are laid in a boat-shaped mass, while the eggs of Anopheles
are laid “ singly and at random,” but run together, forming irregular groups
or strings. The larva of Culex hangs with the head down, so as to keep the
end of the respiratory tube, which is borne by the next to the last somite, in
contact with the air. The larval stage lasts about five or six days or longer
in unfavorable conditions. The larva of Anopheles has a very short respi-

“

Fig. 130.—A fine breeding-place for mosquitoes. (Hampton Leaflet.)

ratory tube, and consequently lies in a horizontal position just under the
surface film in order to obtain air. (This explains how it is that kerosene
oil “poured upon the troubled waters” destroys the larva. They are
simply drowned or suffocated as the surface film of oil excludes the air.)
The larval stage lasts from twelve to fourteen days.

The mosquito larva, after growing several days and molting twiee, changes
into aclub-shaped pupa (Fig. 126), the head and thorax being greatly en-
larged, while the abdomen is slender. At the caudal end is a pair of leaf-
like locomotor or swimming appendages. It takes no food, and when un-
disturbed it floats upon the water, but when disturbed it is active, thus differ-

DIPTERA 159

ing from the pupal stage of most insects. The pupa of Anopheles has a
narrower and more pointed head and much shorter and wider breathing
tubes than those of Culex.

Mosquitoes flourish alike in the heated moist regions of the tropics and
in the frigid regions of ice and snow. Many species have their haunts and
breeding-places in fresh water, others breed abundantly and some perhaps
exclusively in brackish water. They are found even in arid regions far
from water, where it is probable they lay their eggs in the ground. So,
go where we will, we cannot escape them, we must fight them.

Fig. 131.—Wheat plant, showing injuries by Hessian fly: a, Egg of Hes-
sian fly; b, larva; c, flaxseed; d, pupa or chrysalis; e, female, natural size;
f, female; g, male; h, flaxseed or pupal stage between the leaves and stalk;
2, chalcidid parasite; all enlarged except wheat stem ande. (After Riley,
Burgess, and Trouvelot.)

A very easy and successful way of getting rid of mosquitoes in a pond
which will sustain fish is to stock it with such fish as the ‘ top-minnow,”
sun-fish, and stickleback, whose young especially feed upon the larve.
Dragon-flies also should be encouraged and protected, since their nymphs
feed upon the larve of mosquitoes, and the adults are voracious feeders
upon the mosquitoes. In fact, if it were not for the dragon-flies, life in the
Hawaian Islands would be almost intolerable on account of the hordes of
mosquitoes. Pools and marshes should be drained, or, if the pool or mud-

160 BRANCH ARTHROPODA

puddle is small, it may be filled up with less expense. If neither can be
done, then spraying with kerosene along the edges of the banks and the
surface of the water every two or three weeks should be resorted to. The
oil kills by contact many adults and larve among the grass and weeds, and
by coating the surface of the water with a film of oil the ‘ wiggle-tails ”
are suffocated. Many females also are killed by this film of oil when they
return to the surface to deposit their eggs. All open barrels (Fig. 130)
and cisterns should be screened, so that the female mosquito cannot get to
the water to deposit her eggs. .

The gall-gnats (Cecidomyi’ ir) are the smallest flies, but their great num-
bers and their gall-forming habits make them great enemies of plants.
There are about a hundred species in the United States, most of which are

“DIPTERA: HYMENOPTERA:

Volucella 1NANS. Vespa Vurcaris.

Volt «+ Bome YLANS, Bomaus Larivarius.

Fig. 132.—Two cases of mimicry: flies resembling a wasp in the one, and a
bee in the other. (Romanes.)

destructive to cultivated plants. The minute reddish or white eggs are
deposited on or in living plants, and the maggot-like larvee probably imbibe
their food through the skin.

The Hessian fly belongs to this family. It is a tiny blackish midge which
lays its eggs (Fig. 131) in the sheaths of leaves some distance from the
ground. The larva lives between the base of the leaf and the main stalk
and feeds upon the sap of the growing wheat. There are four or five broods
a year, both spring and winter wheat being infested. It is estimated that
the ravages of this insect cost the farmers of this country $10,000,000
annually. Were it not for its natural enemies, a half-dozen hymenop-
terous parasites, it would soon take the whole crop of wheat, rye, and
barley, The chief remedies which the farmer can use are the late planting

SIPHONAPTERA 161

of winter wheat; the burning or plowing of stubble; the early planting of
strips of decoy wheat to attract the egg-laying females to deposit their eggs,
and then to be burned; and the rotation of crops.!

Another common and conspicuous gall-gnat is the pine-cone-willow gall-
gnat, which lays its eggs in the newly formed buds ofthe willow. The
stem ceases to grow, but the leaves continue, causing the bud to resemble a
pine-cone. In this the larva remains through the summer and winter,
pupating in early spring, soon after which the adult emerges. There are a
number of others, as the clover-leaf midge, the clover-seed midge, and the
wheat midge, each injurious to its respective crop.

The Syrphus flies (Syr’phide), of which there are twenty-five hundred
species, differ much. Some species in- the adult form imitate bees and
wasps (Fig. 132). They can be distinguished by the longitudinal ‘ spu-
rious”’ vein between veins three and five. Some of the larve are found in
ants’ nests and some in the nests of bumble-bees and wasps. One of the
commonest is the yellow-banded species of the genus Syrphus, whose larvee
do great good by destroying aphids, in whose colonies they live.

The larve of one of the bee-flies (Bombyli’td@) are also friends of man.
They destroy many grasshoppers by burrowing into the egg-cases and
devouring the eggs. The adults of these maggot-like larve are swift,
hairy, and bee-like, mimicking the bee in appearance and feeding habits.

ORDER X. SIPHONAP’TERA

The fleas consist of a single family, the Pulic’ide, of nearly
one hundred and fifty species, about fifty of which are found in
the United States. Until recently the fleas were regarded as
degenerate wingless Diptera, but entomologists now place
them in a separate order. They are found usually as temporary
external parasites on the cat, rat, rabbit, dog, poultry, and
man.

The mouth parts are adapted for piercing and _ sucking.
They are almost wingless, the wings being represented by mere
scaly plates. The bodies are naked, smooth, hard, oval, and
compressed. The metamorphosis is complete (Fig. 133).
The ‘small, slender, white, footless, worm-like grubs” are
composed of thirteen segments. They seem to live on dry dust
and the organic matter it contains. When grown they usually
spin a silken cocoon and pupate in the dust. In the species
infesting cats and dogs the larval life lasts only about a week.
The development from the egg to the adult requires but two
weeks. Fresh pyrethrum dusted about the rugs where dogs
and cats lie, or spraying the rugs with formalin, will help get
rid of fleas.

1 Jackson and Daughterty’s “‘ Agriculture through the Laboratory and
School Garden,”

11

162 BRANCH ARTHROPODA

The chig’oe, a small flea of the West Indies and of South America, often
causes serious trouble by burrowing under the toe-nail or the skin of the foot
of man. The female burrows under the skin, becomes encysted and dis-
tended by the eggs which hatch here, and unless the young are carried out
by the pus they probably develop here.

Fig. 133—Common cat and dog flea (Pii'ler serrtit’iceps): a, Eggs; b,
larva in cocoon; c, pupa; d, adult; e, mouth parts of same from side; f,
labium of same from below; g, antenna of samc; all much enlarged. (How-
ard, Bull. U. 8S. Dept. of Agriculture, 1896.)

Rat Fleas.—It is believed that in tropical countries the disease germs
of the bubonic plague may be transmitted from rats to men by the bites or
punctures of rat fleas.

ORDER XI. LEPIDOP’TERA

This order includes such common insects as butterflies and
moths or “millers.” There are more than 6600 species in
North America.

The head is rather small for the size of the body.

The mouth parts are highly complex, a striking example of
adaptation of structure to function. The two maxill are greatly
modified into a long hollow tube (Fig. 141) for sucking the juices
of fruits or the nectar of flowers. When not in use this tube,
tongue, or proboscis is coiled up between two projections, the
labial palpi. Many moths do not feed in the adult stage and
the maxille are lacking. The other mouth parts are mere

LEPIDOPTERA 163

rudiments. Find these rudiments on a large specimen and
compare with the mouth parts of the grasshoppcr.

The compound eyes are large and conspicuous.

Some of the Lepidoptera have ocell,! one on either side above
and near the margin of these compound cyes, but they are usually
hidden by the scales covering the head.

The many jointed antenne are very various in size, shape, and
color.

The thorax bears three pairs of legs and two pairs of wings.
The wings are large, membranous, and covered with overlapping
scales, which are, in reality, modified hairs. These scales
strengthen the wings and give coloration to the species.

The abdomen has no paired appendages.

The metamorphosis is complete. The larve of Lepidoptera,
are commonly called caterpillars. They are very destructive,
being almost without exception injurious to vegetation. Com-
stock says, ‘‘a very few feed upon plants below the surface of
the water.’’ The species which destroys scale-bugs, also those
attacking woolen cloth, feed upon animal matter. Caterpillars
are usually cylindric. The thorax bears six clawed, jointed,
tapering legs, which develop into the legs of the adult. The ab-
domen bears from two to ten thick, fleshy, non-jointed, contrac-
tile pro-legs (see figure of silkworm, p. 126), which are shed at
the last molt. The pro-legs are usually surrounded at the ex-
tremity by many minute hooks. The mouth parts of caterpil-
lars are formed for biting, hence they can be exterminated by
the arsenical poisons when it is safe to use them.

The Lepidoptera pupate in chrysalids or cocoons. The
adult stage is the familiar winged form. It does no harm except
the occasional puncturing of fruit to get the juice.

Distinctions Between Butterflies and Moths—The antenne of
butterflies are filiform or thread-like for most of their length, but
the end is thickened into a spindle-shaped enlargement or club.
The antenne of moths are of various forms, usually filtform or
pectinate (feathery), but never clubbed. Butterflies are diurnal,
while the moths are crepuscular or nocturnal. Butterflies
at rest fold the wings together in a vertical position above the
back. Moths spread the wings horizontally, or fold them leaf-

1Comstock, p. 199.

164 BRANCH ARTHROPODA

like, or wrap them about the body, but never hold them in a
vertical position.

The skipper butterflies are diurnal, but, unlike other butter-
flies, the antenne are usually recurved, forming hooks. Their
bodies are more robust than those of other butterflies. They
fold the wings, sometimes only the front ones, vertically when
at rest. The skipper caterpillars are distinguished from other
caterpillars by the unusually large head and the much constricted
neck. Skippers spin thin cocoons of silk in which to pupate.

Authorities enumerate 650 species of butterflies in the United
States east of the Mississippi River. Kellogg gives six families of
butterflies and forty-four of moths. Of the thousands of species
with their various and interesting habits only a few can be
mentioned. These should serve to stimulate the student to
observe and study others. See “ Laboratory and Field Guide”
for collecting, breeding, and mounting.

The carpenter moths (C0s’side), of which there are twenty species in North
America, are, in the larval stage, wood-borers, burrowing about in the heart-
wood of shade and fruit trees. Pepper and salt gray moths, indistinctly or,
in a few cases, conspicuously marked with black and white, lay their eggs
on the bark of trees, where the naked, grub-like larve burrow into the wood.
Here they tunnel through the wood for two to four years, according to the
species. In this tunnel the pupal stage is spent. When ready for the adult
stage the pupa works its way, by backward projecting saw-like teeth on the
abdomen, to the opening of the tunnel, from which the moth emerges.
aa empty pupa skins may often be found projecting from the deserted

urrows.

The meal moth (Pyr’alis farina’lis), whose larva feeds upon meal, flour,
or old clover-hay, is a common species. It is usually found near the larva
food, but sometimes sits upon the ceiling with its tail curved over its back.
Its expanse of wing is about an inch. The wings are light brown with red-
dish reflections and a few wavy transverse lines. The larva makes long
tubes of silk in the meal. Perhaps the most formidable mill pest is the
Mediterranean flour moth (Ephés'tia kuchnitl‘la). The caterpillars spin
silken galleries through which they pass, making the flour lumpy and stringy.

The coccid-eating pyralid (Lelil’a coccidiv'ora) differs from other
members of its family in being predaceous. It feeds upon the eggs and
young of several scale insects. The larva spins a silken tube or bag, in
which it lives.

The codling moth (Carpocap’sa pomonel’la) (Fig. 134) is one of the best-
known and most cordially hated of moths. It causes an annual loss in the
United States of $10,000,000. The adult is small, with finely mottled, ash-
pray orrosy fore wings. Near the square ends of these wings is a large brown-
ish spot marked with metallic, bronze bands. The hind wings and abdomen
are a lustrous light yellowish brown. This moth lays its eggs singly in the
blossom end of an apple, just when the petals fall. When the larva hatches

LEPIDOPTERA 165

it eats its way into the core. The affected fruit usually falls to the ground
before ripenmg. The full-grown larva burrows out of the apple and
pupates in a cocoon under the rough bark of a tree. After two weeks in the
pupal stage the adult of the first brood emerges and lays its eggs on later
apples. The larve are carried into the cellar with the fall and winter ap-
ples, pupate in the crevices of the barrels or boxes, and remain till the fol-
lowing apple-blossom time. Spraying the fruit with Paris green soon after
the petals fall and again in about two weeks will greatly reduce the loss.
At this time the fruit stunds with the blossom end up and the poison will
then reach the place where the larva hatches.”! The larva does not remain
long in the apple after it falls to the ground. Hence if the apples are burned
or fed to hogs at once the larve will be destroyed.

Fig. 134.—The codling moth: a, Apple showing burrow; b, place where
the worm entered; d, chrysalis or pupa; e, larva or worm; f, moth with
wings closed; g, moth with wings spread; h, head end of larva; 7, cocoon
in which the larva changes to a chrysalis. All about life size except h.
(Riley.)

The geometrids are of interest because of the peculiar phase of protec-
tive resemblance possessed by their larve. They cling by their posterior
legs to the branches of trees or other plants, and, holding the body out
straight, stiff, and still, look, for all the world, like short, stubby branches.
My little daughter searched for fully five minutes within a few inches of a
green specimen on a sweet-pea vine before discovering it. When disturbed
the caterpillar swings down by asilken cord till it reaches the ground. Most
of them are leaf eating and they are sometimes so numerous as to do great
injury. Among them are the canker-worms (Fig. 135), currant span-
worms, two or three species which feed upon the grape, and the raspberry
geometrid. They maybe poisoned by Paris green, since all insects with
biting mouth parts can be killed by poisoning the food with arsenical
sprays.

1 Jackson and Daugherty’s “‘ Agriculture,” p. 321.

166 BRANCH ARTHROPODA

The owlet moths (Noctu'idir), of which there are more than twenty-five
hundred species in America, fly at night and are familiar visitors around our

Fig. 135.—The spring canker-worm: a, Egg mass, natural size; b, egg, mag-
nified; c, larva; d, female moth; e, male moth. (Riley.)

evening lights. To these belong the numerous cut-worm moths and army
moths. Most of this large family are inconscipuous and dull colored, but

Fig. 136.—The boll-worm or corn-ear-worm. (Riley.)

the group of “ underwings,” or Catoc’alas, are exceptions to this rule.
Strangely enough it is their posterior or under wings which are conspicu-

LEPIDOPTERA 167

ously colored and banded. When at rest the inconspicuously marked

dull-colored fore wings completely cover the hind wings. During the day

the moths rest close against the bark of tree trunks, where it is almost. im-

possible to distinguish them. Collectors smear syrup on the trunks of

trees where no sweet-smelling flowers are near, and collect the insects thus

ae on a dark, damp night, with a dark-lantern and wide-mouthed
ottles.

The cotton worm (Alé’tia argilla'cea) also belongs to this family. It
feeds upon the leaves of the cotton plants. The cotton boll-worm ( Helio’-
this armig'cra) (Fig. 1386) feeds upon the pods or bolls. The destruction
caused by these two caterpillars causes an annual loss of millions of dollars

||

il

Fig. 137.—Corn-worm eating an ear of corn. (Quaintance, F. B. 191,
B. Ent. U. 8. D. A.)

to the cotton growers. The boll-worm has become a great pest in the
north also as the corn-ear-worm (Fig. 137). Just at the roasting ear
stage it eats the juicy kernels and leaves a disgusting dark furrow, unfitting
the corn for use. It feeds upon the fruit of the tomato also. The naked,
greenish-brown caterpillar is marked longitudinally with darker stripes when
grown and is about 14 inches long. It pupates in the ground through the
winter. The moth has dull yellowish fore wings tinged with green.
The hind wings are paler. Since it works under cover of the husk, spray-
ing is of no use. Fall plowing practised by all neighbors having infested
corn will materially lessen the number of worms. As the moths fly well, it
would do comparatively little good for one to plow unless the near neigh-
bors unite in the effort. Rotation of crops is helpful.

168 BRANCH ARTHROPODA

The tussock moths (Lymantri'ide) (Fig. 138) are of medium size, the
antenne of the males being more broadly pectinated than those of the
females. Ocelli are lacking. In some specics the females are wingless.
The legs are woolly or hairy. The larve are more beautiful than the adults.
They have several bright colored tufts of hair on the back and long pencils

Vig. 138.--Orgyia leucostig’ma: a, Larva; 6, female pupa; c, male pupa;
d, c, male moth; f, female moth; g, same ovipositing; h, egg-mass; 7, male
cocoons; k, female cocoons with moths carrying eggs. All slightly en-
larged. (Howard, Farmers’ Bull., U. 8. Dept. of Agriculture, 1899.)

of hair on each end of the body. The sixth and seventh segment each
bears on the back a coral-red seent gland. — It is casy to guess whether these
caterpillars are a favorite food of birds. They infest our shade and orchard
trees. The eggs are usually deposited upon the cocoon from which the adult
female has just emerged, so they may be destroyed by collecting and burn-
ing the cocoons in winter.

LEPIDOPTERA 169

Fig. 139.—A, Male, and B, female, gypsy moths. Natural size. (Forbush
and Fernald.)

/S/ THE EGGS REMAIN ON THE TREES a
LS! VINE MONTHS IN THE YEAR;THE MOST 2 \
3] VITAL PERIOD, IN THE LIFE OF 2a)
« THE GYPSY/LEFE\MOTH =e
yee YCL ==
\G a
U2 : ‘ a
~x<

Fig. 140.—The life cycle of the gypsy moth. (Figures after Forbush
and Fernald.) (Bull. No. 121, New Hampshire State Experiment Sta-
tion, December, 1905.)

The gypsy moth (Ocne’ria di’spar) (Fig. 139), imported from Europe in
1868, has become a great pest of forest and shade trees in Massachusetts.

170 BRANCH ARTHROPODA

The state fought it in every possible way, employing hundreds of men in
spraying, trunk-banding, and egg-collecting. From 1890 to 1900 Massa-
chusetts spent more than a million dollars in keeping this moth in check.

The hawk moths (Sphin‘gida), sphynx moths (Fig. 141), or humming-
bird moths have a stout, spindle-shaped body and long, narrow, exceed-
ingly strong wings. The suck'ng tube is very long, sometimes twice as
long as the body. When not in use, it is coiled up beneath the head like a
watch-spring. Their rich varied tints of olive, tan, black, or yellow, always
subdued, save for an occasional dash of bright. color on the under parts,
mark them as rarely beautiful creatures. As a rule, these moths love the

Fig. 141.—Tomato-worm or tobacco-worm: larva, pupa, and adult.
(After Walsh and Riley, Am. Ent.)

twilight, and strangely resemble the humming-birds from their habit of rap-
idly vibrating their wings while poising themsclves over a flower and suck-
ing its nectar.

The larva, naked and cylindric, usually has a ‘‘ horn ” on the back of the
eighth abdominal segment. These caterpillars are usually green with
several oblique light-colored or whitish lines on each side (see Fig. 141).
When resting these caterpillars “ rear the front of the body up in the air,
curl the head down in a most majestic manner, and remain thus rigidly
motionless for hours.’’! They are thus supposed to resemble the Kgeyptian
sphynx, hence the name, sphynx moth. They feed upon the leaves of

1 Kellogg, 331:

LEPIDOPTERA 171

various trees or plants, the tomato-worm being perhaps the most familiar
example. When full grown this is sometimes 3 inches long. The pupa,
which lies buried in the ground, has a firm, naked, dark brown wall, and is
distinguished by the peculiar ‘‘ jug-handle” sheath, in which the sucking
tube is developed. Hand picking of the larve, fall plowing, and rotation
of crops are the best remedies.

Fig. 142.—Metamorphosis of monarch butterfly (Anosia plerippus):
a, Egg; b, larva; c, pupa; d, imago or adult. (From Jordan and Kellogg,
“ Animal Life,’”? D. Appleton and Co., Publishers.)

The monarch or milkweed butterfly (Ano’sia plexip’pus) (Fig. 142)
is one of our most abundant species. Hundreds or even thousands of
these butterflies may sometimes be seen in a swarm, or “ roosting’ together
in trees. Their wings are reddish brown, bordered with black, and the

veins are edged with black. There are two rows of white spots on the outer
margins.

172 BRANCH ARTHROPODA

The larva when grown is a very light green or greenish yellow, and
regularly marked with shiny black and yellow bands. On the second
thoracic and the eighth abdominal segment there is a pair of slender, fleshy,
black filaments. This caterpillar feeds upon the leaves of the mmilkweed.
It attains its growth in two or three weeks, when it pupates from nine to
fifteen days in a smooth, bright green chrysulis (Fig. 142), which is
about an inch long and beautifully adorned with a few black and gilt spots
and bands. In the South there are two generations, but with us but one.

The butterfly is protected from its enemies, the birds, by an ill-tasting
acrid fluid, of which its conspicuous color gives warning. The power of
flight is strong and these butterflies migrate in winter. The monarch
is found all over North and South America and in most of the Pacific
islands, and in Australia and Western Europe.

It is closely mimicked by the viceroy (see Fig. 92, p. 119), a smaller
butterfly which is not distasteful, but is protected from the birds by its
resemblance to the odious monarch. The viceroy may be easily dis-
tinguished by the transverse band of black on each of the hind wings.
Its larvee feed upon the willow, poplar, and cottonwood. The larva hiber-
nates in a silk-lined nest made of a rolled leaf. ~

The swallow-tailed butterflies (Papilion’id@) are a large and interesting
family, having a sort of half-fluttering, half-soaring flight. They are
easily distinguished by their large size and their black and yellow—or
greenish-white—tiger-like markings. Twenty-one species are found in the
United States. The wings are very thickly covered with scales. They
are narrow and the posterior wings end in a club-shaped prolongation which
is supposed to call the attention of the bird to the less vital part. The
larvee when disturbed project a pair of bright colored fleshy “horns” from a
slit in the dorsal wall of the prothorax. The horns exhale an odor which in
some species is exceedingly disargeeable.t

The zebra swallow-tail ([phicli’dvs ajax) differs from all other butterflies
of the eastern United States by the black and greenish-white bands on its
wings and by its exceedingly long ‘‘ tails.” This butterfly is extremely
interesting to the scientist, in that it furnishes an example of dimorphism or
even of polymorphism. All the broods which hatch out the same summer,
and there may be several, are of the same form (ajax), but many individuals
pass the winter in the chrysalis stage, some (marcellus) emerging early in
the spring, and some (lelamonides) appearing in late spring. The marcellus
form has “ tails” only about 2 inch long tipped with white, while the
telamonides is a little larger, with tails nearly an inch in length and
bordered on each side of their distal half with white; while ajar, the tvp-
ical form, is still larger and has longer “ tails.” i

The time of emerging seems to he the only influence controlling this
variation, since the offspring of each form, when maturing the same season,
produces ajax, when maturing early the following spring, produces marcel-
dus, and late the following spring, felamonides.

The larva of this species is light green, “ thickest in the thorax,” and with
transverse markings of black dots and lines and slender yellow stripes, be-
sides a yellow-edged, broad, black, velvety stripe on the thorax. It feeds
upon the papaw.

The tiger swallow-tail (Papil'io tur’nus), another common species, is also
dimorphic, In this instance the dimorphism is sexual; at least one of the
forms, glaucus, is represented only by the female.

1 Comstock, v0. 376.

LEPIDOPTERA 173

The cabbage butterflies (Pi’eris) (Fig. 143), of which there are three
species in the different sections of the United States, are the most, de-
structive to agricultural products of any of our butterflies. They have
three broods in the North and more in the South.

The wings of Pieris rape are a dirty white above, tinged with yellowish
in the female. The base and apex of the fore wings are blackish and the
female has two black dots on the fore wings; the male has but one. There
is a black spot on the anterior margin of the hind wing. In the male it
is indistinct. The larva is green, with a narrow greenish-yellow band upon
the back and a similar narrow broken “ stigmatal band.” It is covered
with fine short hairs. It feeds upon cabbage and other cruciferous plants.
It is exceedingly hard to combat, from the facts that there are so many

Fig. 143.—Cabbage-worm and butterfly (Pontia ra'pe): a, Female;
b, egg; c, worm eating on a cabbage leaf; d, suspended chrysalis; a, v, and
d slightly enlarged. (Chittenden, Cir. 60, B. Ent., U.S. D. A.)

broods and that the larva bores into the heart of the cabbage. The work
of extermination must necessarily be done before the cabbage begins to
head. Fresh pyrethrum and kerosene emulsion are helpful. It is hardly
safe to use Paris green except with quite young plants.

The gossamer winged butterflies (Lyceni'de) include three well-marked
groups which are commonly distinguished by their various colors as the
“blues,” “ the coppers,” and the “ hair-streaks.’”’” They are quite small
and delicate. The larve are slug-like. The “blues” are often seen
flitting about mud-puddles. Several species of the family are carnivorous.
One of them, the ‘“ harvester” (Fenis’eca tarquin'tus), common east of the
Mississippi River, is small, with the “upper surface of wings dark brown,
with a large irregular yellow patch on the disk of the fore wing and one of

174 BRANCH ARTHROPODA

the same color next the anal angle of the hind wing.” It is a friend to the
fruit grower, for its larva feeds upon woolly plant-lice like the apple-tree
aphis and the alder blight.

ORDER XII. HYMENOP’TERA

This order is represented by such familiar insects as the
bumble-bees, yellow-jackets, honey-bees, ants, wasps, ichneu-
mon flies, saw-flies, and gall-flies.

The mouth parts (Fig. 144) are adapted for biting or sucking,
the mandibles are short and fitted for biting, while the other

Three ocelli or simple eyes

BBY *
ae V7 Compound eves

i
i] \- Antenne

14
AS Clypeus (c).

TLubrum

Pulpifer or palpus bearer

Paraglosse or lateral lobes
of the tongue

Lingula or tongue attached at
the buse of the labium

Fig. 144.—Front view of the head of a bee. (Tenney.)

mouth parts, as the maxillw, labiwm, the maxillary and labial
palpi, are more or less modified into a proboscis for taking up
liquid food.

The wings are membranous and four in number. The
anterior pair is larger than the posterior. The student will
observe that the body and wings of Hymenoptera are shorter
than those of the dragon-fly order (Odonata).

The metamorphosis is complete. The larva: are maggot-like.

Habits.—They vary much in habits. Some are herbivorous
(saw-flies), some form galls, others are parasitic (ichneumon

HYMENOPTERA 175

flies). The stinging Hymenoptera, on account of their efficient
means of defense, are often mimicked (Fig. 132, p. 160)—the
bumble-bees by the hawk-moths, the hornets by two clear-
winged moths of the genus Sesia, the bee by the drone-fly
(Eristalis), the wasp by a common English beetle (Clytus
erictus), and the hornet by a Nicaraguan Hemiptera.

Saw-flies and ‘‘Horntails.”—Among the boring Hymenoptera are the
saw-flies, horntails, and gall-flies.

The saw-flies have a wide head and thorax, with a broad joining of the
base of the abdomen and thorax. The ovipositor consists of a pair of saws
with which slits are made in leaves or stems where the eggs are laid. The
larve look much like caterpillars, but may be distinguished by having from
twelve to sixteen pro-legs instead of ten. Most of these larve have “a
curious habit of curling the hind end of the body sidewise ” about a branch.
The rose-slug and currant-worm are familiar examples.

The currant-worm is the larva of
the saw-fly (Nem/atus ribe’sti). It is
a ‘criminal emigrant’’ and has left
a large army of descendants. The
female deposits her glossy white eggs
along the ribs of the first leaves of
currant and gooseberry bushes. In
ten days the little whitish larvee
hatch. They are voracious feeders
and will strip a bush of every leaf if
allowed to mature. When mature
they are green with a black head and
black spots and resemble caterpillars.
They pupate in brownish paper-like
cocoons, either attached to the bush
or hidden in the ground. There are
two broods in a season, provided the
first is not exterminated by a liberal Fig. 145.—Boring saw-fly or horn-
spraying with Paris green or hellebore. tail (Trt'mex coltim'ba).

If the spraying is thoroughly done

when the worms are quite small, they are easily poisoned, since, like all
insects with biting mouth parts, they swallow the poison with their food.
If any of the larve escape, the spraying must be repeated for the second
brood, or the bushes may be killed outright in one season. If the spraying
. done soon after the first brood hatches there is no danger of poisoning the
rut.

The horntails (Siric'id@) are so named because the posterior end of the
abdomen bears a spine or “‘horn.”” They differ from the saw-flies in hav-
ing an ovipositor “ which is composed of five long, slender pieces,” adapted
for boring instead of for sawing. There are several species in America.

The pigeon horntail (Tr?’mex coliim’ba) (Fig. 145) has a cylindric body
about } inch in diameter. It is 1} inches long, with rusty red thorax and
black abdomen, with yellow bands and spots on the sides, a yellow “‘ horn-
tail,’ and smoky transparent wings. The female pierces holes about 3 inch
deep in elm, oak, sycamore, or maple trees, bending the ovipositor at right

176 BRANCH ARTHROPODA

angles to the body in boring, and deposits her eggs, one in each hole.
When the larva hatch they do much injury by burrowing into the heart-
wood, where they feed, grow, and finally form cocoons of silk and fine bits
of wood. The winged adult gnaws its way out through the bark. The
ichncumon fly Thalessa is parasitic upon Tremez.

The gall-flies (Cynip'wle) live in closed galls during the larval state, and
the full-grown larva cither makes a hole and emerges and pupates in the
ground, or it pupates in the gall and the adult makes a hole through which
it emerges. The adult female pierces a hole in the tissue of the leaf with
her sharp-pointed ovipositor which is composed of “ several needle-like
or awl-like picces.”” In the incision thus made she deposits one or more
eggs. When the larva hatches an abnormal growth of tissue begins to
form about it, caused, perhaps, from some irritating excretions, or from
the physical irritation caused by the pressure of the irritating body. The
tiny, footless, white, maggot-like larva feeds, probably through the skin,
on the sap of the growing gall. When the gall dies, which is usually about
the time the -arva is grown, it dries and hardens and forms a protecting case
in which the larva (or larvee) pupates, and from which it emerges as a tiny
gall-fly in the first or second spring following.

But once of the strange things about these gall-flies is that, in some cases,
the successive generations of the same species are not of the same form.
The adult flies of one generation, which consists exclusively of females, lay
their eggs upon a certain host-plant, but the resulting individuals are not
at all like their mothers. This generation includes individuals of both
sexes which have developed from ‘ unfertilized eggs,” or parthenogenetic-
ally. The females of this generation lay their eggs upon a different host-
plant, develop very differently shaped galls from those in which they
grew up, but, like those of their grandparents, and the resulting individuals
are like their own grandparents. Not all gall-flics show this allernation of
gencration, some species appear always in the same form, but, strange to
say, they are usually represented only by females. Although there are
two hundred species of gall-flies, each species infests a special part, leaf,
branch, or root of one or more particular species of plants. The gall pro-
duced by each species of insect is of a definite form. This is a remarkable
manifestation of instinct. ‘It is impossible that. intelligence or memory
can be of any use in guiding the Cynipide; no Cynips ever secs its young,
none ever pricks buds a second season, or lives to know the results that fol-
low the act. Natural sclection alone has preserved an impulse which is
released by seasonally recurring feclings, sights, or smells and by the simul-
taneous ripening of the eggs within the fly. These set the whole physiologic
apparatus in motion and secure the insertion of eggs at the right time and in
the right. place.’

The Guest Gall-flies (In’quilines) —There are many gall-flies which do
not themselves form galls, but which lay their eggs in the galls formed by
others. The larve feed and develop here, but do not materially disturb
the rightful owners.

Parasitic hymenoptera (Jchnewmon'ida) are of great economic interest
(Fig. 146). Most. of them live within the bodies of their victims during the
larval stage, the egg being laid either within or upon the body of the host.
In the latter case the larva bores its way into the body and feeds upon the
blood, so that the host is not killed until the larva is grown. Each species

1 Stratton,

HYMENOPTERA 177

of ichneumon flics has its special host, the majority of them being cater-
pillars. The largest insect of this fumily belongs to genus Thalessa.

Thales’sa luna’tor has a body 24 inches long and the insect measures
nearly 10 inches from the tips of the antenna to the end of the ovipositor,
and is parasitic upon the larva of Tremer columba. The ichneumon fly
bores a hole with its flexible ovipositor, which is 6 inches long, into the tree
infested by Tremex, and deposits its eggs in the burrow of the Tremez larva.
When the ichneumon larva hatches, it creeps along the burrow until it
reaches its victim, the horntail larva,
to which it attaches itself and feeds
upon its juices. Sometimes the female
ichneumon fly gets her ovipositor fast
in the wood and it holds her a prisoner
until death.

Other important, though usually
small, parasitic Hymenoptera are the
braconids, the ensign-flies, and the
chalcid-flies. While the larve of para-
sitic Hymenoptera are degenerate in the
same way as the footless, eyeless, an-
tenneless maggots of house-flies, they
are not more so. Their parasitic habit
has led to no such extraordinary struc-
tural specialization through degenera-
tive loss, or reduction of parts as is the
usual condition in other parasites. The
adult is active and well developed.

The Stinging Hymenoptera.—The fe- Fig. 146.—Pimpla in the act
males and sterile workers, where there of ovipositing on cocoon of tent
are such, have the ovipositor developed caterpillar. Somewhat enlarged.
into an organ of defense, the sting. (After Fiske.)

Females may be distinguished from the
males by having six segments in the abdomen instead of seven. The
group includes ants, wasps, and bees.

Ants live in all lands and in very various conditions and occupations.
All of the 2500 or more species live in communities, and division of labor
among kinds of individuals and, consequently, differentiation of structure,
are highly developed. Ants are easily recognized by the form of the body,
but they are distinguished from other insects by the character of the first
one or two segments of the abdomen. These are expanded dorsally into a
“ lens-shaped scale or knot,’’ which varies in form and serves as a peduncle
to the rest of the abdomen.

The ants’ nests or formicaries are composed of irregular rooms and gal-
leries which may be mostly underground, or have a large portion above
ground, as a mound or ant-hill, or may be tunnelled out in the wood of de-
cayed trees. ‘‘ In the tropics,” says Comstock, ‘ a greater variety of these
structures occur than in our country. . . . One colony of one species
has been known to have two hundred mounds covering several hundred
square yards. Ants are also very good road makers, sometimes making
clean beaten paths or working out covered ways under rubbish.”

There are always three classes of ants (Fig. 147) in a community, winged
males and females, and wingless workers, sometimes also the soldiers and
wingless, but fertile males and females. The winged males and females at

12

178 BRANCH ARTHROPODA

maturity issue simultaneously from the nest and from neighboring nests,
so that the air will be filled with thousands of ants swarming about in their
mating flight. After this the males soon die, and the females which escape
from birds and other animals tear off their wings and go in search of a suit-
able nesting place. Sometimes the queen starts the new colony alone,
while in other species the workers find and adopt a queen and form a new
colony.

Inside the nest large numbers of very small eggs are laid in “ little piles
heaped together in various rooms and sometimes moved about by the
workers.” The Jarvie are small, white, footless, helpless grubs, which are
fed by the workers with regurgitated food or with chewed insects, or with
dry seeds and vegetable matter from the granary where they have been
stored. Most species spin cocoons in which to pupate—the white oval
bodies seen carried away by the ants when the nest is disturbed. The adults

Fig. 147—The pavement ant (Tctramorium cespilum): a, Winged
female; b, same without wings; c, male; ¢, worker; ¢, larva of female; f,
head of same; g, pupa of same; all enlarged. (Marlatt, Bull. U.S. Dept.
of Agriculture.)

are unable to escape from these cocoons unaided by the workers. The
workers are undeveloped females or females which seldom Iny eggs, and if
they do, these eggs always develop into males. These workers not only
feed the colony, but do all the work, building the nests and defending them
against enemies, even by war if necessary.

There may be from one to thirty queens, though in small colonies there is
usually but one. As these queens grow old, the workers seek young queens
at the swarming period and bring them into the nest. Ants, except the
males, which are short lived, are known to live longer than most. social
insects. Lubbock says he was able to recognize worker ants at Ieast seven
years old, and one queen died when over thirteen years old and another lived
more than fourteen yerrs.?

1 Comstock.
? Lubbock, ‘Senses, Instincts, and Intelligence of Ants,” p. 233.

HYMENOPTERA 179

Although ants are general feeders upon animal substances and fruit
juices, they arc very fond of sweet substances like the ‘‘ honey-dew ”
given off by aphids when stroked by the ants’ antenne. In return for
this choice food the ants shelter the aphid eggs in their nests through the
winter and carry the young plant-lice to tender plants in the spring. When
for any cause these plants become unsafe or unfit for the food of the aphids,
the ants will carry them to other plants. If ants are seen running up and
down the stem of some favorite plant, one may know, unless there is a
sweet substance exuding from bark or flower, that they are “ pasturing their
cows ” upon the juices of tender shoots and newly forming buds. A little
close looking will reveal myriads of tiny plant-lice on the under side or in
the axles of the leaves. Spraying with a little dilute commercial nicotin
will rid the plants of both ants and plant-lice. Arsenic poisons cannot
affect aphids or other insects having sucking mouth parts, since their food
consists of the internal juices of plants which cannot be reached by the
poison.

There are many other insects which live in the nests of ants. In 1900
Wasmann recorded 1177 insects living in the nests of ants (myrmecoph-
ilous insects), many of which were beetles. Most of these insects live
a commensal life with the ants. It is not known of what advantage they
are to their hosts. The guests, however, obtain shelter, food, moderate
temperature, defense against enemies, and even, in the case of migratory
ants, transportation. In the case of some small beetles, however, there is
true symbiosis with the ants, the beetles secreting a sweet substance which
the ants eat greedily, and in return the ants “clean, care for, and feed by
regurgitation” the degenerate little beetles.

The ants furnish an example of a perfect communistic society. There is
no special care or favoritism for wife or child or friend, but a common love
for the whole community. “Eiverything is done for the good of the whole
and nothing for the individual. The state makes wars, provides food for
all, cares for the children, owns all the property, the fate of each one is
determined by the accident of birth, and each takes up its work without a
murmur. . . . This perfect commune has developed courage, patriotism,
loyalty, and never-failing industry, but also war, pillage, slavery, and an
utter disregard of the rights of other communities and individuals.’”!

Most of the ants which have been described in this country can be placed
in one of three families: (1) Formic‘ide, in which is found the interesting
carpenter ant (Campon’otus pennsylva’nicus), one of the largest of our com-
mon black ants. _ It builds its nest in the dead interior wood of living trees
and wooden buildings. Here also is the mound-building ant (For’mica ex-
sectot'des), with its rust-red head and thorax and black abdomen and legs.
Its ant-hills are from 5 to 10 feet in diameter. One of the most interest-
ing of the family is the slave-making ant (Formica diffic’ilis). In this species
the workers work with the slaves, but Polyer’gus rufes’cens, a European
species, depends upon the slaves to do all the work for the community.
The adults are not taken captive, but in war and pillaging the larve and
pup are some of them eaten and some of them carried home, where, if not
eaten, they develop into the adult workers, and instinctively go to work for
their hosts, building nests, bringing food, and nursing the young. In some
species this is carried on to such an extent that the hosts become unfitted for
any work but that of warfare, and are dependent solely upon the slaves for
shelter, food, and all the necessary work of the community. Thus their

1 Comstock, p. 634.

180 BRANCH ARTHROPODA

slave making has reacted upon themselves, rendering them unable to help
themselves. It is a law in all animal life that dependence upon others
renders one more dependent, while dependence upon self develops inde-
pendent powers.

The corn-louse ant (Las’ius brun’neus) is the common small brown ant of
our pastures, woods, and meadows. It is of especial economic interest on
account of the care it bestows on the corn-root plant-louse. The eggs of
the plant-louse are laid in the ant’s nest, where they are sheltered during the
winter. In the spring the ants place the young aphids upon the roots of
certain knot-weeds until the corn has germinated and then remove them to
the corn-roots. These aphids do great damage in the Middle West. (See

. 144.)
: (2) Poner’id@ is the smallest family in number of species, there being but
about twenty-five known in this country, and the least specialized, that is,
the least differentiated into castes. The queen and workers are stingers.
Their nests are made under stones or logs.

(3) Myrmic'ide.—This family is characterized by two segments in the
peduncle. Usually the queen and workers have stings. The pupz are
naked. To this family belongs the tiny ‘‘red ant’ (Monomo’rium phar ao'-
nis), which is in reality a light yellow, that is the torment of housewives.

The agricultural ants (Pogonomyrmez) live in the southern and western
states. They, with the exception of one species, live in nests partly under
ground, covered with conspicuous mounds in open sunny places. They cut
away the grass immediately about the nest. It has been popularly believed
that they sow the seed for their food, but Wheeler says that they carry out
the débris, which consists of chaff and sprouting grain, and deposit it at the
edge of the cleared circle. The seeds often grow and do yield a harvest for
their next winter’s stores, though not intentionally planted.

Intelligence.—There is a great diversity of opinion among
scientists who have experimented with ants as to the ‘‘ mental-
ity ” of these insects. Bethe! and others hold to a purely me-
chanical or reflex theory, while Loeb, Wheeler, and others at-
tribute to them reflexes, instincts, and animal memory, and
Lubbock and Forel give them a considerable degree of intelli-
gence. Comstock says they ‘think.’”? Whether they are
governed by one or all of these attributes, it is surely probably
that the mechanical and chemical forces which affect the
nervous activities of the ants may also influence those of men,
and that if the same rigid experiments and final analyses were
applied to the various phases of man’s activitics, there would
result quite as many surprises as have accompanied the experi-
menting upon insects, indicating that many of his activities
are responses to mechanical stimuli, and yet no one doubts
that man possesscs intelligence. Whether the activities of ants

1 Kellogg, 544. 2 Comstock, 637.

HYMENOPTERA 181

are governed by reflex action, instincts, or intelligence (in a
limited degree, of course), or, what is more probable, by a cer-
tain combination of these, they certainly perform many won-
derful feats, considering the fact that they have but a single
set of tools, the mandibles. They use these to dig and tunnel,
to obtain food, and to carry and manipulate their food, to fight,
to carry tenderly their eggs and young, or to cut leaves and husks
and seeds. Though they have no voice, they are known to
eommunicate by means of touch through the agency of the
antenne. It is believed that they recognize friend or foe by
the odor.

The digger wasps (Spheci'na) are a group of closely allied families of
Hymenoptera. They may be distinguished from true wasps by the fact
that their wings lie flat above the body, and from bees by the adaptation of
their legs for digging and walking. They are all solitary. Each female
makes her own nest by burrowing in the ground or in wood, or by construct-
ing a tube of mud, or using one found already made. In this nest she places
certain insects which she has paralyzed but not killed, by stinging, lays an
egg, and seals up the cavity. When the larva hatches it feeds upon the food
thus provided for it by the mother. The parasitic forms lay the eggs upon
the paralyzed bodies of their hosts, and the guest-species lay them in the
nests of other wasps or bees, where the larvee feed upon the food prepared by
the host for its young.

Familiar examples of the digger wasps are the mud daubers (Pelope’us)
of our attics and eaves. It is thought that these wasps find their nests again,
after going in search of insects with which to ‘‘provision”’ their nests, by the
memory and recognition of localities, for they go from place to place, back
and forth in many curious zigzag or circular routes, but find their way back
to their nests readily.

The ‘‘tarantula-killer” (Pip’sis formd’sa), of the West and Southwest, is
a large solitary wasp which provisions its nest with the choicest of food, such
as tarantulas, though many a hard battle is necessary to procure them.
Sometimes the tarantula makes a meal of the wasp instead of becoming food
for its young.

The true wasps (Vespi/na) are characterized by the folding of their wings
lengthwise like a fan when at rest, by the kidney-shaped eyes, and by the
absence of bristles or spines from the legs.

One family (Humen’ide) of the true wasps leads a solitary life. One of
these (.Vono’bia quad’ridens) tunnels into wood and partitions off the
tunnel, making a cell for each larva.

Another species (Hu’menes frater’nus) is a thorough mason, making little
jug- or vase-shaped nests of clay or mud which it attaches to the stem of a
plant. It provisions it with caterpillars, often with canker-worms.

The social wasps (ves’pide) live in communities in spring, summer, and
autumn. The males and workers die in the autumn, and the females
(queens) hibernate through the winter under logs or stones or in crevices.
In the spring each queen starts a colony. She makes a small nest containing
a few brood-cells, in each of which she Jays an egg. The hatching larve

182 BRANCH ARTHROPODA

are fed by the queen with insects captured, killed, and somewhat masticated
by herself. In a few days the larve pupate in the cells and soon issue as
workers. These enlarge the nest, adding new brood cells, which the queen
fills with eggs, which, upon hatching, are fed by the workers. Thus, several
broods of workers are reared, and the nest is continually enlarged to make
room for the increasing family. Early in autumn a brood is hatched con-
taining males and females, which mate probably with individuals of other
communities, and at the approach of winter most of the colony dies, leaving
only a few hibernating queens.

The nest of the social wasp may be under ground, in which case it is made
of partially decayed wood, or it may be attached to bushes or trees or under

Fig. 148.—A hornet’s nest, showing two horizontal sections of comb, one
above the other, and the many layers of paper surrounding the nest. (Photo-
graphed from object.)

the eaves of buildings. This wood is formed into a pulp by being masticated
with saliva and chewed. In the genus Polis’lcs the nests consist of a single
cone and are not inclosed in an envelop, but in the genus Vespa, including
the yellow-jackcts and hornets, the nest (Tig. 148) consists of several hori-
zontal cones suspended one above the other, yet separated by a considerable
space from cach other, and the whole enveloped in a waterproof covering of
many thicknesses of wasp-made paper, the whole nest forming a globular
or cone-shaped ball. When the nest is tobe enlarged the wasps nibble away
the inner layers of the enveloping paste and add new lavers on the outside.

Yellow-jackets and Hornets (\espa).—In this genus the body of the
wasp is rather stout and short and the peduncle is very short. The color

HYMENOPTERA 183

is black, spotted, and banded with yellow, from which we are all glad to
take ‘ warning,” for the sting of a hornet is painful and the nest contains
thousands of individuals. The queens are larger than the workers. It
may be interesting to know that the males have no sting. They may
be further distinguished from the other forms by having seven segments
in the abdomen instead of six.

The social wasps do not store up food, but continually feed the young
throughout the larval stage, which lasts from eight to fifteen days, with
partially masticated insects. The adults ‘ feed upon insects or decompos-
ing animal substances (fish especially attracts them) and upon exposed
sweet substances, such as syrups and preserved fruits.”

Bees may be distinguished from all other Hymenoptera by their cen-
larged and flattened tarsal segments, which, except in the Jn’quilines, are
provided with an arrangement for carrying pollen. It is said that the
hairs (at least on the head and thorax) are branched or plumose, as revealed
by the microscope, while those of all other Hymenoptera are simple.

The nests of bees are always provided with pollen or honey, or both.
The larve when quite young are fed by a substance called ‘“ bee-jelly,”
yegurgitated by the nurse workers; for the bee colony, like those of other
Hymenoptera, consists of three forms: the workers, the males or drones,
and the female (queen).

The short-tongued bees (Anidren'ide) are all either solitary or grega-
rious, none social. Some of the mining bees, genus Andrena, are almost as
large as the honey-bee workers. In grassy fields they sink a perpendicular
shaft into the ground sometimes to the depth of a foot or more, which
branches off sidewise to the cells. Though each nest is solitary, the females
often build close together.

The smallest of our bees ( Halic’tus) burrows in sand-banks or cliffs.
Several females unite to ‘‘ make a burrow into the bank, after which each
female makes passages extending sidewise from this main burrow or
public corridor to her own cells. While Andre’na builds villages composed
of individual homes, Halictus makes cities composed of apartment houses.’’!

The long-tongued bees (A’pid@) have the lower lip highly specialized
for obtaining nectar from flowers. The basal segment of the labial palpus
is also elongated. Some of this family are solitary; others, guest-bees;
a few, social.

Among the solitary long-tongued bees is Megachi’le acu'ta, a carpenter
and leaf-cutter, which, if it does not find a convenient crevice or cavity
ready made, tunnels out a tubular cavity in wood and builds a thimble-
shaped nest at the bottom out of oblong pieces of leaves which it cuts out
for itself, and fills it with a paste of pollen and nectar. The egg is then
placed upon this food and the opening tightly plugged up with circular
pieces of leaves.

The little blue carpenter bee (Cerat'ina du’ pla) builds its nest in dead twigs
of sumach or in the hollows of other plants. The female fills the bottom of
the nest with pollen, lays an egg upon it, and makes a partition above the
egg out of pith chips made in forming the tunnel. She continues making
these cells until the tunnel is nearly full, then she rests in the space above the
last. cell and waits until the young are grown. When the first one is
ready to emerge, it tears down the partition above it and waits till each one
has performed the same process, when they are led by the mother into the
open air. Comstock says it is the only instance he knows of a solitary

1 Comstock, p. 666.

184 BRANCH ARTHROPODA

bee watching her nest. The old nest is cleaned out by the whole family
and used again by one of them. ;

The guest-bees (/1quilines) infest the nests of both solitary and social
bees, sometimes being unwelcome guests. They have, of course, no
worker forms, only males and females, since work is not necessary when
they can live off the bounty of others. Those infesting the nests of
solitary bees steal into the nest before it is completed and lay their eggs,
which hatch before those of the host, and devour the food intended for the
young of the rightful owner. Strangely enough, the Inquilines (sth 'yrus)
seem to be welcome, for if they were not the bumble-bees surely would
drive them out, for they certainly could. The female lays her eggs in a
bumble-bee’s nest, and when the larva hatch they are cared for by the bum-
ble-bees as if they belonged to them. Sometimes the guests very closely
resemble their hosts in size and color, but in other cases they are marked
very differently. The males resemble the bumble-bees so closely in ap-
pearance and structure that it is difficult to determine whether they belong
to Psithyrus or Bombus, but the females are easily distinguished, for the
pollen-basket of the hind legs has been lost through disuse. There are
no workers among the Psi/hyrus, and if for uny reason the supply of the
host should fail them, the guests would starve, for they are so degencrate as
to actually be unable to work. Kellogg says these guest-bees “ure like
bumble-bees in so many structural details unnecessary for deception (mim-
icry) that they must be looked on as a degenerate offshoot from the Bom'-
bide,” that is, as degencrate bumble-bees.

The social bees, which are native, belong to the genus Bombus. The
bumble-bees, like the ants, live in communities having three kinds of in-
dividuals: males, females, and workers. In early spring each queen which
has survived the winter by hibernating seeks some unoccupied mole’s nest
or mouse’s nest or digs a cavity in the ground for her nest. In this she
deposits a ball-shaped mixture of pollen and honey and lays a few eggs,
not over twenty, upon it. Then she brings another supply of food and de-
posits more eggs. When the first larve hatch they feed upon the food
provided, and when grown each spins a silken cocoon and pupates. These
all form worker bees, which enlarge the nest and provide more food. The
queen lays more eggs and the workers now enclose the larve in waxen
cells. A few cells also are filled with pollen or with honey. The nest
may become as large as one’s head and is covered loosely with bits of vege-
tation. It usually has two or more openings. ‘ Later in the summer males
and females appear, and it can be said to the eredit of the bumble-bee queens
that they are not jealous, but allow the young queens to live with them in
thenest.”” In early winter all bumble-bees perish except the voung queens,
which hibernate in some crack or crevice. There are more than fifty species
of bumble-bees (Bombus) in the United States. They differ in size and in
the arrangement of the black and yellow color-patterns.

The honey bee is a native of Europe, but has been domesticated the
world over. “It has been known and cared for by men for centuries.
There are two genera: (1) Mclipona, which has the sting blunted and ap-
parently never used as a weapon, lives in the tropics and consists of numer-
ous species which have been little studied. (2) .tpis has but few species,
one of which is our common hive bee.

The community consists normally of one queen, from less than a hundred
to several hundred males, and from about. 10,000 workers in winter to 50,000
insummer. The queen (Tig. 149, A) may be known by her long slender ab-

HYMENOPTERA 185

domen and by the absence of wax plates, planta, and pollen baskets. The
queen is hatched from « fertilized egg in a large cylindric, vertical cell
(Fig. 149, 6-10), and fed almost wholly upon bee-jelly regurgitated by the
nurse workers. Here, at least, is one strong example of the influence of
environment during development, for it has been proved that there is no
difference between the egg from which the queen is developed and the one
which develops into the worker.

The workers (Fig. 149, A), which are the bees we commonly see, are smaller
than the queens and males. They are hatched in hexagonal, horizontal

Fig. 149.—Hive bees and comb (after Schmeil). A, Worker; K, queen;
D, drone; 1, worker with cells filled with honey and covered; 2, cells con-
taining eggs, larve, and pups; 3, cells containing pollen; 4, below 4 are
regular cells; 5, drone cells; 6-10, queen cells.

cells, and fed, like the males, with honey and bee-bread. ‘‘ Workers have
wax plates under the abdominal segments and pollen baskets on the outer
surface of the hind tibie.”’

The males, or drones (Fig. 149, D), have a hairy thorax and a heavy,
broad, blunt body, and, like the queen, lack the special structures of the
workers. They are hatched in the larger, hexagonal, horizontal cells from
“unfertilized ”’ eggs. After the swarming scason is over, the males are
driven out of the hive or stung to death by the workers.

When a community becomes too large, the workers prepare a ‘t queen-
cell” and develop a queen by process of special feeding and care, or, it

186 BRANCH ARTHROPODA

may be, several queens are so developed. When these young queens emerge,
the old queens at once enter into battle with them. All new queens are
killed but one, which the workers guard. The old queen leaves the hive
accompanied by a swarm of workers and founds a new colony. The work-
ers at once begin to secrete wax by gorging themselves with honey and then
together “ hang quietly in a curtain-like mass, the upper bees clinging to
the roof of the hive and the lower ones to the bees above them. After
about twenty-four hours there appear little flakes of wax that are forced
out from openings between the ventral abdominal segments, called wax-
pockets. These wax scales continue to increase in area and soon pro-
ject beyond the margin, and either fall off or are plucked off by other workers
or by the wax-producing worker itself.’””! Other workers construct it into
comb, the trowel-like mandibles pressing it into hexagonal cells. Each
comb consists of a double layer of cclls separated by a common partition.
New wax is used in forming cells for storing honey, but old wax or wax
mixed with pollen may be used for brood-cells. The workers also carry
“ propolis,” a sticky, gummy substance with which they at once stop the
chinks of their hive. They carry water also to the thirsty larva. By
steadily and rapidly vibrating their wings a set of workers stationed at the
exit or scattered about the floor form currents of air, thus ventilating the
hive. Another set acts as scavengers and carry off all dead and decaying
débris from the floor and walls. Still another set guards the entrance from
intruders, such as neighboring bees, yellow-jackets, and bee-moths. For
guarding against the minute bee-licc and bacterial diseases the help of man,
“ the bee-keeper,” is needed. Kellogg gives an observation hive and how
to make it, which would be well worth trying. For after you have studied
carefully these, shall I say, intelligent little creatures you will find it, indeed,
difficult to decide which of their actions are reflex, instinctive, or intelligent,
or which are all of these combined.

Classification.—

Class I. Crusta’cea.
Sub-class Hn/tomos’traca.

Order I. Phyllop’oda. Brine shrimp. Daphnia.
Order II. Ostrac’oda. Cypris.

Order III. Copep’oda. Cyclops.

Order IV. Cirripe’dia. Barnacles.

Sub-class Afal’/acos'traca.
Order I. Phyllocar’ida. Nebalia.

Order II. Decap’oda. Crayfish, lobsters, crabs.

Order Il. Arthros’traca. Gammarus. — Pill-bug.
Class IL. Arach’nida.

Order I. Scorpion’ida. Scorpions.

Order II. Phalangi’da. “Daddy-long-legs.”

Order Ill. Arane’ida. Spiders.

Order IV. Xiphosu’ra. Limulus or Horshoe Crab.

1 Kellogg, p. 526.

HYMENOPTERA 187

Class III. Afyriap’oda.

Order I. Chilop’oda. Centipedes.
Order II. Diplop’oda. Millipeds.
Class IV. Insec’ta.

Order I. Ap’tera,or Thys- “Fish-moth” and “spring
anu’ra. tails.”

Order IJ. Ephemer’ida. May-flies.

Order Ill. Plectop’tera. Stone-flies.

Order IV. Odona’ta. Dragon-flies.

Order V. Isop’tera. Termites.

Order VI. Corroden’ita. ‘“‘Book-lice.”’

Order VII. Malloph’aga. “Bird-lice.”’

Order VIII. Euplexop’tera. Earwigs.

Order IX. Orthop’tera. Grasshopper, katiy-did.

Order X. Physop’oda. Thrips.

Order XI. Hemip’tera. Chinch-bug, plant lice,

and cicada.

Order XII. Neurop’tera. Aphis-lion, ant-lion.

Order XIII. Mecop’tera. Scorpion-flies.

Order XIV. Trichop’tera. Caddice flies.

Order XV. Lepidop’tera. Butterflies, moths.

Order XVI. Coleop’tera. Beetles.

Order XVII. Dip’tera. Flies.

Order XVIII. Siphonap’tera. Fleas.

Order XIX. Hymenop’tera. Ants, wasps, bees.

BRANCH CHORDATA

Branco Chordata comprises many of our best-known. and
valued animals.

Atl 1m rea ues
Fis: — SalaMANpeR: TORTOISE. CH(GK:
Fig. 150.—A scries of embryos at three comparable and progressive stages
of development (marked I, H, III), representing each of the classes of
vertebrated animals below the Mammalia. (After Hickel.)
188

BRANCH CHORDATA 189

Characteristics.—They all have (1) Gill-slits in their embry-

TIL I Tm Tr
Hog. Caur. RABBIT. MAN.
Fig. 151.—A series of embryos at three comparable and _ progressive

stages of development (marked I, II, III), representing four different di-
visions of the class Mammalia. (After Hackel.)

onic life or they may be permanent; (2) a notochord; (8) a nerve
chord or nervous system dorsal to the notochord. The noto-

190 BRANCH CHORDATA

chord is a smooth, elastic rod typically developed from the endo-
derm, extending along the median line between the alimentary
tube and the central nervous system. It is encased in a tough
sheath or membrane and “‘forms an elastic supporting structure.”

2) ys

Fig. 152.—Ideal primitive vertebrate, seen from the left side: na, Nose;
au, eye; md, mouth; g, ear; ks, gill openings; x, notochord; mr, spinal tube;
kg, gill-vessels; #, gill-intestine; Az, heart; ms, muscles; ma, stomach;
v, intestinal vein; c, body cavity; a, aorta; /, liver; d, small intestine; e,
ovary; A, testes; », kidney-canal; af, anus; /h, true or leather skin; oh,
outer skin (epidermis); f, skin-fold, acting as a fin. (After Hackel.)

In the higher forms the notochord is replaced by a segmented
cartilaginous or bony vertebral column.

These three characteristics may not be easily recognized by
the beginner as he looks at the worm-like Bal/anoglos’sus, the

Fig. 153.—The same in transverse section through the ovaries; lettering as
in the preceding figure. (After Hiickel.)

sac-like sea-squirt, or the small fish-like or worm-like Am’phiox’ us
or Lance’let, but, passing by these low forms to the fishes, frogs,
reptiles, birds, and mammals, one readily finds that the body has
two cavities instead of one, as in the invertebrates.

ADELOCHORDA 191

Neural Cavity.—The upper or neural cavity contains the brain
and the spinal cord.

Hemal Cavity.—Below the vertebral column with its neural
cavity is the large cavity of the body, the hemal cavity, which
contains the heart, lungs, digestive organs, and other viscera.

Skeleton.—Most of these higher forms have an internal bony
skeleton or a cartilaginous one, as in some fishes. The vertebral
column, or backbone, is composed of a varying number of bones,
each called a vertebra, hence the branch is named Vertebrata,
or, if named from the notochord, Chordata.

Divisions of the branch are usually
made to distinguish the primitive groups
(Fig. 152) or Protovertebrates, from the
true Vertebrates.

The Protovertebrates consist of three
separate groups or sub-phyla, not closely
related to each other, but each, in a
primitive way, is entitled to relationship
with the Chordata or Vertebrata.

SUB-PHYLUM AND CLASS I.
ADELOCHORDA

The Balanoglossus is the principal
genus of this group, though two deep-
sea forms (Rhabdoplew’ra and Ceph’alo-
dis’cus) have a notochord, and the latter
has a pair of gill-slits, but in other ways Fig. 154 Balano-

: glossus: p, Proboscis;
they are like the polyzoans. The Bal- ¢ “collar”; gs, gill-
anoglossus (Fig. 154) is a small marine slits; enlarged. (From
chordate. Its surface is ciliated. It _is eee ae
from 1 to 4 or 5 inches in length, and, by — Co., Publishers.)
means of its proboscis, burrows in the
mud along the seashore. A study of the animal or of a good
figure will show that it has (1) a dorsal nerve cord, (2) a
notochord, and (3) gill-slits.

Body Regions.—The Balanoglossus is divided into three
body regions: the proboscis, a club-shaped hollow anterior por-
tion opening exteriorly by a single pore; back of the proboscis

192 BRANCH CHORDATA

is the collar, opening by two spores into the first gill-slit; the re-
mainder constitutes the flattened but nearly cylindric trunk.
There is no segmentation of the body. By alternately contract-
ing and dilating the proboscis and the collar the Balanoglossus
can burrow in the mud.

Gill-slits —On the dorsal surface of the anterior portion (the
branchial region) of the trunk is a double row of gill-slits which
increase in number throughout life.

Digestive System.—The mouth is situated ventrally at the base
of the proboscis just within the collar, and fromit the alimentary
canal extends to the posterior extremity of the body. ‘‘Into the
dorsal half of the anterior portion of the alimentary canal open
the internal gill openings.”’ The hepatic ceca bulge out in ex-
ternal prominences in the middle part of the canal. The
anal opening is at the posterior end of the body.

The notochord, ‘‘a blind tube surrounded by a tough mem-
brane, extends from the pharynx into the proboscis.”’ There are
dorsal and ventral nerve strands connected by nerves in the
collar.

A dorsal blood-vessel lies above the notochord.

The larve of some species so much resembles certain echino-
derms that the Balanoglossus was formerly placed with that
branch.

SUB-PHYLUM AND CLASS II. UROCHOR’DA OR
TUNICATA

This degenerate group is represented hy minute animals a few
centimeters long and by some measuring several feet in length.
They are found singly or in string-like colonies which have been
developed from a solitary individual by budding, the two forms
thus giving rise to alternation of generations. Multiplication
is both sexual and asexual. They are hermaphroditic, but cross-
fertilization occurs. They are marine and most of them are
pelagic.

The most common forms, the ‘‘sea-squirts” or ascidians (Fig.
155), are surrounded by a tough elastic bag, one end of which is
attached to stones. At the other end is a large round oral
aperture, for the inlet of water carrying food and air, and near it,

UROCHORDA OR TUNICATA 193

on one side, is the atrial aperture, for the exit of the current.
Sea-squirts are destitute of head and limbs. The ventral heart
enclosed in a pericardium is situated between the gill region and
the stomach. This heart has the peculiarity of changing the
direction of its contractions. When the blood has been driven
to the gills for a while it rests a little, and then forces the blood
in the opposite direction.

Fig. 155.—Diagram of the growth of a sea-squirt or ascidian: A, a, young
free-swimming stage; a@?, intermediate stage just before becoming fixed.
B, b, Full-grown sea-squirt, rooted to the sea bottom and incapable of
movement: m, mouth; e, hollow brain with eye; g, gill-slits; h, heart; r, rod
of gristle in free-swimming form; nv, nerve cord in same; ¢, tail in process
of absorption in intermediate form. (After Haddon.) (From Baskett,
“ The Story of the Fishes,” D. Appleton and Co., Publishers.)

The ‘‘sea-squirts” were formerly called ‘“Tunicates,” until a
study of their larval stage showed them to have vertebrate char-
acteristics. The larva has a slender finned tail containing a
notochord and a nerve cord. They furnish an example of retro-
grade development. They are free for a few hours, then be-
come fixed and lose the notochord and nearly all traces of their
vertebrate characteristics which promised a higher develop-
ment.

194

BRANCH CHORDATA

SUB-PHYLUM AND CLASS III. ACRA’NIA OR AMPHIOXUS

«2.

Li

WIT LE

re TT
Z KGa

This is a small fish-like chordate 2 or
3 inches in length.

Its shape is one found for the first time,
that of narrow ventral and dorsal sur-
faces and deep lateral surfaces. It is
pointed at both ends. It falls on its side
when not in motion.

It is marine and lies buried in the
clean sand along warm seacoasts, with
its ciliated lips protruding. The currents
produced by the cilia bring fresh water
with its oxygen to the gills. Small organ-
isms are also thus furnished for food.

The Am’phiox’us (Fig. 156) has no
limbs, no skull, no well-differentiated
brain, and no heart, but it has a noto-
chord (a smooth cylindric rod lying above
the alimentary tube), a nerve cord dorsal
to the notochord, numerous gill-slits,
and an alimentary tube. The sexes are
separate.

The alimentary tube is a straight tube
consisting of mouth, pharynx, and in-
testine. On the right side of the pharynx
is a blind pouch, the so-called liver.

The circulatory system consists of a dor-
sal arterial trunk and a ventral venous
trunk connected by lateral arches. The
blood is colorless.

Fig. 156.—A mphior'us lanceola'tus : a, Anus;
au, eye; b, ventral muscles; c, body cavity; ch,
notochord; d, intestine; do and du, dorsal and
ventral walls of intestine; f, fin-seam; h, skin;
k, gills; ka, gill-artery; /b, liver; lv, liver-vein;
m', brain vesicle; mm, spinal marrow; mg,
stomach; 0, mouth; p, ventral pore; r, dorsal

muscle; s, tail fin; ¢, t, aorta; 1, intestinal vein; x, boundary between gill
intestine and stomach intestine; y, hypobranchial groove. (After Hackel.)

CYCLOSTOMATA 195

Locomotion —The Amphioxus has a median dorsal fin which
extends over the tail both dorsally and ventrally. The tail,
that portion of the body posterior to the alimentary tube and
filled with muscle, is the chief organ of locomotion. It is noc-
turnal, swimming about at night, but quickly returns to its
burrow if disturbed. It can burrow in the sand with either head
or tail.

Nervous System.—A simple dorsal nerve lies above the noto-
chord. It does not reach entirely to the front of the body. Its
anterior tip is called the cerebral vesicle, in which there is an
eye-spot. There is also possibly an olfactory organ consisting
of a simple pit reaching from the skin down into the anterior
tip of the nerve cord.

SUB-PHYLUM IV. CRANIA’TA OR VERTEBRA’TA

These are chordates having a brain or skull. The group
includes fishes, amphibians, reptiles, birds, and mammals.
The body is usually elongated and more or less cylindric.
The mouth is situated anteriorly. Ventrally and near it, ex-
cept in Cyclostom’ata, are the paired nostrils. Situated in
the head there are alsoa pair of eyes and a pair of ears,
though the ears are not always external. Gill-slits are
never more than seven in number, and partially or alto-
gether disappear in the adult air-breathing forms. There
are one or two pairs of jointed limbs, but in some cases they
are rudimentary or wanting.

CLASS I. CY’CLOSTOM’ATA

The animals of this class inhabit both fresh and salt water.
They have no lower jaw. The mouth is suctorial, the skull
cartilaginous, the notochord persistent, and the teeth horny.
The neural arches are rudimentary. There are no limbs or
scales and no paired fins; but unpaired dorsal and caudal
ones are present. The class includes the lampreys (Fig.
157) or “lamprey-eels” and the hag-fishes. The skin is

196 BRANCH CHORDATA

slimy and very smooth. The gills of the lampreys open into a
respiratory tube lying below the gullet.

Vig. 157.—Lamprey (Pefrumy'zon mari’nus). (After Goode.)

They are parasitic on fishes and also devour crustaceans. The
slimy eels bore into fishes and eat the flesh.

CLASS II. PIS’CES

To this class belong the true fishes, common examples of
which are the sunfish, perch, salmon, catfish, carp, and trout.
They are aquatic, gill-bearing, poikilothermal, usually scaly,
bilaterally symmetric finned chordates.

Shape.—The typical fish is wedge shaped (Fig. 158) at both
ends, so that it can pass rapidly through the water. The head
is large and pointed, with the viscera situated near it, while the
trunk is long and tapering, for the attachment of muscles to flex
the tail in locomotion. Usually the body is more or less flat-
tened from side to side, though it may he quite cylindric, as in
the eel, or flattened dorsoventrally, as in the adult flounder, or
the body may be long and slender, as in the pipe-fish and ribbon-
fish. The shape conforms largely to the habits and habitat.
The fishes having the under side flattened usually swim near or
rest upon the bottom at some time, as our catfish, but the broad
forms, flattened above and below, like the skates and flounders,
live upon the bottom and are not built for speed. The “flat
fishes” in early life have the position common to most fishes, but
in adult life the dorsoventral plane becomes horizontal instead
of vertical, the eye lies upon the upper side, and the color of the
upper side becomes dark like the dorsal side of most fishes, and
the under side light like the ventral side.

PISCES 197

Size and Number.—Fishes vary in length from an inch or less
to 30 or 40 feet. Kellogg says there are about ‘15,000 species
of fishes known, of which 3000 species live in North America.”
Is it any wonder they vary in size, color, and habits? They are
the best adapted of all vertebrates for an aquatic life.

Covering.—The epidermis consists of many layers of proto-
plasmic cells with a very thin cuticle. The secretion of mucus
by the great numbers of ‘‘slime-cells” of the epidermis gives to
fishes their slippery skin. The epidermis contains also pigment
cells. The dermis consists of numerous layers of connective

Fig. 158.—Figure of a whitefish, showing the location of parts usually
referred to in descriptions: 1, Dorsal fin; 2, adipose fin; 3, caudal fin; 4,
anal fin; 5, pectoral fin; 6, ventral fin; 7, lower jaw, or mandible; 8, upper
jaw, or maxillary; Sa, supplemental maxillary; 9, opercle; 10, branchioste-
gals; 11, caudal peduncle; 12, lateral line; 13, series of crosswise scales usually
counted; 14, snout; 15, eye; 16, head; 17, depth; 18, base of caudal; 19, dis-
tance from snout to nape or occiput. (Report U.S. F. C., 1894.)

tissue and furnishes the dermal or exoskeleton or scales which are
usually embedded in pockets of the dermis.

In many fishes the scales overlap each other. In the brown
trout, for example, the greater portion of each scale lies under
the one anterior to it, and the remainder, a small triangular por-
tion, is covered by the epidermis only. The scales sometimes
receive a layer of enamel or vitrodentin from the epidermis.
(1) The placord scales are rhombic, plate-like bodies often bearing
a spine covered with vitrodentin. These scales are placed close
together, but do not overlap. (2) The ganoid scales also are

198 BRANCH CHORDATA

generally “rhomboid and arranged like parquetry.” They are
covered with a thick coating of vitrodentin which gives. an
iridescent effect, and are often closely articulated into a coat of
armor. (3) The cycloid scales are closely related. They are
placed loosely in the pockets and arranged in rows. In over-
lapping, one scale covers parts of two scales posterior to it. The
middle part of the scale is surrounded by concentric lines from
which proceed radiating lines. (4) The ctenoid scales (see Fig.
174) have the posterior edges truncate and the free margin
toothed. The scales are often striated or polished, and this
gives rise to various colors, especially the iridescent gleam on
the sides of the fish.

Color.—The color in general harmonizes with its environment.
Most of the fresh-water fishes are dark colored (olive or greenish)
above and whitish below, so that to the enemies from above,
as fish-eating birds, the form appears indistinct in the water, and
to the enemies below they look white like the light. Many are
variously dotted or striped with lighter or darker colors, thus
simulating the lights and shadows among the weeds and grasses.
The scales reflect all the hues and tints of the rainbow, causing
the fishes to rival the birds in beauty. The males of some species
put on brighter colors at the spawning season. Some species
have the power of changing color at once to meet the surround-
ings, as the pipe-fishes, some sticklebacks, the plaice, and the little
Oligocottus snydert, of Monterey Bay, California. Many others
change the colors more gradually. Recent experiments upon
fishes in aquaria have shown that if the light be thrown from
below and cut off from above, the upper part grows light colored
and the lower part dark colored. This would seem to show that
the colors are due to the action of light, but while many fishes
in caves are colorless, it is said that those in the black depths
of the ocean may be either pearly white or black; so the question
is yet unsolved. Many deep-sea forms are phosphorescent.

Some fishes have special protective resemblance, as the leaf-
finned sea-horse, the pipe-fish, and some angler-fishes, the pos-
terior fins of which are bedecked with fringes ‘‘that exactly
mimic seaweed.” The mouse-fish, or Sargassum, is colored to
harmonize with the gulf weed, Sargassum, among which plants
it lives.

PISCES 199

“The color of fishes is of threefold origin. The silvery luster is duc to
crystals of guanin which occur in the skin. The other colors are due
partly to numerous strongly pigmented fat-cells and partly to the chro-
matophores in the derma, which under the control of the nervous system
can alter their forms and extent and thus produce color changes in the
fish, thus adapting it to its surroundings. It is of interest to note that
destruction of the eyes results in loss of power to change color.’’!

Locomotion and Appendages.—The appendages of fishes, ex-
cept in rare instances, are the unpaired dorsal, anal, and caudal
fins, and the paired pectoral and ventral fins. ‘Fishes are
the only vertebrates having median fins supported by fin-rays.”
The fin-rays supporting all the fins are of dermal origin. The
locomotion is mainly produced by the flexing of the body and
tail, so as to propel the usually spindle-shaped animal through
the water. The fins aid in directing the movements of the fish,
as does also the air-bladder, which regulates the specific gravity
of the fish.

The skeleton is cartilaginous or bony. The notochord of the
protovertebrate becomes surrounded by a mesodermic sheath
which produces the centra of the vertebre, consisting of cartilage
or bone. From the centra are outgrowths dorsally which give
rise to the neural tube, ‘‘an inverted tunnel of cartilage’ en-
closing the cerebrospinal cavity, and ventral (hemal) outgrowths
protecting the viscera. Thelvertebre are usually amphicelous,
and the notochord persists in the cavities between the centra.
The neural arches extend throughout the spinal column, while
the hemal are complete only in the tail. In the trunk the
hemal spines are absent and the hemal processes are divided
into basal processes and ribs which surround the viscera. There
is no sternum.

The skull (Fig. 159) encloses the brain which does not fill the
cavity. The lower jaw is movable and usually bears teeth.
Some fishes have many teeth; others, few or none. They have
no other prehensile organs.

The pectoral and ventral fins are homologous with the paired
limbs of the higher vertebrates, but lack many of the bones of the
higher forms, as a comparison of the bones of man’s arm with
those of the pectoral fins will show.

1 Hertwig’s ‘‘ Manual of Zodlogy,” Kingsley, p. 559.

200 BRANCH CHORDATA

Digestive System.—The food is principally animal. Food
securing is, of course, by the mouth. The mouths of fishes vary
in size, shape, and position, according to the food and feeding
habits. The digestive tract is large, near the region of the phar-
ynx, but narrows into a tube in which there is little distinction

Fig. 159.—Right lateral view of skull of M. dolomicu, with other bones;
natural size: Pmr, premaxillary; Pl., palatine; na., nasal; Eth., ethmoid;
Prf., prefrontal; As., alisphenoid; Fr., frontal; Ptf., postfrontal; Sq.,
squamosal; Pa., parietal; Pt.o., pterotic; S.O., supra-occipital; s.l., supra-
linear; Ep.o., epiotic; k, interneural spines; La., lacrymal; Pr.s., para-
sphenoid; S.or., suborbital; Pr.o., prodtic; Bs., basisphenoid; G. Hy.,
glossohyal; D,. dentary; Art., articular; A/xv., maxillary; a, admaxillary;
Enpt., entopterygoid; Ecpt., ectopterygoid; ./.Pt., metapterygoid;
Pst.T., posttemporal; Pr.s., proscapula; Pf., pectoral fin; Hyo.C., hypo-
coracoid; Op., operculum; S.Op., suboperculum; -ing., angular; Sym.,
symplectic; n.s., neural spine; Ps/o.T., posterotemporal; 7, teleotemporal;
T’, lower teleotemporal; Bs.R., branchiostegal rays; P.Op, preopercu-
lum; J.Op., interoperculum; H..W., hyomandibular; Qu., quadrate; r., rib;
Ast., actinosts; Hyp.C., hypercoracoid. (Shufeldt.)

between the parts. Many fishes have pyloric ceca at the junc-
tion of the stomach and intestine. Others have a spiral valve,
a fold of mucous membrane increasing the digestive surface.
There is a large liver and a spleen and usually a pancreas and

gall-bladder.

PISCES 201

Excretion.—The nephridea unite in a pair of large kidneys.
The ureter may or may not empty into a urinary bladder.

Circulation (Fig. 160)—The heart is surrounded by a peri-
cardium. It consists of sinus venosus, auricle, ventricle, and
conus arteriosus. The blood, which is red, goes from the gills
over the body. The veins collect it and return it to the sinus

Branchial artery,

Arterial bulb |

Ventricle of the heart Se ,
Auricle of the heart~.../ /4

Venous sinus"; -~Dorsal artery

Vena porte, liver, etc.”

-Kidneys

lntestinc="

-Dorsal artery or aorta
Vena cavi~'

Fig. 160.—The circulatory apparatus of a fish. (Tenney.)

venosus, from which it passes through the parts of the heart in the
order named, and the circulation begins anew.

Respiration is by gills except in the lung fishes, which take the
mechanically dissolved air from the water and give off waste
matter. The gills arise as paired pouches of the pharynx and
open on the exterior by gill-slits. They are attached to the
branchial arches and are persistent through life.

202 BRANCH CHORDATA

The brain is of the vertebral type, but small, and occupies but
a small portion of the cranium. The cerebrum is comparatively
small. The cerebellum is sometimes large. The optic and ol-
factory lobes are conspicuous (Fig. 161). The medulla is also
present, all the parts being distinet and visible from above.
The brain sends off at least ten pairs of
nerves.

The Senses.—Of all the sense organs,
the most noticeable are those along the
lateral line. The lateral line on either
side of the fish from tail to head is
“marked by a groove in the scales which
opens to the exterior by numerous canals
through the scales.” (Examine several
scales along the lateral line.) The func-
tion of the lateral line is possibly to as-

Hie, 16i,— Brain. of certain the water pressure at different
a cod: og, Olfactory depths.

ganglia; ch, cerebral The shin and especially the lips are
hemispheres; ol, optic hy kak th fe : iy

lobes; c, cerebellum; € Seat or the sense 0 ouc a,

mo, medulla oblongata. The eye has several peculiarities. The
(Tenney.) lens is very convex, owing to the slight re-

fraction from the light in passing from the
water into the cornea. The eye is short sighted, since light is
so absorbed by water as to render objects a short distance away
invisible. Lids are wanting or very poorly developed. Only

a few fishes have a nictitating membrane. There are no tears.
Through disuse for generations the cave fishes have lost their
sight (Fig. 162).

PISCES 203

The ear’ has a relative size found in no other vertebrate.
There are no external ears. Many teleosts have two otoliths.
Experiments show that the ear is principally for a balancing
organ.

Fig. 163.—Stickleback and nest. (From Baskett, “The Story of the
Fishes,’ D. Appleton and Co., Publishers.)

1“ The maigre is said to produce a flute-like note audible in twenty
fathoms. Many fishes utter sounds, but perhaps the grunt (Hemulon)
on the outer Florida reef is most remarkable for the variation of the sound.
. . . The dog-fish utters a croak or bark. The gizard-shad ( Hippo-
campus), eels, catfish, porcupine-fish, sunfish, carp, gurnards, etc., utter
sounds either accidental or intentional. The sound, a single note, fre-
quently uttered by the eel is, according to Abbott, more distinctly mu-
sical than those made by other fishes.’’ (Holder.)

204 BRANCH CHORDATA

The function of the nostrils is smelling and not breathing.
For none of them, except those in the hag-fish and lung fish, open
into the mouth. The odors must come through the water. All
fishes proper have two nostrils. Experimental proof of smell is
lacking, but the well-developed olfactory lobes and nerves argue
that the sense cannot be entirely wanting.

Emotions.—If you have ever tried the sport of fishing with
hook and line, you know that fishes have emotions of fear and
curiosity. Romances says they have also those of play, anger,
pugnacity, and jealousy. In some species parental affection is
proved by the building of nests (Fig. 163) and the care of the
young; sexual feelings, by courtship; social or gregarious in-
stincts, by their ‘“‘schools.”’ !

Fig. 164.—Sawfish. Upper, profile view. Lower, view of under part.
(Pristis pectinatus.)

Means of Defense.—Fishes most often protect themselves
from their enemies by their close resemblance to the surround-
ings, or by their swift movements, darting away at the least in-
timation of danger. But many are also armed with weapons
of defense, such as the spines connected with the fins of the dog-
fish and the catfish. The mucus which flows over the spines
is somewhat poisonous, making the wound painful. The
“Scorpanoids” have a little poison sac on each side near the tip
from which the poison flows down a groove of the spine into the
wound. The Thallassophryne has, besides the dorsal hollow
poisonous spines, in which the poison sac is situated at the base,
non-poisonous spines on the gill-covers. The porcupine-fish
(Di’odon macula’ta) and the globe-fish (Chylomye’terus geome’ tri-
cus) have spines all over the body. The ‘‘surgeons’’ and rays

1 Baskett.

PISCES 205

have spines on the tail. The thresher-shark (Alo’pias vulpes)
has its pliable tail prolonged into a terrible weapon, with which,
it is said, it can kill a whale. This lashing tail serves a second
purpose by so frightening the small fishes that they crowd to-
gether and are thus easily obtained for food. The ‘‘devil-fish”’
strikes terrible blows with its broad pectoral fins. The saw-fish

Fig. 165.—Sword-fish (Tetraptu’rus), yellow-fin tuna, and yellow tail,
caught with rod and reel at Santa Catalina Island. (Bulletin of B. of F.,
vol. xxviii, 1908.)

(Fig. 164), sword-fish (Fig. 165), and the like use their long
strong jaws as frightful weapons. The torpedo and other
electrical fishes surprise and stun their victims by an electric
shock.

Influence of Temperature.—Species differ in their ability to
endure cold or heat. The brook trout loves the cool water of

206 BRANCH CHORDATA

the mountain streams, while the catfish can live in exceedingly
warm water. ‘‘Fishes have been found in hot springs of 120° F.”
The Protop’terus of Africa and Asia ‘‘so completely slimes a ball
of mud around it that it may live thus for more than one season.”
Other fishes bury themselves in the mud and estivate through
the dry season. The little ““mud-skippers”’ move from pond to
pond by the use of their pectoral fins. Other fishes migrate to
cooler waters as necessity requires. In winter some of the
fishes of our small streams hibernate in the mud, while some,
as the carp, may have the water frozen into ice about them and
live when thawed out.

Development.—The sexes are separate. Multiplication is
by eggs, which are numerous. The cod is said to lay one
million eggs. In the bony fishes the eggs are naked and numer-
ous, and fertilization usually takes place in the water.

In sharks the eggs are few and are protected by a horny shell.
In most sharks and in a few bony fishes the eggs are fertilized
and hatched within the body of the mother fish. Mating takes
place in a few viviparous forms only. Most fishes do not care
for their young “fry,” but the stickleback builds a nest and de-
fends it with great courage. There is usually no metamorphosis,
but some ocean species change almost as much as frogs.

SUB-CLASS I. ELASMOBRAN’CHII

The rays and sharks represent the Sela’chi7, in which are found
all the living elasmobranchs. They have no operculum (gill-
cover) and no air-bladder. The skeleton is cartilaginous. The
mouth and nostrils are ventral and the tail heterocercal.?
The scales are small. “The cloaca is the common outlet for the
rectum, renal and reproductive ducts.”” Some are viviparous,
others lay a few eggs, each enclosed in a chitinous case.

Sharks vary in length from 2 to 60 feet, the majority being
under 8 fect in length. Some are large and voracious, a few
dangerous even to man. Hornaday says the only loss of life
from sharks on our coast oecurred in 1830. They feed mostly
upon fishes.

The rays (Rai’id@) have the body disk shaped, broad, and flat,

' Baskett. 2 Glossary.

HOLOCEPHALI 207

the pectoral fins being much expanded. The skin is roughened
by spines or prickles. Rays most generally live on the bottom of
the sea, feeding upon fishes,
mollusks, crabs, and other bot-
tom-frequenting animals.

To the order Sela’chii belong
the skates (Fig. 166), sting-rays,
and torpedoes or electric-rays.
The saw-fish ray also belongs
to this order. Its formidable,
sharp-toothed snout, several
feet in length, makes it a
dreaded enemy. It disables
its prey by dashing into a
school of fishes, striking right
and left. Then it eats its dis-
abled prey at leisure.

SUB-CLASS II. HOLOCEPH’ALI \

This group : is represented Fig. 166.—Common skate (Raa
on our Atlantic coast by the erinacea.)

Chime’ra monstro’sa (Fig. 167).

The Holoceph’ali were formerly abundant, but are now repre-
sented by only a few genera. The skeleton is cartilaginous and
the skin is smooth. These are very peculiar looking fishes, as a
glance at Fig. 167 will show. The nostrils and mouth are ven-

tral. In general they resemble the sharks in their compressed
form, but differ from them by the large head and small mouth.
“Fossil remains are found from the lower Jurassic rocks upward.”

208 BRANCH CHORDATA

SUB-CLASS III. DIP’NOI

The “lung fishes” are snake-like or eel-like (Fig. 168), and
bear small, soft, cycloid scales, small paired fins, and a diphycer-

Fig. 168.—Lung fish (Protop’terus annecteris). (Boas.)

Fig. 169.—The Cvr‘atodus of Queensland, an air-breathing and water-
breathing mudfish of the ancient type, with paddle fins. (From Baskett,
“The Story of the Fishes,” D. Appleton and Co., Publishers.)

cal caudal fin. The skeleton is largely cartilage and the noto-
chord persistent. They live in fresh water, and usually breathe

TELEOSTOMI 209

by gills, but when the water gives out or becomes unfit for use
the swim-bladder, which may be single or double, is used for
lungs. It opens into the ventral side of the gullet and contains
air-cells. In this case the air enters through the nose.

They are interesting as showing how land forms may have
originated from aquatic forms. There are only three existing
genera: the Lepidosi’ren, of the Amazon; the Cer’atodus (Fig.
169), of Australia, and the Protop’terus, of Africa. The Protop-
terus (see Fig. 168) ‘‘can live out of water, it burrows in the
mud at the dry season and builds a cocoon lined with mucus in
which it remains quiescent until the wet season.’’!

SUB-CLASS IV. TELEOS’TOMI

To this extensive sub-class belong our bony fishes, including
most of the living fishes. It contains thousands of species.

Fig. 170.—Remoras and shark, showing dorsal fins modified into sucking
disks, by which the remora attaches itself to the shark in its commensal life,
thus securing free transportation. (From Baskett, ‘The Story of the
Fishes,’ D. Appleton and Co., Publishers.)

Familiar examples are the perch, sunfish, catfish, trout, carp,
pike, cod, and salmon. The mouth is terminal. The nostrils
are on the upper surface of the snout. The tail is homocercal
1 Hertwig.
14

210 BRANCH CHORDATA

(see Fig. 170, Rem/ora), the scales are cither ctenoid or cycloid.
These fishes vary in shape. They vary in size from our little
darter, 1} inches in length, to the ‘‘horse-mackerel,” which may
weigh as much as a cow. They differ in habits from the pre-
daceous, swift pikes and pickerels to the peculiar flounder on
the bottom of the sea.

The Remora (Fig. 170) is a lazyfish. It has a sucker on
top of its head, by which it holds fast to sharks or larger fishes,
and thus saves itself the effort of locomotion.

Order I. Crossopteryg’ii—There are only two existing genera,
Polyp'terus and Calamoichthys, of Africa.

Order II. Chondros’tei (Sturgeons) (Fig. 171).—They have
paired fins with no basal lobe, supported by dermal rays. The
pelvic fins are abdominal. The vertebral column consists of the
notochord with cartilaginous arches. The tail is heterocercal.

Fig. 171.—Common sturgeon (Alefpen'ser stu'rio). (Report U.S. F.C,
1809.)

The mouth is ventral, projectile, and toothless, and sucks up
worms and larve from the muddy bottom. The surface is
roughened by separate scales and hy five rows of bony plates.

Sturgeons are found in streams and lakes of the Northern
Hemisphere and are the largest fresh-water fishes. Those of the
lower Columbia River sometimes weigh from 800 to a 1000
pounds.

From the swim-bladder of the sturgeon, glue, cement, court-
plaster, and isinglass are made. The cegg-masses, called roe,
furnish caviare.

Order III. Holos’tei—Familiar examples of this order are the
gar-pike and the mud-fish, often called dog-fish, of the streams
of the central states.

The skull is ossified. The seales are ganoid or eycloid; the
tail, diphycercal or homocercal. The pelvic fins are abdominal.

TELEOSTOMI 211

The spiral valve is present. The double air-bladder aids in
breathing.

The gar-pike (Fig. 172) has a cylindric body covered by
rhomboid, bony scales, which are coated with enamel. The
snout is long and bony and armed with sharp teeth. This fish
is voracious. There are three species found in the fresh water of
North and Central America, including Cuba. They are from
5 to 10 feet in length.

s)

Fig. 172.—Gar-pike (Lepidos’teus os'seus). (After Tenney.)

The mud-fish or bow-fin is abundant in the shallow waters of
the Mississippi Valley. It has a somewhat bony skeleton and a
soft flesh, which is not generally used as food.

Both the gar-pike and the bow-fin come to the surface to emit
gases and to take in a fresh supply of air. They can live some
time out of water, when they use the air-bladder as a sort of
lung.

Fig. 173.—Cycloid scale. Fig. 174.—Ctenoid scale.

The three foregoing orders are often spoken of as Ganoids.
Though now insignificant, they were abundant in the Paleozoic
and Mesozoic Epochs.

Order IV. Teleos’tei.—The skeleton is well ossified. The tail
is usually homocercal. There is no spiral valve save in one
genus. The scales are cycloid or ctenoid (Figs. 173, 174), or,
in rare instances, the body is naked. The operculum is always

212 BRANCH CHORDATA

present. The swim-bladder is usually present, but its duct is
often closed. Eyes are usually conspicuous and without lids.

Reproduction is by. eggs. They are small and numerous,
and are fertilized in the water by the milt deposited by
the male at the same time. This accounts for the enormous
schools of some fishes in certain places at the breeding season
each year. They sometimes go thousands of miles to reach these
spawning places. The salmon come from the salt water up
into the rivers to deposit their eggs, which are about the size
of peas, in depressions or nests. When very small the young
salmon are banded and called parr, and later become silvery
smolt. The perches form nests or hollows in the ground near
the shore. In a form allied to the perch both male and
female form these depressions and guard the eggs. The male
Chromis of Lake Tiberias carries the eggs and young in iis
mouth. The stickleback (see Fig. 163), a small fresh-water
fish, builds a nest and the male cares for the young. The
male Loph’obranch carries the eggs in a ventral pouch, forcing
the young out by pressing the pouch against a stone. An
Indian ocean form carries the eggs in a pouch formed by the
ventral fins of the mother.

Sub-order Physos’tomi includes the catfishes, buffalo, carp,
salmon, trout, herring, eels, etc.

The catfishes (Silu’ride) are devoid of scales. The majority live in
fresh water. The head is flat and the wide mouth is provided with long
thread-like feelers or barbels. They have, for a weapon of defense, a strong
stiff spine for the first ray of dorsal and pectoral fins. They are sluggish
and abound in the muddy streams of the Mississippi Valley. The flesh is
quite free from bones and is much used for food. Some eatfishes weigh
150 pounds. ;

The common catfish guards its voung. The South American catfish
carries its eggs and young in its mouth. Other South American species
build nests of leaves in which they place their young. An electric catfish
inhabits the Nile, and blind catfishes live in subterranean streams of Penn-
aylvania.

Carps, buffalo fishes, and suckers have a naked head and usually sealy
body. The flesh is bony and not of much food value, vet quite largely used
because inexpensive on account of the immense number seined. They have
a toothless sucking mouth and are vegetable feeders, hence the intestine
is long. The air-bladder consists of two or three links. : The
shiners, minnows, and dace (Fig. 175) belong to this group. The black-
nosed dace (Rhinich’thys alronasus) is a nest builder. Both male and
female form a depression in which the eggs are deposited. Both parents

TELEOSTOMI 213

then cover them by a heap of stones placed layer upon layer to a height
of about 10 inches.

The salmon (Salmon'idw) are found in Europe and North America.
They live in salt water, but often go thousands of miles to their fresh-water

Fig. 175.—Showing longitudinal section of the nest of a dace with the
male and female fish in the nest. The stream flows in the direction indi-
cated by the arrow at the upper left-hand corner of the figure. (Bull.
Bureau of Fisheries, 1908.)

breeding places. The white fish and the various species of fresh-water
trout belong to this group and are delicious food fishes. The red-spotted
brook trout is most widely known, and is found from Maine to Dakota.
On account of its great cunning the trout is much sought by sportsmen, and
is fast. becoming exterminated in its natural haunts.

Fig. 176.—Eel (Anguil’la chrysypa). (Bull. U.S. F. C., 1895.)

Eels (Anguil'lide) have the body greatly elongated, having many ver-
tebrae, and being almost cylindric (Fig. 176). They have no ventral fins
and the “ pharyngeal and opercular bones are more or less deficient.”
The scales are minute or entirely wanting and the skin is very slimy. They

214 BRANCH CHORDATA

are mostly tropical and marine. The true eels, genus Anguilla, which
crawl “in the mud and ooze of brackish and fresh waters of most regions,
are absent on the Pacific Coast of America.”! They are very voracious
and are especially fond of shrimp and crayfish, which they find by over-
turning stones. They will also devour dead fish. They sometimes go
considerable distances in the damp vegetation on land, thus avoiding water-
falls and other obstructions. The females are larger and lighter colored
than the males and have smaller eyes and higher fins. In the spring the
eggs are deposited in the sea. It is said the young ascend rivers and after
two or three years return to the sea tospawn. A Brazilian eel (Gymno‘tus)
is electric, having two pairs of batteries in the ventral portion of its long
tail. “A metamorphosis is known only in the eel-like fishes, the larvae
of which are flat, transparent forms, with colorless blood, enormous tails,
and very small trunks. The larve normally occur in the sea at a depth
of several hundred fathoms.””?

Fig. 177.—Winter flounder (Psewdopleuronec’tes america’nus). (After
Goode.)

The blind fishes (Amblyop’side) of Mammoth Cave are colorless and
translucent. They have rudimentary eyes, but have lost their sight
through disuse for many generations. They have no lateral line. Their
knowledge of danger comes through the hearing, which is very acute. The
head is very flat and the mouth is directed upward, as food is scarce near
the bottom. They come to the surface to feed, but at the slightest noise
dart beneath stones at the bottom.

Sub-order Anacan’thini includes the cod, haddock, whiting, as well as the
flat. fishes—soles, turbots, flounders, halibuts, ete. There are nearly a
hundred species of codfish. Some reach « length of 4 or 5 fect and weigh
100 pounds. The female lays nine or ten millions of eggs ina single senrson.
They rise to the surface of the sea and hatch in about twenty days.
There is one fresh-water codfish.

The haddock resembles the cod in appearance and habits.

1 Jordan. ;
? Kingsley’s translation of Hertwig's “ Zoblogy.”

TELEOSTOMI 215

Many kinds of flounders lie upon the left side upon the sea bottom.
The young flounder is somewhat cylindric, has an eye on each side, and
swims vertically like other fishes. The eye moves over by successive stages
until both cyes arc upon the upper or right side (Fig. 177). The mouth
also becomes crooked and the under side of the fish becomes white. The
upper side is colored and its color may be changed to suit the surroundings.
“The blind flounder does not adapt its color to its surroundings.”

The halibut sometimes attains a weight of 400 pounds and a length of
6 feet. It is found on both sides of the Atlantic Occan.

Sub-order Acanthop’teri—The spiny-rayed fishes constitute
a large group, including the greater number of the marine fishes
and many fresh-water species. The stickleback, perch, mullet,
mackerel, our river bass and sea bass, and our common sunfish
belong here.

The perch is a carnivorous fish found both in fresh water and along the
scacoast and is widely distributed. These fishes spawn in winter, forming
nests in the gravel near the shore.

Fig. 178.—Large-mouthed black bass (Microp’terus salmoides). (Bull.
U.S. F. C., 1900.)

The bass and sunfish are common in our streams. The black bass is
found in clear running water from the St. Lawrence to Dakota and south to
Arkansas (Figs. 178, 179). Its length is 1 to 2 feet and it weighs from 2 to
7 pounds. It varies in color, the adult being olive green. It is a great
game fish. The sunfishes have short compressed bodies. They are
carnivorous, gamy, and usually brightly colored.

The green sunfish (Lepo’mis cyanell’us), common in streams east of the
Mississippi, makes a nest. of gravel in the shallow water and deposits several
thousand eggs, which the male guards.

The seventy species of mackerel (Scom'bride) are all marine. In early
summer great schools appear on the shores from Greenland south to Cape
Hatteras. The young from one female number from 500,000 to 600,000.

216 BRANCH CHORDATA

As they go north after spawning vast numbers are caught, whole fleets
being engaged in catching them. The mackerel is phosphorescent and the
light from these enormous schools is so great that they can be seined at
night. They are sold either fresh or sulted. One of the largest and swift-
est of the mackerel tribe is the sword-fish, in which the upper juw is de-
veloped into a long, bony, sword-like projection (see p. 205). This forms a
strong weapon, as the fish dashes into schools of fishes, cutting and slashing
and devouring them. It has becn known to pierce the wooden and copper
bottoms of vessels. It does not breed in North America. The young are
not like the adult.

Fig. 179.—Small-mouthed black bass (Vicrop'lerus dolomieu). (Bull.
U.S. F.C., 1900.)

The sticklebacks are found in both North America and Europe. They
derive their name from their formidable dorsal spines. They are small
marine or fresh-water fishes.

Sub-order Pharyngog’nathi includes the Wrasses and “‘flying-
fishes.” The pectoral fins of flying-fishes (Fig. 180) are large,
and serve as parachutes when the fishes leap from the water.

Sub-order Plectog’nathi.—To this group belong the file-fishes,
which are often protected by plates or spines, and in shape are
very deep and thin. They are common from Cape Cod to Cuba.

Here also belong the trunk-fishes, which are enclosed in a
“box” made up of bony plates or scales, the tail, mouth, and fins
being movable.

The porcupine fishes are covered with sharp spines. The
Gymnodon’ta or “‘swell-fishes’’ can inflate their bodies into spheric
sacs. Their flesh is poisonous.

Sub-order Lophobran’chii.—These fishes are covered with
rings of large plates. They have club-shaped tufted gills, no

TELEOSTOMI 217

pelvic fins, and a rudimentary tail fin. The mouth is at the end
of a long muzzle.

The pipe-fish resembles the seaweed and has the power of
changing color to suit its environment. It feeds upon small
crustacea and mollusea. It is found on both European and
American shores.

Fig. 180.—Exonautes gilberti. Type. ‘camel 546, U.S. Fish Commis-
sion.

The sea-horse (Fig. 181) has the muzzle at nearly a right
angle with the rest of the trunk, giving it a fanciful resemblance
to the head of a horse. It swims slowly by means of its dorsal
fins. It wraps its slender curling tail about seaweeds and roots,
and thus avoids being transported, unless perchance the seaweed
is floating, when the fish is carried far away from its birthplace.
It resembles the seaweeds among which it lives—an Austra-
lian species having reddish streaming filaments resembling
plants.

Economic Importance.—Fishes have been of great value since
primitive times, but the various methods of preserving them by
drying and canning has greatly added to their importance, for
they can now be shipped to any part of the world. Probably
salmon, cod, and herring are of the greatest value. The lake
and river trout, the white fish, catfish, the black, white, and
rock bass, and the perches are important fresh-water fishes,

218 BRANCH CHORDATA

though there are scores of others. The value of the annual out-
put of our streams and coasts is at least $50,000,000.

Each nation reserves all fishing rights within three miles of its
coasts. Outside of this the sca fishes are open to the world.
The largest sea fisheries are those of the Atlantic coast of the
United States, Canada, and Newfoundland, and next in import-
ance are those of northern Europe. Thousands of fishermen
from the United States, Canada, and France are engaged in the
cod-fishing on the foggy banks
of Newfoundland, whose shallow
waters furnish an abundance of
food for the cod, and make these
the greatest cod-fisheries in the
world. The fisheries along our
New England coast supply most
of the fresh cod-fish for our home
use. Gloucester is the largest
fishing port of the United States
and supplies a large part of the
salted cod-fish for our use. ‘The
Columbia and other rivers of our
northwest coast, including Alaska,
furnish our largest. salmon fisher-
ies. The salmon canning industry
of Alaska is said to be the largest
of the world.”

; % ; The demand for this whole-
Gi ae US some food product, together with
F. C., 1907.) recklessness, has caused the de-

struction of certain species in
many waters. To prevent their extermination the United
States Government has a Bureau of Fisheries which has es-
tablished fish-hatcheries in almost all the states. In these the
spawn are cared for until they hatch, and when old enough the
young fishes ure shipped to various localities for stocking ponds
and streams; or, the eges themselves may be distributed. The
food supply of these fishes is also protected or introduced, and
their enemies, diseases, and life histories are studied. The
annual distribution of eggs and young fishes numbers more than

TELEOSTOMI 219

a billion and a half. Efforts are made to rid the streams of
voracious fishes, such as the pike, pickerel, and muscalonge,
which feed upon our food fishes.

Besides being used for food, fishes furnish other useful prod-
ucts. The skin of the ‘‘dog-fish” (shark) is used as leather, and
shagreen. The bodies are used as guano or fertilizer. Oil is
obtained from the menhaden, cod, and other forms. Caviare
is a preparation of the salted roe of sturgeons, the preparation of
which constitutes an important industry on the Black and Cas-
pian Seas. Scales of some species are used in ornamental work,
and the teeth of sharks are used as weapons by Pacific Islanders.
The swim-bladders of cod-fishes are used in making isinglass.
They are also pickled and eaten under the name of “‘sounds.”

Geologic Distribution.—Teeth of the true fishes have been
found in the Ordovician of Europe. The remains of sharks prove
their existence in the Silurian. Fishes are found in great variety
and abundance in the Devonian Period, the sharks, lung-fishes,
Crossopterygii and the Ganoids, the most advanced, are repre-
sented. The bony fishes (Teleosts) are entirely absent in the
Devonian. These, according to Scott, are approximated by
some of the Jurassic fishes. In the Cretaceous Period, Ganoids
become rare and Teleosts take the dominant place among fishes.
Marine and fresh-water fishes assume the modern forms in the
Eocene Epoch.

Important Biologic Facts.—The skull is a continuation of
the vertebral column, and contains, but is not filled, by a genu-
ine brain. The vertebre are amphiccelous, that is, concave at
each end. The true fishes have true jaws.

They have a closed, though an incomplete circulation.
The blood-corpuscles are red.

The multiplication is sexual, but the eggs, or roe, are ferti-
lized in the water.

The skin of vertebrates is distinguished from that of inverte-
brates by the many layered condition of the epidermis and the
thickness of the dermis. The scales of fishes are of dermal origin
and different from the epidermal scales of reptiles. It is
from the dermal scales that the bony plates of turtles and
armadillos have arisen, as well as the secondary or membrane
bones.

220 BRANCH CHORDATA

The strange development or change of the flounder from a sym-
metric to a “flat” fish demonstrates the principle that special
habits of life result in special modifications of structure which
fit the animal for those habits.

The lung-fishes (Dipnoi) show many advancements toward
the air-breathing conditions, such as the swim-bladder used as
a lung and the partly separated auricle, and the flipper with a
central axis rather than a fin, so that zodlogists are led to be-
lieve that they may represent the division of fishes from which
the amphibians sprang.

Classification.—

Sub-phylum Vertebrata or Craniata.

Class I. Cyclostém’ata. Lamprey, hag-fishes.
Order I. Petromyzon’tes. Lamprey.
Order II. Myxinoi‘dei. Hag-fishes.

Class II. Pis’ces.

Sub-class I. Elasmobran’chii.

Order I. Cladosela’chea. Extinct shark-like forms.
Cladoselache.

Order II. Pleuracan’thea. Extinct Pleuracanths.

Order II]. Sela’chi. Extinct forms and all the

living Elasmobranchs,
as sharks and rays.

Sub-class II. Holoceph’ali. Three genera of Chime-
ride.
Sub-class III. Dip’noi.
Order I. Monopneu’mona. Ceratodus.
Order II. Dipneu’mona. Protopterus and Lepidosi-
ren.

Sub-class IV. Téleos’tomi.

Order I. Crossopteryg’ii.
Order II. Chondros’tei.
Order III. Holos’tei.
Order IV. Teleos’tei.

AMPHIBIA 221

CLASS III. AMPHIBIA

To this class belong the toads, frogs, salamanders, and
newts. The skin is smooth, as in the frog, or warty, as in the
toad, with a glandular secretion. Itis often highly colored
owing to the pigment cells in the deep layers. In the common
“tree-toad,’’ as well as in some of the
terrestrial frogs, the color may be
changed to harmonize with the en-
vironment. No amphibians are ma-
rine. Most of them are aquatic or
scmi-aquatic. In the adult stage some
are terrestrial, some arboreal. They
are usually carnivorous in the adult
stage, but the larve may be herbivo-
rous. They hibernate in the mud at

Fig. 182.—Bullfrog. (Skeleton (Skeleton
cleaned and mounted by stu- cleaned and mounted by stu-
dents.) dents.)

the bottom of a stream and may live a long time without food.
They make fine specimens for study in a tank or tub, since
many of them will endure captivity a good while.

229 BRANCH CHORDATA

Fig. 184.—Anatomy of common frog: A/y, mylohyoid; sr, sternoradials;
th, thyroid; /u, lungs; f, fat-body; Te, testis; S/, stomach; Sp, spleen; R,
rectum; a, adductor longus; mr, vastus internus; ms, sartorius; ri’, rectus
internus major; (a, tibialis anticus; g, gastrocnemius; r7’’, rectus internus
minor; a’’, adductor magnus; rab, rectus abdominalis; B, bladder; vd, vas
deferens; 6, gall-bladder; A7, kidney; pr, portal vein; Li, liver; V, vena
cava inferior; Ao, aorta; S, vocal sac or croaking-bag. II. Origin of the
arterial trunks: J, Arteria ingualis; cg, carotid gland, which is merely a
rete mirabile; cr, carotid artery; .10, nortie arch; Pa, pulmonary artery.
III. Dorsal view of muscles of hind leg: gl, Gluteus; ra. rectus anterior;
Pp, pyriformis; ve, vastus externus; sm, semimembranosus: b, b. biceps; g,
gastrocnemius; per, peroneus. (Irom drawing by C. 8. Minot.) (From
Packard’s ‘‘ Zodlogy,”” Henry Holt & Co., Publishers.)

AMPHIBIA 223

The Skeleton.—There are two occipital condyles. The ver-
tebre of the lower forms are like those of fishes, biconcave;
those of higher Amphibia are usually concavoconvex. A
sternum first appears in this class, as well as a typical vertebrate
limb-skeleton. The pelvic girdle is united with the spinal col-
umn. There may be four, two, or no limbs, that take the place
of fins. They have digits which are generally without claws.1
The tail is temporary in frogs and toads and permanent in
other amphibians. Teeth are present in most amphibians, but
lacking in the toad. They are small, sharp, and point back-
ward.

Respiration — Amphibians breathe by gills in the larval or
tadpole stage, and in the adult forms by persistent gills or by
persistent gills and lungs, as in Necturus, or by lungs, as in the
salamander. The skin is also an important organ for taking in
oxygen and giving off impurities. The frog breathes with the
mouth shut, by lowering the tongue and taking in air through
the nostrils, then raising the tongue, closing the nostrils, and
forcing the air into the lungs.

Circulation (Fig. 184).—Amphibians are poikilothermal. The
heart has one ventricle and two auricles. The arteries carry the
blood to all parts of the body. The veins from the lungs return
the pure blood to the left auricle, and those from the body return
the impure blood to the right auricle. The auricles contract
and force both pure and impure blood into the ventricle, which
forces it out in such a manner that the venous blood goes to the
body and the pure blood to the head.”

The Nervous System (Fig. 185).—The brain of a frog has
advanced above that of the fish in the development of the cere-
brum, but the cerebellum, which is very small, being, in fact,
but a thin lamella, is inferior to that of the fish.

The skin on the whole surface of the body is provided with
tactile nerve-endings. Special taste organs are located on the
tongue and mouth. Jn adult amphibians the nostrils open
into the mouth, and Baskett says, “there is much in the
arrangement of the mucous membrane of the frog’s nose which
implies that it smells.” The strong odors of some of their ex-

1See ‘‘ Amphibia and Reptiles,” Gadow, p. 146.
2 Linville and Kelly’s ‘‘ General Zodélogy,’’ p. 330,

994

ae BRANCH

CHORDATA

cretions would also imply a sense of smell, but these may be

wholly for defense.

oS | 1] a

x

Fig. 185.—Brain and spinal cord
of frog (x about 2): a, Cerebral
hemisphere; b, olfactory lobe; c¢,
eye; d, thalamencephalon; e, optic
lobes; f, cerebellum; g, medulla
oblongata; h, fourth ventricle; i,
spinal cord; I, Olfactory nerves;
II, optie nerve; IL, oculomotor
nerve; IV, pathetieus; V, fifth
nerve; VII, facial nerve; VIII,
auditory nerve; 1X, glossopharyn-
geal nerve; X, vagus nerve; 1-10,
first to tenth spinal nerves; 2 and
3 unite to form the brachial, and
7, 8, and 9, to form the sciatic
plexus. (Shipley and McBride.)

The nostrils! of toads and frogs can be

closed by special muscles.

The lateral line of the tad-
pole disappears in the adult. It
seems that whatever senses may
be located in the lateral line,
they are ineffectual outside of
water.

In most amphibians there is
an internal ear which opens by
one or two openings into the
mouth, back of the openings
from the nostrils. None of them
have any outside opening to the
ear, but most of the higher forms
(Anura) have a drum-cavity and
a tympanic membrane over it,
lying at the surface. A single
bone, the columella, lies across
the middle ear and has one
end against the tympanum.
There is no cochlea, or at least a
very rudimentary one; hence it
does not seem possible that the
frog can detect differences in
pitch. Perhaps this accounts for
his monotonous song. Yerkes
found that frogs ‘‘straightened
up and raised the head as if list-
ening when other frogs croaked
or splashed into the water,” but
found it impossible to make them
respond in any way to any noise
he himself made so long as he
remained invisible.2 He thinks
they depend on sight for the

1“ There seems to be no experimental proof of specific taste or smell

among amphibians or reptiles.”—Washburn,

* Linville and Kelly,

AMPHIBIA 225

knowledge of danger. Romanes records an instance of a pet
frog which would come when his name, ‘“‘Tommy,” was called,
no matter at what time of day, though fed only at morning, and
another instance of a toad kept as a pet for thirty-six years,
which knew all of his friends. In either case, the knowledge
might have been gained, at least in part, by sight.

The eye has no lids in the lower forms, and is degenerate in
the Pro’teus, which lives in caves (see Fig. 189), and in some
Gymnophi'ona. Most of the Anura have an upper lid, but no
lower one. There are no tears. The “flying tree-toad”’ has
large owl-like eyes (see Fig. 195), so that it can see as far as it
leaps. Frogs are able to project the eyes upward to give greater
range of vision. When the mouth is inflated the eyes are pushed
forward, since there is no partition between the eyes and mouth.
It is well known by boys that frogs recognize bright colors, and
it has been proved by experiment that they can distinguish red
from white.

Development.—The eggs of Anura, which consist of the
yolk enclosed in a mass of jelly-like matter, are not surrounded
by a shell. They are usualy deposited in masses (frogs) or in
strings (toads), and then left to hatch by the heat of the sun.
The little tadpole has a small sucking mouth and a slender active
tail. The branched gills soon grow out on the sides of the neck,
but are later replaced by internal gills, when the water passes
in through an opening on each side of the neck. The tail is
gradually absorbed, the legs develop, the holes on the sides of the
neck close, and the limbs develop underneath the skin, the hind
legs coming out first in the frog forms, but in all others it is the
fore limb that first shows.!. Meanwhile ‘the tadpole ceases to
feed, the whole intestinal canal is voided of its contents, and, by
histolysis, is entirely rebuilt, becoming wider and shrinking
to about one-sixth of its original length, undoing thereby the
spiral, preparatory for the coarser food, which consists of in-
sects, worms,’ and any live animals it can capture.

Care of the Young.—Usually the parents take no care of the
young, but there are some interesting exceptions. The little
South American frog (Rhinoder’ma dar’wint) carries the eggs in

' Baskett, “ Story of the Amphibians and Reptiles,” p. 34.
2 Gadow, p. 61.
15

226 BRANCH CHORDATA

the immense vocal sacs of the male until they are hatched. A
tree frog ( Hylo’des linia’tus) of Dutch Guiana carries its young,
which cling by sucking disks, upon its back. The “Surinam
toad” (Fig. 186) places the eggs upon the back of the female,
where the skin is soft and spongy, during the breeding season.
Each egg sinks down and is covered by a jelly-like film. They
remain embedded here until the tadpole stage is passed. The
pouched frog ( Nototre’ma marsupia'tum) has the eggs stored in a
pouch on the back, where they hatch and the larve develop.
The male of the European species (A‘lytes obstet’ricans) winds the

Fig. 186.—Surinam toad, showing young escaping. (From Holder’s
“Elements of Zodlogy,” American Book Co., Publishers.)

string of eggs about the thighs and body. A Japanese frog
makes a nest on the ground. One in Brazil makes circular nests
in shallow water, smoothing and shaping rings of mud and laying
the eggs in these cup-like depressions. Many amphibians are
viviparous.

Defense.— Almost all amphibians are more or less poisonous,
says Gadow. It has been proved that if a quantity proportion-
ate to the size of the animal be injected, that the poison secreted
by toads, salamanders, and newts will kill mammals, birds, rep-
tiles, and fishes. The poison acts upon the heart and central

1 Baskett, see ‘‘ Viviparous Amphibians,”

AMPHIBIA 227

nervous system.! The Indians of Columbia, it is said, use the
secretion of Dendrob‘ates tincto’rius for poisoning arrows to shoot
monkeys. That this secretion protects these amphibians from
their enemies (the “glass snake” is an exception) is evident from
the fact that ‘“‘a dog that has once been induced to bite a toad
suffers so severely that it will not repeat the experiment.’’ The
handling of the tree-frogs irritates both nose and eyes. Many
of the most poisonous amphibians (as Salaman’dra maculo’sa,
Bom’binator, and Dendrob’ates) are conspicuously marked with
yellow and black. The horned frog of South America, which
fights and poisons its antagonist, is brilliant in green and gold.
Many assume a threatening attitude. “Toads normally have
the sections of the breast-bones overlapping, so that they can
swell themselves enormously when angry.’”?

Ec’dysis——All amphibians shed the epidermis. The first
ecdysis occurs at the time the metamorphosis is completed,
preparatory to terrestrial life. The Anvw’ra roll up the cast-off
skin and swallow it. The Urode’la also eat it. The skin of the
Anura generally splits down the back, but that of the Urodela
breaks loose around the mouth, and the animal slips out, turn-
ing its hide wrong side out. So long as growth continues, the
skin must be shed often, as this outside layer will not ‘“give”’
to make room for growth. The adult Urodela do not molt
often, but usually at the breeding season, when they go to the
water to deposit their eggs. The Anura molt frequently, at
least every few months, probably to keep the skin moist.

Voice.—Most of the Anura and some of the Urodela have a
voice produced by the larynx, which is often provided with a
complicated cartilaginous and muscular apparatus and with
vocal cords. The female of the Anura is mute or utters only a
grunt. The sound made by the male is called a croak. The
voice of Urodela is a feeble squeak. The song of frogs and toads
is usually of the nature of a serenade to its would-be mate, for
they do not, as a rule, cry out in fright nor in rage. A notable
exception is that of the vicious horned frog of South America,
which is said to defy its foes with a sort of bark, but which has a
clear bell-like tone for its friends. Our common green frog is

1Gadow, ‘‘ Amphibia and Reptiles,” p. 38.
° Baskett, p. 29.

228 BRANCH CHORDATA

also an exception. That cloudy or damp weather has some
effect in making certain species, as the, tree-frogs, sing, is per-
haps explained by the fact that the skin of amphibians is used as
a breathing organ as well as for a body covering, and it must be
kept moist to be serviceable.

Influence of Temperature.—Amphibians living in the water
assume its temperature, which varies much from noon to mid-
night, and from the stream in open sunshine to the cool, shady
spring. According to Gadow, “most Anura die when their tem-
perature rises to 40° C.,”’ but those outside of water in open air
endure greater heat than aquatic ones, since the evaporation of
the moisture from their skin lowers their temperature. Most
of them, and especially the drier skinned toads, seek the cool
shade or even estivate during the hottest part of the summer.
Many of them, unless they are used to tropical climates, can en-
dure a very great amount of cold, their temperature sometimes
falling to the freezing-point during hibernation. Our spotted sal-
amander, in a jar of water out-doors, was forgotten one severely
cold night, when the water about it froze solid. It was put into
a cool room and allowed to thaw gradually as the weather moder-
ated, after which the salamander seemed to be as active as ever.
Of course, the animal was not sawed into parts to find out if
it was frozen solid, but it surely looked solid enough. It does not
seem possible that the heart was absolutely frozen, for the heart
“must not itself be frozen if the animal is to have a chance of
recovery.””!

CLASSIFICATION OF AMPHIBIA

OrderI. Stegoceph’ala.—Thisis an extinct order of amphibians,
described by Scott as animals, which have a skull “well covered
with a roof of sculptured bones and which are of moderate or
small size, not exceeding 7 or 8 feet in length and mostly much
smaller. The backbone is not ossified, the limbs are weak, the
tail short and broad, and in many forms the belly is protected
by an armor of bony scutes.’ Most of them were like sal-
amanders in shape, but some were long and snake-like.

Order II. Ap’oda or Gymnophi’ona.—This group comprises
one family of limbless, tailless, vermiform, subterranean am-

1 Gadow, p. 68.
2 Scott, ‘‘ Introduction to Geology,” p. 427.

CLASSIFICATION OF AMPHIBIA 229

phibians of the tropical regions. They have from two hundred
to three hundred vertebre. There are no gills or gill-slits in the
adult stage. Their mode of locomotion is much like that of the
earthworm. It is produced by the peristaltic motion of the
skin, aided by the numerous ring-shaped constrictions. The
eyes are vestigial and concealed beneath the skin.

The only family is Cecili’ide, with some forty species. Some genera,
as Ichthyophis, have small scales embedded in the skin. Others, as the
Typhlonectes of Guiana and Venezuela, are scaleless. TJ’. compressicauda
is 18 inches long and 2 inch in diameter. Its color is from an olive brown to
black, which is the general color of most species. Nome, as [chthyophis, are
oviparous; others, as Dermophis, are viviparous.

Order III. Urode’la or Cauda’ta.—These are the tailed and
limbed amphibians. They have four limbs, as in the toads and

is eras a ON
Fig. 187.—Siren (S7’ren lacerti’na). (Chapin and Rettger, Englehard &
Co., Publishers.)
frogs; or two, as in the Siren. The skin is smooth and slimy.
Locomotion is accomplished mostly by body motion, aided by
the weak limbs, in strong contrast with the limb-motion of the
frogs and toads. They are not very common as compared with
frogs and toads. Newts and salamanders are examples.

_Sirenide is a small family of two genera of one species each. The
“mud-eel’? (Siren lacertina) (Fig. 187) of the southern United States is 2 or
3 feet long. Posterior limbs are wanting, and the weak anterior limbs have
four digits. The tail is long, compressed, and thin. There are three pairs
of gills, but they atrophy in the young and are redeveloped subsequently.1
The mud-eel is a harmless creature, burrowing in the mud of ponds and
ditches. Dorsally it is dark colored, but lighter ventrally. Sometimes

1 Gadow, p. 136.

230 BRANCH CHORDATA

it is spotted with small white specks. When swimming, the limbs are folded
back.

The other species (Pseudobran’chus stria’tus) is only about 7 inches in
length and has three digits to each fore foot.

Fig. 188.—Mud-puppy. (Chapin and Rettger, Englehard & Co., Pub-
lishers. )

The family Prote’ide consists of amphibians having three pairs of per-
sistent gills, two pairs of weak limbs with four digits to each one, or the

Fig. 189.—Pro’teus angui’nus. Europe. (rom Dodge's ‘* General Zodl-
} * os .
ogy,” American Book Co., Publishers.)

anterior pair with two, and the posterior with three digits. The eyes are
without lids and covered by a transparent skin, but are functional. They
have teeth on the vomer, mandible, and premavillaries.

CLASSIFICATION OF AMPHIBIA 231

The water-dog or mud-puppy (I*ig. 188) ( Nectu’rus macula’tus) is a rather
common, clumsy form found in the Mississippi Valley and the region of the
Great Lakes and east to the Alleghenies. They are nocturnal, but vora-
cious, feeding on insects, worms, small fish, and crustaceans. Those in
our laboratory were 15 inches long with dark brown spots.

The blind Pro’leus angut’nus of Europe (Fig. 189) belongs to this family.
It is white and lives in total darkness in a temperature of about 50° F. If
brought to the light the skin will ultimately change to a dark color.
There is a similar species (Z'yphlomol’ge rath’buni) in Texas.

Family Amphi’imide.—These animals are without gills in the adult
ciage: They have teeth in both jaws. They have four small, weak
imbs.

The hellbender (Cryptobran’chus alleghanien'sis) is a stout-bodied, four-
footed, ugly, but harmless amphibian, which is sometimes 2 feet in length.
It is brown or gray above and lighter below. It feeds on worms, crayfish,
fish, and such other creatures as it can obtain in its aquatic habitat. It is
restricted in its distribution to the streams of the mountainous regions of
the eastern United States.

Fig. 190.—Congo snake (Amphiu’ma me‘ans). (From Holder’s “ Elements
of Zodlogy,’” American Book Co., Publishers.)

The giant salamander of Japan (C. japon’icus) reaches a length of 4 to
5 feet. It lives in small streams and mountain meadows of Japan and
China, from 600 to 4500 feet above sea-level. Sasaki reports that it lives
singly, lying concealed under rocks, in swift, thickly shaded, small, clear,
cold streams. It feeds on animals which it can capture in the water and
may be caught with a fish-hook. It is used for food by the Japanese.

The ‘Congo snake” (Amphiu’ma me’ans) (Fig. 190) is eel-like, with
four weak limbs, having two or three toes each. Its general color is black,
with lighter under parts. It attains a length of 3 feet. It lives in the
swamps and rice fields of the southeastern United States. It feeds on
crayfish, mollusks, and fishes. It is quite harmless.

Family Salaman‘dride, or salamanders and newts, are our most common
Urodela. All are harmless, and are generally but erroneously called
lizards. They have no persistent gills. They have two pairs of weak
limbs. Nearly all have movable eyelids and teeth in both jaws. There
are twelve or fifteen species in the United States.

232 BRANCH CHORDATA

The spotted salamander (Amblys’toma puncta’tum) is our common species
in the Mississippi Valley (Fig. 191). It is dark brown or blackish above,
marked with about thirty irregular yellow spots. It is found in wells and
cellars. It is oviparous.

One species (Amblys'loma ligri’num), which is found in Mexico and Cali-
fornia and cven in New York and Minnesota, affords a striking example of
neoleny,! or the “more or less complete retardation of development, or the
retention of partially larval conditions.’’? If the pond in which this azolotl,
or Jarva (Fig. 192), lives begins to dry up, its gills, fins, and tail shrink, and
finally disappear, the animal begins to breathe air, and gradually becomes a
terrestrial salamander.’ But if it is reared in deep water or forced by deep
walls to remain in aquatic conditions, the larval or aquatic gills and tail
are retained, even after sexual maturity has been reached. One would
think this was a forcible proof of the influence of environment on the
development of the individual, but the strangest part of it is that it is said

Fig. 191.—Common yellow spotted salamander. (Morse.)

there have sometimes been found, side by side with these prolonged larval
individuals, others apparently of the same species which have completed
their metamorphosis.! :

The newts or tritons all prefer moisture without heat. In the mating
season they take to the water, undergo various changes, and become
aquatic. After the breeding scason is over, they become terrestrial, hiding
in cracks or in the sand. Some estivate in the hot dry season. They
hibernate usually in the ground, but sometimes in ponds. The food con-
sists of insects, centipedes, and snails. ‘‘ They do not drink, but soak them-
selves in water.’

' Baskett and Ditmars.

° Parker and Haswell.

3 Linville and Kelly.

4 Hertwig (p. 587, IXingsley’s translation) says adults of true axolotl are
unknown.

5 Gadow, p. 123.

CLASSIFICATION OF AMPHIBIA 233

The crimson-spotted newt (T'ri’ton virides’cens) is abundant in northern
and eastern states. Above, it is greenish brown, with two rows of crimson
spots. Below, it is orange, with black dots. It lives in deeper water than
is usual for salamanders and ‘ ‘swims freely, often in an upright position,
with hind legs hanging motionless, while the tail does all the work.”

Order IV. Anu’ra or Ecauda’ta.—‘‘The Anura are a very spe-
cialized group. Their development (see p. 225) indicates their

Fig. 192.—Axolotl, a creature living and breeding for generations in the
water. Amblystoma coming out of the water. Amblystoma breathes by
lungs, having lost its gills. (From Holder’s ‘“ Elements of Zodlogy,”
American Book Co., Publishers.)

derivation from branchiate, tailed forms, but there is no paleon-
tologic evidence on this point.’

Aglos’sa.—This group is characterized by the absence of a
tongue and by acommon opening for the Eustachian tubes. It
is represented by the Prpa or “Surinam toad” of South America
(see Fig. 186) and by the Dactyl’ethra (Fig. 193) of Africa.

1 Parker and Haswell, p. 291.

234 BRANCH CHORDATA

Phaneroglos’sa.—This group is characterized by the presence
of a tongue and by distinct Eustachian tubes. It includes the
toads and frogs. Gadow estimates 900 species in the world.
Frogs and toads have tails in the larval or tadpole (Fig. 194)
condition, but are tailless in the adult stage. The body is
short and stout. They have a small number of trunk vertebre
and the caudal vertebrz are replaced by one long bone, the uro-
style. They have four limbs, the posterior ones, long, strong, and
adapted for leaping or hopping. Toads are crepuscular and
nocturnal. They hibernate in the
mud at the bottom of the water.
The tadpole or ‘“ pollywog” is
fish-like and aquatic. It has a
long tail and breathes by gills.
Its intestine is very long, adapt-
ing it to its vegetable food.

Family Bufon‘ide.— Toads are
clumsy, stout-bodied, nocturnal insect-
fecders. The tongue is fixed by the
anterior end and can be thrust out to
catch its food. They have no teeth.
The skin is warty or glandular and
secretes a fluid for protection. The
toes are webbed, but not dilated at the
tips. Toads resemble the ground very
closely.

The American toad (Bu’ fo lentigino’-
sus) is familiar to all. The young are
nearly smooth, the adults warty. They
are brownish-olive, with a yellowish
median line and brown spots. There isa bony ridge behind and above
the eye and two black patches below the eye. The tympanum is large.

Family Hy'lide or Tree Frogs.—These are arboreal frogs with an op-
posing thumb and with adhering disks on the end of each toe, by which
they cling to the trees in which they live.

Our most. common example is the northern tree-frog (Hy'la ver’sicolor) of
the eastern United States and Canada. It is about 2 inches long and deli-
cately colored. ‘‘ Its color passes within a short time from dark brown or
olive gray to pale gray or white, occasionally retaining a few large dark
patches on the back and delicate eross-bars on the limbs.” It has small
warts, which produce an acrid secretion. It is found not over 20 feet from
the ground in trees or on lichen-covered stone fences. Its color renders
it almost. perfect. in protective resemblance. One may be within a foot of
it and not be able to distinguish it. It croaks noisily in the evening or
just before a rain. In croaking its vocal sacs swell to enormous pro-
portions. It remains quiet in the shade during the day, but is lively in

Fig. 193.

Dactyl’ethra capen -
sts. (Claus.)

eae

CLASSIFICATION OF AMPHIBIA 235

Fig. 194.—The metamorphosis of the frog. The numbers indicate the
sequence. (Galloway after Brehm.)

Fig. 195.—F lying tree-toad of Borneo (Rhacoph’orus). (After Wallace.)

236 BRANCH CHORDATA

the evening, feeding on insects. Gadow mentions a tree-frog which lived
twenty-one years.

Family Ran’‘ide.—Frogs (Runinw) have teeth in the upper jaw. The
toes, four to five, are more or less webbed. The tongue is like the toad’s.

Our largest species is the bullfrog (Ra’na culeshia’na), which measures
from 5 to 8 inches. It is known by its deep bass voice. It has two
large internal vocal sacs. Its toes are broadly webbed. In color it is
varying shades of green above, with faint dark spots, the head is bright
green, the legs blotched. The tympanum is large. Its hind limbs are
much prized for food. — Bullfrogs ure solitary except in the breeding season,
when hundreds collect in the same small pond. They are commonly found
sitting half immerscd in water, or waiting for their prey upon the banks
of apond. The bullfrog is voracious, devouring mollusks, fishes, and frogs,
as well as ducklings and young watcr fowls. It is eaten by fishes, birds,
otters, snakes, and alligators.

The green frog (i. clamala) is a brownish-green color, brighter in front,
with irregular small black spots, and blotched limbs. Below, the color is
yellowish white. The tympanum is large. It is common in the eastern
United States. The vocal sacs are small and internal.

Wallace describes a species of Ranidw which was brought to him in
Borneo. The body was about 4 inches in length and the webs of both fore
and hind feet were enlarged and uscd. as parachutes by these “' flying frogs”
(Fig. 195).

Classification.—
Order. Examples.
I. Stegoceph’al’ia. Extinct forms.
II. Ap’oda or Gymnophi’ona. Ceeciliide.
III. Urode’la or Cauda’ta. Necturus, Salamanders.
IV. Anu’ra or Ecauda’ta. Frogs, Toads.

CLASS IV. REPTILIA

This class of Chordates consists of snakes, lizards, turtles,
crocodiles, and alligators, together with a number of extinct
orders.

Reptiles are scaly. They are aquatic or terrestrial; a few
are arboreal. There is one occipital condyle, and the lower jaw
is united to the base of the skull by a quadrate bone.

The limbs are four, two (the Python and some kindred forms
have the vestiges of the hind limbs only), or none, as in the
“lass snake” and our common snakes.

Reptiles are poikilothermal. The heart has one ventricle
and two auricles, except in order Cro’codilia, where the heart has
two auricles and two ventricles.

REPTILIA 237

GpLEUS

From INSIDE

pee pa

EAGLE

From INSIDE

OTARIA

Sea LION

Puica

THe EYEBALL
REMOVED

MAN

Fig. 196.—Illustrations of the nictitating membrane in the various
animals named, drawn from nature. The letter N. indicates the membrane
in each case. In man it is called the plica semilunaris, and is represented
in the two lower drawings under this name. In the case of the shark
(Galeus) the muscular mechanism is shown as dissected. (Romanes.)

238 BRANCH CHORDATA

Reptiles always breathe by lungs. “The air is drawn into
the lungs of snakes, lizards, and crocodiles by the play of the
ribs.’”!

The nervous system is somewhat more highly developed than
in the amphibians. There is a middle and an inner ear. The
eye has an upper and a lower movable eyelid and also a nicti-
tating membrane (Fig. 196). True nostrils and salivary glands
appear first among the reptiles.

Reptiles are oviparous, ovoviviparous, or viviparous. There
is no metamorphosis.

In ecdysis the skin may be cast in one piece, as in all snakes
save sea-snakes and in most lizards; in strips, as in some lizards;
in little pieces, as in the western horned toads; or in flakes, as in
the geckos. Some tortoises shed the whole outer layer of epi-
dermal shields periodically.

Gadow briefly defines Reptilia as ‘‘monocondylia with a scaly
skin.”

Reptiles live longer than most warm-blooded animals. A
turtle in the Zodlogical Park, New York, says Ditmars, is esti-
mated to be over three hundred and fifty years old.

ORDER I. RHYNCHOCEPHALIA

Rhynchocephali is represented by Sphen'’don puncta'tum
( Hatte'ria) of New Zealand. It is a lizard-like, four-limbed,
pentadactyle, nocturnal, carnivorous reptile.

Its color is dark olive green, with small white or yellowish
specks on the sides. Its length is from 15 to 30 inches, while
fossil forms were sometimes 6 feet long. A row of spines ex-
tends along the back. Its means of defense are biting and
scratching. It burrows. It lays about ten hard-shelled white
eggs in the sand.

Gadow has “come to the conclusion that they are dull, not
companionable creatures.’’ Their sound is a grunt or croak.

For an interesting description of this living fossil read Gadow,
“Amphibia and Reptiles,” pp. 294-300. Look at the picture of
the skeleton and state the branch, class, and ordinal character-
istics you sec.

' Dodge.

OPHIDIA 239

ORDER II. OPHIDIA

Snakes are considered degenerate lizards, and by some zo-
ologists are classed with the lizards, and the group together
called Order Squamata.

The Ophidians are reptiles with no fore limbs, no peetoral
girdle, no sternum or sternal ribs, but the ends of the dorsal
ribs are connected with the ventral scales, or scutes, and both

A. VENT,
\ : i: HORNY SReRnulerion, oF
RvoiMeNTARy HiNd-LIMBS
Fig. 197.—Rudimentary or vestigial hind limbs of python as exhibited

in the skeleton and on the external surface of the animal (4 natural size).
(Romanes.)

scales and ribs aid in the body motion. ‘A snake literally
walks on the ends of its ribs.”

Vestiges of the hind limbs (Fig. 197) sometimes appear as little
spurs on either side of the vent. The ribs, which begin with the
second vertebra and continue to the end of the body, aid in res-
piration. They aid in locomotion also, their ventral ends fitting
into the ‘“‘connective tissue of the sides of the ventral transverse
scales (scutes).”” The body is long and the vertebre very numer-
ous.

They vary in size from the enormous ones of the tropics to
our little green grass snakes. Some are aquatic, some terrestrial

240 BRANCH CHORDATA

or subterranean, while still others are arboreal in their habits and
habitat.

The color of snakes is usually brownish or green, which affords
a good protective resemblance to the ground or grass upon which
they creep.

The skin is sealy. The horny epidermis is shed from one to
several times yearly, the whole outer skin, from lips to tail, being
turned wrong-side out, even to the transparent covering of the
eyes. The first molting takes place “within forty-eight hours
after birth’? before the young snake begins to feed. In the
rattlesnake, at each time the skin is shed, ‘there is left a ridge
or rim of it at the tail, which forms the rattle.”

Food.—Since there are no limbs for prehension, snakes must
depend upon the mouth to secure the prey, which is swallowed
whole. The constrictors, like our common blue racer and the
boa constrictor, wind their bodies about their victims and
literally squeeze them to death. The teeth point toward the
throat, thus preventing the escape of the prey from the mouth.
The snake has also a distensible lower jaw, enabling it to swal-
low an animal as large or larger than the diameter of the snake’s
own body. The bones and palatal apparatus are united by
ligaments only, thus allowing them to spread apart in the
process of swallowing. An abundant supply of saliva (which
appears first in reptiles) renders swallowing the more easy.

Snakes are carnivorous, feeding upon mice, birds, frogs, and
insects. Poisonous snakes should he killed, of course, but the
non-poisonous ones are quite useful in the fields in destroying
vegetable-feeding animals, especially rodents and insects.

Respiration is mainly by one lung, the other one being
rudimentary. The trachea may be slightly protruded between
the halves of the lower jaw during the process of swallowing, to
prevent suffocation.

Senses and Intelligence.—The eves are not movable nor have
they a movable eyelid, henee their glassy stare. The lacrimal
fluid passes internally into the nasal cavities. No external ear
is visible, though the hearing is good. The sense of smell is
well developed, some snakes being greatly aided by it in their
search for prey. The tongue, which is slender, forked, and
sheathed, is protractile, moist, and very sensitive to touch,

OPHIDIA 241

Snakes, while showing considerable intelligence, are seldom
much attached to their keepers, being more often reticent and
surly.

Multiplication.—The eggs of snakes are not hard shelled,
but are covered with a tough membrane. Generally the snake
loosely buries the eggs or deposits them half-hidden in cracks
and crevices. Many snakes are ovoviviparous.! The young
are precocial. Male snakes are smaller than the females.

As in reptiles generally, the number of young at a litter is
large, but the number varies with the species. That of the
poisonous snakes is said to seldom exceed fifteen, except those
of some of the tropical ones. Ditmars mentions a boa con-
strictor in captivity which “‘ gave birth to sixty-four fully devel-
oped young, while a huge python deposited seventy-nine eggs,
which she gathered in her coils and guarded jealously” until
hatched. During this period of incubation the body tempera-
ture is raised. Our little garter snake has a litter of about
thirty-five, while that of the common water snake has been
known to number sixty. The copperhead has about eight or
nine young.

The length of life may be said to be considerably shorter than
that of the chelonians and crocodilians, as growth is more
rapid. Adult snakes received in the Zodlogical Garden, New
York, says Ditmars, have been kept for ten years without show-
ing signs of age, and pythons even fifteen years. The snakes
of this latitude hibernate in caves and dens or in deep crevices
between the rocks. In the tropical regions some species esti-
vate in summer.

Defense.—Besides their protective coloration, snakes are
further provided with several means of defense. Some are
protected from their enemies by a characteristic odor, while
others have the deadly poison fangs. Another, and by far the
most common means, is by noiseless flight. A few species
burrow or slip into holes to escape, while the boa constrictors
squeeze their enemies to death. Most snakes will not attack
man if unmolested, and they are generally as much frightened
as the person is. They charm birds, probably by paralyzing
them with fear, until they can creep up to and catch them.

1See Glossary.
16

242 BRANCH CHORDATA

The author attracted the attention of a charmed bird from its

gaze upon the snake and the bird immediately flew away.
The poison gland is an especially modified salivary gland, and

the poison fangs are maxillary teeth which have a furrow on the

ERYTHROLAMPRUS
VENUS TISSYUS!

taps fuiwws
(Vewor7z ous )

Fig. 198.—A case of mimicry, whcre a non-venomous species of snake re-
sembles & venomous one. (Romanes.)

anterior side, or the furrow is changed into a canal for the pas-
sage of the poison to the end of the fang, and henee to the
deepest. portion of the wound, where it poisons the blood of the
victim. Colton gives, as an antidote, a 10 per cent. solution of
ammonium carbonate taken internally.

LACERTILIA 243

There are many enemies of snakes. Prominent among them
are kites, hawks, shrikes, and other birds of prey, hogs, and
man.

Family Colu’bride includes all our common harmless snakes, as the
gartcr snake, ‘“‘ hoop snake,’ water snake, green snake, black snake or
blue racer, blowing viper, and others. They are all perfectly harmless,
though they make great pretensions with their terrifying appearance o1
bluff as to what they might do if you came too close.

Family Crotal’ide includes the rattlesnake, copperhead, and water
moccasin. All of these are poisonous and to be feared. The rattlesnake
gives warning, not so the deadly copperhead and water moccasin. Hap-
pily for man, civilization is driving out these dangerous reptiles.

Family Elap’ide is another family of venomous, chiefly East Indian,
snakes. There is one species (Fig. 198), the ‘bead snake” (E/laps ful/vius),
found from Virginia to Arkansas and south. Jordan describes it as “ jet
black with about seventeen broad crimson rings, each bordered with yellow
and spotted below with black, a yellow occipital band, tail with yellow
rings.” It is surely an example of warning colors which one will do well
to heed. A non-venomous species closely resembles it.

Library References.—Gadow’s ‘Amphibia and Reptiles ’’—Ophidia.
Read of snakes of other lands. Baskett and Ditmar’s ‘ Story of Am-
phibians and Reptiles’; Parker and Haswell on “ Reptilia.”

ORDER III. LACERTILIA

Lizards are reptiles with a distinct head, a snake-like body, a
tail generally longer than the body, and four short, nearly

Fig. 199.—Skeleton of a lizard: sp, Spinous processes, which in the tor-
toise are flattened into plates; r, ribs; s, shoulder-bone; a, upper arm; e,
elbow; fa, forearm; h, hip-bone; th, thigh-bone; k, knee; J, bones of the
leg; g, quadrate bone between upper and lower jaw. (From Holder.)

equal limbs, or no functional limbs, as in the so-called “ glass
snake” or “joint snake.” Their locomotion is aided by a

244 BRANCH CHORDATA

wriggling body motion. ‘‘ Two aortic branches, a left and a
right, survive in lizards.’

Lizards are very various in size, shape, color, and habitat.
Most of them are terrestrial, some burrow, some are seml-
aquatic, and still others are arboreal. They are generally cov-
ered with horny epidermal plates. Lizards shed their skin
entire.

The shoulder girdle and sternum are present. The “ flying
dragons ”’ of the Indo-Malayan countries have “a pair of wing-

Fig. 200.—Heloder’ma, a poisonous lizard. (From Holder's ‘ Zodlogy,”
American Book Co., Publishers.)

like membranes supported hy five or six elongated posterior
ribs, which they use as a parachute or fold up like a fan.”

Food.—Most lizards are insectivorous, eating small animals
also, but some are herbivorous, living upon buds, blossoms, and
tender leaves of plants.

Special Senses.—The eyes are usually provided with an
upper and a lower movable eyelid and with a transparent. nicti-
tating membrane. The tympanic membrane is situated in a
slight depression behind the eye. The tongue is free and both
jaws are armed with teeth. The mouth is not distensible.

1 Packard.

LACERTILIA 245

Multiplication —The egg-laying lizards deposit their eggs
in the sand or soil, except the Iguanidz, which lay them in hol-
low trees. Many lizards are viviparous. The male is larger
and more brightly colored than the female.

Lizards, as well as amphibians and snakes, find the ocean a
barrier to their progress, but lizard’s eggs have in some way been
carried to oceanic islands.

All are harmless except the Gila monster (Fig. 200), of the
Gila River region, which is the only poisonous lizard known. The
specimen in our laboratory is about 17 inches long, black, and
mottled with orange. Its only sound was a hiss, which it gave
when disturbed.

atch

Bk

i)

sfmeessine ES my SPURT co es, PBST ers

Fig. 201.—Glass snake (Opheosau'rus ventral'ts). The tail is twice the
length of the body, and breaks off at the slightest blow. When broken off
it grows again. (From Baskett and Ditmars, ‘‘The Story of the Amphib-
ians and Reptiles,” D. Appleton and Co., Publishers.)

The Skinks.—This family (Scin’cide) is represented by the cosmopolitan
blue-tailed lizard common east of the Rockies as far north as northern
Indiana, and by the ground lizard of the Southern States.

Cnémidéph’orus, a very little active brown lizard streaked with yellow
and black, is found from Connecticut to Virginia and from Wisconsin to
Mexico. In this family (Té’ide) there are over one hundred species dis-
tributed throughout South and Central America and the warmer parts of
North America.

The “‘glass snake” (Fig. 201), our representative of the family An’guide,
has a long brittle tail. Its brittleness is due to the fact that not only are

246 BRANCH CHORDATA

the caudal vertebrae loosely joined together, but each vertebra is provided
with a middle cartilaginous partition, so that it is easily separated. The
caudal vertebra of the Geckones and of most Lacerte break in the same
manner. It is one means of self defense, as the animal escapes with only
the loss of its tail. The popular notion of the pieces being collected again
is without foundation. When “ the tail is broken off,” and this is always
at this cartilaginous partition, ‘‘ the cells of the remaining half reproduce a

Fig. 202.—An’olis or American chameleon (Anolis principalis). Al-
though the general color of the animal beneath is white, the upper parts
may quickly assume hues varying from a vivid emerald green to a dark
iridescent bronze color. (From Baskett and Ditmars, ‘“‘ The Story of the
Amphibians and Reptiles,” D. Appleton and Co., Publishers.)

new tail.”’ This new tail, says Gadow, is only a ‘‘ sham tail,’’ since it does
not consist of a series of vertebric, but of “a non-segmented rod or tube of
fibrocartilage.”’

This lizard cannot climb, and does not like the water, so it’ may be said
to be entircly terrestrial. I1s food consists of ‘ snails, insects, worms, mice,
small lizards, birds, and vipers.” It shakes its prey until the victim is
stunned, then chews and swallows it. It does not bite when caught, but
winds about the wrist and emits a stinking discharge. It hides among the

LACERTILIA 247

leaves and in the sand under bushes. This species lays eggs, though some
of its family are viviparous. It hides its eggs under moss and leaves and
the young mature very slowly, taking several years to reach maturity.

The American Chameleon and its Relatives.—Our very interesting lit-
tle lizard (An’olis) (Fig. 202) of Florida and the Carolinas is commonly
called a “chameleon,” but the real chameleon is a native of Africa. The

‘green chameleon ” (Anolis) has the power of suddenly and voluntarily
changing its color to adapt itself to its environment. Experiments upon
this animal in our laboratory proved that it changes color more rapidly
when placed upon objects with natural colors than it does upon artificially
colored ones. It is arboreal and insectivorous. The males have ‘ large
gular sacs which can be distended by the hyoid bones.” These sacs are
white, with occasional red lines and spots, but when inflated they become
crimson. The Anolis is 5 or 6 inches long.

Another member of this family is our little Swift, common in the forests
and fence corners of the United States as far north as Michigan. It delights
to lie basking in the sun, but disappears quickly when disturbed.

Fig. 203.—The “horned toad” (Phrynoso’ma blainvillei). The spiny cov-
ering repels many enemies. (From Jordan and Kellogg, ‘‘ Animal Life,”
D. Appleton and Co., Publishers.)

Another member is the very interesting little lizard called the “ horned
toad”? (Fig. 203), Phrynoso’ma, found in the dry regions of the Southwestern
States. The body is oval in form, rather flat and broad, with a short conical
tail. It is covered with irregularly shaped keeled or spiny scales, the head
being ‘‘ bordered posteriorly with osseous spines.” The small eyes are each
protected by a ridge running backward above them. The ventral side of
the author’s pet ‘“ horned toad,” a specimen from southeast Kansas, is
yellowish in color, with a number of brown spots dotted over it. The scales
are small and regular. The general color of the animal, dorsally, is grayish
or yellowish brown, affording, together with its irregular and roughened sur-
face, an excellent protective resemblance to the sand in the desert regions,
in which it likes to sink until the spines of the head alone stick out. Thus
some species, at any rate, lie concealed through the night and on cloudy
days. They are liveliest in the middle of the day and delight in the hot sun.
When alarmed they shut their eyes and lie flat on the sand. Their food
is insects, which they catch as toads do with their tongues, which are smooth,
short, and scarcely at all notched, and can be thrust out a short distance

248 BRANCH CHORDATA

only, perhaps not over } inch. ‘“ Horned toads ’’ will endure long fasts.
They hibernate in winter. All species are viviparous and the young at
one litter number seven or eight.

Another Iguana (tuberculata), of South and Central America and the
West Indies, is sometimes 5 or 6 feet long and weighs nearly 30 pounds.
It spends much of its time in trees, but when alarmed plunges into the
water below it. It lays about two dozen eggs in a hole in the side of the
bank. The flesh of these animals is much prized for food by the natives.

The Monitors.—The one genus (Var’anus) of this family (Varan’ide)
consists of about thirty species. They are found in Africa, but not in
Madagascar, in Australia, and in Southern Asia. They have long forked
extensible tongues. They are large, attaining the length of 4 or 5, or even
6 feet. Some are found in desert or dry regions, while others are semi-
aquatic. The natives of some regions use the flesh of the monitors for
food. The monitors are rapacious, devouring any animals which they
can get. The monitor of the Nile is a great enemy of the crocodile, de-
vouring great numbers of its eggs.

Library Work.—ce Gadow or other large works on reptiles
for an extended description of Lacertilia of the tropical regions.
The ‘“ Flying Dragon” and other interesting forms are well
worth your study. Baskett and Ditmar’s ‘“‘ Story of Amphib-
ians and Reptiles ”’ relates many interesting facts in a simple,
yet instructive manner, also, Hornaday’s ‘‘ American Natural
History.” Do not fail to read the larger works. Get beyond
mere text-book study of these wonderful forms in this and other
lands. Broaden your own horizon.

ORDER IV. CHELONIA

Turtles vary in size from a few inches in length to 6 or more
feet in some marine forms. The turtles of to-day are small as
compared with some extinct forms. They vary in weight from
a few ounces to over 1000 pounds. There are marine, fresh-
water, and land forms, while the ‘‘ gophers ” of the South bur-
row in the ground.

Skeleton.—Turtles are easily recognized by their shell or
exoskeleton. The dorsal portion of the shell is called the cara-
pace, and the ventral portion the plastron. The covering of this
shell consists of horny epidermal plates. These are thin, and
when pulled off reveal the bony shields beneath.

The bony carapace (Figs. 204, 205) is composed of the spines of
the dorsal vertebra, flattened, the ribs broadened out and joined
to each other by sutures, also to the outer marginal row of

CHELONIA 249

Fig. 204.—Bony carapace of turtle with epidermal plates removed to reveal
bony shield with portion missing. Dorsal view.

Fig. 205.—Bony carapace of turtle. Notice how the ribs are broadened and
joined by sutures. Ventral view.

250 BRANCH CHORDATA

dermal bones, all fused into one bony carapace which is covered
by epidermal plates. The plastron consists of epidermal plates
underlaid with bony shields. The head, limbs, and tail may be
more or less withdrawn under the carapace for protection; in
some forms so completely that there is no part of the turtle
visible outside of the shell.

They have four short, strong, clawed, pentadactyle limbs, or,
in the case of some marine forms, flippers. The marine paddle-
limbed forms are usually designated as turtles, and those with
walking limbs as tortoises.

The bones of the head are firmly united. The jaws are
toothless, but are inclosed in sharp horny beaks, with which
they seize and crush their prey and then swallow it whole.
The pectoral arch is a ‘“triradiate structure, of which the

Fig. 206.—Skeleton of snapping-turtle with portion of carapace sawed off
to show interior. Cleaned and mounted by students; (much reduced.)

most ventral and posterior ruy ending in a free extremity is
the coracoid, while the other two are the procoracoid and the
scapula with the suprascapula, which are fused at their glenoid
ends.”! The pelvis is strong, consisting on each side of the
pubis, the ischium, and the ilium. These meet at the articular
surface of the hind limb. The vertebre are few as compared
with those of the snake. Those of the neck fit into one another
with ball-and-socket-joint. There is no trace of a sternum or of
sternal ribs.

Digestive System.—The tongue is usually soft and wide and
not extensible. The esophagus is covered with ‘ conical pro-
jections pointing toward the stomach.” There is no cecum.

Food.—Some species are carnivorous, some are herbivorous,

' Parker and Haswell, vol. ii, p. 329.

CHELONIA 251

while others are omnivorous. Predacious species probably
hie in wait for their prey.

The respiration is unique. The large spongy lungs reach to
the pelvis. In breathing the neck and limbs act like pistons in
being drawn in and out. The throat is alternately inflated and
emptied by the hyoidean apparatus when the neck is stretched
out, thus the air is swallowed or pumped into the lungs. Since
the lungs are so roomy and the animals poikilothermal, most
turtles can live for a long time without breathing, sometimes
remaining under water for hours or even days.

Special Senses.—Their eyes, though comparatively small,
are their most highly developed sense organ. They are situ-
ated far forward on the head and protected by two lids and a
nictitating membrane. The nostrils are terminal; thus by ex-
posing a minimum portion of the head above water they are
able to breathe and see what is going on about them, compara-
tively free from danger. The sense of smell is well developed,
many species showing a choice of certain kinds of food which
they distinguish by smell. The sense of hearing is not well
developed. That they distinguish sounds is evident from
their voice, which Gadow declares is very tiny and piping during
the pairing season. Some species, at least, snap their jaws
together when angry, and when the head and limbs are with-
drawn they make a hissing sound. Holder says the male
“ elephant turtle ’’ of the Galapagos Islands “‘ utters a hoarse
croak or bellow during the breeding season.”’ They are fright-
ened by noise. The tympanic membrane in most water forms
is thin and quite exposed. In land tortoises it is often thick and
covered with the skin. Turtles, contrary to the notion of small
boys, are very sensitive to the touch, both upon the shell and
upon the soft parts.

Multiplication Turtles lay their eggs at night in the sand,
cover them carefully, and leave them for the heat of the sun-
warmed sand to hatch.

The young are like the adult in general, but differ somewhat
in color.

Enemies and Defense.—They are preyed upon by carnivo-
rous birds, fishes, alligators, and by men. They defend them-
selves by closing up their shell, as the box turtle; by snapping

252 BRANCH CHORDATA

and scratching, as the snapping turtle; by swimming away or
by hiding in the mud, and thus escaping by the protective
resemblance. They hibernate in winter in this latitude.

The leathery shelled sea-turtle (Sphar’gis coriacea) is the largest of all
recent turtles. It is from 6 to S feet long, and of a dark brown color, and
may weigh 500 pounds or more. It is widely distributed in the tropical
seas, but it is abundant nowhere. The dorsal and ventral portions of the
weak bony shell are continuous. It is buried under a layer of fat which
yields “ about a pint of oil to each square foot.’ The sea-turtles have
long flat triangular flippers without tocs or claws. The front flippers are
long. Its flesh is not edible.

Hard-shelled Sea-turtles (Chelon’idew).—In this group is found the green
turtle, one of the most widely distributed of the Atlantic turtles. It is
found from Long Island to Cuba and south to Brazil and also in the
Indian Ocean. Its flesh is prized for food. It varies in weight from 50 to
500 pounds.

The tortoise-shell turtle, from which is obtained the valuable tortoise
shell, has its upper jaw terminated in a strongly hooked beak. Until the
animal is very old the shields overlap one another from before backward.
The scales are clear yellowish horn beautifully mottled with black and
brown. These turtles do not reach the size of the green turtle; the largest
one on record, says Gadow, is 34 inches long. They range over all the
opie and subtropical seas, being found occasionally around the Bahama

slands.

The soft-shelled turtles (Trionych’ida) are of wide distribution both in
time and space. The shell is very flat and almost circular. It is imper-
fectly ossified both above and below, and terminates at the edges in thin
plates of leathery skin. When properly cooked the shell is tasty.2. These
turtles are brown, mottled with black above and clear white below, and
weigh from 20 to 30 pounds.

The Snapping Terrapins (Chelyd’ridie) —This family includes the alli-
gator snapper, the largest North American terrapin of the Gulf States, and
our common “snapping turtle” found everywhere in fresh-water ponds
and streams. The snapping terrapin has very powerful strongly hooked
jaws, a Idng tail with a crest. of bony compressed tubercles, and a small
cross-shaped plastron. It scldom leaves the water. It is carnivorous, very
voracious, and savage. It is destructive to fishes and water birds.

The Smooth-shelled Terrapins (Hmyd'idir).—The diamond-back terra-
pin is found (or was until so much hunted for food) in salt marshes from
New York to Teaxs. It varies in color from greenish to dark olive or black
(rarely). It is small, one weighing a pound is considered large. It is
regarded as the choicest variety for a terrapin stew. It is said that there
are several “ terrapin farms” in the South in which this turtle is being
reared for the market. Unless some such provision is made they will soon
be exterminated.

The painted terrapin (Chry’semys pic'ta) is common in most. regions east
of the Mississippi. The shell is much depressed. The plates of the eara-
pace in Chrysemys picta are greenish black edged with yellow, those about

1 Hornaday, p. 331.
2 Thid.

CROCODILIA 253

the margin being conspicuously marked with red. The plastron is yellow,
blotched with brown. There are markings of yellow and red upon the
sides, neck, limbs, and tail, a pair of bright yellow patches behind the eyes,
and a smaller pair on the back of the head. The toes are strong and broadly
webbed. They are especially fond of insects and worms. They are very
shy and active. Chrysemys marginata is a western form.

The common box-turtle (Ctstw’do), a terrestrial member of this group, is
built for life on land. Its carapace is high and it can withdraw its head,
legs, and tail within it. Across the center of the plastron is a double
hinge, so that when disturbed it completely shuts itself in the box, and
nothing short of injuring the shell can harm it. One was once subjected
to a strong dose of chloroform in our tight-covered “ killing jar”’ for two
hours with little or no effect, so tightly was it shut up in its box. It is surely
a good illustration of special adaptation to environment. Since it cannot
run, like the rabbit, nor swim, like its relatives of the streams, it closes up
its house and remains motionless. It is found from New York to Missouri
and southward.

The musk terrapin (.4romoch’elys odora’lus), a representative of the family
Kinosternide, is a small fresh-water specimen which has a strong, musky
characteristic odor. Its food consists of aquatic insects, small fishes, and
worms.

The Land Tortoises (Testudin'iid@).—The giant tortoise, which inhabits
the Galapagos Islands and two islands of the Indian Ocean, is the only sur-
vivor of a race of giant tortoises of the Reptilian Age. A specimen once
in the New York Zodélogical Garden weighed 310 pounds, and was estimated
to be four hundred years old.

Almost every island of the Galapagos group has had or has
its own peculiar form of tortoise. How they got to these islands
or where they came from it is impossible to say definitely.
They could not have migrated, since land tortoises are easily
drowned, and anyway, “ there are now none of their kind on the
continents of Asia, Africa, or South America.’? So it is as-
sumed that they are descendants of tortoises once populating
the land which, except these islands, now lies below the Indian
Ocean.

Our native species of this family is the Gopher tortoise, found
in the pine barrens of the Southern States.

ORDER V. CROCODILIA

Crocodiles and alligators are the largest of living reptiles,
some of the largest crocodiles attaining a length of 30 feet.
They are covered with horny plates or scales.

The head is remarkable for its powerful jaws, whose enor-
mous gape enables the animal to seize and crush its prey.

1 Gadow.

254 BRANCH CHORDATA

The eyes, nostrils, and ears are on top of the head. While
exposing only a small part of its body, it can see and hear well
the approach of an enemy. ‘“‘ Crocodiles are the only reptiles
whose nostrils open in the throat behind the palate instead of
directly into the mouth cavity. This enables the crocodile to
drown its victim without drowning itself, for by keeping its
snout above water it can breathe with its mouth wide open.’
When under water the nostrils are closed by a valve.

Limbs and Tail.—Their four limbs are stout, short, and
powerful. The tail is strong and compressed. It aids the
animal in locomotion, in self-defense, and in knocking its prey
off the bank into the water, where it is seized and held under
water until strangled to death.

Habits.—They are aquatic and nocturnal in activity, feed-
ing at night upon fishes, birds, mammals, and whatever they can
capture. Hornaday describes how an alligator dismembered
its victim. It seized the prey by one leg, whirled itself round and
round till the leg was twisted off. He saw another shake a com-
panion until the skin of its back was torn in two.

They hibernate in temperate regions, and estivate or migrate
in tropical regions when drought overtakes them.

The Florida crocodile digs burrows in the sandy banks. The
entrances are wholly or partly under water. At the farther end
the burrow is wide enough for the crocodile to turn round in.

They lay their large white eggs in the sand away from the
water, or build rude nests or mounds in which they deposit their
eggs in layers and watch and defend them until the voung are
hatched.

The ga’vial of India (Fig. 207) is long, and slender snouted. The animal
may reach a length of 20 feet, but is harmless to man, being a fish-eater.

Alligators.—The male alligator may reach a length of 12 feet and the
female that of 8. The male has a heavier and more powerful head and is
the more brilliantly colored during the breeding season. The large nest is
built by the female on the bank of a stream or pool. The young are active
and shift for themselves. The alligator finds its northern limit in North
Carolina, about 35° North Latitude. From here south they abound near
the mouths of creeks and rivers as far south as the Rio Grande. They
ascend the Mississippi to 33° 50’ North Latitude, or to the mouth of the
Red River.

There is a small species of alligator in China. It is about 6 feet long, of
a grecnish black color dotted with yellow.

1 Dodge. p. 476.

CROCODILIA 250

Fig. 207 —Gavial (Gavia'lis gange’tica). (From Baskett and Ditmars,
“The Story of the Amphibians and Reptiles,’ D. Appleton and Co.,
Publishers.)

Fig. 208.—Crocodiles. (From Baskett and Ditmars, ‘ The Story of the
Amphibians and Reptiles,” D. Appleton and Co., Publishers.)

The caiman, of Central and South America and the West Indies, is some-
thing like our alligators and may reach a length of from 6 to 20 feet.

The crocodile (Fig. 208) of the Nile and Madagascar and Asia is the
largest of the order, sometimes reaching a length of over 20 feet. Hornaday
says four species of crocodiles are found in America, and that. only three of
the nineteen species of crocodiles are dangerous to man, the most dangerous

256 BRANCH CHORDATA

of these being the “ salt-water crocodile” of the Malay Peninsula. The
American crocodile and the alligator are not dangerous to man.

“The Florida crocodile is the only crocodile which inhabits a country
that is visited by killing frosts.”! It is most abundant in low wet lands and
shallow water, where the mainland sinks into the gulf. There is a Cuban
crocodile and two South American species.

Distribution of Reptiles—The animals of this class are
generally tropical and subtropical. Snakes are said to extend
farther north in America than do lizards. In Europe snakes are
not found north of 60°, while lizards are sometimes found farther
north or at an elevation of ten thousand feet.

Lizards are the most numerous of reptiles at the present time,
and are found in all except the cireumpolar regions.

Chelonia are also widely distributed in the tropical and tem-
perate regions.

The alligators occur only in North America and in China, and
the Caimans are found only in Central and South America.
Crocodiles are distributed over Africa, southern Asia, northern
Australia, and tropical America, there being one species in
Florida.

True reptiles are known to have existed in the Permian Pe-
riod. Indeed, there was such a “variegated reptilian fauna” that
it is believed their ancestors must have lived in the Carboniferous
Period. One of the Permian orders (Theromor'pha) exhibits cer-
tain strong points of resemblance to the earliest amphibians and
other points of resemblance to the lower animals. They have
been found in rocks of the Permian and Triassic Periods, but in
none of the more recent formations. These fossils have been
found in Texas, South America, Europe, Africa, and India.

Lizard-like forms (Sauroptery'gia) existed in the Cretaceous
and Triassic and possibly in the Permian periods. They varied
from small forms up to those of 40 feet in length. A fish-like
form (Ichthyoptery'gia), varying from 30 to 40 feet in length, ex-
isted from the upper Triassic to the upper Cretaceous periods.
In the Triassic were also forms allied to the crocodile.

One of the most characteristic of the Mesozoic orders of
reptiles was the Dinosauria, many of which existed in the Triassic
Period. Some were herbivorous, others carnivorous. Some

1 Hornaday.

CROCODILIA 257

walked on all fours, others occasionally or habitually walked
upright, after the manner of birds, with which they had many
structural features in common. Their size was so great that the
footprints measured from 14 to 18 inches. The length was
sometimes 60 to 70 feet and the height nearly 20 feet.

The earliest turtles were found in the Triassic of Europe.
True lizards appeared and turtles abounded in the Jurassic.
The Pterosau’ria appeared in the Jurassic. They had toothed
jaws and were winged like a bat. The spread of wings did not
exceed 3 feet. In the Cretaceous Period the spread of wings was
20 feet. Gigantic carnivorous marine lizards swarmed on the
Atlantic and Gulf coasts and in the interior seas of that time.

In the tertiary period reptilian life shows a great change, the
animals being neither so large nor so varied.

All the fossil snakes, except one found in the cretaceous, have
been found in the tertiary period.

It is plain to be seen why the Mesozoic Era is called the “age
of reptiles,’ and how closely related the reptiles are to both
amphibians and birds. They differ from amphibians in having
bodies covered with scales, in having but one occipital condyle,
in having the embryonic membranes, the amnion and allantois;
in Crocodilia, in having a four-chambered heart; in never having
gills, and in never having a tadpole stage. They differ from birds
in having scales, but never feathers, and in the circulation (being
poikilothermal). If we include the extinct forms, there will be
found many points of similarity between reptiles and birds.
Hence it is believed that amphibians, reptiles, and birds have a
common ancestry.

Economic Importance.—As has been mentioned, many rep-
tiles are used for food. The skins of rattlesnakes and boas are
made into bags, cases, boots, saddle cloth, ete. The oil of the
rattlesnake and boas is valuable, and that of the copperhead is
used in medicine. The scales of the tortoise-shell turtle are
valued for combs and ornaments, and the oil from its eggs is
used in dressing leather. From alligators we get valuable
leather, oil, and musk. The teeth, flesh, hide, and oil of croco-
diles are valued.

Most of our common forms are not dangerous to man, and,

1 Parker and Haswell.
17

258 BRANCH CHORDATA

any way, will not attack him if unmolested. A few forms of
snakes and crocodiles are dangerous to man.

Important Biologic Facts——The embryonic membranes, the
amnion and the allantois, first appear in this class. Respiration
is by lungs. True nostrils appear. The heart is four cham-
bered in Crocodilia.

Classification.—
Order. Examples.
I. Rhynchocepha’lia. Sphenodon punctatum.
II. Ophid’ia. Snakes.
Ill. Lacertil’ia. Lizards.
IV. Chéld’nia. Turtles.
V. Crécodil’ia. Crocodiles, alligators.

CLASS V. AVES

“T have considered the birds,
And I find their life good,
And better, the better understood.”
(McDonald.)

In existing forms, birds are feathered chordates having no
teeth, but from paleontology we learn that some of the fossil
birds (Figs. 209-212), as the Archwop’teryx (Fig. 212), of the
Jurassic Period, had teeth and a long vertebrated tail.

Birds have several characteristics in common with reptiles,
among which are the large eggs, the lack of a complete dia-
phragm, the quadrate bone connecting the lower jaw with the
skull, and the single occipital condyle. It is believed that in the
early stages of their development birds floated in the air by
means of a patagiwm, or wing membrane, and that even “‘feath-
ers were used at first as a means of sailing down” after having
crawled up to some height by the use of claws on the “‘fingers,”’
vestiges of which are yet shown by many birds, such as the
turkey, the vulture, certain ostriches, swans, thrushes, and
young gallinules, which have claws variously located on the
wing tips.

Covering.—The lower part of the legs is covered with hard,
reptile-like scales, or epidermal shields, for protection. The
beak and claws are also horny epidermal structures.

AVES 259

The skin of a bird is thin and the body is not uniformly
covered with feathers (Fig. 213). There are many bare spots,
as may be readily seen by turning back the feathers on the neck
or breast. The bare spaces, apteria, are concealed by the over-
lapping feathers. Note where the feathers grow. These spaces
are called pteryle, from two Greek words meaning ‘feather
forest.”

Feathers are homologous with scales, as ‘“‘the feather may be
regarded as a cornified outgrowth from the skin, which has arisen

Fig. 209.—Ichthyor'nis victor, X 4. Fig. 210.— Hesperor’nis regal’is, x x.
(Restored by Marsh.) (Restored by Marsh.)

on a papilla of the derma.”! A large wing feather, for example,
is made up of the central stalk and the expanded part, or vane.
The hollow portion of the stalk nearest the body is the quill,
and the remaining part, the rachis or shaft. The vane is com-
posed of side branches or barbs, the barbs of side branchlets or
barbules, which are provided with hooks. The hooks of one
barbule interlock with those of the next and thus hold the parts
of the vane together. In down feathers the hooks are lacking.
' Hertwig.

260 BRANCH CHORDATA

The large feathers on the wing and tail are called quills; the
similar but smaller ones on the body, the contour or outline
feathers; those without barbs, down; and the hair-like ones, the
filoplumes or pin-feathers. These different kinds have various

Fig. 211.—Dinor'nis gigantens, * }5. (From a photograph of a skeleton in
Christchurch Museum, New Zealand.)

uses. Can the student see the advantage to the bird of each
kind of feather? What use does man make of the different kinds
of feathers?

“Since the feathers are not only for protection, but give to
most birds the power of prolonged flight, they predict a special

AVES 261

mode of life. The character of the skeleton, the respiratory
organs, and, in part, the sense organs and brain are connected
with the powers of flight.’”!

Variation in Plumage.—The changing of the feathers and the
colors of birds is very little understood. The nestling plumage
may be so meager that we speak of the young as naked, but the
precocial forms, as the grouse, snipes, and ducks, have a thick
covering of down. This is followed by what is known as the

Al Ly i} iJ
if ZL, I
“TAWA YF

Fig. 212.—A, Archeopteryx macura, restored (Fowler). B, Section of the
tail (after Owen). (Romanes.)

first plumage, which appears more quickly upon the naked than
upon the down-covered young and which may be unlike that
of either parent. In most land birds this is soon followed by
the immature plumage to be worn during the winter. This
plumage may be like that of the adult parent of the same sex,
or it may be that both immature males and females may resemble
the adult female, or they may be unlike either parent. In the

1 Hertwig, p. 604.

262 BRANCH CHORDATA

first, second, or even the third spring the plumage becomes like
that of the adult.

The time of molting varies not only among different species,
but often among different individuals of the same species, ac-
cording to sex, age, and physical conditions. All birds molt after
the nesting season. Some birds lose a few of the body feathers
in the next spring before the nesting season, while many lose the
body feathers, but not those of the wing and tail. Some change

Fig. 213.—Pteryle and apteria of Gallus bankiva (Nitzsch): a, Ventral
side; b, dorsal side.

color by wearing off the fringes of the feather tips, and others
at this season are adorned with special nuptial plumes,! such as
the aigrette of the heron, for which these birds have been so
slaughtered.

There are no periodic molts of the skin, as in reptiles, but the
horny layer of the integument undergoes a constant renewal, as
in mammals. Some penguins, it is said, ‘exhibit the old rep-

1 Chapman, “ Bird Life,” p. 38.

AVES 263

tilian habit of shedding theirs in great flakes, with feathers
attached.”!

General Structure.—The skull (Fig. 214) is thin; the bill or
horny beak varies much according to its use; and there is, as in
reptiles, only one occipital condyle. The neck is long and flex-
ible. In different kinds of birds, the number of neck vertebrae
varies from eight to twenty-four.

The wings are adapted for flight in our birds. While the
ostrich cannot fly, its rudimentary wings are compensated for
by its very strong legs, which are adapted for rapid running.
No other animal has wings of the same structure as a bird’s.
The characteristic structure of the wing-bones is the hand. It
is comparable with the human hand.

Fig. 214.—Skull of parrot: 22, Premaxillary bone ensheathed in horn;
15, nasal bones; v, mandible, the end sheathed with horn; /, malosquamosal
zygomatic style or maxillojugal bar; g, postfrontal bone; 0, lacrimal
bone; n, nostril, showing also the articulation of the nasopremaxillary
bone; e, quadrate bone; m, orbit; 1, occipital bone. (After Owen.)

The legs and feet (Fig. 215) of birds are adapted for running,
scratching, swimming, or perching. Note the position of the
thigh (femur) on the side of a bird. Do you see any advantage
of such a position? Distally the femur or thigh is joined to the
tibiotarsus and the fibula, which is found partially united with the
tibiotarsus. The proximal row of tarsal bones unites with the
distal end of the tibia, hence the name tzbiotarsus or ‘“drum-
stick” in the chicken. The distal row of tarsal bones unites with
the metatarsal bones to form the tarsometatarsus or simply the
tarsus, which bears the usually four-clawed toes. One toe is
generally directed backward and three forward.

Where is the knee in the bird? The ankle? Do you see any

1 Baskett, ‘ Story of the Birds,” p. 33.

264 BRANCH CHORDATA

advantage in this arrangement? Why do they differ from the
structure and arrangement in the leg of man?

The body skeleton (Fig. 216) is strong, light, and flexible, as it
must be for flight. Note how firmly the vertebre are joined in

Sect anes

Bee tare
Lies

Fig. 215.—The most important forms of birds’ feet (b, c, d, f, x, from the
régne animal): a, Pes adhamans of Cypselus apus; b, P. scansorius of Picus
capensis; c, P. ambulatorius of Phasianus colchicus; d, P. fissus of Turdus
torquatus; e, P. gressorius of Aleedo ispida; f, P. insidens of Falco biarmicus;
qh BP. colligatus of Mycteria senegalensis; h, P. cursorius of Struthio camelus;
z, P. palmatus of Aferqus merganser; k, P. semipalmatus of Recurvirostra
avocelta; l, P. fissipalmatus of Podiceps cristatus; m, P. lobatus of Fudica
atra; n, P. steganus of Phacton ethercus. (After Claus.)

the back. Note also the very short bony tail, consisting of a
few vertebrae fused into the pygostyle, which supports the tail
feathers. The oil gland is situated near the pygostyle and from
it birds get the oil for their feathers. Note also that the sternum

AVES 265

is keeled in our birds, while the keel is lacking in the ostrich.
The keel or carina is a basis of classification. Birds with the
keel poorly or not at all developed are called Raiv’te, or raft-like
birds, while the keeled birds are called Carina’te, which group
contains our native American birds.

The shoulder-girdle is a peculiar device of flying creatures.
It consists of the scapula, coracoid process, and the V-shaped

a iG

Fig. 216.—Skeleton of a sparrow: g, Quadrate bone, peculiar to reptiles
and birds and some amphibia; b, breast-bone; m, merry-thought or collar-
bone; c, coracoid bone, over which the tendon works to pull up the wing;
p, plowshare-bone, on which the tail grows. Wing-bones: a, Upper-arm;
e, elbow; fa, fore-arm; w, wrist; ¢, thumb; ha, hand. Leg-bones: th, Thigh-
bone; k, knee; J, lower part of leg; h, heel; f, foot. (From Holder, Amer-
ican Book Co., Publishers.)

clavicle, or ‘‘wish-bone.” The pelvic girdle consists of three
paired bones, iliwm, tschium, and os pubis, which unite at the
cup or acetabulum, which holds the head of the femur.

A careful study of the skeleton of a bird shows its marvelous
adaptation to its uses. It must be strong to support the great
muscles of flight and to protect the viscera, while it must be light
and flexible for the purpose of aérial locomotion.

266 BRANCH CHORDATA

The Digestive System.—The mouth is devoid of teeth in exist-
ing birds. Extinct birds (see Figs. 209 and 210) had teeth (see
Geology). Can the student see any reason why birds have lost
their teeth? The beak (Fig. 217) is very strong in birds of
prey, such as the eagle and hawk. The mouth opens into the

Fig. 217.—Forms of beaks (a, b, c, d, k, after Naumann; g, 7, m, 0, régne
animal; 1, from Brehm): a, Phenicoplerus antiquorum; b, Platalea leucorodia;
c, Emberiza citrinella; d, Turdus cyanus; ce, Falco candicans; f, Mergus
merganser; g, Pelecanus perspicillatus; h, Recurvirostra avocetta; t, Rhyn-
chops nigra; k, Columba ria; l, Balaniceps rex; m, Anastomos coromande-
lianus; n, Pleroglossus discolor; 0, Miycteria senegalensis; p, Falcinellies
igneus; q, Cypselus apus. (After Claus.)

esophagus, which opens into the large crop, in which the bird rap-
idly stores its food, which is passed on to the glandular stomach
or proventriculus. It is then passed to the muscular gizzard,
where with the aid of gravel and other hard substances, the food
is ground fine. The spleen is a small, red ovoid body at the right

AVES 267

of the proventriculus. Following the gizzard is the duodenum.
The pancreas is in a loop of the duodenum and pours its secre-
tion into it. The large liver pours its bile into the duodenum.
The ileum continues from the duodenum to the large, straight
intestine, the rectum. The junction is marked by long, blind
pouches or ceca. The large intestine ends in an enlargement
called the cloaca, or sewer, because it receives the undigested
food, the excretions of various organs, and the eggs, all of which
pass out by one external opening.

Circulatory System.—Circulation is complete. The heart is
large and composed of two auricles and two ventricles. The
right aortic arch persists in birds, while the left persists in man.
The circulation is double, pulmonary and systemic. The sep-
tum is complete between the ventricles, thus keeping the impure
blood (venous) from the pure blood (arterial).

The Respiratory System.—The pharynx opens by the glottis
into the trachea, which divides and sends ramifying branches into
the lungs. The lungs connect with the system of air-sacs which
aid the bird in flight. ‘‘Usually five pairs of these sacs are pres-
ent, largely in the ccelom, but extending in between the muscles
(breast and axillary region) and also into the bones.’”! The
syrinx or voice-box is at the junction of the bronchial tubes
and the trachea, where they enlarge to form it. This syrinx
is especially well-developed in smging birds.

Many of the bones are hollow and filled with air. Thus is
the inspired air distributed over the body, so that the aération of
the blood is not confined to the limited area of an ordinary organ
of respiration. The bird is a very warm-blooded animal, and to
keep up its heat it must use oxygen rapidly. This it does by its
rapid breathing, which may be at the rate of sixty per minute.
The temperature of birds is from 100° to 110° F., while in man
the temperature is 98.6° F. The temperature is also kept up by
the non-conducting feathers and by the absence of skin glands,
with the exception of the oil gland at the base of the tail.

In the absence of a diaphragm, expiration is effected by the
drawing of the sternum toward the spinal column and the bend-
ing of the hinged ribs. Inspiration is effected by the straighten-
ing of the ribs brought about by relaxing the muscles. Thus the

1 Hertwig.

268 BRANCH CHORDATA

lungs, which are attached to the ribs, are alternately enlarged
and contracted.

The Excretory System.—With each expiration the lungs
excrete carbon dioxid and other waste products. The kidneys
are dark-colored, paired organs lying in the pelvic region close
against the back. They open into the cloaca by the ureters.

The Reproductive System.—Anterior to the kidneys are the
reproductive organs, which open into the cloaca. Multiplica-
tion is by eggs, which are noted for their very large size. The
egg begins in the left ovary, the right ovary not being developed.

Fig. 218.—Diagrammatic longitudinal section through an undeveloped
hen’s egg: Bl, Germinal disk; GD, yellow yolk; WD, white yolk; DM,
vitelline membrane; EW, albumen; Ch, chalazw; 8, shell membrane; AS,
calcareous shell; LR, air-chamber. (After Allen Thompson.)

It passes into the oviduct, where it is fertilized. As it passes on
down this duct it acquires the yolk, the white, the linings, and
the shell from glands that secrete these essential parts of the ege
(Fig. 218). The birds are devcloped by the large amount of
food within the shell.

Incubation, or sitting upon the eggs for a definite period of
time, is peculiar to birds, though the python is said to coil upon
its eggs. The number of eggs in a clutch varies from one to a
score or more. Some birds, like the pigeon, are monogamous,
choosing one mate for life, but many are polygamous, like the
barnyard fowls. It is said that most pretty birds are flirts.

AVES 269

The young of some birds are altricial (Fig. 219) and must be
cared for and fed by the parent or parents; while others, like

il

|

Fig. 219.—The altricial nestlings of the blue jay (Cyanocit'ta crista’ta).
(From Jordan and Kellogg, “‘ Animal Life,” D. Appleton and Co., Publish-
ers.)

the quail, are precocial and are able to feed and care for them-
selves as soon as_ hatched.

The nests of birds vary much according to the habitat of the
bird and the material available (Fig. 220). Birds, like men, use
the material they find about them. Ground birds use the ma-

270 BRANCH CHORDATA

terial they find on the ground, while the arboreal forms more
often use small twigs for their nests, which they sometimes line
with finer material, such as strings and hairs. The woodpecker
uses no material but the tiny chips he has made in digging the
hole. The swift glues together the twigs of its nest by a sticky
saliva. According to the manner in which they construct their
nests, birds have been variously styled weavers, tailors (Fig.
221), carpenters, or masons, and their tools vary according to

Fig. 220.—Brown pelican and nest in young cabbage palmetto. (Photo-
graph by Frank M. Chapman.) (Y. B. U. 8. Dept. of Agricul.)

the work to be done, or vice versa. Sometimes both sexes build
the nest, or one collects the material and the other arranges it.
In other cases the male sits by and sings, leaving the building
to his mate. The position of the nest varies. It may be placed
upon the ground, like that of the quail, or on a rock, like the
penguin’s, or suspended far out on the swaying branches, like
the delicate hanging nest of the oriole (Fig. 222). The object
of the position, of course, is for protection. One must observe

AVES 271

how well birds are protected by their colors, especially the fe-
male birds at nesting time.

The Nervous System and Special Senses.—The brain (Fig.
223) of birds is larger and more highly developed than that of
reptiles. The cerebrum and cerebellum are larger. The cere-
brum is smooth, but the cerebellum is convoluted transversely.

Fig. 221.—Tailor-bird (Orthot’omus suto’rius) and nest. (From Jordan
and Kellogg, ‘“‘ Animal Life,” D. Appleton & Co., publishers.)

The eyes of the birdare large, tomeet the demands of far vision
in flight. There are two movable eyelids and a third membrane
called the nictitating membrane, which the bird can draw over
the eye by a peculiar muscular arrangement. This membrane
protects the eye from too bright light (Fig. 196). The pecten,
“a, comb-shaped growth of the coroid into the vitreous body,”
is a peculiar avian characteristic. The avian eye is character-
ized net only by the sharpness of vision consequent upon the

272 BRANCH CHORDATA

EN 2

Fig. 222.—Baltimore orioles and nest; the male in upper left-hand corner
of figure. (From Jordan and Kellogg, ‘‘ Animal Life,”’ D. Appleton & Co.,
publishers. )

large size and complicated structure of the retina, but also by the
highly developed power of accommodation, and by the great mo-
bility of the muscular iris in the dilation and contraction of the
pupil.

The ear is well developed. There is no external ear, but the
opening to the tympanum is concealed by feathers posterior to
the eye. The ear has three semicircular canals, the dilated
cochlea, and a Eustachian tube extending to the mouth from
each ear.

Of the other senses it may be stated that touch is common in

AVES 273

all parts of the body; that taste is poorly developed; that smell is
apparently not very acute, except in vultures or turkey buzzards
and other carrion-eating birds.

Fig. 223.—Brain of the hen (A, from above; B, from below): a, Ol-
factory bulbs; 6, cerebral hemispheres; c, optic lobes; d, cerebellum; d’, its
lateral parts; e, medulla. (After Carus, from Gegenbaur.)

Behavior and Intelligence.—As has been said of other ani-
mals, it is exceedingly difficult to judge what goes on in the mind
of a bird without ever having been a bird. It is very probable
that many writers upon animal intelligence give birds credit for

0.

Fig. 224.—Eye of a nocturnal bird of prey: Co, Cornea; Z, lens; Re,
retina; P, pecten; V.o., optic nerve; Nc, ossifications of the sclerotic; CM,
ciliary muscle. (After Wiedersheim.)

a higher intelligence than they possess because they draw mis-

taken conclusions from bird activities, or, more often, because

observations have been inaccurate or incomplete. When a
1s

274 BRANCH CHORDATA

child performs a certain action, we ascribe to him certain sensa-
tions, emotions, or phases of intelligence. When a bird does
the same thing, it is only fair to believe that these same activities
are accompanied by similar, though perhaps less distinguishable,
psychologic processes. If we deal fairly, and our observations
are complete, much may be learned to add to the meager informa-
tion given in our scientific books upon this fascinating subject.
Always ask these questions: Exactly what did the bird do?
Under precisely what circumstances? Possible causes? Most
probable cause? Does the result of the bird’s action prove that
your conclusion is correct?

Scientists differ widely in their opinions on bird mind, but it
is thought that there is abundant proof that, in intelligence,
birds stand next to mammals, if they do not surpass some of them.
All will surely agree that birds feel pleasure and pain; that they
exhibit surprise, fear, sexual feeling, sexual selection, parental
affection, curiosity, industry, pugnacity, anger, jealousy, play,
grief, and a wonderful homing instinct.1 Many examples are
recorded which seem to show sympathy, revenge, recognition of
persons, and affection for, or, at least, attachment to, their human
friends. Birds recognize their offspring, they have memory, as-
sociation of ideas, and communication of ideas. Examples are
given by some of recognition of pictures. It is hoped that this
will be further experimented with. Bower birds (Fig. 225) and
others show an appreciation of beautiful surroundings, while
many birds seem to appreciate the brilliant colors and songs of
their mates. By experimenting with different colored foods
it has been proved that birds can distinguish colors in objects
and that they learn by experience and make intelligent choice.
The best possible treatise on the psychology of birds is the living,
acting bird which every student can have almost every day in
the year. Study the birds. Make accurate observations and
record them. Weigh your conclusions.

The Migration of Birds.—There is no theory which satisfac-
torily accounts for the periodic coming and going of the birds.
One theory attributes it to the varying temperature. Another
theory attributes it to a lack of food, but many of our birds come
in March, when food is still scarce and the temperature low, and

1Romanes, ‘ Animal Intelligence.” Also Darwin, “ Origin of Species,”

AVES 275

leave in August or September, when there is still an abundance of
food. Another theory is that of securing better and more pro-
tected breeding grounds. Nest concealing is possibly a factor.
Chapman believes that the origin of this great pilgrimage ‘is
found in the existence of an annual nesting season,” and that it is
exactly paralleled by the annual migration of certain fishes to their
spawning grounds, and the regular return of seals to their breed-
ing-rookeries. But what seems to us most strange is that the

Fig. 225.—Bower bird (Chlamydera maculata) with bower. (From Brehm.)

same species of birds takes the same definite route of migration
for generations, except that its range is gradually lessened or
extended. Chapman gives as an illustration of the stability of
routes of migration the bobolinks, which are Eastern birds, now
spread westward to Utah, yet, instead of migrating directly south
through Texas and Mexico, they, “true to their inherited habit,
retrace their steps and leave the United States by the round-
a-bout way of Florida, crossing thence to Cuba, Jamaica, and
Yucatan, and wintering south of the Amazon.’! The extent

1 Chapman’s “ Bird Life,” p. 60.

276 BRANCH CHORDATA

of these migrations varies. Some birds do not migrate, but
stay all winter in the same locality, often changing from an
insectivorous to a seed-eating life. Others migrate but short
distances. The snipes and plovers make extended migrations,
going from the arctic regions to the tropics, some species travel-
ling from Alaska to Patagonia.

Parasitism.—The American cow-bird and European cuckoo
lay their eggs in the nests of other birds, where the young are
cared for by the foster parents, often at the loss of their own off-
spring.

Rivalry among birds may be by means of ornament, color,
antics, battle, or song. The male is usually more brightly col-
ored than the female and puts on his most brilliant attire at the
courting season. Rarely the female is more brilliantly colored
than the male (see p. 291). In this case she does the courting,
but as a rule the female is much more inconspicuously colored,
since she is generally the one which sits upon the nest, and it is
to the interest of the family that she be protectively colored.
Darwin hclieves! in the choice of the female in mating, and that
the attractiveness of the male may lie in the tinted or lengthened
beak, or the striped or brightly colored feet, or the bright wattles
or other appendages about the head; but the most common and
the most brilhant display of colors is in the plumage. Some
think that the health and vigor generally may be the cause of
this brilhaney, but Darwin believes that it has been intensified
from generation to generation by the choice of the females, thus
perpetuating these characteristic pleasing colors and color-pat-
terns in the offspring. Mr." Wallace, strangely enough, denies
the female any part in the matter of mating, while he “ascribes
to natural selection any secondary sexual character which is of
practical use to the male in conflict with a rival.” Some birds
seem to be more easily pleased by antics and pranks which are
sometimes connected with the display of ornament and some-
times not, as if he who made the biggest clown of himself was the
favored suitor. A familiar example of the display of beauty-
spots is afforded by the flicker which sits upon a twig facing his

1 Sec Darwin's “Selection in Relation to Sex,'’ “ Descent of Man.”
2 Wallace's “ Darwinism.”
3 Baskett, “ Story of the Birds.”

AVES 277

sweetheart, “lifts his wings, spreads his tail, and begins to nod
right and left as he exhibits his moustache to his charmer and
sets his jet locket first on one side of the twig and then on the
other, and she plays back at him in a similar peek-a-boo fashion.”
The drumming of the grouse and the bill tattoo of the woodpecker
are efforts to charm. Odor has no part to play in the art of
pleasing among birds, for the musk duck is said to be the only
bird which secretes an especially odorous substance.

Battle among birds may be for self-defense or for defense of
young, but it is most commonly for rivalry, as both Wallace and
Darwin believe. For bird battles there are various kinds of
weapons. The cassowary has the elongated inner toe armed
with a long straight claw and the short wing quills modified into
spines. During the nesting season many males have wing spurs
which subside into something like knobs when the season for their
use is over. Unlike the bony wing-spur, the leg-spur is devel-
oped from the skin. Somebirds fight fiercely, while others merely

“run a bluff by some terrifying attitude, wherein they display
their wing-spurs.

Song.—There is much reason to think that the song of the
male bird is a means of pleasing or courting the favor of his
wished-for mate, though he afterward sings to cheer her during
the period of incubation. The song often ceases when the
young are hatched; there is something else to be done then.
But the song is heard again during the preparation for the
second brood.

There are many call-notes for other purposes than rivalry.
Chapman says that ‘‘call-notes form the language of every day
life, while song is the outburst of special emotion.” The call
of the mother to her young in warning, in fear, in reassurance
when danger is over, the cry of hunger or distress in the young,
the thankful little chirp when feeding or when cuddling under the
mother’s wing, the scolding of both parent birds when an enemy
approaches the nest; all these and others have their significance
in bird language. One would find this study far more interesting
than that of a dead language and the opportunity for its
pursuance is present everywhere. Try to imitate the vari-
ous call-notes of the birds with which you are familiar and make
a list.

278 BRANCH CHORDATA

Classification.—The classification of birds seems to be chaotic,
no two zodlogists agreeing. Some claim birds are of too recent
origin geologically to have differentiated as yet into well-
marked orders. They might be grouped as land birds and water
birds, or as runners and flyers, but such classification would not
be scientific. If there were a geologic scries showing the nat-
ural affinities, a natural classification would be a comparatively
easy task, as all classification should be based on development
and structure.

Division A. Rati't#

Living birds are divided into two groups, the Rati'te and the
Carina’te. Ratitz are birds with a raft-like or keelless breast
bone, wings rudimentary or too small for flight, legs large,
strong, and fitted for rapid running. As examples may be

Fig. 226.—A p’teryx austral’is, a nocturnal flightless bird with nostrils near
the end of the bill. The external wing is shown in the upper part of the cut.
(Romanes.)

named the ostrich, emu, rhea, cassowary, kiwi (Fig. 226), and
the extinct moa and other ostrich-like birds. None of these
birds is native to the United States, but in reeent years they
have been imported into some parts of the west, as Pasadena,
California, Salt River Valley, Arizona, and some other dry, warm

RATITA 279

localities, where they are breeding and becoming of much value
for their plumes.

The ostrich is the largest of living birds (Fig. 227). It may
attain to a height of 6 or 8 feet, and may easily reach, with
outstretched neck, a height of 10 feet. It weighs from 375 to
450 pounds. It is a rapid runner, a single stride is said to

see Peas 3

Fig. 227.—Ostrich twenty-six months old. (Year-book U. 8. Dept. Agri-
cul., 1905.)

cover 25 feet or more! It uses its two-toed feet in defense and

its kick is dangerous. “The cry is said to be hoarse and mourn-

ful, resembling the roar of a lion or the lowing of an ox.”’ The

eggs are 5 or 6 inches in length, and one ostrich egg equals a

score of common hen eggs. They are laid in a hollow nest in
: 1Evans, “ Birds,” p. 28.

280 BRANCH CHORDATA

the soil or sand and one nest may contain as many as twenty-
five or thirty eggs, several hens laying in one nest. The male
does most, of the incubating, the eggs hatching in from forty to
forty-five days. The ostrich is a native of Africa. It is found
from Barbary to Arabia and even into Mesopotamia, where it
has long been domesticated. ‘The plumes are plucked or,
preferably, cut twice a year.” The flesh is coarse and little

. Si Rey ok age,

Fig. 228.—Ostriches five days old. (Year-book U.S. Dept. Agricul., 1905.)

used. The yearly sales in South Africa amount to nearly five
million dollars.

The three-toed rhea, or so-called ostrich, is a South American
bird. Rheas are shorter than the ostrich and the feathers are
rounded and very soft. Their favorite haunts are the ‘treeless
flats of the Argentine Pampas, the scrub-covered plains of Pata-
gonia, or the dry open sertoes of Brazil.’”!

The cassowaries and emus have rudimentary wings, and they
lack the ornamental wing and tail plumes. The hair-like coat
is characteristic. The female cassowary is larger than the male,
and both sexes are black. The plumage is made into rugs, mats,
and head ornaments.

1 Evans, ‘‘ Birds.’

WATER BIRDS 281

Division B. CariInaTa

This group contains the birds with a keeled breast-bone. It
is usually divided into seventeen orders by American ornitholo-
gists. The orders of birds are not well differentiated as compared
with the reptilian orders. The classification followed for Car-
inate is that of Reed and Chapman in their ‘‘Color Key to North
American Birds.”

WATER BIRDS

OrderI. Pygop’odes.—Auks, grebes, and loons are examples of
this order of marine birds. Their legs are situated far back on
the body, the feet are broadly webbed, and the bills are narrow.
They are good swimmers and divers, and some are good flyers.

Fig. 229.—Great penguin (Aptenody’tes patagon’ica.) (After Tenney.)

The penguins, of which there are about twenty-eight species, are found
in the Antarctic region and on the South American coast (Fig. 229).
When on land these birds rest on the whole metatarsus and assume an erect
attitude, their legs being situated very far back. They are famous swim-
mers and divers, but they cannot fly. Their wings are degenerate, being
really feathered flippers. These feathers in some species look more like

282 BRANCH CHORDATA

scales.1. When under water the wings act as paddles and the feet as rud-
ders. Penguins are gregarious, swimming in schools, and are seldom
seen on land except at the breeding season, when they go in great numbers
to their rookeries. The nests of grass and leaves may be under stones or
in caves or burrows. The male assists in incubating the two white or
greenish eggs, which require six weeks to hatch. The young are blind and
altricial, and are fed by the parents, which insert thcir bills in those of the
young. The food of the penguin consists of crustaceans, mollusks, and
fishes with a small amount of vegetable matter. The voice may be a
hoarse bark, ‘‘ croak or scream, or a murmuring sound, or, in the young, it
may be a whistle.”

Order II. Longipen’nes.—These are mostly sea birds, with long
wings and webbed feet. Gulls and terns may be named as ex-

an a siete ate wee S “ees ce

= Fees B

Fig. 230.—Franklin gull; 15 inches. (Photographed from specimen.)

amples of this order (Fig. 230). Gulls feed chiefly on fish, but
one may observe hundreds of them about an ocean liner as it
comes into port. They seek what is thrown overboard. They

1 Hornaday.

WATER BIRDS 283

are the scavengers of the water, feeding from the surface. Gulls
are at home in the open seas.

Terns are littoral (Fig. 231). They are more slender and active than the
gulls, and have long forked tails and pointed bills. They nest. in colonies,
coming from the South in May and remaining until September. When
in search of food the terns fly with the bill downward, while gulls carry the
bill in a line with the body. Terns nest in colonies on islands. The nest

She past
PT yt xf
a
: —
Pan) ys.
~. x
mA
4 x
A a8
= : aS,
pate »
: a
. A rn ?

2” gh

Fig. 231.—Terns in Southwest Waxher Key i in Breton Island Reservation.
(Year-book U. 8. Dept. Agricul., 1905. Photo by Frank M. Miller.)

is made of a few wisps of grass. The eggs, two or three in number, are
laid in a depression in the sand or pebbles. The young of both gulls and
terns are precocial. When frightened, both gulls and terns squat low
near the ground and remain motionless until actually touched.

Order III. Tubina’res are so called because the nostrils are
carried well forward through the two round tubes that lie either
along the top or the sides of the bill. The opening of the nostril

284 BRANCH CHORDATA

is about half-way between the base and the tip of the bill. The
bill is hooked like that of a bird of prey. ‘‘All are deep-water
birds, strong of wing, and brave spirited beyond all other birds.
The range of the order is worldwide. The most of them are
found in the southern oceans.”

To this order belong the petrels, ““ Mother Carey’s chickens,”’ which one
sees hundreds of miles out on the ocean. The stormy petrels are the smal-
lest. of web-footed birds, being no larger than catbirds. Their note is shrill,
and their flight butterfly-like.

The wandering albatross, with an expanse of wing from 10 to 14 fect,
is also 1 member of this order. It is a wonderful flyer, sailing for hours with-
out resting, always with rigid, motionless wings, rising, descending, or turn-
ing without a visible movement of them. It has been made immortal by
Coleridge’s ‘‘ Rime of the Ancient Mariner.”

Fig. 232.—A little corner of Pelican Island. (Year-book U. 8. Dept.
Agricul., 1905.)

Order IV. Steganop’odes.—The members of this order have
the four toes connected by a web. The bill has no lamellae.
The nostrils are small or wanting and the throat is usually
pouched. Here belong such large aquatic birds as the frigate
or man-of-war bird, the cormorant, and the pelican.

WATER BIRDS 285

The frigate or man-of-war bird is a very long-winged, long-tailed bird
of the ocean. Its legs are very weak, but it is a remarkable flyer. It is
found hundreds of miles from shore on the ocean. These birds live in the
southern waters of both hemispheres. In the Cocos-Keeling Islands,
Mr. H. O. Forbes says, they gain their living by forcing other fishing birds,
like the gannets and noddy terns, to disgorge the fishes they have caught.

The cormorants are large, green-eyed, marine blackbirds. They are
common along the seashore. They feed chiefly on fish and are gregarious.
Their gular pouch is rudimentary as compared with that of the pelican.
The Chinese tame the cormorant and use it in catching fish. The pelican
is used for a like purpose in the East Indies.

The pelicans are large birds, with very large bills and immense gular
pouches in which they catch the fish upon which they feed. The brown
pelican (Peleca’nus fus’cus) of Florida is a sociable bird, about 4 feet in
height. It docs not acquire its full colors until its third year. The neck
of the adult bird is in two colors, white and a rich blackish brown. The
back is a beautiful silvery gray-brown effect composed of many tints.
The top of the head is white or yellowish, the pouch a bluish purple or
greenish. The bill is a foot long and demands and supplies four pounds of
fish each day. Pelican Island, Florida, is the government reservation for
these birds (Fig. 232).

The California brown pelican (Peleca’nus califor’nicus) is found along the
Pacific coast from Galapagos to British Columbia. The beautiful great
white pelican (P. erythrorhyn'chos) is now rare. It is found in large western
inland lakes and in the Yellowstone National Park. The male has a pe-
culiar knob on the bill during the breeding season only.

Order V. An’seres.—These birds have flat, lamellated bills
(Fig. 233). The body is rather flat. The legs are far back on
the body, causing them to waddle when they walk and making
them good swimmers. Their toes are webbed. The feathers
are well oiled so they can go into the water. Geese spend less
time in the water than ducks do. The food is largely vegetable.
The swans, geese, and eider duck do not dive in feeding, but
thrust the head and neck under water, sometimes tipping up the
body. Marine ducks are expert divers. The wild geese, ducks,
and brant are migratory, but they are not so numerous as
formerly, since so many have been slaughtered for market and
sport

The swan belongs to this order and is the largest of the Anseres. In
fact, it is one of our largest birds. Hornaday says it is pugnacious and
quarrelsome. The plumage of the trumpeter swan is white; the bill and
feet areblack. The youngareadirty gray. The “ voice is like a blast from
a French horn,” but is musical when given by a large flock in chorus. The
range is from the Gulf to the fur countries. They breed from Iowa north
and west to the Pacific coast.

286 BRANCH CHORDATA

Order VI. Odontoglos’se.—The American flamingo, of the
warm parts of the Atlantic coast, is our representative of this
order. It is a large, web-footed, long-necked, wading bird.
The color varies from rose to vermilion. It has a heavy, bent,
lamellated bill, with which it scoops up and crushes small mol-
lusks and crustaceans, on which it feeds. Its webbed feet are
used more for support in walking on the soft mud than for swim-

= = S — aes

Fig. 233.—Ring-necked duck (Aythya collaris); 17 inches. (From speci-
men.

ming. Flamingoes nest in colonies. A colony visited by Mr.
Chapman contained upward of two thousand nests. One or
two eggs make up a clutch. The voice is a vibrant honking,
like that of a wild goose.

Order VII. Hero’diones.—This order is represented by such
birds as the storks, herons, ibises, and spoon-bills. They are
long-billed, long-necked, long-legged, wading birds, with short
tails and broad, rounded wings. They frequent the water and

WATER BIRDS 287

seize their prey, be it fish or frog, with their long sharp bills.
The young are altricial.

There are probably twenty species of sforks, all but two of which are
found in the Old World. The migratory stork of Europe is the most famous.
Their clumsy nests are known over the world.

Fig. 234.—American egret (Ard’ea egret’ta). Length, 41 inches. (Photo-
graph from specimen with neck extended.)

The herons are variously called the bittern, the great blue heron, the
green heron, the great white egret, and the “ squawk.” Many have
ornamental crests and plumes. Some herons stand in waiting, while
others run rapidly and noisily through the water, depending on their
agility in capturing their prey. Some stalk slowly and silently along in
shallow water, the head carried in front in a line with the shoulders, and
the large eyes scrutinizing every object in the water. Herons and ibises
are gregarious, nesting and roosting in flocks, but feeding individually.

288 BRANCH CHORDATA

The heronry or rookery is located in low trees on a small island or marsh.
Bitterns are found singly or in pairs. :

The herons, egrets,! und ibises have been so persistently hunted for their
plumes that some species are now quite rare. The snowy heron (Ard’ca
candidis’sima) and the American egret CArd’ca egret'la) (Fig. 254) are
the most beautiful of these. Their black legs and bills only intensify the

ST

al VR

Pig. 235.—Sand-hill crane (Grus merica’na). Length, 44 inches. (From
specimen.)

snowy whiteness of their plumage. ‘The filmy aigrettes are like spun glass.
These number about fifty and are worn by the mother during the breeding
season only. To obtain these plumes the mother must be shot, and the
nestlings are left to perish simply to gratify the vanity of thoughtless
women. The sale of these aigrettes in the United States is now forbidden
by law.

1 Apgar’s “ Birds of the United States,”

WATER BIRDS 289

Order VIII. Paludic’ole, as the name indicates, are marsh-
inhabiting birds. The crane is a familiar example.

The coot, or mud-hen, is abundant in reedy swamps, near
small creeks and shallow lakes. It is an excellent swimmer. Its
foot is scalloped or only half-webbed. It is omnivorous.

The rails and cranes resemble large or overgrown Limicole. The young
are precocial. These birds usually feed on surface materials rather than

Fig. 236.—A valuable bird in danger of extinction—field plover. (Year-
book, U. 8. Dept. of Agricul., 1907.)

by probing in the mud, as the plovers and snipes do. The rails are chiefly
marsh or swamp birds of medium or small size. The Virginia rail is a little
smaller than a quail. ‘‘ He is an odd-looking bird, with a half-quizzical,
half-cynical expression. His eyes are blood red and deeply sunk in the
long, narrow head.”

The cranes (Fig. 235), of which there are but three species in North
America, are easily distinguished by the long bill, long head, very long neck,
short, broad wings, short tail, and very long legs. They fly in single file
with legs and neck outstretched. The cranes resemble the rails in general
structure, but the herons in external form,

19

290 BRANCH CHORDATA

The whooping or white crane is now very rare. A full-grown one is
4} feet high. Hornaday says its trumpet call will carry as far as the roar of
a lion. The sand-hill or brown crane ranges from the Gulf to Manitoba.
The nests, of roots, rushes, and weeds, are made on the ground and usually
contain two eggs. Goss says “ during courtship and the early breeding sea-
son their actions and antics at times are ludicrous in the extreme, bowing
and leaping high in the air, hopping, skipping, and circling about with
drooping wings and croaking whoop, an almost indescribable dance and

Fig. 237.—Long-billed curlew (Nume’nius longirés’tris); 23 inches. (Photo-
graph from specimen.)

din, in which the females (an exception to the rule) join, all working them-
selves up into a fever of excitement only equalled by an Indian war dance,
and, like the same, it only stops when the last one is exhausted.”

Order IX. Limic’ola.—These are small or medium-sized birds,
usually brown or gray, with some white in their plumage. The
bill is long and slender and the legs spindling. Except in a

LAND BIRDS 291

few species the tibia is bare of feathers, sometimes almost to the
knee. With a single exception, the hind toe is short and elevated
or lacking. There are about 125 species of these shore birds, or,
as their original name suggests, mud-dwellers, of which 75 live
in America, north of Mexico.

The Phal’aropes are small in size and in number of species, of which there
are but three. These lobe-toed birds have this peculiar characteristic:
the female, which is larger and more brightly colored than the male, does
the courting. The male does the incubating and cares for the young,
which are soon able to swim and to hunt their own food.

Snipes and plovers (Fig. 236) are much sought for game birds in some
regions. The young are precocial. They afford some fine examples of
protective resemblance. One may be very near a snipe and not see it if
it only keeps still, so perfect is its resemblance to its surroundings.

The Jack snipe (Gallina’go delica’ta) and the American woodcock
(Philohe'la minor) have shorter legs and the eyes are farther back on the
heads than in any other birds. Their long, straight bills have sensitive
tips, with which they probe down into the mud for earthworms. Horna-
day describes the shrill ery of the Jack snipe when it rises as a half-scream,
half-squawk. Its range is large, extending all through the United States,
except in arid regions.

The avocet or stilt (Recurviro’sira americana) is like a snipe, but the legs
and bill are much longer than those of a snipe.

The curlews (Fig. 237), sandpipers, and oyster-catchers also belong to
this order.

A plover (4gialz’tis vocif’era), commonly called killdeer, is found through-
out the temperate portion of North America. They are quite common
birds in the Mississippi Valley. Though scattered when feeding, they fly
in flocks.

LAND BIRDS

Order X. Galli’n2.—This order includes many birds val-
uable to man, as pheasants, pea-fowls, guineas, chickens, turkeys,
quails (Fig. 238), and prairie-chickens. The birds of this order
are chiefly ground birds, living largely on seeds and grains, hence
the crop and gizzard are welldeveloped. Their bodies are robust,
their wings rather short, the legs stout, and the feet clawed.
The bills are short and stout. They are poor flyers, often going
with a “ whirr.’”’ In the wild forms the protective resemblance
is almost perfect, their colors blending with the grass, brush, and
weeds in which they live. The ptarmigan (Fig. 239) changes
color with the season to suit its environment, being white in
winter. The males of this order usually have conspicuous mark-
ings on the head, as the rooster’s comb and wattle, and the red
head of the turkey gobblers, or conspicuous plumage, as the pea-

292 BRANCH CHORDATA

cock. They are polygamous. The rivalry is keen and the
males fight fierce battles.

The only native bird of the pheasants is the wild turkey, now almost
exterminated by the sportmen, being found in a few regions of the Eastern
and Southern States, and in Oklahoma and Texas. Several pheasants have
been introduced into this country from China, The common chickens are
descendants of the jungle fowl of India (Gallus bankinus).

The grouse family all nest on the ground. Their colors are chiefly brown
and gray, so they rely on concealment for protcetion. The “ whirr”
accompanying flight is caused by the beating of their small concave wings.

aes

Fig. 238.—Quail (Coli’nus virginia’nus); 10 inches. (Photograph from
specimen.)

To this family belong the bob-white or ‘ quail,” the sage grouse of the
West, and the onee common prairic-hen of the Mississippi Valley. The
mule prairic-chicken has peculiar salmon-colored air-sacs on the sides of his
neck which he inflates in making his ‘‘ bum-bum-boo “as he struts and bows
to his prospective mate in the courting scason.

Order XI. Colum’bea.—This order is represented in the United
States by the pigeons and doves. There are about 300 species
in the world, but only ten or cleven in the United States. The
head is small and round, the bill and legs short, the body

LAND BIRDS 293

plump, and the plumage has a peculiar iridescence. Some
live on the ground, others in trees, und still others in open places.

The turtle dove, or mourning dove, is one of our commonest species and
its plaintive cooing is quite familiar to all. It breeds throughout the
United States, and one often mects it in the country roads. It is one of the
farmer’s uscful, as well as beautiful, friends. Three stomachs, examined
ut Washington, were found to contain 23,100 weed seeds.

Darwin says our domestic pigeons originated from the blue-rock pigeon
(Colim’ba livia). The nest of the pigeon is a flimsy one of twigs, on which
it lays two white eggs, from which hatch the naked, altricial ‘“ squabs.”

AUTUMN, 7 ee

Re

TON we a _ aloe

Fig. 239.—Seasonal changes of color in ptarmigan (Lago’pus mu’tus);
4 natural size. (Romanes.)

~ at
SUMMER®

Both sexes incubate. The young are fed on “ pigeon’s milk,” the parent
thrusting its bill into the mouth of the young and discharging therein
food which has been softened in its own crop. Chapman and Reed say
also that some species of pigeons nest in isolated pairs and other species in
large colonies. If you have ever watched a pigeon drink, you know that it
holds the bill in the water till it has finished drinking. The passenger
pigeon is a noted bird for sending messages. It was formerly very abun-
dant. In 1808 Wilson estimated one flock at over 2,000,000,000 pigeons.
They are now almost extinct, another result of the hunter and his gun.

Allied to the pigeons was the extinct dodo of Madagascar. It was a
giant compared to our pigeons. Look up a picture of it! and see what a
strange looking bird it was. It could not fly.

1 Evans, “‘ Birds,” p. 329.

294 BRANCH CHORDATA

Order XII. Rapto’res.—These are usually large, strong birds,
with hooked bill and strong claws for seizing and holding their
prey, which consists of fish, birds, rats, mice, and other small
mammals. To this order belong hawks, eagles, condors, buz-
zards, vultures, and owls.

Fig. 240.—Bald eagle (Halime’lus leucoceph’alus) (drawn by R. Ridg-
way); 34 inches. (Bulletin 27, Biological Survey, U. 8. Dept. of Agri-
cul., 1906.)

The hawks and eagles (Falcon’ide) (Fig. 240) comprise about three hun-
dred and fifty species and include such birds as the kites, hawks, buzzards,
and the osprey or fish-hawk. These are almost exclusively carnivorous.
Raptores are easily distinguished by their hooked bills and sharp talons.
They feed chiefly on rats and mice. Occasionally some of the hawks will
attack chickens, but there are more friends than foes among them. Hawks
build large nests of sticks in tall trees. They lay four whitish eggs with
brown blotches,

LAND BIRDS 295

The sharp-shinned hawk is small (length, 114 inches), with a long square
tail marked by widely separated dark bands across it, the widest one
nearest the end. The principal food is song birds, so this hawk should be
destroyed wherever found. Cooper’s hawk is dark brown with grayish and
brownish spotted under parts. Its tailis round. In food habits it is much
hike the sharp-shinned hawk, and it should be destroyed.

The red-tailed hawk (Fig. 241), more often called the chicken-hawk, is
a great destroyer of injurious mammals. Poultry and other birds do not
constitute 10 per cent. of this hawk's food, and all other beneficial animals
which it eats added do not make 15 per cent. So its record is 85 per cent.
as a friend, against 15 per cent. as an enemy, of the farmer.

7 &

Fig. 241.—Red-tailed hawk (much reduced). Length, 21 inches. (Bulle-
tin 17, Biological Survey, 1902.)

Owls in America north of Mexico number eighteen species. ‘‘ They vary
in size from the tiny elf-owl of Arizona (only 6 inches long) to the great gray
owl of the Arctic regions (30 inches long). The owls (Fig. 242) (Bubon’ide
and Strig’ide) have a soft plumage, hence their silent flight. Their eyes are
large and dilatable, enabling them to see well at night. The face is so
broad that both eyes look forward. They are immovable, so that to look
in another direction the head must be turned. They have a peculiar voice,
a screech in our little screech owl and a ‘‘ who-hoo-whoo ”’ in the great
horned owl. When one is camping in the woods the sound of this bird
gives one queer creepy feelings until one knows what is making it. Owls
live chiefly on rats, mice, frogs, snakes, and rabbits. Some of the smaller

296 BRANCH CHORDATA

ones devour many grasshoppers and other insects. They regurgitate the
indigestible portions of their prey in little oblong balls or pellets, which may
be found on the ground under the trees in which they nest. Owls nest in
holes in trees or banks, and lay from three to five pure white eggs. They
feed at night when the rats and mice are about. Thus they are of more
benefit than the day-feeding hawks.

The great horned owl is the only specics which is harmful to man, and
even it pays something for its chickens with the mice and rats it kills.
“Mr.O. E. Niles, of Ohio, once found in a nest of this bird several full-grown

Fig. 242.—Barn owl (Strix pratin’cola). (Photograph from specimen.)

Norway rats, and on the ground under the tree containing the nest he found
the bodies of 113 rats.”! Now how many chickens would that number of
rats cat. in a year? Probably more than one great horned owl would eat,
and a lot of corn besides. The investigations at Washington prove, how-
ever, that, although many rats and mice are eaten, so many small birds
and domestic fowls are destroyed by it, that one is justified in shooting the
great horned owl.

Burrowing owls (sce Prairie dogs) nest in the abandoned nests of prairie
dogs, but do not live in the same nest. with them.

1 Hornaday, p. 223.

LAND BIRDS 297

Order XIII. Psit’taci—Parrots or paroquets are usually
highly colored, harsh-voiced tropical birds, with thick, stout
bills. The upper half of the bill extends down over the lower one.
The toes, which are used as hands, or with which they walk or
climb, are arranged two in front and two behind. There are
about 500 species of these birds. They live on fruits and seeds.
They are of considerable commercial importance. The parrot
is quite a common pet. The Carolina paroquet is the only
species found native in the United States. Its range formerly

Fig. 243.—Belted kingfisher (Cer’yle alcyon); 13 inches. (Photographed
from specimen.)

extended to the Great Lakes, but now it is found only ‘rarely
in Florida and along the Gulf coast to Indian Territory.”

Order XIV. Coc’cyges.—This is an Old World order of trop-
ical birds, ‘‘classified together in one miscellaneous group only
because they belong to no other order.”

Kingfishers are a large family of about two hundred species, chiefly of
tropical birds, represented in the United States by three species. The
belted kingfisher (Fig. 243) is our common species, described by Apgar as
“a noisy, short-tailed, large, straight-billed, crested, blue-backed bird, with
white lower parts and a bluish band across the breast.”

298 BRANCH CHORDATA

The trogons (fifty species) are brilliantly colored tropical birds. The
coppery tailed trogon of Texas is our representative. It is said to be the
most beautiful of North American birds.

Cuckoos (two hundred species) are tropical birds represented in the
United States by several species. The rain crow, or yellow-billed cuckoo
(I"ig. 244), is an example. It feeds on the tent caterpillar which infests
our trees. It is the Old World cuckoo which lays its eggs in the nests of
other birds, not our American bird. With the specics Anis, one nest serves
for several females and it sometimes contains thirty eggs. The joint owners
share in the care of the young.

Fig. 244.—Ycllow-billed cuckoo which feeds upon hairy tent caterpillars.
(After Brehm.)

Order XV. Pi’ci.—In our latitude this order includes wood-
peckers of various kinds and under various common names, such
as red-headed and downy woodpeckers (Fig. 245), sap-suckers,
and flickers or yellow-hammers. All are arboreal, and _ all,
except the sap-suckers, are insectivorous. Their toes are
arranged two in front and two behind, except in a few
American three-toed woodpeckers. The tail feathers are
stiff and help to brace the bird as it clings to the trunk of
a tree and pecks for food. The bill is strong and fitted for
drilling holes into trees for nests or to procure food. The
tongue is long, flexible, and spear-tipped, so as to enable the bird

LAND BIRDS 299

to reach a long distance and to spear the larve of insects,
on which it delights to feed. The birds of this order are poor
singers, but good drummers. Everyone has heard the tattoo of
the woodpecker on the trunk of an old dead tree. The four to
nine eggs are white, and the nest is placed in a hole high up in
the tree away from enemies. The young are naked and are
reared in the nest (altricial). There are 350 species distributed

Fig. 245.—The hairy woodpecker at breakfast. (Biological Survey,
U.S. Dept. of Agriculture.)

throughout the wooded districts of the world, except in Madagas-
car and Australia. The North American species are not highly
migratory, but are represented in the northern parts of their
range throughout the year, since they feed largely on the eggs and
larve of boring insects, which they can find all the year. They
are of great value. Two-thirds or more of the food of the downy
and hairy woodpeckers consists of noxious insects.

300 BRANCH CHORDATA

Order XVI. Machrochi’res.—To this order belongs a group of
remarkable flyers, such as the humming-bird, chimney-swifts,
whip-poor-wills, and night-hawks. These birds have long,
pointed wings. Most of them fly at dusk or at night and feed
chiefly on insects.

The humming-birds are tropical or semitropical birds of the New World,
there being some 400 or 500 species. The hawk or sphynx-moths which
feed at dusk may be mistaken for humming-birds. Apgar says several
species are found west of the Rocky Mountains in the United States. The
ruby throated humming-bird is the one we see about our trumpet-crcepcrs,
honeysuckle, and salvia, seeking both insects and nectar. Chapman siys
“the young are fed by regurgitation, the parent bird inserting its bill
into the mouth of its offspring and injecting food as though from a syringe.”
Its note is a mere squeak or prolonged twitter. A humming-bird’s nest. is
about the size of a lady’s watch, and the two frail, pearly white eggs, like
large peas, hatch in fourteen days.

The swifts are widely distributed. They have strong wings. They can
fly straight up or down and feed on the wing. The legs are so weak that
some species cling to a vertical surface, using the tail to help support them,
instead of perching. The tip of each tail feather ends in a sharp point,
the shaft extending beyond the vance. They nest in hollow trees or chim-
neys. ‘“ The nest of our chimney-swift is a bracket-like basket of small
twigs gathered while the bird is on the wing, and glued together and to tree
or chimney by a glutinous saliva.”

The night-hawk resembles the whip-poor-will, and is usually compared
with it, but it is a bird of the sky, and “ its note is a loud nasal peént uttered
as it flies.” It has an enormous mouth fringed above with bristles. It
eats insects which it catches on the wing. When it alights it chooses a
nearly horizontal limb on which it sits lengthwise, looking like a big knot.
It migrates to South America in winter

The whip-poor-will is well known by its peculiar cry. It feeds on
insects which it catches at night as it flies. During the day it rests quietly
on the ground in the woods.

Order XVII. Pas’seres—This vast order comprises at least
half of the birds. They have four toes, three in front and one
behind, on a level with the front toes. The legs are rather slen-
der, and so placed on the body as to give it a horizontal position
when it rests. These are our most common birds. They vary
in size from the little house wren to the erow. Thrushes, blue-
birds, kinglets, chickadees, creepers, wrens, wag-tails, warblers,
vireos, shrikes, wax-wings, swallows, tanagers, sparrows, orioles,
crows, larks, and fly-ecatchers are representatives of this order.
They include some of our finest songsters. Most of them are
plainly clad, inconspicuous birds, working and singing, often
unseen. Not all of them, however, are unattractive in ap-

LAND BIRDS 301

pearance, for think of the bobolink, the magpie, the jay, the
grosbeak, the tanager, the cardinal, the oriole, and the modest
little wax-wing. Each brings to one’s mind a different type of
beauty. The temperate zone contains the sweetest singers in all
the bird world. The great majority of this order live upon insect
food, wherein lics their greatest value. Others live on weed
seeds and waste grain, and, lastly, on fruit in its season.

The fly-catchers (Tyran’nidw) (lig. 246) are found only in America,
being especially abundant in the tropics. They number over 350 species.

Fig. 246.—Pheebe. (Bulletin 17, U.S. Biological Survey, 1902.)

Of the thirty species that breed here, not more than a half dozen are
permanent residents of the temperate region. They feed on insects, mostly
injurious ones, which they catch while on the wing

The true larks (Alau’dide) are chiefly Old World. birds, there being about
100 species in Europe, most notably the skylark. We have only about a
dozen of this family, the horned and shore larks. The “ meadow-lark ”
belongs not in this family, but with the blackbirds.

Of the crows and jays (Cor’vide) we have about twenty-five of the two
hundred species. They are migratory only to a certain extent, being
winter residents except in the North. They are omnivorous, eating fruits,
seeds, insects, and, in some eases, the eggs and young of other birds. This
last habit is by far their worst one. They have unusual intelligence.

302 BRANCH CHORDATA

The orange and black Baltimore oriole (Fig. 247), one of the most. beauti-
ful, as well as useful, of our summer birds, destroys many tent caterpillars
and other hairy larvee which few birds will eat. If one has ever known
his rich, clear whistle, one can never forget it or fail to recognize it when the
bird arrives about the first week of May. The delicate hanging nest,
which the female weaves of grass and hair and strings, is a marvelous ac-
complishment. It is suspended far out near the end of a small flexible
twig, where cats and boys cannot come. The elm is a favorite nesting tree.

Fig. 247.—Baltimore oriole attacking nest of American tent caterpillar.
(Bulletin 75, 1900, New Hampshire Coll. Exp. Station.)

Grackles or blackbirds are common summer residents. They are said
to have the same bad habit as the jays and crows, of eating the eggs and
young of other birds, though they cat also many injurious insects.

The cowbird lays its eggs in the nests of other birds. It should be killed
and its eggs destroyed.

The largest. family (Pringill’ida) of birds (about 500 species), containing
the finches, sparrows, and grosheaks, is represented everywhere except in
the Australian region. They are chiefly secd-eating (Fig. 248) and so are
less migratory than insect-cating birds. The sparrows are plain-inhabiting
and are protectively colored, while the more arboreal grosbeaks and
finches are rather brilliant.

LAND BIRDS 303

“a

i
pple

ge

Fig. 248.—Four common seed-destroying sparrows: 1, Junco; 2, white-
throated sparrow; 3, fox sparrow; 4, true sparrow. (Bulletin 17, Biological
Survey, U. 8. Dept. of Agriculture.)

304 BRANCH CHORDATA

Although the tanagers are distinctively American, only five of them come
so far north as the United States. They are remarkable for their brilliant
plumage. When one sees the tanager in his royal or ‘‘court costume” one
feels that this beautiful bird of summer has indeed put brightness into
that day. Tanagers are arboreal, loving the woods. They feed on
flowers, fruit, and insects.

Swallows (Hi’rundin'ide) have a remarkable power of flight. In
summer they are found throughout North America. Our barn swallow in
winter goes as far south as Brazil. The number of injurious and annoying
insects which they catch on the wing is almost beyond imagination.

The wax-wings (.1mpel/ide) (Vig. 249) are found in the northern parts of
both the Old and New Worlds, though there are but three species. They
feed chiefly on wild fruits and inscets, including the elm beetle. They are

Fig. 249—Cedar wax-wing. (Biological Survey, U. 8S. Dept. Agricul.)

usually found in small flocks. Their common notes are a few unmusical
calls, which our cedar wax-wing usually utters when about to fly. The
quiet beauty of these birds is beyond all description.

The warblers (Mniolil'tide) are characteristic North American birds
and number more than 100 species, of which 70 visit the United States. The
others are tropical. With us in the temperate region they are only birds
of passage, making us brief but regular visits in May as they go to their
northern breeding ground, and again in September as they return to the
southland. Most of them are woodland birds. Some are terrestrial, some
arboreal, and others are lovers of the thickets. They migrate by night.
pees constitute nearly their entire food, and they are among our best
riends.

1 Reed and Chapman.

LAND BIRDS 305

The black-masked Maryland yellow throat is one of the tiny warblers
often seen in the Mississippi Valley. He haunts the thicket. His song,
“ witchery, witchery, witchery,” is characteristic of his active, nervous
energy.

The little black and white warbler, often called the black and white
creeper, is about 5 inches long. It is a more active climber than even the
true creepers, hanging from the under surface of branches and twigs or
flitting from tree to tree. It is usually silent. Its occasional ‘ see-see-see ””
is thin and wiry.

The wrens, thrashers, and the mocking-bird (Fig. 250) (T'roglodyt'ide)
include many fine singers. They are inconspicuously colored birds, feed-
ing near the ground. Many of them like the low scrubby tangled growth
so dear to the catbird, which cheers us all the summer day, rain or shine.
This bird does valiant service as a caterpillar hunter, especially when
feeding the young.

Fig. 250.—Mocking-bird. (Biological Survey, U. 8. Dept. Agricul.)

The creepers (Certhi’ide) do good work in keeping down the pests of the
tree trunks all the year around. .

The nuthatches (Par’id@) also help in tree keeping, as do our little chick-
adees, which stay the winter through.

The thrushes (Tur’dide@) are usually fine singers. The best known are
the much-loved robin and bluebird (Fig. 251).

There are several other families of Passeres, but lack of space forbids us
to dwell longer on this fascinating subject.

Economic Importance.—Miuillions of dollars’ worth of farm
products are destroyed annually by insect pests, but if these great
hordes of marauders were not held in check by their natural
enemies, the birds, the devastation would be so great in a few
years as to cause actual famine.

20

306 BRANCH CHORDATA

Where man has not interfered, nature has a well-balanced
arrangement for the protection of his crops. The grasses and
low-growing herbs are protected from such enemies as the cut-
worm, caterpillar, and grasshopper by the chipping sparrow,
robin, and bluelird, and, farther afield, by the quail, meadow-
lark, blackbird, and field sparrow. In the edge of the woods are

photograph by Rev. P. B. Peabody.) (Bulletin 17, Biological Survey,
U.S. Dept. of Agriculture.)

the chewinks and brown thrashers; and in the deep woods, the
ruffed grouse; while along the fresh-water streams and ponds may
be seen the woodcocks, sandpipers, and snipes. In the trees
“the woodpeckers, assisted by the nuthatches and creepers,
look after insects on and beneath the bark of both the trunk and
the branches.” The chickadees, bluebirds, thrushes, warblers,

1 Weed and Dearborn, “ Birds in Their Relation to Man.”

LAND BIRDS 307

vireos, kinglets, and many more guard the leaves. The insects
of the air are preyed upon in the daytime by the diurnal birds,
such as the swallows, swifts, kingbirds, and fly-catchers. Cre-
puscular insects are caught by such birds as the whip-poor-
will, night-hawk, and small owls.

Hawks and owls destroy many rats and mice and other young
rodents, while the vultures are very useful as scavangers, since
they subsist largely on carrion. The South African secretary
bird (Fig. 252) belongs in the list of friends.

: :

Fig. 252.—Secretary bird (Gypoger’anus reptiliv'orus). A South African
snake-killer protected by law. (After Houssay.)

Certain kinds of birds are of especially great value on account
of their specific food, insect pests which are making such havoc
with particular crops or with certain trees. Thus, the swallows,
which eat almost nothing of value to man, prey upon the cotton-
boll weevil, which they catch upon the wing. Forty-seven adult
weevils have been found in the stomach of a single swallow. It
should be remembered that the swallows, which are such inde-
fatigable insect destroyers here in the breeding season, migrate

308 BRANCH CHORDATA

to the South and are of great specific value there by reason of their
raids upon the cotton-boll weevil, so they should be encouraged

Fig. 253.—Weed _ seeds
commonly eaten by birds:
a, Birdweed; b, lambs’ quar-
ter; c, purslane; d, amaranth;
e, spotted spurge; f, ragweed;
g, pigeon grass; A, dandelion.
(Biological Survey, U.
Dept. Agricul.)

and protected from the English
sparrow. Orioles do royal service
in catching weevils on the bolls.
Blackbirds, wrens, and fly-catchers
do good work.

Sparrows prey upon the green
wheat aphid of North Carolina.

During an outbreak of canker-
worm in a central Illinois apple
orchard the investigations of Prof.
8. A. Forbes showed that the food
of robins, catbirds, brown thrashers,
and bluebirds consisted of 96 per
cent. insects, of which 16 per cent.
was cankerworms, while the food of
the house wrens he examined was
50 per cent. cankerworms; 25 per
cent. of the food of the hairy and
downy woodpeckers consists of bor-
ing larve.

It is true that birds eat a certain
percentage of fruit and seeds, but
the entire amount of vegetable
matter is usually much less than
the animal matter consumed. A
large proportion of the seeds eaten
are weed seeds (Fig. 253), such as
dandelion, dock, knot-weed, purs-
lane, pigeon-grass, and rag-weed.!
The grain which birds eat is, much
of it, picked up from the waste
matter about the farm-yard.

Doctor Judd? says the great horned owl, the sharp-shinned
and Cooper hawk, and the English sparrow are injurious birds

‘Jackson and Daugherty, ‘ Agriculture through the Laboratory and

School Garden.”
2 Linville and Kelly.

LAND BIRDS 309

and should be killed. The cowbird should be added to this list,
since it lays its eggs in the nests of smaller birds. When this
hatches, it deprives their young of room and care, often pushing
them out of the nest, or taking their food and allowing them to
starve. The blackbirds and jaybirds are questionable charac-
ters, since they are so mean about robbing nests and driving
away other birds. The protection of all but the few birds named
should be emphasized, especially by all farmers and fruit growers.

The useless destruction of bird life every year is alarming.
Besides the thousands on thousands killed for food, there are
thousands of others killed by the plume-hunters to gratify the
foolish pride of thoughtless, silly women. Much as this is to be
deprecated, it slaughters but one-fifth as many birds as those
killed by men and boys for the mere sport of killing. Surely
the killing for the love of it, many times leaving the birds to
decay where they have been shot, perhaps only wounded and
left to die by a slow torture of starvation, is a cruel and sense-
less practice, yet fully one-half of all the birds killed in the United
States are killed merely for sport.t

Surely it is time to stop and think; time to teach the coming
generation the value of birds to human life; time to teach the
boys and girls to love the birds and to study their habits, so as to
learn which are friends and which foes. Girls should learn that
a dead bird upon the hat, no matter how beautiful, is a mark of
the heartlessness of the wearer. Boys should be taught to shoot
birds with a camera, not with a gun. It takes far more intelli-
gence and skill and will be found a more fascinating sport.

Laws are being made in many states for bird protection. The
United States Government is making bird reservations, such as
Pelican Island, off the coast of Florida; Breton Island, Louisiana;
Stump Lake, North Dakota, and Yellowstone Lake in the
National Park.

Geographic Distribution.—Birds as a class are the most
widely distributed of all animals. They are at home in the
frozen regions of the North or in the dense shades of the tropics,
upon the rocky steeps of the mountains, or out on the ocean far
from sight of land. Their wide range of variation in structure
and habits renders them, as a class, able to adapt themselves to

1 Hornaday, p. 172.

310 BRANCH CHORDATA

all climates, and their mode of locomotion makes them less re-
stricted by barriers.

Important Biologic Facts.—Birds have, in common with
reptiles, the quadrate bone, and but one occipital condyle.
They are wonderfully adapted to their aérial mode of life by
their feathers, by the modifications of the fore limbs into wings,
and by the air-filled cavity of the bones. Birds are warm-
blooded (homoiothermal), the heart being completely divided
into right and left halves. The fusion of the bones of the hand
and the tibiotarsus and the tarsometatarsus are peculiar to
birds. Nest building, as well as incubation, is peculiar to this
class, though, in rare instances, fishes build nests and reptiles
practice incubation.

Classification.—

Division
A. Rati’te. Ostrich, Rhea, ete.
B. Carina’te.

Order I. Pygop’odes. | Grebes, Auks, and Loons.
Order II. Longipen’nes. Gulls, Terns.

Order IIT. Tubina’res. Albatross, Petrel.

Order IV. Steganop’odes. Cormorants, Pelicans.
Order V. An/seres. Ducks, Geese, and Swans.
Order — VI. Odontoglos’sxe. Flamingoes.

Order VII. Hero’diones. Herons, Storks, Ihises.
Order VIII. Paludic’ola. Cranes, Rails.

Order IX. Limic’ole. Snipes, Plovers.

Order X. Galli’ne. Quails, Grouse, and Chickens.
Order XI. Colum/he. Doves, Pigeons.

Order XII. Rapto’res. Hawks, Owls.

Order NIIT. Psit’taci. Parrots.

Order XIV Coe’cyges. Cuckoos, Kingfishers.

Order XV. Pi’ci. Woodpeckers.

Order XVI. Macrochi’res. Swifts, Humming-birds.
Order XVII. Pas’seres All our most common. small

(Perching birds). birds.

MAMMALIA 311

CLASS VI. MAMMALIA

Mammals are homoiothermal, bilaterally symmetric, air-
breathing, usually hairy chordates. They are, as a rule,
viviparous and suckle their young. They vary in size from the
tiny little harvest mouse, probably less than 5 inches long, to
the great sulphur whale, weighing many tons. Not all of them,
however, are widely distributed, but everywhere, save in a few
of the South Sea Islands, some of the several thousand species
are found.

Covering.—No other characteristic is more rightfully called
a distinguishing characteristic than the hair of mammals.
True hair is found on no other vertebrate. It is general to find
a hairy covering among mammals. Even among the Cetacea
hairs are sometimes found upon the muzzle, and traces of hair
are sometimes found in the embryo. The skin of the whale is
underlaid by a layer of fat or blubber, while that of those un-
gulates that are sparsely covered with hair, as the rhinoceros,
is very thick. The hair may differ greatly both in length and
texture. It may be soft and kinky “wool” or very fine fur.
The coarse hairs may become long, hard bristles, like those of
the hog, or be differentiated into stiff “spines,” like those of
the porcupine, or into a scale armor, like that of the armadillo.

Sweat glands in the skin are also characteristic of mammals.

The skeleton is the most nearly perfect of any of the chordates.
The skull (Fig. 254) is composed of fewer bones more firmly
united than in the lower chordates. The lower jaw is composed
of a single bone on each side, the dentary, and is articulated
directly with the squamosal. The skull is connected with the
first vertebra, the atlas, by two occipital condyles instead of one,
as in the birds and reptiles.

The spinal column (Fig. 255) consists of a varying number of
vertebre, the first two, the atlas and axis, being somewhat modi-
fied to support the head and to permit its various movements.
The vertebre do not articulate with one another by cup and
ball (except in some ungulates), as in amphibians, reptiles, and
birds, since the intervertebral disks of fibrocartilage permit
lateral bending of the spine. The vertebre are classified, ac-
cording to their location, as cervical, dorsal, lumbar, sacral,

312 BRANCH CHORDATA

and caudal. The cervical or neck vertebre are nearly always
seven (there are six in the manatee, and six, eight, or nine in
some of the sloths). So the length of the neck depends upon the
length, not the number, of the vertebre. The dorsal vertebre
carry ribs and vary in number (from nine in Hypero’édon! to

en

Fig. 254.—Skull of a dog, side view, with the right half of the mandible
or lower jaw and hyoid arch, the lower jaw displaced downward to show
its whole form. (Reduced). an, Anterior narial aperture; 1/7, maxillo-
turbinal bone; ET, ethmoturbinal; Na, nasal; ME, ossified portion of the
mesethmoid; CF, cribriform plate of the ethmoturbinal; Fr, frontal;
Pa, parietal; IP, interparietal; SO, supra-occipital; ExO, exoccipital;
BO, basi-occipital; Per, periotic; BS, basisphenoid; Pt, pterygoid; AS,
alisphenoid; OS, orbitosphenoid; PS, presphenoid; Pl, palatine; Yo,
vomer; Mx, maxilla; PAfr, premaxilla (sh, stylohyal; eh, epihyal; ch, cera-
tohyal; bh, basihyal; th, thyrohyal) equal the right half of the hyoidean
apparatus; s, symphysis of the mandible; cp, coronoid process; cd, condyle;
a, angle; id, inferior dental canal; *, the part of the cranium to which the
condyle is articulated. (After Tenney.)

twenty-two in Hyrax). The lumbar vertebre also vary in
number, usually inversely, as the dorsal, their sum being rather
constant. The sacral vertebre are fused together. They are
absent in Ceta’cea and Sire’nia, where there are no functional
hind limbs. The caudal vertebre vary from three to fifty.

1 Beddard’s “ Mammalia,” p. 23.

> MAMMALIA 313

mages

Fig. 255.—Skull and spinal col- Fig. 256.—Pelvic girdle of Jack-rab-
umn and single vertebra of « com- bit. (From dissection.)

mon cotton-tail rabbit (Le’pus syl-

vat‘icus). (Cleaned and mounted by

students.)

All mammals have ribs. They vary in number in different
groups, or, it may be, in different species. The greater number

314 BRANCH CHORDATA

of them are attached anteriorly to the sternum, which is always
present, and posteriorly to the vertebre, but there are also a
number of floating ribs or those attached posteriorly only.

The pectoral girdle consists of two bones on each side, the
scapula (Fig. 257) and the clavicle. The clavicle is absent
in ungulates, which use their fore limbs mainly for support and
in walking, but it is well developed in “ flying,” digging, or
burrowing mammals.

Fig. 257.—Anterior limb of man, dog, hog, sheep, and horse: Sc, Shoulder-
blade; c, coracoid; a, b, bones of forearm; 5, bones of the wrist; 6, bones of
the hand; 7, bones of the fingers. (Le Conte’s ‘Geology,’ American
Book Co., Publishers.)

The pelvic girdle (Fig. 256) consists, normally, of the os in-
nominatum on each side. There are “four distinct elements in
each one: the ischium, the ilium, the pubis, and the cotyloid.”!

The limbs which raise the body from the ground and are the
principal organs of locomotion are four in number, except in
Stre’nia and Cetacea, where there are no externally visible hind
limbs. Rudiments of the pelvis are found in both of these orders,
and in some of the Cetacca rudiments of the femur and of the
tibia. The bones of both anterior and posterior limbs (Figs. 257,

' Beddard, ‘‘ Mammalia,” p. 41.

MAMMALIA 315

258) vary in size, shape, and number, depending on the en-
vironmental habits. In all but the Cetacea the ends of the digits
are protected by horny epidermal coverings, variously termed
hoofs, nails, or claws. Rudiments of these are found in the
embryos of the Cetacea, thus suggesting their terrestrial. origin.

The Digestive Organs.—One of the peculiarities of the
digestive organs in mammals is the development of the salivary
glands. The teeth are “heterodont” (Fig. 254) instead of
“homodont,’”’ as in some of the lower classes of chordates.

Fig. 258.—Posterior limb of man, monkey, dog, sheep, and horse: 1, Hip-
joint; 2, thigh bone; 3, knee-joint; 4, bones of leg; 5, ankle-joint; 6, bones
of foot; 7, bones of toes. (Le Conte’s ‘‘ Geology,” American Book Co.,
Publishers.)

Some mammals have no teeth, at least not in the adult stage.
The teeth are attached to the premaxillary, maxillary, and den-
tary bones, and to no others. These heterodont teeth may be
classed as incisors, canines, premolars, and molars. The teeth
would indicate an omnivorous feeding habit, but this is not true
for allmammals. Some are omnivorous, some carnivorous, and
many herbivorous. The teeth often give a hint as to the feed-
ing habits, as well as proving an important element in classifica-
tion.

316 BRANCH CHORDATA

The mouth is generally characterized by thick and fleshy lips,
which serve as organs of prehension to grasp the food, as does
also the tongue, the latter being also the seat of the sense of
taste.

Owing also to the varying feeding habits, the different organs
of digestion vary in size; for example, the intestine, which is
longer in mammals than in any othcr chordate, is, in the rumi-
nants, ten times the length of the animal, while in the carnivora
it is only three or four times as long. At the junction of the
small with the large intestine there is a blind tube or cecum,
which is especially developed in most of the vegetal le feeders.

The Circulatory System.—The heart is composed of four
parts: two ventricles and two auricles. The circulation is
double, closed, and complete. The left aortic arch is present
instead of the right aortic arch, as in birds. ‘There are two
features in the venous system which distinguish all mammals
(except Echidna) from the lower chordates. The hepatic portal
system is limited to a vein which conveys to the liver blood
derived from the alimentary traci; in no mammal (except in
Echidna) is there any representative of the anterior abdominal
vein of the lower vertebrates... In no mammal is there any
trace of a renal portal system. The kidneys derive their blood
from the renal arteries only.’”!

The red corpuscles of the blood of mammals differ from those
of other chordates in being much smaller, non-nucleated, cir-
cular, and hiconcave, except in the camel, in which they are
elliptic.

The Respiratory System.—No mammals have external gills,
but all breathe by means of lungs throughout life. Respiration
is aided by a diaphragm or muscular partition, which com-
pletely divides the body eavity, separating the heart and lungs
from the abdominal viscera. When this muscular diaphragm
contracts its upper surface becomes more concave, increasing
the lung cavity and allowing the lungs to expand under the pres-
sure of the air. When the muscles relax the upper surface again
becomes convex and the lung cavity is reduced, thus forcing out
the air of the lungs.

The soft palate and the epiglottis are structures peculiar to

1 Beddard, p. 8s.

MAMMALIA 317

mammals. The vocal organs are in the upper part of the trachea
instead of the lower, as in birds.

Fig. 259.—a, Brain of rabbit, from above; the roof of the right hemi-
sphere is removed so as to expose the lateral ventricle; b, the same from
below; ¢, brain of cat; on the right side the lateral and posterior part of the
hemisphere is removed, and almost as much on the left side, and the greater
part of the hemispheres of the cerebellum have been removed; d, brain of
orang (a, b, c, after Gegenbaur; d, from the régne animal): 1°/, Cerebral
hemispheres; Mh, corpus quadrigeminum; Cb, cerebellum; Jo, medulla
oblongata; Lo, olfactory lobe; //, optic nerve; 1’, trigeminal; VI, VIII,
facial and auditory nerves; H, hypophosis cerebri; Th, optic thalamus;
Sr, sinus rhomboidalis. (After Claus.)

The Nervous System.—The brain is relatively larger in
mammals than in other chordates. The cerebral hemispheres

318 BRANCH CHORDATA

are especially developed and are connected by the corpus cal-
losum, which is not present in birds. The brain (Fig. 259), with
a few exceptions, is convoluted.

The special senses are all present except in some Cetacea,
where the olfactory membrane is degenerate and the sense of
smell is lacking. The organs of sight and hearing (Fig. 260)
vary most, owing to the different environments and consequent
habits and needs of the various species. The sense of touch,
while distributed over the surface of the body, is especially

Fig. 260.—Diagram of the labyrinth of the ear in J, the fish; JJ, the bird;
and J//, a mammal: U, Utriculus; D, sacculus; US, utriculus and sac-
culus; Cr, canalis reuniens; R, recessus labyrinthi; ('C, commencement of
the cochlea, (’, L, lagena; K, cecal sac at the apex; C, cecal sac of the ves-
tibulum of the cochlear canal. (After Waldeyer, from Gegenbaur.)

sensitive at the ends of the fingers, on the lips, tongue or snout,
and, in some monkeys, upon the under surface of the tail. The
cat has long sensitive hairs (vibrisse) connected with nerve-end-
ings, which are tactile in function. The sense of taste, situated
on the base and tip of the tongue and on the soft palate, is more
highly developed than in any other class.

The sense of scent or smell is highly developed. Correlated
with the development of smell is the presence of odoriferous
glands inmany mammals. The odors may serve for recognition,

MAMMALIA 319

for warning, or for protection by mimicking the odors of a more
formidable foe; as the odor of the musk deer may suggest that of
a crocodile.

It is readily seen that the nervous system is the highest and
most complicated of any chordate’s, thus giving mammals
highest rank in the scale of intelligence.

Order I. Méndtrém’ata—The animals of this order are
primitive mammals, but that they are mammals is proved by
the fact that they are covered with hair and nourish their young
with milk. The heart has an incomplete auriculoventricular
valve. The temperature is lower and more variable than in
the higher mammals.!_ The brain has no corpus callosum. Like
birds and reptiles, they are oviparous, and the intestines open
into a cloaca. These animals are characterized by a temporary

Fig. 261.—A spiny ant-eater. (From Claus.)

“mammary pouch,”’ in which they are hatched or to which they
are transferred after hatching, and into which open the ducts of
the mammary gland.

The spiny ant-eater (Echid'na aculea’ta) (Fig. 261) is a small nocturnal
animal about the size of a duck-bill. It is covered with spines mingled
with hairs. When danger threatens it curls up like a hedge-hog. Its
legs are short and stout, and its feet are armed with strong claws for tearing
open ant-hills. Its tail is vestigial. It has a long, pointed, toothless snout
and a long, extensible tongue for licking up ants, other insects, and worms.
The salivary glands are very highly developed, and when the tongue, cover-
ered with sticky saliva, is thrust into an ant-hill, it is soon covered with the
insects. The tongue is then drawn back into the mouth and the adhering
insects swallowed. It seems that the mother places the egg in the mammary
pouch with her mouth. When the young is hatched it is nourished with
milk. When it attains sufficient growth she removes it from the pouch, re-
placing it from time to time for nourishment. She shows further intelli-
gence by digging a burrow and concealing her young in it when she goes out

1 Beddard, p. 112.

320. BRANCH CHORDATA

at night for food. An allied form, the nodiak, is eaten by the aborigines
of the Papuan region.

The duck-bill (Ornithoryn'chus) (Fig. 262) is found in southern and
eastern Australia and Tasmania. It has a small, round head, and a
broad, flattened, sensitive bill. Its eyes are small and somewhat hidden,
but well developed. Its great paddling feet are five toed and webbed, the
webs of the anterior feet being longer than the claws. It is about the size of
our common rabbit and has short legs and a flattened tail. Its body is
covered with loose skin, protected by thick, glossy hair, with an under layer
of fine waterproof fur. The duck-bill is aquatic, digging burrows 30 or 40
feet long in the banks of streams. One opening of this burrow is below the
water. It dives, enters this opening, and is safe from its enemies. It has
teeth when young, but soon sheds them, and the gums harden into horny
plates for crushing insects, worms, snails, and mussels, which it digs out of
the mud with its snout and stores away in its cheek pouches to be eaten as

Fig. 262.—Duck-bill (Ornithorhynchus paradoxus). (From Litken.)

it drifts upon the water. Sight and hearing are acute, but it has no external
ears. The male is armed with a strong horny spur on each hind foot,
which is connected with a poison gland. The duck-bill is as shy as a beaver.
Its voice is like the growl of a puppy. The young are blind and naked.

Order II. Marsupia’lia.—Marsupials are fur-covered, terres-
trial (rarely aquatic), or arboreal, or subterranean mammals,
which carry the young, born immature, naked, and blind, at-
tached to the mammary gland in an abdominal integumentary
pouch. The milk is forced down the throat of the young by
the muscular action of the mother. The young are able to
breathe at the same time by the wrapping of the soft palate
around the upper end of the trachea in such a manner that the
air may pass from the nose down the trachea while the milk
passes down the throat. The clavicle is present. The cloaca

MAMMALIA 321

is reduced. The corpus callosum, if present, is rudimenatry.
Parameles possess a true allantoic placenta. Many thousand
skins of the opossums are used yearly. The hair is used in
making hats and felt. The fur and leather of the kangaroo
are also used.

The opossum family (Didel’phide) consists of pendactylous, plantigrade
marsupials. The pouch is present or absent according to the species. The
great toe is large and separable from the others, making the foot prehensile.
The tail is long, prehensile, and usually covered by a scaly skin and a few
scattered hairs. There are two distinet gencra. The first has been divided
into several by some authors.

Fig. 263.—The female of Didel’phys dorsig’cra, one of the South American
opossums, carrying its young upon its back. (After Nicholson.)

Genus Didelphys comprises twenty-three species, most of which are
tropical, being found in Mexico, Central America, and Brazil, but never in
Australia. It is represented in the United States by the common opossum
(Didel’ phus virginia'na). Its habit of feigning death or “playing ’possum ”
when confronted by an enemy is well known. It is about the size of a
large cat. Its nose is pointed, its eyes and ears large. It is arboreal and
nocturnal. It eats anything from insects to small reptiles and birds, and
also devours muskmelons and certain mushrooms; indeed, it is almost
omnivorous. It does not hibernate. Its young are about 3 inch in length
and are carried in the pouch for about eight weeks. After this, in some
species, they are carried on the back (Fig. 263), their tails interlocking
with that of the mother.

Tasmanian marsupials (family Dasyur'ide) are distinguished from the
American opossum by fewer incisor teeth, a rudimentary first digit on the
fore and hind feet, by the absence of a cecum, and by a non-prehensile tail.

21

322 BRANCH CHORDATA

The Tasmanian wolf has a skull like a dog’s, and is like the ordinary wolf
in size, build, and habits. It is of a dusky hue and marked upon the hind
parts with blackish bands. The hallux is wanting. The “Tasmanian
devil” is black with white patches on the body. It is the size of a badger
and its voice is a yelling growl.

The Australian ant-eater is of a bright reddish color, banded posteriorly
and dorsally with white, and looks much like a large red squirrel. It feeds
upon ants, which it captures with its tongue. Its habitat is both terrestrial
and arboreal. The young are nourished as in other marsupials, but the
pouch is lacking, and they are concealed only by the long hair of the
mother.

The Australian mole has somewhat the appearance and habits of our
common mole. It is pale golden red, in harmony with the arid soil in which
it lives. The claws of the third and fourth front toes are enlarged. “It
is not only blind, but its eyes have been more completely lost by degenera-
tion than in any other known case. Its anatomy abounds in curious
adaptations to an underground existence, evidently antique.”

The Wombats.—There are three species, one Tasmanian and two Aus-
tralian. Cheek pouches and tail are rudimentary. They are heavily
built animals, like the badger or marmot, with a shuffling gait. They are
gregarious, live in burrows, and feed upon roots. They are gentle, but
stupid. Over a hundred thousand skins are sold in London yearly.

Several of the smaller species of family Phalanger’id@ are called “flying
phalangers.” They cannot fly upward, of course, but are supported by
a parachute-like membrane from fore to hind limb, as they descend with a
sort of skimming or sailing movement. The tail is usually long and pre-
hensile, and the thumb opposable and nailless.

The Kangaroos (.Macropod’ide) are herbivorous marsupials of Australia
and the surrounding islands (Fig. 264). They have three incisors on each
side of the upper jaw and one on each side of the lower. The lower pair
of incisors are sharp on the inner edge, and to some extent may be moved
toward and from each other, cutting grass like shears. The fourth toe of
the hind foot is exceedingly long and strong, and the fifth nearly as strong,
but shorter, while the third digits are syndactylous,! but so slender that
they are of no use in supporting the body. The fore limbs are short and
small and are used only for grasping. With the exception of Dendrol’agus,
which is arboreal and has less difference in the length of fore and hind limbs,
this family is terrestrial. Locomotion consists of a series of leaps, effected
by the long limbs and the long and powerful tail.2. They vary in size from
that of a rabbit to giant forms 5 or 6 feet in height. The larva? of a large
kangaroo is not over 3 inches in length. They are gregarious, the droves
numbering from 50 to 150. They are crepuscular, nocturnal, and herbiv-
orous. They are timid, shy, and harmless if unmolested, but they can rip
open a dog with their strong hind claw when necessary to defend themselves.
When wounded they take to water, and if they get hold of a dog, they under-
take to drown it.

Genus Mac’ropus includes kangaroos and wallabies, making together
twenty-three species. Macropus rufus attains the height of 5 feet, 5

1See Glossary.

2 Some authorities state that the tail is not used in rapid locomotion,
but we know from observation of the kangaroo in the Zodlogical Gardens
that it does rest upon the tail between successive leaps in slow locomotion.

3 Beddard, p. 124,

MAMMALIA 323.

inches, not including the tail. Af. gigantius is reported by Sir Joseph Banks
as good for food. It is said that a large kangaroo in rapid flight leaps 20 to
30 feet at abound. The female will weigh 120 pounds, some old males weigh
200 pounds. The smaller species of kangaroos furnish the most fur and
leather and the best venison. About 350,000 are sold in London annually.

Rock wallabies (genus Petrog’ale) have a shorter claw on the hind foot
and a more slender tail, which is thickly covered with hair and never used in
locomotion (Fig. 264). The tail is used as a balancer, as they leap from

es

Fig 264.—FPetrogale zanthopus. The rock wallaby, with young in pouch,
(After Vogt and Specht.)

rock to rock. They are found in Australia only. The nocturnal genus
(Bettongia) and others have sometimes been inaccurately called ‘rat
kangaroos.” The four species are subterranean, with prehensile tails,
with which they carry their food, grass, roots, and leaves. One species
burrows to a depth of 10 feet. It is found in Tasmania and Australia.

Order III. Edenta’ta.—The five families of this order are
arboreal, terrestrial, or subterranean, with clawed limbs. They

324 BRANCH CHORDATA

are chiefly tropical. The name, Edentata, is somewhat mislead-
ing, as teeth are not wholly lacking, except in the family Myrme-
cophag’ide and the African genus Manis, which, having no use
for teeth, have lost them. Front teeth are always lacking in this
order. None of the teeth in the adult have enamel. They are
said to be stupid and sluggish creatures, and, except in the ant-
eaters, the brain is devoid of convolutions.

Ant-eaters (Myrmecophag’idw).—This family consists of three South
American genera, all without teeth and with long protrusible, viscid tongues,
the salivary glands being highly developed. The snout is long and the body
covered with long hair, while the tail is long and bushy. The claws are
long and powerful, enabling them to tear open the ant-hills, or, in the ar-
boreal forms (Yaman’dua and Cyclotu'rus), to tear the bark from trees and
search for insects or to defend themselves.

The great ant-eater (Myrimecophagida jubata) is said not to ‘‘fear the
presence of the serpent’s fold or the teeth of the jaguar,” and will rip
open a big dog with its claws before the dog’s tecth can make an impression
through the shaggy hair. Including the tail, this species may reach a
length of 6 or 7 feet. The tail is 2 fect long and said to be the largest of
that of any mammal. The great ant-cater sleeps through the day in a kind
of “lair” in the tall grass, where it lies ‘‘ on one side with its head buried
in the long fur of the chest, the legs folded together, and the huge tail
curled around the exposed side of the body.”! They are numerous in
their region, although the mother produces but one each year. The young
stays with the mother a year, riding on her back when little.

The sloths (Bradypod’idr), of South America, are arboreal forms, with
very long anterior limbs, short tails, and round heads. Instead of the usual
seven cervical vertebra, the three-toed sloth (Brad’ypus) or “ Ai,’ so called
from its plaintive cry, has the unusual number of nine, while the two-toed
genus (Chole’pus) has the exceptional number of six. The tocs have long,
recurved, non-retractile claws for clinging to the branches of trees. The feet
are like hooks with the fingers bent under them, hence they walk slowly
and clumsily on the ground, but climb about with case in the trees, where
they live continually day and night, hanging back downward, even in sleep,
from the lower side of the limb. They never desecnd to the ground unless
compelled to do so, but spring from tree to tree in scarch of food, which con-
sists of leaves and green shoots. They are nocturnal. Their hair is long
and shaggy and covered with minute green alge, giving the animal an al-
most perfect resemblance to a lichen-covered branch. This may be taken
as an example of commensalism betiyeen animals and plants.

Armadillos (Dasypod’ide).—There are several gencra of armadillos (Fig.
265), and they are found chicfly in South America. They are also known
in Central America, and one species is said to occur in Texas. They are the
only mammals in which the dermis develops into hard bony plates lke those
of the turtle, while the hair on the dorsal part of the body is replaced by
horny seales covering the bony plate.

“Traces of dermal armature exist in one or {wo genera of the whales.’”?

‘Ingersoll, p. 471.
° Beddard, p, 173.

MAMMALIA 325

The different forms are distinguished chiefly by the number of the movable
bands of “scutes”? between the anterior and posterior shields. The little
Chlamydoph’orus, of about 5 inches in length, has no movable bands at all,
the series of plates being uniform and continuous even to the neck. The con-
spicuous external ears so prevalent among the armadillos are also absent.
Tolypeu’tes can roll itself up into a ball and be protected by its armor, or
roll away from its enemies. Its walking is digitigrade and it is called
“ pig-footed.”’ Armadillos are omnivorous, and one species (Das'ypus
sexcinc’tus) is especially fond of carrion, burrowing up to a carcass like bee-
tles. The limbs of armadillos are short, powerful, and clawed, enabling
them to dig rapidly in the ground.

Fig. 265.—Nine-banded armadillo (Das’ypus novemcinc’tus). (Liitken.)

Order IV. Sire’nia.—These are dark-colored, sparsely haired
or bristly, toothed, herbivorous mammals. The elongated
snout of the whale is replaced by large movable lips for grasping
the food, which consists of seaweed and other aquatic plants.
External ears and hind limbs are absent. The anterior limbs
are flipper-like, but more flexible than those of the whale, and
the mother sometimes holds the young under her arm. The tail
is horizontal. Sirenia grow to a length of 9 or 10 feet. They
have two sets of heterodont teeth.

The dugong (Fig. 266) is sparsely covered with stout hairs.
The thick skin is underlaid with blubber. It is found on the
east coast of Africa, in the Indian Ocean, and the north coast of
Australia, and in the Red Sea.

The manatee is found on the Atlantic coast of South America
and of Africa, and in the mouths of the large rivers of these
countries. The blubber in the manatee differs from that of the
whale in that it has no free oil.

Steller’s sea-cow, the recently extinct Rhyti’na, was found in
herds in Behring Sea. It reached a length of 20 to 30 feet. The
flesh was good for food, and the hide and oil of value.

326 BRANCH CHORDATA

Order V. Ceta’cea.—The whales must be regarded as true
mammals, since they nourish their young with milk. They are,
however, hairless, with the exception of a small number of hairs
about the muzzle in some species. They are perfectly aquatic,
never leaving the water. Their form is fish-like, with a large
and powerful tail horizontally flattened, with a fluke on each
side. The tail is the chief organ of locomotion, moving up and
down in a sort of rotary motion, and thus propelling the animal
from place to place.!

Fig. 266.—The dugong. (From Brehm.)

The fore limbs are fin-like paddles or flippers and are used as
balancers. Whales have lost all external trace of hind limbs,
but a pair of small vestigial bones is found embedded in the
body. A fleshy dorsal fin is generally present.

Whales (Fig. 267) are distinguished by a great rounded cra-
nium, the elongation of jaws and face, and by a prow-like snout
of fat for the defense of the skull. The mouth is very large and
the throat extremely small. The nostrils are represented by a
single or double blow-hole far back on the snout, nearly on top
of the head.“ When the whale breathes the expired air rushes
out through the nostrils. The vapor in this expired breath,

1 Beddard, p. 173.

MAMMALIA 327

together with mucus from the nostrils, is condensed into drops of
water in the cold regions, but the water taken into the mouth
does not pass out through the blow-hole. The nose is directly
connected with the windpipe, so that a whale can breathe while
swimming through the water with its mouth open. The eyes
are relatively very small, and there are usually no external ears.”
(Traces of external ears in the porpoise are recorded by Professor
Howell.)! The opening of the ear is minute. The cervical
vertebre are very short and more or less fused.

The skin is smooth and shiny, like coach leather, and a thick
coating of fat immediately underlies the skin. The blubber or
fat from whales yielded much profit from its oil until the modern

weeec ce ccnencotntt

See nee ier

TE awe Me CREE
we

Fig. 267.—Skeleton of a whalebone whale, and section of the mouth,
with whalebone: b, Blow-hole; a, upper arm; fa, forearm; h, hand; p, th, l,
small remains of pelvic or hip-bone, thigh, and leg; r, roof of the palate;
w, w, plates of whalebone; f, whalebone-fringe. (Holder’s ‘ Zodélogy,”
American Book Co., Publishers.)

method of getting oil from deep oil wells, and the scarcity of
whales has almost excluded the whale industry from the oil
trade. The toothed whales feed upon fish and larger marine
animals, while the whalebone whales feed upon minute Afollusca,
jelly-fish, and Crustacea.

The toothless whales are those in which the teeth, present in
the embryo only, are replaced in the adult by baleen or whale-
bone (Fig. 267), a horny product of the epithelium of the mouth,
which consists of a large number (from 330 to 370) of horny
plates hanging down like curtains in pairs, one on each side of
the mouth, nearly meeting each other in the middle, each pair
immediately behind another. The lower edges of these horny

1 Beddard, p. 346.

328 BRANCH CHORDATA

plates are “ frayed out”’ and form a strainer, through which the
water taken into the mouth trickles out, leaving the small
animals from the water in the mouth. This baleen or whalebone
is worth several dollars a pound, andl from 800 pounds to several
tons are derived from a single whale. One whale has been re-
ported as furnishing $12,230 worth of whalebone, and oil valued
at $3490.

Whales vary from 6 to 60 or 80 fect in length, and some have
been found 100 feet long. The voice of some species has been
described as similar to the lowing of a cow, and others like the
bellowing of a bull. The young whale is called a calf.

The great Por’qual whales may measure from 60 to 85 or even 100 feet.
A species of whale, probably of genus Balenop’tcra, is described as having a
mouth so wide that ‘divers men might have stood up in it, yet the throat
so narrow as would not have admitted the least of fishes.” |The blue
whale (Balenopter’ider stbbal‘di’) is the giant of the rorquals. The Califor-
nia gray whale is said to be a cunning, courageous enemy.

The “right whales” are from 50 to 60 feet long, the head about one-
fourth the length of the entire animal, and with no dorsal fins. The
whalebone is valuable and the oil is of excellent quality and large quantity.
In toothed whales, which have no whalebone, the orifice of the blow-hole is
single.

The sperm whales (Physeter'id@) have tecth in the lower jaw only. Phy-
se’ter macroceph’alus) is from 55 to SO feet long. The head is enormous,
ending in a great blunt snout. The mouth is ventral and “it has been as-
serted that the sperm whale turns over on its back to bite.”! The single
blow-hole is not in the median line, but on one side. Inside of the great
“square head” is a cavity lving above the skull, which during life is filled
with oil or fluid fat, of which the spermaccti of commerce is the product.
This oil is also found in other whales. Ambergris, an expensive substance
used in connection with perfumery (which is at first a greasy mass and then
hardens), is a product from the intestinal canal of the sperm whale. This
whale is tropical. The females are found in herds or schools. Their food
is chiefly cuttle-fishes. The throat is snid to be large enough? to have
swallowed Jonah. It. has great strength, being able to throw itsclf entirely
out of the water.

Dolphins and porpoises have many teeth which are present in both upper
and lower jaw. The size of these animals is small to medium. The Be-
lu’ga, or “ white whale,” is a northern species. It has a distinet neck and
free vertebre. The young are blackish, growing white as they mature.
This porpoise ascends rivers in search of food, which is preferably salmon.
One (Delphin'ide elphincraptus) is fairly common in the Gulf of St. Law-
rence.3

tBeddard, p. 862.
°’ Thid., p. 365.
8 Shipley and McBride.

MAMMALLA 329

Distribution —Celacea are cosmopolitan, mostly marine. A
few ascend rivers, some being exclusively river forms of South
America and southeastern Asia.

Use to .Wan.—A good quality of ivory is obtained from nor-
whal’s tusks (the left upper incisor which sometimes reaches a
length of 8 to 10 feet). Whalebone, oil, and spermaceti have
already been mentioned.

Geologic Distribution —The cetaceans are represented in the
Eocene and Miocene of Europe, Egypt, and North America.
Both whalebone whales and toothed forms have been found in
the Phocene deposits. The toothed whales are represented in
the Miocene, Pliocene, and Pleistocene of Europe, North Amer-
ica, New Zealand, and Australia by the extinct heterodont family
Squalodon‘tide.

Order VI. Ungula’ta.—This is a large order of diverse forms.
A large proportion of these forms are extinct, and existing forms
are connected to some extent by fossil forms. Many of these
animals are very large. They are chiefly herbivorous. The
molar teeth are adapted for grinding by having broad crowns,
with tuberculated or ridged surfaces. Canines are absent or
small, or, in a few cases, tusk-like in the upper jaw. Although
the older types were plantigrade, the existing forms, excepting
such as Hyrax, are digitigrade, walking on the tips of their
toes. The one-four terminal phalanges are nearly always en-
cased in solid horny hoofs, which are, in reality, enlarged and
thickened claws. The weight of the body usually rests upon
these hoofs. The limbs have no power of grasping or climbing,
but are simply organs of locomotion. Clavicles are absent.
This is the only order of mammals in which horns appear. They
are surely a needed and effective means of defense in those forms
which are too heavy to be swift, as they cannot defend themselves
with teeth nor claws, as do the rodents and carnivores. The
order contains many domesticated animals indispensable to man
as beasts of burden or as food. It is the most beneficial to man
of any order of mammals.

The Hyrax (Hyracoi'dea)—This and the following family are often
placed in a sub-order. They are the survivors of those great animals of
the past that had their wrist-bones placed in a longitudinal series and had
toes which were nearly equal in length. The hyrax (Fig. 268) is a small

330 BRANCH CHORDATA

animal found in Ethiopia, Africa, and Arabia, including Palestine. It
is sometimes called the ‘‘rock-rabbit,” since the most species live among
rocks and mountains, and their squatty attitude, short tail, and split
mufHe, as well as a pair of rodent-like incisors in the upper jaw, remind one
of the rabbit. They have no canine teeth. Some species are found upon
the trunks and large branches of trees, and sleep in the hollows of trees.
The skull shows affinity with the Perissodactyles and also with the rodents.
The ears are short and the body fur covered. The clavicle is absent, the
radius and ulna complcte, but often ankylosed. The hyrax has a greater
number of trunk vertebra than any other mammal, twenty-one or twenty-
two of them bearing ribs. The hyrax differs from all other mammals in
having, in addition to the ordinary cecum, a pair of supplementary ceca
situated some distance down the large intestine.

The Elephant (Proboscid’ea).—The skin is greatly thickened and scantily
covered with hair. There is a tuft of hair on the end of the tail. The mass-
ive, stiff limbs are quite free from the body. The nose and upper lip? are
produced into a long, flexible, muscular, prehensile trunk or proboscis (Fig.
269), at the end of which the nares are situated. There are five complete
digits on both fore and hind limbs, and though they are bound together in

Fig. 268.— Hyrax syriacus.

the integument, each is encased in a separate hoof. The skull is very large,
but the bones are rendered light by their numerous air cavities. The brain-
case is small in comparison with the size of the skull, as the bones are
enormously thickened. In some specimens the bony skull wall is greater
in diameter than the cranial cavity, the frontal bones in older animals some-
times reaching the thickness of one foot. In existing forms there is a
single pair of upper incisors, which develop into long tusks of solid ivory.
A single tusk sold in London in 1874 weighed 188 pounds. There is no
trace of any canines. Molars are so large that there is never but a single
functional one on each side of each jaw at a time. They are transversely
ridged. Elephants are herbivorous. The stomach is simple and the cecum

1 This is supposed to be the cony of the Bible, where it is spoken of as a
“wise, though a feeble folk.” It is said to be too wise to be caught
in traps, at least, but the further reference that it ‘“‘cheweth the cud, but
divideth not the hoof” throws some doubt upon its identity. However,
Bruce kept one in captivity and found that it did chew the cud. (See
Beddard, p. 234.)

2 Beddard’s ‘‘ Mammalia.”

MAMMALIA 331

wide. The cerebral hemispheres are much convoluted, but the cerebellum
has no convolutions. There are but two living species: one (El’ephas
africanus) is found in the forests of tropical Africa, the other (#. indicus)
is found in India, Ceylon, and the Malayan Islands. The African species
has not the two rounded bosses which give the wise countenance to the
Indian species, and its head slopes back more and the ears are much larger.
It is digitigrade, though a thick pad of fat makes it appear plantigrade.
It reaches the height of about 12 feet. ‘‘ Jumbo” was 11 fect. to the shoul-
der and weighed 63 tons. There are tusks in both sexes, but in this species
they are larger in the female. The tusks are used not only as a means of
defense, but especially the right one is used also for grubbing roots for food.
The Africa’nus is more active and savage than In’dicus, but it has been
tamed. It is not used in Africa now save for food and ivory. It is
long lived, maturing at forty and living one hundred and fifty or more

Fig. 269.—Various uses of the trunk of the elephant: 1, Drinking; 2,
pulling grass; 3, washing. (From Holder’s ‘‘ Elements of Zodlogy,’’
American Book Co., Publishers.)

years. Elephas indicus is invaluable as a beast of burden on account
of its great strength, though not all are to be depended upon. One may
be perfectly docile and obedient, and another furious, vicious, and un-
manageable, but, stranger yet, they are sometimes exceedingly timid.
Baker tells of one he was riding fairly bolting at the sight of a hare. The
elephant rushes into the nearest jungles, when bolting, tearing through
the underbrush, while the rider is swept off or torn by the thorns. Its
obedience to the slightest sign of the Indian mahout shows that it has con-
siderable intelligence. Baker asserts that the locality and time of ripening
of particular kinds of fruit are remembered by it. The power of remember-
ing and recognizing individuals is proved by their revenge of particular
treatment of certain keepers. This group of ungulates appeared in the
Miocene.

The Mammoth is an extinct form which once was found about the north
pole in Siberia, Europe, and America. It was covered with long, woolly fur.

332 BRANCH CHORDATA

Fossil remains of another extinct form, the Mastodon, are constantly being
found in the gravel pits of Europe, Asia, and North America. Some species
have tusks in both Jaws and tuberculated molars like the pig.

The remainder of this order is included in the two great divis-
ions of Perissodac'tyla (odd toed) and Artiodac’tyla (even toed).

Perissodactyla.—The odd-toed group has the molars and
premolars of the same size and the middle toe predominantly
developed. ‘‘ The other toes in the three living families are
reduced to different degrees.”

The tapirs (Tapir’ide) are among the oldest mammals represented to-day,
the family being as old as that of Hquide, though the specialization of the
toes has never advanced so far. The fore feet are four toed, and the hind
feet three toed. The nose and the upper lip are lengthened into a short
proboscis.

An American species (Tapiride@ terrestris) is a solitary, dull, and gloomy,
timid and defenseless anim:l, hiding away near the streams in the marshy,
tropical woods in the daytime, and feeding at night. When alarmed or
pursued it always takes to the water for safety. The jaguar is its most
formidable enemy.

The Malayan forms haunt the most retired spots among the wooded
hills, thus escaping its enemy, the tiger.

The tapirs (genus Tap'irus) are now found only in South and Central
America, the Malay Peninsula, Java, and Sumatra. They are small or
moderate sized, ungainly creatures, covered with brownish-black hair.
The young is spotted and striped with white, as is the rule among quad-
rupeds of the forest.1. The tapir’s quick senses enable it to slip away,
which it can do with great rapidity, when disturbed. When at rest in the
daytime a Malayan form ‘exactly resembles a grayish boulder, and as it
often lives near the rocky streams of the hill jungles, it is not easily de-
tected.” Tapirs are browscrs, seizing and drawing the sueculent leaves and
shoots into the mouth with the proboscis. ‘ They are extremely fond of the
leaves of the low-growing cocoa plant, and they often in one night destroy
a cocoa field which has cost 2 poor Indian the hard labor of a year.”

South American tapirs are said to make interesting pets. They are
kept in the National Zodlogical Park at Washington. In Costa Rica the
tapir is much hunted, for its flesh is good, both fresh and salted, and its
thick hide is made into twisted whips (rawhides).

The primitive forms were distributed all over the world, “ but as the later
tertiary conditions changed from torrid to temperate outside the tropics,
they became extinct. everywhere save in the hot, moist climate under the
equator, where they have continued to the present time.” Although now
structurally very different from the horse of to-day, they probably repre-
sent something of the character of the ancestral horse.

The rhinoceros (Rhinocerol’idw) is a relic of nature's early attempts to
formulate the solid-hoofed type of quadruped. — It is recognized in fossils
toward the close of the Eocene in both Europe and North America, and the

‘Ingersoll, p. 372.

MAMMALIA 333

skeletons of those of the Miocene differ little from those of to-day. These
once numerous and widely scattered animals are represented by two
African and three East Indian specics.

They have three short toes on cach foot, each toe encased in a hoof-like
nail. The central or third toe is the largest, but the weight is sustained by
a sole pad. The East Indian forms (Fig. 270) have but one nose horn. The
small Sumatran form and the African forms have two horns. These horns
are simply outgrowths of the skin based upon a thickening of the nasal bone,
and are composed of a number of tapering whalebone-like fibers, which
sprout from papille. They are finely cemented together, growing at the
base as fast as they wear away at the tips. The usually naked skin is very
thick, deposited in folds, making it look like plates of armor. In fact, the
dried skin is used as shields by the oriental soldiers. The rhinoceros feeds
upon leaves, twigs, and grass. It occasionally fights a tiger or leopard.
It wallows in the mud. There is but a single calf at birth. The young are
easily tamed. Selous says the white rhinocerous puts her nose close to the

Fig. 270.—Indian rhinoceros (R. indicus).

ground and guides the little one (which precedes her) by keeping the point
of her horn close against the rump. In disposition he says they are slug-
gish, inoffensive animals, lying asleep in daytime, and coming to the water
to drink in the evening. The African species are bluish gray when clean.

The long-lipped species of Africa (Rhinocerot’ide bicor’nis) has an over-
hanging extensible upper lip with which it grasps and tears off the leaves
and twigs upon which it feeds exclusively. The calf follows alongside of its
mother. So sharp is the horn of a rhinocerous and so strong the head and
neck that it can ‘‘disembowel and toss over its back any smaller animal,
and it could rip open an elephant if it got at his side, though some African
explorers say that the rhinocerous usually runs from a man; but some are
vicious.”

The horns are used as knife-handles and as weapons. The horn of the
white rhinocerous (R. stmus) has been known to measure 56 inches long,
while that of R. bicornis is not known to exceed 40 inches. The Chinese

' Ingersoll, p. 382.

334 BRANCH CHORDATA

and Burmese “ pay high prices for the horns, tongues, and other efficacious
parts of the eastern rhinocerous, to be ground into medicinal powders.’’!

The horse (£q'uide) has the most complete geologic record of any living
animal. Fossil remains were found in the Eocene Epoch, on which there
were four front toes and three hind ones. Then in the Miocene were found
ancestors having three toes both before and behind, while at present this
family is distinguished by a single functional toe on each foot, the second
and fourth toes forming splint bones on either side of the toe. The tibia
also is vestigial.

In the Eocene times Europe and .Asia were joined in the arctic latitudes
by way of North America. The horse inhabited all continents except
Australia, but it disappeared entirely from America in the later geologic
ages, for which no adequate explanation has been made? At first it
was adapted to a forest life, but it has come to be more and more adapted
to living upon the high, dry plains, and it is one of the most highly special-
ized animals in its adaptation to its environment. The remains of man
and the horse are first found together in the interglacial or postglacial
period. ‘There is abundant proof that men first hunted and ate, then
drove, and finally rode the horse.”’

The horse industry stands second only to the cattle industry among
stock men. Horsehide leather is used for razor straps, gloves, and shoe
uppers. The hair is used for upholstery and the bones for fertilizing, and
the flesh for cheap meat. The mare’s milk is used by the nomadic peoples
of nies Asia. I<oumiss, often used as a beverage, is fermented mare’s
milk.

All our breeds of horses have been introduced from the Old World, as
there have been no native wild horses in Amcrica. The ass, the zebra, and
the recently extinct African quagga are also members of this family.
The ass is wild in both Asia and Africa, and the zebra in Africa. The breed-
ing of the hybrid mule is confined chiefly to the southern and some of the
western states. :

Artiodactyla—The even-toed ungulates, in which the third
and fourth digits form a symmetric pair, have the three or four
premolars smaller than the molars, and have a complicated
stomach.

The non-ruminants comprise the hippopotamus, hog, and
peccary. They are omnivorous. The canine teeth are fre-
quently developed into tusks.

The hippopot’amus ( Hippopotam’id@) is at present confined to Africa.
It formerly inhabited Europe and there were also Indian species in the lower
Pliocene. The common hippopotamus (Fig. 271) is thick skinned and al-
most hairless. The two strong incisors on each side of each jaw and the
canine teeth continue growing throughout life. The stomach is divided
into two parts. The cecum is lacking. This huge animal, 14 feet. long, has
very short limbs and tail. The feet have four-hoofed toes. The hippo-
potamus is nocturnal and aquatic, and not only walks rapidly along the

1 Ingersoll, p. 378.
* Ibid., pp. 354-360.

MAMMALIA 335

bottom of the river, but swims. It is thought that it swam from the Con-
tinent across to Madagascar, thus populating that island with the genus,
fossils of which are found in the swamps. The gap of the mouth is wide and
the large teeth are used in cutting the bark from trees, which is a prominent
feature of the food. They produce a strange carmine-colored secretion,
“sweat,” containing small crystals and corpuscles, from the skin. ‘‘Like
other aquatic animals the nostrils are on the surface of the head and can be
closed when under water,” where it can remain not over ten minutes, and,
after reaching the surface again, it spouts like a whale. It is a dangerous
animal to meet, as it cannot only capsize a boat, but even bite out large
portions of it and will attack man.

Fig. 271.—Hippopotamus and young. (Holder’s ‘ Zodlogy,”’ American
Book Co., Publishers.)

The hog (Suide) (Fig. 272) has four toes, but only two touch the ground,
except in miry places. The nostril is situated at the end of the tough,
proboscis-like snout. Hogs are generally covered with coarse hair or bristles.
The stomach is simple and the cecum present. The typical genus Sus is
found in Europe, northern Africa, Asia, and in the Malay Archipelago.
The wild boar is Sus scrofa of Europe.

The wild hog loves to wallow in the wet ground, but sees to it that
“cover ishandy.” The male is usually solitary, while the female and young
go about in groups of about a dozen. In India it makes huts of leaves,
grass, and twigs, so interwoven as to be practically rainproof, in which the
young are housed for several weeks. The domestic pig has been developed
from the wild hog by artificial selection and intercrossing. The African
wart-hog, the ugliest of land animals, and Babiru’sa are allied.

The hog industry in the United States represents hundreds of millions
of dollars. One-third of the hogs of the world are produced here. Be-
sides the pork used at home, large quantities are exported to Europe. It

336 BRANCH CHORDATA

is said that at the large packing-houses everything about the hog is used,
except the squeals. The hair is sold for mixing mortar or for making brushes.
The skin is used for making foot-balls. The bones and teeth are carbonized
and sold to sugar refiners or ground into a fertilizer. The sinews and hoofs
are used in making glue, the intestines for sausage-casings, and the blood for
making buttons, or, together with the refuse, for making fertilizer.
American Hogs.—The collared peccary is our best representative of the
wild hog. It is grayish black, with a white collar or streak about the withers.
It ranges from the Rio Grande in Texas southward to Patagonia. It
prefers moist, bushy, upland jungles, but it has been found in regions sur-
prisingly dry, hot, and bare of vegetation. Peccaries go in small droves,

=e
NT

Fig. 272.—Wild boar contrasted with a modern domesticated pig. (Ro-
manes.)

and feed at night on roots, mushrooms, farm products, and small animals.
“When pursued, they run in open ground with great fleetness, and m cover
will squat and dodge like a jack-rabbit.”’ When cornered they are cour-
ageous and pugnacious, fighting viciously, so that the boldest hunter ‘does
not hesitate to climb the best tree that happens to be available.’ Only
their courage and the use of their tusks have protected them from annihila-
tion in forests infested with jaguars, pumas, wolves, and ocelots. If the
musk gland is cut out as soon us the animal is killed the flesh ix palatable.

The ruminants, or cud-chewers, include the giraffe, deer, ox,
sheep, and antclope. Teeth and stomach are both adapted to an

MAMMALIA 337

herbivorous diet. In the upper jaw the canines are usually
degenerate. There are generally no incisors, never more than
a single pair, and in their place is a thickened calloused pad.
The canines of the lower jaw have taken the form of incisors.
The molars are selenodont, with crescent-shaped cusps; the
stomach is usually divided into four compartments (Fig. 273),
the rwmen or paunch, which receives the food when it is eaten;
from here it is regurgitated and chewed again as cud. It is
then passed into the second division of the stomach, the reticulum,
from which it passes into the third division, the omasum,; and
from there to the true stomach or abomasum. These animals

Fig. 273.—Stomach of a ruminant (sheep), showing the four compart-
ments: a, Esophagus; 6, paunch; c, honeycomb or reticulum; ¢, liber
psalterium or manyplies; e, true digestive stomach; f, beginning of the in-
testine. (After Owen.)

are usually large and many of them bear horns, which are larger
(or exclusively) on the males.

The Chev’rotain belongs to the primitive Asiatic and African family
Tragu'lide. It is the smallest ungulate living to-day. It has both deer-
like and pig-like characteristics. It is hornless and the stomach has but
three divisions.

The camels and Mamas (Camel’ide) have long limbs, with no trace of
second and fifth toes. The rumen has smooth walls, and from it are devel-
oped the water cells (ig. 274). Camels are wonderfully adapted to their
desert home by the sole pads on their feet; by their sandy color; by their
long necks, which give long range of vision and enable them to reach the
desert shrubs on each side of their path; by their cartilaginous mouth, which
enables them to eat the hard and thorny plants of the deserts on which no
other animal could subsist; by their small ears; by the valve-like folds by

22

338 BRANCH CHORDATA

which the large nostrils may be closed against the simoons of the desert;
and by their prominent eyes and heavy, overhanging eyelids. The hump
is w real and acknowledged reservoir of nutriment stored up during moist
seasons, as well as nature’s pack saddle for the commerce of the ages.!
For centuries the camel has been the means of transportation over the desert.
Papyrus records show it was well known in Egypt at least thirty-two
centuries ago. Yet in all these centuries ‘‘little of sympathetic association
has been gained between beast and master.” Owing to its viciousness and
stupidity it has been subjugated rather than domesticated. However, it
has been developed into many serviceable forms, some swift and elegant,
others strong and ugly.

There are two distinct species of camels, the Bactrian or two-humped
camel (Came'lus bactrianus) and the one-humped spccies (C. dromedarius)
(Fig. 275). The two species will interbreed it is said, and it is not probable
that cither is now found in a genuinely wild state. The camel is a thickly
built, ungainly pack horse. The dromedary is the finer-haired, light-step-

Fig. 274.—a, Water-cells in the paunch of the camel; 6, foot, showing
the pad. (From Holder’s ‘‘ Elements of Zodlogy,’’ American Book Co.,
Publishers.)

ping race horse. The former travels three miles in an hour and six hours
in a day, while the latter can run seventy miles aday. The latter is several
times the value of the former. The single calf is weaned when about a year
old, but it is not fitted for service until five years old. We are accustomed to
think of camels as associated with heated countries alone, but the Bactrian
camel can endure much cold, and carry on the overland trade between China
and Russia across the plains of Mongolia or Turkestan amid the snows of
winter and thedust of summer. Every spring the camel loses every frag-
ment of its hair and for about twenty days it is as naked as if clean shaven,
and is then sensitive to cold and rain. When the hair, which is at first fine
and beautiful, becomes long and thick it can brave the severest frost. Its
strong, elastic, lustrous hair is woven into warm cloth. The Andean vicu-
nia has finer, soft, curly wool. The Arabian depends upon the camel for
many things: “fuel, milk, hair for tents, ropes, shawls, and coarser fabrics;
and flesh, leather, and bones from the dead animal. Camel’s milk, though

\ Ingersoll, p. 337.

MAMMALIA 339

bitter from the wormwood pasturage, is the staple diet of thousands in
Africa.’’!

The genus Llama includes the llama, alpaca, huanaco, and vicunia.
They differ from the camel in their smaller size and the absence of the hump.

The llama was used in Peru as a beast of burden for centuries before the
Spanish Conquest, and is still the only trustworthy carrier in the higher
Andes. Its flesh is coarse and unpalatable, and its hair is coarser and in-
ferior to that of the alpaca. It defends itself by ‘‘spitting,” that is, forcibly
ejecting not only the saliva, but the contents of the stomach at any offender.
The discharge is injurious to man’s eyes. The llama can also kick and
bite. The alpaca is a smaller variety, bred in Peru and Chile for its thick
growth of black to gray or yellowish woolly hair.

Fig. 275.—One-humped camel (Came’lus dromeda’rius). (Linnaeus.)

The deer family (Cer’vid@) is distinguished from all other ruminants by the
presence of true bony antlers in the maie; the European reindeer and the
American caribou have antlers in both sexes. These antlers may be little
or much branched. They are never fused with the skull and are usually
shed annually. Each year the new ones re larger and provided with one
more tine. It takes the antlers from ten to sixteen wecks to grow to matur-
ity. During the greater portion of this time the males are weak and inof-
fensive. At this time the does are rearing the young (fawns). When the
new antlers are fully developed (about October) (Fig. 276) the males are
as savage as tigers.

The white-tailed Virginia deer (Odocoi'leus virginia’nus) is our most
widely distributed deer. It weighs about 250 pounds, is light brown in
summer and reddish brown in winter, with the under parts of throat and tail
pure white. It crouches and carries its head low, and saves itself by clinging

1 Zwemer.

340 BRANCH CHORDATA

to the cover of brush or timber, in which it is not easily perceived until it
starts to run, when it raises its tail and waves its ‘“‘white flag” right and left
in utter defiance of the rifle. If this white tail is not used as a recognition!
mark, it is surely unexplainable.

The American elk or wapiti (Ccr’nus canaden’sis) is the largest of the
round-horned deer, handsome and tall as a horse, with a luxuriant mane
and imposing antlers. The wild elks are nearly exterminated except
in Yellowstone Park, though formerly abounding from the Adirondacks and
southern Alleghenies to California and even Alaska. An effort is being
made to restock the Adirondacks, but reckless hunters make it almost im-
possible. The elk is both a browsing and a grazing animal. In winter
those in Yellowstone Park migrate southward to the sheltering valleys of
Jackson Hole. In summer they love to ascend the high mountains. They

Fig. 276.—" Pushing match.” (From life.)

are kept in many city parks, as they breed freely in captivity. The red
deer of Europe is a close ally. ‘

The reindeer (Ran'gifer taran’dus) of arctic Europe is unique in that both
sexes bear horns. These are used not. only for defense, but to shovel snow
in search for food. Their fur is of a lighter color in winter. In Spitzbergen
they migrate ‘in the summer to the inland region of the island, and in the
autumn back again to the seacoast to browse upon the seaweed’? Rein-
deer are annually imported into Alaska from Siberia for food and burden
bearers for the natives. The multiplication of these reindeer has proved a
source of food supply. The young develop into larger and stronger animals
than their parents. 7

Very closely allicd is the American caribou, which ranges from the east
coast of Greenland to the west coast of Alaska. Next to the musk-ox it is

' Glossary.
* Beddard, p. 299.

MAMMALIA 341

the most northerly of the ungulates. The caribou is an odd-looking animal,
with thick long legs and with hoofs so expanded and flattened as to make
good snow-shoes. Its covering is warm and consists of a ‘‘coat of fine wool-
like hair, through which grows the coarse hair of the rain coat.” It feels
like a thick felt mat. The food is moss and lichen. These animals migrate
southward in great herds, though they are not known beyond the Churchill
River. In spring they return to the most northern headlands, where they
bear their young. Upon these migrations the savages who live in these

i
k

feob eke 3

Fig. 277.—Rocky Mountain elk. (Farmer’s Bulletin No. 330, U. 8. Dept.
of Agriculture.)

arctic deserts of rock and snow depend for subsistence. Every part of the
animal is used. The flesh, stomach, and intestines are eaten, as are the
points of the antlers when soft, and the marrow of the leg bones. Soup is
made from the blood and meat mixed together. The hair forms the warmest
clothing; also tents, cords, and shoe-strings. Knives and needles are made
from the bones; fish-hooks, spears, and knife-handles from the horns; while
certain tendons serve as fine strong sewing thread for use with the bone
needles.!

1 Ingersoll, p. 323.

342 BRANCH CHORDATA

The American moose (Al’ces america'nus) is the largest member of the
family (Fig. 278), living or extinct, and the male has the heaviest and widest
spreading antlers.|. These are much flattene] and expanded. The moose
has a long, thick, and rather prehensile upper lip, and browses upon the
bark, leaves, and twigs of certain trees, and upon moss and lichens. It is
as fond of wading and swimming as a schoolboy. It is very fleet, and can
pass over large fallen tree trunks or a 5-foot fence with ease. Its cry is a
long, resonant baw]. The calf is not spotted. The male has a long, orna-
mental strip of hair-covered skin, “the bell,’’ which in the adult is sometimes
a foot long. The cow has neither antlers nor bell. The moose is easily

Fig. 278.—The Alaska moose (Alces americanus gigas). (Yearbook, U. &.
Dept. of Agriculture, 1907.)

handled and may be trained to drive in harness, but it does not live long in
captivity except in forest preserves. During the stormy winter ‘they herd
together in sheltered spots in the forest, and, through moving about in a
small area, the snow is trodden down until they form a moose-yard”’ of
several miles in extent. The animals browse upon the twigs of adjacent
cla and bushes, and with their antlers keep their enemies, the wolves, at
ay.

The so-called ‘‘musk-deer” differs from other Cerrid@ in the absence of

horns and in the presence of a gall-bladder, tusks, and the musk gland of the

1A pair of antlers from Alaska in the Field Columbian Museum has a
spread of 783 inches, and, together with the skull, weighs 93} pounds.

MAMMALIA 343

male. These glands, or “pads,” as they are commercially called, form the
basis for many manufactured perfumes, and command a high price, hence
these deer are rapidly diminishing in numbers.

Besides furnishing fine venison and the many other articles already men-
tioned, the deer family supplics “‘hartshorn,” or ammonia. It is made from

Fig. 279.—Giraffes feeding. (From Jordan and Kellogg’s “Animal Life,”
D. Appleton and Co., Publishers.)

the shavings and refuse left from antlers in the manufacture of handles for
cutlery.

The giraffes (Giraf’fide) have many deer-like characteristics, but neither
sex bears antlers. In their stead they have horny projections covered with
hairy skin. The giraffe is the tallest of all animals, the top of its head being
18 or 19 feet from the ground. Its neck, though so long, contains only the
same number of vertebre (seven) as that of man. Each vertebra is length-

344 BRANCH CHORDATA

ened, still the neck is not long enough to reach the ground, so that in
drinking or in reaching a tuft of grass the animal has to straddle out his legs
and lower his position (Fig. 279). The giraffe’s eyes are large, dark, and
liquid, and its face has a gentle expression, but it is sometimes vicious and
fights by kicking either with fore or hind feet. It has chocolate-colored
spots separated by pale tawny markings or spaces, but these vary in both
pattern and shade, proving a source of protective resemblance in the lights
and shadows of the leafy trees, while the long neck may be mistaken for a
weather-beaten tree-trunk. The under parts, shins, and feet are whitish.
The long neck is useful in reaching the twigs of the trees upon which the
giraffe browses, and also in allowing a wide range of vision, that it may look
out for lions and leopards in which the long grass abounds. In locomotion

Fig. 280.—Head of young prong-horn antclope. (After Hays.)

the giraffe moves both the fore and hind limb of cach side simultaneously,
giving it « rocking motion. Giraffes are natives of Africa, there being a
northern and w southern form.

The North American prong-horn (Anliloca’pra america’na) (Fig. 280)
scems to occupy, like the giraffe, an intermediate stage between the deer
and the true antclope on account of the structure of its horns. The horns
are branched in the male, like those of the deer, though having but two or
three prongs. The horns of the female are not branched. These horns—
that is, the external portion, corresponding to the “velvet” of the deer, but
which is here a true horn—are shed annually. The prong-horn has no
“false hoofs.” The male is “about 38 inches high and of a varying yellowish
brown above, darker on the face, dull white on chin and cheeks, in two

MAMMALIA 345

crescent patches across the throut, on the under surfaves, and in a broad
heart-shaped patch around the brown scut of a tail.’”’? This whiteness of
stern belongs in a greater or less degree to nearly all the ruminants and to
other gregarious animals. It is thought to be a recognition mark by which
the young and other members of a herd follow the leader or one another.
The prong-horns are gregarious. ‘The prong-horn is, or used to be, a crea-
ture of the plains, living on the dry bush grass, and avoiding these wolf- and
wildcat-inhabited thickets, but now frequently seeks their cover. The
young fawns (usually two) cling close upon the heels of the mother, which
defends them with lowered horns and sharp, striking feet. The fur is use-
less, but the flesh is delicious.

The cattle family (Bo’vide) contains the wild cattle, the bison or buffalo,
sheep, goats, and antelopes. They are distinguished by divided hoofs and
unbranched horns, which consist of a hollow sheath growing over a horny
core, which are never shed. As a rule they are present in both sexes.
They have no upper canine teeth. They are heribvorous, preferring grass
and herbage. Only a few examples can be mentioned here.

The antelopes, so far as we know, are the oldest of all bovine animals.
They date from the Miocene. They differ from true cattle in their more
graceful form, in that the horns, when curved, curve backward toward
the neck. Their skin is usually smooth and sleek. They are now limited
to Europe, Asia, and Africa, predominating in tropical Africa. The
sable antelope ( Hippot'ragus ni’ger), says Cumming, “‘is the rarest and most
beautiful animal in Africa. It is large and strong, looking much like the
ibex. Its back and sides are glossy black and the under parts pure white.
The horns are upward of 3 feet in length and bend strongly back with a bold
sweep, reaching nearly to the haunches.”’ The mane is erect, the hide satin-
like, and the whole attitude fearless and noble. Like all the antelopes, it
has an equine form and gait. It is readily tamed and seems able to breed
in captivity. These antelopes love to pasture on the open plain, a few to-
gether, mostly chestnut cows, says Ingersoll, and ‘“‘the horns are used with
undaunted courage even when attacked by lions.”

We cannot refrain from mentioning the small, active, beautiful gazelle.
“The skin is as sleek as satin, of a color difficult to describe, as it varies
between the lightest mauve and yellowish brown,” the belly and legs from
the knee down are white, the hoof tapers to a sharp point. ‘‘The head of
the buck is ornamented by gracefully curved, annulated horns, perfectly
black, and generally from 9 to 12 inches long on the bend. The eye is the
yell-known perfection, the full, large, soft, and jet-black eye of the gazelle.”
The Dorcas gazelles are found in twos and threes all over Egypt. They feed
upon juicy plants and shrubs, and visit the crops at night. They may stand
motionless untif the hunter is within rifle shot and then fairly skim the groud
in their flight.

Associated with the antelopes are the ugly gnus of South Africa.

Sheep and goats are very closely allied, the goats differing from the
sheep in their slight build, in the beard of the male, and in the horns, which
are arched over the back instead of spirally curved, as is the rule with sheep.

True goats (Ca’pra) are almost exclusively Palearctic. They are repre-
sented by the Spanish ibex (C. pyrenaica), the steinbock (('. zber) of the
Alps and Tyrol, and the Persian wild goat (C. egagrus). The Persian wild
goat is probably the principal species from which the tame goats are derived.
According to Mr. Blanford, the “‘bezoar stones,” the concretions of various
lime salts found in the stomach, were supposed to be of great virtue as an
antidote for poison. One stone of 4 ounces once sold in Europe for £200.

346 BRANCH CHORDATA

Geologically, goats are traced back to the Pliocene. Their distribution is
limited and varied, owing chiefly to their mountain-loving nature. Their
different environments and tendeny to vary have given rise to many and
very various breeds of the domestic goat.

The goats of central Asia, living in a climate of great extremes of tempera-
ture, furnish the fine wool of Cashmere and Thibet, which is their under coat.
The Angora goat of Asia Minor furnishes millions of pounds annually of
long silky hair. The cashmeres and mohairs of our stores are from goat
hair and wool. The leather from goat hide is always valuable, especially
that of morocco, while the skin of the kid is valued for gloves. The goat
has for many centuries been used as a domestic animal. It supplies an
abundance of good milk, rich in cheese-making casein, and requires much
less food than the cow. In southern Europe herds of goats are driven from
house to house and milked at the door of each customer, and then driven

Gi
Mt

Hi)
A \
Quai}

AWN

Fig. 281.—Rocky Mountain goat (Haploc’eros monta'nus).

back to pasture. The goat readily cleaves to the household and exhibits
more intelligence than other members of our flocks and herds.

The chamois of the European Alps and the Rocky Mountain goat (Fig.
281) are described as goat antelopes. The Rocky Mountain goat is the
nearest we have to the goat, for this is not a true goat. nor a true antelope.
It is twice as large as a goat and looks much like a miniature buffalo, only
its pelage is pure white, soft, and fine. Its hoofs, horns, and nose are black.
“Tt has high shoulders, low hind-quarters, thick legs, and neck. It carries
its head low. Its face is long.’ The small, angular hoofs consist of a
pad inside and a knife-edge outside, equally adapted to snow or bare
rock. It “inhabits the grassy belt of high mountains just above timber line,
and loves the dangerous ice-covered slopes,” being able to ascend almost
asa precipices. It is exceedingly difficult to capture and does not
ive long in captivity. ‘It is now found in only Idaho, Washington, and

MAMMALIA 347

northwest Montana. It is scattered at long intervals through British
Columbia and Alaska, as far as the head of Cook’s inlet.’””!

The sheep (Ovis) are almost entirely palsearctic and nearctic, barely
getting into the oriental region. They, like the goats, are often limited to
islands and small stretches of country, owing in part to their mountain-

Fig. 282.—The White Mountain sheep of Alaska (Ovis dalli). (Osgood,
Yearbook, 1907, U. 8. Dept. of Agriculture.)

loving habits (Fig. 282). There are six North American species. The
Rocky Mountain big-horn (Ovis montana) ranges from the far north to New
Mexico. The mountain sheep is a fine, sturdy animal, bold, keen-eyed,
active, and strong. It fears no storm and defies all enemies, save man with
his gun and domestic sheep with their diseases. It delights in the highest

1 Hornaday.

348 BRANCH CHORDATA

crags of the mountains, the boldest rim-rock of the plateau, or the most
rugged ‘bad lands,” for which it is adapted by its round firm hoofs, its
warm winter under coat, its ability to subsist on scant herbage, and its keen
senses. It is hunted by mountain lions and by man for its savory flesh.
It has a handsome head and massive horns curved into the half or three-
fourths of a circle, as are the horns of no other wild animal. It needs to be
secp in its native cloudland to be fully appreciated.

There are many breeds of the domestic sheep. The original of this per-
haps most useful and least educated of animals is not known. The variation
of external characters, such as horns, ears, and tail, and in the color, length,
texture, and quality of the fleece, is exceedingly great. The existence of
these numerous breeds is probably due to their tendency to vary and to
effect. fertile crosses, and to long-continued selection, combined with the
obstinacy with which these variations are transmitted and retained. Sheep
are used to an enormous extent both for the production of their wholesome
flesh and for their wool. Thousands of Persian lamb skins are used in the
fur trade annually, and hundreds of thousands of Astrakans, which is the
same breed taken when exceedingly young, it is said, before their natural
birth. This breed is also greatly valued for its fat, which accumulates on
the haunches in two great protuberances. In the fat-tailed sheep of Asia
the tail of pure fat sometimes weighs 30 to 50 pounds, and trails upon the
ground if not suspended upon wheels or carried upon a truck. This fat
is regarded as a great luxury. The Spanish Merino sheep has been intro-
duced into South Africa, Australia, and the United States. It is celebrated
for the fine quality of its wool.

The musk-ox (O’vibos moscha'tus) is a strange, long-haired, short-legged
creature of the frozen North. It belongs between the sheep and ox, par-
taking of the characters of each.

Oxen are distinguished from other hollow-horned ruminants by their
stouter build, and by their smooth curved (not twisted) horns, which stand
out from the sides of the head. The wild ox of Europe (Bos primigenius),
believed to be surviving in the herds of Chillingham and Chartley,! is
supposed to be the progenitor of our cattle. The original, called the auroch,
or, by the Romans, Urus, was of more gigantic size.

One of the largest of the family to-day is the European bison (Bos
bonasus). It looks much like our American bison or buffalo, but is taller.
Bisons differ from oxen in having a hump over the shoulder formed by
spinous processes for the attachment of the great muscles used in holding
up the massive head and in the great pushing matches of the bulls. The
American “buffalo” is more shaggy and robust than the European ‘wisent ”’
(Fig. 283). The latter was forest inhabiting, while our ‘‘buffaloes’”’ loved
the plains, where they congregated formerly in great herds in spring and fall,
but usually formed only scattered bands which traveled over the plains in
single file. The true buffalo of Africa and India has no hump and is almost
hairless. No animal is more dangerous than an infuriated bull buffalo, and
none more easily provoked. Pugnacity and revenge are its ruling impulses.
It has been domesticated in India, and is very useful, but not lovable.
Africa has two species, which are sometimes accompanied hy starlings.
In the East starlings and herons ‘‘perch on their backs and hunt for ticks
and other parasites’’—a strange, but mutually beneficial commensalism.

The yak (Bos grunnicns), of the mountains of Thibet, has short legs,
goat-like feet, humped shoulders, smooth, spreading horns, and carries its

1 Beddard, p, 321.

MAMMALIA 349

head low. From the chin, throat, and lower parts of the sides the hair
grows long and forms a fringe, a wonderful adaptation to the climate. This
long hair serves as a mat beneath it when it lies down upon the ice and snow,
as well as a warm cover under which it curls its legs. The tail is thick and
silky, sometimes 6 feet long. It is often beautifully mounted on antelope-
horn handles and used for fly-whisks in the East. The ery is much like the
grunt of a pig, but louder and longer.t| Tame yaks have long been used as
strong, sure-footed beasts of burden. The flesh, milk, and butter are ex-
cellent. From its hide, clothing, tent covers, and harness are made, and the
hair is twisted into ropes.

Fig. 283.—A group of buffaloes, ‘‘ American bison” (Bos americanus) in
Yellowstone National Park. (From life.)

The numerous breeds of domestic cattle form an enormous industry.
The exports of the United States alone, such as cheese, butter, hides, tallow,
and beef, amount to many million dollars annually.

Geologic Distribution of Ungulates—The camel is represented
in the Oligocene. The Miocene forms in America had horns
something like deer antlers. The Procamelus, the probable
ancestor of both camels and llamas, flourished in the Miocene.
In the Pliocene, Europe had deer, antelopes, oxen, and the first

1 Ingersoll, p. 247.

350 BRANCH CHORDATA

Old World camels, as well as giraffe-like forms. ‘“‘ That the
camel got the pads on his feet, the water-pockets in his stomach,
and the other drought and sand resisting arrangements from an
ancestor that began in the United States a million or more years
years ago” has been proved by Cope, Doctor Wirtman, and his
assistants. The oldest fossil deer types are Miocene. They
were small, hornless creatures. The first horned deer were in
the middle Miocene, when the horns were bifid. The giraffe,
or its close allies, existed in the Miocene. The bison existed in
the Miocene, as shown in fossil Bos sivalensis from India. The
Pliocene life included a variety of oxen and two North American
bisons.

Order VII. Rodentia or Gli’res.—Rodents are exceedingly
numerous and well-known mammals, covered with fur or spines.
They are generally small, varying in size from the porcupine, of
about 3 feet in length, to some of our small mice, not over 4 or 5
inches long.

The one distinguishing characteristic of rodents is their teeth.
(See Fig. 288, p.355.) These have enamel on their front surfaces
only. Thus, their incisors, which grow continuously from per-
sistant pulps, are always chisel shaped and kept sharp by the
wearing away of the posterior surfaces. There are never more
than two incisor teeth in the lower jaw, and only two in the
upper, except in Lepor’id@, where there are four. The lack of
canine teeth in all rodents leaves a space or diastema between
the incisors and the molars. The molars vary in number from
two to six on each side of each jaw. There is a hairy ingrowth
in the mouth back of the incisors, which serves to catch the
particles when the animals are gnawing. They are usually
vegetable feeders, but some are carnivorous or omnivorous.
The intestine is long and the cecum large (except in dormice) and
often complicated.

As a rule the clavicle is present. Most rodents are five toed.
The toes have claw-like nails. They are usually plantigrade or
semiplantigrade. The cerebrum is small and nearly or quite
smooth, but in some of the larger forms (the beaver excepted)
it is well convoluted. The cars and eyes are well developed.
The voice is a squeak or squeal. Their defense is by spines,
as in the porcupine; by biting, as in the rat; and by flight or

MAMMALIA 351

concealment, as in the rabbit, though the rabbit will fight vi-
ciously by biting and by striking with its hind feet if cornered, or
if the nest or “ form” containing the young is attacked.

Some hibernate in winter, others migrate in flocks. They live
almost everywhere, but are chiefly terrestrial; some are aquatic,
some subterranean, and still others arboreal. They are very

Fig. 284.—American flying squirrel (Sciurop’terus volucella). (From Pack-
ard’s “‘ Zodlogy,”” Henry Holt & Co., Publishers.)

prolific, the young being numerous, and, in some families, four to
six littersa year. Since they are hardy, often nocturnal, and not
very particular as to the character of their food or lodging, they
have become worldwide in distribution.

Squirrels (Sciu’rid@) are worldwide, excepting Australia and Madagascar.
The eyes and ears are large, the tail long and bushy, the thumbs on the fore
feet inconspicuous. There are four toes on the hind feet and the tibia and

352 BRANCH CHORDATA

fibula are distinct. They feed upon nuts and grain, as well as eggs and
young birds. They are chiefly arboreal, building their nests in tree-tops.
They lay up a store of food in hollow trees, where they pass the severe
winter weather. Four species of this genus (Sciurus) are found in the
United States and Canada. SS. vulgaris, the common squirrel of Great
Britain, is found from Ireland to Japan.

Flying squirrels (genus Sciurop’lerus) (Fig. 284) of the palearctic region
(which includes Europe, northern Asia and Japan, North America, and
India) have a furry membrane connecting the anterior and posterior limbs.
This, together with the broad tail, acts as a sort of parachute, enabling these
squirrels to take enormous downward leaps from limb to limb or tree to
tree. They cannot “fly” upward, but ascend the tree by climbing. The
Asiatic flying squirrel is 16 to 18 inches long without the tail, and, it is said,
80 yards have been covered in their longest leaps.

The little striped ground squirrel (Yamias striatus) burrows and carries
its food in its cheek pouches to its nest in the ground.

The prairie-dog (genus Cy’nomys), of the great western plains, is also sub-
terranean, digging a burrow and throwing up a mound at its entrance.
There are whole villages of these mounds, sometimes covering acres. The
prairie-dog hibernates in winter, at least comes out only occasionally. One
kept in a cage by the author comes out of his ‘‘straw burrow’ at night or
just before dawn, only at long intervals, for food. They sit up on their
hind feet and look all around like sentinels, but dart back into their burrows
again at the least approach of danger, uttering a shrill cry as a warning to
the rest of the community. They are so quick of movement that it is diffi-
cult to shoot or trap them. ‘Their ears are small. Their legs are so short
that in running they “hug the ground,” of which, in sandy regions, they are
very nearly the color. They grasp their food with their paws like true
squirrels.

The marmots of the arctic regions are closely allied to these. The Alpine
marmot (Arcto’mys marmotta) lives far up in the Alps. Its danger signal is
a shrill whistle. These marmots hibernate, ten to fifteen being packed
together in a well-lined burrow.

The North American beaver (family Castor’ide) is an aquatic rodent with
a stout body, flat, scaly tail, and webbed hind feet. It fells trees by means
of its strong incisors, damming the stream so as to raise the level of water
above the entrance to its burrow. The beaver (Castor canadensis) is fast
becoming exterminated on account of the demand for its fur.

Rats and mice (\/urid@) have naked tails which are scaly underneath.
The soles of the feet are naked and the tibia and fibula are united below.
Some of the numerous genera are found in all parts of the world. The
muskrat is the largest member of this family. Some of the species are
among the smallest quadrupeds known.

The North American muskrat (genus Fiber) is a genus of two species of
dark brown aquatic animals. They dig burrows in the banks of streams, the
entrances to which are beneath the surface of the water. The hind feet
are slightly webbed, the tail flattened and scaly, with scattered hairs.
The shortened thumb has a fully developed claw, and they grasp their food,
which consists of roots and water plants, with their paws, like the squirrels.
A Rocky Mountain species (/’/ber osoyoosensis) is said to construct a dome-
shaped house of “bulrushes’” in the water. It feeds largely upon water-
fowls and fish.

The common mouse (Mus mus’culus) and rat (Mf. decumanus) have
been introduced into America from the Old World. JZ. minutus is said to

MAMMALIA 353

be the smallest British quadruped, except the lesser shrews. It is 24 inches
long without the tail, which is the same length. The water rats, or voles,
represent another genus, also the meadow mice or “‘ficld mice’? (Microtus)
(Fig. 285). The typical field mouse is a ‘short-eared, short-tailed, thick-
set’ little creature 43 inches long, with a tail 12 inches long. It. is brown
above and white or grayish below. It is found from the Atlantic to the
Dakotas. It feeds on grass, roots, and grain. In severe winters they some-
times do much damage by eating the bark of young trees (Fig. 286).

Dormice.—The common dormouse of the Old World (Muscardi nus anel-
lanarius) has a long bushy tail and looks much like a tiny squirrel. Its
body is ‘3 inches long with a tail 2} inches long.”

AWS

Fig. 285.—Carson field or meadow mouse (Microt’us montanus). (Yearbook
U.S. Dept. of Agriculture, 1908.)

The American porcupines are chiefly arboreal. The quills, which are
but an inch or two long and are somewhat hidden among the intermingled
hairs, are loosely attached, so that when an animal comes in contact with
them they stick into it, and, being barbed, they pull out of the porcupine and
remain in the enemy. Hence porcupines are considered a nuisance by cattle-
men of the West. They are also annoying to the lumbermen of the North,
as they gnaw the wooden handles of their tools. | These animals are so well
protected by their spines that they need little intelligence to escape their
enemies, and are rather stupid. The Old World porcupines, by some
authorities placed in another family, have spines a foot in length. On the
tail are hollow quills, which make a rattling noise somewhat like that of the
rattlesnake to warn the enemy. The South American genus has a prehensile
tail. The little guinea-pigs are South American relatives,

23

354 BRANCH CHORDATA

Jumping-mice (Dipod'ide) (Fig. 287) are represented by the American
jumping mice and the Palearctic Jerboas. They have long tails and the
hind legs are greatly elongated and adapted for taking enormous leaps.

Fig. 286.-—Lombardy poplar killed by field mice. (Farmer’s Bulletin
No. 335, U.S. Dept. of Agriculture, October, 1908.)

oH

i thy gem
GMb i hl es

Fig. 287.— Jumping mouse. (After Tenney.)

The pouched gophers (Geomy'idir) have large check pouches opening ex-
ternally (Tig. 288, a, b,c). | These burrowing rodents are restricted to Cen-
tral America and the central plains of North America. They have small ears
and eyes. The claws of the anterior limbs are strong.

MAMMALIA 355

The family Leporide is represented by hares and rabbits. Formula for
the teeth: Incisors, 5; molars, = or 28 in all. One pair of upper incisors
is much smaller and immediately behind the other. This arrangement of

Fig. 288.—Faces of pocket gophers, showing pouches and incisors:
a, Geomys; b, Cratogeomys; c, Thomomys. (Yearbook U.S. Dept. of Agri-
culture, 1909.)

the incisors has given rise to the term Duplicidenta’ta. The soles are furred,
the tail short and recurved, the eyes large, andthe earslong. The hind limbs
(Fig. 289) are longer than the fore limbs (Fig. 290), and they “run” by

Fig. 289.—Posterior limb of Jack-rabbit. (Mounted by students.)

prodigious leaps. Genus Lepus contains thirty or forty species. Our
common forms in the United States are the ‘“cotton-tail’”’ (ZL. sylvaticus);
the marsh hare (L. palustris); the water rabbit (ZL. aquaticus), also a south-

356 BRANCH CHORDATA

ern form; the Jack-rabbit (L. campestris) of the West and Southwest; and
L. americanus, a northern variable species, whose fur turns white in winter.
They are not gregarious, though it is said they often play together on moon-
light nights. They are crepuscular and somewhat nocturnal.

Geologic Distribution Rodents appeared first in America in
the Wasatch stage of the Eocene. Almost all the principal
groups of existing forms appeared within the tertiary.

Use to Man.—Great numbers of rabbits are used for food in
the cities during the winter season. Their fur is used for making

Fig. 290.—sScapula and anterior limb of Jack-rabbit. (Mounted by
students.)

felt hats. ‘‘ Nine-tenths of the felt hats worn in the United
States are made from rabbit-fur.”” Where they are numerous
or food is scarce they gnaw the bark of young fruit trees. In
many localities the orchard is enclosed in rabbit-proof fence.
Beaver skins are also much used for furs.

Order VIII. Carniv’ora (“ Mammals of Prey ’’).—These flesh-
eating mammals may be small or large. They may be terres-
trial, arboreal, or aquatic. They feed upon the flesh and blood

' Parker and Haswell, p. 574.

MAMMALIA 357

of other animals, which they catch by cunning, by chasing, or
by stealthily creeping up upon them and pouncing on them,
whereupon they bite and tear them in pieces. Here we find
another striking illustration of the adaptation of structure to
habits. They must be fitted to attack and destroy other ani-
mals. Their five or four toes are armed with sharp claws, which,
in the cat, are retractile into a sheath by which they are pro-
tected when not in use. The teeth are adapted for seizing,
biting, holding or cutting, in contrast to the nibbling or grind-
ing teeth of the herbivores. The usually six incisor teeth are
small. The canines are long, strong, and conical, fitted for
tearing, and the premolar in the upper jaw and the first molar
in the lower jaw, called the “ carnassial teeth,” are developed
into thin, sharp, three-pointed fangs, shutting down past one
another like scissor-blades, while the cusps of the molars form
more or less angular and sharp ridges.

The stomach is simple, and the cecum small or wanting.
The clavicle is reduced, the radius and ulna well developed.
As to manner of walking, there are several gradations from the
plantigrade bears, which walk on the soles of their feet, to the
digitigrade cats, which walk on the tips of their toes. The
coloration is varied to conform to their habits. Some are
spotted, others striped, while many adults are quite modest in
their plain, uniform colors. The brain is large and well convo-
luted, and the sense organs well developed, giving them a high
degree of intelligence.

This provision of nature, wherein some animals feed upon
vegetable matter and others feed upon animals—for every living
thing, from the microscopic alge in the water to large animals
like the deer and horse, becomes food for some animal—is a
wise one. For thus the vegetation of the earth supports not only
the herbivorous animals feeding directly upon it, but the carniv-
orous animal has his food very largely prepared for him by the
vegetable-feeding animals. But the carnivorous animal also
aids the herbivorous survivors in their struggle for existence, for,
was not the number kept within bounds, the rapidly multiply-
ing herbivores would soon absolutely destroy the vegetation of
the world.

These animals are usually clothed in dense, soft hair, and

358 BRANCH CHORDATA

many of them are valuable for their fur. The cat and dog have
been domesticated.

The Terrestrial Carnivora (Fissipe’dia)—The number of
digits may be five on each foot, but is often reduced to four on
the hind feet, as in cats and dogs, and sometimes to four on the
front feet, as in Hye’nide, but the reduced first toe may bear a
claw.

The cat family (Fe’lidw) includes the lions, tigers, leopards or pan-
thers, jaguars, pumas, lynxes, wildeats, etc. They are widely distributed
in both the Old World and the New, but are absent in Australia.
They seem to have evolved in the Old World first, migrating to North
Amcrica at the close of the Pliocene, and from thence to South America.
The legs are relatively short and the claws are retractile. The terminal

Fig. 291.—Bones and ligaments of the toe of a cat, showing the claw re-
tracted (A) and protruded (B).

joint bearing the claw (Fig. 291) folds back into a sheath by the outside
of or above the middle joint, and is held there by astrong ligament. This
is the natural position of the claw and prevents it from friction. When
wanted for aggression or defense it is pulled into position by the flexor
muscles bearing the claw.

The raccoons (Procyon'ide), placed by some with the bear family, are
plantigrade and omnivorous, eating anything in the way of fish, oyster,
crayfish, flesh or fowl, and green vegetables especially corn. They have
the peculiar habit of washing their food. They are nocturnal. The limbs
are long and the soles of the fect naked. ‘The raccoon is at home in the
timbered regions of the southern and eastern United States where there are
swamps,” for it loves to play and to fish in the water. It has long active
fingers, and uses its hands as cleverly asa monkey. It makes its home in
the hollow lirnb of a tree. The annual family of five or six young follow the
mother about for a year. In August the “coons” are fat and the flesh is
tender and juicy, and ‘coon hunting” isa great sport. The young are easily

MAMMALIA 359

tamed, but are annoying on account of their curiosity and the skill with
which they open doors with their hands. The fur is much used. The fam-
ily includes also the civet-cats of the Southwest, the kinkajou of the
tropics, and the South American coati.

The bears ( Ur’sidw) are clumsy, omnivorous animals, with thick limbs
and naked-soled, plantigrade feet, bearing strong non-retractile claws.
The tail is short and the hair coarse. The “molar teeth are more adapted to
grinding than to cutting and the flesh teeth are massive and blunt.”” Some
species are especially fond of insects, such as day-flies, grubs, and termites.
The latter they obtain by digging into the nest and sucking them into the
mouth with inhalations strong enough to be heard two hundred yards away.
They are also fond of honey and fish. They live upon the ground, few spe-
cies being able to climb trees. The den may be in a hollow tree or in a cave
in a hillside, either natural or dug out by the mother. Two cubs, not larger
than rabbits, almost hairless, blind, and helpless, are born in mid-winter,
and the mother guards them solicitously. It takes seven years to reach
maturity. Bears rarely breed in captivity. The male bears wander
about singly, “the females are accompanied by their cubs, often as big as
themselves.”

Bears are naturally good tempered. The majority of the instances of
unprovoked attacks, says Hornaday, have been probably by mother bears
who fancied their cubs in danger—even those bears which ate up the chil-
dren in Elijah’s day were “‘she-bears.”! When a bear is aroused it is
exceedingly formidable. It deals killing blows with one of its paws,
having been known to kill a buffalo with one blow. It does not hug its
victims to death. The grizzly flees from man unless cornered. In cold,
snowy countries, where bears are unable to obtain food they pass the winter
in a sort of sleep, living upon their fat stored up in the fall, but they do not
become torpid, as the cold-blooded animals do. In some specics the males,
which hibernate singly, come out from time to time. They do not hibernate
in the tropics nor in captivity, leading us to believe that the winter sleep
of the north is only another adaptation to environment.

According to Beddard, the polar bear hunts “by scent rather than sight
or hearing, both of which senses seem to be somewhat dull.”’ All American
bears, except the polar bear, change their color, being darkest in late summer
and lightest in spring. There are a number of well-marked types of bears,
eight of which live in Asia and Europe, and four, the polar bear, the brown
bear, the grizzly, and the black, live in America. One group is found all
around the North Pole and another group in South America. The oil, fat,
and fir of bears are used.

Not until the Pliocene in the Old World and later in the New did the true
bears (Ursus) appear. So this family, which is highly specialized in some
features and very primitive in others, is among the youngest of the Car-
nivora.

The fur-bearers (Mustel’ide) are blood-thirsty robbers, often killing
many times what they can consume, seemingly from a spirit of mere wan-
tonness. ‘The testimony of the rocks,” says Ingersoll, ‘shows that this
family is either an ancient branch from the civet stock, or that it has sprung
from the same root.” The genus Lutra is widely distributed. It includes
the otter. The front and hind feet are webbed, and the claws on the hind
feet flattened and nail-like.

The North American otter is still occasionally found ‘‘in Florida, Carolina,

11 Kings ii, 24.

360 BRANCH CHORDATA

Canadian provinces, in a few localities in the Rocky Mountain region, and
from British Columbia to central Alaska.”’ The home for the rearing of the
two young is a burrow in the bank of astream. The sea otter (Latar lutris)
feeds largely on sea-urchins and shell-fish, and its molars are flattened and
the tubercles very blunt, for crushing the shells. This animal has been so
much hunted for its exceedingly valuable fur that it has changed its habit
of feeding upon the shore to hunting in the deeper waters, and makes its
bed on floating masses of kelp. It is rare except in Alaska, and is one of the
wildest and wariest of animals. At present the otters are among the most
valuable of all fur-bearing animals, asingle skin of the sea otter having been
sold in London for £250, or about $1250.

The badger (eles) has naked soles and the claws of the fore feet are
much longer than those of the hind feet. The true badger of Europe and
eastward is nocturnal, omnivorous, and burrowing, loving the woods.
The South American badger resembles the European one, but is smaller.
Its three or four young are born naked. Its body, which is about 2 feet
long, is broad and flat, and its legs very short. It has a sullen, savage dis-
position. It feeds on ground squirrels and prairie-dogs. It ranges over the
Great Plains, the Rocky Mountains and westward, and from Mexico to
Alaska. In the United States it is more or less active all winter, being able
to find food, but farther north it is forced to spend the severest portion of
the winter in semitorpidity. There are a number of species in Asia. The
Teledu (Myd’aus melictes), of Java and Sumatra, is said to rival the skunk in
the odor of its secretion.

The skunks (Mephi’tis), of which there are nine species, are widely dis-
tributed in America. They are distinguished by their jet black color,
variously banded, with longitudinal bands or spots of pure white, making
them conspicuous. This is surcly a fine example of warning colors, for both
man and beasts are well aware of the strong offensive odor of the anal se-
cretions which can be ejected for a distance of several feet. Despite this
efficient means of defense the skunk is sometimes devoured by the puma,
the harpy eagle, and the great horned owl. It is destructive of poultry,
but is a destroyer of myriads of noxious insects and mice. The fur is ex-
tensively used, first being dyed.

The marten and weasel tribe is distinguished by a long slender body,
short legs, and cat paws. These small, agile creatures have valuable
fur. The group includes the Siberian sable, the North European marten,
and the Canadian pine marten. The marten is 1S inches long, with a rather
bushy tail of 7 or S inches. It is brown above, lighter below, and varies
according to the age, sex, and season. “The winter fur is thick, soft, 13
inches deep, of the richest hue, and has scattered through it coarse, black
hairs which the furrier pulls out.””. The six or eight young are born high up
in a hollow tree or ina rocky crevice. The Canadian marten is not a poultry
thief nor wanton murderer, but kills what it wants to eat of squirrels, hares,
and grouse, trailing them with the nose to the ground like a hound. Few
animals will eat the marten unless extremely hungry.

‘The mink-is small and of a chocolate or yellowish-brown color, with a
round hairy tail. It is scattered throughout North America along the banks
of streams. It feeds chiefly upon birds and is a “wanton murderer.” The
black-footed ferret. is nearly always found in the prairic-dog villages. The
English ferret is simply a domesticated varicty of the polecat (Puto’rius
fetidus) 1

' Beddard, p. 436.

MAMMALIA 361

The_weasel is the smallest. animal of the group. The body is very long
and “no thicker than a man’s thumb.” Its fur changes from brown in
summer to white in winter. This winter fur is known us ermine, and comes
from Alaska, Canada, Lapland, Russia, and Siberia. It is used not only
for ladies’ garments, but for the robes and crowns of kings. The smallest
of all Carnivores is Putorius rixosus, of northwestern Canada. It is only
6 inches in total length and brown to the tip of its tail. In all other specics
the end of the tail is black. The change of color to white helps to retain the
body heat, and helps also to conceal the animal from its enemies and its
prey. Poulton believes that the cause of this change of color is the lower
temperature acting upon the skin, and that existing dark hairs become white
at the tips. Others maintain that in cold regions the summer pelage is re-
placed in winter by hairs which come in wholly white, while in warm regions
the new winter coat is brown. However, Doctor Coues says he has scen
many autumnal skins which were white at the roots and dark at the tips.
In any case, natural selection has preserved those individuals having the
power of changing the color of the fur until this character is now general.

The dog family (Canide) is universally distributed, with the exception
of New Zealand. These animals have a simple, cylindric cecum and usually
five toes. Perhaps the most striking feature of the family is the bladder-
like inflation of the auditory bulla, that part of the skuil containing the
internal ear. This apparatus and sense is perfected in the dogs. Many of
this family are familiar.

There are several genera, but the principal one is Canis, including our
dogs, wolves, foxes, and jackals. Huxley divides them into fox-like and
wolf-like dogs. The foxes are more active than the wolves, with a “broad
skull, sharper muzzle, larger ears, a more bushy tail, and, usually, longer
fur.” They are notably clever and quick witted, and often show skill in
meeting new situations made by the advent of man.

The typical fox is the common red fox (Vulpes fulvus), of wide distri-
bution. Our American form varies from the typical yellowish red, darkest
on the back and shoulders, to a very bright or very pale yellowish red.
It may have the markings on the spine and withers very dark and distinct,
making it a “‘cross-fox,” or be totally black with a white-tipped tail, or black
with the tips of most of the hairs white, giving the fur a frosted or silver
appearance. Either of the last two cases is called ‘‘silver fox.” These rare
and valuable variations may occur in the same litter with the normally
reddish ones. Foxes feed upon ground birds and their eggs, rodents, frogs,
lizards, insects, and fruits. They may be caught by rapid chase, by digging
the burrowing forms out of the ground—for the fox is naturally a burrower—
by stealthily creeping up on them, or by lying apparently dead until the vic-
tim approaches, and then pouncing upon it. While it does sometimes raid the
hen coops, the fox does good service in destroying rats, mice, and gophers.
It sometimes stores its surplus food. Its enemies are all the large cats and
wolves, as well as man and dogs in the so-called sport of fox chasing. The
red fox has a litter of seven or eight young; the southern gray fox, of four or
five. The gray fox is smaller. It climbs trees to get the “sour grapes” and
persimmons, but it cannot adapt itself to the prairies. The arctic fox
(Vulpes lagopus) furnishes another example of color variation under the
influence of a different climate. In the extreme north it is snow white all
the year round. A little farther south it is brown, with the under parts
lighter in summer and white in winter, while in the southern part of its
range, as in the Aleutian Island and parts of Greenland, it is most often bluish

362 BRANCH CHORDATA

orslate gray. That these are not different species is proved by the fact that
occasionally one or two “blue foxes” occur in the litter where all the rest
become white; for all the young are blue. The arctic fox is valued for its
fur. The blue variety, being less abundant, is worth twice that of the white.
Commercial companies are, therefore, making attempts to breed these foxes
on the islands of the Alaska coast. In the extreme north the arctic fox
stores its food in summer for the long, desolate winter. There are a number
of other species of foxes.

The wolf-like dogs include the dogs, jackals, and wolves. Domestic dogs
of to-day comprise about two hundred breeds. They are owned by natives
of all countries except the South Sea Islands. They have been associated
with man for thousands of years, their remains having been found in Danish
kitchen-middens, in the Swiss lake-dwellings, and in the remains of the
Bronze Age in Europe generally. It is only since the invention of firearms
that hunting with dogs has become general, as stealth was necessary to the
successful hunter and the dog might frighten the game. It might have been
used in running down such animals as the deer, but it seems from obtainable
evidence that it was used for the protection of the camp, to watch while the
master slept, and to give the alarm if beast or man came near; or it served as
food in time of necessity. Authorities vary in their opinion as to what stock
gave rise to the domesticraces. ‘ The jackal, bunasu, and the Indian wolf
have been suggested as ancestors. It is probable there has been much
mixture and that different wild types have been selected by man in various
countries.”’! The intelligence of dogs and their ability to learn by training
are well known and utilized by breeders and dealers.

There are many species of African and Oriental jackals. Some feed
chiefly on carrion, but also commit depredations upon the hen roosts and
farmyards; others live upon figs, and others chiefly upon fruits. Their cry
is a long howl, ending in a series of short yelps. Anderson says “‘they often
congregate near one’s tent and make the night hideous with their howls.”

The wolf of the present time is distributed over most of Europe, northern
Asia, and North America, wherever a rough country affords it shelter.

Hornaday says “‘there is no depth of meanness, treachery, or cruelty to
which they do not cheerfully descend. They are the only animals on earth
which make a regular practice of killing and eating their companions and
devouring their own dead. But in the face of foes capable of defense even
gray wolves are rank cowards, and, unless cornered in a den, will not stop
to fight for their own cubs.”’ The five or more sooty brown whelps are born
in a cave (which is often dug by the mother) early in May, but usually only
two or three survive. In winter wolves form a pack to assist each other in
attacking the prey. Travellers through infested regions have been boldly
pursued and killed by them. The prolonged deep-chested bass howl, which
“multiplies itself by its rapid echoing until one wolf sounds like a dozen,”
is not broken into a bark like that of the coyote. The timber or gray wolf
(Canis occidentalis) is very much like the European (C. lupus). It can adapt
itself to almost any situation, being at home in the timbered regions or on the
treeless prairies of the West, in the evergreen or on the treeless prairies of
the West, in the evergreen forests of British Columbia, and on the desolate
barren ground of arctic America. Its winter coat is long and shaggy, and
varies from the standard gray (black and white mixed) to black in Florida
and rufous in Texas, while in the North it varies from black to the predomi-
nating white color of arctic animals.

1 Beddard, p. 423.

MAMMALIA 363

The coyote (C. latrans) (Fig. 292)of the western plains is one-third smaller
than the gray wolf, and carries the tail low, as befits a coward, while that of
the wolf points above the horizon. The cry is a dog-like yelp, half howl,
half bark. They feed upon prairic-dogs, ground squirrels, sage grouse, and
rabbits, and, probably, sheep and pigs. They are not dangerous to man.
The five to seven puppies are born in deep holes or washouts in the banks of
streams in May.

The cat family (Fe’lid@) includes lions, tigers, cats, and the hunting leop-
ards. The distribution is worldwide, with the exception of Australia and a
good deal of the Australian region. In genus Felis the claws are retractile.

The lion (F. leo) differs from all others by the possession of a mane by
the adult male. The largest lions come from south Africa. The adult is
uniform pale tawnish or yellowish gray. The young is spotted. It inhab-
its Africa, India, parts of western Asia, and formerly ranged into Europe.

Pasa a sates

U.S. D. A., April, 1908.)

ss

Fig. 292.—Coyote. (Circular 63, Biologic Survey,

It is mainly nocturnal in its habits, though it often feeds in daytime or at
dusk, as the animals go to the spring for water. It feeds on anything it
can capture, or even on carrion. The male may hunt alone, while his mate
cares for the two to five whelps or cubs in some dense cover, bringing the
food to his mate. It is said, however, that the males eat at the first table,
leaving the rest of the family to take what is left. When the cubs are old
enough the mother joins in the search for prey, which is usually obtained
by “stalking,” that is, by stealthily creeping up through the tall grass and
leaping upon it, striking a fell blow, and clutching, it with claws and teeth.
Failing in this, they sometimes give chase. Lions cannot climb trees.
“The choice of mate seems to lie with the female,” says Ingersoll, ‘and
the continuance of the union appears to depend on the power of the lion to
hold his fickle spouse to her allegiance.” She tries to flirt with every
new male, but her mate bounds between her and the intruder and then

364 BRANCH CHORDATA

ensues a fierce struggle for possession unless the intruder slinks away.
The female fawns upon the conqueror, whichever he may be. There is
some, though insufficient, evidence, that the male is sometimes a polyg-
amist. Lions will live for thirty or forty years and breed well in captivity.

The tiger (/’. tigris) is about the same size as the lion, the female being
12 or 15 inches shorter than the male. He is more quick, sly, subtle, and
cunning. The tiger is exclusively Asiatic, ranging northward, even into icy
Siberia. Tigers are creatures of the mountains rather than the open plains.
The northern ones are adapted to the cold climate by longer and closer fur.
Tigers ean climb trees and can swim considerably. Naturally, they hunt in
the evening or night, but extreme hunger may drive them to hunt in day-
time. The Malays and Hindus hold them in superstitious terror and oppose
their destruction.

The leopard or panther (F. pardus) is both African and Asiatic. It
varies from almost black to a tawny color. It is spotted with small rosettes
or rings of black surrounding spots of light or tawny color. Some of the
spots are solid black. It is as ferocious as a tiger, but sly and cautious, and
far lighter and more active. It can climb a tree like a cat. It necessarily
preys upon smaller animals than do lions and tigers, playing havoe with
poultry, sheep, goats, dogs, wild birds, monkeys, and wild pigs. Carrion
also furnishes it food. Its ery is a “‘ harsh, measured, coughing roar.” The
snow leopard or ounce (/’. wncia) is a beautiful creature, white, with larger
black spots. It is confined to the highlands of central Asia.

The jaguar (F’. onca) is the largest and handsomest of the American cats.
The head is large and the tail short. It has a golden-yellow coat, marked on
the back and sides with large black rosettes, between which run the narrow
lines of yellow ground color. The spots on the legs, head, and under parts
are solid black. It is found in South America, Mexico, and as far north as
Texas. Hornaday believes that it has the strongest jaws of any member of
the cat family. It is fierce, powerful, and dangerous, but is afraid of man.
It also climbs trees.

The puma (F’. concolor) is found in “all the great western mountain-ranges
and in many tracts of the bad lands of Wyoming and Montana, in British
Columbia, in the Adirondacks and Florida,’ and south to Patagonia.
Hornaday says that although the puma has been known ‘“‘to follow belated
hunters out of curiosity, this animal is less to be dreaded than a savage dog.”
It sometimes screams like a terrified woman or boy; it always flees from man
if there is a way of escape. It isa thin, tall animal of a brownish drab color.

The lynxes of North America are ‘“short-tailed, heavily furred, tree-
climbing cats,” distributed over nearly all the wild portions of the country
north of Mexico, whether forests, mountains, plains, canyons, or even
deserts. They are neither courageous nor pugnacious unless cornered.
The Canada lynx (L. canadensis) has a long pencil of stiff black hairs rising
from the tip of each ear. It has large, hairy paws, and is a good climber.
It swims well, but runs rather poorly on land. A full-grown one weighs
22 pounds. There are two young. The Bay lynx, or wild-cat, is usually a
mixture of rusty red, gray, and blackish brown, with red prevailing. — It
is found in both the Hast and West and in Texas. No lynxes are found in
the lowlands of tropical or South America.

The domestic cat, says Beddard, is regarded as the descendant of the
eastern F. caffra or the closely allicd PF. manteulata, or from both and from
their interbreeding with the wild-cat of Europe, for many species of cats,
even the lion and tiger, it is said, willinterbreed. Whatever was the source,

MAMMALLA 365

they have been crossed and interbred with many varictics before reaching
the “house cat’’ of to-day. The domestication of the cat is very remote.
A tablet. dating from 1600 B. c. has on it the representation of a cat.
“ Rows of skilfully wrapped mummics of cats in richly adorned cases” may
be seen at Cairo, showing that ancient Egyptians must have held them
in reverence.

The hunting leopard (Cynlu’rus jubatus), of Africa, India, Persia, and
Turkestan, has longer legs and less retractile claws than the true cats. In
India it has been trained for ages to capture game for its masters.

The civets (Viver’ridw) are comparatively small animals, with usually
five digits and with non-retractile or very incompletely retractile claws.
There is usually a scent gland, which is the source of the civet perfume.

The genus hyena ( Hyen’id@) comprises three living species. The body
is bulky, the legs strong, the head big and dog-like, and the jaws strong.
They are nocturnal scavengers, though sometimes seizing small animals.
They are found in Europe, Asia, and Africa, but not in America.

Geologic Distribution —‘ The first Carnivores appear in the
order Creodon’ta, plantigrade forms of slightly differentiated
dentition (no carnassials); they present marked resemblances to
marsupials, insectivores, as well as to the Condylar’thra, the an-
cestral ungulates.”! There is a long gap, both in time and
structure, between the few Eocene carnivores and their supposed
ancestors among the Creodonts, which are generalized types
as hinted above. In the late Miocene the present groups
of Carnivora become more or less distinct by the intermediate
“ stock forms becoming extinct.”

Use to Man.—Hundreds of lion skins are sold annually,
thousands of wild-cat skins, and more than a million skins of the
common cat are made into cheap furs.

The aquatic carnivora (Pinnipe'dia) include the seals, sea-
lions, and walruses. They have acquired a somewhat fish-like
form. The limbs are flattened into broad flippers, the five
long toes are webbed, and the nails are often rudimentary.
Molars and premolars are similar (carnassial absent).

The northern fur seal (Ota‘ria ursina) and the Patagonian maned sea-lion
(O. jubata) belong to the genus Otaria, which is mainly antarctic. The har-
bor seal is the common form along the Atlantic Coast. There is a colony
of sea-lions on the Pacific. In the fur seals there is a dense, soft under fur.
The Alaska seal has its summer residence and breeding grounds in one or
two islands of the Behring Seca. In winter they are absent from these
islands, and “their whereabouts is a matter of much speculation.”” They
live in groups, consisting of a single old male and five to twenty females.
The young males a year or two old herd by themselves, maturing at the

’ Hertwig.

366 BRANCH CHORDATA

age of six. The females mature younger. The males ure six or eight times
as large as the females. The rivalry between the males is intense. In the
fighting, great strength of neck and jaw is used. The fur seal industry rep-
resents many millions of dollars.!

The walrus family (Trichech’id@) belongs to the aquatic carnivores. The
walrus is arctic and circumpolar. It is characterized by the enormous
canines of the upper jaw, which form tusks sometimes 30 inches long. The
walrus is from 10 to 12 feet long, and, though it can move about on land, it
is very ungainly. The hair is short and scanty. As in the true seals, there
are no external ears. The flesh, fat, and hide are much used in the North.

The true seals (Pho'cidw) have the nostrils in a dorsal position and have
no external ears. The hind limbs are bound up with the tail and are useless
on land. The largest is the elephant scal, about 20 feet long. The male
has a proboscis of about 15 inches. This seal is mild and inoffensive except
when enraged, and, of course, during the breeding season. The whole
animal is invested in a mass of blubber which is as thick as that in a whale.

Order IX. Insectiv’ora.—These are small, plantigrade, long-
snouted, chiefly nocturnal mammals, which feed on insects and
earthworms. The eyes are small or hidden by fur. The clav-
icle is usually present; the cecum, absent or minute. As a rule,
there are five digits. All of this order are provided with sharp
teeth. The front teeth in both jaws are inclined outward, being
less adapted for seizing the prey. The brain is of simple struc-
ture, the hemispheres usually smooth.

Hedgehogs are covered with spines, but they are not barbed as in the
porcupine, and they are firmly attached. Hedgehogs feed upon insects,
chickens, young game birds, and even vipers. They are less than a foot in
length, about the size of a big rat. They disappear in hot weather, and come
out in rainy weather. They hibernate in winter. E. ewropeus defends it-
self by rolling up into a ball, with its head tucked between its fore feet and
the hind feet drawn up close together, thus presenting, on all sides, its sharp
spines to its enemies, few of which will attack the hedgehog. Hedgehogs
are not found in the Western Hemisphere. Their voice is described as a
sound between a grunt and a squeak.

The shrews (Soric’id@) (Fig. 293) are small, nocturnal, fur-coveied in-
sectivores, which are often mistaken for mice, but the teeth show they are
not rodents. They are of wide distribution, but. are not found in Australia
nor in South America. Several specics are found in the United States.
S. personalus is chestnut brown, with large ears and short tail. They are
thinly covered with hair. Their length is 2¢ inches; the tail, linch. They
are found from Massachusetts to Alaska. The water shrew (S. palustris)
is the largest of our shrews, measuring 6 inches, with the tail 24 inches long.
The lesser shrews of Great Britain are burrowing, nocturnal animals, and
secrete a disagreeable odor for protection. They are among the smallest
of all mammals.

1 Sec Hornaday, or Jordan’s “Report of the Fur Seal Investigation,”
1896-97.

MAMMALIA 367

The moles (Tal'pide) are subterranean animals, with bioad front feet
and vestigial eyes. The common prairie mole (Scalops aquaticus machrinus)
(Fig. 294) is well known by its habit of burrowing in gardens for earthworms
and grubs. It eats also the roots of vegetables. Its powerful front limbs
are clawed for digging. Its hind limbs are weak, the tail short, and the nose
pointed. The star-nosed mole of the eastern United States (Condylu’ra

Fig. 293.—Common shrew. (After Coues.)

cristola) has the tip of its snout encircled with fleshy projections. Talpa is
an Old World form. The Russian Desman (Myog’ale moscata) lives in
burrows in the banks of streams. It feeds on fresh-water insects and larve.

An Oriental insectivore is an aberrant form. It is much larger than most
of the order and has an integumentary membrane, connecting the neck with
a fore limb, the fore limb with the hind limb and the hind limb with the
tail.

Fig. 294.—Common mole (Scalops aquaticus), Linn. (After Coues.)

Geographic Distribution —This order is represented in every
region except South America and Australia. The moles are
confined to the temperate regions of the Northern Hemisphere.
Hedgehogs are not found in the Western Hemisphere nor in
Australia.

368 BRANCH CHORDATA

Geologic Distribution —In North America they date back to
the Eocene Period. The Miocene Palwoerina’ceus differs so
little from the existing genus, Hrina’ceus, that the latter may be
called “ one of the oldest living genera of mammals.”

Use to Man.—Many mammals of this order have fine soft
fur. They are also of value as insect destroyers. A single mole
is said to devour twenty thousand insects annually.

Order X. Chiroptera.—The bats have many points of resem-
blance and: structure with both lemurs and insectivores. But
they are distinguishable from all other mammals by their power

Fig. 295.—Skeleton of pteropus: St, Sternum; Cl, clavicle; Sc, scapula;
HA, humerus; R, radius; U, ulna; D, thumb; Ji, ilium; P, pubis; Js,
ischium; /’e, femur; 7’, tibia; F, fibula. (After Owen.)

of zigzag flight. ‘“‘ The wings” (Fig. 295) consist of an integu-
mental membrane, supported by the digits (two to five), which
are greatly elongated and are folded together like the ribs of an
umbrella when the wings are folded. A membrane between the
hind legs and tail, when present, is used for steering.

The expanse of wing, compared with that of the body, is
greater than that of most birds, but the muscles are weaker.
The first digit, or thumb, is short, free, and strongly clawed,
“and sometimes a sucker, by which bats scramble about rocks
and trees, recalls the similar organ in that primitive lizard-like

MAMMALIA 369

bird, the Archewopterix.”” The bones of this order are slender
and light. The skull and teeth present many extraordinary
variations. The radius is long and curved, the ulna is rudiment-
ary, and the knee is directed backward. The sternum is keeled
for the attachment of the pectoral muscles, the chicf muscles of
flight. The ribs are flat and sometimes ankylosed together by
their margins. The fibula is rarely fully developed. The hind
limbs are small and serve as a means of hanging the body head
downward in rest or sleep, but are almost useless for walking.
The skull is almost as large as the chest. The ears are sometimes
much longer than the head. The nostrils are wide and are often
surrounded by highly complicated sensitive membranes, which
sometimes give the face a comical or even hideous expression.
These are often more strongly developed inthe male. The cheek
teeth of the insectivorous bats terminate in sharp points, and
are designed for cutting to pieces the hard parts of hard-shelled
insects. The fruit-eating bats have molars with rather smooth
crowns, While the vampires (Fig. 296, p. 371) have molars
with scissor-edges and large canine teeth with sharp, cutting
edges. The eyes are minute except in the fox bats. The wing
membranes are sensitive, containing intricate network of blood-
vessels, nerves, and ‘‘ end organs,” and thus, by the aid of their
sensitive wings and sensitive membranes on the face, bats are
enabled to fly without touching bodies in their way, though they
be in utter darkness or when their eyes are so minute and fur-
buried that they could not detect the intruding object. The
cerebral hemispheres are smooth and do not extend over the cere-
bellum. Bats are small and nocturnal and generally insectiv-
orous, generally feeding on the wing, thus they are beneficial.
Some are fruit-eating, and others, as the vampires of South
America, are blood-sucking, attacking warm-blooded animals,
and will even withdraw a quantity of blood from a sleeping man.
There is nothing whatever to fear from the bats of the United
States, for their claws and teeth are weak. The fur is usually
brown or gray, ‘‘ but a few Oriental species are mottled or varie-
gated with orange, bright yellow and black,’ as is shown by
the “painted” bat of Ceylon. This bat hides by day in the
folded leaf of a plantain, and when disturbed, looks more like a
butterfly than a bat. Mr. Swinhoe, a naturalist long residing
24

370 BRANCH CHORDATA

in China,! says that these colors are highly protective, for the
brilliant bat inhabiting Formosa resorts to the longan tree.
This evergreen tree always has some portion of its foliage decay-
ing, making these dying leaves orange and black, while the fruit
is reddish yellow. Thus the orange and black bat, suspended
from the branches, is concealed from its enemies by its protect-
ive resemblance. Owing to their nocturnal habits very little
is known of the activities of bats. ‘‘ We know that in the winter
some of our species live in caves in a semidormant condition,”
and Dr. Hart Merriam has proved that some species do migrate
in fall and spring. All bats living within the snow limit of the
Temperate Zone must either migrate or hibernate, for the fruit-
eating bats could find no food, and the delicate wings of the
vampire, which might find food, would be frozen stiff in zero
weather, so the latter are chiefly tropical. Bats usually inhabit
caves, a million sometimes hibernating in one cave. The thick
layer of guano on the floor of the cave may represent the deposit
of centuries. Bat guano is a valuable fertilizer. In warm
countries bats live in hollow trees. The ery is a shrill squeak.
They are widely distributed, being found on islands where there
are no other mammals. The occurrence of the same genus of
bats in India and Madagascar has led some to believe that there
must have been at one time some connection between these
countries, as these slow-flying creatures could hardly have
traversed these vast stretches of ocean by their power of flight
alone.?, However, Hornaday tells of a British long-eared bat
which was found clinging to the rail of an Atlantic steamer 30
miles from land, with no breeze going from the land.

Bats are divided into two groups: the large diurnal (.eg’a-
chirop'tera), or fruit-eating bats, and the nocturnal (.VW7’cro-
chirop’tera), or insect-eating bats.

Megachiroptera.—The ordinary fruit bats or fox bats number about forty
species. The fur is fox red, the muzzle long and pointed. The eyes are
big and the ears upright, giving them a fox-like appearance. They live in
colonies of from five to fifty. Hornaday killed some having 40 inches
spread of wings. He says “of all creatures that fly, none are so uncanny
when outlined against the sky as the big black-winged, half-naked flying
fox (bats). They suggest demons and calamities.” The fruit-growers of
California, being fearful of their introduction into the United States, have

1 Ingersoll, p. 63, * Beddard, p. 525.

MAMMALIA 371

secured a law prohibiting their importation even into zoélogical gardens.
In the Ethiopian region this family is represented by the large, grotesque,
hammer-headed bat (Hpomoph'orus). Its head, particularly the muzzle, is
enlarged, giving it a resemblance, in profile, to the head of a moose. The
larger fruit bats are eaten by natives of their countries and even relished by
white men. They make affectionate pets, but it would seem strange, weird
ones.

Microchiroptera includes five families. Here belong the leaf-nosed bats
already mentioned, the “‘bonneted bats,” and the naked bats, the vampires
(Fig. 296), and the common smaller bats. The naked bats of Borneo have
thick, leathery, elastic skin. A scent gland for defense is situated between
two folds about the neck. The most remarkable thing is the mammary
pouch under each arm—a wide pouch of rubber-like skin m which the young
are carried until able to fly. The mammary gland is in the lower portion of
the pouch.

AY

Fig. 296.—Head of Phyllos'toma (Vampyrus) spectrum. (Claus.)

‘Of the vampires or blood-suckers, the javelin bat (Phylos’toma hastatum)
bites horses, cattle, and even sleeping man. The sharp-edged, dagger-like
teeth make a small round hole in the skin, from which the vampire draws
the blood by mouth suction. The blood sometimes flows freely after the
bat has left its victim, but there is no poison attending a wound. The
digestive organs of the vampires are extremely modified, these bats living
upon predigested liquid food. The gullet is too narrow for any solid food to
pass through and the stomach is intestine-like.

The common bats (Vespertilion’id@) range over all parts of the world, and
number over two hundred species. Most of the bats of the United States,
about eighteen species, belong to this family. They are very common
along the Atlantic coast and there are several species along the Pacific.
The commonest is the little red bat, which flies about in the early twilight.
It is constantly on the wing from sunset until dark. In its flight it can turn
abruptly and with great accuracy. It is remarkable that it can turn and
double so quickly and dart in all possible directions without striking any-
thing. The gray bat of the northeastern United States and Canada and the
big-eared bat of the South Atlantic coast are members of this family. The
North American bats never make any nests. The little bats are born in
crannies, and, from the first, cling about the mother’s neck when she
chases the ‘numberless little flying things of the dusk. When there are
twins, the male takes his share of the responsibility.”

372 BRANCH CHORDATA

Geologic Distribution.—Bats appear for the first time in the
Eocene Epoch, according to the records of the rocks.!

Order XI. Prima’tes.—This order includes all animals with
hands and hand-like feet. With but a few exceptions the
members of this order inhabit the tropics. Except in man, they
reach their highest development near the equator. Hornaday
says that there is no human being of sound mind to whom the
human likeness of the lower Primates does not appeal. They
are, at any rate, very much like man in their structural develop-
ment. Asa rule, they have five fingers and toes, each covered
at the tip by a flat nail. The inner finger or toe, or both, are
opposable, making the hand, and often the foot, a grasping organ.
The feet are plantigrade. The limbs are quite free from the
body, as compared with those of other chordates. The skull of
the Anthropot'dea is characterized by the bony partition between
the orbital and temporal vacuities. The stomach is simple.
The cecum is always present and sometimes large. They are
chiefly arboreal, except terrestrial man.

The sub-order Lemuroi’dea includes the aye-aye, tarsier, and
the lemurs. The head lacks the human-like expression, being
more like a fox, with a sharp muzzle. There are no cheek
pouches. The tail, which is never prehensile, varies from none,
in Loris, to the long and bushy tail of the “ aye-aye.” The
thumb and great toe are well developed and the second toe has
a sharp nail unlike the flat nail of the other digits. The brain
case is small and the temporal and orbital fossze are in com-
munication. The placenta is non-deciduate. The vermiform
appendix is never present and the cecum varies in length.
They are now found only in Madagascar, tropical Africa, and the
Orient. In the Tertiary Period the ancestors of these animals
were scattered all over the globe.

The lemurs (Lemur’ida) have round heads with fox-like muzzles, small
ears, and a long tail (Fig. 297). The wooly fur, which is often beautifully
tinted, is soft und thick. In size they vary from that of the squirrel to that
of the cat. They are omnivorous, and, as a rule, diurnal or crepuscular.
They are found in Madagascar. In trees they run about on all fours, but on
the ground they wilk erect on their hind legs. The one or two young are
earricd about by the mother as they cling to her breasts, or, later, ride upon
her back. One of the most interesting is the ring-tailed lemur, which

1 Scott’s ‘‘Geology,”’ p. 506,

MAMMALIA 373

scrambles over the rocks, its leathery palms being furrowed with sucker-
like grooves, enabling it to go where man cannot. The ruffed or black and
white lemur is perhaps the most beautiful. It is the size of a large house cat,
has a long tail, and is clothed in long, soft, silky, fine fur. The mouse lemurs,
dwarf lemurs, and fat-tailed lemurs estivate during the hot and dry seasons,
curling up in their nests, just as northern animals do in hibcrnation.
“They go in fat, subsist by absorption of this stored tissue, and come out
thin and weak”’ at the approach of the rainy season. Lemurs are all per-
fectly harmless, but their weird actions, big eyes, and loud cries have led to
their being reverenced and feared by the superstitious natives.

The female aye-aye constructs a
globular nest in a tree for the rearing
of her single offspring.

Sub-order Anthropoidea differs
from the lemurs in having the
mammary glands always tho-
racic, the orbital and temporal
fosse separated by bone. The
cerebral hemispheres are highly
developed, almost or quite con-
cealing the cerebellum. There
are over two hundred tropical
and subtropical species.

American monkeys (Platyrrhi’na)
differ from the Old World forms in
having the nostrils directed downward
and separated by w broad septum.
As a rule, they are also smaller and
have but thirty-two teeth. The tails
are usually long and prehensile. No
American form has cheek pouches.
Most of them are arboreal. All
American monkeys une small, varying
in size from that of young kittens or 1. ;
chipmunks to 20 ‘cali Tone They Fig. 297.—Otolicnus galago of Af-
are hairy or woolly. One baby mon- "2. (From Vogt and Specht.)
key is born to each female each year.

The marmosets are lowest in the scale of development, indeed, they
sometimes look very little like monkeys. They range from southern
Mexico to southern Brazil. They are small, delicate creatures, with hair-
less faces, large, bright eyes, and long tails. In some species the long silky
hair stands up on the head like a white ruff. The digits are, for the most
part, clawed, the great toe only bearing a flat nail. They are arboreal, but
the tails are not prehensile.

The second family of American monkeys (Ceb’id@) is distinguished from
the marmosets by thirty-six teeth, and by the generally long and prehensile
tail, which is naked on the under side of the end.

374 BRANCH CHORDATA

The Saki monkeys (Pithe’cia) of tropical South America east of the Andes
aye re) bushy, non-prehensile tails, and, sometimes, a long, black chin

eard.

The squirrel monkeys (Sai’miri) are little creatures with a long head, the
occiput projecting. The proportions of the cranium, as compared with the
face, are greater than in other monkeys orin man, They are gregarious and
arboreal, feeding upon insects, small birds, and eggs.

The howlers are the most hideous looking of the American monkeys and
have the least intelligence. The brain is less convoluted than that of the
At’cles. Their howl, made to intimidate enemies, can be heard two miles.

Fig. 298.—Spider monkey. (American Muscum of Natural History.)

The natives hate the howlers and kill them for food, selling the hide to white
traders. The hair is twisted into cordage.

The spider monkey (.téeles) (Fig. 298) is the most typically arboreal
of American monkeys. With its prehensile tail held erect over its head, it
“feels” for a place to grasp, which it does by wrapping the end of its long
slender tail tightly around the branch. It then swings itself far across
toward another limb, which it grasps with its thumbless hands by hooking
them around the limb and thus suspending its body. “They have a very
uncanny look and can come as near tying themselyes into a knot as any liv-
ing mammal can.” They are weak and cowardly. The Mexiean spider

MAMMALIA 375

monkey is the most northern one in America, sometimes coming up to
latitude 32°.

Perhaps the most typical of this family is the genus Cebus of twenty
species, ranging from Costa Rica to Paraguay. The common monkey
of the organ-grinder belongs to this genus. The thumb is well developed.
The color is usually dull brown, but one is brick red and others have white
about the shoulders. They are gregarious. Contrary to the general belief
that they are strictly herbivorous, they are very fond of caterpillars.

“No monkeys ascend high in the Andes nor reach the west coast, and none
are found south of the forests of Brazil or north of south central Mexico.
Fossil remains of monkeys are rare everywhere, and known in the New World
only in the Santa Cruz Miocene formations of Patagonia; and they show
no more kinship with the Old World types than do the existing species.’’!

Old World monkeys (Catarrhi’na) have the nostrils close together and
directed downward. There are open cheek pouches and but thirty-two teeth.
The tails are non-prehensile or even absent. Often there are hard patches
of hairless, bright-colored skin (ischial collosities) upon the haunches.
Catarrhine monkeys are larger and more intelligent than the Platyrrhine
forms. These distinctions are ancient, “since no fossil remains of mon-
keys at all intermediate have so far been discovered, another evidence of
the very early time at which South America became isolated.”

Macaques and baboons (family Cer’copithec'id@) contains eight or nine
genera divided into two subfamilies. The first (Cer’copithect’ne) consists
of rather large monkeys represented by macaques and baboons. They have
cheek pouches in which to store the food. All the macaques but one are
Asiatic. They are from 13 inches to 3 feet long, the male being larger than
the female, with larger canine teeth. They are gregarious, noisy, and active,
“scrambling about rocks, and some swim and dive well.” In some parts of
India they damage gardens. Their dog-like teeth and strong nails are able
to inflict severe wounds. As examples, the bonnet monkey, the Gibraltar
ape, and the pig-tailed monkey may be mentioned. The latter is trained
by the natives to climb the cocoanut-palm tree and to select and throw down
the ripe cocoanuts.

The baboons (Cynoceph’alus) are found in Africa and Arabia. The
African forms vary in size from that of a spaniel to that of a mastiff.
Their stout limbs are about equal, the nose and head are dog-like, and the
canine teeth long and sharp. They are the fiercest of all Primates. It is
said that even a hungry lion will not attack a baboon. The great ischial
collosities are strikingly colored, adding to the ugliness caused by overhang-
ing eyebrows, small eyes, ferocious disposition, and filthy habits. It is
said these collosities attract the kite bird, which mistakes them for raw meat,
and the baboon makes a meal of the bird. The color is blackish or a green-
ish or yellowish gray, grizzled by each hair being ringed with various colors.
The Gelada has a black body and a brown mane, witha gray chest. It looks
like a small lion with a baboon’s hands and feet. Baboons like the open
country and the rocky hills and deserts. They go in troops.

The second sub-family (Semnopitheci’nz) includes guerezas, the langurs,
or Asiatic holy apes, and the Bornean genus Nasalis. They are slender
apes with no check pouches and have a sacculated stomach.

The anthropoid apes (Simi’ide), though chiefly arboreal, walk erect or
semi-erect when they come to the ground. Their hands and feet are fitted
for a half-arboreal, half-terrestrial life. When they put their hands to the

1 Ingersoll, p. 37.

376 BRANCH CHORDATA

ground to aid in walking they rest cpon the back of the knuckles. Cheek
pouches and tail are lacking and the hair is more scanty than in the baboons.
These entirely Old World forms have a vermiform appendix.

The gibbons (Hylob’ates), slender, monkey-like Indo-Malayun forms,
stand at the base of the series. They are the smallest and most arboreal
and their arms are the longest of any of the group, being long enough
to reach the ground even when standing erect. The canines are large in
both sexes and the jaws and nose ure prolonged. The brain is simpler than
in the higher forms. Onc of the most remarkable habits is their descending
flight through the trees, though they never come to the ground. They leap
incredible distances, says Hornaday, catch and swing with their hands, catch
again with their fect, turning again, and so on, by a serics of revolutions
almost as fast as the flight of a bird. The largest is the Sumatran Siamang,
which stands 3 feet tall and is shining black. The gray gibbons are very
timid, but show strong affection for their young and great courage in their
defense.

Fig. 299.—Comparison of skeletons of primates: 1, Gibbon; 2, orang; 3,
chimpanazce; 4, gorilla; 5, man.

The brown orang-utan lives in Borneo and Sumatra, wholly in the
tree-tops, coming to the ground only for water. On the ground it moves
slowly and swings its body along between its arms like a pair of crutches.
In the trees, too heavy for leaping, they swing underneath the branches with
their long arms, ‘‘grasping a limb with their hook-like hands, and swinging
underneath to the next hold, and so on, at great speed.” It subsists upon
wild fruits, fleshy leaves, and shoots of the serew pine. It is shy and uncer-
tain if captured. When young it is easily tamed; when grown, wild and
ferocious. Hornaday says “in 1901 the zoédlogieal park contained four
orangs, all of which were taught to wear clothes, sit in chairs at table, eat
with fork and spoon, drink from cups and bottles, and perform many human-
like actions without nervousness in the presence of two thousand visitors.
Tach of the orangs learned its part in about two weeks’ training, and at the

1 Ingersoll.

MAMMALIA 377

dinner table acted with gravity and decorum.” In captivity young orangs
are affectionate as children and are fond of their human friends. At night
the wild orang makes a nest to sleep upon by breaking off leafy branches
and laying them crosswise in the forked top of a sapling, where it lies flat
upon its back, grasps the branch firmly in cach hand and foot, and is rocked
to sleep in the tree-top.

The chimpanzee (Fig. 300) has a “ brain, face, ears, and hands
more man-like than those of any other ape.” Its face, cars,
hands, and feet are naked. It has a large brain and a higher

Fig. 300.—The chimpanzee, variety Tshego. (From Brehm’s ‘‘Thierleben.’’)

intellect than any of the Primates below man. It is bright and
cheerful and, having a good memory, is easily taught. The
young are affectionate, but the old males are dangerous. There
are at least two species. They are natives of Africa. Mated
pairs seem to remain together permanently, and missionaries,
when they tried to teach that polygamy was wrong, have been
told by the natives “that they did not wish to be like apes.”
They spend much time hiding in thickets in family groups,
sometimes gathering in such numbers as to do considerable
damage to young bananas. They are crepuscular. They show

378 BRANCH CHORDATA

great affection for their families, the father often taking the baby
from the mother and carrying it, especially in dangerous places,
and they seek to assist one another when hurt or in trouble.
They seem to delight in noise, uttering loud shrieks and howls,
and drumming with sticks on resonant logs. This is the only
employment of an instrument or tool, and, in itself, shows a wide
difference between the chimpanzee and the lowest human savage.

Fig. 301.—Gorilla engena. (Vogt and Specht.)

A rude platform of branches is built for the family bed, the
father, perhaps, sleeping curled up in a crotch of the tree be-
neath it.

The Gorillas.—Both in kind and number “‘the bones below the
skull are the same in the skeletons of man and the gorilla.
They differ only in their proportions” (Fig. 299, 4). The widest
differences are in the skulls. In the gorilla the high forehead
and intellectual faculties so characteristic of man are entirely

MAMMALIA 379

wanting, indicating a low order of intelligence. ‘‘The long and
powerful canine teeth are alone sufficient to proclaim the savage
wild beast.”” The gorilla is not teachable like the chimpanzee,
but is sulky and ferocious. The gorilla is the only ape that walks
erect. Its arms are relatively short and its legs long. Its
hands reach a little below the knees when standing erect. It
has big feet and a pronounced heel. The digits are webbed.!
The brain is larger than that of the chimpanzee, but so is the
body. The great similarity of structure to that of the human
body is due largely to the plantigrade walk and the terrestrial
life. The gorilla is more primitive than the chimpanzee and,
therefore, nearer to the common ancestral stock. It is found in
a small area in West Africa on the equator, and between the
Gaboon and Congo Rivers. Hornaday declares that if the head
of a chimpanzee were placed on the shoulders of a gorilla, we
should have the “ missing link,’’ and that if the missing link
is ever found, it will be in the “ Tertiary deposits of the fertile
uplands that lie between the gloomy equatorial forests of the
black apes and the bushmen of South Africa.”

Man.—Fossil remains of a man-like ape, Anthropopithe’cus
erectus, have been found in the upper Pliocene of Java. It is
generally thought that these fragments belong to an exceed-
ingly large gibbon-like animal having an enormous cranial
cavity and a brain nearly equal in size to that of some of the
savage races of man to-day. There is no doubt that man
lived on the earth at the beginning. of the Pleistocene times,
and it is thought by many anthropologists that he lived in the
latter part of the Tertiary Period, though this has not been
satisfactorily proved.

The family Hominide contains but a single genus, Homo,
and one species, H. sapiens. The different varieties of this
species are now generally classified in three great groups:
the Ethiopian, of Africa; the Mongolian, of Asia; and the Cau-
casian, of Europe. Man is distinguished from other primates
by a less development of hair on the body, by the erect walk,
and by the consequent modification of the hind limbs and feet
(he is a true biped). The face does not project so much as
that of the anthropoid apes. The skull of man is a smooth,

1 Beddard, p. 572.

380 BRANCH CHORDATA

rounded case, while that of the apes is smaller and deeply ridged
and contains a smaller brain. Man’s outstretched hand does
not reach the knee and the thumb is much more useful. The
hallux (great toe) is not opposable. There are no laryngeal
pouches. ‘‘ The minute diverticula, the ventricles of Morgagni,
alone remain to testify of a former howling apparatus in the
ancestors of man.’’!

Man has the power of articulate speech and the faculty of
reason. As to whether this vast difference in reason be one
of kind or degree, psychologists disagree, but all concede that
the reasoning power of man is far in advance of that of any
other animal.

Man’s superiority over animals lies in his highly developed
powers of abstract thought, reason, and will. Through these
powers he is able to adapt himself to his environment, make a
new environment, or migrate to one better suited to his needs.
He can control the lower forms of animal life and modify them
by artificial selection and breeding to satisfy his wants. From
them he procures clothing, leather, food, ornaments, weapons,
.. fertilizer for his land, and materials used in his houses. He
uses them as beasts of burden or as means of travel. Through
undue use or slaughter he has caused the extinction of various
species.

The student has missed the greatest value of the study of
zoblogy if he has not discovered that the great underlying
principles which permeate and control all animal life from the
lowest to the highest forms necessarily apply also to the life,
development, and history of mankind. Descent with adaptive
modifications is amply illustrated in the descendants of one
man during his lifetime. The influence of environment,
growth and decay, heredity, variation, adaptation, the survi-
val of those best adapted to conditions in the physical or the
business world, the strengthening of powers of body or mind
by use, the degeneration of powers by dependence upon others,
the sacrifice of the parent for the offspring everywhere seen in
nature, or the triumph of altruism over egoism in the service
of one’s family or his fellow-men—these are some of the bio-
logic principles directly applicable to man.

1 Beddard, p. 589.

MAMMALIA 381

Classification.—
Order. Examples.
I. Monotrem/ata. Duckbill, Spiny Ant-eater.
II. Marsupia’lia. Kangaroo, Opossum.
III. Edenta’ta. Ant-eater, Armadillo.
IV. Sire’nia. Manatee, Dugong.
V. Ceta’cea. Whales, Porpoises.
VI. Ungula’ta. Cattle, Sheep, Deer, Horses.
VII. Roden’tia. Rabbits, Squirrels, Prairie-dogs.
VIII. Carniv’ora. Cats, Dogs.
IX. Insectiv’ora. Moles, Shrews.
X. Chirop’tera. Bats.

XI. Prima’tes. Apes, Monkeys, Man.

THEORIES OF DEVELOPMENT

Origin of Life——Many scientists to-day advocate that life
is the action of chemical and physical forces in connection with
a peculiar substance called protoplasm. But no one has yet
been able to explain all the phenomena of life by means of these
forces. Until this is done, we must believe that life from life
is the universal rule, or that no living organism originates except
from some pre-existing living form.

Protoplasm is the physical basis of all life, both plant and
animal, and without this complex substance life cannot exist.
It is a protein which is known only as a product of living sub-
stances.! It is chemically and physically unstable, but it is
impossible to obtain a satisfactory chemical analysis since the
dead material differs from the living protoplasm both in its
power and structure.

There is little direct proof of the character of life in the
Archean Era, but it must have been marine. Since plants
usually feed upon inorganic matter and animals cannot manu-
facture organic compounds from inorganic ones, and as plant
life is thus a necessity for the existence of animal life, it is
thought that plant life may have been first. However, the
view that plant and animal forms originated side by side and
have developed along diverging lines is common.

Since the simplest form of life to-day consists of a single cell,
it is believed that primitive life began as a single cell.

The Cell Theory.—Cells were first described by Hooke, an
Englishman, in 1665, and were so named from the resemblance
of the compartments in the structure of a piece of cork to the
cells in a monastery. Schleiden, in 1838, showed that plants
were composed of cells, and in 1839 Schwann discovered the
same general fact concerning the bodies of animals, thus re-
vealing the common plan of organization of plants and animals.

The cell theory involves: (1) that all organisms are made up

1McFarland’s “ Biology.”
382

CELL DIVISION OR MITOSIS 383

of single cells or combinations of cells; (2) that all organisms
begin life as a single cell, giving rise in metazoans to a body of
more or less complexity, and (3) that the function of this com-
plex (multicellular) organism may be expressed in terms of the
activities of the individual cells of which it is composed. The
third proposition may need some modification. “It was
through the cell theory that Kélliker, Remak, Nageli, and
Hofmeister opened the way to an understanding of the nature of
embryologic development, and the law of genetic continuity
lying at the basis of inheritance. It was the cell theory again
which, in the hands of Goodsir, Virchow, and Max Schultze,
inaugurated a new era in the history of physiology and pathol-
ogy, by showing that all the various functions of the body, in
health and in disease, are but the outward expressions of cell
activities. And at a still later day it was through the cell
theory that Hertwig, Fol, Van Beneden, and Strasburger solved
the long-standing riddle of the fertilization of the egg and the
mechanism of hereditary transmission. No other biologic
generalization, save only the theory of organic evolution, has
brought so many apparently diverse phenomena under a com-
mon point of view, or has accomplished more for the unification
of knowledge. The cell theory must, therefore, be placed be-
side the evolution theory as one of the foundation stones of
modern biology.’

Cell Structure.—In the typical cell are found the following
parts: (1) the cell wall; (2) the cytoplasm, or cell substance,
which includes the plasma (that is, the living protoplasm around
the nucleus) and the chylema, or “cell-sap’’; (3) a nucleus which
is usually inclosed by a delicate membrane, and which contains
chromatin and achromatin fibers and one or more nucleoli, and
(4) one or two centrosomes or attraction spheres.

Cell Division or Mitosis.—-The centrosome <livides into two
parts, which gradually separate, and each of which becomes the
center of a system of fine achromatin fibers radiating about it.
A spindle of achromatin fibers is also extended from one centro-
some to the other. At the same time the chromatin granules
scattered throughout the nucleus are arranged into a continu-
ous thread or skein of closely contorted filaments. The nuclear

1 Wilson, ‘‘ The Cell.”

384 THEORIES OF DEVELOPMENT

membrane generally disintegrates and the chromatin thread is
broken up into U-shaped fragments (chromosomes). These
U-shaped chromosomes are arranged as the equatorial plate
half-way between the centrosomes and across the axis of the
spindle. Either before or after the formation of the equatorial
plate the chromosomes split longitudinally, so that each part
contains an equal amount of the chromatin. The chromosomes
now move along the spindle (or its fibers contract), so that one-
half of each original chromosome is drawn to one centrosome
and the other half to the other centrosome. These chromo-
somes, with their apexes pointing toward the center, are now
arranged about their respective centrosomes. The protoplasm
of the general cell becomes constricted in the center, each group
of chromatin loops rearranges itself into a nucleus like that of
the mother cell, and an investing membrane becomes ap-
parent. A furrow appears on the surface of the protoplasm and
gradually deepens until the protoplasm is divided into two equal
segments, each containing its own nucleus and centrosome and
being a complete daughter-cell.

Maturation.—Metazoans usually reproduce by means of
fertilized eggs or ova. Egg cells vary in size from less than zt
to about yay inch in diameter. By this is meant the minute
germ cell without the enormous amount of nutritive material
which usually accompanies it.

Before the process of fertilization takes place (about the
time of the entrance of the spermatozoén, which, however,
takes no part in the process) the ovum undergoes a process of
maturation, in which one-half of the number of chromosomes is
thrown off. A spindle-shaped structure is formed from minute
fibers in the cytoplasm. The centrosomes, one at cach pole of
the spindle, seem to control its formation and activities. This
spindle draws from the egg nucleus a definite number of chro-
mosomes which are arranged across the center of the spindle,
which now moves endwise toward the surface of the egg. A
small protrusion is made, the spindle divides across the center,
and the first. polar cell, consisting of a nucleus with chromo-
somes and a smal] amount of cytoplasm, is formed and thrown
off. The remaining portion of the spindie disappears. The
other centrosome divides into two and forms another spindle,

SEGMENTATION 380

on which the chromosomes are again arranged as before, and
the second polar cell is formed. These polar cells disintegrate.
The nucleus of the ovum now contains only about half the
number of chromosomes present before the proccss of throwing
off the polar bodies. This remaining portion of the nucleus
retires from the circumference and is called the female pro-
nucleus, or macrogamete, which is ready for fertilization. The
spermatozoén previous to entering the ovum undergoes a
similar reduction of chromosomes, though the resulting cells
form sperms.

Fertilization The enveloping membrane of the ovum con-
tains one or more minute openings through which the sper-
matozo6n, or male germ cell, enters for the purpose of fertiliza-
tion. The spermatozo6én consists of a nucleus or extremely
minute head, a centrosome, and a flagellum or tail, which is
for the purpose of locomotion and disappears upon the entrance
of the spermatozo6n into the ovum. The nucleus, called the
male pronucleus or microgamete, enlarges, the centrosome
divides, and a mitotic figure is formed which moves toward the
female pronucleus, which moves toward the male pronucleus.
Finally, male and female nuclei meet in the midst of the spindle
formed about the male nucleus; thus the male and female
nuclei are united into one nucleus or zygote.

Segmentation.—This zygote or fertilized ovum now contains
the normal number of chromosomes or “hereditary threads’
for its species, one-half of which have been furnished by the
maternal cell and one-half by the paternal cell. When the
process of mitosis is completed, this zygote is divided into two
daughter-cells, each containing the same number of chromo-
somes, half of which have been derived from the sperm and half
from the ovum. Each of these daughter-cells subdivides into
two, and the resulting four, into eight cells, and so on, the num-
ber varying with different species. When there is little or no
yolk or nutritive material the whole egg divides equally; when
there is much yolk the division is unequal or partial.

Differentiation of Tissues.—From the ectoderm are produced
the outer portion of the skin and its outgrowths and the whole
nervous system; from the endoderm come the lining of the di-
gestive tract and the essential parts of the glands connected with

25

386 THEORIES OF DEVELOPMENT

it. The mesoderm gives rise to the bones and muscles, the cir-
culatory system, and the muscular walls of the alimentary tube.
All metazoans pass through these early stages of development,
and embryology teaches that from these simple beginnings the
most complex animal body is developed.

This sphere of cells is known as the morula or mulberry stage
(Fig. 5), and is succeeded by the blastula stage, in which the
cells are arranged in a circle about a cavity filled with watery
fluid. On account of inequalities, one portion of this sphere
becomes pitted, this pitting-in grows deeper until there is a
complete invagination of this portion, like the pushing in of one
side of a hollow rubber ball until the two sides touch. This is
called the gastrula stage, and occurs in all the main divisions
of the animal kingdom. (In many vertebrates delamination
supercedes or follows invagination, but this, perhaps, “is a
later development or, possibly, improvement upon gastrula-
tion.”') This gastrula stage is an open sac composed of two
layers of cells, the outer or ectoderm, and the inner or endoderm.
In most cases a third mass of cells, the mesoderm or middle
layer is formed, probably from the endoderm. The opening
of this sac-like body becomes the primitive mouth.

History and Theories of Evolution——Evolution is not a new
theory. Traces of such an idea are found in old Greek phil-
osophy. Empedocles (about 500 B. c.) believed that ‘plants first
sprang from the earth while the latter was in process of devel-
opment. After them came the animals, their parts having
first formed themselves independently and then been joined by
love.” After ceaseless trials, nature succeeded in producing
fit tribes for perpetuation. Osborn says this is the germ of the
“survival of the fittest.” Aristotle (884-322 8B. c.), though
believing in separate creation, taught vaguely that living beings
formed a gradual succession from the “less to the more perfect.”
Aristotle laid great stress upon the inductive method of study,
and he was so great an observer of animals as well as a collector
of the statements of others concerning them that he has been
called the founder of zodlogy. If only his principle—that ‘twe
must not accept a general principle from logic only, but must
prove its application to fact; for it is in facts that we must

1Romanes’ “ Darwin and After Darwin.”

HISTORY AND THEORIES OF EVOLUTION 387

seek general principles, and these must always accord with
facts” —had been remembered and applied by him and _ his
successors, science need not have progressed so slowly for so
many centuries.

The special creation theory interrupted scientific thought
and investigation for many centuries. Philosophy preceded
science in the line of evolutionary thought. Leibnitz, a German
philosopher (1646-1716), believed that “living beings form an
unbroken series from the simple to the complex, some steps in
the series having become extinct.’"' Buffon (1707-88) thought
that organisms could be modified by changes in food and envi-
ronment or by domestication, and that parts could be modified
by disuse. He was one of the first to attempt an explanation
of the geographic distribution of animals.

Erasmus Darwin (1781-1802), grandfather of Charles
Darwin, author of ‘‘The Origin of Species,”’ was a physician and
physiologist as well as a gardener and lover of plants. He
thought that the various plants and animals were descended
from “‘few ancestral forms or possibly from one and the same
kind of vital filaments.”” He emphasized function, saying that
“from their first rudiment or primordium to the termination
of their lives all animals undergo perpetual transformations;
which are in part produced by their own exertions in conse-
quence of their desires and aversions, of their pleasures and their
pains, or of irritations or of associations; and many of these
acquired forms or propensities are transmitted to their poster-
ity.”

Lamarck (1744-1829), although unappreciated in his own
day, scientists of the present day, whether agreeing with him or
not, admit to be one of the bravest of pioneers. Haeckel
says “to Lamarck will remain the immortal glory of having for
the first time established the theory of descent as an independ-
ent, scientific generalization of the first order as the foundation
of the whole of biology.””’ To quote Lamarck, ‘‘Nature in all]
her work proceeds gradually and could not produce all animals
at once. At first she formed only the simplest, and passed
from these on to the most complex.’ He gives four laws as
the summing up of his ideas: ;

1McFarland’s “ Biology.”

388 THEORIES OF DEVELOPMENT

(1) “Life by its inherent power tends continually to increase
the volume of every living body, and to extend the dimensions
of its parts up to a self-regulated limit.

(2) “The production of a new organ in an animal body re-
sults from the occurrence of some new need which continues to
make itself felt, and from a new movement which this need
originates and sustains.

(3) “The development of organs and their power of action
are constantly determined by the use of these organs.

(4) “All that has been acquired, begun, or changed in the
structure of individuals during the course of their life is pre-
served in reproduction and transmitted to the new individuals
which spring from those which have experienced the changes.”

But the man whose work is most completely identified with
organic evolution is Charles Darwin (1809-82), who after
spending many years in travel, observation, and investigation,
published in 1858 a paper of great scientific interest. At the
same time, by the arrangement of friends, Wallace, then in the
Malay Archipelago, published his paper, giving essentially the
same conclusions. In 1859 Darwin published his great work,
“The Origin of Species,” in which natural selection was more
fully elaborated.

All organisms vary. These variations may be due to envi-
ronmental changes or to excess of food, to the inherited effect of
use or disuse of parts, or to atavism, reverting to the character-
istics of a remote ancestor, or to reversion, a character or
structure found in more recent ancestors. Darwin emphasizes
the fluctuating or indefinite variations as of most use in natural
selection. Every plant or animal must struggle for existence
because of the vast number of other plants and animals and
because of conditions of environment, such as cold, heat, or
drouth. This struggle is threefold: (1) with its own species;
(2) with other species of plants or animals which may prey
upon it or its food, and (3) against unfavorable conditions of
climate or weather. Those which most frequently survive do
so because of certain individual characteristics which have made
them able to win in this struggle for existence, or, as Spencer
says, ‘‘the fittest survive.”” Now, according to Darwin, nature
takes advantage of these favorable variations possessed by the

HISTORY AND THEORIES OF EVOLUTION 389

survivors, and they are transmitted by heredity to their off-
spring, while those having less favorable adaptations do not
survive and, hence, are eliminated. Thus did Darwin think
that species came into existence—by a gradual improvement
of advantageous variations until the type was best adapted
to its surroundings. ‘I am convinced,” he said, ‘that natural
selection has been the main though not the exclusive means of
modification.”

One of the many objections offered against this theory is the
perpetuation and improvement of disadvantageous modifica-
tions, such as the beautiful colors and songs of birds and adap-
tations for fighting which render them conspicuous. Darwin
explained many of these cases by his theory of sexual selection.
Among the higher animals it is a fact of common observance
that in mating the members of either sex prefer the most at-
tractive individuals of the opposite sex. The successful rival
wins the mate, and, of course, it is his characteristics which are
transmitted and improved in succeeding generations. Adap-
tations for rivalry by battle among males are explained in the
same way.

Among the helpful contemporaries of Darwin several must be
mentioned. To Herbert Spencer (1820-1903), the philosopher
and author of ‘Principles of Biology,’ we owe the phrase,
‘the survival of the fittest.’”” Haeckel summed up the recapit-
ulation theory of Von Baer (published in 1828)—7. e., that the
embryonic phases of higher forms resemble or pass through the
corresponding embryonic stages of lower forms—in his funda-
mental law of biogenesis, that ontogeny recapitulates philogeny.
Huxley was the author of ‘“Man’s Place in Nature.”

Dr. August Weismann (born in 1834) is the foremost oppo-
nent of Lamarck as to transmission of acquired characters. He
led to the critical examination of reported cases, and he claims
that no case really shows the transmission of acquired char-
acters. He recognizes the chromatin as the hereditary sub-
stance or idioplasm, and calls the idioplasm of the germ cells
germ plasm. This germ plasm, he says, is “never formed de
novo, but it grows and increases ceaselessly ; it is handed on from
one generation to another like a long root creeping through the
earth, from which at regular distances shoots grow up and be-

390 THEORIES OF DEVELOPMENT

come plants, the individuals of the successive generations.”
He further states “that only those characters are transmissible
which have been controlled—i. e., produeed—by determinants of
the germ, and that consequently only those variations are
hereditary which result from the modification of several or many
determinants in the germ plasm, and not those which have
arisen subsequently in consequence of some influence exerted
upon the cells of the body. In other words, it follows from this
theory, that somatogenic or acquired characters cannot be trans-
mitted.

“This, however, does not imply that external influences are
incapable of producing hereditary variations; on the contrary,
they always give rise to such variations when they are capable
of modifying the determinants of the germ plasm. Climatic
influences, for example, may well produce permanent variations
by slowly causing gradually increasing variations to occur in
the determinants in the course of generations. The primary
cause of variation is always the effect of external influences.
When deviations only affect the soma they give rise to temporary
non-hereditary variations; but when they occur in the germ
plasm they are transmitted to the next generation and cause
corresponding hereditary variations in the body.”

The Mutation Theory.—De Vries is the chief exponent of the
mutation theory, though Bateson also emphasizes its import-
ance. This theory assumes that new species and varieties are
produced from existing forms by sudden leaps. These may
arise simultaneously and in groups, or separately and at more or
less widely distributed periods. This new theory does not
try to account for these sudden variations, but claims that
“when they occur it is a striking fact that the characters tend
to be transmitted.”’ When a mutation appears, it will survive
and leave descendants if it is adapted to its environment. Only
a comparatively small amount of evidence has been found to
support the zodlogic side of proof for this theory.

Orthogenesis is believed by many specialists, among whom
may be mentioned Eimer, Whitman, Tower, and Ruthven.
Development in a definite, predetermined direction, even if
this development is harmful to the race, is called orthogenesis.
“According to this theory, certain lines of development remain

HISTORY AND THEORIES OF EVOLUTION 391

stationary while others advance.” The explanation most
favored ‘‘ascribes the control of these modifications to the direct
effects of physiochemical factors on organisms.’’ Professor
Whitman says, ‘‘Natural selection, orthogenesis, and mutation
appear to present fundamental contradictions, but I believe
that each stands for truth, and reconciliation is not distant.”

Mendel’s law affirms that when mating takes place between
two animals unlike in some characteristic, the offspring will
often exhibit the characteristic of only one parent. This
characteristic is said to be dominant, while the character which
does not appear in the immediate descendants is said to be
recessive. The hybrids which result from the crossing of ani-
mals will produce a number of germ cells which bear only the
pure character of one parent and the same number which bear
only the pure character of the other parent.

From this law follows the occurrence in the next and succeed-
ing hybrid generations of a definite number of forms in definite
numerical proportions. Thus, when gray rabbits are crossed
with albino rabbits, all the immediate offspring are gray, while
in the next generation produced by the breeding together of
these gray hybrids there will occur in nearly every case three
gray young to one albino. This is explained in the following
way: the second generation is all gray because in the zygote, or
fertilized germ cell, the chromosomes, or hereditary units, which
bear the gray character are more potent in the color of the young
than are the chromosomes bearing the albino character. This
gray character is said to be dominant; the recessive albino char-
acters are not destroyed, but are carried over and give rise to
chromosomes of their own character, so that in the breeding
of two hybrids one albino germ cell from each of the two sexes
unite to produce one albino descendant. If one of the hybrid
dominants (gray) is mated with a recessive animal, half of the
young are hybrid dominants and half recessive. One who has
found out by experiment which are dominant and which are
recessive characters may produce several distinct types within
aspecies. If future experiments add support to this law, it will
then be explained how races suddenly spring into existence and
become established.

By collecting evidence and arranging it in the form of pedi-

392 THEORIES OF DEVELOPMENT

grees, it has been possible to demonstrate in man the existence
of several characters which show Mendelian inheritance.
Though most of the evidence has relation to abnormal or dis-
eased conditions, investigations are now being made concerning
pedigrecs of normal characters. One of the most easily ob-
served is the natural color of the eye. ‘To what extent eye
color may be valuable as a criterion of race it is at present im-
possible to say, but if it is ever to become so, it will only be
after a searching Mendelian analysis has disclosed the factors
upon which the numerous varieties depend.

“A discussion of eye color suggests reflections of another
kind. It is difficult to believe that the markedly different states
of pigmentation which occur in the same species are not as-
sociated with deep-seated chemical differences influencing the
character and bent of the individual. May not these differences
in pigmentation be coupled with and so become in some measure
a guide to mental and temperamental characteristics?’

1 Punnctt’s ‘ Mendelism.”’

Psycho
Zoi

~ Recent

Quater-
nary

‘apir, Peceary, Bison, Llama.

Equus. Megatherwm,' Mylodn.

SSS

Equus Beds.
Squus, Tapirna, Elephaa

Phohippus Beds.
Plwhippus, Mastodon, Bos, ete

Miohippus Beds. a

CENOZOIC.

Mesozoic.

PAaLE0z01c.

ss

ARCHZAN.

Muhippuas, Dieratherium, Thinohyua.
Oreodon Beds.

Edentates, Hyanodon, Hyracodon.
Brontotherium Beds.

Mesohippus, Menodua, Elotherium.

Ay
2
3
3

Diplacodon Beds.
Epviuppus, Amynodon.
Dinoceias Beds.

Tinoceras, Uintatherum, Limnohyus,
Orolippus, Helaletes, Colonoceras,
Coryphodon Beds.
Eohippus, Monkeys,

Serpents

Carpivores, Ungulates, Tillodonts, Rodenta,

Lignite Series.
Hydrasaurus, Dryptosaurus.

z
8
S
ry

Pteranodon Beds
Birds with Teeth, Hesperornis, Ichthyorn.
Pterodactyls, Plesiosaurs.

Mosusaurs,

Dakota Group.

Juras-
sic.

Atlantosaurus Beds.
Dinosaurs, Apatosaurus, Allosaurus, Nanvsaurus.
plosaurus

Turtles. Di-

Triassic

Connecticut River Beds. 4
First Mammals (Marsupials), (Dromatherium).
Dinosaur Foot-prints, Amphisaurus.

Crocodiles (Belodon).

Permian.

Carboniferous.

Coal Measures.
Firat Reptiles (7).

Sub-carboniferous.
Firet known Ampbibiane (Labyrintbodonts).

Devonian.

Corniferous.

Schoharie Grit.
First known Fishes.

Silurian.

Upper Silurian.

Lower Silurian.

Cam-

SSS

Archean.

SS

Primordial.

Huronian.

Laurentian.

No Vertebrates known.

Fia. 302.-Section of the earth’s crust, to illustrate vertebrate life in America.
(After Marsh.) (From Le Conte’s Geology, American Book Co., Publishers.)

393

GLOSSARY

Agamically. Without fertilization.

Altricial. Hatched in a helpless condition, being wholly dependent upon
the care of the parent.

Analogous. Similar in function.

Ankylose. To consolidate or grow two bones into one.

Anthropologist. One versed in the science of the structure and function
of the human body or the development of the human race.

Apodal. Having no feet.

Atrophy. The wasting away or degeneration of an organ.

Biramous. Consisting of two branches.

Callosities. Spots of hard and thickened skin.

Caviare. The roes of sturgeons, salted and prepared for food.

Commensalism. The association of two species of organisms, where one,
at least, is benefited and the other not perceptibly injured.

Crepuscular. Feeding in the dusk or before sunrise.

Degeneration. The substitution of a lower for a higher form of struc-
ture, the hereditary deterioration of type.

Diastema. An intervening space, especially between the teeth.

Dimorphism. ‘The condition of the appearance of the same species
under two dissimilar forms.’’—Darwin.

Distal. Away from the place of attachment to the body.

Diurnal. Active or feeding by day.

Diverticulum. A blind tube branching out of a longer one.

Estivate. To pass the summer in a state of torpor.

Gregarious. Many individuals of one species banding or herding together
for mutual protection.

Gular. Pertaining to the gula or throat.

Hermaphroditism. The possession of both male and female reproductive
organs by the same individual.

Heterocercal. Having an unequally divided tail or caudal fin.

Histolysis. Disintegration or dissolution of organic tissue.

Homocercal. Having the caudal fin symmetric as to its lobes or halves.

Homogeneous. Alike throughout, having parts of only one kind.

Homoiothermal. Having a uniform temperature unaffected by environ-
ment.

Homologous. Similar in structure or origin.

396 GLOSSARY

Irritability. That power or property by which an organism is able to
respond to stimuli.

Littoral. Pertaining to the shore.

Lophophore. A disk which surrounds the mouth and bears the tentacles.

Medusoids. Medusa-like structures.

Metabolism. The process by which food is built up into living tissues,
and living material broken up into simpler products in an organism or
cell.

Milt. The spermatic fluid of fishes.

Myrmecophilous. Living with ants, said of insects which inhabit the
formicaries or nests of ants.

Natural selection “implies that the individuals which are best fitted for
the complex and, in the course of ages, changing conditions to which
they are exposed generally survive and procreate their kind.’’-—Darwin.

Nocturnal. Feeding or becoming active in the night.

Omnivorous. Eating both animal and vegetable food, feeding indis-
criminately.

Ontogeny. The development of an individual organism from its in-
cipiency in the egg to the adult state.

Operculum. A lid-shaped structure closing the aperture of a tube or
shell.

Ovoviparous, Viviparous. Hatching the eggs within the parent body, or
bringing forth living young.

Parthenogenesis. Reproduction by supposedly unfertilized eggs.

Pendactyl. Having five digits.

Pentameral. Arranged in fives.

Philogeny. The study of the ancestry of organisms, or the history of
the race.

Placenta. The vascular membrane which connects the embryo with the
mother and supplies it with nutriment.

Poikilothermal. Having a body temperature varying with that of the
environment.

Polymorphism. The condition of having many forms.

Precocial. Able to run about when hatched.

Proximal. Near the place of attachment to the body.

Pseudopodium. Any protoplasmic protrusion from a unicellular organ-
ism.

Recognition Mark. Coloration of special parts by which the members of
one species may recognize their own kind, particularly beneficial in the
recognition of parents by the young.

Reversion. A return toward a recent ancestral type or character.

Rheotropism. The directive influence upon growth exerted by currents
of water or air.

GLOSSARY 397

Roe. The ova or spawn of fishes and amphibians, especially when still
inclosed in the ovarian membranes.

Rudimentary. In an early stage of development.

Sarcode. The gelatinous matcrial forming the bodies of sponges and other
low animal forms.

Somites. The segments of which an articulated body is composed.

Stomodeum. The primitive mouth and esophagus found in actinozoans
and in the embryos of annelids and arthropods.

Symbiosis. The living together of two species of animals or plants, inti-
mately and permanently, to their mutual advantage.

Syndactylous. Having the toes united for some distance, but without a
web.

Trochosphere. That larval form of various worms, mollusks, and mol-
luscoids which has a circlet of cilia.

Vestige. A structure of the past left behind; a degenerate organ or struc-
ture.

INDEX

ABOMASUM, 337
Acanthocephala, 44
Acanthopteri, 215
Acarina, 108
Acephala, 73
Achromatin, 383
Acrania, 194
Acrididz, 137, 138
Actinophrys, 9
Actinozoa, 26
Adaptation, wings of birds, 263
Agialitis vocifera, 291
Agalenide, 106
Aglossa, 73, 233
Agonoderus pallipes, 151
Alaudide, 301
Alces americanus, 342
Aletia argillacea, 167
Alligators, 2538, 254
Alluring colors of insects, 118
Alopias vulpes, 205
Alternation of generations, 8, 22
Alytes obstetricans, 226
Amblyopsidz, 214
Amblystoma punctatum, 232
Ameba terricola, 1
Ampelide, 304
Amphibia, 221
Amphioxus, 190, 194
Ampulle, 53
Anacanthini, 214
Andrenidex, 183
Anguillide, 213
Anis, 298
Annulata, 65
Anolis, 247
Anomia, 74
Anopheles, 4, 156

rossit, 157
Anosia plexippus, 118, 171
Anseres, 285
Ant-eater, 319, 321, 324

Antelopes, 345
Anthrenus scrophulariew, 153
Anthropoid apes, 375
Anthropoidea, 372, 373
Anthropopithecus erectus, 379
Antilocapra americana, 344
Ants, 174, 177
agricultural, 180
carpenter, 179
communism of, 179
corn-louse, 180
intelligence of, 180
mound-building, 179
slave-making, 179
Anura, 224, 228
Aphidide, 140
Aphides, 124
Aphids, 148
Apide, 188
Apis, 184
Apoda, 228
Aptera, 126
Apteria, 259
Arachnida, 103
Araneida, 104
Archeopteryz, 258, 369
Arctomys marmotta, 352
Ardea candidissima, 228
egretta, 288
Aristotle, 386
Armadillos, 324
Aromochelys odoratus, 253
Arthropoda, 89
classification of, 186
Arthrostraca, 102, 103
Artiodactyla, 332, 334
Ascaris lumbricoides, 43
nigrovenosa, 41
Ascidians, 192
Assimilation, 7
Asterias vulgaris, 54
Asteroidea, 54

399

400

Atavisin, 388
Ateles, 374
Attide, 10S
Auk, 281
Automatism, 7
Aves, 258

Bapirusa, 365

Badger, 360

Balenopteride sibbaldii, 328

Balanoglossus, 190, 191

Baltimore oriole, 302

Barnacles, 91

Bass, 215

Bateson, 390

Bats, 368, 371

Bdelloida, 47

Bears, 359

Beavers, 353

Bees, 174, 183

Beetles, carpet, 173
ground, 151
myrmecophilous, 153
tiger, 150
water, 152

Belostomide, 142

Beluga, 328

Bettongia, 323

Bivalva, 73

Blackbirds, 302

Blastostyles, 22

Blastula, 385

Blattide, 134

Blind fishes, 214

Blissus leucopterus, 142

Blow-flies, 155

Bombide, 184

Bombinator, 227

Bombus, 184

Bombylide, 161

Bos bonasus, 348
grunniens, 348
primogenius, 348
sivalensis, 350

Bot-flies, 156

Bothriocephalus latus, 38

Bovide, 345

Brachiopoda, 48

Bradypodidex, 324

Bradypus, 324

Branchcllion, 70

Branchipus, 90

Brine shrimp, 90

INDEX

Buffalo fishes, 212

Buffon, 387

Bufo lentiginosus, 234

Bufonide, 234

Butterflies, 162
cabbage, 173

distinguished from moths, 163
gossamer-winged, 171, 173

swallow-tailed, 172

CaciLips®, 229

Calamistrum, 107

Calamoichthys, 210

Calasoma scrutator, 151

Calcarea, 16

Callinectes sapidus, 101

Camelide, 337

Camels, 337

Camelus bactrianus, 338
dromedarius, 33%

Campodea staphylinus, 127
Camponolus peonunsylvanicus, 179

Canidex, 361
Canis lupus, 362
occidentalis, 362
Cankerworms, 165
Capra egagrus, 345
iber, 345
pyrenaica, 345
Carabidae, 150
Carapace, 90
Caribou, 340
Carinate, 265, 281
Carnivora, 356
aquatic, 365
terrestrial, 358

Carpocapsa pomonella, 164

Cassidide, 83
Cassowary, 278, 280
Castor canadensis, 352
Castoride, 352
Catarrhina, 375
Cat, domestic, 364
family, 35S
Catfish, 212
Cattle, 345
Caudata, 229
Caviare, 210
Cavities, hemal, 191
neural, 191
Cebidex, 373
Cebus, 375
Cecidomyiidx, 160

Cell, division of, 383
polar, 385
structure of, 385
theory, 382

Centipedes, 111

Centrosome, 383, 384

Cephalopoda, S84

Cephalothorax, 90

Ceratina dupla, 183

Ceratodus, 209

Cercarie, 36

Cercopithecidx, 375

Cercopithecine, 375

Certhiide, 305

Cervide, 339

Cervus canadensis, 340

Cestoda, 37

Cetacea, 312, 314, 315, 318, 326

Chetognatha, 44

Chetopoda, 65

Chamelion, 247

Chamois, 346

Chele, 95

Chelonia, 248

Chemotropism, 7

Chevrotain, 337

Chigoe, 162

Chilopoda, 111

Chimera monstrosa, 207

Chimpanzee, 377

Chinch-bug, 140, 142

Chiroptera, 368

Chlamydophorus, 325

Cholepus, 324

Chondrostei, 210

Chordata, 188

Chromis, 212

Chromosomes, 384

Chrysemys marginata, 253

Chylema, 383

Chylomycterus geometricus, 204

Cicada, 142

Cicadide, 142

Cicindelide, 150

Cilia, 5

Cirri, 91

Cirripedia, 91

Cistudo, 253

Civets, 365

Clitellum, 68

Clubionide, 106

Clytus erictus, 175

Cobweb-weavers, 107

Coccidex, 140, 146

26

INDEX 401

Coceincllide, 153
Coccyges, 297
Cockroaches, 134
Codfish, 214
Coelenterata, 17
Coleoptera, 148
Collembola, 127
Color, changes of, theories of, 361
Colubridx, 243
Columb, 292
Columba livia, 293
Commensalism, 14, 65, 100, 102
Communism of ants, 179
Condylura cristola, 367
Congo snake, 231
Conjugation, 8
Contractile vacuole, 2
Contractility, 8, 13
Coot, 289
Copepoda, 91
Coral, secretion of, 17

stony, 29
Cormorant, 285
Corn-ear worm, 167
Corvide, 301
Cosside, 164
Cotton-boll worm, 167
Cotton worm, 167
Cowbird, 302
Cowries, 82
Coyote, 363
Crabs, blue, 101

fiddler, 102

hermit, 100

oyster, 102

spider, 102
Crane, 289
Craniata, 195
Crayfish, 90, 95
Creepers, 305
Cribellum, 107
Crickets, 139
Crinoidea, 62
Crocodiles, 253
Crocodilia, 253
Crossopterygii, 210
Crotalide, 243
Crows, 301
Crustacea, 90
Cryptobranchus, 231

alleghentensis, 231

japonicus, 231
Ctenidia, 82
Cteniza, 106

402 INDEX

Ctenophora, 17 Drasside, 106
Cuckoos, 298 Duck-bill, 320
Culex, 156 Dugong, 325

fatigans, 157 Duplicidentata, 355
Culicids, 156 Dyticide, 152
Curled-thread weavers, 107
Cuttlefishes, 84
Cyanea, 17, 26 EaGues, 294
Cyclops, 91 Ear-shells, 82
Cyclostomata, 195 Earthworm, 65
Cycloturus, 324 Ecaudata, 233
Cynipide, 176 Ecdysis, 227
Cynocephalus, 375 Echidna, 316
Cynomys, 352 aculeata, 319
Cypreide, 82 Echinodermata, 50
Cypress, 90 Echinorhynchus, 44
Cysticercus, 38 Economic importance of annulates,
Cytoplasm, 383 70

of bats, 369
of birds, 305-309

DacTYLETHRA, 233 of camels, 33S
Darwin, Charles, 388 of caribou, 341

Erasmus, 387 of cats, 365
Dasypodide, 324 of ccelenterates, 32
Dasypus sexcinclus, 325 of crustaceans, 99
Dasyuride, 321 of deer, 343
Deer, 339 of fishes, 217-219
Delphinide elphincraptus, 32S of hawks, 295
Dendrobates tinctorius, 227 of hogs, 335
Dendrolagus, 322 of horses, 334
Dermophis, 229 of insectivores, 368
De Vries, 390 of insects, 125
Diapheromera femorata, 137 of mollusks, S7
Dictynide, 107 of nemathelminthes, 47
Didelphide, 321 of platyhelminthes, 40
Didelphys, 321 of protozoans, 9
Dimorphism of spiders, 106 of reindeer, 340

of trochelminthes, +47 of reptiles, 257
Dinophilea, 47 of rodents, 356
Dinosauria, 256 of sponges, 14
Diodon maculata, 204 of sturgeons, 210
Diplopoda, 112 of tapirs, 332
Dipneumones, 106 of whales, 329
Dipnoi, 208, 220 of yak, 349
Dipodide, 354 Ectoderm, 17
Diptera, 153 Ectoplasm, 2
Dispersal of hydra, 20 Edentata, 323

of starfish, 55 Eels, 213
Dodo, 293 Elapide, 243
Dolomedes, 108 Electrotropism, 7
Dolphins, 328 Elephant, 330
Dormice, 353 mammoth, 331
Dracunculus medinensis, 43 Elephantiasis, 157
Dragon-flies, 129 Elephas africanus, 331

Elephas indicus, 331
Elk, 340

Elytra, 149
Empedocles, 386
Emu, 280

Encysting, 3
Endoderm, 10, 17
Endoplasm, 2
Endopod, 90
Entomostraca, 90
Ephemerida, 127
Epilachna borealis, 153
Epomophorus, 371
Equide, 334
Erinaceus europeus, 366
Eristalis, 175
Eumemes fraternus, 181
Eumenide, 181
Euplectella, 16
Euspongia, 16
Evolution, 386
Exopod, 90
Exoskeleton, 114
Eye-color, 392

Fatconipm, 294
Felide, 358, 363
Felis caffra, 364
concolor, 364
leo, 363
maniculata, 364
onca, 364
pardus, 364
tigris, 364
uncia, 364
Feniseca taquinius, 173
Fertilization, 385
Fiber osoyoosensis, 352
Filiariasis, 157
Fins, pectoral, ventral, 199
Fish-moth, 127
Fission, 8
Fissipedia, 358
Flagellum, 4
Flat-worms, 34
Fleas, 161
Flesh-fly, 155
Flies, 154-156
Flounders, 215
Fly-catchers, 301
Formica difficilis, 179
exsectotdes, 179
Formicide, 179

INDEX 403

Foxes, 361

Frigate, 285

Fringillidee, 302

Frogs, 236

Funnel web weavers, 106

GALL-FLigs, 175, 176
Gall-gnats, 160
Galline, 291
Gallinago delicata, 291
Gallus bankivus, 292
Gammarus, 102
Gar-pike, 211.
Gasteropoda, S81
Gastrophilus equi, 156
Gastrotricha, 47
Gastrula, 386
Gavial, 254

Geese, 285
Gemmules, 12
Geomyide, 354
Geotropism, 7, 13
Gephyreza, 69

Germ plasm, 389
Gibbons, 376
Giraffes, 343
Giraffiide, 343
Glass-snake, 245

Glires, 350
Globigerina ooze, 9
Goats, 345
Gonionemus, 26
Gonium, 1

Gonotheca, 22
Gophers, 354
Gordius, 44
Gorgonacea, 31
Gorillas, 378
Grackles, 302
Grantia, 116
Graptolites, 32
Grebe, 28
Gregarina, 4
Guinea-worm, 43
Gull, 282
Gymnodonta, 216
Gymnophiona, 225, 228

Hemopsis vorax, 70
Hemosporidia, 4
Hair-worm, 44
Halictus, 183

404

Haliolida, 82
Hawks, 294

red-tailed, 295

sharp-shinned, 295
Hedgehogs, 366
Helicide, 83
Heliothis armigera, 167
Helix, 83
Hellbender, 231
Helmet-shells, 83
Hemiptera, 138, 140
Hepatic ceca, 192
Heredity, 388, 390
Hermaphroditism of cirripedia, 91

definition of, 19

of holothuroidea, 62

of hydra, 19

of leeches, 69

of mollusks, 73

of porifera, 11
Herodiones, 286
Heron, 287
Hessian fly, 160
FHeterodera schachtii, 41
Heterogeny, 40
Heteroptera, 141
Hippocampus, 204
Hippopotamide, 334
Hippotragus niger, 345
Hirudinea, 69
Hirugo sanguisuya, 70
Hirundinide, 304
Hog, 335
Holocephala, 207
Holostei, 210
Holothuroidea, 60
Homoptera, 141
Homo sapiens, 379
Honey bee, 184
Hooke, 382
Hook-worm, 43
Horned toad, 247
Hornets, 182
Horn-tails, 175
Horse, 334

fly, 156
House fly, 154
Humming birds, 300
Fynide, 358, 365
Hydra, 17

viridis, 21
Hydractinea, 24, 25
Hydroid, 21
Hydrotheca, 21

INDEX

Hydrozoa, 18

Hyla versicolor, 234
Hylide, 234
Hylobates, 376
Hylodes liniatus, 226
Hymenoptera, 174
Hypoderma lineata, 156
Hypostome, 18
Hyracoidea, 329
Hyrax, 329

Icerya purchasi, 153
Ichneumonide, 176
Ichthyophis, 229
Ichthyopterygia, 256
Iguana, 248
Incubation, 268
Infusoria, 5
Inquilines, 176, 184
Insecta, 112
Insectivora, 366
Intelligence of ants, 180
of birds, 273
Iphiclides ajax, 172
Irritability, 7, 8, 13
Isoptera, 131
Tulus, 112
Ixodes, 110

JACKALS, 362

Jays, 301

Jennings, on ectoplasm, 3
Jumping mice, 354

Kania, 118
IXungeroos, 322
Katy-dids, 139
Iilldeer, 291
Kingfishers, 297
Iinosternide, 253

Laprium, 133
Labrum, 133

' Lacertilia, 243

Lady-bugs, 153
Letilia coceidivera,
Lamarck, 387
Lamellibranchiata,
Lampyridx, 153
Lancelet, 190

164

wis |

ws

Land birds, 291
Larks, 301
Lasius brunneus, 180
Leibnitz, 387
Lemuridez, 372
Lemuroidea, 372
Leopard, 364
hunting, 365
Lepas, 92
Lepidoptera, 162
Lepidosiren, 209
Lepisma saccharina, 127
Lepomis cyanellus, 215
Leporide, 250, 255
Leptoplana, 34
Lepus, 355
americanus, 356
aquaticus, 355
campestris, 356
palustris, 355
sylvaticus, 355
Libellulide, 129
Life, Archean, 382
origin of, 382
Limacide, 83
Limicole, 290
Limnezus, 84
Limpets, 82
Limulus, 110
Linckia linckia, 56
Lion, 363
Lithobius, 111
Lithorina, 83
Liver-fluke, 36
Llama, 339
Lobster, 90, 99
Locustide, 138
Locusts, 137
seventeen-year, 143
Longipennes, 282
Loon, 281
Lophobranchii, 212, 216
Lophophore, 48
Loris, 372
Lutra, 359
Lyccenide, 173
Lycostidz, 108
Lymantriide, 168
Lynx, 364

Macaquss, 375
Macheira, 102
Mackerel, 215

INDEX

Macrochires, 300
Macronucleus, 5
Macropodide, 322
Macropus, 322, 323
Madreporic plate, 52
Malacostraca, 90, 92
Malpighian tubes, 120
Mammalia, 311

Man, 379

Manatee, 325
Mantide, 136
Mantids, praying, 136
Marine worms, 68
Marmosets, 373
Marmot, 352
Marsupialia, 320
Marten, 360

Maryland yellow-throat, 305

Mastigophora, 4
Maturation, 384
Maxilla, 133
Maxillary palpus, 133
May-flies, 127
Meduse, 22
Megachile acuta, 183
Megachiroptera, 370
Melanoplus atlantis, 138
femur-rubrum, 137
spretus, 137
Meleagrina, 77
Meles, 360
Melipona, 184
Mendel’s law, 391
Mephitis, 360
Mesoderm, 386
Mesoglea, 10, 17
Mesothorax, 133
Metabolism, 7
Metamorphosis, 26
Metathorax, 133
Metazoa, 10
Microchiroptera, 370, 371
Micronucleus, 5
Microtus, 353
Migration, 274
Millepora alicornis, 25
Millipeds, 112
Milt, 212

Mimicry of hymenoptera, 175

of insects, 119

of viceroy, 172
Mink, 360
Mitosis, 383
Mniotiltide, 304

405

406

Mole, 367

Australian, 322
Mollusca, 72
Molluscoida, 48
Molting of crayfish, 9S
Monarch butterfly, 172
Monitors, 248
Monkeys of America, 373

Old World, 375

orang-utan, 376

Saki, 374

spider, 374

squirrel, 374
Monobia quadridens, 181
Monotremata, 319
Moose, 342
Morula, 385
Mosquitoes, 156
Moths, 162

carpenter, 164

coccid-eating, 164

codling, 164

gypsy, 169

hawk, 170

meal, 164

owlet, 166

tussock, 168
Mud-eel, 229

Multiplication, sexual, asexual, 11

Muride, 352
Musca domestica, 154

Muscardinius avellanarius, 353

Muscidxe, 154
Mus decumanus, 352
minutus, 352
musculus, 352
Muskrat, 352
Mustelidx, 359
Mutation, 390
Mya arenaria, 80
Mydaus milictes, 360
Mygale, 106
Myogale moscata, 367
Myriapoda, 111
Myrmecophagidi, 324
jubala, 324
Myrmicidie, 180
Mytilus, 74

Nasauis, 375

Natica, 83

Natural selection, 388
Nauplius, 90

INDEX

Nautilus, 86
Nebalia, 93
Necrophorus, 150
Necturus, 223, 231
Nemathelminthes, 41
Nematocysts, 19
Nematoda, 41
Nematus ribesti, 175
Nemertinea, 39
Neotony, 232
Nephridia, 68, 201
Nereis, 69

Newts, 232
Nictitating membrane, 271
Night hawk, 300
Noctuide, 166
Non-ruminants, 334
Nototrema marsupiatum, 226
Nucleoli, 383
Nucleus, 2
Nudibranchs, 83
Nuthatches, 305

OcELut, 123
Ocneria dispar, 169
Octocoralla, 31
Octopus, 85
Odocotleus virginianus, 339
Odonata, 129
Odontoglosse, 286
(Estridee, 156
Oligocottus snyderi, 198
Omasum, 337
Ophidia, 239
Ophiopholis, 58
Ophiuroidea, 56
Orb weavers, 107
Orientation, 7
Ornithorynchus, 320
Orthogenesis, 390
Orthoptera, 132
Osculum, 10
Ostracoda, 90
Ostrea, 74

edulis, 77

virginiana, 77
Ostrich, 278, 279
Otlaria jubata, 365

ursina, 365
Otolith, 203
Otter, 359
Ova, 384

size of, 384

Ovibos moschatus, 348
Ox-warble larva, 156
Oyster, 74

drills, 83

Palemonetes vulgaris, 99
Paludicole, 289
Panther, 364
Papilionid, 172
Parameles, 321
Paramcecium, 5
Parasita, 141
Parasitism of birds, 276
of hymenoptera, 176
of insects, 124
of thyca, 56
Paride, 305
Parr, 212
Parthenogenesis, 124
Passeres, 300
Patagium, 258
Patellide, 82
Pecten trradians, 77
jacobeus, 77
maximus, 77
Pedicellaria, 54
Peduncle, 48
Pelecanus californicus, 285
erythrorhynchus, 285
fuscus, 285
Pelecypoda, 73
Pelican, 285
Penguin, 281
Pennatulacea, 31
Pepsis formosa, 181
Perch, 215
Perissodactyla, 332
Periwinkle, 83
Perlide, 128
Petrel, 284
Petrogale, 323
Phalangeridx, 322
Phalangidea, 104
Phalaropes, 291
Phaneroglossa, 234
Pharyngognathi, 212
Phasmide, 137
Phasmomantis carolina, 136
Philohela minor, 291
Phocide, 366
Pholas, 8
Phoronida, 48
Phototropism, 7

INDEX 407

Phrynosoma, 247
Phyllium, 118
Phyllocardia, 93
Phyllopoda, 90
Phylloxera, 145
Phylostoma hastatum, 371
Physa, 84
Physeter macrocephalus, 328
Physteride, 328
Pici, 298
Pieris, 173
Pill-bug, 90, 102
Pinnipedia, 365
Pinnotheres, 76
Pipa, 233
Pipe-fish, 217
Pisces, 196
Pitheca, 374
Planaria, 34
Planorbis, 84
Plasma, 383
Platyhelminthes, 34
Platypsylla castoris, 153
Platyrrhina, 373
Plecoptera, 128
Plectognathi, 216
Plover, 291
Pluteus, 57, 60
Pogonomyrmex, 180
Polychetz, 68
Polyergus refescens, 179
Polypterus, 210
Polyzoa, 48
Pond-snail, 83
Poneride, 180
Porcupines, 353
Porpoises, 328
Prairie-dog, 352
Prawn, 99
Primates, 372
Proboscidea, 372
Procamelus, 349
Procyonide, 358
Prong-horn, 344
Prostomium, 47
Proteide, 230
Proteus, 225, 231
Prothorax, 114
Protoplasm, 1
properties of, 7
Protopod, 90
Protopterus, 206, 209
Protovertebrates, 191

| Protozoa, 1

408 INDEX

Protozoa, malaria-producing, 4

Pseudobranchus striatus, 230

Pseudopodia, 2

Psithyrus, 184

Psittaci, 297

Pterosauria, 257

Pteryle, 259

Pulicide, 161

Pulmonata, 83

Puma, 364

Putorius fetidus, 360
rixosus, 361

Pygopodes, 281

Pyralis farinalis, 164

QUAIL, 292

Raccoon, 358
Radiolaria, 3
ooze, 9
Raiide, 206
Rail, 289
Rana catesbiana, 236
clamata, 236
Rangifer tarandus, 340
Raptores, 294
Rat fleas, 162
Ratitz, 265, 278
Recurvirostra americana, 291
Reindeer, 340
Remora, 210
Reptilia, 236
Resemblance, protective, of bats, 370
of birds, 270
of crayfishes, 99
of flat-worms, 34
of geometrids, 165
of insects, 115
of pipe-fish, 217
of sea-cucumbcr, 61
of sea-urchin, 58
of weasel, 361
special protective, kallima, 118
mantids, 136
variable protective, 118
Rivalry of birds, 276, 292
of seals, 366
Rock wallabies, 323
Rodentia, 350
Rotifera, 46
Round-worms, 41
Ruminants, 336

Saimiri, 374
Salamander, 231
maculosa, 227
Salamandride, 231
Salmon, 213
Salmonide, 213
Sand-stars, 57
Sand-worm, 69
San José scale, 148
Sarcode, 11
Sarcophaga sarracenie, 155
Sarcoptes scabet, 110
Sargassum, 198
Sauropterygia, 256
Saw-flies, 175
Seale bugs, 146
Scales, ctenoid, 198
cycloid, 198
ganoid, 197
placoid, 197
Scallop, 77
Scalops aquaticus machrinus, 367
Schleiden, 382
Schools of fishes, 212
Schwann, 382
Sciuropterus, 352
Sciurus, 352
Scolopendra, 111
Scombridex, 215
Scorpanoids, 204
Scorpionida, 103
Scorpions, 103
Sea-anemone, 27
Sea-cucumber, 61
Sea-horse, 217
Sca-mussels, S4
Sea-squirt, 192
Seals, 365, 366
Segmentation, 385
self-defense of amphibians, 226
of fishes, 204
of glass-snake, 246
of insects, 115
of snakes, 241
of turtles, 251
Sesia, 175
Sete, 67
Sexual selection, 386
Sheep, 345, 347
bot-fly, 156
Shrimp, 99
Niluride, 212
Simiide, 375, 376
Siphonaptera, 161

Sirenia, 312, 314, 325
Sirenide, 229
Stren lactertina, 229
Siricide, 175
Skunks, 360
Sloths, 324
Slugs, 83
Smolt, 212
Snails, 83
Snipes, 291
Song of birds, 277
Sorex palustris, 366
personatus, 366
Soricide, 366
Spermatozoén, 385
Sphargis coriacea, 252
Sphecina, 181
Sphendon punctatum, 238
Sphingide, 170
Sphynx moth, 170
Spider, crab, 108
ground, 106
jumping, 108
running, 108
Sponges, 10-16
Spongilla, 12
Spongin, 11
Spores, 4
Sporocyst, 36
Sporotrichum globuliferum, 142
Sporozoa, 4
Sporulation, 3
Squamata, 239
Squid, 84, 85
Squirrels, 351
flying, 352
Starfish, 354
Steganopodes, 284
Stegocephala, 228
Stegomyia, 4
fasciata, 157
Stickleback fish, 216
Stilt, 291
Stimulus, 7
Stomodeum, beginning of, 26
Stone flies, 128
Stork, 287
Struggle for existence, 388
“ Survival of the fittest,” 388
Swallow-tailed butterflies, 172
tiger, 172
zebra, 172
Swallows, 304
Swan, 285

INDEX

Swift, 247, 300

Sword-fish, 205, 216

Symbiosis, definition of, 4
Hydra viridis and alge, 21
hydractinea and crab, 25
pinnotheres, 76
sponges and crab, 14

Syngamus trachealis, 43

Syrinx, 267

Syrphidez, 161

Syrphus flies, 161

TABANIDA, 156
Tenia echinococcus, 39

saginata, 38

solium, 37
Tamandua, 324
Tamaus striatus, 352
Tanagers, 304
Tapeworm, 37
Tapirs, 32
Tasmanian marsupials, 321
Teide, 245
Teleostei, 211
Teleostomi, 209
Teredo, 81
Termites, 131
Termitophily, 132
Tern, 282, 283
Terrapins, 252

mud, 253
Tessera, 26
Testudinide, 253
Tetrapneumones, 106
Thalessa, 176, 177
Thallassophryne, 204
Theridiidz, 107
Thermorpha, 256
Thermotropism, 7
Thigmotropism, 7
Thomisidx, 108
Thrashers, 305
Thrushes, 305
Thysanura, 126
Ticks, 110
Tiger, 364
Tinodera sinensis, 136
Tissues, differentiation of, 386
Tolypeutes, 325
Tortoises, 253
Tragulide, 337
Tree-frogs, 234
Trematoda, 35, 77

409

410 INDEX

Tremex columba, 175, 176
Trichechide, 366
Trichinella spiralis, 41
Trichinosis, 43
Tridacna gigas, 80
Tritonide, 83
Tritons, 232
Trochelminthes, 46
Trochosphere, 68
Troglodytidx, 305
Trogon, 298
Tube-weavers, 106
Tubinares, 283
Tunicata, 192
Turbellaria, 34
Turdide, 305
Turtles, box, 253

sea, 252

soft-shelled, 252

tortoise-shelled, 252
Tylenchus tritici, 41
Tympanic membrane of insects, 123
Typhionectes, 229
Typhlomolge rathbuni, 231
Typhlosole, 66
Tyrannide, 301

ULoporip#, 107
Ungulata, 329
Urochorda, 192
Urodela, 229
Urosalpinx cinerea, 83
Ursidx, 359

VACUOLE, 3
Vampires, 371

Varanus, 248
Vertebrata, 195
Vespa, 182
Vespertilionide, 371
Viceroy, 172
Viverride, 365
Vorticella, 7
Vulpes, 361

WALKING-STICKS, 137
Wallace, 388
Warblers, 304, 305
Warning colors, 118
Water birds, 281

bugs, 142
Waxwings, 304
Weasel, 360, 361
Weismann, 389
Whales, 326, 328
Whip-poor-will, 300
Whitman, 390, 391
Wild turkey, 292
Wolf, 362
Wombats, 322
Wrens, 305

XIPHOSURA, 110

YELLOW-FEVER mosquito, 157
Yellow-jackets, 182

ZYGOTE, 385

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perature, the influence of protein food, the specific dynamic action
of food-stuffs, the influence of fat and carbohydrate ingestion and of
mechanical work render the work unusually valuable. It will prove
extremely helpful to students of animal dietetics and of metabolism
generally. ,

Dr. A. P. Brubaker, Jefferson Medical College: “It is undoubtedly the
best presentation of the subject in English. The work is indispensable.”

Howell’s Physiology

Physiology. By Wiri1am H. Howat, M.D., Ph. D., Professor
of Physiology, Johns Hopkins University. Octavo of 1020 pages,
illustrated. Cloth, $4.00 net. Fifth Edition.

Dr. Howell’s work on human physiology has been aptly termed a
“storehouse of physiologic fact and scientific theory.” You will at
once be impressed with the fact that you are in touch with an expe-
rienced teacher and investigator.

Prof. G. H. Caldwell, University of North Dakota: “Of all the text-
books on physiology which I have examined, Howell’s is the best.”

Bergey’s lnlygiene

Hygiene. By D. H. Bercry, M.D., Assistant Professor of Bac-
teriology, University of Pennsylvania, Octavo of 530 pages, illus-
trated. Cloth, $3.00 net. Fourth Edition.

Dr. Bergey gives first place to ventilation, water-supply, sewage, indus-
trial and school hygiene, etc. His long experience in teaching this sub-
ject has made him familiar with teaching needs.

J.N. Hurty, M. D., Indiana University: “It is one of the best books
with which I am acquainted.”

8 Saunders’ College Text-Books

Morrow’s Care of Imjured

Immediate Care of the Injured. By Avpery S. Morrow, M.D.,
Adjunct Professor of Surgery, New York Polyclinic. Octavo of
360 pages, 242 illustrations. Cloth, $2.50 net. Second Edition.

Dr. Morrow’s book tells you just what to do in any emergency, and it
is illustrated in such a practical way taat the idea is caught at once.
There are chapters on bandaging, practical remedies, first-aid outfit,
hypodermic injections, antiseptics and disinfectants, accidents and
emergencies, hemorrhages, inflammation, contusions and wounds, burns
and scalds, the injurious effects of cold, fractures and dislocations,
sprains, removal of foreign bodies from the eye, ear, nose, etc., poisons,
and their antidotes. There is no book better adapted to first-aid class
work.

Health: “Here is a book that should find a place in every workshop
and factory and should be made a text-book in our schools.”

American Illustrated Dictionary

American [lustrated Medical Dictionary. By W.A,NeEwMAN
Dorranp, M. D., Member of Committee on Nomenclature and
Classification of Diseases, American Medical Association. Octavo
of rzo7 pages, with 323 illustrations, tr9 in colors. Flexible
leather, $4.50 net ; thumb indexed, $5.00 net. Seventh Edition

If you want an unabridged medical dictionary, this is the one you
want. It is down to the minute; its definitions are concise, yet accu-
rate and clear; it is extremely easy to consult; it defines all the newest
terms in medicine and the allied subjects; it is profusely illustrated.
This new edition alone defines over 5000 new terms not defined in any
other medical dictionary—bar none. There is no other medical dic-
tionary that will meet your needs as well as The American Illustrated.
Why not then get the best ?

John B. Murphy, M.D., Northwestern University: ‘It is unquestion-
ably the best lexicon on medical topics in the English language, and,
with all that, it is so compact for ready reference.”

DESCRIPTIVE CIRCULARS OF ALL BOOKS SENT FREE

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