But it is well to remember that man’s structure is riddled with evidences

that he passed from an ancestral, quadrupedal condition, through the

semi-erect to his present upright posture, slowly and laboriously. His

erect attitude, geologically speaking, is a very recent accomplishment,

and his anatomy, therefore, reveals many imperfect adaptations to his

newly acquired posture. These imperfect adaptations are the sources

of many grave diseases in mankind. It would require too technical a

knowledge of anatomy to explain these imperfect adaptations, and I will

therefore simply mention _rupture_ and _uterine displacements_ as due to

imperfect adaptations to the upright attitude.

The common origin of man and the ape accounts for many interesting

and otherwise inexplicable facts in anatomy. There is, for instance,

a muscle that is normally present in the orang-outang known as the

Opponens Hallucis. This muscle enables the orang to oppose his big toe

to the other toes, just as we can oppose our thumb to the other fingers

of our hand. This muscle is absent from the foot of man ordinarily. But

occasionally it is found in man, in the dissecting-room, as a rarity—as

an anomaly. The question naturally arises, why should this muscle be

present normally in the orang and absent normally in man, occurring in

the latter only as an abnormality? The theory of evolution gives the only

rational answer. The man-like, ape-like generalized ancestors of man and

the orang possessed this muscle, which was useful to them in grasping

the branches of the trees among which they lived. These ancestors used

the feet and hands alike for purposes of grasping (prehension) and

locomotion. But those descendants that evolved more and more man-ward

used the feet more for purposes of locomotion and less for grasping,

while they used the hands more for grasping and less for locomotion,

until, finally, man was created—a creature that uses his feet exclusively

for locomotion, and the hands entirely for grasping. Through disuse,

therefore, the _opponens hallucis_ gradually disappeared in man; so that

now it occurs only as a rare abnormality. The hereditary units that make

this muscle still lie dormant in most men are usually so weak, through

disuse, that they do not develop. Some unusual stimulus occasionally

causes the latent hereditary units to develop and makes it appear in man.

The same is the case with many other muscles and structures that are

normal in the modern anthropoid apes, and only occur as rarities in man.

The appearance of those muscles in man are instances of _atavism_, i. e.,

reversions to conditions that were normal in the ancestors of man and the

apes, as they are still normal in the latter.

USELESS SCAFFOLDING LEFT IN THE BODY.

Man, in his post-natal growth, as well as during his embryological

development, exhibits reminiscences of his animal ancestry. In the

structure and movement of the new-born babe, as well as in the adult

frame, we find continuous witnesses to the ancient animal strain.

On the theory that men in bygone ages were closely allied to simian

creatures in habit as well as structure; that they led an arboreal life;

and that, like the baby-monkeys to-day, the baby-men of other ages clung

to their mothers as they climbed among the trees, Dr. Louis Robinson

predicted that a =baby’s power for grasping= would likely be found to

equal that of a young monkey which had reached a corresponding period

of growth. He tested a large number of new-born infants in reference to

this power by extending his finger or a cane, to imitate the branch of

a tree, and observed how long they would hang there without any other

support (Plate XI). He made experiments on about sixty children under

a month old. About thirty of the children experimented upon were not

over an hour old. Dr. Robinson states that each of the infants, with two

exceptions, was able to hang to the finger or cane by its hands, like

an acrobat from a horizontal bar, and sustain the whole weight of its

body for at least ten seconds. Twelve of the infants, less than an hour

old, held on for half a minute before the grasp relaxed; while four of

this age held on for one minute. Over fifty of the infants when four

days old could continue the grip for half a minute. Three weeks after

birth the faculty for holding on reached its maximum, for at this age

several succeeded in hanging on for a minute and a half; two held on for

over two minutes; and one infant held on over two minutes and a half.

One infant that was less than an hour old hung by both hands to Dr.

Robinson’s finger for ten seconds, and then deliberately let go with his

right hand, as if to seek a better hold, and continued his grasp with the

left hand only, for five seconds longer. In none of these experiments

did the limbs of the infants hang down in the attitude of the erect

position, but the thighs were invariably in the baby-monkey attitude,

at right angles to the body. The doctor says that this attitude and

the disproportionately large development of the arms compared with the

legs give the photographs of the infants a striking resemblance to a

well-known picture of the celebrated chimpanzee, Sally, at the Zoölogical

Garden in London. In these experiments the infants very seldom gave any

sign of distress, and uttered no cry until the grasp began to give way.

The fact that the flexor muscles of the forearm of a new-born infant show

such remarkable strength while the other parts of the muscular system

are so conspicuously weak and flaccid,—that they are able to perform a

feat of muscular strength that will tax the powers of many a healthy

adult,—can be explained only on the theory of inherited instinct from

simian ancestors that lived in trees. This instinct is no longer useful

to an infant. It is a vestigial instinct, a useless scaffolding in its

life history.

[Illustration: PLATE XI.—Illustrating the grasping power of infants. Two

infants, ten and thirteen days old, respectively, supporting their weight

by the hands only (vestigial instinct.) Reproduced from a photograph

taken by Dr. Louis Robinson. By courtesy of the Open Court Publishing

Company.]

=Club-foot.= There is an ordinary case of malformation in the foot of a

child known as club-foot. The most common kind of this deformity is that

where the sole is turned inwards and upwards and the heel is raised.

Before birth all children pass through this condition as a perfectly

normal and natural one, and only gradually outgrow it (evolve beyond it).

But some children fail to evolve beyond this condition and have club-feet

throughout life, unless relieved by the surgeon. It is a very instructive

fact that this particular form of club-foot is the normal condition

of the adult gorilla and orang-outang. The foot of every child passes

through this gorilla phase, and if it does not develop beyond this phase

it retains the simian characters, and we call it an abnormality. In this

abnormality the anatomist finds that those bones that enter into the

formation of the ankle joint have the pronounced anatomical characters of

the adult orang-outang.

=Ribs.= Adult man possesses twelve pairs of ribs. The chimpanzee and

gorilla possess fourteen pairs. An older comparative anatomy predicted

that in an early embryonic condition man would be found to possess

thirteen or fourteen pairs. The prophecy has been verified.

=Hair.= The apes have hair over the entire body. At the sixth month

of the embryonic development the human fœtus is thickly covered with

a somewhat long, dark hair over all the body, except those parts that

are uncovered in the apes, viz.: the palms of the hands and the soles

of the feet. This covering of hair is called lanugo. Since it covers

all the body except the points noted, it extends, of course, all over

the ears, face and forehead. It is usually shed before birth. It is a

simian characteristic, and sometimes fails to disappear, but persists

and develops greatly. Therefore there are occasionally found such men

(“dog-faced men”) as the Russian Jeftichjeff. The Ainos of one of the

Japanese Islands also possess this extreme hairiness.

=Vermiform Appendix.= There are a number of vestigial structures in man

that are not only useless but even a menace to life. The most striking

of the vestigial structures that come under this category is a portion

of man’s large intestine which is called the Appendix Vermiformis. This

useless structure is a veritable death trap. In some animals, such as the

herbivorous ones, the appendix is very large, sometimes longer than the

body itself, and is of great use in digestion. But in man it has shrunken

to a small rudiment varying from two to six inches in length, which is

very liable to a grave form of disease that frequently causes death

unless timely treated by the surgeon. In the early embryo the appendix is

equal in caliber to the rest of the bowel, but at a certain date ceases

to grow _pari passu_ with it. At birth it has become a small rudiment of

the large intestine. In the new-born infant the appendix is often of the

same size as it is in the adult. This precocity of an organ is always an

indication that it was of great importance to the ancestors of the human

species.

=Tail.= Man, like the anthropoid apes, has no external tail; but, exactly

like them, he has a rudimentary one concealed beneath the skin. The

embryos of man and the ape at an early stage of growth possess a very

conspicuous tail, which is even longer than the limbs. In the embryo

of man even the muscles for wagging the tail are still found. In the

adult man these muscles are represented, normally, by bands of fibrous

tissue. In the dissecting-room one occasionally finds these muscles well

developed in the adult man. Man and the anthropoid apes have descended

from more primitive simian ancestors that possessed tails.

=Hearing.= Prominent among vestigial structures, though less easy for

beginners to understand, are those that point to piscine ancestors and

which, therefore, smack of the sea. Embryology points indubitably to the

fact that the ancient, geologic progenitors of man once lived a marine

life. In the history of the globe there was a time when all the animals

lived in the sea. Land animals appeared as later creations. Man, in

evolving from the primitive protozoan, passed through a marine-worm phase

and finally, through the ages, attained to the fish stage. The chief

characteristic of a fish is its apparatus for breathing the air dissolved

in the water. This apparatus consists of gills—strong bars with delicate,

highly vascular, fringe-like curtains hung on them, and through which the

blood is continually circulating. The circulating blood throws out its

impure gases and takes in from the water the pure air, thus breathing.

These bars or arches are five or seven in number in many fishes. Slits

extend from the surface of the fish between the bars to the throat, so

that the water which the fish takes into its mouth is forced out between

the bars, thus bathing the delicate curtains on them by which air is

breathed from the water. Sometimes the slits between the bars are open

and unprotected, as in the sharks; but in the modern fishes (teleosts)

they are protected by a lid (operculum). If these slits did not exist in

the neck all fishes would quickly perish. They are of so great use to

the fish that Natural Selection has taken exceptional care in perfecting

their mechanism.

It is one of the most interesting facts in evolution that these slits

in the fish’s neck are still represented in the neck of man. One of the

most prominent features in every mammalian embryo is the presence of four

clefts of the old gill-slits. So persistent are these characters that

children are occasionally born with persistent fissures leading to the

throat, so that milk, when swallowed, will come out on the neck through

an opening. Thus we have a persistent piscine characteristic as an

abnormality in the child.

When the fish-like ancestors of man left the water the elaborate

breathing apparatus was no longer needed for respiration. Nature, in

creating new adaptations for the land animal, did not discard the

elaborate gill apparatus that had been evolved through the ages;

but utilized this old apparatus for the new adaptations. Nature is

exceedingly economical and does not discard old organs when they can be

molded for new functions.

In the course of ages, through minute gradations, the first gill-slit and

portions of its adjacent bars were molded for purposes of hearing. In

man there are two passages leading to the drum or middle ear; one is the

external auditory canal (the opening which is seen in what is popularly

called the ear), and the other is a canal leading from the throat to the

middle ear. In the adult these two channels are partitioned off from

each other by the membrane of the drum. These canals are the counterpart

or homologues of the spiracle associated in the shark with the first

gill-slit. The external ear is developed by the coalescence of six

rounded tubercles appearing in the bars or branchial arches that surround

the first gill-slit. In the course of ages the remaining gill-bars

(branchial arches) were also modified for special uses.

In relation with the external ear of man are found rudimentary muscles

that are no longer useful and ordinarily are not under the control of

the will. These muscles are the exact counterparts of well developed

functional muscles found in great numbers of the lower animals. They are

present in man as vestigial structures, because he is descended from

animals in whom these muscles were well developed and functional.

The anatomy of man reveals so many additional vestigial structures

that we may look upon him as a museum of obsolete anatomies; he is

an old curiosity shop containing many discarded tools, many outgrown

and aborted organs. The lower animals as well as man contain so many

useless (vestigial) structures among their useful organs, and they are

so significant of a former state of things in which they were useful,

that anatomists are willing to stake the theory of evolution upon their

presence alone. Evolution explains a multitude of other facts about man

that are inexplicable on any other theory.

[Illustration: FIG. 19. Brain of Fish (Bluefish). A, dorsal view; B, side

view; of, olfactory lobe; cr, cerebrum; ol, optic lobes; cb, cerebellum;

m, medulla; th, thalami.]

In addition to pointing out the possible track along which man has

evolved from a primitive protozoan it would be interesting as well as

exceedingly instructive to trace the development of each structure and

organ in his body. But the subject is a vast one, and cannot be presented

here even in briefest outline. Yet it will be very valuable to trace the

unfolding of one organ, and that the highest, as a sample of what occurs

with every part of the body. I refer to the _development of the brain_.

THE DEVELOPMENT OF THE BRAIN IN PHYLOGENY AND ONTOGENY.

Fig. 19 represents the brain of an average bony fish. It consists of

six swellings in a line, one before the other. Beginning from the

end towards the spinal cord, they are designated as follows, viz.: a

single median lobe, the medulla (Metencephalon), m; then in front of

this is another single median lobe, the cerebellum (Epencephalon),

cb; then the optic lobes (Mesencephalon), right and left, ol; then

the thalami (Thalamencephalon), which are small and hidden from

view by the encroachment of the two adjacent segments; then the

cerebrum (Prosencephalon), cr; then, finally, the olfactory lobes

(Rhinencephalon), of. In this fish the largest of the segments are the

optic lobes, ol.

[Illustration: FIG. 20.—Brain of Reptile (Turtle). A, dorsal view; B,

side view; of, olfactory lobe; cr, cerebrum; th, thalami; ol, optic

lobes; cb, cerebellum; m, medulla.]

The reptile’s brain (Fig. 20) shows similar parts with the same serial

arrangement. The reptile is a higher creature, a more intelligent

animal, than the fish; and in consonance with this fact the cerebrum, cr,

is the larger and more dominant part of the brain instead of the optic

lobes, ol.

[Illustration: FIG. 21.—Brain of Marsupial (Opossum). A, side view; B,

dorsal view; of, olfactory lobes; cr, cerebrum; ol, optic lobes; cb,

cerebellum; m, medulla. Thalami concealed from view by the backwardly

extended cerebrum; also the optic lobes are partially covered by the

cerebrum.]

[Illustration: FIG. 22.—Brain of Lemur (Lemur nigrifrons). A, dorsal

view; B, side view; cr, cerebrum; cb, cerebellum; m, medulla.]

In the marsupial (Fig. 21), a more intelligent animal still, the

cerebrum, cr, has grown so large that it extends backwards and partially

covers the optic lobes. It is to be observed that in the marsupial the

cerebellum, cb (like the cerebrum, cr), has evolved to a higher phase. It

consists of a median lobe, cb, which is larger than the median cerebellum

of the lower creatures mentioned, and of two lateral lobes, one on either

side, which have been acquired in the course of evolution. The median

lobe, the homologue of the single, median cerebellum of lower animals,

is larger than the lateral ones. The cerebellum of the marsupial has its

surface increased by fissures, while that of the fish and reptile is

smooth. The fissured cerebellum is a higher evolution than the smooth

ones. In the groups of animals referred to so far the cerebrum is smooth

and the olfactory lobes are still in front, though much encroached upon

in the marsupial by the enlarging cerebrum. In those animals still

higher in the scale of life, such as the prosimiæ (Lemurs), the cerebrum

has reached yet larger proportions and complexity, and has grown still

farther backwards towards the medulla, so that it hides from view a

considerable portion of the cerebellum (Fig. 22); it has also grown

forward, thus concealing largely the olfactory lobes. The cerebrum is

no longer smooth, but has a number of simple fissures and convolutions

(the higher animals have numerous complex fissures and convolutions). The

lateral lobes of the cerebellum have increased relatively more than the

central lobe, and the whole organ has advanced in complexity of fissures.

In the higher simiæ (monkeys and apes) the cerebrum has grown so far

backwards as to almost completely cover the cerebellum and medulla,

and its convolutions have become much more numerous and complex. The

cerebellum has also grown greatly, and its lateral lobes are now larger

and more complex than the central lobe.

[Illustration: PLATE XII.—Brain of man: dorsal and side views. The

cerebrum has grown so far backwards and forwards as completely to hide

the other segments of the brain when looked at from the dorsal surface.

From Carus’s “The Soul of Man.” By courtesy of The Open Court Publishing

Company.]

Finally, in man (Plate XII), the whole brain has grown so enormously that

it is three times larger than the brain of the highest simian creature.

The cerebrum, especially, has increased enormously in size. It has grown

not only backwards (overlapping cerebellum), upwards, and downwards

on the sides, it has grown so far forwards as not only to cover the

olfactory lobes, but also to project far beyond them. The cerebellum has

also increased in size and complexity, especially the lateral lobes. The

ideal vertical section (Fig. 23) shows diagrammatically in one figure all

these stages in the evolution of the human brain through the geologic

ages.

[Illustration: FIG. 23.—Ideal, vertical and sagital section, representing

the ontogeny and phylogeny of the human brain. of, olfactory lobe; crf,

cerebrum of fish; ol, optic lobes of fish; cbf, cerebellum of fish; m,

medulla of fish; cbr, cerebellum of reptile; cbo, cerebellum of opossum;

cbl, cerebellum of lemur; cbm, cerebellum of man; cr, cerebrum. Cerebrum

convoluted in lemur; much more convoluted in man. Cerebellum convoluted

from opossum upwards; mm, medulla of man.

Modified from Le Conte.]

It is a very interesting and instructive fact that in the development of

the human brain from the fertilized ovum these same stages, which are

permanent conditions in the zoölogical (taxonomic) series, are passed

through by it as transient stages.

One of the earliest conditions of the human brain is that in which it

presents three swellings in a serial arrangement. They are known from

behind, forwards as hindbrain, midbrain, and forebrain. For our purposes

it is sufficiently accurate to say that the =fœtal brain=, in developing

from this early condition to a later and higher condition, differentiates

the hindbrain into the _medulla_ (Fig. 24, m) and the _cerebellum_

(cb); the midbrain becomes the _optic lobes_ (ol); and the forebrain

differentiates into the _thalami_ (th) and the _cerebrum_ (cr). A little

later the cerebrum buds forth the olfactory lobes (of), so that the human

brain will consist of six fundamental segments,—one behind the other.

This is the _fish stage_ in the growth of the human brain. (Compare Fig.

24 with Fig. 19.)

[Illustration: FIG. 24.—Diagrammatic representation of the brain of

a human fœtus of the third week. Representing the fish-phase in the

ontogeny of the human brain. Side view. cr, cerebrum; th, thalamus; ol,

optic lobes; cb, cerebellum; m, medulla. The olfactory lobes at this

stage are very small and are not shown.

FIG. 25.—Dorsal view of the brain of a human fœtus of about seven weeks.

Representing the reptilian phase in the ontogeny of the human brain. cr,

cerebrum; th, thalami; ol, optic lobes; cb, cerebellum; m, medulla.

FIG. 26.—Side view of the brain of a human fœtus of about three months.

Representing the marsupial phase in the ontogeny of the human brain.

cr, cerebrum; ol, optic lobes; cb, cerebellum; m, medulla. The thalami

are completely, and the optic lobes partially, covered by the greatly

enlarged cerebrum.]

As development proceeds the most conspicuous growth of the brain is

observed in connection with the cerebrum and cerebellum. The cerebrum

particularly grows relatively and actually larger and larger, but does

not yet cover any portion of the optic lobes. This is the _reptile

stage_, represented in Fig. 25. The cerebrum, continuing to grow, finally

covers the front portion of the optic lobes. This is the _marsupial

stage_, and is shown in Figs. 26 and 27. Growing further, it soon covers

a greater or less portion of the cerebellum. These are the prosimian

(Lemur) and simian stages. Finally it grows so far backward as to

completely cover the cerebellum, and so far forward as to project much

beyond the olfactory lobes. This is the human stage (Plate XII).

[Illustration: FIG. 27.—Dorsal view of the brain (and spinal cord) of a

human fœtus of about three months. Representing the marsupial phase of

development. cr, cerebrum; ol, optic lobes; cb, cerebellum; m, medulla;

bs, brachial enlargement of the spinal cord; ls, lumbar enlargement. The

thalami are entirely covered and hidden from view by the cerebrum.]

In the study of the phylogeny of the brain we found that the cerebrum

in fish, reptile, and lower marsupial is smooth. In the primitive

primates (Lemuroidea) it is convoluted; in the simiidæ it is still more

convoluted, while in man it reaches the climax of complexity in the

size, number, and sinuosity of its convolutions. The object of these

convolutions is to increase the surface of the cortex of the brain,

the cortex being the seat of psychic phenomena. Other things being

equal, the greater the amount of cortex the greater is the intelligence.

During its embryonic development the human cerebrum passes also through

the stage of smoothness to a convoluted condition; then through stages

of increasing complexity of convolutions. Simultaneously with this

advance of cerebral organization, there is an unfolding of increasing

intelligence.

The cerebellum presides over the co-ordination of the muscular movements

of the body. It also, like the cerebrum, passes through the fish,

reptile, marsupial, lemur, and simian phases. At first it consists only

of the median lobe; then the lateral lobes appear, at first small in

size, but getting larger and larger until they greatly surpass in bulk

the more primitive median portion. At first the cerebellum is smooth,

but as it develops, its fissures become greater and greater, thus

increasing its cortex, which presides over the muscular movements. With

the developing cerebellum are associated increasing powers of muscular

co-ordination; increasing delicacy and complexity of muscular movements.

Thus the ontogeny of the brain recapitulates its phylogeny.

THE BRAIN AND PSYCHIC PHENOMENA.

The bearing of the theory of evolution on ideas of creation, design, and

kindred subjects may briefly be referred to in connection with our views

about the relation of psychic phenomena to the brain.

The study of the human brain in its anatomical, physiological and

psychological aspects has brought great thinkers, in all ages, into

the presence of phenomena that still baffle some of the most subtle

philosophers. Here we meet with such realities as self-consciousness,

perception, intellection and volition. Are these material entities of

such character that we may say they are exclusively products of the

activity of the brain, as the secretion of bile is the product of the

activity of the liver, as Cabanis taught? To us it seems clear that

such is not the case. One cannot take the specific gravity of love or

hate, of fear or joy, as one can that of bile; one cannot find a single

physical characteristic in any psychic phenomenon. The most physical of

all mental processes, viz., perception, has its psychological as well

as its physiological phases. The instreaming, through the senses, of

impressions from the external world, may be traced by the physiologist

along the different nerves of the body to the cortex cells of the brain.

All the phenomena that occur at and between these cortex cells and the

peripheral endings of the nerves may be formulated in terms of molecular

physics. But not so with that consciousness of these impressions which

we call perception. In the light of the present knowledge that we

possess, it seems to us that the only induction which the physiologist is

warranted in making is that, associated with molecular movements in the

brain is the phenomenon of perception. This leaves the field clear for

each thinker to speculate about the subject in such manner as seems to

him most rational. And the history of philosophy shows that many thinkers

have formulated theories upon the subject that range in character from

the materialism of Büchner to the idealism of Berkeley.

The view which teaches that psychic phenomena are correlated with

the physiological phenomena of the brain; that these phenomena have

undergone parallel[17] evolution, and “are as inseparable as are the

two sides of a sheet of paper” (Dr. Carus), appeals to us as the most

comprehensible one and at the same time the one most in consonance with

the known phenomena. We accept the view, then, that there is a mind

immanent in the brain.[18] The mind is conscious of its personality;

conscious of the external world through the innumerable perceptions

which reach it through the nervous system; conscious of its power to

build its percepts into concepts, and to reason about them; conscious

of its power of choice and of causing motion; and conscious of itself,

therefore, as a cause in producing effects; and, finally, it is conscious

of its power to adapt means to an end,—in short, it knows that it has the

power to design.

These facts are at the bottom of much of the philosophy of the present

and the past. The untutored savage, knowing that his personality can

cause motion, and beholding moving objects in nature, instinctively made

the induction that all these objects had personalities behind them. He

saw a spirit in his own voice that came back to him as an echo from

the rocks; he saw a personality in his shadow; he saw personalities in

falling stones, in running brooks, in waving foliage; he beheld them in

the raging tempest, in the thunder and the lightning, as well as in the

blazing sun and the twinkling stars; he saw spirits in the dead that came

back to him in dreams. In short, he recognized a separate personality

in every isolated phenomenon in nature. The child talking to its doll,

petting it, rebuking it, or whipping it; Xerxes castigating the ocean

for wrecking his ships, are illustrations of the strong human tendency

to project (or eject)[19] personalities into the inanimate objects of

nature. This natural, but lowly, phase of culture and philosophy is known

as _Fetichism_.

As encephalic and psychic evolution advanced; as men, with wider

knowledge and broadening experience, ascertained the laws that govern

the isolated phenomena of nature, the separate beings in every distinct

object and occurrence vanished from thought; but they still beheld a

separate personality in every great department of nature. The Romans,

for instance, saw Neptune as God of the Ocean, Pluto as God of the lower

world, Jupiter as God of the Heavens, and so on. This phase of culture

and philosophy, and therefore of religion, is _Polytheism_.

In the two phases of culture now briefly outlined the personalities

were grossly anthropomorphic. They were like human beings, capricious,

revengeful, subject to flattery, good and evil, and were therefore to be

placated and cajoled by sacrifices and offerings.

Psychic evolution continuing, there appeared from time to time great

thinkers who saw one “Infinite Personality” behind the cosmos.[20]

This “personality” is still in every phenomenon, though no longer as a

separate soul, but only as the separate manifestation of the Soul of

the Universe. This is _Monotheism_, a phase of culture which marks the

culmination of philosophy and religion through psychic evolution.

Our knowledge of the universe can be only a shadowy symbol of the

reality. The poverty of language is so great and the power of thought so

limited that the most subtle philosopher can form only an empty symbol

of the cosmic soul. The most ethereal symbols of the greatest thinkers

are necessarily incomplete in detail and anthropomorphic, in order to be

intelligible. The history of philosophy and religion shows that with the

evolution of mind and the acquisition of knowledge, the anthropomorphic

ideas of the soul of the cosmos become less crudely coarse and vulgar,

until the most elevated and refined ideas of monotheism are reached. But

even these refined ideas about the soul of the universe are necessarily

anthropomorphic, though in a vastly less degree than in the lower phases

of culture. One’s conceptions of this all-pervading soul immanent in the

universe are therefore profoundly modified by one’s kind and degree of

culture. In the words of Professor Fiske, the great scholar and subtle

thinker who has delved in the deepest mines of philosophy and come forth

weary and heavy-laden with their boasted treasures, has framed a very

different conception of God from that entertained by the priest at the

confessional.

A study of the human brain, then, and the soul resident therein prepares

us to believe that the cosmos has a soul (God) immanent in it. We can

readily grasp the idea that the soul of the cosmos may be self-conscious,

wills, thinks, acts, and designs.

This cosmic soul has been and is active in creation. In a low phase of

culture every distinct object of nature is looked upon as a separate

creation—a manufacture. With the progress of science the conception of

separate creative acts becomes greatly modified. The creative acts are

judged to be fewer in number and nobler in character. Finally, that phase

of highest culture which recognizes the law of universal evolution,

formulates the view of one continuous creative act, in which every

object is still a creation but not a separate creation,—only a separate

manifestation of one eternal act of creative energy. The history of

creation, which means the same thing as the history of evolution, shows

innumerable adaptations which may surely be considered as the work of

a cosmos designer. Evolution has profoundly modified our conceptions

of design in nature as it has those of creation. Every separate work

of nature, presents a separate, distinct and man-like design to the

uncultured. But, with advancing science, all these separate and petty

designs are swallowed up into fewer and grander designs, until at last,

through evolution, we reach the magnificent and ennobling conception of

one infinite and all-embracing design, persisting through infinite time

and extending throughout infinite space, which embraces every apparently

separate design.

Thus, while evolution destroys low anthropomorphic notions of the mode

of working of the Designer and simplifies while it purifies and vastly

ennobles our conceptions of this Designer, it yet replaces as much

teleology as it destroys. But the highest conceptions that the subtlest

philosophers are able to form of a cosmic Designer are necessarily

anthropomorphic in some degree, for they can only think in man-like ways.

We have seen in earlier pages of this book how, throughout the

incalculable ages of geologic time, innumerable living forms have

come upon the stage at different epochs, the forms of one epoch being

transmutations from those of an earlier one, and so on, back to the

beginning of life. The theory of universal evolution teaches that in

the abysmal depths of still earlier æons there was a time when no life

existed on the globe, for the globe was then a whirling ball of intensely

hot vapor; still further back there was a time when this ball of vapor

had not yet been born from that giant nebula—the primitive sun. Through

all the sweep of infinite time we see the multitudinous objects of

nature coming into existence, one after another, from primeval vapor,

and in accordance with laws the character and scope of which we begin to

partially understand. It is after the recounting of such well-known facts

as these that Professor Fiske makes the statement that Paley’s simile of

the watch is no longer applicable to such a world as ours. It must be

replaced, he says, by the simile of the flower; for the universe is not a

machine, but an organism with an indwelling principle of life; the world

was not made offhand, it has grown from more primitive conditions.

In studying the Diagram of Development (Fig. 18) it will be observed that

man is the highest and greatest fruitage of the tree of animal life. He

is the highest animal in the taxonomic series, as he is in the phylogenic

series. He has been the goal, and is the completion of organic evolution.

As Dana says, “there is a prophecy of man which runs through the whole of

geologic history, which was uttered by the winds and waves at their work

over the sands, by the rocks in each movement of the earth’s crust, and

by every living thing in the long succession, until man appeared to make

the mysterious announcements intelligible.”

The vital path from primitive protozoan to man has been a straight

and narrow one, and innumerable groups of animals have branched off

laterally. In so doing they departed forever from the man-ward path, and

developed obliquely along the diverging roads and bypaths of lower life

organizations. They may diverge still farther from the original parting

point, but can never get back into the man-ward road. They have lost the

golden opportunity and can never regain it.

Man is not only the highest creature that has ever appeared on the globe,

but it seems a safe induction to say that he is also the highest animal

that evolution will ever develop here.[21] Evolution, through Natural

Selection and other agencies, having spent most of its force in creating

the innumerable species of animals and plants that have lived in the past

and that are now living on the globe to-day, and having had as its goal

the creation of that highest and noblest of all creatures—man—is now

concentrating its force in further evolving man. Anatomists have reasons

to believe that man is now evolving, in many portions of his body, as

rapidly as did the horse through Tertiary Ages. Evolution is pushing him

on to higher and higher planes, along the straight and perpendicular

man-ward track that he has traveled from his protozoan ancestors; while

his simian relatives are diverging obliquely more and more from the

man-ward track. Through Natural Selection and _rational selection_

evolution seems now to be spending its main force especially on one

particular part of man’s body, viz.: his brain and its immanent mind.

The brain of a living, highly civilized man is larger than the brains

of men of the tenth century; the brains of these latter are larger than

those of palæolithic men. Evolution, having raised the body of man to

nearly its highest possible level, is now perfecting more and more his

brain, and therefore his thinking power, or, better, his mind. Through

his intelligence he is eliminating more and more the noxious plants and

dangerous animals that surround him, and is preserving and improving

those that are useful to him, and thereby making the organic world more

and more subservient to his purposes. He is even getting larger and

larger control over the mechanical, physical, and chemical forces of

nature, and the possibilities of his improvement in these directions are

almost boundless. Evolution for man now means psychic evolution, social

evolution; in short, civilization.

From what has been said it can readily be perceived that man,

zoölogically and psychologically, is by far the most important creature

on the globe. He seems to be the goal towards which evolution has

been steadily advancing throughout the geologic ages. It is for these

reasons that we believe no higher animal than man will be evolved on

the earth. Man himself will continue to evolve higher and higher. Well

may we say, with Sir William Hamilton, that there is nothing great

in the world but _man_, and nothing great in man but _mind_. Is it

a shallow philosophy which teaches that it was through design that

this most important creature was evolved as the topmost flower on the

highest and straightest branch of the tree of life? We do not think so.

One of the most profoundly interesting facts to be observed in that

higher evolution—psychic evolution—which is now mostly molding man,

is the fact of rational selection supplementing and largely replacing

Natural Selection. With the creation of man, _choice_ or will comes in

as a factor of ever-increasing importance. The active will to _use_

certain capacities and _disuse_ others will play a part in the further

development of man of ever-increasing importance and widening influence.

Use and disuse have been factors of commanding importance in modifying

the bodies and minds of the animal forms that led up to man. Use and

disuse will be factors of commanding influence in profoundly modifying

the brain, and therefore the mental constitution of man as he advances

in social evolution. The use of the brain along chosen lines will, on

well-known physiological principles, increase its organization and

therefore its power for manifesting psychic phenomena. These two factors

will continue to act and react in the future as they have in the past,

increased psychical activity enlarging the brain, and the more highly

organized brain augmenting the psychic phenomena. What is true of the

mind in general is also true of its varied manifestations. The history of

psychic evolution gives reason to believe that not only will the capacity

for thought be augmented and the power of the will increased in future,

but also the strength of selfishness will still further be weakened by

disuse and the power of sympathy augmented by practice. As our half-human

ancestors were evolving man-ward, and Natural Selection was augmenting

their brains, thus increasing their capacity for thought and, therefore,

their capacities for more varied experiences through life, there was a

concomitant increase in the period of infancy. The activities of the

lower animals are mostly of a simple character. They are for the purpose

of securing food, escaping enemies, and reproducing their kind. These

activities are comparatively so simple and have been repeated so often,

generation after generation for ages, that they have become thoroughly

organized, by heredity, in the offspring before they are born. When the

offspring are born they seek their food, they endeavor to avoid enemies,

and in due time procreate their kind without any teaching. With them

heredity is almost everything, and experience exceedingly small. These

facts can well be exemplified in studying the young of such animals

as fishes, amphibians, and reptiles. In the higher birds and mammals

Natural Selection has so augmented the size of the brain that their

psychic capacities are greatly increased. This increased intelligence is

accompanied with an augmented variety and complication of experiences.

The acts performed by animals now become so complex, numerous, and varied

that they are repeated with much less frequency than are the acts of

animals lower in the scale. Consequently, heredity has not had sufficient

time to so mold them into the germ-cells that they unfold as perfect

reflex or instinctive acts at birth. The hereditary units that carry

these acquired experiences of the parents in the developing embryo lie

dormant for a while and unfold slowly under the teaching and protection

of the parents for a varying period known as infancy. As Natural

Selection still further evolved the brains of our advancing half-human

ancestors, thus increasing their intelligence and making their lives

more replete with complex and varied experiences, there was a concomitant

prolongation of the period of infancy—the period of helplessness and

dependency. During this evolution of infancy Natural Selection compelled

the parents, especially the mother, to possess feelings other than those

of utter selfishness. They had to give thought not only to themselves but

also to the helpless creatures they brought into the world. The offspring

increasing in numbers, all associated together in varying degrees of

helpless infancy and dependent upon the care and protection of common

parents, the relationships of mother and father, brother and sister, must

by degrees have become more and more intimate as evolution proceeded,

until finally that social unit appears—the family. In the family personal

selfishness can no longer be the exclusively dominant motive to action.

Rudimentary sympathies appear. The individuals must conduct themselves so

as not to jeopardize the interests of the family. Thus other interests

than those of a purely personal character must influence their actions.

And thus, finally, the adumbrations of right and wrong conduct appear,

and we now find in the newly-created human species the germs of morality

and conscience. As social evolution proceeded, the self-regarding

faculties were more and more curtailed, and the other-regarding

sentiments were extended with ever-enlarging amplitude. Sympathy and

helpfulness for others were broadened more and more, including first the

clan, then the tribe, then the nation, and, finally, groups of the latter

were welded into empires. And the writing on the wall seems to indicate

the future federation of all the nations.

Among primeval men, who obtained their food by hunting out such edible

objects as were already in existence, war was universal. The supply of

fruit, fish, and game being strictly limited, men were compelled to

fight under penalty of starvation. As intelligence advanced and men

learned to cultivate useful plants and to domesticate animals, and as

they learned further to exchange by barter the products of their labor,

a much greater population could live upon a given area. These tribes

would be more powerful than their neighbors who still lived by hunting,

fishing, and such like, and would flourish at their expense. Through

agriculture and commerce men slowly learned that one man’s interest was

not necessarily opposed to another’s; they also learned, though it may be

ever so feebly, that fighting and plundering one another hindered rather

than promoted their welfare. Thus man slowly evolved from a primitive,

predatory civilization, in which war was universal and chronic, to the

higher industrial civilization, in which war is much less frequent and

less universal. Out of this primitive industrial civilization, which

has grown more and more complex with the passing years, have come the

arts and sciences, which give such added interest and value to modern

life. This evolving industrial civilization, by furnishing a wider

basis for political union through community of interest instead of mere

blood-relationship, has greatly extended the field over which moral

obligations are recognized as binding.[22] Social evolution is tending

to eradicate more and more, through disuse, the brutish instincts of

man; weakening his fighting propensities, his cruelty, his selfishness,

his passions; and strengthening, by use, his sympathies, his kindness,

his mercy, his sense of justice and honor, and his charity. The goal of

social evolution seems to be _men of character_,—men with the widest

possible knowledge of the laws of nature, physical, intellectual, and

moral; and with the desire and will to rightly obey these laws. Such

men will be both loving and lovable characters. In view of this may we

not supplement Sir William Hamilton’s aphorism, and say that there is

nothing great in mind but character? Since evolution is producing such

characters, though it may be seemingly ever so slowly, is it again a

shallow philosophy which teaches that there is a designer unfolding these

characters? We do not think so. And if there is a designer who has been

making towards this goal throughout the infinite sweep of bygone ages,

do we not have at least some faint adumbration of knowledge as to the

character of this designer? It seems to us that we do. Well may we say,

with Matthew Arnold, that there is immanent in the cosmos an eternal

soul, not ourselves, that makes for righteousness. This double assertion,

that there is a soul in the universe outside of ourselves, and that this

soul makes for right conduct, is the basis of fundamental importance in

all religions. There are many religions in the world, and many creeds

of the one great religion of christendom. They differ in many of the

transcendental doctrines that they teach, and in many of the rules of

conduct that they prescribe for their adherents; but they all contain as

their most fundamental and vitally important basis the double assertion

that there is a soul of the universe, and that this soul makes for

right conduct. The assertion may be thickly overlaid with superstitions

and petty rites by the untrained and dull intelligence of low races,

as in the Eskimos; or it may attain a high degree of development and

perfection, as among the Jews. The refinement and beauty of the double

conception are more and more enhanced with social evolution. Just

in proportion as civilization advances, and men come to reason more

carefully and entertain wider views of life, just to that extent do they

come to value more highly the essential truths of religion, while they

attach less and less importance to many superficial details. It is of

vastly greater moment to us that there is a cosmic soul in the universe

that makes for righteousness than that this soul is threefold or onefold

in its transcendental nature. Also of vastly more moment to us is a

belief in this soul than any opinions we may entertain about eating meat

on Friday or listening to attractive music on Sunday. A thoughtful mind,

penetrated with the conviction of the truth of evolution, entertains

views on all subjects pertaining to man, very different from those held

by one not familiar with the great theory. His conceptions of the first

Adam are profoundly modified by a flood of facts. If this flood sweep

him on irresistibly, and equally profoundly modifies his conceptions of

the second Adam, can it not be seen that even this is a fact of small

significance compared with that other fact of overwhelming importance,

viz.: the fact of the existence in the universe of a cosmic soul that

makes for righteousness? Man is essentially a religious animal, and

there is a very substantial philosophical basis for his religion.[23]

His religion may be highly colored with emotion, or it may be coldly

philosophical. When Herbert Spencer speaks of the eternal Power in the

universe which makes for righteousness and is manifested in every event

of the universe as the Unknowable, does he not do what Holy Writ has

already done? “Canst thou find out the Almighty unto perfection?” When

Carlyle speaks of the Universe as in very truth the star-domed city of

God, and reminds us that through every crystal and through every grass

blade, but most through every living soul, the glory of a present God

still beams, he means much the same thing that Mr. Spencer does when

he speaks of a Power that is inscrutable in itself, yet is revealed

from moment to moment in every throb of the mighty rhythmic life of

the universe. The only difference is that Mr. Spencer speaks in the

colorless, precise, and formal language of science, while Carlyle’s

language is colored by emotion; is, in fact, poetical.[24]

EVOLUTION AND SOCIAL PROBLEMS.

The relation of evolution to many social problems of vital importance

is a fascinating as well as very extensive subject. We have only space

to say that in order to understand the normal actions, as well as the

abnormal ones, of the members of society, and in order, therefore, to

understand and inaugurate rational methods of conducting education,

minimizing pauperism, vice, disease, and crime, it must constantly be

borne in mind that two great streams of tendencies have come down from

the ages in the germ cells—what we may call the diseased and animal

tendencies on the one hand, and the distinctively human and healthy

tendencies on the other.

The most characteristic of the human tendencies are abstract thought and

reflection, and therefore the power of choice or will, and altruism.

Also it must be borne in mind that environment is a force of commanding

influence. This environment (which the individual may make for himself

to a limited extent) may be propitious or adverse to the best human

and normal tendencies. The relative preponderance of the animal or the

human, the healthy, or the diseased tendencies, taken in conjunction with

the character of the environment, stamp man’s actions as normal (and

therefore right or wrong) or as abnormal, and therefore irresponsible.

Not to discriminate between such normal and abnormal persons is not in

accordance with either common morality or common sense. Neither is it

in accord with common sense, or morality, or humanity, for society to

deal with its habitual criminals and paupers, and subjects of hereditary

disease, in the utterly irrational manner that it does. When society

takes away from the criminal his personal liberty and places him in an

environment that theoretically reforms him and protects itself, why does

it not take cognizance of the fact that its theories are often woful

failures in practice? The criminal is often not reformed and he gets

into the category of habitual offenders; but society permits him, during

his intervals of freedom, to procreate his kind and send his polluted

cargoes of vicious heritages to helpless offspring. Is this humanity to

these offspring? It is the grossest inhumanity! Does society protect

itself by its intermittent detentions of habitual criminals? It probably

breeds three habitual criminals while it is failing in its efforts to

reform one. It is mostly by Nature’s prematurely killing off incorrigible

criminals by their diseases and intemperance, that these social pests

are kept within due bounds, and not through reformations accomplished in

improperly conducted prisons. It seems to us that every consideration of

justice and humanity cries aloud for the destruction of the procreating

glands in _habitual criminals_.[25] Castration should go hand in hand

with detention behind prison bars. Why should the habitual drunkard, for

instance, be permitted to evolve his poisoned germ cells into helpless

beings, giving them diseased bodies and vitiated moral characters, thus

foredooming them to life-long physical ailments and moral turpitude?

Removal of the procreating glands should be the penalty for chronic

alcoholism. In objection to this suggestion, some may prate of personal

liberty. What a multitude of outrages and brutalities the broad mantle of

personal liberty is often made to cover! In allowing personal liberty to

an undeserving individual, which more often means unbridled license to

that individual, a whole generation of offspring are frequently enslaved

by poverty, vice, crime, and disease in its manifold manifestations.

During organic evolution Natural Selection has been incessantly on the

watch for weaknesses of any kind, ruthlessly exterminating the helpless,

the weak, the sick, and those that in any way are unfit. In social

evolution Natural Selection has often been of necessity no less ruthless.

But during social evolution characters that are unfolding more and more

loving and lovable traits have so largely subordinated Natural Selection

as to permit the helpless, the old, the sick, and the unfit, to live,

thus strengthening those highest attributes of the greatest minds, viz.:

intelligent sympathy, pity and love.

But it seems to us that the highest altruism, in dealing kindly with an

abnormal, possible parent, will not continue long to stupidly overlook

the weighty rights of unborn children. Human selection of the socially

unfit will be dominated more and more, as social evolution unfolds

its fruits, by those minds that are advancing to the highest goals of

evolution, viz.: large minds of high character—widely informed minds, of

strong will and broad sympathies. And under these circumstances we may

hope that unborn generations will not be given over to total oblivion.

Well may we repeat, before concluding this little book, that man is not

only a creature of the present, but profoundly a product of the abysmal

ages of a bygone eternity. He is not only a composite chip of many old

human blocks, but of innumerable geologic ancestral blocks. He has in his

constitution simian, reptilian, piscine, and innumerable other chips,

so to speak, and is indeed of the earth earthy; for studies in heredity

not only illustrate the continuity of the human race, but also clearly

indicate the continuity of this race with more lowly animals. Man has

in his structure the indelible impress of the handiwork of these lowly

relatives. Upon him, as upon them, and upon all living creatures, the

forces of heredity and variation, of use and disuse, of environment and

Natural Selection, have been and are perpetually playing, evolving him in

one direction and innumerable creatures in other directions.

The goal of evolution seems to be men with Great Minds of High Character.

_There is nothing great in the world but man, nothing great in man but

mind, and nothing great in mind but character._

SECTION VII.

CLASSIFICATION OF ANIMALS AND PLANTS.

A SYNOPSIS OF THE ANIMAL KINGDOM.

In order that the reader may appreciate to some extent the relative

positions of the different groups of animals, extinct and living, in the

scale of life, the following brief classification may be useful. This

synopsis is especially intended to help readers who are not familiar

with elementary zoölogy to understand the significance of the different

types of animals found in the strata of different geologic periods, and

more particularly to grasp the meaning of the Diagram of Development. The

animals are usually mentioned in the order of their position in the scale

of life, commencing with the lowest and simplest.

SYNOPSIS OF GROUPS.

A. PROTOZOA. Unicellular animals, dissociated, or associated in simple,

loose colonies of similar organisms. Many have an exoskeleton of lime,

flint, or other material. Reproduction by fission and by temporary or

permanent conjugation.

B. METAZOA. Multicellular animals, consisting of a large number of cells

associated together to form single, complex individuals. The cells of

an individual are usually differentiated into several kinds performing

special functions. Reproduction in the higher forms is sexual; in the

lower forms it is often by budding as well as sexual.

SYNOPSIS OF THE BRANCHES OF ANIMALS.

GROUP A. PROTOZOA.

Branch I.—=Protozoa.= Characteristics already defined.

Class 1.—_Monera._

Class 2.—_Rhizopoda_: Amœba, Arcella, Foraminifera, Difflugia, Quadrula.

Class 3.—_Gregarinida_: Gregarina.

Class 4.—_Infusoria_: Noctiluca, Paramecium, Stylonychia.

GROUP B. METAZOA.

Branch II.—=Porifera.= Sponges are animals with their cells arranged in

two well-defined layers, one of which is internal (endoderm) and the

other external (ectoderm). There is a middle stratum of cells (mesoglœa)

which does not attain to the definiteness of a mesoderm. Sponges do not

possess a body cavity (cœlome); they possess, essentially, a bilateral

symmetry. The body varies greatly in shape, and is traversed by canals

having large openings (oscula) and numerous small openings (pores) on

the surface. The ectoderm is continued through the pores into afferent

canals; the endoderm cells line most of the internal (efferent) cavities,

and are mostly flagellate; the mesoglœa contains a skeleton of flint,

lime, or spongin. Reproduction may be by budding or sexual (either

hermaphroditic or unisexual).

Branch III.—=Cœlenterata.= Animals possessing radial symmetry. There

is no body cavity (cœlome), but there is a primitive digestive cavity

(enteron). The body consists of two layers, an ectoderm and endoderm;

between these two layers there is a mesoglœa of jelly-like consistency;

in the simplest cases there are no cells in the mesoglœa, but secondarily

endodermal cells may migrate into it. Stinging cells are generally

present.

There are two divergent types of structure. The more primitive one is the

sessile tubular hydroid, which may be compared to a gastrula furnished at

one end with a crown of tentacles surrounding the opening of the enteron,

and fixed at the opposite end. The less primitive, derived form, is the

active jellyfish (medusoid) type. The hydroid type often constructs a

calcareous skeleton known as coral. One life history may present both

types (alternation of generations). Reproduction is sexual or by budding,

in the latter case often resulting in the formation of colonies.

Class 1.—_Hydrozoa_: Hydra, Jellyfish.

Class 2.—_Actinozoa_: Sea-Anemones, Coral Polyps.

Class 3.—_Ctenophora_: Comb-Bearers.

Branch IV.—=Echinodermata.= Animals, the larvæ of which possess bilateral

symmetry, while the adults have radial symmetry. Even the adults exhibit

to a varying extent a tendency to bilateral symmetry. Lime is always

deposited in the mesodermic substance (mesenchyme). From the primitive

digestive canals of the larvæ pouches grow out to form the usually

spacious body cavity and the characteristic water vascular system. The

latter and the nervous system exhibit generally a typical five-rayed

arrangement. During development there is a distinction between mesoblast

derived from gut pouches and mesenchyme produced from migrated amœboid

cells. Complicated metamorphosis.

Class 1.—_Cystoidea._

Class 2.—_Blastoidea._

Class 3.—_Crinoidea_: Stone-lily.

Class 4.—_Asteroidea_: Star-fishes.

Class 5.—_Echinoidea_: Sea-urchins.

Class 6.—_Holothuroidea_: Sea-cucumbers.

Branch V.—=Vermes.= The term “worms” includes a “heterogeneous mob,” a

collection of classes whose relationships are poorly understood. But

they are of great zoölogical interest, for, amid the diversity, there

can be discerned affinities with Cœlenterata, Echinodermata, Arthropoda,

Mollusca, and Vertebrata. They possess a well-defined mesoderm. They

possess bilateral symmetry and have, as a rule, a head, tail, dorsal

and ventral surfaces, and right and left sides. The lower worms are

unsegmented. In the higher ones the digestive tract extends from the

head to the end of the body; a dorsal vessel is usually present above

the digestive tract; the nervous system consists of a supra-œsophageal

ganglion (brain) and a simple or more commonly double, ventral,

ganglionated cord; there is a body cavity (cœlome) lined with mesoderm;

true jointed appendages are never present.

Class 1.—_Platyhelminthes_: Flat-worms.

Class 2.—_Nemathelminthes_: Round-worms.

Class 3.—_Rotatoria_: Rotifer.

Class 4.—_Bryozoa._

Class 5.—_Brachiopoda_: Lampshells.

Class 6.—_Nemertina._

Class 7.—_Enteropneusta_: Balanoglossus.

Class 8.—_Gephyrea_: Star-worms.

Class 9.—_Annulata_: Earth-worms, Leeches, Sea-worms.

Branch VI.—=Arthropoda.= Animals with bilateral symmetry. Bodies

segmented, but not uniformly so. Several or all of the segments bear

paired jointed appendages variously modified. Chitinous exoskeleton.

Digestive canal beneath the heart. Supra-œsophagel ganglion (“brain”)

connected by a nerve ring round the gullet with a double chain of ventral

ganglia. Cœlome small in the adult. Sexes almost always separate. Often

some metamorphosis.

Class 1.—_Crustacea_: Trilobites, Shrimps, Crabs.

Class 2.—_Arachnida_: Spider, Scorpion.

Class 3.—_Onychophora_: Peripatus.

Class 4.—_Myriapoda_: Centipede.

Class 5.—_Insecta_: Cockroach, Ants, Butterfly.

Branch VII.—=Mollusca.= Unsegmented animals, possessing, fundamentally,

a bilateral symmetry. A very characteristic structure is the “foot”—a

muscular protrusion of the ventral surface. Typically, a projecting fold

from the dorsal surface of the body forms a mantle, or pallium; the

mantle often secretes a single or double shell covering the viscera.

The mantle and shell may both be absent. The central nervous system

consists of paired ganglia with connecting commissures, viz.: cerebral,

pleural, pedal, and visceral ganglia. Heart possesses two auricles and

one ventricle. Respiration generally by gills. Frequently there are two

larval stages. Development is often direct.

Class 1.—_Lamellibranchiata_: Clam, Oyster.

Class 2.—_Scaphopoda._

Class 3.—_Gasteropoda_: Snail, Whelks, Slugs.

Class 4.—_Amphineura_: Chitons.

Class 5.—_Cephalopoda_: Squids and Cuttlefish.

Branch VIII.—=Vertebrata or Chordata.= Vertebrates are animals having a

distinct body cavity (cœlome) and a segmental arrangement of parts. A

hypoblastic skeletal notochord is always present in the embryo, but tends

to be replaced by an axial skeleton of mesoblastic origin (backbone).

Gill slits are always present in the embryo and may or may not persist in

adult life. Gill-lamellæ do not occur above Amphibians. Heart is ventral.

Central nervous system is dorsal. Eye begins to develop as an outgrowth

from the brain.

Class 1.—_Tunicata._

Class 2.—_Leptocardii._

Class 3.—_Marsipobranchii._

Class 4.—_Pisces._

Class 5.—_Amphibia._

Class 6.—_Reptilia._

Class 7.—_Aves._

Class 8.—_Mammalia._

Class 1.—_Tunicata._ The tunicates are remarkable animals, and seem

to stumble on the border line between Invertebrates and Vertebrates.

Their vertebrate characteristics—gill slits, notochord, dorsal nervous

system, and brain eye—are generally discernible only in the free-swimming

larval state. They generally degenerate as they progress towards the

adult condition, and diverge greatly from the vertebrate type. They are

mostly stationary. They are multicellular animals possessing bilateral

symmetry. The body is enveloped by a thickened cuticle containing

cellulose. The pharynx, perforated with the gill slits, is surrounded by

a peribranchial chamber (atrium) which communicates with the exterior

by an atrial opening. Heart is simple and tubular. The nervous system

is generally reduced to a single ganglion. Nephridia are absent.

Hermaphrodites. Usually a metamorphosis.

Class 2.—_Leptocardii._ Simple, worm-like vertebrate animals represented

by a single distinct type—amphioxus or lancelet. The central nervous

system consists of a spinal cord, and a very ill-defined, rudimentary

brain. No skeleton other than an unsegmented and persistent notochord

which projects beyond the anterior end of the nerve cord. No scales. Gill

slits are very numerous in the adult. Amphioxus is widely removed from

the fishes by the absence of skull, jaws, definite brain, sympathetic

nervous system, ear, eye, genital ducts, spleen, and definite heart, the

latter being simple and tubular. No pectoral or pelvic limbs (fins).

Blood colorless; gastrula ciliated and free-swimming. Metamorphosis.

Class 3.—_Marsipobranchii._ Worm-like vertebrates having round mouths

without distinctly developed jaws; no jaw-bones. Without scales and

without paired limbs (fins). Six or seven gill pouches. Skeleton consists

of persistent, unconstricted, cartilaginous notochord. No sympathetic

nervous system. Single nasal sac. No conus arteriosus, no spleen or

pancreas. Undivided segmental duct.

Class 4.—_Pisces._[26] Aquatic, cold-blooded vertebrates, with a movable

lower jaw. Cartilaginous or osseous skeleton, with paired pectoral and

pelvic fins, supported by fin rays (_radials_ diverging from several

_basal_ pieces); also unpaired fins. No sternum. Exoskeleton of bony

plates or scales. Skull has usually one occipital condyle. Breathing

by permanent gills attached to gristly or bony arches on the sides of

the gill clefts. In most fishes the digestive cavity gives origin to an

air bladder which may or may not remain permanently connected with the

digestive cavity. It mostly serves a hydrostatic purpose, but in some of

the more primitive fishes (Amia, Lepidosteus) it is occasionally of some

slight use in respiration. Heart consists of single auricle and single

ventricle, and contains only venous blood; there is a sinus venosus and

often a conus arteriosus. No inferior vena cava. No allantois. Most

fishes lay eggs which are fertilized in the water.

Sub-class 1.—_Elasmobranchii._

Order 1.—_Plagiostomi_: Sharks, Rays.

Order 2.—_Holocephali_: Chimæroids.

Sub-class 2.—_Teleostomi._

Order 1.—_Crossopterygii_: Polypterus, Calamoichthys.

Order 2.—_Ganoidei_: Sturgeon, Garpike, Amia, Polyodon.

Order 3.—_Dipnoi_: Lung-fishes, e. g., Ceratodus, Protopterus, and

Lepidosiren.

Order 4.—_Teleostei_: Perch, Cod, Salmon, Eel.

Class 5.—_Amphibia._ In the evolution of vertebrates the Amphibians

represent those forms which made the transition from aquatic to

terrestrial life, but have lingered near the water. Certain acquisitions

gained by the Dipnoi, such as a three-chambered heart and lungs, have

been accentuated and firmly established by the Amphibians.

Amphibia are cold-blooded vertebrates whose larval forms always have

gill arches bearing gills. In some forms the gills are retained

throughout life, though the adults always possess functional lungs.

Nasal sacs open posteriorly into the mouth. In existing forms there

is rarely any exoskeleton. There are two occipital condyles. Unpaired

fins are frequently present, though they possess no fin rays. When

limbs are present they possess distinct digits and conform to the same

type as those of the higher vertebrates. Heart has two auricles and

one ventricle. There is an inferior vena cava. The intestine ends in a

cloacal chamber, as do also the urinogenital ducts. Eggs almost always

laid in the water. Often a marked metamorphosis.

Order 1.—_Urodela._ Amphibia which retain the tail throughout life.

The order is subdivided into:

a. _Perennibranchiata_, which retain the gills throughout life:

_Siren_, _Proteus_.

b. _Caducibranchiata_; no persistent gills: _Triton_, _Salamandra_.

Order 2.—_Gymnophiona._ Body snake-like; no feet; young with gills:

_Cœcilia_.

Order 3.—_Stegocephala._ Extinct forms: _Archegosaurus_.

Order 4.—_Anura._ Tailless amphibia; body short, with four limbs;

larvæ tailed: _Frog_, _Toad_.

Class 6.—_Reptilia._ Cold-blooded, air-breathing vertebrates. Limbs

usually ending in claws; limbs sometimes absent; exoskeleton of

scales; ribs well developed; incomplete double circulation; heart is

four-chambered in the highest forms; oviparous; no metamorphosis; embryo

with an amnion and allantois.

The following are some of the orders that have become extinct, viz.:

a. _Theromorpha_: Mammal-like saurians.

b. _Ichthyosauria_: Swimming saurians.

c. _Pterosauria_: Flying saurians.

d. _Dinosauria_: Colossal land saurians capable of rising and resting

on the hind legs.

The following are the living orders, viz.: a, _Ophidia_; b, _Lacertilia_;

c, _Chelonia_; d, _Crocodilia_.

Class 7.—_Aves._ Feathered vertebrata; heart four-chambered;

warm-blooded; lungs with accessory air-sacs; bones dense and hollow;

jaws encased in horny beaks in modern forms; the fore-limbs form wings;

oviparous; eggs are very large and covered by calcareous shell.

Sub-class 1.—_Saururæ_: Archæopteryx.

Sub-class 2.—_Odontornithes_: Ichthyornis, Hesperornis.

Sub-class 3.—_Ratitæ_: Smooth sternum.

Sub-class 4.—_Carinatæ_: Keeled sternum.

Class 8.—_Mammalia._ Animals having the body covered with hair;

warm-blooded; young nourished with milk secreted from mammary glands;

lower jaw articulating directly with the skull, the quadrate becoming the

malleus (ear-bone); heart four-chambered and with the aorta reflected

over the left bronchus; red blood-corpuscles non-nucleated; complete

diaphragm; brain large, especially the cerebrum and cerebellum; uterine

gestation; viviparous.

Sub-class 1.—_Ornithodelphia_: Order Monotremes. Urinary and genital

canals opening into cloaca. Laying large eggs.

Sub-class 2.—_Didelphia_: Order Marsupials. Animals having pouch for

protection and growth of prematurely born embryos.

Sub-class 3.—_Monodelphia_: Placental Mammals.

Order 1.—_Edentata._

Order 2.—_Rodentia._

Order 3.—_Insectivora._

Order 4.—_Cheiroptera._

Order 5.—_Cetacea._

Order 6.—_Sirenia._

Order 7.—_Proboscidea._

Order 8.—_Hyracoidea._

Order 9.—_Ungulata._

Order 10.—_Carnivora._

Order 11.—_Primates._

_Primates_ are an order of Monodelphia or Placentalia, including lemurs,

monkeys, and man. They are nearly all adapted to an arboreal life. The

hand (manus) and the foot (pes) nearly always have five digits provided

with flat nails. The pectoral and pelvic limbs are prehensile, owing to

the fact that the thumb (pollex) and big toe (hallux) are more or less

completely opposable to the other digits. The orbital fossa is completely

surrounded by a bony rim. The femur does not have a third trochanter. The

internal condyle of the humerus does not have a foramen above it. The

clavicles are always well developed. The testes descend into a scrotum.

On the thoracic region there are nearly always two teats. The placenta

may be non-deciduate, or deciduate and metadiscoidal.

The order of Primates is subdivided into the following sub-orders, viz.:

Sub-order 1.—_Lemuroidea._

Sub-order 2.—_Anthropoidea._

_Lemuroidea._ The Lemurs are small, monkey-like quadrupeds. They are

mostly nocturnal, arboreal creatures of comparatively low organization.

The body is furry. The orbital and temporal fossæ freely communicate. The

lachrymal foramen is situated outside the orbital fossa. The dentition

of the Lemurs varies greatly; in some of them it is 2/2 1/1 3/3 3/3 for

both jaws. In nearly all of them the median incisors of the upper jaw are

separated by a median space. Both feet have flat nails on all the digits,

except the second of the hind-foot, which has a claw. The thumb (pollex)

and the big toe (hallux) are well developed. The cerebral hemispheres are

only slightly convoluted, and do not entirely overlap the cerebellum. The

transverse colon is almost always folded on itself. There may be a pair

of teats on the abdomen. The uterus is two-horned, and the placenta is

diffuse.

This sub-order comprises the Lemurs proper (_Tarsius_, _Lemur_, and other

genera) and the Aye-Ayes (_Chiromys_).

_Anthropoidea._ The Anthropoidea are the most highly organized Primates.

They are chiefly modified for an arboreal life. The body is hairy instead

of furry, but only slightly so in man. The incisors do not exceed 2/2;

the molars are 3/3, except in the marmosets, where they are 2/2. The

upper, median incisors are in close contact. The orbital and temporal

fossæ are separated by a broad vertical plate. The lachrymal foramen

is situated inside the orbital fossa. All of the digits are provided

with flat nails, except in the Hapalidæ, in which all except the big

toe (hallux) are provided with a claw. In some the thumb (pollex) is

rudimentary or absent. The clavicle is well developed. The cerebrum

is usually richly convoluted, and more or less completely covers the

cerebellum. The uterus has no horns. The placenta is deciduate and

metadiscoidal.

The Anthropoidea are subdivided into the two following groups:

Super-family 1.—_Platyrrhinæ_ (New-World Monkeys).

Super-family 2.—_Catarrhinæ_ (Old-World Monkeys).

The Platyrrhinæ or New-World Monkeys are subdivided into the following

families, viz.:

Family 1.—_Hapalidæ._

Family 2.—_Cebidæ._

The Catarrhinæ or Old-World Monkeys are subdivided into the following

families, viz.:

Family 1.—_Cercopithecidæ._

Family 2.—_Simiidæ._

Family 3.—_Hominidæ._

_Hapalidæ._ The Hapalidæ or Marmosets are no larger than squirrels, being

the smallest monkeys. They are found mostly in Brazil.

There is a broad septum between the nostrils. Their dentition is 2/2 1/1

3/3 2/2, and is distinctive, for the remaining Anthropoidea have 3/3

molars. The tail is long, hairy, and non-prehensile. The arms are not

longer than the legs. The thumb (pollex) is long, but is not opposable.

All the digits except the great toe (hallux), which is small, have

curved, pointed claws. There is no bony external auditory meatus. There

are no cheek pouches, or ischial callosities. The Hapalidæ often bear

three young ones at a birth, whereas the other Anthropoidea commonly bear

but one. There are two genera of Marmosets, viz.: _Midas_ and _Hapale_.

_Cebidæ._ The Cebidæ are most at home in Brazil. They have a broad

septum between the nostrils. Many of them have prehensile tails. The

dental formula is 2/2 1/1 3/3 3/3, and is characteristic. There is no

bony external auditory meatus. There are no cheek pouches, or ischial

callosities. All the digits are provided with flat nails. The thumb

(pollex) is not opposable.

This family includes the following genera, viz.: Tee Tees (_Callithrix_),

Howling Monkeys (_Mycetes_), Spider Monkeys (_Ateles_), Squirrel Monkeys

(_Chrysothrix_), and Capuchin Monkeys (_Cebus_).

_Cercopithecidæ._ This family includes the Old-World dog-like Apes. They

are quadrupeds, and the muzzle or snout is quite dog-like. There is a

narrow septum between the nostrils. The dental formula is 2/2 1/1 2/2

3/3. The sternum is narrow. The tail is not prehensile. The cæcum has no

appendix vermiformis. There is a bony external auditory meatus. There may

or may not be cheek pouches. Over the rough surface of the everted ischia

the skin forms callosities (ischial callosities) which are often brightly

colored. The thumb (pollex), when present, is opposable. This family

includes two genera, Macaques (_Macacus_) and Baboons (_Cynocephalus_).

_Simiidæ._ This family includes the Anthropoid Apes of the Old World.

They are less quadrupeds than the former, often walking in a semi-erect

position. The dental formula is 2/2 1/1 2/2 3/3. The sternum is broad.

The cæcum has an appendix vermiformis. The nasal septum is narrow. The

pectoral limbs are much longer than the pelvic ones. There is a bony

external auditory meatus. There are no cheek pouches. Only in the Gibbons

are there ischial callosities, in whom they are small. The thumb (pollex)

is opposable. No visible tail. This family includes the following genera,

viz.: Chimpanzees (_Anthropopithecus_), Gorillas (_Gorilla_), Orangs

(_Simia_), and the Gibbons (_Hylobates_).

_Hominidæ._ This family of Anthropoidea includes only the human species

(_Homo sapiens_). The dental formula is 2/2 1/1 2/2 3/3. The tail is

not visible. The Hominidæ differ from the Simiidæ, structurally, mainly

in the more perfect assumption of the erect attitude. There is a more

complete adaptation of the pelvic limbs to bearing the weight of the

body, correlated with compensating alteration in the curvature of the

spinal column. The big toe (hallux) is not opposable, and also it is

often longer, never shorter than the other toes, and is not abducted

from them. He has a far better heel than the Simiidæ. The thumb is far

more opposable in man. There is a greater length of the pelvic limbs

compared with the pectoral limbs. The canine teeth are much smaller and

do not project beyond the level of the others. The brain has a much

greater size and complexity. Man has a larger forehead, smaller cheek

bones, smaller supraorbital ridges, a less protrusive face, and a true,

well-marked chin.

The Simiidæ are subdivided into the two following groups, viz.:

Sub-family 1.—_Hylobatinæ._

Genus 1.—_Hylobates_ (Gibbons).

Sub-family 2.—_Simiinæ._

Genus 1.—_Simia_ (Orangs).

Genus 2.—_Gorilla_ (Gorillas).

Genus 3.—_Anthropopithecus_ (Chimpanzees).

SYNOPSIS OF THE PLANT KINGDOM.

GROUP A. PROTOPHYTA.

GROUP B. METAPHYTA.

The Metaphyta are subdivided into:

1. _Cryptogams_: Flowerless plants.

2. _Phanerogams_: Flowering plants.

The Cryptogams are subdivided into:

1. _Thallophyta_: Seaweeds, Fungi, Lichens.

2. _Bryophyta_: Mosses, Liverworts.

3. _Pteridophyta_: Ferns, Horsetails, Clubmosses.

The Phanerogams are subdivided into:

1. _Gymnospermæ_:

Order a.—_Cycadaceæ_: Cycads.

Order b.—_Coniferæ_: Pines, Spruces, Cypresses.

2. _Angiospermæ_:

Class 1.—_Monocotyledones_: Grasses, Palms.

Class 2.—_Dicotyledones_: Oaks, Poplars, Elms.

SECTION VIII.

WORKS OF REFERENCE.

WORKS OF REFERENCE.

The following books have been the constant companions of the author

during the preparation of his “First Book in Organic Evolution”:—

GRANT ALLEN, The Colours of Flowers.

A. C. ABBOT, Principles of Bacteriology.

FRANK BAKER, The Ascent of Man.

THOMAS BELT, Naturalist in Nicaragua.

H. W. BATES, Naturalist of the Amazons.

F. E. BEDDARD, Animal Coloration.

A. H. BRADFORD, Heredity and Christian Problems.

F. M. BALFOUR, A Treatise on Comparative Embryology.

D. G. BRINTON, Races and Peoples.

P. C. BURT, A History of Modern Philosophy.

PAUL CARUS, The Soul of Man.

PAUL CARUS, The Ethical Problem.

PAUL CARUS, The Idea of God.

PAUL CARUS, Homilies of Science.

PAUL CARUS, Fundamental Problems.

ARTHUR CLARKSON, A Text-Book of Histology.

EDWARD CLODD, The Story of Creation.

EDWARD CLODD, The Story of Primitive Man.

EDWARD CLODD, A Primer of Evolution.

CARPENTER-DALLINGER, The Microscope and its Revelations.

A. DE QUATREFAGES, The Natural History of Man.

E. D. COPE, The Primary Factors of Organic Evolution.

CHARLES DARWIN, The Origin of Species.

CHARLES DARWIN, The Descent of Man.

CHARLES DARWIN, Animals and Plants under Domestication.

J. D. DANA, New Text-Book of Geology.

BASHFORD DEAN, Fishes, Living and Fossil.

J. W. DRAPER, History of the Intellectual Development of Europe.

J. W. DRAPER, Conflict between Religion and Science.

H. H. DONALDSON, The Growth of the Brain.

R. L. DUGDALE, The Jukes.

HENRY DRUMMOND, The Ascent of Man.

HAVELOCK ELLIS, Man and Woman.

HAVELOCK ELLIS, The Criminal.

JOHN FISKE, The Unseen World.

JOHN FISKE, The Idea of God.

JOHN FISKE, The Destiny of Man.

JOHN FISKE, Excursions of an Evolutionist.

JOHN FISKE, Myths and Myth-Makers.

ENRICO FERRI, Criminal Sociology.

SIR W. H. FLOWER, Osteology of the Mammalia.

FUNK and WAGNALL, Standard Dictionary of the English Language.

THEODORE GILL, The Families of Fishes.

THEODORE GILL, Articles on Fishes in the Riverside Natural History.

JOHN C. GALTON, Ecker’s The Human Brain.

FRANCIS GALTON, Hereditary Genius.

FRANCIS GALTON, Natural Inheritance.

FRANCIS GALTON, English Men of Science, their Nature and Nurture.

C. GEGENBAUR, Elements of Comparative Anatomy.

J. M. GUYAU, Education and Heredity.

GEDDES and THOMSON, The Evolution of Sex.

HARPER’S Latin Dictionary.

T. H. HUXLEY, Anatomy of Vertebrated Animals.

T. H. HUXLEY, Man’s Place in Nature.

T. H. HUXLEY, Origin of Species.

T. H. HUXLEY and MARTIN, Practical Biology.

T. H. HUXLEY, Science and Culture, and other Essays.

HERTWIG-MARK, Text-Book of Embryology.

DAVID J. HILL, Genetic Philosophy.

HERTWIG-CAMPBELL, The Cell.

ROBERT HARTMAN, The Anthropoid Apes.

GEORGE HASLAM, Ecker’s Anatomy of the Frog.

REV. W. HOUGHTON, Sketches of British Insects.

E. KLEIN, Micro-organisms and Disease.

G. T. LADD, Outlines of Physiological Psychology.

CESARE LOMBROSO, The Man of Genius.

SIR JOHN LUBBOCK, The Beauties of Nature.

SIR JOHN LUBBOCK, Ants, Bees, and Wasps.

ARNOLD LANG, Text-Book of Comparative Anatomy.

JOSEPH LEIDY, Fresh-water Rhizopoda of North America.

LIDDELL and SCOTT, Greek-English Lexicon.

SIR CHARLES LYELL, Antiquity of Man.

SIR CHARLES LYELL, Principles of Geology.

JOSEPH LE CONTE, Evolution and its Relation to Religious Thought.

JOSEPH LE CONTE, Elements of Geology.

C. S. MINOT, Human Embryology.

ST. GEORGE MIVART, The Genesis of Species.

ST. GEORGE MIVART, Lessons in Elementary Anatomy.

ST. GEORGE MIVART, The Common Frog.

ST. GEORGE MIVART, The Cat.

A. M. MARSHALL, Vertebrate Embryology.

HENRY C. MCCOOK, American Spiders.

F. MAX MÜLLER, Anthropological Religion.

C. LLOYD MORGAN, Animal Life and Intelligence.

C. LLOYD MORGAN, Animal Biology.

O. T. MASON, Woman’s Share in Primitive Culture.

DANIEL OLIVER, Lessons in Elementary Botany.

RICHARD OWEN, Anatomy of Vertebrates.

A. S. PACKARD, Zoölogy.

PARKER and HASWELL, Text-Book of Zoölogy.

OSCAR PESCHEL, The Races of Man.

E. P. POULTON, The Colours of Animals.

J. W. POWELL, Truth and Error, or, The Science of Intellection.

TH. RIBOT, Heredity.

ERNEST RENAN, The Life of Jesus.

G. J. ROMANES, Darwin and After Darwin.

S. H. REYNOLDS, The Vertebrate Skeleton.

OSCAR SCHMIDT, The Mammalia.

OSCAR SCHMIDT, Descent and Darwinism.

SCHAFER and THANE, Quain’s Elements of Anatomy.

KARL SEMPER, Animal Life.

HERBERT SPENCER, Principles of Biology.

W. B. SCOTT, An Introduction to Geology.

N. S. SHALER, First Book in Geology.

J. B. SUTTON, Evolution and Disease.

R. S. TARR, Elementary Geology.

J. A. THOMSON, Outlines of Zoölogy.

E. B. TYLOR, Anthropology.

JAMES TYSON, The Cell Doctrine.

LESTER F. WARD, Dynamic Sociology.

LESTER F. WARD, Outlines of Sociology.

ALFRED WEBER, History of Philosophy.

A. D. WHITE, A History of the Warfare of Science with Theology.

A. WEISMANN, Essays upon Heredity.

A. WEISMANN, The Germ-Plasm.

A. R. WALLACE, The Malay Archipelago.

A. R. WALLACE, Darwinism.

E. B. WILSON, The Cell in Development and Inheritance.

R. WIEDERSHEIM, Comparative Anatomy of Vertebrates.

R. WIEDERSHEIM, The Structure of Man.

C. F. WINSLOW, Force and Nature.

WILLIAM WHEWELL, History of the Inductive Sciences.

B. G. WILDER, Anatomical Technology.

B. G. WILDER, Article “Brain,” Reference Handbook of the Medical

Sciences.

ERNST ZIEGLER, General Pathology.

SECTION IX.

GLOSSARY.

GLOSSARY.

=A-chro´ma-tin= [Gr. _a_-priv.; _chroma_, color.] The nuclear hyaloplasm.

=A-chro-ma-top´si-a= [Gr. _a_-priv.; _chroma_, color; _opsis_, sight.]

Color-blindness.

=Ac-ti-no-zo´a= [Gr. _aktis_, ray; _zoon_, animal.] A division of

Cœlenterates embracing the sea-anemones and coral-polyps.

=Al-lan´to-is= [Gr. _allas_, sausage; _eidos_, form.] A membranous,

sack-like appendage developed from the hinder part of the embryonic

alimentary tract and which serves the purpose of effecting oxygenation

and other changes in the blood in reptiles, birds, and mammals.

=Am-blyp´o-da= [Gr. _amblys_, blunt; _pous_, foot.] An extinct order of

ungulates having elephantine feet and whose navicular bone was supported

by the cuboid.

=Am-blys´to-ma= [Gr. _amblys_, blunt; _stoma_, mouth.] A genus of

amphibians remarkable for the transformations they undergo. When

undeveloped they represent the formerly recognized genus _Siredon_. Some

species are called _axolotls_.

=Am´i-a= [Gr. _amia_, a kind of tunny.]

=Am-i-to´sis= [Gr. _a_-priv.; _mitos_, thread.] Direct cell-division;

cell-division without the formation of nuclear figures.

=Am´mon-ites= [Egyptian _Amon_.] Fossil cephalopod shells.

=Am´nion= [Gr. _amnion_, fœtal membrane.] A membranous sack containing

fluid which envelopes the embryo in the classes of reptiles, birds and

mammals.

=A-mœ´ba pro´te-us= [Gr. _amoibe_, change; Proteus.] A unicellular

animal; a Protozoan.

=Am-phib´i-a= [Gr. _amphi_, double; _bios_, life.] A class of vertebrates

whose young are fish-like and have gills: the skull has two condyles and

a parasphenoid.

=Am-phi-mix´is= [Gr. _amphi_, double; _mixis_, mingling.]

=Am-phi-ox´us= [Gr. _amphi_, double; _oxys_, sharp.] A small worm-like

vertebrate whose body tapers at both ends. The skeleton is notochordal;

skull, brain, auditory, and renal organs are absent.

=An-ab´o-lism= [Gr. _ana_, up; _ballo_, throw.] Constructive metabolism;

the series of chemical changes by which a cell builds up simple and

stable food into the highly complex and unstable living material.

=An-ap-to-mor´phus= [Gr. _an_-priv.; _hapto_, fasten; _morphe_, shape.]

=An-gi-o-sper´mæ= [Gr. _angeion_, vessel; _sperma_, seed.] Plants whose

seeds are contained in a closed seed-vessel.

=An-nu-la´ta= [Lat. _annulatus_, ringed.] A division of Vermes, including

marine worms, leeches, and earthworms.

=An-the-rid´i-a= [NL., < _anthera_, anther; Gr. dim. _idion_.] The male

sexual organ in cryptogams answering to the anthers in phanerogams.

=An-thro-po-pi-the´cus= [Gr. _anthropos_, man; _pithekos_, ape.]

=An´thro-poid= [Gr. _anthropos_, man; _eidos_, form.] Manlike: said

especially of the gibbons, orangs, gorillas, and chimpanzees.

=An-ti-tox´ine= [Gr. _anti_, opposed to; _toxikon_, poison.]

=A-nu´ra= [Gr. _an_, not; _oura_, tail.] An order of amphibians without a

tail in the adult, including the toads and frogs.

=A´phis= [Gr. _apheideis_, lavish.] In Entomology a genus typical of

Aphididæ. An aphid; a plant-louse.

=Ap-pen´dix ver-mi-for´mis= [Lat. _appendo_, to hang from; _vermis_,

worm; _forma_, form.] A vestigial structure attached to commencement of

the large intestine.

=A-rach´ni-da= [Gr. _arachne_, spider.] A class of Arthropods embracing

the spiders, mites, scorpions, etc.

=Ar-cel´la= [Lat. dim. _arca_, a box.] Belonging to a group of protozoans

having a chitinous shell.

=Ar-chæ´an= [Gr. _archaios_, ancient.] Pertaining to the oldest strata of

rocks in geological history.

=Ar-chæ-op´ter-yx= [Gr. _archaios_, ancient; _pteryx_, bird.] A fossil

bird with reptilian characteristics.

=Ar-che-go-sau´rus= [Gr. _archegos_, beginning; _sauros_, lizard.] A

carboniferous amphibian (labyrinthodont.)

=Ar´go-naut= [Gr. _argo_, swift; _nautes_, sailor.]

=Ar-ma-dil´los= [Sp. dim. of _armado_, armed.] Edentate mammals having a

carapace formed by ossification of the greater part of the skin and the

union of the bony scutes.

=Ar-throp´o-da= [Gr. _arthron_, joint; _pous_, foot.] A branch of animals

(invertebrates) with jointed legs, as insects, spiders, and crabs.

=As´ter= [Gr. _aster_, star.]

=As-ter-oi´de-a= [Gr. _aster_, star; _eidos_, form.] Echinoderms having

radiating arms with ambulacral grooves below, embracing the true

star-fishes.

=At´a-vism= [Lat. _atavus_, grandfather.] Reversion; recurrence to an

ancestral type.

=At´e-les= [Gr. _ateles_, imperfect.]

=Au´ri-cles= [Lat. _auricula_, little ear.] A chamber of the heart which

receives blood from the veins and transmits it to the ventricle.

=A´ves= [Lat. pl. of _avis_, bird.] Birds, a class of vertebrata.

=Ba-cil´lus= [Lat. _bacillum_, a little stick.] A genus of bacteria

consisting of rod-like cells. They multiply by transverse division and by

the formation of endogenous spores. Unicellular plants.

=Bac-te´ri-a= [Gr. _bakterion_, stick.] Microscopic unicellular plants. A

genus of Schizomycetes (fission-fungi).

=Bal-a-no-glos´sus= [Gr. _balanos_, acorn; _glossa_, tongue.] Supposed by

some biologists to belong to the Chordata.

=Beams= [AS. _beam_, tree.] The main stem of a deer’s antler.

=Bel-em´nites= [Gr. _belemnon_, dart.] A belemnitoid cuttlefish.

=Bi´o-phores= [Gr. _bios_, life; _phero_, bear.] Biological units of

hereditary mass.

=Bi´pes= [Lat. _bis_, twice; _pes_, foot.]

=Blas´tid= [Gr. _blastos_, sprout.]

=Blas-to-ge-net´ic= [Gr. _blastos_, a germ; _genesis_, generation.]

Originating in the germ cells.

=Blas´tu-la= [Gr. _blastos_, sprout.] A stage in the growth of

the embryo; a hollow sphere of one layer of cells enclosing a

segmentation-cavity.

=Brach-i-op´o-da= [Lat. _brachium_, arm; Gr. _pous_, foot.] Molluscoid

animals with bivalve shells, one of which is dorsal and the other

ventral; also with brachial appendages coming from the sides of the

mouth. Lamp shells.

=Brach´i-o-pod= [Vid. Brachiopoda.] Lamp shell.

=Bry-oph´y-ta= [Gr. _bryon_, moss; _phyton_, plant.] A division of the

vegetable kingdom consisting of liverworts and mosses.

=Bry-o-zo´a= [Gr. _bryon_, moss; _zoon_, animal.] Moss animals.

=Ca-du-ci-bran-chi-a´ta= [Lat. _caducus_, falling; _branchia_, gills.]

Urodeles that lose their gills before maturity.

=Ca-du-ci-bran´chi-ates= [Vid. Caducibranchiata.]

=Cal´li-thrix= [Gr. _kalos_, beautiful; _thrix_, hair.]

=Cal-a-mo-ich´thys= [Gr. _kalamos_, reed; _ichthys_, fish.]

=Ca´lyx= [Gr. _kalyx_, cover.] The outermost series of leaves (sepals) of

a flower; usually green.

=Cam´bri-an= [_Cambria_, _Wales_.] The name given by Sedgwick to those

Palæozoic rocks that underly the Silurian, in Cambria (or Wales).

=Car-bon-if´er-ous= [Lat. _carbo_, coal; _fero_, bear.]

=Car-i-na´tæ= [Lat. _carinatus_, keel-shaped.] Birds having a keeled

(carinate) breast-bone.

=Car-niv´o-ra= [Lat. _caro_, flesh; _voro_, devour.] Flesh-eating mammals.

=Cas-tra´tion= [Lat. _castratus_.] Removal of the glands that bear the

Germ-Cells.

=Cat-ar-rhi´næ= [Gr. _kata_, down; _rhis_, nose.] Old World monkeys. The

septum of the nose is narrow; the tail is short and not prehensile.

=Cat´ar-rhines= [Vid. Catarrhinæ.] Old World monkeys.

=Ceb´i-dæ= [Gr. _kebos_, long-tailed monkey.] A family of New World

monkeys.

=Ce´bus= [Gr. _kebos_, long-tailed monkey.]

=Cen-o-zo´ic= [Gr. _kainos_, new; _zoe_, life.] Relating to the

Quaternary and Tertiary eras.

=Cen´ti-pede= [Lat. _centum_, hundred; _pes_, foot.] A many jointed

myriapod having a pair of legs to each joint.

=Cen´tro-some= [Gr. _kentron_, center; _soma_, body.] A body just outside

of the nucleus of a cell and that governs the mitotic phases of a cell.

=Ceph-a-lop´o-da= [Gr. _kephale_, head; _pous_, foot.] Molluscs with a

subcentral head, a beaked mouth, and tentacles taking the place of feet,

including cuttlefishes, etc.

=Cer´a-tites= [Gr. _keras_, horn; _ites_, like.] A fossil cephalopod with

the habitation chamber short and sutural saddles mostly simple.

=Cer´a-to-dus= [Gr. _keras_, horn; _odous_, tooth.] So-called from the

horn-like ridges of the teeth. A lung-fish.

=Cer-co-pi-the´ci-dæ= [Gr. _kerkopithekos_, a long-tailed ape; _eidos_

form.] A family of catarrhine anthropoidea.

=Cer-e-bel´lum= [Lat. dim. of _cerebrum_, brain.] A subdivision of the

encephalon.

=Cer´e-brum= [Lat. brain.] A subdivision of the encephalon.

=Cer´e-bral= [Vid. Cerebrum.] Pertaining to the cerebrum.

=Ce-ta´ce-a= [Lat. _cetus_, whale.] An order of fish-like mammals

including the whales and porpoises.

=Chei-rop´te-ra= [Gr. _cheir_, hand; _pteron_, wing.] Including the

Bats,—an order of mammals.

=Chei-ro´tes= [Gr. _cheirotos_, having a hand.] A native lizard of Mexico.

=Che-lo´ni-a= [Gr. _chelone_, tortoise.] An order of reptiles, including

the turtles and tortoises.

=Chi-mæ´roids= [Gr. _chimaira_, a fabled monster; _eidos_, form.] An

order of elasmobranchii (holocephali) with opercular membrane and smooth

skin.

=Chi´ro-mys= [Gr. _cheir_, hand; _mus_, mouse.]

=Chim-pan´zee= [W. Afr.] Anthropopithecus. A West African arboreal,

anthropoid ape; five feet high; distinct eyelashes, eyebrows, and

whiskers; very large ears. It approximates to man in its dentition and

the length of its arms. Has darker hair than gorilla.

=Chi´tin-ous= [Gr. _chiton_, tunic.] Pertaining to chitin, the horny

substance in the skin of insects.

=Chro´ma-tin= [Gr. _croma_, color.] Nuclear threads.

=Chor-da´ta= [Lat. _chorda_, chord.] A subkingdom of animals with a

notochord persistent or evanescent.

=Chro´mo-somes= [Gr. _croma_, color: _soma_, body.] Nuclear threads.

=Chry´so-thrix= [Gr. _chrysos_, gold; _thrix_, hair.]

=Clo-a´ca= [Lat. _cloaca_, a common sewer.] The common cavity into which

the digestive, urinary, and genital canals empty in most vertebrates

below placentals, and in all mammalian embryos.

=Coc´ci= [Gr. _kokkos_, berry.] Pl. of _coccus_. Isolated spherical cells

(bacteria).

=Co-coons´= [F. _cocon_, dim. of _coque_, shell; < Lat. _concha_, shell.]

The protective envelopes spun by certain larval insects, as silkworms, in

which they are inclosed in the chrysalis state.

=Co-do-si´ga um-bel-la´ta= [Gr. _kodon_, a bell; _sige_, silence; Lat.

_umbella_, dim. of _umbra_, shade.]

=Cœ-cil´i-a= [Lat. _cæcus_, blind.] Footless amphibians of snake-like

form; rudimentary eyes; no neck.

=Cœ-len-te-ra´ta= [Gr. _koilos_, hollow; _enteron_, intestine.]

=Cœ-len´ter-ate= [Vid. Cœlenterata.]

=Cϫlome= [Gr. _koilos_, hollow.] The body-cavity of a metazoan between

the viscera and the body-wall.

=Combs= [AS. _camb_, crest or ridge.] The fleshy crests on the heads of

roosters, etc.

=Con-dy-lar´thra= [Gr. _kondylos_, knuckle; _arthron_, joint.] An Eocene

group of ungulates in which the astragalus is not interlocked laterally

with the tibia and its head rounded.

=Co-nif´e-ræ= [Lat. _conus_, cone; _fero_, bear.] The pine family of

trees.

=Co´nus ar-te-ri-o´sus= [_Latin phrase_.] The arterial, cone-shaped

portion of the left ventricle of the heart.

=Co-rol´la= [Lat., dim. of _corona_, crown.] The inner set of leaves

of flowers and usually bright-colored. The individual parts are called

petals.

=Crests= [Lat. _crista_, tuft.] Projecting natural growths on the tops

of animals’ heads and usually ornamental, as the cock’s comb, or the

lengthened feathers of a bird.

=Cre-o-don´ta= [Gr. _kreas_, flesh; _odous_, tooth.] A group of fossil

animals containing forms ancestrally related to existing Carnivora.

=Cre-ta´ceous= [Lat. _creta_, chalk.] Pertaining to the latter part of

the Reptilian age.

=Cri-noi´de-a= [Gr. _krinon_, lily; _eidos_, form.] Stone-lilies; stalked

star-fishes. A division of Echinoderms.

=Cri´noids= [Vid. Crinoidea.]

=Croc-o-dil´i-a= [Lat. _crocodilus_, lizard.] An order of reptiles

including crocodiles, alligators, and gavials. They are the highest order

of reptiles. In them the heart and brain approximate very closely to that

of birds.

=Cros-sop-te-ryg´i-a= [Gr. _krossoi_, tassels; _pterygion_ dim. of

_pteryx_, wing.] A group of fishes with paired, lobate fins, and with an

endodermal skeletal, axis fringed with dermal rays.

=Crus-ta´ce-a= [Lat. _crusta_, crust.] A division of arthropods

containing crabs, lobsters, shrimps, crawfish, barnacles, etc.

=Cryp´to-gams= [Gr. _kryptos_, hidden; _gamos_, marriage.] The lower

of the two great subdivisions of the plant kingdom. They have no true

flowers containing stamens, pistils, and seeds; they propagate by means

of spores.

=Cten-oph´o-ra= [Gr. _kteis_, comb; _phero_, bear.] A subdivision of

cœlenterates with paddle-like locomotive plates arranged in eight

meridional rows on the outer surface of the body.

=Cyc-a-da´ce-æ= [Gr. _kykos_, African coco-palm.] The cycad family of

plants (gymnospermous), of fern-like or palm-like aspect.

=Cys-toi´de-a= [Gr. _kystis_, bladder; _eidos_, form.]

=Cy-no-ceph´a-lus= [Gr. _kyon_, dog; _kephale_, head.]

=Cy´to-plasm= [Gr. _kyo_, be pregnant; _plasma_, < _plasso_, form.]

Protoplasm; especially that portion of a cell apart from the nucleus.

=Dal´ton-ism= [Dalton, chemist, who had color-blindness.]

Color-blindness, especially red-blindness.

=De-cid´u-ate= [Lat. _deciduus_, falling off.] Shed at periodic times.

=Des´mids= [Gr. _desmos_, band.] Unicellular plants of minute size;

bright-green in color; mainly solitary, fresh-water algæ.

=Dev-o´ni-an= [Devonshire, England.] The name given by Murchison to

Palæozoic rocks in Devonshire, England.

=Di´a-toms= [Gr. _dia_, through; _tome_, cutting.] Microscopic

unicellular algæ inhabiting salt or fresh water. Each individual

(frustule) consists of two flint valves which are more or less

symmetrical. They are either isolated or attached together in a series.

=Di-cot-y-le´don-es= [Gr. _dikotylos_, with two hollows.] The most

important and largest class of flowering plants. Characterized by

having seeds with two cotyledons, exogenous stems, and leaves that are

netted-veined; the parts of the flower mostly in fours or fives.

=Di-del´phi-a= [Gr. _di_-, two; _delphys_, womb.] A sub-class of mammals,

as the Marsupials, having a double womb and no placenta.

=Dif-flu´gi-a pyri-form´is= [Lat. _diffluere_, to flow apart; _pyrum_,

pear; _forma_, form.]

=Di-no-sau´ri-a= [Gr. _deinos_, terrible; _sauros_, lizard.] Mesozoic

land reptiles.

=Dip´no-i= [Gr. _di_-, two; _pneo_, breathe.] Fishes with regular gills,

a double or single lung, and nostrils inside as well as outside the

mouth.

=Dro-ma-the´ri-um= [Gr. _dromos_, running; _therion_, small wild beast.]

=Dys-chro-ma-top´si-a= [Gr. _dys_, bad; _chroma_, color; _opsis_, sight.]

Partial color-blindness; difficulty in distinguishing colors.

=E-chi-no-der´ma-ta= [Gr. _echinos_, hedgehog; _derma_, skin.]

=E-chi´no-derms= [Vid. Echinodermata.]

=Ech-i-noi´de-a= [Gr. _echinos_, hedgehog; _eidos_, form.] Echinoderms

including sea urchins.

=Ec´to-derm= [Gr. _ektos_, outside; _derma_, skin.]

=Ec´to-plasm= [Gr. _ektos_, outside; _plasso_, form.]

=E-den-ta´ta= [Lat. _e_, out of; _dens_, tooth.] An order of placentals

with a small, one-lobed cerebrum; without median, cutting teeth:

including armadillos, ant-eaters, and sloths.

=El-as-mo-bran´chi-i= [Gr. _elasmos_, metal plate; _branchia_, gills.]

Fish-like vertebrates which have no membrane bones in the skull or the

shoulder-girdle; five pairs of strap-like gills attached by their distal

ends; claspers to the ventral fins of males; complicated brain with optic

nerves forming a decussation.

=Em´bry-o= [Gr. _en_, in; _bruein_, swell.] The term applied to an animal

in the earlier stages of development.

=Em-bry-ol´o-gy= [Gr. _embryon_, embryo; _logos_, < _lego_, speak.] The

study of embryos.

=En´do-derm= [Gr. _endon_, within; _derma_, skin.]

=En´do-plasm= [Gr. _endon_, within; _plasso_, form.]

=En-ter-op-neus´ta= [Gr. _enteron_, intestine; _pneustos_, breathing.]

Acorn-tongue worms. Smooth-bodied, footless worms, having a large

exserted soft proboscis; breathing by a series of respiratory sacs

opening into the digestive canal, and communicating externally

by spiracles; nervous system situated above a seeming notochord.

Balanoglossus. Included by some biologists among the chordata.

=E-o-hip´pus= [Gr. _eos_. dawn; _hippos_, horse.]

=E´o-cene= [Gr. _eos_, dawn; _kainos_, recent.]

=Ep-en-ceph´a-lon= [Gr. _epi_, upon; _enkephalos_, brain.] A fundamental

subdivision of the brain (encephalon).

=Ep´i-blast= [Gr. _epi_, upon; _blastos_, bud.]

=E´quus= [Lat. horse.]

=E-ryth-ro-lam´prus= [Gr. _erythros_, red; _lampros_, shining.]

=Eu-ca-lyp´tus= [Gr. _eu_, good; _kalypto_, cover.] A large genus of

evergreen trees of the myrtle family.

=Ev-o-lu´tion= [Lat. _e_, out; _volvo_, roll.]

=Ex-o-skel´e-ton= [Gr. _exo_, outside; _skeleton_, dried body.] External

skeleton; bony or horny hardening of the integument.

=Fla-gel´lum= [Lat., dim. of _flagrum_, scourge.] A slender protoplasmic

extension of a cell, for purposes of locomotion.

=Fo-ram-i-nif´e-ra= [Lat. _foramen_, opening; _fero_, bear.] A division

of protozoans secreting a shell perforated by many minute apertures.

=Fos´sil= [Lat. _fodio_, dig.] Any organic body so situated in the earth,

and so buried in solid rock or in earthy deposits, as to be capable of

indefinite preservation.

=Gan´gli-on= [Gr. _ganglion_, tumor.] A swelling that consists of an

aggregation of nerve-cells. It receives and discharges nervous impulses

and serves to stimulate psychical and organic activities.

=Ga-noi´de-i= [Gr. _ganos_, brightness; _eidos_, appearance.]

=Gas-ter-op´o-da= [Gr. _gaster_, stomach; _pous_, foot.] Including all

snails and slugs.

=Gas´tru-la= [Dim. of Lat. _gaster_, stomach.]

=Gem´mæ= [Lat. buds.]

=Geph-y-re´a= [Gr. _gephyra_, bridge.] A division of worms with an

œsophageal nervous ring and ventral chord; no distinct segments or legs;

a terminal or dorsal anus.

=Go´ni-a-tites= [Gr. _gonia_, corner; _lithos_, stone.] A genus of fossil

Ammonites.

=Gor´gets= [Fr. _gorgette_, dim. of _gorge_, throat.] Throat-patches

distinguished by color or texture, especially in humming birds.

=Grap´to-lites= [Gr. _graptos_, written; _lithos_, stone.] Fossil

hydroids.

=Greg-a-ri´na= [Lat. _gregarius_, < _grex_, flock.] A genus typical of

Gregarinidæ. _Gregarina gigantea_ is sixteen millimeters in length and is

one of the largest unicellular animals known.

=Greg-a-rin´i-dæ= [Vid. Gregarina.] More or less elongated amœba-like

Protozoa, having a well-defined cell-wall, and a “subcuticular” system

of muscular fibrillæ; nucleus, but no contractile vacuole; reproduction

by encystment and subdivision of the central cell mass or protoplasm, by

which shelly psorosperms are formed and from which escape the moner-like

young, which undergo a metamorphosis.

=Gro´mi-a o-vi-form´is= [Lat. _gromia_; _ovum_, egg; _forma_, form.] A

characteristic imperforate foraminifer.

=Gym-no-phi´o-na= [Gr. _gymnos_, naked; _ophis_, serpent]

=Gym-no-sper´mæ= [Gr. _gymnos_, naked; _sperma_, seed.] Plants whose

seeds are not contained in a closed seed-vessel, as Cycads and Conifers.

=Hap´a-le= [Gr. _hapalos_, gentle.]

=Ha-pal´i-dæ= [Gr. _hapalos_, gentle] A family of New World monkeys

including the Marmosets.

=Hel-i-co-nid´æ= [N., < _heliconius_, of Helicon; idæ.] A family of

butterflies.

=Hes-per-or´nis= [Gr. _hesperos_, western; _ornis_, bird.] Cretaceous

carinate birds with rudimentary wings, short tail, and pointed teeth

implanted in grooves.

=Hip-po-pot´a-mus= [Gr. _hippos_, horse; _potamos_, river.]

=Hol-o-ceph´a-li= [Gr. _holos_, whole; _kepale_, head.] A subdivision of

Elasmobranchii in which the suspensorium of the lower jaw is continuous

with the cranium, as chimæroids, etc.

=Hol-o-thu-roi´de-a= [Gr. _holos_, whole; _thouros_, rushing.] Worm-like

echinoderms, with skin-like integuments, and circum-oral tentacles;

including sea-cucumbers, sea-slugs, etc.

=Ho-min´i-dæ= [Lat. _homo_, man; idæ.] A family of primates restricted to

mankind.

=Hy´a-lo-plasm= [Gr. _hyalos_, glass; _plasma_, < _plasso_, form.]

=Hy´dra= [Gr. _hydra_, Lernæan serpent, < _hudor_, water.] A fresh-water

polyp, having the form of a cylindrical tube, surrounded at the mouth

with a circle of thread-like tentacles, by which it captures its prey.

=Hy´droid= [Gr. _hudor_, water; _eidos_, form.] Resembling the _hydra_;

pertaining to the Hydroidea.

=Hy-dro-zo´a= [Hydro-; _zoon_, animal.] Cœlenterates including Hydroids

and jelly-fishes.

=Hy-lob-a-ti´næ= [Gr. _hylobates_, one who walks the wood.] An Asiatic

subfamily of apes; the long-armed apes or gibbons.

=Hy-lob´a-tes= [Gr. _hylobates_.] A gibbon,—an Asiatic ape.

=Hy-ra-coi´de-a= [Gr. _hyrax_, shrew-mouse; _eidos_, appearance.]

=Ich-thy-or´nis= [Gr. _ichthys_, fish; _ornis_, bird.] Cretaceous

toothed birds of tern-like form, with socketed acute teeth, and

bi-concave vertebræ

=Ich-thy-o-sau´ri-a= [Gr. _ichthys_, fish; _sauros_, lizard.]

=Id´i-o-blast= [Gr. _idios_, individual; _blastema_, sprout.]

=In-fu-so´ri-a= [Lat. _in_, into; _fundo_, pour.] So called because

including many animalcules that occur in infusions of decaying substances.

=In-sec´ta= [Lat. _in_, into; _seco_, cut.]

=In-sec-tiv´o-ra= [Lat. _insectum_, insect; _voro_, devour.]

=In-ver-te-bra´ta= [Lat. _in_, not; _vertebratus_, jointed.] Including

all animals that do not possess a notochord or backbone: opposed to

Vertebrata.

=In-ver´te-brates= [Vid. Invertebrata.]

=Ju-ras´sic= [Jura mountains.]

=Kaf´ir-boom= [Erythrina caffra.] A prickly-stemmed tree of South Africa.

=Kal´li-ma para-lek´ta= [Gr. _kallimos_, beautiful; _para_, along side

of; _lektos_, picked out.]

=Keri-vou´la pic´ta.=

=Lab-y-rin´tho-donts= [Gr. _labyrinthos_, labyrinth; _odous_, tooth.]

Extinct amphibians.

=Lac-er-til´i-a= [Lat. _lacertus_, lizard.]

=La-ge´na= [Gr. _lagynos_, flask.]

=La-mel-li-bran-chi-a´ta= [Lat. _lamella_, a plate; _branchia_, gills.]

Bivalve molluscs.

=La-nu´go= [Lat. _lana_, wool.]

=Lar´væ= [Lat. pl. of _larva_, mask.] The early forms of animals when

they are unlike the parent. In insects the first stages after leaving the

eggs, preceding the pupa, as maggots or caterpillars.

=Lem-u-roi´de-a= [Lemur; Gr. _eidos_, appearance.] A sub order of

Primates. Prosimiæ.

=Lep-i-do-si´ren= [Gr. _lepis_, scale; _siren_, a genus of amphibians.]

One of the lung-fishes.

=Lep-to-car´di-i= [Gr. _leptos_, fine, small; _kardia_, heart.]

=Liv´er-worts.=

=Lon-gi-cor´ni-a= [Lat. _longus_, long; _cornu_, horn.] A division of

beetles having very long filiform antennæ.

=Ma-caques´= [F., < Afr. _macaquo_.] Cercopithecine monkeys of the genus

_macacus_. Their form is stout; large ischial tuberosities: muzzle

considerably produced.

=Ma-ca´cus.=

=Mam´mal= [Lat. _mamma_, breast; suffix -_al_; in analogy with

Animal. Dr. Th. Gill.] Vertebrate animal whose female has mammæ, or

milk-secreting organs.

=Mam-ma´li-a= [Vid. mammal.]

=Man´tis= [Gr. _mantis_, prophet.] The mantises are insects noted for the

manner in which they carry the large spinous fore legs when waiting for

prey. They have the attitude, then, as if praying.

=Mar´mo-set.= A small South-American monkey.

=Mar-si-po-bran´chi-i= [Gr. _marsipos_, bag; _branchia_, gills.]

=Mar-su´pi-al= [Lat. _marsupium_, pouch.] Animals having a marsupium or

pouch for retaining the young.

=Mas´to-don= [Gr. _mastos_, breast; _odous_, tooth.] An extinct elephant.

=Me-dul´la= [Lat. _medius_, middle.] A subdivision of the brain—that

portion especially that is continuous with the spinal chord.

=Men-o-bran´chus= [Gr. _meno_, remain; _branchia_, gills.] A large

American aquatic amphibian, of salamander-like form, with persistent

gills, as the mud-puppy.

=Mens sana in corpore sano.= A Latin phrase meaning a sound mind in a

sound body.

=Mes-en-ceph´a-lon= [Gr. _mesos_, middle; _enkephalos_, brain.] A

fundamental segment of the brain.

=Mes´en-chyme= [Gr. _mesos_, middle; _enchyma_, infusion.]

=Mes´o-blast= [Gr. _mesos_, middle; _blastos_, germ.]

=Mes-o-glϫa= [Gr. _mesos_, middle; _gloia_, glue.]

=Mes-o-hip´pus= [Gr. _mesos_, middle; _hippos_, horse.]

=Mes-o-zo´ic= [Gr. _mesos_, middle; _zoe_, life.]

=Met-a-dis-coi´dal= [Gr. _meta_, after; _diskos_, disk; _eidos_,

appearance.] Resembling a discoidal form.

=Met-a-mor´pho-sis= [Gr. _meta_, over; _morphe_, form.] The series of

pronounced external changes through which an animal passes after leaving

the egg-envelopes and before reaching sexual maturity.

=Met-a-phy´ta= [Gr. _meta_, above, higher; _phyton_, plant.]

=Met´a-plasm= [Gr. _metaplasmos_, transformation.]

=Met-a-zo´a= [Gr. _meta_, after, higher; _zoon_, animal.]

=Met-en-ceph´a-lon= [Gr. _meta_, after; _enkephalos_, brain.] A

fundamental segment of the brain.

=Mi-cro-ceph-a´li-a= [Gr. _mikrokephalos_, small-headed.] Imperfect

development of the cranium.

=Mi-cren-ceph-a´li-a= [Gr. _mikros_, small; _enkephalos_, brain.]

Small-brained.

=Mi´cro-cosm= [Gr. _mikros_, small; _kosmos_, world.]

=Micro-gro´mi-a so-ci-al´is= [Gr. _mikros_, small; _gromia_; Lat.

_socialis_ < _socius_, companion.]

=Mi-cro-les´tes.=

=Mi´das.= A wealthy king of Phrygia.

=Mi-o-hip´pus= [Miocene; Gr. _hippos_, horse.]

=Mi´o-cene= [Gr. _meion_, less; _kainos_, recent.]

=Mi-to´sis= [Gr. _mitos_, thread.]

=Mol-lus´ca= [Lat. _mollis_, soft.]

=Mon-o-cot-y-le´don-es= [Gr. _monos_, single; _kotyledon_, cup-shaped

cavity.] A group of flowering plants in which the first leaves of

the embryo are alternate, for which reason they are said to have one

seed-leaf or cotyledon.

=Mon-o-del´phi-a= [Gr. _monos_, single; _delphys_, womb.] A sub-class of

mammals having a single vagina and uterus; embryo attached by a placenta;

brain has a corpus callosum. Includes all animals above Monotremes and

Marsupials.

=Mon´o-tremes= [Gr. _monos_, single; _trema_, hole.] An order of

ornithodelphians.

=Mor´u-la= [Lat. dim. of _morum_, mulberry.]

=Mul-ti-tu-ber-cu-la´ta= [Lat. _multus_, many; _tuberculum_, tubercle.]

=My-ce´tes= [Gr. _myketes_, bellower.]

=Myr-i-ap´o-da= [Gr. _myrios_, numberless; _pous_, foot.] Insects with

numerous pairs of legs, as centipedes.

=Nau´ti-loids= [Gr. _nautilos_, sailor; _eidos_, like.] A group of

cephalopods.

=Nau´ti-lus= [Gr. _nautilos_, sailor.] A cephalopod.

=Nem-a-thel-min´thes= [Gr. _nema_, thread; _helmins_, worm.]

=Nem-er-ti´na= [Gr. _nemertes_, unerring.] Worms with skin ciliated,

proboscis retractile, and nervous, muscular, and vascular systems

characteristically developed.

=Ne-o-lith´ic= [Gr. _neos_, new; _lithos_, stone.]

=Noc-ti-lu´ca mi-li-a´ris= [Lat. _nox_, night; _luceo_, shine;

_miliarius_, < _milium_, millet.]

=No´to-chord= [Gr. _notos_, the back; _chorda_, a chord.] A cartilaginous

rod found in the young chordate embryo in a situation that is later

on occupied by the centers of the bodies of the vertebræ. It separates

a dorsal nervous system from a ventral alimentary (digestive) canal.

The notochord is persistent in its entirety in Leptocardians and

Marsipobranchs and also in some pisces, as the sturgeon.

=O-don-tor´ni-thes= [Gr. _odous_, a tooth; _ornis_, bird.] Including all

those extinct birds having teeth.

=Œ-soph´a-gus= [Gr. _oiso_, will bear; _phagein_, eat.] The gullet; the

membranous tube through which food passes from the pharynx to the stomach.

=On-tog´e-ny= [Gr. _on_, being; _genesis_, origin.] The history of the

evolution of the individual; the development of the individual.

=On-to-ge-net´ic= [Gr. _on_, being; _genesis_, origin.] Pertaining to

ontogeny.

=On-y-choph´o-ra= [Gr. _onyx_, claw; _pherein_, bear.] Arthropods

including only a single genus, the curious caterpillar-like Peripatus.

=Oösperm= [Gr. _oon_, egg; _sperma_, semen.] A fertilized ovum. The first

stage in the existence of a human being is called oösperm.

=O-per´cu-lum= [Lat. lid.] The gill-cover.

=O-phid´i-a= [Gr. _ophis_, serpent.] Serpents; snakes.

=Op-po´nens Hal-lu´cis= [Lat. _ob_, _pono_, to place over against;

_hallux_, great toe.] The name of a muscle in the foot.

=Or-do-vi´cian= [_ordovices_, ancient Celtic tribe in Wales.]

=Or-nith-o-del´phi-a= [Gr. _ornis_, bird; _delphys_, womb.] A sub-class

of oviparous mammals.

=Or-o-hip´pus= [Gr. _oros_, mountain; _hippos_, horse.]

=Or-tho-cer´a-tites= [Gr. _orthos_, straight; _keras_, horn.]

=Os´te-o-blasts= [Gr. _osteon_, bone; _blastano_, sprout.]

=Os´te-o-clasts= [Gr. _osteon_, bone; _klao_, destroy.]

=Os´tra-co-derms= [Gr. _ostrakon_, shell; _derma_, skin.]

=Ovum= [Lat. _egg_.] Female germ-cell; female, encysted, sexual cell.

=O-vip´a-rous= [Lat. _ovum_, egg; _pairo_, produce.] Producing eggs that

mature and are hatched outside the body.

=Pal´li-um= [Gr. _mantle_.]

=Pa-læ-o-lith´ic= [Gr. _palaios_, ancient; _lithos_, stone.]

=Pa-læ-o-zo´ic= [Gr. _palaios_, ancient; _zoe_, life.]

=Pan-do-ri´na mor´um= [Gr. Pandora; _moron_, mulberry.]

=Pan-gen´e-sis= [Gr. _pas_, all; _genesis_, origin.]

=Par-a-me´ci-um= [Gr. _paramekes_, of longish shape.]

=Par-then-o-gen´e-sis= [Gr. _parthenos_, virgin; _genesis_, origin.]

Production of a new individual from a virgin female without intervention

of a male; reproduction by means of unfertilized eggs.

=Per-en-ni-bran-chi-a´ta= [Lat. _perennis_, perpetual; _branchia_, gills.]

=Per-en-ni-bran´chi-ates= [Vid. Perennibranchiata.]

=Ped´al= [Lat. _pes_, foot.]

=Per´mi-an= [Perm, Russia.]

=Phan´er-o-gams= [Gr. _phaneros_, visible; _gamos_, marriage.] Flowering

plants.

=Phos-phor-es´cence.=

=Phryn-o-ceph´a-lus mys-ta´ce-us.=

=Phy-log´e-ny= [Gr. _phylon_, tribe; _genesis_, origin.] The history of

the evolution of a species or group; distinguished from ontogeny.

=Phy-lo-ge-net´ic= [Vid. phylogeny.] Pertaining to phylogeny.

=Pith´e-coid= [Gr. _pithekos_, ape; _eidos_, like.]

=Pith-e-can-thro´pus= [Gr. _pithekos_, ape; _anthropos_, man.]

=Pla-gi-os´to-mi= [Gr. _plagios_, oblique; _stoma_, mouth.] A division of

Elasmobranchii, including sharks and rays.

=Pla-cen´tal= [Lat. _placenta_, cake.] So called on account of its

shape. Pertaining to the _placenta_, the organ of attachment of higher

vertebrate (monodelph) embryos to the wall of the uterus of the female.

=Plas´tids= [Gr. _plastos_, formed.]

=Plat-y-hel-min´thes= [Gr. _platys_, flat; _helminos_, worm.]

=Plat-y-rhi´næ= [Gr. _platys_, broad, flat; _rhis_, nose.] Monkeys of the

New World having long tails and a wide septum to the nose.

=Pleur-a-can´thus= [Gr. _pleuron_, rib; _akantha_, thorn.]

=Pleu´ral= [Gr. _pleura_, rib, side.]

=Pli-o-hip´pus= [Pliocene; Gr. _hippos_, horse.]

=Pli´o-cene= [Gr. _pleion_, more; _kainos_, recent.]

=Plumes= [Lat. _pluma_, small soft feather.] Feathers, especially when

ornamental or large; or tufts of large and ornamental feathers.

=Pneu-mo-coc´ci= [Gr. _pneumon_, lung; _kokkos_, berry.] Bacteria

(spheroidal) found in those suffering from pneumonia.

=Pol-y-dac´tyl-ism= [Gr. _polys_, many; _daktylos_, finger, toe.] The

possession of an abnormally large number of fingers or toes.

=Pol-y-mor´phism= [Gr. _polys_, many; _morphe_, form.] Exhibition by a

group of animals, as a species, of different types of form or structure.

=Po-lyp´te-rus= [Gr. _polypteros_, many-winged.]

=Po-ly´o-don= [Gr. _polys_, many; _odous_, tooth.]

=Pol´yp= [Gr. _polys_, many; _pous_, foot.]

=Pol´y-the-ism= [Gr. _polys_, many; _theos_, god.]

=Po-rif´e-ra= [Lat. _porus_, pore; _fero_, bear.]

=Pre-Pa-læ-o-lith´ic= [Lat. _præ_, before; Palæolithic.] The period of

time preceding the Ancient Stone Age.

=Pri-ma´tes= [Lat. _primus_, first.] An order of mammals.

=Pro-bos-cid´e-a= [Gr. _pro_, before; _bosko_, feed.]

=Pro-nu´cle-us= [Lat. _pro_, before; _nucleus_, kernel.]

=Pros-en-ceph´a-lon= [Gr. _pro_, before; _enkephalos_, brain.] A

fundamental segment of the brain.

=Pro-to-hip´pus= [Gr. _protos_, first; _hippos_, horse.]

=Pro-toph´y-ta= [Gr. _protos_, first; _phyton_, plant.]

=Pro´to-plasm= [Gr. _protos_, first; _plasma_, < _plasso_, form.]

=Pro-top´te-rus= [Gr. _protos_, first; _pteron_, wing.]

=Pro-to-zo´a= [Gr. _protos_, first; _zoon_, animal.]

=Pseu-do-he-red´i-ty= [Gr. _pseudes_, false; Lat. _heredita_, heirship.]

=Pseu-do-po´di-a= [Gr. _pseudes_, false; _pous_, foot.]

=Psy-cho-zo´ic= [Gr. _psyche_, soul; _zoe_, life.]