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WORLD'S FAMOUS BOOKS 



The Descent of Man 

And Selection in Relation to Sex 



By 

Charles Darwin 

Revised Edition 



Illustrated 



New York and London 
MERRILL AND BAKER 

Publishers 






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PREFACE TO THE SECOND EDITION. 



During the successive reprints of tlie first edition of this work, 
published in 1871, I was able to introduce several important cor- 
rections; and now that more time has elapsed, I have endeavored 
to profit by the fiery ordeal through which the book has passed, 
and have taken advantage of all the criticisms which seem to me 
sound. I am also greatly indebted to a large number of corre- 
spondents for the communication of a surprising number of new 
facts and remarks. These have been so numerous, that I have 
been able to use only the more important ones; and of these, as 
well as of the more important corrections, I will append a list. 
Some new illustrations have been introduced, and four of the old 
drawings have been replaced by better ones, done from life by 
Mr. T. W. Wood. I must especially call attention to some observa- 
tions which I owe to the kindness of Prof. Huxley (given as a sup- 
plement at the end of Part I.), on the nature of the differences be- 
tween the brains of man and the higher apes. I have been par- 
ticularly glad to give these observations, because during the last 
few years several memoirs on the subject have appeared on the 
Continent, and their importance has been, in some cases, greatly 
exaggerated by popular writers. 

I may take this opportunity of remarking that my 
critics frequently assume that I attribute all changes of 
corporeal structure and mental power exclusively to the 
natural selection of such variations as are often called 
spontaneous; whereas, even in the first edition of the 'Origin 
of Species,' I distinctly stated that great weight must 
be attributed to the inherited effects of use and disuse, with 
respect both to the body and mind. I also attributed some amount 
of modification to the direct and prolonged action of changed con- 
ditions of life. Some allowance, too, must be made for occasional 
reversions of structure; nor must we forget what I have called 
"correlated" growth, meaning, thereby, that various parts of the 
organization are in some unknown manner so connected, that 
when one part varies, so do others; and if variations in the one 



Vi PREFACE TO THE SECOND EDITION. 

are accumulated by selection, other parts will be modified. Again, 
it has been said by several critics, that when I found that many 
details of structure in man could not be explained through natural 
selection, I invented sexual selection; I gave, however, a tolerably 
clear sketch of this principle in the first edition of the 'Origin of 
Species,' and I there stated that it was applicable to man. This 
subject of sexual selection has been treated at full length in the 
present work, simply because an opportunity was here first afforded 
me. I have been struck with the likeness of many of the half- 
favorable criticisms on sexual selection, with those which ap- 
peared at first on natural selection; such as, that it would explain 
some few details, but certainly was not applicable to the extent 
to which I have employed it. My conviction of the power of sexual 
selection remains unshaken; but it is probable, or almost certain, 
that several of my conclusions will hereafter be found erroneous; 
this can hardly fail to be the case in the first treatment of a sub- 
ject. When naturalists have become familiar with the idea of 
sexual selection, it will, as I believe, be much more largely ac- 
cepted; and it has already been fully and favorably received by 
several capable judges. 

Down, Beckenham, Kent, 
September, 1874. 



CONTENTS. 



Introduction Pages 1-A 



PART I. 
THE DESCENT OR ORIGIN OP MAN. 



■j CHAPTER I. 

THE EVIDENCE OF THE DESCENT OF MAN FROM SOME 

LOWER FORM. 

Nature of the evidence bearing on the origin of man — Homologous 
structures in man and the lower animals — Miscellaneous points 
of correspondence— Development — Rudimentary structures, mus- 
cles, sense-organs, hair, hones, reproductive organs, &c. — The 
bearing of these three great classes of facts on the origin of man 



• CHAPTER II. 

ON THE MANNER OF DEVELOPMENT OF MAN FROM 
SOME LOWER FORM. 

Variability of body and mind in man — Inheritance — Causes of 
variability— Laws of variation the same in man as in the lower 
animals — Direct action of the conditions of life — Effects of the in- 
creased use and disuse of parts— Arrested development— Rever- 
sion — Correlated variation — Rate of increase— Checks to increase 
— Natural selection— Man the most dominant animal in the world 
— Importance of his corporeal structure — The causes which have 
led to his becoming erect — Consequent changes of structure — De- 
crease in size of the canine teeth — Increased size and altered 
shape of the skull — ^Nakedness — Absence of a tail— Defenseless 

condition of man 25 

vii 



Viij CONTENTS. 

CHAPTER III. 

COMPARISON OF THE MENTAL. POWERS OF MAN AND 
THE LOWER ANIMALS. 

The difference in mental power between the highest ape and the 
lowest savag-e, immense— Certain instincts in common— The emo- 
tions—Curiosity—Imitation—Attention—Memory — Imagination- 
Reason— Progressive improvement— Tools and weapons used by 
animals— Abstraction, Self-consciousness— Language— Sense of 
beauty— Belief in God, spiritual agencies, superstitions 88 



CHAPTER IV. 

COMPARISON OF THE MENTAL POWERS OP MAN AND 
THE LOWER ANIMALS— Continued. 

The moral sense— Fundamental proposition— The qualities of so- 
cial animals— Origin of sociability— Struggle between opposed in- 
stincts—Man a social animal— the more enduring social instincts 
conquer other less persistent instincts— The social virtues alone 
regarded by savages— The self-regarding virtues acquired at a 
later stage of development— The importance of the judgment of 
the members of the same community on conduct— Transmission 
of moral tendencies— Summary 



CHAPTER V. 

ON THE DEVELOPMENT OF THE INTELLECTUAL. AND 
MORAL FACULTIES DURING PRIMEVAL AND CIVIL- 
IZED TIMES. 

Advancement of the intellectual powers through natural selec- 
tion—Importance of imitation— Social and moral faculties— Their 
development within the limits of the same tribe— Natural selec- 
tion a-s affecting civilized nations— Evidence that civilized na- 
tions were once barbarous 124 



chapteh vl 

ON THE AFFINITIES AND GENEALOGY OF MAN. 

Position of man in the animal series— The natural system genea- 
logical—Adaptive characters of slight value— Various small points 
of resemblance between man and the Quadrumana— Rank of 
man in the natural system— Birthplace and antiquity of man- 
Absence of fossil connecting-links— Lower stages in the geneal- 
ogy of man, as inferred, firstly from his affinities and secondly 
from his structure— Early androgynous condition of the Verte- 
brata— Conclusion 142 



CONTENTS. ix 

CHAPTER VII. 

ON THE RACES OF MAN. 

The nature and value of specific characters— Application to the 
races of man — ^Arguments in favor of, and opposed to, ranking 
the so-called races of man as distinct species — Sub-species — Mon- 
og-enists and polygenists— Convergence of character — Numerous 
points of resemblance in body and mind between the most dis- 
tinct races of man — The state of man when he first spread over 
the earth — Each race not descended from a single pair — The ex- 
tinction of races— The formation of races — The effects of crossing 
— Slight influence of the direct action of the conditions of life- 
Slight or no influence of natural selection— Sexual selection 162 



PART II. 
SEXUAL SELECTION. 



CHAPTER VIII. 

PRINCIPLES OF SEXUAL SELECTION. 

Secondary sexual characters— Sexual selection— Manner of action 
—Excess of males— Polygamy — The male alone generally modified 
through sexual selection— Eagerness of the male — Variability of 
the male — Choice exerted by the female — Sexual compared with 
natural selection — Inheritance at corresponding periods of life, 
at corresponding seasons of the year, and as limited by sex— Re- 
lations between the several forms of inheritance — Causes why one 
sex and the young are not modified through sexual selection — 
Supplement on the proportional numbers of the two sexes 
throughout the animal kingdom— The proportion of the sexes in 
relation to natural selection 203 



CHAPTER IX. 

SECONDARY SEXUAL CHARACTERS IN THE LOWER 
CLASSES OF THE ANIMAL KINGDOM. 

These characters absent in the lowest classes— Brilliant colors — 
Mollusca— Annelids — Crustacea, secondary sexual characters 
strongly developed; dimorphism; color; characters not acquired 
before maturity— Spiders, sexual colors of; stridulation by the 
males— Myriapoda 257 



CHAPTER X. 

SECONDARY SEXUAL CHARACTERS OF INSECTS. 

Diversified structures possessed by the males for seizing the fe- 
males—Differences between the sexes, of which the meaning is 



3j CONTENTS. 

Page 

not understood— Difference in size between the sexes— Thysanura 
— Diptera— Hemiptera— Homoptera, musical powers possessed by 
the males alone— Orthoptera, musical instruments of the males, 
much diversified in structure; pugnacity; colors— NeuVoptera sex- 
ual differences in color— Hymenoptera, pugnacity and colors— 
Coleoptera, colors; furnished with great horns, apparently as an 
ornament; battles; stridulating organs generally common to both 
sexes • 



272 



CHAPTER XI. 

INSECTS, continued.— ORDER LEPIDOPTERA. 
(Butterflies and moths.) 

Courtship of butterflies— Battles— Ticking noise— Colors common to 
both sexes, or more brilliant in the males— Examples— Not due to 
the direct action of the conditions of life— Colors adapted for pro- 
tection—Colors of moths— Display— Perceptive powers of the Lep- 
idoptera— Variability— Causes of the difference in color between 
the males and females— Mimicry, female butterflies more bril- 
liantly colored than th'e males— Bright colors of caterpillars- 
Summary and concluding remarks on the secondary sexual char- 
acters of insects— Birds and insects compared 304 



CHAPTER XII. 

SECONDARY SEXUAL, CHARACTERS OF FISHES, AMPHIB- 
IANS, AND REPTILES. 

Fishes: Courtship and battles of the males— Larger size of the 
females— Males, bright colors and ornamental appendages; other 
strange characters— Colors and appendages acquired by the males 
during the breeding-season alone— Fishes with both sexes bril- 
liantly colored— Protective colors— The less conspicuous colors 
of the female cannot be accounted for on the principle of protec- 
tion—Male fishes building nests, and taking charge of the ova and 
young. Amphibians: Differences in structure and color between 
the sexes— Vocal organs. Reptiles: Chelonians— Crocodiles- 
Snakes, colors in some cases protective— Lizards, battles of— Or- 
namental appendages— Strange differences in structure between 
the sexes— Colors— Sexual differences almost as great as with 
birds 321 



CHAPTER XIII. 

'SECONDARY SEXUAL, CHARACTERS OP BIRDS. 

Sexual differences— Law of battle— Special weapons— Vocal organs 
— Instrumental music— Love-antics and dances— Decorations, per- 
manent and seasonal— Double and single annual moults — Display 
of ornaments by the males 355 



CONTENTS. Xi 

Page 
CHAPTER XIV. 

BIRDS.— Continued. 

Choice exerted by the female — Length of courtship— Unpaired birds 
— Mental qualities and taste for the beautiful — Preference or an- 
tipathy shown by the female for particular males — Variability of 
birds — Variations sometimes abrupt — Laws of variation — Forma- 
tion of ocelli — Gradations of character — Case of Peacock, Argus 
pheasant and Urosticte 399 



CHAPTER XV. 

BIRDS.— Continued. 

Discussion as to why the males alone of some species, and both 
sexes of others are brightly colored — On sexually-limited inherit- 
ance, as applied to various structures and to brightly-colored 
plumage — Nidification in relation to color — Loss of nuptual plum- 
age during the winter , 438 



CHAPTER XVI. 

BIRDS.— Concluded. 

The immature plumage in relation to the character of the plum- 
age in both sexes when adult — Six classes of cases — Sexual differ- 
ences between the males of closely-allied or representative spe- 
cies — The female assuming the characters of the male — Plumage 
of the young in relation to the summer and winter plumage of 
the adults — On the increase of beauty in the birds of the world — 
Protective coloring — Conspicuously-colored birds— Novelty appre- 
ciated—Summary of the four chapters on birds 458 



CHAPTER XVII. 

SECONDARY SEXUAL CHARACTERS OF MAMMALS. 

The law of battle — Special weapons, confined to the males— Cause 
of absence of weapons in the female — Weapons common to both 
sexes, yet primarily acquired by the male — Other uses of such 
weapons — Their high importance — Greater size of the male — 
Means of defense — On the preference shown by either sex in the 
pairing of quadrupeds 496 



CHAPTER XVIII. 

SECONDARY SEXUAL CHARACTERS OP MAMMALS— Con- 
tinued. 

Voice— Remarkable sexual peculiarities in seals— Odor— Develop- 
ment of the hair — Color of the hair and skin— Anomalous case of 
the female being more ornamented than the male — Color and or- 



Xii CONTENTS. 

Page 
naments due to sexual selection— Color acquired for the sake of 
protection— Color, though common to both sexes, often due to 
sexual selection— On the disappearance of spots and stripes in 
adult quadrupeds — On the colors and ornaments of the Quadru- 
mana— Summary 521 



PART III. 



SEXUAL SELECTION IN RELATION TO MAN, 
AND CONCLUSION. 

-^ CHAPTER XIX. 
SECONDARY SEXUAL CHARACTERS OF MAN. 

Differences between man and woman— Causes of such differences, 
and of certain characters common to both sexes— Law of battle 

- —Differences in mental powers, and voice— On the influence of 
beauty in determining the marriages of mankind— Attention paid 
by savages to ornaments— Their ideas of beauty in woman— The 
tendency to exaggerate each natural peculiarity 551 



i CHAPTER XX. 

SECONDARY SEXUAL CHARACTERS OF MAN.— Continued. 

On the effects of the continued selection of women according to a 
different standard of beauty in each race— On the causes which 
interfere with sexual selection in civilized and savage nations — 
Conditions favorable to sexual selection during primeval times— 
On the manner of action of sexual selection with mankind — On 
the women in savage tribes having some power to choose their 
husbands— Absence of hair on the body, and development of the 
beard— Color of the skin— Summary 580 



^^ CHAPTER XXI. 

GENERAL SUMMARY AND CONCLUSION. 

Main conclusion that man is descended from some lower form- 
Manner of development— Genealogy of man— Intellectual and 
moral faculties— Sexual selection— Concluding remarks 601 

Index 615 



THE DESCENT OF MAN; 



AND 



SELECTION IN RELATION TO SEX. 



INTRODUCTION. 

The nature of the following work will be best understood by a 
brief account of how it came to be written. During many years 
I collected notes on the origin or descent of man, without any 
intention of publishing on the subject, but rather with the de- 
termination not to publish, as I thought that I should thus only 
add to the prejudices against my views. It seemed to me sufla- 
cient to indicate, in the first edition of my 'Origin of Species,' that 
by this work "light would be thrown on the origin of man and 
"his history;" and this implies that man must be included with 
other organic beings in any general conclusion respecting his 
manner of appearance on this earth. Now the case wears a 
wholly different aspect. When a naturalist like Carl Vogt ven- 
tures to say in his address as President of the National Institution 
of Geneva (1869), "personne, en Europe au moins, n'ose plus sou- 
"tenir la creation independante et de toutes pieces, des especes," 
it is manifest that at least a large number of naturalists must ad- 
mit that species are the modified descendants of other species; 
and this especially holds good with the younger and rising natural- 
ists. The greater number accept the agency of natural selection; 
though some urge, whether with justice the future must decide, 
that I have greatly overrated its importance. Of the older and 
honored chiefs in natural science, many unfortunately are still 
opposed to evolution in every form. 

In consequence of the views now adopted by most naturalists, 
and which will ultimately, as in every other case, be followed by 
others who are not scientific, I have been led to put together my 
notes, so as to see how far the general conclusions arrived at in 
my former works were applicable to man. This seemed all the 
more desirable, as I had never deliberately applied these views to 
a species taken singly. When we confine our attention to any 
one form, we are deprived of the weighty arguments derived from 
2 



2 INTRODUCTION. 

tlie nature of the affinities which connect together v/hole groups 
of organisms — their geographical distribution in past and present 
times, and their geological succession. The homological struc- 
ture, embryological development, and rudimentary organs of a 
species remain to be considered, whether it be man or any other 
animal, to which our attention may be directed; but these great 
classes of facts afford, as it appears to me, ample and conclusive 
evidence in favor of the principle of gradual evolution. The 
strong support derived from the other arguments should, however, 
always be kept before the mind. 

The sole object of this work is to consider, firstly, whether 
man, like every other species, is descended from some pre-exist- 
ing form; secondly, the manner of his development; and thirdly, 
the value of the differences between the so-called races of man. 
As I shall confine mj'^self to these points, it will not be necessary 
to describe in detail the differences between the several races — an 
enormous subject which has been fully discussed in many valu- 
able works. The high antiquity of man has recently been demon- 
strated by the labors of a host of eminent men, beginning with 
M. Boucher de Perthes; and this is the indispensable basis for 
understanding his origin. I shall, therefore, take this conclusion 
for granted, and may refer my readers to the admirable treatises 
of Sir Charles Lyell, Sir John Lubbock, and others. Nor shall 
I have occasion to do more than to allude to the amount of differ- 
ence between man and the anthropomorphous apes; for Prof. 
Huxley, in the opinion of most competent judges, has conclusively 
shown that in every visible character man differs less from the 
higher apes, than these do from the lower members of the same 
order of Primates. 

This work contains hardly any original facts in regard to man; 
but as the conclusions at which I arrived, after drawing up a 
rough draft, appeared to me interesting, I thought that they might 
interest others. It has often and confidently been asserted, that 
man's origin can never be known: but ignorance more frequently 
begets confidence than does knowledge: it is those who know lit- 
tle, and not those who know much, who so positively assert that 
this or that problem will never be solved by science. The con- 
clusion that man is the co-descendant with other species of some 
ancient, lower, and extinct form, is not in any degree new. La- 
marck long ago came to this conclusion, which has lately been 
maintained by several eminent naturalists and philosophers; for 
instance, by Wallace, Huxley, Lyell, Vogt, Lubbock, Biichner, 
Rolle, &c.,^ and especially by Hackel. This last naturalist, besides 

1 As the works of the first-named authors are so well known, I need 
not give the titles; but as those of the latter are less well known in 
Eng-land, I will give them :— 'Sechs Vorlesungen uber die Darwin'sche 



INTRODUCTION. 3 

Ms great work, 'Generelle Morphologie' (1866), has recently (1868, 
with a second edit, in 1870), published his 'Natiirliche Schop- 
fungsgeschichte,' in which he fully discusses the genealogy of 
man. If this work had appeared before my essay had been writ- 
ten, I should probably never have completed it. Almost all the 
conclusions at which I have arrived I find confirmed by this natur- 
alist, whose knowledge on many points is much fuller than mine. 
V/herever I have added any fact or view from Prof. Hackel's 
writings, I give his authority in the text; other statements I 
leave as they originally stood in my manuscript, occasionally giv- 
ing in the foot-notes references to his workfe, as a confirmation of 
the more doubtful or interesting points. 

During many years it has seemed to me highly probable that 
sexual selection has played an important part in differentiating 
the races of man; but in ray 'Origin of Species' (first edition, p. 
199) I contented myself by merely alluding to this belief. When 
I came to apply this view to man, I found it indispensable to treat 
the whole subject in full detail.- Consequently the second part of 
the present work, treating of sexual selection, has extended to an 
inordinate length, compared with the first part; but this could not 
be avoided. 

I had intended adding to the present volumes an essay on the 
expression of the various emotions by man and the lower animals. 
My attention was called to this subject many years ago by Sir 
Charles Bell's admirable work. This illustrious anatomist main- 
tains that man is endowed with certain muscles solely for the 
sake of expressing his emotions. As this view is obviously op- 
posed to the belief that man is descended from some other and 
lower form, it was necessary for me to consider it. I likewise 
wished to ascertain how far the emotions are expressed in the 
same manner by the different races of man. But owing to the 
length of the present work, I have thought it better to reserve my 
essay for separate publication. 



Theorie:' zweite Auflage, 1868, von Dr. L. Buchner; translated into 
French under the title 'Conferences sur la Theorie Darwinienne,' 1869, 
'Der Mensch, im Lichte der Darwin' sche Lehre,' 1865, von Dr. F. 
Rolle. I will not attempt to give references to all the authors who have 
taken the same side of the question. Thus G. Canestrini has published 
CAnnuario della Soc. d. Nat.,' Modena, 1867, p. 81) a very curious 
paper on rudimentary characters, as bearing on the origin of maji. 
Another work has (1869) been published by Dr. Francesco Barrage, 
bearing in Italian the title of "Man made in the image of God, was 
"also made in the image of the ape." 

2 Prof. Hackel was the only author who, at the time when this work 
first appeared, had discussed the subject of sexual selection, and had 
seen its full importance, since the publication of the 'Origin' ; and this 
iie did in a very able manner in his various works. 



PART I. 

THE DESCENT OR ORIGIN OF MAN. 



CHAPTER I. 



THE EVIDENCE OF THE DESCENT OF MAN FROM 
SOME LOWER FORM. 

Nature of the evidence bearing on the origin of man— Homologous 
structures in man and the lower animals — Miscellaneous points of 
correspondence — Development— Rudimentary structures, muscles, 
sense-organs, hair, bones, reproductive organs, &c. — The bearing of 
these three great classes of facts on the origin of man. 

He who wishes to decide whether man is the modified descend- 
ant of some pre-existing form, would probably first enquire 
whether man varies, however slightly, in bodily structure and in 
mental faculties; and if so, whether the variations are trans- 
mitted to his offspring in accordance with the laws which prevail 
with the lower animals./ Again, are the variations the result, as 
far as our ignorance 'permits us to judge, of the same general 
causes, and are they governed by the same general laws, as in the 
case of other organisms; for instance, by correlation, the inherited 
effects of use and disuse, &c.? /Is man subject to similar mal- 
conformations, the result of arrested development, of reduplica- 
tion of parts, &;c., and does he display in any of his anomalies 
reversion to some former and ancient type of structure ? It might 
also naturally be enquired whether man, like so many other ani- 
mals, has given rise to varieties and sub-races, differing but 
slightly from each other, or to races differing so much that they 
must be classed as doubtful species? How are such races dis- 
tributed over the world; and how, when crossed, do they react 
on each other in the first and succeeding generations? And so 
with many other points. ' 

The enquirer would next come to the important point whether 
man tends to increase at so rapid a rate, as to lead to occasional 
2 



6 THE DESCENT OF MAN. 

severe struggles for existence; and consequently to beneficial vari- 
ations, whether in body or mind, being preserved, and injurious 
ones eliminated. Do the races or species of men, whichever term 
may be applied, encroach on and replace one another, so that 
some finally become extinct? Yv^e shall see that all these ques- 
tions, as indeed is obvious in respect to most of them, must be an- 
swered in the afiirmative, in the same manner as with the lower 
animals. But the several considerations just referred to may 
be conveniently deferred for a time: and we will first see how 
far the bodily structure of man shows traces, more or less plain, 
of his descent from some lower form. In succeeding chapters the 
mental powers of man, in comparison with those of the lower 
animals, will be considered. 

The Bodily Structure of Man.—U is notorious that man is con- 
structed on the same general type or model as other mammals. 
All the bones in his skeleton can be compared with correspond- 
ing bones in a monkey, bat, or seal. So it is with his muscles, 
nerves, blood-vessels and internal viscera. The brain, the most 
important of all the organs, follows the same law, as shown by 
Huxley and other anatomists. Bischoff,^ who is a hostile witness, 
admits that every chief fissure and fold in the brain of man has 
its analogy in that of the orang; but he adds that at no period of 
development do their brains perfectly agree; nor could perfect 
agreement be expected, for otherwise their mental powers would 
have been the same. Vulpian^ remarks: "Les differences reelles 
"qui existent entre I'encephale de I'homme et celui des singes 
"superieurs, sont bien minimes. II ne faut pas se faire d'illusions 
"a cet egard. L'homme est bien plus pres des singes anthropomor- 
"phes par les caracteres anatomiques de son cerveau que ceux-ci 
"ne le sont nonseulement des autres mammiferes, mais meme de 
"certains quadrumanes, des guenons et des macaques." But it 
would be superfluous here to give further details on the corre- 
spondence between man and the higher mammals in the structure 
of the brain and all other parts of the body. 

It may, however, be wortlji while to specify a few points, not 
directly or obviously connected with structure, by which this 
correspondence or relationship is well shown. 

Man is liable to receive from the lower animals, and to com- 
municate to them, certain diseases, as hydrophobia, variola, the 

1 'Grosshirnwindungen des Ivlenschen,' 1868, s. 96. The conclusions of 
this author, as well as those of Gratiolet and Aeby, concerning the 
brain, will be discussed by Prof. Huxley in the Appendix alluded to in 
the Preface to this edition. 

2 'Lee. sur la Phys.' 1866, p. 890, as quoted by M. Dally, 'L'Ordre des 
Prinaates ©t le Transformisme,' 1868, p. 29. 



HOMOLOGICAL STRUCTURES. 7 

glanders, syphilis, cholera, herpes, &c.;^ and this fact proves the 
close similarity* of their tissues and blood, both in minute struc- 
ture and composition, far more plainly than does their comparison 
under the best microscope, or by the aid of the best chemical 
analysis. Monkeys are liable to many of the same non-contagious 
diseases as we are; thus Rengger,^ who carefully observed for a 
long time the Cebus Azarae in its native land, found it liable to 
catarrh, with the usual symptoms, and which, when often recur- 
rent, led to consumption. These monkeys suffered also from 
apoplexy, inflammation of the bowels, and cataract in the eye. 
The younger ones when shedding their milk-teeth often died from 
fever. Medicines produced the same effect on them as on us. Many 
kinds of monkeys have a strong taste for tea, coffee, and spirit- 
uous liquors: they will also, as I have myself seen, smoke to- 
bacco with pleasure.^ Brehm asserts that the natives of north- 
eastern Africa catch the wild baboons by exposing vessels with 
strong beer, by which they are made drunk. He has seen some 
of these animals, which he kept in confinement, in this state; and 
he gives a laughable account of their behavior and strange 
grimaces. On the following morning they were very cross and 
dismal; they held their aching heads with both hands, and wore 
a most pitiable expression: when beer or wine was offered them, 
they turned away with disgust, but relished the juice of lemons.^ 
An American monkey, an Ateles, after getting drunk on brandy, 
would never touch it again, and thus was wiser than many men. 
These trifling facts prove how similar the nerves of taste must 
be in monkeys and man, and how similarly their whole nervous 
system is affected. 
Man is infested with internal parasites, sometimes causing fatal 

3 Dr. W. Lauder Lindsay has treated this subject at some length in 
the 'Journal of Mental Science,' July, 1871; and in the 'Edinburgh 
Veterinary Review,' July, 1858. 

* A Reviewer has criticized ('British Quarterly Review,' Oct. 1st, 1871, 
p. 472) what I have here said with much severity and contempt; but 
as I do not use the term identity, I cannot see that I am greatly in 
error. There appears to me a strong analogy between the same 
infection or contagion producing the same result or one closely similar, 
in two distinct animals, and the testing of two distinct fluids by the 
same chemical reagent. 

5 'Naturgeschichte der Saugethiere von Paraguay,' 1830, s. 50. 

^ The same tastes are common to some animals much lower in the 
scale. Mr. A. Nicols informs me that he kept in Queensland, in Aus- 
tralia, three individuals of the Phaseolarctus cinereus; and that, with- 
out having been taught in any way, they acquired a strong taste for 
rum, and for smoking tobacco. 

7 Brehm, 'Thierleben,' B. i. 1864, s. 75, 86. On the Ateles, s. 105. For 
other analogous statements, see s. 25, 107. 



S THE DESCENT OF MAN. 

effects; and is plagued by external parasites, all of which belong 
to the same genera or families as those infesting other mam- 
mals, and in the case of scabies to the same species.^ Man is 
subject, like other mammals, birds, and even insects," to that mys- 
terious law, which causes certain normal processes, such as ges- 
tation, as well as the maturation and duration of various diseases, 
to follow lunar periods. His wounds are repaired by the same 
process of healing; and the stumps left after the amputation of 
his limbs, especially during an early embryonic period, occasion- 
ally possess some power of regeneration, as in the lowest ani- 
mals.^° 

The whole process of that most important function, the repro- 
duction of the species, is strikingly the same in all mammals, 
from the first act of courtship by the male," to the birth and 
nurturing of the young. Monkeys are born in almost as helpless 
a condition as our own infants; and in certain genera the young 
differ fully as much in appearance from the adults, as do our 
children from their full-grown parents.^ It has been urged by 
some writers, as an important distinction, that with man the 
young arrive at maturity at a much later age than with any other 
animal: but if we look to the races of mankind which inhabit 
tropical countries the difference is not great, for the orang is 
believed not to be adult till the age of from ten to fifteen years." 
Man differs from woman in size, bodily strength, hairiness, &c., 

8 Dr. W. Lauder Lindsay, 'Edinburgh Vet. Review,' July 1858, p. 13. 

8 With respect to insects see Dr. Laycock, "On a General Law of 
Vital Periodicity," 'British Association,' 1842. Dr. MaccuUoch, 'Silli- 
man's North American Journal of Science,' vol. xvli. p. 305, has seen a 
dog suffering- from tertian ague. Hereafter I shall return to this sub- 
ject. 

10 1 have given the evidence on this head in my 'Variation of Animals 
and Plants under Domestication,' vol. ii. p. 15, and more could be added. 

11 "Mares e diversis generibus Quadrumanorum sine dubio dignoscunt 
"feminas humanas a maribus. Primum, credo, odoratu, postea as- 
"pectu. Mr. Youatt, qui diu in Hortis Zoologicis (Bestiariis) medicus 
"animalium erat, vir in rebus observandis oautus et sagax, hoc mihi 
"certissime probavit, et curatores ejusdem loci et alii e ministris 
"confirmaverunt. Sir Andrew Smith et Brehm notabant iden in Cyno- 
"cephalo. Illustrissimus Cuvier etiam narrat multa de hac re, qua ut 
"opinor, nihil turpius potest indicari inter omnia hominibus et Quad- 
"rumanis communia. Narrat enim Cynocephalum quendam in furorem 
"incidere aspectu feminarum aliquarum, sed nequaquam accendi tanto 
"furore ab omnibus. Semper eligebat juniores, et dignoscebat in 
"turba, et advocabat voce gestuque." 

12 This remark is made with respect to Cynocephalus and the an- 
thropomorphous apes by Geoffroy Saint-Hilaire and F. Cuvier, 'Hist. 
Nat. des Mammiferes,' tom. i. 1824. , 

13 Huxley, 'Man's Place in Nature,' 1863, p. 34. 



HOMOLOGICAL STRUCTURES. S 

as well as in mind, in the same manner as do the two sexes of 
many mammals. So that the correspondence in general structure, 
in the minute structure of the tissues, in chemical composition 
and in constitution, between man and the higher animals, es- 
pecially the anthropomorphous apes, is extremely close. 

Emhryonic Development. — Man is developed from an ovule, 
about the 125th of an inch in diameter, which differs in no respect 
from the ovules of other animals. The embryo itself at a very 
early period can hardly be distinguished from that of other mem- 
bers of the vertebrate kingdom. At this period the arteries run 
in arch-like branches, as if to carry the blood to branchiae which 
are not present in the higher vertebrata, though the slits on the 
sides of the neck still remain (f, g, fig. 1), marking their former 
position. At a somewhat later period, when the extremities are de- 
veloped, "the feet of lizards and mammals," as the illustrious Von 
Baer remarks, "the wings and feet of birds, no less than the hands 
"and feet of man, all arise from the same fundamental form." It 
is, says Prof. Huxley,^* "quite in the later stages of development 
"that the young human being presents marked differences from 
"the young ape, while the latter departs as much from the dog in 
"its developments, as the man does. Startling as this last asser- 
"tion may appear to be, it is demonstrably true." 

As some of my readers may never have seen a drawing of an 
embryo, I have given one of man and another of a dog, at about 
the same early stage of development, carefully copied from two 
works of undoubted accuracy.^" 

After the foregoing statements made by such high authorities, 
it would be superfluous on my part to give a number of borrowed 
details, showing that the embryo of man closely resembles that 
of other mammals. It may, however, be added, that the human 
embryo likewise resembles certain low forms when adult in vari- 
ous points of structure. For instance, the heart at first exists as a 
simple pulsating vessel; the excreta are voided through a cloacal 
passage; and the os coccyx projects like a true tail, "extending 

1* 'Man's Place in Nature,' 1863, p. 67. 

15 The human embryo (upper flg-.) is from Ecker, 'Icones Phys.,' 1851- 
1859, tab. XXX. fig. 2. This embryo was ten lines in length, so that the 
drawing is much magnified. The embryo of the dog is from Bischoff, 
'Entwicklungsgeschichte des Hunde-Eies,' 1845, tab. xi. fig. 42 b. This 
drawing is five times magnified, the embryo being twenty-five days old. 
The internal viscera have been omitted, and the uterine appendages 
in both drawings removed. I was directed to these figures by Prof. 
Huxley, from whose work, 'Man's Place in Nature,' the idea of giving 
them was taken. Hackel has also given analogous drawings in his 
'Schopfungsgesohichte.* 



JO 



THE DESCENT OP MAN. 




Fig. !• Upper figure human embryo, from Ecker. Lower figure that 
of a dog, from Bischoff. 

a„ Fore-brain, cerebral hemispheres, &c. 

b. Mid-brain, corpora quadrigemina. 

c. Hind-brain, cerebellum, medulla oblongata. 

d. Eye. 

e. Ear. 

f. First visceral arch. 

g. Second visceral arch. 

H. "Vertebral columns and muscles process of development, 
i. Anterior extremity. 
K. Posterior extremity. 
L. Tail or os coccyx. 



RUDIMENTS. 11 

"considerably beyond the rudimentary legs."" In the embryos of 
all air-breathing vertebrates, certain glands, called the corpora 
Wolffiana, correspond with, and act like the kidneys of mature 
fishes." Even at a later embryonic period, some striking resem- 
blances between man and the lower animals m.ay be observed. 
Bischoff says that the convolutions of the brain in a human foetus 
at the end of the seventh month reach about the same stage of 
development as in a baboon when adult." The great toe, as 
Prof. Owen remarks,^'' "which forms the fulcrum when standing 
"or walking, is perhaps the most characteristic peculiarity in the 
"human structure;" but in an embryo, about an inch in length, 
Prof. Wyman-^ found "that the great toe was shorter than the 
"others; and, instead of being parallel to them, projected at an 
"angle from the side of the foot, thus corresponding with the 
"permanent condition of this part in the quadrumana." I will 
conclude with a quotation from Huxley,-^ who after asking, does 
man originate in a different way from a dog, bird, frog or fish? 
says, "the reply is not doubtful for a moment; without question, 
"the mode of origin, and the early stages of the development of 
"man, are identical with those of the animals immediately below 
"him in the scale: without a doubt in these respects, he is far 
"nearer to apes than the apes are to the dog." 

Rudiments.— This subject, though not intrinsically more im- 
portant than the two last, will for several reasons be treated here 
more fully.™ Not one of the higher animals can be named which 
does not bear some part in a rudimentary condition; and man 
forms no exception to the rule. Rudimentary organs must be dis- 
tinguished from those that are nascent; though in some cases the 
distinction is not easy. The former are either absolutely useless, 
such as the mammse of male quadrupeds, or the incisor teeth of 
ruminants which never cut through the gums; or they are of such 
slight service to their present possessors, that we can hardly sup- 
pose that they were developed under the conditions which now ex- 

i« Prof. Wyman in 'Proc. of American Acad, of Sciences,' vol. iv. 
1860, p. 17. 

1'^ Owen, 'Anatomy of Vertebrates,' vol, i. p. 533. 

18 'Die Grosshirnwindungen des Menschen,' 1868, s. 95. 

18 'Anatomy of Vertebrates,' vol. ii. p. 553. 

20 'Proc. Soc. Nat. Hist.' Boston, 1863, vol. ix. p. 185. 

'^ 'Man's Place in Nature,' p. 65. 

22 1 had written a rough copy of this chapter before reading a valu*.' 
able paper, "Caratteri rudimentali in ordine all' origine del uomo'* 
('Annuario della Soc, d, Nat.,' Modena, 1867, p. 81), by G. Canestrini, 
to which paper I am considerably indebted. Hackel has given ad- 
mirable discussions on this whole subject, under the title of Dysteleo- 
logy, in his 'Generelle Morphologie' and 'Schopfungsgeschichte.' 



12 THE DESCENT OF MAN. 

ist. Organs in this latter state are not strictly rudimentary, but 
they are tending in this direction. Nascent organs, on the other 
hand, though not fully developed, are of high service to their pos- 
sessors, and are capable of further development. Rudimentary 
organs are eminently variable; and this is partly intelligible, as 
they are useless, or nearly useless, and consequently are no longer 
subjected to natural selection. They often become wholly sup- 
pressed. When this occurs, they are nevertheless liable to oc- 
casional reappearance through reversion — a circumstance well 
worthy of attention. 

The chief agents in causing organs to become rudimentary 
seem to have been disuse at that period of life when the organ is 
chiefly used (and this is generally during maturity), and also 
inheritance at a corresponding period of life. The term "disuse" 
does not relate merely to the lessened action of muscles, but in- 
cludes a diminished flow of blood to a part or organ, from being 
subjected to fewer alternations of pressure, or from becoming in 
any way less habitually active. Rudiments, however, may occur 
in one sex of those parts which are normally present in the 
other sex; and such rudiments, as we shall hereafter see, have 
often originated in a way distinct from those here referred to. In 
some cases, organs have been reduced by means of natural selec- 
tion, from having become injurious to the species under changed 
habits of life. The process of reduction is probably often aided 
through the two principles of compensation and economy of 
growth; but the later stages of reduction, after disuse has done 
all that can fairly be attributed to it, and when the saving to be 
effected by the economy of growth would be very small,^^ are diffi- 
cult to understand. The final and complete suppression of a part, 
already useless and much reduced in size, in which case neither 
compensation nor economy can come into play, is perhaps intelli- 
gible by the aid of the hypothesis of pangenesis. But as the 
whole subject of rudimentary organs has been discussed and 
illustrated in my former works,^* I need here say no more on this 
head. 

Rudiments of various muscles have been observed in many 
parts of the human body;=^ and not a few muscles, which are regu- 

23 Some g-ood criticisms on this subject have been g-iven by Messrs* 
Murie and Mivart, in 'Transact. Zoolog. Soc' 1869, vol. vii. p. 92. 

2* 'Variation of Animals and Plants under Domestication,' vol. ii. 
pp. 317 and 397. See also 'Orig-in of Species,' 5th edit. p. 535. 

25 For instance M. Richard ('Annales des Sciences Nat.' 3rd series, 
Zoolog. 1852, torn, xviii. p. 13) describes and figures rudiments of what 
he calls the "muscle pedieux de la main," which he says is sometimes 
"infinlment petit." Another muscle called "le tibial posterieur," is 
generally quite absent in the hand, but appears from time to time 
in a more or less rudimentary condition. 



RUDIMENTS. 13 

larly present in some of the lower animals can occasionally be 
detected in man in a greatly reduced condition. Every one must 
have noticed the power which many animals, especially horses, 
possess of moving or twitching their skin; and this is effected by 
the panniculus carnosus. Remnants of this muscle in an efficient 
state are found in various parts of our bodies; for instance, the 
muscle on the forehead, by which the eyebrows are raised. The 
platysma myoides, which is well developed on the neck, belongs 
to this system. Prof. Turner, of Edinburgh, has occasionally de- 
tected, as he informs me, muscular fasciculi in five different situ- 
ations, namely in the axillae, near the scapulae, &c., all of which 
must be referred to the system of the panniculus. He has also 
shown^^ that the musculous sternalis or sternalis brutorum, which 
is not an extension of the rectus abdominalis, but is closely allied 
to the panniculus, occurred in the proportion of about three per 
cent, in upwards of 600 bodies: he adds, that this muscle affords 
"an excellent illustration of the statement that occasional and 
"rudimentary structures are especially liable to variation in ar- 
"rangement." 

Some few persons have the power of contracting the super- 
ficial muscles on their scalps; and these muscles are in a variable 
and partially rudimentary condition. M. A. de Candolle has com- 
municated to me a curious instance of the long-continued per- 
sistence or inheritance of this power, as well as of its unusual de- 
velopment. He knows a family, in which one member, the pres- 
ent head of the family, could, when a youth, pitch several heavy 
books from his head by the movement of the scalp alone; and he 
won wagers by performing this feat. His father, uncle, grand- 
father, and his three children possess the same power to the 
same unusual degree. This family became divided eight genera- 
tions ago into two branches; so that the head of the above-men- 
tioned branch is cousin in the seventh degree to the head of 
the other branch. This distant cousin resides in another part 
of France; and on being asked whether he possessed the same 
faculty, immediately exhibited his power. This case offers a good 
illustration how persistent may be the transmission of an abso- 
lutely useless faculty, probably derived from our remote semi- 
human progenitors; since many monkeys have, and frequently 
use the power, or largely moving their scalps up and down.^^ 

The extrinsic muscles which serve to move the external ear, 
and the intrinsic muscles which move the different parts, are in a 
rudimentary condition in man, and they all belong to the system 
of the panniculus; they are also variable in development, or at 



2« Prof. W. Turner, 'Proc. Royal Soc. Edinburg-h,' 1866-67, p. 65. 
^See my 'Expression of the Emotions in Man and Animals,' 1872, 
p. 144. 



14 THE DESCENT OF MAN. 

least in function. I have seen one man who could draw the whole 
ear forwards; other men can draw it upwards; an- 
other who could draw it backwards;-** and from what 
one of these persons told me, it is probable that most of us, by 
often touching our ears, and thus directing our attention towards 
them, could recover some power of movement by repeated trials. 
The power of erecting and directing the shell of the ears to the 
various points of the compass, is no doubt of the highest service 
to many animals, as they thus perceive the direction of danger; 
but I have never heard, on sufficient evidence, of a man who pos- 
sessed this power, the one which might be of use to him. The 
whole external shell may be considered a rudiment, together with 
the various folds and prominences (helix and anti-helix, tragus 
and anti-tragus, &c.) which in the lower animals strengthen 
and support the ear when erect, without adding much to its 
weight. Some authors, however, suppose that the cartilage of the 
shell serves to transmit vibrations to the acoustic nerve; but Mr. 
Toynbee,-'' after collecting all the known evidence on this head, 
concludes that the external shell is of no distinct use. The ears 
of the chimpanzee and orang are curiously like those of man, 
and the proper muscles are likewise but very slightly developed.^" 
I am also assured by the keepers in the Zoological Gardens that 
these animals never move or erect their ears; so that they are 
in an equally rudimentary condition with those of man, as far as 
function is concerned. Why these animals, as well as the pro- 
genitors of man, should have lost the power of erecting their 
ears, we cannot say. It may be, though I am not satisfied with 
this view, that owing to their arboreal habits and great strength 
they were but little exposed to danger, and so during a lengthened 
period moved their ears but little, and thus gradually lost the 
power of moving them. This would be a parallel case with that 
of those large and heavy birds, which, from inhabiting oceanic 
islands, have not been exposed to the attacks of beasts of prey, 
and have consequently lost the power of using their wings for 
flight. The inability to move the ears in man and several apes 
is, however, partly compensated by the freedom with which they 
can move the head in a horizontal plane, so as to catch sounds 
from all directions. It has been asserted that the ear of man alone 



28 Canestrini quotes Hyrtl. ('Annuarie della Soc. dei Naturalist!,' Mo- 
dena, 1867, p. 97) to the same effect. 

29 'The Diseases of the Ear,' by J. Toynbee, F. R. S., 1860, p. 12. A 
disting-uished physiologist, Prof. Preyer, informs me that he had lately 
been experimenting' on the function of the shell of the ear, and has 
come to nearly the same conclusion as that given here. 

30 Prof. A. Macalister, 'Annals and Mag-, of Nat. History,' vol. vii. 
1871, p. 342. 



RUDIMENTS. 



15 



possesses a lobule; but "a rudiment of it is found in the gorilla;"^ 
and, as I hear from Prof. Preyer, it is not rarely absent in the 

negro. 

The celebrated sculptor, Mr. Woolner, informs me of one little 
peculiarity in the external ear, which he has often observed both 
in men and women, and of which he perceived the full signifi- 
cance. His attention was first called to the subject whilst at 
work on his figure of Puck, to which he had given pointed ears. 
He was thus led to examine the ears of various monkeys, and sub- 
sequently more carefully those of man. The peculiarity consists 
in a little blunt point, projecting from the inwardly folded margin, 
or helix. When present, it is developed at birth, and, according 
to Prof. Ludwig Meyer, more frequently in man than in v/oman. 
Mr. Woolner made an exact model of one such case, and sent me 
the accompanying drawing. (Fig. 2.) 
These points not only project inwards 
towards the center of the ear, but often 
a little outwards from its plane, so as 
to be visible when the head is viewed 
from directly in front or behind. They 
are variable in size, and somewhat in 
position, standing either a little higher 
or lower; and they sometimes occur 
on one ear and not on the other. They 
are not confined to mankind, for I ob- 
served a case in one of the spider- 
monkeys (Ateles beelzebuth) in our 

Zoological Gardens; and Dr. E. Ray -c.- o ^ -p 

Lankester informs me of another case modelled and'dr awn by 
in a chimpanzee in the gardens at Mr. Woolner. 
Hamburg. The helix obviously con- a. The projecting point, 
sists of the extreme margin of the ear folded inwards; and this 
folding appears to be in some manner connected with the whole 
external ear being permanently pressed backwards. In many 
monkeys, which do not stand high in the order, as baboons and 
some species of macacus,^^ the upper portion of the ear is slightly 
pointed, and the margin is not at all folded inwards; but if the 
margin were to be thus folded, a slight point would necessarily 
project inwards towards the center, and probably a little out- 
wards from the plane of the ear; and this I believe to be their 
origin in many cases. On the other hand. Prof. L. Meyer, in an 
able paper recently published,^^ maintains that the whole case is 




31 Mr. St. George Mivart, 'Elementary Anatomy,' 1873, p. 396. 

32 See also some remarks, and the drawings of the ears of the Lemu- 
roidea, in Messrs. Murie and Mivart's excellent paper in 'Transact. 
Zoolog. Soc' vol. vii. 1869, pp. 6 and 90. 

33 Ueber das Darwin'sche Spitzohr, Archiv fur Path. Anat. und Phys. 
1871, p. 485. 



16 THE DESCENT OP MAN. 

one of mere variability; and that the projections are not real 
ones, but are due to the internal cartilage on each side of the 
points not having been fully developed. I am quite ready to 
admit that this is the correct explanation in many instances, as 
in those figured by Prof. Meyer, in which there are several minute 
points, or the whole margin is sinuous. I have myself seen, 
through the kindness of Dr. L. Down, the ear of a microcephalous 
idiot, on which there is a projection on the outside of the helix, 
and not on the inward folded edge, so that this point can have 
no relation to a former apex of the ear. Nevertheless in some 
cases, my original view, that the points are vestiges of the tips 
of formerly erect and pointed ears, still seems to me probable. I 
think so from the frequency of their occurrence, and from the gen- 
eral correspondence in position with that of the tip of a pointed 
ear. In one case, of which a photograph has been sent me, the 
projection is so large, that supposing, in accordance with Prof. 
Meyer's view, the ear to be made perfect by the equal development 
of the cartilage throughout the whole extent of the margin, it 
would have covered fully one-third of the whole ear. Two cases 
have been communicated to me, one in North America, and the 
other in England, in which the upper margin is not at all folded 
inwards, but is pointed, so that it closely resembles the pointed 
ear of an ordinary quadruped in outline. In one of these cases, 
which was that of a young child, the father compared the ear with 
the drawing which I have given^* of the ear of a monkey, the 
Cynopithecus niger, and says that their outlines are closely sim- 
ilar. If, in these two cases, the margin had been folded inwards 
in the normal manner, an inward projection must have been 
formed. I may add that in two other cases the outline still re- 
mains somewhat pointed, although the margin of the upper part 
of the ear is normally folded inwards — in one of them, however, 
very narrowly. The follow^ing woodcut (No. 3) is an accurate 
copy of a photograph of the foetus of an orang (kindly sent me 
by Dr. Nitsche), in which it may be seen how different the pointed 
outline of the ear is at this period from its adult condition, when 
it bears a close general resemblance to that of man. It is evident 
that the folding over of the tip of such an ear, unless it changed 
greatly during its further development, would give rise to a point 
projecting inwards. On the whole, it still seems to me probable 
that the points in question are in some cases, both in man and 
apes, vestiges of a former condition. 

The nictitating membrane, or third eyelid, with its accessory 
muscles and other structures, is especially well developed in 
birds, and is of much functional importance to them as it can 
be rapidly drawn across the whole eye-ball. It is found in some 

8* 'The Expression of the Emotions,' p. 136. 



HtJDIMENTS. 17 

reptiles and amphibians, and in certain fishes, as in sharks. It 
is fairly well developed in the two lower divisions of the mam- 
malian series, namely, in the monotremata and marsupials, and 
in some few of the higher mammals, as in the walrus. But in 




Fig. 3. Foetus of an Orang. Exact copy of a photograph, showing 
the form of the ear at this early age. 

man, the quadrumana, and most other mammals, it exists, as is 
admitted by all anatomists, as a mere rudiment, called the 
semilunar fold.^^ 

The sense of smell is of the highest importance to the greater 
number of mammals — to some, as the ruminants, in warning 
them of danger; to others, as the carnivora, in finding their prey; 
to others, again, as the wild boar, for both purposes combined. 
But the sense of smell is of extremely slight service, if any, even 
to the dark colored races of men, in whom it is much more highly 
developed than in the white and civilized races.^^ Nevertheless it 

85 Muller's 'Elements of Physiology,' Eng. translat., 1842, vol, ii. p. 
1117. Owen, 'Anatomy of Vertebrates,' vol. iii. p. 260; ibid on the Wal- 
rus, 'Proc. Zoolog. Soc' November 8th, 1854. See also R. Knox, 'Great 
Artists and Anatomists,' p. 106. This rudiment apparently is somewhat 
larger in Negroes and Australians than in Europeans, see Carl Vogt, 
'Lectures on Man,' Eng. trajislat. p. 129. 

3« The account given by Humboldt of the power of smell possessed by 
the natives of South America is well known, and has been confirmed 
by others. M. Houzeau ('Etudes sur les Facultes Mentales,' &c., torn. 
i. 1872, p. 91) asserts that he repeatedly made experiments, and proved 
that Negroes and Indians could recognize persons in the dark by their 
odor. Dr. W. Ogle has made some curious observations on the con- 
nection between the power of smell and the coloring matter of the mu- 



18 THE DESCENT OF MAN. 

does not warn them of danger, nor guide them to their food; nor 
does it prevent the Esquimaux from sleeping in the most fetid at- 
mosphere, nor many savages from eating half-putrid meat. In 
Europeans the power differs greatly in different individuals, as I 
am assured by an eminent naturalist who possesses this sense 
highly developed, and who has attended to the subject. Those 
who believe in the principle of gradual evolution, will not readily 
admit that the sense of smell in its present state was originally 
acquired by man, as he now exists. He inherits the power in an 
enfeebled and so far rudimentary condition, from some early pro- 
genitor, to whom it was highly serviceable, and by whom it was 
continually used. In those animals which have this sense highly 
developed, such as dogs and horses, the recollection of persons 
and of places is strongly associated with their odor; and we can 
thus perhaps understand how it is, as Dr. Maudsley has truly re- 
marked," that the sense of smell in man "is singularly effective 
"in recalling vividly the ideas and images of forgotten scenes and 
"places." 

Man differs conspicuously from all tihe other Primates in being 
almost naked. But a few short straggling hairs are found over 
the greater part of the body in the man, and fine down on that of 
the woman. The different races differ much in hairiness; and in 
the individuals of the same race the hairs are highly variable, 
not only in abundance, but likewise in position: thus in some 
Europeans the shoulders are quite naked, whilst in others they 
bear thick tufts of hair.^« There can be little doubt that the hairs 
thus scattered over the body are the rudiments of the uniform 
hairy coat of the lower animals. This view is rendered all the 
more probable, as it is known that fine, short, and pale-colored 
hairs on the limbs and other parts of the body, occasionally be- 
come developed into "thickset, long, and rather coarse dark 
"hairs," when abnormally nourished near old-standing infiamed 
surfaces.^® / 

I am informed by Sir James Paget that often several members 
of a family have a few hairs in their eyebrows much longer than 
the others; so that even this slight peculiarity seems to be in- 
herited. These hairs, too, seem to have their representatives; for 
in the chimpanzee, and in certain species of Macacus, there are 



cous membrane of the olfactory region, as well as of the skin of the 
body. I have, therefore, spoken in the text of the dark-colored races 
having- a finer sense of smell than the white races. See his paper 'Med- 
ico-Chirurgical Transactions,' London, vol. liii., 1870, p. 276. 
87 'The Physiology and Pathology of Mind,' 2nd edit. 1868, p. 134. 

38 Eschricht, Ueber die Richtung der Haare am menschlichen Korper, 
'Muller's Archiv fur Anat. und Phys.' 1837, s. 47. I shall often have 
to refer to this very curious paper. 

39 Paget, 'Lectures on Surgical Pathology,' 1853, vol. i. p. 71. 



RUDIMENTS. 19 

scattered hairs of considerable length rising from the naked skin 
above the eyes, and corresponding to our eyebrows; similar long 
hairs project from the hairy covering of the superciliary ridges in 
some baboons. 

The fine wool-like hair, or so-called lanugo, with which the 
human foetus during the sixth month is thickly covered, offers a 
more curious case. It is first developed, during the fifth month, 
on the eyebrows and face, and especially round the mouth, where 
it is much longer than that on the head. A mustache of this 
kind was observed by Eschricht^" on a female foetus; but this is 
not so surprising a circumstance as it may first appear, for the 
two sexes generally resemble each other in all external characters 
during an early period of growth. The direction and arrange- 
ment of the hairs on all parts of the foetal body are the same 
as in the adult, but are subject to much variability. The whole 
surface, including even the forehead and ears, is thus thickly 
clothed; but it is a significant fact that the palms of the hands 
and the soles of the feet are quite naked, like the inferior surfaces 
of all four extremities in most of the lower animals. As this 
can hardly be an accidental coincidence, the woolly covering of 
the foetus probably represents the first permanent coat of hair 
in those mammals which are born hairy. Three or four cases have 
been recorded of persons born with their whole bodies and faces 
thickly covered with fine long hairs; and this strange condition 
is strongly inherited, and is correlated with an abnormal condition 
of the teeth.*^ Prof. Alex. Brandt informs me that he has com- 
pared the hair from the face of a man thus characterized, aged 
thirty-five, with the lanugo of a foetus, and finds it quite similar 
in texture; therefore, as he remarks, the case may be attributed 
to an arrest of development in the hair, together with its con- 
tinued growth. Many delicate children, as I have been assured 
by a surgeon to a hospital for children, have their backs covered 
by rather long silky hairs; and such cases probably come under 
the same head. 

It appears as if the posterior molar or wisdom-teeth were tend- 
ing to become rudimentary in the more civilized races of man. 
These teeth are rather smaller than the other molars, as is like- 
wise the case with the corresponding teeth in the chimpanzee and 
orang; and they have only two separate fangs. They do not cut 
through the gums till about the seventeenth year, and I have been 
assured that they are much more liable to decay, and are earlier 
lost than the other teeth; but this is denied by some eminent 



*o Eschricht, ibid. s. 40, 47. 

*^ See my 'Variation of Animals and Plants under Domestication,' vol. 
ii. p. 327. Prof. Alex. Brandt has recently sent me an additional case 
of a father and son, born in Russia, with thes.e peiculiaritie&. I have 
received drawing-s of both from Paris. 



20 THE DESCENT OF MAN. 

dentists. They are also much more liable to vary, both in structure 
and in the period of their development, than the other teeth.^^ j^ 
the Melanian races, on the other hand, the wisdom-teeth are usual- 
ly furnished with three separate fangs, and are generally sound; 
they also differ from the other molars in size, less than in the Cau- 
casian race.*8 Prof. Schaaffhausen accounts for this difference be- 
tween the races by "the posterior dental portion of the jaw being 
"always shortened" in those that are civilized,** and this shorten- 
ing may, I presume, be attributed to civilized men habitually 
feeding on soft, cooked food, and thus using their jaws less. I am 
informed by Mr. Brace that it is becoming quite a common prac- 
tice in the United States to remove some of the molar teeth of 
children, as the jaw does not grow large enough for the perfect 
development of the normal number.*^ 

With respect to the alimentary canal, I have met with an ac- 
count of only a single rudiment, namely the vermiform appendage 
of the caecum. The caecum is a branch or diverticulum of the intes- 
tine, ending in a cul-de-sac, and is extremely long in many of the 
lower vegetable-feeding mammals. In the marsupial koala it is ac- 
tually more than thrice as long as the whole body.*'' It is some- 
times produced into a long gradually-tapering point, and is some- 
times constricted in parts. It appears as if, in consequence of 
changed diet or habits, the caecum had become much shortened in 
various animals, the vermiform appendage being left as a rudi- 
ment of the shortened part. That this appendage is a rudiment, we 
may infer from its small size, and from the evidence which Prof. 
Canestrini*^ has collected of its variability in man. It is occasion- 
ally quite absent, or again is largely developed. The passage is 
sometimes completely closed for half or two-thirds of its length, 
with the terminal part consisting of a flattened solid expansion. In 
the orang this appendage is long and convoluted: in man it arises 
from the end of the short caecum, and is commonly from four to 
five inches in length, being only about the third of an inch in 
diameter. Not only is it useless, but it is sometimes the cause of 
death, of which fact I have lately heard two instances: this is due 
to small hard bodies, such as seeds, entering the passage, and 
causing inflammation.*^ 

*2 Dr. Webb, 'Teeth in Man and the Anthropoid Apes,' as quoted by 
Dr. C. Carter Blake in 'Anthropological Review,' July, 1867, p. 299. 

^ Owen, 'Anatomy of Vertebrates,' vol. iii. pp. 320, 321 and 325. 

** 'On the Primitive Form of the Skull,' Eng-. translat. in 'Anthropo- 
logical Review,' Oct. 1868, p. 426. 

^ Prof. Mantegazza writes to me from Florence that he has lately 
been studying the last molar teeth in the different races of man, and 
has come to the same conclusion as that given in my text, viz., that 
in the higher or civilized races they are on the road towards atrophy 
or elimination. 

*« Owen, 'Anatomy of Vertebrates,' vol. iii. pp. 416, 434, 441. 

♦^ 'Annuario della Soc. d. Nat.' Modena, 1867, p. 94. 

*»M. C. Martins ("De I'Unite Organique," in 'Revue des Deux Mon- 



RUDIMEN-rS. 21 

In St5me of the lower Quadrumana, in the Lemuridas and Carni- 
vora, as well as in many marsupials, there is a passage near the 
loYv^er end of the humerus, called the supra-condyloid foramen, 
through which the great nerve of the fore limb and often the great 
artery pass. Now in the humerus of man, there is generally a trace 
of this passage, which i's sometimes fairly well developed, being 
formed by a depending hook-like process of bone, completed by a 
band of ligament. Dr. Struthers,^'' who has closely attended to the 
subject, has now shown that this peculiarity is sometimes inherit- 
ed, as it has occurred in a father, and in no less than four out of 
his seven children. When present, the great nerve invariably 
passes through it; and this clearly indicates that it is the homo- 
logue and rudiment of the «upra-condyloid foramen of the lower 
animals. Prof. Turner estimates, as he informs me, that it oc- 
curs in about one per cent, of recent skeletons. But if the occa- 
sional development of this structure in man is, as seems probable, 
due to reversion, it is a return to a very ancient state of things, be- 
cause in the higher Quadrumana it is absent. 

There is another foramen or perforation in the humerus, occa- 
sionally present in man, which may be called the inter-condyioid. 
This occurs, but not constantly, in various anthropoid and other 
apes,^" and likewise in many of the lower animals. It is remark- 
able that this perforation seems to have been present in man much 
more frequently during ancient times than recently. Mr. Busk^^ 
has collected the following evidence on this head: Prof. Broca "no- 
"ticed the perforation in four and a half per cent, of the arm-bones 
"collected in the 'Cimetiere du Sud,' at Paris; and in the Grotto of 
"Orrony, the contents of which are referred to the Bronze period, 
"as many as eight humeri out of thirty-two were perforated; but 
"this extraordinary proportion, he thinks, might be due to the cav- 
"ern having been a sort of 'family vault,' Again, M. Dupont found 
"thirty per cent, of perforated bones in the caves of the Valley of 
"the Lesse, belonging to the Reindeer period; whilst M. Leguay, in 

des,' June 15, 1862, p. 16), and Hackel ('Generelle Morphologie,' B. ii. s. 
278), have both remarked on the singular fact of this rudiment some- 
times causing- death. 

*9 With respect to inheritance, see Dr. Struthers in the 'Lancet,' Feb. 
15, 1873, and another important paper, ibid., Jan. 24, 1863, p. 83. Dr. 
Knox, as I am informed, was the first anatomist who drew attention 
to this peculiar structure in man; see his 'Great Artists and Anato- 
mists,' p. 63. See also an important memoir on this process by Dr. 
Gruber, in the 'Bulletin de I'Acad. Imp. de St. Petersbourg, torn, xii 
1867, p. 448. 

50 Mr. St. George Mivart, 'Transact. Phil. Soc' 1867, p. 310. 

51 "On the Caves of Gibraltar," 'Transact. Internat. Congress of Pre- 
hlst. Arch.' Third Session, 18G9, p. 159. Prof. Vv^yman has lately shown 
(Fourth Annual Report, Peabody Museum, 1871, p. 20), that this per- 
foration is present in thirty-one per cent, of some human remains 
from ancient mounds in the Western United States, and in Florida. 
It frequently occurs in the negro. 

3 



2^ THE DESCENT OP MAN. 

"a sort of dolmen at Argenteuil, observed twenty-five per cent, to 
"be perforated; and M. Pruner-Bey found twenty-six per cent, in 
"the same condition in bones from Vaureal. Nor should it be left 
"unnoticed that M. Pruner-Bey states that this condition is com- 
■'mon in Guanche skeletons." It is an interesting fact that ancient 
races, in this and several other cases, more frequently present 
structures which resemble those of the lower animals than do the 
modern. One chief cause seems to be that the ancient races stand 
somewhat nearer in the long line of descent to their remote ani- 
mal-like progenitors. 

In man, the os coccyx, together with certain other vertebrae here- 
after to be described, though functionless as a tail, plainly repre- 
sent this part in other vertebrate animals. At an early embryonic 
period it is free, and projects beyond the lower extremities; as may 
be seen in the drawing (Fig. 1.) of a human embryo. Even after 
birth it has been known, in certain rare and anomalous cases,^^ to 
form a small external rudiment of a tail. The os coccyx is short, 
usually including only four vertebrse, all anchylosed together: and 
these are in a rudimentary condition, for they consist, with the 
exception of the basal one, of the centrum alone.^^ They are fur- 
nished with some small muscles; one of which, as I am informed 
by Prof. Turner, has been expressly described by Theile as a ru- 
dimentary repetition of the extensor of the tail, a muscle which 
is so largely developed in many mammals. 

The spinal cord in man extends only as far downwards as the 
last dorsal or first lumbar vertebra; but a thread-like structure 
(the filum terminale) runs down the axis of the sacral part of the 
spinal canal, and even along the back of the coccygeal bones. The 
upper part of this filament, as Prof. Turner informs me, is un- 
doubtedly homologous with the spinal cord; but the lower part ap- 
parently consists merely of the pia mater, or vascular investing 
membrane. Even in this case the os coccyx may be said to possess 
a vestige of so important a structure as the spinal cord, though no 
longer enclosed within a bony canal. The following fact, for which 
I am also indebted to Prof. Turner, shows how closely the os coc- 
cyx corresponds with the true tail in the lower animals: Luschka 
has recently discovered at the extremity of the coccygeal bones a 
very peculiar convoluted body, which is continuous with the mid- 
dle sacral artery; and this discovery led Krause and Meyer to ex- 
amine the tail of a monkey (Macacus), and of a cat, in both of 

S2 Quatrefages has lately collected the evidence on this subject. 
'Revue des Cours Scientifiques,' 1867-1868, p. 625. In 1840 Fleischmann 
exhibited a human foetus bearing a free tail, which, as is not always 
the case, included vertebral bodies; and this tail was critically exam- 
ined by the many anatomists present at the meeting of naturalists at 
Erlang-en (see Marshall in Niederlandischen Archiv fur Zoologie, Pp* 
cember, 1871.) 

63 Owen, 'On the Nature of Limbs,' 1849, p. 114. 



RUDIMENTS. 23 

■whicli they found a similarly convoluted body, though not at the 
extremity. 

The reproductive system offers various rudimentary structures; 
but these differ in one important respect from the foregoing 
cases. Here we are not concerned with the vestige of a part which 
does not belong to the species in an efficient state, but with a 
part efficient in the one sex, and represented in the other by a 
mere rudiment. Nevertheless, the occurrence of such rudiments 
is as difficult to explain, on the belief of the separate creation of 
each species, as in the foregoing cases. Hereafter I shall have to 
recur to these rudiments, and shall show that their presence gen- 
erally depends merely on inheritance, that is, on parts acquired 
by one sex having been partially transmitted to the other. I will 
in this place only give some instances of such rudiments. It is 
well known that in the males of all mammals, including man, rudi- 
mentary mammae exist. These in several instances have become 
well developed, and have yielded a copious supply of milk. Their 
essential identity in the two sexes is likewise shown by their oc- 
casional sympathetic enlargement in both during an attack of the 
measles. The vesicula prostatica, which has been observed in 
many male mammals, is now universally acknowledged to be 
the homologue of the female uterus, together with the connected 
passage. It is impossible to read Leuckart's able description 
of this organ, and his reasoning, without admitting the justness 
of his conclusion. This is especially clear in. the case of those 
mammals in which the true female uterus bifurcates, for in the 
males of these the vesicula likewise bifurcates.^* Some other rudi- 
mentary structures belonging to the reproductive system might 
have been here adduced.^^ 

The bearing of the three great classes of facts now given is 
unmistakable. But it would be superfluous fully to recapitulate 
the line of argument given in detail in my 'Origin of Species.' 
The homological construction of the whole frame in the members 
of the same class is intelligible, if we admit their descent from 
a common progenitor, together with their subsequent adaptation 
to diversified conditions. On any other view, the similarity of 
pattern between the hand of a man or monkey, the foot of a 
horse, the flipper of a seal, the wing of a bat, &c., is utterly 
inexplicable.^® It is no scientific explanation to assert that they 



B4Leuckart, in Todd's 'Cyclop, of Anat.' 1849-52, vol. iv. p. 1415. In 
man this organ is only from three to six lines in length, but, like so 
many other rudimentary parts, it is variable in development as well as 
in other characters. 

^ See, on this subject, Owen, 'Anatomy of Vertebrates,' vol. iii. pp. 
675, 676, 706. 

^ Prof. Bianconi, in a recently published work, illustrated by ad- 
mirable engravings ('La Theorie Darwinienne et la creation dite inde- 
pendante,' . 1874), endeavors to show that homological structures, in 
the above and other cases, can be fully explained on mechanical prin» 



24 THE DESCENT OF MAN. 

have all been formed on the same ideal plan. With respect to 
development, we can clearly understand, on the principle of varia- 
tions supervening at a rather late embryonic period, and being 
inherited at a corresponding period, how it is that the embryos 
of wonderfully different forms should still retain, more or less 
perfectly, the structure of their common progenitor. No other 
explanation has ever been given of the marvelous fact that the 
embryos of a man, dog, seal, bat, reptile, &c., can at first hardly 
be distinguished from each other. In order to understand the 
existence of rudimentary organs, we have only to suppose that a 
former progenitor possessed the parts in question in a perfect 
state, and that under changed habits of life they became greatly 
reduced, either from simple disuse, or through the natural selec- 
tion of those individuals which were least encumbered with a 
superfluous part, aided by the other means previously indicated. 

Thus we can understand how it has come to pass that man and 
all other vertebrate animals have been constructed on the same 
general model, why they pass through the same early stages of 
development, and why they retain certain rudiments in common. 
Consequently we ought frankly to admit their community of 
descent; to take any other view, is to admit that our own struc- 
ture, and that of all the animals around us, is a mere snare laid 
to entrap our judgment. This conclusion is greatly strengthened, 
if we look to the members of the whole animal series, and con- 
sider the evidence derived from their affinities or classification, 
their geographical distribution and geological succession. It is 
only our natural prejudice, and that arrogance which made our 
forefathers declare that they were descended from demi-gods, 
which leads us to demur to this conclusion. But the time will be- 
fore long come, when it will be thought wonderful that naturalists, 
who were well acquainted with the comparative structure and de- 
velopment of man, and other mammals, should have believed that 
each was the work of a separate act of creation. 

ciples in accordance with their uses. No one has shown so well, how 
admirably such structures are adapted for their final purpose; and 
this adaptation can, as I believe, be explained through natural selection. 
In considering the wing of a bat, he brings forward (p. 218) what ap- 
pears to me (to use Auguste Comte's words) a mere metaphysical 
principle namely, the preservation "in its integrity of the mammalian 
"nature of the animal." In only a few cases does he discuss rudiments, 
and then only those parts which are partially rudimentary, such as the 
little hoofs of the pig and ox, which do not touch the ground; these 
he shows clearly to be of service to the animal. It is unfortunate that 
he did not consider such cases as the minute teeth, which never cut 
through the jaw in the ox, or the mammae of male quadrupeds, or the 
wings of certain beetles, existing under the soldered wing-covers, or 
the vestiges of the pistil and stamens in various flov/ers, and many 
other such cases. Although I greatly admire Prof. Bianconi's work, 
yet the belief now held by most naturalists seems to me left unshaken, 
that homological structures are inexplicable on the principle of mere 
adaptation. 



MANNER OF DEVELOPMENT. 2£ 



CHAPTER II. 

ON THE MANNER OF DEVELOPMENT OF MAN 
FROM SOME LOWER FORM. 

Variability of body and mind in man— Inheritance— Causes of varia- 
bility—Laws of variation the same in man as in the lower animals- 
Direct action of the conditions of life — Effects of the increased use 
and disuse of parts— Arrested development— Reversion— Correlated 
variation— Rate of increase — Checks to increase — Natural selection — 
Man the most dominant animal in the world — Importance of his cor- 
poreal structure — The causes which have led to his becoming- erect^ 
Consequent chang-es of structure — Decrease in size of the canine 
teeth— Increased size and altered shape of the skull — ^Nakedness — 
Absence of a tail— Defenseless condition of man. 

It is manifest that man is now subject to much variability. No 
two individuals of the same race are quite alike. We may compare 
millions of faces, and each will be distinct. There is an equally 
great amount of diversity in the proportions and dimensions of 
the various parts of the body; the length of the legs being one 
of the most variable points.^ Although in some quarters of the 
world an elongated skull, and in other quarters a short skull 
prevails, yet there is great diversity of shape even within the 
limits of the same race, as with the aborigines of America and 
South Australia — the latter a race "probably as pure and homo- 
"geneous in blood, customs, and language as any in existence" — 
and even with the inhabitants of so confined an area as the Sand- 
wich Islands.^ An eminent dentist assures me that there is nearly 
as much diversity in the teeth as in the features. The chief ar- 
teries so frequently run in abnormal courses, that it has been 
found useful for surgical purposes to calculate from 1040 corpses 

1 'Investigations in Military and Anthropolog. Statistics of American 
Soldiers,' by B. A. Gould, 1869, p. 256. 

2 With respect to the "Cranial forms of the American aborigines," 
see Dr. Aitken Meigs in 'Proc. Acad. Nat. Sci.' Philadelphia, May, 1868, 
On the Australians see Huxley, in Lyell's 'Antiquity of Man,' 1863, p. 
87. On the Sandwich Islanders, Prof. J. Wym^an, 'Observations on Cra- 
nia,' Boston, 1868, p. 18. 



26 THE DESCENT OF MAN. 

how often each course prevails.^ The muscles are eminently 
variable: thus those of the foot were found by Prof. Turner^ not 
to be strictly alike in any two out of fifty bodies; and in some 
the deviations were considerable. He adds, that the power of per- 
forming the appropriate movements must have been modified in 
accordance with the several deviations. Mr. J. Wood has recorded' 
the occurrence of 295 muscular variations in thirty-six subjects, 
and in another set of the same number no less than 558 variations, 
those occurring on both sides of the body being only reckoned as 
one. In the last set, not one body out of the thirty-six was 
"found totally wanting in departures from the standard descrip- 
"tions of the muscular system given in anatomical text books." 
A single body presented the extraordinary number of twenty-five 
distinct abnormalities. The same muscle sometimes varies in 
many ways: thus Prof. Macalister describes'' no less than twenty 
distinct variations in the palmaris accessorius. 

The famous old anatomist, Wolff,^ insists that the internal 
viscera are more variable than the external parts: Nulla parti- 
cula est quse non aliter et aliter in aliis se habeat hominibus. He 
has even written a treatise on the choice of typical examples of 
the viscera for representation. A discussion on the beau-ideal 
of the liver, lungs, kidneys, &c., as of the human face divine, 
sounds strange in our earsi 

The variability or diversity of the mental faculties in men of 
the same race, not to mention the greater differences between 
the men of distinct races, is so notorious that not a word need 
here be said. So it is with the lower animal's. All who have had 
charge of menageries admit this fact, and we see it plainly in our 
dogs and other domestic animals. Brehm especially insists that 
each individual monkey of those which he kept tame ip Africa 
had its own peculiar disposition and temper: he mentions one 
baboon remarkable for its high intelligence; and the keepers in 
the Zoological Gardens pointed out to me a monkey, belonging 
to the New World division, equally remarkable for intelligence. 
Rengger, also, insists on the diversity in the various mental char- 
acters of the monkeys of the same species which he kept in Para- 
guay; and this diversity, as he adds, is partly innate, and partly 
the result of the manner in which they have been treated or 
educated.^ 



8 'Anatomy of the Arteries,' by R. Quain. Preface, vol. i. 1844. 

* 'Transact. Royal Soc. Edinburgrh,' vol. xxlv. pp. 175, 189. 

" 'Proc. Royal Soc' 1867, p. 544; also 1868, pp. 483, 524. There is a pre- 
vious paper, 1866, p. 229. 

« 'Proc. R. Irish Academy,' vol. x. 1868, p. 141. 

' 'Act. Acad. St. Petersburg-,' 1778, part ii. p. 217. 

8 Brehm, 'Thierleben,' B. i. s. 58, 87. Reng-ger. 'Saugethiere von Para- 
guay,' s. 57, 



MANNER OF DEVELOPMENT. 27 

I have elsewhere^ so fully discussed the subject of Inheritance, 
that I need here add hardly anything. A greater number of facts 
have been collected with respect to the transmission of the most 
trifling, as well as of the most important characters in man, than 
in any of the lower animals; though the facts are copious enough 
with respect to the latter. So in regard to mental qualities, their 
transmission is manifest in our dogs, horses, and other domestic 
animals. Besides special tastes and habits, general intelligence, 
courage, bad and good temper, &c., are certainly transmitted. With 
man we see similar facts in almost every family; and we now 
know, through the admirable labors of Mr. Galton,^" that genius 
which implies a wonderfully complex combination of high facul- 
ties, tends to be inherited; and, on the other hand, it is too certain 
that insanity and deteriorated mental powers likewise run in 
families. 

With respect to the causes of variability, we are in all cases 
very ignorant; but we can see that in man as in the lower ani- 
mals, they stand in some relation to the conditions to which each 
species has been exposed, during several generations. Domes- 
ticated animals vary more than those in a state of nature; and 
this is apparently due to the diversified and changing nature of 
the conditions to which they have been subjected. In this respect 
the different races of man resemble domesticated animals, and so 
do the individuals of the same race, when inhabiting a very wide 
area, like that of America. We see the influence of diversified 
conditions in the more civilized nations; for the members belong- 
ing to different grades of rank, and following different occupa- 
tions, present a greater range of character than do the members 
of barbarous nations. But the uniformity of savages has often 
been exaggerated, and in some cases can hardly be said to exist." 
It is, nevertheless, an error to speak of man, even if we look only 
to the conditions to which he has been exposed, as "far more 
domesticated"^^ than any other animal. Some savage races, such 
as the Australians, are not exposed to more diversified conditions 
than are many species which have a wide range. In another and 
much more important respect, man differs widely from any 

» 'Variation of Animals and Plants under pomestication,' vol. ii. 
chap. xii. 

18 'Hereditary Genius: an Inquiry into its Laws and Consequences,' 
1869. 

^ Mr. Bates remarks ('The Naturalist on the Amazons,' 1863, vol. ii. 
p. 159), with respect to the Indians of the same South American tribe, 
"no two of them were at all similar in the shape of the head; one man 
had an oval visage with fine features, and another was quite Mongol- 
ian in breadth and prominence of cheek, spread of nostrils, and 
obliquity of eyes." 

*2 Blumenbach, 'Treatises on Anthropolog.' Eng. translat., 1865, p. 205, 



2g THE DESCENT OF MAN. 

Strictly domesticated animal; for his breeding has never long 
been controlled, either by methodical or unconscious selection. 
No race or body of men has been so completely subjugated by 
other men, as that certain individuals should be preserved, and 
thus unconsciously selected, from somehow excelling in utility 
to their masters. Nor have certain m.ale and female individuals 
been intentionally picked out and matched, except in the well- 
known case of the Prussian grenadiers; and in this case man 
obeyed, as might have been expected, the lav/ of methodical selec- 
tion; for it is asserted that many tall men were reared in the 
villages inhabited by the grenadiers and their tall wives. In 
Sparta, also, a form of selection was follov/ed, for it was enacted 
that all children should be examined shortly after birth; the well- 
formed and vigorous being preserved, the others left to perish.^^* 

If we consider all the races of man as forming a single species, 

I his range is enormous; but some separate races, as the Americans 
? and Polynesians, have very wide ranges. It is a well-known 
I law that widely-ranging species are much more variable than 
\ species with restricted ranges; and the variability of man may 
with more truth be compared v/ith that of widely-ranging species, 
than with that of domesticated animals. 

Not only does variability appear to be induced in man and 
the lower animals by the same general causes, but in both the 

13 Mitford's 'History of Greece,' vol. i. p. 282. It appears also from 
a passage in Xenophon's 'Memorabilia,' B. ii. 4 (to which my attention 
has been called by the Rev. J. N. Hcare), that it was a well recognized 
principle with the Greeks, that men ought to select their wives with a 
view to the health and vigor of their children. The Grecian poet, 
Theognis, who lived 550 B. C, clearly saw how important selection, if 
carefully applied, would be for the improvement of mankind. He saw, 
likewise, that wealth often checks the proper action of sexual selec- 
tion. He thus writes: 

"With kine and horses, Kurnus! we proceed 
By reasonable rules, and choose a breed 
For profit and increase, at any price; 
Of a sound stock, without defect or vice. 
But, in the daily matches that we make, 
The price is everything: for money's sake. 
Men marry: women are in marriage given; 
The churl or ruffian, that in wealth has thriven. 
May match his offspring with the proudest race: 
Thus everything is mix'd, noble and base! 
If then in outward manner, form, and mind. 
You find us a degraded motley kind. 
Wonder no more, my friend! the cause is plain, 
And to lament the consequence is vain." 
(The Works of J. Hookham Frere, vol. ii. 1872, p. 334.) 



MANNER OF DEVELOPMENT. 29 

same parts of the body are affected in a closely analogous man- 
ner. This, has been proved in such full detail by Godron and 
Quatrefages, that I need here only refer to their works." Mon- 
strosities, which graduate Into slight variations, are likewise so 
similar in man and the lower animals, that the same classification 
and the same terms can be used for both, as has been shown by 
Isidore Geoffroy St.-Hilaire.^^ In my work on the variation of 
domestic animals, I have attempted to arrange in a rude fashion 
the laws of variation under the following heads:— The direct and 
definite action of changed conditions, as exhibited by all or nearly 
all the individuals of the same species, varying in the same man- 
ner under the same circumstances. The effects of the long-con- 
tinued use or disuse of parts. The cohesion of homologous parts. 
The variability of multiple parts. Compensation of growth; but 
of this law I have found no good instance in the case of man. The 
effects of the mechanical pressure of one part on another; as of 
the pelvis on the cranium of the infant in the womb. Arrests of 
development, leading to the diminution or suppression of parts. 
The reappearance of long-lost characters through reversion. And 
lastly, correlated variation. All these so-called laws apply equally 
to man and the lower animals; and most of them even to plants. 
It would be superfluous here to discuss all of them;" but several 
are so important, that they must be treated at considerable length. 

The direct and definite action of changed conditions. — This is a 
most perplexing subject. It cannot be denied that changed con- 
ditions produce some, and occasionally a considerable effect, on 
organisms of all kinds; and it seems at first probable that if suf- 
ficient time were allowed this would be the invariable result. 
But I have failed to obtain clear evidence in favor of this con- 
clusion; and valid reasons may be urged on the other side, at 
least as far. as the innumerable structures are concerned, which 
are adapted for special ends. There can, however, be no doubt 
that changed conditions induce an almost indefinite amount of 
fluctuating variability, by which the whole organization is ren- 
dered in some degree plastic. 

In the United States, above 1,000,000 soldiers, who served in 

1* Godron, 'De I'Espece,' 1859, torn. ii. livre 3. Quatrefages, 'Unite de 
I'Espece Humaine,' 1881. Also Lectures on Anthropology, given in the 
'Revue des Cours Scientifiques' 1866-1868. 

15 'Hist. Gen. et Part, des Anomalies de 1' Organisation' in three vol- 
umes, torn. i. 1832. 

i« I have fully discussed these laws in my 'Variation of Animals and 
Plants under Domestication,' vol. ii. chap. xxii. and xxiii. M. J. P. 
Durand has lately (1868) published a valuable essay 'De I'lnfluence des 
Milieux,' &c. He lays much stress, in the case of plants, on the nature 
of the soil. 



3d THE DESCENT OF MAN. 

the late war, were measured, and the States in which they were 
born and reared were recorded." From this astonishing number 
of observations it is proved that local influences of some kind 
act directly on stature; and we further learn that "the State 
"where the physical growth has in great measure taken place, 
"and the State of birth, which indicates the ancestry, seem to 
"exert a marked influence on the stature." For instance, it is 
established, "that residence in the 'Western States, during the 
"years of growth, tends to produce increase of stature." On the 
other hand, it is certain that with sailors, their life delays growth, 
as shown "by the great difference between the statures of soldiers 
"and sailors at the ages of seventeen and eighteen years." Mr. B. 
A. Gould endeavored to ascertain the nature of the influences 
which thus act on stature; but he arrived only at negative results, 
namely, that they did not relate to climate, the elevation of the 
land, soil, nor even "in any controlling degree" to the abundance 
or the need of the comforts of life. This latter conclusion is 
directly opposed to that arrived at by Villerme, from the statistics 
of the height of the conscripts in different parts of France. When 
we compare the differences in stature between the Polynesian 
chiefs and the lower orders within the same islands, or between 
the inhabitants of the fertile volcanic and low barren coral islands 
of the same ocean,^^ or again between the Fuegians on the eastern 
and western shores of their country, where the means of subsist- 
ence are very different, it is scarcely possible to avoid the con- 
clusion that better food and greater comfort do influence stature. 
But the preceding statements show how difiicult it is to arrive 
at any precise result. Dr. Beddoe has lately proved that, with 
the inhabitants of Britain, residence in towns and certain occupa- 
tions have a deteriorating influence on height; and he infers that 
the result is to a certain extent inherited, as is likewise the case 
in the United States. Dr. Beddoe further believes that wherever 
a "race attains its maximum of physical development, it rises 
"highest in energy and moral vigor."^" 

Whether external conditions produce any other direct effect 
on man is not known. It might have been expected that dif- 
ferences of climate would have had a marked influence, in as much 
as the lungs and kidneys are brought into activity under a low 

" 'Investigations in Military and Anthrop. Statistics,' &c. 1869, by B. 
A. Gould, p. 93, 107, 126, 131, 134. 

18 For the Polynesians, see Prichard's 'Physical Hist, of Mankind,' 
vol. V. 1847, p. 145, 283. Also Godron, 'De I'Espece,' torn. ii. p. 289. There 
is also a remarkable difference in appearance between the closely-allied 
Hindoos inhabiting the Upper Ganges and Bengal; see Elphinstone's 
'History of India,' vol. i. p. 324. 

19 'Memoirs, Anthropolog. Soc. vol. ill. 1867-1S69. pp. 561, 565, 567. 



MANNER OF DE;VEL0PMENT. 31 

temperature, and the liver and skin under a high one.^" It was 
formerly thought that the color of the skin and the character 
of the hair were determined hy light or heat; and although it 
can hardly be denied that some effect is thus produced, almost 
all observers now agree that the effect has been very small, even 
after exposure during many ages. But this subject will be more 
properly discussed when we treat of the different races of man- 
kind. With our domestic animals there are grounds for believing 
that cold and damp directly affect the growth of the hair; but 
I have not met with any evidence on this head in the case of 
man. 

Effects of the increased Use and Disuse of Parts. — It is well 
known that use strengthens the muscles in the individual, and 
complete disuse, or the destruction of the proper nerve, weakens 
them. When the eye is destroyed, the optic nerve often becomes 
atrophied. When an artery is tied, the lateral channels increase 
not only in diameter, but in the thickness and strength of their 
coats. When one kidney ceases to act from disease, the other 
increases in size, and does double work. Bones increase not 
only in thickness, but in length, from carrying a greater weight.^^ 
Different occupations, habitually followed, lead to changed pro- 
portions in various parts of the body. Thus it was ascertained 
by the United States Commission^- that the legs of the sailors 
employed in the late war were longer by 0.217 of an inch than 
those of the soldiers, though the sailors were on an average 
shorter men; whilst their arms were shorter by 1.09 of an inch, 
and therefore, out of proportion, shorter in relation to their lesser 
height. This shortness of the arms is apparently due to their 
greater use, and is an unexpected result: but sailors chiefly use 
their arms in pulling, and not in supporting weights. With 
sailors, the girth of the neck and the depth of the instep are 
greater, whilst the circumference of the chest, waist, and hips is 
less, than in soldiers. 

Whether the several foregoing modifications would become 
hereditary, if the same habits of life were followed during many 
generations, is not known, but it is probable. Rengger-^ attributes 
the thin legs and thick arms of the Payaguas Indians to successive 
generations having passed nearly their whole lives in canoes, 

20 Dr. Brakenridg-e, 'Theory of Diathesis,' 'Medical Times,' June 19 
and July 17, 1869. 

21 1 have given authorities for these several statements in my 'Varia- 
tion of Animals under Domestication,' vol. ii. pp. 297-300. Dr. Jaeger, 
"Ueber das Langenwachsthum der Knbchen," 'Jenaischen Zeitschrift,' 
B. V. Heft i. 

22 'Investigations,' &c. By B. A. Gould, 1869, p. 288. 

23 'Saugethiere von Paraguay,' 1830, s. 4. 



32 THE DESCENT OF MAN. 

with their lower extremities motionless. Other writers have 
come to a similar conclusion in analogous cases. According to 
Cranz,-* who lived for a long time with the Esquimaux, "the na- 
"tives believe that ingenuity and dexterity in seal-catching (their 
"highest art and virtue) is hereditary; there is really something 
*'in it, for the son of a celebrated seal-catcher will distinguish 
"himself, though he lost his father in childhood." But in this 
case it is mental aptitude, quite as much as bodily structure, which 
appears to be inherited. It is asserted that the hands of English 
laborers are at birth larger than those of the gentry."^ From the 
correlation which exists, at least in some cases,^° between the de- 
velopment of the extremities and of the jaws, it is possible that 
in those classes which do not labor much with their hands and 
feet, the jaws would be reduced in size from this cause. That they 
are generally smaller in refined and civilized men than in hard- 
working men or savages, is certain. But with savages, as Mr. 
Herbert Spencer^^ has remarked, the greater use of the jaws in 
chewing coarse, uncooked food, would act in a direct manner on 
the masticatory muscles, and on the bones to which they are at- 
tached. In infants, long before birth, the skin on the soles of 
the feet is thicker than on any other part of the body;^^ and it 
can hardly be doubted that this is due to the inherited effects of 
pressure during a long series of generations. 

It is familiar to every one that watchmakers and engravers 
are liable to be short-sighted, whilst men living much out of 
doors, and especially savages, are generally long-sighted.^^ Short- 
sight and long-sight certainly tend to be inherited.^" The infe- 
riority of Europeans, in comparison with savages, in eyesight and 
in the other senses, is no doubt the accumulated and transmitted 
effect of lessened use during many generations; for Rengger^^ 

2* 'History of Greenland,' Eng-. translat. 1767, vol. i. p. 280. 

25 'Intermarriage.' By Alex. Walker, 1838, p. 377. 

26 'The Variation of Animals under Domestication,' vol. i. p. 173. 

27 'Principles of Biology,' vol. i. p. 455. 

28 Paget, 'Lectures on Surgical Pathology,' vol. ii. 1853, p. 209. 

29 It is a singular and unexpected fact that sailors are inferior to 
landsmen in their mean distance of distinct vision. Dr. B. A. Gould 
('Sanitary Memoirs of the War of the Rebellion,' 1869, p. 530), has proved 
this to be the case; and he accounts for it by the ordinary range of 
vision in sailors being "restricted to the length of the vessel and the 
height of the masts." 

30 'The variation of Animals Under Domestication,' vol. i. p. 8. 

31 'Saugethiere von Paraguay,' s. 8, 10. I have had good opportuni- 
ties for observing the extraordinary power of eyesight in the Fuegians. 
See also Lawrence ('Lectures on Physiology,' &c., 1822, p. 404) on this 
same subject. M. Giraud-Teulon has recently collected ('Revue des 
Cours Scientifiques,' 1870, p. 625) a large and valuable body of evidence 
proving that the cause of short-sight, "C'est le travail assidu. de pres," 



MANNER OF DEVELOPMENT. 33 

states that he has repeatedly observed Europeans, who had been 
brought up and spent their whole lives with the wild Indians, 
who nevertheless did not equal them in the sharpness of their 
senses. The same naturalist observes that the cavities in the 
Skull for the reception of the several sense-organs are larger in 
the American aborigines than in Europeans; and this probably 
indicates a corresponding difference in the dimensions of the or- 
gans themselves. Blumenbach has also remarked on the large 
size of the nasal cavities in the skulls of the American aborigines, 
and connects this fact with their remarkably acute power of smell. 
The Mongolians of the plains of Northern Asia, according to 
Pallas, have wonderfully perfect senses; and Prichard believes 
that the great breadth of their skulls across the zygomas follows 
from their highly-developed sense-organs.^- 

The Quechua Indians inhabit the lofty plateaux of Peru; and 
Alcide d'Orbigny states'- that from continually breathing a highly 
rarefied atmosphere, they have acquired chests and lungs of ex- 
traordinary dimensions. The cells, also, of the lungs are larger 
and more numerous than in Europeans. These observations have 
been doubted; but Mr. D. Forbes carefully measured many Ay- 
maras, an allied race, living at the height of between 10,000 and 
15,000 feet; and he informs me^^ that they differ conspicuously 
from the men of all other races seen by him in the circumference 
and length of their bodies. In his table of measurements, the 
stature of each man is taken at 1000, and the other measurements 
are reduced to this standard. It is here seen that the extended 
arms of the Aymaras are shorter than those of Europeans, and 
much shorter than these of Negroes. The legs are likewise shorter; 
and they present this remarkable peculiarity, that in every Ay- 
mara measured, the femur is actually shorter than the tibia. On 
an average, the length of the femur to that of the tibia is as 211 
to 252; whilst in two Europeans, measured at the same time, the 
femora to the tibise were at 244 to 230; and in three Negroes as 
258 to 241. The humerus is likewise shorter relatively to the fore- 
arm. This shortening of that part of the limb which is nearest to 
the body, appears to be, as suggested to me by Mr. Forbes, a case 
of compensation in relation with the greatly increased length of 
the trunk. The Aymaras present some other singular points of 
structure, for instance, the very small projection of the heel. 

These men are so thoroughly acclimatized to their cold and 
lofty abode, that when formerly carried down by the Spaniards 



32 Prichard, 'Phys. Hist, of Mankind,' on the authority of Blumen- 
bach, vol. i. 1851, p. 311; for the statement by Pallas, vol. iv. 1844, p. 407. 

33 Quoted by Prichard, 'Researches into the Phys. Hist, of Mankind,' 
vol. V. p. 463. 

34 Mr. Forbes' valuable paper is now published in the 'Journal of 
the Ethnological Soc. of London,' new series, vol. ii. 1870, p. 193. 

4 



34 THE DESCENT OF MAN. 

to the low eastern plains, and when now tempted down by high 
wages to the gold-washings, they suffer a frightful rate of mor- 
tality. Nevertheless Mr. Forbes found a few pure families which 
had survived during two generations: and he observed that they 
still inherited their characteristic peculiarities. But it was mani- 
fest, even without measurement, that these peculiarities had all 
decreased; and on measurement, their bodies were found not to be 
so much elongated as those of the men on the high plateau; whilst 
their femora had become somewhat lengthened, as had their tibiae, 
although in a less degree. The actual measurements may be seen 
by consulting Mr. Forbes's memoir. From these observations, 
there can, I think, be no doubt that residence during many genera- 
tions at a great elevation tends, both directly and indirectly, to 
induce inherited modifications in the proportions of the body." 

Although man may not have been much modified during the 
latter stages of his existence through the increased or decreased 
use of parts, the facts now given show that his liability in this 
respect has not been lost; and we positively know that the same 
law holds good with the lower animals. Consequently we may 
infer that when at a remote epoch the progenitors of man were 
in a transitional state, and were changing from quadrupeds into 
bipeds, natural selection would probably have been greatly aided 
by the inherited effects of the increased or diminished use of the 
different parts of the body. 

Arrests of Development. — There is a difference between arrested 
development and arrested growth, for parts in the former state 
continue to grow whilst still retaining their early condition. 
Various monstrosities come under this head; and some, as a 
cleft-palate, are known to be occasionally inherited. It will 
suffice for our purpose to refer to the arrested brain-development 
of microcephalous idiots, as described in Vogt's memoir.^^ Their 
skulls are smaller, and the convolutions of the brain are less com- 
plex than in normal men. The frontal sinus, or the projection 
over the eyebrows, is largely developed, and the jaws are prog- 
nathous to an "effrayant" degree, so that these idiots somewhat 
resemble the lower types of mankind. Their intelligence, and 
most of their mental faculties, are extremely feeble. They 
cannot acquire the power of speech, and are wholly incapable of 
prolonged attention, but are much given to imitation. They are 
strong and remarkably active, continually gamboling and jumping 
about, and making grimaces. They often ascend stairs on all- 
fours; and are curiously fond of climbing up furniture or trees. 

35 Dr. Wilckens ('Landwirthschaft. Wochenblatt,' No. 10, 1869) has 
lately published an interesting Essay showing- how domestic animals, 
which live in mountainous regions, have their frames modified. 

36 'Memoire sur les Microcephales,' 1867, pp. 50, 125, 169, 171, 184-198. 



MANNER OF DEVELOPMENT. 35 

We are thus reminded of the delight shown by almost all boys 
in climbing trees; and this again reminds us how lambs and kids, 
originally alpine animals, delight to frisk on any hillock, however 
small. Idiots also resemble the lower animals in some other 
respects; thus several cases are recorded of their carefully smell- 
ing every mouthful of food before eating it. One idiot is described 
as often using his mouth in aid of his hands, whilst hunting for 
lice. They are often filthy in their habits, and have no sense of 
decency; and several cases have been published of their bodies 
being remarkably hairy.'^ 

Reversion. —Many of the cases to be here given, might have 
been introduced under the last heading. When a structure is 
arrested in its development, but still continues growing, until it 
closely resembles a corresponding structure in some lower and 
adult member of the same group, it may in one sense be con- 
sidered as a case of reversion. The lower members in a group 
give us some idea how the common progenitor was probably con- 
structed; and it is hardly credible that a complex part, arrested 
at an early phase of embryonic development, should go on grow- 
ing so as ultimately to perform its proper function, unless it had 
acquired such power during some earlier state of existence, when 
the present exceptional or arrested structure was normal. The 
simple brain of a microcephalous idiot, in as far as it resembles 
that of an ape, may in this sense be said to offer a case of rever- 
sion.^^ There are other cases which come more strictly under our 

87 Prof. Laycock sums up the character of brute-like idiots by calling- 
them "theroid;" 'Journal of Mental Science,' July, 1863. Dr. Scott ('The 
Deaf and Dumb,' 2nd edit., 1870, p. 10) has often observed the imbecile 
smelling- their food. See, on Uiis same subject, and on the hairiness 
of idiots. Dr. Maudsley, 'Body and Mind,' 1870, pp. 46-51. Pinei has also 
given a striking case of hairiness in an idiot. 

38 In my 'Variation of Animals under Domestication' (vol. ii. p. 57), 
I attributed the not very rare cases of supernumerary mammae in 
women to reversion. I was led to this as a probable conclusion, by the 
additional mammae being- g-enerally placed symmetrically on the 
breast; and more especially from one case, in which a single efficient 
mamma occurred in the inguinal region of a woman, the daughter of 
another woman with supernumerary mammae. But I now find (see, 
for instance. Prof. Preyer, 'Der Kampf um das Dasein,' 1859, s. 45) that 
mammae erraticae occur in other situations, as on the back, in the 
armpit, and on the thigh; the mammae in this latter instance having 
given so much milk that the child was thus nourished. The probability 
that the additional mammae are due to reversion is thus much weak- 
ened; nevertheless it still seems to me probable, because tv/o pairs 
are often found symmetrically on the breast; and of this I myself 
have received information in several cases. It is well known that some 
Lemurs normally have two pairs of mammae on the breast. Five 
cases have been recorded of the presence of more than a pair of mam- 



3^ THE DESCENT OF MAN. 

present head of reversion. Certain structures, regularly occurring 
in tlie lower members of the group to which man belongs, occa- 
sionally make their appearance in him, though not found in the 
normal human embryo; or, if normally present in the human 
embryo, they become abnormally developed, although in a manner 
which is normal in the lower members of the group. These re- 
marks will be rendered clearer by the following illustrations. 

In various mammals the uterus graduates from a double organ, 
with two distinct orifices and two passages, as in the marsupials, 
into a single organ, which is in no way double, except from 
having a slight internal fold, as in the higher apes and man. 

mae (of course rudimentary) in the male sex of mankind; see 'Journal 
of Anat. and Physiology,' 1872, p. 56, for a case given by Dr. Handj^side, 
in which two brothers exhibited this peculiarity; see also a paper by 
Dr. Bartels in 'Reichert's and du Bois-Reymond's Archiv.,' 1872, p. 304. 
In one of the cases alluded to by Dr. Bartels, a man bore five mam- 
mae, one being- medial and placed above the navel; Meckel von Hems- 
bach thinks that this latter case is illustrated by a medial mamma 
occurring in certain Cheiroptera. On the whole we may well doubt if 
additional mammae v/ould ever have been developed in both sexes of 
mankind, had not his early progenitors been provided with more than 
a single pair. 

In the above work (vol. ii. p. 12), I alSo attributed, though with much 
hesitation, the frequent cases of polydactylism in men and various ani- 
mals to reversion. I was partly led to this through Prof. Owen's state- 
ment, that some of the Ichthyopterygia possess more than five digits, 
and therefore, as I supposed, had retained a primordial condition; but 
Prof. Gegenbaur ('Jenaischen Zeitschrift,' B. v. Heft 3, s. 341), dis- 
putes Owen's conclusion. On the other hand, according to the opinion 
lately advanced by Dr. Gunther, on the paddle of Ceratodus, which is 
provided with articulated bony rays on both sides of a central chain of 
bones, there seems no great difficulty in admitting that six or more 
digits on one side, or on both sides, might reappear through reversion. 
I am informed by Dr. Zouteveen that there is a case on record of a 
man having twenty-four fingers and twenty-four toes! I v/as chiefly 
led to the conclusion that the presence of supernumerary digits might 
be due to reversion from the fact that such digits, not only are strongly 
inherited but, as I then believed, had the power of regrowth a^ter 
amputation, like the norm.al digits of the lower vertebrata. But I have 
explained in the Second Edition of my Variation under Domestication 
why I now place little reliance on the recorded cases of such regrowth. 
Nevertheless it deserves notice, in as much as arrested developm^ent 
and reversion are intimately related processes; that various structures 
m an embryonic or arrested condition, such as a cleft palate, bifid 
uterus, &c., are frequently accompanied by polydactylism. This has 
been strongly insisted on by Meckel and Isidore Geoffrey St. Hilaire. 
But at present it is the safest course to give up altogether the idea 
that there is any relation between the development of supernumerary 
digits and reversion to some lowly organized progenitor of man. 



MANNER OF DEVELOPMENT. 37 

The rodents exhibit a perfect series of gradations between these 
two extreme states. In all mammals the uterus is developed frons 
two simple primitive tubes, the inferior portions of which form 
the cornua; and it is, in the words of Dr. Parre, "by the coa- 
"lescence of the two cornua at their lower extremities that the 
"body of the uterus is formed in man; while in those animals 
"in which no middle portion of body exists, the cornua remain 
"un-united. As the development of the uterus proceeds, the two 
"cornua become gradually shorter, until at length they are losty 
"or, as it were, absorbed into the body of the uterus." The angler 
of the uterus are still produced into cornua, even in animals aa 
high up in the scale as the lower apes and lemurs. 

Now in women, anomalous cases are not very infrequent, in 
which the mature uterus is furnished with cornua, or is partially 
divided into two organs; and such cases, according to Owen, 
repeat "the grade of concentrative development," attained by 
certain rodents. Here perhaps we have an instance of a simple 
arrest of embryonic development, with subsequent growth and 
perfect functional development; for either side of the partially 
double uterus is capable of performing the proper office of 
gestation. In other and rarer cases, two distinct uterine cavities 
are formed, each having its proper orifice and passage.^ No 
such stage is passed through during the ordinary development 
of the embryo, and it is difficult to believe, though perhaps not 
impossible, that the two simple, minute, primitive tubes should 
know how (if such an expression may be used) to grow into two 
distinct uteri, each with a well-constructed orifice and passage^ 
and each furnished with numerous muscles, nerves, glands and 
vessels, if they had not formerly passed through a similar course 
of development, as in the case of existing marsupials. No one 
will pretend that so perfect a structure as the abnormal double 
uterus in woman could be the result of mere chance. But the 
principle of reversion, by which a long-lost structure is called 
back into existence, might serve as the guide for its full develop- 
ment, even after the lapse of an enormous interval of time. 

Professor Canestrini, after discussing the foregoing and various 
analogous cases, arrives at the same conclusion as that just given. 
He adduces another instance, in the case of the malar bone,*" 

3» See Dr. A. Farre's well-known article in the 'Cyclopaedia of Anat- 
omy and Physiolog-y,' vol. v., 1859, p. 642. Ov/en, 'Anatomy of Verte- 
brates,' vol. iii., 1868, p. 687. Professor Turnier in 'Edinburgh Medical 
Journal,' February, 1865. 

*° 'Annuario della Soc. dei Naturalist! in Modena,' 1867, p. 83. Prof. 
Canestrini g-ives extracts on this subject fro'm various authorities. 
Laurillard remarks, that as he has found a complete similarity in the 
form, proportions, aaid connection of the two malar bones in several 
human subjects and in certain apes, he cannot consider this disposition 
4 



gg THE DESCENT OF MAN. 

which, in some of the Quadrumana and other mammals, normally 
consists of two portions. This is its condition in the human fcetus 
when two months old; and through arrested development, it 
sometimes remains thus in man when adult, more especially in 
the lower prognathous races. Hence Canestrini concludes that 
some ancient progenitor of man must have had this bone nor- 
mally divided into two portions, which afterwards became fused 
together. In man the frontal bone consists of a single piece, but 
in the embryo, and in children, and in almost all the lower mam- 
mals, it consists of two pieces separated by a distinct suture. This 
suture occasionally persists more or less distinctly in man after 
maturity; and more frequently in ancient than in recent crania, 
especially, as Canestrini has observed, in those exhumed from 
the Drift, and belonging to the brachycephalic type. Here again 
he comes to the same conclusion as in the analogous case of the 
malar bones. In this, and other instances presently to be given, 
the cause of ancient races approaching the lower animals in 
certain characters more frequently than do the modern races, 
appears to be, that the latter stand at a somewhat greater distance 
in the long line of descent from their early semi-human progeni- 
tors. 

Various other anomalies in man, more or less analogous to the 
foregoing, have been advanced by different authors, as cases of 
reversion; but these seem not a little doubtful, for we have to 
descend extremely low in the mammalian series, before we find 
such structures normally present.*^ 



of the parts as simply accidental. Another paper on this same anomaly 
has been published by Dr. Saviotti in the 'Gazetta delle Cliniche' Turin, 
1871, where he says that traces of the division may be detected in about 
two per cent, of adult skulls; he silso remarks that it more frequently 
occurs in prog-nathous skulls, not of the Aryan race, than in others. 
See also G. Delorenzi on the same subject; *Tre nuovi casi d' anomalia 
deir osso malare,' Torino, 1872. Also, E. Morselli, 'Sopra una rara 
anomalia dell' osso malare,' Modena, 1872. Still more recently Gruber 
has written a pamphlet on the division of this bone. I give these 
references because a reviewer, without any grounds or scruples, has 
thrown doubts on my statements. 

^ A whole series of cases is given by Isid. Geoffrey St.-Hilaire, 'Hist, 
des Anomalies,' torn. iii. p. 437. A reviewer ('Journal of Anat. and 
Physiolog-y,' 1871, p. 366) blames me much for not having' discussed the 
numerous cases, which have been recorded, of various parts arrested in 
their development. He says that, according- to my theory, "every tran- 
"sient condition of an org^an, during- its development, is not only a 
"means to an end, but once was an end in itself." This does not seem to 
me necessarily to hold good. Why should not variations occur during 
an early period of development, having no relation to reversion; yet 
such variations might be preserved and accumulated, if In any wa.y ser- 
viceable, for instance, in shortening and simplifying the course of de* 



MANNER OF DEVELOPMENT. 39 

In man, the canine teeth are perfectly efficient instruments for 
mastication. But their true canine character, as Owen*- remarks, 
"is indicated by the conical form of the crown, which terminates 
"in an obtuse point, is convex outward and flat or sub-concave 
"within, at the base of which surface there is a feeble prominence. 
"The conical form is best expressed in the Melanian races, espe- 
"cially the Australian. The canine is more deeply implanted, 
"and by a stronger fang than the incisors." Nevertheless, this 
tooth no longer serves man as a special weapon for tearing his 
enemies or prey; it may, therefore, as far as its proper function 
is concerned, be considered as rudimentary. In every large col- 
lection of human skulls some may be found, as Hackel*^ observes, 
with the canine teeth projecting considerably beyond the others 
in the same manner as in the anthropomorphous apes, but in a 
less degree. In these cases, open spaces between the teeth in 
the one jaw are left for the reception of the canines of the opposite 
jaw. An interspace of this kind in a Kaffir skull, figured by Wag- 
ner, is surprisingly wide." Considering how few are the ancient 
skulls which have been examined, compared to recent skulls, it 
is an interesting fact that in at least three cases the canines pro- 
ject largely; and in the Naulette jaw they are spoken of as enor- 
mous.*^ 

Of the anthropomorphous apes the males alone have their 
canines fully developed; but in the female gorilla, and in a less 
degree in the female orang, these teeth project considerably beyond 
the others; therefore the fact, of which I have been assured, 
that women sometimes have considerably projecting canines, is 
no serious objection to the belief that their occasional great de- 
velopment in man is a case of reversion to an ape-like progenitor. 
He who rejects with scorn the belief that the shape of his own 
canines, and their occasional great development in other men, 
are due to our early forefathers having been provided with these 
formidable weapons, will probably reveal, by sneering, the line of 
his descent. For though he no longer intends, nor has the power, 
to use these teeth as weapons, he will unconsciously retract his 
"snarling muscles" (thus named by Sir C. Bell),*^ so as to expose 
them ready for action, like a dog prepared to fight. 



velopment? And again, why should not injurious abnormalities, such 
as atrophied or hypertrophied parts, which have no relation to a for- 
mer state of existence, occur at an early period, as well as during- 
maturity? 

*2 'Anatomy of Vertebrates,' vol. iii. 1868, p. 323. 

^ 'Generelle Morphologic,' 1886, B. ii. s. civ. 

** Carl Vogt's 'Lectures on Man,' Eng. translat. 1864, p. 151. 

*^ C. Carter Blake, on a jaw from La Naulette, 'Anthropolog. Review,' 
1867, p. 295. Schaaffhausen, ibid. 1868, p. 426. 

*« 'The Anatomy of Expression,' 1844, pp. 110, 131. 



40 THE DESCENT OF MAN. 

Many muscles are occasionally developed in man, which ai-ts 
proper to the Quadrumana or other mammals. Professor Vlaco- 
vich^' examined forty male subjects, and found a muscle, called 
by him the ischio-pubic, in nineteen of them; in three others 
there was a ligament which represented this muscle; and in the 
remaining eighteen no trace of it. In only two out of thirty 
female subjects was this muscle developed on both sides, but in 
three others the rudimentary ligament was present. This muscle, 
therefore, appears to be much more common in the male than in 
the female sex; and on the belief in the descent of man from 
some lower form, the fact is intelligible; for it has been detected 
in several of the lower animals, and in all of these it serves 
exclusively to aid the male in the act of reproduction. 

Mr. J. Wood, in his valuable series of papers,*' has minutely 
described a vast number of muscular variations in man, which 
resemble normal structures in the lower animals. The muscles 
which closely resemble those regularly present in our nearest 
allies, the Quadrumana, are too numerous to be here even speci- 
fied. In a single male subject, having a strong bodily frame, and 
well-formed skull, no less than seven muscular variations were 
observed, all of which plainly represented muscles proper to 
various kinds of apes. This man, for instance, had on both sides 
of his neck a true and powerful "levator claviculse," such as is 
found in all kinds of apes, and which is said to occur in about 
one out of sixty human subjects.*^ Again, this man had "a special 
"abductor of the metatarsal bone of the fifth digit, such as Pro- 
"fessor Huxley and Mr. Flower have shown to exist uniformly 
"in the higher and lower apes." I will give only two additional 
cases; the acromio-basilar muscle is found in all mammals below 
man, and seems to be correlated with a quadrupedal gait,^° and 
it occurs in about one out of sixty human subjects. In the lower 

*'7 Quoted by Prof. Canestrini in the 'Annuario,' &c., 1867, p. 90. 

48 These papers deserve careful study by any one who desires to learn 
how frequently our muscles vary, and in varying- come to resemble 
those of the Quadrumana. The following references relate to the few 
points touched on in my text: 'Proc. Poyal Soc. vol. xiv. 1865, pp. 379- 
384; vol. XV. 1866, pp. 241, 242; vol. xv. 1867, p. 544; vol. xvi. 1868, p. 524. 
I may here add that Dr. Murie and Mr. St. George Mivart have shown 
in their Memoir on the Lemuroidea ('Transact. Zoolog. Soc' vol. vii. 
1869, p. 96), how extraordinarily variable some of the muscles are in 
these animals, the lowest members of the Primates. Gradations, also, 
in the muscles leading to structures found in animals still lower in 
the scale, are numerous in the Lem.uroidea. 

49 See also Prof, Macalister in 'Proc. R. Irish Academy,' vol. x. 1868, 
p. 124. 

K> Mr. Champneys in 'Journal of Anat. and Phys.' Nov., 1871, p. 178. 



MANNER OF DEVELOPMENT. 41 

extremities Mr. Bradley^^ found an abductor ossis metatarsi quinti 
in both feet of man; this muscle had not up to that time been 
recorded in mankind, but is always present in the anthropomor- 
phous apes. The muscles of the hands and arms— parts of which 
are so eminently characteristic of man — are extremely liable to 
vary, so as to resemble the corresponding muscles in the lower 
animals.'- Such resemblances are either perfect or imperfect; 
yet in the latter case they are manifestly of a transitional nature. 
Certain variations are more common in man, and others in 
woman, without our being able to assign any reason. Mr. Wood, 
after describing numerous variations, makes the following preg- 
nant remark: "Notable departures from the ordinary type of the 
"muscular structures run in grooves or directions, which must 
"be taken to indicate some unknown factor, of much importance 
"to a comprehensive knowledge of general and scientific anat- 
omy."" 

That this unknown factor is reversion to a former state of 
existence may be admitted as in the highest degree probable.^* 
It is quite incredible that a man should through mere accident 
abnormally resemble certain apes in no less than seven of his 
muscles, if there had been no genetic connection between them. 



Bi 'Journal of Anat. and Phys.' May, 1872, p. 421. 

^2 Prof. Macalister (ibid. p. 121) has tabulated his observations, and 
finds that muscular abnormalities are most frequent in the fore-arms, 
secondly, in the face, thirdly, in the foot, &c. 

S3 The Rev. Dr. Haughton, after giving- ('Proc. R. Irish Academy,' 
June 27, 1864, p. 715), a remarkable case of variation in the human 
flexor pollicis longus, adds, "This remarkable example shows that man 
"may sometimes possess the arrangement of tendons of thumb and 
"fingers characteristic of the macaque; but whether such a case should 
"be regarded as a macaque passing upwards into a man, or a man 
"passing downward into a macaque, or as a congenital freak of nature, 
"I cannot undertake to say." It is satisfactory to hear so capable 
an anatomist, and so embittered an opponent of evolutionism, admit- 
ting even the possibility of either of his first propositions. Prof. Mac- 
alister has also described ('Proc. R. Irish Acad.* vol. x. 1864, p. 138) 
variations in the flexor pollicis longus, remarkable from their rela- 
tions to the same muscle in the Quadrumana. 

^ Since the first edition of this book appeared, Mr. Wood has pub- 
lished another memoir in the 'Phil. Transactions,' 1870, p. 83, on the 
varieties of the muscles of the human neck, shoulder, and chest. He 
here shows how extremely variable these muscles are, and how often 
and how closely the variations resemble the normal muscles of the 
lower animals. He sums up by remarking, "It will be enough for my 
"purpose if I have su-cceeded in showing the more important forms 
"which, when occurring as varieties in the human subject, tend to ex- 
"hibit in a sufiiciently marked manner what may be considered as 
"proofs and examples of the Darwinian principle of reversion or law 
"of inheritance, in this department of anatomical scienca" 



42 :fHE DESCENT OP MAN. 

On the other hand, if man is descended from some ape-like crea- 
ture, no valid reason can be assigned why certain muscles should 
not suddenly reappear after an interval of many thousand genera- 
tions, in the same manner as with horses, asses, and mules, dark- 
colored stripes suddenly reappear on the legs and shoulders, after 
an interval of hundreds, or more probably of thousands of genera- 
tions. 

These various cases of reversion are so closely related to those 
of rudimentary organs given in the first chapter, that many of 
them might have been indifferently introduced either there or 
here. Thus a human uterus furnished with cornua may be said 
to represent, in a rudimentary condition, the same organ in its 
normal state in certain mammals. Some parts which are rudi- 
mentary in man, as the os coccyx in both sexes, and the mammse 
in the male sex, are always present; whilst others, such as the 
supracondyloid foramen, only occasionally appear, and therefore 
might have been introduced under the head of reversion. These 
several reversionary structures, as well as the strictly rudi- 
mentary ones, reveal the descent of man from some lower form 
in an unmistakable manner. 

Correlated Variation. — In man, as in the lower animals, many 
structures are so intimately related, that when one part varies 
so does another, without our being able, in most cases, to assign 
any reason. We cannot say whether the one part governs the 
other, or whether both are governed by some earlier developed 
part. Various monstrosities, as I. Geoffroy repeatedly insists, are 
thus intimately connected. Homologous structures are particu- 
larly liable to change together, as we see on the opposite sides of 
the body, and in the upper and lower extremities. Meckel long 
ago remarked, that when the muscles of the arm depart from 
their proper type, they almost always imitate those of the leg; 
and so, conversely, with the muscles of the legs. The organs of 
sight and hearing, the teeth and hair, the color of the skin and of 
the hair, color and constitution, are more or less correlated.^^ 
Professor Schaaffhausen first drew attention to the relation ap- 
parently existing between a muscular frame and the strongly- 
pronounced supra-orbital ridges, which are so characteristic of 
the lower races of man. 

Besides the variations which can be grouped with more or 
less probability under the foregoing heads, there is a large class 
of variations which may be provisionally called spontaneous, for 
to our ignorance they appear to arise without any exciting cause. 
It can, however, be shown that such variations, whether consist- 

Es The authorities for these several statements are given in my 'Va- 
riation of Animals under Domestication,' vol. ii. pp. 820-335. 



MANNER OF DEVELOPMENT. 43 

ing of slight indwidual differences, or of strongly-marked and 
abrupt deviation? of structure, depend much more on '.he consti- 
tution of the organism than on the nature of the cov^ditions to 
which it has been subjected.^^ 

Rate of Increase. — Civilized populations have been known under 
favorable conditions, as in the United States, to double their 
numbers in twenty-five years; and, according to a calculation by 
Euler, this might occur in a little over twelve years.^^ At the 
former rate, the present population of the United States (thirty 
millions), would in 657 years cover the whole terraqueous globe 
so thickly, that four men would have to stand on each square 
yard of surface. The primary or fundamental check to the con- 
tinued increase of man is the difficulty of gaining subsistence, and 
of living in comfort. We may infer that this is the case from what 
we see, for instance, in the United States, where subsistence is 
easy, and there is plenty of room. If such means were suddenly 
doubled in Great Britain, our number would be quickly doubled. 
With civilized nations this primary check acts chiefly by restrain- 
ing marriages. The greater death-rate of infants in the poorest 
classes is also very important; as well as the greater mortality, 
from various dis'eases, of the inhabitants of crowded and miserable 
houses, at all ages. The effects of severe epidemics and wars 
are soon counterbalanced, and more than counterbalanced, in 
nations placed under favorable conditions. Emigration also comes 
in aid as a temporary check, but, with the extremely poor classes, 
not to any great extent. 

There is reason to suspect, as Malthus has remarked, that the 
reproductive power is actually less in barbarous, than in civilized 
races. We know nothing positively on this head, for with savages 
no census has been taken; but from the concurrent testimony of 
missionaries, and of others who have long resided with such 
people, it appears that their families are usually small, and 
large ones rare. This may be partly accounted for, as it is be- 
lieved, by the women suckling their infants during a long time; 
but it is highly probable that savages, who often suffer much 
hardship, and who do not obtain so much nutritious food as 
civilized men, would be actually less prolific. I have shown in a 
former work,°^ that all our domesticated quadrupeds and birds, 
and all our cultivated plants, are more fertile than the cor- 
responding species in a state of nature. It is no valid objection to 



^ This whole subject has been discussed in chap, xxiii. vol. ii. of my 
'Variation of Animals and Plants under Domestication.' 

" See the ever memorable 'Essay on the Principle of Population,' by 
the Rev. T. Malthus, vol. i. 1826, p. 6, 517. 

°s 'Variation of Animals and Plants under Domestication,' vol. ii. 
pp. 111-113, 163. 



44 THE DESCENT OF MAN. 

this conclusion tliat animals suddenly supplied with an excess of 
food, or when grown very fat; and that most plants on sudden 
removal from very poor to very rich soil, are rendered more or 
less sterile. We might, therefore, expect that civilized men, 
who in one sense are highly domesticated, would be more prolific 
than wild men. It is also probable that the increased fertility 
of civilized nations would become, as with our domestic animals, 
an inherited character: it is at least known that with mankind 
a tendency to produce twins runs in families.^^ 

Notwithstanding that savages appear to be less prolific than 
civilized people, they would no doubt rapidly increase if their 
numbers were not by some means rigidly kept down. The San- 
tali, or hill-tribes of India, have recently afforded a good illustra- 
tion of this fact; for, as shown by Mr. Hunter,*'" they have in- 
creased at an extraordinary rate since vaccination has been intro- 
duced, other pestilences mitigated, and war sternly suppressed. 
This increase, however, would not have been possible had not 
these rude people spread into the adjoining districts, and worked 
for hire. Savages almost always marry; yet there is some pru- 
dential restraint, for they do not commonly marry at the earliest 
possible age. The young men are often required to show that 
they can support a wife; and they generally have first to earn 
the price of which to purchase her from her parents. With sav- 
ages the difficulty of obtaining subsistence occasionally limits 
their number in a much more direct manner than with civilized 
people, for all tribes periodically suffer from severe famines. At 
such times savages are forced to devour much bad food, and 
their health can hardly fail to be injured. Many accounts have 
been published of their protruding stomachs and emaciated limbs 
after and during famines. They are then, also, compelled to 
wander much, and, as I was assured in Australia, their infants 
perish in large numbers. As famines are periodical, depending 
chiefly on extreme seasons, all tribes must fluctuate in number. 
They cannot steadily and regularly increase, as there is no arti- 
ficial increase in the supply of food. Savages, when hard pressed, 
encroach on each other's territories, and war is the result; but 
they are indeed almost always at war with their neighbors. They 
are liable to many accidents on land and water in their search for 
food; and in some countries they suffer much from the larger 
beasts of prey. Even in India, districts have been depopulated by 
the ravages of tigers. 

Malthus has discussed these several checks, but he does not lay 
stress enough on what is probably the most important of all, 

^» Mr, Sedgwick, 'British and Foreign Medico-Chirurg. Review, July, 
1863, p. 170. 
«o 'The Annals of Rural Bengal,' by W. W. Hunter, 1868, p. 259. 



MANNER OF DEVELOPMENT. 45 

namely infanticide, especially of female infants, and the habit of 
procuring abortion. These practices now prevail in many quar- 
ters of the world; and infanticide seems formerly to have pre- 
vailed, as Mr. M'Lennan"' has shown, on a still more extensive 
scale. These practices appear to have originated in savages recog- 
nizing the difficulty, or rather the impossibility of supporting all 
the iiifants that are born. Licentiousness may also be added to 
the foregoing checks; but this does not follow from failing means 
of subsistence; though there is reason to believe that in some cases 
(as in Japan) it has been intentionally encouraged as a means of 
keeping down the population. 

If we look back to an extremely remote epoch, before man had 
arrived at the dignity of manhood, he would have been guided 
more by instinct and less by reason than are the lowest savages 
at the present time. Our early semi-human progenitors would not 
have practiced infanticide or polyandry; for the instincts of the 
lower animals are never so perverted^- as to lead them regularly to 
destroy their cwn offspring, or to be quite devoid of jealousy. 
There would have been no prudential restraint from marriage, and 
the sexes would have freely united at an early age. Hence the 
progenitors of man would have tended to increase rapidly; but 
checks of some kind, either periodical or constant, must have 
kept down their numbers, even more severely than with existing 
savages. What the precise nature of these checks were, we can- 
not say, any more than with most other animals. We know that 
horses and cattle, which are not extremely prolific animals, when 
first turned loose in South America, increased at an enormous rate. 
The elephant, the slowest breeder of all known animals, would in 
a few thousand years stock the whole world. The increase of 
every species of monkey must be checked by some means; but not, 
as Brehm remarks, by the attacks of beasts of prey. No one will 
assume that the actual power of reproduction in the wild horses 
and cattle of America, was at first in any sensible degree in- 

61 'Primitive Marriage,' 1S65. 

•52 A writer in the 'Spectator' (March 12th, 1871, p. 320) comments as 
follows on this passag-e:— "Mr. Darwin finds himself compelled to re- 
"introduce a new doctrine of the fall of man. He shows that the 
"instincts of the higher animals are far nobler than the habits of sav- 
"ag-e races of men, and he finds himself, therefore, compelled to re- 
"introduce,— in a form of the substantial orthodoxy of which he 
"appears to be quite unconscious,— and to introduce as a scientific 
"hypothesis the doctrine that man's gain of knowledge was the cause 
"of a temporary but long-enduring moral deterioration as indicated by 
"the many foul customs especially as to marriage, of savage tribes. 
"What does the Jewish tradition of the moral degeneration of man 
"through his snatching at a knowledge forbidden him by his highest 
"instinct assert beyond this?" 



46 THE DESCENT OF MAN. 

creased; or that, as each district became fully stocked, this same 
power was diminished. No doubt in this case, and in all others, 
many checks concur, and different checks under different circum- 
stances; periodical dearths, depending on unfavorable seasons, 
being probably the most important of all. So it will have been 
Y/ith the early progenitors of man. 

Natural Selection. —We have now seen that man is variable in 
body and mind; and that the variations are induced, either di- 
rectly or indirectly, by the same general causes, and obey the 
same general laws, as with the lower animals. Man has spread 
widely over the face of the earth, and must have been exposed, 
during his incessant migrations,°^ to the most diversified condi- 
tions. The inhabitants of Tierra del Fuego, the Cape of Good 
Hope, and Tasmania in the one hemisphere, and of the Arctic 
regions in the other, must have passed through many climates, 
and changed their habits many times, before they reached their 
present homes.''* The early progenitors of man must also have 
tended, like all other animals, to have increased beyond their 
means of subsistence; they must, therefore occasionally have been 
exposed to a struggle for existence, and consequently to the rigid 
law of natural selection. Beneficial variations of all kinds will 
thus, either occasionally or habitually, have been preserved, and 
injurious ones eliminated. I do not refer to strongly-marked de- 
viations of structure, which occur only at long intervals of time, 
but to mere individual differences. We know, for instance, that 
the muscles of our hands and feet, which determine our powers of 
movement, are liable, like those of the lower animals,^ to incessant 
variability. If then the progenitors of man inhabiting any dis- 
trict, especially one undergoing some change in its conditions, 
were divided into two equal bodies, the one half which included all 
the individuals best adapted by their powers of movement for gain- 
ing subsistence, or for defending themselves, would on an average 
survive in greater numbers, and procreate more offspring than the 
other and less well endowed half. 
r" Man in the rudest state in which he now exists is the most domi- 
nant animal that has ever appeared on this earth. He has spread 
I more widely than any other highly organized form; and all others 
xhave yielded before him. He manifestly owes this immense superi- 

«3 See some g-ood remarks to this effect by W. Stanley Jevons, "A 
"Deduction from. Darwin's Theory," 'Nature,' 1869, p. 231. 

«* Latham, 'Man and his Migrations,' 1851, p. 135. 

«" Messrs. Murie and Mivart in their 'Anatomy of the Lemuroidea' 
('Transact. Zoolog. Soc. vol. vii. 1869, pp. 96-98) say, "some muscles are 
"so irregular in their distribution that they cannot be well classed in 
"any of the above groups." These muscles differ even on the oppo- 
site sides of the same individual. 



MANNER OF DEVELOPMENT. 47 

ority to his intellectual faculties, to his social habits, which lead 
him to aid and defend his fellows, and to his corporeal structure. 
The supreme importance of these characters has been proved by 
the final arbitrament of the battle for life. Through his powers 
of intellect, articulate language has been evolved; and on this his 
wonderful advancement has mainly depended. As Mr. Chauncey 
Wright remarks:®^ "a psychological analysis of the faculty of lan- 
"guage shows, that even the smallest proficiency in it might re- 
"quire more brain power than the greatest proficiency in any other 
"direction." He has invented and is able to use various weapons, 
tools, traps, &c., with which he defends himself, kills or catches 
prey, and otherwise obtains food. He has made rafts or canoes 
for fishing or crossing over to neighboring fertile islands. He 
has discovered the art of making fire, by which hard and stringy 
roots can be rendered digestible, and poisonous roots or herbs 
innocuous. This discovery of fire, probably the greatest ever 
made by man, excepting language, dates from before the dawn of 
history. These several inventions, by which man in the rudest 
state has become so preeminent, are the direct results of the devel- 
opment of his powers of observation, memory, curiosity, imagina- 
tion, and reason. I cannot, therefore, understand how it is that 
Mr. Wallace" maintains, that "natural selection could only have 
"endowed the savage with a brain a little superior to that of an 
"ape." 

Although the intellectual powers and social habits of man are 
of paramount importance to him, we must not underrate the im- 
portance of his bodily structure, to which subject the remainder of 
this chapter will be devoted; the development of the intellectual 
and social or moral faculties being discussed in a later chapter. 

Even to hammer with precision is no easy matter, as every one 



«8 Limits of Natural Selection, 'North American Review,' Oct, 1870, 
p. 295. 

67 'Quarterly Review,' AprO, 1869, p. 392. This subject is more fully 
discussed in Mr. Wallace's 'Contributions to the Theory of Natural 
Selection,' 1870, in which all the essays referred to in this work are 
republished. The 'Essay on Man' has been ably criticized by Prof. 
Claparede, one of the most disting-uished zoologists in Europe, in an 
article published in the 'Bibliotheque Universelle,* June, 1870. The re- 
mark quoted in my text will surprise every one who has read Mr. 
Wallace's celebrated paper* on 'The Origin of Human Races deduced 
from the Theory of Natural Selection,' originally published in the 'An- 
thropological Review,' May, 1864, p. clviii. I cannot here resist quot- 
ing a most just remark by Sir J. Lubbock ('Prehistoric Times,' 18G5, 
p. 479) in reference to this paper, namely, that Mr. Wallace, "with 
"characteristic unselfishness, ascribes it (i. e. the idea of natural selec- 
"tion) unreservedly to Mr. Darwin, althoug-h, as is well known, he 
"struck out the idea independently, and published it, though not with 
"the same elaboration, at the same time." 



4g THE DESCENT OF MAN. 

who has tried to learn carpentry will admit. To throw a stone 
with as true an aim as a Fuegian in defending himself, or in kill- 
ing birds, requires the most consummate perfection in the cor- 
related action of the muscles of the hand, arm, and shoulder, and, 
further, a fine sense of touch. In throwing a stone or spear, and 
in many other actions, a man must stand firmly on his feet, and 
this again demands the perfect co-adaptation of numerous mus- 
cles. To chip a flint into the rudest tool, or to form a barbed spear 
or hook from a bone, demands the use of a perfect hand; for, as 
a most capable judge, Mr. Schoolcraft,''^ remarks, the shaping frag- 
ments of stone into knives, lances, or arrow-heads, shows "ex- 
traordinary ability and long practice." This is to a great extent 
proved by the fact that primeval men practiced a division of labor; 
each man did not manufacture his own flint tools or rude pottery, 
but certain individuals appear to have devoted themselves to such 
work, no doubt receiving in exchange the produce of the chase. 
Archgeologists are convinced that an enormous interval of time 
elapsed before our ancestors thought of grinding chipped flints 
into smooth tools. One can hardly doubt, that a man-like animal 
who possessed a hand and arm sufficiently perfect to throw a stone 
with precision, or to form a flint into a rude tool, could, with suf- 
ficient practice, as far as mechanical skill alone is concerned* 
make almost anything which a civilized man can make. The 
structure of the hand in this respect may be compared with that of 
the vocal organs, which in the apes are used for uttering various 
signal-cries, or, as in one genus, musical cadences; but in man the 
closely similar vocal organs have become adapted through the in- 
herited effects of use for the utterance of articulate language. 

Turning now to the nearest allies of men, and therefore to the 
best representatives of our early progenitors, we find that the 
hands of the Quadrumana are constructed on the same general 
pattern as our own, but are far less perfectly adapted for diver- 
sified uses. Their hands do not serve for locomotion so well as 
the feet of a dog; as may be seen in such monkeys as the chim- 
panzee and orang, which walk on the outer margins of the palms, 
or on the knuckles.''^ Their hands, however, are admirably adapt- 
ed for climbing trees. Monkeys seize thin branches or ropes, 
with the thumb on one side and the fingers and palm on the other, 
in the same manner as we do. They can thus also lift rather large 
objects, such as the neck of a bottle to their mouths. Baboons 
turn over stones, and scratch up roots with their hands. They 
seize nuts, insects, or other small objects with the thumb in oppo- 



«8 Quoted by Mr. Lawson Tait in his 'Law of Natural Selection,'— 
•Dublin Quarterly Journal of Medical Science,' Feb. 1869. Dr. Keller 
Is likewise quoted to the same effect. 

^^ Owen, 'Anatomy of Vertebrates,' vol, iii. p. 71. 



MANNER OF DEVELOPME2NT. 49 

sition to the fingers, and no doubt they thus extract eggs and the 
young from the nests of birds. American monkej^s beat the wild 
oranges on the branches until the rind is cracked, and then tear it 
off with the fingers of the two hands. In a wild state they break 
open hard fruits with stones. Other monkeys open mussel-shells 
with the two thumbs. With their fingers they pull out thorns and 
burs, and hunt for each other's parasites. They roll down stones, 
or throw them at their enemies: nevertheless, they are clumsy in 
these various actions, and, as I have myself seen, are quite unable 
to throw a stone with precision. 

It seems to me far from true that because "objects are grasped 
'^clumsily" by monkeys, "a much less specialized organ of pre- 
"hension" would have served them'° equally well with their pres- 
ent hands. On the contrary, I see no reason to doubt that more 
perfectly constructed hands would have been an advantage to 
them, provided that they were not thus rendered less fitted for 
climbirtg trees. We may suspect that a hand as perfect as that 
oi man would have been disadvantageous for climbing; for the 
most arboreal monkeys in the world, namely, Ateles in America, 
Colobus in Africa, and Hylobates in Asia, are either thumbless, or 
their toes partially cohere, so that their limbs are converted into 
mere grasping hooks.^^ 

As soon as some ancient member in the great series of the 
Primates came to be less arboreal, owing to a change in its man- 
ner of procuring subsistence, or to some change in the surround- 
ing conditions, its habitual manner of progression would have been 
modified r and thus it would have been rendered more strictly 
quadrupedal or bipedal. Baboons frequent hilly and rocky dis- 
tricts, and only from necessity climb high trees ;^2 and they have 
acquired almost the gait of a dog. Man alone has become a biped; 
and we can, I think, partly see how he has come to assume his 
erect attitude, which forms one of his most conspicuous charac- 
ters. Man could not have attained his present dominant position 
in the world without the use of his hands, which are so admirably 
adapted to act in obedience to his will. Sir C. BelF^ insists that 
"the hand supplies all instruments, and by its correspondence with 
"the intellect gives him universal dominion." But the hands and 



■^0 'Quarterly Review,' April, 1869, p. 392. 

■^1 In Hylobates syndactylus, as the name expresses, two of the toes 
reg-ularly cohere; and this, as Mr. Blyth informs me is occasionally 
the case with the toes of H. agilis, lar, and leuciscus. Colobus is 
strictly arboreal and extraordinarily active (Brehm, 'Thierleben,' B. 1, 
s. 50), but whether a better climber than the species of the allied gen- 
era, I do not know. It deserves notice that the feet of the sloths, the 
most arboreal animals in the world, are wonderfully hook-like. 

'2 Brehm, 'Thierleben,' B. i. s. 80. 

'3 "The Hand," &c. 'Bridgewater Treatise/ 1833, p. 38. 
5 



50 THE DESCENT OF MAN. 

arms could hardly have become perfect enough to have manu- 
factured weapons, or to have hurled stones and spears with a true 
aim, as long as they were habitually used for locomotion and for 
supporting the whole weight of the body, or, as before remarked, 
so long as they were especially fitted for climbing trees. Such 
rough treatment would also have blunted the sense of touch, on 
which their delicate use largely depends. From these causes 
alone it would have been an advantage to man to become a biped; 
but for many actions it is indispensable that the arms and whole 
upper part of the body should be free; and h© must for this end 
stand firmly on his feet. To gain this great advantage, the feet 
have been rendered fiat; and the great toe has been peculiarly 
modified, though this has entailed the almost complete loss of its 
power of prehension. It accords with the principle of the division 
of physiological labor, prevailing throughout the animal king- 
dom, that as the hands became perfected for prehension, the feet 
should have become perfected for support and locomotion. With 
some savages, however, the foot has not altogether lost its pre- 
hensile power, as shown by their manner of climbing trees, and of 
using them in other ways.^^ 

If it be an advantage to man to stand firmly on his feet and 
to have his hands and arms free, of which, from his pre-emi« 
nent success in the battle of life, there can be no doubt, then I 
can see no reason why it should not have been advantageous 
to the progenitors of man to have become more and more 
erect or bipedal. They would thus have been better able to de- 
fend themselves with stones or clubs, to attack their prey, 
or otherwise to obtain food. The best built individuals 
would in the long run have succeeded best, and have sur- 
vived in larger numbers. If the gorilla and a few allied 
forms had become extinct, it might have been argued, with 
great force and apparent truth, that an animal could not have 
been gradually converted from a quadruped into a biped, as all 
the individuals in an intermediate condition would have been 
miserably ill-fitted for progression. But we know (and this is well 
worthy of refiection) that the anthropomorphous apes are now 
actually in an intermediate condition; and no one doubts that 
they are on the whole well adapted for their conditions of life. 
Thus the gorilla runs with a sidelong shambling gait, but more 

'* Hackel has an excellent discussion on the steps by which man be- 
came a biped: 'Naturliche Schopfung-sgeschichte,' 1868, s. 507, Dr. 
Buchner ('Conferences sur la Theorie Darwinienne,' 1869, p. 135) has 
given good cases of the use of the foot as a prehensile organ by man; 
ajad has also written on the manner of progression of the higher apes, 
lo which I allude in the following paragraph: see also Owen ('Anat- 
omy of Vertebrates,' vol. iii. p. 71) on this latter subject. 



MANNER OF DEVELOPMENT. 51 

commonly progresses by resting on its bent hands. The long- 
armed apes occasionally use their arms like crutches, swinging 
their bodies forward between them, and some kinds of Hylobates, 
without having been taught, can walk or run upright with tolerable 
quickness; yet they move awkwardly, and much less securely than 
man. We see, in short, in existing monkeys a manner of progres- 
sion intermediate between that of a quadruped and a biped; but, 
as an unprejudiced judge'^ insists, the anthropomorphous apes 
approach in structure more nearly to the bipedal than to the quad- 
rupedal type. 

As the progenitors of man became more and more erect, with 
their hands and arms more and more modified for prehension and 
other purposes, with their feet and legs at the same time trans- 
formed for firm support and progression, endless other changes of 
structure would have become necessary. The pelvis would have 
to be broadened, the spine peculiarly curved, and the head fixed in 
an altered position, all which changes have been attained by man. 
Prof. Schaaffhausen"*' maintains that "the powerful mastoid proc- 
"esses of the human skull are the result of his erect position;" 
and these processes are absent in the orang, chimpanzee, &c., and 
are smaller in the gorilla than in man. Various other structures, 
which appear connected with man's erect position, might here 
have been added. It is very difficult to decide how far these cor- 
related modifications are the result of natural selection, and how 
far of the inherited effects of the increased use of certain parts, or 
of the action of one part on another. No doubt these means of 
change often co-operate: thus when certain muscles, and the 
crests of bone to which they are attached, become enlarged by ha- 
bitual use, this shows that certain actions are habitually per- 
formed and must be serviceable. Hence the individuals which 
performed them best, would tend to survive in greater numbers. 

The free use of the arms and hands, partly the cause and partly 
the result of man's erect position, appears to have led in an in- 
direct manner to other modifications of structure. The early male 
forefathers of man were, as previously stated, probably furnished 
with great canine teeth; but as they gradually acquired the habit 
of using stones, clubs, or other weapons, for fighting with their 
enemies or rivals, they would use their jaws and teeth less and 
less. In this case, the jaws, together with the teeth, would be- 
come reduced in size, as we may feel almost sure from innumerable 
analogous cases. In a future chapter we shall meet with a closely 

■^ Prof . Broca, La Constitution des Vertebres caudales; 'La Revue 
d'Anthropolog-ie,' 1872, p. 26 (separate copy). 

'« 'On the Primitive Form of the Skull,' translated in 'Anthropolog- 
ical Review,' Oct. 1868, p. 428. Owen ('Anatomy of Vertebrates,' vol. ii. 
1866, p. 551) on the mastoid processes in the higher apes. 



52 THE DESCENT OP MAN. 

parallel case, in the reduction or complete disappearance of the 
canine teeth in male ruminants, apparently in relation with the 
development of their horns; and in horses, in relation to their 
habit of fighting with their incisor teeth and hoofs. 

In the adult male anthropomorphous apes, as Riitimeyer,^^ and 
others, have insisted, it is the effect on the skull of the great de- 
velopment of the jaw-muscles that causes it to differ so greatly in 
many respects from that of man, and has given to these animals 
"a truly frightful physiognomy." Therefore, as the jaws and 
teeth in man's progenitors gradually became reduced in size, the 
adult skull would have come to resemble more and more that of 
existing man. As we shall hereafter see, a great reduction of the 
canine teeth in the males would almost certainly affect the teeth 
of the females through inheritance. 

As the various mental faculties gradually developed themselves 
the brain would almost certainly become larger. No one, I pre- 
sume, doubts that the large proportion which the size of man's 
brain bears to his body, compared to the same proportion in the 
gorilla or orang, is closely connected with his higher mental pow- 
ers. We meet with closely analogous facts with insects, for in 
ants the cerebral ganglia are of extraordinary dimensions, and in 
all the Hymenoptera these ganglia are many times larger than in 
the less intelligent orders, such as beetles,'^® On the other hand, 
no one supposes that the intelle'ct of any two animals or of any two 
men can be accurately gauged by the cubic contents of their skulls. 
It is certain that there may be extraordinary mental activity 
with an extremely small absolute mass of nervous matter: thus 
the wonderfully diversified instincts, mental powers, and affec- 
tions of ants are notorious, yet their cerebral ganglia are not so 
large as the quarter of a small pin's head. Under this point of 
view, the brain of an ant is one of the most marvelous atoms of 
matter in the world, perhaps more so than the brain of a man. 

The belief that there exists in man some close relation between 
the size of the brain and the development of the intellectual facul- 
ties is supported by the comparison of the skulls of savage and civ- 
ilized races, of ancient and modern people, and by the analogy of 
the whole vertebrate series. Dr. J. Barnard Davis has proved,^** 
by many careful measurements, that the mean internal capacity 
of the skull in Europeans is 92.3 cubic inches; in Americans 87.5; 

" 'Die Grenzen der Thierwelt, eine Betrachtung zu Darwin's Lehre,' 
1868, s. 51. 

■^ Dujardin, 'Annalesi des Sc. Nat.,' 3rd series Zoolog-. torn. xiv. 1850, 
p. 203. See also Mr. Lowne, 'Anatomy and Phys. of the Musca vomi- 
toria,' 1870, p. 14. My son, Mr. F. Darwin, dissected for me the cerebral 
ganglia of the Formica rufa. 

'» 'Philosophical Transactions,' 1869, p. 513. 



MANNER OF DEVELOPMENT. 53 

in Asiatics 87.1; and in Australians only 81.9 cubic inches. Pro- 
fessor Broca*° found that the nineteenth century skulls from graves 
in Paris were larger than those from vaults of the twelfth century, 
in the proportion of 1484 to 1426; and that the increased size, as 
ascertained by measurements, was exclusively in the frontal part 
of the skull— the seat of the intellectual faculties. Prichard is 
persuaded that the present inhabitants of Britain have "much 
more capacious brain-cases" than the ancient inhabitants. Never- 
theless, it must be admitted that some skulls of very high an- 
tiquity, such as the famous one of Neanderthal, are well developed 
and capacious.*' With respect to the lower animals, M. E. Lartet,^- 
by comparing the crania of tertiary and recent mammals belong- 
ing to the same groups, has come to the remarkable conclusion 
that the brain is generally larger and the convolutions are more 
complex in the more recent forms. On the other hand, I have 
shown®^ that the brains of domestic rabbits are considerably reduc- 
ed in bulk, in comparison with those of the wild rabbit or hare; 
and this may be attributed to their having been closely confined 
during many generations, so that they have exerted their intel- 
lect, instincts, senses and voluntary movements but little. 

The gradually increasing weight of the brain and skull in man 
must have influenced the development of the supporting spinal 
column, more especially whilst he was becoming erect. As this 
change of position was being brought about, the internal pressure 
of the brain will also have influenced the form of the skull; for 
many facts show how easily the skull is thus affected. Ethnolo- 
gists believe that it is modified by the kind of cradle in which in- 
fants sleep. Habitual spasms of the muscles, and a cicatrix from 
a severe burn, have permanently modified the facial bones, in 
young persons whose heads have become fixed either sideways or 
backwards, owing to disease, one of the two eyes has changed its 
position, and the shape of the skull has been altered apparently by 

80 'Les Selections,' M. P. Broca, 'Revue d'Anthropologies,' 1873; see 
also, as quoted in C. Vogt's 'Lectures on Man,' Eng. translat. 1864, pp. 
88, 90. Prichard, 'Phys. Hist, of Mankind, vol. i. 1838, p. 305. 

81 In the interesting- article just referred to. Prof. Broca has well 
remarked, that in civilized nations, the average capacity of the skull 
must be lowered by the preservation of a considerable number of 
individuals, weak in mind and body, who would have been promptly 
eliminated in the savage state. On the other hand, with savages, the 
average includes only the more capable individuals, who have been 
able to survive under extremely hard conditions of life. Broca thus 
explains the otherwise inexplicable fact, that the mean capacity of the 
skull of the ancient Troglodytes of Lozere is greater than that of mod- 
ern Frenchmen. 

82 'Comptes-rendus des Sciences,' &c., June 1, 1868. 

83 'The Variation of Animals and Plants under Domestication,' vol. 
i. pp. 124-129. 

6 



54 THE DESCENT OF MAN. 

the pressure of the brain in a new direction.** I have shown that 
with long-eared rabbits even so trifling a cause as the lopping for- 
ward of one ear drags forward almost every bone of the skull on 
that side; so that the bones on the opposite side no longer strictly 
correspond. Lastly, if any animal were to increase or diminisii 
much in general size, without any change in its mental powers, or 
if the mental powers were to be much increased or diminished, 
without any great change in the size of the body, the shape of the 
skull would almost certainly be altered. I infer this from my ob- 
servations on domestic rabbits, some kinds of which have become 
very much larger than the wild animal, whilst others have re- 
tained nearly the same size, but in both cases the brain has been 
much reduced relatively to the size of the body. Now I was at first 
much surprised on finding that in all these rabbits the skull had 
become elongated or dolichocephalic; for instance, of two skulls 
of nearly equal breadth, the one from a wild rabbit and the other 
from a large domestic kind, the former was 3.15 and the latter 
4.3 inches in length.*-^ One of the most marked distinctions in dif- 
ferent races of men is that the skull in some is elongated, and in 
others rounded; and here the explanation suggested by the case of 
the rabbits may hold good; for Welcker finds that short "men in- 
*'cline more to brachj'^cephaly, and tall men to dolichocephaly;"^'' 
and tall men may be compared with the larger and longer-bodied 
rabbits, all of which have elongated skulls, or are dolichocephalic. 

From these several facts we can understand, to a certain extent, 
the means by which the great size and more or less rounded form 
of the skull have been acquired by man; and these are characters 
eminently distinctive of him in comparison with the lower ani- 
mals. 

Another most conspicuous difference between man and the lower 
animals is the nakedness of his skin. Whales and porpoises 
(Cetacea),dugongs (Sirenia) and the hippopotamus are naked; and 
this may be advantageous to them for gliding through the water; 
nor would it be injurious to them from the loss of warmth, as 
the species, which inhabit the colder regions, are protected by a 
thick layer of blubber, serving the same purpose as the fur of seals 

84 Schaaffhausen ^ves from Blumenbach and Busch, the cases of the 
spasms and cicatrix, in 'Anthropolog-. Review,' Oct., 1868, p. 420. Dr. 
Jarrold ('Anthropologia,' 1808, pp. 115, 116) adduces from Camper and 
from his own observations, cases of the modification of the skull from 
the head being fixed in an unnatural position. He believes that in cer- 
tain trades, such as that of a shoemaker, where the head is habitually 
held forward, the forehead becomes more rounded and prominent. 

85 'Variation of Animals,' «S:c., vol. i. p. 117, on the elongation of the 
skull; p. 119, on the effect of the lopping of one ear. 

» Quoted by Schaaffhausen, in 'Anthropolog. Review,' Oct., 1868, 



MANNER OF DEVELOPMENT. 55 

and otters. Elephants and rhinoceroses are almost hairless; and 
as certain extinct species, which formerly lived under an Arctic 
climate, were covered with long wool or hair, it would almost ap- 
pear as if the existing species of both genera had lost their 
hairy covering from exposure to heat. This appears the more 
probable, as the elephants in India which live on elevated and 
cool districts are more hairy^' than those on the lowlands. May 
we then infer that man became divested of hair from having abor- 
iginally inhabited some tropical land? That the hair is chiefly 
retained in the male sex on the chest and face, and in both sexes 
at the junction of all four limbs with the trunk, favors this in- 
ference — on the assumption that the hair was lost before man be- 
came erect; for the parts which now retain most hair would then 
have been most protected from the heat of the sun. The crown 
of the head, however, offers a curious exception, for at all times 
it must have been one of the most exposed parts, yet it is thickly 
clothed with hair. The fact, however, that the other members of 
the order of Primates, to which man belongs, although inhabiting 
various hot regions, are well clothed with hair, generally thickest 
on the upper surface,^^ is opposed to the supposition that man be- 
came naked through the action of the sun. Mr. Belt believes*^ that 
within the tropics it is an advantage to man to be destitute of hair, 
as he is thus enabled to free himself of the multitude of ticks 
(acari) and other parasites, with which he is often infested, and 
which sometimes cause ulceration. But whether this evil is of 
suflBcient magnitude to have led to the denudation of his body 
through natural selection, may be doubted, since none of the many 
quadrupeds inhabiting the tropics have, as far as I know, ac- 
quired any specialized means of relief. The view which seems to 
me the most probable it- that man, or rather primarily woman, 
became divested of hair for ornamental purposes, as we shall see 
under Sexual Selection; and, according to this belief, it is not sur- 
prising that man should differ so greatly in hairiness from all 

^ Owen, 'Anatomy of Vertebrates,' vol. iii. p. 619. 

88 Isidore Geoffrey St.-Hilaire remarks ('Hist. Nat. Generale,' tcm. 
ii. 1859, pp. 215-217) on the head of man being covered with long hair; 
also on the upper vSurfaces of monkeys and of other mammals being 
more thickly clothed than the lower surfaces. This has likewise been 
observed by various authors. Prof. P. Gervais ('Hist. Nat. des Mam- 
miferes,' torn. i. 1854, p. 28), however, states that in the Gorilla the hair 
is thinner on the back, where it is partly rubbed off, than on the 
lower surface. 

89 The 'Naturalist in Nicaragua,' 1874, p. 209. As some confirmation of 
Mr. Belt's view, I may quote the following passage from Sir W. Deni- 
son ('Varieties of Vice-Regal Life' vol. i. 1870, p. 440): "It is said to be 
"a practice with the Australians, when the vermin get troublesome, 
"to singe themselves." 



56 THE DESCENT OF MAN. 

Other Primates, for characters, gained through sexual selection, 
often differ to an extraordinary degree in closely-related forms. 

According to a popular impression, the absence of a tail is 
eminently distinctive of man; but as those apes which come near- 
est to him are destitute of this organ, its disappearance does not 
relate exclusively to man. The tail often differs remarkably in 
length within the same genus: thus in some species of Macacus it 
fs longer than the whole body, and is formed of twenty-four verte- 
bra; in others it consists of a scarcely visible stump, containing 
«nly three or four vertebrae. In some kinds of baboons there are 
twenty-five, whilst in the mandrill there are ten very small 
stunted caudal vertebrae or, according to Cuvier,^" sometimes only 
five. The tail, whether it be long or short, almost always tapers 
towards the end; and this, I presume, results from the atrophy of 
the terminal muscles, together with their arteries and nerves, 
through disuse, leading to the atrophy of the terminal bones. But 
no explanation can at present be given of the great diversity which 
often occurs in its length. Here, however, we are more specially 
concerned with the complete external disappearance of the tail. 
Professor Broca has recently shown^^ that the tail in all quadru- 
peds consists of two portions, generally separated abruptly from 
each other; the basal portion consists of vertebrae, more or less 
perfectly channelled and furnished with apophyses like ordinary 
vertebrae; whereas those of the terminal portion are not chan- 
nelled, are almost smooth, and scarcely resemble true vertebrae. 
A tail, though not externally visible, is really present in man and 
the anthropomorphous apes, and is constructed on exactly the 
same pattern in both. In the terminal portion the vertebrae, con- 
stituting the OS coccyx, are quite rudimentary, being much reduced 
in size and number. In the basal portion, the vertebra are like- 
wise few, are united firmly together, and are arrested in develop- 
ment; but they have been rendered much broader and flatter than 
the corresponding vertebrae in the tails of other animals: they 
constitute what Broca calls the accessory sacral vertebrae. 
These are of functional importance by supporting certain internal 
parts and in other ways; and their modification is directly con- 
nected with the erect or semi-erect attitude of man and the anthro- 
pomorphous apes. This conclusion is the more trustworthy, as 
Broca formerly held a different view, which he has now abandoned. 
The modification, therefore, of the basal caudal vertebrae in man 
and the higher apes may have been effected, directly or indirectly, 
through natural selection. 

»o Mr. St. George Mivart, 'Proc. Zoolog. Soc, 1865, pp. 562, 583. Dr. J. E. 
Gray, 'Cat. Brit. Mus. : Skeletons.' Owen, 'Anatomy of Vertebrates,' 
vol. ii. p. 517. Isidore Geoff roy, 'Hist. Nat. Gen.' torn. ii. p. 244. 

»i 'Revue d'Anthropologle,' 1872; 'La Constitution des Vertebres cau- 
dales.' 



MANNER OF DEVELOPMENT. 57 

But what are we to say about the rudimentary and variable 
vertebrae of the terminal portion of the tail, forming the os 
coccyx? A notion which has often been, and will no doubt again 
be ridiculed, namely, that friction has had something to do with 
the disappearance of the external portion of the tail, is not so 
ridiculous as it at first appears. Dr. Anderson°- states that the 
extremely short tail of Macacus brunneus is formed of eleven ver- 
tebrae, including the imbedded basal ones. The extremity is ten- 
donous and contains no vertebrae; this is succeeded by five rudi- 
mentary ones, so minute that together they are only one line and 
a half in length, and these are permanently bent to one side in the 
shape of a hook. The free part of the tail, only a little above an 
inch in length, includes only four more small vertebrae. This 
short tail is carried erect; but about a quarter of its total length is 
doubled on to itself to the left; and this terminal part, which in- 
cludes the hook-like portion, serves "to fill up the interspace be- 
"tween the upper divergent portion of the callosities;" so that the 
animal sits on it, and thus renders it rough and callous. Dr. An- 
derson thus sums up his observations: "These facts seem to me 
"to have only one explanation; this tail, from its short size, is in 
"the monkey's way v/hen it sits down, and frequently becomes 
"placed under the animal while it is in this attitude; and from the 
"circumstance that it does not extend beyond the extremity of the 
"ischial tuberosities it seems as if the tail originally had been bent 
"round, by the will of the animal, into the interspace between the 
"callosities, to escape being pressed between them and the ground, 
"and that in time the curvature became permanent, fitting in of 
"itself when the organ happens to be sat upon." Under these cir- 
cumstances it is not surprising that the surface of the tail should 
have been roughened and rendered callous; and Dr. Murie,''^ who 
carefully observed this species in the Zoological Gardens, as well 
as three other closely allied forms with slightly longer tails, says 
that when the animal sits down, the tail "is necessarily thrust to 
"one side of the buttocks; and whether long or short its root is 
"consequently liable to be rubbed or chafed." As we now have 
evidence that mutilations occasionally produce an inherited ef- 
fect,^^ it is not very improbable that in short-tailed monkeys, the 
projecting part of the tail, being functionally useless, should after 

s2 'Proc. Zoolog. Soc.,' 1872, p. 210. 

«3 'Proc. Zoolog. Soc.,' 1872, p. 786. 

^ I allude to Dr. Brown-Sequard's observations on the transmitted ef- 
fect of an operation causing epilepsy in guinea-pigs, and likewise more 
recently on the analogous effects of cutting the sympathetic nerve in 
the neck. I shall hereafter have occasion to refer to Mr. Salvin's inter- 
esting case of the apparently inherited effects of mot-mots biting off the 
barbs of their own tail-feathers. See also on the general subject 'Vari- 
8.tion of Animals and Plants under Domestication,' vol. ii. pp. 22-24. 



58 THE DESCENT OF MAN. 

man.y generations have become rudimentary and distorted, from 
being continually rubbed and chafed. We see the projecting part 
in this condition in the Macacus brunneus, and absolutely aborted 
in the M. ecaudatus an4 in several of the higher apes. Finally, 
then, as far as we can judge, the tail has disappeared in man and 
the anthropomorphous apes, owing to the terminal portion having 
been injured by friction during a long lapse of time; the basal 
and embedded portion having been reduced and modified, so as to 
become suitable to the erect or semi-erect position. 
'* I have now endeavored to show that some of the most dis- 
tinctive characters of man have in all probability been acquired, 
either directly, or more commonly indirectly, through natural se- 
lection. We should bear in mind that modifications in structure 
or constitution, which do not serve to adapt an organism to its 
habits of life, to the food which it consumes, or passively to the 
surrounding conditions, cannot have been thus acquired. We 
must not, however, be too confident in deciding what modifications 
are of service to each being: v/e should remember how little we 
know about the use of many parts, or what changes in the blood 
or tissues may serve to fit an organism for a new climate or new 
kinds of food. Nor must we forget the principle of correlation, 
by which, as Isidore Geoffrey has shown in the case of man, many 
strange deviations of structure are tied together. Independently 
of correlation, a change in one part often leads, through the in- 
creased or decreased use of other parts, to other changes of a 
quite unexpected nature. It is also well to reflect on such facts, as 
the wonderful growth of galls on plants caused by the poison of 
an insect, and on the remarkable changes of color in the plum- 
age of parrots when fed on certain fishes, or inoculated with the 
poison of toads ;^^ for we can thus see that the fluids of the system, 
if altered for some special purpose, might induce other changes. 
We should especially bear in mind that modifications acquired 
and continually used during past ages for some useful purpose, 
would probably become firmly fixed, and might be long inherited. 

Thus a large yet undefined extension may safely be given to the 
direct and indirect results of natural selection; but I now admit, 
after reading the essay by Nageli on plants, and the remarks by 
various authors with respect to animals, more especially those re- 
cently made by Professor Broca, that in the earlier editions of my 
'Origin of Species' I perhaps attributed too much to the action of 
natural selection or the survival of the fittest. I have altered the 
fifth edition of the 'Origin' so as to confine my remarks to adaptive 
changes of structure; but I am convinced, from the light gained 
during even the last few years, that very many structures which 

»5 'The Variation of Animals and Plants under Domestication,' vol. ii. 
pp. 280, 282. 



MANNiCR OF DEVELOPMENT. 59 

now appear to us useless, will hereafter be proved to be use- 
ful, and will therefore come within the range of natural selection. 
Nevertheless, I did not formerly consider sufficiently the existence 
of structures, which, as far as we can at present judge, are neither 
beneficial nor injurious; and this I believe to be one of the greatest 
oversights as yet detected in my work. I may be permitted to say, 
as some excuse, that I had two distinct objects in view; firstly, to 
show that species had not been separately created, and secondly, 
that natural selection had been the chief agent of change, though 
largely aided by the inherited effects of habit, and slightly by the 
direct action of the surrounding conditions. I was not, however, 
able to annul the influence of my former belief, then almost uni- 
versal, that each species had been purposely created; and this led 
to my tacit assumption that every detail of structure, excepting 
rudiments, was of some special, though unrecognized, service. 
Any one with this assumption in his mind would naturally ex- 
tend too far the action of natural selection, either during past or 
present times. Some of those who admit the principle of evolu- 
tion, but reject natural selection, seem to forget, when criticizing 
my book, that I had the above two objects in view; hence if I have 
erred in giving to natural selection great power, which I am very 
far from admitting, or in having exaggerated its power, which is 
in itself probable, I have at least, as I hope, done good service in 
aiding to overthrow the dogma of separate creations. 

It is, as I can now see, probable that all organic beings, includ- 
ing man, possess peculiarities of structure, which neither are now, 
nor were formerly of any service to them, and which, therefore, 
are of no physiological importance. We know not what produces 
the numberless slight differences between the individuals of each 
species, for reversion only carries the problem a few steps back- 
wards; but each peculiarity must have had its efficient cause. If 
these causes, whatever they may be, were to act more uniformly 
and energetically during a lengthened period (and against this no 
reason can be assigned), the result would probably be not a mere 
slight individual difference, but a well-marked and constant modi- 
fication, though one of no physiological importance. Changed 
structures, which are in no way beneficial, cannot be kept uniform 
through natural selection, though the injurious will be thus elimi- 
nated. Uniformity of character would, however, naturally follow 
from the assumed uniformity of the exciting causes, and likewise 
from the free intercrossing of many individuals. During succes- 
sive periods, the same organism might in this manner acquire 
successive modifications, which would be transmitted in a nearly 
uniform state as long as the exciting causes remained the same 
and there was free intercrossing. Vvlth respect to the exciting 
causes we can only say, as when speaking of so-called spontaneous 
variations, that they relate much more closely to the constitution 



60 THE DESCENT OF MAN. 

of the varying organism, than to the nature of the conditions to 
which it has been subjected. 

Conclusion. — In this chapter we have seen that as man at the 
present day is liable, like every other animal, to multiform in- 
dividual differences or slight variations, so no doubt were the 
early progenitors of man; the variations being formerly induced 
by the same general causes, and governed by the same general and 
complex laws as at present. As all animals tend to multiply be- 
yond their means of subsistence, so it must have been with the 
progenitors of man; and this would inevitably lead to a struggle 
for existence and to natural selection. The latter process would 
be greatly aided by the inherited effects of the increased use of 
parts, and these two processes would incessantly react on each 
other. It appears, also, as we shall hereafter see, that various 
unimportant characters have been acquired by man through sex- 
ual selection. An unexplained residuum of change must be left to 
the assumed uniform action of those unknown agencies, which 
occasionally induce strongly marked and abrupt deviations of 
structure in our domestic productions. 

Judging from the habits of savages and of the greater number 
of the Quadrumana, primeval men, and even their ape-like pro- 
genitors, probably lived in society. With strictly social animals, 
natural selection sometimes acts on the individual, through the 
preservation of variations which are beneficial to the community. 
A community which includes a large number of well-endowed in- 
dividuals increases in number, and is victorious over other less 
favored ones; even although each separate member gains no ad- 
vantage over the others of the same community. Associated in- 
sects have thus acquired many remarkable structures, which are 
of little or no service to the individual, such as the pollen-collect- 
ing apparatus, or the sting of the worker-bee, or the great jaws of 
soldier-ants. With the higher social animals, I am not aware that 
any structure has been modified solely for the good of the com- 
munity, though some are of secondary service to it. For instance, 
the horns of ruminants and the great canine teeth of baboons ap- 
pear to have been acquired by the males as weapons for sexual 
strife, but they are used in defense of the herd or troop. In regard 
to certain mental powers the case, as we shall see in the fifth 
chapter, is wholly different; for these faculties have been chiefly, 
or even exclusively, gained for the benefit of the community, and 
the individuals thereof, have at the same time gained an ad- 
vantage indirectly. 

It has often been objected to such views as the foregoing, that 
man is one of the most helpless and defenseless creatures in the 
world; and that during his early and less well-developed con- 
dition he would have been still more helpless. The Duke of 



MANNER OF DEVELOPMENT. 61 

Argyll, for instance, insists^' that "the human frame has diverged 
"from the structure of brutes, in the direction of greater physical 
"helplessness and weakness. That is to say, it is a divergence 
"which of all others it is most impossible to ascribe to mere 
"natural selection." He adduces the naked and unprotected state 
of the body, the absence of great teeth or claws for defense, the 
small strength and speed of man, and his slight power of discover- 
ing food or of avoiding danger by smell. To these deficiencies 
there might be added one still more serious, namely, that he can- 
not climb quickly, and so escape from enemies. The loss of hair 
would not have been a great injury to the inhabitants of a warm 
country. For we know that the unclothed Fuegians can exist un- 
der a wretched climate. When we compare the defenseless state 
of man with that of apes, we must remember that the great canine 
teeth with which the latter are provided, are possessed in their full 
development by the males alone, and are chiefly used by them for 
fighting with their rivals; yet the females, which are not thus pro- 
vided, manage to survive. 

In regard to bodily size or strength, we do not know whether 
man is descended from some small species, like the chimpanzee, 
or from one as powerful as the gorilla; and, therefore, we cannot 
say whether man has become larger and stronger, or smaller and 
weaker, than his ancestors. We should, however, bear in mind 
that an animal possessing great size, strength, and ferocity and 
which, like the gorilla, could defend itself from all enemies, would 
not perhaps have become social; and this would most effectually 
have checked the acquirement of the higher mental qualities, such 
as sympathy and the love of his fellows. Hence it might have 
been an immense advantage to man to have sprung from some 
comparatively weak creature. 

The small strength and speed of man, his want of natural weap- 
ons, &c., are more than counterbalanced, firstly, by his intel- 
lectual powers, through which he has formed for himself weap- 
ons, tools, &c., though still remaining in a barbarous state, and, 
secondly, by his social qualities which lead him to give and re- 
ceive aid from his fellow-men. No country in the world abounds 
in a greater degree with dangerous beasts than Southern Africa; 
no country presents more fearful physical hardships than the Arc- 
tic regions; yet one of the puniest of races, that of the Bushmen, 
maintains itself in Southern Africa, as do the dwarfed Esquimaux 
in the Arctic regions. The ancestors of man were, no doubt, in- 
ferior in intellect, and probably in social disposition, to the lowest 
existing savages; but it is quite conceivable that they might have 
existed, or even flourished, if they had advanced in intellect, 

»« 'Primeval Man,' 1869, p. 66. 



62 THE DESCENT OF MAN. 

v.hilst gradually losing their brute-like powers, such as that of 
climbing trees, &c. But these ancestors would not have been ex- 
posed to any special danger, even if far more helpless and defense- 
less than any existing savages, had they inhabited some warm con- 
tinent or large island, such as Australia, New Guinea, or Borneo, 
which is now the home of the orang. And natural selection aris- 
ing from the competition of tribe with tribe, in some such large 
area as one of these, together with the inherited effects of habit, 
would, under favorable conditions have suflaced to raise man to 
his present high position in the organic scale. 



MENTAL POWERS. 63 



CHAPTER III. 

COMPARISON OF THE MENTAL POWERS OF MAN AND 
THE LOWER ANIMALS. 

The difference in mental power between the highest ape and the lowest 
savage, immense — Certain instincts in common — The emotions- 
Curiosity— Imitation— Attention — Memory — Imagination— P.eason— 
Progressive improvement— Tools and weapons used by animals— Ab- 
straction, self-consciousness— Language— Sense of beauty— Belief in 
God, spiritual agencies, superstitions. 

We have seen in the last two chapters that man bears in his 
bodily structure clear traces of his descent from some lower 
form; but it may be urged that, as man differs so greatly in 
his mental power from all other animals, there must be some 
error in this conclusion. No doubt the difference in this respect 
is enormous, even if we compare the mind of one of the lowest 
savages, who has no words to express any number higher than 
four, and who uses hardly any abstract terms for common objects 
or for the affections,^ with that of the most highly organized ape. 
The difference would, no doubt, still remain immense, even if one 
of the higher apes had been improved or civilized as much as 
a dog has been in comparison with its parent-form, the wolf or 
jackal. The Puegians rank amongst the lowest barbarians, but 
I was continually struck with surprise how closely the three 
natives on board H.M.S. "Beagle," who had lived some years in 
England and could talk a little English, resembled us in disposi- 
tion and in most of our mental faculties. If no organic being ex- 
cepting man had possessed any mental power, or if his powers had 
been of a wholly different nature from those of the lov/er animals, 
then we should never have been able to convince ourselves that 
our high faculties had been gradually developed. But it can be 
shown that there is no fundamental difference of this kind. We 
must also admit that there is a much wider interval in mental 
power between one of the lowest fishes, as a lamprey or lancelet, 

^ See the evidence on those points as given by Lubbock, 'Prehistoric 
V'imes,' p. 354, &a 



64 THE DESCENT OF MAN. 

and one of the higher apes, than between an ape and man; yet 
this interval is filled up by numberless gradations. 

Nor is the difference slight in moral disposition between a 
barbarian, such as the man described by the old navigator Byron, 
who dashed his child on the rocks for dropping a basket of sea- 
urchins, and a Howard or Clarkson; and in intellect between a 
savage who uses hardly any abstract terms, and a Newton or 
Shakspeare. Differences of this kind between the highest men 
of the highest races and the lowest savages, are connected by the 
finest gradations. Therefore it is possible that they might pass 
and be developed into each other. 

My object in this chapter is to, show that there is no funda- 
mental difference between man and the higher mammals in their 
mental faculties. Each division of the subject might have been 
extended into a separate essay, but must here be treated briefly. 
As no classification of the mental powers has been universally 
accepted, I shall arrange my remarks in the order most con- 
venient for my purpose; and will select those facts which have 
struck me most, with the hope that they may produce some 
effect on the reader. 

With respect to animals very low in the scale, I shall give 
some additional facts under Sexual Selection, showing that their 
mental powers are much higher than might have been expected. 
The variability of the faculties in the individuals of the same 
species is an important point for us, and some few illustrations 
will here be given. But it would be superfluous to enter into 
many details on this head, for I have found on frequent inquiry, 
that it is the unanimous opinion of all those who have long 
attended to animals of many kinds, including birds, that the in- 
dividuals differ greatly in every mental characteristic. In what 
manner the mental powers were first developed in the lowest 
organisms, is as hopeless an inquiry as how life itself first 
originated. These are problems for the distant future, if they are 
ever to be solved by man. 

As man possesses the same senses as the lower animals, his 
fundamental intuitions must be the same. Man has also some 
few instincts in common, as that of self-preservation, sexual love, 
the love of the mother for her new-born offspring, the desire 
possessed by the latter to suck, and so forth. But man, perhaps, 
has somewhat fewer instincts than those possessed by the ani- 
mals which come next to him in the series. The orang in the 
Eastern islands, and the chimpanzee in Africa, build platforms 
on which they sleep; and, as both species follow the same habit, 
it might be argued that this was due to instinct, but we cannot 
feel sure that it is not the result of both animals having similar 
wants, and possessing similar powers of reasoning. These apes, 
as we may assume, avoid the many poisonous fruits of the tropics, 



MENTAL POWERS. 65' 

and man has no such knowledge: hut as our domestic animals, 
v/hen taken to foreign lands, and when first turned out in the 
spring, often eat poisonous herbs, which they afterwards avoid, 
we cannot feel sure that the apes do not learn from their own 
experience or from that of their parents what fruits to select. 
It is, however, certain, as we shall presently see, that apes have 
an instinctive dread of serpents, and probably of other dangerous 
animals. 

The fewness and the comparative simplicity of the instincts in 
the higher animals are remarkable in contrast with those of the 
lower animals. Cuvier maintained that instinct and intelligence 
stand in an inverse ratio to each other; and some have thought 
that the intellectual faculties of the higher animals have been 
gradually developed from their instincts. But Pouchet, in an 
interesting essay,- has shown that no such inverse ratio really 
exists. Those insects which possess the most wonderful instincts 
are certainly the most intelligent. In the vertebrate series, the 
least intelligent members, namely fishes and amphibians, do not 
possess complex instincts; and amongst mammals the animal 
most remarkable for its instincts, namely the beaver, is highly 
intelligent, as will be admitted by every one who has read Mr. 
Morgan's excellent work.^ 

Although the first dawnings of intelligence, according to Mr. 
Herbert Spencer,^ have been developed through the multiplica- 
tion and co-ordination of reflex actions, and although many of 
the simpler instincts graduate into reflex actions, and can hardly 
be distinguished from them, as in the case of young animals 
sucking, yet the more complex instincts seem to have originated 
independently of intelligence. I am, however, very far from 
wishing to deny that instinctive actions may lose their flxe^i and 
untaught character, and be replaced by others performed by the 
aid of the free will. On the other hand, some intelligent actions, 
after being performed during several generations, become con- 
verted into instincts and are inherited, as when birds on oceanic 
islands learn to avoid man. These actions may then be said 
to be degraded in character, for they are no longer performed 
through reason or from experience. But the greater number of 
the more complex instincts appear to have been gained in a 
wholly different manner, through the natural selection of varia- 
tions of simpler instinctive actions. Such variations appear to 
arise from the same unknown causes acting on the cerebral 
organization, which induce slight variations or individual dif- 

2 'L'lnstinct chez les Insectes.' 'Revue des Deux Mondes,' Feb. 1870, 
p. 690. 
•^ 'The American Beaver and his Works/ 1868. 
* 'The Principles of Psychology,' 2nd edit. 1870, pp. 418-443. 
6 



66 THE DESCENT OP MAN. 

ferences in other parts of the body; and these variations, owing 
to our ignorance, are often said to arise spontaneously. We can, 
I think, come to no other conclusion with respect to the origin of 
the more complex instincts, when v/e reflect on the marvelous 
instincts of sterile worker-ants and bees, which leave no off- 
spring to inherit the effects of experience and of modified habits. 

Although, as we learn from the above-mentioned insects and 
the beaver, a high degree of intelligence is certainly compatible 
with complex instincts, and although actions, at first learned 
voluntarily can soon through habit be performed with the quick- 
ness and certainty of a reflex action, yet it is not improbable that 
there is a certain amount of interference between the devel- 
opment of free intelligence and of instinct, — which latter implies 
some inherited modification of the brain. Little is known about 
the functions of the brain, but we can perceive that as the intel- 
lectual powers become highly developed, the various parts of the 
brain must be connected by very intricate channels of the freest 
intercommunication; and as a consequence, each separate part 
would perhaps tend to be less well fitted to answer to particular 
sensations or associations in a definite and inherited — that is 
instinctive — manner. There seems even to exist some relation 
between a low degree of intelligence and a strong tendency to the 
formation of fixed, though not inherited habits; for as a sagacious 
physician remarked to me, persons who are slightly imbecile tend 
to act in everything by routine or habit; and they are rendered 
much happier if this is encouraged. 

I have thought this digression worth giving, because we may 
easily underrate the mental powers of the higher animals, and 
especially of man, when we compare their actions founded on the 
memory of past events, on foresight, reason, and imagination, 
with exactly similar actions instinctively performed by the lower 
animals; in this latter case the capacity of performing such 
actions has been gained, step by step, through the variability of 
the mental organs and natural selection, without any conscious 
intelligence on the part of the animal during each successive 
generation. No doubt, as Mr. Wallace has argued,^ much of the 
intelligent work done by man is due to imitation and not to 
reason; but there is this great difference between his actions 
and many of those performed by the lower animals, namely, that 
man cannot, on his first trial, mak(3, for instance, a stone hatchet 
or a canoe, through his power of imitation. He has to learn his 
work by practice; a beaver, on the other hand, can make its 
dam or canal, and a bird its nest, as well, or nearly as well, and 

5 'Contributions to the Theory of Natural Selection,' 1870, p. 212. 



MENTAL POWERS. 67 

a spider its wonderful web, quite as well,® the first time it tries, 
as when old and experienced. 

To return to our immediate subject: the lower animals, like 
man, manifestly feel pleasure and pain, happiness and misery. 
Happiness is never better exhibited than by young animals, such 
as puppies, kittens, lambs, &c., when playing together, like our 
own children. Even insects play together, as has been described 
by that excellent observer, P. Huber,'^ who saw ants chasing and 
pretending to bite each other, like so many puppies. 

The fact that the lower animals are excited by the same 
emotions as ourselves is so well established, that it will not be 
necessary to weary the reader by many details. Terror acts in 
the same manner on them as on us, causing the muscles to 
tremble, the heart to palpitate, the sphincters to be relaxed, and 
the hair to stand on end. Suspicion, the offspring of fear, is 
eminently characteristic of most wild animals. It is, I think, 
impossible to read the account given by Sir E. Tennent, of the 
behavior of the female elephants, used as decoys, without ad- 
mitting that they intentionally practice deceit, and well know 
what they are about. Courage and timidity are extremely variable 
qualities in the individuals of the same species, as is plainly seen 
in our dogs. Some dogs and horses are ill-tempered, and easily 
turn sulky; others are good-tempered; and these qualities are f^'^^^^ 
certainly inherited. Every one knows how liable animals are 
to furious rage, and how plainly they show it. Many, and prob- 
ably true, anecdotes have been published on the long-delayed and 
artful revenge of various animals. The accurate Rengger, and 
Brehm^ state that the American and African monkeys which 
they kept tame, certainly revenged themselves. Sir Andrew 
Smith, a zoologist whose scrupulous accuracy was known to many 
persons, told me the following story of which he was himself an 
eye-witness; at the Cape of Good Hope an officer had often 
plagued a certain baboon, and the animal, seeing him approaching 
one Sunday for parade, poured water into a hole and hastily 
made some thick mud, which he skillfully dashed over the officer 
as he passed by, to the amusement of many bystanders. For 
long afterwards the baboon rejoiced and triumphed whenever he 
saw his victim. 

The love of a dog for his master is notorious; as an old 

6 For the evidence on this head, see Mr. J. Traherne Moggridge's 
most interesting work, 'Harvesting Ants and Trap-door Spiders,' 1873, 
pp. 126, 128. 

■^ 'Recherches sur les Moeurs des Fourmis,' 1810, p. 173. 

8 All the following statements, given on the authority of these two 
naturalists, are taken from Rengger's 'Naturgesch. der Saugethiere 
von Paraguay,' 1830, s. 41-57, and from Brehtn's 'Thierieben,' B. i. s. 



g3 THE DESCENT OF MAN. 

writer quaintly says,^ "A dog is the only thing on this earth 
"that luvs you more than he luvs himself." 

In the agony of death a dog has been known to caress his 
master, and every one has heard of the dog suffering under vivi- 
section, who licked the hand of the operator; this man, unless the 
operation was fully justified by an increase of our knowledge, 
or unless he had a heart of stone, must have felt remorse to the 
last hour of his life. 

As WhewelP" has well asked, "who that reads the touching 
"instances of maternal affection, related so often of the women of 
"all nations, and of the females of all animals, can doubt that the 
"principle of action is the same in the two cases?" We see mater- 
nal affection exhibited in the most trilling details; thus Rengger 
observed an American monkey (a Cebus) carefully driving away 
the flies which plagued her infant; and Duvaucel saw a Hylobates 
washing the faces of her young ones in a stream. So intense is 
the grief of female monkeys for the loss of their young, that 
it invariably caused the death of certain kinds kept under confine- 
ment by Brehm in N. Africa. Orphan monkeys were always 
adopted and carefully guarded by the other monlj:eys, both males 
and females. One female baboon had so capacious a heart that 
she not only adopted young monkeys of other species, but stole 
young dogs and cats, which she continually carried about. Her 
kindness, however, did not go so far as to share her food with 
her adopted offspring, at which Brehm was surprised, as his 
monkeys always divided everything quite fairly with their own 
young ones. An adopted kitten scratched this affectionate baboon, 
who certainly had a fine intellect, for she was much astonished at 
being scratched, and immediately examined the kitten's feet, and 
without more ado bit off the claws." In the Zoological Gardens, 
I heard from the keeper that an old baboon (C. chacma) had 
adopted a Rhesus monkey; but when a young drill and mandrill 
were placed in the cage, she seemed to perceive that these 
monkeys, though distinct species, were her nearer relatives, for 
she at once rejected the Rhesus and adopted both of them. The 
young Rhesus, as I saw, was greatly discontented at being thus 
rejected, and it would, like a naughty child, annoy and attack the 
young drill and mandrill whenever it could do so with safety; this 
conduct exciting great indignation in the old baboon. Monkeys 

» Quoted by Dr. Lauder Lindsay, in his 'Physiology of Mind in the 
Lower Animals;' 'Journal of Mental Science,' April, 1871, p. 38. 

10 'Bridgewater Treatise,' p. 263. 

" A critic, without any grounds ('Quarterly Ileview>* July, 1871, p. 
72), disputes the possibility of this act as described by Brehm, for the 
sake of discrediting my work. Therefore I tried, and found that I 
could readily seize with my own teeth the sharp little claws of a 
kitten nearly five weeks old. 



MENTAL POWERS. 69 

will also, according to Brehm, defend their master when attacked 
by any one, as well as dogs to whom they are attached, from the 
attacks of other dogs. But we here trench on the subjects of sym- 
pathy and fidelity, to which I shall recur. Some of Brehm's 
monkeys took much delight in teasing a certain old dog whom 
they disliked, as well as other animals, in various ingenious ways. 

Most of the more complex emotions are common to the 
higher animals and ourselves. Every one has seen how jealous 
a dog is of his master's affection, if lavished on any other crea- 
ture; and I have observed the same fact with monkeys. This 
shows that animals not only love, but have desire to be loved. 
Animals manifestly feel emulation. They love approbation or 
praise; and a dog carrying a basket for his master exhibits in 
a high degree self-complacency or pride. There can, I think, be 
no doubt that a dog feels shame, as distinct from fear, and some- 
thing very like modesty when begging too often for food. A 
great dog scorns the snarling of a little dog, and this may 
be called magnanimity. Several observers have stated that 
monkeys certainly dislike being laughed at; and they sometimes 
invent imaginary offenses. In the Zoological Gardens I saw a 
baboon who always got into a furious rage when his keeper took 
out a letter or book and read it aloud to him; and his rage was 
so violent that, as I witnessed on one occasion, he bit his own leg 
till the blood flowed. Dogs show what may be fairly called a 
sense of humor, as distinct from mere play; if a bit of stick or 
other such object be thrown to one, he will often carry it away 
for a short distance; and then squatting down with it on the 
ground close before him, will wait until his master comes quite 
close to take it away. The dog will then seize it and rush away in 
triumph, repeating the same manoeuvre, and evidently enjoying 
the practical joke. 

We will now turn to the more intellectual emotions and fac- 
ulties, which are very important, as forming the basis for the de- 
velopment of the higher mental powers. Animals manifestly 
enjoy excitement, and suffer from ennui, as may be seen with 
dogs, and, according to Rengger, with monkeys. All animals 
feel Wonder, and many exhibit Curiosity. They sometimes suffer 
from this latter quality, as when the hunter plays antics and thus 
attracts them; I witnessed this with deer, and so it is with the 
wary chamois, and with some kinds of wild-ducks. Brehm gives 
a curious account of the instinctive dread, which his monkeys 
exhibited, for snakes; but their curiosity was so great that they 
could not desist from occasionally satiating their horror in a 
most human fashion, by lifting up the lid of the box in which the 
snakes were kept. I was so much surprised at his account, that 
I took a stuffed and coiled-up snake into the monkey-house at the 
Zoological Gardens, and the excitement thus caused was one of 

6 



7d THE DESCENT OF MAN. 

the most curious spectacles v/^hich I ever beheld. Three species 
of Cercopithecus were the most alarmed; they dashed about their 
cages, and uttered sharp signal cries of danger, which were under- 
stood by the other monkeys. A few young monkeys and one old 
Anubis baboon alone took no notice of the snake. I then placed 
the stuffed specimen on the ground in one of the larger com- 
partments. After a time all the monkeys collected round it in 
a large circle, and staring intently, presented a most ludicrous ap- 
pearance. They became extremely nervous; so that when a 
wooden ball, with which they were familiar as a plaything, was 
accidentally moved in the straw, under which it was partly 
hidden, they all instantly started away. These monkeys behaved 
very differently when a dead fish, a mouse,^ a living turtle, and 
other new objects were placed in their cages; for though at first 
frightened, they soon approached, handled and examined them. I 
then placed a live snake in a paper bag, with the mouth loosely 
closed, in one of the larger compartments. One of the monkeys im- 
mediately approached, cautiously opened the bag a little, peeped 
in, and instantly dashed away. Then I witnessed what Brehm has 
described, for monkey after monkey, with head raised high and 
turned on one side, could not resist taking a momentary peep 
into the upright bag, at the dreadful object lying quietly at the 
bottom. It would almost appear as if monkeys had some notion 
of zoological afiinities, for those kept by Brehm exhibited a 
strange, though mistaken, instinctive dread of innocent lizards 
and frogs. An orang, also, has been known to be much alarmed 
at the first sight of a turtle. ^^ 

? The principle of Imitation is strong in man, and especially, as 
I have myself observed, with savages. In certain morbid states 
"of the brain this tendency is exaggerated to an extraordinary 
degree; some hemiplegic patients and others, at the commence- 
ment of inflammatory softening of the brain, unconsciously 
imitate every word which is uttered, whether in their own or in 
a foreign language, and every gesture or action which is per- 
formed near them." Desor^^ has remarked that no animal volun- 
tarily imitates an action performed by man, until in the ascending 
scale we come to monkeys, which are well known to be ridiculous 
mockers. Animals, however, sometimes imitate each other's 
actions: thus two species of wolves, which had been reared by 
dogs, learned to bark, as does sometimes the jackal," but whether 

^ I have given a short account of their behavior on this occasion in 
my 'Expression of the Emotions,' p. 43. 

13 W. C. L. Martin. 'Nat. Hist, of Mammalia,' 1841, p. 405. 

1* Dr. Bateman 'On Apasia,' 1870, p. 110. 

15 Quoted by Vogt, 'Memoire sur les Microcephales,' 1867, p. 168. 

18 'Tke Variation of Animals and Plants imdie'r Domfesticatioo,' vol. i, 
p. 27. 



MENTAL POWERS. 71 

this can be called voluntary imitation is another question. Birds 
imitate the songs of their parents, and sometimes of other birds; 
and parrots are notorious imitators of any sound which they often 
hear. Bureau de la Malle gives an account^' of a dog reared by a 
cat, who learned to imitate the well-known action of a cat licking 
her paws, and thus washing her ears and face; this was also 
witnessed by the celebrated naturalist Audouin. I have received 
several confirmatory accounts; in one of these, a dog had not been 
suckled by a cat, but had been brought up with one, together 
with kittens, and had thus acquired the above habit, which he 
ever afterwards practiced during his life of thirteen years. Bureau 
de la Malle's dog likewise learned from the kittens to play with a 
ball by rolling it about with his fore paws, and springing on it. 
A correspondent assures me that a cat in his house used to put 
her paws into jugs of milk having too narrow a mouth for her 
head. A kitten of this cat soon learned the same trick, and prac- 
ticed it ever afterwards, whenever there was an opportunity. 

The parents of many animals, trusting to the principle of 
imitation in their young, and more especially to their instincdve 
or inherited tendencies, may be said to educate them. We see 
this when a cat brings a live mouse to her kittens; and Bureau 
de la Malle has given a curious account (in the paper above 
quoted) of his observations on hawks which taught their young 
dexterity, as well as judgment of distances, by first dropping 
through the air dead mice and sparrows, which the young gen- 
erally failed to catch, and then bringing them live birds and 
letting them loose. 

Hardly any faculty is more important for the intellectual 
progress of man than Attention. Animals clearly manifest this 
power, as when a cat watches by a hole and prepares to spring 
on its prey. Wild animals sometimes become so absorbed when 
thus engaged, that they may be easily approached. Mr. Bartlett 
has given me a curious proof how variable this faculty is in 
monkeys. A man who trains monkeys to act in plays, used to 
purchase common kinds from the Zoological Society at the price 
of five pounds for each; but he offered to give double the price, 
if he might keep three or four of them for a few days, in order 
to select one. When asked how he could possibly learn so soon, 
whether a particular monkey would turn out a good actor, he 
answered that it all depended on their power of attention. If, 
when he was talking and explaining anything to a monkey, its 
attention was easily distracted, as by a fly on the wall or other 
trifling object, the case was hopeless. If he tried by punishment 
to make an inattentive monkey act, it turned sulky. On the 



I'' 'Annales des Sc. Nat.' (Ist Series), torn. xaai. p. 39-7. 



72 THE DESCENT OF MAN. 

other hand, a monkey which carefully attended to him could 
always be trained. 

It is almost superfluous to state that animals have excellent 
Memories for persons and places. A baboon at the Cape of Good 
Hope, as I have been informed by Sir Andrew Smith, recognized 
him with joy after an absence of nine months. I had a dog who 
was savage and averse to all strangers, and I purposely tried his 
memory after an absence of five years and two days. I went 
near the stable where he lived, and shouted to him in my old 
manner; he showed no joy, but instantly followed me out walk- 
ing, and obeyed me, exactly as if I had parted with him only 
half an hour before. A train of old associations, dormant during 
five years, had thus been instantaneously awakened in his mind. 
Even ants, as P. Huber^* has clearly shown, recognized their 
fellow-ants belonging to the same community after a separation 
of four months. Animals can certainly by some means judge of 
the intervals of time between recurrent events. 
(_. The Imagination is one of the highest prerogatives of man. 
By this faculty he unites former images and ideas, independently 
of the will, and thus creates brilliant and novel results. A poet, 
as Jean Paul Richter remarks,^^ "who must reflect whether he 
"shall make a character say yes or no — to the devil with him; 
"he is only a stupid corpse." Dreaming gives us the best notion 
of this power; as Jean Paul again says, "The dream is an in- 
"voluntary art of poetry." The value of the products of our 
imagination depends of course on the number, accuracy, and 
clearness of our impressions, on our judgment and taste in select- 
ing or rejecting the involuntary combinations, and to a certain 
extent on our power of voluntarily combining them. As dogs, 
cats, horses, and probably all the higher animals, even birds-" 
have vivid dreams, and this is shown by their movements and 
the sounds uttered, we must admit that they possess some power 
of imagination. There must be something special, which causes 
dogs to howl in the night, and especially during moonlight, in 
that remarkable and melancholy manner called baying. All dogs 
do not do so; and, according to Houzeau,-^ they do not then 
look at the moon, but at some fixed point near the horizon. 
Houzeau thinks that their imaginations are disturbed by the 
vague outlines of the surrounding objects, and conjure up before 

18 'Les Mceurs des Fourmis,' 1810, p. 150. 

1^ Quoted in Dr. Maudsley's Physiology and Pathology of Mind,' 1868, 
pp. 19, 220. 

20 Dr. Jerdon, 'Birds of India,' vol. i. 1862, p. xxi. Houzeau says that 
his parokeets and canary-birds dreamt: 'Facultes Mental es,' torn. ii. 
p. 136. 

21 'Facultes Mentales des Anknaux,' 1872, torn. ii. p. 181. 



MENTAL POWERS. 73 

them fantastic images: if this be so, their feelings may almost 
be called superstitious. 

Of all the faculties of the human mind, it will, I presume, be 
admitted that Reason stands at the summit. Only a few persons 
now dispute that animals possess some power of reasoning. 
Animals may constantly be seen to pause, deliberate, and resolve. 
It is a significant fact, that the more the habits of any particular 
animal are studied by a naturalist, the more he attributes to 
reason and the less to unlearned instincts.-- In future chapters 
we shall see that some animals extremely low in the scale appar- 
ently display a certain amount of reason. No doubt it is often 
difficult to distinguish between the power of reason and that of 
instinct. For instance. Dr. Hayes, in his work on 'The Open 
Polar Sea,' repeatedly remarks that his dogs, instead of continu- 
ing to draw the sledges in a compact body, diverged and separ- 
ated when they came to thin ice, so that their weight might be 
more evenly distributed. This was often the first warning 
which the travelers received that the ice was becoming thin and 
dangerous. Now, did the dogs act thus from the experience of 
each individual, or from the example of the older and wiser dogs, 
or from an inherited habit, that is from instinct? This instinct, 
may possibly have arisen since the time, long ago, when dogs 
were first employed by the natives in drawing their sledges; or 
the Arctic wolves, the parent-stock of the Esquimaux dog, may 
have acquired an instinct, impelling them not to attack their 
prey in a close pack, when on thin ice. 

We can only judge by the circumstances under which actions 
are performed, whether they are due to instinct, or to reason, or 
to the mere association of ideas: this latter principle, however, 
is intimately connected with reason. A curious case has been 
given by Prof. Mobius,-^ of a pike, separated by a plate of glass 
from an adjoining aquarium stocked with fish, and who often 
dashed himself with such violence against the glass in trying to 
catch the other fishes, that he was sometimes completely 
stunned. The pike went on thus for three months, but at last 
learned caution, and ceased to do so. The plate of glass was then 
removed, but the pike would not attack these particular fishes, 
though he would devour others which were afterward intro- 
duced; so strongly was the idea of a violent shock associated 
in his feeble mind with the attempt on his former neighbors. 
If a savage, who had never seen a large plate-glass window, 
were to dash himself even once against it, he would for a long 

22 Mr. Li. H. Morgan's work on 'The American Beaver,' 1868, offers 
a good illustration of this remark. I cannot help thinking, however, 
that he goes too far in underrating the power of instinct. 

-^ 'Die Bewegungen der Thiere,' &c., 1873, p. 11. 



74 THE DESCENT OF MAN. 

time afterwards associate a shock with a window-frame; but 
very differently from the pike, he would probably reflect on the 
nature of the impediment, and be cautious under analogous cir- 
cumstances. Now with monkeys, as we shall presently see, a 
painful or merely a disagreeable impression, from an action once 
performed, is sometimes sufficient to prevent the animal from 
repeating it. If we attribute this difference between the monkey 
and the pike solely to the association of ideas being so much 
stronger and more persistent in the one than the other, though 
the pike often received much the more severe injury, can we 
maintain in the case of man that a similar difference implies the 
possession of a fundamentally different mind? 

Houzeau relates-* that, whilst crossing a wide and arid plain 
in Texas, his two dogs suffered greatly from thirst, and that 
between thirty and forty times they rushed down the hollows 
to search for water. These hollows were not valleys, and there 
were no trees in them, or any other difference in the vegetation, 
and as they were absolutely dry there could have been no 
smell of damp earth. The dogs behaved as if they knew that 
a dip in the ground offered them the best chance of finding 
water, and Houzeau has often witnessed the same behavior in 
other animals. 

I have seen, as I daresay have others, that when a small 
object is thrown on the ground beyond the reach of one of the 
elephants in the Zoological Gardens, he blows through his trunk 
on the ground beyond the object, so that the current reflected 
on all sides may drive the object within his reach. Again a well- 
known ethnologist, Mr. Westropp, informs me that he observed in 
Vienna a bear deliberately making with his paw a current in some 
water, which was close to the bars of his cage, so as to draw 
a piece of floating bread within his reach. These actions of the 
elephant and bear can hardly be attributed to instinct or inherited 
habit, as they would be of little use to an animal in a state of 
nature. Now, what is the difference between such actions, when 
performed by an uncultivated man, and by one of the higher 
animals? 

The savage and the dog have often found water at a low level, 
and the coincidence under such circumstances has become asso- 
ciated in their minds. A cultivated man would perhaps make 
some general proposition on the subject; but from all that we 
know of savages it is extremely doubtful whether they would do 
so, and a dog certainly would not. But a savage, as well as a 
dog, would search in the same way, though frequently dis- 
appointed; and in both it seems to be equally an act of reason, 
whether or not any general proposition on the subject is con- 

2* 'Facultes Mental es des Animaux,' 1872, torn. ii. p. 265. 



MENTAL POWERS. 75 

sciously placed before the mind.-'' The same would apply to 
the elephant and the bear making currents in the air or water. 
Tlie savage would certainly neither know nor care by what law, 
the desired movements were effected; yet his act would be 
guided by a rude process of reasoning, as surely as would a 
philosopher in his longest chain of deductions. There would no 
doubt be this difference between him and one of the higher 
animals', that he would take notice of much slighter circum- 
stances and conditions, and would observe any connection be- 
tween them after much less experience, and this would be of 
paramount importance. I kept a daily record of the actions of 
one of my infants, and when he was about eleven months old, 
and before he could speak a single word, I was continually 
struck with the greater quickness, with which all sorts of objects 
and sounds were associated together in his mind, compared with 
that of the most intelligent dogs I ever knew. But the higher 
animals differ in exactly the same way in this power of associa- 
tion from those low in the scale, such as the pike, as well as in 
that of drawing inferences and of observation. 

The promptings of reason, after very short experience, are well 
shown by the following actions of American monkeys, which 
stand low in their order. Rengger, a most careful observer, 
states that when he first gave eggs to his monkeys in Paraguay, 
they smashed them, and thus lost much of their contents; after- 
wards they gently hit one end against some hard body, and 
picked off the bits of shell with their fingers. After cutting 
themselves only once with any sharp tool they would not touch 
it again, or would handle it with the greatest caution. Lumps 
of sugar were often given them wrapped up in paper; and 
Rengger sometimes put a live wasp in the paper, so that in 
hastily unfolding it they got stung; after this had once hap- 
pened, they always first held the packet to their ears to detect 
any movement within.-*^ 

The following cases relate to dogs. Mr. Colquhoun-' winged 
two wild-ducks, which fell on the further side of a stream; his 
retriever tried to bring over both at once, but could not succeed; 

25 Prof. Huxley has analyzed with admirable clearness the mental 
steps by which a man, as well as a dog-, arrives at a conclusion in a 
case analogous to that given in my text. See his article, 'Mr. Darwin's 
Critics,' in the 'Contemporary Review,' Nov. 1871, p. 462, and in his 
'Critiques and Essays,' 1873, p. 279. 

^ Mr. Belt, in his most interesting work, 'The Naturalist in Nicara^ 
gua,' 1874 (p. 119), likewise describes various actions of a tamed Cebus, 
which, I think, clearly show that this animal possessed some reasoning 
power. 

-' 'The Moor and the Loch,' p. 45. Col. Hutchinson on 'Dog Break- 
ing,' 1850, p. 46. 



76 THE DESCENT OF MAN. 

she then, though never before known to ruffle a feather, 
deliberately killed one, brought over the other, and returned 
for the dead bird. Col. Hutchinson relates that two partridges 
were shot at once, one being killed, the other wounded; the 
latter ran away, and was caught by the retriever, who on her 
return came across the dead bird; "she stopped, evidently 
"greatly puzzled, and after one or two trials, finding she could 
"nqt take it up without permitting the escape of the winged 
"bird, she considered a moment, then deliberately murdered it 
"by giving it a severe crunch, and afterwards brought away 
"both together. This was the only known instance of her 
"ever having willfully injured any game." Here we have reason 
though not quite perfect, for the retriever might have brought 
the wounded bird first and then returned for the dead one, as in 
the case of the two wild-ducks. I give the above cases, as resting 
on the evidence of two independent witnesses, and because in both 
instances the retrievers, after deliberation, broke through a habit 
which is inherited by them (that of not killing the game re- 
trieved), and because they show how strong their reasoning fac- 
ulty must have been to overcome a fixed habit. 

I will conclude by quoting a remark by the illustrious Hum- 
boldt.-^ "The muleteers in S. America say, *I will not give 
" 'you the mule whose step is easiest, but la mas racional, — the 
" 'one that reasons best;' " and as he adds, "this popular expres- 
"sion, dictated by long experience, combats the system of ani- 
"mated machines, better perhaps than all the arguments of specu- 
"lative philosophy." Nevertheless some writers even yet deny 
that the higher animals possess a trace of reason; and they en- 
deavor to explain away, by what appears to be mere verbiage,^ 
all such facts as those above given. 

It has, I think, now been shown that man and the higher ani- 
mals, especially the Primates, have some few instincts in common. 
All have the same senses, intuitions, and sensations, — similar 
passions, affections, and emotions, even the more complex ones, 
such as jealousy, suspicion, emulation, gratitude, and magnanim- 

28 'Personal Narrative,' Eng-. translat. vol. iii. p. 106. 

^ I am glad to find that so acute a reasoner as Mr. Leslie Stephen 
('Darwinism and Divinity, Essays on Free- thinking,' 1873, p. SO), in 
speaking of the supposed impassable harrier between the minds of man 
and the lower animals, says, "The distinctions, indeed, which have 
"been drawn, seem to us to rest upon no better foundation than a 
"great many other metaphysical distinctions; that is the assumption 
"that because you can give two things different names, they must 
"therefore have different natures. It is difficult to understand how 
"anybody who has ever kept a dog, or seen an elephant, can have any 
"doubts as to an animal's power of performing the essential processes 
*'of reasoning." 



MENTAL POWERS. 77 

ity; they practice deceit and are revengeful; they are sometimes 
susceptible to ridicule, and even have a sense of humor; they 
teel wonder and curiosity; they possess the same faculties of 
imitation, attention, deliberation, choice, memory, imagination, 
the association of ideas, and reason, though in very different de- 
grees. The individuals of the same species graduate in intellect 
from absolute imbecility to high excellence. They are also 
liable to insanity, though far less often than in the case of man.^" 
Nevertheless, many authors have insisted that man is divided by 
an insuperable barrier from all the lov/er animals in his mental 
faculties. I formerly made a collection of above a score of such 
aphorisms, but they are almost worthless, as their wide difference 
and number prove the difficulty, if not the impossibility, of the 
attempt. It has been asserted that man alone is capable of 
progressive improvement; that he alone makes use of tools or 
fire, domesticates other animals, or possesses property; that no 
animal has the power of abstraction, or of forming general con- 
cepts, is self-conscious and comprehends itself; that no animal 
employs language; that man alone has a sense of beauty, is liable 
to caprice, has the feeling of gratitude, mystery, &c.; believes in 
God, or is endowed with a conscience. I will hazard a few re- 
marks on the more important and interesting of these points. 

Archbishop Sumner formerly maintained^^ that man alone is 
capable of progressive improvement. That he is capable of in- 
comparably greater and more rapid improvement than is any 
other animal, admits of no dispute; and this is mainly due to 
his power of speaking and handing down his acquired knowledge. 
With animals, looking first to the individual, every one who has 
had any experience in setting traps, knows that young animals 
can be caught much more easily than old ones; and they 
can be much more easily approached by an enemy. Even 
with respect to old animals, it is impossible to catch many 
in the same place and in the same kind of trap, or to 
destroy them by the same kind of poison; yet it is im- 
probable that all should have partaken of the poison, and 
impossible that all should have been caught in a trap. They 
must learn caution by seeing their brethren caught or poi- 
soned. In North America, where the fur-bearing animals have 
long been pursued, they exhibit according to the unanimous 
testimony of all observers, an almost incredible amount of 
sagacity, caution and cunning; but trapping has been there so 
long carried on, that inheritance may possibly have come into 
play. I have received several accounts that when telegraphs are 

^° See 'Madness in Animals,' by Dr. W. Lauder Lindsay, in 'Journal 
of Mental Science,' July 1871. 
31 Quoted by Sir C. Lyell, 'Antiquity of Man,' p. 497. 



78 THE DESCENT OF MAN. 

first set up in any district, many birds kill themselves by flying 
against the v/ires, but that in the course of a very few years they 
learn to avoid this danger, by seeing, as it would appear, their 
comrades killed."- 

If we look to successive generations, or to the race, there is no 
doubt that birds and other animals gradually both acquire and 
lose caution in relation to man or other enemies ;^^ and this 
caution is certainly in chief part an inherited habit or instinct, 
but in part the result of individual experience. A good observer, 
Leroy,^* states, that in districts where foxes are much hunted, 
the young, on first leaving their burrows, are incontestably much 
more wary than the old ones in districts where they are not much 
disturbed. 

Our domestic dogs are descended from wolves and jackals,-^ 
and though they may not have gained in cunning, and may have 
lost in wariness and suspicion, yet they have progressed in 
certain moral qualities, such as in affection, trust-worthiness, 
temper, and probably in general intelligence. The common rat has 
conquered and beaten several other species throughout Europe, 
in parts of North America, New Zealand, and recently in Formosa, 
as well as on the mainland of China. Mr. Swinhoe,^" who de- 
scribes these two latter cases, attributes the victory of the com- 
mon rat over the large Mus cominga to its superior cunning; and 
this latter quality may probably be attributed to the habitual 
exercise of all its faculties in avoiding extirpation by man, as 
well as to nearly all the less cunning or weak-minded rats having 
been continuously destroyed by him. It is, however, possible that 
the success of the common rat may be due to its having pos- 
sessed greater cunning than its fellow-species, before it became 
associated with man. To maintain, independently of any direct 
evidence, that no animal during the course of ages has progressed 
in intellect or other mental faculties, is to beg the question of 
the evolution of species. We have seen that, according to Lartet, 
existing mammals belonging to several orders have larger brains 
than their ancient tertiary prototypes. 

It has often been said that no animal uses any tool; but 
the chimpanzee in a state of nature cracks a native fruit, some- 

32 For additional evidence, with details, see M. Houzeau, 'Les Facultes 
Mentales,' torn. ii. 1872, p. 147. 

S3 See, with respect to birds on oceanic islands, my 'Journal of Re- 
searches during the voyage of the "Beagle" ' 1845, p. 398. 'Origin of 
Species,' 5th edit. p. 260. 

34 'Lettres Phil, sur I'lntelligence des Animaux,' nouvelle edit. 1892, 
p. 86. 

33 See the evidence on this head in chap. i. vol. i. 'On the Variation 
of Animals and Plants under Domestication.' 

38 'Proc. Zoolog. Soc' 1864, p. 186. 



MENTAL POWERS. 79 

what like a walnut, with a stone.^^ Rengger^* easily taught an 
American monkey thus to break open hard palm-nuts; and after- 
wards of its own accord, it used stones to open other kinds of 
nuts, as well as boxes. It thus also removed the soft rind of fruit 
that had a disagreeable flavor. Another monkey was taught to 
open the lid of a large box with a stick, and afterwards it used 
the stick as a lever to move heavy bodies; and I have myself seen 
a young orang put a stick into a crevice, slip his hand to the other 
end, and use it in the proper manner as a lever. The tamed ele- 
phants in India are well known to break off branches of trees 
and use them to drive away the flies; and this same act has been 
observed in an elephant in a state of nature.^^" I have seen a young 
orang, when she thought she was going to be whipped, cover and 
protect herself with a blanket or straw. In these several cases 
stones and sticks were employed as implements; but they are 
likewise used as weapons. Brehm^ states, on the authority of the 
well-known traveler Schimper, that in Abyssinia when the 
baboons belonging to one species (C. gelada) descend in troops 
from the mountains to plunder the fields, they sometimes en- 
counter troops of another species (C. hamadryas), and then a 
fight ensues. The Geladas roll down great stones, which the Ham- 
adryas try to avoid, and then both species, making a great up- 
roar, rush furiously against each other. Brehm, when, accom- 
panying the Duke of Coburg-Gotha, aided in an attack with fire- 
arms on a troop of baboons in the pass of Mensa in Abyssinia. 
The baboons in return rolled so many stones down the mountain, 
some as large as a man's head, that the attackers had to beat a 
hasty retreat; and the pass was actually closed for a time against 
the caravan. It deserves notice that these baboons thus acted 
in concert. Mr. Wallace*^ on three occasions saw female orangs, 
accompanied by their young, "breaking off branches and the 
"great spiny fruit of the Durian tree, with every appearance of 
"rage; causing such a shower of missiles as effectually kept us 
"from approaching too near the tree." As I have repeatedly seen, 
a chimpanzee will throw any object at hand at a person who 
offends him; and the before mentioned baboon at the Cape of 
Good Hope prepared mud for the purpose. 

In the Zoological Gardens, a monkey, which had weak teeth, 
used to break open nuts with a stone; and I was assured by the 
keepers that after using the stone, he hid it in the straw, and 

37 Savag-e and Wyman in 'Boston Journal of Nat. Hist.' vol. iv. 1843- 
44, p. 383. 
28 'Saug-ethiere von Paraguay,' 1830, s. 51-56. 
s9 The 'Indian Field,' March 4, 1871. 
« 'Thierleben,' B. i. s. 79, 82. 
*i 'The Malay Archipelag-o,* vol. i. 1869, p. 87. 



go THE DESCENT OF MAN. 

would not let any other monkey touch it. Here, then, we have 
the idea of property; but this idea is common to every dog with 
a bone, and to most or all birds with their nests. 

The Duke of Argyll'^ remarks, that the fashioning of an imple- 
ment for a special purpose is absolutely peculiar to man; and he 
considers that this forms an immeasurable gulf between him and 
the brutes. This is no doubt a very important distinction; but 
there appears to me much truth in Sir J. Lubbock's suggestion,"^ 
that when primeval man first used flint-stones for any purpose, 
he would have accidentally splintered them, and would then have 
used the sharp fragments. From this step it would be a small 
one to break the flints on purpose, and not a very wide step to 
fashion them rudely. This latter advance, however, may have 
taken long ages, if we may judge by the immense interval of 
time which elapsed before the men of the neolithic period took to 
grinding and polishing their stone tools. In breaking the flints, 
as Sir J. Lubbock likewise remarks, sparks would have been 
emitted, and in grinding them heat would have been evolved: 
thus the two usual methods of "obtaining fire may have orig- 
"inated." The nature of fire would have been known in the 
many volcanic regions where lava occasionally flows through for- 
ests. The anthropomorphous apes, guided probably by instinct, 
build for themselves temporary platforms; but as many instincts 
are largely controlled by reason, the simpler ones, such as this 
of building a platform, might readily pass into a voluntary and 
conscious act. The orang is known to cover itself at night with 
the leaves of the Pandanus; and Brehm states that one of his 
baboons used to protect itself from the heat of the sun by throw- 
ing a straw-mat over its head. In these several habits, we prob- 
ably see the first steps towards some of the simpler arts, such 
as rude architecture and dress, as they arose amongst the early 
progenitors of man. 

Abstraction^ Oeneral Co7iceptions, Self -consciousness, Mental 
Individuality. — It would be very difiicult for any one with even 
much more knowledge than I possess, to determine how far ani- 
mals exhibit any traces of these high mental powers. This diffi- 
culty arises from the impossibility of judging what passes through 
the mind of an animal; and again, the fact that writers differ to 
a great extent in the meaning which they attribute to the above 
terms, causes a further difficulty. If one may judge from various 
articles which have been published lately, the greatest stress 
seems to be laid on the supposed entire absence in animals of the 
power of abstraction, or of forming general concepts. But when 



*2 'Primeval Man,' 1869, pp. 145, 147. 
*s 'Prehistoric Times,' 1865, p. 473, &c. 



MENTAL POWERS. 81 

a dog sees another dog at a distance, it is often clear that he per- 
ceives that it is a dog in the abstract; for when he gets nearer his 
whole manner suddenly changes, if the other dog be a friend. 
A recent writer remarks, that in all such cases it is a pure as- 
sumption to assert that the mental act is not essentially of the 
same nature in the animal as in man. If either refers what he 
perceives with his senses to a mental concept, then so do both.** 
When I say to my terrier, in an eager voice (and I have made the 
trial many times), "Hi, hi, where is it?" she at once takes it as 
a sign that something is to be hunted, and generally first looks 
quickly all around, and then rushes into the nearest thicket, to 
scent for any game, but finding nothing, she looks up into any 
neighboring tree for a squirrel. Now do not these actions clearly 
show that she had in her mind a general idea or concept that some 
animal is to be discovered and hunted? 

It may be freely admitted that no animal is self-conscious, if 
by this term it is implied, that he refiects on such points, as 
whence he comes or whither he will go, or v/hat is life and death, 
and so forth. But how can we feel sure that an old dog with an 
excellent memory and some power of imagination, as shown by 
his dreams, never reflects on his past pleasures or pains in the 
chase? And this would be a form of self-consciousness. On the 
other hand, as Biichner*^ has remarked, how little can the hard- 
worked wife of a degraded Australian savage, who uses very 
few abstract words, and cannot count above four, exert her self- 
consciousness, or reflect on the nature of her own existence. It 
is generally admitted, that the higher animals possess memory, 
attention, association, and even some imagination and reason. 
If these powers, which differ much in different animals, are 
capable of improvement, there seems no great improbability in 
more complex faculties, such as the higher forms of abstraction, 
and self-consciousness, &c., having been evolved through the 
development and combination of the simpler ones. It has been 
urged a_gainst the views here maintained, that it is impossible 
to say at what point in the ascending scale animals become 
capable of abstraction, &c.; but who can say at what age this 
occurs in our young children? We see at least that such powers 
are developed in children by imperceptible degrees. 

That animals retain their mental individuality is unquestion- 
able. When my voice awakened a train of old associations in 
the mind of the before-mentioned dog, he must have retained 
his mental Individuality, although every atom of his brain had 

^ Mr. Hookham, in a letter to Prof. Max Muller, in the 'Birmingham 
News,' May, 1873. 

*^ 'Conferences sur la Theorie Darwinienne,' French translat. 1869, 
p. 132. 



a2 THE DESCENT OF MAN. 

probably undergone change more than once during the interval 
of five years. This dog might have brought forward the argu- 
ment lately advanced to crush all evolutionists, and said, "I abide 

"amid all mental moods and all material changes The teaching 

"that atoms leave their impressions as legacies to other atoms 
"falling into the places they have vacated is contradictory of the 
"utterance of consciousness, and is therefore false; but it is the 
"teaching necessitated by evolutionism, consequently the hypothe- 
"sis is a false one."*" 

Language. — This faculty has justly been considered as one of 
the chief distinctions between man and the lower animals. But 
man, as a highly competent judge. Archbishop Whately remarks, 
"is not the only animal that can make use of language to express 
"what is passing in his mind, and can understand, more or less, 
"what is so expressed by another."*^ In Paraguay the Cebus 
azarse when excited utters at least six distinct sounds, which 
excite in other monkeys similar emotions.*^ The movements of 
the features and gestures of monkeys are understood by us, and 
they partly understand ours, as Rengger and others declare. It 
is a more remarkable fact that the dog, since being domesticated, 
has learnt to bark*^ in at least four or five distinct tones. Al- 
though barking is a new art, no doubt the wild parent-species of 
the dog expressed their feelings by cries of various kinds. With 
the domesticated dog we have the bark of eagerness, as in the 
chase; that of anger, as well as growling; the yelp or hov/1 of 
despair, as when shut up; the baying at night; the bark of joy, as 
when starting on a walk with his master; and the very distinct 
one of demand or supplication, as when wishing for a door or 
window to be opened. According to Houzeau, who paid particular 
attention to the subject, the domestic fowl utters at least a dozes 
significant sounds.^" 

The habitual use of articulate language is, however, peculiai 
to man; but he uses, in common with the lower animals, inarticu- 
late cries to express his meaning, aided by gestures and the move. 
ments of the muscles of the face.'' This especially holds good 
with the more sim^ple and vivid feelings, which are but little 
connected with our higher intelligence. Our cries of pain, fear 



^ The Rev. Dr. J. McCann, 'Anti-Darwinism,' 1869, p. 13. 

^7 Quoted in 'Anthropological Review,' 1864, p. 158. 

*^ Reng-g-er, ibid. s. 45. 

*9 See my 'Variation of Animals and Plants under Domestication, 
vol. i. p. 27. 

™ 'Facultes Mentales des Animaux,' torn. ii. 1872, p. 346-349. 

"1 See a discussion on this subject in Mr. E. B. Tylor's very interest- 
ing work, 'Researches into the Early History of Mankind,' 1S65, chaps, 
ii. to iv. 



MENTAL POWERS. 83 

surprise, anger, together with their appropriate actions, and the 
murmur of a mother to her beloved child, are more expressive 
than any words. That which distinguishes man from the lower 
animals is not the understanding of articulate sounds, for, as 
every one knov»rs, dogs understand many words and sentences. 
In this respect they are at the same stage of development as 
infants, betv/een the ages of ten and twelve months, v/ho under- 
stand many words and short sentences, but cannot yet utter a 
single word. It is not the mere articulation which is our dis- 
tinguishing character, for parrots and other birds possess this 
power. Nor is it the mere capacity of connecting definite sounds 
with definite ideas; for it is certain that some parrots, which have 
been taught to speak, connect unerringly words with things, and 
persons with events.^^ The lov/er animals differ from man solely 
in his almost infinitely larger power of associating together the 
most diversified sounds and ideas; and this obviously depends on 
the high development of his mental powers. 

As Home Took, one of the founders of the noble science of 
philology, observes, language is an art, like brewing or baking; 
but writing would have been a better simile. It certainly is not 
a true instinct, for every language has to be learnt. It differs, 
however, widely from all ordinary arts, for man has an instinctive 
tendency to speak, as we see in the babble of our young children; 
whilst no child has an instinctive tendency to brew, bake, or 
write. Moreover, no philologist now supposes that any language 
has been deliberately invented; it has been slowly and uncon- 
sciously developed by many steps.^^ The sounds uttered by birds 

52 I have received several detailed accounts to this effect. Admiral 
Sir J. Sullivan, whom I know to be a careful observer, assures me that 
an African parrot, long kept in his father's house, invariably called 
certain persons of the household, as well as visitors, by their names. 
He said "good morning" to every one at breakfast, and "good night" 
to each as they left the room at night, and never reversed these salu- 
tations. To Sir J. Sullivan's father lie used to add to the "good morn- 
ing" a short sentence, which was never once repeated after his father's 
death. He scolded violently a strange dog which came into the room 
through the open window; and he scolded another parrot (saying 
"you naughty polly") which had got out of its cage, and v/as eating 
apples on the kitchen table. See also, to the same effect, Houzeau en 
parrots, 'Facultes Mentales,' torn. ii. p. 309. Dr. A. Moschkan informs 
me that he knew a starling which never made a mistake in saying in 
German "good morning" to persons arriving, and "good-bye, old fel- 
low," to those departing. I could add several other such cases. 

53 See some good remarks on this head by Prof. Whitney, in his 
•Oriental and Linguistic Studies,' 1873, p. 354. He observes that the 
desire of communication between man is the living force, which, in 
the development of language, "works both consciously ajid uncon- 



84 THE DESCENT OF MAN. 

offer in several respects th.e nearest analogy to language, for all 
the members of the same species utter the same instinctive cries 
expressive of their emotions; and all the kinds which sing, exert 
their power instinctively; but the actual song, and even the call 
notes, are learnt from their parents or foster-parents. These 
sounds, as Daines Barrington^* has proved, "are no more innate 
"than language is in man," The first attempts to sing "may be 
"compared to the imperfect endeavor in a child to babble." The 
young males continue practicing, or as the bird-catchers say, 
"recording," for ten or eleven months. Their first essays show 
hardly a rudiment of the future song; but as they grow older 
we can perceive what they are aiming at; and at last they are 
said "to sing their song round." Nestlings which have learnt the 
song of a distinct species, as with the canary-birds educated in the 
Tyrol, teach and transmit their new song to their offspring. The 
slight natural differences of song in the same species inhabiting 
different districts may be appositely compared, as Barrington 
remarks, "to provincial dialects;" and the songs are allied, though 
distinct species may be compared with the languages of distinct 
races of man. I have given the foregoing details to show that 
an instinctive tendency to acquire an art is not peculiar to man. 

With respect to the origin of articulate language, after having 
read on the one side the highly interesting works of Mr. Hens- 
leigh Wedgwood, the Rev. F. Parrar, and Prof. Schleicher,^" and 
the celebrated lectures of Prof. Max Miiller on the other side, I 
cannot doubt that language owes its origin to the imitation and 
modification of various natural sounds, the voices of other ani- 
mals, and man's own instinctive cries, aided by signs and gestures. 
When we treat of sexual selection we shall see that primeval man, 
or rather some early progenitor of man, probably first used his 
voice in producing true musical cadences, that is in singing, as 
do some of the gibbon-apes at the present day; and we may con- 
clude from a widely-spread analogy, that this power would have 
been especially exerted during the courtship of the sexes, — would 
have expressed various emotions, such as love, jealousy, triumph, 
— and would have served as a challenge to rivals. It is, therefore, 

"sciously; consciously as reg-ards the immediate end to be attained; 
"unconsciously as regards the further consequences of the act." 

54 Hon. Daines Barring-ton in 'Philosoph. Transactions,' 1773, p. 262. 
See also Dureau de la Malle, in 'Ann. des. Sc. Nat.' 3rd series, Zoolog-. 
tom. X. p. 119. 

55 'On the Origin of Language,' by H. Wedgwood, 1866. 'Chapters on 
Language,' by the Rev. P. W. Farrar, 1865. These works are most in- 
teresting. See also 'De la Phys. et de Parole' par Albert Lemoine, 1865, 
p. 190. The work on this subject, by the late Prof. Aug. Schleicher, 
has been translated by Dr. Bikkers into English, under the title of 
'Darwinism tested by the Science of Language,' 1869. 



MENTAL POWERS. 85 

probable that the imitation of musical cries by articulate sounds 
may have given rise to words expressive of various complex 
emotions. The strong tendency in our nearest allies, the monkeys, 
in microcephalous idiots,^" and in the barbarous races of mankind, 
to imitate v?-hatever they hear deserves notice, as bearing on the 
subject of imitation. Since monkeys certainly understand much 
that is said to them by man, and when wild, utter signal-cries of 
danger to their fellows;" and since fowls give distinct warnings 
for danger on the ground, or in the sky from hawks (both, as 
well as a third cry, intelligible to dogs) ,^^ may not some unusually 
wise ape-like animal have imitated the growl of a beast of prey, 
and thus told his fellow-monkeys the nature of the expected 
danger? This would have been a first step in the formation of a 
language. 

As the voice was used more and more, the vocal organs would 
have been strengthened and perfected through the principle of 
the inherited effects of use; and this would have reacted on the 
power of speech. But the relation between the continued use of 
language and the development of the brain, has no doubt been 
far more important. The mental powers in some early progenitor 
of man must have been more highly developed than in any existing 
ape, before even the most imperfect form of speech could have 
come into use; but we may confidently believe that the con- 
tinued use and advancement of this power would have reacted on 
the mind itself, by enabling and encouraging it to carry on long 
trains of thought. A complex train of thought can no more be 
carried on without the aid of words, whether spoken or silent, 
than a long calculation without the use of figures or algebra. It 
appears, also, that even an ordinary train of thought almost re- 
quires, or is greatly facilitated by some form of language, for 
the dumb, deaf, and blind girl, Laura Bridgman, was observed to 
use her fingers whilst dreaming.^^ Nevertheless, a long succession 
of vivid and connected ideas may pass through the mind without 
the aid of any form of language, as we may infer from the move- 
ments of dogs during their dreams. We have, also, seen that ani- 
mals are able to reason to a certain extent, manifestly without 
the aid of language. The intimate connection between the brain, 
as it is now developed in us, and the faculty of speech, is well 



s« Vog-t, 'Memoire sur les Microcephales,' 1867, p. 169. With respect to 
savag-es, I have given some facts in my 'Journal of Researches,' &c., 
1845, p. 206. 

^'^ See clear evidence on this head in the two v/crks so often quoted, 
by Brehm and Rengger. 

^ Houzeau gives a very curious account of his observations on this 
subject in his 'Facultes Mentales des Animaux,' tom. ii., p. 348. 

50 See remarks on this head by Dr. Maudsley, 'The Physiology and 
Pathology of Mind,' 2nd edit. 1868, p. 199. 
7 



gg THE DESCENT OF MAN. 

shown by those curious cases of brain-disease in which speech is 
specially affected, as when the power to remember substantives 
is lost, whilst other words can be correctly used, or where sub- 
stantives of a certain class, or all except the initial letters of 
substantives and proper names are forgotten.*^ There is no more 
improbability in the continued use of the mental and vocal organs 
leading to inherited changes in their structure and functions 
than in the case of handwriting, which depends partly on the 
form of the hand and partly on the disposition of the mind; and 
hand-writing is certainly inherited.®^ 

Several writers, more especially Prof. Max Miiller,*'- have lately 
insisted that the use of language implies the power of forming 
general concepts; and that as no animals are supposed to possess 
this power, an impossible barrier is formed between them and 
man.^ With respect to animals, I have already endeavored to 
show that they have this power, at least in a rude and incipient 
degree. As far as concerns infants of from ten to eleven months 
old, and deaf-mutes, it seems to me incredible, that they should 
be able to connect certain sounds with certain general ideas as 
quickly as they do, unless such ideas were already formed in 
their minds. The same remark may be extended to the more in- 
telligent animals; as Mr. Leslie Stephen observes/* "A dog 
"frames a general concept of cats or sheep, and knows the cor- 

^ Many curious cases have been recorded. See, for instance, Dr. 
Bateman 'On Aphasia,' 1870, pp. 27, 31, 53, 100, &c. Also, 'Inquiries Con- 
cerning the Intellectual Powers,' by Dr. Abercrombie, 1838, p. 150. 

«i 'The Variation of Animals and Plants under Domestication,' vol. 
ii. p. 6. 

«2 Lectures on 'Mr. Darwin's Philosophy of Lang-uag-e,' 1873. 

«8 The judgment of a distinguished philologist, such as Prof. Whitney, 
will have far more weight on this point than anything that I can say. 
He remarks ('Oriental and Linguistic Studies,' 1873, p. 297), in speaking 
of Bleek's views: "Because on the grand scale language is the neces- 
"sary auxiliary of thought, indispensable to the development of the 
"power of thinking, to the distinctness and variety and complexity of 
"cognitions to the full mastery of consciousness; therefore he would 
"fain make thought absolutely impossible without speech, identifying 
"the faculty with its instrument. He might just as reasonably assert 
"that the human hand cannot act without a tool. With such a doctrine 
"to start from, he cannot stop short of Muller's worst paradoxes, that 
"an infant (in fans, not speaking) is not a human being, and that deaf 
"mutes do not become possessed of reason until they learn to twist 
"their fingers into imitation of spoken words." Max Muller gives in 
italics ('Lectures on Mr. Darwin's Philosophy of Language,' 1873, th'rd 
lecture) the following aphorism: "There is no thought without words, 
"as little as there are words without thought." What a strange defi- 
nition must here be given to the word thought! 
« 'Essays on Free- thinking,' &c., 1873, p. 82. 



MENTAL POWERS. 87 

"responding words as well as a philcsoptier. And the capacity to 
"understand is as good a proof of vocal intelligence, though in an 
"inferior degree, as the capacity to speak." 

Why the organs now used for speech should have heen originally 
perfected for this purpose, rather than any other organs, it is 
not difficult to see. Ants have considerable powers of intercom- 
munication by means of their antennae, as shown by Huber, who 
devotes a whole chapter to their language. We might have used 
our fingers as efficient instruments, for a person with practice 
can report to a deaf man every word of a speech rapidlj'- delivered 
at a public meeting; but the loss of our hands, whilst thus em- 
ployed, would have been a serious inconvenience. As all the 
higher mammals possess vocal organs, constructed on the same 
general plan as ours, and used as a means of communication, it 
was obviously probable that these same organs would be still fur- 
ther developed if the power of communication had to be im- 
proved; and this has been effected by the aid of adjoining and 
well adapted parts, namely the tongue and lips.*^^ The fact ^of 
the higher apes not using their vocal organs for speech, no doubt 
depends on their intelligence not having been sufficiently ad- 
vanced. The possession by them of organs, which with long- 
continued practice might have been used for speech, although 
not thus used, is paralleled by the case of many birds which pos- 
sess organs fitted for singing, though they never sing. Thus, the 
nightingale and crow have vocal organs similarly constructed, 
these being used by the former for diversified song, and by the 
latter only for croaking.*^® If it be asked why apes have not had 
their intellects developed to the same degree as that of man, 
general causes only can be assigned in answer, and it is unreason- 
able to expect anything more definite, considering our ignorance 
with respect to the successive stages of development through 
which each creature has passed. 

The formation of different languages and of distinct species, 
and the proofs that both have been developed through a gradual 
process, are curiously parallel." But we can trace the formation 

«5 See some good remarks to this effect by Dr. Maudsley, 'The Phys- 
iology and Pathology of Mind,' 1868, p. 199. 

66 Macgillivray, 'Hist, of British Birds,' vol. ii. 1839, p. 29. An excel- 
lent observer, Mr. Blackwall remarks that the magpie learns to pro- 
nounce single words, and even short sentences, more readily than 
almost any other British bird; yet, as he adds, after long and closely 
investigating its habits, he has never known it in a state of nature, 
display any unusual capacity for imitation. 'Researches in Zoology,' 
1834, p. 158. 

6'^ See the very interesting parallelism between the development of 
species and languages, given by Sir C. Lyell in 'The Geolog. Evidences 
of the Antiquity of Man,' 1863, chap, xxiii. 



V^ 



88 THE DESCENT OF MAN. 

of many words further back than that of species, for we can 
perceive how they actually arose from the imitation of various 
sounds. We find in distinct languages striking homologies due 
to community of descent, and analogies due to a similar process 
of formation. The manner in which certain letters or sounds 
change when others change is very like correlated growth. We 
have in both cases the reduplication of parts, the effects of long- 
continued use, and so forth. The frequent presence of rudi- 
ments, both in language and in species, is still more remarkable. 
The letter m in the word am, means I; so that in the expression 
I am, a superfluous and useless rudiment has been retained. In 
the spelling also of words, letters often remain as the rudiments 
of ancient forms of pronunciation. Languages, like organic be- 
ings, can be classed in groups under groups; and they can be 
classed either naturally according to descent, or artificially by 
other characters. Dominant languages and dialects spread widely, 
and lead to the gradual extinction of other tongues. A language, 
like a species, when once extinct, never, as Sir C. Lyell remarks, 
reappears. The same language never has two birth-places. Dis- 
tinct languages may be crossed or blended together.^^ We see 
variability in every tongue, and new words are continually crop- 
ping up; but as there is a limit to the powers of the memory, 
single words, like whole languages, gradually become extinct. As 
Max Miiller^^ has well remarked: — "A struggle for life is con- 
"stantly going on amongst the words and grammatical forms in 
"each language. The better, the shorter, the easier forms are con- 
"stantly gaining the upper hand, and they owe their success to 
"their own inherent virtue." To these more important causes 
of the survival of certain words, mere novelty and fashion may be 
added; for there is in the mind of man a strong love for slight 
changes in all things. The survival or preservation of certain 
favored words in the struggle for existence is natural selection. 

The perfectly regular and wonderfully complex construction 
of the languages of many barbarous nations has often been ad- 
vanced as a proof, either of the divine origin of these languages, 
or of the high art and former civilization of their founders. Thus 
F. von Schlegel writes: "In those languages which appear to 
"be at the lowest grade of intellectual culture, we frequently 
"observe a very high and elaborate degree of art in their gram- 
"matical structure. This is especially the case with the Basque 
"and the Lapponian, and many of the American languages."^" But 

«8 See remarks to this effect by the Rev. F. W. Farrar, in an inter- 
esting- article, entitled 'Philology and Darwinism' in 'Nature,' March 
24th, 1870, p. 528. 

«» 'Nature,' Jan. 6th, 1870, p. 257. 

™ Quoted by C. S. Wake, 'Chapters on Man,' 1868, p. lOL 



MENTAL POWERS. ' 89 

it is assuredly an error to speak of any language as an art, in the 
sense of its having been elaborately and methodically formed. 
Philologists now admit that conjugations, declensions, &c., orig- 
inally existed as distinct words, since joined together; and as 
such words express the most obvious relations between objects 
and persons, it is not surprising that they should have been used 
by the men of most races during the earliest ages. With respect 
to perfection, the following illustration will best show how easily 
we may err; a Crinoid sometimes consists of no less than 150,000 
pieces of shell,^^ all arranged with perfect symmetry in radiating 
lines; but a naturalist does not consider an animal of this kind 
as more perfect than a bilateral one with comparatively few 
parts, and with none of these parts alike, excepting on the op- 
posite sides of the body. He justly considers the differentiation 
and specialization of organs as the test of perfection. So with 
languages; the most symmetrical and complex ought not to be 
ranked above irregular, abbreviated, and bastardized languages, 
which have borrowed expressive words and useful forms of con- 
struction from various conquering, conquered, or immigrant races. 
From these few and imperfect remarks I conclude that the ex- 
tremely complex and regular construction of many barbarous lan- 
guages, is no proof that they owe their origin to a special act 
of creation.'- Nor, as we have seen, does the faculty of articulate 
speech in itself offer any insuperable objection to the belief that 
man has been developed from some lower form. 

Sense of Beauty. — This sense has been declared to be peculiar 
to man. I refer here only to the pleasure given by certain colors, 
forms, and sounds, and which may fairly be called a sense of the 
beautiful; with cultivated men such sensations are, hov/ever, 
intimately associated with complex ideas and trains of thought. 
V/hen we behold a male bird elaborately displaying his graceful 
plumes or splendid colors before the female, whilst other birds, 
not thus decorated, make no such display, it is impossible to 
doubt that she admires the beauty of her male partner. As 
women everywhere deck themselves with these plumes, the beauty 
of such ornaments cannot be disputed. As we shall see later, 
the nests of humming-birds, and the playing passages of bower- 
birds are tastefully ornamented with gayly-colored objects; and 
this shows that they must receive some kind of pleasure from the 
sight of such things. Yv^ith the great majority of animals, how- 
ever, the taste for the beautiful is confined, as far as we can judge, 
to the attractions of the opposite sex. The sweet strains poured 

■^1 Buckland, 'Bridgewater Treatise,' p. 411. 

■^2 See some g-ood remarks on the simplification of languages, hy Sir J. 
Lubbock, 'Origin of Civilization,' 1870, p. 278. 



^ 



90 THE DESCENT OF MAN. 

forth by many male birds during the season of love, are certainly 
admired by the females, of which fact evidence will hereafter be 
given. If female birds had been incapable of appreciating the 
beautiful colors, the ornaments, and voices of their male partners, 
all the labor and anxiety exhibited by the latter in displaying their 
charms before the females would have been thrown away; and 
this it is impossible to admit. Why certain bright colors should 
excite pleasure cannot, I presume, be explained, any more than 
why certain flavors and scents are agreeable; but habit has 
something to do with the result, for that which is at first un- 
pleasant to our senses, ultimately becomes pleasant, and habits 
are inherited. With respect to sounds, Helmholtz has explained 
to a certain extent on physiological principles, why harmonies 
and certain cadences are agreeable. But besides this, sounds fre- 
quently recurring at irregular intervals, are highly disagreeable, 
as every one will admit who has listened at night to the irregular 
flapping of a rope on board ship. The same principle seems to 
come into play with vision, as the eye prefers symmetry or figures 
with some regular recurrence. Patterns of this kind are em- 
ployed by even the lowest savages as ornaments; and they have 
been developed through sexual selection for the adornment of 
some male animals. Whether we can or not give any reason for 
the pleasure thus derived from vision and hearing, yet man and 
many of the lower animals are alike pleased by the same colors, 
graceful shading and forms, and the same sounds. 

The taste for the beautiful, at least as far as female beauty is 
concerned, is not of a special nature in the human mind; for it 
differs widely in the different races of man, and is not quite the 
same even in the different nations of the same race. Judging 
from the hideous ornaments, and the equally hideous music ad- 
mired by most savages, it might be urged that their aesthetic 
faculty was not so highly developed as in certain animals, for 
instance, as in birds. Obviously no animal would be capable of 
admiring such scenes as the heavens at night, a beautiful land- 
scape, or refined music; but such high tastes are acquired through 
culture, and depend on complex associations; they are not en- 
joyed by barbarians or by uneducated persons. 

Many of the faculties, which have been of inestimable service 
to man for his progressive advancement, such as the powers of 
the imagination, wonder, curiosity, an undefined sense of beauty, 
a tendency to imitation, and the love of excitement or novelty, 
could hardly fail to lead to capricious changes of customs and 
fashions. I have alluded to this point, because a recent writer'^ 
has oddly fixed on Caprice "as one of the most remarkable and 
"typical differences between savages and brutes." But not only 

'3 'The Spectator,' Dec. 4th 1869, p. 1430. 



MENTAL. POWERS. 91 

can we partially understand how it is that man is from various 
conflicting influences rendered capricious, but that the lower 
animals are, as we shall hereafter see, likewise capricious in their 
affections, aversions, and sense of beauty. There is also reason 
to suspect that they love novelty, for its own sake. 

Belief in Ood — Religion. — There is no evidence that man was 
aboriginally endowed with the ennobling belief in the existence 
of an Omnipotent God. On the contrary there is ample evidence, 
derived not from hasty travelers, but from men who have long »/ 
resided with savages, that numerous races have existed, and still 
exist, who have no idea of one or more gods, and who have no 
words in their languages to express such an idea.'^* The question 
is of course wholly distinct from that higher one, whether there 
exists a Creator and Ruler of the universe; and this has been 
answered in the affirmative by some of the highest intellects that 
have ever existed. 

If, however, we include under the term "religion" the belief 
in unseen or spiritual agencies, the case is wholly different; for 
this belief seems to be universal with the less civilized races. 
Nor is it difficult to comprehend how it arose. As soon as the 
important faculties of the imagination, wonder, and curiosity, 
together with some power of reasoning, had become partially 
developed, man would naturally crave to understand what was 
passing around him, and would have vaguely speculated on his 
own existence. As Mr. M'Lennan'^^ has remarked, "Some explana- 
"tion of the phenomena of life, a man must feign for himself; 
"and to judge from the universality of it, the simplest hypothesis, 
"and the first to occur to men, seems to have been that natural 
"phenomena are ascribable to the presence in animals, plants, 
"and things, and in the forces of nature, of such spirits prompting 
"to action as men are conscious they themselves possess." It 
is also probable, as Mr. Tylor has shown, that dreams may have 
first given rise to the notion of spirits; for savages do not readily 
distinguish between subjective and objective impressions. When 
a savage dreams, the figures which appear before him are be- 
lieved to have come from a distance, and to stand over him; or 
"the soul of the dreamer goes out on its travels, and comes home 
"with a remembrance of what it has seen."^^ But until the facul- 

'* See an excellent article on this subject by the Rev. F. W. Farrar, 
in the 'Anthropological Review,' Aug-., 1864, p. ccxvii. For further 
facts see Sir J. Lubbock, 'Prehistoric Times,' 2nd edit. 1869, p. 564; and 
especially the chapters on Religion in his 'Origin of Civilization,' 1870. 

"^^ 'The Worship of Animals and Plants,' in the 'Fortnightly Review,' 
Oct. 1, 1869, p. 422. 

"s Tyior, 'Early History of Mankind,' 1865, p. 6. See also the three 
striking chapters on the Development of Religion, in Lubbock's 'Origin 



92 THE DESCENT OF MAN. 

ties of imagination, curiosity, reason, «fec., had been fairly well 
developed in the mind of man, his dreams would not have led him 
to believe in spirits, any more than in the case of a dog. 

The tendency in savages to imagine that natural objects and 
agencies are animated by spiritual or living essences, is perhaps 
illustrated by a little fact which I once noticed: my dog, a full- 
grown and very sensible animal, was lying on the lawn during a 
hot and still day; ' but at a little distance a slight breeze occasion- 
ally moved an open parasol, which would have been wholly dis- 
regarded by the dog, had any one stood near it. As it was, every 
time that the parasol slightly moved, the dog growled fiercely 
and barked. He must, I think, have reasoned to himself in a 
rapid and unconscious manner, that movement without any ap- 
parent cause indicated the presence of some strange living agent, 
and that no stranger had a right to be on his territory. 

The belief in spiritual agencies would easily pass into the 
belief in the existence of one or more gods. For savages would 
naturally attribute to spirits the same passions, the same love of 
vengeance or simplest form of justice, and the same affections 
which they themselves feel. The Fuegians appear to be in this 
respect in an intermediate condition, for when the surgeon on 
board the "Beagle" shot some young ducklings as specimens, York 
Minster declared in the most solemn manner, "Oh, Mr. Bynoe, 
"much rain, much snow, blow much;" and this was evidently a 
retributive punishment for wasting human food. So again he 
related how, when his brother killed a "wild man," storms long 
raged, much rain and snow fell. Yet we could never discover 
that the Fuegians believed in what we should call a God, or prac- 
ticed any religious rites; and Jemmy Button, with justifiable 
pride, stoutly maintained that there was no devil in his land. 
This latter assertion is the more remarkable, as with savages the 
belief in bad spirits is far more common than that in good ones. 

of Civilization,' 1870. In a like manner Mr. Herbert Spencer, in his 
ingenious essay in the 'Fortnightly Review' (May 1st, 1870, p. 535), ac- 
counts for the earliest forms of religious belief throughout the world, 
by man being led through dreams, shadows, and other causes, to look 
at himself as a double essence, corporeal and spiritual. As the spiritual 
being is supposed to exist after death and to be powerful, it is propi- 
tiated by various gifts and ceremonies, and its aid invoked. He then 
further shows that names or nicknames given from some animal or 
other object, to the early progenitors or founders of a tribe, are sup- 
posed after a long interval to represent the real progenitor of the tribe; 
and such animal or object is then naturally believed still to exist as 
a spirit, is held sacred, and worshipped as a god. Nevertheless I can- 
not but suspect that there is a still earlier and ruder stage, when any- 
thing which manifests power or movement is thought to be endowed 
with some form of life, and with mental faculties analogous to our own. 



MENTAL POWERS. 93 

The feeling of religious devotion is a highly complex one, con- 
sisting of love, complete submission to an exalted and mysterious 
superior, a strong sense of dependence,^' fear, reverence, gratitude, 
hope for the future, and perhaps other elements. No being could 
experience so complex an emotion until advanced in his intellec- 
tual and moral faculties to at least a moderately high level. Never- 
theless, we see some distant approach to this state of mind in the 
deep love of a dog for his master, associated with complete sub- 
mission, some fear, and perhaps other feelings. The behavior 
of a dog when returning to his master after an absence, and. as 
I may add, of a monkey to his beloved keeper, is widely different 
from that towards their fellows. In the latter case the transports 
of joy appear to be somewhat less, and the sense of equality is 
shown in every action. Professor Braubach goes so far as to 
maintain that a dog looks on his master as on a god.^^ 

The same high mental faculties which first Jed man to believe 
in unseen spiritual agencies, then in fetishism, polytheism, and > 
ultimately in monotheism, would infallibly lead him, as long as 
his^ jeasoning powers remained poorly developed, to various 
"strange superstitions and customs. Many of these are terrible 
to think of — such as the sacrifice of human beings to a blood-lov- 
ing god; the trial of innocent persons by the ordeal of poison or 
fire; witchcraft, &c. — yet it is well occasionally to reflect on these 
superstitions, for they show us what an infinite debt of gratitude 
we owe to the improvement of our reason, to science, and to our 
accumulated knowledge. As Sir J. Lubbock^'' has well observed, 
"it is not too much to say that the horrible dread of unknown evil 
"hangs like a thick cloud over savage life, and embitters every 
"pleasure." These miserable and indirect consequences of our 
highest faculties may be compared with the incidental and occa- 
sional mistakes of the instincts of the lower animals. 

" See an able article on the 'Physical Elements of Religion,* by Mr. 
L. Owen Pike, in 'Anthropolog'. Review,' April, 1870, p. Ixiii. 

■^8 'Religion, Moral, &c., der Darwin'schen Art-Lehre,' 1869, s. 53. It 
is said (Dr. W. Lauder Lindsay, 'Journal of Mental Science,' 1871, p. 
43), that Bacon long ago, and the poet Burns, held the same notion. 

''^ 'Prehistoric Times,' 2nd edit. p. 571. In this work (p. 571) there will 
be found an excellent account of the many strange and capricious cus- 
toms of savages. 



94 THE DESCENT OF MAN. 



CHAPTER IV. 

COMPARISON OF THE MENTAL POWERS OF MAN AND 
THE LOWER ANIMALS— Continued. 

The moral sense — Fundamental proposition — The qualities of social 
animals — Origin of sociability — Struggle between opposed instincts — 
Man a social animal — The more enduring social instincts conquer 
other less persistent instincts — The social virtues alone regarded by 
savages — The self-regarding virtues acquired at a later stage of de- 
velopment—The importance of the judgment of the members of the 
same community on conduct— Transmission of moral tendencies- 
Summary. 

I fully subscribe to the judgment of those writers^ who main- 
tain that of all the differences between man and the lower animals, 
the moral sense or conscience is by far the most important. This 
sense, as Mackintosh^ remarks, "has a rightful supremacy over 
"every other principle of human action;" it is summed up in that 
short but imperious word ought, so full of high significance. It 
is the most noble of all the attributes of man, leading him with- 
out a moment's hesitation to risk his life for that of a fellow- 
creature; or after due deliberation, impelled simply by the deep 
feeling of right or duty, to sacrifice it in some great cause. Im- 
manuel Kant exclaims, "Duty! Wondrous thought, that workest 
"neither by fond insinuation, flattery, nor by any threat, but 
"merely by holding up thy naked law in the soul, and so extorting 
"for thyself always reverence, if not always obedience; before 
"whom all appetites are dumb, however secretly they rebel; 
"whence thy original?"^ 

This great question has been discussed by many writers* of 

1 See, for instance, on this subject, Quatrefages, 'Unite de I'Bspece 
Humaine,' 1861, p. 21, &c. 

2 'Dissertation on Ethical Philosophy,' 1837, p. 231, &c. 

3 'Metaphysics of Ethics,' translated by J. W. Semple, Edinburgh, 
1836, p. 136. 

* Mr. Bain gives a list ('Mental and Moral Science,' 1868, p. 543-725) of 
twenty-six British authors who have written on this subject, and 
whose names are familiar to every reader; to these, Mr. Bain's own 



MORAL SENSE. 95 

consummate ability; and my sole excuse for touching on it, is 
the impossibility of here passing it over; and because, as far as I 
know, no one has approached it exclusively from the side of 
natural history. The investigation possesses, also, some inde- 
pendent interest, as an attempt to see how far the study of the 
lower animals throws light on one of the highest psychical facul- 
ties of man. 

The following proposition seems to me in a high degree prob- 
able — namely, that any animal whatever, endowed with well- 
marked social instincts,^ the parental and filial affections being 
here included, would inevitably acquire a moral sense or con- 
science, as soon as its intellectual powers had become as well, 
or nearly as well developed, as in man. For, firstly, the social 
instincts lead an animal to take pleasure in the society of its 
fellows, to feel a certain amount of sympathy with them, and to 
perform various services for them. The services may be of a 
definite and evidently instinctive nature; or there may be only 
a wish and readiness, as with most of the higher social animals, 
to aid their fellows in certain general ways. But these feelings 
and services are by no means extended to all the individuals of 
the same species, only to those of the same association. Secondly, 
as soon as the mental faculties had become highly developed, 
images of all past actions and motives would be incessantly 
passing through the brain of each individual; and that feeling 
of dissatisfaction, or even misery, which invariably results, as we 

name, and those of Mr. Lecky, Mr. Shadworth Hodgson, Sir J. Lub- 
bock, and others, might be added. 

2 Sir B. Brodie, after observing that man is a social animal ('Psy- 
chological Enquiries,' 1854, p. 192), asks the pregnant question, "ought 
"not this to settle the disputed question as to the existence of a moral 
"sense?" Similar ideas have probably occurred to many persons, as 
they did long ago to Marcus Aurelius. Mr. J. S. Mill speaks, in his 
celebrated work, 'Utilitarianism,' (1864, pp. 45, 46), of the social feelings 
as a "powerful natural sentiment," and as "the natural basis of senti- 
"ment for utilitarian morality." Again he says, "Like the other ac- 
"quired capacities above referred to, the moral faculty, if not a part of 
"our nature, is a natural out-growth from it; capable, like them, in a 
"certain small degree of springing up spontaneously." But in oppo- 
sition to all this, he also remarks, "if, as is my own belief, the moral 
"feelings are not innate, but acquired, they are not for that reason less 
"natural." It is with hesitation that I venture to differ at all from so 
profound a thinker, but it can hardly be disputed that the social feel- 
ings are instinctive or innate in the lower animals; and why should 
they not be so in man? Mr. Bain (see, for instance, 'The Emotions and 
the Will,' 1865, p. 481) and others believe that the moral sense is ac- 
quired by each individual during his lifetime. On the general theory 
of evolution this is at least extremely improbable. The ignoring of all 
transmitted mental qualities will, as it seems to me, be hereafter 
judged as a most serious blemish in the works of Mr. Mill. 



96 THE DESCENT OF MAN. 

shall hereafter see, from any unsatisfied instinct, would arise, 
as often as it was perceived that the enduring and alvsrays present 
social instinct had yielded to some other instinct, at the time 
stronger, but neither enduring in its nature, nor leaving behind 
it a very vivid impression. It is clear that many instinctive de- 
sires, such as that of hunger, are in their nature of short dura- 
tion; and after being satisfied, are not readily or vividly recalled. 
Thirdly, after the power of language had been acquired, and the 
wishes of the community could be expressed, the common opinion 
how each member ought to act for the public good, would natural- 
ly become in a paramount degree the guide to action. But it 
should be borne in mind that however great weight we may attrib- 
ute to public opinion, our regard for the approbation and dis- 
approbation of our fellows depends on sympathy, which, as we 
shall see, forms an essential part of the social instinct, and is 
indeed its foundation-stone. Lastly, habit in the individual would 
ultimately play a very important part in guiding the conduct of 
each member; for the social instinct, together with sympathy, 
is, like any other instinct, greatly strengthened by habit, and so 
consequently would be obedience to the wishes and judgment of 
the community. These several subordinate propositions must now 
be discussed, and some of them at considerable length. 

It may be well first to premise that I do not wish to maintain 
that any strictly social animal, if its intellectual faculties were 
to become as active and as highly developed as in man, v/ould 
acquire exactly the same moral sense as ours. In the same man- 
ner as various animals have some sense of beauty, though they 
admire widely different objects, so they might have a sense of 
right and wrong, though led by it to follow widely different lines 
of conduct. If, for instance, to take an extreme case, men were 
reared under precisely the same conditions as hive-bees, there 
can hardly be a doubt that our unmarried females would, like 
the worker-bees, think it a sacred duty to kill their brothers, and 
mothers would strive to kill their fertile daughters; and no one 
would think of interfering." Nevertheless, the bee, or any other 



« Mr. H. Sidg-wick remarks in an able discussion on this subject (the 
'Academy,' June 15th, 1872, p. 231), "a superior bee, we may feel sure, 
"would aspire to a milder solution of the population question." Judg- 
ing, however, from the habits of many or most savages, man solves the 
problem by female infanticide, polyandry and promiscuous inter- 
course; therefore it may well be doubted whether it would be by a 
milder method. Miss Cobbe, in commenting ('Darwinism in Morals,' 
'Theological Review,' April, 1872, p. 188-191) on the same illustration, 
says, the principles of social duty would be thus reversed; and by this, 
I presume, she means that the fulfillment of a social duty would tend 
to the injury of individuals; but she overlooks the fact, which she 
would doubtless admit, that the instincts of the bee have been ac- 



MORAL SENSE. 97 

social animal, would gain in our supposed case, as it appears to 
me, some feeling of right or wrong, or a conscience. For each in- 
dividual would have an inward sense of possessing certain 
stronger or more enduring instincts, and others less strong or 
enduring; so that there would often be a struggle as to which 
impulse should be followed; and satisfaction, dissatisfaction, or 
even misery would be felt, as past impressions were compared 
during their incessant passage through the mind. In this case 
an inward monitor would tell the animal that it would have been 
better to have followed the one impulse rather than the other. 
The one course ought to have been followed, and the other ought 
not; the one would have been right and the other wrong; but to 
these terms I shall recur. 

Sociability. — Animals of many kinds are social; we find even 
distinct species living together; for example, some American 
monkeys; and united flocks of rooks, jackdaws, and starlings. 
Man shows the same feeling in his strong love for the dog, which 
the dog returns with interest. Every one must have noticed how 
miserable horses, dogs, sheep, &c., are when separated from 
their companions, and what strong mutual affection the two 
former kinds, at least, show on their reunion. It is curious to 
speculate on the feelings of a dog, who will rest peacefully for 
hours in a room with his master or any of the family, without 
the least notice being taken of him; but if left for a short time 
by himself, barks or howls dismally. We will confine our atten- 
tion to the higher social animals; and pass over insects, although 
some of these are social, and aid one another in many important .;jf 

ways. The most common mutual service in the higher animals 
is to warn one another of danger by means of the united senses 1 
of all. Every sportsman knows, as Dr. Jaeger remarks," how diffi- 
cult it is to approach animals in a herd or troop. Wild horses 
and cattle do not, I believe, make any danger-signal; but the 
attitude of any one of them who first discovers an enemy, warns 
the others. Rabbits stamp loudly on the ground with their hind- 
feet as a signal: sheep and chamois do the same with their fore- 
feet, uttering likewise a whistle. Many birds, and some mam- 
mals, post sentinels, which in the case of seals are said^ generally 
to be the females. The leader of a troop of monkeys acts as the sen- 
quired for the good of the community. She goes so far as to say that 
if the theory of ethics advocated in this chapter were ever generally 
accepted, "I cannot but believe that in the hour of their triumph would 
"be sounded the knell of the virtue of mankind!" It is to be hoped 
that the belief in the permanence of virtue on this earth is not held by 
many persons on so weak a tenure. 

■7 'Die Darwin' sche Theorie,' s. 101. 

8 Mr. R. Brown in 'Froc. Zoolog. Soc' 1868, p. 4(». 



98 THE DESCENT OF MAN. 

tinel, and utters cries expressive both of danger and of safety." 
Social animals perform many little services for each other: horses 
nibble, and cows lick each other, on any spot which itches: monk- 
eys search each other for external parasites; and Brehm states 
that after a troop of the Cercopithecus griseo-viridis has rushed 
through a thorny brake, each monkey stretches itself on a branch, 
and another monkey sitting by, "conscientiously" examines its 
fur, and extracts every thorn or burr. 

Animals also render more important services to one another: 
thus wolves and some other beasts of prey hunt in packs, and 
aid one another in attacking their victims. Pelicans fish in con- 
cert. The Hama'dryas baboons turn over stones to find insects, 
&c.; and when they come to a large one, as many as can stand 
round, turn it over together and share the booty. Social animals 
mutually defend each other. Bull bisons in N. America, when 
there is danger, drive the cows and calves into the middle of the 
herd, whilst they defend the outside. I shall also in a future chap- 
ter give an account of two young wild bulls at Chillingham at- 
tacking an old one in concert, and of two stallions together trying 
to drive av/ay a third stallion from a troop of mares. In Abyssinia, 
Brehm encountered a great troop of baboons, who were crossing 
a valley: some had already ascended the opposite mountain, and 
some were still in the valley: tlie latter were attacked by the 
dogs, but the old males immediately hurried down from the rocks, 
and with mouths widely opened roared so fearfully, that the dogs 
quickly drew back. They were again encouraged to the attack; 
but by this time all the baboons had reascended the heights, ex- 
cepting a young one, about six months old, who, loudly calling 
for aid, climbed on a block of rock, and was surrounded. Now 
one of the largest males, a true hero, came down again from the 
mountain, slowly went to the young one, coaxed him, and trium- 
phantly led him away — the dogs being too much astonished to 
make an attack. I cannot resist giving another scene which was 
witnessed by this same naturalist; an eagle seized a young Cerco- 
pithecus, which, by clinging to a branch, was not at once carried 
off; it cried loudly for assistance, upon which the other members 
of the troop, with much uproar, rushed to the rescue, surrounded 
the eagle, and pulled out so many feathers, that he no longer 
thought of his prey, but only how to escape. This eagle, as Brehm 

8 Brehm, 'Thierleben,' B. i. 1864, s. 52, 79. For the case of the mon- 
keys extracting thorns from each other, see s. 54. With respect to the 
Hamadryas turning over stones, the fact is given (s, 76) on the evi- 
dence of Alvarez, whose observations Brehm thinks quite trustworthy. 
For the cases of the old male baboons attacking the dogs, see s. 79; 
and with respect to the eagle, s. 56. 



MORAL. SENSE. 99 

remarks, assuredly would never again attack a single monkey of 
a troop.^" 

It is certain that associated animals have a feeling of love for 
each other, which is not felt by non-social adult animals. How 
far in most cases they actually sympathize in the pains and 
pleasures of others, is more doubtful, especially with respect to 
pleasures. Mr. Buxton, however, who had excellent means of 
observation,^^ states that his macaws, which lived free in Norfolk, 
took "an extravagant interest" in a pair with a nest; and when- 
ever the female left it, she was surrounded by a troop "scream- 
"ing horrible acclamations in her honor." It is often difficult 
to judge whether animals have any feeling for the sufferings of 
others of their kind. Who can say what cows feel, when they 
surround and stare intently on a dying or dead companion; ap- 
parently, however, as Houzeau remarks, they feel no pity. That 
animals sometimes are far from feeling any sympathy is too 
certain; for they will expel a wounded animal from the herd, or 
gore or worry it to death. This is almost the blackest fact in 
natural history, unless, indeed, the explanation which has been 
suggested is true, that their instinct or reason leads them to expel 
an injured companion, lest beasts of prey, including man, 
should be tempted to follow the troop. In this case their con- 
duct is not much worse than that of the North American Indians, 
who leave their feeble comrades to perish on the plains: or the 
Fijians, who, when their parents get old, or fall ill, bury them 
alive." 

Many animals, however, certainly sympathize with each other's 
distress or danger. This is the case even with birds. Capt. Stans- 
Ijui-yis found on a salt lake in Utah an old and completely blind 
pelican, which was very fat, and must have been well fed for a 
long time by his companions. Mr. Blyth, as he informs me, saw 
Indian crows feeding two or three of their companions which were 
blind; and I have heard of an analogous case with the domestic 

10 Mr. Belt gives the case of a spider-monkey (Ateles) in Nicara- 
gua which was heard screaming for nearly two hours in the forest, 
and was found with an eagle perched close by it. The bird apparently 
feared to attack as long as it remained face to face; and Mr. Belt be- 
lieves, from what he has seen of the habits of these monkeys, that they 
protect themselves from eagles by keeping two or three together. 'The 
Naturalist in Nicaragua,' 1874, p. 118. 

n 'Annals and Mag. of Nat. Hist.,* November, 1868, p. 382. 

12 Sir J. Lubbock, 'Prehistoric Times,' 2nd edit. p. 446. 

13 As quoted by Mr. L. H. Morgan, 'The American Beaver,* 1868, p. 
272. Capt. Stansbury also gives an interesting account of the manner 
in which a very young pelican, carried away by a strong stream, was 
guided and encouraged in its attempts to reach the shore by half a 
dozen old birds. 



100 THE DESCENT OF MAN. 

cock. We may, if we choose, call these actions instinctive; but 
such cases are much too rare for the development of any special 
instinct/* I have myself seen a dog, who never passed a cat who 
lay sick in a basket, and was a great friend of his, without giving 
her a few licks with his tongue, the surest sign of kind feeling in 
a dog. 

It must be called sympathy that leads a courageous dog to 
fly at any one who strikes his master, as he certainly will. I 
saw a person pretending to beat a lady, who had a very timid 
little dog on her lap, and the trial had never been made before; 
the little creature instantly jumped away, but after the pretended 
beating was over, it was really pathetic to see how per&everingly 
he tried to lick his mistress's face, and comfort her. Brehm^* 
states that when a baboon in confinement was pursued to be 
punished, the others tried to protect him. It must have been 
sympathy in the cases above given which led the baboons and 
Cercopitheci to defend their young comrades from the dogs and 
the eagle. I will give only one other instance of sympathetic 
and heroic conduct, in the case of a little American monkey. 
Several years ago a keeper at the Zoological Gardens showed me 
some deep and scarcely healed wounds on the nape of his own 
neck, inflicted on him, whilst kneeling on the floor, by a fierce 
baboon. The little American monkey, who was a warm friend of 
this keeper, lived in the same large compartment, and was dread- 
fully afraid of the great baboon. Nevertheless, as soon as he saw 
his friend in peril, he rushed to the rescue, and by screams and 
bites so distracted the baboon that the man was able to escape, 
after, as the surgeon thought, running great risk of his life. 

Besides love and sympathy, animals exhibit other qualities 
connected with social instincts, which in us would be called moral ; 
and I agree with Agassiz^^ that dogs possess something very like 
a conscience. 

Dogs possess some power of self-command, and this does not 
appear to be wholly the result of fear. As Braubach" remarks, 
they will refrain from stealing food in the absence of their mas- 
ter. They have long been accepted as the very type of fidelity 
and obedience. But the elephant is likewise very faithful to his 
driver or keeper, and probably considers him as the leader of 
the herd. Dr. Hooker informs me that an elephant, which he was 
riding in India, became so deeply bogged that he remained stuck 
fast until the next day, when he was extricated by men with 
ropes. Under such circumstances elephants will seize with their 

1* As Mr. Bain states, "effective aid to a sufferer springs fronu. sym- 
"pathy proper;" 'Mental and Moral Science,' 1868, p. 245. 
15 'Thierleben, B. i. s. 85. 
18 'De I'Espece et de la Classe,' 1869, p. 97. 
1^ 'Die Darwin' schfe Art-Dehre,' 1869, s. 54. 



MORAL SENSE. 101 

trunks any object, dead or alive, to place under their knees, to 
prevent their sinking deeper in the mud; and the driver was 
dreadfully afraid lest the animal should have seized Dr. Hooker 
and crushed him to death. But the driver himself, as Dr. Hooker 
was assured, ran no risk. This forbearance under an emergency 
so dreadful for a heavy animal, is a wonderful proof of noble 
fidelity.^^ 

All animals living in a body, which defend themselves or attack 
their enemies in concert, must indeed be in some degree faithful 
to one another; and those that follow a leader must be in some 
degree obedient. When the baboons in Abyssinia^^ plunder a 
garden, they silently follow their leader; and if an imprudent 
young animal makes a noise, he receives a slap from the others 
to teach him silence and obedience. Mr. Galton, who has had 
excellent opportunities for observing the half-wild cattle in S. 
Africa, says,-'^ that they cannot endure even a momentary separa- 
tion from the herd. They are essentially slavish, and accept the 
common determination, seeking no better lot than to be led by 
any one ox who has enough self-reliance to accept the position. 
The men who break in these animals for harness, watch assidu- 
ously for those who, by grazing apart, show a self-reliant dis- 
position, and these they train as fore-oxen. Mr. Galton adds 
that such animals are rare and valuable; and if many were born 
they would soon be eliminated, as lions are always on the look- 
out for the individuals wnich wander from the herd. 

With respect to tne impulse which leads certain animals to 
associate together, and to aid one another in many ways, we may 
infer that in most cases they are impelled by the same sense of 
satisfaction or pleasure which they experience in performing 
other instinctive actions; or by the same sense of dissatisfaction 
as when other instinctive actions are checked. We see this in 
innumerable instances, and it is illustrated in a striking manner 
by the acquired instincts of our domesticated animals; thus a 
young shepherd-dog delights in driving and running round a 
flock of sheep, but not in worrying them; a young fox-hound de- 
lights in hunting a fox, whilst some other kinds of dogs, as I have 
witnessed, utterly disregard foxes. What a strong feeling of 
inward satisfaction must impel a bird, so full of activity, to brood 
day after day over her eggs. Migratory birds are quite miserable 
if stopped from migrating; perhaps they enjoy starting on their 
long flight; but it is hard to believe that the poor pinioned goose, 
described by Audubon, which started on foot at the proper time 
for its journey of probably more than a thousand miles, could 

^^ See also Hooker's 'Himalayan Journals,' vol. ii., 1854, p. 333. 
1® Brehm, 'Thierleben,' B. i. s. 76. 

^ See his extremely interesting- paper on 'Gregarlousness in Cattle, 
and in man,* 'Macmilian's Meg." Feb. 1871, p. 353. 
8 



102 THE DESCENT OF MAN. 

have felt any joy in doing so. Some instincts are determine<< 
solely by painful feelings, as by fear, which leads to self-preserva- 
tion, and is in some cases directed towards special enemies. No 
one, I presume, can analyze the sensations of pleasure or pain. 
In many instances, however, it is probable that instincts are per- 
sistently followed from the mere force of inheritance, without the 
stimulus of either pleasure or pain. A young pointer, when it 
first scents game, apparently cannot help pointing. A squirrel 
in a cage who pats the nuts which it cannot eat, as if to bury them 
in the ground, can hardly be thought to act thus, either from 
pleasure or pain. Hence the common assumption that men must 
be impelled to every action by experiencing some pleasure or pain 
may be erroneous. Although a habit may be blindly and im- 
plicitly followed, independently of any pleasure or pain felt at the 
moment, yet if it be forcibly and abruptly checked, a vague sense 
of dissatisfaction is generally experienced. 

It has often been assumed that animals were in the first place 
rendered social, and that they feel as a consequence uncomfortable 
when separated from each other, and comfortable whilst together; 
but it is a more probable view that these sensations were first 
developed, in order that those animals which would profit by liv- 
ing in society, should be induced to live together, in the same 
manner as the sense of hunger and the pleasure of eating v/ere. 
no doubt, first acquired in order to induce animals to eat. The 
tfeeling of pleasure from society is probably an extension of the 
Iparental or filial affections, since the social instinct seems to be 
developed by the young remaining for a long time with their 
parents; and this extension may be attributed in part to habit, 
but chiefly to natural selection. With those animals which were 
benefited by living in close association, the individuals which 
took the greatest pleasure in society would best escape various 
dangers; whilst those that cared least for their comrades, and 
lived solitary, would perish in greater numbers. With respect to 
the origin of the parental and filial affections, which apparently 
lie at the base of the social instincts, we know not the steps by 
which they have been gained; but we may infer that it has been 
to a large extent through natural selection. So it has almost 
certainly been with the unusual and opposite feeling of hatred 
between the nearest relations, as with the worker-bees which kill 
their brother-drones, and with the queen-bees which kill their 
daughter-queens; the desire to destroy their nearest relations 
having been in this case of service to the community. Parental 
affection, or some feeling which replaces it, has been developed 
in certain animals extremely low in the scale, for example, in 
star-fishes and spiders. It is also occasionally present in a few 
members alone in a whole group of animals, as in the genus For- 
ficula, or earwigs. 



MORAL SENSE. 103 

The all-important emotion of sympathy is distinct from that 
of love. A mother may passionately love her sleeping and passive 
infant, but she can hardly at such times be said to feel sympathy 
for it. The love of a man for his dog is distinct from sympathy, 
and so is that of a dog for his master. Adam Smith formerly 
argued, as has Mr. Bain recently, that the basis of sympathy lies 
in our strong retentiveness of former states of pain or pleasure. 
Hence, "the sight of another person enduring hunger, cold, fa- 
"tigue, revives in us some recollection of these states, which are 
"painful even in idea." We are thus impelled to relieve the suf- 
ferings of another, in order that our own painful feelings may be 
at the same time relieved. In like manner we are led to partici- 
pate in the pleasures of others.^^ But I cannot see how this view 
explains the fact that sympathy is excited, in an immeasurably 
stronger degree, by a beloved, than by an indifferent person. The 
mere sight of suffering, independently of love, would suffice to call 
up in us vivid recollections and associations. The explanation 
may lie in the fact that, with all animals, sympathy is directed 
solely towards the members of the same community, and therefore 
towards known, and more or less beloved members, but not to all 
the individuals of the same species. This fact is not more sur- 
prising than that the fears of many animals should be directed 
against special enemies. Species which are not social, such as 
lions and tigers, no doubt feel sympathy for the suffering of their 
own young, but not for that of any other animal. With mankind, 
selfishness, experience, and imitation, probably add, as Mr. Bain 
has shown, to the power of sympathy; for we are led by the hope 
of receiving good in return to perform acts of sympathetic kind- 
ness to others; and sympathy is much strengthened by habit. In 
however complex a manner this feeling may have originated, as 
it is one of high importance to all those animals which aid and 
defend one another, it will have been increased through natural 
selection; for those communities, which included the greatest 
number of the most sympathetic members, would flourish best, 
and rear the greatest number of offspring. 

It is, however, impossible to decide in many cases whether cer- 
tain social instincts have been acquired through natural selection, 
or are the indirect result of other instincts and faculties, such as 

21 See the first and striking chapter in Adam Smith's 'Theory of 
Moral Sentiments.' Also Mr. Bain's 'Mental and Moral Science,' 1868, p. 
244, and 275-282. Mr. Bain states, that "sympathy is, indirectly, a 
"source of pleasure to the sympathizer;" and he accounts for this 
through reciprocity. He remarks that "the person benefited, or others 
"in his stead, may make up by sympathy and good offices returned, for 
"all the sacrifice." But if, as appears to be the case, sympathy is strictly 
an instinct, its exercise would give direct pleasure in the same manner, 
as the exercise, as before remarked, of almost every other instinct. 



104 THE DESCENT OF MAN. 

sympathy, reason, experience, and a tendency to imitation; or 
again, whether they are simply the result of long-continued habit. 
So remarkable an instinct as the placing sentinels to warn the 
community of danger, can hardly have been the indirect result 
of any of these faculties; it must, therefore, have been directly 
acquired. On the other hand, the habit followed by the males of 
some social animals of defending the community, and of attacking 
their enemies or their prey in concert, may perhaps have orig- 
inated from mutual sympathy; but courage, and in most cases 
strength, must have been previously acquired, probably through 
natural selection. 

Of the various instincts and habits, some are much stronger 
than others; that is, some either give more pleasure in their per- 
formance, and more distress in their prevention, than others, or, 
which is probably quite as important, they are, through inherit- 
ance, more persistently followed, without exciting any special feel- 
ing of pleasure or pain. We are ourselves conscious that some hab- 
-its are much more difficult to cure or change than others. Hence a 
struggle may often be observed in animals between different in- 
stincts, or between an instinct and some habitual disposition; as 
when a dog rushes after a hare, is rebuked, pauses, hesitates, pur- 
sues again, or returns ashamed to his master; or as between the 
love of a female dog for her young puppies and for her master, 
— for she may be seen to slink away to them, as if half ashamed 
of not accompanying her master. But the most curious instance 
known to me of one instinct getting the better of another, is the 
migratory instinct conquering the maternal instinct. The former 
is wonderfully strong; a confined bird will at the proper season 
beat her breast against the wires of her cage, until it is bare and 
bloody. It causes young salmon to leap out of the fresh water, in 
which they could continue to exist, and thus unintentionally to 
commit suicide. Every one knows how strong the maternal in- 
stinct is, leading even timid birds to face great danger, though 
with hesitation, and in opposition to the instinct of self-preserva- 
tion. Nevertheless, the migratory instinct is so powerful, that 
late in the autumn swallows, house-martins, and swifts frequently 
desert their tender young, leaving them to perish miserably in 
their nests.-^ 

^2 This fact, the Rev. L. Jenyns states (see his edition of 'White's 
Nat. Hist, of Selborne,' 1853, p. 204) was first recorded by the illustrious 
Jenner, in 'Phil. Transact.' 1824, and has since fceen confirmed by sev- 
eral observers, especially by Mr. Blackwall. This latter careful ob- 
server examined late in the autumn, during two years, thirty-six nests; 
he found that twelve contained young- dead birds, five contained eggs 
on the point of being hatched, and three eggs not nearly hatched. 
Many birds not yet old enough for a prolonged flight, are likewise 
desierted and lieift b'efiind. Steb Blaokwall, 'Researches in ZoolDgy,' 1834, 



MORAL SENSE. 105 

We can perceive that an instinctive impulse, if it be in any- 
way more beneficial to a species than some other or opposed 
instinct, would be rendered the more potent of the two through 
natural selection; for the individuals which had it most strongly 
developed would survive in larger numbers. Whether this is the 
case with the migratory in comparison with the maternal instinct, 
may be doubted. The great persistence, or steady action of the 
former at certain seasons of the year during the whole day, may 
give it for a time paramount force. 

Man a social animal. — Every one will admit that man is a 
social being. We see this in his dislike of solitude, and in his 
wish for society beyond that of his own family. Solitary con- 
finement is one of the severest punishments which can be inflicted. 
Some authors suppose that man primevally lived in single fami- 
lies; but at the present day, though single families, or only two 
or three together, roam the solitudes of some savage lands, they 
always, as far as I can discover, hold friendly relations with 
other families inhabiting the same district. Such families oc- 
casionally meet in council, and unite for their common de- 
fense. It is no argument against savage man being a social ani- 
mal, that the tribes inhabiting adjacent districts are almost al- 
ways at war with each other; for the social instincts never ex- 
tend to all the individuals of the same species. Judging from the 
analogy of the majority of the Quadrumana, it is probable that 
the early ape-like progenitors of man v/ere likewise social; but 
this is not of much importance for us. Although man, as he 
now exists, has few special instincts, having lost any which his 
early progenitors may have possessed, this is no reason why he 
should not have retained from an extremely remote period some 
degree of instinctive love and sympathy for his fellows. We 
are indeed all conscious that we do possess such sympathetic 
feelings;^ but our consciousness does not tell us whether they 
are instinctive, having originated long ago in the same manner 
as with the lower animals, or whether they have been acquired 
by each of us during our early years. As man is a social animal, 

pp. 108, 118. For some additional evidence, althoug-h this is not wanted, 
see Leroy, 'Lettres Pliil.' 1802, p. 217. For Swifts, Goulds, 'IntrodLiction 
to the Birds of Great Britain,' 1823, p. 5. Similar cases have been ob- 
served in Canada by Mr. Adams; 'Pop. Science Review,' July, 1873, 
p. 283. 

23 Hume remarks ('An Enquiry Concerning the Principles of Morals,' 
edit, of 1751, p. 132). "There seems a necessity for confessing that the 
"happiness and misery of others are not spectacles altogether indiffer- 
"ent to us, but that the view of the former . , . communicates a secret 
"joy; the appearance of the latter . . . throws a melancholy damp 
"over the imagination." 



106 THE DESCENT OF MAN. 

it is almost certain that he would inherit a tendency to be faith- 
ful to his comrades, and obedient to the leader of his tribe for 
these qualities are common to most social animals. He would 
consequently possess some capacity for self-command. He 
would from an inherited tendency be willing to defend, in con- 
cert with others, his fellow-men; and would be ready to aid 
them in any way, which did not too greatly interfere with his 
own welfare or his own strong desires. 

The social animals which stand at the bottom of the scale are 
guided almost exclusively, and those which stand higher in the 
scale are largely guided, by special instincts in the aid which 
they give to the members of the same community; but they are 
likewise in part impelled bj;^ mutual love and sympathy, assisted 
apparently by some amount of reason. Although man, as just 
remarked, has no special instincts to tell him how to aid his 
fellow-men, he still has the impulse, and with his improved 
intellectual faculties would naturally be much guided in this re- 
spect by reason and experience. Instinctive sympathy would 
also cause him to value highly the approbation of his fellows; 
for, as Mr. Bain has clearly shown,-* the love of praise and the 
strong feeling of glory, and the still stronger horror of scorn 
and infamy, "are due to the workings of sympathy." Conse- 
quently man would be influenced in the highest degree by the 
wishes, approbation, and blame of his fellow-men, as expressed 
by their gestures and language. Thus the social instincts, 
which must have been acquired by man in a very rude state, 
and probably even by his early ape-like progenitors, still give 
the impulse to some of his best actions; but his actions are in a 
higher degree determined by the expressed wishes and judgment 
of his fellow-men, and unfortunately very often by his own 
strong selfish desires. JBut as love, sympathy and self-command 
become strengthened by habit, and as the power of reasoning 
becomes clearer, so that man can value justly the judgments of 
his fellows, he will feel himself impelled, apart trom any transi- 
tory pleasure or pain, to certain lines of conduct. He might 
then declare — not that any barbarian or uncultivated man could 
thus think — I am the supreme judge of my own conduct, and in 
the words of Kant, I will not in my own person violate the 
dignity of humanity. 

The more enduring Social Instincts conquer the less persistent 
Instincts. — We have not, however, as yet considered the main 
point, on which, from our present point of view, the whole 
question of the moral sense turns. Why should a man feel that 
he ought to obey one instinctive desire rather than another? 

24 'Mental and Moral Science,' 1868, p. 254. 



MORAL SENSE. 107 

Why is he bitterly regretful, if he has yielded to a strong sense 
of self-preservation, and has not risked his life to save that of a 
fellow-creature? or why does he regret having stolen food from 
hunger? 

It is evident in the first place, that with mankind the instinc- 
tive impulses have different degrees of strength; a savage will 
risk his own life to save that of a member of the same com- 
munity, but will be wholly indifferent about a stranger: a young 
and timid mother urged by the maternal instinct will, without 
a moment's hesitation, run the greatest danger for her own in- 
fant, but not for a mere fellow-creature. Nevertheless many a 
civilized man, or even boy, who never before risked his life for 
another, but full of courage and sympathy, has disregarded 
the instinct of self-preservation, and plunged at once into a 
torrent to save a drowning man, though a stranger. In this case 
man is impelled by the same instinctive motive, which made the 
heroic little American monkey, formerly described, save his 
keeper, by attacking the great and dreaded baboon. Such ac- 
tions as the above appear to be the simple result of the greater 
strength of the social or maternal instincts than that of any 
other instinct or motive; for they are performed too instan- 
taneously for reflection, or for pleasure or pain to be felt at the 
time; though, if prevented by anj^ cause, distress or even misery 
might be felt. In a timid man, on the other hand, the instinct 
of self-preservation might be so strong, that he would be unable 
to force himself to run any such risk, perhaps not even for his 
own-child. 

I am aware that some persons maintain that actions performed 
impulsively, as in the above cases, do not come under the do- 
minion of the moral sense, and cannot be called moral. They 
confine this term to actions done deliberately, after a victory 
over opposing desires, or when prompted by some exalted mo- 
tive. But it appears scarcely possible to draw any clear line 
of distinction of this kind.-^ As far as exalted motives are 
concerned, many instances have been recorded of savages, des- 
titute of any feeling of general benevolence towards mankind, 
and not guided by any religious motive, who have deliberately . 
sacrificed their lives as prisoners,^** rather than betray their ^; 

25 1 refer here to the distinction between what has been called ma- 
terial and formal morality. I am glad to And that Prof. Huxley 
('Critiques and Addresses,' 1873, p. 287) takes th© same view on this 
subject as I do. Mr. Leslie Stephen remarks ('Essays on Preethinking- 
and Plain Speaking,' 1873, p. S3), "the metaphysical distinction be- 
"tween material and formal morality is as irrelevant as other such dis- 
"tinctions." 

^ I have given on© such case, namely of three Patagoniaa Indians 



108 THE DESCENT OP MAN. 

comrades; and surely their conduct ought to be considered as 
moral. As far as deliberation, and the victory over opposing 
motives are concerned, animals may be seen doubting between 
opposed instincts, in rescuing their offspring or comrades from 
danger; yet their actions, though done for the good of others, 
are not called moral. Moreover, anything performed very often 
by us, will at last be done without deliberation or hesitation, 
and can then hardly be distinguished from an instinct; yet 
surely no one will pretend that such an action ceases to be 
moral. On the contrary, we all feel that an act cannot be 
considered as perfect, or as performed in the most noble manner, 
unless it be done impulsively, without deliberation or effort, in 
the same manner as by a man in whom the requisite qualities are 
innate. He who is forced to overcome his fear or want of sym- 
pathy before he acts, deserves, however, in one way higher 
credit than the man whose innate disposition leads him to a 
good act without effort. As we cannot distinguish between 
motives, we rank all actions of a certain class as moral, if per- 
formed by a moral being. A moral being is one who is capable 
of comparing his past and future actions or motives, and of 
approving or disapproving of them. We have no reason to sup- 
pose that any of the lower animals have this capacitj'-; there- 
fore, when a Newfoundland dog drags a child out of the water, 
or a monkey faces danger to rescue its comrade, or takes charge 
of an orphan monkey, we do not call its conduct moral. But 
in the case of man, who alone can with certainty be ranked 
as a moral being, actions of a certain class are called moral, 
whether performed deliberately, after a struggle with opposing 
motives, or impulsively through instinct, or from the effects of 
slowly-gained habit. 

But to return to our more immediate subject. Although some 
instincts are more powerful than others, and thus lead to cor- 
responding actions, yet it is untenable, that in man the social 
instincts (including the love of praise and fear of blame) possess 
greater strength, or have, through long habit, acquired greater 
strength than the instincts of self-preservation, hunger, lust, 
vengeance, &c. Why then does man regret, even though trying 
to banish such regret, that he has followed the one natural 
impulse rather than the other; and why does he further feel 
that he ought to regret his conduct? Man in this respect differs 
profoundly from the lower animals. Nevertheless we can I think, 
see with some degree of clearness the reason of this difference. 

Man, from the activity of his mental faculties, cannot avoid 
reflection: past impressions and images are incessantly and 

who preferred being shot, one after the other, to betraying the plans 
Of their companions in war ('Journai of Researches,' 1845, p. 103), 



MORAL SENSE. 109 

clearly passing through his mind. Now with those animals 
which live permanently in a body, the social instincts are ever 
present and persistent. Such animals are always ready to utter 
the danger-signal, to defend the community, and to give aid to 
their fellows in accordance with their habits; they feel at all 
times, without the stimulus of any special passion or desire, 
some degree of love and sympathy for them; they are unhappy 
if long separated from them, and always happy to be again in 
their company. So it is with ourselves. Even when we are 
quite alone, how often do we think with pleasure or pain of what 
others think of us, — of their imagined approbation or disappro- 
bation; and this all follows from sympathy, a fundamental 
element of the social instincts. A man who possessed no trace 
of such instincts would be an unnatural monster. On the other 
hand, the desire to satisfy hunger, or any passion such as ven- 
geance, is in its nature temporary, and can for a time be fully 
satisfied. Nor is it easy, perhaps hardly possible, to call up 
with complete vividness the feeling, for instance, of hunger; nor 
indeed, as has often been remarked, of any suffering. The in- 
stinct of self-preservation is not felt except in the presence of 
danger; and many a coward has thought himself brave until he 
has met his enemy face to face. The wish for another man's 
property is perhaps as persistent a desire as any that can be 
named; but even in this case the satisfaction of actual pos- 
session is generally a weaker feeling than the desire: many a 
thief, if not a habitual one, after success has v/ondered why he 
stole some article." 



27 Enmity or hatred seems also to be a highly persistent feeling, per- 
haps more so than any other that can be named. Envy is defined as 
hatred of another for some excellence or success; and Bacon insists 
(Essay ix.), "Of all other aifections envy is the most importune and 
"continual." Dogs are very apt to hate both strange men and strange 
dogs, especially if they live near at hand, but do not belong to the same 
family, tribe, or clan; this feeling would thus seem to be innate and 
is certainly a most persistent one. It seems to be the complement and 
converse of the true social instinct. From what we hear of savages, 
it would appear that something of the same kind holds good with them. 
If this be so, it would be a small step in any one to transfer such 
feelings to any member of the same tribe if he had done him an 
injury and had become his enemy. Nor is it probable that the prim- 
itive conscience would reproach a man for injuring his enemy: rather 
it would reproach him if he had not revenged himself. To do good in 
return for evil, to love your enemy, is a height of morality to which 
it may be doubted whether the social instincts would, by themselves, 
have ever led us. It is necessary that these instincts, together with 
sympathy, should have been highly cultivated and extended by the aid 
of reason, instruction, and the love or fear of God before any such 
golden rule would ever be thought of and obeyed. 



110 THE DESCENT OF MAN. 

A man cannot prevent past impressions often repassing 
through his mind; he will thus be driven to make a comparison 
between the impressions of past hunger, vengeance satisfied, or 
danger shunned at other men's cost, with the almost ever-present 
instinct of sympathy, and with his early knowledge of what others 
consider as praisev/orthy or blamable. This knowledge can- 
not be banished from his mind, and from instinctive sympathy 
is esteemed of great moment. He will then feel as if he had 
been balked in following a present instinct or habit, and this 
with all animals causes dissatisfaction, or even misery. 

The above case of the swallow affords an illustration, though 
of a reversed nature, of a temporary though for the time strongly 
persistent instinct conquering another instinct, which is usually 
dominant over all others. At the proper season these birds 
seem all day long to be impressed with the desire to migrate; 
their habits change; they become restless, are noisy, and con- 
gregate in flocks. "Whilst the mother-bird is feeding, or brood- 
ing over her nestlings, the maternal instinct is probably stronger 
than the migratory; but the instinct which is the more persist- 
ent gains the victory, and at last, at a moment when her young 
ones are not in sight, she takes flight and deserts them. When 
arrived at the end of her long journey, and the migratory in- 
stinct has ceased to act, what an agony of remorse the bird 
would feel, if, from being endowed with great mental activity, 
she could not prevent the image constantly passing through her 
mind, of her young ones perishing in the bleak north from cold 
and hunger. 

At the moment of action, man will no doubt be apt to follow 
the stronger impulse; and though this may occasionally prompt 
him to the noblest deeds, it will more commonly lead him to 
gratify his own desires at the expense of other men. But after 
their gratification, when past and weaker impressions are judged 
by the ever-enduring social instinct, and by his deep regard 
for the good opinion of his fellows, retribution will surely come. 
He will then feel remorse, repentance, regret, or shame; this 
latter feeling, however, relates almost exclusively to the judg- 
ment of others. He will consequently resolve more or less firmly 
to act differently for the future; and this is conscience; for 
conscience looks backwards, and serves as a guide for the future. 

The nature and strength of the feelings which we call regret, 
shame, repentance or remorse, depend apparently not only on 
the strength of the violated instinct, but partly on the strength 
of the temptation, and often still more on the judgment of our 
fellows. How far each man values the appreciation of others, 
depends on the strength of his innate or acquired feeling of 
sympathy; and on his own capacity for reasoning out the re- 
mote consequences of his acts. Another element is most im- 



MORAL SENSE. Ill 

portant, although not necessary, the reverence or fear of the 
Gods, or Spirits believed in by each man: and this applies es- 
pecially in cases of remorse. Several critics have objected that 
though some slight regret or repentance may be explained by 
the view advocated in this chapter, it is impossible thus to ac- 
count for the soul-shaking feeling of remorse. But I can see 
little force in this objection. My critics do not define what 
they mean by remorse, and I can find no definition implying 
more than an overwhelming sense of repentance. Remorse 
seems to bear the same relation to repentance, as rage does to 
anger, or agony to pain. It is far from strange that an instinct 
so strong and so generally admired, as maternal love, should, if 
disobeyed, lead to the deepest misery, as soon as the impression 
of the past cause of disobedience is weakened. Even when an 
action is opposed to no special instinct, merely to know that our 
friends and equals despise us for it is enough to cause great 
misery. Who can doubt that the refusal to fight a duel through 
fear has caused many men an agony of shame? Many a Hindoo, 
it is said, has been stirred to the bottom of his soul by having 
partaken of unclean food. Here is another case of what must, I 
think, be called remorse. Dr. Landor acted as a magistrate in 
West Australia, and relates,-*^ that a native on his farm, after 
losing one of his wives from disease, came and said that "he was 
"going to a distant tribe to spear a woman, to satisfy his sense | 
"of duty to his wife. I told him that if he did so, I Y\rouldi 
"send him to prison for life. He remained about the farm for*^ 
"some months, but got exceedingly thin, and complained that 
"he could not rest or eat, that his wife's spirit was haunting 
"him, because he had not taken a life for hers. I was inex- 
"orable, and assured him that nothing should save him if he 
"did." Nevertheless the man disappeared for more than a year, 
and then returned in high condition; and his other wife told 
Dr. Landor that her husband had taken the life of a woman 
belonging to a distant tribe; but it was impossible to obtain 
legal evidence of the act. The breach of a rule held sacred by 
the tribe, will thus, as it seems, give rise to the deepest feelings, 
— and this quite apart from the social instincts, excepting in so 
far as the rule is grounded on the judgment of the community. 
How so many strange superstitions have arisen throughout the 
world we know not; nor can we tell how some real and great 
crimes, such as incest, have come to be held in an abhorrence 
(which is not however quite universal) by the lowest savages. It 
Is even doubtful whether in some tribes incest would be looked on 
with greater horror, than would the marriage of a man with a 
woman bearing the same name, though not a relation. "To 



'Insanity in Relation to Law;' Ontario, United States, 1871, p. 14. 



112 THE DESCENT OF MAN. 

"violate this law is a crime which the Australians hold in the 
"greatest abhorrence, in this agreeing exactly with certain 
"tribes of North America. When the question is put in either 
"district, is it worse to kill a girl of a foreign tribe, or to marry 
"a girl of one's own, an answer just opposite to ours would be 
"given without hesitation.""' We may, therefore, reject the be- 
lief, lately insisted on by some writers, that the abhorrence of 
incest is due to our possessing a special God-implanted con- 
science. On the whole it is intelligible, that a man urged by 
so powerful a sentiment as remorse, though arising as above 
explained, should be led to act in a manner, which he has been 
taught to believe serves as an expiation, such as delivering him- 
self up to justice. 

Man prompted by his conscience, will through long habit ac- 
quire such perfect self-command, that his desires and passions 
will at last yield instantly and without a struggle to his social 
sympathies and instincts, including his feeling for the judgment 
of his fellows. The still hungry, or the still revengeful man will 
not think of stealing food, or of wreaking his vengeance. It is 
possible, or as we shall hereafter see, even probable, that the 
habit of self-command may, like other habits, be inherited. Thus 
at last man comes to feel, through acquired and perhaps inherited 
habit, that it is best for him to obey his more persistent impulses. 
The imperious word ought seems merely to imply the conscious- 
ness of the existence of a rule of conduct, however it may have 
originated. Formerly it must have been often vehemently urged 
that an insulted gentleman ought to fight a duel. We even say 
that a pointer ought to point, and a retriever to retrieve game. If 
they fail to do so, they fail in their duty and act wrongly. 

If any desire or instinct leading to an action opposed to the 
good of others still appears, when recalled to mind, as strong 
as, or stronger than, the social instinct, a man will feel no keen 
regret at having followed it; but he will be conscious that if his 
conduct were known to his fellows, it would meet with their 
disapprobation; and few are so destitute of sympathy as not to 
feel discomfort when this is realized. If he has no such sym- 
pathy, and if his desires leading to bad actions are at the time 
strong, and when recalled are not over-mastered by the persistent 
social instincts, and the judgment of others, then he is essentially 
a bad man;^*^ and the sole restraining motive left is the fear of 
punishment, and the conviction that in the long run it would be 
best for his own selfish interests to regard the good of others 
rather than his own. 



20 E. B. Tylor in 'Contemporary Heview,' April, 1873, p. 707. 

30 Dr. Prosper Despine, in his 'Psychologie Naturelle,' 1868 (torn, i, p. 
243; torn. ii. p. 169) gives many curious cases of the worst criminals, 
who apparently have been entirely destitute of conscience. 



MORAL SENSE. 113 

It is obvious ttiat every one may with an easy conscience 
gratify his own desires, if they do not interfere with his social 
instincts, that is with the good of others; but in order to be 
quite free from self-reproach, or at least of anxiety, it is almost 
necessary for him to avoid the disapprobation, whether reason- 
able or not, of his fellow-men. Nor must he break through the 
fixed habits of his life, especially'' if these are supported by reason; 
for if he does, he will assuredly feel dissatisfaction. He must 
likewise avoid the reprobation of the one God or gods in whom, 
according to his knowledge or superstition, he may believe; but 
in this case the additional fear of divine punishment often super- 
venes. 

The strictly Social VlHues at first alone regarded. — The above 
view of the origin and nature of the moral sense, which tells us 
what we ought to do, and of the conscience which reproves us if 
we disobey it, accords well with what we see of the early and 
undeveloped condition of this faculty in mankind. The virtues 
which must be practiced, at least generally, by rude men, so 
that they may associate in a body, are those which are still 
recognized as the most important. But they are practiced almost 
exclusively in relation to the men of the same tribe; and their 
opposites are not regarded as crimes in relation to the men of 
other tribes. No tribe could hold together if murder, robbery, 
treachery, &c., were common; consequently such crimes within 
the limits of the same tribe "are branded with everlasting in- 
"famy;"^^ but excite no such sentiment beyond these limits. A 
North-American Indian is well pleased with himself, and is hon- 
ored by others, when he scalps a man of another tribe; and a 
Dj^ak cuts off the head of an unoffending person, and dries it as 
a trophy. The murder of infants has prevailed on the largest 
scale throughout the world,^ and has met with no reproach; but 
infanticide, especially of females, has been thought to be good 
for the tribe, or at least not injurious. Suicide during former 
times was not generally considered as a crime,^^ but rather, from 

31 See an able article in the 'North British Review,' 1S67, p. 395. See 
also Mr, W. Bagehot's articles on the Importance of Obedience and 
Coherence to Primitive Man, in the 'Fortnightly Review,' IS'oT, p. 529, 
and 1S68, p. 457, &c. 

^ The fullest account which I have met with is by Dr. Gerland, in 
his 'Ueber das Aussterben der Naturvolker,' 1868; but I shall have to 
recur to the subject of infanticide in a future chapter. 

^ See the very interesting discussion on Suicide in Lecky's 'History 
of European Morals,' vol. i. 1869, p. 223.. With respect to savages, Mr. 
"Winwood Reade informs me that the negroes of West Africa often 
commit smcide. It is well known how common it was amongst the 
miserable aborigines of South America, after the Spanish conquest. 



114 THE DESCENT OF MAN. 

the courage displayed, as an honorable act; and it is still prac- 
ticed by some semi-civilized and savage nations without reproach, 
for it does not obviously concern others of the tribe. It has been 
recorded that an Indian Thug conscientiously regretted that he 
had not robbed and strangled as many travelers as did his father 
before him. In a rude state of civilization the robbery of strang- 
ers is, indeed, generally considered as honorable. 

Slavery, although in some ways beneficial during ancient 
times,"* is a great crime; yet it was not so regarded until quite 
recently, even by the most civilized nations. And this was espe- 
cially the case, because the slaves belonged in general to a race 
different from that of their masters. As barbarians do not regard 
the opinion of their women, wives are commonly treated like 
slaves. Most savages are utterly indifferent to the sufferings of 
strangers, or even delight in witnessing them. It is well known 
that the women and children of the North-American Indians 
aided in torturing their enemies. Some savages take a horrid 
pleasure in cruelty to animals,^'^ and humanity is an unknown 
virtue. Nevertheless, besides the family affections, kindness is 
common, especially during sickness, between the members of 
the same tribe, and is sometimes extended beyond these limits. 
Mungo Park's touching account of the kindness of the negro 
women of the interior to him is well known. Many instances 
could be given of the noble fidelity of savages towards each other, 
but not to strangers; common experience justifies the maxim 
of the Spaniard, "Never, never trust an Indian." There cannot 
be fidelity without truth; and this fundamental virtue is not 
rare between the members of the same tribe: thus Mungo Park 
heard the negro women teaching their young children to love 
the truth. This, again, is one of the virtues which becomes so 
deeply rooted in the mind, that it is sometimes practiced by sav- 
ages, even at a high cost, towards strangers; but to lie to your 
enemy has rarely been thought a sin, as the history of modern 
diplomacy too plainly shows. As soon as a tribe has a recognized 
leader, disobedience becomes a crime, and even abject submission 
is looked at as a sacred virtue. 

As during rude times no man can be useful or faithful to his 
tribe without courage, this quality has universally been placed 
in the highest rank; and although in civilized countries a good 
yet timid man may be far more useful to the community than a 
brave one, we cannot help instinctively honoring the latter above 

For New Zealand, see the voyage of the "Novara," and for the Aleu- 
tian Islands, Muller, as quoted by Houzeau, 'Les Facultes Mentales,' 
&c., torn. ii. p. 136. 

34 See Mr. Bag-ehot, 'Physics and Politics,' 1872, p. 72. 

35 See, for instance, Mr. Hamilton's account of the Kaffirs, 'Anthro- 
pological Review,' 1870, p. xv. 



MORAL SENSE. 115 

a coward, however benevolent. Prudence, on the other hand, 
which does not concern the welfare of others, though a very use- 
ful virtue, has never been highly esteemed. As no man can 
practice the virtues necessary for the welfare of his tribe without 
self-sacrifice, self-command, and the power of endurance, these 
qualities have been at all times highly and most justly valued. 
The American savage voluntarily submits to the most horrid 
tortures without a groan, to prove and strengthen his fortitude 
and courage; and we cannot help admiring him, or even an In- 
dian Fakir, who, from a foolish religious motive, swings sus- 
pended by a hook buried in his flesh. 

The other so called self-regarding virtues, which do not ob- 
viously, though they may really, afiect the welfare of the tribe, 
have never been esteemed by savages, though now highly appre- 
ciated by civilized nations. The greatest intemperance is no 
reproach with savages. Utter licentiousness, and unnatural 
crimes, prevail to an astounding extent.^^ As soon, however, as 
marriage, whether polygamous, or monogamous, becomes com- 
mon, jealousy will lead to the inculcation of female virtue; and 
this, being honored, will tend to spread to the unmarried females. 
How slowly it spreads to the male sex, we see at the present da3\ 
Chastity eminently requires self-command; therefore it has been 
honored from a very early period in the moral history of civilized 
man. As a consequence of this, the senseless practice of celibacy 
has been ranked from a remote period as a virtue.^' The hatred 
of indecency, which appears to us so natural as to be thought in- 
nate, and which is so valuable an aid to chastity, is a modern 
virtue, appertaining exclusively, as Sir G. Staunton remarks,'^ to 
civilized life. This is shown by the ancient religious rites of 
various nations, by the drawings on the w^alls of Pompeii, and 
by the practices of many savages. 

We have now seen that actions are regarded by savages, and 
were probably so regarded by primaeval man, as good or bad, 
solely as they obviously affect the welfare of the tribe,— not that 
of the species, nor that of an individual member of the tribe. 
This conclusion agrees well with the belief that the so-called 
moral sense is aboriginally derived from the social instincts, for 
both relate at first exclusively to the community. The chief 
causes of the low morality of savages, as judged by our standard, 
are, firstly, the confinement of sympathy to the same tribe. Sec- 
ondly, powers of reasoning insufficient to recognize the bearing 
of many virtues, especially of the self-regarding virtues, on the 



38 Mr. M'Lennan has given ('Primitive Marriage,' 1865, p. 176) a good 
collection of facts on this head. 
3'^ Lecky, 'History of European Morals,' vol. i. 1869, p. 109. 
^ 'Embassy to China,' vol. ii. p. 348. 



116 THE DESCENT OF MAN. 

general welfare of the tribe. Savages, for instance, fail to trace 
the multiplied evils consequent on a want of temperance, chas- 
tity, &c. And, thirdly, weak power of self command; for this 
power has not heen strengthened through long-continued, per- 
haps inherited, habit, instruction and religion. 

I have entered into the above details on the immorality of 
savages,^^ because some authors have recently taken a high view 
of their moral nature, or have attributed most of their crimes to 
mistaken benevolence. *° These authors appear to rest their con- 
clusion on savages possessing those virtues which are serviceable, 
or even necessary, for the existence of the family and of the 
tribe, — qualities which they undoubtedly do possess, and often in 
a high degree. 



Concluding Bemarks. — It was assumed formerly by philoso- 
phers of the derivative*^ school of morals that the foundation of 
morality lay in a form of Selfishness; but more recently the 
"Greatest happiness principle" has been brought prominently 
forward. It is, however, more correct to speak of the latter prin- 
ciple as the standard, and not as the motive of conduct. Never- 
theless, all the authors whose works I have consulted, with a few 
exceptions,^ write as if there must be a distinct motive for every 
action, and that this must be associated with some pleasure or 
displeasure. But man seems often to act impulsively, that is 
from instinct or long habit, without any consciousness of pleasure, 

3» See on this subject copious evidence in Chap. vii. of Sir J. Lub- 
bock, 'Oi-igin of Civilization,' 1870. 

^° For instance, Lecky, 'Hist. European Morals,' vol. i. p. 124. 

^ This term is used in an able article in the 'Westminster Review,' 
Oct. 1869, p. 498. For the "Greatest happiness principle," see J. S. Mill, 
'Utilitarianism,' p. 17. 

^ Mill recognizes ('System of Logic,* vol. ii. p. 422) in the clearest 
manner, that actions may be performed through habit without the 
anticipation of pleasure. Mr. H. Sidgwick also in his Essay on Pleas- 
ure and Desire ('The Contemporary Review,' April 1872, p. 671), remarks: 
"To sum up, in contravention of the doctrine that our conscious ac- 
"tive impulses are always directed towards the production of agreeable 
"sensations in ourselves, I would maintain that we find everywhere in 
"consciousness extra-regarding impulse, directed towards something 
"that is not pleasure; that in many cases the impulse is so far incom- 
"patible with the self -regarding that the two do not easily co-exist in 
"the same moment of consciousness." A dim feeling that our impulses 
do not by any means always arise from any contemporaneous or an- 
ticipated pleasure, has, I cannot but think, been one chief cause of the 
acceptance of the intuitive theory of morality, and of the rejection of 
the utilitarian or "Greatest happiness" theory. With respect to the 
latter theory, the standard and the motive of conduct have no doubt 
often been confused, but they are really in some degree blended. 



MORAL SENSE. 11? 

in the same manner as does probably a bee or ant, when it 
blindly follows its instincts. Under circumstances of extreme 
peril, as during a fire, when a man endeavors to save a fellow- 
creature without a moment's hesitation, he can hardly feel pleas- 
ure; and still less has he time to reflect on the dissatisfaction 
which he might subsequently experience if he did not make the 
attempt. Should he afterwards reflect over his own conduct, he 
would feel that there lies within him an impulsive power widely 
different from a search after pleasure or happiness; and this 
seems to be the deeply planted social instinct. 

In the case of the lower animals it seems much more appro- 
priate to speak of their social instincts, as having been developed 
for the general good rather than for the general happiness of the 
species. The term, general good, may be deflned as the rearing 
of the greatest number of individuals in full vigor and health, 
with all their faculties perfect, under the conditions to which 
they are subjected. As the social instincts both of man and the 
lower animals have no doubt been developed by nearly the same 
steps, it would be advisable, if found practicable, to use the same 
definition in both cases, and to take as the standard of morality, 
the general good or welfare of the community, rather than the 
general happiness; but this definition would perhaps require some 
limitation on account of political ethics. 

When a man risks his life to save that of a fellow-creature, it 
seems also more correct to say that he acts for the general good, 
rather than for the general happiness of mankind. No doubt 
the welfare and the happiness of the individual usually coincide; 
and a contented, happy tribe will flourish better than one that 
is discontented and unhappy. We have seen that even at an 
early period in the history of man, the expressed wishes of the 
community will have naturally influenced to a large extent the 
conduct of each member; and as all wish for happiness, the 
"greatest happiness principle" will have become a most important 
secondary guide and object; the social instinct, however, together 
with sympathy (which leads to our regarding the approbation 
and disapprobation of others), having served as the primary im- 
pulse and guide. Thus the reproach is removed of laying the 
foundation of the noblest part of our nature in the base principle 
of selflshness; unless, indeed, the satisfaction which every animal 
feels, when it follows its proper instincts, and the dissatisfaction 
felt when prevented, be called selfish. 

The wishes and opinions of the members of the same com- 
munity, expressed at first orally, but later by writing also, either 
form the sole guides of our conduct, or greatly reinforce the 
social instincts; such opinions, however, have sometimes a ten- 
dency directly opposed to these instincts. This latter fact is 
well exemplified by the Law of Honor, that is, the law of the 

O 



118 THE DESCENT OF MAN. 

opinion of our equals, and not of all our countrymen. The breach 
of this law, even when the breach is known to be strictly ac- 
cordant with true morality, has caused many a man more agony 
than a real crime. We recognize the same influence in the burn- 
ing sense of shame which most of us have felt, even after the 
interval of years, when calling to mind some accidental breach 
of a trifling, though fixed, rule of etiquette. The judgment of 
the community will generally be guided by some rude experience 
of what is best in the long run for all the members; but this 
judgment will not rarely err from ignorance and weak powers of 
reasoning. Hence the strangest customs and superstitions, in 
complete opposition to the true welfare and happiness of man- 
kind, have become all-powerful throughout the world. We see 
this in the horror felt by a Hindoo who breaks his caste, and 
in many other such cases. It would be difficult to distinguish 
between the remorse felt by a Hindoo who has yielded to the 
temptation of eating unclean food, from that felt after commit- 
ting a theft; but the former would probably be the more severe. 

How so many absurd rules of conduct, as well as so many absurd 
religious beliefs, have originated, we do not know; nor how 
it is that they have become, in all quarters of the world, so 
deeply impressed on the mind of men; but it is worthy of re- 
mark that a belief constantly inculcated during the early years of 
life, whilst the brain is impressible, appears to acquire almost 
the nature of an instinct; and the very essence of an instinct is 
that it is followed independently of reason. Neither can we say 
why certain admirable virtues, such as the love of truth, are 
much more highly appreciated by some savage tribes than by 
others;*^ nor, again, why similar differences prevail even amongst 
highly civilized nations. Knowing how firmly fixed many strange 
customs and superstitions have become, we need feel no surprise 
that the self-regarding virtues, supported as they are by reason, 
should now appear to us so natural as to be thought innate, al- 
though they were not valued by man in his early condition. 

Notwithstanding many sources of doubt, man can generally 
and readily distinguish between the higher and lower moral 
rules. The higher are founded on the social instincts, and relate 
to the welfare of others. They are supported by the approbation 
of our fellow-men and by reason. The lower rules, though some 
of them, when implying self-sacrifice hardly deserve to be called 
lower, relate chiefly to self, and arise from public opinion, ma- 
tured by experience and cultivation; for they are not practiced 
by rude tribes. 

*3 Good instances are g-iven by Mr. Wallace in 'Scientific Opinion,* 
Sept. 15, 1869; and more fully in his 'Contributions to the Theory of 
Natural Selection,' 1870, p. 353. 



MORAL SENSE. 119 

As man advances in civilization, and small tribes are united 
into larger communities, the simplest reason would tell each 
individual that he ought to extend his social instincts and sym- 
pathies to all the members of the same nation, though personally 
unknown to him. This point being once reached, there is only an 
artificial barrier to prevent his sympathies extending to the men 
of all nations and races. If, indeed, such men are separated from 
tim by great differences in appearance or habits, experience un- 
fortunately shows us how long it is, before we look at them as 
our fellow-creatures. Sympathy beyond the confines of man, that 
is, humanity to the lower animals, seems to be one of the latest 
moral acquisitions. It is apparently unfelt by savages, except 
towards their pets. How little the old Romans knew of it is 
shown by their abhorrent gladiatorial exhibitions. The very idea 
of humanity, as far as I could observe, was new to most of the 
Gauchos of the Pampas. This virtue, one of the noblest with 
which man is endowed, seems to arise incidentally from our sym- 
pathies becoming more tender and more widely diffused, until 
they are extended to all sentient beings. As soon as this virtue 
is honored and practiced by some few men, it spreads through 
instruction and example to the young, and eventually becomes 
incorporated in public opinion. 

The highest possible stage in moral culture is when we recog- 
nize that we ought to control our thoughts, and "not even in 
"inmost thought to think again the sins that made the past so 
"pleasant to us."^* Whatever makes any bad action familiar to 
the mind, renders its performance by so much the easier. As 
Marcus Aurelius long ago said, "Such as are thy habitual 
"thoughts, such also will be the character of thy mind; for the 
"soul is dyed by the thoughts."*^ 

Our great philosopher, Herbert Spencer, has recently explained 
his views on the moral sense. He says,**' "I believe that the 
"experiences of utility organized and consolidated through all 
"past generations of the human race, h^ave been producing cor- 
"responding modifications, which, by continued transmission and 
"accumulation, have become in us certain faculties of moral 
"intuition — certain emotions responding to right and wrong con- 
"ducfc, which have no apparent basis in the individual experiences 
"of utility." There is not the least inherent improbability, as it 
seems to me, in virtuous tendencies being more or less strongly 
inherited; for, not to mention the various dispositions and habits 
transmitted by many of our domestic animals to their offspring, 

** Tennyson, 'Idylls of the King,' p. 244. 

45 'The Thoughts of the Emperor M. Aurelius Antoninus,' Eng. trans- 
lat., 2nd edit., 1869, p. 112. Marcus Aurelius was born A. D. 121. 
*« Letter to Mr. Mill in Bain's 'Mental and Moral Science,' 18o8, p. 722. 



120 THE DESCENT OP MAN. 

I have heard of authentic cases in which a desire to steal and 
a tendency to lie appeared to run in families of the upper ranks; 
and as stealing is a rare crime in the wealthy classes, we can 
hardly account by accidental coincidence for the tendency occur- 
ring in two or three members of the same family. If bad ten- 
dencies are transmitted, it is probable that good ones are like- 
wise transmitted. That the state of the body by affecting the 
brain, has great influence on the moral tendencies is known to 
most of those who have suffered from chronic derangements of 
the digestion or liver. The same fact is likewise shown by the 
"perversion or destruction of the moral sense being often one of 
^'the earliest symptoms of mental derangement;"*^ and insanity 
is notoriously often inherited. Except through the principle of 
the transmission of moral tendencies, we cannot understand the 
differences believed to exist in this respect between the various 
races of mankind. 

Even the partial transmission of virtuous tendencies would 
be an immense assistance to the primary impulse derived directly 
and indirectly from the social instincts. Admitting for a moment 
that virtuous tendencies are inherited, it appears probable, at 
least in such cases as chastity, temperance, humanity to animals, 
&c., that they become first impressed on the mental organization 
through habit, instruction and example, continuied during sev- 
eral generations in the same family, and in a quite subordinate 
degree, or not at all, by the individuals possessing such virtues 
having succeeded best in the struggle for life. My chief source 
of doubt with respect to any such inheritance, is that senseless 
customs, superstitions, and tastes, such as the horror of a Hindoo 
for unclean food, ought on the same principle to be transmitted. 
I have not met with any evidence in support of the transmission 
of superstitious customs or senseless habits, although in itself it 
is perhaps not less probable than that animals should acquire 
inherited tastes for certain kinds of food or fear of certain foes. 

Finally the social instincts, which no doubt were acquired by 
man as by the lower animals for the good of the community, 
will from the first have given to him some wish to aid his 
fellows, some feeling of sympathy, and have compelled him to 
regard their approbation and disapprobation. Such impulses 
! will have served him at a very early period as a rude rule of 
\ right and wrong. But as man gradually advanced in intellectual 
power, and was enabled to trace the more remote consequences 
of his actions; as he acquired sufiicient knowledge to reject 
baneful customs and superstitions; as he regarded more and 
more, not only the welfare, but the happiness of his fellow-men; 



*7 Maudsley, 'Body and Mind,' 1870, p. 60. 



SUMMARY. 121 -^ 

as from habit, following on beneficial experience, instruction 1 
and example, his sympathies became more tender and widely | 
diffused, extending to men of all races, to the imbecile, maimed, | 
and other useless members of society, and finally to the lower \ 
animals, — so would the standard of his morality rise higher and ] 
higher. And it is admitted by moralists of the derivative school 
and by some intuitionists, that the standard of morality has ; 
risen since an early period in the history of man.*^ 

As a struggle may sometimes be seen going on between the 
various instincts of the lower animals, it is not surprising that 
there should be a struggle in man between his social instincts, 
with their derived virtues, and his lower, though momentarily 
stronger impulses or desires. This, as Mr. Galton *^ has remarked, 
is all the less surprising, as man has emerged from a state of 
barbarism within a comparatively recent period. After having 
yielded to some temptation we feel a sense of dissatisfaction, 
shame, repentance, or remorse, analogous to the feelings caused 
by other powerful instincts or desires, when left unsatisfied or 
baulked. We compare the weakened impression of a past tempta- 
tion with the ever present social instincts, or with habits, gained 
in early youth and strengthened during our whole lives, until 
they have become almost as strong as instincts. If with the 
temptation still before us we do not yield, it is because either 
the social instinct or some custom is at the moment predominant, 
or because we have learnt that it will appear to us hereafter the 
stronger, when compared with the weakened impression of the , 
temptation, and we realize that its violation would cause us suf- i 
fering. Looking to future generations, there is no cause to fear J 
that the social instincts will grow weaker, and we may expect that "I 



virtuous habits will grow stronger, becoming perhaps fixed by | 
inheritance. In this case the struggle between our higher and f 
lower impulses will be less severe, and virtue will be triumphant. 



Summary of the last two Clia'pters. — There can be no doubt that 
the difference between the mind of the lowest man and that of 
the highest animal is immense. An anthropomorphous ape, if 
he could take a dispassionate view of his own case, would admit 
that though he could form an artful plan to plunder a garden — 
though he could use stones for fighting or for breaking open 

*8A writer in the 'North British Review' (July, 1869, p. 531), well 
capable of forming a sound judgment, expresses himself strongly in 
favor of this conclusion. Mr. Lecky ('Hist, of Morals,' vol. i. p. 143) 
seems to a certain extent to coincide therein. 

*® See his remarkable work on 'Hereditary Genius,' 1869, p. 349. The 
Duke of Argyll ('Primeval Man,' 1869, p. 188) has some good remarks on 
the contest in man's nature between right and wrong. 



122 THE DESCENT OF MAK. 

nuts, yet that the thought of fashioning a stone into a tool was 
quite beyond his scope. Still less, as he would admit, could he 
follow out a train of metaphysical reasoning, or solve a mathe- 
matical problem, or reflect on God, or admire a grand natural 
scene. Some apes, however, would probably declare that they 
could and did admire the beauty of the colored skin and fur of 
their partners in marriage. They would admit, that though they 
could make other apes understand by cries some of their per- 
ceptions and simpler wants, the notion of expressing definite ideas 
by definite sounds had never crossed their minds. They might 
insist that they were ready to aid their fellow-apes of the same 
troop in many ways, to risk their lives for them, and to take 
charge of their orphans; but they would be forced to acknowl- 
edge that disinterested love for all living creatures, the most 
noble attribute of man, was quite beyond their comprehension. 

Nevertheless the difference in mind between man and the 
higher animals, great as it is, certainly is one of degree and not 
of kind. We have seen that the senses and intuitions, the 
various emotions and faculties, such as love, memory, attention, 
curiosity, imitation, reason, &c., of which man boasts, may be 
found in an incipient, or even sometimes in a well-developed 
condition, in the lower animals. They are also capable of some 
inherited improvement, as we see in the domestic dog compared 
with the wolf or jackal. If it could be proved that certain high 
mental powers, such as the formation of general concepts, self- 
consciousness, &c., were absolutely peculiar to man, which seems 
extremely doubtful, it is not improbable that these qualities are 
merely the incidental results of other highly-advanced intellec- 
tual faculties; and these again mainly the result of the continued 
use of a perfect language. At what age does the new-born in- 
fant possess the power of abstraction, or become self-conscious, 
land reflect on its own existence? We cannot answer; nor can 
I we answer in regard to the ascending organic scale. The half- 
';• art, half-instinct of language still bears the stamp of its gradual 
evolution. The ennobling belief in God is not universal with 
man; and the belief in spiritual agencies naturally follows from 
other mental powers. The moral sense perhaps affords the best 
and highest distinction between man and the lower animals; but 
I need say nothing on this head, as I have so lately endeavored 
to show that the social instincts, — the prime principle of man's 
moral constitution^^ — with the aid of active intellectual powers 
and the effects of habit, naturally lead to the golden rule, "As ye 
"would that men should do to you, do ye to them likewise;" and 
this lies at the foundation of morality. 

50 'The Thoughts of Marcus Aurelius,' &c., p. 138. 



SUMMARY. 123 

In the next chapter I shall make some few remarks on the 
probable steps and means by which the several mental and moral 
faculties of man have been gradually evolved. That such evolu- 
tion is at least possible, ought not to be denied, for we daily see 
these faculties developing in every infant; and we may trace a 
perfect gradation from the mind of an utter idiot, lower than 
that of an animal low in the scale, to the mind of a Newton. 



12i THE DESCENT OF MAN. 



CHAPTER V. 

ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL 
FACULTIES DURING PRIMEVAL AND CIVILIZED TIMES. 

Advancement of the intellectual powers through natural selection — 
Importance of imitation— Social and moral faculties— Their devel- 
opment within the limits of the same tribe — Natural selection as 
affecting civilized nations— Evidence that civilized nations were 
once barbarous. 

The subjects to be discussed in this chapter are of the highest 
interest, but are treated by me in an imperfect and fragmentary 
manner. Mr. Wallace, in an admirable paper before referred to,* 
argues that man, after he had partially acquired those intellec- 
tual and moral faculties which distinguish him from the lower 
animals, would have been but little liable to bodily modifica- 
tions through natural selection or any other means. For man is 
enabled through his mental faculties "to keep with an unchanged 
"body in harmony with the changing universe." He has great 
power of adapting his habits to new conditions of life. He in- 
vents weapons, tools, and various stratagems to procure food and 
to defend himself. When he migrates into a colder climate he 
uses clothes, builds sheds, and makes fires; and by the aid of 
fire cooks food otherwise indigestible. He aids his fellow-men in 
many ways, and anticipates future events. Even at a remote 
period he practiced some division of labor. 

The lower animals, on the other hand, must have their bodily 
structure modified in order to survive under greatly changed 
conditions. They must be rendered stronger, or acquire more 
effective teeth or claws, for defense against new enemies; or 
they must be reduced in size, so as to escape detection and dan- 
ger. When they migrate into a colder climate, they must become 
clothed with thicker fur, or have their constitutions altered. If 
they fail to be thus modified, they will cease to exist. 

The case, however, is widely different, as Mr. Wallace has with 
justice insisted, in relation to the intellectual and moral faculties 



1 'Anthropological Review,' May, 1864, p. clviii. 



INTELLECTUAL FACULTIES. 125 

of man. These faculties are variable; and we have every reason 
to believe that the variations tend to be inherited. Therefore, if 
they were formerly of high importance to primeval man and to 
his ape-like progenitors, they would have been perfected or ad- 
vanced through natural selection. Of the high importance of the 
intellectual faculties there can be no doubt, for man mainly owes 
to them his predominant position in the world. We can see, 
that in the rudest state of society, the individuals who were the 
most sagacious, who invented and used the best weapons or 
traps, and who were best able to defend themselves, would rear 
the greatest number of offspring. The tribes, which included 
the largest number of men thus endowed, would increase in 
number and supplant other tribes. Numbers depend primarily 
on the means of subsistence, and this depends partly on the phys- 
ical nature of the country, but in a much higher degree on the 
arts which are there practiced. As a tribe increases and is vic- 
torious, it is often still further increased by the absorption of 
other tribes.^ The stature and strength of the men of a tribe 
are likewise of some importance for its success, and these depend 
in part on the nature and amount of the food which can be 
obtained. In Europe the men of the Bronze period were sup- 
planted by a race more powerful, and, judging from their sword- 
handles, with larger han<ls;^ but their success was probably still 
more due to their superiority in the arts. 

All that we know about savages, or may infer from their tra- 
ditions and from old monuments, the history of which is quite 
forgotten by the present inhabitants, show that from the remotest 
times successful tribes have supplanted other tribes. Relics of 
extinct or forgotten tribes have been discovered throughout the 
civilized regions of the earth, on the wild plains of America, and 
on the isolated islands in the Pacific Ocean. At the present day 
civilized nations are everywhere supplanting barbarous nations, 
excepting where the climate opposes a deadly barrier; and they 
succeed mainly, though not exclusively, through their arts, which 
are the products of the intellect. |^It is, therefore, highly probable 
that with mankind the intellecthal faculties have been mainly 
and gradually perfected through natural selection; and this con- 
clusion is sufficient for our purpose. Undoubtedly it would be 
interesting to trace the development of each separate faculty 
from the state in which it exists in the lower animals to that in 
which it exists in man; but neither my ability nor knowledge 
permits the attempt. 

2 After a time the members or tribes which are absorbed into another 
tribe assume, as Sir Henry Maine remarks ('Ancient Law,' 1831, p 7^), 
that they are the co-descendants of the same ancestors. 

» Morlot, 'Soc. Vaud. Sc. Nat.' 1860, p. 294. 



126 THE DESCENT OF MAN. 

It deserves notice that, as soon as the progenitors of man be- 
came social (and this probably occurred at a very early period), 
the principle of imitation, and reason, and experience would have 
increased, and much modified the, intellectual powers in a way, 
of which we see only traces in the lower animals. Apes are 
much given to imitation, as are the lowest savages; and the 
simple fact previously referred to, that after a time no animal 
can be caught in the same place by the same sort of trap, shows 
that animals learn by experience, and imitate the caution of 
others. Now, if some one man in a tribe, more sagacious than 
the others, invented a new snare or weapon, or other means of 
attack or defense, the plainest self-interest, without the assistance 
of much reasoning power, would prompt the other members to 
imitate him; and all would thus profit. The habitual practice 
of each new art must likewise in some slight degree strengthen 
the intellect. If the new invention were an important one, the 
tribe would increase in number, spread, and supplant other tribes. 
In a tribe thus rendered more numerous there would always be 
a rather greater chance of the birth of other superior and in- 
ventive members. If such men left children to inherit their men- 
tal superiority, the chance of the birth of still more ingenious 
members would be somewhat better, and in a very small tribe 
decidedly better. Even if theyi left no children, the tribe would 
still include their blood-relations; and it has been ascertained 
by agriculturists* that by preserving and breeding from the 
family of an animal, which when slaughtered was found to be 
valuable, the desired character has been obtained. 

Turning now to the social and moral faculties. In order that 
primeval men, or the ape-like progenitors of man, should become 
social, they must have acquired the same instinctive feelings, 
which impel other animals to live in a body; and they no doubt 
exhibited the same general disposition. They would have felt 
uneasy when separated from their comrades, for whom they 
would have felt some degree of love; they v/ould have v/arned 
each other of danger, and have given mutual aid in attack or 
defense. All this implies some degree of sympathy, fidelity, and 
courage. Such social qualities, the paramount importance of 
which to the lower animals is disputed by no one, were no doubt 
acquired by the progenitors of man in a similar manner, namely, 
through natural selection, aided by inherited habit. When two 
' tribes of primeval man, living in the same country, came into 
, competition, if (other circumstances being equal) the one tribe 
f included a great number of courageous, sympathetic and faithful 

* I have given instances in my 'Variation of Animals under Domesti- 
cation,' vol. ii. p. 196. 



MORAL FACULTIES. 127 

members, who were always ready to warn each other of danger, 
to aid and defend each other, this tribe would succeed better and 
conquer the other. Let it be borne in mind how all-important 
in the never-ceasing wars of savages, fidelity and courage must 
be. The advantage which disciplined soldiers have over undis- 
ciplined hordes follows chiefly from the confidence which each 
man feels in his comrades. Obedience, as Mr. Bagehot has well 
shown,^ is of the highest value, for any form of government is 
better than none. Selfish and contentious people will not cohere, 
and without coherence nothing can be effected. A tribe rich in 
the above qualities would spread and be victorious over other 
tribes: but in the course of time it would, judging from all past 
history, be in its turn overcome by some other tribe still more 
highly endowed. Thus the social and moral qualities would tend 
slowly to advance and be diffused throughout the world. 

But it may be asked, how within the limits of the same tribe 
did a large number of members first become endowed with these 
social and moral qualities, and how was the standard of ex- 
cellence raised? It is extremely doubtful whether the offspring 
of the more sympathetic and benevolent parents, or of those 
who were the most faithful to their comrades, would be reared 
in greater numbers than the children of selfish and treacherous 
parents belonging to the same tribe. He who was ready to sacri- 
fice his life, as many a savage has been, rather than betray his 
comrades, would often leave no offspring to inherit his noble 
nature. The bravest men, who were always willing to come to 
the front in war, and who freely risked their lives for others, 
would on an average perish in larger numbers than other men. 
Therefore it hardly seems probable, that the number of men 
gifted with such virtues, or that the standard of their excellence, 
could be increased through natural selection, that is, by the 
survival of the fittest; for we are not here speaking of one tribe 
being victorious over another. 

Although the circumstances, leading to an increase in the num- 
ber of those thus endowed within the same tribe, are too complex 
to be clearly followed out, we can trace some of the probable 
steps. In the first place, as the reasoning powers and foresight 
of the members became improved, each man would soon learn 
that if he aided his fellow-men, he would commonly receive aid in 
return. From this low motive he might acquire the habit of 
aiding his fellows; and the habit of performing benevolent ac- 
tions certainly strengthens the feeling of sympathy which gives 

* See a remarkable series of articles on 'Physics and Politics' in the 
•Fortnightly Review,' Nov. 1867; April. 1, 1868; July 1, 1869, sine© sep- 
arately published. 



128 THE DESCENT OF MAN. 

the first impulse to benevolent actions. Habits, moreover, fol- 
lowed during many generations probably tend to be inherited. 

But another and much more powerful stimulus to the develop- 
ment of the social virtues, is afforded by the praise and the blame 
of our fellow-men. To the instinct of sympathy, as we have al- 
ready seen, it is primarily due, that we habitually bestow both 
praise and blame on others, whilst we love the former and dread 
the latter when applied to ourselves; and this instinct no doubt 
was originally acquired, like all the other social instincts, through 
natural selection. At how early a period the progenitors of man 
in the course of their development, became capable of feeling and 
being impelled by, the praise or blame of their fellow-creatures, 
we cannot of course say. But it appears that even dogs appre- 
ciate encouragement, praise, and blame. The rudest savages feel 
the sentiment of glory, as they clearly show by preserving the 
trophies of their prowess, by their habit of excessive boasting, 
and even by the extreme care v/hich they take of their personal 
appearance and decorations; for unless they regarded the opinion 
of their comrades, such habits would be senseless. 

They certainly feel shame at the breach of some of their lesser 
rules, and apparently remorse, as shown by the case of the Aus- 
tralian who grew thin and could not rest from having delayed 
to murder some other woman, so as to propitiate his dead wife's 
spirit. Though I have not met with any other recorded case, 
it is scarcely credible that a savage, who will sacrifice his life 
rather than betray his tribe, or one who will deliver himself up 
as a prisoner rather than break his parole,^ would not feel re- 
morse in his inmost soul, if he had failed in a duty, which he 
held sacred. 

f~ We may therefore conclude that primeval man, at a very remote 
period, was influenced by the praise and blame of his fellows. 
It is obvious, that the members of the same tribe would approve 
of conduct which appeared to them to be for the general good, 
and would reprobate that which appeared evil. To do good unto 
others — to do unto others as ye would they should do unto you — 
is the foundation-stone of morality. It is, therefore, hardly pos- 
sible to exaggerate the importance during rude times of the love 
of praise and the dread of blame. A man who was not impelled 
by any deep, instinctive feeling, to sacrifice his life for the good 
of others, yet was roused to such actions by a sense of glory, 
would by his example excite the same wish for glory in other 
men, and would strengthen by exercise the noble feeling of ad- 
miration. He might thus do far more good to his tribe than 

• Mr. Wallace gives cases in his 'Contributions to the Theory of 
Natural Selection,' 1870, p. 364. 



MORAL FACULTIES. 129 

by Degetting offspring with a tendency to inherit his own high 
character. 

With increased experience and reason, man perceives the more ) 
remote consequences of his actions, and the self-regarding vir- / 
tues, such as temperance, chastity, &c., which during early times/ 
are, as we have before seen, utterly disregarded, come to be 
highly esteemed or even held sacred. I need not, however, repeat 
what I have said on this head in the fourth chapter. Ultimately 
our moral sense or conscience becomes a highly complex senti- 
ment — originating in the social instincts, largely guided by the 
approbation of our fellow-men, ruled by reason, self-interest, and 
in later times by deep religious feelings, and confirmed by instruc- 
tion and habit. 

It must not be forgotten that although a high standard of 
morality gives but a slight or no advantage to each individual 
man and his children over the other men of the same tribe, yet 
that an increase in the number of well-endowed men and an 
advancement in the standard of morality will certainly give an 
immense advantage to one tribe over another. A tribe including - 
many members who, from possessing in a high degree the spirit 
of patriotism, fidelity, obedience, courage, and sympathy, were 
always ready to aid one another, and to sacrifice themselves for 
the common good, would be victorious over most other tribes; 
and this would be natural selection. At all times throughout 
the world tribes have supplanted other tribes; and as morality 
is one important element in their success, the standard of 
morality and the number of well-endowed men will thus every- 
where tend to rise and increase. .^ 

It is however, very difficult to form any judgment why one 
particular tribe and not another has been successful and has 
risen in the scale of civilization. Many savages are in the same 
condition as when first discovered several centuries ago. As Mr. 
Bagehot has remarked, we are apt to look at progress as normal 
in human society; but history refutes this. The ancients did 
not even entertain the idea, nor do the Oriental nations at the 
present day. According to another high authority. Sir Henry 
Maine,^ "the greatest part of mankind has never shown a particle 
"of desire that its civil institutions should be improved." Progress 
seems to depend on many concurrent favorable conditions, far 
too complex to be followed out. But it has often been remarked, 
that a cool climate, from leading to industry and to the various 
arts, has been highly favorable thereto. The Esquimaux, pressed 
by hard necessity, have succeeded in many ingenious inventions, 
but their climate has been too severe for continued progress. 

' 'Ancient Law,' 1861, p. 22. For Mr. Bagehot's remarks, 'Fortnightly 
Review,' April 1, 1368, p. 452. 
10 



130 THE DESCENT OF MAN. 

Nomadic habits, whether over wide plains, or through the dense 
forests of the tropics, or along the shores of the sea, have in 
every case been highly detrimental. Whilst observing the bar- 
barous inhabitants of Tierra del Puego, it struck me that the pos- 
session of some property, a fixed abode, and the union of many 
families under a chief, were the indispensable requisites for civil- 
ization. Such habits almost necessitate the cultivation of the 
ground; and the first steps in cultivation would probably result, 
as I have elsewhere shown,^ from some such accident as the seeds 
of a fruit-tree falling on a heap of refuse, and producing an un- 
usually fine variety. The problem, however, of the first advance 
of savages towards civilization is at present much too difficult to 
be solved. 

Natural Selection as affecting Civilized Nations. — I have hither- 
to only considered the advancement of man from a semi-human 
condition to that of the modern savage. But some remarks on 
the action of natural selection on civilized nations may be worth 
adding. This subject has been ably discussed by Mr. W. R. 
Greg,^ and previously by Mr. Wallace and Mr. Galton." Most 
of my remarks are taken from these three authors. With sav- 
ages, the weak in body or mind are soon eliminated; and those 
that survive commonly exhibit a vigorous state of health. We 
Civilized men, on the other hand, do our utmost to check the 
process of elimination; we build asylums for the imbecile, the 
maimed, and the sick; we institute poor-laws; and our medical 
men exert their utmost skill to save the life of every one to the 
last moment. There is reason to believe that vaccination has 
preserved thousands, who from a weak constitution would for- 
merly have succumbed to small-pox. Thus the weak members of 
civilized societies propagate their kind. No one who has attended 
to the breeding of domestic animals will doubt that this must 
be highly injurious to the race of man. It is surprising how soon 
a want of care, or care wrongly directed, leads to the degenera- 



8 'The Variation of Animals and Plants under Domestication,' vol. i. 
p. 309. 

» 'Fraser's Mag-azine,' Sept. 1868, p. 353. This article seems to have 
struck many persons, and has given rise to two remarkable essays, 
and a rejoinder in the 'Spectator,' Oct. 3rd and 17th, 1868. It has also 
been discussed in the 'Q. Journal of Science,' 1869, p. 152, and by Mr. 
JLiawson Tait in the 'Dublin Q. Journal of Medical Science,' Feb. 1S69, 
and by Mr. E. Ray Lankester in his 'Comparative Longevity,' 1870, p. 
128. Similar views appeared previously in tHe 'Australasian,' July 13, 
1867. I have borrowed ideas from several of these writers. 

10 For Mr. Wallace, see 'Anthropolog. Review,' as before cited. Mr. 
Galton in 'MacmiUan's Magazine,' Aug. 1865. p; 318; also his great work, 
'Hereditary Genius,' 1870. 



CIVILIZED NATIONS. 131 

tlon of a domestic race; but excepting in the case of man him- 
self, hardly any one is so ignorant as to allow his worst animals 
to breed. 

The aid which we feel impelled to give to the helpless is mainly 
an incidental result of the instinct of sympathy, which was orig- 
inally acquired as part of the social instincts, but subsequently 
rendered, in the manner previously indicated, more tender and 
more widely diffused. Nor could we check our sympathy, even 
at the urging of hard reason, without deterioration in the noblest 
part of our nature. The surgeon may harden himself whilst per- 
forming an operation, for he knows that he is acting for the good 
of his patient; but if we were intentionally to neglect the weak and 
helpless, it could only be for a contingent benefit, with an over- 
whelming present evil. We must therefore bear the undoubtedly 
bad effects of the weak surviving and propagating their kind; but 
there appears to be at least one check in steady action, namely 
that the weaker and inferior members of society do not marry 
so freely as the sound; and this check might be indefinitely in- 
creased by the weak in body or mind refraining from marriage, 
though this is more to be hoped for than expected. 

In every country in which a large standing army is kept up, 
the finest young men are taken by the conscription or are en- 
listed. They are thus exposed to early death during war, are 
often tempted into vice, and are prevented from marrying during 
the prime of life. On the other hand the shorter and feebler men, 
with poor constitutions, are left at home, and consequently have 
a much better chance of marrying and propagating their kind." 

Man accumulates property and bequeaths it to his children, 
so that the children of the rich have an advantage over the poor 
in the race for success, independently of bodily or mental su- 
periority. On the other hand, the children of parents who are 
short-lived, and are therefore on an average deficient in health 
and vigor, come into their property sooner than other children, 
and will be likely to marry earlier, and leave a larger number of 
offspring to inherit their inferior constitutions. But the in- 
heritance of property by itself is very far from an evil; for with- 
out the accumulation of capital the arts could not progress; and 
it is chiefly through their power that the civilized races have 
extended, and are now everywhere extending their range, so as 
to take the place of the lower races. Nor does the moderate ac- 
cumulation of wealth interfere with the process of selection. 
When a poor man becomes moderately rich, his children enter 
trades or professions in which there is struggle enough, so that 



" Prof. H. Fick ('Einfluss der Naturwissenschaft auf das Recht,' 
June 1872,) has some good remarks on this head, and on other such 
points. 



132 f HE3 DESCENT OF MAN. 

the able in body and mind succeed best. The presence of a body 
of well-instructed men, who have not to labor for their daily 
bread, is important to a degree which cannot be over-estimated; 
as all high intellectual work is carried on by them, and on such 
work, material progress of all kinds mainly depends, not to 
mention other and higher advantages. No doubt wealth when 
very great tends to convert men into useless drones, but their 
number is never large; and some degree of elimination here 
occurs, for we daily see rich men, who happen to be fools or 
profligate, squandering away their wealth. 

Primogeniture with entailed estates is a more direct evil, 
though it may formerly have been a great advantage by the 
creation of a dominant class, and any government is better than 
none. Most eldest sons, though they may be weak in body or 
mind, marry, whilst the younger sons, however superior in these 
respects, do not so generally marry. Nor can worthless eldest sons 
with entailed estates squander their wealth. But here, as else- 
where, the relations of civilized life are so complex that some 
compensatory checks intervene. The men who are rich through 
primogeniture are able to select generation after generation the 
more beautiful and charming women; and these must generally 
be healthy in body and active in mind. The evil consequences, 
such as they may be, of the continued preservation of the same 
line of descent, without any selection, are checked by men of 
rank always wishing to increase their wealth and power; and 
this they effect by marrying heiresses. But the daughters of 
parents who have produced single children, are themselves, as 
Mr. Galton^' has shown, apt to be sterile; and thus noble families 
are continually cut off in the direct line, and their wealth flows 
into some side channel; but unfortunately this channel is not 
determined by superiority of any kind. 

Although civilization thus checks in many ways the action of 
natural selection, it apparently favors the better development 
of the body, by means of good food and the freedom from occa- 
sional hardships. This may be inferred from civilized men hav- 
ing been found, wherever compared, to be physically stronger 
than savages.'^^ They appear also to have equal powers of en- 
durance, as has been proved in many adventurous expeditions. 
Even the great luxury of the rich can be but little detrimental, 
for the expectation of life of our aristocracy, at all ages and of 
both sexes, is very little inferior to that of healthy English lives 
in the lower classes." 



12 'Hereditary Genius,' 1870, pp. 132-140. 

13 Quatrefages, 'Revue des Cours Scientifiques,' 1867-68, p. 659. 

1* See the fifth and sixth columns, compiled from good authorities, in 
the table given in Mr. E, E. Lankester's 'Comparative Longevity,' 1870, 

p. 115. 



CIVILIZED NATIONS. 133 

We will now look to the intellectual faculties. If in each grade 
of society the members were divided into two equal bodies, the 
one including the intellectually superior and the other the in- 
ferior, there can be little doubt that the former would succeed 
best in all occupations, and rear a greater number of children. 
Even in the lowest walks of life, skill and ability must be of 
some advantage; though in many occupations, owing to the great 
division of labor, a very small one. Hence in civilized nations 
there will be some tendency to an increase both in the number 
and in the standard of the intellectually able. But I do not wish 
to assert that this tendency may not be more than counterbal- 
anced in other ways as by the multiplication of the reckless and 
improvident; but even to such as these, ability must be some 
advantage. 

It has often been objected to views like the foregoing, that the 
most eminent men who have ever lived have left no offspring to 
inherit their great intellect. Mr. Galton says,^^ "I regret I am 
"unable to solve the simple question whether, and how far, men 
"and women who are prodigies of genius are infertile. I have, 
"however, shown that men of eminence are by no means so." 
Great lawgivers, the founders of beneficent religions, great philos- 
ophers and discoverers in science, aid the progress of mankind 
in a far higher degree by their works than by leaving a numerous 
progeny. In the case of corporeal structures, it is the selection of 
the slightly better-endowed and the elimination of the slightly 
less well-endowed individuals, and not the preservation of 
strongly-marked and rare anomalies, that leads to the advance- 
ment of a species.^*^ So it will be with the intellectual faculties, 
since the somewhat abler men in each grade of society succeed 
rather better than the less able, and consequently increase in 
number, if not otherwise prevented. When in any nation the 
standard of intellect and the number of intellectual men have 
increased, we may expect from the law of the deviation from 
an average, that prodigies of genius will, as shown by Mr. Galton, 
appear somewhat more frequently than before. 

In regard to the moral qualities, some elimination of the worst 
dispositions is always in progress even in the most civilized na- 
tions. Malefactors are executed, or imprisoned for long periods, 
so that they cannot freely transmit their bad qualities. Melan- 
cholic and insane persons are confined, or commit suicide. Violent 
and quarrelsome men often come to a bloody end. The restless 
who will not follow any steady occupation — and t^iis relic of 
barbarism is a great check to civilization^' — emigrate to newly- 

15 'Hereditary Genius,' 1870, p. 330. 

" 'Origin of Species' (fifth edition, 1869), p. 104. 

" 'Hereditar:-- Genius,' 1870, p. 347. 

10 



134 THE DESCENT OF MAN. 

settled countries, where they prove useful pioneers. Intemper- 
ance is so highly destructive, that the expectation of life of the 
intemperate, at the age of thirty for instance, is only 13.8 years; 
whilst for the rural laborers of England at the same age it is 
40.59 years.^^ Profligate women bear few children, and profligate 
men rarely marry; both suffer from disease. In the breeding of 
domestic animals, the elimination of those individuals, though 
few in number, which are in any marked manner inferior, is by 
no means an unimportant element towards success. This espe- 
cially holds good with injurious characters which tend to reap- 
pear through reversion, such as blackness in sheep; and with 
mankind some of the worst dispositions, which occasionally with- 
out any assignable cause make their appearance in families, may 
perhaps be reversions to a savage state, from which we are not 
removed by very many generations. This view seems indeed 
recognized in the common expression that such men are the black 
sheep of the family. 

With civilized nations, as far as an advanced standard of 
morality, and an increased number of fairly good men are con- 
cerned, natural selection apparently effects but little; though 
the fundamental social instincts were originally thus gained. 
But I have already said enough, whilst treating of the lower 
races, on the causes which lead to the advance of morality, name- 
ly, the approbation of our fellow-men — ^the strengthening of our 
sympathies by habit — example and imitation — reason — experience, 
and even self-interest — instruction during youth, and religious 
feelings. 

A most important obstacle in civilized countries to an increase 
in the number of men of a superior class has been strongly in- 
sisted on by Mr. Greg and Mr. Galton,^^ namely, the fact that the 
very poor and reckless, who are often degraded by vice, almost 
invariably marry early, whilst the careful and frugal, who are 
generally otherwise virtuous, marry late in life, so that they may 
be able to support themselves and their children in comfort. 
Those who marry early produce within a given period not only a 
greater number of generations, but, as shown by Dr. Duncan,^" 



1* E. Ray Lankester, 'Comparative Longevity,' 1870, p. 115. The table 
of the intemperate is from Nelson's 'Vital Statistics.' In regard to 
profligacy, see Dr. Farr, 'Influence of Marriage on Mortality/ 'Nat. 
Assoc, for the Promotion of Social Science,' 1858. 

i» 'Fraser's Magazine,' Sept. 1868, p. 353. 'Macmillan's Magazine,' Aug 
1865, p. 318. The Rev. F. W. Farrar ('Fraser's Mag.' Aug. 1870, p. 264), 
takes a different view. 

20 'On the Laws of the Fertility of Women,' in 'Transact. Royal 
Soc' Edinburgh, vol. xxiv. p. 287; now published separately under the 
title of 'Fecundity, Fertility, and Sterility,' 1871. See, also, Mr. Galtoiis- 
'Hereditary Genius,' pp. 352-357, fot observations to the above effect. 



CIVILIZED NATIONS. 135 

they produce many more children. The children, moreover, that 
are born by mothers during the prime of life are heavier and 
larger, and therefore probably more vigorous, than those born 
at other periods. Thus the reckless, degraded, and often vicious 
members of society, tend to increase at a quicker rate than the 
provident and geiuerally virtuous members. Or as Mr. Greg puts 
the case: "The careless, squalid, unaspiring Irishman multiplies 
"like rabbits: the frugal, foreseeing, self-respecting, ambitious 
"Scot, stern in his morality, spiritual in his faith, sagacious and 
"disciplined in his intelligence, passes his best years in struggle 
"and in celibacy, marries late, and leaves few behind him. Given 
"a land originally peopled by a thousand Saxons and a thousand 
"Celts — and in a dozen generations five-sixths of the population 
"would be Celts, but five-sixths of the property, of the power, of 
"the intellect, would belong to the one-sixth of Saxons that re- 
"mained. In the eternal 'struggle for existence,' it would be the 
"inferior and less favored race that had prevailed — and prevailed 
"by virtue not of its good qualities but of its faults." 

There are, however, some checks to this downward tendency. 
We have seen that the intemperate suffer from a high rate of 
mortality, and the extremely profligate leave few offspring. The 
poorest classes crowd into towns, and it has been proved by Dr. 
Stark from the statistics of ten years in Scotland,-^ that at all 
ages the death-rate is higher in towns than in rural districts, 
"and during the first five years of life the town death-rate is 
"almost exactly double that of the rural districts." As these re- 
turns include both the rich and the poor, no doubt more than 
twice the number of births would be requisite to keep up the 
number of the very poor inhabitants in the towns, relatively to 
those in the country. With women, marriage at too early an 
age is highly injurious; for it has been found in France that, 
"twice as many wives under twenty die in the year, as died out 
"of the same number of the unmarried." The mortality, also, 
of husbands under twenty is "excessively high,"^^ but what the 
cause of this may be, seems doubtful. Lastly, if the men who 
prudently delay marrying until they can bring up their families 
in comfort, were to select, as they often do, women in the prime 
of life, the rate of increase in the better class would be only 
slightly lessened. 

It was established from an enormous body of statistics, taken 
during 1853, that the unmarried men throughout France, between 

21 'Tenth Annual Report of Births, Deaths, &c., in Scotland,' 1867, p. 
xxix. 

22 These quotations are taken from our highest authority on such 
questions, namely. Dr. Farr, in his paper 'On the Influence of Mar- 
riage on the Mortality of the French People,' read before the Nat. 
Assoc, for the Promotion of Social Science 1858. 



136 THE DESCENT OP MAN. 

the ages of twenty and eighty, die in a much larger proportion 
than the married: for instance, out of every 1000 unmarried men, 
between the ages of twenty and thirty, 11.3 annually died, whilst 
of the married only 6.5 died.^^ A similar law was proved to hold 
good, during the years 1863 and 1864, with the entire population 
above the age of twenty in Scotland: for instance, out of every 
1000 unmarried men, between the ages of twenty and thirty, 14.97 
annually died, whilst of the married only 7.24 died, that is less 
than half.-* Dr. Stark remarks on this, "Bachelorhood is more 
"destructive to life than the most unwholesome trades, or than 
"residence in an unwholesome house or district where there has 
"never been the most distant attempt at sanitary improvement." 
He considers that the lessened mortality is the direct result of 
"marriage, and the more regular domestic habits which attend 
"that state." He admits, however, that the intemperate, profli- 
gate, and criminal classes, whose duration of life is low, do not 
commonly marry; and it must likewise be admitted that men 
with a weak constitution, ill health, or any great infirmity in body 
or mind, will often not wish to marry, or will be rejected. Dr. 
Stark seems to have come to the conclusion that marriage in itself 
is a main cause of prolonged life, from finding that aged married 
men still have a considerable advantage in this respect over the 
unmarried of the same advanced age; but every one must have 
known instances of men, who with weak health during youth 
did not marry, and yet have survived to old age, though remaining 
weak, and therefore always with a lessened chance of life or of 
marrying. There is another remarkable circumstance which 
seems to support Dr. Stark's conclusion, namely, that widows and 
widowers in France suffer in comparison with the married a very 
heavy rate of mortality; but Dr. Farr attributes this to the pov- 
erty and evil habits consequent on the disruption of the family, 
and to grief. On the whole we may conclude with Dr. Farr that 
the lesser mortality of married than of unmarried men, which 
seems to be a general law, "is mainly due to the constant elimina- 
"tion of imperfect types, and to the skillful selection of the finest 
"individuals out of each successive generation;" the selection re- 
lating only to the marriage state, and acting on all corporeal, in- 
tellectual, and moral qualities.^^ We may, therefore, infer that 

23 Dr. Farr, ibid. The quotations given below are extracted from the 
same striliing paper. 

24 I have taken the mean of the quinquennial means, given in 'The 
Tenth Annual Report of Births, Deaths, &c., in Scotland,' 1867. The 
quotation from Dr. Stark is copied from an article in the 'Daily News,' 
Oct. 17th, 1S6S, which Dr. Farr considers very carefully written. 

25 Dr. Duncan remarks ('Fecundity, Fertility,' &c., 1871, p. 334) on this 
subject: "At every age the healthy and beautiful go over from the 
"unmarried side to the married, leaving the unmarried columns 
"crowded with the sickly and unfortunate." 



CIVILIZED NATIONS. 137 

sound and good men who out of prudence remain for a time un- 
married, do not suffer a high rate of mortality. 

If the various checks specified in the two last paragraphs, and 
perhaps others as yet unknown, do not prevent the reckless, the | 
vicious and otherwise inferior members of society from increas- i 
ing at a quicker rate than the better class of men, the nation will 
retrograde, as has too often occurred in the history of the world. 
We must remember that progress is no invariable rule. It is 
very difficult to say why one civilized nation rises, becomes more 
powerful, and spreads more widely, than another; or why the 
same nation progresses more quickly at one time than at another. 
We can only say that it depends on an increase in the actual num- 
ber of the population on the number of the men endowed with 
high intellectual and moral faculties, as well as on their standard 
of excellence. Corporeal structure appears to have little influence, 
except so far as vigor of body leads to vigor of mind. 

It has been urged by several writers that as high intellectual 
powers are advantageous to a nation, the old Greeks, who stood 
some grades higher in intellect than any race that has ever 
existed,'^ ought, if the power of natural selection were real, to 
have risen still higher in the scale, increased in number, and 
stocked the whole of Europe. Here we have the tacit assumption, 
so often made with respect to corporeal structures, that there is 
some innate tendency towards continued development in mind and , 
body. But development of all kinds depends on many concur- \ 
rent favorable circumstances. Natural selection acts only tenta- t 
tively. Individuals and races may have acquired certain indis- 
putable advantages, and yet have perished from failing in other /^ . 
characters. The Greeks may have retrograded from a want of ^^r-^' 
coherence between the many small states, from the small size of 
their whole country, from the practice of slavery, or from extreme 
sensuality; for they did not succumb until "they were enervated 
"and corrupt to the very core."-^ The western nations of Europe, 
who now so immeasurably surpass their former savage progeni- 
tors, and stand at the summit of civilization, owe little or none 
of their superiority to direct inheritance from the old Greeks, 
though they owe much to the written works of that wonderful 
people. 

Who can positively say why the Spanish nation, so dominant at 
one time, has been distanced in the race. The awakening of the 
nations of Europe from the dark ages is a still more perplexing 
problem. At that early period, as Mr. Galton has remarked, al- 
most all the men of a gentle nature, those given to meditation or 

2^ See the ingenious and original argument on this subject by Mr. Gal- 
ton, 'Hereditary Genius,' pp. 340-342. 
27 Mr. Greg 'Fraser's Magazine,' Sept. 1868, p. 357. 



138 THE DESCENT OF MAN. 

culture of the mind, had no refuge except in the bosom of a 
Church which demanded celibacy;-^ and this could hardly fail to 
have had a deteriorating influence on each successive generation. 
During this same period the Holy Inquisition selected with ex- 
treme care the freest and boldest men in order to burn or im- 
prison them. In Spain alone some of the best men — those who 
doubted and questioned, and without doubting there can be no 
progress — were eliminated during three centuries at the rate of a 
thousand a year. The evil which the Catholic Church has thus 
effected is incalculable, though no doubt counterbalanced to a cer- 
tain, perhaps to a large, extent in other ways; nevertheless, 
Europe has progressed at an unparalleled rate. 
" The remarkable success of the English as colonists, compared 
A'to other European nations, has been ascribed to their "daring 
"and persistent energy;" a result which is well illustrated by com- 
paring the progress of the Canadians of English and French ex- 
traction; but who can say how the English gained their energy? 
There is apparently much truth in the belief that the wonderful 
progress of the United States, as well as the character of the peo- 
ple, are the results of natural selection; for the more energetic, 
restless, and courageous men from all parts of Europe have 
emigrated during the last ten or twelve generations to that great 
country, and have there succeeded best.-* Looking to the dis- 
tant future, I do not think that the Rev. Mr. Zincke takes an 
exaggerated view when he says:^'' "All other series of events — 
"as that v/hich resulted in the culture of mind in Greece, and 
"that which resulted in the empire of Rome — only appear to 
"have purpose and value when viewed in connection with, or 
"rather as subsidiary to. . . .the great stream of Anglo-Saxon emi- 
"gration to the west." Obscure as is the problem of the advance 
of civilization, we can at least see that a nation which produced 
during a lengthened period the greatest number of highly intel- 
lectual, energetic, brave, patriotic, and benevolent men, would 
generally prevail over less favored nations. 

Natural selection follows from the struggle for existence; and 
this from a rapid rate of increase. It is impossible not to regret 
bitterly, but whether wisely is another question, the rate at which 
man tends to increase; for this leads in barbarous tribes to in- 

28 'Hereditary Genius,' 1870, pp. 357-359. The Rev. F. W. Farrar 'Fras- 
er's Mag.,' Aug. 1870, p. 257, advances arguments on the other side. Sir 
C. Lyell had already ('Principles of Geology,' vol. ii. 1868, p. 489) in a 
striking passage called attention to the evil influence of the Holy In- 
quisition in having, through selection, lowered the general standard 
of intelligence in Europe. 

29 Mr. Galton, 'Macmillan's Magazine,' August, 1865, p. 325. See, also 
'Nature,' 'On Darwinism and National Life,' Dec. 1869, p. 184. 

so 'Last Winter in the United States,' 1868, p. 29. 



CIVILIZED NATIONS. 139 

fanticide and many other evils, and in civilized nations to abject 
poverty, celibacy, and to the late marriages of the prudent. But 
as man suffers from the same physical evils as the lower animals, 
he has no right to expect an immunity from the evils consequent 
on the struggle for existence. Had he not been subjected during 
primeval times to natural selection, assuredly he would never 
have attained to his present rank. Since we see in many parts of 
the world enormous areas of the most fertile land capable of sup- 
porting numerous happy homes, but peopled only by a few wan- 
dering savages, it might be argued that the struggle for existence 
had not been sufficiently severe to force man upwards to his high- 
est standard. Judging from all that we know of man and the 
lower animals, there has always been sufficient variability in their 
intellectual and moral faculties, for a steady advance through 
natural selection. No doubt such advance demands many favora- 
ble concurrent circumstances; but it may be well doubted wheth- 
er the most favorable would have sufficed, had not the rate of in- 
crease been rapid, and the consequent struggle for existence ex- 
tremely severe. It even appears from what we see, for instance, 
in parts of S. America, that a people which may be called civ- 
ilized, such as the Spanish settlers, is liable to become indolent 
and to retrograde, when the conditions of life are very easy. With 
highly civilized nations continued progress depends in a subordi- 
nate degree on natural selection; for such nations do not sup- 
plant and exterminate one another as do savage tribes. Neverthe- 
less the more intelligent members within the same community 
will succeed better in the long run than the inferior, and leave 
a more numerous progeny, and this is a form of natural selection. 
The more efficient causes of progress seem to consist of a good 
education during youth whilst the brain is impressible, and of 
a high standard of excellence, inculcated by the ablest and best 
men, embodied in the laws, customs and traditions of the nation, 
and enforced by public opinion. It should, however, be borne in 
mind, that the enforcement of public opinion depends on our 
appreciation of the approbation and disapprobation of others; 
and this appreciation is founded on our sympathy, which it can 
hardly be doubted was originally developed through natural se- 
lection as one of the most important elements of the social in- 
stincts.^^ 

On the evidence that all civilized nations were once barbarous. — 
The present subject has been treated in so full and admirable a 
manner by Sir J. Lubbock,^^ Mr. Tylor, Mr. M'Lennan, and others, 

^^ I am much indebted to Mr. John Morley for some good criticisms 
on this subject: see, also, Broca, 'Les Selections,' 'Revue d'Anthro- 
pologie,' 1872. 

32 'On the Origin of Civilization,' 'Proc. Ethnological Soc' Nov. 26, 
1867. 



140 THE DESCENT OP MAN. 

that I need here give only the briefest summary of their results. 
The arguments recently advanced by the Duke of Argyll'^* and 
formerly by Archbishop Whately, in favor of the belief that man 
came into the world as a civilized being, and that all savages 
have since undergone degradation, seem to me weak in com- 
parison with those advanced on the other side. Many nations, no 
doubt, have fallen away in civilization, and some may have lapsed 
into utter barbarism, though on this latter head I have met with 
no evidence. The Fuegians were probably compelled by other 
conquering hordes to settle in their inhospitable country, and they 
may have become in consequence somewhat more degraded; but it 
would be difficult to prove that they have fallen much below the 
Botocudos, who inhabit the finest parts of Brazil. 

The evidence that all civilized nations are the descendants of 
barbarians, consists, on the one side, of clear traces of their 
former low condition in still-existing customs, beliefs, language. 
&c.; and on the other side, of proofs that savages are independ- 
ently able to raise themselves a few steps in the scale of civiliza- 
tion, and have actually thus risen. The evidence on the first head 
is extremely curious, but cannot be here given: I refer to such 
cases as that of the art of enumeration, which, as Mr. Tylor 
clearly shows by reference to the words still used in some places, 
originated in counting the fingers, first of one hand and then of 
the other, and lastly of the toes. We have traces of this in our 
own decimal system, and in the Roman numerals, where, after the 
v., which is supposed to be an abbreviated picture of a human 
hand, we pass on to VI., &c., when the other hand no doubt was 
used. So again, "when we speak of three-score and ten, we are 
"counting by the vigesimal system, each score thus ideally made, 
"standing for 20 — for 'one man' as a Mexican or Carib would put 
"it."^* According to a large and increasing school of philologists, 
every language bears the marks of its slow and gradual evolution. 
So it is with the art of writing, for letters are rudiments of pic- 
torial representations. It is hardly possible to read Mr. M'Len- 
nan's work^^ and not admit that almost all civilized nations still 
retain traces of such rude habits as the forcible capture of wives. 
What ancient nation, as the same author asks, can be named 

33 'Primeval Man,' 1869. 

3* 'Royal Institution of Great Britain,' March 15, 1867. Also, 'Re- 
searches into the Early History of Mankind,' 1865. 

35 'Prihaitive Marriage,' 1865. See, likewise, an excellent article, evi- 
dently by the same author, in the 'North British Review,' July, 1869. 
Also, Mr. L. H. Morgan, 'A Conjectural Solution of the Origin of the 
Class System of Relationship,' in 'Proc. American Acad, of Sciences,' 
vol. vii. Feb. 1868. Prof. SchaafChausen ('Anthropolog. Review,' Oct. 
1869, p. 373) remarks on "the vestiges of human sacrifices found both 
"in Homer and the Old Testament." 



NATIONS. 14i 

that was originally monogamous? The primitive idea of justice, 
as shown by the law of battle and other customs of which vestiges 
still remain, was likewise most rude. Many existing superstitions 
are the remnants of former false religious beliefs. The highest 
form of religion — the grand idea of God hating sin and loving 
righteousness — was unknown during primeval times. 

Turning to the other kind of evidence; Sir J. Lubbock has 
shown that some savages have recently improved a little in 
some of their simpler arts. From the extremely curious ac- 
count which he gives of the weapons, tools, and arts, in use 
amongst savages in various parts of the world, it cannot be 
doubted that these have nearly all been independent discoveries, 
excepting perhaps the art of making fire.'^'^ The Australian 
boomerang is a good instance of one such independent discovery. 
The Tahitians when first visited had advanced in many respects 
beyond the inhabitants of most of the other Polynesian islands. 
There are no just grounds for the belief that the high culture of 
the native Peruvians and Mexicans was derived from abroad;" 
many native plants were there cultivated, and a few native ani- 
mals domesticated. We should bear in mind that, judging from 
the small influence of most missionaries, a wandering crew from 
some semi-civilized land, if washed to the shores of America, 
would not have produced any marked effect on the natives, unless 
they had already become somewhat advanced. Looking to a very 
remote period in the history of the world, we find, to use Sir J. 
Lubbock's well-known terms, a paleolithic and neolithic period; 
and no one will pretend that the art of grinding rough flint tools 
was a borrowed one. In all parts of Europe, as far east as Greece, 
in Palestine, India, Japan, New Zealand, and Africa, including 
Egypt, flint tools have been discovered in abundance; and of their 
use the^^exTsling inhabitants retain no tradition. There is also 
indirect evidence of their former use by the Chinese and ancient 
Jews. Hence there can hardly be a doubt that the inhabitants of 
these countries, which include nearly the whole civilized world, 
were once in a barbarous condition. To believe that man was 
aboriginally civilized and then suffered utter degradation in so 
many regions, is to take a pitiably low view of human nature. It 
is apparently a truer and more cheerful view that progress has 
been much more general than retrogression; that man has risen, 
though by slow and interrupted steps, from a lowly condition to 
the highest standard as yet attained by him in knowledge, morals 
and religion. 

38 Sir J. Lubbock, 'Prehistoric Times,' 2nd edit. 1869, chap. xv. and 
xvi. et passim. See, also, the excellent 9th chapter in Tyler's 'Early 
History of Mankind,' 2nd edit., 1870. 

3^ Dr. F. Muller has made some good remarks to this effect in the 
'Reise der Novara: Anthropolog. Theil,' Abtheil. iii. 1868, s. 127. 



142 THH DESCENT OP MAN. 



CHAPTER VI. 

ON THE AFFINITIES AND GENEALOGY OF MAN. 

Position of man in the animal series — The natural system genealogical 
—Adaptive characters of slight value— Various small points of re- 
semblance between man and the Quadrumana— Rank of man in the 
natural system— Birthplace and antiquity of man— Absence of fossil 
connecting-links— Lower stages in the genealogy of man, as in- 
ferred, firstly from his affinities and secondly from his structured- 
Early androgynous condition of the Vertebrata— Conclusion. 

Even if it be granted that the difference between man and his 
nearest allies is as great in corporeal structure as some natu- 
ralists maintain, and although we must grant that the difference 
between them is immense in mental power, yet the facts given in 
the earlier chapters appear to declare, in the plainest manner, 
that man is descended from some lower form, notwithstanding 
that connecting links have not hitherto been discovered. 

Man is liable to numerous, slight, and diversified variations, 
which are induced by the same general causes, are governed 
and transmitted in accordance with the same general laws, as in 
the lower animals. Man has multiplied so rapidly, that he has 
necessarily been exposed to struggle for existence, and con- 
sequently to natural selection. He has given rise to many races, 
some of which differ so much from each other, that they have 
often been ranked by naturalists as distinct species. His bodj"" 
is constructed on the same homological plan as that of other 
mammals. He passes through the same phases of embryological 
development. He retains many rudimentary and useless struc- 
tures, which no doubt were once serviceable. Characters occa- 
sionally make their re-appearance in him, which we have reason 
to believe were possessed by his early progenitors. If the origin 
of man has been wholly different from that of all other animals, 
these various appearances would be mere empty deceptions; 
but such an admission is incredible. These appearances, on the 
other hand, are intelligible, at least to a large extent, if man 
is the co-descendant with other mamma,ls of some unknown and 
lower form. 

Some naturalists, from being deeply impressed with the mental 



AFFINITIES AND GENEALOGY. 143 

and spiritual powers of man, have divided the whole organic 
world into three kingdoms, the Human, the Animal, and the 
Vegetable, thus giving to man a separate kingdom.^ Spiritual 
powers cannot be compared or classed by the naturalist: but he 
may endeavor to show, as I have done, that the mental faculties 
of man and the lower animals do not differ in kind, although 
immensely in degree. A difference in degree, however great, 
does not justify us in placing man in a distinct kingdom, as will 
perhaps be best illustrated by comparing the mental powers of 
two insects, namely, a coccus or scale-insect and an ant, which 
undoubtedly belong to the same class. The difference is here 
greater than, though of a somewhat different kind from, that 
between man and the highest mammal. The female coccus, whilst 
young, attaches itself by its proboscis to a plant; sucks the sap, 
but never moves again; is fertilized and lays eggs; and this is its 
whole history. On the other hand, to describe the habits and 
mental powers of worker-ants, would require, as Pierre Ruber 
has shown, a large volume; I may, however, briefly specify a few 
points. Ants certainly communicate information to each other, 
and several unite for the same work, or for games of play. They 
recognize their fellow-ants after months of absence, and feel sym- 
pathy for each other. They build great edifices, keep them clean, 
close the doors in the evening, and post sentries. They make 
roads as well as tunnels under rivers, and temporary bridges over 
them, by clinging together. They collect food for the community, 
and when an object, too large for entrance, is brought to the nest, 
they enlarge the door, and afterwards build it up again. They 
store up seeds, of which they prevent the germination, and which, 
if damp, are brought up to the surface to dry. They keep aphides 
and other insects as milch-cows. They go out to battle in regular 
bands, and freely sacrifice their lives for the common weal. They 
emigrate according to a preconcerted plan. They capture slaves. 
They move the eggs of their aphides, as well as their own eggs 
and cocoons, into warm parts of the nest, in order that they may 
be quickly hatched; and endless similar facts could be given.^ On 
the whole, the difference in mental power between an ant and a 
coccus is immense; yet no one has ever dreamed of placing these 
insects in distinct classes, much less in distinct kingdoms. No 
doubt the difference is bridged over by other insects; and this 

1 Isidore Geoffrey St.-Hilaire gives a detailed account of the position 
assigned to man bj' various naturalists in their classifications: 'Hist. 
Nat. Gen.' torn. ii. 1859, pn. 170-189. 

2 Some of the most interesting facts ever published on the habits of 
ants are given by Mr. Belt, in his 'Naturalist in Nicaragua,' 1874. See, 
also, Mr. Moggridge's admirable work, 'Harvesting Ants,' &c., 1873, 
also 'L'Instinct chez les Insectes,' by M. George Pouchet, 'Revue des 
Deux Mondes,' F.eb. 1870, p. 682. 

2 



144 THE DESCENT OP MAN. 

is not the case with man and the higher apes. But we have 
every reason to believe that the breaks in the series are simply 
the results of many forms having become extinct. 

Professor Owen, relying chiefly on the structure of the brain, 
has divided the mammalian series into four sub-classes. One of 
these he devotes to man; in another he places both the Marsu- 
pials and the Monotremata; so that he makes man as distinct 
from all other mammals as are these two latter groups conjoined. 
This view has not been accepted, as far as I am aware, by any 
naturalist capable of forming an independent judgment^ and 
therefore need not here be further considered. 

We can understand why a classification founded on any single 
character or organ — even an organ so wonderfully complex and 
important as the brain — or on the high development of the mental 
faculties, is almost sure to prove unsatisfactory. This principle 
has indeed been tried with hymenopterous insects; but when thus 
classed by their habits or instincts, the arrangement proved thor- 
oughly artificial.^ Classifications may, of course, be based on any 
character whatever, as on size, color, or the element inhabited; but 
naturalists have long felt a profound conviction that there is a 
natural system. This system, it is now generally admitted, must 
be, as far as possible, genealogical in arrangement, — that is the 
co-descendants of the same form must be kept together in one 
group, apart from the co-descendants of any other form; but if 
the parent-forms are related, so will be their descendants, and 
the two groups together will form a larger group. The amount of 
difference between the several groups — that is the amount of 
modification which each has undergone — is expressed by such 
terms as genera, families, orders, and classes. As we have no 
record of the lines of descent, the pedigree can be discovered only 
by observing the degrees of resemblance between the beings which 
are to be classed. For this object numerous points of resem- 
blance are of much more importance than the amount of sim- 
ilarity or dissimilarity in a few points. If two languages were 
found to resemble each other in a multitude of words and points 
of construction, they would be universally recognized as having 
sprung from a common source, notwithstanding that they differed 
greatly in some few words or points of construction. But with 
organic beings the points of resemblance must not consist of 
adaptations to similar habits of life: two animals may, for in- 
stance, have had their whole frames modified for living in the 
water, and yet they will not be brought any nearer to each other 
in the natural system. Hence we can see how it is that resem- 
blances in several unimportant structures, in useless and rudi- 
mentary organs, or not now functionally active, or in an embry- 



3 Westwood, 'Modern Class of Insects,' vol. ii. 1840, p. 87. 

i 



AFFINITIES AND GENEALOGY. 145 

ological condition, are by far the most serviceable for classifica- 
tion; for they can hardly be due to adaptations within a late 
period; and thus they reveal the old lines of descent or of true 
affinity. 

We can further see why a great amount of modification in 
some one character ought not to lead us to separate widely any 
two organisms. A part which already differs much from the 
same part in other allied forms has already, according to the 
theory of evolution, varied much; consequently it would (as long 
as the organism remained exposed to the same exciting condi- 
tions) be liable to further variations of the same kind; and 
these, if beneficial, would be preserved, and thus be continually 
augmented. In many cases the continued development of a part, 
for instance, of the beak of a bird, or of the teeth of a mammal, 
would not aid the species in gaining its food, or for any other 
object; but with man we can see no definite limit to the con- 
tinued development of the brain and mental faculties, as far as 
advantage is concerned. Therefore in determining the position 
of man in the natural or genealogical system, the extreme de- 
velopment of his brain ought not to outweigh a multitude of 
resemblances in other less important or quite unimportant points. 

The greater number of naturalists who have taken into con- 
sideration the whole structure of man, including his mental 
faculties, have followed Blumenbach and Cuvier, and have placed 
man in a separate Order, under the title of the Bimana, and 
therefore on an equality with the orders of the Quadrumana, 
Carnivora, &c. Recently many of our best naturalists have 
recurred to the view first propounded by Linnasus, so remarkable 
for his sagacity, and have placed man in the same Order with 
the Quadrumana, under the title of the Primates. The justice of 
this conclusion will be admitted: for in the first place, we must 
bear in mind the comparative insignificance for classification 
of the great development of the brain in man, and that the 
strongly-marked differences between the skulls of man and the 
Quadrumana (lately insisted upon Bischoff, Aeby, and others, 
apparently follow from their differently developed brains. In 
the second place, we must remember that nearly all the other 
and more important differences between man and the Quadrumana 
are manifestly adaptive in their nature, and relate chiefly to the 
erect position of man; such as the structure of his hand, foot, 
and pelvis, the curvature of his spine, and the position of his 
head. The family of Seals offers a good illustration of the small 
importance of adaptive characters for classification. These 
animals differ from all other Carnivora in the form of their 
bodies and in the structure of their limbs, far more than does 
man from the higher apes; yet in most systems, from that of 

11 



146 THE DESCENT OF MAN. 

Cuvier to the most recent one by Mr. Flower/ seals are ranked 
as a mere family in the Order of the Carnivora. If man had not 
been his own classifier, he would never have thought of founding 
a separate order for his own reception. 

It would be beyond my limits, and quite beyond my knowledge, 
even to name the innumerable points of structure in which man 
agrees with the other Primates. Our great anatomist and phil- 
osopher. Prof. Huxley, has fully discussed this subject,^ and con- 
cludes that man in all parts of his organization differs less from 
the higher apes, than these do from the lower members of the 
same group. Consequently there "is no justification for placing 
"man in a distinct order." 

In an early part of this work I brought forward various facts, 
showing how closely man agrees in constitution with the higher 
mammals; and this agreement must depend on our close sim- 
ilarity in minute structure and chemical composition. I gave, 
as instances, our liability to the same diseases, and to the attacks 
of allied parasites; our tastes in common for the same stimu- 
lants, and the similar effects produced by them, as well as by 
various drugs, and other such facts. 

As small unimportant points of resemblance between man and 
the Quadrumana are not commonly noticed in systematic works, 
and as, when numerous, they clearly reveal our relationship, I 
will specify a few such points. The relative position of our fea- 
tures is manifestly the same; and the various emotions are dis- 
played by nearly similar movements of the muscles and skin, 
chiefly above the eyebrows and round the mouth. Some few 
expressions are, indeed, almost the same, as in the weeping of 
certain kinds of monkeys and in the laughing noise made by 
others, during which the corners of the mouth are drawn back- 
wards, and the lower eyelids wrinkled. The external ears are 
curiously alike. In man the nose is much more prominent than 
in most monkeys; but we may trace the commencement of an 
aquiline curvature in the nose of the Hoolock Gibbon; and this 
in the Semnopithecus nasica is carried to a ridiculous extreme. 

The faces of many monkeys are ornamented with beards, whis- 
kers, or moustaches. The hair on the head grows to a great 
length in some species of Semnopithecus;^ and in the Bonnet 
monkey (Macacus radiatus) it radiates from a point on the crown, 
with a parting down the middle. It is commonly said that the 
forehead gives to man his noble and intellectual appearance; but 
the thick hair on the head of the Bonnet monkey terminates 
downwards abruptly, and is succeeded by hair so short and fine 

* 'Proc. Zoolog. Soc' 1S63, p. 4. 

s 'Evidence as to Man's Place in Nature,' 1863, p. 70, et passim. 

« Isid. Geoffrey, 'Hist. Nat. Gen.' torn. ii. 1859, p. 217. 



Ai^FINITIES AND GENEALOGY. 147 

that at a little distance the forehead, with the exception of the 
eyebrows, appears quite naked. It has been erroneously asserted 
that eyebrows are not present in any monkey. In the species 
just named the degree of nakedness of the forehead differs in 
different individuals; and Eschricht states' that in our children 
the limit between the hairy scalp and the naked forehead is 
sometimes not well defined; so that here we seem to have a 
trifling case of reversion to a progenitor, in whom the forehead 
had not as yet become quite naked. 

It is well known that the hair on our arms tends to converge 
from above and below to a point at the elbow. This curious 
arrangement, so unlike that in most of the lower mammals, is 
common to the gorilla, chimpanzee, orang, some species of Hy- 
lobates, and even to some few American monkeys. But in Hylo- 
bates agilis the hair on the fore-arm is directed downwards or 
towards the wrist in the ordinary manner; and in H. lar it is 
nearly erect, with only a very slight forward inclination; so that 
in this latter species it is in a transitional state. It can hardly 
be doubted that with most mammals the thickness of the hair on 
the back and its direction, is adapted to throw off the rain; even 
the transverse hairs on the fore-legs of a dog may serve for this 
end when he is coiled up asleep. Mr. Wallace, who has carefully 
studied the habits of the orang, remarks that the convergence of 
the hair towards the elbow on the arms of the orang may be 
explained as serving to throw off the rain, for this animal during 
rainy weather sits with its arms bent, and with the hands clasped 
round a branch or over its head. According to Livingstone, the 
gorilla also "sits in pelting rain with his hands over his head."^.. 
If the above explanation is correct, as seems probable, the direc- , 
tion of the hair on our own arms offers a curious record of our/ 
former state; for no one supposes that it is now of any use in 
throwing off the rain; nor, in our present erect condition, is it 
properly directed for this purpose. 

It would, however, be rash to trust too much to the principle 
of adaptation in regard to the direction of the hair in man or his 
early progenitors; for it is itnpossible to study the figures given 
by Eschricht of the arrangement of the hair on the human foetus 
(this being the same as in the adult) and not agree with this 
excellent observer that other and more complex causes have 
intervened. The points of convergence seem to stand in some 
relation to those points in the embryo which are last closed in 
during development. There appears, also, to exist some relation 

' 'Ueber die Richtung der Haare,' &c., Muller's 'Archiv fur Anat. und 
Phys' 1837, s. 51. 
8 Quoted by Reade, 'The African Sketch Book,' vol. 1. 1873, p. 152. 



148 THE DESCENT OF MAN. 

between the arrangement of the hair on the limbs, and the course 
of the medullary arteries.'' 

It must not be supposed that the resemblances between man 
and certain apes in the above and many other points — such as in 
having a naked forehead, long tresses on the head, «S:c. — are all 
necessarily the result of unbroken inheritance from a common 
progenitor, or of subsequent reversion. Many of these resem- 
blances are more probably due to analogous variation, which 
follows, as I have elsewhere attempted to show,^" from co-de- 
scended organisms having a similar constitution, and having been 
acted on by like causes inducing similar modifications. With re- 
spect to the similar direction of the hair on the fore-arms of man 
and certain monkeys, as this character is common to almost all 
the anthropomorphous apes, it may probably be attributed to in- 
heritance; but this is not certain, as some very distinct American 
monkeys are thus characterized. 

Although, as we have now seen, man has no jiist right to form 
a separate Order for his own reception, he may perhaps claim a 
distinct Sub-order or Family. Prof. Huxley, in his last work," 
divides the Primates into three Sub-orders; namely, the An- 
thropidse with man alone, the Simiadae including monkeys of all 
kinds, and the Lemuridas with the diversified genera of lemurs. 
As far as differences in certain important points of structure are 
concerned, man may no doubt rightly claim the rank of a Sub- 
order; and this rank is too low if we look chiefiy to his mental 
faculties. Nevertheless, from a genealogical point of view it 
appears that this rank is too high, and that man ought to form 
merely a Family, or possibly even only a Sub-family. If we 
imagine three lines of descent proceeding from a common stock, 
it is quite conceivable that two of them might after the lapse of 
ages be so slightly changed as still to remain as species of the 
same genus, whilst the third line might become so greatly modi- 
fied as to deserve to rank as a distinct Sub-family, Family, or 
even Order. But in this case it is almost certain that the third 
line would still retain through inheritance numerous small points 
of resemblance with the other two. Here, then, would occur 
the difficulty, at present insoluble, how much weight we ought 
to assign in our classifications to strongly-marked differences in 
some few points, — that is, to the amount of modification under- 

» On the hair in Hylobates, see 'Nat. Hist, of Mammals,' by C. L. 
Martin, 1841, p. 415. Also, Isid. Geoffroy on the American monkeys and 
other kinds, 'Hist. Nat. Gen.' vol. ii. 1859, p. 216, 243. Eschricht ibid. 
s, 46, 55, 61. Owen, 'Anat. of Vertebrates,' vol. iii. p. 619. Wallace, 'Con- 
tributions to the Theory of Natural Selection,' 1870, p. 344. 

10 'Origin of Species,' 5th edit. 1S69, p. 194. 'The Variation of Animals 
and Plants under Domestication,' vol. ii. 1868, p. 348. 

u 'An Introduction to the Classification of Animals,' 1869, p. 99. 



AFFINITIES AND GENEALOGY. 149 

gone; and how much to close resemblance in numerous unim- 
portant points, as indicating the lines of descent or genealogy. 
To attach much weight to the few but strong differences is the 
most obvious and perhaps the safest course, though it appears 
more correct to pay great attention to the many small resem- 
blances, as giving a truly natural classification. 

In forming a judgment on this head with reference to man, we 
must glance at the classification of the Simiadse. This family is 
divided by almost all naturalists into the Catarhine group, or 
Old World monkeys, all of which are characterized (as their 
name expresses) by the peculiar structure of their nostrils, and by 
having four premolars in each jaw; and into the Platyrhine 
group or New World monkeys (including two very distinct sub- 
groups), all of which are characterized by differently constructed 
nostrils, and by having six premolars in each jaw. Some other 
small differences might be mentioned. Now man unquestionably 
belongs in his dentition, in the structure of his nostrils, and 
some other respects, to the Catarhine or Old World division; nor 
does he resemble the Platyrhines more closely than the Catar- 
hines in any characters, excepting in a few of not much import- 
ance and apparently of an adaptive nature. It is therefore against 
all probability that some New World species should have for- 
merly varied and produced a man-like creature, with all the dis- 
tinctive characters proper to the Old World division; losing at 
the same time all its own distinctive characters. There can, con- 
sequently, hardly be a doubt that man is an off-shoot from the 
Old World Simian stem; and that under a genealogical point of 
view, he must be classed with the Catarhine division.^^ 

The anthropomorphous apes, namely, the gorilla, chimpanzee, 
orang, and hylobates, are by most naturalists separated from the 
other Old World monkeys, as a distinct sub-group. I am aware 
that Gratiolet, relying on the structure of the brain, does not 
admit the existence of this sub-group, and no doubt it is a broken 
one. Thus the orang, as Mr. St. G. Mivart remarks,^^ "is one of 
"the most peculiar and aberrant forms to be found in the Order." 
The remaining non-anthropomorphous Old World monkeys, are 
again divided by some naturalists into two or three smaller sub- 
groups; the genus Semnopithecus, -mth its peculiar sacculated 
stomach, being the type of one such sub-group. But it appears 

12 This is nearly the same classification as that provisionally adopted 
by Mr. St. George Mivart ('Transact. Pliilosoph. Soc' 1867, p. 300), who, 
after separating the Lemuridae, divides the remainder of the Primates 
into the Hominidae, the Simiadae which answer to the Catarhines, the 
Cebidae, and the Hapalidae,— these two latter groups ansv/ering- to the 
Platyrhines. Mr. Mivart still abides by the same view; see 'Nature,' 
1871, p. 4S1. 

13 'Transact. Zoolog. Soc' vol. vi. 1867, p. 214, 

11 



150 THE DESCENT OF MAN. 

from M. Gaudry's wonderful discoveries in Attica, that during 
the Miocene period a form existed there, which connected Sem- 
nopithecus and Macacus; and this probably illustrates the man- 
ner in which the other and higher groups were once blended to- 
gether. 

If the anthropomorphous apes be admitted to form a natural 
sub-group, then as man agrees with them, not only in all those 
characters which he possesses in common with the whole Catar- 
hine group, but in other peculiar characters, such as the absence 
of a tail and of callosities, and in general appearance, we may 
infer that some ancient member of the anthropomorphous sub- 
group gave birth to man. It is not probable that, through the 
law of analogous variation, a member of one of the other lower 
sub-groups should have given rise to a man-like creature, re- 
sembling the higher anthropomorphous apes in so many respects. 
No doubt man, in comparison with most of his allies, has under- 
gone an extraordinary amount of modification, chiefly in conse- 
quence of the great development of his brain and his erect po- 
sition; nevertheless, we should bear in mind that he "is but one 
"of several exceptional forms of Primates."^* 

Every naturalist, who believes in the principle of evolution, 
will grant that the two main divisions of the Simiadae, namely 
the Catarhine and Platyrhine monkeys, with their sub-groups, 
have all proceeded from some one extremely ancient progenitor, 
The early descendants of this progenitor, before they had diverged 
to any considerable extent from each other, would still have 
formed a single natural group; but some of the species or incip- 
ient genera would have already begun to indicate by their diverg- 
ing characters the future distinctive marks of the Catarhine and 
Platyrhine divisions. Hence the members of this supposed an- 
cient group would not have been so uniform in their dentition, 
or in the structure of their nostrils, as are the existing Catarhine 
monkeys in one way and the Platyrhines in another way, but 
would have resembled in this respect the allied Lemuridse, which 
differ greatly from each other in the form of their muzzles,^^ 
and to an extraordinary degree in their dentition. 

The Catarhine and Platyrhine monkeys agree in a multitude of 
characters, as is shown by their unquestionably belonging to one 
and the same Order. The many characters which they possess 
in common can hardly have been independently acquired by so 
many distinct species; so that these characters must have been 
inherited. But a naturalist would undoubtedly have ranked as 
an ape or a monkey, an ancient form which possessed many char- 

"Mr. St. G. Mivart, 'Transact. Phil. Soc' 1867, p. 410. 
" Messrs. Murie and Mivart on the Lemuroidea, 'Transact. Zoologr. 
Soc.' vol. vii. 1869, p. 5. 



AFFINITIES AND GENEALOGY. 151 

acters common to the Catarhine and Platyrhine monkeys, other 
characters in an intermediate condition, and some few, perhaps, 
distinct from those now found in either group. And as man 
from a genealogical point of view belongs to the Catarhine or 
Old World stock, we must conclude, however much the conclusion 
may revolt our pride, that our early progenitors would have 
been properly thus designated.^^ But we must not fall into the 
error of supposing that the early progenitor of the whole Simian 
stock, including man, was identical with, or even closely re- 
sembled, any existing ape or monkey. 

On the Birthplace and Antiquity of Man.— We are naturally 
led to enquire, where was the birthplace of man at that stage of 
descent when our progenitors diverged from the Catarhine stock? 
The fact that they belonged to this stock clearly shows that 
they inhabited the Old World; but not Australia nor any oceanic 
island, as we may infer from the laws of geographical distribu- 
tion. In each great region of the world the living mammals are 
closely related to the extinct species of the same region. It is 
therefore probable that Africa was formerly inhabited by extinct 
apes closely allied to the gorilla and chimpanzee; and as these two 
species are now man's nearest allies, it is somewhat more probable 
that our early progenitors lived on the African continent than 
elsewhere. But it is useless to speculate on this subject; for two 
or three anthropomorphous apes, one the Dryopithecus" of Lartet, 
nearly as large as a man, and closely allied to Hylobates, existed 
in Europe during the Miocene age; and since so remote a period 
the earth has certainly undergone many great revolutions, and 
there has been ample time for migration on the largest scale. 

At the period and place, whenever and wherever it was, when 
man first lost his hairy covering, he probably inhabited a hot 
country; a circumstance favorable for the frugiferous diet on 
which, judging from analogy, he subsisted. We are far from 
knowing how long ago it was when man first diverged from the 
Catarhine stock; but it may have occurred at an epoch as remote 
as the Eocene period; for that the higher apes had diverged 
from the lower apes as early as the Upper Miocene period is 
shown by the existence of the Dryopithecus. We are also quite 
ignorant at how rapid a rate organisms, v/hether high or low 
in the scale, may be modified under favorable circumstances; we 

1^ Hackel has come to this same conclusion. See 'Ueber die Entste- 
htmg- des Menschengeschlechts,' in Virchow's 'Sammlung'. g-emein. 
wissen. Vortrage,' 1868, s. 61. Also his 'Naturliche Schopfungsg-e- 
schichte,' 1868, in which he gives in detail his views on the genealogy 
of man. 

17 Dr. C. Forsyth Major, 'Sur les Singes Fossiles trouves on Italia;' 
'Soc. Ital. des So. Nat.' torn. xv. 1872. 



152 THE DESCENT OF MAN. 

knoAv, however, that some have retained the same form during 
an enormous lapse of time. From what we see going on under 
domestication, we learn that some of the co-descendants of the 
same species may he not at all, some a little, and some greatly 
changed, all within the same period. Thus it may have been 
with man, who has undergone a great amount of modification in 
certain characters in comparison with the higher apes. 

The great break in the organic chain between man and his 
nearest allies, which cannot be bridged over by any extinct or 
living species, has often been advanced as a grave objection to 
the belief that man is descended from some lower form; but this 
objection will not appear of much weight to those who, from 
general reasons, believe in the general principle of evolution. 
Breaks often occur in all parts of the series, some being wide, 
sharp and defined, others less so in various degrees; as between 
the orang and its nearest allies — between the Tarsius and the 
other Lemuridse — between the elephant, and in a more striking 
manner between the Ornithorhynchus or Echidna, and all other 
mammals. But these breaks depend merely on the number of 
related forms which have become extinct. At some future period, 
not very distant as measured by centuries, the civilized races 
of man will almost certainly exterminate, and replace, the savage 
races throughout the world. At the same time the anthropomor- 
phous apes, as Professor Schaaffhausen has remarked,^^ will no 
doubt be exterminated. The break between man and his nearest 
allies will then be wider, for it will intervene between man in 
a more civilized state, as we may hope, even than the Caucasian, 
and some ape as low as a baboon, instead of as now between the 
negro or Australian and the gorilla. 

With respect to the absence of fossil remains, serving to con- 
nect man with his ape-like progenitors, no one will lay much 
stress on this fact who reads Sir C. Lyell's discussion,^^ where 
he shows that in all the vertebrate classes the discovery of fossil 
remains has been a very slow and fortuitous process. Nor 
should it be forgotten that those regions which are the most 
likely to afford remains connecting man with some extinct ape- 
like creature, have not as yet been searched by geologists. 

Lower Stages in the Genealogy of Man. — We have seen that 
man appears to have diverged from the Catarhines or Old World 
division of the Simiadse, after these had diverged from the New 
World division. We will now endeavor to follow the remote 
traces of his genealogy, trusting principally to the mutual affin- 



18 'Anthropolog-ical Review,' April, 1SG7, p. 236. 

19 'Elements of Geology,' 1865, pp. 5S3-585. 'Antiquity of Man,' 1863, 
p. 145. 



JLFTINITIES AND GENEALOGY. 153 

ities between the various classes and orders, witli some slight 
reference to the periods, as far as ascertained, of their suc- 
ce.-!sive appearance on the earth. The Lemuridas stand below 
and near to the Simiadee, and constitute a very distinct family 
of the Primates, or, according to Hackel and others, a distinct 
Order. This group is diversified and broken to an extraordinary 
degree, and includes many aberrant forms. It has, therefore, 
probably suffered much extinction. Most of the remnants sur- 
vive on islands, such as Madagascar and the Malayan archipelago, 
where they have not been exposed to so severe a competition as 
they would have been on well-stocked continents. This group 
likewise presents many gradations, leading, as Huxley remarks,^^ 
"insensibly from the crown and summit of the animal creation 
"down to creatures from which there is but a step, as it seems, 
"to the lowest, smallest, and least intelligent of the placental 
"mammalia." From these various considerations it is probable 
that the Simiadae were originally developed from the progenitors 
of the existing Lemuridas; and these in their turn from forms 
standing very low in the mammalian series. 

The Marsupials stand in many important characters below the 
placental mammals. They appeared at an earlier geological 
period, and their range was formerly much more extensive than 
at present. Hence the Placentata are generally supposed to have 
been derived from the Implacentata or Marsupials; not, however, 
from forms closely resembling the existing Marsupials, but from 
their early progenitors. The Monotremata are plainly allied to 
the Marsupials, forming a third and still lower division in the 
great mammalian series. They are represented at the present 
day solely by the Ornithorhynchus and Echidna; and these two 
forms may be safely considered as relics of a much larger group 
representatives of which have been preserved in Australia through 
some favorable concurrence of circumstances. The Monotremata 
are eminently interesting, as leading in several important points 
of structure towards the class of reptiles. 

In attempting to trace the genealogy of the Mammalia, and 
therefore of man, lower down in the series, we become involved 
in greater and greater obscurity; but as a most capable judge, 
Mr. Parker, has remarked, we have good reason to believe, that 
no true bird or reptile intervenes in the direct line of descent. 
He who wishes to see what ingenuity and knowledge can effect, 
may consult Prof. Hackel's works.^^ I will content myself with 

20 'Man's Place in Nature,' p. 105. 

-1 Elaborate tables are given in his 'Generelle Morphologie' (B. li. 
s. cliii. and s. 425); and with more especial reference to man in his 
'Naturliche Schopfungschichte,' 1868. Prof. Huxley, in reviewing 
this latter work i('The Academy,' 1869, p. 42) says, that he considers the 
phylum or lines of descent of the Vertebrata to be admirably discussed 



154 THE DESCENT OF MAN. 

a few general remarks. Every evolutionist will admit that the 
five great vertebrate classes, namely, mammals, birds, reptiles, 
amphibians, and fishes, are descended from some one prototype; 
for they have much in common, especially during their embryonic 
state. As the class of fishes is the most lowly organized, and 
appeared before the others, we may conclude that all the members 
of the vertebrate kingdom are derived from some fish-like animal. 
The belief that animals so distinct as a monkey, an elephant, a 
humming-bird, a snake, a frog, and a fish, &c., could all have 
sprung from the same parents, will appear monstrous to those 
who have not attended to the recent progress of natural history. 
For this belief Implies the former existence of .links binding 
closely together all these forms, now so utterly unlike. 

Nevertheless, it is certain that groups of animals have existed, 
or do now exist, which serve to connect several of the great 
vertebrate classes more or less closely. We have seen that the 
Ornithorhynchus graduates towards reptiles; and Prof. Huxley 
has discovered, and is confirmed by Mr. Cope and others, that 
the Dinosaurians are in many important characters intermediate 
between certain reptiles and certain birds — the birds referred 
to being the ostrich-tribe (itself evidently a widely-diffused 
remnant of a larger group) and the Archeopteryx, that strange 
Secondary bird, with a long lizard-like tail. Again, according to 
Prof. Owen," the Ichthyosaurians — great sea-lizards furnished 
with paddles — present many affinities with fishes, or rather 
according to Huxley, with amphibians; a class which, including 
in its highest division frogs and toads, is plainly allied to the 
Ganoid fishes. These latter fishes swarmed during the earlier 
geological periods, and were constructed on what is called a 
generalized type, that is, they presented diversified affinities with 
other groups of organisms. The Lepidosiren is also so closely 
allied to amphibians and fishes, that naturalists long disputed in 
which of these two classes to rank it; it, and also some few 
Ganoid fishes, have been preserved from utter extinction by 
inhabiting rivers, which are harbors of refuge, and are related 
to the great waters of the ocean in the same way that islands 
are to continents. 

Lastly, one single member of the immense and diversified class 
of fishes, namely, the lancelet or amphioxus, is so different from 
all other fishes, that Hackel maintains that it ought to form a 
distinct class in the vertebrate kingdom. This fish is remarkable 
for its negative characters; it can hardly be said to possess a 
brain, vertebral column, or heart, &c.; so that it was classed by 

by Hackel, althoug-h he differs on some points. He expresses, also, 
his high estimate of the general tenor and spirit of the whole work. 
22 'Palaeontology,' 1860, p. 199. 



AFFINITIES AND GENEALOGY. 155 

the older naturalists amongst the worms. Many years ago Prof. 
Goodsir perceived that the lancelet presented some affinities with 
the Ascidians, which are invertebrate, hermaphrodite, marine 
creatures permanently attached to a support. They hardly ap- 
pear like animals, and consist of a simple, tough, leathery sack, 
with two small projecting orifices. They belong to the Mollus- 
coida of Huxley— a lower division of the great kingdom of the 
Mollusca; but they have recently been placed by some natural- 
ists amongst the Vermes or worms. Their larvae somewhat 
resemble tadpoles in shape,-^ and have the power of swimming 
freely about. M. Kovalevsky-* has lately observed that the larvae 
of Ascidians are related to the Vertebrata, in their manner of 
development, in the relative position of the nervous system, 
and in possessing a structure closely like the chorda dorsalis of 
vertebrate animals; and in this he has been since confirmed by 
Prof. Kupffer. M. Kovalevsky writes to me from Naples, that 
he has now carried these observations yet further; and should 
his results be well established, the whole will form a discovery 
of the very greatest value. Thus, if we may rely on embryology, 
ever the safest guide in classification, it seems that we have at 
last gained a clue to the source whence the Vertebrata were de- 
rived.^^ We should then be justified in believing that at an ex- 
tremely remote period a group of animals existed, resembling in 
many respects the larvae of our present Ascidians, which diverged 
into two great branches — the one retrograding in development 
and producing the present class of Ascidians, the other rising to 
the crown and summit of the animal kingdom by giving birth 
to the Vertebrata. 



23 At the Falkland Islands I had the satisfaction of seeing, in April, 
1833, and therefore some years before any other naturalist, the loco- 
motive larvae of a compound Ascidian, closely allied to Synoicum, 
but apparently generically distinct from it. The tail was about five 
times as long- as the oblong head, and terminated in a very fine fila- 
ment. It was, as sketched by me under a simple microscope plainly 
divided by transverse opaque partitions, which I presume represent 
the great cells figured by Kovalevsky. At an early stage of develop- 
ment the tail was closely coiled round the head of the larva. 

24 'Memoires de I'Acad. des Sciences de St. Petersbourg,' tom. x. 
No. 15, 1S66. 

25 But I am bound to add that some competent judges dispute this 
conclusion; for instance, M. Giard, in a series of papers in the Arch- 
ives de Zoologie Experimentale,' for 1872. Nevertheless, this natural- 
ist remarks, p. 281, "L'organisation de la larve ascidienne en dehors 
"de toute hypothese et de toute theorie, nous montre comment la 
"nature peut produire la disposition fondamentale du type vertebre 
"(I'existence d'une corde dorsale) chez un invertebre par la seule con- 
"dition vitale de I'ad.aptation, et cette simple possibilite du passage 
"supprime I'abime entre les deux sous-regnes, encore bien qu'en ignore 
"par ou le passage s'est fait en realite." 



156 THE DESCENT OF MAN. 

We have thus far endeavored rudely to trace the genealogy 
of the Vertebrata by the aid of their mutual affinities. We will 
now look to man as he exists; and we shall, I think, be able 
partially to restore the structure of our early progenitors, during 
successive periods, but not in due order of time. This can be 
effected by means of the rudiments which man still retains, by 
the characters which occasionally make their appearance in him 
through reversion, and by the aid of the principles of morphology 
and embryology. The various facts, to which I shall here allude, 
have been given in the previous chapters. 

The early progenitors of man must have been once covered 
with hair, both sexes having beards; their ears were probably 
pointed, and capable of movement; and their bodies were pro- 
vided with a tail, having the proper muscles. Their limbs and 
bodies were also acted on by many muscles which now only 
occasionally reappear, but are normally present in the Quadru- 
mana. At this or some earlier period, the great artery and nerve 
of the humerus ran through a supra-condyloid foramen. The 
intestine gave forth a much larger diverticulum or caecum than 
that now existing. The foot was then prehensile, judging from 
the condition of the great toe in the foetus; and our progenitors, 
no doubt, were arboreal in their habits, and frequented some 
warm, forest-clad land. The males had great canine teeth, which 
served them as formidable weapons. At a much earlier period 
the uterus was double; the excreta were voided through a cloaca; 
and the eye was protected by a third eyelid or nictitating mem- 
brane. At a still earlier period the progenitors of man must have 
been aquatic in their habits; for morphology plainly tells us that 
our lungs consist of a modified swim-bladder, which once served 
as a float. The clefts on the neck in the embryo of man show 
where the branchiae once existed. In the lunar or weekly re- 
current periods of some of our functions we apparently still retain 
traces of our primordial birthplace, a shore washed by the tides. 
At about this same early period the true kidneys were replaced 
by the corpora wolffiana. The heart existed as a simple pulsating 
vessel; and the chorda dorsalis took the place of a vertebral 
column. These early ancestors of man, thus seen in the dim 
recesses of time, must have been as simply, or even still more 
simply organized than the lancelet or amphioxus. 

There is one other point deserving a fuller notice. It has long 
been known that in the vertebrate kingdom one sex bears rudi- 
ments of various accessory parts, appertaining to the reproduc- 
tive system, which properly belong to the opposite sex; and it 
has now been ascertained that at a very early embryonic period 
both sexes possess true male and female glands. Hence some re- 
mote progenitor of the whole vertebrate kingdom appears to have 



AFFINITIES AND GENEALOGY. 157 

been hermaphrodite or androgynous.'^ But here we encounter 
a singular difficulty. In the mammalian class the males possess 
rudiments of a uterus with the adjacent passage, in their vesiculse 
prostaticse; they bear also rudiments of mammas, and some male 
Marsupials have traces of a marsupial sack.-' Other analogous 
facts could be added. Are we, then, to suppose that some ex-' 
tremely ancient mammal continued androgynous, after it had 
acquired the chief distinctions of its class, and therefore after it 
had diverged from the lower classes of the vertebrate kingdom? 
This seems very improbable, for we have to look to fishes, the 
lowest of all the classes, to find any still existent androgynous 
forms.'* That various accessory parts, proper to each sex, are 
found in a rudimentary condition in the opposite sex, may be 
explained by such organs having been gradually acquired by the 
one sex, and then transmitted in a more or less imperfect state 
to the other. When we treat of sexual selection, we shall meet 
with innumerable instances of this form of transmission, — as in 
the case of the spurs, plumes, and brilliant colors, acquired for 
battle or ornament hy male birds, and inherited by the females 
in an imperfect or rudimentary condition. 

The possession by male mammals of functionally imperfect 
mammary organs is, in some respects, especially curious. The 
Monotremata have the proper milk-secreting glands with orifices, 
but no nipples; and as these animals stand at the very base of 
the mammalian series, it is probable that the progenitors of 
the class also had milk-secreting glands, but no nipples. This 
conclusion is supported by what is known of their manner of 
development; for Professor Turner informs me, on the authority 

28 This is the conclusion of Prof. Gegenbaur, one of the highest au- 
thorities in comparative anatomy; see 'Grundzuge der vergleich. 
Anat.' 1870, s. 876. The result has been arrived at chiefly from the 
study of the Amphibia; but it appears from the researches of Wal- 
deyer (as quoted in 'Journal of Anat. and Phys.' 1869, p. 161), that the 
sexual organs of even "the higher vertebrata are, in their early ccndi- 
"tion, hermaphrodite." Similar views have long been held by some 
authors, though until recently without a firm basis. 

27 The male Thylacinus offers the best instance. Owen, 'Anatomy of 
Vertebrates,' vol. iii. p. 771. 

28 Hermaphroditism has been observed in several species of Serranus, 
as well as in some other fishes, where it is either normal and sym- 
metrical, or abnormal and unilateral. Dr. Zouteveen has given me ref- 
erences on this subject,more especially to a paper by Prof.Ralbertsma, 
in the 'Transact, of the Dutch Acad, of Sciences,' vol. xvi. Dr. Gun- 
ther doubts the fact, but it has now been recorded by too many good 
observers to be any longer disputed. Dr. M. Lessona writes to me, 
that he has verified the observations made by Cavolini on Serranus. 
Prof. Ercolani has recently shown ('Accad. delle Scienze,' Bologna, 
Dec. 28, 1871) that eels are androgynous. 



158 THE DESCENT OF MAN. 

of Kolliker and Langer, that in the embryo the mammary glands 
can be distinctly traced before the nipples are in the least 
visible; and the development of successive parts in the indi- 
vidual generally represents and accords with the development of 
successive beings in the same line of descent. The Marsupials 
differ from the Monotremata by possessing nipples; so that 
probably these organs were first acquired by the Marsupials, 
after they had diverged from, and risen above, the Monotremata, 
and were then transmitted to the placental mammals.-^ No one 
will suppose that the Marsupials still remained androgynous after 
they had approximately acquired their present structure. How 
then are we to account for male mammals possessing mammae? 
It is possible that they were first developed in the females and 
then transferred to the males; but from what follows this is 
hardly probable. 

It may be suggested, as another view, that long after the 
progenitors of the whole mammalian class had ceased to be 
androgynous, both sexes yielded milk, and thus nourished their 
young; and in the case of the Marsupials, that both sexes carried 
their young in marsupial sacks. This will not appear altogether 
improbable, if we reflect that the males of existing syngnathous 
fishes receive the eggs of the females in their abdominal pouches, 
hatch them, and afterwards, as some believe, nourish the 
young ;^° — that certain other male fishes hatch the eggs within 
their mouths or branchial cavities; — that certain male toads 
take the chaplets of eggs from the females, and wind them round 
their own thighs, keeping them there until the tadpoles are 
born; — that certain male birds undertake the whole duty of 
incubation, and that male pigeons, as well as the females, feed 
their nestlings with a secretion from their crops. But the above 
suggestion first occurred to me from the mammary glands of 
male mammals being so much more perfectly developed than 
the rudiments of the other accessory reproductive parts, which 
are found in the one sex though proper to the other. The mam- 

2» Prof. Gag-enbaur has shown ('Jenaische Zeitschrift,' Bd. vii. p. 212) 
that two distinct types of nipples prevail throughout the several mam- 
malian orders, but that it is quite intelligible how both could have 
been derived from the nipples of the Marsupials, and the latter from 
those of the Monotremata. See, also, a memoir by Dr. Huss, on 
the mammary glands ibid. B. viii. p. 176. 

^ Mr. Lockwood believes (as quoted in 'Quart. Journal of Science,' 
April, 1868, p. 269), from what he has observed of the development of 
Hippocampus, that the walls of the abdominal pouch of the male in 
some way afford nourishment. On male fishes hatching the ova in 
their mouths, see a very interesting paper by Prof. Wyman, in 'Proc. 
Boston Soc. of Nat. Hist.' Sept. 15, 1857; also Prof. Turner, in 'Journal 
of Anat. and Phys.' Nov. 1, 1866, p. 78. Dr. Gunther has likewise de- 
scribed similar cases. 



APFINITIES AND GENEALOGY. 159 

mary glands and nipples, as they exist in male mammals, can 
indeed hardly be called rudimentary; they are merely not fully 
developed, and not functionally active. They are sympathetically 
affected under the influence of certain diseases, like the same 
organs in the female. They often secrete a few drops of milk at 
birth and at puberty: this latter fact occurred in the curious 
case, before referred to, where a young man possessed two pairs 
of mammse. In man and some other male mammals these organs 
have been known occasionally to become so well developed dur- 
ing maturity as to yield a fair supply of milk. Now if we sup- 
pose that during a former prolonged period male mammals aided 
the females in nursing their offspring,-^ and that afterwards from 
some cause (as from the production of a smaller number of 
young) the males ceased to give this aid, disuse of the organs 
during maturity would lead to their becoming inactive; and 
from two well-known principles of inheritance, this state of 
inactivity would probably be transmitted to the males at the 
corresponding age of maturity. But at an earlier age these or- 
gans would be left unaffected, so, that they would be almost 
equally well developed in the young of both sexes. 

Conclusion. — Von Baer has defined advancement or progress in 
the organic scale better than any one else, as resting on the 
amount of differentiation and specialization of the several parts 
of a being, — when arrived at maturity; as I should be inclined to 
add. Now as organisms have become slowly adapted to diver- 
sified lines of life by means of natural selection, their parts will 
have become more and more differentiated and specialized for 
various functions, from the advantage gained by the division of 
physiological labor. The same part appears often to have been 
modified first for one purpose, and then long afterwards for some 
other and quite distinct purpose; and thus all the parts are 
rendered more and more complex. But each organism still re- 
tains the general type of structure of the progenitor from which 
it was aboriginally derived. In accordance with this view it 
seems, if we turn to geological evidence, that organization on 
the whole has advanced throughout the world by slow and in- 
terrupted steps. In the great kingdom of the Vertebrata it has 
culminated in man. It must not, however, be supposed that 
groups of organic beings are always supplanted, and disappear 
as soon as they have given birth to other and more perfect 
groups. The latter, though victorious over their predecessors, 
may not have become better adapted for all places in the economy 
of nature. Some old forms appear to have survived from inhab- 



31 Madlle. C. Royer has suggested a similar view in her 'Origine de 
I'Homme,' &c., 1870. 



160 THE DESCENT OF MAN. 

iting protected sites, where they have not been exposed to very 
severe competition; and these often aid us in constructing our 
genealogies, by giving us a fair idea of former and lost popula- 
tions. But we must not fall into the error of looking at the exist- 
ing members of any lowly-organized group as perfect representa- 
tives of their ancient predecessors. 

The most ancient progenitors in the kingdom of the Vertebrata, 
at which we are able to obtain an obscure glance, apparently 
consisted of a group of marine animals,^- resembling the larvae of 
existing Ascidians. These animals probably gave rise to a group 
of fishes, as lowly organized as the lancelet; and from these 
the Ganoids, and other fishes like the Lepidosiren, must have 
been developed. From such fish a very small advance would 
carry us on to the Amphibians. We have seen that birds and 
reptiles were once intimately connected together; and the Mono- 
tremata now connect mammals with reptiles in a slight degree. 
But no one can at present say by what line of descent the three 
higher and related classes, namely, mammals, birds, and reptiles,, 
were derived from the two lower vertebrate classes, namely, 
amphibians and fishes. In the class of mammals the steps are 
not difficult to conceive which led from the ancient Monotremata 
to the ancient Marsupials; and from these to the early progeni- 



es The inhabitants of the seashore must be greatly affected by the 
tides; animals living- either about the mean high-water mark, or 
about the mean low-water mark, pass through a complete cycle of 
tidal changes in a fortnight. Consequently, their food supply will un- 
dergo marked changes week by week. The vital functions of such 
animals, living under these conditions for many generations, can 
hardly fail to run their course in regular weekly periods. Now it is 
a mysterious fact that in the higher and now terrestrial Vertebrata, 
as well as in other classes, many normal and abnormal processes have 
one or more whole weeks as their periods; this would be rendered 
intelligible if the Vertebrata are descended from an animal allied to 
the existing tidal Ascidians. Many instances of such periodic proc- 
esses might be given, as the gestation of mammals, the duration of 
fevers, &c. The hatching of eggs affords also a good example, for, 
according to Mr. Bartlett ('Land and Water,' Jan. 7, 1871), the eggs 
of the pigeon are hatched in two weeks; those of the fowl in three; 
those of the duck in four; those of the goose in five; and those of the 
ostrich in seven weeks. As far as we can judge, a recurrent period, 
if approximately of the right duration for any process or function, 
would not, when once gained, be liable to change; consequently it 
might be thus transmitted through almost any number of generations. 
But if the function changed, the period would have to change, and 
would be apt to change almost abruptly by a whole week. This con- 
clusion, if sound, is highly remarkable; for the period of gestation in 
each mammal, and the hatching of each bird's eggs, and many other 
vital processes, thus betray to us the primordial birth-place of these 
animals. 



AFFINITIES AND GENEALOGY. 161 

tors of the placental mammals. We may thus ascend to the Le- 
murid^; and the interval is not very wide from these to the 
Simiadae. The Simiadse then branched off into two great stems, 
the New World and Old World monkeys; and from the latter, 
at a remote period, Man, the wonder and glory of the Universe, 
proceeded. .^ 

Thus we have given to man a pedigree of prodigious length, hut J. 
not, it may be said, of noble quality. The world, it has ofteir*' 
been remarked, appears as if it had long been preparing for the 
advent of man: and this, in one sense is strictly true, for he 
owes his birth to a long line of progenitors. If any single link 
in this chain had never existed, man would not have been exactly 
what he now is. Unless we wilfully close our eyes, we may, with 
our present knowledge, approximately recognize our parentage; 
nor need we feel ashamed of it. The most humble organism is 
something much higher than the inorganic dust under our feet; 
and no one with an unbiased mind can study any living creature, 
however humble, without being struck with enthusiasm at its 
marvelous structure and properties. 



162 THE DESCENT OP MAN. 



CHAPTER VII. 
ON THE RACES OF MAN. 

The nature and value of specific characters— Application to the races 
of man— Arguments in favor of, and opposed to, ranking the so- 
called races of man as distinct species— Sub-species— Monogenists 
and polygenists—Convergence of character— Numerous points of 
resemblance in body and mind between the most distinct races of 
man— The state of man when he first spread over the earth — Each 
race not descended from a single pair — The extinction of races — 
The formation of races — The efCects of crossing— Slight influence 
of the direct action of the conditions of life— Slight or no influence 
of natural selection— Sexual selection. 

It is not my intention here to describe the several so-called 
races of men; but I am about to inquire what is the value of the 
differences between them under a classificatory point of view, 
and how they have originated. In determining whether two or 
more allied forms ought to be ranked as species or varieties, 
naturalists are practically guided by the following considera- 
tions; namely, the amount of difference between them, and 
whether such differences relate to few or many points of struc- 
ture, and whether they are of physiological importance; but 
more especially whether they are constant. Constancy of char- 
acter is what is chiefly valued and sought for by naturalists. 
Whenever it can be shown, or rendered probable, that the forms 
in question have remained distinct for a long period, this be- 
comes an argument of much weight in favor of treating them as 
species. Even a slight degree of sterility between any two forms 
when first crossed, or in their offspring, is generally considered 
as a decisive test of their specific distinctness; and their con- 
tinued persistence without blending within the same area, is 
usually accepted as sufficient evidence, either of some degree of 
mutual sterility, or in the case of animals of some mutual repug- 
nance to pairing. 

Independently of fusion from intercrossing, the complete ab- 
sence, in a well-investigated region, of varieties linking together 
any two closely-allied forms, is probably the most important of 
all the criterions of their specific distinctness; and this is a some* 



THE RACES OF MAN. 

what different consideration from mere constancy of character, 
for two forms may be highly variable and yet not yield inter- 
mediate varieties. Geographical distribution is often brought 
into play unconsciously and sometimes consciously; so that 
forms living in two widely separated areas, in which most of the 
other inhabitants are specifically distinct, are themselves usually 
looked at as distinct; but in truth this affords no aid in dis- 
tinguishing geographical races from so-called good or true species. 

Now let us apply these generally-admitted principles to the 
races of man, viewing him in the same spirit as a naturalist would 
any other animal. In regard to the amount of difference between 
the races, we must make some allowance for cur nice powers of 
discrimination gained by the long habit of observing ourselves. 
In India, as Elphinstone remarks, although a newly-arrived Eu- 
ropean cannot at first distinguish the various native races, yet 
they soon appear to him extremely dissimilar;^ and the Hindoo 
cannot at first perceive any difference between the several Eu- 
ropean nations. Even the most distinct races of man are much 
more like each other in form than would at first be supposed; 
certain negro tribes must be excepted, whilst others, as Dr. Rohlfs 
writes to me, and as I have myself seen, have Caucasian 
features. This general similarity is well shown by the French 
photographs in the Collection Anthropologique du Museum de 
Paris of the men belonging to various races, the greater number 
of which might pass for Europeans, as many persons to whom 
I have shown them have remarked. Nevertheless, these men, if 
seen alive, would undoubtedly appear very distinct, so that we 
are clearly much influenced in our judgment by the mere color 
of the skin and hair, by slight differences in the features, and 
by expression. 

There is, however, no doubt that the various races, when care- 
fully compared and measured, differ much from each other, — as 
in the texture of the hair, the relative proportions of all parts 
of the body,^ the capacity of the lungs, the form and capacity of 
the skull, and even in the convolutions of the brain." But it 
would be an endless task to specify the numerous points of dif- 
ference. The races differ also in constitution, in acclimatization 

1 'History of India,' 1841, vol. i. p. 323. Father Ripa makes exactly 
the same remark with respect to the Chinese. 

2 A vast number of measurements of Whites, Blacks, and Indians, 
are given in the 'Investigations in the Militai-y and Anthropolog. Sta- 
tistics of American Soldiers,' by B. A. Gould, 1869, pp. 298-358; 'On the 
capacity of the lungs,' p. 471. See, also, the numerous and valuable 
tables, by Dr. Weisbach, from the observations of Dr. Scherzer and 
Dr. Schwarz, in the 'Reise der Novara: Anthropolog. Theil,' 1867. 

2 See, for instance, Mr. Marshall's account of the brain of a Bush- 
womaii in 'PhiL Transact.' 1864, p. 519. 



164 THE DESCENT OF MAN. 

and In liability to certain diseases. Their mental cliaracteristies 
are likewise very distinct; chiefly as it would appear in their 
emotional, but partly in their intellectual faculties. Every one 
who has had the opportunity of comparison, must have been 
struck with the contrast between the taciturn, even morose, 
aborigines of S, America and the light-hearted, talkative negroes. 
There is a nearly similar contrast between the Malays and the 
Papuans,* who live under the same physical conditions, and are 
separated from each other only by a narrow space of sea. 

We will first consider the arguments which may be advanced 
in favor of classing the races of man as distinct species, and 
then the arguments on the other side. If a naturalist, who had 
never before seen a Negro, Hottentot, Australian, or Mongolian, 
were to compare them, he would at once perceive that they 
differed in a multitude of characters, some of slight and some of 
considerable importance. On inquiry he would find that they 
were adapted to live under widely different climates, and that 
they differed somewhat in bodily constitution and mental dis- 
position. If he were then told that hundreds of similar specimens 
could be brought from the same countries, he would assuredly 
declare that they were as good species as many to which he had 
been in the habit of afiixing specific names. This conclusion 
would be greatly strengthened as soon as he had ascertained that 
these forms had all retained the same character for many cen- 
turies; and that negroes, apparently identical with existing 
negroes, had lived at least 4000 years ago.^ He would also hear, 
on the authority of an excellent observer. Dr. Lund,^ that the 



* Wallace, 'The Malay Archipelago,' vol. ii. 1869, p. 178. 

5 With respect to the figures in the famous Egyptian caves of Abou- 
Simbel, M. Pouchet says ('The Plurality of the Human Races,' Eng-. 
translat. 1864, p. 50), that he was far from finding recognizable repre- 
sentations of the dozen or more nations which some authors believ© 
that they can recognize. Even some of the most strongly-marked' 
races cannot be identified with that degree of unanimity which might 
have been expected from what has been written on the subject. Thus 
Messrs. Nott and Gliddon ('Types of Mankind,' p. 148) state that 
Rameses II., or the Great, has features superbly European; whereas 
Knox, another firm believer in the specific distinctness of the races 
of man ('Races of Man,' 1850, p. 201), speaking of young Memnon (the 
same as Rameses II., as I am informed by Mr. Birch), insists in the 
strongest manner that he is identical in character with the Jews of 
Antwerp. Again, when I looked at the statute of Amunoph III., I 
agreed with two officers of the establishment, both competent judges, 
that he had a strongly marked negro type of features; but Messrs. 
Nott and Gliddon (ibid. p. 146, fig. 53) describe him as a hybrid but 
not of "negro intermixture." 

« As quoted by Nott and Gliddon, 'Types of Mankind,' 1854, p. 439. 
They give also corroborative evidence; trtit C, .VTijgt tMnks that tiiQ 
S'ubj'ect I'e^q'uir^ fHirthtedr ia«vfegtige*ion. 



TKE RACES OF MAN. 165 

human skulls found in the caves of Brazil, entombed with many- 
extinct mammals, belonged to the same type as that now pre- 
vailing throughout the American Continent. 

Our naturalist would then perhaps turn to geographical dis- 
tribution, and he would probablj'- declare that those forms must 
be distinct species, which differ not only in appearance, but 
are fitted for hot, as well as damp or dry countries, and for the 
Arctic regions. He might appeal to the fact that no species in 
the group next to man, namely the Quadrumana, can resist a low 
temperature, or any considerable change of climate; and that 
the species which come nearest to man have never been reared 
to maturity, even under the temperate climate of Europe. He 
would be deeply impressed with the fact, first noticed by Agassiz,'' 
that the different races of man are distributed over the world in 
the same zoological provinces, as those inhabited by undoubtedly 
distinct species and genera of mammals. This is manifestly the 
case with the Australian, Mongolian, and Negro races of man; in 
a less well-marked manner with the Hottentots; but plainly with 
the Papuans and Malays, who are separated, as Mr. Wallace has 
shown, by nearly the same line which divides the great Malayan 
and Australian zoological provinces. The Aborigines of America 
range throughout the Continent; and this at first appears op- 
posed to the above rule, for most of the productions of the South- 
ern and Northern halves differ widely: yet some few living forms, 
as the opossum, range from the one into the other, as did formerly 
some of the gigantic Edentata. The Esquimaux, like other Arctic 
animals, extend round the whole polar regions. It should be 
observed that the amount of difference between the mammals of 
the several zoological provinces does not correspond with the 
degree of separation between the latter; so that it can hardly be 
considered as an anomaly that the Negro differs more, and the 
American much less from the other races of man, than do the 
mammals of the African and American continents from the mam- 
mals of the other provinces. Man, it may be added, does not 
appear to have aboriginally inhabited any oceanic island; and in 
this respect he resembles the other members of his class. 

In determining whether the supposed varieties of the same 
kind of domestic animal should be ranked as such, or as specifical- 
ly distinct, that is, whether any of them are descended from 
distinct wild species, every naturalist would lay much stress on 
the fact of their external parasites being specifically distinct. 
All the m-ore stress would be laid on this fact, as it would be an 
exceptional one; for I am informed by Mr. Denny that the most 
different kinds of dogs, fowls, and pigeons, in England, are in- 



7 'Diversits' cf .Origrki of this Human Races,' in thte "^Ghristia^ Ex- 

12 



16g THE DESCENT OF MAN. 

fested by the same species of Pediculi or lice. Now Mr. A. 
Murray lias carefully examined the Pediculi collected in different 
countries from the different races of man;^ and he finds that 
they differ, not only in color, but in the structure of their claws 
and limbs. In every case in which many specimens were obtained 
the differences were constant. The surgeon of a whaling ship 
in the Pacific assured me that wh^n the Pediculi, with which 
some Sandwich Islanders on board swarmed, strayed on to the 
bodies of the English sailors, they died in the course of three 
or four days. These Pediculi were darker colored, and appeared 
different from those proper to the natives of Chiloe in South 
America, of which he gave me specimens. These, again, appeared 
larger and much softer than European lice. Mr. Murray pro- 
cured four kinds from Africa, namely from the Negroes of the 
Eastern and Western coasts, from the Hottentots and Kafiirs; 
two kinds from the natives of Australia; two from North and 
two from South America. In these latter cases it may be pre- 
sumed that the Pediculi came from natives inhabiting different 
districts. With insects slight structural differences, if constant, 
are generally esteemed of specific value: and the fact of the 
races of man being infested by parasites, which appear to be 
specifically distinct, might fairly be urged as an argument that 
the races themselves ought to be classed as distinct species. 

Our supposed naturalist having proceeded thus far in his In- 
vestigation, would next inquire whether the races of men, when 
crossed, were in any degree sterile. He might consult the work" 
of Professor Broca, a cautious and philosophical observer, and in 
this he would find good evidence that some races were quite fertile 
together, but evidence of an opposite nature in regard to other 
races. Thus it has been asserted that the native women of Aus- 
tralia and Tasmania rarely produce children to European men; 
the evidence, however, on this head has now been shown to be 
almost valueless. The half-castes are killed by the pure blacks: 
and an account has lately been published of eleven half-caste 
youths murdered and burnt at the same time, whose remains 
were found by the police.^" Again, it has often been said that 
when mulattoes intermarry they produce few children; on the 

8 'Transact. R. Soc. of Edinburgh,' vol. xxii. 1861, p. 567. 

» 'On the Phenomena of Hybridity in the Genus Homo,' Eng-. translat. 
1864. 

1° See the interesting letter by Mr. T. A. Murray, in the 'Anthropolog. 
Review,' April, 1868 p. liii. In this letter Count Strzelecki's statement, 
that Australian women who have borne children to a white man are 
afterwards sterile with their own race, is disproved. M. A. de Qua' 
trefages has also collected ('Revue des Cours Scientifiques,' March, 
1869,. p. 239) much evidence that Australians and Europeans are not 
sterile when crossed. 



THE RACES OF MAN. 167 

other hand, Dr. Bachman of Charleston" positively asserts that 
he has known mulatto families which have intermarried for sev- 
eral generations, and have continued on an average as fertile as 
either pure whites or pure blacks. Inquiries formerly made by 
Sir C. Lyell on this subject led him, as he informs me, to the 
same conciusion.^^ In the United States the census for the year 
1854 included, according to Dr. Bachman, 405,751 mulattoes; and 
this number, considering all the circumstances of the case, seems 
small; but it may partly be accounted for by the degraded and 
anomalous position of the class, and by the profligacy of the 
women. A certain amount of absorption of mulattoes into ne- 
groes must always be in progress; and this would lead to an 
apparent diminution of the former. The inferior vitality of 
mulattoes is spoken of in a trustworthy work^^ as a well-known 
phenomenon; and this, although a different consideration from 
their lessened fertility, may perhaps be advanced as a proof of the 
specific distinctness of the parent races. No doubt both animal 
and vegetable hybrids, when produced from extremely distinct 
species, are liable to premature death; but the parents of mulat- 
toes cannot be put under the category of extremely distinct spe- 
cies. The common Mule, so notorious for long life and vigor, 
and yet so sterile, shows how little necessary connection there is 
in hybrids between lessened fertility and vitality; other analogous 
cases could be cited. 

Even if it should hereafter be proved that all the races of men 
were perfectly fertile together, he who was inclined from other 
reasons to rank them as distinct species, might with justice argue 
that fertility and sterility are not safe criterions of specific dis- 
tinctness. We know that these qualities are easily affected by 
changed conditions of life, or by close inter-breeding, and that 
they are governed by highly complex laws, for instance, that of 
the unequal fertility of converse crosses between the same two 
species. With forms which must be ranked as undoubted species, 
a perfect series exists from those which are absolutely sterile 
when crossed, to those which are almost or completely fertile. 

" 'An Examination of Prof. Agassiz's Sketch of the Nat. Provinces 
of the Animal World/ Charleston, 1855, p. 44. 

12 Dr. Rohlfs writes to me that he found the mixed races in the Great 
Sahara, derived from Arabs, Berbers, and Neg-roes of three tribes, 
extraordinarily fertile. On the other hand, Mr. Winwood Reade in- 
forms me that the Negroes on the Gold Coast, though admiring white 
men and mulattoes, have a maxim that mulattoes should not inter- 
marry, as the children are few and sickly. This belief, as Mr. Reade 
remarks, deserves attention, as white men have visited and resided 
on the Gold Coast for four hundred years, so that the natives have had 
ample time to gain knowledge through experience. 

13 'Military and Anthropolog." Statistics of Amejican Soldiers,' by 
B. A. Gould, 1S69, p. 319. 



168 THE DESCENT OP MAN. 

The degrees of sterility do not coincide strictly with the degrees 
of difference between the parents in external structure or habits 
of life. Man in many respects may be compared with those ani- 
mals which have long been domesticated, and a large body of 
evidence can be advanced in favor of the Pallasian doctrine,^^ 
that domestication tends to eliminate the sterility which is so 
general a result of the crossing of species in a state of nature. 
From these several considerations, it may be justly urged that 
the perfect fertility of the intercrossed races of man, if estab- 
lished, would not absolutely preclude us from ranking them as 
distinct species. 

Independently of fertility, the characters presented by the off- 
spring from a cross have been thought to indicate whether or not 
the parent-forms ought to be ranked as species or varieties; but 
after carefully studying the evidence, I have come to the con- 
clusion that no general rules of this kind can be trusted. The 

" 'The Variation of Animals and Plants under Domestication,' vol. ii. 
p. 109. I may here remind the reader that the sterility of species 
when crossed is not a specially-acquired quality, but, like the inca- 
pacity of certain trees to be grafted tog-ether, is incidental on oth«r 
acquired differences. The nature of these differences is unknown, 
but they relate more especially to the reproductive system, and much 
less so to external structure or to ordinary differences in constitution. 
One important element in the sterility of crossed species apparently 
lies in one or both having been long habituated to fixed conditions; 
for we know that changed conditions have a special influence on the 
reproductive system, and we have good reason to believe (as before 
remarked) that the fluctuating conditions of domestication tend to 
eliminate that sterility which is so general with species, in a natural 
state, when crossed. It has elsewhere been shown by me (ibid. vol. ii. 
p. 185, and 'Origin of Species' 5th edit., p. 317), that the sterility of 
crossed species has not been acquired through natural selection: we 
can see that when two forms have already been rendered very sterile, 
it is scarcely possible that their sterility should be augmented by the 
preservation or survival of the more and more sterile individuals; 
for as the sterility increases, fewer and fewer offspring will be pro- 
duced from which to breed, and at last only single individuals will 
be produced at the rarest intervals. But there is even a higher grade 
of sterility than this. Both Gartner and Kolreuter have proved that 
in genera of plants including many species, a series can be farmed 
from species which when crossed yield fewer and fewer seeds, to 
species which never produce a single seed, but yet are affected by the 
pollen of the other species as shown by the swelling of the germen. 
It is here manifestly impossible to select the more sterile individuals, 
which have already ceased to yield seeds; so that the acme of ster- 
ility, when the germen alone is affected cannot have been gained 
through selection. This acme, and no doubt the other grades of ster- 
ility, are the incidental results of certain unknown differences in the 
constitution oif the i^rbUuc'tiVe ^y^teto eft the ^jneoies W1a»icfh arfe 
cro'ss'ed. 



THE RACES OF MAN. 169 

ordinary result of a cross is the production of a blended or inter- 
mediate form; but in certain cases some of the oftspiing take 
closely after one parent-form, and some after the other. This is 
especially apt to occur when the parents differ in characters 
which first appeared as sudden variations or monstrosities.^^ I 
refer to this point, because Dr. Rohlfs informs me that he has 
frequently seen in Africa the offspring of negroes crossed with 
members of other races, either completely black or completely 
white, or rarely piebald. On the other hand, it is notorious that 
in America mulattoes commonly present an intermediate appear- 
ance. 

We have now seen that a naturalist might feel himself fully 
justified in ranking the races of man as distinct species; for he 
has found that they are distinguished by many differences in 
structure and constitution, some being of importance. These 
differences have, also, remained nearly constant for very long 
periods of time. Our naturalist will have been in some degree 
influenced by the enormous range of man, which is a great 
anomaly in the class of mammals, if mankind be viewed as a 
single species. He will have been struck with the distribution of 
the several so-called races, which accords with that of other 
undoubtedly distinct species of mammals. Finally, he might 
urge that the mutual fertility of all the races has not as yet been 
fully proved, and even if proved would not be an absolute proof 
of their specific identity. 

On the other side of the question, if our supposed naturalist 
were to inquire whether the forms of man keep distinct like 
ordinary species, when mingled together in large numbers in the 
same country, he would immediately discover that this was by 
no means the case. In Brazil he would behold an immense mon- 
grel population of Negroes and Portuguese; in Chiloe, and other 
parts of South America, he would behold the whole population 
consisting of Indians and Spaniards blended in various degrees." 
In many parts of the same continent he would meet with the 
most complex crosses between Negroes, Indians, and Europeans; 
and judging from the vegetable kingdom, such triple crosses 
afford the severest test of the mutual fertility of the parent-forms. 
In one island of the Pacific he would find a small population of 
mingled Polynesian and English blood; and in the Fiji Archi- 
pelago a population of Polynesian and Negritos crossed in all 
degrees. Many analogous cases could be added; for instance, in 



^^ 'The Variation of Animals,' &c., vol. ii. p. 92. 

18 M. de Quatrefages has given ('Anthropolog. Review,' Jan. 1869, p. 22) 
an interesting account of the success and energy of the Paulistas in 
Brazil, who are a much crossed race of Portuguese and Indians, with 
a mixture of the blood of other races. 



170 THE DESCENT OF MAN. 

Africa. Hence the races of man are not sufficiently distinct to 
inhabit the same country without fusion; and the absence of 
fusion affords the usual and best test of specific distinctness. 

Our naturalist would likewise be much disturbed as soon as 
he perceived that the distinctive characters of all the races were 
highly variable. This fact strikes every one on first beholding 
the negro slaves in Brazil, who have been imported from all 
parts of Africa. The same remark holds good with the Poly- 
nesians, and with many other races. It may be doubted whether 
any character can be named which is distinctive of a race and is 
constant. Savages, even within the limits of the same tribe, 
are not nearly so uniform in character, as has been often as- 
serted. Hottentot women offer certain peculiarities, more strongly 
marked than those occurring in any other race, but these are 
known not to be of constant occurrence. In the several American 
tribes, color and hairiness differ considerably; as does color to a 
certain degree, and the shape of the features greatly in the 
Negroes of Africa. The shape of the skull varies much in some 
races ; ^' and so it is with every other character. Now all natural- 
ists have learnt by dearly-bought experience, how rash it is to 
attempt to define species by the aid of inconstant characters. 

But the most weighty of all the arguments against treating 
the races of man as distinct species, is that they graduate into 
each other, independently in many cases, as far as we can judge, 
of their having intercrossed. Man has been studied more carefully 
than any other animal, and yet there is the greatest possible 
diversity amongst capable judges whether he should be classed as 
a single species or race, or as two (Virey), as three (Jacquinot), 
as four (Kant), five (Blumenbach), six (Buff on), seven (Hunter), 
eight (Agassiz), eleven (Pickering), fifteen (Bory St. Vincent), 
sixteen (Desmoulins), twenty-two (Morton), sixty (Crawford), or 
as sixty-three, according to Burke.^^ This diversity of judgment 
does not prove that the races ought not to be ranked as species, 
but it shows that they graduate into each other, and that it is 
hardly possible to discover clear distinctive characters between 
them. 

Every naturalist who has had the misfortune to undertake the 
description of a group of highly varying organisms, has en- 
countered cases (I speak after experience) precisely like that of 

" For instance with the aborigines of America and Australia. Prof. 
Huxley says ('Transact. Internat. Congress of Prehist. Arch.* 1868, 
p. 105) that the skulls of many South Germans and Swiss are "as 
"short and as broad as those of the Tartars," «&c. 

18 See a good discussion on this subject in Waitz, 'Introduct. to An- 
thropology,' Eng. translat. 1863, pp. 19S-20S, 227. I have taken some of 
the above statements from H. Tuttle's 'Origin and Antiquity of Physi- 
cal Man,' Boston, 1866, p. 35. 



THE RACES OF MAN. 171 

man, and if of a cautious disposition, he will end by uniting all 
the forms which graduate into each other, under a single species; 
for he will say to himself that he has no right to give names to 
objects which he cannot define. Cases of this kind occur in the 
Order which includes man, namely in certain genera of monkeys; 
whilst in other genera, as in Cercopithecus, most of the species 
can be determined with certainty. In the American genus Cebus, 
the various forms are ranked by some naturalists as species, by 
others as mere geographical races. Now if numerous specimens 
of Cebus were collected from all parts of South America, and 
those forms which at present appear to be specifically distinct, 
were found to graduate into each other by close steps, they 
would usually be ranked as mere varieties or races; and this 
course has been followed by most naturalists with respect to the 
races of man. Nevertheless, it must be confessed that there are 
forms, at least in the vegetable kingdom," which we cannot avoid 
naming as species, but which are connected together by num- 
berless gradations, independently of intercrossing. 

Some naturalists have lately employed the term "sub-species'* 
to designate forms which possess many of the characteristics of 
true species, but which hardly deserve so high a rank. Now if 
we refiect on the weighty arguments above given, for raising the 
races of man to the dignity of species, and the insuperable diffi- 
culties on the other side in defining them, it seems that the term 
"sub-species" might here be used with propriety. But from 
long habit the term "race" will perhaps always be employed. 
The choice of terms is only so far important in that it is desirable 
to use, as far as possible, the same terms for the same degrees of 
difference. Unfortunately this can rarely be done: for the larger 
genera generally include closely-allied forms, which can be dis- 
tinguished only with much difficulty, whilst the smaller genera 
within the same family include forms that are perfectly distinct; 
yet all must be ranked equally as species. So again, species 
within the same large genus by no means resemble each other to 
the same degree: on the contrary, some of them can generally 
be arranged in little groups round other species like satellites 
round planets.^" 

The question whether mankind consists of one or several spe- 
cies has of late years been much discussed by anthropologists, 
who are divided into the two schools of monogenists and poly- 
genists. Those who do not admit the principle of evolution, must 

1® Prof. Nageli has carefully described several striking cases in his 
'Botanische Mittheilungen/ B. ii. 186b", s. 294-369. Prof. Asa Gray has 
made analogous remarks on some intermediate forms in the Com- 
positae of N. America. 

20 'Origin of Species,' 5th edit. p. 68. 



172 THE DESCENT OF MAN. 

look at species as separate creations, or as in some manner 
as distinct entities; and they must decide what forms of man 
they will consider as species by the analogy of the method com- 
monly pursued in ranking other organic beings as species. But it 
is a hopeless endeavor to decide this point, until some definition 
of the term "species" is generally accepted; and the definition 
must not include an indeterminate element such as an act of 
creation. We might as well attempt without any definition to 
decide whether a certain number of houses should be called a 
village, town, or city. We have a practical illustration of the 
difficulty in the never-ending doubts whether many closely allied 
mammals, birds, insects, and plants, which represent each other 
respectively in North America and Europe, should be ranked as 
species or geographical races; and the like holds true of the pro- 
ductions of many islands situated at some little distance from the 
nearest continent. 

Those naturalists, on the other hand, who admit the principle 
of evolution, and this is now admitted by the majority of rising 
men, will feel no doubt that all the races of man are descended 
from a single primitive stock; whether or not they may think 
fit to designate the races as distinct species, for the sake of ex- 
pressing their amount of difference.-^ With our domestic ani- 
mals the question whether the various races have arisen from 
one or more species is somewhat different. Although it may be 
admitted that all the races, as well as all the natural species 
within the same genus, have sprung from the same primitive 
stock, yet it is a fit subject for discussion, whether all the do- 
mestic races of the dog, for instance, having acquired their present 
amount of difference since some one species was first domesticated 
by man; or whether they owe some of their characters to in- 
heritance from distinct species, which had already been differen- 
tiated in a state of nature. With man no such question can arise, 
for he cannot be said to have been domesticated at any particular 
period. 

During an early stage in the divergence of the races of man 
from a common stock, the differences between the races and 
their number must have been small; consequently as far as 
their distinguishing characters are concerned, they then had less 
claim to rank as distinct species than the existing so-called races. 
Nevertheless, so arbitrary is the term of species, that such early 
races would perhaps have been ranked by some naturalists as 
distinct species, if their differences, although extremely slight, 
had been more constant than they are at present, and had not 
graduated into each other. 

21 See Prof. Huxley to this effect in the 'Fortnightly Review,' 1865, p. 
275. 



THE RACES OF MAN. 173 

It is however possible, though far more probable, that the 
early progenitors of man might formerly have diverged much in 
character, until they became more unlike each other than any 
now existing races; but that subsequently, as suggested by 
Vogt,^- they converged in character. When man selects the off- 
spring of two distinct species for the same object, he sometimes 
induces a considerable amount of convergence, as far as general 
appearance is concerned. This is the case, as shown by Von Nath- 
usius,"^ with the improved breeds of the pig, which are descend- 
ed from two distinct species; and in a less marked manner with 
the improved breeds of cattle. A great anatomist, Gratiolet, 
maintains that the anthropomorphous apes do not form a natural 
sub-group; but that the orang is a highly developed gibbon or 
semnopithecus, the chimpanzee a highly developed macacus, and 
the gorilla a highly developed mandrill. If this conclusion, 
which rests almost exclusively on brain-characters, be admitted, 
we should have a case of convergence at least in external char- 
acters, for the anthropomorphous apes are certainly more like 
each other in many points, than they are to other apes. All 
analogical resemblances, as of a whale to a fish, may indeed be 
said to be cases of convergence; but this term has never been ap- 
plied to superficial and adaptive resemblances. It would, how- 
ever, be extremely rash to attribute to convergence close similar- 
ity of character in many points of structure amongst the modified 
descendants of widely distinct beings. The form of 'a crystal is 
determined solely by the molecular forces, and it is not surprising 
that dissimilar substances should sometimes assume the same 
form; but with organic beings we should bear in mind that the 
form of each depends on an infinity of complex relations, namely 
on variations, due to causes far too intricate to be followed, — 
on the nature of the variations preserved, these depending on the 
physical conditions, and still more on the surrounding organisms 
which compete with each, — and lastly, on inheritance (in itself a 
fluctuating element) from innumerable progenitors, all of which 
have had their forms determined through equally complex rela- 
tions. It appears incredible that the modified descendants of two 
organisms, if these differed from each other in a marked manner, 
should ever afterwards converge so closely as to lead to a near 
approach to identity throughout their whole organization In 
the case of the convergent races of pigs above referred to, evi- 
dence of their descent from two primitive stocks is, according to 
Von Nathusius, still plainly retained, in certain bones of their 

22 'Lectures on Man,' Eng-. translat. 1864, p. 468. 

2^ 'Die Racen des Schweines,' 1860, s. 46. 'Vorstudien fur Geschichte, 
&c., Schweineschadel,' 1864, s. 10^. With respect to cattle, see M. de 
Quatrefages, 'Unite de I'Espece Humaine,' 1861, p. 119. 



174 THE DESCENT OF MAN. 

skulls. If the races of man had descended, as Is supposed by 
some naturalists, from two or more species, which differed from 
each other as much, or nearly as much, as does the orang from 
the gorilla, it can hardly be doubted that marked differences in 
the structure of certain bones would still be discoverable in man 
as he now exists. 



Although the existing races of man differ in many respects, as 
in color, hair, shape of skull, proportions of the body, &c., yet 
if their whole structure be taken into consideration they are 
found to resemble each other closely in a multitude of points. 
Many of these are so unimportant or of so singular a nature, 
that it is extremely improbable that they should have been inde- 
pendently acquired by aboriginally distinct species or races. The 
same remark holds good with equal or greater force with respect 
to the numerous points of mental similarity between the most 
distinct races of man. The American aborigines, Negroes and 
Europeans are as different from each other in mind as any three 
races that can be named; yet I was incessantly struck, whilst 
living with the Fuegians on board the "Beagle," with the many 
little traits of character, showing how similar their minds were 
to ours; and so it was with a full-blooded negro with whom I 
happened once to be intimate. 

He who will read Mr. Tylor's and Sir J. Lubbock's interesting 
works-* can hardly fail to be deeply impressed with the close 
similarity between the men of all races in tastes, dispositions and 
habits. This is shown by the pleasure which they all take in 
dancing, rude music, acting, painting, tattooing, and otherwise 
decorating themselves; in their mutual comprehension of ges- 
ture-language, by the same expression in their features, and by 
the same inarticulate cries, when excited by the same emotions. 
This similarity, or rather identity, is striking, when contrasted 
with the different expressions and cries made by distinct species 
of monkeys. There is good evidence that the art of shooting 
with bows and arrows has not been handed down from any 
common progenitor of mankind, yet as Westropp and Nilsson 
have remarked,-' the stone arrow-heads, brought from the most 
distant parts of the world, and manufactured at the most remote 
periods, are almost identical; and this fact can only be accounted 
for by the various races having similar inventive or mental 

21 Tylor's 'Early History of Mankind,* 1865; with respect to gesture- 
language, see p. 54. Lubbock's 'Prehistoric Times,' 2nd edit. 1869. 

25 'On Analogous Forms of Implements,' in 'Memoirs of Anthropolog. 
Soc.,' by H. M. Westropp. 'The Primitive Inhabitants of Scandi- 
navia,' Eng. translat. edited by Sir J. Lubbock, 1868, p. 104. 



THE RACES OF MAN. 175 

powers. The same observation has been made by archgeologists" 
with respect to certain widely-prevalent ornaments, such as zig- 
zags, &c.; and with respect to various simple beliefs and cus- 
toms, such as the burying of the dead under megaiithic struc- 
tures. I remember observing in South America,-' that there, as 
in so many other parts of the world, men have generally chosen 
the summits of lofty hills, to throw up piles of stones, either as 
a record of some remarkable event, or for burying their dead. 

Now when naturalists observe a close agreement in numerous 
small details of habits, tastes, and dispositions between two or 
more domestic races, or between nearly-allied natural forms, 
they use this fact as an argument that they are descended from a 
common progenitor who was thus endowed; and consequently 
that all should be classed under the same species. The same 
argument may be applied with much force to the races of man. 

As it is improbable that the numerous and unimportant points 
of resemblance between the several races of man in bodily struc- 
ture and mental faculties (I do not here refer to similar customs) 
should all have been independently acquired, they must have 
been inherited from progenitors who had these same characters. 
We thus gain some insight into the early state of man, before he 
had spread step by step over the face of the earth. The spreading 
of man to regions widely separated by the sea, no doubt, pre- 
ceded any great amount of divergence of character in the several 
races; for otherwise we .should sometimes meet with the same 
race in distinct continents; and this is never the case. Sir J. 
Lubbock, after comparing the arts now practiced by savages iu 
all parts of the world, specifies those which man could not have 
known, when he first wandered from his original birthplace; 
for if once learnt they would never have been forgotten.^^ He 
thus shows that "the spear, which is but a development of the 
"knife-point, and the club, which is but a long hammer, are the 
"only things left." He admits, however, that the art of making 
fire probably had been already discovered, for it is common to 
all the races now existing, and was known to the ancient cave- 
inhabitants of Europe. Perhaps the art of making rude canoes 
or rafts was likewise known; but as man existed at a remote 
epoch, when the land in many places stood at a very different 
level to what it does now, he would have been able, without the 
aid of canoes, to have spread widely. Sir J. Lubbock further 
remarks how improbable it is that our earliest ancestors could 
have "counted as high as ten, considering that so many races 

26 Westropp, 'On Cromlechs,* &c., 'Journal of Ethnological Soc' as 
given in 'Scientific Opinion,' June 2nd, 1869, p. 3. 
^ 'Journal of Researches: Voyage of the "Beagle," ' p. 46. 
28 'Prehistoric Times,' 1869, p. 574. 



170 THE DESCENT OF MAN. 

"now in existence cannot get beyond four." Nevertheless, at 
this early period, the intellectual and social faculties of man 
could hardly have been inferior in any extreme degree to those 
possessed at present by the lowest savages; otherwise primeval 
man could not have been so eminently successful in the struggle 
for life, as proved by his early and wide diffusion. 

From the fundamental differences between certain languages, 
some philologists have inferred that when man first became 
widely diffused, he was not a speaking animal; but it may be 
suspected that languages, far less perfect than any now spoken, 
aided by gestures, might have been used, and yet have left no 
traces on subsequent and more highly-developed tongues. With- 
out the use of some language, however imperfect, it appears 
doubtful whether man's intellect could have risen to the standard 
implied by his dominant position at an early period. 

Whether primeval man, when he possessed but few arts, and 
those of the rudest kind, and when his power of language was 
extremely imperfect, would have deserved to be called man, must 
depend on the definition which we employ. In a series of forms 
graduating insensibly from some ape-like creature to man as he 
now exists, it would be impossible to fix on any definite point 
when the term "man" ought to be used. But this is a matter of 
very little importance. So again, it is almost a matter of indif- 
ference whether the so-called races of man are thus designated, 
or are ranked as species or sub-species; but the latter term ap- 
pears the more appropriate. Finally, we may conclude that when 
the principle of evolution is generally accepted, as it surely will 
be before long, the dispute between the monogenists and the 
polygenists will die a silent and unobserved death. 

One other question ought not to be passed over without notice, 
namely, whether, as is sometimes assumed, each sub-species or 
race of man has sprung from a single pair of progenitors. With 
our domestic animals a new race can readily be formed by care- 
fully matching the varying offspring from a single pair, or even 
from a single individual possessing some new character; but 
most of our races have been formed, not intentionally from a 
selected pair, but unconsciously by the preservation of many in- 
dividuals which have varied, however slightly, in some useful or 
desired manner. If in one country stronger and heavier horses, 
and in another country lighter and fleeter ones, were habitually 
preferred, we may feel sure that two distinct sub-breeds would 
be produced in the course of time, without any one pair having 
been separated and bred from, in either country. Many races 
have been thus formed, and their manner of formation is closely 
analogous to that of natural species. We know, also, that the 
horses taken to the Falkland Islands have, during successive 



THE EXTINCTION OF RACES. 177 

generations, become smaller and weaker, whilst those which have 
run wild on the Pampas have acquired larger and coarser heads; 
and such changes are manifestly due, not to any one pair, but to 
{ill the individuals having been subjected to the same conditions, 
aided, perhaps, by the principle of reversion. The new sub- 
breeds in such cases are not descended from any single pair, but 
from many individuals which have varied in different degrees, 
but in the same general manner; and we may conclude that the 
races of man have been similarly produced, the modifications 
being either the direct result of exposure to different conditions, 
or the indirect result of some form of selection. But to this 
latter subject we shall presently return. 

On the Exti7iction of the Races of Man. — The partial or com- 
plete extinction of many races and sub-races of man is historically 
known. Humboldt saw in South America a parrot which was 
the sole living creature that could speak a word of the language 
of a lost tribe. Ancient monuments and stone implements found 
in all parts of the world, about which no tradition has been 
preserved by the present inhabitants, indicate much extinction. 
Some small and broken tribes, remnants of former races, still 
survive in isolated and generally mountainous districts. In 
Europe the ancient races were all, according to Schaaffhausen,^ 
"lower in the scale than the rudest living savages;" they must 
therefore have differed, to a certain extent, from any existing 
race. The remains described by Professor Broca from Les Eyzies, 
though they unfortunately appear to have belonged to a single 
family, indicate a race with a most singular combination of low 
or simious, and of high characteristics. This race is "entirely 
"different from any other, ancient or modern, that we have ever 
"heard of."''' It differed, therefore, from the quaternary race of 
the caverns of Belgium. 

Man can long resist conditions which appear extremely un- 
favorable for his existence.^^ He has long lived in the extreme 
regions of the "North, with no wood for his canoes or imple- 
ments, and with only blubber as fuel, and melted snow as drink. 
In the southern extremity of America the Fuegians survive with- 
out the protection of clothes, or of any building worthy to be 
called a hovel. In South Africa the aborigines wander over arid 
plains, where dangerous beasts abound. Man can withstand the 
deadly influence of the Terai at the foot of the Himalaya, and 
the pestilential shores of tropical Africa. 

2» Translation in 'Anthropolog-ical Review,' Oct. 1868, p. 431. 

^ 'Transact. Internal. Congress of Prehistoric Arch,' 1S68, pp. 172-175. 
See also Broca (translation) in 'Anthropolog-ical Review,' Oct. 1868, p. 
410. 

^ Dr. Gerland 'Ueber das Aussterben der Naturvolker,' 1868, s. 82. 
1? 



178 THE DESCENT OF MAN. 

Extinction follows chiefly from the competition of tribe with 
tribe, and race with race. Various checks are always in action, 
serving to keep dov/n the numbers of each savage tribe, — such 
as periodical famines, nomadic habits and the consequent deaths 
of infants, prolonged suckling, wars, accidents, sickness, licen- 
tiousness, the stealing of women, infanticide, and especially les- 
sened fertility. If any one of these checks increases in power, 
even slightly, the tribe thus affected tends to decrease; and 
when of two adjoining tribes one becomes less numerous and less 
powerful than the other, the contest is soon settled by war, 
slaughter, cannibalism, slavery, and absorption. Even when a 
weaker tribe is not thus abruptly swept away, if it once begins 
to decrease, it generally goes on decreasing until it becomes 
extinct.^- 
~f When civilized nations come into contact with barbarians the 
V struggle is short, except where a deadly climate gives its aid to 
the native race. Of the causes which lead to the victory of 
civilized nations, some are plain and simple, others complex and 
obscure. We can see that the cultivation of the land will be 
fatal in many ways to savages, for they cannot, or will not, 
change their habits. New diseases and vices have in some cases 
proved highly destructive; and it appears that a new disease 
often causes much death, until those who are most susceptible 
to its destructive influence are gradually weeded out;^ and so it 
may be with the evil effects from spirituous liquors, as well as 
with the unconquerably strong taste for them shown by so many 
savages. It further appears, mysterious as is the fact, that the 
first meeting of distinct and separated people generates disease.^* 
Mr. Sproat, who in Vancouver Island closely attended to the 
subject of extinction, believed that changed habits of life, conse- 
quent on the advent of Europeans, induces much ill health. He 
lays, also, great stress on the apparently trifling cause that the 
natives become "bewildered and dull by the new life around them; 
"they lose the motives for exertion, and get no new ones in their 
"place."^^ 

The grade of their civilization seems to be a most important 
element in the success of competing nations, A few centuries 
ago Europe feared the inroads of Eastern barbarians; now any 
such fear w^ould be ridiculous. It is a more curious fact, as Mr. 

32 Gerland (ibid. s. 12) gives facts in support of this statement. 

^ See remarks to this effect in Sir H. Holland's 'Medical Notes and 
Reflections,' 1839, p. 390. 

3* I have collected ('Journal of Researches, Voyag-e of the "Beagle," ' 
p. 435) a good many cases bearing on this subject: see also Gerland, 
ibid. s. 8. Poeppig speaks of the "breath of civilization as poisonous 
*'to savages." 

^ Sproat, 'Scenes and Studies of Savage Life,' 1868, p. 284. 



THE EXTINCTION OF RACES. 179 

Bagehot has remarked, that savages did not formerly waste away 
before the classical nations, as they now do before modern civil- 
ized nations; had they done so, the old moralists would have 
mused over the event; but there is no lament in any writer of 
that period over the perishing barbarians.^® The most potent of 
all the causes of extinction, appears in many cases to be lessened 
fertility and ill-health, especially amongst the children, arising 
from changed conditions of life, notwithstanding that the nev/ 
conditions may not be injurious in themselves. I am much in- 
debted to Mr. H. H. Howorth for having called my attention to 
this subject, and for having given me information respecting it. 
I have collected the following cases. 

When Tasmania was first colonized the natives were roughly 
estimated by some at 7000 and by others at 20,000. Their number 
was soon greatly reduced, chiefly by fighting with the English 
and with each other. After the famous hunt by all the colonists, 
when the remaining natives delivered themselves up to the gov- 
ernment, they consisted only of 120 individuals,^" who were in 1832 
transported to Flinders Island. This island, situated between 
Tasmania and Australia, is forty miles long, and from twelve to 
eighteen miles broad: it seems healthy, and the natives were 
well treated. Nevertheless, they suffered greatly in health. In 
1834 they consisted (Bonwick, p. 250) of forty-seven adult males, 
forty-eight adult females, and sixteen children, or in all of 111 
souls. In 1835 only one hundred were left. As they continued 
rapidly to decrease, and as they themselves thought that they 
should not perish so quickly elsewhere, they were removed in 
1847 to Oyster Cove in the southern part of Tasmania. They then 
consisted (Dec. 20th, 1847) of fourteen men, twenty-two women 
and ten children. ^^ But the change of site did no good. Disease 
and death still pursued them, and in 1864 one man (who died in 
1869), and three elderly women alone survived. The infertility 
of the w^omen is even a more remarkable fact than the liability 
of all to ill-health and death. At the time when only nine women 
were left at Oyster Cove, they told Mr. Bonwick (p. 386), that only 
two had ever borne children: and these two had together pro- 
duced only three children! 

With respect to the cause of this extraordinary state of things, 
Dr. Story remarks that death followed the attempts to civilize 
the natives. "If left to themselves to roam as they were wont 
"and undisturbed, they would have reared more children, and 

38 Bagehot, 'Physics and Politics,' 'Fortnightly Review,' April 1, 1868, 
p. 455. 

37 All the statements here given are taken from 'The last of the Tas- 
manians,' by J. Bonwick, 1870. 

38 This is the statement of the Governor of Tasmania, Sir W. Deni- 
son, 'Varieties of Vice-Regal Life,' 1S70, vol. i. p. 67. 



180 THE DESCENT OF MAN. 

"there would have been less mortality." Another careful ob- 
server of the natives, Mr. Davis, remarks, "The births have been 
"few and the deaths numerous. This may have been in a great 
"measure owing to their change of living and food; but more so 
"to their banishment from the mainland of Van Diemen's Land, 
"and consequent depression of spirits" (Bonwick, pp. 388, 390). 

Similar facts have been observed in two widely difterent parts 
of Australia. The celebrated explorer, Mr. Gregory, told Mr. 
Bonwick, that in Queensland "the want of reproduction was be- 
"ing already felt with the blacks, even in the most recently settled 
"parts, and that decay would set in." Of thirteen aborigines from 
Shark's Bay who visited Murchison River, twelve died of con- 
sumption within three months.^^ 

The decrease of the Maories of New Zealand has been caj'efully 
investigated by Mr. Fenton, in an admirable report, from which 
all the following statements, with one exception, are taken.^" 
The decrease in number since 1830 is admitted by every one, in- 
cluding the natives themselves, and is still steadily progressing. 
Although it has hitherto been found impossible to take an actual 
census of the natives, their numbers were carefully estimated by 
residents in many districts. The result seems trustworthy, and 
shows that during the fourteen years, previous to 1858, the de- 
crease was 19.42 per cent. Some of the tribes, thus carefully 
examined, lived above a hundred miles apart, some on the coast, 
some inland; and their means of subsistence and habits differed 
to a certain extent (p. 28). The total number in 1858 was be- 
lieved to be 53,700, and in 1872, after a second interval of fourteen 
years, another census was taken, and the number is given as 
only 36,359, showing a decrease of 32.29 per cent.!^ Mr. Fenton, 
after showing in detail the insufficiency of the various causes, 
usually assigned in explanation of this extraordinary decrease, 
such as new diseases, the profligacy of the women, drunkenness, 
wars, &c., concludes on weighty grounds that it depends chiefly 
on the unproductiveness of the women, and on the extraordinary 
mortality of the young children (pp. 31, 34). In proof of this he 
shows (p. 33) that in 1844 there was one non-adult for every 
2.57 adults; whereas in 1858 there was only one non-adult for 
every 3.27 adults. The mortality of the adults is also great. He 
adduces as a further cause of the decrease the inequality of the 
sexes; for fewer females are born than males. To this latter 
point, depending perhaps on a widely distinct cause, I shall re- 
turn in a future chapter. Mr. Fenton contrasts with astonish- 
ment the decrease in New Zealand with the increase in Ireland; 



39 For these cases, see Bonwick's 'Daily Life of the Tasmanians,' 
1870, p. 90 and the 'Last of the Tasmanians,' 1870, p. 386. 

*o 'Observations on the Aboriginal Inhabitants of New Zealand,' pub- 
lished by the Government, 1859. 

*i 'New Zealand,' by Alex. Kennedy, 1873, p. 47. 



THE EXTINCTION OF RACES. 



countries not very dissimilar in climate, and where the inhabi- 
tants now follow nearly similar habits. The Maories themselves 
(p. 85) "attribute their decadence, in some measure, to the intro- 
"duction of new food and clothing, and the attendant change of 
"habits;" and it will be seen, when we consider the influence of 
changed conditions on fertility, that they are probably right. 
The diminution began between the years 1830 and 1840; and Mr. 
Fenton shows (p. 40) that about 1830, the art of manufacturing 
putrid corn (maize), by long steeping in water, was discovered 
and largely practiced; and this proves that a change of habits was 
beginning amongst the natives, even when New Zealand was only 
thinly inhabited by Europeans. When I visited the Bay of Is- 
lands in 1835, the dress and food of the inhabitants had already 
been much modified: they raised potatoes, maize, and other agri- 
cultural produce, and exchanged them for English manufactured 
goods and tobacco. 

It is evident from many statements in the life of Bishop Patte- 
son,*^ that the Melanesians of the New Hebrides and neighboring 
archipelagoes, suffered to an extraordinary degree in health, and 
perished in large numbers, when they were removed to New 
Zealand, Norfolk Island, and other salubrious places, in order to 
be educated as missionaries. 

The decrease of the native population of the Sandwich Islands 
is as notorious as that of New Zealand. It has been roughly 
estimated by those best capable of judging, that when Cook dis- 
covered the Islands in 1779, the population amounted to about 
300,000. According to a loose census in 1823, the numbers then 
were 142,050. In 1832, and at several subsequent periods, an ac- 
curate census was officially taken, but I have been able to obtain 
only the following returns: 



Year. 



Native Population. 

(Except during 1832 
and 1836, when the 
few foreigners in 
the islands were 
included). 



Annual rate of de- 
crease per cent., 
assuming it to 
have been uniform 
between the suc- 
cessive censuses ; 
these censuses be- 
ing taken at irreg- 
ular intervals. 



1832 
1836 
1853 
1860 
1866 
1872 



130.313 



108.579 i 

71,019 [ 

67,084 [ 

58,765 [ 

51,531 r 



4.46 
2.47 
0.81 
2.18 

i.n 



*2 'Life of J. C. Patteson,' by C. M. Younge, 1874; see more especially 
vol. i. p. 530. 
13 



182 THE DESCENT OF MAN. 

We here see that in the interval of forty years, between 1832 
and 1872, the population has decreased no less than sixty-eight 
per cent.! This has been attributed by most writers to the 
profligacy of the women, to former bloody wars, and to the severe 
labor imposed on conquered tribes and to newly introduced dis- 
eases, which have been on several occasions extremely destruc- 
tive. No doubt these and other such causes have been highly ef- 
ficient, and may account for the extraordinary rate of decrease 
between the years 1832 and 1836; but the most potent of all the 
causes seems to be lessened fertility. According to Dr. Ruschen- 
berger of the U. S. Navy, who visited these islands between 1835 
and 1837, in one district of Hawaii, only twenty-five men out of 
1134, and in another district only ten out of 637, had a family 
with as many as three children. Of eighty married women, only 
thirty-nine had ever borne children; and "the official report gives 
"an average of half a child to each married couple in the whole 
"island." This is almost exactly the same average as with the 
Tasmanians at Oyster Cove. Jarves, who published his History 
in 1843, says that "families who have three children are freed 
"from all taxes; those having more, are rewarded by gifts of land 
"and other encouragements." This unparalleled enactment by 
the government well shows how infertile the race had become. 
The Rev. A. Bishop stated in the Hawaiian 'Spectator' in 1839, that 
a large proportion of the children die at early ages, and Bishop 
Staley informs me that this is still the case, just as in New 
Zealand. This has been attributed to the neglect of the children 
by the women, but it is probably in large part due to innate 
weakness of constitution in the children, in relation to the les- 
sened fertility of their parents. There is, moreover, a further re- 
semblance to the case of New Zealand, in the fact that there is a 
large excess of male over female births: the census of 1872 gives 
31,650 males to 25,247 females of all ages, that is 125.36 males for 
every 100 females; whereas in all civilized countries the females 
exceed the males. No doubt the profligacy of the women may in 
part account for their small fertility; but their changed habits of 
life is a much more probable cause, and which will at the same 
time account for the increased mortality, especially of the chil- 
dren. The islands were visited by Cook in 1779, by Vancouver in 
1794, and often subsequently by whalers. In 1819 missionaries 
arrived, and found that idolatry had been already abolished, and 
other changes effected by the king. After this period there was 
a rapid change in almost all the habits of life of the natives, and 
they soon became "the most civilized of the Paciflc Islanders." 
One of my informants, Mr. Coan, who was born on the islands, 
remarks that the natives have undergone a greater change in 
their habits of life in the course of fifty years than Englishmen 
during a thousand years. From information received from 



THE EXTINCTION OF RACES. ISS 

Bishop Staley, it does not appear that the poorer classes have 
ever much changed their diet, although many new kinds of fruit 
have been introduced, and the sugar-cane is in universal use. 
Owing, however, to their passion for imitating Europeans, they 
altered their manner of dressing at an early period, and the use 
of alcoholic drinks became very general. Although these changes 
appear inconsiderable, I can well believe, from what is known 
with respect to animals, that they might suflBce to lessen the fer- 
tility of the natives.^ 

Lastly, Mr, Macnamara states^ that the low and degraded in- 
habitants of the Andaman Islands, on the eastern side of the Gulf 
of Bengal, are "eminently susceptible to any change of climate: 
"in fact, take them away from their island homes, and they are 
"almost certain to die, and that independently of diet or ex- 
"traneous influences." He further states that the inhabitants of 
the valley of Nepal, which is extremely hot in summer, and also 
the various hill-tribes of India, suffer from dysentery and fever 
when on the plains; and they die if they attempt to pass the 
whole year there. 

We thus see that many of the wilder races of man are apt to 
suffer much in health when subjected to changed conditions 
or habits of life, and not exclusively from being transported to 
a new climate. Mere alterations in habits, which do not appear 
injurious in themselves, seem to have this same effect; and in 
several cases the children are particularly liable to suffer. It 
has often been said, as Mr. Macnamara remarks, that man can 
resist with impunity the greatest diversities of climate and other 
changes; but this is true only of the civilized races. Man in 
his wild condition seems to be in this respect almost as sus- 
ceptible as his nearest allies, the anthropoid apes, which have 
never yet survived long, when removed from their native 
country. 

Lessened fertility from changed conditions, as in the case of 
the Tasmanians, Maories, Sandwich Islanders, and apparently 
the Australians, is still more interesting than their liability to 
ill-health and death; for even a slight degree of infertility com- 

*3 The foregoing statements are taken chiefly from the following 
works: 'Jarves' History of the Hawaiian Islands,' 1843, p. 400-407. 
Cheever, 'Life in the Sandwich Islands,' 1851, p. 277. Ruschenberger is 
quoted by Bonwick, 'Last of the Tasmanians,' 1870, p. 378. Bishop is 
quoted by Sir E. Belcher, 'Voyage Round the World,' 1843, vol. i., p. 
272. I owe the census of the several years to the kindness of Mr. Coan, 
at the request of Dr. Youmans of New York, and in most ca&es I have 
compared the Youmans figures with those given in several of the 
above-named works. I have omitted the census for 1850, as I have 
seen two widely different numbers given. 

^ 'The Indian Medical Gazette,' Nov. 1, 1871, p. 240. 



Ig4 THE DESCENT OP MAN. 

"bined with those other causes which tend to checl^ the increase 
of every population, would sooner or later lead to extinction. 
The diminution of fertility may be explained in some cases by 
the profligacy of the women (as until lately with the Tahitians) 
but Mr. Penton has shown that this explanation by no means suf- 
fices with the New Zealanders, nor does it with the Tasmanians. 

In the paper above quoted, Mr. Macnamara gives reasons for 
believing that the inhabitants of districts subject to malaria are 
apt to be sterile; but this cannot apply in several of the above 
cases. Some writers have suggested that the aborigines of is- 
lands have suffered in fertility and health from long continued 
inter-breeding; but in the above cases infertility has coincided 
too closely with the arrival of Europeans for us to admit this 
explanation. Nor have we at present any reason to believe 
that man is highly sensitive to the evil effects of inter-breeding, 
especially in areas so large as New Zealand, and the Sandwich 
archipelago with its diversified stations. On the contrary, it is 
known that the present inhabitants of Norfolk Island are nearly 
all cousins or near relations, as are the Todas in India, and the 
inhabitants of some of the Western Islands of Scotland; and yet 
they seem not to have suffered in fertility.^ 

A much more probable view is suggested by the analogy of the 
lower animals. The reproductive system can be shown to be sus- 
ceptible to an extraordinary degree (though why we know not) 
to changed conditions of life; and this susceptibility leads both 
to beneficial and to evil results. A large collection of facts on 
this subject is given in chap, xviii. of vol. ii. of my 'Variation of 
Animals and Plants under Domestication,' I can here give only 
the briefest abstract; and every one interested in the subject may 
consult the above work. Very slight changes increase the health, 
vigor and fertility of most or all organic beings, whilst other 
changes are known to render a large number of animals sterile. 
One of the most familiar cases, is that of tamed elephants, not 
breeding in India; though they often breed in Ava, where the 
females are allowed to roam about the forests to some extent, and 
are thus placed under more natural conditions. The case of 
various American monkeys, both sexes of which have been kept 
for many yekrs together in their own countries, and yet have 
very rarely or never bred, is a more apposite instance, because of 
their relationship to man. It is remarkable how slight a change 
in the conditions often induces sterility in a wil'd animal when 
eaptured; and this is the more strange as all our domesticated 

*^ On the close relationship of the Norfolk Islanders, see Sir W. 
Denison, 'Varieties of Vice-Regal Life,' vol. i. 1870, p. 410. For the 
Todas, see Col. Marshall's work, 1873, p. 110. For the Western Islands 
of Scotland, Dr. Mitchell, 'Edinburgh Medical Journal,' March to 
June, 1865. 



THE EXTINCTION OF RACES. 185 

animals have become more fertile than they were in a state of 
nature; and some of them can resist the most unnatural condi- 
tions with undiminished fertility.*^ Certain groups of animals 
are much more liable than others to be affected by captivity; 
and generally all the species of the same group are affected in 
the same manner. But sometimes a single species in a group 
is rendered sterile, whilst the others are not so; on the other 
hand, a single species may retain its fertility whilst most of the 
others fail to breed. The males and females of some species 
when confined, or when allowed to live almost, but not quite free, 
in their native country, never unite; others thus circumstanced 
frequently unite but never produce offspring; others again pro- 
duce some offspring, but fewer than in a state of nature; and 
as bearing on the above cases of man, it is important to remark 
that the young are apt to be weak and sickly, or malformed, and 
to perish at an early age. 

Seeing how general is this law of the susceptibility of the 
reproductive system to changed conditions of life, and that it 
holds good with our nearest allies, the Quadrumana, I can hardly 
doubt that it applies to man in his primeval state. Hence if 
savages of any race are induced suddenly to change their habits 
of life, they become more or less sterile, and their young off- 
spring suffer in health, in the same manner and from the same 
cause, as do the elephant and hunting-leopard in India, many 
monkeys in America, and a host of animals of all kinds, on re- 
moval from their natural conditions. 

We can see why it is that aborigines, who have long inhabited 
islands, and who must have been long exposed to nearly uniform 
conditions, should be specially affected by any change in their 
habits, as seems to be the case. Civilized races can certainly 
resist changes of all kinds far better than savages; and in this 
respect they resemble domesticated animals, for though the lat- 
ter sometimes suffer in health (for instance European dogs in 
India), yet they are rarely rendered sterile, though a few such 
instances have been recorded.*^ The immunity of civilized races 
and domesticated animals is probably due to their having been 
subjected to a greater extent, and therefore having grown some- 
what more accustomed, to diversified or varying conditions, than 
the majority of wild animals; and to their having formerly 
immigrated or been carried from country to country, and to dif- 
ferent families or sub-races having inter-crossed. It appears 
that a cross with civilized races at once gives to an aboriginal 
race an immunity from the evil consequences of changed condi- 



^ For the evidence on this head, see 'Variation of Animals,' &c., 
vol. ii. p. 111. 
*^ 'Variation of Animals,' &c., vol. ii., p. 16. 



186 THE DESCENT OP MAN. 

tions. Tlius tlie crossed offspring from the Tahitians and Eng- 
lish, when settled in Pitcairn Island, increased so rapidly that 
the island was soon overstocked; and in June 1856 they were re- 
moved to Norfolk Island. They then consisted of 60 married 
persons and 134 children, making a total of 194. Here they like- 
wise increased so rapidly, that although sixteen of them returned 
to Pitcairn Island in 1859, they numbered in January 1868, 300 
souls, the males and females being in exactly equal numbers. 
What a contrast does this case present with that of the Tas- 
manians; the Norfolk Islanders increased in only twelve and a 
half years from 194 to 300; whereas the Tasmanians decreased 
during fifteen years from 120 to 46, of which latter number only 
ten were children.*^ 

So again in the interval between the census of 1866 and 1872 
the natives of full blood in the Sandwich Islands decreased by 
8081, whilst the half-castes, who are believed to be healthier, in- 
creased by 847; but I do not know whether the latter number 
includes the offspring from the half-castes, or only the half- 
castes of the first generation. 

The cases which I have here given all relate to aborigines, 
who have been subjected to new conditions as the result of 
the immigration of civilized men. But sterility and ill-health 
would probably follow, if savages were compelled by any cause, 
such as the inroad of a conquering tribe, to desert their homes 
and to change their habits. It is an interesting circumstance 
that the chief check to wild animals becoming domesticated, 
which implies the power of their breeding freely when first cap- 
tured, and one chief check to wild men, when brought into con- 
tact with civilization, surviving to form a civilized race, is the 
same, namely, sterility from changed conditions of life. 

Finally, although the gradual decrease and ultimate extinc- 
tion of the races of man is a highly complex problem, depending 
on many causes which differ in different places and at different 
times; it is the same problem as that presented by the extinc- 
tion of one of the higher animals — of the fossil horse, for in- 
stance, which disappeared from South America, soon afterwards 
to be replaced, within the same districts, by countless troops 
of the Spanish horse. The New Zealander seems conscious of 
this parallelism, for he compares his future fate with that of 
the native rat now almost exterminated by the European rat. 
Though the difficulty is great to our imagination, and really 
great, if we wish to ascertain the precise causes and their man- 

*8 These details are taken from 'The Mutineers of the "Bounty," ' 
by Lady Belcher, 1870; and from 'Pitcairn Island,' ordered to be 
printed by the House of Commons, May 29th, 1863. The following- 
statements about the Sandwich Islanders are from the 'Honolulu Ga- 
zette,' and from M>. Coan. 



THE FORMATION OF RACES. 187 

ner of action, it ought not to be so to our reason, as long as we 
keep steadily in mind that the increase of each species and each 
race is constantly checked in various ways; so that if any new 
check, even a slight one, be superadded, the race will surely de- 
crease in number; and decreasing numbers will sooner or later 
lead to extinction; the end, in most cases, being promptly deter- 
mined by the inroads of 'conquering tribes. 

On the Formation of the Races of Man. — In some cases the 
crossing of distinct races has led to the formation of a new race. 
The singular fact that Europeans and Hindoos, who belong to 
the same Aryan stock, and speak a language fundamentally the 
same, differ widely in appearance, whilst Europeans differ but 
little from Jews, who belong to the Semitic stock, and speak 
quite another language, has been accounted for by Broca,*^ 
through certain Aryan branches having been largely crossed by 
indigenous tribes during their wide diffusion. When two races 
in close contact cross, the first result is a heterogeneous mixture: 
thus Mr. Hunter, in describing the Santali or hill-tribes of India, 
says that hundreds of imperceptible gradations may be traced 
"from the black, squat tribes of the mountains to the tall olive- 
"colored Brahman, with his intellectual brow, calm eyes, and 
"high but narrow head;" so that it is necessary in courts of 
justice to ask the witnesses whether they are Santalis or Hin- 
doos.^" Whether a heterogeneous people, such as the inhabit- 
ants of some of the Polynesian Islands, formed by the crossing 
of two distinct races, with few or no pure members left, would 
ever become homogeneous, is not known from direct evidence. 
But as with our domesticated animals, a cross-breed can cer- 
tainly be fixed and made uniform by careful selection^^ in the 
course of a few generations, we may infer that the free inter- 
crossing of a heterogeneous mixture during a long descent would 
supply the place of selection, and overcome any tendency to 
reversion; so that the crossed race would ultimately become 
homogeneous, though it might not partake in an equal degree 
of the characters of the two parent-races. 

Of all the differences between the races of man, the color of 
the skin is the most conspicuous and one of the best marked. It 
was formerly thought that differences of this kind could be 
accounted for by long exposure to different climates; but Pal- 
las first showed that this is not tenable, and he has since been 



^ 'On Anthropology,' translation 'Anthropolog-. Review,' Jan. 1868, 
p. 38. 

5" 'The Annals of Rural Bengal,' 1868 p. 134. 

^^ 'The Variation of Animals and Plants under Domestication,' vol. ii. 
p. 95. 



188 THE DESCENT OF MAN. 

followed by almost all anthropologists.^^ This view has been 
rejected chiefly because the distribution of the variously col- 
ored races, most of whom must have long inhabited their present 
homes, does not coincide with corresponding differences of cli- 
mate. Some little weight may be given to such cases as that of 
the Dutch families, who, as we hear on excellent authority.^" 
have not undergone the least change of color after residing for 
three centuries in South Africa. An argument on the same side 
may likewise be drawn from the uniform appearance in various 
parts of the world of gipsies and Jews, though the uniformity of 
the latter has been somewhat exaggerated.^* A very damp or a 
very dry atmosphere has been supposed to be more influential in 
modifying the color of the skin than mere heat; but as D'Or- 
bigny in South America, and Livingstone in Africa, arrived at 
diametrically opposite conclusions with respect to dampness and 
dryness, any conclusion on this head must be considered as very 
doubtful.'" 

Various facts, which I have given elsewhere, prove that the 
color of the skin and hair is sometimes correlated in a surpris- 
ing manner with a complete immunity from the action of certain 
vegetable poisons, and from the attacks of certain parasites. 
Hence it occurred to me, that negroes and other dark races 
might have acquired their dark tints by the darker Individuals 
escaping from the deadly influence of the miasma of their native 
countries, during a long series of generations. 

I afterwards found that this same idea had long ago occurred 
to Dr. Wells.'° It has long been known that negroes, and even 
mulattoes, are almost completely exempt from the yellow fever, 
so destructive in tropical America." They likewise escape to a 
large extent the fatal intermittent fevers, that prevail along at 
least 2600 miles of the shores of Africa, and which annually 
cause one-fifth of the white settlers to die, and another fifth to 



52 Pallas, 'Act. Acad. St. Petersburg,' 1780, part ii. p. 69. He was fol- 
lowed by Hudolphi, in his 'Beytrage zur Anthropologie,' 1812. An ex- 
cellent summary of the evidence is given by Godron, 'De I'Espece,' 
1859, vol. ii. p. 246, &c. 

53 Sir Andrew Smith, as quoted by Knox, 'Races of Man,' 1850, p. 473. 
^* See De Quatrefages on this head, 'Revue des Cours Scientifiques,' 

Oct. 17, 1868, p. 731. 

^5 Livingstone's 'Travels and Researches in S. Africa,' 1857, pp. 338, 
329. D'Orbigny, as quoted by Godron, 'De I'Espece,' vol. ii. p. 266. 

58 See a paper read before the Royal Soc. in 1813, and published in 
his Essays in 1818. I have given an account of Dr. Wells' views in 
the Historical Sketch (p. xvi.) to my 'Origin of Species.' Various 
cases of color correlated with constitutional peculiarities are given in 
my 'Variation of Animals under Domestication,' vol. ii. pp. 227, 335. 

57 See, for instance, Nott and Gliddon, 'Types of Mankind,' p. 68. 



THE FORMATION OF RACES. 189 

return liome inralided/^ This immunity in the negro seems to 
be partly inherent, depending on some unknown peculiarity of 
constitution, and partly the result of acclimatization. Pouchet'* 
states that the negro regiments recruited near the Soudan, and 
borrowed from the Viceroy of Egypt for the Mexican war, 
escaped the yellow-fever almost equally v/ith the negroes origin- 
ally brought from various parts of Africa and accustomed to the 
climate of the "West Indies. That acclimatization plays a part, 
is shown by the many cases in which negroes have become some- 
what liable to tropical fevers, after having resided for some time 
in a colder climate.'''^ The nature of the climate under which the 
white races have long resided, likewise has some influence on 
them; for during the fearful epidemic of yellow-fever in Dem- 
erara during 1837, Dr. Blair found that the death-rate of the 
immigrants was proportional to the latitude of the country 
whence they had come. With the negro the immunity, as far as 
it is the result of acclimatization, implies exposure during a 
prodigious length of time; for the aborigines of tropical America 
who have resided there from time immemorial, are not exempt 
from yellow fever; and the Rev. H. B. Tristram states, that there 
are districts in Northern Africa which the native inhabitants are 
compelled annually to leave, though the negroes can remain with 
safety. 

That the immunity of the negro is in any degree correlated 
with the color of his skin is a mere conjecture: it may be cor- 
related with some difference in his blood, nervous system, or 
other tissues. Nevertheless, from the facts above alluded to, and 
from some connection apparently existing between complexion 
and a tendency to consumption, the conjecture seemed to me not 
improbable. Consequently I endeavored, with but little success,®^ 

58 Major Tulloch, in a paper read before the Statistical Society, 
April 20th, 1840, and given in the 'Athenaeum,' 1840, p. 353. 

59 'The Plurahty of the Human Race,' (translat.), 1864, p. 60. 

60 Quatrefages, 'Unite de I'Espece Humaine,' 1861, p. 205. Waltz, 
'Introduct. to Anthropology,' translat. vol. i. 1883, p. 124. Livingstone 
gives analogous cases in his 'Travels.' 

51 In the spring of 1862 I obtained permission from the Director-Gen- 
eral of the Medical department of the Army, to transmit to the sur- 
geons of the various regiments on foreign service a blank table, with 
the following appended remarks, but I have received no returns. "As 
"several well-marked cases have been recorded with our domestic 
"animals of a relation between the color of the dermal appendages 
"and the constitution; and it being notorious that there is some lim- 
"ited degree of relation between the color of the races of man and 
"the climate inhabited by them; the following investigation seems 
"worth consideration. Namely, whether there is any relation in Eu- 
"ropeans between the color of their hair, and their liability to the dis- 
"eases of tropical countries. If the surgeons of the several regi- 



190 THE DESCENT OF MAN. 

to ascertain how far it holds good. The late Dr. Daniell, who 
had long lived on the West Coast of Africa, told me that he did 
not believe in any such relation. He was himself unusually fair, 
and had withstood the climate in a wonderful manner. When 
he first arrived as a boy on the coast, an old and experienced 
negro chief predicted from his appearance that this would prove 
the case. Dr. Nicholson, of Antigua, after having attended to this 
subject, writes to me that he does not think that dark-colored Eu- 
ropeans escape the yellow-fever more than those that are light- 
colored. Mr. J. M. Harris altogether denies that Europeans with 
dark hair withstand a hot climate better than other men: on the 
contrary, experience has taught him in making a selection of 
men for service on the coast of Africa, to choose those with red 
hair."- As far, therefore, as these slight indications go, there 
seems no foundation for the hypothesis, that blackness has re- 
sulted from the darker and darker individuals having survived 
better during long exposure to fever-generating miasma. 

Dr. Sharpe remarks,^ that a tropical sun, which burns and 
blisters a white skin, does not injure a black one at all; and, as 
he adds, this is not due to habit in the individual, for children 
only six or eight months old are often carried about naked, and 
are not affected. I have been assured by a medical man, that 

"ments, when stationed in unhealthy tropical districts, would be so 
"good as first to count, as a standard of comparison, how many men, 
"in the force whence the sick are drawn, have dark and light- 
"colored hair, and hair of intermediate or doubtful tints; and if a 
"similar account were kept by the same medical gentlemen, of all 
"the men who suffered from malarious and yellow fevers, or from 
"dysentery, it would soon be apparent, after some thousand cases had 
"been tabulated, whether there exists any relation between the color 
"of the hair and constitutional liability to tropical diseases. Per- 
"haps no such relation would be discovered, but the investigation is 
"well worth making. In case any positive result were obtained, it 
"might be of some practical use in selecting men for any particular 
"service. Theoretically the result would be of high interest, as indl- 
"cating one means by which a race of men inhabiting from a remote 
"period an unhealthy tropical climate, might have become dark-col- 
"ored by the better preservation of dark-haired or dark-complexioned 
"individuals during a long succession of generations." 

"2 'Anthropological Review,' Jan. 1866, p. xxi. Dr. Sharpe also says 
with respect to India ('Man a Special Creation,' 1873, p. 118), that "it 
"has been noticed by some medical officers that Europeans with light 
"hair and florid complexions suffer less from diseases of tropical 
"countries than persons with dark hair and sallow complexions; 
"and, so far as I know, there appear to be good grounds for this 
"remark." On the other hand, Mr. Heddle, of Sierra Leone, "who 
"has had more clerks killed under him than any other man," by the 
climate of the West African Coast (W. Reade, 'African Sketch Book,' 
vol. ii. p. 522), holds a directly opposite view, as does Capt. Burton. 

«3 'Man a Special Creation,' 1873, p. 119. 



THE FORMATION OF RACES. 191 

some years ago during each summer, but not during the winter, 
his hands became marked with light brown patches, like, al- 
though larger that freckles, and that these patches were never 
affected by sun-burning, whilst the white parts of his skin have 
on several occasions been much inflamed and blistered. With 
the lower animals there is, also, a constitutional difference in lia- 
bility to the action of the sun between those parts of the skin 
clothed with white hair and other parts.°^ Whether the saving 
of the skin from being thus burnt is of sufficient importance to 
account for a dark tint having been gradually acquired by man 
through natural selection, I am unable to judge. If it be so, we 
should have to assume that the natives of tropical America have 
lived there for a much shorter time than the negroes in Africa, 
or the Papuans in the southern parts of the Malay archipelago, 
just as the lighter-colored Hindoos have resided in India for a 
shorter time than the darker aborigines of the central and south- 
ern parts of the peninsula. 

Although with our present knowledge we cannot account for 
the differences of color in the races of man, through any advan- 
tage thus gained, or from the direct action of climate; yet we 
must not quite ignore the latter agency, for there is good reason 
to believe that some inherited effect is thus produced.^^ 

We have seen in the second chapter that the conditions of life 
affect the development of the bodily frame in a direct manner, 
and that the effects are transmitted. Thus, as is generally ad- 
mitted, the European settlers in the United States undergo a 
slight but extraordinarily rapid change of appearance. Their 
bodies and limbs become elongated; and I hear from Col. Bernys 
that during the late war in the United States, good evidence was 
afforded of this fact by the ridiculous appearance presented by 
the German regiments, when dressed in ready-made clothes 
manufactured for the American market, and which were much 
too long for the men in every way. There is, also, a considerable 
body of evidence showing that in the Southern States the house- 
slaves of the third generation present a markedly different ap- 
pearance from the field-slaves.^® 

^ 'Variation of Animals and Plants under Domestication,' vol. 11. 
pp. 336, 337. 

^5 See, for instance, Quatrefages ('Revue des Cours Scientifiques,' 
Oct. 10, 1868, p. 724) on the effects of residence in Abyssinia and Arabia, 
and other analogous cases. Dr. Rolle ('Der Mensch, seine Abstam- 
mung,' &c., 1865, s. 99) states, on the authority of Khanikof, that the 
greater number of German families settled in Georgia, have acquired 
in the course of two generations dark hair and eyes. Mr. D. Forbes 
informs me that the Quichaus in the Andes vary greatly in color, 
according to the position of the valleys inhabited by them. 

88 Harlan, 'Medical Researches,' p. 532. Quatrefages ('Unite de I'Es- 
pece Humaine.' 1861, p. 128) has collected much evidence on this head. 



192 THE DESCENT OF MAN. 

If, however, we look to the races of man as distributed over the 
world, we must infer that their characteristic differences cannot 
be accounted for by the direct action of different conditions of 
life, even after exposure to them for an enormous period of time. 
The Esquimaux live exclusiv^ely on animal food; they are 
clothed in thick fur, and are exposed to intense cold and to pro- 
longed darkness; yet they do not differ in any extreme degree 
from the inhabitants of Southern China, who live entirely on 
vegetable food, and are exposed almost naked to a hot, glaring 
climate. The unclothed Fuegians live on the marine productions 
of their inhospitable shores; the Botocudos of Brazil wander 
about the hot forests of the interior and live chiefly on vegetable 
productions; yet these tribes resemble each other so closely that 
the Fuegians on board the "Beagle" were mistaken by some Bra- 
zilians for Botocudos. The Botocudos again, as well as the other 
inhabitants of tropical America, are wholly different from the 
Negroes who inhabit the opposite shores of the Atlantic, a,re ex- 
posed to a nearly similar climate, and follow nearly the same 
habits of life. 

Nor can the differences between the races of man be accounted 
for by the inherited effects of the increased or decreased use of 
parts, except to a quite insignificant degree. Men who habitu- 
ally live in canoes, may have their legs somewhat stunted; those 
who inhabit lofty regions may have their chests enlarged; and 
those who constantly use certain sense-organs may have the 
cavities in which they are lodged somewhat increased in size, and 
their features consequently a little modified. With civilized na- 
tions, the reduced size of the jaws from lessened use — the habit- 
ual play of different muscles serving to express different emo- 
tions—and the increased size of the brain from greater intellect- 
ual activity, have together produced a considerable effect on 
their general appearance when compared with savages.®^ In- 
creased bodily stature, without any corresponding increase in 
the size of the brain, may (judging from the previously adduced 
case of rabbits), have given to some races an elongated skull of 
the dolichocephalic type. 

Lastly, the little-understood principle of correlated develop- 
ment has sometimes come into action, as in the case of great 
muscular development and strongly projecting supra-orbital 
ridges. The color of the skin and hair are plainly correlated, as 
is the texture of the hair with its color in the Mandans of North 
America.*^^ The color also of the skin, and the odor emitted by it, 

07 See Prof. Schaaffhausen, translat. in 'Anthropological Review,' 
Oct. 1868, p. 429. 

63 Mr. Catlin states ('N. American Indians,' 3rd edit. 1842, vol. i. p. 49) 
that in the whole trihe of the Mandans, about one in ten or twelve 
of the members, of all ages and both sexes, have bright silvery gray 



THE FORMATION OF RACES. 193 

are likewise in some manner connected. With the breeds of sheep 
the number of hairs within a given space and the number of the 
excretory pores are related.^^ If we may judge from the analogy 
of our domesticated animals, many modifications of structure in 
man probably come under this principle of correlated develop- 
ment. 

We have now seen that the external characteristic differences 
between the races of man cannot be accounted for in a satisfac- 
tory manner by the direct action of the conditions of life, nor by 
the effects of the continued use of parts, nor through the prin- 
ciple of correlation. We are therefore led to inquire whether 
slight individual differences, to which man is eminently liable, 
may not have been preserved and augmented during a long series 
of generations through natural selection. But here we are at 
once met by the objection that beneficial variations alone can be 
thus preserved; and as far as we are enabled to judge, although 
always liable to err on this head, none of the differences between 
the races of man are of any direct or special service to him. The 
intellectual and moral or social faculties must of course be ex- 
cepted from this remark. The great variability of all the ex- 
ternal differences between the races of man, likewise indicates 
that they cannot be of much importance; for if important, they 
would long ago have been either fixed and preserved, or elimi- 
nated. In this respect man resembles those forms, called by 
naturalists protean or polymorphic, which have remained ex- 
tremely variable, ov/ing, as it seems, to such variations being of 
an indifferent nature, and to their having thus escaped the ac- 
tion of natural selection. 

We have thus far been baffled in all our attempts to account 
for the differences between the races of man; but there remains 
one important agency, namely Sexual Selection, which appears to 
have acted powerfully on man, as on many other animals. I do 
not intend to assert that sexual selection will account for all the 
differences between the races. An unexplained residuum is left, 
about which we can only say, in our ignorance, that as individu- 
als are continually born with, for instance, heads a little rounder 
or narrower, and with noses a little longer or shorter, such slight 
differences might become fixed and uniform, if the unknown 
agencies which induced them were to act in a more constant 
manner, aided by long-continued intercrossing. Such variations 
come under the provisional class, alluded to in our second chap- 
hair, which is hereditary. Now this hair is as coarse and harsh as 
that of a horse's mane, whilst the hair of other colors is fine and soft. 
^» On the odor of the skin, Godron, 'Sur I'Espece,' torn. ii. p. 217. 
On the pores in the skin, Dr. Wilckens, 'Die Aufgaben der Land- 
wirth. Zootechnik,' 1869, s. 1. 
14 



194 THE DESCENT OF MAN. 

ter, which for the want of a better term are often called spon- 
taneous. Nor do I pretend that the efCects of sexual selection can 
be indicated with scientific precision; but it can be shown that 
it would be an inexplicable fact if man had not been modified by 
this agency, which appears to have acted powerfully on innumer- 
able animals. It can further be shown that the differences be- 
tween the races of man, as in color, hairiness, form of features, 
&c., are of a kind which might have been expected to come under 
the influence of sexual selection. But in order to treat this sub- 
ject properly, I have found it necessary to pass the whole animal 
kingdom in review. I have therefore devoted to it the Second 
Part of this work. At the close I shall return to man, and, after 
attempting to show how far he has been modified through sexual 
selection, will give a brief summary of the chapters in this First 
Part. 



Note on the Resemblances and Diffeeences in the Structuee 
AND THE Development of the Beain in Man and Apes. 
By Professoe Huxley, F.E.S. 

The controversy respecting the nature and the extent of the 
differences in the structure of the brain in man and the apes, 
which arose some fifteen years ago, has not yet come to an end, 
though the subject matter of the dispute is, at present, totallj'- 
different from what it was formerly. It was originally asserted 
and re-asserted, with singular pertinacity, that the brain of all 
apes, even the highest, differs from that of man, in the absence of 
such conspicuous structures as the posterior lobes of the cerebral 
hemispheres, with the posterior cornu of the lateral ventricle and 
the hippocampus minor, contained in those lobes, which are so 
obvious in man. 

But the truth that the three structures in question are as well 
developed in apes' as in human brains, or even better; and that 
it is characteristic of all the Primates (if we exclude the Lemurs) 
to have these parts well developed, stands at present on as secure 
a basis as any proposition in comparative anatomy. Moreover, it 
is admitted by every one of the long series of anatomists who, of 
late years, have paid special attention to the arrangement of the 
complicated sulci and gyri which appear upon the surface of the 
cerebral hemispheres in man and the higher apes, that they are 
disposed after the very same pattern in him, as in them. Every 
principal gyrus and sulcus of a chimpanzee's brain is clearly rep- 
resented in that of a man, so that the terminology which applies 
to the one answers for the other. On this point there is no dif- 
ference of opinion. Some years since. Professor Bischoff pub- 



STRUCTURE OF THE BRAIN. 195 

lished a memoir™ on the cerebral convolutions of man and apes; 
and as the purpose of my learned colleague was certainly not to 
diminish the value of the differences between apes and men 
in this respect, I am g'lad to make a citation from him. 

"That the apes, and especially the orang, chimpanzee and gorilla, 
"come very close to man in their organization, much nearer than 
"to any other animal, is a well-known fact, disputed by nobody. 
"Looking at the matter from the point of view of organization 
"alone, no one probably would ever have disputed the view of 
"Linnaeus, that man should be placed, merely as a peculiar species, 
"at the head of the mammalia and of those apes. Both show. In 
"all their organs, so close an affinity, that the most exact anatomi- 
"cal investigation is needed in order to demonstrate those dif- 
"ferences which really exist. So it is with the brains. The brains 
"of man, the orang, the chimpanzee, the gorilla, in spite of all the 
"important differences which they present, come very close to one 
"another" (1. c. p. 101). 

There remains, then, no dispute as to the resemblance in funda- 
mental characters, between the ape's brain and man's; nor any 
as to the wonderfully close similarity between the chimpanzee, 
orang and man, in even the details of the arrangement of the 
gyri and sulci of the cerebral hemispheres. Nor, turning to the 
differences between the brains of the highest apes and that of man, 
is there any serious question as to the nature and extent of these 
differences. It is admitted that the man's cerebral hemispheres 
are absolutely and relatively larger than those of the orang and 
chimpanzee; that his frontal lobes are less excavated by the up- 
ward protrusion of the roof of the orbils; that his gyri and sulci 
are, as a rule, less symmetrically disposed, and present a greater 
number of secondary plications. And it is admitted that, as a rule, 
in man, the temporo-occipital or "external perpendicular" fissure, 
which is usually so strongly marked a feature of the ape's brain 
is but faintly marked. But it is also clear, that none of these dif- 
ferences constitutes a sharp demarcation between the man's and 
the ape's brain. In respect to the external perpendicular fissure 
of Gratiolet, in the human brain, for instance. Professor Turner 
remarks :^^ 

"In some brains it appears simply as an indentation of the mar- 
"gin of the hemispheres, but, in others, it extends for some distance 
"more or less transversely outwards. I saw it in the right hemis- 
"phere of a female brain pass more than two inches outwards; 
"and in another specimen, also the right hemisphere, it proceeded 

70 'Die Grosshirn-Windungen des Menschen;' 'Abhandlung-en der K. 
Bayerischen Akademie,' Bd. x., 1868. 

■^ 'Convolutions of the Human Cerebrum Topographically Consid- 
ered,' 1866, j^ 12. 



XS6 THE DESCENT OP MAN. 

"for four-tenths of an inch outwards, and then extended down- 
awards, as far as the loAver margin of the outer surface of the 
"hemisphere. The im.perfect definition of this fissure in the ma- 
"jority of human brains, as compared with its remarkable distinct- 
"ness in the brain of most Quadrumana, is owing to the presence 
"in the former, of certain superficial, well marked, secondary con- 
evolutions which bridge it over and connect the parietal with the 
"occipital lobe. The closer the first of these bridging gyri lies to 
"the longitudinal fissure, the shorter is the external parieto-occip- 
"ital fissure" (1. c. p. 12). 

The obliteration of the external perpendicular fissure of Grat- 
iolet, therefore, is not a constant character of the human brain. 
On the other hand, its full development is not a constant character 
of the higher ape's brain. For, in the chimpanzee, the more or 
less extensive obliteration of the external perpendicular sulcus by 
"bridging convolutions," on one side or the other, has been noted 
over and over again by Prof. Rolleston, Mr. Marshall, M. Broca 
and Professor Turner. At the conclusion of a special paper on 
this subject the latter writes :'^^ 

"The three specimens of the brain of a chimpanzee just de- 
"scribed, prove, that the generalization which Gratiolet has at- 
"tempted to draw of the complete absence of the first connecting 
"convolution and the concealment of the second, as essentially 
"characteristic features in the brain of this animal, is by no means 
"universally applicable. In only one specimen did the brain, in 
"these particulars, follow the law which Gratiolet has expressed. 
"As regards the presence of the superior bridging-convolution, I 
"am inclined to think that it has existed in one hemisphere, at 
"least, in a majority 6t the brains of this animal which have, up 
"to this time, been figured or described. The superficial position 
"of the second bridging convolution is evidently less frequent, and 
"has as yet, I believe, only been seen in the brain (A) recorded in 
"this communication. The asymmetrical arrangement in the con- 
"volutions of the two hemispheres, v^^^hich previous observers have 
"referred to in their descriptions is also well illustrated in these 
"specimens" (pp. 8, 9). 

Even were the presence of the temporo-occipital, or external per- 
pendicular, sulcus a mark of distinction between the higher apes 
and man, the value of such a distinctive character would be ren- 
dered very doubtful by the structure of the brain in the Platy- 
rhine apes. In fact while the temporo-occipital is one of the most 
constant of sulci in the Catarhine, or Old World, apes, it is never 
very strongly developed in the New World apes; it is absent in 

"^^ Notes more especially on the bridging- convolutions in the Brain 
of the Chimpanzee, 'Proceedings of the Royal Society of Edinburgh,' 
1865-6. 



STRUCTURE OF THE BRAIN. 197 

the smaller Platyrhini; rudimentary in Pithecia;"^ and more or 
less obliterated by bridging convolutions in Ateles. 

A cliaracter which is thus variable within the limits of a single 
group can have no great taxonomic value. 

It is further established, that the degree of asymmetry of the 
convolution of the two sides in the human brain is subject to 
much individual variation; and that, in those individuals of the 
Bushman race who have been examined, the gyri and sulci of the 
two hemispheres are considerably less complicated and more sym- 
metrical than in the European brain, while, in some individuals 
of the chimpanzee, their complexity and asymmetry become no- 
table. This is particularly the case in the brain of a young male 
chimpanzee figured by M. Broca. ('L'ordre des Primates,' p. 165, 
fig. 11.) 

Again, as respects the question of absolute size, it is. estab- 
lished that the difference between the largest and the smallest 
healthy human brain is greater than the difference between the 
smallest healthy human brain and the largest chimpanzee's or 
' orang's brain. 

Moreover, there is one circumstance in which the orang's and 
chimpanzee's brains resemble man's but in which they differ from 
the lower apes, and that is the presence of two corpora candicantia 
— the Cynomorpha having but one. 

In view of these facts I do not hesitate in this year 1874, to re- 
peat and insist upon the proposition which I enunciated in 186.S.'* 

"So far as cerebral structure goes, therefore, it is clear that man 
"differs less from the chimpanzee or the orang, than these do even 
"from the monkeys, and that the difference between the brain of 
"the chimpanzee and of man is almost insignificant, when ccm- 
"pared with that between the chimpanzee brain and that of a Le- 
*'mur." 

In the paper to which I have referred. Professor Bischoff does 
not deny the second part of this statement, but he first makes the 
irrelevant remark that it is not wonderful if the brains of an orang 
and a l^emur are very different; and secondly, goes on to assert 
that, "if we successively compare the brain of a man with that of 
"an orang; the brain of this with that of a chimpanzee; of this 
"with that of a gorilla, and so on of a Hylobates, Semnopithecus, 
•'Cynocephalus, Cercopithecus, Macacus, Cebus, Callithrix, Lemur, 
"Stenops, Hapale, we shall not meet with a greater or even as 
"great a break in the degree of development of the convolutions, 
"as we find between the brain of a man and that of an orang or 
"chimpanzee." 



^3 Flower 'On the Anatomy of Pithecia Monachus,' 'Proceedings of 
the Zoological Society,' 1862. 
■^^ 'Man's Place in Nature,' p. 102. 
14 



198 THE DESCENT OF MAN. 

To wliich I reply, firstly, that whether this assertion be true o* 
false, it has nothing whatever to do with the proposition enun- 
ciated in 'Man's Place in Nature,' which refers not to the develop- 
ment of the convolutions alone, but to the structure of the whole 
brain. If Professor Bischoff had taken the trouble to refer to p. 
96 of the work he criticizes, in fact, he would have found the fol- 
lowing passage: "And it is a remarkable circumstance that 
"though, so far as our present knowledge extends, there is one 
"true structural break in the series of forms of Simian brains, 
"this hiatus does not lie between man and the manlike apes, but 
"between the lower and the lowest Simians, or in other words, 
"between the Old and New World apes and monkeys and the Le- 
"murs. Every Lemur which has yet been examined, in fact, has 
''its cerebellum partially visible from above; and its posterior lobe, 
"with the contained posterior cornu and hippocampus minor, more 
"or less rudimentary. Every marmoset, American monkey. Old 
"World monkey, baboon, or manlike ape, on the contrary, has its 
"cerebellum entirely hidden, posteriorly, by the cerebral lobes, and 
"possesses a large posterior cornu with a well-developed hippo- 
"campus minor." 

This statement was a strictly accurate account of what was 
known when it was made; and it does not appear to me to be more 
than apparently weakened by the subsequent discovery of the 
relatively small development of the posterior lobes in the Siamang 
and in the Howling monkey. Notwithstanding the exceptional 
brevity of the posterior lobes in these two species, no one will 
pretend that their brains, in the slightest degree, approach those 
of the Lemurs. And if, instead of putting Hapale out of its nat- 
ural place, as Professor BischofE most unaccountably does, we 
write the series of animals he has chosen to mention as follows: 
Homo, Pithecus, Troglodytes, Hylobates, Semnopithecus, Cynoce- 
phalus, Cercopithecus, Macacus, Cebus, Callithrix, Hapale, Lemur, 
Stenops, I venture to reaffirm that the great break in this series 
lies between Hapale and Lemur, and that this break is consid- 
erably greater than that between any other two terms of that 
series. Professor Bischoff ignores the fact that long before he 
wrote, Gratiolet had suggested the separation of the Lemurs from 
the other Primates on the very ground of the difference in their 
cerebral characters; and that Professor Flower had made the fol- 
lowing obervations in the course of his description of the brain of 
the Javan Loris.^^ 

"And it is especially remarkable that, in the development of the 
"posterior lobes, there is no approximation to the Lemurine, short 
"hemisphered, brain, in those monkeys which are commonly sup- 



's 'Transactions of the Zoological Society,' vol. v. 1862. 



STRUCTURE OF THE BRAIN. 199 

"posed to approach this family in other respects, viz., the lower 
"members of the Platyrhine group." 

So far as the structure of the adult brain is concerned, then, the 
very considerable additions to our knowledge, which have been 
made by the researches of so many investigators, during the past 
ten years, fully justify the statement which I made in 1863. But 
it has been said that, admitting the similarity between the adult 
brains of man and apes, they are nevertheless, in reality, widely 
different, because they exhibit fundamental differences in the 
mode of their development. No one would be more ready than 
I to admit the force of this argument, if such fundamental dif- 
ferences of development really exist. But I deny that they do 
exist. On the contrary, there is a fundamental agreement in the 
development of the brain in men and apes. 

Gratiolet originated the statement that there is a fundamental 
difference in the development of the brains of apes and that of 
man — consisting of this; that, in the apes, the sulci which first 
make their appearance are situated on the posterior region of the 
cerebral hemispheres, while, in the human foetus, the sulci first be- 
come visible on the frontal lobes.'® 

This general statement is based upon two observations, the one 
of a Gibbon almost ready to be born, in which the posterior gyri 
were "well developed," while those of the frontal lobes were 
"hardly indicated""^ (1. c. p. 39), and the other of a human foetus 
at the 22nd or 23rd week of uterogestation, in which Gratiolet notes 
that the insula was uncovered, but that nevertheless "des incis- 
es "Chez tous les singes, les plis posterieurs se developpent les pre- 
"miers; les plis anterieurs se developpent plus tard, aussi la vertebre 
"occipitale et la parietale sont-elles relativement tresgrandes chez le 
"foetus L'Homme presente une exception remarquable quant a 
"I'epoque de I'apparition des plis frontaux, qui sont les premiers in- 
"diques; mais le developpement general du lobe frontal, envisage 
"seulement par rapport a son volume, suit les memes lois que dans 
"les singes:" Gratiolet, 'Memoire sur les plis cerebraux de THomme 
et des Primates,' p. 39, tab. iv. fig. 3. 

" Gratiolet's words are (1. c. p. 39): "Dans le foetus dont il s'agit 
"les plis cerebraux posterieurs sont bien developpes, tandis que les 
"plis du lobe frontal sont a peine indiques." The figure, however 
(PI. iv. fig. 3), shows the fissure of Rolando, and one of the frontal 
sulci, plainly enough. Nevertheless, M. Alix, in his 'Notice sur les 
travaux anthropologiques de Gratiolet' (Mem. de la Societe d'Anthro- 
pologie de Paris, 1868, p. 32), writes thus: "Gratiolet a eu entre les 
"mains le cerveau d'un foetus de Gibbon, singe eminemment supe- 
"rieur, et tellement rapproche de I'orang, que des naturalistes tres- 
"competents I'ont range parmi les anthropoides. M. Huxley, par ex- 
"emple, n'hesite pas sur ce point. Eh bien, c'est sur le cerveau d'un 
"foetus de Gibbon que Gratiolet a vu les circonvolutions du lobe tem- 
"poro-sphenoidal deja developpees lorsqu'il n'existent pas encore de 



200 THE DESCENT OF MAN. 

"ures sement le lobe antGrieur, une scissure peu profonde indique 
"la separation dii lobe occipital, tres-reduit d'ailleurs des cette 
"epoque. Le reste de la surface cerebrale est encore absolument 
"lisse." 

Three views of the brain are given in Plate II. figs. 1, 2, 3, of 
the work cited, showing the upper, lateral and inferior views of 
the hemispheres, but not the inner view. It is worthy of note 
that the figure by no means bears out Gratiolet's description, inas- 
much as the fissure (anterotemporai) on the posterior half of the 
face of the hemisphere is more marked than any of those vaguely 
indicated in the anterior half. If the figure is correct it in no way 
justifies Gratiolet's conclusion: "II y a done entre ces cerveaux 
"[those of a Callithrix and of a Gibbon] et celui du foetus humain 
"une difference fondamental. Chez celui-ci, longtemps avant que 
"les plis temporaux apparaissent, les plis frontaux essayent d'ex- 
"ister." 

Since Gratiolet's time, however, the development of the gyri and 
sulci of the brain has been made the subject of renewed investiga- 
tion by Schmidt, Bischoff, Pansch,^^ and more particularly by 
Ecker,'^^ whose work is not only the latest, but by far the most 
complete, memoir on the subject. 

The final results of their inquiries may be summed up as fol- 
lows: — 

1. In the human foetus, the sylvian fissure is formed in the 
course of the third month of uterogestation. In this, and in the 
fourth mouth, the cerebral hemispheres are smooth and rounded 
(with the exception of the sylvian depression), and they project 
backwards far beyond the cerebellum. 

2. The sulci, properly so called, begin to appear in the interval 
between the end of the fourth and the beginning of the sixth 
month of foetal life, but Ecker is careful to point out that, not 
only the time, but the order, of their appearance is subject to con- 
siderable individual variation. In no case, however, are either 
the frontal or the temporal sulci the earliest. 

The first which appears, in fact, lies on the inner face of the 
hemisphere (whence doubtless Gratiolet, who does not seem to 
have examined that face in his foetus, overlooked it), and is either 

"plis sur le lobe frontal. II etait done bien autorise a dire que, chez 
"I'honime les circonvolutions apparaissent d'CL en oo, tandis que chez 
"les singes elles se developpent d'cj en a." 

''^ 'Ueber die typische Anordnung der Furchen und Windung-en auf 
den Grosshirn-Hemispharen des Menschen und der Affen.' 'Archiv 
fur Anthropolog'ie,' iii., 1868. 

■^8 'Zur Entwickelungs Geschichte der Furchen und Windungen der 
Grosshirn-Hemispharen im Foetus des Menschen.' 'Archiv fur An- 
thropologie,' iii., 1868. 



STRUCTURE OF THE BRAIN. 201 

the internal perpendicular (occipito-parietal), or the calcarine sul- 
cus, these two being close together and eventually running into 
one another. As a rule the occipito-parietal is the earlier of the 
two. 

3. At the latter part of this period, another sulcus, the "posterio, 
parietal," or "Fissure of Rolando" is developed, and it is followed, 
in the course of the sixth month, by the other principal sulci of the 
frontal, parietal, temporal and occipital lobes. There is, how- 
ever, no clear evidence that one of these constantly appears be- 
fore the other; and it is remarkable that, in the brain at the 
period described and figured by Ecker (1. c. p. 212-13, Taf. II. figs, 1, 
2, 3, 4), the antero-temporal sulcus (scissure parallele) so charac- 
teristic of the ape's brain, is as well, if not better developed than 
the fissure of Rolando, and is much more marked than the proper 
frontal sulci. 

Taking the facts as they now stand, it appears to me that the 
order of the appearance of the sulci and gyri in the fcetal human 
brain is in perfect harmony with the general doctrine of evolu- 
tion, and with the view that man has been evolved from some 
ape-like form; though there can be no doubt that that form was, 
in many respects, different from any member of the Primates now 
living. 

Von Baer taught us, half a century ago, that, in the course of 
their development, allied animals put on, at first, the characters of 
the greater groups to which they belong, and, by degrees, assume 
those which restrict them within the limits of their family, genus, 
and species; and he proved, at the same time, that no develop- 
mental stage of a higher animal is precisely similar to the adult 
condition of any lower animal. It is quite correct to say that a 
frog passes through the condition of a fish, inasmuch as at one 
period of its life the tadpole has all the characters of a fish, and, 
if it went no further, would have to be grouped among fishes. 
But it is equally true that a tadpole is very different from any 
known fish. 

In like manner, the brain of a human foetus, at the fifth month, 
may correctly be said to be, not only the brain of an ape, but that 
of an Arctopithecine or marmoset-like ape; for its hemispheres, 
with their great posterior lobster, and with no sulci but the syl- 
vian and the calcarine, present the characteristics found only in 
the group of the Arctopithecine Primates, But it is equally true, 
as Gratiolet remarks, that, in its widely open sylvian fissure, it 
differs from the brain of any actual marmoset. No doubt it would 
be much more similar to the brain of an advanced foetus of a 
marmoset. But we know nothing whatever of the development of 
the brain in the marmosets. In the Platyrhini proper, the only 
observation with which I am acquainted is due to Pansch, who 
found in the brain of a foetal Cebus Apella, in addition to the 



202 THE DESCENT OF MAN. 

sylvian fissure and the deep calcarine fissure, only a very shallow 
anterotemporal fissure (scissure parallele of Gratiolet). 

Now this fact, taken together with the circumstance that the 
anterotemporal sulcus is present in such Platyrhini as the Sai- 
miri, which present mere traces of sulci on the anterior half of 
the exterior of the cerebral hemispheres, or none at all, undoubt- 
edly, so far as it goes, affords fair evidence in favor of Gratiolet's 
hypothesis, that the posterior sulci appear before the anterior, in 
the brains of the Platyrhini. But, it by no means follows, that 
the rule which may hold good for the Platyrhini extends to the 
Catarhini. We have no information whatever respecting the de- 
velopment of the brain in the Cynomorpha; and, as regards the 
Anthropomorpha, nothing but the account of the brain of the 
Gibbon, near birth, already referred to. At the present moment, 
there is not a shadow of evidence to show that the sulci of a chim- 
panzee's, or orang's, brain do not appear in the same order as a 
man's. 

Gratiolet opens his preface with the aphorism, "II est dangereux 
"dans les sciences de conclure trop vite." I fear he must have for- 
gotten this sound maxim by the time he had reached the discus- 
sion of the differences between men and apes, in the body of his 
work. No doubt, the excellent author of one of the most re- 
markable contributions to the just understanding of the mammal- 
ian brain which has ever been made, would have been the first 
to admit the insufiiciency of his data had he lived to profit by the 
advance of inquiry. The misfortune is that his conclusions have 
been employed by persons incompetent to appreciate their foun- 
dation, as arguments in favor of obscurantism.^" 

But it is important to remark that, whether Gratiolet was right 
or wrong in his hypothesis respecting the relative order of appear- 
ance of the temporal and frontal sulci, the fact remains; that, be- 
fore either temporal or frontal sulci, appear, the foetal brain of 
man presents characters which are found only in the lowest group 
of the Primates (leaving out the Lemurs) ; and that this is ex- 
actly what we should expect to be the case, if man has resulted 
from the gradual modification of the same form as that from 
which the other Primates have sprung. 

^'^ For example, M. I'Abbe Lecomte in his terrible pamphlet 'Le Dar- 
winisme et I'origine de I'Homme,' 1873. 



SEXUAL SELECTION. 203 



PART IL 

SEXUAL SELECTION. 



CHAPTER VIII. 
PRINCIPLES OF SEXUAL SELECTION. 

Secondary sexual characters— Sexual selection — Manner of action- 
Excess of males— Polygamy— The male alone generally modified 
through sexual selection— Eagerness of the male — Variability of 
the male — Choice exerted by the female — Sexual compared with 
natural selection — Inheritance, at corresponding periods of life, 
at corresponding seasons of the year, and as limited by sex — Re- 
lations between the several forms of inheritance — Causes why one 
sex and the young are not modified through sexual selection— Sup- 
plement on the proportional numbers of the two sexes throughout 
the animal kingdom — The proportion of the sexes in relation to 
natural selection. 

With animals which have their sexes separated, the males 
necessarily differ from the females in their organs of reproduc- 
tion; and these are the primary sexual characters. But the 
sexes often differ in what Hunter has called secondary sexual 
characters, which are not directly connected with the act of re- 
production; for instance, the male possesses certain organs of 
sense or locomotion, of which the female is quite destitute, or has 
them more highly-developed, in order that he may readily find or 
reach her; or again the male has special organs of prehension 
for holding her securely. These latter organs, of infinitely di- 
versified kinds, graduate into those which are commonly ranked 
as primary, and in some cases can hardly be distinguished from 
them; we see instances of this in the complex appendages at the 
apex of the abdomen in male insects. Unless indeed we confine 
the term "primary" to the reproductive glands, it is scarcely 
possible to decide v/hich ought to be called primary and which 
secondary. 

The female often differs from the male in having organs for 



204 THE DESCENT OF MAN. 

the nourishment or protection of her young, such as the mam- 
mary glands of mammals, and the abdominal sacks of the marsu- 
pials. In some few cases also the male possesses similar organs, 
which are wanting in the female, such as the receptacles for the 
ova in certain male fishes, and those temporarily developed in 
certain male frogs. The females of most bees are provided with 
a special apparatus for collecting and carrying pollen, and their 
ovipositor is modified into a sting for the defense of the larva3 and 
the community. Many similar cases could be given, but they do 
not here concern us. There are, however, other sexual differ- 
ences quite unconnected with the primary reproductive organs, 
and it is with these that we are more especially concerned — such 
as the greater size, strength, and pugnacity of the male, his 
weapons of offense or means of defense against rivals, his gaudy 
coloring and various ornaments, his power of song, and other 
such characters. 

Besides the primary and secondary sexual differences, such as 
the foregoing, the males and females of some animals differ in 
structures related to different habits of life, and not at all, or 
only indirectly, to the reproductive functions. Thus the females 
of certain flies (Culicidse and Tabanidse) are blood-suckers, 
whilst the males, living on flowers, have mouths destitute of 
mandibles.^ The males of certain moths and of some crustaceans 
(e. g. Tanais) have imperfect, closed mouths, and cannot feed. 
The complemental males of certain Cirripedes live like epiphytic 
plants either on the female or the hermaphrodite form, and are 
destitute of a mouth and of prehensile limbs. In these cases it is 
the male which has been modified, and has lost certain important 
organs, which the females possess. In other cases it is the fe- 
male which has lost such parts; for instance, the female glow- 
worm is destitute of wings, as also are many female moths, some 
of which never leave their cocoons. Many female parasitic crus- 
taceans have lost their natatory legs. In some weevil-beetles 
(Curculionidae) there is a great difference betv\/^een the male and 
female in the length of the rostrum or snout;- but the meaning 
of this and of many analogous differences, is not at all under- 
stood. Differences of structure between the two sexes in relation 
to different habits of life are generally confined to the lower ani- 
mals; but with some few birds the beak of the male differs from 
that of the female. In the Huia of New Zealand the difference is 
wonderfully great, and we hear from Dr. Buller^ that the male 
uses his strong beak in chiselling the larvae of insects out of de- 

1 Westwood, 'Modern Class, of Insects,' vol. ii. 1840, p. 541. For the 
statement about Tanais, mentioned below, I am indebted to Fritz 
Muller. 

2 Kirby and Spence, 'Introduction to Entomology,' vol. iii. 1826, p. 309. 

3 'Birds of New Zealand,' 1872, p. 66. 



SEXUAL SELECTION. 205 

cayed wood, whilst the female probes the softer parts with her 
far longer, much curved and pliant beak: and thus they mu- 
tually aid ea^h other. In most cases, differences of structure 
between the sexes are more or less directly connected with the 
propagation of the species: thus a female, which has to nourish 
a multitude of ova, requires more food than the male, and con- 
sequently requires special means for procuring it. A male ani- 
mal, which lives for a very short time, might lose its organs for 
procuring food through disuse, without detriment; but he would 
retain his locomotive organs in a perfect state, so that he might 
reach the female. The female, on the other hand, might safely 
lose her organs for flying, swimming, or walking, if she gradu- 
ally acquired habits which rendered such powers useless. 

We are, however, here concerned only with sexual selection. 
This depends on the advantage which certain individuals have 
over others of the same sex and species solely in respect of repro- 
duction. When, as in the cases above mentioned, the two sexes 
differ in structure in relation to different habits of life, they have 
no doubt been modified through natural selection, and by in- 
heritance limited to one and the same sex. So again the primary 
sexual organs, and those for nourishing or protecting the young, 
come under the same influence; for those individuals which gen- 
erated or nourished their offspring best, would leave, casteris 
paribus, the greatest number to inherit their superiority; whilst 
those which generated or nourished their offspring badly, would 
leave but few to inherit their weaker powers. As the male has 
to flnd the female, he requires organs of sense and locomotion, 
but if these organs are necessary for the other purposes of life, 
as is generally the case, they will have been developed through 
natural selection. When the male has found the female, he 
sometimes absolutely requires prehensile organs to hold her; 
thus Dr. Wallace informs me that the males of certain moths 
cannot unite with the females if their tarsi or feet are broken. 
The males of many oceanic crustaceans, when adult, have their 
legs and antennas modified in an extraordinary manner for the 
prehension of the female; hence we may suspect that it is be- 
cause these animals are washed about by the waves of the open 
sea, that they require these organs in order to propagate their 
kind, and if so, their development has been the result of ordinary 
or natural selection. Some animals extremely low in the scale 
have been modified for this same purpose; thus the males of 
certain parasitic worms, when fully grown, have the lower sur- 
face of the terminal parts of their bodies roughened like a rasp, 
and with this they coil round and permanently hold the females.* 

* M. Perrier advances this case ('Revue Scientiflque/ Feb. 1, 1873, 
p. 865) as one fatal to the belief in sexual selection, inasmuch as he 
supposes that I attribute all the differences between the sexes to 



2561 THE DESCENT OF MAN. 

When the two sexes follow exactly the same habits of life, and 
the male has the sensory or locomotive organs more highly de- 
veloped than those of the female, it may be that the perfection of 
these is indispensable to the male for finding the female; but in 
the vast majority of cases, they serve only to give one male an 
advantage over another, for with sufficient time, the less well- 
endowed males would succeed in pairing with the females; and 
judging from the structure of the female, they would be in all 
other respects equally well adapted for their ordinary habits of 
life. Since in such cases the males have acquired their present 
structure, not from being better fitted to survive in the struggle 
for existence, but from having gained an advantage over other 
males, and from having transmitted this advantage to their male 
offspring alone, sexual selection must here have come into action. 
It was the importance of this distinction which led me to desig- 
nate this form of selection as Sexual Selection. So again, if the 
chief service rendered to the male by his prehensile organs is to 
prevent the escape of the female before the arrival of other 
males, or when assaulted by them, these organs will have been 
perfected through sexual selection, that is by the advantage ac- 
quired by certain individuals over their rivals. But in most cases 
of this kind it is impossible to distinguish between the effects of 
natural and sexual selection. Whole chapters could be filled 
with details on the differences between the sexes in their sensory, 
locomotive, and prehensile organs. As, however, these struc- 
tures are not more interesting than others adapted for the or- 
dinary purposes of life I shall pass them over almost entirely, 
giving only a few instances under each class. 

There are many other structures and instincts which must have 
been developed through sexual selection — such as the weapons 
of offense and the means of defense of the males for fighting 
with and driving away their rivals — their courage and pugnacity 
— their various ornaments — their contrivances for producing vo- 
cal or instrumental music — and their glands for emitting odors, 
most of these latter structures serving only to allure or excite 
the female. It is clear that these characters are the result of 
sexual and not of ordinary selection, since unarmed, unorna- 
mented, or unattractive males would succeed equally well in the 

sexual selection. This disting-uished naturalist, therefore, like so 
many other Frenchmen, has not taken the trouble to understand even 
the first principles of sexual selection. An English naturalist insists 
that the claspers of certain male animals could not have been de- 
veloped throug-h the choice of tlie female! Had I not met with this 
remark, I should not have thought it possible for any one to have 
read this chapter and to have imagined that I maintain that the 
choice of the female had anything to do with the development of the 
prehensile organs in the male. 



SEXUAL SELECTION. 207 

battle for life and in leaving a numerous progeny, but for the 
presence of better endowed males. We may infer that this 
would be the case, because the females, which are unarmed and 
unornamented, are able to survive and procreate their kind. 
Secondary sexual characters of the kind just referred to, will be 
fully discussed in the following chapters, as being in many re- 
spects interesting, but especially as depending on the will, choice, 
and rivalry of the individuals of either sex. When we behold 
two males fighting for the possession of the female, or several 
male birds displaying their gorgeous plumage, and performing 
strange antics before an assembled body of females, we cannot 
doubt that, though led by instinct, they know what they are 
about, and consciously exert their mental and bodily powers. 

Just as man can improve the breed of his game-cocks by the 
selection of those birds which are victorious in the cockpit, so it 
appears that the strongest and most vigorous males, or those pro- 
vided with the best weapons, have prevailed under nature, and 
have led to the improvement of the natural breed or species. A 
slight degree of variability leading to some advantage, however 
slight, in reiterated deadly contests would suflBce for the work of 
sexual selection; and it is certain that secondary sexual charac- 
ters are eminently variable. Just as man can give beauty, ac- 
cording to his standard of taste, to his male poultry, or more 
strictly can modify the beauty originally acquired by the parent 
species, can give to the Sebright bantam a new and elegant 
plumage, an erect and peculiar carriage — so it appears that fe- 
male birds in a state of nature, have by a long selection of the 
more attractive males, added to their beauty or other attractive 
qualities. No doubt this implies powers of discrimination and 
taste on the part of the female which will at first appear ex- 
tremely improbable; but by the facts to be adduced hereafter, I 
hope to be able to show that the females actually have these 
powers. T^Hien, however, it is said that the lower animals have 
a sense of beauty, it must not be supposed that such sense is 
comparable with that of a cultivated man, with his multiform 
and complex associated ideas. A more just comparison would 
be between the taste for the beautiful in animals, and that in the 
lowest savages, who admire and deck themselves with any bril- 
liant, glittering, or curious object. 

From our ignorance on several points, the precise manner in 
which sexual selection acts is somewhat uncertain. Neverthe- 
less if those naturalists who already believe in the mutability of 
species, will read the following chapters, they will, I think, agree 
with me, that sexual selection has played an important part in 
the history of the organic world. It is certain that amongst al- 
most all animals there is a struggle between the males for the 
possession of the female. This fact is so notorious that it would 



208 THE DESCENT OF MAN. 

be superfluous to give instances. Hence the females have the 
opportunity of selecting one out of several males, on the suppo- 
sition that their mental capacity suffices for the exertion of a 
choice. In many cases special circumstances tend to make the 
struggle between the males particularly severe. Thus the males 
of our migratory birds generally arrive at their places of breed- 
ing before the females, so that many males are ready to contend 
for each female. I am informed by Mr. Jenner Weir, that the 
bird-catchers assert that this is invariably the case with the 
nightingale and blackcap, and with respect to the latter he can 
himself confirm the statement. 

Mr. Swaysland of Brighton has been in the habit, during the 
last forty years, of catching our migratory birds on their first 
arrival, and he has never known the females of any species to 
arrive before their males. During one spring he shot thirty-nine 
males of Ray's wagtail (Budytes Raii) before he saw a single fe- 
male. Mr. Gould has ascertained by the dissection of those 
snipes which arrive the first in this country, that the males come 
before the females. And the like holds good with most of the 
migratory birds of the United States.^ The majority of the male 
salmon in our rivers, on coming up from the sea, are ready to 
breed before the females. So it appears to be with frogs and 
toads. Throughout the great class of insects the males almost 
always are the first to emerge from the pupal state, so that they 
generally abound for a time before any females can be seen.® 
The cause of this difference between the males and females in 
their periods of arrival and maturity is sufficiently obvious. 
Those males which annually first migrated into any country, or 
which in the spring were first ready to breed, or were the most 
eager, would leave the largest number of offspring; and these 
would tend to inherit similar instincts and constitutions. It 
must be borne in mind that it would have been impossible to 
change very materially the time of sexual maturity in the fe- 
males, without at the same time interfering with the period of 
the production of the young — a period which must be determined 
by the seasons of the year. On the whole there can be no doubt 
that with almost all animals, in which the sexes are separate, 
there is a constantly recurrent struggle between the males for the 
possession of the females. 

B J, A. Allen, on the 'Mammals and Winter Birds of Florida,' Bull. 
Comp. Zoology, Harvard College, p. 268. 

« Even with those plants in which the sexes are separate, the male 
flowers are generally mature before the female. As first shown by 
C. K. Sprengel, many hermaphrodite plants are dichogamous; that 
is, their male and female organs are not ready at the same time, so 
that they cannot be self-fertilized. Now in such flowers, the pol- 
len is in general matured before the stigma, though there are excep- 
tional cases in which the female organs are beforehand. 



Sexual selection. 209 

Our difficulty in regard to sexual selection lies in understand- 
ing how it is that the males which conquer other males, or those 
which prove the most attractive to the females, leave a greater 
number of offspring to inherit their superiority than their beaten 
and less attractive rivals. Unless this result does follovf, the 
characters which give to certain males an advantage over others, 
could not be perfected and augmented through sexual selection. 
When the sexes exist in exactly equal numbers, the worst-en- 
dowed males will (except v/here polygamy prevails), ultimately 
find females, and leave as many offspring, as well fitted for their 
general habits of life, as the best-endowed males. From various 
facts and considerations, I formerly inferred that with most ani- 
mals, in which secondary sexual characters are well developed, 
the males considerably exceeded the females in number; but this 
is not by any means always true. If the males were to the fe- 
males as two to one, or as three to two, or even in a somewhat 
lower ratio, the whole affair would be simple; for the better- 
armed or more attractive males would leave the largest number 
of offspring. But after investigating, as far as possible, the nu- 
merical proportion of the sexes, I do not believe that any great 
inequality in number commonly exists. In most cases sexua/1 
selection appears to have been effective in the following manner. 

Let us take any species, a bird for instance, and divide the fe- 
males inhabiting a district into two equal bodies, the one con- 
sisting of the more vigorous and better-nourished individuals 
and the other of the less vigorous and healthy. The former, 
there can be little doubt, would be ready to breed in the spring 
before the others; and this is the opinion of Mr. Jenner Weir, 
who has carefully attended to the habits of birds during many 
years. There can also be no doubt that the most vigorous, best- 
nourished and earliest breeders would on an average succeed in 
rearing the largest number of fine offspring.'' The males, as we 
have seen, are generally ready to breed before the females; the 
strongest, and with some species the best armed of the males, 
drive away the weaker; and the former v/ould then unite with 
the more vigorous and better-nourished females, because they are 
the first to breed.^ Such vigorous pairs would surely rear a 

'' Here is excellent evidence on the character of the offspring from 
an experienced ornithologist. Mr. J. A. Allen, in speaking ('Mam- 
mals and Winter Birds of E. Florida,' p. 229) of the later broods, after 
the accidental destruction of the first, says, that these "are found to 
"be smaller and paler-colored than those hatched earlier in the sea- 
"son. In cases where several broods are reared each year, as a gen- 
"eral rule the birds of the earlier broods seem in all respects the 
"most perfect and vigorous." 

s Hermann Muller has come to this same conclusion with respect 
to those female bees which are the first to emerge from the pupa 
15 



210 THE DESCENT OF MAN. 

larger number of offspring than the retarded females, which 
would be compelled to unite with the conquered and less power- 
ful males, supposing the sexes to be numerically equal; and this 
is all that is wanted to add, in the course of successive genera- 
tions, to the size, strength and courage of the males, or to im- 
prove their weapons. 

But in very many cases the males which conquer their rivals, 
do not obtain possession of the females, independently of the 
choice of the latter. The courtship of animals is by no means so 
simple and short an affair as might be thought. The females are 
most excited by, or prefer pairing with, the more ornamented 
males, or those which are the best songsters, or play the best 
antics; but it is obviously probable that they would at the same 
time prefer the more vigorous and lively males, and this has in 
some cases been cpnfirmed by actual observation.^ Thus the 
more vigorous females, which are the first to breed, will have the 
choice of many males; and though they may not always select 
the strongest or best armed, they will select those which are 
vigorous and well armed, and in other respects the most at- 
tractive. Both sexes, therefore, of such early pairs would, as 
above explained, have an advantage over others in rearing off- 
spring; and this apparently has sufficed during a long course of 
generations to add not only to the strength and fighting powers 
of the males, but likewise to their various ornaments or other at- 
tractions. 

In the converse and much rarer case of the males selecting par- 
ticular females, it is plain that those which were the most vigor- 
ous and had conquered others, would have the freest choice; and 
it is almost certain that they would select vigorous as well as at- 
tractive females. Such pairs would have an advantage in rear- 
ing offspring, more especially if the male had the power to de- 
fend the female during the pairing-season as occurs with some 
of the higher animals, or aided her in providing for the young. 
The same principles would apply if each sex preferred and se- 
lected certain individuals of the opposite sex; supposing that 
they selected not only the more attractive, but likewise the more 
vigorous individuals. 

Nvcmerical Proportion of the Two Sexes. — I have remarked 
that sexual selection would be a simple affair if the males were 
considerably more numerous than the females. Hence I was led 



each year. See his remarkable essay, 'Anwendung der Darwin'schen 
Lehre auf Bienen,' 'Verh. d. V. Jahrg.' xxix. p. 45. 

» With respect to poultry, I have received information, hereafter to 
be given, to this effect. Even with birds, such as pigeons, which 
pair for life, the female, as I hear from Mr. Jenner Weir, will desert 
her mate if he is injured or grows weak. 



SEXUAL SELECTION. 211 

to investigate, as far as I could, the proportions between the two 
sexes of as many animals as possible; but the materials are 
scanty. I will here give only a brief abstract of the results, re- 
taining the details for a supplementary discussion, so as not to 
interfere with the course of my argument. Domesticated ani- 
mals alone afford the means of ascertaining the proportional 
numbers at birth; but no records have been specially kept for 
this purpose. By indirect means, however, I have collected a con- 
siderable body of statistics, from which it appears that with 
most of our domestic animals the sexes are nearly equal at birth. 
Thus 25,560 births of race-horses have been recorded during 
twenty-one years, and the male births were to the female births 
as 99.7 to 100. In greyhounds the inequality is greater than with 
any other animal, for out of 6878 births during twelve years, the 
male births were to the female as 110.1 to 100. It is, however, in 
some degree doubtful whether it is safe to infer that the propor- 
tion would be the same under natural conditions as under do- 
mestication; for slight and unknown differences in the conditions 
affect the proportion of the sexes. Thus with mankind, the male 
births in England are as 104.5, in Russia as 108.9, and with the 
Jews of Livonia as 120, to 100 female births. But I shall recur 
to this curious point of the excess of male births in the supple- 
ment to this chapter. At the Cape of Good Hope, however, male 
children of European extraction have been born during several 
years in the proportion of between 90 and 99 to 100 female chil- 
dren. 

For our present purpose we are concerned with the proportion 
of the sexes, not only at birth, but also at maturity, and this adds 
another element of doubt; for it is a well ascertained fact that 
with man the number of males dying before or during birth, and 
during the first few years of infancy, is considerably larger than 
that of females. So it almost certainly is with male lambs, and 
probably with some other animals. The males of some species 
kill one another by fighting; or they drive one another about 
until they become greatly emaciated. They must also be often 
exposed to various dangers, whilst wandering about in eager 
search for the females. In many kinds of fish the males are 
much smaller than the females, and they are believed often to be 
devoured by the latter, or by other fishes. The females of some 
birds appear to die earlier than the males; they are also liable to 
be destroyed on their nests, or whilst in charge of their young. 
With insects the female larvae are often larger than those of the 
males, and would consequently be more likely to be de- 
voured. In some cases the mature females are less active and 
less rapid in their movements than the males, and could not es- 
cape so well from danger. Hence, with animals in a state of na- 
ture, we must rely on mere estimation, in order to judge of the 



212 THE DESCENT OF MAN. 

proportions of the sexes at maturity; and tliis is but little trust- 
worthy, except when the inequality is strongly marked. Never- 
theless, as far as a judgment can be formed, we may conclude 
from the facts given in the supplement, that the males of some 
few mammals, of many birds, of some fish and insects, are con- 
siderably more numerous than the females. 

The proportion between the sexes fluctuates slightly during 
successive years: thus with race-horses, for every 110 mares born 
the stallions varied from 107.1 in one year to 92.6 in another year, 
and with greyhounds from 116.3 to 95.3. But had larger num- 
bers been tabulated throughout an area more extensive than Eng- 
land, these fluctuations would probably have disappeared; and 
such as they are, would hardly suffice to lead to effective sexual 
selection in a state of nature. Nevertheless, in the cases of 
some few wild animals, as shown in the supplement, the propor- 
tions seem to fluctuate either during different seasons or in dif- 
ferent localities in a sufficient degree to lead to such selection. 
For it should be observed that any advantage, gained during cer- 
tain years or in certain localities by those males which were able 
to conquer their rivals, or were the most attractive to the females, 
would probably be transmitted to the offspring, and would not 
subsequently be eliminated. During the succeeding seasons, 
when, from the equality of the sexes, every male was able to pro- 
cure a female, the stronger or more attractive males previously 
produced would still have at least as good a chance of leaving off- 
spring as the weaker or less attractive. 

Polygamy. — The practice of polygamy leads to the same results 
as would follow from an actual inequality in the number of the 
sexes; for if each male secures two or more females, many males 
cannot pair; and the latter assuredly will be the weaker or less 
attractive individuals. Many mammals and some few birds are 
polygamous, but with animals belonging to the lower classes I 
have found no evidence of this habit. The intellectual powers 
of such animals are, perhaps, not sufficient to lead them to collect 
and guard a harem of females. That some relation exists be- 
tween polygamy and the development of secondary sexual char- 
acters, appears nearly certain; and this supports the view that a 
numerical preponderance of males would be eminently favorable 
to the action of sexual selection. Nevertheless many animals, 
which are strictly monogamous, especially birds, display strongly- 
marked secondary sexual characters; whilst some few animals, 
which are polygamous, do not have such characters. 

We will first briefly run through the mammals, and then turn 
to birds. The gorilla seems to be polygamous, and the male dif- 
fers considerably from the female; so it is with some baboons, 
which live in herds containing twice as many adult females as 



SEXUAL SELECTION. 213 

males. In South America tlie Mycetes caraya presents well- 
marked sexual differences, in color, beard, and vocal organs; and 
the male generally lives with two or three wives: the male of the 
Cebus capucinus differs somewhat from the female, and appears 
to he polygamous.^" Little is known on this head with respect 
to most other monkeys, but some species are strictly monoga- 
mous. The ruminants are eminently polygamous, and they pre- 
sent sexual differences more frequently than almost any other 
group of mammals; this holds good, especially in their weapons, 
but also in other characters. Most deer, cattle, and sheep are 
polygamous; as are most antelopes, though seme are monoga- 
mous. Sir Andrew Smith, in speaking of the antelopes 
of South Africa, says that in herds of about a dozen there was 
rarely more than one m.ature male. The Asiatic Antilope saiga 
appears to be the most inordinate polygamist in the world; for 
Pallas" states that the m.ale drives away all rivals, and collects a 
herd of about a hundred females and kids together; the female 
is hornless and has softer hair, but does not otherwise differ much 
from the male. The wild horse of the Falkland Islands and of 
the Western States of North America is polygamous, but, except 
in his greater size and in the proportions of his body, differs but 
little from the mare. The wild boar presents well-marked sexual 
characters, in his great tusks and some other points. In Europe 
and in India he leads a solitary life, except during the breeding- 
season; but as is believed by Sir W. Elliot, who has had many 
opportunities in India of observing this animal, he consorts at 
this season with several females. Whether this holds good in 
Europe is doubtful, but is is supported by some evidence. The 
adult male Indian elephant, like the boar, passes much of his 
time in solitude; but as Dr. Campbell states, when with others, 
"it is rare to find more than one male with a whole herd of fe- 
"males;" the larger males expelling or killing the smaller and 
weaker ones. The male differs from the female in his immense 
tusks, greater size, strength, and endurance; so great is the dif- 
ference in these respects, that the males when caught are valued 
at one-fifth more than the females.^' The sexes of other pachy- 



10 On the Gorilla, Savage and Wyman. 'Boston Journal of Nat. Hist.' 
vol. V. 1845-47, p. 423. On Cynocephalus, Brehm, 'Illust, Thierleben,' 
B. i. 1864, s. 77. On Mycetes, Rengger, 'Naturgesch. : Saugethiere 
von Paraguay,' 1830, s. 14, 20. Cebus, Brehm, ibid. s. 108. 

" Pallas, 'Spicilegia Zoolog.,' Pasc. xii. 1777, p. 29. Sir Andrew 
Smith, 'Illustrations of the Zoology of S. Africa,' 1849, pi. 29, on the 
Kobus. Owen, in his 'Anatomy of Vertebrates' (vol. iii. 1868, p. 633) 
gives a table shov/ing incidentally which species of antelopes are gre- 
garious. 

^2 Dr. Campbell, in 'Proc. Zoolog. Soc' 1869, p. 138. See also an in- 
teresting paper, by Lieut. Johnstone, in 'Proc. Asiatic Soc. of Ben- 
gal,' May, 1868. 
15 



214 THE DESCENT OF MAN. 

dermatous animals differ very little or not at all, and, as far as 
known, they are not polygamists. Nor have I heard of any 
species in the Orders of Cheiroptera, Edentata, Insectivora and 
Rodents being polygamous, excepting that amongst the Rodents, 
the common rat, according to some rat-catchers, lives with several 
females. Nevertheless the two sexes of some sloths (Edentata) 
differ in the character and color of certain patches of hair on 
their shoulders." And many kinds of bats (Cheiroptera) present 
well-marked sexual differences, chiefly in the males possessing 
odoriferous glands and pouches, and by their being of a lighter 
color.^* In the great order of Rodents, as far as I can learn, 
the sexes rarely differ, and when they do so, it is but slightly in 
the tint of the fur. 

As I heard from Sir Andrew Smith, the lion in South Africa 
sometimes lives with a single female, but generally with more, 
and, in one case, was found with as many as five females; so that 
he is polygamous. As far as I can discover, he is the only polyg- 
amist amongst all the terrestial Carnivora, and he alone pre- 
sents well-marked sexual characters. If, however, we turn to the 
marine Carnivora, as we shall hereafter see, the case is widely 
different, for many species of seals offer extraordinary sexual 
differences, and they are eminently polygamous. Thus, accord- 
ing to Peron, the male sea-elephant of the Southern Ocean always 
possesses several females, and the sea-lion of Porster is said to be 
surrounded by from twenty to thirty females. In the North, the 
male sea-bear of Steller is accompanied by even a greater number 
of females. It is an interesting fact, as Dr. Gill remarks,^' that in 
the monogamous species, "or those living in small communities, 
"there is little difference in size between the males and females; 
"in the social species, or rather those of which the males have 
"harems, the males are vastly larger than the females." 

Amongst birds, many species, the sexes of which differ greatly 
from each other, are certainly monogamous. In Great Britain 
we see well-marked sexual differences, for instance, in the wild- 
duck which pairs with a single female, the common blackbird, 
and the bullfinch which is said to pair for life. I am informed 
by Mr. Wallace that the like is true of the Chatterers or Cot- 
ingidse of South America, and of many other birds. In several 
groups I have not been able to discover whether the species are 
polygamous or monogamous. Lesson says that birds of paradise, 
so remarkable for their sexual differences, are polygamous, but 
Mr. Wallace doubts whether he had sufficient evidence. Mr. Sal- 
vin tells me he has been led to believe that humming-birds are 
polygamous. The male widow-bird, remarkable for his caudal 

"Dr. Gray, in 'Annals and Mag. of Nat. Hist.' 1871, p. 302. 

" See Dr. Dobson's excellent paper, in 'Proc. Zoolog. Soc' 1873, p. 241. 

^5 The Eared Seals, 'American Naturalist,' vol. iv., Jan. 1871. 



Sexual selection. 215 

plumes, certainly seems to be a polygamist.^^ I have been as- 
sured by Mr. Jenner Weir and by others, that it is somewhat 
common for three starlings to frequent the same nest; but 
whether this is a case of polygamy or polyandry has not been 
ascertained. 

The Gallinacese exhibit almost as strongly marked sexual dif- 
ferences as birds of paradise or humming-birds, and many of the 
species are, as is well known, polygamous; others being strictly 
monogamous. ¥7hat a contrast is presented between the sexes 
of the polygamous peacock or pheasant, and the monogamous 
guinea-fowl or partridge! Many similar cases could be given, 
as in the grouse tribe, in which the males of the polygamous 
capercailzie and black-cock differ greatly from the females; whilst 
the sexes of the monogamous red grouse and ptarmigan differ 
very little. In the Cursores, except amongst the bustards, few 
species offer strongly-marked sexual differences, and the great 
bustard (Otis tarda) is said to be polygamous. With the Gralla- 
tores, extremely few species differ sexually, but the ruff (Machetes 
pugnax) affords a marked exception, and this species is believed 
by Montagu to be a polygamist. Hence it appears that amongst 
birds there often exists a close relation between polygamy and 
the development of strongly-marked sexual differences. I asked 
Mr. Bartlett, of the Zoological Gardens, who has had very large 
experience with birds, whether the male tragopan (one of the 
Gallinacese) was polygamous, and I was struck by his answering, 
"I do not knov/, but should think so from his splendid colors." 

It deserves notice that the instinct of pairing with a single fe- 
male is easily lost under domestication. The wild-duck is strictly 
monogamus, the domestic-duck highly polygamous. The Rev. 
W. D. Fox informs me that out of some half-tamed wild-ducks, 
on a large pond in his neighborhood, so many mallards were shot 
by the gamekeeper that only one was left for every seven or 
eight females; yet unusually large broods were reared. The 
guinea-fowl is strictly monogamous; but Mr. Fox finds that his 
birds succeed best when he keeps one cock to tv/o or three hens. 
Canary-birds pair in a state of nature, but the breeders in Eng- 
land successfully put one male to four or five females. I have 
noticed these cases, as rendering it probable that wild monog- 
amous species might readily become either temporarily or per- 
manently polygamous. 

Too little is known of the habits of reptiles and fishes to en- 



18 'The Ibis,' vol. iii. 1861, p. 133, on the Progne Widow-bird. See 
also on the Vidua axillaris, ibid. vol. ii. 1860, p. 211. On the polyg-amy 
of the Capercailzie and Great Bustard, see L. Lloyd, 'Game Birds of 
Sweden,' 1867, p. 19, and 182. Montag-u and Selby speak of the Black 
Grouse as polygamous and of the Red Grouse as monogamous. 



216 THE DESCENT OF MAN. 

able us to speak of their marriage arrangements. The stickle- 
back (Gasterosteus), however, is said to be a polygamist;'^ and 
the male during the breeding season differs conspicuously from 
the female. 

To sum up on the means through which, as far as we can judge, 
sexual selection has led to the development of secondary sexual 
characters. It has been shown that the largest number of vig- 
orous offspring will be reared from the pairing of the strongest 
and best-armed males, victorious in contests over other males, 
with the most vigorous and best-nourished females, which are 
the first to breed in the spring. If such females select the more 
attractive, and at the same time vigorous males, they will rear a 
larger number of offspring than the retarded females, which must 
pair with the less vigorous and less attractive males. So it will 
be if the more vigorous males select the more attractive and at 
the same time healthy and vigorous females; and this will es- 
pecially hold good if the male defends the female, and aids in pro- 
viding food for the young. The advantage thus gained by the 
more vigorous pairs in rearing a larger number of offspring has 
apparently sufficed to render sexual selection efficient. But a 
large numerical preponderance of males over females will be still 
more efficient; whether the preponderance is only occasional and 
local, or permanent; whether it occurs at birth, or afterwards 
from the greater destruction of the females; or whether it in- 
directly follows from the practice of polygamy. 

The Male generally more modified than the Female. — Through- 
out the animal kingdom, when the sexes differ in external appear- 
ance, it is, with rare exceptions, the male which has been the 
more modified; for, generally, the female retains a closer resem- 
blance to the young of her own species, and to other adult mem- 
bers of the same group. The cause of this seems to lie in the 
males of almost all animals having stronger passions than the fe- 
males. Hence it is the males that fight together and sedulously 
display their charms before the females; and the victors transmit 
their superiority to their male offspring. Why both sexes do not 
thus acquire the characters of their fathers, will be considered 
hereafter. That the males of all mammals eagerly pursue the fe- 
males is notorious to every one. So it is with birds; but many 
cock birds do not so much pursue the hen, as display their plum- 
age, perform strange antics, and pour forth their song in her 
presence. The male in the few fish observed seems much more 
eager than the female; and the same is true of alligators, and 
apparently of Batrachians. Throughout the enormous class of in- 

" No€l Humphreys, 'River Gardens,' 1857. 



SEXUAL SELECTION. 217 

sects, as Kirby remarks/* "the law is, that the male shall seek 
"the female." Two good authorities, Mr. BlackwaTl and Mr. C. 
Spence Bate, tell me that the males of spiders and crustaceans 
are more active aiid more erratic in their habits than the female's. 
When the organs of sense or locomotion are present in the one 
sex of insects and crustaceans and absent in the other, or when, 
as is frequently the case, they are more highly developed in the 
one than in the other, it is, as far as I can discover, almost in- 
variably the male which retains such organs, or has them most 
developed; and this shows that the male is the more active mem- 
ber in the courtship of the sexes." 

The female, on the other hand, with the rarest exceptions, is 
less eager than the male. As the illustrious Hunter-° long ago 
observed, she generally "requires to be courted;" she is coy, and 
may often be seen endeavoring for a long time to escape from the 
male. Every observer of the habits of animals will be able to call 
to mind instances of this kind. It is shown by various facts, 
given hereafter, and by the results fairly attributable to sexual 
selection, that the female, though comparatively passive, generally 
exerts some choice and accepts one male in preference to others. 
Or she may accept, as appearances would sometimes lead us to 
believe, not the male which is the most attractive to her, but 
the one which is the least distasteful. The exertion of some 
choice on the part of the female seems a law almost as general 
as the eagerness of the male. 

We are naturally led to inquire why the male, in so many and 
such distinct classes, has become more eager than the female, so 
that he searches for her, and plays the more active part in court- 
ship. It would be no advantage and some loss of power if each 
sex searched for the other; but why should the male almost 
always be the seeker? The ovules of plants after fertilization 
have to be nourished for a time; hence the pollen is necessarily 
brought to the female organs — being placed on the stigma, by 
means of insects or the wind, or by the spontaneous movements 

18 Kirby and Spence, 'Introduction to Entomology,' vol. iii. 1826, p. 
342. 

19 One parasitic Hymenopterous insect (Westwood, 'Modern Class, 
of Insects,' vol. ii. p. 160) forms an exception to the rule, as the male 
has rudimentary Vv^ings, and never quits the cell in which it is born, 
whilst the female has well-developed wing-s. Audouin believes that 
the females of this species are impregnated by the males which are 
born in the same cells with them; but it is much more probable that 
the females visit other cells, so that close interbreeding is thus 
avoided. We shall hereafter meet in various classes, with a few ex- 
ceptional cases, in which the female, instead of the male, is the 
seeker and wooer. 

20 'Essays and Observations,' edited by Owen, vol. i. 1861, p. 194, 



218 THE DESCENT OF MAN. 

of the stamens; and in the Algse, &c., by the locomotive power 
of the antherozooids. With lowly-organized aquatic animals, 
permanently affixed to the same spot and having their sexes sep- 
arate, the male element is invariably brought to the female; and 
of this we can see the reason, for even if the ova were detached 
before fertilization, and did not require subsequent nourishment or 
protection, there would yet be greater difficulty in transporting 
them than the male element, because being larger than the latter, 
they are produced in far smaller numbers. So that many of the 
lower animals are, in this respect, analogous with plants.^^ The 
male of affixed and aquatic animals having been led to emit 
their fertilizing element in this way, it is natural that any of 
their descendants, which rose in the scale and became locomotive, 
should retain the same habit; and they would approach the female 
as closely as possible, in order not to risk the loss of the fertiliz- 
ing element in a long passage of it through the water. With some 
few of the lower animals, the females alone are fixed, and the 
males of these must be the seekers. But it is difficult to under- 
stand why the males of species, of which the progenitors were 
primordially free, should invariably have acquired the habit of 
approaching the females, instead of being approached by them. 
But in all cases, in order that the males should seek efficiently, 
it would be necessary that they should be endowed with strong 
passions; and the acquirement of such passions would naturally 
follow from the more eager leaving a larger number of offspring 
than the less eager. 

The great eagerness of the males has thus indirectly led to their 
much more frequently developing secondary sexual characters 
than the females. But the development of such characters would 
be much aided, if the males were more liable to vary than the 
females— as I concluded they were— after a long study of domes- 
ticated animals. Von Nathusius, who has had very wide experi- 
ence, is strongly of the same opinion.^^ Good evidence also in 
favor of this conclusion can be produced by a comparison of 
the two sexes in m.ankind. During the Novara Expedition^'' a 
vast number of measurements was made of various parts of the 
body in different races, and the men were found in almost every 



21 Prof. Sachs C'Lehrbuch der Botanik,' 1870, s. 633) in speaking of 
the male and female reproductive cells, remarks, "verhalt sich die 
"eine bei der Vereinigung activ, ... die andere erscheint bei der 
Vereinigung passiv." 

22 'Vortrage uber Viehzucht,' 1872, p. 63. 

23 'Reise der Novara: Anthropolog-. Theil,' 1867, s. 216-269. The re- 
sults were calculated by Dr. Weisbach from measurements made by 
Drs. K. Scherzer and Schwarz. On the greater variability of the 
males of domesticated animals, see my 'Variation of Animals and 
Plants under Domestication,' vol. ii. 1868, p. 75. 



SEXUAL. SELECTION. 219 

case to present a greater range of variation than the women; but 
I shall have to recur to this subject in a future chapter. Mr. J. 
Wood,-^ who has carefullj^ attended to the variation of the muscles 
in man, puts in italics the conclusion that "the greatest number 
"of abnormalities in each subject is found in the males." He 
had previously remarked that "altogether in 102 subjects, the 
"varieties of redundancy were found to be half as many again as 
"in females, contrasting widely with the greater frequency of 
"deficiency in females before described." Professor Macalister 
likewise remarks-^ that variations in the muscles "are probably 
"more common in males than females." Certain muscles, which 
are not normally present in mankind are also more frequently 
developed in the male than in the female sex, although exceptions 
to this rule are said to occur. Dr. Burt Wilder-^ has tabulated the 
cases of 152 individuals with supernumerary digits, of which 86 
were males, and 89, or less than half, females, the remaining 27 
being of unknown sex. It should not, however, be overlooked 
that women would more frequently endeavor to conceal a de- 
formity of this kind than men. Again, Dr. L. Meyer asserts that 
the ears of man are more variable in form than those of woman.^^ 
Lastly the temperature is more variable in man than in woman.^ 
The cause of the greater general variability in the male sex, 
than in the female is unknown, except in so far as secondary 
sexual characters are extraordinarily variable, and are usually 
confined to the males; and, as we shall presently see, this fact is, 
to a certain extent, intelligible. Through the action of sexual 
and natural selection male animals have been rendered in very 
many instances widely different from their females; but in- 
dependently of selection the two sexes, from differing constitu- 
tionally, tend to vary in a somewhat different manner. The fe- 
male has to expend much organic matter in the formation of her 
ova, whereas the male expends much force in fierce contests with 
his rivals, in wandering about in search of the female, in exert- 
ing his voice, pouring out odoriferous secretions, &c.: and this 
expenditure is generally concentrated within a short period. The 
great vigor of the male during the season of love seems often to 
intensify his colors, independently of any marked difference 
from the female.^ In mankind, and even as lov/ down in the 



2^ 'Proceeding's Royal See' vol. xvl. July 1868, pp. 519 and 524. 

25 'Proc. Royal Irish Academy,' vol. x. 1868, p. 123. 

-" 'Massachusetts Medical Soc' vol. ii. No. 3, 1868, p. 9. 

27 'Archiv fur Path. Anat. und Phys.' 1871, p. 488. 

^ The conclusions recently arrived at by Dr. J. Stockton Hough, 
on the temperature of man, are given in the 'Pop. Science Review,' 
Jan. 1st, 1874 p. 97. 

29 Prof. Manteg-azza is inclined to believe ('Lettera a Carlo Darwin,' 
'Archivip per I'Anthropologia,' 1871, p. 306) that the bright colors, 



220 THE DESCENT OF MAN. 

organic scale as in the Lepidoptera, the temperature of the body 
is higher in the male than in the female, accompanied in the case 
of man by a slower pulse.^° On the whole the expenditure of 
matter and force by the two sexes is probably nearly equal, though 
effected in very different ways and at different rates. 

From the causes just specified the tv/o sexes can hardly fail to 
differ somewhat in constitution, at least during the breeding 
season: and, although they may be subjected to exactly the same 
conditions, thej'' will tend to vary in a different manner. If such 
variations are of no service to either sex, they will not be accu- 
mulated and increased by sexual or natural selection. Neverthe- 
less, they may become permanent if the exciting cause acts per- 
manently; and in accordance with a frequent form of inhsritance 
fhey may be transmitted to that sex alone in vtrhich they first 
appeared. In this case the two sexes will come to present perma- 
nent, yet unimportant, differences of character. For instance, 
Mr. Allen shows that with a large number of birds inhabiting the 
northern and southern United States, the specimens from the 
south are darker-colored than those from the north; and this 
seems to be the direct result of the difference in temperature, 
light, ScQ,., between the two regions. Now, in some few cases, the 
two sexes of the same species appear to have been differently af- 
fected; in the Agelseus phceniceus the males have had their colors 
greatly intensified in the south; whereas with Cardinalis virgin- 
ianus it is the females which have been thus affected; with Quis- 
caius major the females have been rendered extremely variable in 
tint, whilst the males remain nearly uniform.^^ 

A fev/ exceptional cases occur in various classes of animals, in 
which the females instead of the males have acquired well pro- 
nounced secondary sexual characters, such as brighter colors, 
greater size, strength, or pugnacity. With birds there has some- 
times been a complete transposition of the ordinary characters 
proper to each sex; the females having become the more eager in 
courtship, the males remaining comparatively passive, but ap- 
parently selecting the more attractive females, as v/e may infer 
from the results. Certain hen birds have thus been rendered 
more highly colored or otherwise ornamented, as well as more 

common in so many male animals, are due to the presence and re- 
tention by them of the spermatic fluid; but this can hardly be the 
case; for many male birds, for instance young- pheasants, become 
brig^htly colored in the autumn of their first year. 

^^ For mankind, see Dr. J. Stockton Houg-h, whose conclusions are 
given in the 'Pop. Science Review,' 1874, p. 97. See Girard's observa- 
tions on the Lepidoptera, as given in the 'Zoological Record,' 1869, p. 
347. 

31 'Mammals and Birds of E. Florida,' pp. 234, 280, 295. 



SEXUAL SELECTION. 221 

powerful and pugnacious than the cocks; these charact»ers being 
transmitted to the female offspring alone. 

It may be suggested that in some cases a double process of se^.; 
lection has been carried on; that the males have selected the' 
more attractive females, and the latter the more attractive males. 
This process, however, though it might lead to the modification of . 
both sexes, would not make the one sex different from the other,-^^ 
unless indeed their tastes for the beautiful differed; but this is a 
supposition too improbable to be worth considering in the case of 
any animal, excepting man. There are, however, many animals 
in which the sexes resemble each other, both being furnished with 
the same ornaments, which analogy would lead us to attribute to 
the agency of sexual selection. In such cases it may be suggested 
with more plausibility, that there has been a double or mutual 
process of sexual selection; the more vigorous and precocious fe- 
males selecting the more attractive and vigorous males, the latter 
rejecting all except the more attractive females. But from what 
we knov/ of the habits of animals, this view is hardly probable, 
for the male is generally eager to pair with any female. It is 
more probable that the ornaments common to both sexes were 
acquired by one sex, generally the male, and then transmitted to 
the offspring of both sexes. If, indeed, during a lengthened period 
the males of any species were greatly to exceed the females in 
number, and then during another lengthened period, but under 
different conditions, the reverse were to occur, a double, but not 
simultaneous, process of sexual selection might easily be carried 
on, by which the two sexes might be rendered widely different. 

We shall hereafter see that many animals exist, of which neither 
sex is brilliantly colored or provided with special ornaments, and 
yet the members of both sexes or of one alone have probably ac- 
quired simple colors, such as white or black, through sexual selec- 
tion. The absence of bright tints or other ornaments may be the 
result of variations of the right kind never having occurred, or of 
the animals themselves having preferred plain black or white. 
Obscure tints have often been developed through natural selection 
for the sake of protection, and the acquirement through sexual 
selection of conspicuous colors, appears to have been sometimes 
checked from the danger thus incurred. But in other cases the 
males during long ages may have struggled together for the pos- 
session of the females, and yet no effect v/ill have been produced, 
unless a larger number of offspring were left by the more success- 
ful males to inherit their superiority, than by the less successful; 
and this, as previously shown, depends on many complex contin- 
gencies. 

Sexual selection acts in a less rigorous manner than natural se- 
lection. The latter produces its effects by the life or death at all 
ages of the more or less successful individuals. Death, indeed. 



222 THE DESCENT OF MAN. 

not rarely ensues from the conflicts of rival males. But generally 
the less successful male merely fails to obtain a female, or obtains 
a retarded and less vigorous female later in the season, or, if polyg- 
amous, obtains fewer females; so that they leave fewer, less vig- 
orous, or no offspring. In regard to structures acquired through 
ordinary or natural selection, there is in most cases, as long as the 
conditions of life remain the same, a limit to the amount of ad- 
vantageous modification in relation to certain special purposes; 
but in regard to structures adapted to make one male victorious 
over another, either in fighting or in charming the female, there 
is no definite limit to the amount of advantageous modification; 
so that as long as the proper variations arise the work of sexual 
selection will go on. This circumstance may partly account for 
tTie frequent and extraordinary amount of variability presented 
by secondary sexual characters. Nevertheless, natural selection 
will determine that such characters shall not be acquired by the 
victorious males, if they would be highly injurious, either by ex- 
pending too much of their vital powers, or by exposing them to 
any great danger. The development, however, of certain struct- 
ures — of the horns, for instance, in certain stags — has been car- 
ried to a wonderful extreme; and in some cases to an extreme 
which, as far as the general conditions of life are concerned, must 
be slightly Injurious to the male. From this fact we learn that the 
advantages which favored males derive from conquering other 
males in battle or courtship, and thus leaving a numerous prog- 
eny, are in the long run greater than those derived from rather 
more perfect adaptation to their conditions of life. We shall fur- 
ther see, and it could never have been anticipated, that the power 
to charm the female has sometimes been more important than the 
power to conquer other males in battle. 

LAWS OF INHERITANCE. 

In order to understand how sexual selection has acted on many 
animals of many classes, and in the course of ages has produced 
a conspicuous result, it is necessary to bear in mind the laws of 
inheritance, as far as they are known. Two distinct elements 
are included under the term "inheritance"— the transmission, 
and the development of characters; but as these generally go 
together, the distinction is often overlooked. We see this dis- 
tinction in those characters which are transmitted through the 
early years of life, but are developed only at maturity or during 
old age. We see the same distinction more clearly with secondary 
sexual characters, for these are transmitted through both sexes, 
though developed in one alone. That they are present in both 
sexes, is manifest when two species, having strongly-marked sex- 
ual characters, are crossed, for each transmits the characters prop- 



SEXUAL SELECTION. 223 

er to its own male and female sex to the hybrid offspring of either 
sex. The same fact is likewise manifest, when characters proper 
to the male are occasionally developed in the female when she 
grows old or becomes diseased, as, for instance, when the com- 
mon hen assumes the flowing tail-feathers, hackles, comb, spurs, 
voice, and even pugnacity of the cock. Conversely, the same thing 
is evident, more or less plainly, with castrated males. Again, 
independently of old age or disease, characters are occasionally 
transferred from the male to the female, as when, in certain breeds 
of the fowls, spurs regularly appear in the young and healthy fe- 
males. But in truth they are simply developed in the female; for 
in every breed each detail in the structure of the spur is trans- 
mitted through the female to her male offspring. Many cases will 
hereafter be given, where the female exhibits, more or less per- 
fectly, characters proper to the male, in whom they must have 
been first developed, and then transferred to the female. The 
converse case of the first development of characters in the female 
iind of transference to the male, is less frequent; it will therefore 
be well to give one striking instance. With bees the pollen-col- 
lecting apparatus is used by the female alone for gathering pollen 
for the larvae, yet in most of the species it is partially developed in 
the males to whom it is quite useless, and it is perfectly developed 
in the males of Bombus or the humble-bee.^^ As not a single other 
Hymenopterous insect, not even the v/asp, which is closely allied 
to the bee, is provided with a pollen-collecting apparatus, we have 
no grounds for supposing that male bees primordially collected 
pollen as well as the females; although we have some reason to 
suspect that male mammals primordially suckled their young as 
well as the females. Lastly, in all cases of reversion, characters 
are transmitted through two, three, or many more generations, and 
are then developed under certain unknown favorable conditions. 
This important distinction between transmission and development 
will be best kept in mind by the aid of the hypothesis of pangen» 
esis. According to this hypothesis, every unit or cell of the body 
throws off gemmules or undeveloped atoms, which are transmitted 
to the offspring of both sexes, and are multiplied by self-division. 
They may remain undeveloped during the early years of life or 
during successive generations; and their development into units 
or cells, like those from which they were derived, depends on their 
affinity for, and union with other units or cells previously devel- 
oped in the due order of growth. 

Inheritance at corresponding Periods of Life. — This tendency is 
well established. A new character, appearing in a young animal, 

'"• M. Muller, 'Anwendung der Darwin'schen Lehre,' &c. Verh. i. n. 
■^ Jahrs, xxix. p. 42. 



224 '-THE DESCENT OF MAN. 

whether it lasts throughout life or is only transient, will, in gen- 
eral, reappear in the offspring at the same age and last for the 
same time. If, on the other hand, a new character appears at ma- 
turity, or even during old age, it tends to reappear in the offspring 
at the same advanced age. When deviations from this rule occur, 
the transmitted characters much oftener appear before, than after 
the corresponding age. As I have dwelt on this subject sufficiently 
in another workj^*^ I will here merely give two or three instances, 
for the sake of recalling the subject to the reader's mind. In sev- 
eral breeds of the Fowl, the down-covered chickens, the young 
bii-ds in their first true plumage, and the adults differ greatly from 
one another, as well as from their common parent-form, the Gal- 
lus bankiva; and these characters are faithfully transmitted by 
each breed to their offspring at the corresponding periods of life. 
For instance, the chickens of spangled Hamburgs, whilst covered 
with down, have a few dark spots on the head and rump, but are. 
not striped longitudinally, as in many other breeds; in their first 
true plumage, "they are beautifully pencilled," that is each feather 
is transversely marked by numerous dark bars; but in their second 
plumage the feathers all become spangled or tipped with a dark 
round spot."* Hence in this breed variations have occurred at, and 
been transmitted to, three distinct periods of life. The Pigeon of- 
fers a more remarkable case, because the aboriginal parent species 
does not undergo any change of plumage with advancing age, ex- 
cepting that at maturity the breast becomes more iridescent; yet 
there are breeds which do not acquire their characteristic colors 
until they have moulted two, three, or four times; and these 
modifications of plumage are regularly transmitted. 

InJieritance at corresponding Seasons of the Year. — With ani- 
mals in a state of nature, innumerable instances occur of charac- 
ters appearing periodically at different seasons. We see this in 
the horns of the stag, and in the fur of arctic animals which be- 
comes thick and white during the winter. Many birds acquire 
bright colors and other decorations during the breeding-season 
alone. Pallas states,^^ that in Siberia domestic cattle and horses 

33 'The Variation of Animals and Plants under Domestication,' vol. 
ii. 1868, p. 75. In the last chapter but one, the provisional hypothesis 
of pangenesis, above alluded to, is fully explained. 

3* These facts are given on the high authority of a great breeder, 
Mr. Teebay; see Tegetmeier's 'Poultry Book,' 1868, p. 158. On the 
characters of chickens of different breeds, and on the breeds of the 
pigeon, alluded to in the following paragraph, see 'Variation of Ani- 
mals,' &c., vol. i. pp. 160, 249; vol. ii. p. 77. 

35 'Novae species Quadrupedum e Glirium ordine,' 1778, p. 7. On 
the transmission of color by the horse, see 'Variation of Animals, 
&c., under Domestication,' vol. i. p. 51. Also vol. ii. p. 71, for a gen- 
eral discussion on 'Inheritance as limited by Sex.' 



SEXUAL SELECTION. 225 

become lighter-colored during the winter; and I have myself ob- 
served, and heard of similar strongly marked changes of color, 
that is, from brownish cream-color or reddish-brown to a perfect 
white in several ponies in England. Although I do not know that 
this tendency to change the color of the coat during different sea- 
sons is transmitted, yet it probably is so, as all shades of color are 
strongly inherited by the horse. Nor is this form of inheritance, 
as limited by the seasons, more remarkable than its limitation by 
age or sex. 

Inheritance as Limited by Sex. — The equal transmission of 
characters to both sexes is the commonest form of inheritance, at 
least with those animals which do not present strongly-marked 
sexual differences, and indeed with many of these. But characters 
are somewhat commonly transferred exclusively to that sex, in 
which they first appear. Ample evidence on this head has been 
advanced in my work on 'Variation under Domestication,' but a 
few instances may here be given. There are breeds of the sheep 
and goat, in which the horns of the male differ greatly in shape 
from those of the female; and these differences, acquired under 
domestication, are regularly transmitted to the same sex. As a 
rule, it is the females alone in cats which are tortoise-shell, the 
corresponding color in the males being rusty-red. With most 
breeds of the fowl, the characters proper to each sex are trans- 
mitted to the same sex alone. So general is this form of transmis- 
sion that it is an anomaly when variations in certain breeds are 
transmitted equally to both sexes. There are also certain sub- 
breeds of the fowl in which the males can hardly be distinguished 
from one another, whilst the females differ considerably in color. 
The sexes of the pigeon in the parent-species do not differ in any 
external character; nevertheless, in certain domesticated breeds 
the male is colored differently from the female.^" The wattle in the 
English Carrier pigeon, and the crop in the Pouter, are more 
highly developed in the male than in the female; and although 
these characters have been gained through long-continued selec- 
tion by man, the slight differences between the sexes are wholly 
due to the form of inheritance which has prevailed; for they have 
arisen, not from, but rather in opposition to, the wish of the 
breeder. 

Most of our domestic races have been formed by the accumula- 
tion of many slight variations: and as some of the successive steps 
have been transmitted to one sex alone, and some to both sexes, we 
find in the different breeds of the same species all gradations be- 

88 Dr. Chapuis, 'Le Pigeon "Voyageur Beige,' 1865, p. 87. Boitard et 
Corbie, 'Les Pigeons de Voliere,' &c., 1824, p. 173. See, also, on sim- 
ilar differences in certain breeds at Modena, 'Le variazioni del Col- 
ombi domestici,' del Paolo Bonizzi, 1873. 
16 



226 THE DESCENT OP MAN. 

tween great sexual dissimilarity and complete similarity. In- 
stances have already been given with the breeds of the fowl and 
pigeon, and under nature analogous cases are common. With 
animals under domestication, but whether in nature I will not 
venture to say, one sex may lose characters proper to it, and may 
thus come somewhat to resemble the opposite sex; for instance, 
the males of some breeds of the fowl have lost their masculine tail- 
plumes and hackles. On the other hand, the differences betv/een 
the sexes may be increased under domestication, as with merino 
sheep, in which the ewes have lost their horns. Again, characters 
proper to one sex may suddenly appear in the other sex; as in those 
sub-breeds of the fowl in which the hens acquire spurs whilst 
young; or, as in certain Polish sub-breeds, in which the females, 
as there is reason to believe, originally acquired a crest, and sub- 
sequently transferred it to the males. All these cases are intelli- 
gible on the hypothesis of pangenesis; for they depend on the 
gemmules of certain parts, although present in both sexes, becom- 
ing, through the influence of domestication, either dormant or de- 
veloped in either sex. 

There is one difficult question which it will be convenient to 
defer to a future chapter; namely, whether a character at first de- 
veloped in both sexes, could through selection be limited in its de- 
velopment to one sex alone. If, for instance, a breeder observed 
that some of his pigeons (of which the characters are usually 
transferred in an equal degree to both sexes) varied into pale blue, 
could he by long-continued selection make a breed in which the 
males alone should be of this tint, whilst the females remained 
unchanged? I will here only say, that this, though perhaps not 
impossible, would be extremely difficult; for the natural result of 
breeding from the pale-blue males would be to change the whole 
stock of both sexes to this tint. If, however, variations of the de- 
sired tint appeared, which were from the first limited in their 
development to the male sex, there would not be the least dif- 
ficulty in making a breed with the two sexes of a different color, 
as indeed has been effected with a Belgian breed, in which the 
males alone are streaked with black. In a similar manner, if any 
variation appeared in a female pigeon, which was from the first 
sexually limited in its development to the females, it would be 
easy to make a breed with the females alone thus characterized; 
but if the variation was not thus originally limited, the process 
would be extremely difficult, perhaps impossible." 

3'^ Since the publication of the first edition of this work, it has been 
highly satisfactory to me to find the following remarks (the 'Field,' 
Sept. 1872) from so experienced a breeder as Mr. Tegetmeier. After 
describing some curious cases in pigeons, of the transmission of color 
by one sex alone, and the formation of a sub-breed with this char- 
acter, he says: "It is a singular circumstance that Mr. Darwin 



SEXUAL SELECTION. 227 



On the Relatimi between the Period of Development of a Character 
and its Transmission to one Sex or to both Sexes, — Why cer- 
tain characters should be inherited by both sexes, and other char- 
acters by one sex alone, namely by that sex in which the character 
first appeared, is in most cases quite unknown. We cannot even 
conjecture why with certain sub-breeds of the pigeon, black striae, 
though transmitted through the female, should be developed in the 
male alone, whilst every other character is equally transferred to 
both sexes. Why, again, with cats, the tortoise-shell color should, 
with rare exceptions, be developed in the female alone, 't'he very 
same character, such as deficient or supernumerary digits, color- 
blindness, &c., may with mankind be inherited by the males alone 
of one family, and in another family by the females alone, though 
in both cases transmitted through the opposite as well as through 
the same sex.^® Although we are thus ignorant, the two following 
rules seem often to hold good — that variations which first appear 
in either sex at a late period of life, tend to be developed in the 
same sex alone; whilst variations vv^hich first appear early in life 
in either sex tend to be developed in both sexes. I am, however, 
far from supposing that this is the sole determining cause. As I 
have not elsewhere discussed this subject, and as it has an impor- 
tant bearing on sexual selection, I must here enter into lengthy 
and somewhat intricate details. 

It is in itself probable that any character appearing at an early 
age would tend to be inherited equally by both sexes, for the sexes 
do not differ much in constitution before the power of reproduc- 
tion is gained. On the other hand, after this power has been 
gained and the sexes have come to differ in constitution, the gem- 
mules (if I may again use the language of pangenesis) which are 
cast off from each varying part in the one sex would be much more 
likely to possess the proper affinities for uniting with the tissues 
of the same sex, and thus becoming developed, than witli those of 
the opposite sex. 

I was first led to infer that a relation of this kind exists, from 
the fact that whenever and in whatever manner the adult male 
differs from the adult female, he differs in the same manner from 
the young of both sexes. The generality of this fact is quite re- 
markable: it holds good with almost all mammals, birds, amphib- 
ians, and fishes; also with many crustaceans, spiders, and some 
few insects, such as certain orthoptera and libellulae. In all these 

"should have sug-gested the possibility of modifying' the sexual colors 
"of birds by a course of artificial selection. When he did so, he was 
"in ignorance of these facts that I have related; but it is remarkable 
"how very closely he suggested the right method of procedure." 

ss References are given in my 'Variation of Animals under Domes- 
tication,' vol. ii. p. 72. 



22g THE DESCENT OF MAN. 

cases the variations, through the accumulation of which the male 
acquired his proper masculine characters, must have occurred at a 
somewhat late period of life; otherwise the young males would 
have been similarly characterized; and comformahly with our rule, 
the variations are transmitted to and developed in the adult males 
alone. When, on the other hand, the adult male closely resembles 
the young of both sexes (these, with rare exceptions, being alike), 
he generally resembles the adult female; and in most of these cases 
the variations through which the young and old acquired their 
present characters, probably occurred, according to our rule, dur- 
ing youth. But there is here room for doubt, for characters are 
sometimes transferred to the offspring at an earlier age than that 
at which they first appeared in the parents, so that the parents 
may have varied when adult, and have transferred their characters 
to their offspring whilst young. There are, moreover, many ani- 
mals, in which the two sexes closely resemble each other, and yet 
both differ from their young; and here the characters of the adults 
must have been acquired late in life; nevertheless, these char- 
acters, in apparent contradiction to our rule, are transferred to 
both sexes. We must not, however, overlook the possibility or 
even probability of successive variations of the same nature occur- 
ring, under exposure to similar conditions, simultaneously in both 
sexes at a rather late period of life; and in this case the variations 
would be transferred to the offspring of both sexes at a corre- 
sponding late age; and there would then be no real contradiction 
to the rule that variations occurring late in life are transferred 
exclusively to the sex in which they first appeared. This latter 
rule seems to hold true more generally than the second one, 
namely, that variations which occur in either sex early in life tend 
to be transferred to both sexes. As it was obviouslj^ impossible 
even to estimate in how large a number of cases throughout the 
animal kingdom these two propositions held good, it occurred to 
me to investigate some striking or crucial instances, and to rely 
on the result. 

An excellent case for investigation is afforded by the Deer 
family. In all the species, but one, the horns are developed only 
in the males, though certainly transmitted through the females, 
and capable of abnormal development in them. In the reindeer, 
on the other hand, the female is provided with horns; so that in 
this species, the horns ought, according to our rule, to appear early 
in life, long before the two sexes are mature and have come to dif- 
fer much in constitution. In all the other species the horns ought 
to appear later in life, which would lead to their development in 
that sex alone, in which they first appeared in the progenitor of 
the whole Family. Now in seven species, belonging to distinct 
sections of the family and inhabiting different regions, in which 
the stags alone bear horns, I find that the horns first appear at 



• SEXUAL SELECTION. 229 

periods, varying from nine monttis after birth in tlie roebuck, to 
ten, twelve or even more months in the stags of the six other 
and larger species.^^ But with the reindeer the case is widely dif- 
ferent; for, as I hear from Prof. Nilsson, who kindly made special 
inquiries for me in Lapland, the horns appear in the young ani- 
mals within four or five weeks after birth, and at the same time 
in both sexes. So that here we have a structure, developed at a 
most unusually early age in one species of the family, and like- 
wise common to both sexes in this one species alone. 

In several kinds of antelopes, only the males are provided with 
horns, whilst in the greater number both sexes bear horns. With 
respect to the period of development, Mr. Blyth informs me that 
there was at one time in the Zoological Gardens a young koodoo 
(Ant. strepsiceros), of which the males alone are horned, and also 
the young of a closely-allied species, the eland (Ant. oreas), in 
which both sexes are horned. Now it is in strict conformity with 
our rule, that in the young male koodoo, although ten months old, 
the horns were remarkably small, considering the size ultimately 
attained by them; whilst in the young male eland, although only 
three months old, the horns were already very much larger than 
in the koodoo. It is also a noticeable fact that in the prong-horned 
antelope,*" only a few of the females, about one in five, have horns 
and these are in a rudimentary state, though sometimes above four 
inches long; so that as far as concerns the possession of horns by 
the males alone, this species is in an intermediate condition, and 
the horns do not appear until about five or six months after birth. 
Therefore in comparison with what little we know of the develop- 
ment of the horns in other antelopes, and from what we do know 
with respect to the horns of deer, cattle, &c., those of the prong- 
horned antelope appear at an intermediate period of life,— that is, 
not very early, as in cattle and sheep, nor very late, as in the larg- 
er deer and antelopes. The horns of sheep, goats, and cattle, 
which are well developed in both sexes, though not quite equal in 



^^ I am much obliged to Mr. Cupples for having made inquiries 
for me in regard to the Roebuck and Red Deer of Scotland from Mr. 
Robertson, the experienced head-forester to the Marquis of Breadal- 
bane. In regard to Fallow-deer, I have to thank Mr. Eyton and 
others for information. For the Cervus aloes of N. America, see 
'Land and Water,' 1868, pp. 221 and 254; and for the C. Virginianus 
and strongyliceros of the same continent, see J. D. Caton, in 'Ottawa 
Acad, of Nat. Sc. 1868, p. 13. For Cervus Eldi of Pegu, see Lieut. 
Beavan, 'Proc. Zoolog. Soc* 1867, p. 762. 

^Antilocapra Americana. I have to thank Dr. Canfield for In- 
formation with respect to the horns of the female: see also his paper 
in 'Proc. Zoolog. Soc' 1866, p. 109. Also Owen. 'Anatomy of Verte- 
brates,' vol. iii. p. 627. 

16 



230 THE DESCENT OP MAN. 

size, can be felt, or even seen, at birth or soon afterwards.'^ Our 
rule, however, seems to fail in some breeds of sheep, for instance 
merinos, in which the rams alohe are horned; for I cannot find 
on inquiry,*^ that the horns are developed later in life in this 
breed than in ordinary sheep in which both sexes are horned. But 
with domesticated sheep the presence or absence of horns is not a 
firmly fixed character; for a certain proportion of the merino ewes 
bear small horns, and some of the rams are hornless; and in most 
breeds hornless ewes are occasionally produced. 

Dr. W. Marshall has lately made a special study of the protuber- 
ances so common on the heads of birds,*^ and he comes to the fol- 
lowing conclusion; — that with those species in which they are con- 
fined to the males, they are developed late in life; whereas with 
those species in which they are common to the two sexes, they are 
developed at a very early period. This is certainly a strildng con- 
firmation of my two laws of inheritance. 

In most of the species of the splendid family of the Pheasants, 
the males differ conspicuously from the females, and they acquire 
their ornaments at a rather late period of life. The eared pheas- 
ant (Crossoptilon auritum), however, offers a remarkable excep- 
tion, for both sexes possess the fine cau'''al plumes, the large ear- 
tufts and the crimson velvet about the head; I find that all these 
characters appear very early in life in accordance with rule. The 
adult male can, however, be distinguished from the adult female 
by the presence of spurs; and conformably with our rule, these do 
not begin to be developed before the age of six months, as I am 
assured by Mr. Bartlett, and even at this age, the two sexes can 
hardly be distinguished.^ The male and female Peacock differ 



*i I have been assured that the horns of the sheep in North Wales 
can always be felt, and are sometimes even an inch in length, at 
birth. Youatt says ('Cattle,' 1834, p. 277), that the prominence of the 
frontal bone in cattle penetrates the cutis at birth, and that the 
horny matter is soon formed over it. 

^ I am greatly indebted to Prof. Victor Carus for having made 
inquiries for me, from the highest authorities, with respect to the 
merino sheep of Saxony. On the Guinea coast of Africa there is, 
however, a breed of sheep in which, as with merinos, the rams alone 
bear horns; and Mr. Winwood Reade informs me that in one case 
observed by him, a young ram, born on Feb. 10th, first showed horns 
on March 6th, so that in this instance, in conformity with rule, the 
development of the horns occurred at a later period of life than in 
Welsh sheep, in which both sexes are horned, 

" 'Ueber die knochernen Schadelhocker der Vogel' in the 'Nieder- 
landischen Archiv fur Zoologie,' Band I. Heft 2, 1872. 

** In the common peacock (Pavo cristatus) the male alone possesses 
spurs, whilst both sexes of the Java Peacock (P. muticus) offer the 
unusual case of being furnished with spurs. Hence I fully expected 
that in the latter species they would have been developed earlier ic 



SEXUAL SELECTION. 231 

conspicuously from each other in almost every part of their plum- 
age, except in the elegant head-crest, which is common to both 
sexes; and this is developed very early in life, long before the other 
ornaments, which are confined to the male. The wild-duck offers 
an analogous case, for the beautiful green speculum on the wings 
is common to both sexes, though duller and somewhat smaller in 
the female, and it is developed early in life, v/hilst the curled tail- 
feathers and other ornaments of the male are developed later. *^ 
Between such extreme cases of close sexual resemblance and wide 
dissimilarity, as those of the Crossoptilon and peacock, many in- 
termediate ones could be given, in which the characters follow our 
two rules in their order of development. 

As most insects emerge from the pupal state in a mature con- 
dition, it is doubtful whether the period of development can deter- 
mine the transference of their characters to one or to both sexes. 
But we do not know that the colored scales, for instance, in two 
species of butterflies, in one of which the sexes differ in color, 
whilst in the other they are alike, are developed at the same rela- 
tive age in the cocoon. Nor do we know whether all the scales 
are simultaneously developed on the wings of the same species 
of butterfly, in which certain colored marks are confined to one 
sex, whilst others are common to both sexes. A difference of this 
kind in the period of development is not so improbable as it may 
at first appear; for with the Orthoptera, which assume their 
adult state, not by a single metamorphosis, but by a succession 
of moults, the young males of some species at first resemble the 
females, and acquire their distinctive masculine characters only 



life than in the common peacock; but M. Hogt of Amsterdam in- 
forms me, that with young birds of the previous year, of both species, 
compared on April 23rd, 1869, there was no difference in the develop- 
ment of the spurs. The spurs, however, were as yet represented 
merely by slight knobs or elevations. I presume that I should have 
been informed if any difference in the rate of development had been 
observed subsequently. 

*s In some other species of the Duck family the speculum differs 
In a greater degree in the two sexes; but I have not been able to 
discover whether its full development occurs later in life in the 
males of such species, than in the male of the common duck, as 
ought to be the case according to our rule. With the allied Mergus 
cucullatus we have, however, a case of this kind: the two sexes dif- 
fer conspicuously in general plumage, and to a considerable degree 
In the speculum, which is pure white in the male and grayish-white 
in the female. Now the young males at first entirely resemble the 
females, and have a grayish-white speculum, which becomes pure 
white at an earlier age than that at which the adult male acquires 
his other and more strongly-marked sexual differences: see Audu« 
bon, 'Ornithological Biography,' vol. iii. 1835, pp. 249-250. 



232 THE DESCENT OF MAN. 

at a later moult. Strictly analogous cases occur at the successive 
moults of certain male crustaceans. 

We have as yet considered the transference of characters, rela- 
tively to their period of development, only in species in a natural 
state; we will now turn to domesticated animals, and first toucn 
on monstrosities and diseases. The presence of supernumerary 
digits, and the absence of certain phalanges, must be determined 
at an early embryonic period — the tendency to profuse bleeding is 
at least congenital, as is probably color-blindness — yet these pe- 
culiarities, and other similar ones, are often limited in their trans- 
mission to one sex; so that the rule that characters, developed at 
an early period, tend to be transmitted to both sexes, here wholly 
fails. But this rule, as before remarked, does not appear to be 
nearly so general as the converse one, namely, that characters 
which appear late in life in one sex are transmitted exclusively to 
the same sex. From the fact of the above abnormal peculiarities 
becoming attached to one sex, long before the sexual functions are 
active, we may infer that there must be some difference between 
the sexes at an extremely early age. With respect to sexually lim- 
ited diseases, we know too little of the period at which they orig- 
inate, to draw any safe conclusion. Gout, however, seems to fall 
under our rule, for it is generally caused by intemperance during 
manhood, and is transmitted from the father to his sons in a 
much more marked manner than to his daughters. 

In the various domestic breeds of sheep, goats, and cattle, the 
males differ from their respective females in the shape or develop- 
ment of their horns, forehead, mane, dewlap, tail, and hump on 
the shoulders; and these peculiarities, in accordance with our 
rule, are not fully developed antil a rather late period of life. 
The sexes of dogs do not differ, except that in certain breeds, 
especially in the Scotch deer-hound, the male is much larger 
and heavier than the female; and, as we shall see in a future 
chapter, the male goes on increasing in size to an unusually late 
period of life, which, according to rule, will account for his in- 
creased size being transmitted to his male offspring alone. On 
the other hand, the tortoise-shell color, which is confined to 
female cats, is quite distinct at birth, and this case violates the 
rule. There is a breed of pigeons in which the males alone are 
streaked with black, and the streaks can be detected even in the 
nestlings; but they become more conspicuous at each successive 
moult, so that this case partly opposes and partly supports the 
rule. With the English Carrier and Pouter pigeons, the full de- 
velopment of the wattle and the crop occurs rather late in life, 
and conformably with the rule, these characters are transmitted 
in full perfection to the males alone. The following cases perhaps 
come within the class previously alluded to, in which both sexes 
have varied in the same manner at a rather late period of life, 



SEXUAL SELECTION. 233 

md have consequently transferred their new characters to both 
sexes at a corresponding late period; and if so, these cases are 
not opposed to our rule: — there exist sub-breeds of the pigeon, 
described by Neumeister,*^ in which both sexes change their color 
during two or three moults (as is likewise the case with the 
Almond Tumbler), nevertheless, these changes, though occurring 
rather late in life, are common to both sexes. One variety of the 
Canary-bird, namely the London Prize, offers a nearly analogous 
case. 

With the breeds of the Fowl the inheritance of various charac- 
ters by one or both sexes, seems generally determined by the 
period at which such characters are developed. Thus in all the 
many breeds in which the adult male differs greatly in color from 
the female, as well as from the wild parent-species, he differs 
also from the young male, so that the newly-acquired characters 
must have appeared at a rather late period of life. On the other 
hand, in most of the breeds in which the two sexes resemble each 
other, the young are colored in nearly the same manner as their 
parents, and this renders it probable that their colors first ap- 
peared early in life. We have instances of this fact in all black 
and white breeds, in which the young and old of both sexes are 
alike; nor can it be maintained that there is something peculiar 
in a black or white plumage, which leads to its transference to 
both sexes; for the males alone of many natural species are either 
black or white, the females being differently colored. With the 
so-called Cuckoo sub-breeds of the fowl, in which the feathers are 
transversely pencilled with dark stripes, both sexes and the chick- 
ens are colored in nearly the same manner. The laced plumage 
of the Sebright bantam is the same in both sexes, and in the young 
chickens the wing-feathers are distinctly, though imperfectly 
laced. Spangled Hamburgs, however, offer a partial exception; 
for the two sexes, though not quite alike, resemble each other 
more closely than do the sexes of the aboriginal parent-species; 
yet they acquire their characteristic plumage late in life, for the 
chickens are distinctly pencilled. With respect to other characters 
besides color, in the wild-parent species and in most of the domes- 
tic breeds, the males alone possess a well-developed comb; but in 
the young of the Spanish fowl it is largely developed at a very 
early age, and, in accordance with this early development in the 
male, it is of unusual size in the adult female. In the Game 
breeds, pugnacity is developed at a wonderfully early age, of 
which curious proofs could be given; and this character is trans- 
mitted to both sexes, so that the hens, from their extreme pug- 

*8 'Das Ganze der Taubenzucht,' 1837, s. 21, 24. For the case of the 
streaked pigeons, see Dr. Chapuis, 'Le pigeon voyageur Beige,' 1865, 
p. 87. 



234 THE DESCENT OF MAN. 

nacity, are now generally exhibited in separate pens. With the 
Polish breeds the bony protuberance of the skull which supports 
the crest is partially developed even before the chickens are 
hatched, and the crest itself soon begins to grow, though at first 
feebly ;^^ and in this breed the adults of both sexes are charac- 
terized by a great bony protuberance and an immense crest. 

Finally, from what we have now seen of the relation which 
exists in many natural species and domesticated races, between 
the period of the development of their characters and the manner 
of their transmission — for example, the striking fact of the early 
grov/th of the horns in the reindeer, in which both sexes bear 
horns, in comparison with their much later growth in the other 
species in which the male alone bears horns — we may conclude 
that one, though not the sole cause of characters being exclusively 
inherited by one sex, is their development at a late age. And 
secondly that one, though apparently a less efiicient cause of char- 
acters being inherited by both sexes, is their development at an 
early age, whilst the sexes differ but little in constitution. It 
appears, however, that some difference must exist between the 
sexes even during a very early embryonic period, for characters 
developed at this age not rarely become attached to one sex. 

Summary and concluding remarks. — From the foregoing dis- 
cussion on the various laws of inheritance, we learn that the 
characters of the parents often, or even generally, tend to become 
developed in the offspring of the same sex, at the same age, and 
periodically at the same season of the year, in which they first 
appeared in the parents. But these rules, owing to unknown 
causes, are far from being fixed. Hence during the modification 
of a species, the successive changes may readily be transmitted 
in different ways; some to one sex, and some to both; some to 
the offspring at one age, and some to the offspring at all ages. 
Not only are the laws of inheritance extremely complex, but so 
are the causes which induce and govern variability. The varia- 
tions thus induced are preserved and accumulated by sexual selec- 
tion, which is in itself an extremely complex affair, depending, as 
it does, on the ardor in love, the courage, and the rivalry of the 
males, as well as on the powers of perception, the taste, and will 
of the female. Sexual selection will also be largely dominated by 
natural selection tending towards the general welfare of the spe- 
cies. Hence the manner in which the individuals of either or both 



" For full particulars and references on all these points respecting- 
the several breeds of the Fowl, see 'Variation of Animals and Plants 
under Domestication,' vol. i. pp. 250, 256. In regard to the higher ani- 
mals, the sexual differences v/hich have arisen under domestication 
are described in the same work under the head of each species. 



SEXUAL SELECTION. 235 

sexes have been affected through sexual selection cannot fail to 
be complex in the highest degree. 

When variations occur late in life in one sex, and are trans- 
mitted to the same sex at the same age, the other sex and the 
young are left unmodified. When they occur late in life, but 
are transmitted to both sexes at the same age, the young alone 
are left unmodified. Variations, however, may occur at any period 
of life in one sex or in both, and be transmitted to both sexes 
at all ages, and then all the individuals of the species are sim- 
ilarly modified. In the following chapters it will be seen that all 
these cases frequently occur in nature. 

Sexual selection can never act on any animal before the age 
for reproduction arrives. From the great eagerness of the "male 
it has generally acted on this sex and not on the females. The 
males have thus become provided with weapons for fighting with 
their rivals, with organs for discovering and securely holding the 
female, and for exciting or charming her. V/hen the sexes differ 
in these respects, it is also, as we have seen, an extremely general 
law that the adult male differs more or less from the young male; 
and we may conclude from this fact that the successive variations, 
by which the adult male became modified, did not generally occur 
much before the age for reproduction. Whenever some or many 
of the variations occurred early in life, the young males would par- 
take more or less of the characters of the adult males; and dif- 
ferences of this kind between the old and young males may be 
observed in many species of animals. 

It is probable that young male animals have often tended to 
vary in a manner which would not only have been of no use to 
them at an early age, but would have been actually injurious — 
as by acquiring bright colors, which would render them con- 
spicuous to their enemies, or by acquiring structures, such as 
great horns, which would expend much vital force in their devel- 
opment. Variations of this kind occurring in the young males 
would almost certainly be eliminated through natural selection. 
With the adult and experienced males, on the other hand, the 
advantages derived from the acquisition of such characters, would 
more than counterbalance some exposure to danger, and some 
loss of vital force. 

As variations which give to the male a better chance of con- 
quering other males, or of finding, securing, or charming the oppo- 
site sex, would, if they happen to arise in the female, be of no 
service to her, they would not be preserved in her through sexual 
selection. We have also good evidence with domesticated ani- 
mals, that variations of all kinds are, if not carefully selected, 
soon lost through intercrossing and accidental deaths. Conse- 
quently in a state of nature, if variations of the above kind 
chanced to arise in the female line, and to be transmitted exclu- 



236 THE DESCENT OF MAN. 

sively in this line, they would be extremely liable to be lost. If, 
however, the females varied and submitted their newly acquired 
characters to their offsprings of both sexes, the characters which 
were advantageous to the males would be preserved by them 
through sexual selection, and the two sexes would in consequence 
be modified in the same manner, although such characters were 
of no use to the females; but I shall hereafter have to recur to 
these more intricate contingencies. Lastly, the females may ac- 
quire, and apparently have often acquired by transference, char- 
acters from the male sex. 

As variations occurring late in life, and transmitted to one sex 
alone, have incessantly been taken advantage of and accumulated 
through sexual selection in relation to the reproduction of the 
species; therefore it appears, at first sight, an unaccountable fact 
that similar variations have not frequently been accumulated 
through natural selection, in relation to the ordinary habits of life. 
If this had occurred, the two sexes would often have been differ- 
ently modified, for the sake, for instance, of capturing prey or of 
escaping from danger. Differences of this kind between the two 
sexes do occasionally occur, especially in the lower classes. But 
this implies that the two sexes follow different habits in their 
struggles for existence, which is a rare circumstance with the 
higher animals. The case, however, is widely different with the 
reproductive functions, in which respect the sexes necessarily dif- 
fer. For variations in structure which are related to these func- 
tions, have often proved of value to one sex, and from having 
arisen at a late period of life, have been transmitted to one sex 
alone; and such variations, thus preserved and transmitted, 
have given rise to secondary sexual characters. 

In the following chapters, I shall treat of the secondary sexual 
characters in animals of all classes, and shall endeavor in each 
case to apply the principles explained in the present chapter. The 
lowest classes will detain us for a very short time, but the higher 
animals, especially birds, must be treated at considerable length. 
It should be borne in mind that for reasons already assigned, I 
intend to give only a few illustrative instances of the innumerable 
structures by the aid of which the male finds the female, or when 
found, holds her. On the other hand, all structures and instincts 
by the aid of which the male conquers other males, and by whicn 
he allures or excites the female, will be fully discussed, as these 
are in many ways the most interesting. 



Supplement on the proportional numbers of the two sexes in an- 
imals belonging to various classes 

As no one, as far as I can discover, has paid attention to the 
relative numbers of the two sexes throughout the animal king- 



PROPORTION OF THE SEXES. 237 

dom, I will here give such materials as I have been able to collect, 
althougli tliey are extremely imperfect. They consist in only a 
few instances of actual enumeration, and the numbers are not 
very large. As the proportions are known with certainty only in 
mankind, I will first give them as a standard of comparison. 

Man. — In England during ten years (from 1857 to 1866) the 
average number of children born alive yearly was 707,120, in 
the proportion of 104.5 males to 100 females. But in 1857 the 
male births throughout England were as 105.2 and in 1865 as 
104.0 to 100. Looking to separate districts, in Buckinghamshire 
(where about 5000 children are annually born) the mean propor- 
tion of male to female births, during the whole period of the above 
ten years was as 102.8 to 100; whilst in N. Wales (where the 
average annual births are 12,873) it was as high as 106.2 to 100. 
Taking a still smaller district, viz., Rutlandshire (where the 
annual births average only 739), in 1864 the male births were as 
114.6, and in 1862 as only 97.0 to 100; but even in this small dis- 
trict the average of the 7385 births during the whole ten years, 
was as 104.5 to 100; that is in the same ratio as throughout Eng- 
land.^ The proportions are sometimes slightly disturbed by un- 
known causes; thus Prof. Faye states "that in some districts of 
"Norway there has been during a decennial period a steady de- 
"ficiency of boys, whilst in others the opposite condition has 
"existed." In Prance during forty-four years the male to the 
female births have been as 106.2 to 100; but during this period 
it has occurred five times in one department, and six times in. 
another, that the female births have exceeded the males. In 
Russia the average proportion is as high as 108.9, and in Phila- 
delphia in the United States as 110.5 to 100."^ The average for 
Europe, deduced by Bickes from about seventy million births, 
is 106 males to 100 females. On the other hand, with white chil- 
dren born at the Cape of Good Hope, the proportion of males is so 
low as to fluctuate during successive years between 90 and 99 
males for every 100 females. It is a singular fact that with Jews 
the proportion of male births is decidedly larger than with Chris- 
tians: thus in Prussia the proportion is as 113, in Breslau as 
114, and in Livonia as 120 to 100; the Christian births in these 

*8 'Twenty-ninth Annual Report of the Registrar-General for 1866.' 
In this report (p. xii.) a special decennial table is given. 

*9 For Norway and Russia, see abstract of Prof. Faye's reseai*ches, 
in 'British and Foreign Medico-Chirurg. Review,' April, 1867, pp. 343, 
345. For France, the 'Annuaire pour I'An 1867,' p. 213. For Philadel- 
phia, Dr. Stockton-Hough, 'Social Science Assoc' 1874. For the Cape 
of Good Hope, Quetelet as quoted by Dr. H. H. Zouteveen, in the 
Dutch Translation of this work (vol. i. p. 417), where much informa- 
tion is given on the proportion of the sexes. 



238 THE DESCENT OF MAN. 

countries being the same as usual, for instance, in Livonia as 104 
to 100.^° 

Prof. Faye remarks that "a still greater preponderance of males 
"would be met with, if death struck both sexes in equal pro- 
"portion in the womb and during birth. But the fact is, that for 
"every 100 still-born females, we have in several countries from 
"134.6 to 144.9 still-born males. During the first four or five years 
"of life, also, more male children die than females; for example 
"in England, during the first year, 126 boys die for every 100 
"girls— a proportion which in France is still more unfavorable."" 
Dr. Stockton-Hough accounts for these facts in part by the more 
frequent defective development of males than of females. We 
have before seen that the male sex is more variable iii structure 
than the female; and variations in important organs would gen- 
erally be injurious. But the size of the body, and especially of the 
head, being greater in male than female infants is another cause; 
for the males are thus more liable to be injured during parturition. 
Consequently the still-born males are more numerous; and, as a 
highly competent judge. Dr. Crichton Browne,'^ believes, male in- 
fants often suffer in health for some years after birth. Owing to 
this excess in the death-rate of male children, both at birth and 
for some time subsequently, and owing to the exposure of grown 
men to various dangers, and to their tendency to emigrate, the 
females in all old-settled countries, where statistical records have 
been kept,^^ are found to preponderate considerably over the males. 

It seems at first sight a mysterious fact that in different na- 
tions, under different conditions and climates, in Naples, Prussia, 
Westphalia, Holland, France, England and the United States, the 

^0 In regard to the Jews, see M. Tliury, 'La Loi de Production des 
Sexes,' 1863, p. 25. 

51 'British and Foreign Medico-Chirurg. Review,' April, 1867, p. 343. 
Dr. Stark also remarks ('Tenth Annual Report of Births, Deaths, 
&c., in Scotland,' 1867, p. xxviii.) that "These examples maj^ suffice 
"to show that, at almost every stage of life, the males in ,Scotland 
"have a greater liability to death and a higher death-rate than the 
"females. The fact, however, of this peculiarity being most strongly 
"developed at that infantile period of life when the dress, food, and 
"general treatment of both sexes are alike, seems to prove that the 
"higher male death-rate is an impressed, natural, and constitutional 
"peculiarity due to sex alone." 

52 'West Riding Lunatic Asylum Reports,' vol. i. 1871, p. 8. Sir J. 
Simpson has proved that the head of the male infant exceeds that 
of the female by 3-8ths of an inch in circumference, and by l-8th in 
transverse diameter. Quetelet has shown that woman is born smaller 
than man; see Dr. Duncan, 'Fecundity, Fertihty, Sterility,' 1871, p. 382. 

53 With the savage Guaranys of Paraguay, according to the accu- 
rate Azara ('Voyages dans I'Amerique merid.' tom. ii. 1809, p. 60, 179), 
the women are to the men in the proportion of 14 to 13. 



PROPORTION OF THE SEXES. 239 

excess of male over female births is less when they are illegitimate 
than when legitimate."* This has been explained by different 
writers in many different ways, as from the mothers being gener- 
ally young, from the large proportion of first pregnancies, &c. 
But we have seen that male infants, from the large size of their 
heads, suffer more than female infants during parturition; and 
as the mothers of illegitimate children must be more liable 
than other women to undergo bad labors, from various causes, 
such as attempts at concealment by tight lacing, hard work, dis- 
tress of mind, &c., their male infants would proportionally suffer. 
And this probably is the most efficient of all the causes of the 
proportion of males to females born alive being less amongst 
illegitimate children than amongst the legitimate. With most 
animals the greater size of the adult male than of the female, 
is due to the stronger males having conquered the weaker in 
their struggles for the possession of the females, and no doubt 
it is owing to this fact that the two sexes of at least some ani- 
mals differ in size at birth. Thus we have the curious fact that 
we may attribute the more frequent deaths of male than female 
infants, especially amongst the illegitimate, at least in part to 
sexual selection. 

It has often been supposed that the relative age of the two 
parents determines the sex of the offspring; and Prof. Leuckart^^ 
has advanced what he considers sufficient evidence, with respect 
to man and certain domesticated animals, that this is one im- 
portant though not the sole factor in the result. So again the 
period of impregnation relatively to the state of the female has 
been thought by some to be the efficient cause; but recent observa- 
tions discountenance this belief. According to Dr. Stockton- 
Hough,^° the season of the year, the poverty or wealth of the 
parents, residence in the country or in cities, the crossing of 
foreign immigrants, &c., all influence the proportion of the sexes. 
With mankind, polygamy has also been supposed to lead to the 
birth of a greater proportion of female infants; but Dr. J. Camp- 
belP' carefully attended to this subject in the harems of Siam, 
and concludes that the proportion of male to female births is the 
same as from monogamous unions. Hardly any animal has been 
rendered so highly polygamous as the English race-horse, and 
we shall immediately see that his male and female offspring are 
almost exactly equal in number. I will now give the facts which 
I have collected with respect to the proportional numbers of the 

^ Babbage, 'Edinburgh Journal of Science,' 1829, vol. i. p. 88; also 
p. 90, on still-born children. On illegitimate children in England, see 
'Report of Registrar-General for 1866,' p. xv. 

ss Leuckart in Wagner 'Handworterbuch der Phys.' B. iv. 1853, s. 774. 

^ Social Science Assoc, of Philadelphia, 1874. 

6"^ 'Anthropological Review,' April, 1870, p. cvili. 



240 THE DESCENT OF MAN. 

sexes of various animals; and will then briefly discuss how far 
selection has come into play in determining the result. 

Horses, — Mr. Tegetmeier has been so kind as to tabulate for me 
from the 'Racing Calendar' the births of race-horses during a 
period of twenty-one years, viz., from 1846 to 1867; 1849 being 
omitted, as no returns were that year published. The total births 
were 25,560,^^^ consisting of 12,763 males and 12,797 females, or in 
the proportion of 99.7 males to 100 females. As these numbers 
are tolerably large, and as they are drawn from all parts of 
England, during several years, we may with much confidence 
conclude that with the domestic horse, or at least with the race- 
horse, the two sexes are produced in almost equal numbers. The 
fluctuations in the proportions during successive years are closely 
like those which occur with mankind, when a small and thinly- 
populated area is considered; thus in 1856 the male horses were 
as 107.1, and in 1867 as only 92.6 to 100 females. In the tabulated 
returns the proportions vary in cycles, for the males exceeded the 
females during six successive years; and the females exceeded the 
males during two periods each of four years: this, however, may 
be accidental; at least I can detect nothing of the kind with man 
in the decennial table in the Registrar's Report for 1866. 

Dogs. — During a period of twelve years, from 1857 to 1868, the 
births of a large number of greyhounds, throughout England, 
were sent to the 'Field' newspaper; and I am again indebted to 
Mr. Tegetmeier for carefully tabulating the results. The recorded 
births were 6878, consisting of 3605 males and 3273 females, that 
is, in the proportion of 110.1 males to 100 females. The greatest 
fluctuations occurred in 1864, when the proportion was as 95.3 
males, and in 1867, as 116.3 males to 100 females. The above 
average proportion of 110.1 to 100 is probably nearly correct in 
the case of the greyhound, but whether it would hold with other 
domesticated breeds is in some degree doubtful. Mr. Cupples 
has inquired from several great breeders of dogs, and finds that 
all without exception believe that females are produced in excess; 
but he suggests that this belief may have arisen from females 
being less valued, and from the consequent disappointment pro- 
ducing a stronger impression on the mind. 

^ During eleven years a record was kept of the number of mares 
which proved barren or prematurely slipped their foals; and it de- 
serves notice, as showing how infertile these highly-nurtured and 
rather closely-interbred animals have become, that not far from one- 
third of the mares failed to produce living foals. Thus during 1866, 
809 male colts and 816 female colts were bom, and 743 mares failed to 
produce ofEspring. During 1867, 836 males and 902 females were born, 
and 794 mares failed. 



PROPORTION OF THE SEXES. 241 

Sheep. — The sexes of sheep are not ascertained by agriculturists 
until several months after birth, at the period when the males 
are castrated; so that the following returns do not give the pro- 
portions at birth. Moreover, I find that several great breeders 
in Scotland, who annually raise some thousand sheep, are firmly 
convinced that a larger proportion of males than of females die 
during the first year or two. Therefore the proportion of males 
would be somewhat larger at birth than at the age of castration. 
This is a remarkable coincidence with what, as we have seen, 
occurs with mankind, and both cases probably depend on the 
same cause. I have received returns from four gentlemen in 
England who have bred Lowland sheep, chiefly Leicesters, during 
the last ten to sixteen years; they amount altogether to 8965 
births, consisting of 4407 males and 4558 females; that is in the 
proportion of 96.7 males to 100 females. With respect to Cheviot 
and black faced sheep bred in Scotland, I have received returns 
from six breeders, two of them on a large scale, chiefly for the 
years 1867-1869, but some of the returns extend back to 1862. 
The total number recorded amounts to 50,685, consisting of 25,071 
males and 25,614 females, or in the proportion of 97.9 males to 
100 females. If we take the English and Scotch returns together, 
the total number amounts to 59,650, consisting of 29,478 males 
and 30,172 females, or as 97.7 to 100. So that with sheep at the 
age of castration the females are certainly in excess of the males, 
but probably this would not hold good at birth.^^ 

Of Cattle I have received returns from nine gentlemen of 982 
births, too few to be trusted; these consisted of 477 bull-calves 
and 505 cow-calves; i. e., in the proportion of 94.4 males to 100 
females. The Rev. "W. D. Pox informs me that in 1867 out of 34 
calves born on a farm in Derbyshire only one was a bull. Mr. 
Harrison Weir has inquired from several breeders of Pigs, and 
most of them estimate the male to the female births as about 7 
to 6. This same gentleman has bred Rabbits for many years, 
and has noticed that a far greater number of bucks are produced 
than does. But estimations are of little value. 

Of mammalia in a state of nature I have been able to learn very 
little. In regard to the common rat, I have received conflicting 
statements. Mr. R. Elliot, of Laighwood, informs me that a rat- 
catcher assured him that he had always found the males in great 

s» I am much indebted to Mr. Cupples for having- procured for me 
the above returns from Scotland as well as some of the following- 
returns on cattle. Mr. R. Elliot, of Laighwood, first called my at- 
tention to the premature deaths of the males,— a statement subse- 
quently confirmed by Mr. Aitchison and others. To this latter gen- 
tleman, and to Mr. Payan, I owe my thanks for larg-e returns as 
to sheep. 
17 



242 THE DESCENT OF MAN. 

excess, even with the young in the nest. In consequence of this, 
Mr. Elliot himself subsequently examined some hundred old ones, 
and found the statement true. Mr. F. Buckland has bred a large 
number of white rats, and he also believes that the males greatly 
exceed the females. In regard to Moles, it is said that "the males 
"are much more numerous than the females;"^'' and as the catch- 
ing of these animals is a special occupation, the statement may 
perhaps be trusted. Sir A. Smith, in describing an antelope of 
S. Africa''^ (Kobus ellipsiprymnus), remarks, that in the herds 
of this and other species, the males are few in number compared 
with the females: the natives believe that they are born in this 
proportion; others believe that the younger males are expelled 
from the herds, and Sir A. Smith says, that though he has himself 
never seen herds consisting of young males alone, others af- 
firm that this does occur. It appears probable that the young 
when expelled from the herd, would often fall a prey to the many 
beasts of prey of the country. 

BIRDS. 

With respect to the Fowl, I have received only one account, 
namely, that out of 1001 chickens of a highly-bred stock of Coch- 
ins, reared during eight years by Mr. Stretch, 487 proved males 
and 514 females; i. e., as 94.7 to 100. In regard to domestic 
pigeons there is good evidence either that the males are produced 
in excess, or that they live longer; for these birds invariably 
pair, and single males, as Mr. Tegetmeier informs me, can always 
be purchased cheaper than females. Usually the two birds reared 
from the two eggs laid in the same nest are a male and a female; 
but Mr. Harrison Weir, who has been so large a breeder, says 
that he has often bred two cocks from the same nest, and seldom 
two hens; moreover, the hen is generally the weaker of the two, 
and more liable to perish. 

With respect to birds in a state of nature, Mr. Gould and oth- 
ers*'^ are convinced that the males are generally the more numer- 
ous; and as the young males of many species resemble the fe- 
males, the latter would naturally appear to be the more numerous. 
Large numbers of pheasants are reared by Mr. Baker of Leaden- 
hall from eggs laid by wild birds, and he informs Mr. Jenner 
Weir that four or five males to one female are generally pro- 
duced. An experienced observer remarks,^ that in Scandinavia 



60 Bell, 'History of British Quadrupeds,' p. 100, 

61 'Illustrations of the Zoology of S. Africa,' 1849, pi. 29. 

62 Brehm ('Illust. Thierleben,* B. iv. s. 990) comes to the same con- 
clusion. 

63 On the authority of L. Lloyd, 'Game Birds of Sweden,' 1867, pp. 12, 
132. 



PROPORTION OF THE SEXES. 243 

the broods of the capercailzie and black-cock contain more males 
than females; and that with the Dal-ripa (a kind of ptarmigan) 
more males than females attend the leks or places of courtship; 
but this latter circumstance is accounted for by some observers 
by a greater number of hen birds being killed by vermin. From 
various facts given by White of Selborne,"^ it seems clear that the 
males of the partridge must be in considerable excess in the south 
of England; and I have been assured that this is the case in 
Scotland. Mr. Weir on Inquiring from the dealers, who receive 
at certain seasons large numbers of ruffs (Machetes pugnax), was 
told that the males are much the more numerous. This same 
naturalist has also inquired for me from the birdcatchers, who 
annually catch an astonishing number of various small species 
a/live for the London market, and he was unhesitatingly answered 
by an old and trustworthy man, that with the chaffinch the males 
are in large excess; he thought as high as 2 males to 1 female, 
or at least as high as 5 to 3.*^^ The males of the blackbird, he 
likewise maintained, were by far the more numerous, whether 
caught by traps or by netting at night. These statements may 
apparently be trusted, because this same man said that the sexes 
are about equal with the lark, the twite (Linaria montana), and 
goldfinch. On the other hand, he is certain that with the com- 
mon linnet, the females preponderate greatly, but unequally during 
different years; during some years he has found the females to 
the males as four to one. It shoald, however, be borne in mind, 
that the chief season for catching birds does not begin till Sep- 
tember, so that with some species partial migrations may have 
begun, and the flocks at this period often consist of hens alone. 
Mr. Salvin paid particular attention to the sexes of the humming- 
birds in Central America, and he is convinced that with ihost 
of the species the males are in excess; thus one year he procured 
204 specimens belonging to ten species, and these consisted of 166 
males and of only 38 females. With two other species the females 
were in excess: but the proportions apparently vary either dur- 
ing different seasons or in different localities; for on one occasion 
the males of Campylopterus hemileucurus were to the females as 
5 to 2, and on another occasion^^ in exactly the reversed ratio. As 

«4 'Nat. Hist, of Selborne,' letter xxix. edit, of 1825, vol. i. p. 139. 

^ Mr. Jenner Weir received similar information, on making in- 
quiries during the following year. To show the number of living 
chaffinches caught, I may mention that in 1869 there was a match be- 
tween two experts, and one man caught in a day 62, and another 40, 
male ahaffinches. The greatest number ever caught by one man in 
a single day was 70. 

66 'Ibis,' vol. ii. p. 260, as quoted in Gould's 'Trochilidae,' 1861, p. 52. 
For the foregoing proportions, I am indebted to Mr. Salvin for a 
table of his results. 



244 THE DESCENT OF MAN. 

bearing on this latter point, I may add, that Mr. Powys found 
in Corfu and Epirus the sexes of the chaffinch keeping apart, and 
"the females by far the most numerous;" whilst in Palestine Mr. 
Tristram found "the male flocks appearing greatly to exceed the 
"female in number."" So again with the Quiscalus major, Mr. G. - 
Taylor'^ says, that in Florida there were "very few females in 
"proportion to the males," whilst in Honduras the proportion was 
the other way, the species there having the character of a polyg- 
amist. 

FISH. 

With Fish the proportional numbers of the sexes can be ascer- 
tained only by catching them in the adult or nearly adult state; 
and there are many difficulties in arriving at any just conclu- 
sion.*'^ Infertile females might readily be mistaken for males, 
as Dr. Giinther has remarked to me in regard to trout. With some 
species the males are believed to die soon after fertilizing the 
ova. With many species the males are of much smaller size than 
the females, so that a large number of males would escape from 
the same net by which the females were caught. M. Carbonnier,'"' 
who has especially attended to the natural history of the pike 
(Esox lucius), states that many males, owing to their small size, 
are devoured by the larger females; and he believes that the 
males of almost all fish are exposed from this same cause to 
greater danger than the females. Nevertheless, in the few cases 
in which the proportional numbers have been actually observed, 
the males appear to be largely in excess. Thus Mr. R. Buist, the 
superintendent of the Stormontfield experiments, says that in 
1865 out of 70 salmon first landed for the purpose of obtaining 
the ova, upwards of 60 were males. In 1867 he again "calls atten- 
"tion to the vast disproportion of the males to the females. We 
"had at the outset at least ten males to one female." Afterwards 
females sufficient for obtaining ova were procured. He adds, 
"from the great proportion of the males, they are constantly 
"fighting and tearing each other on the spawning-beds,"^^ This 
disproportion, no doubt, can be accounted for in part, but whether 
wholly is doubtful, by the males ascending the rivers before the 
females. Mr. F. Buckland remarks in regard to trout, that "it is 



w 'Ibis,' 1860, p. 137; and 1867, p. 369. 

88 'Ibis,' 1862, p. 137. 

«9L.euckart quotes Bloch (Wagner, 'Handworterbuch der Phys.' B. 
iv. 1853, s. 775), that with fish there are twice as many males as 
females. 

''o Quoted in the 'Farmer,' March 18, 1869, p. 369. 

" 'The Stormontfield Piscicultural Experiments,' 1866, p. 23. The 
•Field' newspaper, June 29th, 1867. 



* PROPORTION OF THE SEXES. 246 

"a curious fact that the males preponderate very largely in num- 
"ber over the females. It invariably happens that when the first 
"rush of fish is made to the net, there will be at least seven or 
"eight males to one female found captive, I cannot quite account 
"for this; either the males are more numerous than the females, 
"or the latter seek safety by concealment rather than flight." He 
then adds, that by carefully searching the banks sufficient fe- 
males for obtaining ova can be found."^ Mr. H. Lee informs me 
that out of 212 trout, taken for this purpose in Lord Ports- 
mouth's park, 150 were males and 62 females. 

The males of the Cyprinidae likewise seem to be in excess; but 
several members of this Family, viz., the carp, tench, bream and 
minnow, appear regularly to follow the practice, rare in the ani- 
mal kingdom, of polyandry; for the female while spawning is 
always attended by two males, one on each side, and in the case 
of the bream by three or four males. This fact is so well known, 
that it is always recommended to stock a pond with two male 
tenches to one female, or at least with three males to two females. 
With the minnow, an excellent observer states, that on the spawn- 
ing-beds the males are ten times as numerous as the females; 
when a female comes amongst the males, "she is immediately 
"pressed closely by a male on each side; and when they have 
"been in that situation for a time, are superseded by other two 
"males. "^^ 

INSECTS. 

In this great Class, the Lepidoptera almost alone afford means 
for judging of the proportional numbers of the sexes; for they 
have been collected with special care by many good observers, 
and have been largely bred from the egg or caterpillar state. I 
had hoped that some breeders of silk-moths might have kept an 
exact record, but after writing to France and Italy, and consult- 
ing various treatises, I cannot find that this has ever been done. 
The general opinion appears to be that the sexes are nearly 
equal, but in Italy, as I hear from Professor Canestrini, many 
breeders are convinced that the females are produced in excess. 
This same naturalist, however, informs me, that in the two yearly 
broods of the Ailanthus silk-moth (Bombyx cynthia), the males 
greatly preponderate in the first, whilst in the second the two 
sexes are nearly equal, or the females rather in excess. 

In regard to Butterflies in a state of nature, several observers 

" 'Land and Water,' 1868, p. 41. 

'^Yarrell, 'Hist. British Pishes,' vol. 1. 1826, p. 307; on the Cyprinus 
carpio, p. 331; on the Tinea vulgaris, p. 331; on the Abramis brama, 
p. 336. See, for the minnow (Leuciscus phoxinus), 'Loudon's Mag. of 
Nat. Hist.' vol. v. 1832, p. 682. 
17 



246 THE DESCENT OF MAN. 

have been much struck by the apparently enormous preponder- 
ance of the males.^* Thus Mr. Bates/'^ in speaking of several spe- 
cies, about a hundred in number, which inhabit the Upper Ama- 
zons, says that the males are much more numerous that the fe- 
males, even in the proportion of a hundred to one. In North 
America, Edwards, who had great experience, estimates in the 
genus Papilio the males to the females as four to one; and Mr. 
Walsh, who informed me of this statement, says that with P. 
turnus this is certainly the case. In South Africa, Mr. R. Trimen 
found the males in excess in 19 species ;'*' and in one of these, 
which swarms in open places, he estimated the number of males 
as fifty to one female. With another species, in which the males 
are numerous in certain localities, he collected only five females 
during seven years. In the island of Bourbon, M. Maillard states 
that the males of one species of Papilio are twenty times as nu- 
merous as the females." Mr. Trimen informs me that as far as he 
has himself seen, or heard from others, it is rare for the females 
of any butterfly to exceed the males in number; but three South 
African species perhaps offer an exception. Mr. Wallace^* states 
that the females of Ornithoptera croesus, in the Malay archipelago, 
are more common and more easily caught than the males; but this 
is a rare butterfly, I may here add, that in Hyperythra, a genus of 
moths, Guenee says, that from four to five females are sent in 
collections from India for one male. 

When this subject of the proportional numbers of the sexes of 
insects was brought before the Entomological Society,^^ it was 
generally admitted that the males of most Lepidoptera, in the 
adult or imago state, are caught in greater numbers than the 
females: but this fact was attributed by various observers to the 
more retiring heabits of the females, and to the males emerging 
earlier from the cocoon. This latter circumstance is well known 
to occur with most Lepidoptera, as well as with other insects. So 
that as M. Personnat remarks, the males of the domesticated 
Bombyx Yamamai, are useless at the beginning of the season, and 
the females at the end, from the want of mates.^* I cannot, how- 
ever, persuade myself that these causes suffice to explain the 



'*Lieuckart quotes Meinecke (Wagner, 'Handworterbuch der Phys.' 
B. iv. 1853, s. 775) that the males of Butterflies are three or four times 
as numerous as the females. 

'5 'The Naturalist on the Amazons,* vol. ii. 1863, pp. 228, 347. 

'8 Four of these cases are given by Mr. Trimen in his 'Rhopalocera 
Africae Australis.' 

" Quoted by Trimen, 'Transact. Ent. Soc.,' vol. v. part iv. 1866, p. 330. 

'8 'Transact. Linn. Soc.,' vol. xxv. p. 37. 

7» 'Proc. Entomolog. Soc.,' Feb. 17th, 1868. 

80 Quoted by Dr. Wallace in 'Proc. Ent. Soc.,' 3rd series, vol. v. 1867. 
p. 487. 



PROPORTION OF THE SEXES. 247 

great exeess of males, in the above cases of certain butterflies 
which are extremely common in their native countries. Mr. Stain- 
ton, who has paid very close attention during many years to the 
smaller moths, informs me that when he collected them in the 
imago state, he thought that the males were ten times as numerous 
as the females, but that since he has reared them on a large scale 
from the caterpillar state, he is convinced that the females are 
the more numerous. Several entomologists concur in this view. 
Mr. Doubleday, however, and some others, take an opposite view, 
and are convinced that they have reared from the eggs and cater- 
pillars a larger proportion of males than of females. 

Besides the more active habits of the males, their earlier emerg- 
ence from the cocoon, and in some cases their frequenting more 
open stations, other causes may be assigned for an apparent or 
real difference in the proportional numbers of the sexes of Lepi- 
doptera, when captured in the imago state, and when reared from 
the egg or caterpillar state. I hear from Professor Canestrini, 
that it is believed by many breeders in Italy, that the female cat- 
erpillar of the silk-moth suffers more from the recent disease than 
the male; and Dr. Staudlinger informs me that in rearing Lepi- 
doptera more females die in the cocoon than males. With many 
species the female caterpillar is larger than the male, and a collect- 
or would naturally choose the finest specimens, and thus uninten- 
tionally collect a larger number of females. Three collectors have 
told me that this was their practice; but Dr. Wallace is sure that 
most collectors take all the specimens which they can find of the 
rarer kinds, which alone are worth the trouble of rearing. Birds 
when surrounded by caterpillars would probably devour the larg- 
est; and Professor Canestrini informs me that in Italy some 
breeders believe, though on insuSacient evidence, that in the first 
broods of the Ailanthus silk-moth, the wasps destroy a larger 
number of the female than of the male caterpillars. Dr. Wal- 
lace further remarks that female caterpillars, from being larger 
than the males, require more time for their development, and 
consume more food and moisture; and thus they would be ex- 
posed during a longer time to danger from ichneumons, birds, 
&c., and in times of scarcity would perish in greater numbers. 
Hence it appears quite possible that in a state of nature, fewer 
female Lepidoptera may reach maturity than males; and for 
our special object we are (concerned with their relative numbers 
at maturity, when the sexes are ready to propagate their kind. 

The manner in which the males of certain moths congregate in 
extraordinary numbers round a single female, apparently indi- 
cates a great excess of males, though this fact may perhaps be 
accounted for by the earlier emergence of the males from their 
cocoons. Mr. Stainton informs me that from twelve to twenty 
males, may often be seen congregated round a female Elachista 



248 THE DESCENT OF MAN. 

rufocinerea. It is well known that if a virgin Lasiocampa qiiercus 
or Saturnia carpini be exposed in a cage, vast nuiibers of males 
collect round her, and if confined in a room will even come down 
the chimney to her. Mr. Doubleday believes that he has seen 
from fifty to a hundred males of both these species attracted in the 
course of a single day by a female in confinement. In the Isle 
of Wight Mr. Trimen exposed a box in which a female of the 
Lasiocampa had been confined on the previous day, and five males 
soon endeavored to gain admittance. In Australia, M. Verreaux, 
having placed the female of a small Bombyx in a t30x in his pock- 
et, was followed by a crowd of males, so that about 200 entered 
the house with him.^^ 

Mr. Doubleday has called my attention to M. Staudinger's^^ list 
of Lepidoptera, which gives the prices of the males and females 
of 300 species or well-marked varieties of butterflies (Rhopalo- 
cera). The prices for both sexes of the very common species are 
of course the same; but in 114 of the rarer species they differ; 
the males being in all cases, excepting one, the cheaper. On an 
average of the prices of the 113 species, the price of the male to 
that of the female is as 100 to 149; and this apparently indicates 
that inversely the males exceed the females in the same propor- 
tion. About 2000 species or varieties of moths (Heterocera) are 
catalogued, those with wingless females being here excluded on 
account of the difference in habits between the two sexes: of 
these 2000 species, 141 differ in price according to sex, the males 
of 130 being cheaper, and those of only 11 being dearer than the 
females. The average price of the males of the 130 species, to 
that of the females, is as 100 to 143. With respect to the butter- 
flies in this priced list, Mr. Doubleday thinks (and no man in 
England has had more experience), that there is nothing in the 
habits of these species which can account for the difference in 
the prices of the two sexes, and that it can be accounted for only 
by an excess in the number of the males. But I am bound to 
add that Dr. Staudinger informs me, that he is himself of a dif- 
ferent opinion. He thinks that the less active habits of the fe- 
males and the earlier emergence of the males will account for 
his collectors securing^ a larger number of males than of females, 
and consequently for the lower prices of the former. With respect 
to specimens reared from the caterpillar-state. Dr. Staudinger 
believes, as previously stated, that a greater number of females 
than of males die whilst confined in the cocoons. He adds that 
with certain species one sex seems to preponderate over the other 
during certain years. 

Of direct observations on the sexes of Lepidoptera reared 

^ Blanchard, 'Metamorphoses, Moeurs des Insectes/ 1868, pp. 225-226. 
•» 'Lepidopteren-Doubletten Liste,' Berlin, No. x. 1866. 



PROPORTION OF THE SEXES. 249 

either from eggs or caterpillars, I have received only the few 
following cases: — 

Males. Females. 
The Rev. J. Hellins^ of Exeter reared, during 1868, 

images of 73 species, which consisted of 153 137 

Mr. Albert Jones of Eltham reared, during 1868, 

imagos of 9 species, which consisted of 159 126 

During 1869 he reared imagos from 4 species, con- 
sisting of 114 112 

Mr. Buckler of Emsworth, Hants, during 1869, 

reared imagos from 74 species, consisting of 180 169 

Dr. Wallace of Colchester reared from one brood 

of Bombyx cynthia 52 48 

Dr. Wallace raised, from cocoons of Bombyx Pern- 

yi sent from China, during 1869 224 123 

Dr. Wallace raised, during 1868 and 1869, from 

two lots of cocoons of Bombyx yama-mai 52 46 

Total 934 761 

So that in these eight lots of cocoons and eggs, males were pro- 
duced in excess. Taken together the proportion of males is as 
122.7 to 100 females. But the numbers are hardly large enough 
to be trustworthy. 

On the whole, from these various sources of evidence, all point- 
ing in the same direction, I infer that with most species of Lepi- 
doptera, the mature males generally exceed the females in num- 
ber, whatever the proportions may be at their first emergence 
from the egg. 

With reference to the other Orders of insects, I have been able 
to collect very little reliable information. With the stag-beetle 
(Lucanus cervus) "the males appear to be much more numerous 
"than the females;" but when, as Cornelius remarked during 1867, 
an unufeual number of these beetles appeared in one part of Ger- 
many, the females appeared to exceed the males as six to one. 
With one of the Elateridse, the males are said to be much more 
numerous than the females, and "two or three are often found 
"united with one female ;^^ so that here polyandry seems to pre- 
"vail." With Siagonium (StaphylinidsB), in which the males are 

83 This naturalist has been so kind as to send me some results from 
former years, in which the females seemed to preponderate; but so 
many of the figures were estimates, that I found it impossible to 
tabulate them. 

^ Gunther's 'Record of Zoological Literature,' 1867, p. 260. On the 
excess of female Lucanus, ibid. p. 250. On the males of Lucanus in 
England, Westwood, 'Modern Class, of Insects,' vol. i. p. 187. On the 
Siagonium, ibid. p. 172. 



250 THE DESCENT OF MAN. 

furnished with horDS, "the females are far more numerous than 
"the opposite sex." Mr. Janson stated at the Entomological So- 
ciety that the females of the bark-feeding Tomicus villosus are so 
common as to be a plague, whilst the males are so rare as to be 
hardly known. 

It is hardly worth while saying anything about the proportion 
of the sexes in certain species and even groups of insects, for 
the males are unknown or very rare, and the females are parthen- 
ogenetic, that is, fertile without sexual union; examples of this 
are afforded by several of the Cynipidae.^^ In all the gall-making 
CynipidaB known to Mr. Walsh, the females are four or five times 
as numerous as the males; and so it is, as he informs me, with 
the gall-making Cecidomyiiae (Diptera). With some common 
species of Saw-flies (Tenthredinae) Mr. F. Smith has reared hun- 
dreds of specimens from larvae of all sizes, but has never, reared 
a single male: on the other hand, Curtis says,^^ that with certg-in 
species (Athalia), bred by him, the males were to the females as 
six to one; whilst exactly the reverse occurred with the mature 
insects of the same species caught in the fields. In the family of 
Bees, Hermann Miiller" collected a large number of specimens of 
many species, and reared others from the cocoons, and counted 
the sexes. He found that the males of some species greatly ex- 
ceeded the females in number; in others the reverse occurred; and 
in others the two sexes were nearly equal. But as in most cases the 
males emerge from the cocoons before the females, they are at 
the commencement of the breeding season practically in excess. 
Miiller also observed that the relative number of the two sexes 
in some species differed much in different localities. But as H. 
Miiller has himself remarked to me, these remarks must be re- 
ceived with some caution, as one sex might more easily escape ob- 
servation than the other. Thus his brother Fritz Miiller has 
noticed in Brazil that the two sexes of the same species of bee 
sometimes frequent different kinds of flowers. With respect to 
the Orthoptera, I know hardly anything about the relative num- 
ber of the sexes: Korte,^^ however, says that out of 500 locusts 
which he examined, the males were to the females as five to six. 
With the Neuroptera, Mr. Walsh states that in many, but by 
no means in all the species of the Odonatous group, there is a 
great overplus of males: in the genus Hetserina, also, the males 
are generally at least four times as numerous as the females. 
In certain species in the genus Gomphus the males are equally in 

85 Walsh, in 'The American Entomologist,* vol. i. 1869, p. 103. F. 
Smith, 'Record of Zoological Literature,' 1867, p. 328. 
88 'Farm Insects,' pp. 45-46. 

87 Anwendung- der Darwinschen Lehre Verh. d. n. V. Jahrg. xxiv.' 

88 'Die Strich, Zug oder Wanderheuschrecke,' 1828, p. 20. 



PROPOKTION OF THE SEXES. 251 

excess, whilst in two other species, the females are twice or 
thrice as numerous as the males. In some European species of 
Psocus thousands of females may he collected without a single 
male, whilst with other species of the same genus both sexes are 
common.^'' In England, Mr. MacLachlan has captured hundreds 
of the female Apatania muliebris, but has never seen the male; 
and of Boreus hyemalis only four or five males have been seen 
here.^° With most of these species (excepting the Tenthredinae) 
there is at present no evidence that the females are subject to 
parthenogenesis; and thus we see how ignorant we are of the 
causes of the apparent discrepancy in the proportion of the two 
sexes. 

In the other Classes of the Articulata I have been able to collect 
still less information. With Spiders, Mr. Blackwall, who has 
carefully attended to this class during many years, writes to me 
that the males from their more erratic habits are more commonly 
seen, and therefore appear more numerous. This is actually the 
case with a few species; but he mentions several species in six 
genera, in which the females appear to be much more numerous 
than the males.^^ The small size of the males in comparison with 
the females (a peculiarity which is sometimes carried to an ex- 
treme degree), and their widely different appearance, may ac- 
count in some instances for their rarity in collections.®^ 

Some of the lower Crustaceans are able to propagate their 
kind asexually, and this will account for the extreme rarity of the 
males: thus Von Siebold®* carefully examined no less than 13,000 
specimens of Apus from twenty-one localities, and amongst these 
he found only 319 males. With some other forms (as Tanais 
and Cypris), as Fritz Miiller informs me, there is reason to be- 
lieve that the males are much shorter-lived than the females; 
and this would explain their scarcity, supposing the two sexes to 
be at first equal in number. On the other hand, Miiller has in- 
variably taken far more males than females of the Diastylidae 
and of Cypridina on the shores of Brazil; thus with a species in 
the latter genus, 63 specimens caught the same day included 57 
males; but he suggests that this preponderance may be due to 
some unknown difference in the habits of the two sexes. With 
one of the higher Brazilian crabs, namely a Gelasimus, Fritz 

*» 'Observations on N. American Neuroptera,' by H. Hagen and B. 
D. Walsh, 'Proc. Ent. Soc. Philadelphia,' Oct. 1863, pp. 168, 223, 239. 

^ 'Proc. Ent. Soc. London, Feb. 17, 1868. 

81 An other great authority with respect to this class, Prof. Thorell 
of TJpsala ('On European Spiders,' 1869-70, part t p. 205) speaks as If 
female spiders were generally commoner than the males. 

*2 See, on this subject, Mr. O. P, Cambridge, as quoted in 'Quarterly 
Journal of Science,' 1868, p. 429. 

93 'Beitrage zur Parthenogenesis,' p. 174. 



252 THE DESCENT OF MAN. 

Miiller found the males to be more numerous than the females. 
According to the large experience of Mr. C. Spence Bate, the 
reverse seems to be the case with six common British crabs, the 
names of which he has given me. 



The proportion of the sexes in relation to natv/ral selection. 

There is reason to suspect that in some cases man has by selec- 
tion indirectly influenced his own sex-producing powers. Cer- 
tain women tend to produce during their whole lives more chil- 
dren of one sex than of the other: and the same holds good of 
many animals, for instance, cows and horses; thus Mr. Wright 
of Yeldersley House informs me that one of his Arab mares, 
though put seven times to different horses, produced seven fil- 
lies. Though I have very little evidence on this head, analogy 
would lead to the belief, that the tendency to produce either 
sex would be inherited like almost every other peculiarity, for 
instance, that of producing twins; and concerning the above 
tendency a good authority, Mr. J. Downing, has communicated 
to me facts which seem to prove that this does occur in certain 
families of short-horn cattle. Col. Marshal?* has recently found 
on careful examination that the Todas, a hill-tribe of India, con- 
sist of 112 males and 84 females of all ages — that is in a ratio of 
133.3 males to 100 females. The Todas, who are polyandrous in 
their marriages, during former times invariably practiced female 
infanticide; but this practice has now been discontinued for a 
considerable period. Of the children born within late years, the 
males are more numerous than the females, in the proportion of 
124 to 100. Colonel Marshall accounts for this fact in the fol- 
lowing ingenious manner: "Let us for the purpose of illustra- 
"tion take three families as representing an average of the 
"entire tribe; say that one mother gives birth to six daughters 
"and no sons; a second mother has six sons only, whilst the 
"third mother has three sons and three daughters. The first 
"mother, following the tribal custom, destroys four daughters 
"and preserves two. The second retains her six sons. The third 
"kills two daughters and keeps one, as also her three sons. We 
"have then from the three families, nine sons and three daugh- 
"ters, with which to continue the breed. But whilst the males 
"belong to families in which the tendency to produce sons is 
"great, the females are of those of a converse inclination. Thus 
"the bias strengthens with each generation, until, as we find, 
"families grow to have habitually more sons than daughters." 

That this result would follow from the above form of infanti- 
cide seems almost certain; that is if we assume that a sex- 

94 «xhe Todas,' 1873, pp. 100, 111, 194, 196. 



PROPORTION OF THE SEXES. 253 

producing tendency is inherited. But as the above numbers are 
so extremely scanty, I have searched for additional evidence, 
but cannot decide whether what I have found is trustworthy; 
nevertheless the facts are, perhaps, worth giving. The Maories 
of New Zealand have long practiced infanticide; and Mr. Fen- 
ton®^ states that he "has met with instances of women who have 
"destroyed four, six, and even seven children, mostly females. 
"However, the universal testimony of those best qualified to 
"judge, is conclusive that this custom has for many years been 
"almost extinct. Probably the year 1835 may be named as the 
"period of its ceasing to exist." Now amongst the New Zea- 
landers, as with the Todas, male births are considerably in ex- 
cess. Mr. Fenton remarks (p. 30), "One fact is certain, although 
"the exact period of the commencement of this singular condi- 
"tion of the disproportion of the sexes cannot be demonstratively 
"fixed, it is quite clear that this course of decrease was in full 
"operation during the years 1830 to 1844, when the non-adult 
"population of 1844 was being produced, and has continued with 
"great energy up to the present time." The following statements 
are taken from Mr. Fenton (p. 26), but as the numbers are not 
large, and as the census was not accurate, uniform results cannot 
be expected. It should be borne in mind in this and the follow- 
ing cases, that the normal state of every population is an excess 
of women, at least in all civilized countries, chiefly owing to the 
greater mortality of the male sex during youth, and partly to acci- 
dents of all kinds later in life. In 1858, the native population of 
New Zealand was estimated as consisting of 31,667 males and 
24,303 females of all ages, that is in the ratio of 130.3 males to 
100 females. But during this same year, and in certain limited 
districts, the numbers were ascertained with much care, and the 
males of all ages were here 753 and the females 616; that is in 
the ratio of 122.2 males to 100 females. It is more important 
for us that during this same year of 1858, the non-adult males 
within the same district were found to be 178, and the non-adult 
females 142, that is in the ratio of 125.3 to 100. It may be added 
that in 1844, at which period female infanticide had only lately 
ceased, the non-adult males in one district were 281, and the 
non-adult females only 194, that is in the ratio of 144.8 males to 
100 females. 

In the Sandwich Islands, the males exceed the females in 
number. Infanticide was formerly practiced there to a frightful 
extent, but was by no means confined to female infants, as is 
shown by Mr. Ellis,^^ and as I have been informed by Bishop 

05 'Aboriginal Inhabitants of New Zealand; Government Report,' 
1859, p. 36. 
88 'Narrative of a Tour through Hawaii,' 1826, p. 298. 



254 THE DESCENT OF MAN. 

Staley and the Rev. Mr. Coan. Nevertheless, another apparently 
trustworthy writer, Mr. Jarves,*^ whose observations apply to 
the whole archipelago, remarks: — "Numbers of women are to 
"be found, who confess to the murder of from three to six or 
"eight children;" and he adds, "females from being considered 
"less useful than males were more often destroyed." From what 
is known to occur in other parts of the world, this statement is 
probable; but must be received with much caution. The prac- 
tice of infanticide ceased about the year 1819, when idolatry was 
abolished and missionaries settled in the Islands. A careful cen- 
sus in 1839 of the adult and taxable men and women in the island 
of Kauai and in one district of Oahu (Jarves, p. 404), gives 4723 
males and 3776 females; that is in the ratio of 125.08 to 100. At 
the same time the number of males under fourteen years in Kauai 
and under eighteen in Oahu was 1797, and of females of the same 
ages 1429; and here we have the ratio of 125.75 males to 100 
females. 

In a census of all the islands in 1850,®^ the males of all ages 
amount to 86,272, and the females to 33,128, or as 109.49 to 100. 
The males under seventeen years amounted to 10,773, and the 
females under the same age to 9593, or as 112.3 to 100. From the 
census of 1872, the proportion of males of all ages (including 
half-castes) to females, is as 125.36 to 100. It must be borne in 
mind that all these returns for the Sandwich Islands give the 
proportion of living males to living females, and not of the births; 
and judging from all civilized countries the proportion of males 
would have been considerably higher if the numbers had referred 
to births.^ 

; 87 'History of the Sandwich Islands,' 1843, p, 93. 

»8 This is given in the Rev. H. T. Cheever's 'Life in tlie Sandwich 
Islands,' 1851, p. 277. 

»» Dr. Coulter, in describing ('Journal R. Geograph. Soe,' vol. v. 
1835, p. 67) the state of California about the year 1830, says that the 
natives, reclaimed by the Spanish missionaries, have nearly all per- 
ished, or are perishing, although well treated, not driven from their 
native land, and kept from the use of spirits. He attributes this, in 
great part, to the undoubted fact that the men greatly exceed the 
wom.en in number; but he does not know whether this is due to a 
failure of female offspring, or to more females dying during early 
youth. The latter alternative, according to all analogy, is very im- 
probable. He adds that "infanticide, properly so called, is not com- 
"mon, though very frequent recourse is had to abortion." If Dr. 
Coulter is correct about infanticide, this case cannot be advanced in 
support of Col. Marshall's view. From the rapid decrease of the re- 
claimed natives, we may suspect that, as in the cases lately given, 
their fertility has been diminished from changed habits of life. 

I had hoped to gain some light on this subject from the breeding of 
do&s; inasmuch as in most breeds, with the exception, perhaps, of 



PROPOKTION OF THE SEXES. 255 

From the several foregoing cases we have some reason to 
believe that infanticide practiced in the manner above explained, 
tends to make a male-producing race; but I am far from sup- 
posing that this practice in the case of man, or some analogous 
process with other species, has been the sole determining cause 
of an excess of males. There may be some unknown law leading 
to this result in decreasing races, which have already become 
somewhat infertile. Besides the several causes previously al- 
luded to, the greater facility of parturition amongst savages, 
and the less consequent injury to their male infants, would 
tend to increase the proportion of live-born males to females. 
There does not, however, seem to be any necessary connection 
between savage life and a marked excess of males; that is if we 
may judge by the character of the scanty offspring of the lately 
existing Tasmanians and of the crossed offspring of the Tahi- 
tians now inhabiting Norfolk Island. 

As the males and females of many animals differ somewhat in 
habits and are exposed in different degrees to danger, it is 
probable that in many cases, more of one sex than of the other 
are habitually destroyed. But as far as I can trace out the com- 
plication of causes, an indiscriminate though large destruction 
of either sex would not tend to modify the sex-producing power 
of the species. With strictly social animals, such as bees or ants, 
which produce a vast number of sterile and fertile females in 
comparison with the males, and to whom this preponderance is 
of paramount importance, we can see that those communities 
would flourish best which contained females having a strong 
inherited tendency to produce more and more females; and in 
such cases an unequal sex-producing tendency would be ulti- 
mately gained through natural selection. With animals living 
in herds or troops, in which the males come to the front and 
defend the herd, as with the bisons of North America and certain 

greyhounds, many more female puppies are destroyed than males, 
just as with the Toda infants. Mr. Cupples assures me that this is 
usual with Scotch deer-hounds. Unfortunately, I know nothing of 
the proportion of the sexes in any breed, excepting greyhounds, and 
there the male births are to the female as 110.1 to 100. Now from in- 
quiries made from many breeders, it seems that the females are in 
some respects more esteemed, though otherwise troublesome; and it 
does not appear that the female puppies of the best-bred dogs are 
systematically destroyed more than the males, though this does some- 
times take place to a limited extent. Therefore I am unable to de- 
cide whether we can, on the above principles, account for the pre- 
ponderance of male births in greyhounds. On the other hand, we 
have seen that with horses, cattle, and sheep, which are too valuable 
for the young of either sex to be destroyed, if there is any difference, 
the females are slightly in excess. 



256 THE DESCENT OF MAN. 

baboons, it is conceivable that a male-producing tendency might 
be gained by natural selection; for the individuals of the better 
defended herds would leave more numerous descendants. In 
the case of mankind the advantage arising from having a pre- 
ponderance of men in the tribe is supposed to be one chief cause 
of the practice of female infanticide. 

In no case, as far as we can see, would an inherited tendency 
to produce both sexes in equal numbers or to produce one sex 
in excess, be a direct advantage or disadvantage to certain in- 
dividuals more than to others; for instance, an individual with 
a tendency to produce more males than females would not succeed 
better in the battle for life than an individual with an opposite 
tendency; and therefore a tendency of this kind could not be 
gained through natural selection. Nevertheless, there are certain 
animals (for instance, fishes and cirripedes) in which two or more 
males appear to be necessary for the fertilization of the female; 
and the males accordingly largely preponderate, but it is by no 
means obvious that this male-producing tendency could have been 
acquired. I formerly thought that when a tendency to produce 
the two sexes in equal numbers was advantageous to the species, 
it would follow from natural selection, but I now see that the 
whole problem is so intricate that it is safer to leave its solution 
for the future. 



SEXUAL SELECTION. 257 



CHAPTER IX. 

SECONDARY SEXUAL CHARACTERS IN THE LOWER 
CLASSES OF THE ANIMAL KINGDOM. 

These characters absent in the lower classes— Brilliant colors— Mol- 
lusca— Annelids — Crustacea, secondary sexual characters strongly 
developed; dimorphism; color; characters not acquired before 
maturity— Spiders, sexual colors of; stridulation by the males— 
Myrlapoda. 

With animals belonging to the lower classes, the two sexes 
are not rarely united in the same individual, and therefore sec- 
ondary sexual characters cannot be developed. In many cases 
where the sexes are separate, both are permanently attached 
to some support, and the one cannot search or struggle for the 
other. Moreover it is almost certain that these animals have too 
imperfect senses and much too low mental powers, to appreciate 
each other's beauty or other attractions, or to feel rivalry. 

Hence in these clases or sub-kingdoms, such as the Protozoa, 
Coelenterata, Echinodermata, Scolecida, secondary sexual charac- 
ters, of the kind which we have to consider, do not occur; and 
this fact agrees with the belief that such characters in the higher 
classes have been acquired through sexual selection, which de- 
pends on the will, desire, and choice of either sex. Nevertheless 
some few apparent exceptions occur; thus, as I hear from Dr. 
Baird, the males of certain Entozoa, or internal parasitic worms, 
differ slightly in color from the females; but we have no reason 
to suppose that such differences have been augmented through 
sexual selection. Contrivances by which the male holds the fe- 
male, and which are indispensable for the propagation of the 
species, are independent of sexual selection, and have been ac- 
quired through ordinary selection. 

Many of the lower animals, whether hermaphrodites or with 
separate sexes, are ornamented with the most brilliant tints, or 
are shaded and striped in an elegant manner; for instance, many 
corals and sea-anemones (Actinise), some jelly-fish (Medusae, 
Porpita, &c.), some Planariae, many star-fishes, Echini, Ascidians, 
&c.; but we may conclude from the reasons already indicated, 
18 



258 THE DESCENT OF MAN. 

namely the union of the two sexes in some of these animals, the 
permanently affixed condition of others, and the low mental 
powers of all, that such colors do not serve as a sexual attraction, 
and have not been acquired through sexual selection. It should 
be borne in mind that in no case have we sufficient evidence that 
colors have been thus acquired, except where one sex is much 
more brilliantly or conspicuously colored than the other, and 
where there is no difference in habits between the sexes sufficient 
to account for their different colors. But the evidence is rendered 
as complete as it can ever be, only when the more ornamented 
individuals, almost always the males, voluntarily display their 
attractions before the other sex; for we cannot believe that such 
display is useless, and if it be advantageous, sexual selection 
will almost inevitably follow. We may, however, extend this 
conclusion to both sexes, when colored alike, if their colors are 
plainly analogous to those of one sex alone in certain other 
species of the same group. 

How, then, are we to account for the beautiful or even gor- 
geous colors of many animals in the lowest classes? It appears 
doubtful whether such colors often serve as a protection; but 
that we may easily err on this head, will be admitted by every 
one who reads Mr. Wallace's excellent essay on this subject. It 
would not, for instance, at first occur to any one that the trans- 
parency of the Medusae, or jelly-fishes, is of the highest service 
to them as a protection; but when we are reminded by Hackel 
that not only the medusse, but many floating mollusca, crusta- 
ceans, and even small oceanic fishes partake of this same glass- 
like appearance, often accompanied by prismatic colors, we can 
hardly doubt that they thus escape the notice of pelagic birds 
and other enemies. M. Giard is also convinced^ that the bright 
tints of certain sponges and ascidians serve as a protection. Con- 
spicuous colors are likewise beneficial to many animals as a 
warning to their would-be devourers that they are distasteful, or 
that they possess some special means of defense; but this subject 
will be discussed more conveniently hereafter. 

We can, in our ignorance of most of the lowest animals, only 
say that their bright tints result either from the chemical na- 
ture or the minute structure of their tissues, independently of any 
benefit thus derived. Hardly any color is finer than that of ar- 
terial blood; but there is no reason to suppose that the color of 
the blood is in itself any advantage; and though it adds to the 
beauty of the maiden's cheek, no one will pretend that it has been 
acquired for this purpose. So again with many animals, espe- 
cially the lower ones, the bile is richly colored; thus, as I am in- 
formed by Mr. Hancock, the extreme beauty of the Eolidse (naked 

1 'Archives de Zoolog-. Exper.,' Oct. 1872, p. 563. 



MOLLUSCS. 259 

sea-slugs) is chiefly due to the biliary glands being seen through 
the translucent integuments — this beauty being probably of no 
service to these animals. The tints of the decaying leaves in an 
American forest are described by every one as gorgeous; yet no 
one supposes that these tints are of the least advantage to the 
trees. Bearing in mind how many substances closely analogous 
to natural organic compounds have been recently formed by chem- 
ists, and which exhibit the most splendid colors, it would have 
been a strange fact if substances similarly colored had not often 
originated, independently of any useful end thus gained, in the 
complex laboratory of living organisms. 

The sub-kingdom of the Mollusca. — Throughout this great divis- 
ion of the animal kingdom, as far as I can discover, secondary 
sexual characters, such as we are here considering, never occur. 
Nor could they be expected in the three lowest classes, namely in 
the Ascidians, Polyzoa, and Brachiopods (constituting the Mollus- 
coida of some authors), for most of these animals are permanently 
affixed to a support or have their sexes united in the same Individ' 
ual. In the Lamellibranchiata, or bivalve shells, hermaphrodit- 
ism is not rare. In the next higher class of the Gasteropoda, or 
univalve shells, the sexes are either united or separate. But in 
the latter case the males never possess special organs for find- 
ing, securing, or charming the females, or for fighting with other 
males. As I am informed by Mr. Gwyn Jeffreys, the sole external 
difference between the sexes consists in the shell sometimes dif- 
fering a little in form; for instance, the shell of the male peri- 
winkle (Littorina littorea) is narrower and has a more elongated 
spire than that of the female. But differences of this nature, it 
may be presumed, are directly connected with the act of reproduc- 
tion, or with the development of the ova. 

The Gasteropoda, though capable of locomotion and furnished 
with imperfect eyes, do not appear to be endowed with sufficient 
mental powers for the members of the same sex to struggle to- 
gether in rivalry, and thus to acquire secondary sexual characters. 
Nevertheless with the pulmoniferous gasteropods, or land-snails, 
the pairing is preceded by courtship; for these animals, though 
hermaphrodites, are compelled by their structure to pair together. 
Agassiz remarks,- "Quiconque a eu I'occasion d'observer les amours 
"des limagons, ne saurait mettre en doute le seduction deployee 
"dans les mouvements et les allures qui pr6parent et accomplis- 
"sent le double embrassement de ces hermaphrodites." These 
animals appear also susceptible of some degree of permanent 
attachment: an accurate obser/er, Mr. Lonsdale, informs me 
that he placed a pair of land-snails (Helix pomatia), one of which 

2 'D© I'Espece et de la Class. &c., 1869, p. 106. 



260 THE DESCENT OF MAN. 

was weakly, into a small and ill-provided garden. After a short 
time the strong and healthy individual disappeared, and was 
traced by its track of slime over a wall into an adjoining well- 
stocked garden. Mr. Lonsdale concluded that it had deserted its 
sickly mate; but after an absence of twenty-four hours it re- 
turned, and apparently communicated the result of its successful 
exploration, for both then started along the same track and dis- 
appeared over the wall. 

Even in the highest class of the Mollusca, the Cephalopoda or 
cuttlefishes, in which the sexes are separate, secondary sexual 
characters of the present kind do not, as far as I can discover, 
occur. This is a surprising circumstance, as these animals pos- 
sess highly-developed sense-organs and have considerable mental 
powers, as will be admitted by every one who has watched their 
artful endeavors to escape from an enemy.^ Certain Cephalopoda, 
however, are characterized by one extraordinary sexual character, 
namely, that the male element collects within one of the arms 
or tentacles, which is then cast off, and clinging by its sucking- 
discs to the female, lives for a time an independent life. So com- 
pletely does the cast-off arm resemble a separate animal, that it 
was described by Cuvier as a parasitic worm under the name of 
Hectocotyle. But this marvelous structure may be classed as a 
primary rather than as a secondary sexual character. 

Although with the Mollusca sexual selection does not seem to 
have come into play; yet many univalve and bivalve shells, such 
as volutes, cones, scallops, &c., are beautifully colored and shaped. 
The colors do not appear in most cases to be of any use as a 
protection; they are probably the direct result, as in the lowest 
classes, of the nature of the tissues; the patterns and the sculp- 
ture of the shell depending on its manner of growth. The amount 
of light seems to be influential to a certain extent; for although, 
as repeatedly stated by Mr. Gwyn Jeffreys, the shells of some spe- 
cies living at a profound depth are brightly colored, yet we gen- 
erally see the lower surfaces, as well as the parts covered by 
the mantle, less highly-colo-'ed than the upper and exposed sur- 
faces.* In some cases, as with shells living amongst corals or 
brightly-tinted sea- weeds, the bright colors may serve as a pro- 
tection.^ But that many of the nudi-branch mollusca, or sea.-slugs, 

3 See, for instance, the account which I have given in my 'Journal 
of Researches,' 1845, p. 7. 

* I have given ('Geolog. Observations on Volcanic Islands,' 1844, p. 53) 
a curious instance of the influence of light on the colors of a frondes- 
cent incrustation, deposited by the surf on the coast-rocks of Ascen- 
sion, and formed by the solution of triturated sea-shells. 

^ Dr. Morse has lately discussed this subject in his paper on the 
Adaptive Coloration of Mollusca, 'Proc. Boston See. of Nat. Hist.,' 
vol. xiv., April, 1871. 



MOLLUSCS. 261 

are as beautifully colored as any shells, may be seen in Messrs. 
Alder and Hancock's magnificent work; and 'from information 
kindly given me by Mr. Hancock, it seems extremely doubtful 
whether these colors usually serve as a protection. With some 
species this may be the case, as with one kind which lives on the 
green leaves of algae, and is itself bright-green. But many bright- 
ly-colored, white or otherwise conspicuous species, do not seek 
concealment; whilst again some equally conspicuous species, as 
well as other dull-colored kinds, live under stones and in dark 
recesses. So that with these nudi-branch molluscs, color appar- 
ently does not stand in any close relation to the nature of the 
places which they inhabit. 

These naked sea-slugs are hermaphrodites, yet they pair to- 
gether, as do land-snails, many of which have extremely pretty 
shells. It is conceivable that two hermaphrodites, attracted by 
each other's greater beauty, might unite and leave offspring which 
would inherit their parents' greater beauty. But with such lowly- 
organized creatures this is extremely improbable. Nor is it at all 
obvious how the offspring from the more beautiful pairs of her- 
maphrodites would have any advantage over the offspring of the 
less beautiful, so as to increase in number, unle-ss indeed vigor 
and beauty generally coincided. V/e have not here the case of a 
number of males becoming mature before the females, with the 
more beautiful males selected by the more vigorous females. If, 
indeed, brilliant colors were beneficial to a hermaphrodite ani- 
mal in relation to its general habits of life, the more brightly- 
tinted individuals would succeed best and would increase in 
number; but this would be a case of natural and not of sexual 
selection. 

Sub-Mngdom of the Vermes: Class, Annelida (or Sea-worms). 
— In this class, although the sexes, when separate, sometimes dif- 
fer from each other in characters of such importance that they 
have been placed under distinct genera or even families, yet the 
differences do not seem of the kind which can be safely at- 
tributed to sexual selection. These animals are often beautifully 
colored, but as the sexes do not differ in this respect, we are but 
little concerned with them. Even the Nemertians, though so 
lowly organized, "vie in beauty and variety of coloring with any 
"other group in the invertebrate series;" yet Dr. Mcintosh^ can- 
not discover that these colors are of any service. The sedentary 
annelids become duller-colored, according to M. Quatrefages,' 
after the period of reproduction; and this I presume may be at- 

« See his beautiful monograph on 'British Annelids, part i. 1873, p. 3. 
' See M. Perrier, 'I'Origine de I'Homme d'apres Darwin,' 'Revue 
Scientifique,' Feb. 1873, p. 866. 
13 



262 THE DESCENT OF MAN. 

tributed to tlieir less vigorous condition at that time. All these 
worm-like animals apparently stand too low in the scale for the 
individuals of either sex to exert any choice in selecting a part- 
ner, or for the individuals of the same sex to struggle together 
in rivalry. 

Sitb-Mngdom of the Arthropoda: Class, Crustacea. — In this 
great class we first meet with undoubted secondary sexual char- 
acters, often developed in a remarkable manner. Unfortunately 
the habits of crustaceans are very imperfectly known, and we 
cannot explain the uses of many structures peculiar to one sex. 
With the lower parasitic species the males are of small size, and 
they alone are furnished with perfect swimming-legs, antennae 
and sense-organs; the females being destitute of these organs, 
with their bodies often consisting of a mere distorted mass. But 
these extraordinary differences between the two sexes are no 
doubt related to their widely different habits of life, and con- 
sequently do not concern us. In various crustaceans, belonging 
to distinct families, the anterior antennae are furnished with pe- 
culiar thread-like bodies, which are believed to act as smelling- 
organs, and these are much more numerous in the males than in 
the females. As the males, without any unusual development of 
their olfactory organs, would almost certainly be able sooner or 
later to find the females, the increased number of the smelling- 
threads has probably been acquired through sexual selection, by 
the better provided males having been the more successful in 
finding partners and in producing offspring. Fritz Miiller has 
described a remarkable dimorphic species of Tanais, in which the 
male is represented by two distinct forms, which never graduate 
into each other. In the one form the male is furnished with 
more numerous smelling-threads, and in the other form with 
more powerful and more elongated chelae or pincers, which serve 
to hold the female. Fritz Miiller suggests that these differences 
between the two male forms of the same species may have origi- 
nated in certain individuals having varied in the number of the 
smelling-threads, whilst other individuals varied in the shape 
and size of their chelae; so that of the former, those which were 
best able to find the female, and of the latter, those which were 
best able to hold her, have left the greatest number of progeny 
to inherit their respective advantages.^ 

In some of the lower crustaceans, the right anterior antenna 
of the male differs greatly in structure from the left, the latter 

8 'Facts and Arguments for Darwin,' English translat. 1869, p. 20. 
See the previous discussion on the olfactory threads. Sars has de- 
scribed a somewhat analogous case (as quoted in 'Nature,' 1870, p. 455) 
in a Norwegian crustacean, the Pontoporeia affinis. 



CRUSTACEANS. 



263 



resembling in its simple tapering joints the antennae of the fe- 
male. In the male the modified antenna is either swollen in the 
^ middle or angularly bent, or converted 

(fig. 4.) into an elegant, and sometimes 
wonderfully complex, prehensile organ.' 
It serves, as I hear from Sir J. Lubbock, 
to hold the female, and for this same pur- 
pose one of the two posterior legs (b) on 
the same side of the body is converted 
into a forceps. In another family the 
inferior or posterior antennae are "curi- 
ously zigzagged'* in the males alone. 

In the higher crustaceans the anterior 
legs are developed into chelae or pincers; 
and these are generally larger in the male 
than in the female, — so much so that the 
market value of the male edible crab (Can- 
cer pagurus), according to Mr. C. Spence 
Bate, is five times as great as that of the 
female. In many species the chelae are of 
unequal size on the opposite side of the 
body, the right-hand one being, as I am 
informed by Mr. Bate, generally, though 
not invariably, the largest. This inequal- 
ity is also often much greater in the male 
than in the female. The two chelae of the 
male often differ in structure (figs. 5, 6, 
and 7), the smaller one resembling that of 
the female. V/hat advantage is gained by 
their inequality in size on the opposite 
sides of the body, and by the inequality 
being much greater in the male than in 
the female; and why, when they are of 
equal size, both are often much larger in the male than in the 
female, is not known. As I hear from Mr. Bate, the 
chelae are sometimes of such length and size that they 
cannot possibly be used for carrying food to the mouth. 
In the males of certain fresh-water prawns (Palaemon) the right 
leg is actually longer than the whole body.^° The great size of 
the one leg with its chel® may aid the male in fighting with his 




Fig-. 4. Labidocera Dar- 
winii (from Lubbock). 

a. Part of right anterior 
antenna of male, form- 
ing a prehensile organ. 

b. Posterior pair of thor- 
acic leg's of male. 

c. Ditto of female. 



» See Sir J. Lubbock in 'Annals and Mag. of Nat. Hist.,' vol. xi. 
1853, pi. i. and x. ; and vol. xii. (1853) pi, vii. See, also, Lubbock in 
'Transact. Ent. Soc.,' vol. iv. new series, 1856-1858, p. 8. With respect 
to the zig-zagged antennae mentioned below, see Fritz Muller, 'Facts 
and Arguments for Darwin,' 1869, p. 40, foot-note. 

"> See a paper by Mr. C. Spence Bate, with figures, in 'Proc. Zoolog. 



264 



THE DESCENT OF MAN. 



rivals; but this will not account for their inequality in the fe- 
male on the opposite sides of the body. In Gelasimus, according 




Fl*'. 5. Anterior part of body of Callianassa (from Milne-Edwards), 

showing the unequal and differently constructed right 

and left-hand chelae of the male. 

N. B.— The artist by mistake has reversed the drawing, and made 
the left-hand chela the largest. 





Fig. 6. 



Fig. 7. 



Fig. 6. Second leg of male OrchestiaTucuratinga (from Fritz Muller^ 
Fig. 7. Ditto of female. 

to a statement quoted by Milne-Edwards," the male and the fe- 
male live in the same burrow, and this shows that they pair; 
the male closes the mouth of the burrow with one of its chel^, 
which is enormously developed; so that here it indirectly serves 
as a means of defense. Their main use however, is probably to 



Soc.,' 1868, p. 363; and on the nomenclature of the genus, ibid. p. 585. 
I am greatly indebted to Mr. Spence Bate for nearly all the above 
statements with respect to the chelae of the higher crustaceans. 
" 'Hist. Nat. des Crust.' torn. ii. 1837, p. 50. 



CRUSTACEANS. 265 

seize and to secure the female, and this in some instances, as 
with G-ammarus, is known to be the case. The male of the her- 
mit or soldier crab (Pagurus) for weeks together, carries about 
the shell inhabited by the female.^- The sexes, however, of the 
common shore-crab (Carcinus manas), as Mr. Bate informs me, 
unite directly after the female has moulted her hard shell, when 
she is so soft that she would be injured if seized by the strong 
pincers of the male; but as she is caught and carried about by 
the male before moulting, she could then be seized with impunity. 

Fritz Miiller states that certain species of Melita are distin- 
guished from all other amphipods by the females having "the 
"coxal lamellae of the penultimate pair of feet produced into 
"hook-like processes, of which the males lay hold with the hands 
"of the first pair." The development of these hook-like proc- 
esses has probably followed from those females which were the 
most securely held during the act of reproduction, having left 
the largest number of offspring. Another Brazilian amphipod 
(Orchestia Darwinii, fig. 8) presents a case of dimorphism, like 
that of Tanais; for there are two male forms, which differ in the 
structure of their chelae.^^ As either chela would certainly suf- 
fice to hold the female, — for both are now used for this purpose, 
— the two male forms probably originated by some having va- 
ried in one manner and some in another; both forms having 
derived certain special, but nearly equal advalitages, from their 
differently shaped organs. 

It is not known that male crustaceans fight together for the 
possession of the females, but it is probably the case, for with 
most animals when the male is larger than the female, he seems 
to owe his greater size to his ancestors having fought with other 
males during many generations. In most of the orders, espe- 
cially in the highest or the Brachyura, the male is larger than the 
female; the parasitic genera, however, in which the sexes follov/ 
different habits of life, and most of the Entomostraca must be 
excepted. The chelae of many crustaceans are weapons well 
adapted for fighting. Thus when a Devil-crab (Portunus puber) 
was seen by a son of Mr. Bate fighting with a Carcinus maenas, 
the latter was soon thrown on its back, and had every limb torn 
from its body. When several males of a Brazilian Gelasimus, a 
species furnished with immense pincers, were placed together in 
a glass vessel by Fritz Miiller, they mutilated and killed one 
another. Mr. Bate put a large male Carcinus masnas into a pan 
of water, inhabited by a female which was paired with a smaller 
male; but the latter was soon dispossessed. Mr. Bate adds, "if 



" Mr. C. Spence Bate, 'Brit. Assoc, Fourth Report on the Fauna of 
B. Devon.' 
13 Fritz Muller, 'Facts and Arguments for Darwin,' 1869, pp. 25-28. 



266 



THE DESCENT OF MAN. 



*'lfiey fought, the victory was a bloodless one, for I saw no 
"wounds." This same naturalist separated a male sand-skipper 
(so common on our sea-shores), Gammarus marinus, from its 
female, both of whom were imprisoned in the same vessel with 
many individuals of the same species. The female, when thus 




Fig. 8. Orchestia Darwinii (from Fritz Muller), showing the differ- 
ently-constructed chelae of the two male forms. 

divorced, soon joined the others. After a time the male was put 
again into the same vessel; and he then, after swimming about 
for a time, dashed into the crowd, and without any fighting at 
once took away his wife. This fact shows that in the Amphi- 
poda, an order low in the scale, the males and females recognize 
each other, and are mutually attached. 



CRUSTACEANS. 267 

The mental powers of the Crustacea are probably higher than 
at first sight appears probable. Any one who tries to catch one 
of the shore-crabs, so common on tropical coasts, will perceive 
how wary and alert they are. There is a large crab (Birgus 
latro), found on coral islands, which makes a thick bed of the 
picked fibres of the cocoa-nut, at the bottom of a deep burrow. 
It feeds on the fallen fruit of this tree by tearing off the husk, 
fibre by fibre; and it always begins at that end where the three 
eye-like depressions are situated. It then breaks through one of 
these eyes by hammering with its heavy front pincers, and turn- 
ing round, extracts the albuminous core with its narrow posterior 
pincers. But these actions are probably instinctive, so that 
they would be performed as well by a young animal as by an old 
one. The following case, however, can hardly be so considered: 
a trustworthy naturalist, Mr. Gardner,^* whilst watching a shore- 
crab (Gelasimus) making its burrow, threw some shells towards 
the hole. One rolled in, and three other shells remained within 
a few inches of the mouth. In about five minutes the crab 
brought out the shell which had fallen in, and carried it away to 
the distance of a foot; it then saw the three other shells lying 
near, and evidently thinking that they might likewise roll in, 
carried them to the spot where it had laid the first. It would, I 
think, be difficult to distinguish this act from one performed by 
man by the aid of reason. 

Mr. Bate does not know of any well-marked case of difference 
of color in the two sexes of our British crustaceans, in which 
respect the sexes of the higher animials so often differ. In some 
cases, however, the males and females differ slightly in tint, but 
Mr. Bate thinks not more than may be accounted for by their 
different habits of life, such as by the male wandering more 
about, and being thus more exposed to the light. Dr. Power 
tried to distinguish by color the sexes of the several species which 
inhabit the Mauritius, but failed, except with one species of 
Squilla, probably S. stylifera, the male of which is described as 
being "of a beautiful bluish-green," v/ith some of the appen- 
dages cherry-red, whilst the female is clouded v/ith brown and 
gray, "with the red about her much less vivid than in the male."^^ 
In this case, we may suspect the agency of sexual selection. 
From M. Bert's observations on Daphnia, when placed in a vessel 
illuminated by a prism, we have reason to believe that even the 
lowest crustaceans can distinguish colors. With Saphirina (an 
oceanic genus of Bntomostraca), the males are furnished with 

1* 'Travels in the Interior of Brazil,' 1846, p. HI. I have given, in 
my 'Journal of Researches,' p. 463, an account of the habits of the 
Birgus. 

15 Mr. Ch. Fraser, in 'Proc Zoolog. Soc.,' 1869, p. 3. I am indebted 
to Mr. Bate for Dr. Power's statement. 



268 THE DESCENT OF MAN. 

miuute shields or cell-like bodies, which exhibit beautiful chang- 
ing colors; these are absent in the females, and in both sexes of 
one species.^® It would, liowever, be extremely rash to conclude 
that these curious organs serve to attract the females. I am in- 
formed by Fritz Miiller, that in the female of a Brazilian species 
of Gelasimus, the whole body is of a nearly uniform grayish- 
brown. In the male the posterior part of the cephalo-thorax 
is pure white, with the anterior part of a rich green, shading 
into dark brown; and it is remarkable that these colors are liable 
to change in the course of a few minutes — the white becoming 
dirty gray or even black, the green "losing much of its brilliancy." 
It deserves especial notice that the males do not acquire their 
bright colors until they become mature. They appear to be 
much more numerous than 'the females; they differ also in the 
larger size of their chelae. In some species of the genus, prob- 
ably in all, the sexes pair and inhabit the same burrow. They 
are also, as we have seen, highly intelligent animals. From 
these various considerations it seems probable that the male in 
this species has become gaily ornamented in order to attract or 
excite the female. 

It has just been stated that the male Gelasimus does not ac- 
quire his conspicuous colors until mature and nearly ready to 
breed. This seems a general rule in the whole class in respect to 
the many remarkable structural differences between the sexes. 
We shall hereafter find the same law prevailing throughout the 
great sub-kingdom of the Vertebrata; and in all cases it is emi- 
nently distinctive of characters which have been acquired through 
sexual selection. Fritz Miiller" gives some striking instances of 
this law; thus the male sand-hopper (Orchestia) does not, until 
nearly full grown, acquire his large claspers, which are very dif- 
ferently constructed from those of the female; whilst young, his 
claspers resemble those of the female. 

Class, Arachnida (Spiders). — The sexes do not generally differ 
much in color, but the males are often darker than the females, 
as may be seen in Mr. Blackwall's magnificent work.^^ In some 
species, however, the difference is conspicuous: thus the female 
of Sparassus smaragdulus is dullish green, whilst the adult male 
has the abdomen of a fine yellow, with three longitudinal stripes 
of rich red. In certain species of Thomisus the sexes closely re- 
semble each other, in others they differ much; and analogous 
cases occur in many other genera. It is often difficult to say 
which of the two sexes departs most from the ordinary coloration 

^« Claus, 'Die freilebenden Copepoden,' 1863, s. 35. 
" 'Facts and Arguments,' &c., p. 79. 

18 'A History of the Spiders of Great Britain,' 1861-64. For the fol- 
lowing facts, see pp. 77, 88, 102. 



SPIDERS. 269 

of the genus to whicli the species belong; but Mr. Blackwall 
thinks that, as a general rule, it is the male; and Canestrini^^ re- 
marks that in certain genera the males can be specifically dis- 
tinguished with ease, but the females with great difficulty. I am 
informed by Mr. Blackwall that the sexes whilst young usually 
resemble each other; and both often undergo great changes in 
color during their successive moults, before arriving at maturity. 
In other cases the male alone appears to change color. Thus 
the male of the above bright-colored Sparassus at first resembles 
the female, and acquires his peculiar tints only when nearly 
adult. Spiders are possessed of acute senses, and exhibit much 
intelligence; as is well known, the females often show the strong- 
est affection for their eggs, which they carry about enveloped 
in a silken web. The males search eagerly for the females, and 
have been seen by Canestrini and others to fight for possession of 
them. This same author says that the union of the two sexes 
has been observed in about twenty species; and he asserts posi- 
tively that the female rejects some of the males who court her, 
threatens them with open mandibles, and at last after long hesi- 
tation accepts the chosen one. From these several considera- 
tions, we may admit with some confidence that the well-marked 
differences in color between the sexes of certain species are the 
results of sexual selection; though we have not here the best 
kind of evidence, — the display by the male of his ornaments. 
From the extreme variability of color in the male of some species, 
for instance of Theridion lineatum, it would appear that these 
sexual characters of the males have not as yet become well fixed. 
Canestrini draws the same conclusion from the fact that the 
males of certain species present two forms, differing from each 
other in the size and length of their jaws; and this reminds us 
of the above cases of dimorphic crustaceans. 

The male is generally much smaller than the female, some- 
times to an extraordinary degree,=='' and he is forced to be ex- 
tremely cautious in making his advances, as the female often 
carries her coyness to a dangerous pitch. De Geer saw a male 
that "in the midst of his preparatory caresses was seized by the 
"object of his attentions, enveloped by her in a web and then 6.e- 

i« This author has recently published a valuable essay on the 'Car- 
atteri sessuali secondarii degli Arachnidi,' in the 'Atti della Soc. 
Veneto-Trentina di So. Nat. Padova, vol. i. Fasc. 3, 1873. 

20 Aug-. Vinson ('Araneides des lies de la Reunion,' pi. vi. fig-s. 1 and 
2) gives a g-ood instance of the small size of the male, in Epeira nigra. 
In this species, as I may add, the male is testaceous and the female 
black with leg's banded v/ith red. Other even more striking cases of 
inequality in size between the sexes have been recorded ('Quarterly 
Journal of Science,* 1868, July, p. 429); but I have not seen the origi- 
nal accounts. 



270 THE DESCENT OF MAN. 

"voured, a sight which, as he adds, filled him with horror and 
indignation.""' The Rev. O. P. Cambridge" accounts in the fol- 
lowing manner for the extreme smallness of the male in the 
genus Nephila. "M. Vinson gives a graphic account of the agile 
"way in which the diminutive male escapes from the ferocity of 
"the female, by gliding about and playing hide and seek over her 
"body and along her gigantic limbs: in such a pursuit it is evi- 
"dent that the chances of escape would be in favor of the smallest 
"males while the larger ones would fall early victims; thus grad- 
"ually a diminutive race of males would be selected, until at last 
"they would dwindle to the smallest possible size compatible with 
"the exercise of their generative functions, — in fact probably to 
* the size we now see them, i.e., so small as to be a sort of para- 
"site upon the female, and either beneath her notice, or too agile 
"and too small for her to catch without great difficulty." 

Westring has made the interesting discovery that the males 
ot several species of Theridion-^ have the power of making a 
strldulating sound, whilst the females are mute. The apparatus 
consists of a serrated ridge at the base of the abdomen, against 
which the hard hinder part of the thorax is rubbed; and of this 
structure not a trace can be detected in the females. It deserves 
notice that several writers, including the well-known arachnolo- 
gist Walckenaer, have declared that spiders are attracted by 
music.^* From the analogy of the Orthoptera and Homoptera, 
to be described in the next chapter, v/e may feel almost sure 
that the stridulation serves as Westring also believes, to call or to 
excite the female; and this is the first case known to me in the as- 
cending scale of the animal kingdom of sounds emitted for this 
purpose.^"* 

Class, Myriapoda. — In neither of the two orders in this class, 
the millipedes and centipedes, can I find any well-marked in- 
stances of such sexual differences as more particularly concern 
us. In Glomeris limbata, however, and perhaps in some few 
other species, the males differ slightly in color from the females; 
but this Glomeris is a highly variable species. In the males of 

21 Kirby and Spence, 'Introduction to Entomology,' vol. i. 1818, p. 280. 

22 'Proc. Zoolog. Soc.,' 1871, p. 621. 

23 Theridion (Asagena, Sund.) serratipes, 4-punctatum et guttatum; 
see Westring, in Kroyer, 'Naturhist. Tidskrift,' vol. iv. 1842-1843, p. 349; 
and vol. ii. 1846-1849, p. 342. See, also, for other species, 'Araneae 
Buecicae,' p. 184. 

2* Dr. H. H. van Zouteveen, in his Dutch translation of this work 
(vol. i. p. 444), has collected several cases. 

25 Hilgendorf, however, has lately called attention to an analogous 
structure in some of the higher crustaceans, which seems adapted to 
produce sound; see 'Zoological Record,' 1869, p. 603. 



SPIDERS. 271 

the Diplopoda, the legs belonging either to one of the anterior or 
of the posterior segments of the body are modified into prehensile 
hooks which serve to secure the female. In some species of lulus 
the tarsi of the male are furnished with membranous suckers for 
the same purpose. As we shall see when we treat of Insects, it is 
a much more unusual circumstance, that it is the female in Litho- 
bius, which is furnished with prehensile appendages at the ex- 
tremity of her body for holding the male.-^ 

28 Walckenaer et P. Gervais, 'Hist. Nat. des Insectes: Apteres,' 
torn. iv. 1847, pp. 17, 19, 68. 



372 THE DESCENT OF MAN. 



CHAPTER X. 

SECONDARY SEXUAL. CHARACTERS OF INSECTS. 

Diversified structures possessed by the males for seizing the females- 
Differences between the sexes, of which the meaning is not under- 
stood — Difference in size between the sexes — Thysanura— Diptera 
— Hemiptera — Homoptera, musical powers possessed by the males 
alone — Orthoptera, musical instruments of the males, much diver- 
sified in structure; pugnacity; colors— Neuroptera, sexual differ- 
ences in color— Hymenoptera, pugnacity and colors— Coleoptera, 
colors; furnished with great horns, apparently as an ornament; 
battles; stridulating organs generally common to both sexes. 

In the immense class of insects the sexes sometimes differ in 
their locomotive-organs, and often in their sense-organs, as in 
the pectinated and beautifully plumose antennae of the males of 
many species. In Chloeon, one of the Ephemera, the male has 
great pillared eyes, of which the female is entirely destitute.^ 
The ocelli are absent in the females of certain insects, as in the 
Mutillidse; and here the females are likewise wingless. But we 
are chiefly concerned with structures by which one male is en- 
abled to conquer another, either in battle or courtship, through 
his strength, pugnacity, ornaments, or music. The innumerable 
contrivances, therefore, by which the male is able to seize the fe- 
male, may be briefly passed over. Besides the complex struct- 
ures at the apex of the abdomen, which ought perhaps to be 
ranked as primary organs,^ "it is astonishing," as Mr. B. D. 

1 Sir J. Lubbock, 'Transact. Linnean Soc.,' vol. xxv. 1866, p. 484. 
With respect to the Mutillidae, see Westwood, 'Modern Class, of In- 
sects,' vol. ii. p. 213. 

2 These organs in the male often differ in clo-sely-allied species, and 
afford excellent specific characters. But their importance, from a 
functional point of view, as Mr. R. MacLachlan has remarked to me, 
has probably been overrated. It has been suggested, that slight dif- 
ferences in these organs would suffice to prevent the intercrossing of 
well-marked varieties or incipient species, and would thus aid in 
their development. That this can hardly be the case, we may infer 
from the many recorded cases (see, for instance, Bronn, 'Geschichte 
der Natur,' B. ii. 1843, s. 164; and Westwood, 'Transact. Ent. Soc.,* 



INSECTS. 273 

Walsh^ has remarked, "how many different organs are worked 
"in by nature for the seemingly insignificant object of enabling 
"the male to grasp the female firmly." The mandibles or jaws 
are sometimes used for this purpose; thus the male Corydalis 
cornutus (a neuropterous insect in some degree allied to the 
Dragon-flies, &c.) has immense curved jaws, many times longer 
than those of the female; and they are smooth instead of being 
toothed, so that he is thus enabled to seize her without injury.* 
One of the stag-^3eetles of North America (Lucanus elaphus) uses 
his jaws, which are much larger than those of the female, for the 
same purpose, but probably likewise for fighting. In one of the 
sand-wasps (Ammophila) the jaws in the two sexes are closely 
alike, but are used for widely different purposes: the males, as 
Professor Westwood observes, "are exceedingly ardent, seizing 
"their partners round the neck with their sickle-shaped jaws;"^ 
whilst the females use these organs for burrowing in sand-banks 
and making their nests. 

The tarsi of the front-legs are dilated in many male beetles, or 
are furnished with broad cushions of hairs; and in many genera 
of water-beetles they are armed with a round flat sucker, so that 
the male may adhere to the slippery body of the female. 
It is a much more unusual circumstance that the female 
of some water-beetles (Dytiscus) have their elytra deeply 
grooved, and in Acilius sulcatus thickly set with hairs, 
as an aid to the male. The females of some other 
water-beetles (Hydroporus) have their elytra punctured for 
the same purpose.^ In the male of Crabro cribrarius (fig. 
9), it is the tibia which is dilated into a broad horny plate, 
with minute membranous dots, giving to it a singular appear- 
ance like that of a riddle.^ In the male of Penthe (a genus of 

vol. iii. 1842, p. 195) of distinct species having- been observed in union. 
Mr. MacLacMan informs me (vide 'Stett. Ent. Zeitung,' 1867, s. 155) 
that when several species of Phryganidae, which present strongly- 
pronounced differences of this kind, were confined together by Dr. 
Aug. Meyer, they coupled, and one pair produced fertile ova. 

3 'The Practical Entomologist, Philadelphia, vol. ii. May, 1867, p. 88. 

*Mr. Walsh, ibid. p. 107. 

5 'Modern classification of Insects,' vol. ii. 1840, pp. 205, 206. Mr. 
Walsh, who called my attention to the double use of the jaws, says 
that he has repeatedly observed this fact. 

® We have here a curious and inexplicable case of dimorphism, for 
some of the females of four European species of Dytiscus, and of 
certain species of Hydroporus, have their elytra smooth; and no in- 
termediate gradations between the sulcated or punctured, and the 
quite smooth elytra have been observed. See Dr. H. Schaum, as 
quoted in the 'Zoologist,' vol. v.-vi. 1847-48, p. 1896. Also Kirby and 
Spence, 'Introduction to Entomology,' vol. iii. 1826, p. 305. 

7 Westwood, 'Modern Class, vol. ii. p. 193. The following statement 
19 



274 



THE DESCENT OF MAN. 



beetles) a few of the middle joints of the antennae are dilated and 
furnished on the inferior surface with cushions of hair, exactly 

like those on the tarsi of the Car- 
abidaB, "and obviously for the same 
end." In male dragon-flies, "the 
"appendages at the tip of the tail 
"are modified in an almost infinite 
"variety of curious patterns to en- 
"able them to embrace the neck of 
"the female." Lastly, in the males 
of many insects, the legs are fur- 
nished with peculiar spines, knobs 
or spurs; or the whole leg is bowed 
or thickened, but this is by no 
means invariably a sexual charac- 
ter; or one pair, or all three pairs 
are elongated, sometimes to an ex- 
travagant length.^ 

The sexes of many species in all 
the orders present differences, of 
which th© meaning is not under- 
stood. One curious case is that of a 
beetle (fig. 10), the male of which 
has the left mandible much en- 
larged; so that the mouth is greatly 
distorted. In another Carabidous beetle, Eurygnathus,^ we have 
the case, unique as far as known to Mr. Wollaston, of the head of 
the female being much broader and larger, though in a variable de- 
gree, than that of the male. Any number of such cases could be 
given. They abound in the Lepidoptera: one of the most extra- 
ordinary is that certain male butterflies have their fore-legs more 
or less atrophied, with the tibiae and tarsi reduced to mere rudi- 
mentary knobs. The wings, also, in the two sexes often differ in 
neuration,^*' and sometimes considerably in outline, as in the 
Aricoris epitus, which v/as shown to me in the British Museum 
by Mr. A. Butler. The males of certain South American butter- 
flies have tufts of hair on the margins of the wings, and horny 




Fig. 9. Crabro cribrarius. Up- 
per figure, male; lower fig- 
ure, female. 



about Penthe, and others in inverted commas, are taken from Mr. 
Walsh, 'Practical Entomologist,' Philadelphia, vol. ii. p. 88. 

8 Kirby and Spence, 'Introduct.' &c., vol. iii. pp. 332-336. 

» 'Insecta Maderensia,' 1854, p. 20. 

10 E. Doubleday, 'Annals and Mag. of Nat. Hist.' vol. i. 1848, p. 379. 
I may add that the wings in certain Hymenoptera (see Shuckard, 
'Fossorial Hymenop.' 1837, pp. 39-43) differ in neuration according to 
sex. 



INSECTS. 



275 



excrescences on the discs of the posterior pair." In several Brit- 
ish butterflies, as shown by Mr. Wonfor, the males alone are in 
parts clothed with peculiar scales. 

The use of the bright light of the female glow- 
worm has been subject to much discussion. The 
male is feebly luminous, as are the larvae and 
even the eggs. It has been supposed by some 
authors that the light serves to frighten away 
enemies, and by others to guide the male to the 
female. At last, Mr. Belt"' appears to have 
solved the difficulty: he finds that all the 
Lampyridse which he has tried are highly dis- 
tasteful to insectivorous mammals and birds. 
Hence it is in accordance with Mr. Bates' view, 
hereafter to be explained, that many insects 
mimic the Lampyridse closely, in order to be 
mistaken for them, and thus to escape destruc- 
tion. He further believes that the luminous 
species profit by being at once recognized as un- 
palatable. It is probable that the same explana- 
tion may be extended to the Elaters, both sexes 
of which are highly luminous. It is not known 
why the wings of the female glow-worm have 
not been developed; but in her present state she 
closely resembles a larva, and as larvae are so 
largely preyed on by many animals, we can un- 
derstand why she has been rendered so much 
more luminous and conspicuous than the male; 
and why the larvae themselves are likewise 
luminous. 





Difference in Size between the Sexes. —With 
insects of all kinds the males are commonly 
smaller than the females; and this difference 
can often be detected even in the larval state. 
So considerable is the difference between the 
male and female cocoons of the silk-moth (Bom- 
byx mori), that in France they are separated 
by a particular mode of weighing.^^ In the lower classes of the 
animal kingdom, the greater size of the females seems generally 



Fig-. 10. Taphro- 
deres distortus 
(much enlarg- 
ed). Upper fig-- 
u r e, male; 
lower figure, 
female. 



"H. W. Bates, in 'Journal of Proc. Linn. Soc' vol. vi. 1862, p. 74. 
Mr. Wonfor's observations are quoted in 'Popular Science Review,' 
1868, p. 343. 

12 'The Naturalist in Nicaragua,' 1874, pp. 316-320. On the phosphor- 
escence of the eggs, see 'Annals and Mag. of Nat. Hist.' 1871, Nov., 
p. 372. 

isRobinet, 'Vers a Sole,' 1848, p. 207. 



276 THE DESCENT OF MAN. 

to depend on their developing an enormous number of ova; and 
this may to a certain extent hold good with insects. But Dr. 
Wallace has suggested a much more probable explanation. He 
finds, after carefully attending to the development of the cater- 
pillars of Bombyx cynthia and yamamai, and especially to that 
of some dwarfed caterpillars reared from a second brood on un- 
natural food, "that in proportion as the individual moth is finer, 
"so is the time required for its metamorphosis longer; and for 
"this reason the female, which is the larger and heavier insect, 
"from having to carry her numerous eggs, will be preceded by the 
"male, which is smaller and has less to mature."" Now as most 
insects are short-lived, and as they are exposed to many dangers, 
it would manifestly be advantageous to the female to be impreg- 
nated as soon as possible. This end would be gained by the 
males being first matured in large numbers ready for the advent 
of the females; and this again would naturally follow, as Mr. A. 
R. Wallace has remarked,^^ through natural selection; for the 
smaller males would be first matured, and thus would procreate 
a large number of offspring which would inherit the reduced size 
of their male parents, whilst the larger males from being ma- 
tured later would leave fev/er offspring. 

There are, however, exceptions to the rule of male insects be- 
ing smaller than the females: and some of these exceptions are 
intelligible. Size and strength would be an advantage to the 
males, which fight for the possession of the females; and in these 
cases, as v/ith the stag-beetle (Lucanus), the males are larger 
than the females. There are, however, other beetles which are not 
known to fight together, of which the males exceed the females 
in size; and the meaning of this fact is not known; but in some 
of these cases, as with the huge Dynastes and Megasoma, we can 
at least see that there would be no necessity for the males to be 
smaller than the females, in order to be matured before them, for 
these beetles are not short-lived, and there would be ample time for 
the pairing of the sexes. So again, male dragon-fiies (Libellu- 
lidse) are sometimes sensibly larger, and never smaller, than the 
females;" and as Mr. MacLachlan believes, they do not generally 
pair with the females until a week or fortnight has elapsed, and 
until they have assumed their proper masculine colors. But the 
most curious cases, showing on what complex and easily over- 
looked relations, so trifling a character as difference in size be- 
tween the sexes may depend, is that of the aculeate Hymenop- 



" 'Transact. Ent. Soc' 3rd series, voL v. p. 486. 

IB 'Journal of Proc. Ent. Soc' Feb. 4th, 1867, p. Ixxi. 

16 For this and other statements on the size of the sexes, see Kirby 
and Spence, ibid. vol. iii. p. 300; on the duration of life in insects, 
see p. 344. 



^ THYSANURA. 27^ 

tera; for Mr. F. Smith informs me that throughout nearly the 
whole of this large group, the males, in accordance with the gen- 
eral rule, are smaller than the females, and emerge about a week 
before them; but amongst the Bees, the males of Apis mellifica, 
Anthidium manicatum, and Anthophora acervorum, and amongst 
the Fossores, the males of the Methoca ichneumonides, are larger 
than the females. The explanation of this anomaly is that a 
marriage flight is absolutely necessary with these species, and the 
male requires great strength and size in order to carry the female 
through the air. Increased size has here been acquired in oppo- 
sition to the usual relation between size and the period of de- 
velopment, for the males, though larger, emerge before tne 
smaller females. 

We will now review the several Orders, selecting such facts as 
more particularly concern us. The Lepidoptera (Butterflies and 
Moths) will be retained for a separate chapter. 

Order, Tliysanura.— The members of this lowly organized order 
are wingless, dull-colored, minute insects, with ugly, almost 
misshapen heads and bodies. Their sexes do not differ; but they 
are interesting as showing us that the males pay sedulous court 
to the females even low down in the animal scale. Sir J. Lub- 
bock^' says: "it is very amusing to see these little creatures 
"(Smynthurus luteus) coquetting together. The male, which is 
"much smaller than the female, runs round her, and they butt 
"one another, standing face to face, and moving backward and 
"forward like two playful lambs. Then the female pretends to 
"run away and the male runs after her with a queer appearance 
"of anger, gets in front and stands facing her again; then she 
"turns coyly round, but he, quicker and more active, scuttles 
"round too, and seems to whip her with his antennae; then for a 
"bit they stand face to face, play with their antennae, and seem 
"to be all in all to one another." 

Order, Diptera (Flies).— The sexes differ little in color. The 
greatest difference, known to Mr. F. Walker, is in the genus 
Bibio, in which the males are blackish or quite black, and the 
females obscure brownish-orange. The genus Elaphomyia, dis- 
covered by Mr. Wallace^^ in New Guinea, is highly remarkable, 
as the males are furnished with horns, of which the females are 
quite destitute. The horns spring from beneath the eyes, and 
curiously resemble those of a stag, being either branched or pal- 
mated. In one of the species, they equal the whole body in 
length. They might be thought to be adapted for fighting, but 
as in one species they are of a beautiful pink color, edged with 

"'Transact. Linnean Soc' vol. xxvi. 1868, p. 296. 
18 'The Malay Archipelago,' vol. iL 1869, p. 313. 
19 



278 THE DESCENT OF MAN. 

black, with a pale central stripe, and as these insects have alto- 
gether a very elegant appearance, it is perhaps more probable 
that they serve as ornaments. That the males of some Diptera 
fight together is certain; for Prof. Westwood^' has several times 
seen this with the Tipulae. The males of other Diptera appar- 
ently try to win the females by their music: H. Muller-o watched 
for some time two males of an Eristalis courting a female; they 
hovered above her, and flew from side to side, making a high 
humming noise at the same time. Gnats and mosquitoes (Culi- 
cidse) also seem to attract each other by humming; and Prof. 
Mayer has recently ascertained that the hairs on the antennae of 
the male vibrate in unison with the notes of a tuning-fork, within 
the range of the sounds emitted by the female. The longer 
hairs vibrate sympathetically with the graver notes, and the 
shorter hairs with the higher ones. Landois also asserts that he 
has repeatedly drawn down a whole swarm of gnats by uttering 
a particular note. It may be added that the mental faculties of 
the Diptera are probably higher than in most other insects, in ac- 
cordance with their highly developed nervous system.^^ 

Order, Hemiptera (Field-Bugs).— Mr. J. W. Douglas, who has 
particularly attended to the British species, has kindly given me 
an account of their sexual differences. The males of some species 
are furnished with wings, whilst the females are wingless; the 
sexes differ in the form of their bodies, elytra, antennae and tarsi; 
but as the signification of these differences are unknown they 
may be here passed over. The females are generally larger and 
more robust than the males. With British, and, as far as Mr. 
Douglas knows, with exotic species, the sexes do not commonly 
differ much in color; but in about six British species the male is 
considerably darker than the female, and in about four other 
species the female is darker than the male. Both sexes of some 
species are beautifully colored; and as these insects emit an 
extremely nauseous odor, their conspicuous colors may serve as 
a signal that they are unpalatable to insectivorous animals. In 
some few case their colors appear to be directly protective: thus 
Prof. Hoffmann informs me that he could hardly distinguish a 
small pink and green species from the buds on the trunks of lime- 
trees, which this insect frequents. 

Some species of Reduvidae makes a stridulating noise; and, in 



19 'Modern Classification of Insects,' vol. ii. 1840, p. 526, 

20 Anwendung, &c., 'Verb. d. n. V. Jahrg-.* xxix. p. 80. Mayer, in 
'American Naturalist,' 1874, p. 236. 

21 See Mr. B. T. Lowne's interesting work, 'On the Anatomy of the 
Blow-fly, Musca vomitoria,' 1870, p. 14. He remarks (p. 33) that, "the 
"captured flies utter a peculiar plaintive note, and that this sound 
"causes other flies to disappear." 



HEMIPTERA AND HOMOPTERA. 279 

the case of Pirates stridulus, this is said^^ to be effected by the 
movement of the neck within the pro-thoracic cavity. Accord- 
ing to Westring, Reduvius personatus also stridulates. But I 
have no reason to suppose that this is a sexual character, except- 
ing that with non-social insects there seems to be no use for 
sound-producing organs, unless it be as a sexual call. 

Order, Homoptera. — Every one who has wandered in a tropical 
forest must have been astonished at the din made by the male 
Cicadae. The females are mute; as the Grecian poet Xenarchus 
says, "Happy the Cicadas live, since they all have voiceless 
"wives." The noise thus made could be plainly heard on board 
the "Beagle," when anchored at a quarter of a mile from the 
shore of Brazil; and Captain Hancock says it can be heard at the 
distance of a mile. The Greeks formerly kept, and the Chinese 
now keep these insects in cages for the sake of their song, so that 
it must be pleasing to the ears of some men.-^' The Cicadidse 
usually sing during the day, whilst the Pulgoridae appear to be 
night-songsters. The sound, according to Landois,'* is produced 
by the vibration of the lips of the spiracles, which are set into 
motion by a current of air emitted from the tracheae but this view 
has lately been disputed. Dr. Powell appears to have proved-^ 
that it is produced by the vibration of a membrane, set into ac- 
tion by a special muscle. In the living insect, whilst stridulat- 
ing, this membrane can be seen to vibrate; and in the dead in- 
sect the proper sound is heard, if the muscle, when a little dried 
and hardened, is pulled with the point of a pin. In the female 
the whole complex musical apparatus is present, but is much less 
developed than in the male, and is never used for producing 
sound. 

With respect to the object of the music. Dr. Hartman, in 
speaking of the Cicada septemdecim of the United States, says,-® 
"the drums are now (June 6th and 7th, 1851) heard in all di- 
"rections. This I believe to be the marital summons from the 
"males. Standing in thick chestnut sprouts about as high as my 
"head, where hundreds were around me, I observed the females 
"coming around the drumming males." He adds, "this season 
"(Aug. 1868) a dwarf pear-tree in my garden produced about fifty 
"larvae of Cic. pruinosa; and I several times noticed the females 

22 Westwood, 'Modern Class, of Insects,' vol. ii. p. 473. 

23 These particulars are tsiken from Westwood's 'Modern Class, of 
Insects,' vol. ii. 1840, p. 422. See, also, on the Fulgoridae, Kirby and 
Spence, 'Introduct.' vol. ii. p. 401. 

2* 'Zeitschrift fur wissenschaft Zoolog-.' B. xvii. 1867, s. 152-158. 
25 'Transact. New Zealand Institute,' vol. v. 1873, p. 286. 
28 1 am indebted to Mr. Walsh for having sent me this extract from 
a 'Journal of the Doings of Cicada septemdecim,' by Dr. Hartman. 



2g0 THE DESCENT OF MAN. 

"to alight near a male while he was uttering his clanging notes." 
Fritz Miiller writes to me from S. Brazil that he has often lis- 
tened to a musical contest between two or three males of a species 
with a particularly loud voice, seated at a considerable distance 
from each other: as soon as one had finished his song, another 
immediately began, and then another. As there is so much ri- 
valry between the males, it is probable that the females not only 
find them by their sounds, but that, like female birds, they are 
excited or allured by the male with the most attractive voice. 

I have not heard of any well-marked cases of ornamental dif- 
ferences between the sexes of the Homoptera. Mr. Douglas in- 
forms me that there are three British species, in which the male 
is black or marked with black bands, whilst the females are pale- 
colored or obscure. 

Order, Orthoptera (Crickets and Grasshoppers). — The males in 
the three saltatorial families in this Order are remarkable for 
their musical powers, namely the Achetidse or crickets, the 
LocustidsB for which there is no equivalent English name, and 
the Acridiidae or grasshoppers. The stridulation produced by 
some of the Locustidse is so loud that it can be heard during the 
night at the distance of a mile;^^ and that made by certain species 
is not unmusical even to the human ear, so that the Indians on the 
Amazons keep them in wicker cages. All observers agree that 
the sounds serve either to call or excite the mute females. With 
respect to the migratory locusts of Russia, Korte has given^ an 
interesting case of selection by the female of a male. The males 
of this species (Pachytylus migratorius) whilst coupled with the 
female stridulate from anger or jealousy, if approached by other 
males. The house-cricket when surprised at night uses its voice 
to warn its fellows.-® In North America the Katy-did (Platy- 
phyllum concavum, one of the Locustidse) is described^ as mount- 
ing on the upper branches of a tree, and in the evening beginning 
"'his noisy babble, while rival notes issue from the neighboring 
"trees, and the groves resound with the call of Katy-did-she-did 
"the live-long night." Mr. Bates, in speaking of the European 
field-cricket (one of the Achetidse), says, "the male has been ob- 
"served to place himself in the evening at the entrance of his 
"burrow, and stridulate until a female approaches, when the 
"louder notes are succeeded by a more subdued tone, whilst the 

27 L. Guilding, 'Transact Linn. Soc' vol, xv. p. 154. 

2^ I state this on the authority of Koppen, 'Ueber die Heuschrecken 
in Sudrussland,' 1866, p. 32, for I have in vain endeavored to procure 
Korte' s work. 

2» Gilbert White, 'Nat. Hist, of Selborne,' vol. ii. 1825, p. 262. 

*» Harris, 'Insects of New England,' 1842, p. 128. 



ORTHOPTERA. 



281 



"successful musician caresses -with his antennae the mate he has 
"won."^^ Dr. Scudder was able to excite one of these insects to 
answer him by rubbing on a file with a quill.®- In both sexes a re- 
markable auditory apparatus has been discovered by Von Siebold, 
situated in the front legs.^^ 

In the three Families the sounds are differently produced. In 
the males of the Achetidae both wing-covers have the same ap- 
paratus; and this in the field-cricket (Gryllus campestris, fig. 11) 
consists, as described by Landois,^* of from 131 to 138 sharp, trans- 
verse ridges or teeth (st) on the under side of one of the nervures 





Fig-. 11. Gryllus campestris (from Landois). 

Rig-ht-hand figure, under side of part of a 

wing-nervure, much magnified, showing the 

teeth, St. 
Left-hand figure, upper surface of wing-cover, 

with the projecting, smooth nervure r, across 

which the teeth (st) are scraped. 



Fig. 12. Teeth of 
Nervure of Gryl- 
lus domesticus 
(from Landois). 



of the wing-cover. This toothed nervure is rapidly scraped across 
a projecting, smooth, hard nervure (r) on the upper surface of 
the opposite wing. First one wing is rubbed over the other, and 
then the movement is reversed. Both wings are raised a little 
at the same time, so as to increase the resonance. In some spe- 
cies the wing-covers of the males are furnished at the base with 
a talc-like plate.^" I here give a drawing (fig. 12) of the teeth 



31 'The Naturalist on the Amazons,' vol. i. 1863, p. 252. Mr, Bates 
gives a very interesting discussion on the gradations in the musical 
apparatus of the three families. See, also, Westwood, 'Modern 
Class.* vol. ii. pp. 445 and 453. 

32 'Proc. Boston Soc. of Nat. Hist.' vol. xi. April 1868. 

33 'Nouveau Manuel d'Anat. Comp.' (French translat.), torn. i. 1850, 
p. 567. 

a* 'Zeitschrift fur wissenschaft. Zoolog.' B. xvii. 1867, s. 117, 
^ Westwood, 'Modern Class, of Insects,' vol. i, p. 440, 



282 



THE DESCENT OF MAN. 



on the undftr side of the nervure of another species of Gryllus, 
viz., G. domeaticus. With respect to the formation of these teeth. 
Dr. Gruber has ehown^^ that they have been developed by the 
aid of selection, n^om the minute scales and hairs with which the 
wings and body sn e covered, and I came to the same conclusion 




Fig. 13. Chlorocoelus Tanana (from Bates). 

wing-covers. 



a, b. Lobes oi opposite 



with respect to those of the Coleoptera. But Dr. Gruber further 
shows that their development is in part directly due to the stim- 
ulus from the friction of one wing over the other. 

In the Locustidse the opposite wing-covers differ from each 
other in structure (fig. 13), and the action cannot, as in the last 
family, be reversed. The left wing, which acts as the bow, lies 
over the right wing which serves as the fiddle. One of the ner- 
vures (a) on the under surface of the former is finely serrated, 
and is scraped across the prominent nervures on the upper sur- 
face of the opposite or right wing. In our British Phasgonura 
viridissima it appeared to me that the serrated nervure is rubbed 



36 'Ueber der Tonapparat der Locustiden, ein Beitrag zum Darwin- 
ismus,' 'Zeitsch. fur wissensch. Zoolog.' B. xxii. 1872, p. 100. 



ORTHOPTERA. 283 

against the rounded hind-corner of the opposite wing, the edge 
of which is thickened, colored brown, and very sharp. In the 
right wing, but not in the left, there is a little plate, as transpar- 
ent as talc, surrounded by nervures, and called the speculum. In 
Ephippiger vitium, a member of the same family, we have a 
curious subordinate modification; for the wing-covers are great- 
ly reduced in size, but "the posterior part of the pro-thorax is 
"elevated into a kind of dome over the wing-covers, and which 
"has probably the effect of increasing the sound. "^' 

We thus see that the musical apparatus is more differentiated 
or specialized in the Locustidse (which include, I believe, the 
most powerful performers in the Order), than in the Achetidse, in 
which both wing-covers have the same structure and the same 
function.'*^ Landois, however, detected in one of the Locustidae, 
namely in Decticus, a short and narrow row of small teeth, mere 
rudiments, on the inferior surface of the right wing-cover, which 
underlies the other and is never used as the bow. I observed the 
same rudimentary structure on the under side of the right wing- 
cover in Phasgonura viridissima. Hence we may infer with con- 
fidence that the Locustidae are descended from a form, in which, 
as in the existing Achetidae, both wing-covers had serrated ner- 
vures on the under surface, and could be indifferently used as the 
bow; but that in the Locustidae the two wing-covers gradually 
became differentiated and perfected, on the principle of the divis- 
ion of labor, the one to act exclusively as the bow, and the other 
as the fiddle. Dr. Gruber takes the same view, and has shown 
that rudimentary teeth are commonly found on the inferior surface 
of the right wing. By what steps the more simple apparatus in 
the Achetidae originated, we do not know, but it is probable that 
the basal portions of the wing-covers originally overlapped each 
other as they do at present; and that the friction of the nervures 
produced a grating sound, as is now the case with the wing- 
covers of the females.^* A grating sound thus occasionally and 
accidentally made by the males, if it served them ever so little as 
a love-call to the females, might readily have been intensified 
through sexual selection, by variations in the raughness of the 
nervures having been continually preserved. 

In the last and third Family, namely the Aeridiidae or grass- 
hoppers, the stridulation is produced in a very different manner, 
and according to Dr. Scudder, is not so shrill as in the preceding 
Families. The inner surface ot the Femur (fig. 14, r) is fur- 
nished with a longitudinal row of minute, elegant, lancet-shaped, 

s'^ Westwood, 'Modern Class, of Insects,' vol. i. p. 453. 

38 Landois, 'Zeltsch. f. wiss. Zoolog.* B. xvii. 1867, s. 121, 122. 

8» Mr. Walsh also informs me that he has noticed that the female 
of the Platyphyllum concavum, "when captured makes a feeble grat- 
"ingr noise by shuffling her wiiag-covers togetheTo'' 



284 



THE DESCENT OF MAN. 




Fig. 14. Hind-leg of Stenoboth- 
rus pratorum: r, the stridu- 
lating ridge; lower figure, the 
teeth forming the ridge, much 
magnified (from Landois). 



elastic teeth, from 85 to 93 in number;*" and these are scraped 
across the sharp, projecting nervures on the wing-covers, which 

are thus made to vibrate and re- 
sound. Harris" says that when 
one of the males begins to play, 
he first "bends the shank of 
"the hind-leg beneath the thigh, 
"where it is lodged in a furrow 
"designed to receive it, and then 
"draws the leg briskly up and 
"down. He does not play both 
"fiddles together, but alternately, 
"first upon one and then on the 
"other." In many species, the 
base of the abdomen is hollowed 
out into a great cavity which is 
believed to act as a resounding 
board. In Pneumora (fig. 15), a 
S. African genus belonging to the 
same family, we meet with a 
new and remarkable modification; 
in the males a small notched 
ridge projects obliquely from each side of the abdomen, against 
which the hind femora are rubbed.*^ As the male is furnished 
with wings (the female being wingless), it is remarkable that the 
thighs are not rubbed in the usual manner against the wing- 
covers; but this may perhaps be accounted for by the unusually 
small size of the hind-legs. I have not been able to examine the 
inner surface of the thighs, which, judging from analogy, would 
be finely serrated. The species of Pneumora have been more pro- 
foundly modified for the sake of stridulation than any other 
orthopterous insect; for in the male the whole body has been 
converted into a musical instrument, being distended with air, 
like a great pellucid bladder, so as to increase the resonance. 
Mr. Trimen informs me that at the Cape of Good Hope these 
insects make a wonderful noise during the night. 

In the three foregoing families, the females are almost always 
destitute of an efiicient musical apparatus. But there are a few 
exceptions to this rule, for Dr. Gruber has shown that both sexes 
of Ephippiger vitium are thus provided; though the organs differ 
in the male and female to a certain extent. Hence we cannot 
suppose that they have been transferred from the male to the 
female, as appears to have been the case with the secondary sexual 



40 Landois, ibid. s. 113. 

*i 'Insects of New England,' 1842, p. 133. 

*2'WeBtwood, 'Modem Classification,' vol. 



i. p. 462. 



ORTHOPTERA. 



285 



characters of many other animals. They must have been inde- 
pendently developed in the two sexes, which no doubt mutually 
call to each other during the season of love. In most other Lo- 
custidse (but not according to Landois in Decticus) the females 




Fig. 15. Pneumora (from specimens in the British Museum). Upper 
figure, male; lower figxire, female. 

have rudiments of the stridulatory organs proper to the male; 
from whom it is probable that these have been transferred. Lan- 
dois also found such rudiments on the under surface of the wing- 
covers of the female Achetidse, and on the femora of the female 
Acridiidse. In the Homoptera, also, the females have the proper 
musical apparatus in a functionless state; and we shall hereafter 
meet in other divisions of the animal kingdom with many in- 
stances of structures proper to the male being present in a rudi- 
mentary condition in the female. 



286 THE DESCENT OF MAN. 

Landois has observed another important fact, namely, that in 
the females of the Acridiidae, the stridulating teeth on the femora 
remain throughout life in the same condition in which they first 
appear during the larval state in both sexes. In the males, on 
the other hand, they become further developed, and acquire their 
perfect structure at the last moult, when the insect is mature and 
ready to breed. 

From the facts now given, we see that the means by which 
the males of the Orthoptera produce their sounds are extremely 
diversified, and are altogether different from those employed by 
the Homoptera.*^ But throughout the animal kingdom we often 
find the same object gained by the most diversified means; this 
seems due to the whole organization having undergone multifari- 
ous changes in the course of ages, and as part after part varied 
different variations were taken advantage of for the same general 
purpose. The diversity of means for producing sound in the three 
families of the Orthoptera and in the Homoptera, impresses the 
mind with the high importance of these structures to the males, 
for the sake of calling or alluring the females. We need feel 
no surprise at the amount of modification which the Orthoptera 
have undergone in this respect, as we now know, from Dr. Scud- 
der's remarkable discovery,** that there has been more than ample 
time. This naturalist has lately found a fossil insect in the 
Devonian formation of New Brunswick, which is furnished with 
"the well-known tympanum or stridulating apparatus of the male 
"Locustidae." The insect, though in most respects related to the 
Neuroptera, appears, as is so often the case with very ancient 
forms, to connect the two related Orders of the Neuroptera and Or- 
thoptera. 

I have but little more to say on the Orthoptera. Some of the 
species are very pugnacious: when two male field-crickets 
(Gryllus campestris) are confined together, they fight till one kills 
the other; and the species of Mantis are described as maneuvering 
with their sword-like front-limbs, like hussars with their sabres. 
The Chinese keep these insects in little bamboo cages, and match 
them like game-cocks.*^ With respect to color, some exotic locusts 
are beautifully ornamented; the posterior wings being marked 
with red, blue, and black; but as throughout the Order the sexes 
rarely differ much in color, it is not probable that they owe their 

*3 Landois has recently found in certain Orthoptera rudimentary 
structures closely similar to the sound-producing organs in the Ho- 
moptera; and this is a surprising fact. See 'Zeitschr, fur wissensch. 
Zoolog.' B. xxii. Heft 3, 1871, p. 348. 

** 'Transact. Ent. Soc' 3rd series, vol. ii. ('Journal of Proceedings," 
p. 117.) 

^ Westwood. 'Modem Class, of Insects,' vol. i. p. 427; for crickets, 
p. 445. 



ORTHOPTERA. 287 

bright tints to sexual selection. Conspicuous colors may be of 
use to these insects, by giving notice that they are unpalatable. 
Thus it has been observed*^ that a bright-colored Indian locust 
was invariably rejected when offered to birds and lizards. Some 
cases, however, are known of sexual differences in color in this 
Order. The male of an American cricket*^ is described as being as 
white as ivory, whilst the female varies from almost white to 
greenish-yellow or dusky. Mr. Walsh informs me that the adult 
male of Spectrum femoratum (one of the Phasmidse) "is of a shin- 
ning brownish-yellow color; the adult female being of a dull, 
"opaque, cinereous brown; the young of both sexes being green." 
Lastly, I may mention that the male of one curious kind of 
cricket*® is furnished with "a long membranous appendage, which 
"falls over the face like a veil;" but what its use may be, is not 
known. 

Order, Neuroptera. — Little need here be said, except as to color. 
In the Ephemeridae the sexes often differ slightly in their ob- 
scure tints;*'' but it is not probable that the males are thus ren- 
dered attractive to the females. The Libellulidse, or dragon-flies, 
are ornamented with splendid green, blue, yellow, and vermilion 
metallic tints; and the sexes often differ. Thus, as Prof. West- 
wood remarks,^" the males of some of the Agrionidas, "are of a 
-■'rich blue with black wings, whilst the females are fine green with 
"colorless wings." But in Agrion Ramburii these colors are ex- 
actly reversed in the two sexes.^^ In the extensive N. American 
genus of Het^rina, the males alone have a beautiful carmine spot 
at the base of each wing. In Anax Junius the basal part of the 
abdomen in the male is a vivid ultramarine blue and in the fe- 
male grass-green. In the allied genus Gomphus, on the other 
hand, and in some other genera, the sexes differ but little in 
color. In closely-allied forms throughout the animal king- 
dom, similar cases of the sexes differing greatly, or very 
little, or not at all, are of frequent occurrence. Although there is 
so wide a difference in color between the sexes of many Libel- 
lulidse, it is often difficult to say which is the more brilliant; and 
the ordinary coloration of the two sexes is reversed, as we have 
just seen, in one species of Agrion. It is not probable that their 

^8 Mr. Ch. Home, in 'Proc. Ent. Soc' May 3, 1869, p. xii. 

*' The Oecanthus nivalis. Harris, 'Insects of New England,' 1842, 
p. 124. The two sexes of Oe. pellucidus of Europe differ, as I hear 
from Victor Carus, in nearly the same manner. 

*8 Platyblemnus : "Westwood, 'Modem Class.' vol. i. p. 447. 

*» B. D. Walsh, the 'Pseudo-neuroptera of Illinois,' in 'Proc. Ent. 
Soc. of Philadelphia,' 1862, p. 361. 

so 'Modern Class.' vol. ii. p. 37. 

SI Walsh, ibid. p. 381. I am indebted to this naturalist for the fol- 
lowing facts on Hetaerina, Anax, and Gomphus. 



2S8 THE DESCENT OF MAN. 

colors in any case have been gained as a protection. Mr. Mac- 
Lachlan, who has closely attended to this family, writes to me 
that dragon-flies— tho tyrants of the Insect-world— are the least 
liable of any insect to be attacked by birds or other enemies, and 
he believes that their bright colors serve as a sexual attraction. 
Certain dragon-flies apparently are attracted by particular colors: 
Mr. Patterson observed" that ihe Agrionidae, of which the males 
are blue, settled in numbers on the blue float of a fishing line; 
whilst two other species were attracted by shining white colors. 

It is an interesting fact, first noticed by Schelver, that in sev- 
eral genera belonging to two sub-families, the males on first 
emergence from the pupal state, are colored exactly like the 
females; but that their bodies in a short time assume a con- 
spicuous milky-blue tint, owing to the exudation of a kind of oil, 
soluble in ether and alcohol. Mr. MacLachlan believes that in 
the male of Libellula depressa this change of color does not occur 
until nearly a fortnight after the metamorphosis, when the sexes 
are ready to pair. 

Certain species of Neurothemis present, according to Brauer,''* 
a curious case of dimorphism, some of the females having ordinary 
wings, whilst others have them "very richly netted, as in the 
"males of the same species." Brauer "explains the phenomenon 
**on Darwinian principles by the supposition that the close net- 
"ting of the veins is a secondary sexual character in the males, 
"which has been abruptly transferred to some of the females, 
"instead of, as generally occurs, to all of them." Mr. MacLachlan 
informs me of another instance of dimorphism in several species 
of Agrion, in which some individuals are of an orange color, and 
these are invariably females. This is probably a case of rever- 
sion; for in the true Libellulse, when the sexes differ in color, 
the females are orange or yellow; so that supposing Agrion to be 
descended from'some primordial form which resembled the typi- 
cal Libellulae in its sexual characters, it would not be surprising 
that a tendency to vary in this manner should occur in the fe- 
males alone. 

Although many dragon-flies are large, powerful, and fierce in- 
sects, the males have not been observed by Mr. MacLachlan to 
fight together, excepting, as he believes, in some of the smaller 
species of Agrion. In another group in this Order, namely, the 
Termites or white ants, both sexes at the time of swarming may 
be seen running about, "the male after the female, sometimes 
"two chasing one female, and contending with great eagerness 
"who shall win the prize."^* The Atropos pulsatorius is said to 

52 'Transact. Ent. Soc' vol, i. 1836, p. Ixxxi. 

53 See abstract in the 'Zoological Record,' for 1867, p. 450. 
"Kirby and Spence, 'Introduct. to Entomology,' vol. ii. 1818, p., 35. 



HYMENOPTERA. 289 

make a noise with its jaws, which is answered by other indi- 
viduals/' 

Order, Hymenoptera. — That inimitable observer, M. Fabre/« in 
describing the habits of Cereeris, a wasp-like insect, remarks that 
"fights frequently ensue between the males for the possession of 
"some particular female, who sits an apparently unconcerned be- 
"holder of the struggle for supremacy, and when the victory is 
"decided, quietly flies away in company with the conqueror." 
Westwood^^ says that the males of one of the saw-flies (Tenthre- 
din^) "have been found fighting together with their mandibles 
"locked." As M. Fabre speaks of the males of Cereeris striving 
to obtain a particular female, it may be well to bear in mind 
that insects belonging to this Order have the power of recognizing 
each other after long intervals of time, and are deeply attached. 
For instance, Pierre Huber, whose accuracy no one doubts, sep- 
arated some ants, and when, after an interval of four months, 
they met others which had formerly belonged to the same com- 
munity, they recognized and caressed one another with their 
antennas. Had they been strangers they would have fought to- 
gether. Again, when two communities engage in a battle, the 
ants on the same side sometimes attack each other in the general 
confusion, but they soon perceive their mistake, and the one ant 
soothes the other.^® 

In this Order slight differences in color, according to sex, are 
common, but conspicuous differences are rare except in the fam- 
ily of Bees; yet both sexes of certain groups are so brilliantly 
colored — for instance in Chrysis, in which vermilion and metallic 
greens prevail — that we are tempted to attribute the result to 
sexual selection. In the Ichneumonidse, according to Mr. Walsh,^' 
the males are almost universally lighter-colored than the females. 
On the other hand, in the Tenthredinidae the males are generally 
darker than the females. In the Siricidae the sexes frequently dif- 
fer; thus the male of Sirex juvencus is banded with orange, 
whilst the female is dark purple; but it is diflacult to say which 
sex is the more ornamented. In Tremex columbae the female is 
much brighter colored than the male. I am informed by Mr. F. 
Smith, that the male ants of several species are black, the females 
being testaceous. 

In the family of Bees, especially in the solitary species, as I 

^ Houzeau, 'Les Facultes Men tales,' &c. Tom. i. p. 104. 

^ See an interesting article, 'The Writings of Fabre,' in 'Nat. Hist. 
Review,' April, 1862, p. 122. 

E7 'Journal of Proc. of Entomolog. Soc' Sept. 7th, 1863, p. 169. 

^ P. Huber, 'Recherches sur les Moeurs des Fourmis,' 1810, pp. ISflt 
165. 

5» 'Proc. Entomolog-. Soc. of Philadelphia,' 1866, pp. 238-239. 
20 



290 THE DESCENT OF MAN. 

hear from the same entomologist, the sexes often differ in color. 
The males are generally the brighter, and in Bombus as well as in 
Apathus, much more variable in color than the females. In 
Anthophora retusa the male is of a rich fulvous-brown, whilst the 
female is quite black; so are the females of several species of 
Xylocopa, the males being bright yellow. On the other hand the 
females of some species, as of Andrsena fulva, are much brighter- 
colored than the males. Such differences in color can hardly be 
accounted for by the males being defenseless and thus requiring 
protection, whilst the females are well defended by their stings. 
H. Muller,"^" who has particularly attended to the habits of bees, 
attributes these differences in color in chief part to sexual selec- 
tion. That bees have a keen perception of color is certain. He 
says that the males search eagerly and fight for the possession 
of the females; and he accounts through such contests for the 
mandibles of the males being in certain species larger than those 
of the females. In some cases the males are far more numerous 
than the females, either early in the season, or at all times and 
places, or locally; whereas the females in other cases are appar- 
ently in excess. In some species the more beautiful males appear 
to have been selected by the females; and in others the more beau- 
tiful females by the males. Consequently in certain genera (Miil- 
ler, p. 42), the males of the several species differ much in appear- 
ance, whilst the females are almost indistinguishable; in other 
genera, the reverse occurs. H. Miiller believes (p. 82) that the 
colors gained by one sex through sexual selection have often been 
transferred in a variable degree to the other sex, just as the pollen- 
collecting apparatus of the female has often been transferred to 
the male, to whom it is absolutely useless.^^ 



6» 'Anwendung der Darwinschen Lehre auf Bienen.' Verb. d. n. 
Jahrg. xxix. 

61 M. Perrier in his article 'la Selection sexuelle d'apres Darwin* 
('Revue Scientifique,' Feb. 1873, p. 868), without apparently having- re- 
flected much on the subject, objects that as the males of social bees 
are known to be produced from unfertilized ova, they could not trans- 
mit new characters to their male offspring. This is an extraordinary 
objection. A female bee fertilized by a male, which presented some 
character facilitating the union of the sexes, or rendering him more 
attractive to the female, would lay eggs which would produce only 
females; but these young females would next year produce males; 
and will it be pretended that such males would not inherit the char- 
acters of their male grandfathers? To take a case with ordinary 
animals as nearly parallel as possible: if a female of any white 
quadruped or bird were crossed by a male of a black breed, and the 
male and female offspring were paired together, will it be pretended 
that the grandchildren would not inherit a tendency to blackness 
from their male grandfather? The acquirement of new characters 
by the sterile warker-bees is a much more difficult case, but I have 



COLEOPTERA. 291 

Mutilla EuropaBa makes a stridulating noise; and according to 
Goureau^^ both sexes have this power. He attributes the sound 
to the friction of the third and preceding abdominal segments, 
and I find that these surfaces are marked with very fine con- 
centric ridges; but so is the projecting thoracic collar, into which 
the head articulates, and this collar, when scratched with the 
point of a needle, emits the proper sound. It is rather surprising 
that both sexes should have the power of stridulating, as the 
male is winged and the female wingless. It is notorious that 
Bees express certain emotions, as of anger, by the tone of their 
humming; and according to H. Miiller (p. 80), the males of some 
species makes a peculiar singing noise wnilst pursuing the females. 

Order, Coleoptera (Beetles). — Many beetles are colored so as 
to resemble the surfaces which they habitually frequent, and 
they thus escape detection by their enemies. Other species, for 
instance diamond-beetles, are ornamented with splendid colors, 
which are often arranged in stripes, spots, crosses, and other 
elegant patterns. Such colors can hardly serve directly as a 
protection, except in the case of certain flower-feeding species; 
but they may serve as a warning or means of recognition, on the 
same principle as the phosphorescence of the glow-worm. As 
with beetles the colors of the two sexes are generally alike, we 
have no evidence that they have been gained through sexual 
selection; but this is at least posible, for they may have been 
developed in one sex and then transferred to the other; and 
this view is even in some degree probable in those groups which 
possess other well-marked secondary sexual characters. Blind 
beetles, which cannot of course behold each other's beauty, never, 
as I hear from Mr. Waterhouse, jun., exhibit bright colors, 
though they often have polished coats; but the explanation of 
their obscurity may be that they generally inhabit caves and 
other obscure stations. 

Some Longicorns, especially certain Prionid^, offer an excep- 
tion to the rule that the sexes of beetles do not differ in color. 
Most of these insects are large and splendidly colored. The 
males in the genus Pyrodes,**^ which I saw in Mr. Bates's collec- 

endeavored to show in my 'Origin of Species,' how these sterile be- 
ings are subjected to the power of natural selection. 

^2 Quoted by Westwood, 'Modern Class, of Insects,' vol. ii. p. 214. 

^ Pyrodes pulcherrimus, in which the sexes differ conspicuously, 
has been described by Mr. Bates in 'Transact. Ent. Soc' 1869, p. 50. I 
will specify the few other cases in which I have heard of a differ- 
ence in color between the sexes of beetles. Kirby and Spence ('In- 
troduct. to Entomology,' vol. iii. p. 301) mention a Cantharis, Meloe, 
Ehagium, and the Leptura testacea; the male of the latter being tes- 
taceous, with a black thorax, and the female of a dull red all over. 
These two latter beetles belong to the family of Longicorns. Messrs. 



292 



THE DESCENT OF MAN. 



tion, are generally redder but rather duller than the females, the 
latter being colored of a more or less splendid golden-green. On 
the other hand, in one species the male is golden-green, the female 
being richly tinted with red and purple. In the genus Esmeralda 
the sexes differ so greatly in color that they have been ranked 
as distinct species; in one species both are of a beautiful shin- 
ing green, but the male has a red thorax. On the whole, as far 




Fig. 16. Chalcosoma atlas. Upper figure, male (reduced); lower 
figure, female (natural size). 

as I could judge, the females of those Prionidse, in which the sexes 
differ, are colored more richly than the males, and this does not 
accord with the common rule in regard to color, when acquired 
through sexual selection. 

A most remarkable distinction between the sexes of many 
beetles is presented by the great horns which rise from the head, 
thorax, and clypeus of the males; and in some few cases from 
the under surface of the body. These horns, in the great family 
of the Lamellicorns, resemble these of various quadrupeds, such 



R. Trim en and Waterhouse, jun., inform me of two Lamellicorns, 
viz., a Peritrichia and Triohius, the male of the latter being more 
obscurely colored than the female. In Tillus elongatus the male is 
black, and the female always, as it is believed, of a dark blue color, 
with a red thorax. The male, also, of Orsodacna atra, as I hear from 
Mr. Walsh, is black, the female (the so-called O. ruficoUis) having a 
rufous thorax. 



COLEOPTERA. 



293 




Fig-. 17. Copris isidis. (Left-hand figures, males.) 




Fig. 20. 



Onthophagus rangifer, enlarged. 



'K) 



294 TK23 DESCENT OF MAN. 

as stags, rhinoceroses, &c., and are wonderful both from their 
size and diversified shapes. Instead of describing them, I have 
given figures of the males and females of some of the more re- 
markable forms. (Figs. 16 to 20.) The females generally ex- 
hibit rudiments of the horns in the form of small knobs or ridges; 
but some are destitute of even the slightest rudiment. On the 
other hand, the horns are nearly as well developed in the female 
as in the male of Phanasus lancifer; and only a little less well 
developed in the females of some other species of this genus and 
of Copris. I am informed by Mr. Bates that the horns do not 
differ in any manner corresponding with the more important char- 
acteristic differences between the several subdivisions of the 
family: thus within the same section of the genus Onthophagus, 
there are species which have a single horn, and others which 
have two. 

In almost all cases, the horns are remarkable from their ex- 
cessive variability; so that a graduated series can be formed, 
from the most highly developed males to others so degenerate 
that they can barely be distinguished from the females. Mr. 
Walsh^* found that in Phanaeus carnifex the horns were thrice as 
long in some males as in others. Mr. Bates, after examining 
above a hundred males of Onthophagus rangifer (fig. 20), thought 
that he had at last discovered a species in which the horns did 
not vary; but further research proved the contrary. 

The extraordinary size of the horns, and their widely different 
structure in closely-allied forms, indicate that they have been 
formed for some purpose; but their excessive variability in the 
males of the same species leads to the inference that this purpose 
cannot be of a definite nature. The horns do not show marks of 
friction, as if used for any ordinary work. Some authors sup- 
pose®^ that as the males wander about much more than the fe- 
males, they require horns as a defense against their enemies; but 
as the horns are often blunt, they do not seem well adapted for 
defense. The most obvious conjecture is that they are used by 
the males for fighting together; but the males have never been 
observed to fight; nor could Mr. Bates, after a careful exam- 
ination of numerous species, find any suflicient evidence, in thei^ 
mutilated or broken condition, of their having been thus used. 
If the males had been habitual fighters, the size of their bodies 
would probably have been increased through sexual selection, 
so as to have exceeded that of the females; but Mr. Bates, after 
comparing the two sexes in above a hundred species of the 
Copridae, did not find any marked difference in this respect 
amongst well-developed individuals. In Lethrus, moreover, a bee- 

«* 'Proc. Entomolog. Soc. of Philadelphia,' 1864, p. 228. 

65 Kirby and f-ipence, 'Introduct. Entomolog-.' vol. iii. p. 300. 



COLEOPTERA. 



295 



tie belonging to the same great division of the Lamellicorns, the 
males are known to fight, but are not provided with horns, though 
their mandibles are much larger than those of the female. 

The conclusion that the horns have been acquired as ornaments 
is that which best agrees with the fact of their having been so 
immensely, yet not fixedly, developed,— as shown by their extreme 
variability in the same species, and by their extreme diversity in 
closely-allied species. This view will at first appear extremely 
improbable; but we shall hereafter find with many animals stand- 
ing much higher in the scale, namely fishes, amphibians, reptiles 
and birds, that various kinds of crests, knobs, horns and combs 
have been developed apparently for this sole purpose. 

The males of Onitis furcifer (fig. 21), and of 
some other .species of the genus, are furnished 
with singular projections on their anterior fe- 
mora, and with a great fork or pair of horns on 
the lower surface of the thorax. Judging from 
other insects, these may aid the male in clinging 
to the female. Although the males have not 
even a trace of a horn on the upper surface of 
the body, yet the females plainly exhibit a rudi- 
21. Onitis ^^^^ of a single horn on the head (fig. 22, a), 
male and of a crest (b) on the thorax. That the 
slight thoracic crest in the female is a rudiment 
of a projection proper to the male, though en- 
tirely absent in the males of this particular species, is clear: 
for the female of Bubas bison (a genus which comes 
next to Onitis) has a similar slight crest on the thorax. 




Fig. 
furcifer, 
viewed from be 
neath. 





Fig. 22. Left-hand figure, male of Onitis furcifer, viewed laterally. 

Right-hand figure, female, a. Rudiment of cephalic horn. 

b. Trace of thoracic horn or crest. 

and the male bears a great projection in the same situa- 
tion. So, again, there can hardly be a doubt that the little point 
(a) on the head of the female Onitis furcifer, as well as on the 
head of the females of two or three allied species, is a rudimentary 
representative of the cephalic horn, which is common to the 
males of so many Lamellicorn beetles, as in Ph^tnseus (fig. 18). 
The old belief that rudiments have been created to complete the 



296 THE DESCENT OF MAN. 

scheme of nature is here r^o far from holding good, that we have 
a complete inversion of the ordinary state of things in the family. 
We may reasonably suspect that the males originally bore horns 
and transferred them to the females in a rudimentary condition, 
as in so many other Lamellicorns. Why the males subsequently 
lost their horns, we know not; but this may have been caused 
through the principle of compensation, owing to the development 
of the large horns and projections on the lower surface; and as 
these are confined to the males, the rudiments of the upper horns 
on the females would not have been thus obliterated. 

The cases hitherto given refer to the Lamellicorns, but the males 
of some few other beetles, belonging to two widely distinct groups, 
namely, the Curculionidse and Staphylinidae, are furnished with 
horns — in the former on the lower surface of the body,*^^ in the 
latter on the upper surface of the head and thorax. In the Staphy- 
linidse, the horns of the males are extraordinarily variable in the 
same species, just as we have seen with the Lamellicorns. In 
Siagonium we have a case of dimorphism, for the males can be 
divided into two sets, differing greatly in the size of their bodfes 
and in the development of their horns, without intermediate 
gradations. In a species of Bledius (fig. 23), also belonging to the 





Fig. 23. Bledius taurus, magnified. Left-hand figure, male; right- 
hand figure, female. 

Staphylinidae, Professor Westwood states that, "male specimens 
"can be found in the same locality in which the central horn of 
"the thorax is very large, but the horns of the head quite rudi- 
"mental; and others, in which the thoracic horn is much shorter, 
"whilst the protuberances on the head are long."" Here we ap- 
parently have a case of compensation, which throws light on that 
just given of the supposed loss of the upper horns by the males of 
Onitis. 

Law of Battle. -^Some male beetles, which seem ill-fitted for 
fighting, nevertheless engage in conflicts for the possession of the 
females. Mr. Wallace®* saw two males of Leptorhynchus angusta- 

«« Kirby and Spence, 'Introduct. Entomolog.' vol. iii. p. 329. 

^7 'Modern Classification of Insects,' vol. i. p. 172: Siagonium, p. 172. 
In the British Museum I noticed one male specimen of Siagonium in 
an intermediate condition, so that the dimorphism is not strict. 

«8 'The Malay Archipelago,' vol. ii. 1869, p. 276. Riley, Sixth 'Re- 
port on insects of Missouri,' 1874, p. 115. 



COLEOPTERA. 297 

tus, a linear beetle with a much elongated rostrum, "fighting for 
"a female, who stood close by busy at her boring. They pushed 
"at each other with their rostra, and clawed and thumped, ap- 
"parently in the greatest rage." The smaller male, however, 
"soon ran away, acknowledging himself vanquished." In some 
few cases male beetles are well adapted for fighting, by possess- 
ing great toothed mandibles, much larger than those of the fe- 
males. This is the case with the common stag-beetle (Lucanus 
cervus), the males of which emerge from the pupal state about a 
week before the other sex, so that several may often be seen 
pursuing the same female. At this season they engage in fierce 
conflicts. When Mr. A. H. Davis*^* enclosed two males with one 
female in a box, the larger male severely pinched the smaller one, 
until he resigned his pretensions. A friend informs me that when 
a boy he often put the males together to see them fight, and he 
noticed that they were much bolder and fiercer than the females, 
as with the higher animals. The males would seize hold of his 
finger, if held in front of them, but not so the females, although 
they have stronger jaws. The males of many of the Lucanidse, as 
well as of the above-mentioned Leptorhynchus, are larger and 
more powerful insects than the females. The two sexes of Le- 
thrus cephalotes (one of the Lamellicorns) inhabit the same bur- 
row; and the male has larger mandibles than the female. If, dur- 
ing the breeding-season, a strange male attempts to enter the bur- 
row, he is attacked; the female does not remain passive, but closes 
the mouth of the burrow, and encourages her mate by continually 
pushing him on from behind; and the battle lasts until the ag- 
gressor is killed or runs away.^° The two sexes of another 
Lamellicorn beetle, the Ateuchus cicatricosus, live in pairs, and 
seem much attached to each other; the male excites the female to 
roll the ball of dung in which the ova are deposited; and if she is 
removed, he becomes much agitated. If the male is removed the 
female ceases all work, and as M. Brulerie'^ believes, would remain 
on the same spot until she died. 

The great mandibles of the male Luscanidse are extremely va- 
riable both in size and structure, and in this respecet resemble 
the horns on the head and thorax of many male Lamellicorns and 
Staphylinidae. A perfect series can be formed from the best-pro- 
vided to the worst-provided or degenerate males. Although the 
mandibles of the common stag-beetle, and probably of many other 
species, are used as efficient weapons for fighting, it is doubtful 

«» 'Entomological Magazine,' vol. i. 1833, p. 82. See, also, on the 
conflicts of this species, Kirby and Spence, ibid, vol. iii. p. 314; and 
Westwood, ibid. vol. i. p. 187. 

^0 Quoted from Fischer, in 'Diet. Class. d'Hist. Nat.' tom. x. p. 324. 

7^ 'Ann. Soc. Entomolog. France,' 1866, as quoted in 'Journal of 
Travel,' by A. Murray, 1868, p. 135. 



298 



THE DESCENT OF MAN. 



whether their great size can thus be accounted for. We have seen 
that they are used by the Lucanus elaphus of N. America for seiz- 
ing the female. As they are so conspic- 
uous and so elegantly branched, and as 
owing to their great length they are not 
well adapted for pinching, the suspicion 
has crossed my mind that they may in 
addition serve as an ornament, like the 
horns on the head and thorax of the 
various species above described. The 
male Chiasognathus Grantii of S. Chile 
— a splendid beetle belonging to the 
same family — has enormously developed 
mandibles (iig. 24) ; he is bold and pugna- 
cious; when threatened he faces round, 
opens his great jaws, and at the same 
time stridulates loudly. But the mandi- 
bles were not strong enough to pinch my 
linger so as to cause actual pain. 

Sexual selection, which implies the pos- 
session of considerable perceptive powers 
and of strong passions, seems to have 
been more effective with the Lamellicorna 
than with any other family of beetles. 
With bome species the males are provided 
J p \ with weapons for fighting; some live in 

^ if ^ I pairs and show mutual affection; many 

have the power of stridulating when ex- 
cited; many are furnished with the most 
extraordinary horns, apparently for the 
sake of ornament; and some, which are 
diurnal in their habits, are gorgeously 
colored. Lastly, several of the largest 
beetles in the world belong to this fam- 
ily, which was placed by Linnaeus and 
Fabricius at the head of the Order.^^ 




Fig". 24. Chiasognathus 



Stridulating organs. — Beetles belonging 
to many and widely distinct families pos- 
sess these organs. The sound thus pro- 



grantii, reduced, 
per figrire, male; 
er figure, female. 



Up- duced can sometimes be heard at the dis- 



low- 



tance of several feet or even yards,''^ 
but it is not comparable with that 



made by the Orthoptera. The rasp generally consists of 



'2 Westwood, 'Modern Class.' vol. 1. p. 184. 

7s Wollaston, 'On certain Musical Curculionidae,' 'Annals and Mag. 
of Nat. Hist., vol. vi. 1860, p. 14. 



COLEOPTERA. 



2^9 



a narrow, slightly-raised surface, crossed by very fine, par- 
allel ribs, sometimes so fine as to cause irridescent colors, 
and having a very elegant appearance under the micro- 
scope. In some cases, as with Typhceus, minute, bristly or 
scale-like prominences, with which the whole surrounding surface 
is covered in approximately parallel lines, could be traced passing 
into the ribs of the rasp. The transition takes place by their be- 
coming confluent and straight, and at the same time more promi- 
nent and smooth. A hard ridge on an adjoining part of the body 
serves as the scraper for the rasp, but this scraper in some cases 
has been specially modified for the purpose. It is rapidly moved 
across the rasp, or conversely the rasp across the scraper. 




Fiff. 25. 



Necrophorus (from Landois). r. The two rasps, 
figure, part of the rasp highly magnified. 



Left-hand 



These organs are situated in widely different positions. In the 
carrion-beetles (Necrophorus) two parallel rasps (r, fig. 25) stand 
on the dorsal surface of the fifth abdominal segment, each rasp'* 
consisting of 126 to 140 fine ribs. These ribs are scraped against 
the posterior margins of the elytra, a small portion of which pro- 
jects beyond the general outline. In many Crioceridae, and in 
Clythra 4-punctata (one of the Chrysomelidse), and in some Tene- 
brionidae, &c.,''^ the rasp is seated on the dorsal apex of the abdo- 
men, on the pygidium or pro-pygidium, and is scraped in the same 
manner by the elytra. In Heterocerus, which belongs to another 
family, the rasps are placed on the sides of the first abdominal 



7* Landois, 'Zeitschrift fur wiss. Zoolog.' B. xvii. 1867, s. 127. 

■^5 I am greatly indebted to Mr. G. R. Crotch for having sent me 
many prepared specimens of various beetles belonging to these three 
families and to others, as well as for valuable information. He be- 
lieves that the power of stridulation in the Clythra has not been pre- 
viously observed. I am also much indebted to Mr. E. W. Janson, 
for information and specimens. I may add that my son, Mr. P. Dar- 
win, finds that Dermestes murinus stridulates, but he searched in 
vain for the apparatus. Scolytus has lately been described by Dr. 
Chapman as a stridulator, in the 'Entomologist's Monthly Magazine,* 
vol. vi. p. 130. 



300 



THE DESCENT OF MAN. 



segment, and are scraped by ridges on the femora.'*' In certain 
Curcullonidse and Carabidae," the parts are completely reversed in 
position, for the rasps are seated on the inferior surface of the 
elytra, near their apices, or along their outer margins, and the 
edges of the abdominal segments serve as the scrapers. In Pelo- 
bius Hermann! (one of Dytiscidse or water-beetles) a strong ridge 
runs parallel and near to the sutural margin of the elytra, and is 
crossed by ribs, coarse in the middle part, but becoming gradually 
finer at both ends, especially at the upper end; when this insect is 
held under water or in the air a stridulating noise is produced 
by the extreme horny margin of the abdomen being scraped 
against the rasps. In a great number of long-horned beetles 
(Longicornia) the organs are situated quite otherwise, the rasp 
being on the meso-thorax, which is rubbed against the pro-thorax; 
Landois counted 238 very fine ribs on the rasp 
jf of Cerambyx heros. 

Many Lamellicorns have the power of stridu- 
lating, and the organs differ greatly in position. 
Some species stridulate very loudly, so that 
when Mr. F. Smith caught a Trox sabulosus, 
a gamekeeper, who stood by, thought he had 
caught a mouse; but I failed to discover the 
proper organs in this beetle. In Geotrupes and 
Typhosus a narrow ridge runs obliquely across 
(r. fig. 26) the coxa of each hind-leg (having in 
G. stercorarius 84 ribs), which is scraped by a 
specially projecting part of one of the abdominal 
segments. In the nearly allied Copris lunaris, 
an excessively narrow fine rasp runs along the 
sutural margin of the elytra, with another short 
rasp near the basal outer margin; but in some 
other Coprini the rasp is seated, according to 
Leconte,-^ on the dorsal surface of the abdomen. 
In Oryctes it is seated on the pro-pygidium; and, 
according to the same entomologist, in some 
other Dynastini, on the under surface of the elytra. Lastly, West- 




Fig. 26. Hind- 
leg of Geo- 
trupes stercor- 
arius (from 
Landois). 

r. Rasp. c. Coxa, 
f. Femur, t. 
Tibia tr. Tarsi. 



'6 Schiodte, translated in 'Annals and Mag. of Nat. Hist.' vol. xx. 
1867, p. 37. 

" Westring has described (Kroyer, 'Naturhist. Tidskrift,' B. ii. 1848- 
49, p. 334) the stridulating organs in these two, as well as in other 
families. In the Carabidae I have examined Elaphrus uliginosus and 
Blethisa multipunctata, sent to me by Mr. Crotch. In Blethisa the 
transverse ridges on the furrowed border of the abdominal segment 
do not, as far as I could judge, come into play in scraping the rasps 
on the elytra. 

78 1 am indebted to Mr, Walsh, of Illinois, for having sent me ex- 
tracts from Leconte's 'Introduction to Entomology,' pp. 101, 143. 



COLEOPTERA. 301 

ring states that in Omaloplia brunnea the rasp is placed on the pro- 
sternum, and the scraper on the meta-stei'num, the parts thus oc- 
cupying the under surface of the body, instead of the upper sur- 
face as in the Longicorns. 

We thus see that in the different coleopterous families the 
stridulating organs are wonderfully diversified in position, but not 
much in structure. Within the same family some species are pro- 
vided with these organs, and others are destitute of them. This 
diversity is intelligible, if we suppose that originally various bee- 
tles made a shuffling or hissing noise by the rubbing together of 
any hard and rough parts of their bodies, which happened to be in 
contact; and that from the noise thus produced being in some way 
useful, the rough surfaces were gradually developed into regular 
stridulating organs. Some beetles as they move, now produce, 
either intentionally or unintentionally, a shuffling noise, without 
possessing any proper organs for the purpose. Mr. Wallace in- 
forms me that the Euchirus longimanus (a Lamellicorn, with the 
anterior legs wonderfully elongated in the male) "makes, whilst 
"moving, a low hissing sound by the protrusion and contraction of 
"the abdomen; and when seized it produces a grating sound by 
"rubbing its hind-legs against the edges of the elytra." The hiss- 
ing sound is clearly due to a narrow rasp running along the sut- 
ural margin of each elytron; and I could likewise make the grat- 
ing sound by rubbing the shagreened surface of the femur against 
the granulated margin of the corresponding elytron; but I could 
not here detect any proper rasp; nor is it likely that I could have 
overlooked it in so large an insect. After examining Cychrus, and 
reading what Westring has written about this beetle, it seems very 
doubtful whether it possesses any true rasp, though it has the 
power of emitting a sound. 

From the analogy of the Orthoptera and Homoptera, I expected 
to find the stridulating organs in the Coleoptera differing accord- 
ing to sex; but Landois, who has carefully examined several 
species, observed no such difference; nor did Westring; nor did 
Mr. G. R. Crotch in preparing the many specimens which he had 
the kindness to send me. Any difference in these organs, if slight, 
would, however, be difficult to detect, on account of their great 
variability. Thus, in the first pair of specimens of Necrophorus 
humator and of Pelobius which I examined, the rasp was consider- 
ably larger in the male than in the female; but not so with suc- 
ceeding specimens. In Geotrupes stercorarius the rasp appeared 
to me thicker, opaquer, and more prominent in three males than 
in the same number of females; in order, therefore, to discover 
whether the sexes differed in their power of stridulating, my son, 
Mr. F. Darwin, collected fifty-seven living specimens, which he 
separated into two lots, according as they made a greater or lesser 
noise, when held in the same manner. He then examined all 



302 THE DESCENT OF MAN. 

these specimens, and found that the males were very nearly in the 
same proportion to the females in both the lots. Mr, F, Smith has 
kept alive numerous specimens of Monoynchus pseudacori (Cur- 
culionidse), and is convinced that both sexes stridulate, and ap- 
parently in an equal degree. 

Nevertheless, the power of stridulating is certainly a sexual char- 
acter in some few Coleoptera. Mr. Crotch discovered that the 
males alone of two species of Heliopathes (Tenebrionidse) possess 
stridulating organs. I examined five males of H. gibbus, and in all 
these there was a well-developed rasp, partially divided into two, 
on the dorsal surface of the terminal abdominal segment; whilst 
in the same number of females there was not even a rudiment of 
the rasp, the membrane of this segment being transparent, and 
much thinner than in the male. In H. cribratostriatus the male 
has a similar rasp, excepting that it is not partially divided into 
two portions, and the female is completely destitute of this or- 
gan; the male in addition has on the apical margins of the elytra, 
on each side of the suture, three or four short longitudinal ridges, 
which are crossed by extremely fine ribs, parallel to and resem- 
bling those on the abdominal rasp; whether these ridges serve as 
an independent rasp, or as a scraper for the abdominal rasp, I 
could not decide; the female exhibits no trace of this latter struc- 
ture. 

Again, in three species of the Lamellicorn ^enus Oryctes, we 
have a nearly parallel case. In the females of O. gryphus and 
nasicornis the ribs on the rasp of the pro-pygidium are less con- 
tinuous and less distinct than in the males; but the chief differ- 
ence is that the whole upper surface of this segment, when held 
in the proper light, is seen to be clothed with hairs, which are ab- 
sent or are represented by excessively fine down in the males. It 
should be noticed that in all Coleoptera the effective part of the 
rasp is destitute of hairs. In O. senegalensis the difference be- 
tween the sexes is more strongly marked, and this is best seen 
when the proper abdominal segment is cleaned and viewed as a 
transparent object. In the female the whole surface is covered 
■v\ith little separate crests, bearing spines; whilst in the male 
these crests in proceeding towards the apex, become more 
and more confluent, regular, and naked; so that three-fourths 
of the segment is covered with extremely fine parallel ribs, which 
are quite absent in the female. In the females, however, of all 
three species of Oryctes, a slight grating or stridulating sound is 
produced, when the abdomen of a softened specimen is pushed 
backwards and forwards. 

In the case of the Heliopathes and Oryctes there can hardly be a 
doubt that the males stridulate in order to call or to excite the 
females; but with most beetles the stridulation apparently serves 
both sexes as a mutual call. Beetles stridulate under various emo- 



COLEOPTERA. 303 

tions, in the same manner as birds use their voices for many pur- 
poses besides singing to their mates. The great Chiasognathus 
stridulates in anger or defiance; many species do the same from 
distress or fear, if held so that they cannot escape; by striking the 
hollow stems of trees in the Canary Islands, Messrs. Wollaston 
and Crotch were able to discover the presence of beetles belonging 
to the genus Acalles by their stridulation. Lastly, the male Ateu- 
chus stridulates to encourage the female in her work, and from 
distress when she is removed. '^^ Some naturalists believe that 
beetles make this noise to frighten away their enemies; but I can- 
not think that a quadruped or bird, able to devour a large beetle, 
would be frightened by so slight a sound. The belief that the 
stridulation serves as a sexual call is supported by the fact that 
death-ticks (Anobium tessellatum) are well known to answer each 
other's ticking, and, as I have myself observed, a tapping noise 
artificially made. Mr. Doubleday also informs me that he has 
sometimes observed a female ticking,^'' and in an hour or two after- 
wards has found her united with a male, and on one occasion 
surrounded by several males. Finally, it is probable that the 
two sexes of many kinds of beetles were at first enabled to find 
each other by the slight shufiling noise produced by the rubbing 
together of the adjoining hard parts of their bodies; and that as 
those males or females which made the greatest noise succeeded 
best in finding partners, rugosities on various parts of their bodies 
were gradually developed by means of sexual selection into true 
stridulating organs. 

79 M. P. de la Brulerie, as quoted in 'Journal of Travel,' A. Murray, 
vol. i. 1868, p. 135. 

80 According to Mr. Doubleday, "the noise is produced by the insect 
"raising itself on its legs as high as it can, and then striking its thorax 
"five or six times, in rapid succession, against the substance upon 
"which it is sitting." For references on this subject see Landois, 
'Zeitschrift fur wissen. Zoolog.' B. xvii. s. 131. Oliver says (as quoted 
by Kirby and Spence, 'Introduct.' vol. ii. p. 395) that the female of 
Pimelia striata produces a rather loud sound by striking her abdomen 
against any hard substance, "and that the male, obedient to this call, 
"soon attends her, and they pair." 



S04 THE DESCENT OF MAN. 



CHAPTER XL 

INSECTS, CONTINUED.— ORDER LEPIDOPTERA. 

(Butterflies and Moths.) 

Courtship of butterflies — Battles — Ticking- noise— Colors common to 
both sexes, or more brilliant in the males— Examples— Not due to the 
direct action of the conditions of life — Colors adapted for protec- 
tion—Colors of moths— Display— Perceptive powers of the Lepi- 
doptera — Variability — Causes of the difference in color between the 
males and females— Mimicry, female butterflies more brilliantly 
colored than the males— Bright colors of caterpillars— Summary and 
concluding- remarks on the secondary sexual characters of insects 
— Birds and insects compared. 

In this great Order the most interesting points for us are the 
differences in color between the sexes of the same species, and be- 
tween the distinct species of the same genus. Nearly the whole 
of the following chapter will he devoted to this subject; but I will 
first make a few remarks on one or two other points. Several 
males may often be seen pursuing and crowding round the same 
female. Their courtship appears to be a prolonged affair, for I 
have frequently watched one or more males pirouetting round a 
female until I was tired, without seeing the end of the courtship. 
Mr. A. G. Butler also informs me that he has several times watched 
a male courting a female for a full quarter of an hour; but she 
pertinaciously refused him, and at last settled on the ground and 
closed her wings, so as to escape from his addresses. 

Although butterflies are weak and fragile creatures, they are 
pugnacious, and an Emperor butterfly^ has been captured with the 
tips of its wings broken from a conflict with another male. Mr. 
Collingwood, in speaking of the frequent battles between the but- 
terflies of Borneo, says, "They whirl round each other with the 
"greatest rapidity, and appear to be incited by the greatest fe- 
"rocity." 

The Ageronia feronia makes a noise like that produced by a 

1 Apatura Iris: 'The Entomologist's Weekly Intelligence,' 1859, p. 139. 
For the Bornean Butterflies, see C. Collingrwood, 'Rambles of a 

Naturalist,' 186S, p. 183. 



BUTTERFLIES AND MOTHS. 305 

toothed wheel passing under a spring catch, and which can be 
heard at the distance of several yards: I noticed this sound at 
Rio de Janeiro, only when two of these butterflies were chasing 
each other in an irregular course, so that it is prohahly made dur- 
ing the courtship of the sexes.- 

Some moths also produce sounds; for instance, the males of 
Thecophora fovea. On two occasions Mr. F. Buchanan White^ 
heard a sharp quick noise made by the male of Hylophila pras- 
inana, and which he believes to be produced, as in Cicada, by an 
elastic membrane, furnished with a muscle. He quotes, also, 
Guenee, that Setina produces a sound like the ticking of a watch, 
apparently by the aid of "two large tympaniform vesicles, sit- 
"uated in the pectoral region;" and these "are much more 
"developed in the male than in the female." Hence the sound- 
producing organs in the Lepidoptera appear to stand in some re- 
lation with the sexual functions. I have not alluded to the well- 
known noise made by the Death's Head Sphinx, for it is generally 
heard soon after the moth has emerged from its cocoon. 

Girard has always observed that the musky odor, which is 
emitted by two species of Sphinx moths, is peculiar to the males ;^ 
and in the higher classes we shall meet with many instances of 
the males alone being odoriferous. 

Every one must have admired the extreme beauty of many but- 
terflies and of some moths; and it may be asked, are their colors 
and diversified patterns the result of the direct action of the 
physical conditions to which these insects have been exposed, 
without any benefit being thus derived? Or have successive va- 
riations been accumulated and determined as a protection, or for 
some unknown purpose, or that one sex may be attractive to the 
other? And, again, what is the meaning of the colors being 
widely different in the males and females of certain species, and 
alike in the two sexes of other species of the same genus? Before 
attempting to answer these questions a body of facts must be 
given. 

With our beautiful English butterflies, the admiral, peacock, 
and painted lady (Vanessae), as well as many others, the sexes are 
alike. This is also the case with the magnificent Heliconidse, ana 
most of the Danaidae in the tropics. But in certain other tropical 
groups, and in some of our English butterflies, as the purple em- 

8 See my 'Journal of Researches,' 1845, p. 33. Mr. Doubleda^^ has de- 
tected ('Proc. Ent. Soc' March 3rd, 1845, p. 123) a peculiar membranous 
sac at the base of the front wing-s, which is probably connected with 
the production of the sound. For the case of Thecophora, see 'Zoo- 
logical Record,' 1869, p. 401. For Mr, Buchanan White's observations, 
'The Scottish Naturalist,' July 1872, p. 214. 

3 'The Scottish Naturalist,' July 1872, p, 213. 

* 'Zoological Record,' 1869, p, 347. 
21 



306 THE DESCENT OP MAN. 

peror, orange-tip, &c. (Apartura Iris and Anttiocharis carda- 
mines), the sexes differ either greatly or slightly in color. No lan- 
guage suffices to describe the splendor of the males of some tropi- 
cal species. Even within the same genus we often find species 
presenting extraordinary differences between the sexes, whilst 
others have their sexes closely alike. Thus in the South American 
genus Epicalia, Mr. Bates, to whom I am indebted for most of the 
following facts, and for looking over this whole discussion, in- 
forms me that he knows twelve species, the two sexes of which 
haunt the same stations (and this is not always the case with 
butterflies), and which, therefore, cannot have been differently af- 
fected by external conditions.^ In nine of these twelve species the 
males rank amongst the most brilliant of all butterflies, and differ 
so greatly from the comparatively plain females that they were 
formerly placed in distinct genera. The females of these nine 
species resemble each other in their general type of coloration; 
and they likewise resemble both sexes of the species in several 
allied genera, found in various parts of the world. Hence we 
may infer that these nine species, and probably all the others of 
the genus, are descended from an ancestral form which was col- 
ored in nearly the same manner. In the tenth species the female 
still retains the same general coloring, but the male resembles 
her, so that he is colored in a much less gaudy and contrasted 
manner than the males of the previous species. In the eleventh 
and twelfth species, the females depart from the usual type, for 
they are gaily decorated almost like the males, but in a somewhat 
less degree. Hence in these two latter species the bright colors 
of the males seem to have been transferred to the females; whilst 
in the tenth species the male has either retained or recovered the 
plain colors of the female, as well as of the parent-form of the 
genus. The sexes in these three cases have thus been rendered 
nearly alike, though in an opposite manner. In the allied genus 
Eubagis, both sexes of some of the species are plain-colored and 
nearly alike; whilst with the greater number the males are deco- 
rated with beautiful metallic tints in a diversifled manner, and 
differ much from their females. The females throughout the 
genus retain the same general style of coloring, so that they re- 
semble one another much more closely than they resemble their 
own males. 

In the genus Papilio, all the species of the ^neas group are 
remarkable for their conspicuous and strongly contrasted colors, 
and they illustrate the frequent tendency to gradation in the 
amount of difference between the sexes. In a few species, for 

5 See also Mr. Bates's paper in 'Proc. Ent. Soc. of Philadelphia,' 
1865, p. 206. Also Mr. Wallace on the same subject, in regard to 
Diadema, in 'Transact. Entomolog. Soc. of London,' 1869, p. 278. 



BUTTERFLIES AND MOTHS. 307 

Instance in P. ascanius, the males and females are alike; in uthers 
the males are either a little brighter, or very much more superb 
than the females. The genus Junonia, allied to our Vanessae, 
offers a nearly parallel case, for although the sexes of most of 
the species resemble each other, and are destitute of rich colors, 
j^et in certain species, as in J. cenone, the male is rather more 
bright-colored than the female, and in a few (for instance J. 
andremiaja) the male is so different from the female that he 
might be mistaken for an entirely distinct species. 

Another striking case was pointed out to me in the British 
Museum by Mr. A. Butler, namely, one of the tropical American 
Thecl^, in which both sexes are nearly alike and wonderfully 
splendid; in another species the male is colored in a similarly 
gorgeous manner, whilst the whole upper surface of the female 
is of a dull uniform brown. Our common little English blue 
butterflies of the genus Lycsena illustrate the various differences 
in color between the sexes, almost as well, though not in so 
striking a manner, as the above exotic genera. In Lyc^na 
agestis both sexes have wings of a brown color, bordered with 
small ocellated orange spots, and are thus alike, in L. cegon 
the wings of the male are of a fine blue, bordered with black; 
whilst those of the female are brown, with a similar border, 
closely resembling the wings of L. agestis. Lastly, in L. arion 
both sexes are of a blue color and are very like, though in the 
female the edges of the wings are rather duskier, with the black 
spots plainer; and in a bright blue Indian species both sexes are 
still more alike. 

I have given the foregoing details in order to show, in the first 
place, that when the sexes of butterflies differ, the male as a 
general rule is the more beautiful, and departs more from the 
usual type of coloring of the group to which the species be- 
longs. Hence in most groups the females of the several species 
resemble each other much more closely than do the males. In 
some cases, however, to which I shall hereafter allude, the females 
are colored more splendidly than the males. In the second place, 
these details have been given to bring clearly before the mind 
that within the same genus, the two sexes frequently present 
every gradation from no difference in color, to so great a differ- 
ence that it was long before the two were placed by entomologists 
in the same genus. In the third place, we have seen that when 
the sexes nearly resemble each other, this appears due either 
to the male having transferred his colors to the female, or to the 
male having retained, or perhaps recovered, the primordial col- 
ors of the group. It also deserves notice that in those groups in 
which the sexes differ, the females usually somewhat resemble 
the males, so that when the males are beautiful to an extraor- 
dinary degree, the females almost invariably exhibit some degree 



SOS THE DESCENT OP MAN. 

of beauty. From the many cases of gradation in the amount of 
difference between the sexes, and from the prevalence of the same 
general type of coloration throughout the whole of the same 
group, we may conclude that the causes have generally been the 
same which have determined the brilliant coloring of the 
males alone of some species, and of both sexes of other species. 

As so many gorgeous butterflies inhabit the tropics, it has 
often been supposed that they owe their colors to the great heat 
and moisture of these zones; but Mr. Bates^ has shown by the 
comparison of various closely-allied groups of insects from the 
temperate and tropical regions, that this view cannot be main- 
tained; and the evidence becomes conclusive when brilliantly- 
colored males and plain-colored females of the same species 
inhabit the same district, feed on the same food, and follow ex- 
actly the same habits of life. Even when the sexes resemble 
each other, we can hardly believe that their brilliant and beau- 
tifully-arranged colors are the purposeless result of the nature of 
the tissues and of the action of the surrounding conditions. 

With animals of all kinds, whenever color has been modified 
for some special purpose, this has been, as far as we can judge, 
either for direct or indirect protection, or as an attraction be- 
tween the sexes. With many species of butterflies the upper sur- 
faces of the wings are obscure; and this in all probability leads 
to their escaping observation and danger. But butterflies would 
be particularly liable to be attacked by their enemies when at 
rest; and most kinds whilst resting raise their wings vertically 
over their backs, so that the lower surface alone is exi^osed to 
view. Hence it is this side which is often colored so as to imitate 
the objects on which these insects commonly rest. Dr. Rossler, 
I believe, first noticed the similarity of the closed wings of cer- 
tain Vanessse and other butterflies to the bark of trees. Many 
analogous and striking facts could be given. The most interesting 
one is that recorded by Mr. Wallace^ of a common Indian and 
Sumatran butterfly (Kallima), which disappears like magic when 
it settles on a bush; for it hides its head and antennae between its 
closed wings, which, in form, color and veining, cannot be dis- 
tinguished from a withered leaf with its footstalk. In some other 
cases the lower surfaces of the wings are brilliantly colored, and 
yet are protective; thus in Thecla rubi the wings when closed 
are of an emerald green, and resemble the young leaves of the 
bramble, on which in spring this butterfly may often be seen 
seated. It is also remarkable that in very many species in which 

6 'The Naturalist on the Amazons,' vol. i. 1863, p. 19. 

' See the interesting article in the 'Westminster Review,' July 1867, 
p. 10. A woodcut of the Kallima is given by Mr. Wallace in 'Hard- 
Wicke's Science Gossip,' Sept. 1867, p. 196. 



BUTTERFLIES AND MOTHS. 309 

the sexes differ greatly in color on their upper surface, the lower 
surface is closely similar or identical in both sexes, and serves 
as a protection.^ 

Although the obscure tints both of the upper and under 
sides of many butterflies no doubt serve to conceal them, yet we 
cannot extend this view to the brilliant and conspicuous colors 
on the upper surface of such species as our admiral and peacock 
Vanessae, our white cabbage-butterflies (Pieris), or the great 
swallow-tail Papilio which haunts the open fens — for these but- 
terflies are thus rendered visible to every living creature. In 
these species both sexes are alike; but in the common brim- 
stone butterfly (Gonepteryx rhamni), the male is of an intense 
yellow, whilst the female is much paler; and in the orange-tip 
(Anthocharis cardamines) the males alone have their v/ings tipped 
with bright orange. Both the males and females in these cases 
are conspicuous, and it is not credible that their difference in 
color should stand in any relation to ordinary protection. Prof. 
Weismann remarks,^ that the female of one of the Lycsense ex- 
pands her brown wings when she settles on the ground, and is 
then almost invisible; the male, on the other hand, as if aware of 
the danger incurred from the bright blue of the upper surface of 
his wings, rests with them closed; and this shows that the blue 
color cannot be in any way protective. Nevertheless, it is probable 
that conspicuous colors are indirectly beneficial to many species, 
as a warning that they are unpalatable. For in certain other 
cases, beauty has been gained through the imitation of other 
beautiful species, which inhabit the same district and enjoy an 
immunity from attack by being in some way offensive to their 
enemies; but then we have to account for the beauty of the 
imitated species. 

As Mr. Walsh has remarked to me, the females of our orange- 
tip butterfly, above referred to, and of an American species 
(Anth. genutia) probably show us the primordial colors of the 
parent-species of the genus; for both sexes of four or five 
widely-distributed species are colored in nearly the same manner. 
As in several previous cases, we may here infer that it is the 
males of Anth. cardamines and genutia which have departed 
from the usual type of the genus. In the Anth. sara from Cali- 
fornia, the orange-tips to the wings have been partially de- 
veloped in the female; but they are paler than in the male, and 
slightly different in some other respects. In an allied Indian 
form, the Iphias glaucippe, the orange-tips are fully developed in 
both sexes. In this Iphias, as pointed out to me by Mr. A. Butler, 
the under surface of the wings marvelously resembles a pale- 



8 Mr. G. Fraser, in 'Nature,' April 1871, p. 489. 

» 'Einfluss der Isolirung auf die Artbildung-,' 1872, p. 58. 



310 THE DESCENT OF MAN. 

colored leaf; and in our English orange-tip, tlie under surface 
vesembles the flower-head of the wild parsley, on which the 
butterfly often rests at night.^° The same reason which compels 
us to believe that the lower surfaces have here been colored for 
the sake of protection, leads us to deny that the wings have 
been tipped with bright orange for the same purpose, especially 
when this character is confined to the males. 

Most Moths rest motionless during the whole or greater part 
of the day with their wings depressed; and the whole upper 
surface is often shaded and colored in an admirable manner, as 
Mr. Wallace has remarked, for escaping detection. The front- 
wings of the Bombycidse and Noctuidse,^^ when at rest, generally 
overlap and conceal the hind-wings; so that the latter might be 
brightly colored without much risk; and they are in fact often 
thus colored. During flight, moths would often be able to escape 
from their enemies; nevertheless, as the hind-wings are then 
fully exposed to view, their bright colors must generally have 
been acquired at some little risk. But the following fact shows 
how cautious we ought to be in drawing conclusions on this head. 
The common Yellow Under-wings (Triphsena) often fly about 
during the day or early evening, and are then conspicuous from 
the color of their hind-wings. It would naturally be thought 
that this would be a source of danger; but Mr. J. Jenner Weir 
believes that it actually serves them as a means of escape, for 
birds strike at these brightly colored and fragile surfaces, in- 
stead of at the body. For instance, Mr. Weir turned into his 
aviary a vigorous specimen of Triphasna pronuba, which was in- 
stantly pursued by a robin; but the bird's attention being caught 
by the colored wings, the moth was not captured until after 
about fifty attempts, and small portions of the wings were re- 
peatedly broken off. He tried the same experiment, in the open 
air, with a swallow and T. fimbria; but the large size of this 
moth probably interfered with its capture.^^ We are thus remind- 
ed of a statement made by Mr. Wallace,^^ namely, that in the 
Brazilian forests and Malayan islands, many common and highly- 
decorated butterflies are weak flyers, though furnished with a 
broad expanse of wing; and they "are often captured with pierced 
"and broken wings, as if they had been seized by birds, from 
"which they had escaped: if the wings had been much smaller 

10 See the interesting observations by Mr. T. W. Wood, 'The Student,* 
Sept. 1868, p. 81. 

11 Mr. Wallace in 'Hardwicke's Science Gossip,' Sept. 1867, p. 193. 

12 See also, on this subject, Mr. Weir's paper in 'Transact, Ent. Soc' 
1869, p. 23. 

13 'Westminster Review,' July 1867, p. 16. 



BUTTERFLIES AND MOTHS. 311 

"in proportion to the body, it seerns probable that the insect 
"would more frequently have been struck cr pierced in a vital 
"part, and thus the increased espanse of the wings may have been 
"indirectly beneficial." 

Display. — The bright colors of many butterflies and of some 
moths are specially arranged for display, so that they may be 
readily seen. During the night colors are not visible, and 
there can be no doubt that the nocturnal moths, taken as a 
body, are much less gaily decorated than butterflies, all of 
which are diurnal in their habits. But the moths of certain 
families, such as the Zygaenidse, several Sphingidae, Uraniidse, 
some Arctiidag and SaturniidiB, fly about during the day or 
early evening, and many of these are extremely beautiful, being 
far brighter colored than the strictly nocturnal kinds. A few 
exceptional cases, however, of bright-colored nocturnal species 
have been recorded." 

There is evidence of another kind in regard to display. But- 
terflies, as before remarked, elevate their wings when at rest, 
but whilst basking in the sunshine often alternately raise and 
depress them, thus exposing both surfaces to full view; and al- 
though the lower surface is often colored in an obscure manner 
as a protection, yet in many species it is as highly decorated 
as the upper surface, and sometimes in a very different manner. 
In some tropical species the lower surface is even more brilliantly 
colored than the upper.^^ In the English fritillaries (Argynnis) 
the lower surface alone is ornamented with shining silver. Never- 
theless, as a general rule, the upper surface, which is probably 
more fully exposed, is colored more brightly and diversely than 
the lower. Hence the lower surface generally affords to en- 
tomologists the more useful character for detecting the affinities 
of the various species. Fritz Miiller informs me that three 
species of Castnia are found near his house in S. Brazil: of two 
of them the hind-wings are obscure, and are always covered by 
the front-wings when these butterflies are at rest; but the third 
species has black hind-wings, beautifully spotted with red and 
white, and these are fully expanded and displayed whenever the 
butterfly rests. Other Ruch cases could be added. 

If we now turn to the enormous group of moths, which, as 

14 For instance, Lithosia; but Prof. Westwood ('Modem Class, of 
Insects,' vol. ii. p. 390) seems surprised at this case. On the relative 
colors of diurnal and nocturnal Lepidoptera, see ibid. pp. 333 and 3S2; 
also Harris, 'Treatise on the Insects of New England,' 1842, p. 315. 

^ Such differences between the upper and lower surfaces of the wing-s 
of several species of Papilio, may be seen in the beautiful plates to 
Mr. Wallace's 'Memoir on the Papilionidae of the Malayan Region,' 
in 'Transact. Linn. Soc,' vol. xxv. part i. 1865. 



312 THE DESCENT OF MAN. 

I hear from Mr. Stainton, do not habitually expbse the under 
surface of their wings to full view, we find this side very rarely 
colored with a brightness greater than, or even equal to, that 
of the upper side. Some exceptions to the rule, either real or 
apparent, must be noticed, as the case of Hypopyra/'' Mr. Trimen 
informs me that in Guenee's great work, three moths are figured, 
in which the under surface is much the more brilliant. For 
instance, in the Australian Gastrophora the upper surface of the 
fore-wing is pale grayish-ochreous, while the lower surface is 
magnificently ornamented by an ocellus of cobalt-blue, placed 
in the midst of a black mark, surrounded by orange-yellow, and 
this by bluish-white. But the habits of these three moths are 
unknown; so that no explanation can be given of their unusual 
style of coloring. Mr. Trimen also informs me that the lower 
surface of the wings in certain other Geometrse" and quadrifid 
Noctuas are either more variegated or more brightly-colored than 
the upper surface; but novae of these species have the habit of 
"holding their wings quite erect over their backs, retaining them 
"in this position for a considerable time," and thus exposing the 
under surface to view. Other species, when settled on the ground 
or herbage, now and then suddenly and slightly lift up their 
wings. Hence the lower surface of the wings being brighter 
than the upper surface in certain moths is not so anomalous as it 
at first appears. The Saturniidse include some of the most beau- 
tiful of all moths, their wings being decorated, as in our British 
Emperor moth, with fine ocelli; and Mr. T. W. Wood^® observes 
that they resemble butterflies in some of their movements; "for 
"instance, in the gentle waving up and down of the wings as if 
"for display, which is more characteristic of diurnal than of 
"nocturnal Lepidoptera." 

It is a singular fact that no British moths which are brilliantly 
colored, and, as far as I can discover, hardly any foreign species, 
differ much in color according to sex; though this is the case with 
many brilliant butterflies. The male, however, of one American 
moth, the Saturnia lo, is described as having its fore-wings deep 
yellow, curiously marked with purplish-red spols; whilst the 
wings of the female are purple-brown, marked with gray lines." 
The British moths which differ sexually in color are all brown, 
or of various dull yellow tints, or nearly white. In several 
species the males are much darker than the females,^" and these 

16 See Mr. Wormald on this moth: 'Proc. Ent. Soc' March 2nd, 1868. 

" See also an account of the S. American g-enus Erateina (one of the 
Geometrae) in 'Transact. Ent. Soc' new series, vol. v. pi. xv. and xvi. 

18 'Proc. Ent. Soc. of London,' July 6, 1868, p. xxvii. 

i» Harris, 'Treatise,' «S;c., edited by Flint, 1862, p. 395. 

20 por instance, I observe in my son's cabinet that the males are 
darker than the females in the Lasiocampa quercus, Odonestis pota- 



BUTTERFLIES AND MOTHS. 313 

belong to groups which generally fly about during the afternoon. 
On the other hand, in many genera, as Mr. Stainton informs me, 
the males have the hind-wings whiter than those of the female — 
of which fact Agrotis exclamationis offers a good instance. In 
the Ghost Moth (Hepiaius humuli) the difference is more strongly 
marked; the males being white, and the females yellow with 
darker markings.^^ It is probable that in these cases the males 
are thus rendered more conspicuous, and more easily seen by 
the females whilst flying about in the dusk. 

From the several foregoing facts it is impossible to admit that 
the brilliant colors of butterflies, and of some few moths, have 
commonly been acquired for the sake of protection. We have 
seen that their colors and elegant patterns are arranged and ex- 
hibited as if for display. Hence I am led to believe that the 
females prefer or are most excited by the more brilliant males; 
for on any other supposition the males would, as far as we can 
see, be ornamented to no purpose. We know that ants and 
certain Lamellicorn beetles are capable of feeling an attachment 
for each other, and that ants recognize their fellows after an 
interval of several months. Hence there is no abstract im- 
probability in the Lepidoptera, which probably stand nearly or 
quite as high in the scale as these insects, having sufficient mental 
capacity to admire bright colors. They certainly discover flowers 
by color. The Humming-bird Sphinx may often be seen to 
swoop down from a distance on a bunch of flowers in the midst 
of green foliage; and I have been assured by two persons 
abroad, that these moths repeatedly visit flowers painted on the 
walls of a room, and vainly endeavor to insert their proboscis into 
them. Fritz Miiller informs me that several kinds of butterflies 



toria, Hypogymn dispur, Dasychira pudibunda, and Cycnia mendica. 
In this latter species the difEerence in color between the two sexes is 
strong-ly marked; and Mr. Wallace informs me that we here have, 
as he believes, an instance of protective mimicry confined to one sex, 
as will hereafter be more fully explained. The white female of the 
Cycnia resembles the very common Spilosoma menthrasti, both sexes 
of which are white; and Mr. Stainton observed that this latter moth 
was rejected with utter disgust by a whole brood of young turkeys, 
which were fond of eating other moths; so that if the Cycnia was 
commonly mistaken by British birds for the Spilosoma, it would 
escape being devoured, and its white deceptive color would thus be 
highly beneficial. 

21 It is remarkable, that in the Shetland Islands the male of this 
moth, instead of differing widely from the female, frequently re- 
sembles her closely in color (see Mr. MacLachlan, 'Transact. Ent. Soc' 
vol. ii. 1866, p. 459). Mr. G. Eraser suggests ('Nature,' April 1871, p. 
489) that at the season of the year when the ghost-moth appears in 
these northern islands, the whiteness of the males would not be needed 
to render them visible to the females in the twilight night. 



314 THE DESCENT OP MAN. 

in S. Brazil, show an unmistakable preference for certain colors 
over others: he observed that they very often visited the brill- 
iant red flowers of five or six genera of plants, but never the 
white or yellow flowering species of the same and other genera, 
growing in the same garden; and I have received other accounts 
to the same effect. As I hear from Mr. Doubleday, the common 
white butterfly often flies down to a bit of paper on the ground, 
no doubt mistaking it for one of its own species. Mr. Colling- 
wood-2 in speaking of the difficulty in collecting certain butter- 
flies in the Malay Archipelago, states that "a dead specimen pinned 
"upon a conspicuous twig will often arrest an insect of the 
"same species in its headlong flight, and bring it down within 
"easy reach of the net, especially if it be of the opposite sex." 

The courtship of butterflies is, as before remarked, a pro- 
longed affair. The males sometimes fight together in rivalry; and 
many may be seen pursuing or crowding round the same female. 
Unless, then, the females prefer one male to another, the pairing 
must be left to mere chance, and this does not appear probable. 
If, on the other hand, the females habitually, or even occasionally, 
prefer the more beautiful males, the colors of the latter will 
have been rendered brighter by degrees, and will have been 
transmitted to both sexes or to one sex, according to the law 
of inheritance which has prevailed. The process of sexual selec- 
tion will have been much facilitated, if the conclusion can be 
trusted, arrived at from various kinds of evidence in the supple- 
ment to the ninth chapter; namely, that the males of many 
Lepidoptera, at least in the imago state, greatly exceed the 
females in number. 

Some facts, however, are opposed to the belief that female 
butterflies prefer the more beautiful males; thus, as I have 
been assured by several collectors, fresh females may frequently 
be seen paired with battered, faded, or dingy males; but this is 
a circumstance which could hardly fail often to follow from the 
males -emerging from their cocoons earlier than the females. 
With moths of the family of the Bombycidse, the sexes pair im- 
mediately after assuming the imago state; for they cannot feed, 
owing to the rudimentary condition of their mouths. The females, 
as several entomologists have remarked to me, lie in an almost 
torpid state, and appear not to evince the least choice in regard 
to their partners. This is the case with the common silk-motli 
(B. mori), as I have been told by some continental and English 
breeders. Dr. Wallace, who has had great experience in breeding 
Bombyx cynthia, is convinced that the females evince no choice 
or preference. He has kept above 300 of these moths together, 
and has often found the most vigorous females mated with 

-2 'Rambles of a Naturalist in the Chinese Seas/ 1868, p. 182. 



BUTTERFLIES AND MOTHS. 315 

Stunted males. The reverse appears to occur seldom; for, as he 
believes, the more vigorous males pass over the weakly females, 
and are attracted by those endowed with most vitality. Neverthe- 
less, the Bombycidse, though obscurely-colored, are often beauti- 
ful to our eyes from their elegant and mottled shades. 

I have as yet only referred to the species in which the males 
are brighter colored than the females, and I have attributed 
their beauty to the females for many generations having chosen 
and paired with the more attractive males. But converse cases 
occur, though rarely, in which the females are more brilliant 
than the males; and here, as I believe, the males have selected 
the more beautiful females, and have thus slowly added to their 
beauty. We do not know why in various classes of animals the 
males of some few species have selected the more beautiful fe- 
males instead of having gladly accepted any female, as seems to 
be the general rule in the animal kingdom; but if, contrary to 
what generally occurs with the Lepidoptera, the females were 
much more numerous than the males, the latter would be likely 
to pick out the more beautiful females. Mr. Butler showed me 
several species of Callidryas in the British Museum, in some of 
which the females equalled, and in others greatly surpassed the 
males in beauty; for the females alone have the borders of their 
wings suffused with crimson and orange, and spotted with black. 
The plainer males of these species closely resemble each other, 
showing that here the females have been modified; whereas 
in those cases, where the males are the more ornate, it is these 
which have been modified, the females remaining closely alike. 

In England we have some analogous cases, though not so 
marked. The females alone of two species of Thecla have a 
bright-purple or orange patch on their fore-vnngs. In Hip- 
parchia the sexes do not differ much; but it is the female of 
H. janira which has a conspicuous light-brown patch on her 
wings; and the females of some of the other species are brighter 
colored than their males. Again, the females of Colias edusa and 
hyale have "orange or yellow spots on the black marginal border, 
"represented in the males only by thin streaks;" and in Pieris 
it is the females which "are ornamented with black spots on the 
"fore-wings, and these are only partially present in the males." 
Now the males of many butterflies are known to support the 
females during their marriage flight; but in the species just 
named it is the females which support the males; so that the 
part which the two sexes play is reversed, as is their relative 
beauty. Throughout the animal kingdom the males commonly 
take the more active share in wooing, and their beauty seems 
to have been increased by the females having accepted the more 
attractive individuals; but with these butterflies, the females 
take the more active part in the final marriage ceremony, so 



316 THE DESCENT OF MAN. 

that we may suppose that they likewise do so in the wooing; and 
in this case we can understand hew it is that they have heen 
rendered the more beautiful. Mr. Meldola, from whom the fore- 
going statements have been taken, says in conclusion: "Though 
"I am not convinced of the action of sexual selection in produc- 
"ing the colors of insects, it cannot be denied that these facts are 
"strikingly corroborative of Mr. Darwin's views." 



"23 



As sexual selection primarily depends on variability, a few 
words must be added on this subject. In respect to color there 
is no difficulty, for any number of highly variable Lepidoptera 
could be named. One good instance will suffice. Mr. Bates 
showed me a whole series of specimens of Papilio sesostris and 
P. childrense; in the latter the males varied much in the extent 
of the beautifully enamelled green patch on the fore-wings, and 
in the size of the white mark, and of the splendid crimson stripe 
on the hind-wings; so that there was a great contrast amongst 
the males between the most and the least gaudy. The male of 
Papilio sesostris is much less beautiful than of P. childrense; 
and it likewise varies a little in the size of the green patch on the 
fore-wings, and in the occasional appearance of the small crimson 
stripe on the hind-wings, borrowed, as it would seem, from its 
own female; for the females of this and of many other species 
in the ^neas group possess this crimson stripe. Hence between 
the brightest specimens of P. sesostris and the dullest of P. chil- 
drense, there was but a small interval; and it was evident that as 
far as mere variability is concerned, there would be no difficulty 
in permanently increasing the beauty of either species by means 
of selection. The variability is here almost confined to the male 
sex; but Mr. Wallace and Mr. Bates have shown-* that the females 
of some species are extremely variable, the males being nearly 
constant. In a future chapter I shall have occasion to show that 
the beautiful eye-like spots, or ocelli, found on the wings of 
many Lepidoptera, are eminently variable. I may here add that 
these ocelli offer a difficulty on the theory of sexual selection; 
for though appearing to us so ornamental, they are never pres- 
ent in one sex and absent in the other, nor do they ever differ 



23 'Nature,' April 27th, 1871, p. 508. Mr. Meldola quotes Donzel, in 
'Soc. Ent. de France,' 1837, p. 77, on the flight of butterflies whilst 
pairing-. See also Mr. G. Fraser, in 'Nature,' April 20th, 1871, p. 489, on 
the sexual differences of several British butterflies. 

24 Wallace on the Papilionidae of the Malayan Region, in 'Transact. 
Linn. Soc' vol. xxv. 1865, pp. 8, 36. A striking case of a rare variety, 
strictly intermediate between two other well-marked female varieties, 
is given by Mr. "Wallace. See also Mr. Bates, in 'Proc. Entomologr. 
Soc' Nov. 19th, 1866, p. xl. 



BUTTERFLIES AND MOTHS. 317 

much in the two sexes.-" This fact is at present inexplicable; 
but if it should hereafter be found that the formation of an ocellus 
is due to some change in the tissues of the wings, for instance, 
occurring at a very early period of development, we might expect, 
from what we know of the laws of inheritance, that it would be 
transmitted to both sexes, though arising and perfected in one 
sex alone. 

On the whole, though many serious objections may be urged, 
it seems probable that most of the brilliantly colored species of 
Lepidoptera owe their colors to sexual selection, excepting in 
certain cases, presently to be mentioned, in which conspicuous 
colors have been gained through mimicry as a protection. From 
the ardor of the male throughout the animal kingdom, he is 
generally willing to accept any female; and it is the female which 
usually exerts a choice. Hence, if sexual selection has been 
efficient with the Lepidoptera, the male, when the sexes differ, 
ought to be the more brilliantly colored, and this undoubtedly is 
the case. When both sexes are brilliantly colored and resemble 
each other, the characters acquired by the males appear to have 
been transmitted to both. We are led to this conclusion by cases, 
even within the same genus, of gradation from an extraordinary 
amount of difference to identity in color between the two sexes. 

But it may be asked whether the differences in color between 
the sexes may not be accounted for by other means besides 
sexual selection. Thus the males and females of the same species 
of butterfxy are in several cases known^^ to inhabit different sta- 
tions, the former commonly basking in the sunshine, the latter 
haunting gloomy forests. It is therefore possible that different 
conditions of life may have acted directly on the two sexes; but 
this is not probable," as in the adult state they are exposed to 
different conditions during a very short period; and the larvae 
of both are exposed to the same conditions. Mr. Wallace be- 
lieves that the difference between the sexes is due not so much 
to the males having been modified, as to the females having in all 
or almost all cases acquired dull colors for the sake of protection. 
It seems to me, on the contrary, far more probable that it is the 
males which have been chiefly modified through sexual selec- 
tion, the females having been comparatively little changed. 
We can thus understand how it is that the females of allied 
species generally resemble one another so much more closely 

25 Mr. Bates was so kind as to lay this subject before the Entomo- 
logical Society, and I have received answers to this effect from sev- 
eral entomologists. 

28 H. W. Bates, 'The Naturalist on the Amazons,' vol. ii. 1863, p. 228. 
A. R. Wallace, in 'Transact. Linn. SoC vol. xxv. 1865, p. 10. 

27 On this whole subject see 'The Variation of Animals and Plants 
under Domestication,' 1868, vol. ii. chap, xxiii. 



313 THE DESCENT OF MAN. 

than do the males. They thus show us approximately the pri- 
mordial coloring of the parent-species of the group to which they 
belong. They have, however, almost always been somewhat modi- 
fied by the transfer to them of some of the successive variations, 
through the accumulation of which the males were rendered beau- 
tiful. But I do not wish to deny that the females alone of some 
species may have been specially modified for protection. In most 
cases the males and females of distinct species will have been 
exposed during their prolonged larval state to different conditions, 
and may have been thus affected; though with the males any 
slight change of color thus caused will generally have been 
masked by the brilliant tints gained through sexual selection. 
When we treat of Birds, I shall have to discuss the whole question, 
as to how far the differences in color between the sexes are due 
to the males having been modified through sexual selection for 
ornamental purposes, or to the females having been modified 
through natural selection for the sake of protection, so that I will 
here say but little on the subject. 

In all the cases in which the more common form of equal 
inheritance by both sexes has prevailed, the selection of bright- 
colored males would tend to make the females bright-colored; 
and the selection of dull-colored females would tend to make 
the males dull. If both processes were carried on simultaneously, 
they would tend to counteract each other; and the final result 
would depend on whether a greater number of females from 
being well protected by obscure colors, or a greater number of 
males by being brightly-colored and thus finding partners, suc- 
ceeded in leaving more numerous offspring. 

In order to account for the frequent transmission of characters 
to one sex alone, Mr. Wallace expresses his belief that the more 
common form of equal inheritance by both sexes can be changed 
through natural selection into inheritance by one sex alone, but 
in favor of this view I can discover no evidence. We know from 
what occurs under domestication that new characters often ap- 
pear, which from the first are transmitted to one sex alone; and 
by the selection of such variations there v/ould not be the slight- 
est difficulty in giving bright colors to the males alone, and at 
the same time or subsequently, dull colors to the females alone. 
In this manner the females of some butterflies and moths have, it 
is probable, been rendered inconspicuous for the sake of pro- 
tection, and widely different from their males. 

I am, however, unwilling without distinct evidence to admit 
that two complex processes of selection, each requiring the 
transference of new characters to one sex alone, have been carried 
on with a multitude of species, — that the males have been rendered 
more brilliant by beating their rivals, and the females more dull- 
colored by having escaped from their enemies. The male, for 



BUTTERFLIES AND MOTHS. 319 

instance, of the comfnon brimstone butterfly (Gonepteryx), is of 
a far more intense yellow than the female, though she is equally 
conspicuous; and it does not seem probable that she specially 
acquired her pale tints as a protection, though it is probable 
that the male acquired his bright colors as a sexual attraction. 
The female of Anthocharis cardamines does not possess the 
beautiful orange wing-tips of the male; consequently she closely 
resembles the white butterflies (Pieris) so common in our gar- 
dens; but we have no evidence that this resemblance is bene- 
ficial to her. As, on the other hand, she resembles both sexes 
of several other species of the genus inhabiting various quarters 
of the world, it is probable that she has simply retained to a 
large extent her primordial colors. 

Finally, as we have seen, various considerations lead to the 
conclusion that with the greater number of brilliantly-colored 
Lepidoptera it is the male which has been chiefly modified 
through sexual selection; the amount of difference between the 
sexes mostly depending on the form of inheritance which has 
prevailed. Inheritance is governed by so many unknown laws 
or conditions, that it seems to us to act in a capricious manner;^** 
and we can thus, to a certain extent, understand how it is that 
with closely allied species the sexes either differ to an astonish- 
ing degree, or are identical in color. As all the successive steps 
in the process of variation are necessarily transmitted through 
the female, a greater or less number of such steps might readily 
become developed in her; and thus we can understand the fre- 
quent gradations from an extreme difference to none at all be- 
tween the sexes of allied species. These cases of gradation, it 
may be added, are much too common to favor the supposition 
that we here see females actually undergoing the process of 
transition and losing their brightness for the sake of protection; 
for we have every reason to conclude that at any one time the 
greater number of species are in a fixed condition. 

Mimicry. — This principle was first made clear in an admir- 
able paper by Mr. Bates,-^ who thus threw a flood of light on 
many obscure problems. It had previously been observed that 
certain butterflies in S. America belonging to quite distinct fam- 
ilies, resembled the Heliconidse so closely in every stripe and 
shade of color, that they could not be distinguished save by an 
experienced entomologist. As the Heliconidae are colored in 
their usual manner, whilst the others depart from the usual color- 
ing of the groups to which they belong, it is clear that the latter 

28 'The Variation of Animals and Plants under Domestication,' vol. 
ii. chap. xii. p. 17. 

29 -Transact. Linn. Soc' vol. xxiii. 1862, p. 495. 



320 THE DESCENT OF MAN. 

are the imitators, and the Heliconidse the imitated. Mr. Bates 
further observed that the imitating species are comparatively 
rare, whilst the imitated abound, and that the two sets live 
mingled together. From the fact of the Heliconidae being con- 
spicuous and beautiful insects, yet so numerous in individuals 
and species, he concluded that they must be protected from the 
attacks of enemies by some secretion or odor; and this conclusion 
has now been amply confirmed,"" especially by Mr. Belt. Hence 
Mr. Bates inferred that the butterflies which imitate the protected 
species have acquired their present marvelously deceptive ap- 
pearance through variation and natural selection, in order to be 
mistaken for the protected kinds, and thus to escape being de- 
voured. No explanation is here attempted of the brilliant colors 
of the imitated, but only of the imitating butterflies. We must 
account for the colors of the former in the same general manner, 
as in the cases previously discussed in this chapter. Since the 
publication of Mr. Bates' paper, similar and equally striking 
facts have been observed by Mr. Wallace in the Malayan region, 
by Mr. Trimen in South Africa, and by Mr. Riley in the United 
States.^^ 

As some writers have felt much difficulty in understanding 
how the first steps in the process of mimicry could have been 
effected through natural selection, it may be well to remark that 
the process probably commenced long ago between forms not 
widely dissimilar in color. In this case even a slight variation 
would be beneficial, if it rendered the one species more like the 
other; and afterwards the imitated species might b© modified to 
an extreme degree through sexual selection or other means, and if 
the changes were gradual, the imitators might easily be led along 
the same track, until they differed to an equally extreme degree 
from their original condition; and they would thus ultimately 
assume an appearance or coloring wholly unlike that of the 
other members of the group to which they belonged. It should 
also be remembered that many species of Lepidoptera are liable 
to considerable and abrupt variations in color. A few instances 
have been given in this chapter; and many more may be found 
in the papers of Mr. Bates and Mr. Wallace. 

With several species the sexes are alike, and imitate the two 
sexes of another species. But Mr. Trimen gives, in the paper 
already referred to, three cases in which the sexes of the imitated 

30 'Proc. Ent. Soc' Dec. 3rd, 1866, p. xlv. 

31 Wallace, 'Transact. Linn. Soc' vol. xxv. 1865, p. 1; alsio 'Transact. 
Ent. Soc' vol. iv. (3rd series), 1867, p. 301. Trimen, 'Linn. Transact.' 
vol. xxvi. 1869, p. 497. Riley, 'Third Annual Report on the Noxious 
Insects of Missouri,' 1871, pp. 163-168. This latter essay is valuable, as 
Mr. Riley here discusses all the objections which have been raised 
against Mr. Bates* theory. 



BUTTERFLIES AND MOTHS. 321 

form differ from each other in color, and the sexes of the imitat- 
ing form differ in a like manner. Several cases have also been 
recorded where the females alone imitate brilliantly-colored and 
protected species, the males retaining "the normal aspect of their 
"immediate congeners." It is here obvious that the successive 
variations by which the female has been modified have been 
transmitted to her alone. It is, however, probable that some 
of the many successive variations would have been transmitted 
to, and developed in, the males had not such males been elim- 
inated by being thus rendered less attractive to the females; so 
that only those variations were preserved which were from the 
first strictly limited in their transmission to the female sex. We 
have a partial illustration of these remarks in a statement by Mr. 
Belt;^^ that the males of some of the Leptalides, which imitate 
protected species, still retain in a concealed manner some of 
their original characters. Thus in the males "the upper half of 
"the lower wing is of pure white, whilst all the rest of the wings 
"is barred and spotted with black, red and yellow, like the 
"species they mimic. The females have not this white patch, and 
"the males usually conceal it by covering it with the upper wing, 
"so that I cannot imagine its being of any other use to them 
"than as an attraction in courtship, when they exhibit it to the 
"females, and thus gratify their deep-seated preference for the 
"normal color of the Order to which the Leptalides belong." 

Bright Colors of Caterpillars. — Whilst reflecting on the beauty 
of many butterflies, it occurred to me that some caterpillars were 
splendidly colored; and as sexual selection could not possibly 
have here acted, it appeared rash to attribute the beauty of the 
mature insect to this agency, unless the bright colors of their 
larvae could be somehow explained. In the first place, it may be 
observed that the colors of caterpillars do not stand in any close 
correlation with those of the mature insect. Secondly, their 
bright colors do not serve in any ordinary manner as a protection. 
Mr. Bates informs me, as an instance of this, that the most con- 
spicuous caterpillar which he ever beheld (that of a Sphinx) lived 
on the large green leaves of a tree on the open llanos of South 
America; it was about four inches in length, transversely banded 
with black and yellow, and with its head, legs, and tail of a 
bright red. Hence it caught the eye of any one who passed by, 
even at a distance of many yards, and no doubt that of every 
passing bird. 

I then applied to Mr. Wallace, who has an innate genius for 
solving difllculties. After some consideration he replied: "Most 
"caterpillars require protection, as may be inferred from some 



'The Naturalist in Nicaragua,' 1874, p. 385. 
22 



322 THE DESCENT OF MAN. 

"kinds being furnished with spines or irritating hairs, and from 
"many being colored green like the leaves on which they feed, 
"or being curiously like the twigs of the trees on which they 
"live." Another instance of protection, furnished me by Mr. J. 
Mansel Weale, may be added, namely, that there is a caterpillar 
of a moth which lives on the mimosas in South Africa, and 
fabricates for itself a case quite indistinguishable from the sur- 
rounding thorns. From such considerations Mr. Wallace thought 
it probable that conspicuously-colored caterpillars were protected 
by having a nauseous taste; but as their skin is extremely ten- 
der, and as their intestines readily protrude from a wound, a 
slight peck from the beak of a bird would be as fatal to them 
as if they had been devoured. Hence, as Mr. Wallace remarks, 
"distastefulness alone would be insuflBcient to protect a cater- 
"pillar unless some outward sign indicated to its would-be de- 
"stroyer that its prey was a disgusting morsel." Under these 
circumstances it would be highly advantageous to a caterpillar 
to be instantaneously and certainly recognized as unpalatable by 
all birds and other animals. Thus the most gaudy colors would 
be serviceable, and might have been gained by variation and the 
survival of the most easily-recognized individuals. 

This hypothesis appears at first sight very bold, but when it 
was brought before the Entomological Society^^ it was supported 
by various statements; and Mr. J. Jenner Weir, who keeps a 
large number of birds in an aviary, informs me that he has 
made many trials, and finds no exception to the rule, that all 
caterpillars of nocturnal and retiring habits with smooth skins, 
all of a green color, and all which imitate twigs, are greedily 
devoured by his birds. The hairy and spinose kinds are invari- 
ably rejected, as were four conspicuously-colored species. When 
the birds rejected a caterpillar, they plainly showed, by shaking 
their heads, and cleansing their beaks, that they were disgusted 
by the taste.^* Three conspicuous kinds of caterpillars and moths 
were also given to some lizards and frogs, by Mr. A. Butler, and 
were rejected, though other kinds were eagerly eaten. Thus the 
probability of Mr. Wallace's view is confirmed, namely, that cer- 
tain caterpillars have been made conspicuous for their own good, 
so as to be easily recognized by their enemies, on nearly the 
same principle that poisons are sold in colored bottles by drug- 

33 'Proc. Entomolog-. Soc' Dec. 3rd, 1866, p. xlv., and March 4th, 1867, 
p. Ixxx. 

3* See Mr. J. Jenner Weir's paper on Insects and Insectivorous Birds, 
in 'Transact. Ent. Soc' 1869, p. 21, also Mr. Butler's paper, ibid. p. 27. 
Mr. Riley has given analogous facts in the 'Third Annual Report on 
the Noxious Insects of Missouri,' 1871, p. 148. Some opposed cases are, 
however, given by Dr. Wallace and M. H. d'Orville; see 'Zoological 
Record,' 1869, p. 349. 



BUTTERFLIES AND MOTHS, 323 

gists for the good of man. We cannot, however, at present thus 
explain the elegant diversity in the colors of many caterpillars; 
but any species which had at some former period acquired a dull, 
mottled, or striped appearance, either in imitation of surround- 
ing objects, or from the direct action of climate, &c., almost cer- 
tainly would not become uniform in color, when its tints were 
rendered intense and bright; for in order to make a caterpillar 
merely conspicuous, there would be no selection in any definite 
direction. 

Summainj and Concluding RemarTis on Insects. — Looking back 
to the several Orders, we see that the sexes often differ in 
various characters, the meaning of which is not in the least 
understood. The sexes, also, often differ in their organs of sense 
and means of locomotion, so that the males may quickly dis- 
cover and reach the females. They differ still oftener in the 
males possessing diversified* contrivances for retaining the fe- 
males when found. We are, however, here concerned only in a 
secondary degree with sexual differences of these kinds. 

In almost all the Orders, the males of some species, even of 
weak and delicate kinds, are known to be highly pugnacious; 
and some few are furnished with special weapons for fighting 
with their rivals. But the law of battle does not prevail nearly 
so widely with insects as with the higher animals. Hence it 
probably arises, that it is in only a few cases that the males have 
been rendered larger and stronger than the females. On the 
contrary, they are usually smaller, so that they may be developed 
within a shorter time, to be ready in large numbers for the 
emergence of the females. 

In two families of the Homoptera and in three of the Orthop- 
tera, the males alone possess sound-producing organs in an 
efficient state. These are used incessantly during the breeding- 
season, not only for calling the females, but apparently for 
charming or exciting them in rivalry with other males. No 
one who admits the agency of selection of any kind, will, after 
reading the above discussion, dispute that these musical instru- 
ments have been acquired through sexual selection. In four 
other Orders the members of one sex, or more commonly of both 
sexes, are provided with organs for producing various sounds, 
which apparently serve merely as call-notes. When both sexes 
are thus provided, the individuals which were able to make the 
loudest or most continuous noise would gain partners before 
those which were less noisy, so that their organs have probably 
been gained through sexual selection. It is instructive to reflect 
on the wonderful diversity of the means for producing sound, 
possessed by the males alone, or by both sexes, in no less than 
six Orders. We thus learn how e^ectual sexual selection has 



324 THE DESCENT OF MAN. 

been in leading to modifications which sometimes, as with the 
Homoptera, relate to important parts of the organization. 

From the reasons assigned in the last chapter, it is probable 
that the great horns possessed by the males of many Lamelli- 
corn, and some other beetles, have been acquired as ornaments. 
From the small size of insects, we are apt to undervalue their 
appearance. If we could imagine a male Chalcosoma (fig. 16), 
with its polished bronzed coat of mail, and its vast complex 
horns, magnified to the size of a horse, or even of a dog, it would 
be one of the most imposing animals in the world. 

The coloring of insects is a complex and obscure subject. 
When the male differs slightly from the female, and neither are 
brilliantly-colored, it is probable that the sexes have varied 
in a slightly different manner, and that the variations have been 
transmitted by each sex to the same, without any benefit or evil 
thus accruing. When the male is brilliantly-colored and differs 
conspicuously from the female, as .with some dragon-fiies and 
many butterflies, it is probable that he owes his colors to sexual 
selection; whilst the female has retained a primordial or very 
ancient type of coloring, slightly modified by the agencies before 
explained. But in some cases the female has apparently been 
made obscure by variations transmitted to her alone, as a means 
of direct protection; and it is almost certain that she has some- 
times been made brilliant, so as to imitate other protected spe- 
cies inhabiting the same district. When the sexes resemble each 
other and both are obscurely colored, there is no doubt that they 
have been in a multitude of cases so colored for the sake of pro- 
tection. So it is in some instances when both are brightly-col- 
ored, for they thus imitate protected species, or resetnble sur- 
rounding objects such as flowers; or they give notice to their 
enemies that they are unpalatable. In other cases in which the 
sexes resemble each other and are both brilliant, especially when 
the colors are arranged for display, we may conclude that they 
have been gained by the male sex as an attraction, and have been 
transferred to the female. We are more especially led to this 
conclusion whenever the same type of coloration prevails through- 
out a whole group, and we find that the males of some species 
differ widely in color from the females, whilst others differ 
slightly or not at all, with intermediate gradations connecting 
these extreme states. 

In the same manner as bright colors have often been partially 
transferred from the males to the females, so it has been with 
the extraordinary horns of many Lamellicorn and some other 
beetles. So again, the sound-producing organs proper to the 
males of the Homoptera and Orthoptera have generally been 
transferred in a rudimentary, or even in a nearly perfect condi- 
tion, to the females; yet not sufficiently perfect to be of any use. 



SUMMARY ON INSECTS. 325 

It is also an interesting fact, as bearing on sexual selection, that 
the stridulating organs of certain male Orthoptera are not fully- 
developed until the last moult; and that the colors of certain 
male dragon-flies are not fully developed until some little time 
after their emergence from the pupal state, and when they are 
ready to breed. 

Sexual selection implies that the more attractive individuals 
are preferred by the opposite sex; and as with insects, when 
the sexes differ, it is the male which, with some rare exceptions, 
is the more ornamented, and departs more from the type to 
which the species belongs; — and as it is the male which searches 
eagerly for the female, we must suppose that the females habitual- 
ly or occasionally prefer the more beautiful males, and that these 
have thus acquired their beauty. That the females in most or 
all the orders would have the power of rejecting any particular 
male, is probable from the many singular contrivances possessed 
by the males, such as great jaws, adhesive cushions, spines, elon- 
gated legs, &c., for seizing the female; for these contrivances 
show that there is some diflaculty in the act, so that her concur- 
rence would seem necessary. Judging from what we know of the 
perceptive powers and affections of various insects, there is no 
antecedent improbability in sexual selection having come largely 
into play; but we have as yet no direct evidence on this head, 
and some facts are opposed to the belief. Nevertheless, when 
we see many males pursuing the same female, we can hardly 
believe that the pairing is left to blind chance — that the female 
exerts no choice, and is not influenced by the gorgeous colors or 
other ornaments with which the male is decorated. 

If we admit that the females of the Homoptera and Orthoptera 
appreciate the musical tones of their male partners, and that the 
various instruments have been perfected through sexual selec- 
tion, there is little improbability in the females of other insects 
appreciating beauty in form or color, and consequently in such 
characters having been thus gained by the males. But from the 
circumstance of color being so variable, and from its having been 
so often modified for the sake of protection, it is difficult to decide 
In how large a proportion of cases sexual selection has played 
a part. This is more especially difficult in those Orders, such as 
Orthoptera, Hymenoptera, and Coleoptera, in which the two 
sexes rarely differ much in color; for we are then left to mere 
analogy. With the Coleoptera, however, as before remarked, it 
is in the great Lamellicorn group, placed by some authors at 
the head of the Order, and in which we sometimes see a mutual 
attachment between the sexes, that we find the males of some 
species possessing weapons for sexual strife, others furnished 
with wonderful horns, many with stridulating organs, and others 
ornamented with splendid metallic tints. Hence it seems prob- 

22 



326 THE DESCENT OF MAN. 

able that all these characters have been gained through the same 
means, namely, sexual selection. With butterflies we have the 
best evidence, as the males sometimes take pains to display their 
beautiful colors; and we cannot believe that they would act thus, 
unless the display was of use to them in their courtship. 

When we treat of Birds, we shall see that they present in 
their secondary sexual characters the closest analogy with in- 
sects. Thus, many male birds are highly pugnacious, and some 
are furnished with special weapons for fighting with their rivals. 
They possess organs which are used during the breeding-season 
for producing vocal and instrumental music. They are frequently 
ornamented with combs, horns, wattles and plumes of the most 
diversified kinds, and are decorated with beautiful colors, all 
evidently for the sake of display. We shall find that, as with 
insects, both sexes in certain groups are equally beautiful and 
are equally provided with ornaments which are usually confined 
to the male sex. In other groups both sexes are equally plain- 
colored and unornamented. Lastly, in some few anomalous cases, 
the females are more beautiful than the males. We shall often 
find, in the same group of birds, every gradation from no difference 
between the sexes, to an extreme difference. We shall see that 
female birds, like female insects, often possess more or less plain 
traces or rudiments of characters which properly belong to the 
males and are of use only to them. The analogy, indeed, in all 
these respects between birds and insects is curiously close. What- 
ever explanation applies to the one class probably applies to the 
other; and this explanation, as we shall hereafter attempt to 
show in further detail, is sexual selection. 



FISHES. 327 



CHAPTER XII. 

SECONDARY SEXUAL. CHARACTERS OF FISHES, AMPHIBIANS, 

AND REPTILES. 

Fishes: Courtship and battles of the males— Larg-er size of the females 
— Males, bright colors and ornamental appendages; other strange 
characters— Colors and appendages acquired by the males during 
the breeding-season alone— Fishes with both sexes brilliantly colored 
— Protective colors— The less conspicuous colors of the female can- 
not be accounted for on the principle of protection — Male fishes 
building nests, and taking charge of the ova and young. Amphib- 
ians: Differences in structure and color between the sexes— Vocal 
organs. Reptiles: Chelonians— Crocodiles— Snakes, colors in some 
cases protective — Lizards, battles of — Ornamental appendages- 
Strange differences in structure between the sexes— Colorsn-Sexual 
differences almost as great as with birds. 

We have now arrived at the great sub-kingdom of the Ver- 
tebrata, and will commence with the lowest class, that of Fishes. 
The males of the Plagiostomous fishes (sharks, rays) and of 
ChimaBroid fishes are provided with claspers which serve to retain 
the female, like the various structures possessed by many of the 
lower animals. Besides the claspers, the males of many rays 
have clusters of strong sharp spines on their heads, and several 
rows along "the upper outer surface of their pectoral fins." These 
are present in the males of some species, which have other parts 
of their bodies smooth. They are only temporarily developed 
during the breeding-season; and Dr. Giinther suspects that they 
are brought into action as prehensile organs by the doubling in- 
wards and downwards of the two sides of the body. It is a re- 
markable fact that the females and not the males of some spe- 
cies, as of Raia clavata, have their backs studded with large hook- 
formed spines.^ 

The males alone of the capelin (Mallotus villosus, one of Sal- 
monidaB), are provided with a ridge of closely-set, brush-like 

lYarrell's 'Hist, of British Fishes,' vol. ii. 1836, pp. 417, 425, 436. Dr. 
Gunther informs me that the spines in R. clavata are peculiar to the 
female, 



328 THE DESCENT OF MAN. 

scales, by the aid of which two males, one on each side, hold the 
female, whilst she runs with great swiftness on the sandy beach, 
and there deposits her spawn.^ The widely distinct Monacanthus 
scopas presents a somewhat analogous structure. The male, as 
Dr. Giinther informs me, has a cluster of stiff, straight spines, 
like those of a comb, on the sides of the tail; and these in a 
specimen six inches long were nearly one and a half inches in 
length; the female has in the same place a cluster of bristles, 
which may be compared with those of a tooth-brush. In another 
species, M. peronii, the male has a brush like that possessed by 
the female of the last species, whilst the sides of the tail in the 
female are smooth. In some other species of the same genus the 
tail can be perceived to be a little roughened in the male and per- 
fectly smooth in the female; and lastly in others, both sexes have 
smooth sides. 

The males of many fish fight for the possession of the females. 
Thus the male stickleback (Gasterosteus leiurus) has been de- 
scribed as "mad with delight," when the female comes out of her 
hiding-place and surveys the nest which he has made for her. 
"He darts round her in every direction, then to his accumulated 
"materials for the nest, then back again in an instant; and as 
"she does not advance he endeavors to push her with his snout, 
"and then tries to pull her by the tail and side spine to the nest.'" 

The males are said to be polygamists;* they are extraordinarily 
bold and pugnacious, whilst "the females are quite pacific." Their 
battles are at times desperate; "for these puny combatants fasten 
"tight on each other for several seconds, tumbling over and over 
"again, until their strength appears completely exhausted." With 
the rough-tailed stickleback (G. trachurus) the males whilst fight- 
ing swim round and round each other, biting and endeavoring to 
pierce each other with their raised lateral spines. The same 
writer adds,^ "the bite of these little furies is very severe. They 
"also use their lateral spines with such fatal effect, that I have 
"seen one during a battle absolutely rip his opponent quite open, 
"so that he sank to the bottom and died." When a fish is con- 
quered, "his gallant bearing forsakes him; his gay colors fade 
"away; and he hides his disgrace among his peaceable compan- 
"ions, but is for some time the constant object of his conqueror's 
"persecution." 

The male salmon is as pugnacious as the little stickleback; 
and so is the male trout, as I hear from Dr. Giinther. Mr. Shaw 



^ 'The American Naturalist,' April, 1871, p. 119. 

3 See Mr. R. Warington's interesting articles in 'Annals and Mag-, of 
Nat. Hist.' Oct. 1S52, and Nov., 1855. 
* Noel Humphreys, 'River Gardens,' 1857. 
5 Loudon's 'Mag. of Nat. History,' vol. iii. 1830, p. 331. 



FISHES. 



32y 



saw a violent contest between two male salmon which lasted the 
whole day; and Mr. R. Buist, Superintendent of Fisheries, in- 
forms me that he has often watched from the bridge at Perth the 
males driving away their rivals, whilst the females were spawn- 




Fig. 27. Head of male common salmon (Salmo salar) during the 

breeding-season. 

[This drawing, as well as all the others in the present chapter, have 
been executed by the well-known artist, Mr. G. Ford, from specimens 
in the British Museum, under the kind superintendence of Dr. Gun- 
ther.] 

ing. The males "are constantly fighting and tearing each other 
"on the spawning-beds, and many so injure each other as to 
"cause the death of numbers, many being seen swimming near 
"the banks of the river in a state of exhaustion, and apparently 



330 THE DESCENT OP' MAN. 

*'iii a dying state."® Mr. Buist informs me, that in June, 1868, 
the keeper of the Stormontfield breeding-ponds visited the north- 
ern Tyne and found about 300 dead salmon, all of which with one 
exception were males; and he was convinced that they had lost 
their lives by fighting. 




Fig". 28. Head of female salmon. 

The most curious point about the male sahr^on is that during 
the breeding-season, besides a slight change in color, "the lower 
"jaw elongates, and a cartilaginous projection turns upwards 
"from the point, which, when the jaws are closed, occupies a 
"deep cavity between the intermaxillary bones of the upper jaw."^ 
(Figs. 27 and 28.) In our salmon this change of structure lasts 

« 'The Field,' June 29th, 1867. For Mr. Shaw's statement, see 'Edin- 
burgti Review,' 1843. Another experienced observer (Scrope's 'Days of 
Salmon Fisihing-,' p. 60) remarks that like the stag, the male would,' if 
he could, keep all other males away. 

"^ Yarrell, 'History of British Fishes,' vol. ii. 1836, p. 10. 



FISHES. 331 

only during the breeding-season; but in the Salmo lycaodon of 
N.-W. America the change, as Mr. J. K. Lord** believes, is perma- 
nent, and best marked in the older males which have previously 
ascended the rivers. In these old males the jaw becomes de- 
veloped into an immense hook-like projection, and the teeth 
grow into regular fangs, often more than half an inch in length. 
With the European salmon, according to Mr. Lloyd,^ the tem- 
porary hook-like structure serves to strengthen and protect the 
jaws, when one male charges another with wonderful violence; 
but the greatly developed teeth of the male American salmon 
may be compared v/ith the tusks of many male mammals, and 
they indicate an offensive rather than a protective purpose. 

The salmon is not the only fish in which. the teeth differ in 
the two sexes; as this is the case with many rays. In the 
thornback (Raia clavata) the adult male has sharp, pointed 
teeth, directed backwards, whilst those of the female are broad 
and flat, and form a pavement; so that these teeth differ in the 
two sexes of the same species more than is usual in distinct 
genera of the same family. The teeth of the male become sharp 
only when he is adult; whilst young they are broad and flat 
like those of the female. As so frequently occurs with secondary 
sexual characters, both sexes of seme species of rays (for instance 
R. batis), when adult, possess sharp pointed teeth; and here a 
character, proper to and primarily gained by the male, appears 
to have been transmitted to the offspring of both sexes. The 
teeth are likewise pointed in both sexes of R. maculata, but only 
when quite adult; the males acquiring them at an earlier age 
than the females. We shall hereafter meet with analogous cases 
in certain birds, in which the male acquires the plumage common 
to both sexes when adult, at a somewhat earlier age than does 
the female. With other species of rays the males even when old 
never possess sharp teeth, and consequently the adults of both 
sexes are provided with broad, flat teeth like those of the young, 
and like those of the mature females of the above-mentionea 
species.^" As the rays are bold, strong and voracious fish, we may 
suspect that the males require their sharp teeth for fighting with 
their rivals; but as they possess many parts modified and adapted 
for the prehension of the female, it is possible that their teeth 
may be used for this purpose. 

In regard to size, M. Carbonnier" maintains that the female of 
almost all fishes is larger than the male; and Dr. Giinther does 

8 'The Naturalist in Vancouver's Island,' vol. i. 1866, p. 54. 

9 'Scandinavian Adventures,' vol. i. 1854, pp. 100, 104. 

10 See Yarrell's account of the rays in his 'Hist, of British Fisihe®,* 
vol. ii. 1836, p. 416, with an excellent figure, and p. 422, 432. 

" As quoted in 'The Farmer,' 1868, p. 369. 



332 THE DESCENT OF MAN. 

not know of a single instance in which the aale is actually 
larger than the female. With some Cyprinodonts the male is 
not even half as large. As in many kinds of fishes the males 
habitually fight together, it is surprising that they have not gen- 
erally become larger and stronger than the females through the 
effects of sexual selection. The males suffer from their small 
size, for according to M. Carbonnier, they are liable to be de- 
voured by the females of their own species when carnivorous. 




Fig. 29. Callionymus lyra. Upper figure, male; lower figure, female. 
N. B. The lower figure is more reduced than the upper. 

and no doubt by other species^ Increased size must be in some 
manner of more importance to the females, than strength and 
size are to the males for fighting with other males; and this 
perhaps is to allow of the production of a vast number of ova. 

In many species the male alone is ornamented with bright 
colors; or these are much brighter in the male than the female. 
The male, also, is sometimes provided with appendages which ap- 
pear to be of no more use to him for the ordinary purposes of 
life, than are the tail feathers to the peacock. I am indebted 
for most of the following facts to the kindness of Dr. Gunther. 
There is reason to suspect that many tropical fishes differ sexually 
in color and structure; and there are some striking cases with 
our British fishes. The male Callionymus lyra has been called 



FISHES. 



333 



the gemmeous dragonet "from its brilliant gem-like colors." 
When fresh caught from the sea the body is yellow of various 
shades, striped and spotted with vivid blue on the head; the 
dorsal fins are pale brown with dark longitudinal bands; the 
ventral, caudal, and anal fins being bluish-black. The female, 
or sordid dragonet, was considered by Linnasus, and by many 
subsequent naturalists, as a distinct species; it is of a dingy red- 
dish-brown, with the dorsal fin brown and the other fins white. 




Fig. 



30. Xiphophorus Hellerii. Upper figure, male; 

female. 



lower figure. 



The sexes differ also in the proportional size of the head and 
mouth, and in the position of the eyes;^^ i^^i i\^q most striking dif- 
ference is the extraordinary elongation in the male (fig. 29) of 
the dorsal fin. Mr. W. Saville Kent remarks that this "singular 
"appendage appears from my observations of the species in con- 
"finement, to be subservient to the same end as the wattles, 
"crests, and other abnormal adjuncts of the male in gallinaceous 
"birds, for the purpose of fascinating their mates."" The young 
males resemble the adult females in structure and color. Through- 
out the genus Callionymus," the male is generally much more 
brightly spotted than the female, and in several species, not only 
the dorsal, but the anal fin is much elongated in the males. 



12 1 have drawn up this description from Tarrell's 'British Fishes,' 
vol. i. 1836, pp. 261 and 266. 

13 'Nature,' July, 1873, p. 264. 

" 'Catalogue of Acanth. Fishes in the British Museum,' by Dr. Gun- 
ther, 1861, pp. 138-151. 



334 THE DESCENT OF MAN. 

The male of the Cottus scorpius, or sea-scorpion, is slenderer 
and smaller than the female. There is also a great difference 
in color between them. It is difficult, as Mr. Lloyd^^ remarks, 
"for any one, who has not seen this fish during the spawning- 
"season, when its hues are brightest, to conceive the admixture 
"of brilliant colors with which it, in other respects so ill-favored, 
**is at that time adorned." Both sexes of the Labrus mixtus, 
although very different in color, are beautiful; the male being 
orange with bright blue stripes, and the female bright red with 
some black spots on the back. 

In the very distinct family of the Cyprinodontid® — inhabitants 
of the fresh waters of foreign lands — the sexes sometimes differ 
much in various characters. In the male of the Mollienesia peten- 
ensis,^® the dorsal fin is greatly developed and is marked with a 
row of large, round, ocellated, bright-colored spots; whilst the 
same fin in the female is smaller, of a different shape, and 
marked only with irregularly curved brown spots. In the male 
the basal margin of the anal fin is also a little produced and dark 
colored. In the male of an allied form, the Xiphophorus Hellerii 
(fig. 30), the inferior margin of the caudal fin is developed into 
a long filament, which, as I hear from Dr. Giinther, is striped with 
bright colors. This filament does not contain any muscles, and 
apparently cannot be of any direct use to the fish. As in the 
case of the Callionymus, the males whilst young resemble the 
adult females in color and structure. Sexual differences such as 
these may be strictly compared with those which are so frequent 
with gallinaceous birds." 

In a siluroid fish, inhabiting the fresh waters of South America, 
the Plecostomus barbatus^^ (fig. 31), the male has its mouth and 
inter- operculum fringed with a beard of stiff hairs, of which the 
female shows hardly a trace. These hairs are of the nature of 
scales. In another species of the same genus, soft flexible ten- 
tacles project from the front part of the head of the male, which 
are absent in the female. These tentacles are prolongations of 
the true skin, and therefore are not homologous with the stiff 
hairs of the former species; but it can hardly be doubted that 
both serve the same purpose. What this purpose may be, it is 
difficult to conjecture; ornament does not here seem probable, 
but we can hardly suppose that stiff hairs and flexible filaments 
can be useful in any ordinary way to the males alone. In that 

15 'Game Birds of Sweden,' &c., 1867, p. 466. 

10 With respect to this and the following- species I am indebted to 
Dr. Gunther for information: see, also, his paper on the 'Fishes of 
Central America,' in 'Transact. Zoolog-. Soc' vol. vi. 1868, p. 485. 

" Dr. Gunther makes this remark; 'Catalogue of Fishes in the Britisli 
Museum,' vol. iii. 1861, p. 141. 

""3 See Dr. Gunther on this genus, in 'Proc. Zoolog. Soc' 1868, p. 232. 



FISHES. 



335 




Fig-. 31. Plecostomus barbatus. Upper figure, head of male; lower 

figure, female. 



336 THE DESCENT OF MAN. 

strange monster, the Chimaera monstrosa, the male has a hook- 
shaped bone on the top of the head, directed forwards, with its 
end rounded and covered with sharp spines; in the female "this 
"crown is altogether absent," but what its use may be to the male 
is utterly unknown.^® 

The structures as yet referred to are permanent in the male 
after he has arrived at maturity; but with some Blennies, and in 
another allied genus,^'' a crest is developed on the head of the 
male only during the breeding-season, and the body at the same 
time becomes more brightly-colored. There can be little doubt 
that this crest serves as a temporary sexual ornament, for the 
female does not exhibit a trace of it. In other species of the 
same genus both sexes possess a crest, and in at least one species 
neither sex is thus provided. In many of the Chromidse, for 
instance in Geophagus and especially in Cichla, the males, as I 
hear from Professor Agassiz,^^ have a conspicuous protuberance 
on the forehead, which is wholly wanting in the females and in 
the young males. Professor Agassiz adds, "I have often observed 
"these fishes at the time of spawning when the protuberance is 
"largest, and at other seasons when it is totally wanting, and 
"the two sexes show no difference whatever in the outline of 
"the profile of the head. I never could ascertain that it subserves 
"any special function, and the Indians on the Amazon know 
"nothing about its use." These protuberances resemble, in their 
periodical appearance, the fleshy caruncles on the heads of certain 
birds; but whether they serve as ornaments must remain at 
present doubtful. 

I hear from Professor Agassiz and Dr. Giinther, that the males 
of those fishes, which differ permanently in color from the fe- 
males, often become more brilliant during the breeding-season. 
This is likewise the case with a multitude of fishes, the sexes of 
which are identical in color at all other seasons of the year. The 
tench, roach, and perch may be given as instances. The male 
salmon at this season is "marked on the cheeks with orange- 
"colored stripes, which give it the appearance of a Labrus, and 
"the body partakes of a golden orange tinge. The females are 
"dark in color, and are commonly called black-fish."^- An anal- 
ogous and even greater change takes place with the Salmo eriox 
or bull trout; the males of the char (S. umbla) are likewise at 

i» F. Buckland, in 'Land and Water,' July, 1868, p. 377, with a figure. 
Many other cases could be added of structures peculiar to the male, 
of which the uses are not known. 

20 Dr. Gunther, 'Catalogue of Fishes,' vol. iii. pp. 221 and 240. 

21 See, also, 'A Journey in Brazil,' by Prof, and Mrs. Agassiz, 1868, 
p. 220. 

M Yarrell, 'British Fishes,' vol. i 1836, pp. 10, 12, 35. 



FISHES. 337 

this season rather brighter in color than the females.-^ The 
colors of the pike (Esox reticulatus) of the United States, especi- 
ally of the male, become, during the breeding-season, exceedingly- 
intense, brilliant, and iridescent.-* Another striking instance out 
of many is afforded by the male stickleback (Gasterosteus leiu- 
rus), which is described by Mr. Warington,-^ as being then "beau- 
"tifUi beyond description." The back and eyes of the female are 
simply brown, and the belly white. The eyes of the male, on 
the other hand, are "of the most splendid green, having a metallic 
"luster like the green feathers of some humming-birds. The 
"throat and belly are of a bright crimson, the back of an ashy- 
"green, and the whole fish appears as though it were somewhat 
"translucent and glowed with an internal incandescence." After 
the breeding-season these colors all change, the throat and belly 
become of a paler red, the back more green, and the glowing tints 
subside. 

With respect to the courtship of fishes, other cases have been 
observed since the first edition of this book appeared, besides that 
already given of the stickleback. Mr. W. S. Kent says that the 
male of the Labrus mixtus, which, as we have seen, differs in 
color from the female, makes "a deep hollow in the sand of the 
"tank, and then endeavors in the most persuasive manner to in- 
"duce a female of the same species to share it with him, swim- 
"ming backwards and forwards between her and the completed 
"nest, and plainly exhibiting the greatest anxiety for her to fol- 
"low." The males of the Cantharus lineatus become, during the 
breeding-season, of deep leaden-black; they then retire from 
the shoal, and excavate a hollow as a nest. "Bach male now 
"mounts vigilant guard over his respective hollow, and vigor- 
"ously attacks and drives away any other fish of the same sex. 
"Towards his companions of the opposite sex his conduct is far 
"different; many of the latter are now distended with spawn, and 
"these he endeavors by all the means in his power to lure singly 
"to his prepared hollow, and there to deposit the myriad ova witb 
"which they are laden, which he then protects and guards with 
"the greatest care."^" 

A more striking case of courtship, as well as of display, by the 
males of a Chinese Macropus has been given by M, Carbonnier, 
who carefully observed these fishes under confinement." The 
males are most beautifully colored, more so than the females. 
During the breeding-season they contend for the possession of 

23 W. Thompson, in 'Annals and Mag. of Nat. History,' vol. vi. 1841, 
p. 440. 
"* 'The American Agriculturist,' 1868, p. 100. 
23 'Annals and Mag. of Nat. Hist.' Oct. 1852. 
2« 'Nature,' May, 1873, p. 25. 

27 'Bull, de la Soc. d'Acclimat.' Paris, July, 1869, and Jan. 1870. 
23 



338 THE DESCENT OF MAN. 

the females, and, in the act of courtship, expand their fins, 
which are spotted and ornamented with brightly colored rays, 
in the same manner, according to M. Carbonnier, as the peacock. 
They then also bound about the females with much vivacity, and 
appear by "I'etalage de leurs vives couleurs chercher a attirer 
"I'attention des femelles, lesquelles ne paraissaient indifferentes 
"a ce manege, elles nageaient avec une molle lenteur vers les 
"males et semblaient se complaire dans leur voisinage." After 
the male has won his bride, he makes a little disc of froth by 
blowing air and mucus out of his mouth. He then collects the 
fertilized ova, dropped by the female, in his mouth; and this 
caused M. Carbonnier much alarm, as he thought that they were 
going to be devoured. But the male soon deposits them in the 
disc of froth, afterwards guarding them, repairing the froth, and 
taking care of the young when hatched. I mention these par- 
ticulars because, as *we shall presently see, there are fishes, the 
males of which hatch their eggs in their mouths; and those who 
do not believe in the principle of gradual evolution might ask 
how could such a habit have originated; but the difQculty is 
much diminished when we know that there are fishes which thus 
collect and carry the eggs; for if delayed by any cause in de- 
positing them, the habit of hatching them in their mouths might 
have been acquired. 

To return to our more immediate subject. The case stands 
thus: female fishes, as far as I can learn, never willingly spawn 
except in the presence of the males; and the males never fertilize 
the ova except in the presence of the females. The males fight 
for the possession of the females. In many species, the males 
whilst young resemble the females in color; but when adult 
become much more brilliant, and retain their colors throughout 
life. In other species the males become brighter than the females 
and otherwise more highly ornamented, only during the season 
of love. The males sedulously court the females, and in one 
case, as we have seen, take pains in displaying their beauty 
before them. Can it be believed that they would thus act to no 
purpose during their courtship? And this would be the case, 
unless the females exert some choice and select those males which 
please or excite them most. If the female exerts such choice, all 
the above facts on the ornamentation of the males become at once 
intelligible by the aid of sexual selection. 

We have next to inquire whether this view of the bright colors 
of certain male fishes having been acquired through sexual selec- 
tion can, through the law of the equal transmission of characters 
to both sexes, be extended to those groups in which the males and 
females are brilliant in the same, or nearly the same degree and 
manner. In such a genus as Labrus, which includes some of the 
most splendid fishes in the world — for instance, the Peacock 



FISHES. 339 

Labrus (L. pavo), described,^* with pardonable exaggeration, as 
formed of polished scales of gold, encrusting lapis-lazuli, rubies, 
sapphires, emeralds, and amethysts — we may, with much prob- 
ability, accept this belief; for we have seen that the sexes in 
at least one species of the genus differ greatly in color. With some 
fishes, as with many of the lowest animals, splendid colors may 
be the direct result of the nature of their tissues and of the sur- 
rounding conditions, without the aid of selection of any kind. 
The gold-fish (Cyprinus auratus), judging from the analogy of the 
golden variety of the common carp, is perhaps a case in point, 
as it may owe its splendid colors to a single abrupt variation, 
due to the conditions to which this fish has been subjected under 
confinement. It is, however, more probable that these colors 
have been intensified through artificial selection, as this species 
has been carefully bred in China from a remote period.^* Under 
natural conditions it does not seem probable that beings so highly 
organized as fishes, and which live under such complex rela- 
tions, should become brilliantly colored without suffering some 
evil or receiving some benefit from so great a change, and con- 
sequently without the intervention of natural selection. 

What, then, are we to conclude in regard to the many fishes, 
both sexes of which are splendidly colored? Mr. Wallace'" be- 
lieves that the species which frequent reefs, where corals and 
other brightly-colored organisms abound, are brightly colored in 
order to escape detection by their enemies; but according to my 
recollection they were thus rendered highly conspicuous. In 
the fresh-waters of the tropics there are no brilliantly-colored 
corals or other organisms for the fishes to resemble; yet many 
species in the Amazons are beautifully colored, and many of the 
carnivorous Cyprinidae in India are ornamented with "bright 
"longitudinal lines of various tints."^^ Mr. M'Clelland, in de- 
scribing these fishes, goes so far as to suppose that "the peculiar 

28 Bory de Saint Vincent, in 'Diet. Class. d'Hist. Nat.' torn. ix. 1826, 
p. 151. 

-9 Owing to some remarks on this subject, made in my work 'On the 
Variation of Animals under Domestication,' Mr. W. F. Mayers ('Chi- 
nese Notes and Queries,' Aug. 1868, p. 123) has searched the ancient 
Chinese encyclopedias. He finds that gold-fish were first reared in con- 
finement during the Sung Dynasty, which commenced A. D. 960. In 
the year 1129 these fishes abounded. In another place it is said that 
since the year 1548 there has been "produced at Hangchow a variety 
"called the fire-fish, from its intensely red color. It is universally ad- 
"mired, and there is not a household where it is not cultivated, in 
"rivalry as to its color, and as a source of profit." 

30 'Westminster Review,' July, 1867, p. 7. 

81 'Indian Cyprinidae,' by Mr. J. M'Clelland, 'Asiatic Researches,' vol. 
Xts. part ii. 1839, p. 230. 



340 THE DESCENT OF MAN. 

"brilliancy of their colors" serves as "a better mark for king- 
"fishers, terns, and other birds which are destined to keep the 
"number of these fishes in check;" but at the present day few 
naturalists will admit that any animal has been made conspicuous 
as an aid to its own destruction. It is possible that certain fishes 
may have been rendered conspicuous in order to warn birds and 
beasts of prey that they were unpalatable, as explained when 
treating of caterpillars; but it is not, I believe, known that any 
fish, at least any fresh-water fish, is rejected from being distaste- 
ful to fish-devouring animals. On the whole, the most probable 
view in regard to the fishes, of which both sexes are brilliantly 
colored, is that their colors were acquired by the males as a 
sexual ornament, and were transferred equally, or nearly so, to 
the other sex. 

We have now to consider whether, when the male differs in a 
marked manner from the female in color or in other ornaments, 
he alone has been modified, the variations being inherited by his 
male offspring alone; or whether the female has been specially 
modified and rendered inconspicuous for the sake of protection, 
such modifications being inherited only by the females. It is 
impossible to doubt that color has been gained by many fishes 
as a protection: no one can examine the speckled upper surface 
of a flounder, and overlook its resemblance to the sandy bed of 
the sea on which it lives. Certain fishes, moreover, can through 
the action of the nervous system, change their colors in adapta- 
tion to surrounding objects, and that within a short time.^- One 
of the most striking instances ever recorded of an animal being 
protected by its color (as far as it can be judged of in preserved 
specimens), as well as by its form, is that given by Dr. Giinther^^* 
of a pipe-fish, which, with its reddish streaming filanients, is 
hardly distinguishable from the sea- weed to which it clings with 
its prehensile tail. But the question now under consideration is 
whether the females alone have been modified for this object. 
We can see that one sex will not be modified through natural se- 
lection for the sake of protection more than the other, supposing 
both to vary, unless one sex is exposed for a longer period to 
danger, or has less power of escaping from such danger than the 
other; and it does not appear that with fishes the sexes differ in 
these respects. As far as there is any difference, the males, from 
being generally smaller and from wandering more about, are 
exposed to greater danger than the females; and yet, when the 
sexes differ, the males are almost always the more conspicuously 
colored. The ova are fertilized immediately after being deposited; 
and when this process lasts for several days, as in the case of 

82 G. Pouchet, L'Institut, Nov. 1, 1871, p. 134. 

83 'Proc. Zoolog. Soc' 1865, p. 327, pi. xiv. and xv. 



FISHES. 341 

the salmon/* the female, during the whole time, is attended by 
the male. After the ova are fertilized they are, in most cases, 
left unprotected by both parents, so that the males and females, 
as far as oviposition is concerned, are equally exposed to danger, 
and both are equally important for the production of fertile ova; 
consequently the more or less brightly-colored individuals of 
either sex would be equally liable to be destroyed or preserved, 
and both would have an equal influence on the colors of their off- 
spring. 

Certain fishes, belonging to several families, make nests, and 
some of them take care of their young when hatched. Both 
sexes of the bright colored Crenilabrus massa and melops work 
together in building their nests with sea-weed, shells, &c.^^ But 
the males of certain fishes do all the work, and afterwards take 
exclusive charge of the young. This is the case with the dull- 
colored gobies,"*' in which the sexes are not known to differ in 
color, and likewise with the sticklebacks (Gasterosteus), in 
which the males become brilliantly colored during the spawning 
season. The male of the smooth-tailed stickleback (G. leiurus) 
performs the duties of a nurse with exemplary care and vigilance 
during a long time, and is continually employed in gently leading 
back the young to the nest, when they stray too far. He courage- 
ously drives away all enemies, including the females of his own 
species. It would indeed be no small relief to the male, if the fe- 
male, after depositing her eggs, were immediately devoured by 
some enemy, for he is forced incessantly to drive her from the 
nest." 

The males of certain other fishes inhabiting South America 
and Ceylon, belonging to two distinct Orders, have the extraor- 
dinary habit of hatching within their mouths or branchial cavi- 
ties, the eggs laid by the females.^^ I am informed by Professor 
Agassiz that the males of the Amazonian species which follow this 
habit, "not only are generally brighter than the females, but 
"the difference is greater at the spawning-season than at any 
"other time." The species of Geophagus act in the same manner; 
and in this genus, a conspicuous protuberance becomes developed 
on the forehead of the males during the breeding-season. Witn 



3* Yarrell, 'British Fishes,' vol. ii. p. U. 

35 According- to the observations of M. Gerbe; see Gunther's 'Record 
of Zoolog-. Literature,' 1865, p. 194. 

36 Cuvier, 'Regne Animal,' vol. ii. 1829, p. 242. 

37 See Mr. Warington' si most interesting- description of the habits of 
the Gasterosteus leiurus, in 'Annals and Mag-, of Nat. Hist.' Novem- 
ber, 1855. 

38 Prof. Wyman, in 'Proc. Boston Soc. of Nat. Hist.' Sept. 15, 1857. 
Also Prof. Turner, in 'Journal of Anatomy and Phys.' Nov. 1, 1866, 
p. 78. Dr. Gunther has likewise described other cases. 

23 



342 THE DESCENT OF MAN. 

the various species of Chromids, as Professor Agassiz likewise 
informs me, sexual differences in color may be observed, "whether 
"they lay their eggs in the water among aquatic plants, or deposit 
"them in holes, leaving them to come out without further care, 
"or build shallow nests in the river mud, over which they sit, as 
"our Pomotis does. It ought also to be observed that these sitters 
"are among the brightest s-pecies in their respective families; for 
"instance, Hygrogonus is bright green, with large black ocelli, 
"encircled with the most brilliant red." Whether with all the 
species of Chromids it is the male alone which sits on the eggs is 
not known. It is, however, manifest that the fact of the eggs 
being protected or unprotected by the parents, has had little or 
no influence on the differences in color between the sexes. It 
is further manifest, in all the cases in which the males take 
exclusive charge of the nests and young, that the destruction 
of the buighter-colored males would be far more influential on 
the character of the race, than the destruction of the brighter- 
colored females; for the death of the male during the period of 
incubation or nursing would entail the death of the young, so 
that they could not inherit his peculiarities; yet, in many of 
these very cases the males are more conspicuously colored than 
the females. 

In most of the Lophobranchii (Pipe-fish, Hippocampi, &c.) the 
males have either marsupial packs or hemispherical depressions 
on the abdomen, in which the ova laid by the female are hatched. 
The males also show great attachment to their young.^^ The 
sexes do not commonly differ much in color; but Dr. Giinther 
believes that the male Plippocampi are rather brighter than the 
females. The genus Solenostoma, however, offers a curious ex- 
ceptional case,*° for the female is much more vividly-colored and 
spotted than the male, and she alone has a marsupial sack and 
hatches the eggs; so that the female of Solenostoma differs from 
all the other Lophobranchii in this latter respect, and from almost 
all other fishes, in being more brightly-colored than the male. It 
is improbable that this remarkable double inversion of character in 
the female should be an accidental coincidence. As the males of 
several fishes, which take exclusive charge of the eggs and young, 
are more brightly-colored than the females, a,nd as here the fe- 
male Solenostoma takes the same charge and is brighter than the 
male, it might be argued that the conspicuous colors of that sex 
which is the more important of the two for the welfare of the 
offspring, must be in some manner protective. But from the 

39 Yarrell, 'Hist, of British Fishes,' vol. ii. 1836, pp. 329, 338. 

*o Dr. Gunther, since publishing- an account of this species in 'The 
Fishes of Zanzibar,' by Col. Playfair, 1866, p. 137, has re-examined the 
specimens, and has given me the above information. 



FISHES. 343 

large number of fishes, of which the males are either permanently 
or periodically brighter than the females, but whose life is not at 
all more important for the welfare of the species than that of 
the female, this view can hardly be maintained. When we treat 
of birds we shall meet with analogous cases, where there has been 
a complete inversion of the usual attributes of the two sexes, and 
we shall then give what appears to be the probable explanation, 
namely, that the males have selected the more attractive females, 
instead of the latter having selected, in accordance with the usual 
rule throughout the animal kingdom, the more attractive males. 

On the whole we may conclude, that with most fishes, in which 
the sexes differ in color or in other ornamental characters, the 
males originally varied, with their variations transmitted to the 
same sex, and accumulated through sexual selection by attracting 
or exciting the females. In many cases, however, such characters 
have been transferred, either partially or completely, to the fe- 
males. In other cases, again, both sexes have been colored alike 
for the sake of protection; but in no instance does it appear that 
the female alone has had her colors or other characters specially 
modified for this latter purpose. 

The last point which need be noticed is that fishes are known 
to make various noises, some of which are described as being 
musical. Dr. Dufosse, who has especially attended to this sub- 
ject, says that the sounds are voluntarily produced in several 
ways by different fishes: by the friction of the pharyngeal bones 
— by the vibration of certain muscles attacfied to the swim-blad- 
der, which serves as a resounding-board — and by the vibration of 
the intrinsic muscles of the swim-bladder. By this latter means 
the Trigla produces pure and long-drawn sounds which range 
over nearly an octave. But the most interesting case for us is 
that of two species of Ophidium, in which the males alone are 
provided with a sound-producing apparatus, consisting of small 
movable bones, with proper muscles, in connection with the swim- 
bladder.^^ The drumming of the Umbrinas in the European seas 
is said to be audible from a depth of twenty fathoms; and the 
fishermen of Rochelle assert "that the males alone make the 
"noise during the spawning-time; and that it is possible by imi- 
"tating it, to take them without bait."*^ From this statement, 
and more especially from the case of Ophidium, it is almost cer- 
tain that in this, the lowest class of the Vertebrata, as with so 



41 'Comptes Rendus.' Tom. xlvi, 1858, p. 353. Tom. xlvii. 1858, p. 916. 
Tom. liv. 1862, p. 393. The noise made by the Umbrinas (Sciaena aquila), 
is said by some authors to be more like that of a flute or org-an, than 
drumming: Br. Zouteveen, in the Dutch translation of this work (vol. 
li. p. 36), gives some further particulars on the sounds made by fishes. 

*2 The Rev. C. Kingsley, in 'Nature,' May, 1S70, p. 40. 



344 THE DESCENT OF MAN. 

many insects and spiders, sound-producing instruments have, at 
least in some cases, been developed through sexual selection, as a 
means for bringing the sexes together. 

AMPHIBIANS. 

Urodela. — I will begin with the tailed amphibians. The sexes 
of salamanders or newts often differ much both in color and 
structure. In some species prehensile claws are developed on 
the fore-legs of the males during the breeding-season: and at 
this season in the male Triton palmipes the hind-feet are pro- 
vided with a swimming-web, which is almost completely absorbed 
during the winter; so that their feet then resemble those of the 




Fig. 32. Triton cristatus (half natural size, from Bell's 'British Rep- 
tiles'). Upper figure, male during tlie breeding-season; lower fig- 
ure, female. 

female.*^ This structure no doubt aids the male in his eager 
search and pursuit of the female. Whilst courting her he rapidly 
vibrates the end of his tail. With our common newts (Triton 
punctatus and cristatus) a deep, much Indented crest is developed 
along the back and tail of the male during the breeding-season, 
which disappears during the winter. Mr. St. George Mivart in- 
forms me that it is not furnished with muscles, and thererore can- 
not be used for locomotion. As during the season of courtship it 
becomes edged with bright colors, there can hardly be a doubt 
that it is a masculine ornament. In many species the body presents 
strongly contrasted, though lurid tints, and these become more 
vivid during the breeding-season. The male, for instance, of our 

*3Bell, 'History of British Reptiles,' 2nd edit. 1849, pp. 156-159. 



AMPHIBIANS. 345 

common little newt (Triton punctatus) is "brownish-gray above 
"passing into yellow beneath, which in the spring becomes a rich 
"bright orange, marked everywhere with round dark spots." The 
edge of the crest also is then tipped with bright red or violet. 
The female is usually of a yellowish-brown color with scattered 
brown dots, and the lower surface is often quite plain.** The 
young are obscurely tinted. The ova are fertilized during the act 
of deposition, and are not subsequently tended by either parent. 
We may therefore conclude that the males have acquired their 
strongly-marked colors and ornamental appendages through sex- 
ual selection; these being transmitted either to the male offspring 
alone, or to both sexes. 

Anura or Batrachia. — With many frogs and toads the colors evi- 
dently serve as a protection, such as the bright green tints of tree- 
frogs and the obscure mottled shades of many terrestrial species. 
The most-conspicuously colored toad which I ever saw, the Phry- 
niscus nigricans,*^ had the whole upper surface of the body as 
black as ink, with the soles of the feet and parts of the abdomen 
spotted with the brightest vermilion. It crawled about the bare, 
sandy or open grassy plains of La Plata under a scorching sun, 
and could not fail to catch the eye of every passing creature. 
These colors are probably beneficial by making this animal known 
to all birds of prey as a nauseous mouthful. 

In Nicaragua there is a little frog "dressed in a bright livery of 
"red and blue" which does not conceal itself like most other 
species, but hops about during the daytime, and Mr. Belt says**' 
that as soon as he saw its happy sense of security, he felt sure 
that it was uneatable. After several trials he succeeded in tempt- 
ing a young duck to snatch up a young one, but it was instantly 
rejected; and the duck "went about jerking its head, as if trying 
"to throw off some unpleasant taste." 

With respect to sexual differences of color. Dr. Giinther does 
not know of any striking instance either with frogs or toads; yet 
he can often distinguish the male from the female, by the tints of 
the former being a little more intense. Nor does he know of any 
striking difference in external structure between the sexes, ex- 
cepting the prominences which become developed during the 
breeding-season on the front-legs of the male, by which he is en- 
abled to hold the female.*^ It is surprising that these animals 

** Bell, 'History of British Reptiles,' 2nd edit. 1849, pp. 146, 151. 

*5 'Zoology of the Voyag-e of the "Beagle," ' 1843. Bell, ibid. p. 49, 

*8 'The Naturalist in Nicaragua,* 1874, p. 321. 

*'7 The male alone of the Bufo sikimmensis (Dr. Anderson, 'Proc. 
Zoolog. Soc' 1871, p. 204) has two plate-like callosities on the thorax 
and certain rugosities on the fingers, which perhaps subserve the same 
end as the above-mention^ prominences. 



346 THE DESCENT OF MAN. 

have not acquired more strongly-marked sexual characters; for 
though cold-blooded their passions are strong. Dr. Giinther in- 
forms me that he has several times found an unfortunate female 
toad dead and smothered from having been so closely embraced 
by three or four males. Progs have been observed by Professor 
Hoffman in Giessen fighting all day long during the breeding- 
season, and with so much violence, that one had its body ripped 
open. 

Frogs and toads offer one interesting sexual difference, namely, 
in the musical powers possessed by the males; but to speak of 
music, when applied to the discordant and overwhelming sounds 
emitted by male bull-frogs and some other species, seems, ac- 
cording to our taste, a singularly inappropriate expression. 
Nevertheless, certain frogs sing in a decidedly pleasing manner. 
Near Rio Janeiro I used often to sit in the evening to listen to a 
number of little Hylse, perched on blades of grass close to the wa- 
ter, which sent forth sweet chirping notes in harmony. The va- 
rious sounds are emitted chiefly by the males during the breeding- 
season, as in the case of the croaking of our common frog.*^ In 
accordance with this fact the vocal organs of the males are more 
highly-developed than those of the females. In some genera the 
males alone are provided with sacs which open into the larnyx.*^ 
For instance, in the edible frog (Rana esculenta) "the sacs are 
"peculiar to the males, and become, when filled with air in 
"the act of croaking, large globular bladders, standing out one 
"on each side of the head, near the corners of the mouth." 
The croak of the male is thus rendered exceedingly powerful; 
whilst that of the female is only a slight groaning noise.^" In the 
several genera of the family the vocal organs differ considerably 
in structure, and their development in all cases may be attributed 
to sexual selection. 

REPTILES. 

Chelonia. — Tortoises and turtles do not offer well-marKed sexual 
differences. In some species, the tail of the male is longer than 
that of the female. In some, the plastron or lower surface of the 
shell of the male is slightly concave in relation to the back of the 
female. The male of the mud-turtle of the United States (Chrys- 
emys picta) has claws on its front-feet twice as long as those of 
the female; and these are used when the sexes unite.^^ With the 
huge tortoise of the Galapagos Islands (Testudo nigra) the males 
are said to grow to a larger size than the females: during the 
pairing season, and at no other time, the male utters a hoarse bei- 

*8 Bell, 'History of British Reptiles,' 1849, p. 93. 

*» J. Bishop, in 'Todd's Cyclop, of Anat. and Phys.' vol. iv. p. 1503. 

so Bell, ibid. p. 112-114. 

51 'Mr, C. J. Maynard, 'The American Naturalist,' Dec. 1869, p. 555. 



REPTILES. 347 

lowing noise, which can be heard at the distance of more than a 
hundred yards; the female, on the other hand, never uses her 
voice." 

With the Testudo elegans of India, it is said "that the combats 
"of the males may be heard at some distance, from the noise they 
"produce in butting against each other."^^ 

Croeodilia. — The sexes apparently do not differ in color; nor do 
I know that the males fight together, though this is probable, for 
some kinds make a prodigious display before the females. Bar- 
tram-^* describes the male alligator as striving to win the female 
by splashing and roaring in the midst of a lagoon, "swollen to an 
"extent ready to burst, with its head and tail lifted up, he spins 
"or twirls round on the surface of the water, like an Indian chief 
"rehearsing his feats of war." During the season of love, a musky 
odor is emitted by the submaxillary glands of the crocodile, and 
pervades their haunts.^^ 

Ophidia. — Dr. Giinther informs me that the males are always 
smaller than the females, and generally have longer and slenderer 
tails; but he knows of no other difference in external structure. 
In regard to color, he can almost always distinguish the male from 
the female by his more strongly-pronounced tints; thus the black 
zigzag band on the back of the male English viper is more dis- 
tinctly defined than in the female. The difference is much plainer 
in the rattle-snakes of N. America, the male of which, as the 
keeper in the Zoological Gardens showed me, can at once be dis- 
tinguished from the female by having more lurid yellow about its 
whole body. In S. Africa the Bucephalus capensis presents an 
analogous difference, for the female "is never so fully variegated 
"with yellow on the sides as the male."^® The male of the Indian 
Dipsas cynodon, on the other hand, is blackish-brown, with the 
belly partly black, whilst the female is reddish or yellowish-olive, 
with the belly either uniform yellowish or marbled with black. 
In the Tragops dispar of the same country, the male is bright 
green, and the female bronze-colored." No doubt the colors of 
some snakes are protective, as shown by the green tints of tree- 
snakes, and the various mottled shades of the species which live in 
sandy places; but it is doubtful whether the colors of many kinds, 
for instance of the common English snake and viper, serve to 

52 See my 'Journal of Researches During- the Voyage of the "Bea- 
"gle," ' 1845, p. 384. 

53 Dr. Gunther, 'Reptiles of British India,' 1864, p. 7. 
^ 'Travels through Carolina,' &c., 1791, p. 128. 

=^ Owen, 'Anatomy of Vertebrates,' vol. i. 1866, p= 615. 

58 Sir Andrew Smith, 'Zoolog. of S. Africa: Reptilia,' 1849, pi. s. 

" Dr. A. Gunther, 'Reptiles of British India,' Ray Soc. 1864, pp. 304, SOG. 



348 THE DESCENT OF MAN. 

conceal them; and this is still more doubtful with the many for- 
eign species which are colored with extreme elegance. The col- 
ors of certain species are very different in the adult and young 
snakes.*^^ 

During the breeding-season the anal scent-glands of snakes are 
in active function ;^^ and so it is with the same glands in lizards, 
and as we have seen with the submaxillary glands of crocodiles. 
As the males of most animals search for the females, these odorif- 
erous glands probably serve to excite or charm the female, rather 
than to guide her to the spot where the male may be found. Male 
snakes, though appearing so sluggish, are amorous; for many 
have been observed crowding round the same feihale, and even 
round her dead body. They are not known to fight together from 
rivalry. Their intellectual powers are higher than might have 
been anticipated. In the Zoological Gardens they soon learn not 
to strike at the iron bar with which their cages are cleaned; and 
Dr. Keen of Philadelphia informs me that some snakes which he 
kept, learned after four or five times to avoid a noose, with which 
they were at first easily caught. An excellent observer in Ceylon, 
Mr. E. Layard, saw®° a cobra thrust its head through a narrow hole 
and swallow a toad. "With this encumbrance he could not with- 
"draw himself; finding this, he reluctantly disgorged the precious 
"morsel, which began to move off; this was too much for snake 
"philosophy to bear, and the toad was again seized, and again 
"was the snake, after violent efforts to escape, compelled to part 
"with its prey. This time, however, a lesson had been learnt, 
"and the toad was seized by one leg, withdrawn, and then swal- 
"lowed in triurnph." 

The keeper in the Zoological Gardens is positive that certain 
snakes, for instance Crotalus and Python, distinguish him from 
all other persons. Cobras kept together in the same cage appar- 
ently feel some attachment towards each other.^^ 

It does not, however, follow because snakes have some reason- 
ing power, strong passions and mutual affection, that they should 
likewise be endowed with sufficient taste to admire brilliant colors 
in their partners, so as to lead to the adornment of the species 
through sexual selection. Nevertheless, it is difficult to account 
in any other manner for the extreme beauty of certain species; 
for instance, of the coral-snakes of S. America, which are of a 
rich red with black and yellow transverse bands. I well remember 

58 Dr. Stoliczka, 'Journal of Asiatic Soc. of Bengral,' vol. xxxix. 1870, 
pp. 205, 211. 

B9 Owen, 'Anatomy of Vertebrates,' vol. i. 1866, p. 615. 

«> 'Ilambles in Ceylon,' in 'Annals and Mag. of Nat. Hist.' 2nd series. 
vol. ix. 1852, p. 333. 

«i Dr. Gunther, 'Reptiles of British India,' 1864, p. 340. 



REPTILES. 349 

how much surprise I felt at the beauty of the first coral-snake 
which I saw gliding across a path in Brazil. Snakes colored in 
this peculiar manner, as Mr. Wallaee states on the authority of 
Dr. Giinther,^- are found nowhere else in the world except in S. 
America, and here no less than four genera occur. One of these, 
Blaps, is venomous; a second and widely-distinct genus is doubt- 
fully venomous, and the two others are quite harmless. The 
species belonging to these distinct genera inhabit the same dis- 
tricts, and are so like each other, that no one "but a naturalist 
"would distinguish the harmless from the poisonous kinds." 
Hence, as Mr. Wallace believes, the innocuous kinds have prob- 
ably acquired their colors as a protection, on the principle of imi- 
tation; for they would naturally be thought dangerous by their 
enemies. The cause, however, of the bright colors of the venom- 
ous Elaps remains to be explained, and this may perhaps be sexual 
selection. 

Snakes produce other sounds besides hissing. The deadly 
Echis carinata has on its sides some oblique rows of scales of a pe- 
culiar structure with serrated edges; and when this snake is ex- 
cited, these scales are rubbed against each other, which produces 
"a curious prolonged, almost hissing sound."^ With respect to 
the rattling of the rattle-snake, we have at last some definite in- 
formation: for Professor Aughey states,''' that on two occasions, 
being himself unseen, he watched from a little distance, a rattle- 
snake coiled up with head erect, which continued to rattle at short 
intervals for half an hour: and at last he saw another snake 
approach, and when they met they paired. Hence he is satisfied 
that one of the uses of the rattle is to bring the sexes together. 
Unfortunately he did not ascertain whether it was the male or 
the female which remained stationary and called for the other. 
But it by no means follows from the above fact that the rattle may 
not be of use to these snakes in other ways, as a warning to ani- 
mals which would otherwise attack them. Nor can I quite dis- 
believe the several accounts which have appeared of their thus 
paralyzing their prey with fear. Some other snakes also make a 
distinct noise by rapidly vibrating their tails against the surround- 
ing stalks of plants; and I have myself heard this in the case of a 
Trigonocephalus in S. America. 

Lacertilia. — The males of some, probably of many kinds of liz- 
ards fight together from rivalry. Thus the arboreal Anolis crista- 
tellus of S. America is extremely pugnacious: "During the spring 
"and early part of the summer, two adult males rarely meet with- 
es -Westminster Review,' July 1st, 1867, p. 32. 
«3 Dr. Anderson, 'Proc. Zoolog. Soc' 1871, p. 196. 
* 'The American Naturalist,' 1873, p. 85. 



350 THE DESCENT OF MAN. 

"out a contest. On first seeing one another, tliey nod their heads 
"up and down three or four times, and at the same time expand- 
"ing the frill or pouch beneath the throat; their eyes glisten with 
"rage, and after waving their tails from side to side for a few sec- 
"onds, as if to gather energy, they dart at each other furiously, 
"rolling over and over, and holding firmly with their teeth. The 
"conflict generally ends in one of the combatants losing his tail, 
"which is often devoured by the victor." The male of this species 
is considerably larger than the female;^' and this, as far as Dr. 
Gunther has been able to ascertain, is the general rule with lizards 
of all kinds. The males alone of the Cyrtodactylus rubidus of the 
Andaman Islands possesses pre -anal pores; and these pores judg- 
ing from analogy probably serve to emit an odor.*^" 

The sexes often differ greatly in various external characters. 
The male of the above-mentioned Anolis is furnished with a crest 
which runs along the back and tail, and can be erected at pleas- 
ure; but of this crest the female does not exhibit a trace. In the 
Indian Cophotis ceylanica, the female has a dorsal crest, though 
much less developed than in the male; and so it is, as Dr. Gunther 
informs me, with the females of many Iguanas, Chameleons, and 
other lizards. In some species, however, the crest is equally 
developed in both sexes, as in the Iguana tuberculata. In the 
genus Sitana, the males alone are furnished with a large throat- 
pouch (fig. 33), which can be folded up like a fan, and is colored 
blue, black, and red; but these splendid colors are exhibited only 
during the pairing-season. The female does not possess even a 
rudiment of this appendage. In the Anolis cristatellus, accord- 
ing to Mr. Austen, the throat pouch, which is bright red marbled 
with yellow, is present in the female, though in a rudimental con- 
dition. Again, in certain other lizards, both sexes are equally 
well provided with throat pouches. Here we see with species be- 
longing to the same group, as in so many previous cases, the 
same character either confined to the males, or more largely de- 
veloped in them than in the females, or again equally developed 
in both sexes. The little lizards of the genus Draco, which glide 
through the air on their rib-supported parachutes, and which in 
the beauty of their colors baffle description, are furnished with 
skinny appendages to the throat "like the wattles of gallinaceous 
birds." These become erected when the animal is excited. They 
occur in both sexes, but are best developed when the male arrives 
at maturity, at which age the middle appendage is sometimes 
twice as long as the head. Most of the species likewise have a low 

*» Mr. N. Li. Austen kept these animals alive for a considerable time; 
see 'Land and Water,' July, 1S67, p. 9. 
^^Stoliczka, 'Journal of Asiatic Soc. of Bengal,' vol. xxxiv. 1870, p. 166. 



REPTILES. 



3S1 



crest running along the neck; and this is much more developed in 
the full-grown males, than in the females or young males." 

A Chinese species is said to live in pairs during the spring; 
"and if one is caught, the other falls from the tree to the ground, 
"and allows itself to he captured with impunity" — I presume from 
despair.''^ 

There are other and much more remarkable differences between 
the sexes of certain lizards. The male of Ceratophora aspera 
bears on the extremity of his snout an appendage half as long 





Fig. 33. Sitana minor. Male with 
the g"ular pouch expanded 
(from Gunther's 'Reptiles of 
India'). 



Fig-. 34. Ceratophora Stod- 
dartii. Upper figure, 
male; lower figxire, fe- 
male. 



as the head. It is cylindrical, covered with scales, flexible, and 
apparently capable of erection: in the female it is quite rudimen- 
tal. In a second species of the same genus a terminal scale forms 
a minute horn on the summit of the flexible appendage-, and in a 
third species (C. Stoddartii, fig. 34) the whole appendage is con- 
verted into a horn, which is usually of a white color, but assumes 
a purplish tint when the animal is excited. In the adult male of 
this latter species the horn is half an inch in length, but it is of 
quite minute size in the female and in the young. These appen- 
dages, as Dr. Gtinther has remarked to me, may be compared with 
the combs of gallinaceous birds, and apparently serve as orna- 
ments. 



«7 All the foregoing statements and quotations, in regard to Cophotis, 
Sitana and Draco, as well as the following facts in regard to Cerato- 
phora and Chamaeleon, are from Dr. Gunther himself, or from his 
magnificent work on the 'Reptiles of British India,' Ray See. 1864, 
pp. 122, 130, 135. 

«s Mr. Swinhoe, 'Proc. Zoolog. Soc' 1870, p. 240. 



352 



THE DESCENT OF MAN. 



In the genus Chamgeleon we come to the acme of difference be- 
tween the sexes. The upper part of the skull of the male C. bifurcus 
(fig. 35), an inhabitant of Madagascar, is produced into two great, 
solid, bony projections, covered with scales like the rest of the 
head; and of this wonderful modification of structure the female 
exhibits only a rudiment. Again, in Chamseleon Owenii (fig. 36), 
from the West Coast of Africa, the male bears on his snout and 




Fig-. 35. Chamaeleon bifurcus. Upper figure, male; lower figure, female. 

forehead three curious horns, of which ihe female has not a trace. 
These horns consist of an excrescence of bone covered with a 
smooth sheath, forming part of the general integuments of the 
body, so that they are identical in structure with those of a bull, 
goat, or other sheathhorned ruminant. Although the three horns 
differ so much in appearance from the two great prolongations of 
the skull in C. bifurcus, we can hardly doubt that they serve the 
same general purpose in the economy of these two animals. The 



REPTILES. 



353 



first conjecture, which will occur to every one, is that they are 
used by the males for fighting together; and as these animals are 
very quarrelsome,^ this is probably a correct view. Mr. T. W. 
Wood also informs me that he once watched two individuals of 
C. pumilus, fighting violently on the branch of a tree; they flung 
their heads about and 
tried to bite each other; 
they then rested for a 
time, and afterwards 
continued their battle. 
With many lizards, 
the sexes differ slightly 
in color, the tints and 
stripes of the males be- 
ing brighter and more 
distinctly defined, than 
in the females. This, for 
instance, is the case 
with the above Cophotis 
and with the Acantho- 
dactylus capensis of S. 
Africa. In a Cordylus of 
the latter country, the 
male is either much red- 
der or greener than the 
female. In the Indian 
Calotes nigrilabris there is a still greater difference; the lips also 
of the male are black, whilst those of the female are green. In our 
common little viviparous lizard (Zootoca vivipara) "the under 
"side of the body and base of the tail in the male are bright 
'^orange, spotted with black; in the female these parts are pale- 
"grayish-green without spots."'^ We have seen that the males 
alone of Sltana possess a throat-pouch; and this is splendidly 
tinted with blue, black, and red. In the Proctotretus tenuis of 
Chile the male alone is marked with spots of blue, green, and cop- 
pery-red.'^ In many 6ases the males retain the same colors 
throughout the year, but in others they become much brighter dur- 
ing the breeding-season; I may give as an additional instance the 
Calotes maria, which at this season has a bright red head, the rest 
of the body being green.^=* 




Fig- 36. Chamaeleon Owenii. Upper 
figure, male; lower figure, female. 



69 Dr. Bucholz, 'Monatsbericht K. Pieuss. Akad.' Jan. 1874, p. 78. 

'° Bell, 'History of British Reptiles,' 2nd edit. 1849, p. 40. 

1 For Proctotretus, see 'Zoology of the Voyage of the "Beagle:" Rep- 
tiles,' by Mr. Bell, p. 8. For the Lizards of S. Africa, see 'Zoology of 
S. Africa: Reptiles,' by Sir Andrew Smith, pi. 25 and 39. For the In- 
dian Calotes, see 'Reptiles of British India,* by Dr. Gunther, p. 143, 

'2 Gunther in 'Proc. Zoolog. Soc' 1870, p. 778, with a colored figure. 
U 



354 THE DESCENT OF MAN. 

Both sexes of many species are beautifully colored exactly alike; 
and there is no reason to suppose that such colors are protective. 
No doubt with the bright green kinds which live in the midst of 
vegetation, this color serves to conceal them, and in N. Patagonia 
I saw a lizard (Proctotretus multimaculatus) which, when fright- 
ened, flattened its body, closed its eyes, and then from its mottled 
tints was hardly distinguishable from the surrounding sand. But 
the bright colors with which so many lizards are ornamented, as 
well as their various curious appendages, were probably acquired 
by the males as an attraction, and then transmitted either to their 
male offspring alone, or to both sexes. Sexual selection, indeed, 
seems to have played almost as important a part with rep- 
tiles as with birds; and the less conspicuous colors of the females 
in comparison with the males cannot be accounted for, as Mr. 
Wallace believes to be the case with birds, by the greater exposure 
of the females to danger during incubation. 



BIRDS. 355 



CHAPTER XIII. 
SECONDARY SEXUAL CflARACTERS OF BIRDS. 

Sexual differences— Law of battle— Special weapons— Vocal org-ans- In- 
strumental music— Love-antics and dances — Decorations, permanent 
and seasonal — Double and sing-le annual moults — Display of orna- 
ments by the males. 

Secondary sexual characters are more diversified and conspic- 
uous in birds, though not perhaps entailing more important 
changes of structure, than in any other class of animals. I sTiall, 
therefore, treat the subject at considerable length. Male birds 
sometimes, though rarely possess special weapons for fighting 
with each other. They charm the female by vocal or instrumental 
music of the most varied kinds. They are ornamented by all 
sorts of combs, wattles, protuberances, horns, air-distended sacks, 
top-knots, naked shafts, plumes and lengthened feathers grace- 
fully springing from all parts of the body. The beak and naked 
skin about the head, and the feathers are often gorgeously colored. 
The males sometimes pay their court by dancing, or by fantastic 
antics performed either on the ground or in the air. In one in- 
stance, at least, the male emits a musky odor, which we may sup- 
pose serves to charm or excite the female; for that excellent ob- 
server, Mr. Ramsay,^ says of the Australian muskduck (Biziura 
lobata) that "the smell which the male emits during the summer 
"months is confined to that sex, and in some individuals is re- 
"tained throughout the year; I have never, even in the breeding- 
"season, shot a female which had any smell of musk." So power- 
ful is this odor during the pairing-season, that it can be detected 
long before the bird can be seen.^ On the whole, birds appear to 
be the most aesthetic of all animals, excepting of course man, and 
they have nearly the same taste for the beautiful as we have. This 
is shown by our enjoyment of the singing of birds, and by our 
women, both civilized and savage, decking their heads with bor- 
rowed plumes, and using gems which are hardly more brilliantly 

3 'Ibis,' vol. iii. (new series) 1867, p. 414. 

2 Gould, 'Handbook to the Birds of Australia,' 1865, vol. ii. p. 383. 



356 THE DESCENT OP MAN. 

colored than the naked skin and wattles of certain birds. In man, 
however, when cultivated, the sense of beauty is manifestly a far 
more complex feeling, and is associated with various intellectual 
ideas. 

Before treating of the sexual characters with which we are here 
more particularly concerned, I may just allude to certain differ- 
ences between the sexes which apparently depend on differences in 
their habits of life; for such cases, though common in the lower, 
are rare in the higher classes. Two humming-birds belonging to 
the genus Eustephanus, which inhabit the island of Juan Fernan- 
dez, were long thought to be specifically distinct, but are now- 
known, as Mr. Gould informs me, to be the male and female of the 
same species, and they differ slightly in the form of the beak. In 
another genus of humming-birds (Grypus), the beak of the male 
is serrated along the margin and hooked at the extremity, thus 
differing much from that of the female. In the Neomorpha of 
New Zealand, there is, as we have seen, a still wider difference in 
the form of the beak in relation to the manner of feeding of the 
two sexes. Something of the same kind has been observed with 
the gold-finch (Carduelis elegans), for I am assured by Mr. J. 
Jenner Weir that the birdcatchers can distinguish the males by 
their slightly longer beaks. The flocks of males are often found 
feeding on the seeds of the teazle (Dipsacus), which they can 
reach with their elongated beaks, whilst the females more com- 
monly feed on the seeds of the betony or Scrophularia. With a 
slight difference of this kind as a foundation, we can see how the 
beaks of the two sexes might be made to differ greatly through 
natural selection. In some of the above cases, however, it is pos- 
sible that the beaks of the males may have been first modified in 
relation to their contests with other males; and that this after- 
wards led to slightly changed habits of life. 

Law of Battle. — Almost all male birds are extremely pugnacious, 
using their beaks, wings, and legs for fighting together. We see 
this every spring with our robins and sparrows. The smallest of 
all birds, namely the humming-bird, is one of the most quarrel- 
some. Mr. Gosse^ describes a battle in which a pair seized hold 
of each other's beaks, and whirled round and round, till they al- 
most fell to the ground; and M. Montes de Oca, in speaking of 
another genus of humming-bird, says that two males rarely meet 
without a fierce aerial encounter: when kept in cages "their fight- 
"ing has mostly ended in the splitting of the tongue of one of the 
"two, which then surely dies from being unable to feed."^ With 
Waders, the males of the common water-hen (Gallinula chloropus) 

3 Quoted by Mr. Gould, 'Introduction to the Trochilldae,' 1861, p. 29. 
* Gould, ibid. p. 52, 



LAW OF BATTLE. 



357 



"when pairing, fight violently for the females: they stand nearly 
"upright in the water and strike with their feet." Two were seen 
to be thus engaged for half an hour, until one got hold of the head 
of the other, which would have been killed, ha#. not the observer 
interfered; the female all the time looking on as a quiet spectator.^ 
Mr. Blyth informs me that the males of an allied bird (Gallicrex 
cristatus) are a third larger than the females, and are so pug- 




Fig. 37. The Ruff or Machetes pugnax (from Brehm's 'Thierleben'). 

nacious during the breeding-season, that they are kept by the 
natives of Eastern Bengal for the sake of fighting. Various other 
birds are kept in India for the same purpose, for instance, the 
bulbuls (Pycnonotus hasmorrhous) which "fight with great 
"spirit."® 

The polygamous ruff (Machetes pugnax, fig. 37) is notorious for 
his extreme pugnacity; and in the spring, the males, which are 
considerably larger than the females, congregate day after day at 
a particular spot, where the females propose to lay their eggs. 
The fowlers discover these spots by the turf being trampled some- 
what bare. Here they fight very much like gamecocks, seizing 
each other with their beaks and striking with their wings. The 



^ W. Thompson, 'Nat. Hist of Ireland: Birds,' vol. ii. 1850, p. 327. 
^Jerdon, 'Birds of India,' 1863, vol. ii. p. 96. 



24 



358 THE DESCENT OF MAN, 

great ruff of feathers round the neck is then erected, and accord- 
ing to Col. Montagu "sweeps the ground as a shield to defend the 
"more tender parts;" and this is the only instance known to me in 
the case of birds, of any structure serving as a shield. The ruff 
of feathers, however, from its varied and rich colors probably 
serves in chief part as an ornament. Like most pugnacious birds, 
they seem always ready to fight, and when closely confined often 
kill each other; but Montagu observed that their pugnacity be- 
comes greater during the spring, when the long feathers on their 
necks are fully developed; and at this period the least movement 
by any one bird provokes a general battle.^ Of the pugnacity of 
web-footed birds, two instances will suffice: in Guiana "bloody 
"fights occur during the breeding-season between the males of the 
"wild musk-duck (Cairina moschata) ; and where these fights have 
"occurred the river is covered for some distance with feathers."^ 
Birds which seem ill-adapted for fighting engage in fierce conflicts; 
thus the stronger males of the pelican drive away the weaker 
ones, snapping with their huge beaks and giving heavy blows 
with their wings. Male snipe fight together, "tugging and push- 
"ing each other with their bills in the most curious manner im- 
"aginable." Some few birds are believed never to fight; this is the 
case, according to Audubon, with one of the woodpeckers of the 
United States (Picus auratus), although "the hens are followed by 
even half a dozen of their gay suitors."^ 

The males of many birds are larger than the females, and this 
no doubt is the result of the advantage gained by the larger and 
stronger males over their rivals during many generations. The 
difference in size between the two sexes is carried to an extreme 
point in several Australian species; thus the male musk-duck (Bi- 
ziura) and the male Cincloramphus cruralis (allied to our pipits) 
are by measurement actually twice as large as their respective fe- 
males.^° With many other birds the females are larger than the 
males; and as formerly remarked, the explanation often given, 
namely, that the females have most of the work in feeding their 
young, will not suffice. In some few cases, as we shall hereafter 
see, the females apparently have acquired their greater size and 
strength for the sake of conquering other females and obtaining 
possession of the males. 

The males of many gallinaceous birds, especially of the polyg- 
amous kinds, are furnished with special weapons for fighting 



■7 Macgillivray, 'Hist. Brit. Birds,' vol. iv. 1852, pp. 177-181. 

8 Sir R. Schomburgk, in 'Journal of R. Geograph. Soc' vol. xiii. 1843, 
p. 31. 

'Ornithological Biography,' vol. i. p. 191. For pelicans and snipes, 
see vol. iii. pp. 138, 477. 

10 Gould, 'Handbook of Birds of Australia,' vol. i. p. 395; vol. ii. p. 383. 



LAW OF BATTLE. 359 

with their rivals, namelj'' spurs, which can be used with fearful 
effect. It has been recorded by a trustworthy writer^^ that in 
Derbyshire a kite struck at a game-hen accompanied by her chick- 
ens, when the cock rushed to the rescue, and drove his spur 
right through the eye and skull of the aggressor. The spur was 
with difiBculty drawn from the skull, and as the kite though dead 
retained his grasp, the two birds were firmly locked together; but 
the cock when disentangled was very little injured. The invin- 
cible courage of the game-cock is notorious: a gentleman who 
long ago witnessed the brutal scene, told me that a bird had both 
its legs broken by some accident in the cockpit, and the owner laid 
a wager that if the legs could be spliced so that the bird could 
stand upright, he would continue fighting. This was effected on 
the spot, and the bird fought with undaunted courage until he re- 
ceived his death-stroke. In Ceylon a closely allied, wild species, 
the Gallus Stanleyi, is known to fight desperately "in defense of 
"his seraglio," so that one of the combatants is frequently found 
dead.^- An Indian partridge (Ortygornis gularis,) the male of 
which is furnished with strong and sharp spurs, is so quarrelsome, 
"that the scars of former fights disfigure the breast of almost 
"every bird you kill."^* 

The males of almost all gallinaceous birds, even those which are 
not furnished with spurs, engage during the breeding-season in 
fierce conflicts. The Capercailzie and Black-cock (Tetrao urogallus 
and T. tetrix), which are both polygamists, have regular ap- 
pointed places, where during many weeks they congregate In 
numbers to fight together and to display their charms before the 
females. Dr. Y/. Kovalevsky informs me that in Russia he has 
seen the snow all bloody on the arenas where the capercailzie 
have fought; and the black-cocks "make the feathers fiy in every 
"direction," when several "engage in a battle royal." The elder 
Brehm gives a curious account of the Balz, as the love-dances and 
love-songs of the Black-cock are called in Germany. The bird 
utters almost continuously the strangest noises: "he holds his 
"tail up and spreads it out like a fan, he lifts up his head and neck 
"with all the feathers erect, and stretches his wings from the 
"body. Then he takes a fev/ jumps in different directions, some-- 
"times in a circle, and presses the under part of his beak so hard 
"against the ground that the chin feathers are rubbed off. Dur- 
"ing these movements he beats his wings and turns round and 
"round. The more ardent he grows the more lively he becomes, 
"until at last the bird appears like a frantic creature." At such 
times the black-cocks are so absorbed that they become almost 

"■ Mr. Hewitt, in the 'Poultry Book by Teg-etmeier,' 1866, p. 137. 
i^Layard, 'Annals and Mag. of Nat, I-Iist.' vol. xiv. 1854, p. 63, 
^3 Jerdon, 'Birds of India,' vol. iii. p. 574. 



360 THE DESCENT OF MAN. 

blind and deaf, but less so than the capercailzie: hence bird after 
bird may be shot on the same spot, or even caught by the hand. 
After performing these antics the males begin to fight: and the 
same black-cock, in order to prove his strength over several an- 
tagonists, will visit in the course of one morning several Balz- 
places, which remain the same during successive years." 

The peacock with his long train appears more like a dandy than 
a warrior, but he sometimes engages in fierce contests: the Rev. 
W. Darwin Fox informs me that at some little distance from Ches- 
ter two peacocks became so excited whilst fighting, that they flew 
over the whole city, still engaged, until they alighted on the top 
of St. John's tower. 

The spur, in those gallinaceous birds which are thus provided, 
is generally single; but Polyplectron (see fig. 51, p. 391) has two 
or more on each leg; and one of the Blood-pheasants (Ithaginis 
cruentus) has been seen with five spurs. The spurs are generally 
confined to the male, being represented by mere knobs or rudi- 
ments in the female; but the females of the Java peacock (Pavo 
muticus) and, as I am informed by Mr. Blyth, of the small fire- 
backed pheasant (Euplocamus erythropthalmus) possess spurs. 
In Galloperdix it is usual for the males to have two spurs, and for 
the females to have only one on each leg.^^ Hence spurs may 
be considered as a masculine structure, which has been occasion- 
ally more or less transferred to the females. Like most other sec- 
ondary sexual characters, the spurs are highly variable, both in 
number and development, in the same species. 

Various birds have spurs on their wings. But the Egyptian 
goose (Chenalopex segyptiaeus) has only "bare obtuse knobs," 
and these probably show us the first steps by which true spurs 
have been developed in other species. In the spur-winged goose, 
Plectropterus gambensis, the males have much larger spurs than 
the females; and they use them, as I am informed by Mr. Bartlett, 
in fighting together, so that, in this case, the wing-spurs serve 
as sexual weapons; but according to Livingstone, they are chiefly 
used in the defense of the young. The Palamedea (fig. 38) is 
armed with a pair of spurs on each wing; and these are such for- 
midable weapons, that a single blow has been known to drive a 
dog howling away. But it does not appear that the spurs in this 
case, or in that of some of the spur-winged rails are larger 
in the male than in the female.^^ In certain plovers, 



14 Brehm, 'Illust. Thierleben,' 1867, B. iv. s. 351. Some of the foregoing 
statements are taken from L. Lloyd, 'The Game Birds of Sweden,* &c., 
1867, p. 79. 

13 Jerdon, 'Birds of India: on Ithaginis,' vol. iii. p. 523; on Gallo- 
perdix, p. 541. 

16 For the Egyptian goose, see Macgillivray, 'British Birds,' vol. iv. 
p. 639. For Plectropterus, 'Livingstone's Travels,' p. 254. For Pala- 



LAW OF BATTLE. 



561 



however, tke wing-spurs must be considered as a 
sexual character. Thus in the male of our common 
peewit (Vanellus cristatus) the tubercle on the shoulder 
of the wing becomes more prominent during the breeding-season, 
and the males fight together. In some species of Lobivanellus 
a similar tubercle becomes developed during the breeding-season 
"into a short horny spur." In the Australian L. lobatus both sexes 




Fig-. 38. Palamedea cornuta (from Brehm), showing- the double wing- 
spurs, and the filament on the head. 

have spurs, but these are much larger in the males than in the 
females. In an allied bird, the Hoplopterus armatus, the spurs 
do not increase in size during the breeding-season; but these birds 
have been seen in Egypt to fight together, in the same manner 
as our peewits, by turning suddenly in the air and striking side- 



medea, Brehm's 'Thierleben,' B. iv. s. 740. See, also, en this bird 
Azara, 'Voyag-es dans FAmerique merid.' torn. iv. 1809, pp. 179, 253. 



862 THE DESCENT OF MAN. 

ways at each other, sometimes with fatal results. Thus also they 
drive away other enemies.^" 

The season of love is that of hattle; but the males of some 
birds, as of the game-fowl and ruff, and even the young males of 
the v/ild turkey and grouse,^^ are ready to fight whenever they 
meet. The presence of the female is the teterrima belli causa. 
The Bengali baboos make the pretty little males of the amadavat 
(Estrelda amandava) fight together by placing three small cages 
in a row, with a female in the middle; after a little time the two 
males are turned loose, and immediately a desperate battle en- 
sues.^" When many males congregate at the same appointed spot 
and fight together, as in the case of grouse and various other birds, 
they are generally attended by the females,-" which afterwards 
pair with the victorious combatants. But in some cases the pair- 
ing precedes instead of succeeding the combat: thus according to 
Audubon,'^ several males of the Virginian goat-sucker (Caprimul- 
gus virginianus) "court in a highly entertaining manner the fe- 
"male and no sooner has she made her choice, than her approved 
"gives chase to all intruders, and drives them beyond his domin- 
"ions." Generally the males try to drive away or kill their rivals 
before they pair. It does not, however, appear that the females 
invariably prefer the victorious males. I have indeed been as- 
sured by Dr. W. Kovalevsky that the female capercailzie some- 
times steals away with a young male who has not dared to enter 
the arena with the older cocks, in the same manner as occasionally 
happens with the does of the red-deer in Scotland. When two 
males contend in presence of a single female, the victor, no doubt, 
commonly gains his desire; but some of these battles are caused by 
wandering males trying to distract the peace of an already mated 
pair.^^ 

Even with the most pugnacious species it is probable that the 

" See, on our peewit, Mr. R. Carr in 'Land and Water,* Aug. 8th, 
1868, p. 46. In regard to Lobivanellus, see Jerdon's 'Birds of India,' 
vol. iii. p. 647, and Gould's 'Handbook of Birds of Australia,' vol. ii. 
p. 220. For the Holopterus, see Mr. Allen in the 'Ibis,' vol. v. 1863, p. 156. 

^8 Audubon, 'Ornith. Biography,' vol. ii. p. 492; vol. i. pp. 4-13. 

19 Mr. Blyth, 'Land and Water,' 1867, p. 212. 

20 Richardson on Tetrao umbellus 'Fauna Bor. Amer. : Birds,' 1831, 
p. 343. L. Lloyd, 'Game Birds of Sweden,' 1867, pp. 22, 79, on the caper- 
cailzie and black-cock. Brehm, however, asserts ('Thierleben,' &c., 
B. iv. s. 352) that in Germany the g-ray-hens do not g'enerally attend 
the Balzen of the black-cocks, but this is an exception to the common 
rule; possibly the liens may lie hidden in the surrounding- busht>s, as 
is known to be the case with the gray-hens in Scandinavia, and with 
other species in N. America. 

21 'Onithological E'ography,' vol. ii. p. 275. 

22 Brehm, 'Thierleben,' &c., B. iv. 1867, p. 990. Audubon, 'Ornith, Bi- 
ography,' vol. ii. p. 492. 



VOCAL MUSIC. 363 

pairing does not depend exclusively on the mere strength and 
courage of the male; for such males are generally decorated with 
various ornaments, which often become more brilliant during the 
breeding-season, and which are sedulously displayed before the 
females. The males also endeavor to charm or excite their mates 
by love-notes, songs, and antics; and the courtship is, in many in- 
stances, a prolonged affair. Hence it is not probable that the fe- 
males are indifferent to the charms of the opposite sex, or that 
they are invariably compelled to yield to the victorious males. 
It is more probable that the females are excited, either before or 
after the conflict, by certain males, and thus unconsciously prefer 
them. In the case of Tetrao umbellus, a good observer-^ goes so 
far as to believe that the battles of the males "are all a sham, per- 
"formed to show themselves to the greatest advantage before the 
"admiring females who assemble around; for I have never been 
"able to find a maimed hero, and seldom more than a broken 
"feather." I shall have to recur to this subject, but I may here 
add that with the Tetrao cupido of the United States, about a 
score of males assemble at a particular spot, and strutting about, 
make the whole air resound with their extraordinary noises. At 
the first answer from a female the males begin to fight furiously, 
and the weaker give way; but then, according to Audubon, both 
the victors and vanquished search for the female, so that the 
females must either then exert a choice, or the battle must be re- 
newed. So, again, with one of the field-starlings of the United 
States (Sturnella ludoviciana) the males engage in fierce conflicts, 
"but at the sight of a female they ail fly after her, as if mad."^* 

Vocal and InstruTRental Music. — With birds the voice serves to 
express various emotions, such as distress, fear, anger, triumph, or 
mere happiness. It is apparently sometimes used to excite terror, 
as in the ease of the hissing noise made by some nestling-birds. 
Audubon-^ relates that a night-heron (Ardea nycticorax, Linn.) 
which he kept tame, used to hide itself when a cat approached, 
and then "suddenly start up uttering one of the most frightful 
"cries, apparentl3'- enjoying the cat's alarm and flight." The 
common domestic cock clucks to the hen, and the hen to her 
chickens, when a dainty morsel is found. The hen, when she 
has laid an q^^, "repeats the same note very often, and concludes 
"with the sixth above, which she holds for a longer time;"^^ and 
thus she expresses her joy. Some social birds apparently call to 

23 'Land and Water,' July 25th, 1868, p. 14. 

2* Audubon's 'Ornitholog. Biography;' on Tetrao cupido, vol. ii. p. 492; 
on the Sturnus, vol. ii. p. 219. 
-^ 'Ornithological Biograph.' vol. v. p. 601. 
2« The Hon. Daines Barrington, 'Philosoph. Transact.' 1773, p. 252. 



364 THE DESCENT OP MAN. 

each other for aid; and as they flit from tree to tree, the flock is 
kept together by chirp answering chirp. During the nocturnal 
migrations of geese and other water-fowl, sonorous clangs from 
the van may be heard in the darkness overhead, answered by 
clangs in the rear. Certain cries serve as danger signals, which, 
as the sportsman knows to his cost, are understood by the same 
species and by others. The domestic cock crows, and the hum- 
ming-bird chirps, in triumph over a defeated rival. The true 
song, however, of most birds and various strange cries are chiefly 
uttered during the breeding-season, and serve as a charm, or 
merely as a call-note, to the other sex. 

Naturalists are much divided with respect to the object of the 
singing of birds. Few more careful observers ever lived than 
Montagu, and he maintained that the "males of song-birds and of 
"many others do not in general search for the female, but, on the 
"contrary, their business in the spring is to perch on some con- 
"spicuous spot, breathing out their full and amorous notes, which, 
"by instinct, the female knows, and repairs to the spot to choose 
"her mate."-^ Mr. Jenner Weir informs me that this is certainly 
the case with the nightingale. Bechstein, who kept birds during 
his whole life, asserts, "that the female canary always chooses the 
"best singer, and that in a state of nature the female finch selects 
"that male out of a hundred whose notes please her most."-" 
There can be no doubt that birds closely attend to each other's 
song. Mr. Weir has told me of the case of a bullfinch which 
had been taught to pipe a German waltz, and who was so good 
a performer that he cost ten guineas; when this bird was first 
introduced into a room where other birds were kept and he began 
to sing, all the others, consisting of about twenty linnets and 
canaries, ranged themselves on the nearest side of their cages, 
and listened with the greatest interest to the new performer. 
Many naturalists believe that the singing of birds is almost exclu- 
sively "the effect of rivalry and emulation," and not for the sake 
of charming their mates. This was the opinion of Daines Bar- 
rington and White of Selborne, who both especially attended to 
this subject.^® Barrington, however, admits that "superiority in 
"song gives to birds an amazing ascendancy over others, as is 
"well known to bird-catchers." 

It is certain that there is an intense degree of rivalry between 
the males in their singing. Bird-fanciers match their birds to 
see which will sing longest; and I was told by Mr. Yarrell that 



27 'Onithological Dictionary.' 1833, p. 475. 

28 'Naturg-eschichte der Stubenvogel,' 1840, s. 4. Mr. Harrison Weir 
likewise writes to me:— "I am informed that the best singing males 
"generally get a mate first, when they are bred in the same room." 

2» 'Philosophical Transactions,' 1773, p. 263. White's 'Natural History 
of Selborne,' 1825, vol. i. p. 246. 



VOCAL MUSIC. 365 

a first-rate bird will sometimes sing till lie drops down almost 
dead, or according to Beclistein,^° quite dead from rupturing a 
vessel in the lungs. Whatever the cause may be, male birds, as 
I hear from Mr. Weir, often die suddenly during the season of 
song. That the habit of singing is sometimes quite independent 
of love is clear, for a sterile, hybrid canary-bird has been de- 
scribed^^ as singing whilst viewing itself in a mirror, and then 
dashing at its own image; it likewise attacked with fury a fe- 
male canary, when put into the same cage. The jealousy excited 
by the act of singing is constantly taken advantage of by bird- 
catchers; a male, in good song, is hidden and protected, whilst a 
stuffed bird, surrounded by limed twigs, is exposed to view. In 
this manner, as Mr. Weir informs me, a man has in the course of 
a single day caught fifty, and in one instance seventy, male chaf- 
finches. The power and inclination to sing differ so greatly with 
birds that although the price of an ordinary male chaffinch is 
only sixpence, Mr. Weir saw one bird for which the bird-catcher 
asked three pounds; the test of a really good singer being that 
it will continue to sing whilst the cage is swung round the owner's 
head. 

That male birds should sing from emulation as well as for 
charming the female, is not at all incompatible; and it might 
have been expected that these two habits would have concurred, 
like those of display and pugnacity. Some authors, however, 
argue that the song of the male cannot serve to charm the female, 
because the females of some few species, such as of the canary, 
robin, lark, and bullfinch, especially when in a state of widowhood, 
as Bechstein remarks, pour forth fairly melodious strains. In 
some of these cases the habit of singing may be in part attributed 
to the females having been highly fed and confined,'^- for this 
disturbs all the usual functions connected with the reproduction 
of the species. Many instances have already been given of the 
partial transference of secondary masculine characters to the fe- 
male, so that it is not at all surprising that the females of some 
species should possess the power of song. It has also been argued, 
that the song of the male cannot serve as a charm, because the 
males of certain species, for instance of the robin, sing during 
the autumn.^^ But nothing is more common than for animals to 
take pleasure in practicing whatever instinct they follow at other 
times for some real good. How often do we see birds which fly 
easily, gliding and sailing through the air obviously for pleasure? 



30 'Naturg-esch. der Stubenvogel,' 1840, s. 252. 

=51 Mr. Bold, 'Zoologist,' 1843-44, p. 659. 

^- D. Barring-ton, 'Phil. Transact.' 1773, p. 262. Bechstein, 'Stuben- 
vog-el,' 1840, s. 4. 

33 This is likewise the case with the water-ouzel, see Mr. Hepburn in 
the 'Zoologist,' 1845-1848, p. 1068. 



366 THE DESCENT OF MAN. 

The cat plays with the captured mouse, and the cormorant with 
the captured fish. The weaver-bird (Ploceus), when confined in a 
cage, amuses itself by neatly weaving blades of grass between 
the wires of its cage. Birds which habitually fight during the 
breeding-season are generally ready to fight at all times; and 
the males of the capercailzie sometimes hold their Balzen or leks 
at the usual place of assemblage during the autumn."-* Hence 
it is not at all surprising that male birds should continue singing 
for their ov/n amusement after the season for courtship is over. 

As shown in a previous chapter, singing is to a certain extent 
an art, and is much improved by practice. Birds can be taught 
various tunes, and even the unmelodious sparrow has learnt to 
sing like a linnet. They acquire the song of their foster parents,=^^^ 
and sometimes that of their neighbors.''' All the common song- 
sters belong to the Order of Insessores, and their vocal organs are 
much more complex than those of most other birds; yet it is a 
singular fact that some of the Insessores, such as ravens, crows, 
and magpies, possess the proper apparatus,"' though they never 
sing, and do not naturally modulate their voices to any great ex- 
tent. Hunter asserts^^ that with the true songsters the muscles 
of the larynx are stronger in the males than in the females; but 
with this slight exception there is no difference in the vocal or- 
gans of the two sexes, although the males of most species sing 
so much better and more continuously than the females. 

It is remarkable that only small birds properly sing. The 
Australian genus Menura, however, must be excepted; for the 
Menura Alberti, which is about the size of a half-grown turkey, 
not only mocks other birds, but "its own whistle is exceedingly 
"beautiful and varied." The males congregate and form "cor- 
roborying places," where they sing, raising and spreading their 
tails like peacocks, and drooping their wings."^ It is also remark- 
able that birds which sing well are rarely decorated with brilliant 
colors or other ornaments. Of our British birds, excepting the 
bullfinch and goldfinch, the best songsters are plain-colored. The 
kingfisher, bee-eater, roller, hoopoe, woodpeckers, «&e., utter harsh 
cries; and the brilliant birds of the tropics are hardly ever song- 



3* L. Lloyd, 'Game Birds of Sweden,' 1867, p. 25. 

33 Barrington, ibid. p. 264. Bechstein, ibid. s. 5. 

36 Bureau de la Malle gives a curious instance ('Annales des Sc. 
Nat.' 3rd series, Zoolog. torn. x. p. 118) of some wild blackbirds in his 
garden in Paris which naturally learnt a republican air from a caged 
bird. 

S7 Bishop, in 'Todd's Cyclop, of Anat. and Phys.' vol. iv. p. 1496. 

38 As stated by Barrington in 'Philosoph. Transact.' 1773, p. 262. 

3» Gould, 'Handbook to the Birds of Australia,' vol. i. 1865, pp. 308-310. 
See also Mr. T. W. Wood in the 'Student,' April 1870, p. 125. 



VOCAL MUSIC. 



367 



sters.** Hence bright colors and the power of song seem to re- 
place each other. We can perceive that if the plumage did not 
vary in brightness, or if bright colors were dangerous to the spe- 
cies, other means would be employed to charm the females; and 
melody of voice offers one such means. 



ikdiMil^^ 





In some birds the vocal organs differ greatly in the two sexes. 
In the Tetrao cupido (fig. 39) the male has two bare, orange- 
colored sacks, one on each side of the neck; and these are largely 
inflated when the male, during the breeding-season, makes his 
curious hollow soun