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Full text of "The descent of man, and selection in relation to sex"

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THE DESCENT OF MAN, 



AND 



SELECTION IN KELATION TO SEX. 











Phot. Druck v. A. Naumann & Schroeder, Leipzig. 



C. Lehr d. J. sculp 





o 



THE 







. /TV 4 



DESCENT OF MAN, 



AND 



SELECTION W KELATION TO SEX. 



By CHAKLES DARWIN, M.A., F.R.S., &c. 



IN TWO VOLUMES.— Vol. I, 



WITH ILLUSTRATIONS. 




LONDON: 
JOHN MURRAY, ALBEMARLE . STREET. 

1871. 



[The right of Translation is reserved.'} 



BY THE SAME AUTHOR. 



K>» 

ON THE ORIGIN OF SPECIES BY MEANS OF NATURAL 

SELECTION ; or, The Preservation of Favoured Races in the Struggle 
for Life; Fifth Edition {Tenth Thousand), with Additions and Corrections. 
1869. Murray. 

THE VARIATION OF ANIMALS AND PLANTS UNDER 

DOMESTICATION. In two vols. With Illustrations. 1868. Murray. 

ON THE VARIOUS CONTRIVANCES by which BRITISH 

AND FOREIGN ORCHIDS ARE FERTILISED BY INSECTS ; and on the 
Good Effects of Crossing. With numerous Woodcuts. Murray. 

A NATURALIST'S VOYAGE ROUND THE WORLD ; or, 

A Journal of Researches into the Natural History and Geology of the 
Countries visited during the voyage of H.M.S. ' Beagle,' under the command of 
Captain FitzRoy, R.N. Eleventh Thousand. Murray. 

ON THE STRUCTURE AND DISTRIBUTION OF CORAL 

REEFS. Smith, Elder, & Co. 

GEOLOGICAL OBSERVATIONS ON VOLCANIC ISLANDS. 

Smith, Elder, & Co. 

GEOLOGICAL OBSERVATIONS ON SOUTH AMERICA. 

Smith, Elder, & Co. 

A MONOGRAPH OF THE CIRRIPEDIA. With numerous 

Illustrations. 2 vols. 8vo. Hardwickb. 

ON THE MOVEMENTS AND HABITS OF CLIMBING 

PLANTS. With Woodcuts. Williams & Norgate. 



LONDON : PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET, 

AND CHARING CROSS. 



CONTENTS. 



Introduction Pa«;e 1-5 



PART I. ^>\CA/ 

ON THE DESCENT OF MAN. /v> rt oS a, 

— ° — / rw ^ "^ < *"' 

CHAPTER I. , J L16R AR 

The Evidence of the Descent op man from Wfe\ ^k***'**' 

Lower Form. \<xV^7/ 
Nature of the evidence bearing on the origin of man — Homb^g^^s ^ | 
structures in man and the lower animals — Miscellaneous pomt 
of correspondence — Development — Eudimentary structures, 
muscles, sense-organs, hair, hones, reproductive organs, &c. — 
The bearing of these three great classes of facts on the origin of 
man 9-33 

CHAPTER II. 

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 — C uriosity — Imitation — Attention — Mem ory — Ima- 
gination — Keason — Progressive improvement — Tools and 
weapons used by animals — Language — Self-consciousness — 
Sense of beauty — Belief in God, spiritual agencies, superstitions 

34-69 



CHAPTER III. 

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 in- 
stincts — Man a social animal — The more enduring social instincts 

2 4 



VI CONTENTS OF VOL. 1. 

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 — Trans- 
mission of moral tendencies — Summary .. .. Page 70-106 

CHAPTEE IV. 

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 
increased use and disuse of parts — Arrested development — Ee- 
version — Correlated variation — Eate 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 — Decrease in size of the canine teeth — Increased 
size and altered shape of the skull — Nakedness — Absence of 
a tail — Defenceless condition of man 107-157 



CHAPTEE V. 

On the Development of the Intellectual and Moral 
Faculties during Primeval and Civilised Times. 

The 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 
selection as affecting civilised nations — Evidence that civilised 
nations were once barbarous"' 158-184 



CHAPTEE VI. 

On the Affinities and Genealogy of Man. 

Position of man in the animal series — The natural system genea- 
logical — Adaptive characters of slight value — Similar small 
points of resemblance between man and the Quadrumana — 
Eank of man in the natural system — Birthplace and antiquity 



CONTENTS OF VOL. I. 



Vll 



of man — Absence of fossil connecting-links — Lower stages in 
the genealogy of man, as inferred, firstly from his affinities and 
secondly from bis structure — Early androgynous condition of 
the Vertebrata — Conclusion .. ..... .. Page 185-213 



CHAPTER VII. 

Ox THE 1'vACES OF MAN. 

The nature and value of specific characters — Application to the races 
of man — Arguments in favour of, and opposed to, ranking the 
so-called races of man as distinct species — Sub-species — Mono- 
genists 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 ex- 
tinction of races — The formation of races — The effects of cross- 
ing—Slight influence of the direct action of the conditions of life 
— Slight or no influence of natural selection — Sexual selection 

214-250 



PART II. 



SEXUAL SELECTION. 



*& 



CHAPTER VIII. 

Principles of Sexual Selection. 






m 



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 — Relations 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 — On the limita- 
tation of the numbers of the two sexes through natural selection 

253-320 



Vlll CONTENTS OF VOL. I. 



CHAPTER IX. 



Secondary Sexual Characters in the Lower Classes of 

the Animal Kingdom. 

These characters absent in the lowest classes — Brilliant colours — 
Mollusca — Annelids — Crustacea, secondary sexual characters 
strongly developed ; dimorphism ; colour ; characters not acquired 
before maturity — Spiders, sexual colours of ; stridulation by the 
males — Myriapoda Page 321-340 

CHAPTER X. 

Secondary Sexual Characters of Insecst. 

Diversified structures possessed by the males for seizing the females 
— Differences between the sexes, of which the meaning is 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 ; colours — 
Neuroptera, sexual differences in colour — Hymenoptera, pug- 
nacity and colours — Coleoptera, colours ; furnished with great 
horns, apparently as an ornament ; battles ; stridulating organs 
generally common to both sexes 341-385 

CHAPTER XI. 

Insects, continued. — Order Lefidoptera. 

Courtship of butterflies — Battles — Ticking noise — Colours com- 
mon to both sexes, or more brilliant in the males — Examples — 
Not due to the direct action of the conditions of life — Colours 
adapted for protection — Colours of moths — Display — Per- 
ceptive powers of the Lepidoptera ■ — Variability — Causes of the 
difference in colour between the males and females — Mimickry, 
female butterflies more brilliantly coloured than the males — 
Bright colours of caterpillars — Summary and concluding re- 
marks on the secondary sexual characters of insects — Birds 
and insects compared 386-423 



THE DESCENT OE MAN; 



AND ON 



SELECTION IN BELATION TO SEX. 



INTRODUCTION. 

The nature of the following work will be best under- 
stood 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 determination not to 
publish, as I thought that I should thus only add to 
the prejudices against my views. It seemed to me suffi- 
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 
anv general conclusion respecting his manner of appear- 
ance on this earth. Now the case wears a wholly dif- 
ferent 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 soutenir la creation independante 
" et de toutes pieces, des especes," it is manifest that at 
least a large number of naturalists must admit that 
species are the modified descendants of other species ; 

VOL. I. B 



2 INTRODUCTION. 

and this especially holds good with the younger and 
rising naturalists. 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 honoured 
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 other men, 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 appli- 
cable 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 argu- 
ments derived from the nature of the affinities which 
connect together whole groups of organisms — their geo- 
graphical distribution in past and present times, and 
their geological succession. The homological structure, 
embryological development, and rudimentary organs of 
a species, whether it be man or any other animal, to 
which our attention may be directed, remain to be con- 
sidered ; but these great classes of facts afford,- as it 
appears to me, ample and conclusive evidence in favour 
of the principle of gradual evolution. The strong sup- 
port 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-existing form ; secondly, the manner of 



INTRODUCTION. 6 

his development ; and thirdly, the value of the differ- 
ences between the so-called races of man. As I shall 
confine myself 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 dis- 
cussed in many valuable works. The high antiquity of 
man has recently been demonstrated by the labours 
of a host of eminent meD, 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 difference between 
man and the anthropomorphous apes ; for Prof. Huxley, 
in the opinion of most competent judges, has conclu- 
sively shewn that in every single visible character man 
differs less from the higher apes tban 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 little, and not those who know much, 
who so positively assert that this or that problem will 
never be solved by science. The conclusion that man is 
the co-descendant with other species of some ancient, 
lower, and extinct form, is not in any degree new. La^ 

b 2 



3 INTRODUCTION. 

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, Kolle, &c.,' and especially by 
Hackel. This last naturalist, besides his great work, 
' Generelle Morphologie ' (I860), has recently (1868, 
with a second edit, in 1870), published his ' Natiirliche 
Schopfungsgeschichte,' in which he fully discusses the 
genealogy of man. If this work had appeared before 
my essay had been written, I should probably never 
have completed it. Almost all the conclusions at which 
I have arrived 1 find confirmed by this naturalist, whose 
knowledge on many points is much fuller than mine. 
Wherever 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 manu- 
script, occasionally giving in the foot-notes references 
to his works, as a confirmation of the more doubtful or 
interesting points. 

During many years it has seemed to me highly pro- 
bable that sexual selection has played an important 
part in differentiating the races of man; but in my 

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 
England, I will give them : — ' Sechs Vorlesungen iiber die Darwin'- 
sche Theorie:' zweite Auflage, 1868, von Dr. L. Biichner ; translated 
into French under the title ' Conferences sur la Theorie Darwinienne,' 
1869. ' Der Mensch,, im Lichte der Darwin'sche Lehre,' 1865, von 
Dr. F. Kolle, 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 ('Annuario della Soc. d. Nat.,' Modena, 1867, p. 81) a 
very carious paper on rudimentary characters, as bearing on the origin 
of man. Another work has (1869) been published by Dr. Barrage. 
Francesco, bearing in Italian the title of " Man, made in the imaee of 
God, was also made in the image of the ape." 



INTRODUCTION. 

'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. 2 Consequently 
the second part of the present work, treating of sexual 
selection, has extended to an inordinate length, com- 
pared 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 w T as called to this 
subject many years ago by Sir Charles Bell's admirable 
work. This illustrious anatomist maintains that man 
is endowed with certain muscles solely for the sake 
of expressing his emotions. As this view is obviously 
opposed 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, which is 
partially completed, for separate publication. 



2 Prof. Hiickel is the sole author who, since the publication of the 
' Origin,' has discussed, in his various works, in a very able manner 
the subject of sexual selection, and has seen its full importance. 






-7 



II! RV 



Part I. 



THE DESCENT OR ORIGIN OF MAN. 



■CN V 0° S " 

&\ - 



p ART I.—THE DESCENT OF MAN. 



CHAPTEK 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 
descendant 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 transmitted to his offspring 
in accordance with the laws which prevail with the lower 
animals; such as that of the transmission of characters 
to the same age or sex. Again, are the variations the re- 
sult, 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 in- 
stance by correlation, the inherited effects of use and 
disuse, &c. ? Is man subject to similar malconformations, 
the result of arrested development, "of reduplication of 
parts, &o, 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 animals, has given rise to varieties and 
sub-races, differing but slightly from each other, or to 



10 THE DESCENT OF MAN. Part I. 

races differing so much that they must be classed as 
doubtful species ? How are such races distributed over 
the world ; and how, when crossed, do thev react on 
each other, both in the first and succeeding genera- 
tions ? 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 severe struggles for existence, and 
consequently to beneficial variations, 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 each other, so that 
some finally become extinct? We shall see that all 
these questions, as indeed is obvious in respect to most 
of them, must be answered in the affirmative, in the 
same manner as with the lower animals. But the 
several considerations just referred to may be conve- 
niently 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 the 
two succeeding chapters the mental powers of man, in 
comparison with those of the lower animals, will be con- 
sidered. 

The Bodily Structure of Man. — It is notorious that 
man is constructed on the same general type or model 
with other mammals. All the bones in his skeleton 
can be compared with corresponding bones in a monkey, 
bat, or seal. So it is with his muscles, nerves, blood- 
vessels and internal viscera. The brain, the most im- 
portant of all the organs, follows the same law, as shewn 
by Huxley and other anatomists. Bischoff, 1 who is a 
hostile witness, admits that every chief fissure and fold 



1 ' Grosslrirawmdungen des Menschen/ 1S(3S, s. 96. 



Chap. I. HOMOLOGICAL STRUCTURE. 11 

in the brain of man has its analogy in that of the orang ; 
but he acids that at no period of development do their 
brains perfectly agree ; nor could this be expected, for 
otherwise their mental powers would have been the same. 
Vulpian 2 remarks : " Les differences reelles qui existent 
" entre l'encephale de l'homme et celui des singes supe- 
" rieurs, sont bien minimes. II ne faut pas se faire 
" d'illusions a cet egard. L'homme est bien plus ~pves 
" des singes anthropomorphes par les caracteres anato- 
(S miques de son cerveau que ceux-ci ne le sont non- 
" seulement des autres mammiferes, mais memes de 
" certains quadrumanes, des guenons et des macaques." 
But it would be superfluous here to give further details 
on the correspondence between man and the higher 
mammals in the structure of the brain and all other 
parts of the body. 

It may, however, be worth while to specify a few 
points, not directly or obviously connected with struc- 
ture, by which this correspondence or relationship is 
well shewn. 

Man is liable to receive from the lower animals, and 
to communicate to them, certain diseases as hydro- 
phobia, variola, the glanders, &c. ; and this fact proves 
the close similarity of their tissues and blood, both in 
minute structure 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, 3 who carefully observed for a long 
time the Cebus Azarss in its native land, found it liable 
to catarrh, with the usual symptoms, and which when 



2 'Lee. sur la Phys.' 1866, p. 890, as quoted by M. Dally, 'L'Ordre 
des Primates et le Transformisme,' 1868, p. 29. 

3 ' Naturgeschickte der S'augethiere von Paraguay,' 1S30, s. 50. 



12 THE DESCENT OF MAN. Part I. 

often recurrent led to consumption. These monkeys 
suffered also from apoplexy, inflammation of the bowels, 
and cataract in the eye. The younger ones when shed- 
ding 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 
spirituous liquors : they will also, as I have myself seen, 
smoke tobacco with pleasure. Brehm asserts that the 
natives of north-eastern xAirica 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 behaviour 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. 4 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 simi- 
larly their whole nervous system is affected. 

Man is infested with internal parasites, sometimes 
causing fatal effects, and is plagued by external para- 
sites, all of which belong to the same genera or families 
with those infesting other mammals. Man is subject like 
other mammals, birds, and even insects, to that mys- 
terious law, which causes certain normal processes, such 
as gestation, as well as the maturation and duration of 
various diseases, to follow lunar periods. 5 His wounds 



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

5 With respect to insects see Dr. Laycock ' On a General Law of 
Vital Periodicity,' British Association, 1842. Dr. Macculloch, ' Silli- 



Chap. I. HOMOLOGICAL STRUCTURE. 13 

are repaired by the same process of healing ; and the 
stumps left after the amputation of his limbs occa- 
sionally possess, especially during an early embryonic 
period, some power of regeneration, as in the lowest 
animals. 6 

The whole process of that most important function, 
the reproduction of the species, is strikingly the same 
in all mammals, from the first act of courtship by the 
male 7 to the birth and nurturing of the young. Mon- 
keys 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. 8 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. 9 Man 



man's North American Journal of Science,' vol. xvii. p. 305, lias seen 
a dog suffering from tertian ague. 

6 I have given the evidence on this head in my ' Variation of 
Animals and Plants under Domestication,' vol. ii. p. 15. 

" " Mares e diversis generibus Quadrumanorum sine dubio dignoseunt 
" feminas hum anas a maribus. Primum, credo, odoratu, postea aspectu. 
" Mr. Youatt, qui diu in Hortis Zoologicis (Bestiariis) medicus animal- 
" ium erat, vir in rebus observandis cautus et sagax, hoc mibi certissime 
" probavit, et curatores ejusdem loci et alii e ministris confirmaverunt. 
' ' Sir Andrew Smith et Brelim notabant idem in Cynocephalo. Illus- 
" trissimus Cuvier etiam narrat multa de hac re qua ut opinor nihil 
" turpius potest indicari inter omnia liominibus et Quadrumanis com- 
*' munia. 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." 

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

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



14 THE DESCENT OF MAN. Part I. 

differs from woman in size, bodily strength, hairyness, 
&c, as well as in mind, in the same manner as do the 
two sexes of many mammals. It is, in short, scarcely 
possible to exaggerate the close correspondence in gene- 
ral structure, in the minute structure of the tissues, in 
chemical composition and in constitution, between man 
and the higher animals, especially the anthropomor- 
phous apes. 

Embryonic 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 members of the verte- 
brate 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 developed, "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 funda- 
" mental form." It is, says Prof. Huxley, 10 " 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 assertion may appear to be, it is demonstrably 
" true." 

As some of my readers may never nave seen a draw- 
ing of an embryo, I have given one of man and another 
of a dog, at about the same early stage of development, 



10 ' Man's Place in Nature,' 1SC3, p. 67. 



Chap. I. 



EMBRYONIC DEVELOPMENT. 



15 





Fig. 1 . Upper figure human embryo, from Ecker. Lower figure that of a dog, 

f'om Bischoff. 



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

b. Mid-brain, corpora quadrigemina. 

c. Hind-brain, cerebellum, medulla ob 
longata. 

d. Eye. 

e. Ear. 

/. First visceral arch. 



g. Second visceral arch. 
H. Vertebral columns and muscles in 
process of development. 
i. Anterior ) 
K. Posterior } extremities. 

L. Tail or os coccyx. 



16 THE DESCENT OF MAN. Part I. 

carefully copied from two works of undoubted accu- 



racy. 11 



After the foregoing statements made by such high 
authorities, it would be superfluous on my part to give 
a number of borrowed details, shewing that the embryo 
of man closely resembles that of other mammals. It 
may, however, be added that the human embryo like- 
wise resembles in various points of structure cer- 
tain low forms when adult. 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 considerably 
" beyond the rudimentary legs." 12 In the embryos of 
all air-breathing vertebrates, certain glands called the cor- 
pora Wolffiana, correspond with and act like the kidneys 
of mature fishes. 13 Even at a later embryonic period, 
some striking resemblances between man and the lower 
animals may be observed. Bischoff says that the con- 
volutions of the brain in a human foetus at the end of 
the seventh month reach about the same stage of deve- 
lopment as in a baboon when adult. 14 The great toe, as 
Prof. Owen remarks, 15 " which forms the fulcrum when 
" standing or walking, is perhaps the most characteristic 



11 The human emhryo (upper fig.) 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, ' Entwicklungsgesckichte des Hunde-Eies,' 1845, tab. xi. fig. 
42 b. This drawing is five times magnified, the embryo being 25 days 
old. The internal viscera have been omitted, and the uterine appen- 
dages 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 ' Schopfungsgeschichte.' 

12 Prof. Wyman in ' Proc. of American Acad, of Sciences,' vol. iv. 
I860, p. 17. ' 

13 Owen, ' Anatomy of Vertebrates,' vol. i. p. 533. 

14 'Die Grosshimwindungen des Menschen,' 1868, s. 95. 

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



Chap. I. RUDIMENTS. 17 

" peculiarity in the human structure ; " but in an em- 
bryo, about an inch in length, Prof. Wyman 16 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, 17 who after asking, does man originate in a 
different way from a dog, bird, frog or fish ? says, " the 
" reply is uot doubtful for a moment; without question, 
" the mode of origin and the early stages of the develop- 
" ment 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." 

Budiments. — This subject, though not intrinsically 
more important than the two last, will for several rea- 
sons be here treated with more fullness. 18 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 distinguished from those that are nascent ; though 
in some cases the distinction is not easy. The former 
are either absolutely useless, such as the mammae 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 cannot 
suppose that they were developed under the conditions 



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

17 ' Man's Place in Nature,' p. G5. 

18 I had written a rough copy of this chapter before reading a valu- 
able paper, " Caratteri rudimc ntali in ordine all' origine del uoino " 
(' Annuario della Soc. d. Nat.,' Modena, 1867, p. 81), by G. Canestrini. 
to which paper I am considerably indebted. H'ackel has given admi- 
rable discussions on this whole subject, under the title of Dysteleology, 
in his ' Generelle Morphologie' and ' Schopfungsgeschichte.' 

VOL. 1. C 



18 THE DESCENT OF MAN. Part I. 

which now exist. Organs in this latter state are not 
strictly rudimentary, but they are tending in this direc- 
tion. Nascent organs, on the other hand, though not 
fully developed, are of high service to their possessors, 
and are capable of further development. Kudimentary 
organs are eminently variable; and this is partly in- 
telligible, as they are useless or nearly useless, and 
consequently are no longer subjected to natural selec- 
tion. They often become wholly suppressed. When 
this occurs, they are nevertheless liable to occasional 
reappearance through reversion ; and this is a circum- 
stance well worthy of attention. 

Disuse at that period of life, when an organ is chiefly 
used, and this is generally during maturity, together 
with inheritance at a corresponding period of life, seem 
to have been the chief agents in causing organs to be- 
come rudimentary. The term " disuse " does not relate 
merely to the lessened action of muscles, but includes 
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. Rudi- 
ments, however, may occur in one sex of parts normally 
present in the other sex ; and such rudiments, as we 
shall hereafter see, have often originated in a distinct 
manner. In some cases organs have been reduced by 
means of natural selection, from having become inju- 
rious 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 savins: 
to be effected by the economy of growth would be very 
small, 19 are difficult to understand. The final and com- 



19 Some good criticisms on this subject have been given by Messrs. 
Murie and Mivart, in < Transact. Zoolug. Soc' 1869, vol. vii. p. 92. 



Chap. I. RUDIMENTS. 19 

plete suppression of a part, already useless and much 
reduced in size, in which case neither compensation nor 
economy can come into play, is perhaps intelligible by 
the aid of the hypothesis of pangenesis, and apparently in 
no other way. But as the whole subject of rudimentary 
organs has been fully discussed and illustrated in my 
former works, 20 1 need here say no more on this head. 

Eudiments of various muscles have been observed in 
many parts of the human body ; 21 and not a few muscles, 
which are regularly present in some of the lower ani- 
mals 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, on the forehead, by which the 
eyebrows are raised. The platysma myoides, which is 
well developed on the neck, belongs to this system, but 
cannot be voluntarily brought into action. Prof. 
Turner, of Edinburgh, has occasionally detected, as he 
informs me, muscular fasciculi in five different situa- 
tions, namely in the axillae, near the scapulae, &c, all of 
which must be referred to the system of the panniculus. 
He has also shewn 22 that the musculus sternalis or ster- 
nalis brutorum, which is not an extension of the rectus 
abdominal is, but is closely allied to the panniculus, oc- 



20 ' Variation of Animals and Plants under Domestication,' vol. ii. 
pp. 317 and 397. See also 'Origin of Species,' 5th edit. p. 535. 

21 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 
" infiniment 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. 

22 Prof. W. Turner, ' Proc. Ptoyal Soc. Edinburgh,' 18GG-G7, p. Q5. 

c 2 



20 THE DESCENT OF MAN. Part I. 

curred in the proportion of about 3 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 arrangement." 

Some few persons have the power of contracting the 
superficial muscles on their scalps ; and these muscles 
are in a variable and partially rudimentary condition. 
M. A. de Candolle has communicated to me a curious 
instance of the long-continued persistence or inheritance 
of this power, as well as of its unusual development. 
He knows a family, in which one member, the present 
head of a 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, grandfather, and all his three chil- 
dren possess the same power to the same unusual degree. 
This family became divided eight generations ago into 
two branches ; so that the head of the above-mentioned 
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 persistently an 
absolutely useless faculty may be transmitted. 

The extrinsic muscles which serve to move the whole 
external ear, and the intrinsic muscles which move the 
different parts, all of which belong to the system of the 
panniculus, are in a rudimentary condition in man ; they 
are also variable in development, or at least in function. 
I have seen one man who could draw his ears for- 
wards, and another who could draw them backwards; 23 



23 Cabestrini quotes Hyrt. (' Annuario del]a Soc. dei Naturalisti,' 
Modena, 1807, p. 97) to the same effect. 



Chap. I. KUDIMENTS. 21 

and from what one of these persons told ine, it is pro- 
bable that most of us by often touching our ears and 
thus directing our attention towards them, could by 
repeated trials recover some power of movement. The 
faculty of erecting the ears and of directing them to 
different points of the compass, is no doubt of the 
highest service to many animals, as they thus perceive 
the point of danger ; but I have never heard of a man 
who possessed the least power of erecting his ears, — 
the one movement which might be of use to him. The 
whole external shell of the ear may be considered a 
rudiment, together with the various folds and promi- 
nences (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, 24 after collecting all the 
known evidence on this head, concludes that the exter- 
nal shell is of no distinct use. The ears of the chim- 
panzee and orang are curiously like those of man, and I 
am assured by the keepers in the Zoological Gardens 
that these animals never move or erect them ; so that 
they are in an equally rudimentary condition, as far as 
function is concerned, as in man. Why these animals, 
as well as the progenitors of man, should have lost the 
power of erecting their ears we cannot say. It may be, 
though I am not quite 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 b e a 
parallel case with that of those large and heavy^bffls,y^7^s 

The Diseases of the Ear,' by J. Toynbee, F.K.S., lwgph* 2 .^ *"»- <* 

H LIBRARY 



24 i 



22 



THE DESCENT OF MAN. 



PaPwT I. 



which from inhabiting oceanic islands have not been 
exposed to the attacks of beasts of prey, and have con- 
sequently lost the power of using their wings for flight. 
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 signification. 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 
subsequently more carefully those of man. The pecu- 
liarity consists in a little blunt point, projecting from 
the inwardly folded margin, or helix. Mr. Woolner 
made an exact model of one such case, and has sent 

me the accompanying drawing. 
(Fig. 2.) These points not only 
project inwards, but often a little 
outwards, so that they are visible 
when the head is viewed from di- 
rectly in front or behind. They 
are variable in size and some- 
what in position, standing either 
a little higher or lower ; and they 
sometimes occur on one ear and 
not on the other. Now the mean- 
ing of these projections is not, 
I think, doubtful; but it may 
be thought that they offer too 
trifling a character to be worth notice. This thought, 
however, is as false as it is natural. Every character, 
however slight, must be the result of some definite 
cause ; and if it occurs in many individuals deserves 
consideration. The helix obviously consists of the ex- 
treme margin of the ear folded inwards ; and this fold- 
ing appears to be in some manner connected with the 




Fig. 2. Human Ear, modelled 
and drawn by Mr. Woolner. 

a. The projecting point. 



Chap. I. RUDIMENTS. 23 

whole external ear being permanently pressed back- 
wards. In many monkeys, which do not stand high in 
the order, as baboons and some species of macacus, 23 the 
upper portion of t^e 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 and probably a little outwards. This 
could actually be observed in a specimen of the Ateles 
beelzebuth in the Zoological Gardens ; and we may safely 
conclude that it is a similar structure — a vestige of 
formerly pointed ears — which occasionally reappears in 
man. 

The nictitating membrane, or third eyelid, with its 
accessory muscles and other structures, is especially 
well developed in birds, and is of much functional im- 
portance to them, as it can be rapidly drawn across the 
whole eye-ball. It is found in some reptiles and amphi- 
bians, 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 marsu- 
pials, and in some few of the higher mammals, as in the 
walrus. But in man, the quadrumana, and most other 
mammals, it exists, as is admitted by all anatomists, as 
a mere rudiment, called the semilunar fold. 26 

The sense of smell is of the highest importance to 
the greater number of mammals — to some, as the rumi- 
nants, in warning them of danger ; to others, as the 



85 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. 

26 Muller's ' Elements of Physiology/ Eng. translat., 1842, vol. ii. p. 
1117. Owen, 'Anatomy of Vertebrates,' vol. iii. p. 2G0 ; ibid, on the 
Walrus, ' Proc. Zoolog. Soc.' November 8th, 1854. See also E. Knox, 
• Great Artists and Anatomists,' p. 10G. This rudiment apparently is 
somewhat larger in Negroes and Australians than in Europeans, see Carl 
Vogt, 4 Lectures on Man,' Eng. translat. p. 129. 



24 THE DESCENT OF MAN. Paht I. 

carnivora, in finding their prey ; to others, as the wild 
boar, for both purposes combined. But the sense of 
smell is of extremely slight service, if any, even to 
savages, in whom it is generally more highly developed 
than in the civilised races. It does not warn them of 
danger, nor guide them to their food ; nor does it pre- 
vent the Esquimaux from sleeping in the most fetid 
atmosphere, nor many savages from eating half-putrid 
meat. Those who believe in the principle of gradual 
evolution, will not readily admit that this sense in its 
present state was originally acquired by man, as he 
now exists. No doubt he inherits the power in an 
enfeebled and so far rudimentary condition, from some 
early progenitor, to whom it was highly serviceable 
and by whom it was continually used. We can thus 
perhaps understand how it is, as Dr. Maudsley has truly 
remarked, 27 that the sense of smell in man " is singu- 
" larly effective in recalling vividly the ideas and images 
'•' of forgotten scenes and places ;" for we see in those 
animals, which have this sense highly developed, such as 
dogs and horses, that old recollections of persons and 
places are strongly associated with their odour. 

Man differs conspicuously from all the other Primates 
in being almost naked. But a few short straggling 
hairs are found over the greater part of the body in 
the male sex, and fine down on that of the female sex. 
In individuals belonging to the same race these hairs 
are highly variable, not only in abundance, but like- 
wise in position : thus the shoulders in some Europeans 
are quite naked, whilst in others they bear thick tufts 
of hair. 28 There can be little doubt that the hairs 



27 'The Physiology and Pathology of Mind,' 2nd edit. 1S6S, p. 134. 

2S Eschricht, Ueber die Richtung der Haare am menschlicben Korper, 
' Miiller s Archiv fur Anat. und Phys.' 1837, s. 47. I shall often have 
to refer to this very curious paper. 



Chap I. KUDIMENTS. 25 

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-coloured hairs on the limbs and 
other parts of the body occasionally become developed 
into " thickset, long, and rather coarse dark hairs," 
when abnormally nourished near old-standing inflamed 
surfaces. 29 

I am informed by Mr. Paget that persons belonging 
to the same family often have a few hairs in their eye- 
brows much longer than the others ; so that this slight 
peculiarity seems to be inherited. These hairs appa- 
rently represent the vibrissa?, which are used as organs 
of touch by many of the lower animals. In a young 
chimpanzee I observed that a few upright, rather long, 
hairs, projected above the eyes, where the true eyebrows, 
if present, would have stood. 

The tine 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 moustache of this kind 
was observed by Eschricht 30 on a female foetus ; but this 
is not so surprising a circumstance as it may at first ap- 
pear, for the two sexes generally resemble each other in 
all external characters during an early period of growth. 
The direction and arrangement 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 



29 Paget, ' Lectures on Surgical Pathology,' 1S53, vol. i. p. 71. 

30 Eschricht, ibid. s. 40, 47. 



26 THE DESCENT OP MAN. Part I. 

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 coinci- 
dence, we must consider the woolly covering of the 
foetus to be the ruclimental representative of the first 
permanent coat of hair in those mammals which are 
born hairy. This representation is much more com- 
plete, in accordance with the usual law of embryological 
development, than that afforded by the straggling hairs 
on the body of the adult. 

It appears as if the posterior molar or wisdom-teeth 
were tending to become rudimentary in the more civi- 
lised races of man. These teeth are rather smaller 
than the other molars, as is likewise 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 dentists. They are also much more 
liable to vary both in structure and in the period of 
their development than the other teeth. 31 In the 
Melanian races, on the other hand, the wisdom-teeth 
are usually furnished with three separate fangs, and 
are generally sound : they also differ from the other 
molars in size less than in the Caucasian races. 32 Prof. 
Schaaffhausen accounts for this difference between the 
races by " the posterior dental portion of the jaw being 
" always shortened " in those that are civilised, 33 and this 
shortening may, 1 presume, be safely attributed to civi- 



S1 Dr. Webb, ' Teeth in Man and the Anthropoid Apes,' as quoted by 
Dr. C. Carter Blake in ' Anthropological Keview,' July, 1867, p. 299. 

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

33 ' On the Primitive Form of the Skull,' Eng. translat. in ' Anthro- 
pological Keview,' Oct. 1868, p. 426. 



Chap. I. EUDIMENTS. 27 

lised 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 practice 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 account of only a single rudiment, namely the 
vermiform appendage of the caBcum. The ca3cum is 
a branch or diverticulum of the intestine, ending in a 
cul-de-sac, and it is extremely long in many of the 
lower vegetable-feeding mammals. In the marsupial 
koala it is actually more than thrice as long as the 
whole body. 34 It is sometimes produced into a long 
gradually-tapering point, and is sometimes 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 rudiment of the shortened part. That this ap- 
pendage is a rudiment, we may infer from its small 
size, and from the evidence which Prof. Canestrini 35 has 
collected of its variability in man. It is occasionally 
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 flat- 
tened solid expansion. In the orang this appendage is 
long and convoluted : in man it arises from the end of 
the short caecuni, 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 some- 
times the cause of death, of which fact I have lately 
heard two instances : this is due to small hard bodies, 



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

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



28 THE DESCENT OF MAN. Part I. 

such as seeds, entering the passage and causing inflam- 
mation. 36 

In the Quadrumana and some other orders of mam- 
mals, especially in the Carnivora, there is a passage near 
the lower end of the humerus, called the supra-condyloid 
foramen, through which the great nerve of the fore limb 
passes, and often the great artery. Now in the humerus 
of man, as Dr. Struthers 37 and others have shewn, there 
is generally a trace of this passage, and it is sometimes 
fairly well developed, being formed by a depending 
hook-like process of bone, completed by a band of 
ligament. When present the great nerve invariably 
passes through it, and this clearly indicates that it is the 
liomologue and rudiment of the supra-condyloid fora- 
men of the lower animals. Prof. Turner estimates, as 
he informs me, that it occurs in about one per cent, of 
recent skeletons. 

There is another foramen in the humerus, which 
may be called the inter-condyloid ; and this occurs in 
various genera of anthropoid and other apes, 38 and occa- 
sionallv in man. It is remarkable that this foramen 
seems to have been much more frequently present 
during ancient than during recent times. Mr. Busk 39 
has collected the following evidence on this head : Prof. 
Broca "noticed the perforation in four and a half per 
" cent, of the arm-bones collected in the ' Cimetiere du 



36 M. C. Martins ("De l'Unite Organique," in 'Kevuo des Deux 
Mondes,' June 15, 1862, p. 16), and H'ackel ('Generelle Morphologie,' 
B. ii. s. 278), have both remarked on the singular fact of this rudiment 
sometimes causing death. 

37 ' The Lancet,' Jan. 24, 18G3, p. 83. Dr. Knox, ' Great Artists and 
Anatomists,' p. 63. See also an important memoir on this process by 
Dr. Grube, in the ' Bulletin de l'Acad. Imp. de St. Pe'tersbourg,' torn. 
xii. 1867, p. 448. 

38 Mr. St. George Mivart, ' Transact. Phil. Soc' 18 .7, p. 310. 

39 " On the Caves of Gibraltar," ' Transact. Intermit. Congress of 
Prehist. Arch.' Third Session, 1869, p. 159. 



Chap. I. KUDIMENTS. 29 

" Sud ' at Paris ; and in the Grotto of Orrony, the con- 
11 tents of which are referred to the Bronze period, as 
" many as eight humeri out of thirty-two were perfo- 
" rated ; but this extraordinary proportion, he thinks, 
" might be due to the cavern having been a sort of 
" ' family vault.' Again, M. Dupont found 30 per cent. 
" of perforated bones in the caves of the Valley of the 
" Lesse, belonging to the Keindeer period ; whilst M. 
"• Leguay, in a sort of dolmen at Argentenil, 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 unno- 
" ticed that M. Prnner-Bey states that this condition is 
" common in Guanche skeletons." The 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 races, is interesting. One 
chief cause seems to be that ancient races stand some- 
what nearer than modern races in the long line of 
descent to their remote animal-like progenitors. 

The os coccyx in man, though functionless as a tail, 
plainly represents this part in other vertebrate animals. 
At an early embryonic period it is free, and, as we have 
seen, projects beyond the lower extremities. In certain 
rare and anomalous cases it has been known, according 
to Isidore Geoffroy St.-Hilaire and others, 40 to form a 
small external rudiment of a tail. The os coccyx is 
short, usually including only four vertebrae : and these 
are in a rudimental condition, for they consist, with the 
exception of the basal one, of the centrum alone. 41 They 
are furnished with some small muscles ; one of which, as 
I am informed by Prof. Turner, has been expressly 
described by Theile as a rudimentary repetition of the 



40 Quatrefages lias lately collected the evidence on this subject. 
'Kevue des Cours h-'cientifiques/ 1867-1868, p. 625. 



41 



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



30 THE DESCENT OF MAN. Part I. 

extensor of the tail, which is so largely developed in 
many mammals. 

The spinal cord in man extends only as far down- 
wards as the last dorsal or first lumbar vertebra ; but a 
thread-like structure (the filum terminate) 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 
undoubtedly homologous with the spinal cord ; but the 
lower part apparently 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 im- 
portant 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, shews how 
closely the os coccyx corresponds with the true tail in 
the lower animals: Luschka has recently discovered at 
the extremity of the coccygeal bones a very peculiar 
convoluted bodv, which is continuous with the middle 
sacral artery ; and this discovery led Krause and Meyer 
to examine the tail of a monkey (Macacus) and of a cat, 
in both of which they found, though not at the extre- 
mity, a similarly convoluted body. 

The reproductive system offers various rudimentary 
structures ; but these differ in one important respect 
from the foregoing cases. We are not here concerned 
with a vestige of a part which does not belong to the 
species in an efficient state; but with a part which 
is always present and efficient in the one sex, being 
represented in the other by a mere rudiment. Never- 
theless, the occurrence of such rudiments is as diffi- 
cult to explain on the belief of the sejmrate creation 
of each species, as in the foregoing cases. Hereafter 
I shall have to recur to these rudiments, and shall 
shew that their presence generally depends merely on 
inheritance ; namely, on parts acquired by one sex 



Chap. I. THE DESCENT OF MAX. 31 

having been partially transmitted to the other. Here 
I will onlv srive some instances of such rudiments. It 
is well known that in the males of all mammals, in- 
cluding man, rudimentary mammae exist. These in 
several instances have become well developed, and have 
yielded a copious supply of milk. Their essential iden- 
tity in the two sexes is likewise shewn by their occa- 
sional sympathetic enlargement in both during an 
attack of the measles. The vesicula prostatica, which 
has been observed in manv male mammals, is now uni- 
versally 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 bifur- 
cates, for in the males of these the vesicula likewise 
bifurcates. 42 Some additional rudimentary structures 
belonging to the reproductive system might here have 
been adduced. 43 

The bearing of the three great classes of facts now 
given is unmistakeable. But it would be superfluous here 
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 simi- 
larity of pattern between the hand of a man or monkey, 
the foot of a horse, the flipper of a seal, the wing of 



42 Lenckart, 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 a^ well 
as in other characters. 

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



32 THE DESCENT OF MAX. Part I. 

a bat, &c., is utterly inexplicable. It is no scientific 
explanation to assert that they 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 marvellous fact that the embryo 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 selection of those 
individuals which were least encumbered with a super- 
fluous part, aided by the other means previously indi- 
cated. 

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 consider the evidence de- 
rived from their affinities or classification, their geo- 
graphical 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 



Chap. I. 



THE DESCENT OF MAN. 



33 



this conclusion. But the time will before long come 
when it will be thought wonderful, that naturalists, who 
were well acquainted with the comparative structure 
and development of man and other mammals, should 
have believed that each was the work of a separate act 
of creation. 




VOL. I. 



D 



S± THE DESCENT OF MAN. Part T. 



CHAPTEK II. 

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 — Ima- 
gination — Reason — Progressive improvement — Tools and 
weapons used by animals — Language — Self-consciousness — 
Sense of beauty — Belief in God, spiritual agencies, superstitions. 

We have seen in the last chapter 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 com- 
pare the mind of one of the lowest savages, who has no 
words to express any number higher than four, and who 
uses no abstract terms for the commonest objects or 
affections, 1 with that of the most highly organised ape. 
The difference would, no doubt, still remain immense, 
even if one of the higher apes had been improved or 
civilised as much as a dog has been in comparison with 
its parent-form, the wolf or jackal. The Fuegians 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 disposition and in most of our mental faculties. If no 



1 See the evidence on these points, as given by Lubbock, ' Prehistoric 
Times,' p. 354, &c. 



Chap. II. MENTAL POWEES. 35 

organic being excepting man had possessed any mental 
power, or if his powers had been of a wholly different 
nature from those of the lower animals, then we should 
never have been able to convince ourselves that our 
high faculties had been gradually developed. But it 
can be clearly shewn that there is no fundamental 
difference of this kind. We must also admit that 
there is a much wider interval in mental power be- 
tween one of the lowest fishes, as a lamprey or lancelet, 
and one of the higher apes, than between an ape and 
man ; yet this immense interval is filled up by number- 
less 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 does 
not use 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 solely to shew that there 
is no fundamental difference between man and the 
higher mammals in their mental faculties. Each divi- 
sion 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 univer- 
sally accepted, I shall arrange my remarks in the order 
most convenient for my purpose ; and will select those 
facts which have most struck me, with the hope that 
they may produce some effect on the reader. 

With respect to animals very low in the scale, I shall 
have to give some additional facts under Sexual Selec- 
tion, shewing that their mental powers are higher than 

d 2 



36 THE DESCENT OF MAN. Part I. 

might have been expected. The variability of the facul- 
ties in the individuals of the same species is an im- 
portant 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 
enquiry, that it is the unanimous opinion of all those 
who have long attended to animals of many kinds, 
including birds, that the individuals differ greatly in 
everv mental characteristic. In what manner the mental 

at 

pow r ers were first developed in the lowest organisms, 
is as hopeless an enquiry as how life first originated. 
These are problems for the distant future, if they are 
ever to be solved bv man. 

As man possesses the same senses with 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 power possessed by the 
latter of sucking, and so forth. But man, perhaps, has 
somewhat fewer instincts than those possessed by the 
animals 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, and man has no such knowledge ; but as our 
domestic animals, when 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 



Chap. II. MENTAL POWERS. 37 

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 con- 
trast with those of the lower animals. Cuvier main- 
tained 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 Pouch et, 
in an interesting essay, 2 has shewn 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 re- 
markable for its instincts, namely the beaver, is highly 
intelligent, as will be admitted by every one who has 
read Mr. Morgan's excellent account of this animal. 3 

Although the first dawnings of intelligence, accord- 
ing to Mr. Herbert Spencer, 4 have been developed 
through the multiplication and co-ordination of reflex 
actions, and although many of the simpler instincts 
graduate into actions of this kind 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, how- 
ever, far from wishing to deny that instinctive actions 
may lose their fixed and untaught character, and be 
replaced by others performed by the aid of the free will. 
On the other hand, some intelligent actions — as when 
birds on oceanic islands first learn to avoid man — after 



2 ' L'Instinct chez les Insectes.' ' Eevue des Deux Mondes,' Feb. 
1870, p. 690. 

3 ' The American Beaver and his Works,' 1868. 

4 ' The Principles of Psychology/ 2nd edit. 1870, pp. 418-443 



38 THE DESCENT OF MAN. Part I. 

being performed during many generations, become con- 
verted into instincts and are inherited. They 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 man- 
ner, through the natural selection of variations of simpler 
instinctive actions. Such variations appear to arise from 
the same unknown causes acting on the cerebral organ- 
isation, which induce slight variations or individual dif- 
ferences in other parts of the body ; and these variations, 
owing to our ignorance, are often said to arise sponta- 
neously. We can, I think, come to no other conclusion 
with respect to the origin of the more complex instincts, 
when we reflect on the marvellous instincts of sterile 
worker-ants and bees, which leave no offspring to inherit 
the effects of experience and of modified habits. 

Although a high degree of intelligence is certainly 
compatible with the existence of complex instincts, as 
we see in the insects just named and in the beaver, it is 
not improbable that they may to a certain extent inter- 
fere with each other's development. Little is known 
about the functions of the brain, but we can perceive 
that as the intellectual powers become highly developed, 
the various parts of the brain must be connected by the 
most intricate channels of intercommunication ; and as 
a consequence each separate part would perhaps tend to 
become less well fitted to answer in a definite and uni- 
form, that is instinctive, manner to particular sensations 
or associations. 

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 com- 
pare their actions founded on the memory of past 
events, on foresight, reason, and imagination, with 



Chap. II. MENTAL POWEES. 39 

exactly similar actions instinctively performed by the 
lower animals ; in this latter case the capacity of 
performing such actions having 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 genera- 
tion. No doubt, as Mr. Wallace has argued, 5 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, 
make, 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, 
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 exhi- 
bited 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, 6 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 pal- 
pitate, the sphincters to be relaxed, and the hair to 
stand on end. Suspicion, the offspring of fear, is emi- 
nentlv characteristic of most wild animals. Courage 



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

6 ' Kecherches sur les Mceurs des Foumris,' 1810, p. 173. 



40 THE DESCENT OF MAN. Part I. 

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 certainly inherited. Every one 
knows how liable animals are to furious rage, and how 
plainly they show it. Many anecdotes, probably true, 
have been published on the long-delayed and artful 
revenge of various animals. The accurate Kengger and 
Brehm 7 state that the American and African monkeys 
which they kept tame, certainly revenged themselves. 
The love of a dog for his master is notorious ; in the 
agony of death he has been known to caress his master, 
and every one has heard of the dog suffering under 
vivisection, who licked the hand of the operator ; this 
man, unless he had a heart of stone, must have felt 
remorse to the last hour of his life. As Whewell 8 has 
remarked, "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 maternal affection exhibited in the most 
trifling details ; thus Kengger 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 cer- 
tain kinds kept under confinement by Brehm in N. 



~> All the following statements, given on tlie authority of these two 
naturalists, are taken from Kengger's ' Naturges. der Saugethiere 
von Paraguay,' 1830, s. 41 -57, and from Brehm's ' Thierleben,' B. i. 
s. 10-87. ' 

8 ' Bridgewater Treatise,' p. 263. 



Chap. II. MENTAL POWERS. 41 

Africa. Orphan- monkeys were always adopted and 
careful] y guarded by the other monkeys, 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 the above- 
mentioned 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, 1 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 rela- 
tives, 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 will also, according to Brehm, defend their 
master when attacked by any one, as well as dogs to 
whom thev are attached, from the attacks of other 
dogs. But we here trench on the subject of sympathy, 
to which I shall recur. Some of Brehm 's monkeys 
took much delight in teasing, in various ingenious 
ways, a certain old dog whom they disliked, as well 
as other animals. 

Most of the more complex emotions are common to 
the higher animals and ourselves. Every one has seen 



42 THE DESCENT OF MAN. Part I. 

how jealous a dog is of his master's affection, if lavished 
on any other creature ; and I have observed the same fact 
with monkeys. This shews that animals not only love, 
but have the desire to be loved. Animals manifestly 
feel emulation. They love approbation or praise ; and 
a clog 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 something 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 offences. 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. 

We will now turn to the more intellectual emotions 
and faculties, which are very important, as forming the 
basis for the development 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 have 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 
towards 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 



Chap. II. MENTAL POWERS. 43 

coiled-up snake into the monkey-house at the Zoo- 
logical Gardens, and the excitement thus caused was 
one of the most curious spectacles which 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 understood 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 compartments. After a time all the monkeys 
collected round it in a large circle, and staring in- 
tently, presented a most ludicrous appearance. They 
became extremely nervous ; so that when a wooden ball, 
with which they were familiar as a plaything, was acci- 
dently 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, and 
some 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 immediately 
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 momentary peeps into the upright bag, 
at the dreadful object lying quiet at the bottom. It 
would almost appear as if monkeys had some notion of 
zoological affinities, for those kept by Brehm exhibited 
a strange, though mistaken, instinctive dread of inno- 
cent lizards and frogs. An orang, also, has been known 
to be much alarmed at the first sight of a turtle. 9 



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



44 THE DESCENT OF MAN. Part I. 

The principle of Imitation is strong in man, and 
especially in man in a barbarous state. Desor 10 has 
remarked that no animal voluntarily 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 
others' actions : thus two species of wolves, which had 
been reared by dogs, learned to bark, as does some- 
times the jackal, 11 but whether this can be called volun- 
tary imitation is another question. From one account 
which I have read, there is reason to believe that puppies 
nursed by cats sometimes learn to lick their feet and 
thus to clean their faces : it is at least certain, as I hear 
from a perfectly trustworthy friend, that some dogs 
behave in this manner. Birds imitate the songs of their 
parents, and sometimes those of other birds ; and par- 
rots are notorious imitators of any sound which they 
often hear. 

Hardly any faculty is more important for the intel- 
lectual progress of man than the power of 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 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 so soon learn whether 



10 Quoted by Vogt, ' Memoire sur les Microce'pkales,' 1867, p. 168. 

11 ' The Variation of Animals and Plants under Domestication,' vol. 
i. p. 27. 



Chap. II. MENTAL POWERS. 45 

a particular monkey would turn out a good actor, he 
answered that it all depended on their power of atten- 
tion. 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 in- 
attentive monkey act, it turned sulky. On the 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, recognised 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 in- 
stantly followed me out walking 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 12 has clearly shewn, 
recognised their fellow-ants belonging to the same com- 
munity 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, independently of 
the will, former images and ideas, and thus creates bril- 
liant and novel results. A poet, as Jean Paul Richter 
remarks, 13 " who must reflect whether he shall make a 



12 'Les Moeurs des Fourmis,' 1810, p. 150. 

13 Quoted in Dr. Maudsley's ' Physiology and Pathology of Mind,' 
186S, pp. 19, 220. 



46 THE DESCENT OF MAN. Part I. 

" 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 involuntary 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 selecting 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, as is stated on good authority, 14 have vivid dreams, 
and this is shewn by their movements and voice, we must 
admit that they possess some power of imagination. 

Of all the faculties of the human mind, it will, I 
presume, be admitted that Beason stands at the summit. 
Few persons any longer 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 unlearnt instincts. 15 In future 
chapters we shall see that some animals extremely low in 
the scale apparently display a certain amount of reason. 
No doubt it is often difficult to distinguish between the 
power of reason and that of instinct. Thus Dr. Hayes, 
in his work on * The Open Polar Sea,' repeatedly re- 
marks that his dogs, instead of continuing to draw the 
sledges in a compact body, diverged and separated when 
they came to thin ice, so that their weight might be 
more evenly distributed. This was often the first warn- 



14 Dr. Jerdon, ' Birds of India,' vol. i. 1862, p. xxi. 

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



Chap. II. MENTAL POWEES. 47 

ing and notice which the travellers 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 an instinct ? This instinct 
might possibly have arisen since the time, long ago, 
when dogs were first employed by the natives in draw- 
ing their sledges ; or the Arctic wolves, the parent-stock 
of the Esquimaux dog, may have acquired this instinct, 
impelling them not to attack their prey in a close pack 
when on thin ice. Questions of this kind are most 
difficult to answer. 

So many facts have been recorded in various works 
shewing that animals possess some degree of reason, 
that I will here give only two or three instances, authen- 
ticated by Kengger, and relating to American monkeys, 
which stand low in their order. He states that when 
he first gave eggs to his monkeys, they smashed them 
and thus lost much of their contents ; afterwards thev 
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 
care. Lumps of sugar were often given them wrapped 
up in paper ; and Eengger sometimes put a live wasp 
in the paper, so that in hastily unfolding it they got 
stung ; after this had once happened, they always first 
held the packet to their ears to detect any movement 
within. Any one who is not convinced by such facts as 
these, and by what he may observe with his own dogs, 
that animals can reason, would not be convinced by 
anything that I could add. Nevertheless I will give 
one case with respect to dogs, as it rests on two distinct 
observers, and can hardly depend on the modification 
of any instinct. 



48 THE DESCENT OF MAN. Part I. 

Mr. Colquhoun 16 winged two wild-ducks, which fell 
on the opposite side of a stream ; his retriever tried to 
bring over both at once, but could not succeed ; she 
then, though never before known to ruffle a feather, 
deliberately killed one, brought over the other, and re- 
turned 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 not 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 in- 
" stance of her ever having wilfully 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. 

The muleteers in S. America say, "I will not give 
" you the mule whose step is easiest, but la mas rational, 
" — the one that reasons best ; ,: and Humboldt 17 adds, 
"this popular expression, dictated by long experience, 
" combats the system of animated machines, better per- 
" haps than all the arguments of speculative j)hilosophy." 

It has, I think, now been shewn that man and the 
higher animals, especially the Primates, have some few 
instincts in common. All have the same senses, intui- 
tions and sensations — similar passions, affections, and 
emotions, even the more complex ones ; they feel 

16 'The Moor and the Loch,' p. 45. Col. Hutchinson on ' Dog 
Breaking,' 1850, p. 46. 

17 'Personal Narrative,' Eng. translat., vol. iii. p. 106. 



Chap. II. MENTAL POWERS. 49 

wonder and curiosity ; they possess the same faculties 
of imitation, attention, memory, imagination, and reason, 
though in very different degrees. Nevertheless many 
authors have insisted that man is separated through his 
mental faculties by an impassable barrier from all the 
lower animals. I formerly made a collection of above 
a score of such aphorisms, but they are not worth 
giving, 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 progres- 
sive improvement ; that he alone makes use of tools or 
fire, domesticates other animals, possesses property, or 
employs language ; that no other animal is self-con- 
scious, comprehends itself, has the power of abstraction, 
or possesses general ideas ; that man alone has a sense 
of beauty, is liable to caprice, has the feeling of grati- 
tude, mystery, &c. ; believes in God, or is endowed with 
a conscience. I will hazard a few remarks on the more 
important and interesting of these points. 

Archbishop Sumner formerly maintained 18 that man 
alone is capable of progressive improvement. 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 improbable that all should have 
partaken of the poison, and impossible that all should 
have been caught in the trap. They must learn caution 
by seeing their brethren caught or poisoned. In North 
America, where the fur-bearing animals have long been 



18 Quoted by Sir C. Lyell, 'Antiquity of Man,' p. 497. 
VOL. I. E 



50 THE DESCENT OF MAN. Part I. 

pursued, they exhibit, according to the unanimous tes- 
timony of all observers, an almost incredible amount 
of sagacity, caution, and cunning ; but trapping has 
been there so long carried on that inheritance may have 
come into play. 

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 ; 19 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, 20 
states that in districts where foxes are much hunted, 
the vouno* when thev first leave their burrows are in- 
contestably much more wary than the old ones in dis- 
tricts where they are not much disturbed. 

Our domestic dogs are descended from wolves and 
jackals, 21 and though they may not have gained in 
cunning, and may have lost in waryness and suspicion, 
yet they have progressed in certain moral qualities, 
such as in affection, trust-worthiness, temper, and pro- 
bably in general intelligence. The common rat has 
conquered and beaten several other species through- 
out Europe, in parts of North America, New Zealand, 
and recently in Formosa, as well as on the mainland of 
China. Mr. Swinhoe, 22 who describes these latter cases, 
attributes the victory of the common rat over the large 
Mus coninga to its 'superior cunning; and this latter 
quality may be attributed to the habitual exercise of 
all its faculties in avoiding extirpation by man, as well 



19 ' Journal of Researches during the Voyage of the " Beagle," ' 184f>, 
p. 398. ' Origin of Species,' 5th edit. p. 260. 

20 ' Lettres Phil, sur l'lntelligence des Animaux,' nouvelle edit. 
1802, p. 86. 

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

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



Chap. II. MENTAL POWEKS. 51 

as to nearly all the less cunning or weak-minded rats 
having been successively destroyed by him. To main- 
tain, 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. Hereafter we shall see that, 
according to Lartet, existing mammals belonging to 
several orders have larger brains than their ancient 
tertiary prototypes. 

It lias often been said that no animal uses any tool ; 
but the chimpanzee in a state of nature cracks a native 
fruit, somewhat like a walnut, with a stone. 23 Bengger 24 
easily taught an American monkey thus to break open 
hard palm-nuts, and afterwards 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 flavour. Another monkey was taught 
to open the lid of a large box with a stick, and after- 
wards it used the stick as a lever to move heavv 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. In the cases just men- 
tioned stones and sticks were employed as implements ; 
but they are likewise used as weapons. Brehm 25 states, 
on the authority of the well-known traveller Schimper, 
that in Abyssinia when the baboons belonging to one 
species (C. gelada) descend in troops from the moun- 
tains to plunder the fields, they sometimes encounter 
troops of another species (C. hamadryas), and then a 
fight ensues. The Geladas roll down great stones, which 
the Hamadryas try to avoid, and then both species, 



23 Savage and Wyman in 'Boston Journal of Nat. Hist.' vol. iv. 
]f43-44, p. 383. 



24 ' Siiugethiere von Paraguay,' 1830, s. 51-56. 

25 ' Thierleben,' B. i. s. 79, 82. 



E 2 



52 THE DESCENT OF MAN. Pabt I. 

making a great uproar, rush furiously against each 
other. Brehm, when accompanying 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 for 
a time closed against tlie caravan. It deserves notice 
that these baboons thus acted in concert. Mr. Wal- 
lace 26 on three occasions saw female orangs, accom- 
panied 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." 

In the Zoological Gardens a monkev which had weak 
teeth used to break open nuts with a stone ; and I was 
assured by the keepers that this animal, after using the 
stone, hid it in the straw, and 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 27 remarks, that the fashioning of 
an implement for a special purpose is absolutely peculiar 
to man ; and he considers that this forms an immeasur- 
able gulf between him and the brutes. It is no doubt 
a very important distinction, but there appears to me 
much truth in Sir J. Lubbock's suggestion, 28 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 intentionally break the 



26 ' The Malay Archipelago,' vol. i. 1869, p. 87. 

27 ' Primeval Man,' 1869, pp. 145, 147. 

28 ' Prehistoric Times,' 1865, p. 473, &c. 



Chap. II. MENTAL POWERS. 53 

flints, and not a very wide step to rudely fashion them. 
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 originated." The 
nature of fire would have been known in the many 
volcanic regions where lava occasionally flows through 
forests. 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 throwing a straw-mat over its head. In these 
latter habits, we probably see the first steps towards 
some of the simpler arts ; namely rude architecture 
and dress, as they arose amongst the early progenitors 
of man. 

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, Arch- 
bishop 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." 29 In Paraguay the Cebus azarse 
when excited utters at least six distinct sounds, which 



29 Quoted in ' Anthropological Review,' 18G4, p. 158. 



5-4 THE DESCENT OF MAN. Part I. 

excite in other monkeys similar emotions. 30 The move- 
ments of the features and gestures of monkeys are un- 
derstood by us, and they partly understand ours, as 
Eeno-o-er and others declare. It is a more remark- 

DO 

able fact that the dog, since being domesticated, has 
learnt to bark 31 in at least four or five distinct tones. 
Although barking is a new art, no doubt the wild spe- 
cies, the parents 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 ; the yelping or howling bark of despair, 
as when shut up ; that 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. 

Articulate language is, however, peculiar to man ; 
but he uses in common with the lower animals inarti- 
culate cries to express his meaning, aided by gestures 
and the movements of the muscles of the face. 32 This 
especially holds good with the more simple and vivid 
feelings, which are but little connected with our higher 
intelligence. Our cries of pain, fear, surprise, anger, to- 
gether with their appropriate actions, and the murmur 
of a mother to her beloved child, are more expressive 
than any words. It is not the mere power of articula- 
tion that distinguishes man from other animals, for as 
every one knows, parrots can talk ; but it is his large 
power of connecting definite sounds with definite ideas ; 
and this obviously depends on the development of the 
mental faculties. 



30 Kenggcr, ibid. s. 45. 

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

32 See a discussion on this subject in Mr. E. B. Tylor's very interest- 
ing work, 'Eesearches into the Early History of Mankind,' 1865, chaps, 
ii. to iv. 



Chap. II. MENTAL POWERS. 55 

As Home Tooke, 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 
much more appropriate simile. It certainly is not a 
true instinct, as 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 ; each has been slowly and 
unconsciously developed by many steps. The sounds 
uttered by birds offer in several respects the 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 that have the power 
of singing exert this power instinctively ; but the actual 
song, and even the call-notes, are learnt from their 
parents or foster-parents. These sounds, as Daines 
Barrington 33 has proved, " are no more innate than 
" language is in man." The first attempts to sing 
" may be compared to the imperfect endeavour in a 
" child to babble." The young males continue prac- 
tising, 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, teacli and 
transmit their new song to their offspring. The slight 
natural differences of song in the same species inha- 



33 Hon. Daines Barrington in ' Philosoph. Transactions,' 1773, p. 
262. See also Dureau de la Malle, in ' Ann. des Sc. Nat.' 3rd series, 
Zoolog. torn. x. p. 119. 



56 THE DESCENT OF MAN. Part I. 

biting different districts may be appositely compared, 
as Barrington remarks, " to provincial dialects ;" and 
the songs of allied, though distinct species may be com- 
pared with the languages of distinct races of man. I 
have given the foregoing details to shew that an in- 
stinctive tendency to acquire an art is not a peculiarity 
confined to man. 

With respect to the origin of articulate language, 
after having read on the one side the highly interesting 
works of Mr. Hensleigh Wedgwood, the Kev. F. Farrar, 
and Prof. Schleicher, 34 and the celebrated lectures of 
Prof. Max Miiller on the other side, I cannot doubt that 
language owes its origin to the imitation and mo- 
dification, aided by signs and gestures, of various 
natural sounds, the voices of other animals, and man's 
own instinctive cries. When we treat of sexual selec- 
tion we shall see that primeval man, or rather some 
early progenitor of man, probably used his voice largely, 
as does one of the gibbon-apes at the present day, in 
producing true musical cadences, that is in singing ; 
we may conclude from a widely -spread analogy that 
this power would have been especially exerted during 
the courtship of the sexes, serving to express various 
emotions, as love, jealousy, triumph, and serving as a 
challenge to their rivals. The imitation by articulate 
sounds of musical cries might have given rise to 
words expressive of various complex emotions. As 
bearing on the subject of imitation, the strong tendency 
in our nearest allies, the monkeys, in microcephalous 



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



Chap. II. MENTAL POWEES. 57 

idiots, 35 and in the barbarous races of mankind, to imi- 
tate whatever they hear deserves notice. As monkeys 
certainly understand much that is said to them by man, 
and as in a state of nature they utter signal-cries of 
danger to their fellows, 36 it does not appear altogether 
incredible, that some unusually wise ape-like animal 
should have thought of imitating the growl of a beast 
of prey, so as to indicate to his fellow monkeys the 
nature of the expected danger. And 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 pro- 
genitor 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 continued use and .advance- 
ment of this power would have reacted on the mind by 
enabling and encouraging it to carry on long trains of 
thought. A long and complex train of thought can no 
more be carried on wdthout the aid of words, whether 
spoken or silent, than a long calculation without the 
use of figures or algebra. It appears, also, that even 
ordinary trains of thought almost require some form of 
language, for the dumb, deaf, and^ blind girl, Laura 
Bridgman, was observed to use her fingers whilst dream- 



35 Vogt, 'Memoire sur les Microcephales,' 1867, p. 169. With 
respect to savages, I have given some facts in my ' Journal of 
Eesearches,' &c, 1845, p. 206. 

36 See clear evidence on this head in the two works so often quoted, 
by Brehm and Kengger. 



58 THE DESCENT OF MAN. Part I. 

ing. 37 Nevertheless a long succession of vivid and con- 
nected ideas, may pass through the mind without the 
aid of any form of language, as we may infer from the 
prolonged dreams of dogs. We have, also, seen that 
retriever-dogs are able to reason to a certain extent ; 
and this they manifestly do 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 
shewn by those curious cases of brain-disease, in which 
speech is specially affected, as when the power to re- 
member substantives is lost, whilst other words can be 
correctly used. 38 There is no more improbability in 
the effects of the continued use of the vocal and mental 
organs being inherited, than in the case of hand- 
writing, which depends partly on the structure of the 
hand and partly on the disposition of the mind ; and 
hand-writing is certainly inherited. 39 

Why the organs now used for speech should have 
been originally perfected for this purpose, rather than 
any other organs, it is not difficult to see. Ants have 
considerable powers of intercommunication by means 
of their antennae, as shewn by Huber, who devotes a 
whole chapter to their language. We might have used 
our fingers as efficient instruments, for a person w T ith 
practice can report to a deaf man every word of a speech 
rapidly delivered at a public meeting ; but the loss of 
our hands, whilst thus employed, would have been 
a serious inconvenience. As all the higher mammals 
possess vocal organs constructed on the same general 



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

38 Many curious cases have been recorded. See, for instance, 
' Inquiries Concerning the Intellectual Powers/ by Dr. Aberciombie, 
1838, p. 150. 

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



Chap. II. MENTAL POWERS. 59 

plan with ours, and which are used as a means of commu- 
nication, it was obviously probable, if the power of com- 
munication had to be improved, that these same organs 
would have been still further developed ; and this has 
been effected by the aid of adjoining and well-adapted 
parts, namely the tongue and lips. 40 The fact of the 
higher apes not using their vocal organs for speech, 1:0 
doubt depends on their intelligence not having been 
sufficiently advanced. 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 possess 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 merely for croaking. 41 

The formation of different languages and of dis- 
tinct species, and the proofs that both have been de- 
veloped through a gradual process, are curiously the 
same. 42 But we can trace the origin of many words 
further back than in the case of species, for we can 
perceive how they have actually arisen 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 



40 See some good remarks to this effect by Dr. Maudsley, ' The 
Physiology and Pathology of Mind,' 1868, p. 199. 

41 Macgillivray, 'Hist, of British Birds,' vol. ii. 1839, p. 29. An 
excellent observer, Mr. Blackwall, remarks that the magpie learns to 
pronounce single words, and even short sentences, more readily than 
ulmost 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. ' Kesearches in Zoology,' 
1834, p. 158. 

42 See the very interesting parallelism between the deveh 
species and languages, given by Sir C. Lyell in ' The GeoloafT J^v)«en^is ^ > ^ 
of the Antiquity of Man,' 1 803, chap, xxiii. /^ O < 

f£j i* ^*^ -5 

LIBRARY 




60 THE DESCENT OF MAN. Part I. 

formation. The manner in which certain letters or 
sounds change when others change is very like corre- 
lated growth. We have in both cases the reduplication 
of parts, the effects of long-continued use, aud so forth. 
The frequent presence of rudiments, both in languages 
and in species, is still more remarkable. The letter m 
in the word am, means I ; so that in the expression lam, 
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 beings, 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 lan- 
guage, like a species, when once extinct, never, as Sir 
C. Lyell remarks, reappears. The same language never 
has two birth-places. Distinct languages may be crossed 
or blended together. 43 We see variability in every 
tongue, and new words are continually cropping up ; but 
as there is a limit to the powers of the memory, single 
words, like whole languages, gradually become extinct. 
As Max Muller 44 has well remarked: — " A struggle for 
" life is constantly going on amongst the words and gram- 
"matical forms in each language. The better, the 
" shorter, the easier forms are constantly 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 may, I 
think, be added ; for there is in the mind of man a strong 
love for slight changes in all things. The survival or 



43 See remarks to this effect by the Rev. F. W. Farrar, in an interest- 
ing article, entitled " Philology and Darwinism " in ' Nature,' March 
24th, 1870, p. 528. 

44 ' Nature,' Jan. 6th, 1870, p. 257. 



Chap. II. MENTAL POWERS. Gl 

preservation of certain favoured words in the struggle 
for existence is natural selection. 

The perfectly regular and wonderfully complex con- 
struction of the languages of many barbarous nations 
has often been advanced as a proof, either of the divine 
origin of these languages, or of the high art and former 
civilisation of their founders. Thus F. von Schlegel 
writes : " In those languages which appear to be at the 
" lowest grade of intellectual culture, we frequently ob- 
" serve a very high and elaborate degree of art in their 
" grammatical structure. This is especially the case with 
" the Basque and the Lapponian, and many of the Ame- 
" rican languages." 45 But it is assuredly an error to speak 
of any language as an art in the sense of its having 
been elaborately and methodically formed. Philolo- 
gists now admit that conjugations, declensions, &c, ori- 
ginally 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 shew how easily we 
may err : a Crinoid sometimes consists of no less 
than 150,000 pieces of shell, 40 all arranged with per- 
fect 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 alike, excepting on the opposite 
sides of the body. He iustlv considers the differen- 
tiation and specialisation of organs^ as the test of per- 
fection. So with languages, the most symmetrical and 
complex ought not to be ranked above irregular, abbre- 



45 Quoted by C. S. Wake, ' Chapters on Man,' 1868, p. 101. 

46 Buckland, ' Bridgewater Treatise,' p. 411. 



62 THE DESCENT OF MAN. Part I. 

viated, and bastardised languages, which have borrowed 
expressive words and useful forms of construction from 
various conquering, or conquered, or immigrant races. 

From these few and imperfect remarks I conclude 
that the extremely complex and regular construction of 
many barbarous languages, is no proof that they owe 
their origin to a special act of creation. 47 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. 

Self -consciousness, Individuality, Abstraction, General 
Ideas, &c. — It would be useless to attempt discussing 
these high faculties, which, according to several recent 
writers, make the sole and complete distinction between 
man and the brutes, for hardly two authors agree in their 
definitions. Such faculties could not have been fully 
developed in man until his mental powers had advanced 
to a high standard, and this implies the use of a perfect 
language. No one supposes that one of the lower ani- 
mals reflects whence he comes or whither he goes, — 
what is death or what is life, and so forth. But can 
we feel sure that an old dog with an excellent memory 
and some power of imagination, as shewn by his 
dreams, never reflects on his past pleasures in the 
chase ? and this would be a form of self-consciousness. 
On the other hand, as Biiehner 48 has remarked, how 
little can the hard-worked wife of a degraded Australian 
savage, who uses hardly any abstract words and cannot 
count above four, exert her self-consciousness, or reflect 
on the nature of her own existence. 



47 See some good remarks on the simplification of languages, by Sir 
J. Lubbock, ' Origin of Civilisation,' 1870, p. 278. 

48 ' Conferences sur la The'orie Darwinienne,' French translat., 1869, 
p. 132. 



Chap. II. MENTAL POWERS. 63 

That animals retain their mental individuality is 
unquestionable. When my voice awakened a train of 
old associations in the mind of the above-mentioned 
dog. he must have retained his mental individuality, 
although every atom of his brain had probably under- 
gone change more than once during the interval of five 
years. This dog might have brought forward the 
argument 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 hypothesis is a false one." 4ft 

Sense of Beauty. — This sense has been declared to 
be peculiar to man. Bat when we behold male birds 
elaborately displaying their plumes and splendid colours 
before the females, whilst other birds not thus deco- 
rated make no such display, it is impossible to doubt 
that the females admire the beauty of their male part- 
ners. As women everywhere deck themselves with 
these plumes, the beauty of such ornaments cannot be 
disputed. The Bower-birds by tastefully ornamenting 
their playing-passages with gaily-coloured objects, as 
do certain humming-birds their nests, offer additional 
evidence that they possess a sense of beauty. So with 
the song of birds, the sweet strains poured forth by the 
males 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 appre- 
ciating the beautiful colours, the ornaments, and voices 



49 



The Rev. Dr. J. M'Cann, ' Anti-Darwinism,' 1869, p. 13. 



64 THE DESCENT OF MAN. Part I. 

of their male partners, all the labour and anxiety exhi- 
bited by them in displaying their charms before the 
females would have been thrown away ; and this it is 
impossible to admit. Why certain bright colours and 
certain sounds should excite pleasure, when in harmony, 
cannot, I presume, be explained any more than why 
certain flavours and scents are agreeable ; but assuredly 
the same colours and the same sounds are admired by 
us and by many of the lower animals. 

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, as will hereafter be shewn, 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 admired by most savages, it 
might be urged that their aesthetic faculty was not so 
highly developed as in certain animals, for instance, in 
birds. Obviously no animal would be capable of ad- 
miring such scenes as the heavens at night, a beautiful 
landscape, or refined music; but such high tastes, de- 
pending as they do on culture and complex associa- 
tions, are not enjoyed by barbarians or by uneducated 
persons. 

Many of the faculties, which have been of inesti- 
mable service to man for his progressive advance- 
ment, such as the powers of the imagination, wonder, 
curiosity, an undefined sense of beauty, a tendency 
to imitation, and the love of excitement or novelt , 
could not fail to have led to the most capricious 
changes of customs and fashions. I have alluded to 
this point, because a recent writer 50 has oddly fixed 
on Caprice " as one of the most remarkable a d 



50 • The Spectator,' Dec. 4th, 1869, p. 1430. 



Chap. II. MENTAL POWERS. 65 

" typical differences between savages and brutes." But 
not only can we perceive how it is that man is capri- 
cious, but the lower animals are, as we shall hereafter 
see, capricious in their affections, aversions, and sense 
of beauty. There is also good reason to suspect that 
they love novelty, for its own sake. 

Belief in God — 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 
travellers, 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. 51 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 bv the highest intellects that have ever 
lived. 

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 almost universal 
with the less civilised 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 have craved 
to understand what was passing around him, and 
have vaguely speculated on his own existence. As 



51 See an excellent article on this subject by the Eev. 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 Civilisation.' 
1870. 

VOL. I. F 



66 THE DESCENT OF MAN. Part I. 

Mr. M'Lennan 52 has remarked, " Some explanation 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 pre- 
" sence 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 probable, 
as Mr. Tylor has clearly shewn, 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 believed 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." 53 But until the 
above-named faculties of imagination, curiosity, reason, 
&c, 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. 



32 The Worship of Animals and Plants, in the ' Fortnightly Keview,' 
Oct. 1, 1869, p. 422. 

53 Tylor, 'Early History of Mankind,' 1865, p. 6. See also the three 
striking chapters on the Development of Eeligion, in Lubbock's ' Origin 
of Civilisation,' 1870. In a like manner Mr. Herbert Spencer, in his 
ingenious essay in the ' Fortnightly Review' (May 1st, 1870, p. 535), 
accounts 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 shews 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 exi^t as 
a spirit, is held sacred, and worshipped as a god. Nevertheless I cannot 
but suspect that there is a still earlier and ruder stage, when anything 
which manifests power or movement is thought to be endowed with 
some form of life, and with mental faculties analogous to our own. 



Chap. II. MENTAL POWERS. 67 

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 occasionally 
moved an open parasol, which would have been wholly 
disregarded 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 apparent cause 
indicated the presence of some strange living agent, and 
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 
experienced. 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 punish- 
ment 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 practised 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 the belief in good 
spirits. 

f 2 



68 THE DESCENT OF MAN. Part I. 

The feeling of religious devotion is a highly com- 
plex one, consisting of love, complete submission to 
an exalted and mysterious superior, a strong sense of 
dependence, 54 fear, reverence, gratitude, hope for the 
future, and perhaps other elements. No being could 
experience so complex an emotion until advanced in 
his intellectual and moral faculties to at least a mode- 
rately high level. Nevertheless we see some distant 
approach to this state of mind, in the deep love of a 
dog for his master, associated with complete submission, 
some fear, and perhaps other feelings. The behaviour 
of a dog when returning to his master after an ab- 
sence, 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 shewn in every action. Professor Braubach 55 goes 
so far as to maintain that a dog looks on his master as 
on a god. 

The same high mental faculties which first led man 
to believe in unseen spiritual agencies, then in fetish- 
ism, polytheism, and ultimately in monotheism, would 
infallibly lead him, as long as his reasoning powers 
remained poorly developed, to various strange super- 
stitions and customs. Many of these are terrible to 
think of — such as the sacrifice of human beings to a 
blood-loving 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 
shew us what an infinite debt of gratitude we owe to 
the improvement of our reason, to science, and our 



54 See an able article on the Psychical Elements of Keligion, by 
Mr. L. Owen Pike, in ' Anthropolog. Keview/ April, 1870, p. lxiii. 
" ' Keligion, Moral, &c, der Darwin'schen Art-Lehre.' 1869, s. 53. 



Chap. II. MENTAL POWERS. 69 

accumulated knowledge. 56 As Sir J. Lubbock has well 
observed, "it is not too much to say that the horrible 
" dread of unknown evil hansrs 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 
occasional mistakes of the instincts of the lower animals. 



56 'Prehistoric Times,' 2nd edit. p. 571. In this work (at p. 553) 
there will be found an excellent account of the many strange and 
capricious customs of savages. 



70 THE DESCENT OF MAN. Part I. 



CHAPTER III. 

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 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 — Trans- 
mission of moral tendencies — Summary. 

I fully subscribe to the judgment of those writers 1 
who maintain 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 Mack- 
intosh 2 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 without 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. 
Immanuel 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 



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

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



Chap. III. MOIIAL SENSE. 71 

" reverence, if not always obedience ; before whom all 
" appetites are dumb, however secretly they rebel ; 
" whence thy original ? " 3 

This great question has been discussed by many 
writers 4 of 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 ap- 
proached it exclusively from the side of natural history. 
The investigation possesses, also, some independent in- 
terest, as an attempt to see how far the study of the 
lower animals can throw light on one of the highest 
psychical faculties of man. 

The following proposition seems to me in a high 
degree probable — namely, that any animal whatever, 
endowed with well-marked social instincts, 5 would inevi- 
tably acquire a moral sense or conscience, as soon as 



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

4 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 
name, and those of Mr. Lecky, Mr. Shadworth Hodgson, and Sir J. 
Lubbock, as well as of others, may be added. 

5 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, p. 46), of the social feelings 
as a " powerful natural sentiment," and as " the natural basis of 
" sentiment for utilitarian morality ; " but on the previous page he 
says, " 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 hesita- 
tion that I venture to differ from so profound a thinker, but it can 
hardly be disputed that the social feelings 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 acquired by each individual 
during his lifetime. On the general theory of evolution this is at 
least extremely improbable. 



72 THE DESCENT OF MAN. Part I. 

its intellectual powers had become as well developed, 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 evi- 
dently 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 which invariably results, as we shall 
hereafter see, from any unsatisfied instinct, would arise, 
as often as it was perceived that the enduring and 
always 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 impres- 
sion. It is clear that many instinctive desires, such as 
that of hunger, are in their nature of short duration ; 
and after being satisfied are not readily or vividly re- 
called. Thirdly, after the power of language had been 
acquired and the wishes of the members of the same 
community could be distinctly expressed, the common 
opinion how each member ought to act for the public 
good, would naturally become to a large extent the guide 
to action. But the social instincts would still give the 
impulse to act for the good of the community, this im- 
pulse being strengthened, directed, and sometimes even 
deflected by public opinion, the power of which rests, as 
we shall presently see, on instinctive sympathy. Lastly, 
habit in the individual would ultimately play a very 



Chap. III. MORAL SENSE. 73 

important part in guiding the conduct of each member ; 
for the social instincts and impulses, like all other in- 
stincts, would be greatly strengthened by habit, as 
would obedience to the wishes and judgment of the com- 
munity. These several subordinate propositions must 
now be discussed ; and some of them at considerable 
length. 

It may be well first to premise that 1 do not wish to 
maintain that any strictly social animal, if its intellec- 
tual faculties were to become as active and as highly 
developed as in man, would acquire exactly the same 
moral sense as ours. In the same manner 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 dif- 
ferent lines of conduct. If, for instance, to take an ex- 
treme case, men were reared under precisely the same 
conditions as hive-bees, there can hardly be a doubt 
that oar 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 social animal, would in our sup- 
posed case gain, as it appears to me, some feeling of 
right and wrong, or a conscience. For each individual 
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 which impulse should be followed; and satis- 
faction or dissatisfaction would be felt, as past impres- 
sions 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 : the one 



74 THE DESCENT OF MAN. Part I. 

would have been right and the other wrong; but to 
these terms I shall have to recur. 

Sociability. — Animals of many kinds are social ; we 
find even distinct species living together, as with some 
American inoDkeys, and with the 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 mise- 
rable horses, dogs, sheep, &c. are when separated from 
their companions ; and what affection at least the two 
former kinds show on their reunion. It is curious to 
speculate on the feelings of a dog, who will rest peace- 
fully 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 dis- 
mally. We will confine our attention to the higher 
social animals, excluding insects, although these aid 
each other in many important ways. The most common 
service which the higher animals perform for each other, 
is the warning each other of danger by means of the 
united senses of alL Every sportsman knows, as Dr. 
Jaeger remarks, 6 how difficult 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 who first discovers an enemy, warns the others. 
Kabbits stamp loudly on the ground with their hind-feet 
as a signal : sheep and chamois do the same, but with 
their fore-feet, uttering likewise a whistle. Many birds 
and some mammals post sentinels, which in the case of 
seals are said 7 generally to be the females. The leader 
of a troop of monkeys acts as the sentinel, and utters 
cries expressive both of danger and of safety. 8 Social 



6 ' Die Darwin'sche Theorie,' s. 101. 

■ Mr. R. Brown in ' Proc. Zoolog. Soc/ 1868, p. 409. 

8 Brehm, ' Thierleben,' B. i. 1864, s. 52, 79. For the case of the 



Chap. III. MOEAL SENSE. 75 

animals perform many little services for each other: 
horses nibble, and cows lick each other, on any spot 
which itches : monkeys search for each other's 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 each 
other : thus wolves and some other beasts of prey hunt 
in packs, and aid each other in attacking their victims. 
Pelicans fish in concert. The Hamadryas 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. The males of some ruminants come 
to the front when there is danger and defend the herd 
with their horns. I shall also in a future chapter give 
cases of two young wild bulls attacking an old one in 
concert, and of two stallions together trying to drive 
away a third stallion from a troop of mares. Brehm 
encountered in Abyssinia a great troop of baboons which 
were crossing a valley : some had already ascended the 
opposite mountain, and some were still in the valley : 
the 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 
precipitately retreated. They were again encouraged 
to the attack ; but by this time all the baboons had re- 
ascended the heights, excepting a young one, about six 



monkeys extracting thorns from each other, see s. 54. With respect to 
the Hamadryas turning over stones, the fact is given (s. 76) on the 
evidence of Alvarez, whose observations Brehm thinks quite trust- 
worthy. For the cases of the old male baboons attacking the dogs, see 
s. 79 ; and with respect to the eagle, s. 56. 



76 THE DESCENT OF MAN. Part I. 

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 triumphantly 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 Cercopithecus, 
which, by clinging to a branch, was not at once carried 
off; it cried loudly for assistance, upon which the other 
membeis 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 remarks, assuredly 
would never again attack a monkey in a troop. 

It is certain that associated animals have a feeling of 
love for each other which is not felt by adult and non- 
social animals. How far in most cases they actually 
sympathise with each other's pains and pleasures is 
more doubtful, especially with respect to the latter. 
Mr. Buxton, however, who had excellent means of 
observation, 9 states that his macaws, which lived free in 
Norfolk, took "an extravagant interest" in a pair 
with a nest, and whenever the female left it, she was 
surrounded by a troop " screaming horrible accla- 
" mations in her honour." It is often difficult to judge 
whether animals have any feeling for each other's 
sufferings. Who can say what cows fee], when they 
surround and stare intently on a dying or dead 
companion? 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 



9 « Annals and Mag. of Nat. Hist.' Novcml er, 1868, p. 382. 



Chap. III. MORAL SENSE. 77 

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 conduct is not much worse than that 
of the North American Indians who leave their feeble 
comrades to perish on the plains, or the Feegeans, who, 
when their parents get old or fall ill, bury them alive. 10 

Many animals, however, certainly sympathise with 
each other's distress or clanger. This is the case even 
with birds ; Capt. Stansbury n found on a salt lake in 
Utah an old and completely blind pelican, which was 
very fat, and must have been long and well fed 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 cock. We may, if we choose, call 
these actions instinctive ; but such cases are much too 
rare for the development of any special instinct. 12 I 
have myself seen a dog, who never passed a great 
friend of his, a cat which lay sick in a basket, with- 
out 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 before been made. The little crea- 



10 Sir J. Lubbock, ' Prehistoric Times,' 2nd edit. p. 416. 

11 As quoted by Mr. L. H. Morgan, * The American Beaver,' 18GS, 
p. 272. Capt. Stansbury also gives an interesting account of the man- 
ner 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. 

12 As Mr. Bain states, " effective aid to a sufferer springs from syra- 
" pathy proper:" ' Mental and Moral Science,' 1868, p. 245. 



78 THE DESCENT OF MAN. Part I. 

ture instantly jumped away, but after the pretended 
beating was over, it was really pathetic to see how per- 
se veringly he tried to lick his mistress's face and com- 
fort her. Brehm 13 states that when a baboon in con- 
finement 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 Cercopi- 
theci to defend their young comrades from the dogs 
and the eagle. I will give only one other instance of 
sympathetic and heroic conduct in 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 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 
dreadfully afraid of the great baboon. Nevertheless, as 
soon as he saw his friend the keeper in peril, he rushed 
to the rescue, and by screams and bites so distracted the 
baboon that the man was able to escape, after running 
great risk, as the surgeon who attended him thought, 
of his life. 

Besides love and sympathy, animals exhibit other 
qualities which in us would be called moral ; and I agree 
with Agassiz 14 that dogs possess something very like a 
conscience. They certainly possess some power of self- 
command, and this does not appear to be wholly the 
result of fear. As Braubach 15 remarks, a dog will 
refrain from stealing food in the absence of his master. 
Dogs have long been accepted as the very type of 
fidelity and obedience. All animals living in a body 
which defend each other or attack their enemies 



13 ' Thierleben,' B. i. s. 85. 

14 ' De l'Espece et de la Class.' 1869, p. 97. 

15 ' Der Darwin'scken Art-Lehre,' 1869, s. 54. 



Chap. III. MORAL SENSE. 79 

in concert, must be in some degree faithful to each 
other; and those that follow a leader must be in 
some degree obedient. When the baboons in Abys- 
sinia 16 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 ; but as soon as they are sure 
that there is no danger, all show their joy by much 
clamour. 

With respect to the impulse which leads certain 
animals to associate together, and to aid each other 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 in 
other cases of prevented instinctive actions. 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 foxhound delights 
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 miserable if prevented from migrat- 
ing, and perhaps they enjoy starting on their long 
flight. Some few instincts are determined solely by 
painful feelings, as by fear, which leads to self-preser- 
vation, or is specially directed against certain enemies. 
No one, I presume, can analyse the sensations of 
pleasure or pain. In many cases, however, it is pro- 
bable that instincts are persistently followed from the 



18 Brelim, ■ Thierleben,' B. i. s. 76. 



80 THE DESCENT OF MAN. Part I. 

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 erro- 
neous. Although a habit may be blindly and implicitly 
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 expe- 
rienced ; and this is especially true in regard to persons 
of feeble intellect. 

It has often been assumed that animals were in the 
first place rendered social, and that they feel as a con- 
sequence uncomfortable when separated from each other, 
and comfortable whilst together ; but it is a more pro- 
bable view that these sensations were first developed, in 
order that those animals which would profit by living 
in society, should be induced to live together. In the 
same manner as the sense of hunger and the pleasure of 
eating were, no doubt, first acquired in order to induce 
animals to eat. The feeling of pleasure from society 
is probably an extension of the parental or filial affec- 
tions ; and this extension may be in chief part attributed 
to natural selection, but perhaps in part to mere habit. 
For 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 com- 
rades and lived solitary would perish in greater numbers. 
With respect to the origin of the parental and filial 
affections, which apparently lie at the basis of the 
social affections, it is hopeless to speculate ; but we 



Chap. III. MORAL SENSE. 81 

may infer that they have been to a large extent gained 
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, 
instead of loving, their nearest relations having been 
here of service to the community. 

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 then hardly 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, fatigue, revives in us some recollection 
" of these states, which are painful even in idea." We 
are thus impelled to relieve the sufferings of another, 
in order that our own painful feelings may be at the 
same time relieved. In like manner we are led to 
participate in the pleasures of others. 17 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 



17 See the first and striking chapter in Adam Smith's ' Theory of 
Moral Sentiments.' Also Mr. Bain's ' Mental .and Moral Science,' 
18G8, p. 244, and 275-282. Mr. Bain states, that "sympathy is, 
' indirectly, a source of pleasure to the sympathiser ; " 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 ins'.inct. 

vol. i. a 



82 THE DESCENT OF MAN. Part I. 

sight of suffering, independently of love, would suffice 
to call up in us vivid recollections and associations. 
Sympathy may at first have originated in the manner 
above suggested; but it seems now to have become 
an instinct, which is especially directed towards be- 
loved objects, in the same manner as fear with ani- 
mals is especially directed against certain enemies. As 
sympathy is thus directed, the mutual love of the 
members of the same community will extend its limits. 
No doubt a tiger or lion feels sympathy for the suffer- 
ings of its own young, but not for any other animal. 
With strictly social animals the feeling will be more 
or less extended to all the associated members, as we 
know to be the case. With mankind selfishness, expe- 
rience, and imitation probably add, as Mr. Bain has 
shewn, to the power of sympathy ; for we are led 
by the hope of receiving good in return to perform 
acts of sympathetic kindness to others ; and there can 
be no doubt that the feeling of 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 
each other, 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. 

In many cases it is impossible to decide whether 
certain social instincts have been acquired through 
natural selection, or are the indirect result of other 
instincts and faculties, such as sympathy, reason, expe- 
rience, 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 



Chap. III. MORAL SENSE. 83 

the indirect result of any other faculty ; it must there- 
fore 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 
originated 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 performance and more distress in their 
prevention than others ; or, which is probably quite as 
important, they are more persistently followed through 
inheritance without exciting any special feeling of plea- 
sure or pain. We are ourselves conscious that some 
habits are much more difficult to cure or change than 
others. Hence a struggle mav often be observed in 
animals between different instincts, or between an 
instinct and some habitual disposition ; as when a dog 
rushes after a hare, is rebuked, pauses, hesitates, pursues 
again or returns ashamed to his master ; or as between 
the love of a female dog for her yoimg 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 conquering another, is the migratory instinct 
conquering the maternal instinct. The former is won- 
derfully 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, where they could still continue to 
live, and thus unintentionally to commit suicide. Every 
one knows how strong the maternal instinct is, leading 
even timid birds to face great danger, though with 
hesitation and in opposition to the instinct of self- 

G 2 



84 THE DESCENT OF MAN. Part I. 

preservation. Nevertheless trie migratory instinct is so 
powerful that late in the autumn swallows and house- 
martins frequently desert their tender young, leaving 
them to perish miserably in their nests. 18 

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 well 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 para- 
mount force. 

Man a social animal. — Most persons 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 confinement is one of the severest 
punishments which can be inflicted. Some authors sup- 
pose that man primevally lived in single families ; but 
at the present day, though single families, or only two 
or three together, roam the solitudes of some savage 
lands, they are always, as far as I can discover, friendly 
with other families inhabiting the same district. Such 
families occasionally meet in council, and they unite 



18 This fact, the Eev. L. Jenyns states (see his edition of ' White's 
Nat. Hist, of Selborne,' 1853, p. 204) was first recorded by the illus- 
trious Jenner, in ' Phil. Transact.' 1824, and has since been confirmed 
by several observers, especially by Mr. Blackwall. This latter careful 
observer 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 
deserted and left behind. See Blackwall, 'Researches in Zoology,' 
1834, pp. 108, 118. For some additional evidence, although this is nut 
wanted, see Leroy, 4 Lettres Phil.' 1802, p. 217. 



Chap. III. MORAL SENSE. 85 

for tlieir common defence. It is no argument against 
savage man being a social animal, that the tribes in- 
habiting adjacent districts are almost always at war 
with each other ; for the social instincts never extend 
to all the individuals of the same species. Judging 
from the analogy of the greater number of the Quad- 
rumana, it is probable that the early ape-like pro- 
genitors of man were 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 ex- 
tremely remote period some degree of instinctive love 
and sympathy for his fellows. We are indeed all con- 
scious that we do possess such sympathetic feelings ; 19 
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, it is also probable that he 
would inherit a tendency to be faithful to his comrades, 
for this quality is common to most social animals. He 
would in like manner possess some capacity for self- 
command, and perhaps of obedience to the leader of 
the community. He would from an inherited tendency 
still be willing to defend, in concert 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 



19 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 iu- 
" different 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." //-" ' ^ 

ILtB 



8G THE DESCENT OF MAN. Part I. 

scale are guided almost exclusively, and those which 
stand higher in the scale are largely guided, in the aid 
which they give to the members of the same community, 
by special instincts ; but they are likewise in part im- 
pelled by mutual love and sympathy, assisted appa- 
rently 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 respect by reason and experience. In- 
stinctive sympathy would, also, cause him to value highly 
the approbation of his fellow-men ; for, as Mr. Bain has 
clearly shewn, 20 the love of praise and the strong feeling 
of glory, and the still stronger horror of scorn and in- 
famy, " are due to the workings of sympathy." Conse- 
quently man would be greatly influenced by the wishes, 
approbation, and blame of his fellow-men, as expressed 
by their gestures and language. Thus the social in- 
stincts, 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 many of his best 
actions ; but his actions are largely determined by the 
expressed wishes and judgment of his fellow-men, and 
unfortunately still oftener by his own strong, selfish 
desires. But as the feelings of love and sympathy and 
the power of self-command become strengthened by 
habit, and as the power of reasoning becomes clearer so 
that man can appreciate the justice of the judgments of 
his fellow-men, he will feel himself impelled, independ- 
ently of any pleasure or pain felt at the moment, to 
certain lines of conduct. He may then say, 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. 

20 ' Mental and Moral Science/ 1868, p. 254. 



Chap. III. MORAL SENSE. 87 

The more enduring Social Instincts conquer the less 
Persistent Instincts. — We have, however, not as yet con- 
sidered the main point, on which the whole question of 
the moral sense hinges. Why should a man feel that 
he ought to obey one instinctive desire rather than 
another ? Why does he bitterly regret if he has yielded 
to the 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 severe hunger? 

It is evident in the first place, that with mankind the 
instinctive impulses have different degrees of strength ; 
a young and timid mother urged by the maternal in- 
stinct will, without a moment's hesitation, run the 
greatest danger for her infant, but not for a mere fel- 
low-creature. Many a man, or even boy, who never 
before risked his life for another, but in whom courage 
and sympathy were well developed, has, disregarding the 
instinct of self-preservation, instantaneously plunged 
into a torrent to save a drowning fellow-creature. In 
this case man is impelled by the same instinctive mo- 
tive, which caused the heroic little American monkey, 
formerly described, to attack the great and dreaded 
baboon, to save his keeper. Such actions as the above 
appear to be the simple result of the greater strength of 
the social or maternal instincts than of any other instinct 
or motive ; for they are performed too instantaneously 
for reflection, or for the sensation of pleasure or pain ; 
though if prevented distress would be caused. 

I am aware that some persons maintain that actions 
performed impulsively, as in the above cases, do not 
come under the dominion of the moral sense, and 
cannot be called moral. They confine this term to 
actions done deliberately, after a victory over opposing 
desires, or to actions prompted by some lofty motive. 
But it appears scarcely possible to draw any clear line 



88 THE DESCENT OF MAN. Part I. 

of distinction of this kind ; though the distinction may 
be real. As far as exalted motives are concerned, many 
instances have been recorded of barbarians, destitute of 
any feeling of general benevolence towards mankind, 
and not guided by any religious motive, who have deli- 
berately as prisoners sacrificed their lives, 21 rather than 
betray their comrades ; and surely their conduct ought 
to be considered as moral. As far as deliberation and 
the victory over opposing motives are concerned, ani- 
mals may be seen doubting between opposed instincts, 
as in rescuing their offspring or comrades from dan- 
ger ; yet their actions, though done for the good of 
others, are not called moral. Moreover, an action 
repeatedly performed by us, will at last be done with- 
out deliberation or hesitation, and can then hardly be 
distinguished from an instinct ; yet surely no one will 
pretend that an action thus done 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, when they are performed 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 suppose that any of the lower animals have 



21 I have given one such case, namely of three Patagonian Indians 
who preferred being shot, one after the other, to betraying the plans of 
their companions in war (, Journal of Researches,' 1845,. p. 103). 



Chap. III. MORAL SENSE. 89 

this capacity ; therefore when 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 from the effects of slowly-gained 
habit, or impulsively through instinct. 

But to return to our more immediate subject ; al- 
though some instincts are more powerful than others, 
thus leading to corresponding actions, yet it cannot 
be maintained that the social instincts are ordinarily 
stronger in man, or have become stronger through 
long-continued habit, than the instincts, for instance, 
of self-preservation, hunger, lust, vengeance, &c. Why 
then does man regret, even though he may endeavour 
to banish any 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 in- 
cessantly passing through his mind with distinctness. 
Now with those animals which live permanently in a 
body, the social instincts are ever present and per- 
sistent. 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 in their company. 
So it is with ourselves. A man who possessed no trace 



90 THE DESCENT OF MAN. Part I. 

of such feelings would be an unnatural monster. On 
the other hand, the desire to satisfy hunger, or any 
passion, such as vengeance, 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 vivid- 
ness the feeling, for instance, of himger ; nor indeed, as 
has often been remarked, of any suffering. The in- 
stinct of self-preservation is not felt except in the pre- 
sence of danger ; and many a coward has thought him- 
self 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 possession is gene- 
rally a weaker feeling than the desire : many a thief, if 
not an habitual one, after success has wondered why he 
stole some article. 

Thus, as man cannot prevent old impressions con- 
tinually repassing through his mind, he will be com- 
pelled to compare the weaker impressions of, for in- 
stance, past hunger, or of vengeance satisfied or danger 
avoided at the cost of other men, with the instinct of 
sympathy and good-will to his fellows, which is still pre- 
sent and ever in some degree active in his mind. He 
will then feel in his imagination that a stronger instinct 
has yielded to one which now seems comparatively 
weak ; and then that sense of dissatisfaction will in- 
evitably be felt with which man is endowed, like every 
other animal, in order that his instincts may be obeyed. 
The case before given, of the swallow, affords an illus- 
tration, though of a reversed nature, of a temporary 
though for the time strongly persistent instinct con- 
quering 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, 



Chap. III. MORAL SENSE. 91 

and congregate in flocks. AYhilst the mother-bird is 
feeding or brooding over her nestlings, the maternal 
instinct is probably stronger than the migratory ; but 
the instinct which is more persistent 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 migra- 
tory instinct ceases to act, what an agony of remorse 
each bird w r ould feel, if, from being endowed with great 
mental activity, she could not prevent the image con- 
tinually passing before her mind of her young ones 
perishing in the bleak north from cold and hunger. 

At the moment of action, mam will no doubt be apt 
to follow the stronger impulse ; and though this may 
occasionally prompt him to the noblest deeds, it will 
far more commonly lead him to gratify his own desires 
at the expense of other men. But after their grati- 
fication, when past and weaker impressions are con- 
trasted with the ever-enduring social instincts, retri- 
bution will surely come. Man will then feel dissatis- 
fied with himself, and will resolve with more or less 
force to act differently for the future. This is con- 
science ; for conscience looks backwards and judges past 
actions, inducing that kind of dissatisfaction, which if 
weak we call regret, and if severe remorse. 

These sensations are, no doubt, different from those 
experienced when other instincts or desires are left 
unsatisfied; but every unsatisfied instinct has its own 
proper prompting sensation, as we recognise with hunger, 
thirst, &c. Man thus prompted, "will through long 
habit acquire such perfect self-command, that his desires 
and passions will at last instantly yield to his social 
sympathies, and there will no longer be a struggle 
between them. The still hungry, or the still revengeful 
man will not think of stealing food, or of wreaking his 



92 THE DESCENT OF MAN. Part I. 

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 in- 
herited habit, that it is best for him to obey his more 
persistent instincts. The imperious word ought seems 
merely to imply the consciousness of the existence of a 
persistent instinct, either innate or partly acquired, 
serving him as a guide, though liable to be disobeyed. 
We hardly use the word ought in a metaphorical sense, 
when we say hounds ought to hunt, pointers to point, 
and retrievers to retrieve their game. If they fail thus 
to act, 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 to a man, when re- 
called to mind, as strong as, or stronger than, his social 
instinct, he 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 disap- 
probation ; and few are so destitute of sympathy as not 
to feel discomfort when this is realised. If he has no 
such sympathy, 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, then he is 
essentially a bad man ; ffl 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. 

It is obvious that every one may with an easy con- 
science gratify his own desires, if they do not interfere 



27 Dr. Prosper Despine, in his 'Psychologic Naturelle,' ]868 (torn, 
i. p. 243 ; torn. ii. p. 169) gives many curious cases of the worst criminals, 
who apparently have been entirely destitute of conscience. 



Chap. III. MORAL SENSE. 93 

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 reasonable 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 addi- 
tional fear of divine punishment often supervenes. 

The strictly Social Virtues at first alone regarded. — 
The above view of the first 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 un- 
developed condition of this faculty in mankind. The 
virtues which must be practised, at least generally, by 
rude men, so that they may associate in a body, are 
those which are still recognised as the most important. 
But they are practised 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, trea- 
chery, &c, were common ; consequently such crimes 
within the limits of the same tribe "are branded 
" with everlasting infamy ; " ffl but excite no such senti- 
ment beyond these limits. A North-American Indian 
is well pleased with himself, and is honoured by others, 
when he scalps a man of another tribe ; and a Dyak 



23 Sec an able article in the ' North British Review,' 1867, p. 395. 
See also Mr. W. Bagehot's articles on the Importance of Obedience 
and Coherence to Primitive Man, in the ' Fortnightly Review,' 1867, 
p. 529, and 1868, p. 457, &c. 



94 THE DESCENT OF MAN. Pakt I. 

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, 24 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, 25 but rather from the 
courage displayed as an honourable act ; and it is still 
largely practised by some semi-civilised nations without 
reproach, for the loss to a nation of a single individual 
is not felt : whatever the explanation may be, suicide 
is rare amongst barbarians ; the negroes on the west 
coast of Africa offering, however, as I hear from Mr. 
W. Keade, in this respect an exception. It has been 
recorded that an Indian Thug conscientiously regretted 
that he had not strangled and robbed as many travellers 
as did his father before him. In a rude state of civilisa- 
tion the robbery of strangers is, indeed, generally con- 
sidered as honourable. 

The great sin of Slavery has been almost universal, and 
slaves have often been treated in an infamous manner. 
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, 26 and humanity 
with them is an unknown virtue. Nevertheless, feelings 
of sympathy and kindness are common, especially 



24 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. 

25 See the very interesting discussion on Suicide in Lecky's ' History 
of European Morals,' vol. i. 1869, p. 223. 

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



Chap. III. MORAL SENSE. 95 

during sickness, between the members of the same tribe, 
and are sometimes extended beyond the limits of the 
tribe. 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 practised by savages 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 shews. As soon as a tribe has 
a recognised 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 
civilised countries, a good, yet timid, man may be far 
more useful to the community than a brave one, we 
cannot help instinctively honouring the latter above 
a coward, however benevolent. Prudence, on the other 
hand, which does not concern the welfare of others, 
though a very useful virtue, has never been highly 
esteemed. As no man can practise 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 without 
a groan to the most horrid tortures to prove and 
strengthen his fortitude and courage ; and we cannot 



96 THE DESCENT OF MAN. Part I. 

help admiring him, or even an Indian Fakir, who, from 
a foolish religious motive, swings suspended by a hook 
buried in his flesh. 

The other self-regarding virtues, which do not ob- 
viously, though they may really, affect the welfare of 
the tribe, have never been esteemed by savages, though 
now highly appreciated by civilised nations. The 
greatest intemperance with savages is no reproach. 
Their utter licentiousness, not to mention unnatural 
crimes, is something astounding. 27 As soon, however, as 
marriage, whether polygamous or monogamous, becomes 
common, jealousy will lead to the inculcation of female 
virtue ; and this being honoured will tend to spread to the 
unmarried females. How slowly it spreads to the male 
sex we see at the present day. Chastity eminently 
requires self-command ; therefore it has been honoured 
from a very early period in the moral history of civilised 
man. As a consequence of this, the senseless practice 
of celibacy has been ranked from a remote period as 
a virtue. 28 The hatred of indecency, which appears to 
us so natural as to be thought innate, and which is so 
valuable an aid to chastity, is a modern virtue, apper- 
taining exclusively, as Sir G. Staunton remarks, 29 to 
civilised life. This is shewn by the ancient religious 
rites of various nations, by the drawings on the walls 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 primeval 
man, as good or bad, solely as they affect in an obvious 
manner the welfare of the tribe, — not that of the 
species, nor that of man as an individual member of the 



27 Mr. M'Lennan has given ('Primitive Marriage,' 1865, p. 176) a 
good collection of facts on this head. 

Lecky, ' History of European Morals,' vol. i. 1869, p. 109. 
29 'Embassy to China,' vol. ii. p. 348. 



28 



Chap. III. MOKAL SENSE. 97 

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. Secondly, 
insufficient powers of reasoning, so that the bearing of 
many virtues, especially of the self-regarding virtues, on 
the general welfare of the tribe is not recognised. 
Savages, for instance, fail to trace the multiplied evils 
consequent on a want of temperance, chastity, &c. 
And, thirdly, weak power of self-command; for this 
power has not been strengthened through long-con- 
tinued, perhaps inherited, habit, instruction and religion. 
I have entered into the above details on the immor- 
ality of savages, 30 because some authors have recently 
taken a high view of their moral nature, or have attri- 
buted most of their crimes to mistaken benevolence. 31 
These authors appear to rest their conclusion on savages 
possessing, as they undoubtedly do possess, and often 
in a high degree, those virtues which are serviceable, 
or even necessary, for the existence of a tribal com- 
munity. 

Concluding Remarks. — Philosophers of the derivative 32 
school of morals formerly assumed that the foundation 
of morality lay in a form of Selfishness ; but more 
recently in the " Greatest Happiness principle." Ac- 
cording to the view given above, the moral sense is 



30 See on this subject copious evidence in Chap. vii. of Sir J. 
Lubbock, ' Origin of Civilisation,' 1870. 

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

32 This term is used in an able article in the ' Westminister Eeview,' 
Oct. 1S69, p. 498. For the Greatest Happiness principle, see J. S. 
Mill, ' Utilitarianism,' p. 17. 

VOL. I. H 



98 THE DESCENT OF MAN. Part I- 

fundamentally identical with the social instincts; and 
in the case of the lower animals it would be absurd to 
speak of these instincts as having been developed from 
selfishness, or for the happiness of the community. 
They have, however, certainly been developed for the 
general good of the community. The term, general 
good, may be defined as the means by which the great- 
est possible number of individuals can be reared in 
full vigour and. health, with all their faculties perfect, 
under the conditions to which they are exposed. As 
the social instincts both of man and the lower animals 
have no doubt been developed by the same steps, it 
would be advisable, if found practicable, to use the 
same definition in both cases, and to take as the test 
of morality, the general good or welfare of the com- 
munity, 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 more appropriate to say that he acts 
for the general good or welfare, 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 at an early period in the history of man, the ex- 
pressed wishes of the community will have naturally 
influenced to a large extent the conduct of each mem- 
ber ; and as all wish for happiness, the " greatest happi- 
ness principle" will have become a most important 
secondary guide and object ; the social instincts, includ- 
ing sympathy, always serving as the primary impulse 
and guide. Thus the reproach of laying the foundation 
of the most noble part of our nature in the base prin- 
ciple of selfishness is removed ; unless indeed the satis- 



Chap. III. MORAL SENSE. 99 

faction which every animal feels when it follows its 
proper instincts, and the dissatisfaction felt when pre- 
vented, be called selfish. 

The expression of the wishes and judgment of the 
members of the same community, at first by oral and 
afterwards by written language, serves, as just re- 
marked, as a most important secondary guide of 
conduct, in aid of the social instincts, but sometimes 
in opposition to them. This latter fact is well exem- 
plified by the Law of Honour, that is the law of the 
opinion of our equals, and not of all our country- 
men. The breach of this law, even when the breach 
is known to be strictly accordant with true mo- 
rality, has caused many a man more agony than a real 
crime. We recognise 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 eti- 
quette. 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 from weak powers 
of reasoning. Hence the strangest customs and super- 
stitions, in complete opposition to the true welfare and 
happiness of mankind, have become all-powerful through- 
out the world. We see this in the horror felt by a 
Hindoo who breaks his caste, in the shame of a Maho- 
metan woman who exposes her face, and in innumerable 
other instances. It would be difficult to distinguish 
between the remorse felt by a Hindoo who has eaten 
unclean food, from that felt after committing 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 

h 2 



100 THE DESCENT OF MAN. Part I. 

quarters of the world, so deeply impressed on the mind 
of men ; but it is worthy of remark that a belief con- 
stantly 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 in- 
stinct is that it is followed independently of reason. 
Neither can Ave say why certain admirable virtues, such 
as the love of truth, are much more highly appre- 
ciated by some savage tribes than by others ; ^ nor, 
again, why similar differences prevail even amongst 
civilised nations. Knowing how firmly fixed many 
strange customs and superstitions have become, we 
need feel no surprise that the self-regarding virtues 
should now appear to us so natural, supported as they 
are by reason, as to be thought innate, although 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' owe their origin 
to public opinion, when matured by experience and 
cultivated ; for they are not practised by rude tribes. 

As man advances in civilisation, and small tribes 
are united into larger communities, the simplest reason 
would tell each individual that he ought to extend his 
social instincts and sympathies to all the members of 
the same nation, though personally unknown to him. 
This point being once reached, there is only an arti- 

83 Good instances are given by Mr. Wallace in ' Scientific Opinion,' 
Sept. 15, 1869 ; and more fully in his ' Contributions to the Theory of 
Natural Selection,' 1S70, p. 353. 



Chap. III. MORAL SENSE. 101 

fieial barrier to prevent his sympathies extending to the 
men of all nations and races. If, indeed, such men are 
separated from him by great differences in appearance 
or habits, experience unfortunately shews 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 shewn by their abhorrent gladiatorial 
exhibitions. The very idea of humanity, as far as I 
could observe, was new to most of the G-auchos of the 
Pampas. This virtue, one of the noblest with which 
man is endowed, seems to arise incidentally from our 
sympathies becoming more tender and more widely dif- 
fused, until they are extended to all sentient beings. 
As soon as this virtue is honoured and practised by some 
few men, it spreads through instruction and example to 
the young, and eventually through public opinion. 

The highest stage in moral culture at which we can 
arrive, is when we recognise 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." 34 
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 habi- 
" tual thoughts, such also will be the character of thy 
" mind; for the soul is dyed by the thoughts." 35 

Our great philosopher, Herbert Spencer, has recently 
explained his views on the moral sense. He says, 36 " I 



34 Tennyson, ■ Idylls of the King,' p. 244. /CW ^ 

35 'The Thoughts of the Emperor M. Aurelius Anton h^u^Enp S hf ( 
translat., 2nd edit., 186'.', p. 112. Marcus Aurelius was boynQS). fl£l . 

36 Letter to Mr. Mill in Bain's 'Mental and Moral S/igte^lSD^ 
P. 722. 'UBR<- 



&\ N4» ■* -i 



102 THE DESCENT OF MAN. Part I. 

" believe that the experiences of utility organised and 
" consolidated through all past generations of the human 
" race, have been producing corresponding modifications, 
" which, by continued transmission and accumulation, 
" have become in us certain faculties of moral intuition — 
" certain emotions responding to right and wrong con- 
" duct, which have no apparent basis in the individual 
" experiences of utility." There is not the least inhe- 
rent improbability, as it seems to me, in virtuous ten- 
dencies being more or less strongly inherited ; for, not 
to mention the various dispositions and habits trans- 
mitted by many of our domestic animals, I have heard 
of 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 so rare a crime in the wealthy classes, 
we can hardly account by accidental coincidence for the 
tendency occurring in two or three members of the 
same family. If bad tendencies are transmitted, it is 
probable that good ones are likewise transmitted. Ex- 
cepting 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. We have, however, as yet, hardly 
sufficient evidence on this head. 

Even the partial transmission of virtuous tendencies 
would be an immense assistance to the primary impulse 
derived directly from the social instincts, and indirectly 
from the approbation of our fellow-men. Admitting 
for the 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 organisation through 
habit, instruction, and example, continued during several 
generations in the same family, and in a quite subor- 
dinate degree, or not at all, by the individuals pos- 



Chap. III. MORAL SENSE. 103 

sessing 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, super- 
stitions, and tastes, such as the horror of a Hindoo for 
unclean food, ought on the same principle to be trans- 
mitted. Although this in itself is perhaps not less pro- 
bable than that animals should acquire inherited tastes 
for certain kinds of food or fear of certain foes, I have 
not met with any evidence in support of the trans- 
mission of superstitious customs or senseless habits. 

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, and some feeling of sym- 
pathy. 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 sufficient knowledge to reject 
baneful customs and superstitions ; as he regarded 
more and more not only the welfare but the happi- 
ness of his fellow-men ; as from habit, following on 
beneficial experience, instruction, and example, his 
sympathies became more tender and widely diffused, 
so as to extend to the men of all races, to the im- 
becile, the 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. 37 

As a struggle may sometimes be seen going on 

37 A writer in the 'North British Keview' (July, 1869, p. 531), well 
capable of forming a sound judgment, expresses himself strongly to this 



104 THE DESCENT OF MAN. Part I. 

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 at the moment, stronger impulses 
or desires. This, as Mr. Galton 38 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, analogous to that felt from other un- 
satisfied instincts, called in this case conscience ; for we 
cannot prevent past images and impressions continually 
passing through our minds, and these in their weakened 
state we compare with the ever-present social instincts, 
or with habits gained in early youth and strengthened 
during our whole lives, perhaps inherited, so that they 
are at last rendered almost as strong as instincts. 
Looking to future generations, there is no cause to fear 
that the social instincts will grow weaker, and we may 
expect that virtuous habits will grow stronger, becoming 
perhaps fixed by inheritance. In this case the struggle 
between our higher and lower impulses will be less 
severe, and virtue will be triumphant. 

Summary of the two last Chapters. — 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 nuts, 



effect. Mr. Lecky (' Hist, of Morals,' vol. i. p. 143) seems to a certain 
extent to coincide. 

38 See his remarkable work on ' Hereditary Genius,' 1SG9, p. 349. 
The Duke of Argyll ('Primeval Man,' 1869, p. 188) lias some good 
remarks on the contest in man's nature between right and wrong. 



Chap. III. SUMMARY. 105 

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 
reasouing, or solve a mathematical 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 coloured skin and fur of 
their partners in marriage. They would admit, that 
though they could make other apes understand by cries 
some of their perceptions 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 
acknowledge that disinterested love for all living crea- 
tures, the most noble attribute of man, was quite be- 
yond their comprehension. 

Nevertheless the difference in mind between man 
and the higher animals, great as it is, is certainly 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 con- 
dition, 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 be main- 
tained that certain powers, such as self-consciousness, 
abstraction, &c, are peculiar to man, it may well be 
that these are the incidental results of other highly- 
advanced intellectual faculties; and these again are 
mainly the result of the continued use of a highly 
developed language. At what age does the new-born 
infant possess the power of abstraction, or become self- 



106 THE DESCENT OF MAN. Part I. 

conscious and reflect on its own existence ? We cannot 
answer ; nor can we answer in regard to the ascending 
organic scale. The half-art and half-instinct of lan- 
guage still bears the stamp of its gradual evolution. 
The ennobling belief in God is not universal with man ; 
and the belief in active spiritual agencies naturally fol- 
lows from his other mental powers. The moral sense 
perhaps affords the best and highest distinction between 
man and the lower animals ; but I need not say any- 
thing on this head, as I have so lately endeavoured 
to shew that the social instincts, — the prime principle 
of man's moral constitution 39 — 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. 

In a future 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 this at least is possible ought not 
to be denied, when we daily see their development in 
every infant ; and when we may trace a perfect grada- 
tion from the mind of an utter idiot, lower than that of 
the lowest animal, to the mind of a Newton. 



39 < The Thoughts of Marcus Aurelius,' &c, p. 139. 



Chap. IV. MANNER OF DEVELOPMENT. 107 



CHAPTEE IV. 

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 
increased use and disuse of parts — Arrested development — Re- 
version — 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 — Decrease in size of the canine teeth — Increased 
size and altered shape of the skull — Nakedness — AbseDce of 
a tail — Defenceless condition of man. 

We have seen in the first chapter that the home-logical 
structure of man, his embryological development and 
the rudiments which he still retains, all declare in the 
plainest manner that he is descended from some lower 
form. The possession of exalted mental powers is no 
insuperable objection to this conclusion. In order that 
an ape-like creature should have been transformed into 
man, it is necessary that this early form, as well as 
many successive links, should all have varied in mind 
and body. It is impossible to obtain direct evidence on 
this head; but if it can.be shewn that man now varies 
— that his variations are induced by the same general 
causes, and obey the same general laws, as in the case 
of the lower animals — there can be little doubt that 
the preceding intermediate links varied in a like 
maimer. The variations at each successive stage of 
descent must, also, have been in some manner accumu- 
lated and fixed. 



108 THE DESCENT OF MAN. Part I. 

The facts and conclusions to be given in this chapter 
relate almost exclusively to the probable means by 
which the transformation of man has been effected, 
as far as his bodily structure is concerned. The fol- 
lowing chapter will be devoted to the development of 
his intellectual and moral faculties. But the present 
discussion likewise bears on the origin of the different 
races or species of mankind, whichever term may be 
preferred. 

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, arid 
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. 1 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 
" homogeneous in blood, customs, and language as any 
" in existence " — and even with the inhabitants of so 
confined an area as the Sandwich. Islands. 2 An emi- 
nent dentist assures me that there is nearly as much 
diversity in the teeth, as in the features. The chief 
arteries so frequently run in abnormal courses, that it 
has been found useful for surgical purposes to calculate 



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. Aitktn Meigs in ' Proc. Acad. Nat. Sci.' Philadelphia, May, 
1866. On the Australians, see Huxley, in Lyell's ' Anticpiiity of Man,' 
1863, p. 87. On the Sandwich Islanders, Prof. J. Wyinan, ' Observa- 
tions on Crania,' Boston, 1868, p. 18. 



Chap. IV. MANNEE OF DEVELOPMENT. 1 09 

from 12,000 corpses how often each course prevails. 3 
The muscles are eminently variable : thus those of the 
foot were found by Prof. Turner 4 not to be strictly 
alike in any two out of fifty bodies ; and in some the 
deviations were considerable. Prof. Turner adds that 
the power of performing the appropriate movements 
must have been modified in accordance with the several 
deviations. Mr. J. Wood has recorded 5 the occurrence 
of 295 muscular variations in thirty-six subjects, and in 
another set of the same number no less than 558 varia- 
tions, reckoning both sides of the body as one. In the 
last set, not one body out of the thirty-six was " found 
" totally wanting in departures from the standard de- 
" scriptions of the muscular system given in anatomical 
" text-books." A single body presented the extraordi- 
nary number of twenty-five distinct abnormalities. The 
same muscle sometimes varies in many ways : thus 
Prof. Macalister describes 6 no less than twenty distinct 
variations in the palmaris accessorius. 

The famous old anatomist, Wolff, 7 insists that the 
internal viscera are more variable than the external 
parts: Nulla particula est quw non aliter et aliier 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 ears. 

The variability or diversity of the mental faculties 
in men of the same race, not to mention the greater 



3 ' Anatomy of the Arteries,' by E. Quain. 

4 ' Transact. Eoyal Soc.' Edinburgh, vol. xxiv. p. 1.75, 189. 

5 * Proc, Eoyal Soc.' 1867, p. 544 ; also 1868, p. 483, 524. There is 
a previous paper, 1866, p. 229. 

6 ' Proc. E. Irish Academy,' vol. x. 1868, p. 141. 

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



110 THE DESCENT OF MAN. Part I. 

differences between the men of distinct races, is so 
notorious that not a word need here be said. So it 
is with the lower animals, as has been illustrated by 
a few examples in the last chapter. 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 under confinement in 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 remark- 
able for intelligence. Eengger, also, insists on the di- 
versity in the various mental characters of the monkeys 
of the same species which he kept in Paraguay; 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 

I have elsewhere 9 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 famil} r ; and we 



8 Brehm, ' Thierleben,' B. i. s. 58, 87. Piengger, ' S'augethiere von 



Paraguay,' s. 57. 



9 k Variation of Animals and Plants under Domestication,' vol. ii. 
chap. xii. 



Chap. IV. MANNEK OF DEVELOPMENT. Ill 

now know through the admirable labours of Mr. G-alton 10 
that genius, which implies a wonderfully complex com- 
bination of high faculties, tends to be inherited ; and, 
on the other hand, it is too certain that insanity and 
deteriorated mental powers likewise run in the same 
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 animals, they staud in some relation with 
the conditions to which each species has been exposed 
during several generations. Domesticated animals vary 
more than those in a state of nature ; and this is appa- 
rently due to the diversified and changing nature of 
their conditions. The different races of man resemble 
in this respect 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 civilised nations, 
the members of which belong to different grades of rank 
and follow different occupations, presenting a greater 
range of character than the members of barbarous 
nations. But the uniformity of savages has often been 
exaggerated, and in some cases can hardly be said 
to exist. 11 It is nevertheless an error to speak of man, 
even if we look only to the conditions to which he 
has been subjected, as " far more domesticated " 12 than 



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

11 Mr. Bates remarks (' The Naturalist on the Amazons,' 18G3, vol. ii. 
p. 159 , with respect to the Indians of the same S. 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 
' ; Mongolian in breadth and prominence of cheek, spread of nostrils, 
" aud obliquity of eyes." 

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



112 THE DESCENT OF MAN. Part I. 

any other animal. Some savage races, such as the 
Australians, are not exposed to more diversified con- 
ditions than are many species which have very wide 
ranges. In another and much more important re- 
spect, man differs widely from any strictly domesti- 
cated animal ; for his breeding has not been controlled, 
either through methodical or unconscious selection. No 
race or body of men has been so completely subjugated 
by other men, that certain individuals have been pre- 
served and thus unconsciously selected, from being in 
some way more useful to their masters. Nor have 
certain male 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 law of me- 
thodical selection ; for it is asserted that many tall men 
were reared in the villages inhabited by the grenadiers 
with their tall wives. 

If we consider all the races of man, as forming a single 
species, his range is enormous ; but some separate races, 
as the Americans and Polynesians, have very wide 
ranges. It is a well-known law that widely-ranging 
species are much more variable than species with re- 
stricted ranges ; and the variability of man may with 
more truth be compared with that of widely-ranging 
species, than with that of domesticated animals. 

Not only does variability appear to be induced in 
man and the knver animals by the same general causes, 
but in both the same characters are affected in a closely 
analogous manner. This has been proved in such full 
detail by Godron and Quatrefages, that I need here 
only refer to their works. 13 Monstrosities, w r hich gra- 

13 Godron, ' De l'Espece,' 1859, tom. ii. livre 3. Quatrefages, ' Unite 
de l'Espece Humaine,' 1861. Also Lectures on Anthropology, given 
in the ' Eevue des Cours Scientifiques,' 18G6-1SG8. 



Chap. IV. MANNER OF DEVELOPMENT. 113 

duate into slight variations, are likewise so similar in 
man and the lower animals, that the same classifica- 
tion and the same terms can be used for both, as may 
be seen in Isidore Geoffroy St.-Hilaire's great work. 14 
This is a necessary consequence of the same laws of 
change prevailing throughout the animal kingdom. 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 shewn by all or 
nearly all the individuals of the same species varying 
in the same manner under the same circumstances. 
The effects of the long-continued use or disuse of 
parts. The cohesion of homologous parts. The vari- 
ability of multiple parts. Compensation of growth ; 
but of this law I have found no good instances 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 ; 15 but several are so im- 
portant for us, that they must be treated at consider- 
able length. 

The direct and definite action of changed conditions. — 
This is a most perplexing subject. It- cannot be denied 

14 ' Hist. Gen. et Part, des Anomalies de 1' Organisation,' in three 
volumes, torn. i. 1832. 

15 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 ' Do l'lnfluence 
des Milieux, &c.' He lays much stress on the nature of the soil. 

VOL I. I 



114 THE DESCENT OF MAN. Part I. 

that changed conditions produce some effect, and occa- 
sionally a considerable effect, on organisms of all kinds ; 
and it seems at first probable that if sufficient time 
were allowed this would be the invariable result. But 
I have failed to obtain clear evidence in favour of this 
conclusion ; 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 condi- 
tions induce an almost indefinite amount of fluctuating 
variability, by which the whole organisation is rendered 
in some degree plastic. 

In the United States, above 1,000,000 soldiers, who 
served in the late war, were measured, and the States 
in which they were born and reared recorded. 16 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 band, it is certain that with 
sailors, their manner of life delays growth, as shewn " by 
" the great difference between the statures of soldiers and 
" sailors at the ages of 17 and 18 years." Mr. B. A. Gould 
endeavoured to ascertain the nature of the influences 
which thus act on stature ; but he arrived only at nega- 
tive results, namely, that they did not relate to climate, 
the elevation of the land, soil, nor even " in any con- 
u trolling degree " to the abundance or need of the com- 



1(5 ' Investigations in Military and Anthrop. Statistics,' &c. 1869, by 
B. A. Gould, p. 93, 107, 126, 131, 131. 



CiiAP. IV. MANNER OF DEVELOPMENT. 115 

forts of life. This latter conclusion is directly opposed 
to that arrived at by Yillerme 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, 17 or 
again between the Fuegians on the eastern and western 
shores of their country, where the means of subsistence 
are very different, it is scarcely possible to avoid the 
conclusion that better food and greater comfort do in- 
fluence stature. But the preceding statements shew 
how difficult it is to arrive at any precise result. Dr. 
Beddoe has lately proved that, with the inhabitants of 
Britain, residence in towns and certain occupations 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 vigour." 18 

Whether external conditions produce any other 
direct effect on man is not known. It might have been 
expected that differences of climate would have had a 
marked influence, as the lungs and kidneys are brought 
into fuller activity under a low temperature, and the 
liver and skin under a high one. 19 It was former! v 
thought that the colour of the skin and the character 



17 For the Polynesians, see Pricharcl's ' Physical Hist, of Mankind,' 
vol. v. 1847, p. 145, 283. Also Godron, < De "l'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 Elphin- 
stone's ' History of India,' vol. i. p. 324. 

18 * Memoirs, Anthropolog. Soc.' vol. id. 1867-69, p. 561, 565, 567. 

10 Dr. Brakenridge, ' Theory of Diathesis,' ' Medical Times,' June 19 
and July 17, 1869. 

I 2 



116 THE DESCENT OF MAN. Part I . 

of the hair were determined by 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 Ave 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 evi- 
dence 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 acting 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. 20 Different 
occupations habitually followed lead to changed pro- 
portions in various parts of the body. Thus it was 
clearly ascertained by the United States Commission 21 
that the legs of the sailors employed in the late war 
were longer by 0*217 of an inch than those of the sol- 
diers, 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 



20 I have given authorities for these several statements in my 'Varia- 
tion of Animals under Domestication,' vol. ii. p. 297-300. Dr. Jaeger, 
" Ueber das Langenwachsthum der Knochen," ' Jenaischen Zeitschrift,' 
B. v. Heft i. 

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



Chap. IV. MANNER OF DEVELOPMENT. 117 

their lesser height. This shortness of the arms is 
apparently due to their greater use, and is an un- 
expected result; but sailors chieily use their arms in 
pulling and not in supporting weights. The girth of 
the neck and the depth of the instep are greater, whilst 
the circumference of the chest, waist, and hips is less in 
sailors than in soldiers. 

Whether the several foresfoins: modifications would 
become hereditary, if the same habits of life were fol- 
lowed during many generations, is not known, but is 
probable. Rengger 22 attributes the thin legs and thick 
arms of the Payaguas Indians to successive generations 
having passed nearly their whole lives in canoes, with 
their lower extremities motionless. Other writers have 
come to a similar conclusion in other analogous cases. 
According to Cranz, 23 who lived for a long time with the 
Esquimaux, " the natives 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 him- 
" self 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 labourers are at birth larger 
than those of the gentry. 24 From the correlation which 
exists, at least in some cases, 25 between the development 
of the extremities and of the jaws, it is possible that 
in those classes which do not labour much with their 
hands and feet, the jaws would be reduced in size from 
this cause. That they are generally -smaller in refined 
and civilised men than in hard-working men or savages, 



22 * S'augetkiere yon Paraguay,' 1830, s. 4. 

23 ' History of Greenland,' Eng. translat. 1767, vol. i. p. 230. 

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

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



118 THE DESCENT OF MAN. Part I. 



26 



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 attached. In infants long before birth, the 
skin on the soles of the feet is thicker than on any 
other part of the body; 27 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 en- 
gravers 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. 28 The inferiority of Europeans, in com- 
parison with savages, in eye-sight and in the other 
senses, is no doubt the accumulated and transmitted 
effect of lessened use during many generations; for 
Eengger 29 states that he has repeatedly observed Euro- 
peans, 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 
no doubt indicates a corresponding difference in the 
dimensions of the organs themselves. Blumenbach has 
also remarked on the large size of the nasal cavities 



26 ( Principles of Biology,' vol. i. p. 455. 

27 Paget, ' Lectures on Surgical Pathology,' vol. ii. 1853, p. 209. 
2S ' The Variation of Animals under Domestication,' vol. i. p. 8. 

29 ' Saugethiere von Paraguay,' s. 8, 10. I have had good oppor- 
tunities 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 
(' Ptevue 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.' 



Chap. IV. MANNER OF DEVELOPMENT. 119 

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. 30 

The Quechua Indians inhabit the lofty plateaux of 
Peru, and Alcide d'Orbismv states 31 that from con- 
tinually breathing a highly rarefied atmosphere they 
have acquired chests and lungs of extraordinary dimen- 
sions. 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 Aymaras, an allied race, living at the 
height of between ten and fifteen thousand feet ; and 
he informs me 32 that they differ conspicuously from the 
men of all other races seen by him, in the circum- 
ference 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 those of Negroes. The legs are 
likewise shorter, and they present this remarkable pecu- 
liarity, that in every Aymara 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 



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

31 Quoted by Prichard, ' Eesearches into the Phys. Hist, of Man- 
kind,' vol. v. p. 463. 

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



120 THE DESCENT OF MAN". Part I. 

time, the femora to the tibiae were as 244 to 230 ; and 
in three Negroes as 258 to 241. The humerus is like- 
wise shorter relatively to the forearm. 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 acclimatised to their 
cold and lofty abode, that when formerly carried down 
by the Spaniards to the low Eastern plains, and when 
now tempted down by high wages to the gold-washings, 
they suffer a frightful rate of mortality. Nevertheless 
Mr. Forbes found a few pure families which had sur- 
vived during two generations ; and he observed that 
they still inherited their characteristic peculiarities. 
But it was manifest, even without measurement, that 
these peculiarities had all decreased ; and on measure- 
ment their bodies were found not to be so much elon- 
gated as those of the men on the high plateau ; whilst 
their femora had become somewhat lengthened, as had 
their tibiae but in a less degree. The actual measure- 
ments may be seen by consulting Mr. Forbes' memoir. 
From these valuable observations, there can, I think, 
be no doubt that residence during many generations at 
a great elevation tends, both directly and indirectly, to 
induce inherited modifications in the proportions of the 
body. 33 

Although man may not have been much modified 
during the latter stages of his existence through the 



33 Dr. Wilckens (' Landwirthschaft. Wochenblatt,' No. 10, 1S69) 
has lately published an interesting essay shewing how domestic 
animals, which live in mountainous regions, have their frames 
modified. 



Chap IV. MANNER OF DEVELOPMENT. 121 

increased or decreased use of parts, the facts now given 
shew 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 
bodv. 

Arrests of Development — Arrested development differs 
from arrested growth, as parts in the former state con- 
tinue to grow whilst still retaining their early condition. 
Various monstrosities come under this head, and some 
are known to be occasionally inherited, as a cleft-palate. 
It will suffice for our purpose to refer to the arrested 
brain-development of microcephalous idiots, as described 
in Vogt's great memoir. 34 Their skulls are smaller, and 
the convolutions of the brain are less complex than in 
normal men. The frontal sinus, or the projection over 
the eye-brows, is largely developed, and the jaws are 
prognathous to an " ejfrayant " 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 tip 
furniture or trees. We are thus reminded of the delight 

34 'Mernoire sur les Microcephales,' 18(37, p. 50, 125, l^lYl^.isi- 
198. /^ i* -*>' 

i! LI B 



<p\ 



~ Cs. 



322 THE DESCENT OF MAX. Part I. 

shewn 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. 

Reversion. — Many of the cases to be here given 
might have been introduced under the last heading. 
Whenever 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, we may in one sense consider it as a case 
of reversion. The lower members in a group give us 
some idea how the common progenitor of the group was 
probably constructed ; and it is hardly credible that a 
part arrested at an early phase of embryonic develop- 
ment should be enabled to continue growing so as ulti- 
mately to perform its proper function, unless it had 
acquired this power of continued growth 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 
reversion. There are other cases which come more 
strictly under our present heading of reversion. Certain 
structures, regularly occurring in the lower members of 
the group to which man belongs, occasionally make 
their appearance in him, though not found in the normal 
human embryo; or, if present in the normal human 
embryo, they become developed in an abnormal manner, 
though this manner of development is proper to the 
low r er members of the same group. These remarks will 
be rendered clearer by the following illustrations. 

In various mammals the uterus graduates from a 
double organ with two distinct orifices and tw r o passages, 
as in the marsupials, into a single organ, showing no 
signs of doubleness except a slight internal fold, as in 



Chap. IV. MANNER OF DEVELOPMENT. 12 



o 



the higher apes and man. The rodents exhibit a per- 
fect series of gradations between these two extreme 
states. In all mammals the uterus is developed from 
two simple primitive tubes, the inferior portions of 
which form the cornua; and it is in the words of 
Dr. Farce "by the coalescence 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 or 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 lost, or, as it were, absorbed into the 
"body of the uterus." The angles of the uterus are 
still produced into cornua, even so high in the scale as 
in the lower apes, and their allies the lemurs. 

Now in women anomalous cases are not very infre- 
quent, 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 con- 
" centrative 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. 35 No such stage is passed 
through during the ordinary development of the embryo, 
and it is difficult to believe, though perhaps not im- 
possible, that the two simple, minute, primitive tubes 
could know how (if such an expression may be used) to 



35 See Dr. A. Farre's well-known article in the ' Cyclop, of Anat. 
and Phys.' vol. v. 1859, p. 642. Owen ' Anatomy of Vertebrates,' vol. 
iii. 1868. p. 687. Prof. Turner in ' Edinburgh Medical Journal,' Feb. 
1865. 



124 THE DESCENT OF MAN. Part I. 

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 develop- 
ment, 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 long- 
lost dormant structures are called back into existence, 
might serve as the guide for the full development of 
the organ, even after the lapse of an enormous interval 
of time. 

Professor Canestrini, 36 after discussing the foregoing 
and various analogous cases, arrives at the same con- 
clusion as that just given. He adduces, as another 
instance, the malar bone, which, in some of the Quad- 
rumana and other mammals, normally consists of two 
portions. This is its condition in the two-months-old 
human foetus ; and thus it sometimes remains, through 
arrested development, in man when adult, more especially 
in the lower prognathous races. Hence Canestrini con- 
cludes that some ancient progenitor of man must have 
possessed this bone normally divided into two portions, 
which subsequently 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 
mammals, it consists of two pieces separated by a dis- 
tinct suture. This suture occasionally persists, more 
or less distinctly, in man after maturity, and more fre- 



36 'Armuario della Soc. dei Naturalisti in Modena,' 1867, p. 83. 
Prof. Canestrini gives extracts on this subject from various authorities. 
Laurillard remarks, that as he has found a complete similarity in the 
form, proportions, and connexion of the two malar bones in several 
human subjects and in certain apes, he cannot consider this disposition 
of the parts as simply accidental. 



Chap. IV. MANNEK OF DEVELOPMENT. 125 

qnently 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 ana- 
logons 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 cha- 
racters 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 progenitors. 

Various other anomalies in man, more or less analo- 
gous with the foregoing, have been advanced by dif- 
ferent authors 37 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 struc- 
tures normally present. 38 



37 A whole series of cases is given by Isid. Geoffroy St.-Hilaire, 
' Hist, des Anomalies,' torn. iii. p. 437. 

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 generally 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 ano.ther 
woman with supernumerary mammas. But Prof. Preyer (' Der Kampf 
nm das Dasein.' 1869, s. 45 ) states that mammas erratics have been 
known to occur in other situations, even on the back ; so that the force 
of my argument is greatly weakened or perhaps quite destroyed. 

With much hesitation I, in the same work (vol. ii. p. 12), attributed 
the frequent cases of polydactylism in men to reversion. I was partly 
led to this through Prof. Owen's statement, that some of the Ichthy- 
opterygia possess more than five digits, and therefore, as I supposed, had 
retained a primordial condition ; but after reading Prof. Gegenbaur's 
paper (' Jenaischen Zeitschrift,' B. v. Heft 3, s. 341 ), who is the highest 
authority in Europe on such a point, and who disputes Owen's con- 
clusion, I see that it is extremely doubtful whether supernumerary 
digits can thus be accounted for. It was the fact that such digits not 
only frequently occur and are strongly inherited, but have the power 
of regrowth after amputation, like the normal digits of the lower verte- 



126 THE DESCENT OF MAX. Part I. 

In man the canine teeth are perfectly efficient instru- 
ments for mastication. But their true canine character, 
as Owen 39 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, especially 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 con- 
cerned, be considered as rudimentary. In every large 
collection of human skulls some may be found, as 
Hackel 40 observes, with the canine teeth projecting con- 
siderably beyond the others in the same manner, but 
in a less degree, as in the anthropomorphous apes. In 
these cases, open spaces between the teeth in the one 
jaw are left for the reception of the canines belonging 
to the opposite jaw. An interspace of this kind in a 
Kaffir skull, figured by Wagner, is surprisingly wide. 41 
Considering how few ancient skulls have been examined 
in comparison with recent skulls, it is an interesting 
fact that in at least three cases the canines project 
largely ; and in the Naulette jaw they are spoken of as 



enormous. 42 



brata, that chiefly led me to the above conclusion. This extraordinary 
fact of their regrowth remains inexplicable, if the belief in reversion to 
some extremely remote progenitor must be rejected. I cannot, how- 
ever, follow Prof. Gegenbaur in supposing that additional digits could 
not reappear through reversion, without at the same time other parts of 
the skeleton being simultaneously and similarly modified ; for single 
chaiacters often reappear through reversion. 

39 ' Anatomy of Vertebrates,' vol. iii. 18G8, p. 323. 

40 ' Generelle Morphologic,' 1866, B. ii. s. civ. 

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

42 C. Carter Blake, on a jaw from La Nanlette, ' Anthiopolog. 
Review,' 1867, p. 295. Schaaffhausen, ibid. 18C8, p. 426. 



Chap. IV. MANNER OF DEVELOPMENT. 127 

The males alone of the anthropomorphous apes 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 that women sometimes have, as I have been assured, 
considerably projecting canines, is no serious objection 
to the belief that their occasional great development 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 progenitors having 
been provided with these formidable weapons, will pro- 
bably 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 ,!l (thus named by Sir C. Bell) 43 so as 
to expose them readv for action, like a dog prepared to 
fight. 

Many muscles are occasionally developed in man, 
which are proper to the Quadrumana or other mam- 
mals. Professor Vlacovich 44 examined fortv male sub- 
jects, 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. Out of thirty female 
subjects this muscle was developed on both sides in only 
two, 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 principle of the descent of mairfrom some lower 
form, its presence can be understood ; for it has been 
detected in several of the lower animals, and in all of 



43 I 



The Anatomy of Expression,' 1844, p. 110, 131. 
44 Quoted by Prof. Canestrini iu the ' Annuario,' &e., 1 SG7, p. 90. 



128 THE DESCENT OF MAN. Part 1. 

these it serves exclusively to aid the male in the act 
of reproduction. 

Mr. J. Wood, in his valuable series of papers, 45 has 
minutely described a vast number of muscular varia- 
tions in man, which resemble normal structures in the 
lower animals. Looking only to the muscles which 
closely resemble those regularly present in our nearest 
allies, the Quaclrumana, they are too numerous to be 
here even specified. 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 clavi- 
cular" such as is found in all kinds of apes, and which 
is said to occur in about one out of sixty human sub- 
jects. 46 Again, this man had "a special abductor of 
" the metatarsal bone of the fifth digit, such as Pro- 
" fessor Huxley and Mr. Flower have shewn to exist 
" uniformly in the higher and lower apes." The hands 
and arms of man are eminently characteristic structures, 
but their muscles are extremely liable to vary, so as to 
resemble the corresponding muscles in the lower ani- 
mals. 47 Such resemblances are either complete and per- 

45 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. Eoyal Soc. vol. xiv. 1805, p. 379-384 ; 
vol. xv. 1866, p. 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 shewn 
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 Lemuroidea. 

46 Prof. Macalister in 'Proc. R. Irish Academy,' vol. x. 1868, p. 124. 

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



Chap. IV. MANNER OF DEVELOPMENT. 129 

feet or imperfect, yet in tins latter case manifestly of 
a transitional nature. Certain variations are more com- 
mon in man, and others in woman, without our being 
able to assign any reason. Mr. Wood, after describing 
numerous cases, makes the following pregnant 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 anatomy." 48 

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, in 
no less than seven of his muscles, certain apes, if there 
had been no genetic connection between them. On the 
other hand, if man is descended from some ape-like 
creature, no valid reason can be assigned why certain 
muscles should not suddenly reappear after an interval of 
many thousand generations, in the same manner as with 
horses, asses, and mules, dark-coloured stripes suddenly 
reappear on the legs and shoulders, after an interval of 
hundreds, or more probably thousands, of generations. 

These various cases of reversion are so closely related 



48 The Eev. Dr. Hatighton, 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 shews 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 downwards 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, 
admitting even the possibility of either of his first propositions. Prof. 
Macalister 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 musole in the Quadrumana. 

VOL. I. K 



130 THE DESCENT OF MAN. Part I. 

to those of rudimentary organs given in the first chapter, 
that many of them might have been indifferently intro- 
duced in either chapter. 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 rudimental in man, 
as the os coccyx in both sexes and the ruanimse 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, as well 
as the strictly rudimentary, structures reveal the de- 
scent of man from some lower form in an unmistakeable 
manner. 

Correlated Variation. — In man, as in the lower ani- 
mals, 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 par- 
ticularly 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 colour of the skin and 
hair, colour and constitution, are more or less correlated. 49 
Professor Schaaffhausen first drew attention to the rela- 



49 The authorities for these several statements are given in my 
Variation of Animals under Domestication,' vol. ii. p. 320-335. 



Chap. IV. MANNEK OF DEVELOPMENT. 131 

tion apparently existing between a muscular frame and 
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 provi- 
sionally called spontaneous, for they appear, owing to our 
ignorance, to arise without any exciting cause. It can, 
however, be shewn that such variations, whether con- 
sisting of slight individual differences, or of strongly- 
marked and abrupt deviations of structure, depend 
much more on the constitution of the organism than 
on the nature of the conditions to which it has been 
subjected. 5 



50 



Piate of Increase. — Civilised populations have been 
known under favourable conditions, as in the United 
States, to double their number in twenty -five years ; 
and according to a calculation by Euler, this might 
occur in a little over twelve years. 51 At the former rate 
the present population of the United States, namely, 
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 continued 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 subsist- 
ence is easy and there is plenty of room. If such means 
were suddenly doubled in Great Britain, our number 
would be quickly doubled. With civilised nations the 



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

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

K 2 



132 THE DESCENT OF MAN. Part I. 

above primary check acts chiefly by restraining mar- 
riages. The greater death-rate of infants in the poorest 
classes is also very important; as well as the greater 
mortality at all ages, and from various diseases, of the 
inhabitants of crowded and miserable houses. The 
effects of severe epidemics and wars are soon counter- 
balanced, and more than counterbalanced, in nations 
placed under favourable conditions. Emigration also 
comes in aid as a temporary check, but not to any 
great extent with the extremely poor classes. 

There is reason to suspect, as Malthus has remarked, 
that the reproductive power is actually less in barbarous 
than in civilised 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 
believed, by the women suckling their infants for a pro- 
longed period; but it is highly probable that savages, 
who often suffer much hardship, and who do not obtain so 
much nutritious food as civilised men, would be actually 
less prolific. I have shewn in a former work, 52 that 
all our domesticated quadrupeds and birds, and all 
our cultivated plants, are more fertile than the corre- 
sponding species in a state of nature. It is no valid 
objection to this conclusion that animals suddenly 
supplied with an excess of food, or when rendered very 
fat, and that most plants when suddenly removed from 
very poor to very rich soil, are rendered more or less 
sterile. We might, therefore, expect that civilised 
men, who in one sense are hifrhlv domesticated, would 



52 ' Variation of Animals and Plants under Domestication,' vol. ii. 
p. 111-113, 163. 



Chap. IV. MANNER OF DEVELOPMENT. 133 

be more prolific than wild men. Tt is also probable 
that the increased fertility of civilised 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. 53 

Notwithstanding- that savages appear to be less pro- 
lific than civilised people, they would no doubt rapidly 
increase if their numbers were not by some means 
rigidly kept down. The Santali, or hill-tribes of India, 
have recently afforded a good illustration of this fact ; 
for they have increased, as shewn by Mr. Hunter, 54 
at an extraordinary rate since vaccination has been 
introduced, other pestilences mitigated, and war sternly 
repressed. 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 prudential 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 with which to purchase her from her 
parents. With savages the difficulty of obtaining sub- 
sistence occasionally limits their number in a much 
more direct manner than with civilised 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 sto- 
machs and emaciated limbs after and during famines. 
They are then, also, compelled to wander much about, 
and their infants, as I was assured in Australia, perish 



53 Mr. Sedgwick, ' British and Foreign Medico-Clrirurg. Review, ' 
July, 18G3, p. 170. 

54 ' The Annals of Rural Bengal,' by W. W. Hunter, 1868, p. 259. 



134 THE DESCENT OF MAN. Part I. 

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 artificial increase in the supply of food. 
Savages when hardly pressed encroach on each other's 
territories, and war is the result ; but they are indeed 
almost always at war with their neighbours. They are 
liable to many accidents on land and water in their search 
for food ; and in some countries they must 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, namely infanticide, especially of female 
infants, and the habit of procuring abortion. These 
practices now prevail in many quarters of the world, 
and infanticide seems formerly to have prevailed, as 
Mr. M'Lennan 55 has shewn, on a still more extensive 
scale. These practices appear to have originated in 
savages recognising the difficulty, or rather the impos- 
sibility of supporting all the infants 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 savages at the present time. Our early semi- 
human progenitors would not have practised infanticide, 
for the instincts of the lower animals are never so per- 
verted as to lead them regularly to destroy their own 



55 



' Primitive Marriage/ 1865. 



Chap. IV. MANNER OF DEVELOPMENT. 135 

offspring. There would have been no prudential re- 
straint 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 may have been, we cannot say, any more than 
with most other animals. We know that horses and 
cattle, which are not highly prolific animals, when first 
turned loose in South America, increased at an enormous 
rate. The slowest breeder of all known animals, namely 
the elephant, 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 increased ; 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 unfavourable 
seasons, being probably the most important of all. So 
it will have been with the early progenitors of man. 

Natural Selection. — We have now seen that man is 
variable in boclv and mind; and that the variations 
are induced, either directly 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, 56 to the most diversified con- 



56 See some good remarks to this effect by W. Stanley Jevons, " A 
Deduction from Darwin's Theory," ' Nature,' 1869, p. 231. 



136 THE DESCENT OF MAN. Part I. 

ditions. 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. 57 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 deviations 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, 58 to incessant variability. If then the ape-like 
progenitors of man which inhabited any district, espe- 
cially one undergoing some change in its conditions, were 
divided into two equal bodies, the one half which in- 
cluded all the individuals best adapted by their powers 
of movement for gaining subsistence or for defending 
themselves, would on an average survive in greater 
number and procreate more offspring than the other 
and less well endowed half. 

Man in the rudest state in which he now exists is 
the most dominant animal that has ever appeared 
on the earth. He has spread more widely than any 



37 Latham, ' Man and his Migrations,' 1851, p. 135. 

58 Messrs. Murie and Mivart in their " Anatomy of the Lemuroidea" 
(' Transact. Zoolog. Soc.' vol. vii. 1869, p. 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. 



Chap. IV. MANNEK OF DEVELOPMENT. 137 

other highly organised form ; and all others have 
yielded before him. He manifestly owes this immense 
superiority to his intellectual faculties, 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 arbitra- 
ment of the battle for life. Through his powers of in- 
tellect, articulate language has been evolved; and on 
this his wonderful advancement has mainly depended. 
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 on which to fish or cross over to neigh- 
bouring 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 in- 
nocuous. This last discovery, probably the greatest, 
excepting language, ever made by man, dates from 
before the dawn of history. These several inventions, 
by which man in the rudest state has become so pre- 
eminent, are the direct result of the development of 
his powers of observation, memory, curiosity, imagina- 
tion, and reason. I cannot, therefore, understand how 
it is that Mr. Wallace 59 maintains, that " natural selec- 



59 ' Quarterly Review,' April, 18G9, 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 criticised by Prof. 
Claparede, one of the most distinguished zoologists in Europe, in an 
article published in the ' Bibliotheque Universelle,' June, 1S70. The 
remark quoted in my text will surprise every one who has read 
Mr. Wallace's celebrated paper on 'The Origin of Human Paces 
deduced from the Theory of Natural Selection,' originally publishec 
in the ' Anthropological Review,' May, 1864, p. clviii. I cannot h#re^ 
resist quoting a most just remark by Sir J. Lubbock (' Prehis^*^ O 
Times,' 1865, p. 479) in reference to this paper, namely, thay-ifc\x ^j^i 
Wallace, "with characteristic unselfishness, ascribes it (i.e. the iilb&or 

TuJ LIB I 

\t- , ^ 



138 THE DESCENT OF MAX. Part I. 

" tion 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 importance 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 will be discussed in the following chapter. 

Even to hammer with precision is no easy matter, as 
every one who has tried to learn carpentry will admit. 
To throw a stone with as true an aim as can a Fueofian in 
defending himself, or in killing birds, requires the most 
consummate perfection in the correlated action of the 
muscles of the hand, arm, and shoulder, not to mention 
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 coadaptation of 
numerous muscles. 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, 60 remarks, the shaping fragments of 
stone into knives, lances, or arrow-heads, shews " extra- 
" ordinary ability and long practice." We have evidence 
of this in primeval men having practised a division of 
labour ; 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 re- 
ceiving in exchange the produce of the chase. Archaeo- 
logists are convinced that an enormous interval of time 



" natural selection) unreservedly to Mr. Darwin, although, as is well 
" known, he struck out the idea independently, and published it, 
" though not with the same elaboration, at the same time." 

60 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. 



Chap. IV. MANNER OF DEVELOPMENT. 139 

elapsed before our ancestors thought of grinding chipped 
flints into smooth tools. A man-like animal who pos- 
sessed a hand and arm sufficiently perfect to throw a 
stone with precision or to form a flint into a rude tool, 
could, it can hardly be doubted, with sufficient practice 
make almost anything, as far as mechanical skill alone 
is concerned, which a civilised 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 spe- 
cies, musical cadences ; but in man closely similar vocal 
organs have become adapted through the inherited 
effects of use for the utterance of articulate language. 

Turning now to the nearest allies of man, and there- 
fore to the best representatives of our early progenitors, 
we find that the hands in the Quadrumana are con- 
structed on the same general pattern as in us, but are 
far less perfectly adapted for diversified uses. Their 
hands do not serve so well as the feet of a dog for loco- 
motion ; as may be seen in those monkeys which walk 
on the outer margins of the palms, or on the backs of 
their bent fingers, as in the chimpanzee and orang. 16 
Their hands, however, are admirably adapted for climb- 
ing trees. Monkeys seize thin branches or ropes, with 
the thumb on one side and the fingers and palm on 
the other side, in the same manner as we do. They 
can thus also carry 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 sinalL objects with the 
thumb in opposition to the fingers, and no doubt they 
thus extract eggs and the young from the nests of 
birds. American monkeys beat the wild oranges on the 



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



140 THE DESCENT OF MAN. Part I. 

branches until the rind is cracked, and then tear it off 
with the fingers of the two hands. 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. In a state of nature they break open hard 
fruits with the aid of stones. They roll down stones 
or throw them at their enemies ; nevertheless, they 
perform these various actions clumsily, and they are 
quite unable, as I have myself seen, to throw a stone 
with precision. 

It seems to me far from true that because " objects 
" are grasped clumsily " by monkeys, " a much less 
" specialised organ of prehension " would have served 
them 62 as well as their present hands. On the con- 
trary, I see no reason to doubt that a more perfectly 
constructed hand would have been an advantage to them, 
provided, and it is important to note this, that their 
hands had not thus been rendered less well adapted for 
climbing trees. We may suspect that a perfect hand 
would have been disadvantageous for climbing ; as the 
most arboreal monkeys in the world, namely Ateles in 
America and Hylobates in Asia, either have their thumbs 
much reduced in size and even rudimentary, or their 
fingers partially coherent, so that their hands are con- 
verted into mere grasping-hooks. 63 

As soon as some ancient member in the great series 
of the Primates came, owing to a change in its manner 
of procuring subsistence, or to a change in the con- 



62 'Quarterly Review,' April, 1869, p. 392. 

63 In Hylobates syndactylus, as the name expresses, two of the digits 
regularly cohere ; and this, as Mr. Blyth informs me, is occasiorjally 
the case with the digits of H. agilis, lar, and leuciscm. In Colobus the 
thumb is likewise deficient ; these monkeys are strictly arboreal and 
extraordinarily active (Brehni, ' Thierleben,' B. i. s. 50), but whether 
they are better climbers or graspers than the species of the allied 
genera, I do not know. 



Chap. IV. MANNER OF DEVELOPMENT. 141 

ditions of its native country, to live somewhat less on 
trees and more on the ground, its manner of progres- 
sion would have been modified ; and in this case it 
would have had to become either more strictly quad- 
rupedal or bipedal. Baboons frequent hilly and rocky 
districts, and only from necessity climb up high trees ; M 
and they have acquired almost the gait of a clog. 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 the most conspicuous differences between 
him and his nearest allies. 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. As Sir C. Bell 65 
insists " the hand supplies all instruments, and by its 
" correspondence with the intellect gives him universal 
" dominion." But the hands and arms could hardly 
have become perfect enough to have manufactured 
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 long as they were especially well adapted, 
as previously remarked, 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 have become a biped ; but for many actions it is 
almost necessary that both arms and the whole upper 
part of the body should be free ; and he must for this 
end stand firmly on his feet. To gain this great 
advantage, the feet have been rendered flat, and the 
great toe peculiarly modified, though this has entailed 
the loss of the power of prehension. It accords with 



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

65 " The Hand," &c. 4 Bridgewater Treatise,' 1S33, p. 38. 



142 THE DESCENT OF MAN. Part 1. 

the principle of the division of physiological labour, 
which prevails throughout the animal kingdom, 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 prehensile power, as shewn by 
their manner of climbing trees and of using them in 
other ways. 66 

If it be an advantage to man to have his hands and 
arms free and to stand firmly on his feet, of which there 
can be no doubt from his pre-eminent success in the 
battle of life, 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 have defended 
themselves with stones or clubs, or to have attacked 
their prey, or otherwise obtained food. The best con- 
structed individuals would in the long run have succeeded 
best, and have survived 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 reflection) that several kinds 
of apes are now actually in this intermediate condition ; 
and no one doubts that they are on the whole well 
adapted for their conditions of life. Thus the gorilla 



66 H'ackel has an excellent discussion on the steps by which man 
became a biped : ' Naiiirliche Schopfungsgeschichte,' 1868, s. 507. Dr. 
Biichuer (' Conferences sur la The'orie Darwinienne,' 18b'9, p. 135) has 
given good cases of the use of the foot as a prehensile organ by man ; 
also on the manner of progression of the higher apes to which I allude 
in the following paragraph : see also Owen (' Anatomy of Vertebrates,' 
vol. iii. p. 71) on this latter subject. 



Chap. IV. MANNER OF DEVELOPMENT. 143 

runs with a sidelong shambling gait, but more 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, with existing monkeys various grada- 
tions between a form of progression strictly like that of 
a quadruped and that of a biped or man. 

As the progenitors of man became more and more 
erect, with their hands and arms more and more modi- 
fied for prehension and other purposes, with their feet 
and legs at the same time modified for firm support 
and progression, endless other changes of structure 
would have been necessary. The pelvis would have 
had to be made broader, the spine peculiarly curved 
and the head fixed in an altered position, and all these 
changes have been attained by man. Prof. Schaaff- 
hausen 67 maintains that " the powerful mastoid processes 
of the human skull are the result of his erect position ; " 
and these processes are absent in the orangj chim- 
panzee, &c, and are smaller in the gorilla than in man. 
Various other structures might here have been specified, 
which appear connected with man's erect position. It 
is very difficult to decide how far all these correlated 
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 act .and react on each 
other : thus when certain muscles, and the crests of 
bone to which they are attached, become enlarged by 



67 "On the Primitive Form of the Skull," translated in 'Anthropo- 
logical Review,' Oct. 1868, p. 428. Owen (' Anatomy of Vertebrates,' 
vol. ii. 1SUG, p. 551) on the mastoid processes in the higher apes. 



144 THE DESCENT OF MAN. Part I. 

habitual use, this shews that certain actions are 
habitually performed 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 indirect manner to other modifications of 
structure. The early male progenitors 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, they would have used their jaws and teeth less 
and less. In this case, the jaws, together with the 
teeth, would have become reduced in size, as we may 
feel sure from innumerable analogous cases. In a future 
chapter we shall meet with a closely-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 
with their habit of fighting with their incisor teeth and 
hoofs. 

In the adult male anthropomorphous apes, as Riiti- 
meyer, 68 and others have insisted, it is precisely the effect 
which the jaw-muscles by their great development have 
produced on the skull, that causes it to differ so greatly 
in many respects from that of man, and has given to 
it " a truly frightful physiognomy." Therefore as the 
jaws and teeth in the progenitors of man gradually 
become reduced in size, the adult skull would have 
presented nearly the same characters which it offers in 
the young of the anthropomorphous apes, and would 
thus have come to resemble more nearly that of existing 



68 



'Die Grenzen der Thierwelt, eine Betrachtung zu Darwin's 



Lehre,' 1868, s. 51. 



Chap. IV. MANNER OF DEVELOPMENT. 145 

man. A great reduction of the canine teeth in the 
males would almost certainly, as we shall hereafter see, 
have affected through inheritance the teeth of the 
females. 

As the various mental faculties were gradually de- • 
veloped, the brain would almost certainly have become 
larger. No one, I presume, doubts that the large size 
of the brain in man, relatively to his body, in compari- 
son with that of the gorilla or orang, is closely con- 
nected with his higher mental powers. We meet with 
closely analogous facts with insects, in which the cerebral 
ganglia are of extraordinary dimensions in ants; these 
ganglia in all the Hymenoptera being many times larger 
than in the less intelligent orders, such as beetles. 69 
On the other hand, no one supposes that the intellect o 
any two animals or of any two men can be accurately 
gauged bv 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 affections of ants are generally 
known, yet their cerebral ganglia are not so large as the 
quarter of a small pin's head. Under this latter point 
of view, the brain of an ant is one of the most marvellous 
atoms of matter in the world, perhaps more marvellous 
than the brain of man. 

The belief that there exists in man some close relation 
between the size of the brain and the development of 
the intellectual faculties is supported by the comparison 
of the skulls of savage and civilised races, of ancient and 
modern people, and by the analogy of the whole verte- 



6D 



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

VOL. I. l L 



146 THE DESCENT OF MAN. Part I. 

brate series. Dr. J. Barnard Davis has proved 70 by 
many careful measurements, that the mean internal 
capacity of the skull in Europeans is 92*3 cubic inches ; 
in Americans 87*5 ; in Asiatics 87*1 ; and in Australians 
only 81*9 inches. Professor Broca 71 found that skulls 
from graves in Paris of the nineteenth century, were 
larger than those from vaults of the twelfth century, in 
the proportion of 1484 to 1426 ; and Prichard is per- 
suaded that the present inhabitants of Britain have 
"much more capacious brain-cases" than the ancient 
inhabitants. Nevertheless it must be admitted that 
some skulls of very high antiquity, such as the famous 
one of Neanderthal, are well developed and capacious. 
With respect to the lower animals, M. E. Lartet, 72 by com- 
paring the crania of tertiary and recent mammals, be- 
longing to the same groups, has come to the remarkable 
conclusion that the brain is generally larger and the 
convolutions more complex in the more recent form. 
On the other hand I have shewn 73 that the brains of 
domestic rabbits are considerably reduced in bulk, in 
comparison with those of the wild rabbit or hare ; and 
this may be attributed to their having been closely con- 
fined during many generations, so that they have exerted 
but little their intellect, instincts, senses, and voluntary 
movements. 

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 



70 ' Philosophical Transactions,' ] 869, p. 513. 

71 Quoted in C. Vogt's 'Lectures on Man,' En<r. translat. 1864, p. 
88. 90. Prichard, ' Phys. Hist, of Mankind,' vol. i. 1838, p. 305. 

72 ' Comptes Eendus des Seances,' &c. June 1, 1868. 

73 ' The Variation of Animals and Plants under Domestication,' vo 
i. p. 124-129. 



Chap. IV. MANNER OF DEVELOPMENT. 147 

being brought about, the internal pressure of the brain, 
will, also, have influenced the form of the skull; for 
many facts shew how easily the skull is thus affected. 
Ethnologists believe that it is modified by the kind of 
cradle in which infants sleep. Habitual spasms of the 
muscles and a cicatrix from a severe burn have per- 
manently modified the facial bones. In young persons 
whose heads from disease have become fixed either 
sideways or backwards, one of the eyes has changed 
its position, and the bones of the skull have been 
modified ; and this apparently results from the brain 
pressing in a new direction. 74 I have shewn that with 
long-eared rabbits, even so trifling a cause as the lopping 
forward of one ear drags forward on that side almost 
every bone of the skull ; so that the bones on the oppo- 
site sides no longer strictly correspond. Lastly, if any 
animal were to increase or diminish 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 observations on domestic 
rabbits, some kinds of which have become very much 
larger than the wild animal, whilst others have retained 
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 by finding that in all 
these rabbits the skull had become elongated or dolicho- 



74 Schaaff hausen gives from Blumenbach and Busch, the cases of the 
spasms and cicatrix, in ' Anthropolog. Review,' Oct. 1868, p. 420. Dr. 
Jarrold (' Anthropologia,' 1808, p. 115, 116) adduces from Camper and 
from bis own observations, cases of the modification of the skull from 
the head being fixed in an unnatural position. He believes that cer- 
tain trades, such as that of a shoemaker, by causing the head to be 
habitually held forward, makes the forehead more rounded and 
prominent. 

L _ 



\& 



148 THE DESCENT OF MAN. Part I. 

cephalic ; 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 only 3*15 and the 
latter 4*3 inches in length. 75 One of the most marked 
distinctions in different races of man is that the skull 
in some is elongated, and in others rounded ; and here 
the explanation suggested by the case of the rabbits 
may partially hold good ; for Welcker finds that short 
" men incline more to brachycephaly, and tall men to 
dolichocephaly ; " 76 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 to a certain ex- 
tent understand the means through which the great 
size and more or less rounded form of the skull has 
been acquired by man ; and these are characters emi- 
nently distinctive of him in comparison with the lower 
animals. 

Another most conspicuous difference between man and 
the lower animals is the nakedness of his skin. Whales 
and dolphins (Cetacea), dugongs (Sirenia) and the hip- 
popotamus 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 and otters. Elephants and rhino- 
ceroses 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 
appear as if the existing species of both genera had lost 



75 'Variation of Animals,' &c, vol. i. p. 117 on the elongation of the 
skull; p. 119, on the effect of the lopping of one ear. 

76 Quoted by Schaaflhausun, in ' Anthropolog. Review,' Oct. 1868, 
p. 419. 



Chap. IV. MANNER OF DEVELOPMENT. 149 

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 77 than those 
on the lowlands. May we then infer that man became 
divested of hair from having aboriginally inhabited some 
tropical land ? The fact of the hair being 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, favours this inference, assuming that the hair was 
lost before man became erect ; lor 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. In this respect man 
agrees with the great majority of quadrupeds, which 
generally have their upper and exposed surfaces more 
thickly clothed than the lower surface. Nevertheless, 
the fact that the other members of the order of Pri- 
mates, to which man belongs, although inhabiting vari- 
ous hot regions, are well clothed with hair, generally 
thickest on the upper surface, 78 is strongly opposed 
to the supposition that man became naked through the 
action of the sun. I am inclined to believe, as we 
shall see under sexual selection, that man, or rather 
primarily woman, became divested of hair for orna- 
mental purposes ; and according to this belief it is not 



77 Owen, l Anatomy of Vertebrates,' vol. iii. p. 619. 

78 Isidore Geoffroy St.-Hilaire remarks (' Hi§t. Nat. Generale,' torn, 
ii. 1859, p. 215-217; on the head of man being covered with long hair ; 
also on the upper surfaces 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. 



150 THE DESCENT OF MAN. Part I. 

surprising that man should differ so greatly in hairi- 
ness from all his lower brethren, for characters gained 
through sexual selection often differ in closely-related 
forms to an extraordinary degree. 

According to a popular impression, the absence of a 
tail is eminently distinctive of man ; but as those apes 
which come nearest to man are destitute of this organ, 
its disappearance does not especially concern us. Never- 
theless it may be well to own that no explanation, as 
far as I am aware, has ever been given of the loss of the 
tail by certain apes and man. Its loss, however, is not 
surprising, for it sometimes differs remarkably in length 
in species of the same genera: thus in some species 
of Macacus the tail is longer than the whole body, con- 
sisting of twenty-four vertebrae ; in others it consists of a 
scarcely visible stump, containing only three or four 
vertebrae. In some kinds of baboons there are twenty- 
five, whilst in the mandrill there are ten verv small 
stunted caudal vertebrae, or, according to Cuvier, 79 some- 
times only five. This great diversity in the structure and 
length of the tail in animals belonging to the same genera, 
and following nearly the same habits of life, renders it 
probable that the tail is not of much importance to 
them ; and if so, we might have expected that it would 
sometimes have become more or less rudimentary, in 
accordance with what we incessantly see with other struc- 
tures. The tail almost always tapers towards the end 
whether it be long or short; and this, I presume, re- 
sults from the atrophy, through disuse, of the terminal 
muscles together with their arteries and nerves, lead- 
ing to the atrophy of the terminal bones. With respect 



79 Mr. St. George Mivart, ' Proc. Zoolog. Soc' 1865, p. 562, 583. 
Dr. J. E. Gray, 'Cat. Brit. Mus. : Skeletons.' Owen, 'Anatomy of 
Vertebrates,' vol. ii. p. 517. Isidore Geoffrov, 'Hist. Nat. Ge'n.' tom. 
li p. 244. 



Chap. IV. MANNER OF DEVELOPMENT. 151 

to the os coccyx, which in man and the higher apes 
manifestly consists of the few basal and tapering seg- 
ments of an ordinary tail, I have heard it asked how 
could these have become completely embedded within 
the body ; but there is no difficulty in this respect, 
for in many monkeys the basal segments of the true 
tail are thus embedded. For instance, Mr. Murie in- 
forms me that in the skeleton of a not fall-grown 
Macacus inomatus, he counted nine or ten caudal ver- 
tebrae, which altogether were only 1*8 inch in length. 
Of these the three basal ones appeared to have been 
embedded ; the remainder forming the free part of the 
tail, which was only one inch in length, and half an 
inch in diameter. Here, then, the three embedded 
caudal vertebras plainly correspond with the /our coal- 
esced vertebras of the human os coccyx. 

I have now endeavoured to shew that some of the 
most distinctive characters of man have in all proba- 
bility been acquired, either directly, or more commonly 
indirectly, through natural selection. We should bear 
in mind that modifications in structure or constitution, 
which are of no service to an organism in adapt- 
ing it to its habits of life, to the food which it con- 
sumes, or passively to the surrounding conditions, can- 
not have been thus acquired. We must not, however, 
be too confident in deciding what modifications are of 
service to each being : we should remember how little 
we know about the use of many parts, or what changes 
in the blood or tissues may serve to jit an organism for 
a new climate or some new kind of food. Nor must 
we forget the principle of correlation, by which, as 
Isidore Geoffroy has shewn in the case of man, many 
strange deviations of structure are tied together. Inde- 
pendently of correlation, a change in one part often leads 



152 THE DESCENT OF MAN. Part I. 

through the increased 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 colour in the 
plumage of parrots when fed on certain fishes, or in- 
oculated with the poison of toads ; 80 for we can thus 
see that the fluids of the system, if altered for some 
special purpose, might induce other strange 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 very 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 
JSTageli on plants, and the remarks by various authors 
with respect to animals, more especially those recently 
made by Professor Broca, that in the earlier editions of 
my * Origin of Species ' I probably 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. I had not formerly sufficiently considered 
the existence of many structures which appear to be, 
as far as we can judge, 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 shew that species had not been separately 
created, and secondly, that natural selection had been 
the chief agent of change, though largely aided by the 



80 ' The Variation of Animals and Plants under Domestication.' vol. 
ii. p. 280, 282. 



Chap. IV. MANNER OF DEVELOPMENT. 153 

inherited effects of habit, and slightly by the direct 
action of the surrounding conditions. Nevertheless I 
was not able to annul • the influence of my former 
belief, then widely prevalent, that each species had 
been purposely created ; and this led to my tacitly 
assuming that every detail of structure, excepting rudi- 
ments, was of some special, though unrecognised, ser- 
vice. Any one with this assumption in his mind would 
naturally extend the action of natural selection, either 
during past or present times, too far. Some of those 
who admit the principle of evolution, but reject natural 
selection, seem to forget, when criticising 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 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. 

That all organic beings, including man, present many 
modifications of structure which are of no service to 
them at present, nor have been formerly, is, as I can 
now see, probable. We know not what produces the 
numberless slight differences between the individuals of 
each species, for reversion only carries the problem a few 
steps backwards ; but each peculiarity must have had 
its own efficient cause. If these causes, whatever they 
may be, were to act more uniformly and energetically 
during a lengthened period (and no reason can be 
assigned why this should not sometimes occur), the 
result would probably be not mere slight individual 
differences, but well-marked, constant modifications. 
Modifications which are in no way beneficial cannot 
have been kept unifornf through natural selection, 
though any which were injurious would have been thus 
eliminated. Uniformity of character would, however, 



154 THE DESCENT OF MAN. Part I. 

naturally follow from the assumed uniformity of the 
exciting causes, and likewise from the free intercros- 
sing of many individuals. The same organism might 
acquire in this manner during successive periods suc- 
cessive modifications, and these would be transmitted 
in a nearly uniform state as long as the exciting causes 
remained the same and there was free intercrossing. 
With 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 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 individual differences or slight variations, so 
no doubt were the early progenitors of man ; the varia- 
tions being then as now induced by the same general 
causes, and governed by the same general and complex 
laws. As all animals tend to multiply beyond their 
means of subsistence, so it must have been with the 
progenitors of man ; and this will inevitably have led 
to a struggle for existence and to natural selection. 
This latter process will have been greatly aided by 
the inherited effects of the increased use of parts; 
these two processes incessantly reacting on each other. 
It appears, also, as we shall hereafter see, that various 
unimportant characters have been acquired by man 
through sexual selection. An unexplained residuum 
of change, perhaps a large one, 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 



Chap. IV. MANNER OF DEVELOPMENT. 155 

the ape-like progenitors of man, probably lived in 
society. With strictly social animals, natural selection 
sometimes acts indirectly on the individual, through 
the preservation of variations which are beneficial only 
to the community. A community including a large 
number of well-endowed individuals increases in number 
and is victorious over other and less well-endowed com- 
munities ; although each separate member may gain no 
advantage over the other members of tire same com- 
munity. With associated insects many remarkable 
structures, which are of little or no service to the indi- 
vidual or its own offspring, such as the pollen-collecting 
apparatus, or the sting of the worker-bee, or the 
great jaws of soldier- ants, have been thus acquired. 
With the higher social animals, I am not aware that 
any structure has been modified solely for the good of 
the community, though some are of secondary service 
to it. For instance, the horns of ruminants and the 
great canine teeth of baboons appear to have been 
acquired by the males as weapons for sexual strife, but 
they are used in defence of the herd or troop. In 
resard to certain mental faculties the case, as we shall 
see in the following chapter, is wholly different ; for 
these faculties have been chiefly, or even exclusively, 
gained for the benefit of the community; the indi- 
viduals composing the community being at the same 
time indirectly benefited. 

It has often been objected to such views as the fore- 
going, that man is one of the most helpless and defence- 
less creatures in the world ; and that during his early 
and less well-developed condition he would have been 
still more helpless. The Duke of Argyll, for instance, 
insists 81 that " the human frame lias diverged from 

81 ' Primeval Man,' 1869, p. 60. 



156 THE DESCENT OF MAN. Part I. 

" 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 defence, the 
little strength of man, his small speed in running, and 
his slight power of smell, by which to discover food or 
to avoid danger. To these deficiencies there might 
have been added the still more serious loss of the power 
of quickly climbing trees, so as to escape from enemies. 
Seeing that the unclothed Fuegians can exist under 
their wretched, climate, the loss of hair would not 
have been a great injury to primeval man, if he inha- 
bited a warm country. When we compare defenceless 
man with the apes, many of which are provided with 
formidable canine teeth, w r e must remember that these 
in their fully-developed condition are possessed by the 
males alone, being chiefly used by them for fighting 
with their rivals ; yet the females which are not thus 
provided, are able to survive. 

In regard to bodily size or strength, we do not know 
whether man is descended from some comparatively 
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, in comparison with his progenitors. 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 
probably, though not necessarily, have failed to become 
social ; and this would most effectually have checked 
the acquirement by man of his higher mental quali- 
ties, such as sympathy and the love of his fellow- 
creatures. Hence it might have been an immense 



Chap. IV. MANNER OF DEVELOPMENT. 157 

advantage to man to have sprung from some com- 
paratively weak creature. 

The slight corporeal strength of man, his little speed, 
his want of natural weapons, &c, are more than coun- 
terbalanced, firstly by his intellectual powers, through 
which he has, whilst still remaining in a barbarous state, 
formed for himself weapons, tools, &c, and secondly by 
his social qualities which lead him to give aid to his 
fellow-men and to receive it in return. No country 
in the world abounds in a greater degree with dan- 
gerous beasts than Southern Africa; no country pre- 
sents more fearful physical hardships than the Arctic 
regions ; yet one of the puniest races, namely, the 
Bushmen, maintain themselves in Southern Africa, as 
do the dwarfed Esquimaux in the Arctic regions. The 
early progenitors of man were, no doubt, inferior 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, whilst 
they gradually lost their brute-like powers, such as 
climbing trees, &c, they at the same time advanced 
in intellect. But granting that the progenitors of man 
were far more helpless and defenceless than any existing 
savages, if they had inhabited some warm continent 
or large island, such as Australia or New Guinea, or 
Borneo (the latter island being now tenanted by the 
orang), they would not have been exposed to any special 
danger. In an area as large as one of these islands, 
the competition between tribe and tribe would have 
been sufficient, under favourable conditions, to have 
raised man, through the survival of the fittest, combined 
with the inherited effects of habit, to his present high 
position in the organic scale. 



158 THE DESCENT OF MAN. Part I. 



CHAPTEK V. 

On the Development of the Intellectual and Moral 
Faculties during Primeval and Civilised Times. 

The 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 
selection as affecting civilised nations — Evidence that civilised 
nations were once barbarous. 

The subjects to be discussed in this chapter are of 
the highest interest, but are treated by me in a most 
imperfect and fragmentary manner. Mr. Wallace, 
in an admirable paper before referred to, 1 argues that 
man after he had partially acquired those intellectual 
and moral faculties which distinguish him from the 
lower animals, would have been but little liable to 
have had his bodily structure modified through natural 
selection or any other means. For man is enabled 
through his mental faculties "to keep with an un- 
" changed body in harmony with the changing universe." 
He has great power of adapting his habits to new 
conditions of life. He invents weapons, tools and 
various stratagems, by which he procures food and 
defends 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 practised 
some subdivision of labour. 



i < 



Anthropological Review,' May, 18G4, p. clviii. 



Chap. V. INTELLECTUAL FACULTIES. 159 

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, in 
order to defend themselves from new enemies ; or they 
must be reduced in size so as to escape detection and 
danger. 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. Wal- 
lace has with justice insisted, in relation to the intel- 
lectual and moral faculties 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 per- 
fected or advanced through natural selection. Of the 
high importance of the intellectual faculties there can 
be no doubt, for man mainly owes to them his pre- 
eminent 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, partly on the physical nature of the country, 
but in a much higher degree on the arts which are there 
practised. As a tribe increases and is victorious, it is 
often still further increased by the absorption of other 
tribes. 2 The stature and strength of the men of a tribe 

2 After a time the members or tribes which are absorbed into another 
tribe assume, as Mr. Maine remarks (' Ancient Law,' 1SG1, p. 131), that 
they are the co-descendants of the same ancestors. 



160 THE DESCENT OF MAN. Part I. 

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 supplanted by a more powerful and, 
judging from their sword- handles, larger-handed race ; 3 
but their success was probably due in a much higher 
degree to their superiority in the arts. 

All that we know about savages, or may infer from 
their traditions and from old monuments, the history 
of which is quite forgotten by the present inhabitants, 
shew that from the remotest times successful tribes have 
supplanted other tribes. Kelics of extinct or forgotten 
tribes have been discovered throughout the civilised 
regions of the earth, on the wild plains of America, and 
on the isolated islands in the Pacific Ocean. At the 
present day civilised 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 intellectual faculties have been 
gradually perfected through natural selection ; and this 
conclusion is sufficient for our purpose. Undoubtedly 
it would have been very interesting to have traced 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 
permit the attempt. 

It deserves notice that as soon as the progenitors of 
man became social (and this probably occurred at a 
very early period), the advancement of the intellectual 
faculties will have been aided and modified in an 
important manner, of which we see only traces in 



3 Morlot, ' Soc. Vaud. Sc Nat. 1 i860, p. 294. 



Chap. V. INTELLECTUAL FACULTIES. 161 

the lower animals, namely, through the principle 
of imitation, together with reason and experience. 
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, shews that animals learn 
by experience, and imitate each others' caution. 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 defence, 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 better chance of the birth of 
other superior and inventive members. If such men 
left children to inherit their mental 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 they left no children, the 
tribe would still include their blood-relations ; and it has 
been ascertained by agriculturists 4 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 have become social, thev must have 



4 I have given instances in my ' Variation of Animals under Domes- 
tication/ vol. ii. p. 196. 

VOL. I. M 



162 THE DESCENT OF MAN. Part I. 

acquired the same instinctive feelings which impel other 
animals to live in a body ; and they no doubt exhi- 
bited 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 
would have warned each other of danger, and have 
given mutual aid in attack or defence. 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 the one tribe included (other circumstances being 
equal) a greater number of courageous, sympathetic, 
and faithful members, who were always ready to warn 
each other of danger, to aid and defend each other, this 
tribe would without doubt succeed best 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 undisciplined hordes follows chiefly from the 
confidence which each man feels in his comrades. 
Obedience, as Mr. Bagehot has well shewn, 5 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 possessing the above qualities in a high de- 
gree 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 



5 See a remarkable series of articles on Physics and Politics in the 
Fortnightly Review,' Nov. 1SU7 ; April 1, 1SGS; July 1, 1869. 



Chap. Y. MOKAL FACULTIES. 16 



30 



o 



and still more highly endowed tribe. 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 excellence raised? It is 
extremely doubtful whether the offspring of the more 
sympathetic and benevolent parents, or of those which 
were the most faithful to their comrades, would be 
reared in greater number than the children of selfish 
and treacherous parents of the same tribe. He who 
was ready to sacrifice 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 number than other men. 
Therefore it seems scarcely possible (bearing in mind 
that we are not here speaking of one tribe being vic- 
torious over another) that the number of men gifted 
with such virtues, or that the standard of their excel- 
lence, could be increased through natural selection, that 
is, by the survival of the fittest. 

Although the circumstances which lead to an increase 
in the number of men 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 from 
experience 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 actions certainly 
strengthens the feeling of sympathy, which gives the 

M 2 



164 THE DESCENT OF MAN. Part I. 

first impulse to benevolent actions. Habits, moreover, 
followed during many generations probably tend to be 
inherited. 

But there is another and much more powerful sti- 
mulus to the development of the social virtues, namely, 
the praise and the blame of our fellow-men. The love 
of approbation and the dread of infamy, as well as the 
bestowal of praise or blame, are primarily clue, as Ave 
have seen in the third chapter, to the instinct of sym- 
pathy; and this instinct no doubt was originally acquired, 
like all the other social instincts, through natural selec- 
tion. At how early a period the progenitors of man, in 
the course of their development, became capable of feel- 
ing and being impelled by the praise or blame of their 
fellow-creatures, we cannot, of course, say. But it appears 
that even dogs appreciate 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 which they take of their personal 
appearance and decorations ; for unless they regarded 
the opinion of their comrades, such habits would be 
senseless. 

Thev certainlv feel shame at the breach of some of 
their lesser rules ; but how far they experience remorse 
is doubtful. I was at first surprised that I could not re- 
collect any recorded instances of this feeling in savages ; 
and Sir J. Lubbock 6 states that he knows of none. 
But if we banish from our minds all cases given in 
novels and plays and in death-bed confessions made 
to priests, I doubt whether many of us have actually 
witnessed remorse; though we may have often seen 
shame and contrition for smaller offences. Remorse is 



' Origin of Civilisation,' 1870, p. 265. 



Chai\ V. MOKAL FACULTIES. 165 

a deeply hidden feeling. It is incredible 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, 7 would not feel remorse in his 
inmost soul, though he might conceal it, if he had failed 
in a duty which he held sacred. 

We may therefore conclude that primeval man, at a 
very remote period, would have been influenced by the 
praise and blame of his fellows. It is obvious, that the 
members of the same tribe w r ould 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 possible to exaggerate the impor- 
tance 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 exer- 
cise the noble feeling of admiration. He might thus 
do far more good to his tribe than by begetting 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 virtues, 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 third chapter. Ultimately a 
highly complex sentiment, having its first origin in the 



7 Mr. Wallace gives cases in his ' Contributions to the Theory of 
Natural Selection/ 1870, p. 354. 



166 THE DESCENT OF MAN. Part I. 

social instincts, largely guided by the approbation of 
our fellow-men, ruled by reason, self-interest, and in 
later times by deep religious feelings, confirmed by 
instruction and habit, all combined, constitute our moral 
sense or conscience. 

It must not be forgotten that although a high stand- 
ard 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 advancement in the 
standard of morality and an increase in the number 
of well-endowed men will certainly give an immense 
advantage to one tribe over another. There can be no 
doubt that 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 give aid to each other and to sacrifice them- 
selves 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 sup- 
planted other tribes ; and as morality is one element 
in their success, the standard of morality and the num- 
ber of well-endowed men will thus everywhere 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 civilisation. 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 the normal rule 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, 
Mr. Maine, 8 "the greatest part of mankind has never 



8 'Ancient Law,' 1861, p. 22. For Mr. Bagehot's remarks, 'Fort- 
nightly Review,' April 1, 1868, p. 452. 



Chap. V. CIVILISED NATIONS. 167 

" shewn a particle of desire that its civil institutions 
" should be improved." Progress seems to depend on 
many concurrent favourable conditions, far too complex 
to be followed out. But it has often been remarked, that 
a cool climate from leading to industry and the various 
arts has been highly favourable, or even indispensable 
for this end. The Esquimaux, pressed by hard necessity, 
have succeeded in many ingenious inventions, but their 
climate has been too severe for continued progress. 
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 barbarous inhabitants of Tierra 
del Fuego, it struck me that the possession of some 
property, a fixed abode, and the union of many families 
under a chief, were the indispensable requisites for 
civilisation. Such habits almost necessitate the culti- 
vation of the ground ; and the first steps in cultivation 
would probably result, as I have elsewhere shewn, 9 from 
some such accident as the seeds of a fruit-tree falling 
on a heap of refuse and producing an unusually fine 
variety. The problem, however, of the first advance of 
savages towards civilisation is at present much too diffi- 
cult to be solved. 

Natural Selection as affecting Civilised Nations. — In 
the last and present chapters I have considered the 
advancement of man from a former semi-human con- 
dition to his present state as a barbarian. But some 
remarks on the agencv of natural selection on civilised 
nations may be here worth adding. This subject has 
been ably discussed by Mr. W. R. Greg, 10 and previously 

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

10 ' Fraser's Magazine,' Sept. 1868, p. 353. This article seems to 
have struck many persons, and has given rise to two remarkable essays 



168 THE DESCENT OF MAN. Part I. 

by Mr. Wallace and Mr. Galton. 11 Most of my remarks 
are taken from these three authors. With savages, the 
weak in body or mind are soon eliminated ; and those 
that survive commonly exhibit a vigorous state of 
health. We civilised 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 formerly have succumbed to small-pox. Thus 
the weak members of civilised 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 
degeneration of a domestic race ; but excepting in the 
case of man himself, hardly any one is so ignorant as 
to allow his worst animals to breed. 

The aid which we feel impelled to give to the help- 
less is mainly an incidental result of the instinct of 
sympathy, which was originally 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, if 
so urged by hard reason, without deterioration in the 



and a rejoinder in the ' Spectator,' Oct. 3rd and I7th 1868. It has 
also been discussed in the ' Q. Journal of Science,' 1869, p. 152, and by 
Mr. Lawson Tait in the 'Dublin Q. Journal of Medical Science,' Feb. 
1869, and by Mr. E. Kay Lankester in his ' Comparative Longevity/ 
1S70, p. 128. Similar views appeared previously in the 'Australasian,' 
July 13, 1867. I have borrowed ideas from several of these writers. 

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



Chap. V. CIVILISED NATIONS. 169 

noblest part of our nature. The surgeon may harden 
himself whilst performing 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 a certain 
and great present evil. Hence we must bear without 
complaining 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 the 
weaker and inferior members of society not marrying 
so freely as the sound ; and this check might be inde- 
finitely increased, though this is more to be hoped for 
than expected, by the weak in body or mind refraining 
from marriage. 

In all civilised countries man accumulates property 
and bequeaths it to his children. So that the children 
in the same country do not by any means start fair in 
the race for success. But this is far from an unmixed 
evil ; for without the accumulation of capital the arts 
could not progress ; and it is chiefly through their power 
that the civilised races have extended, and are now 
everywhere extending, their range, so as to take the place 
of the lower races. Nor does the moderate accumulation 
of wealth interfere with the process of selection. When 
a poor man becomes rich, his children enter trades or 
professions in which there is struggle enough, so that 
the able in body and mind succeed best. The presence 
of a body of well-instructed men, who have not to 
labour 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 acl vantages. No doubt wealth when 
very great tends to convert men into useless drones, bu^\\3^ 
their number is never large ; and some degree of elimi- 




170 THE DESCENT OF MAN. Part I. 

nation here occurs, as we daily see rich men, who happen 
to be fools or profligate, squandering away all their 
wealth. 

Primogeniture with entailed estates is a more direct 
evil, though it may formerly have been a great advan- 
tage by the creation of a dominant class, and any 
government is better than anarchy. The eldest sons, 
though they may be weak in body or mind, generally 
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 elsewhere, the relations of civilised 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 con- 
sequences, such as they may be, of the continued pre- 
servation 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 shewn, 12 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 supe- 
riority of any kind. 

Although civilisation thus checks in many ways the 
action of natural selection, it apparently favours, by 
means of improved food and the freedom from occa- 
sional hardships, the better development of the body. 
This may be inferred from civilised men having been 



12 



'Hereditary Genius,' 1S70, p. 132-140. 



Chap. V. CIVILISED NATIONS. 171 

found, wherever compared, to be physically stronger than 
savages. They appear also to have equal powers of 
endurance, 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. 13 

We will now look to the intellectual faculties alone. 
If in each grade of society the members were divided 
into two equal bodies, the one including the intel- 
lectually superior and the other the inferior, 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 labour, a very small 
one. Hence in civilised 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 
counterbalanced 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 fore- 
going, that the most eminent men who have ever lived 
have left no offspring to inherit their great intellect. 
Mr. Gal ton says, 14 " 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, how- 
" ever, shewn that men of eminence are by no means so." 



13 See the fifth and sixth columns, compiled from good authorities, 
in the table given in Mr. E. K. Lankester's ' Comparative Longevity,' 
1870 r p. 115. 

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



172 THE DESCENT OF MAN. Part I. 

Great lawgivers, the founders of beneficent religions, 
great philosophers 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 pre- 
servation of strongly-marked and rare anomalies, that 
leads to the advancement of a species. 15 So it will be 
with the intellectual faculties, namely from the some- 
what more able men in each grade of society succeeding 
rather better than the less able, and consequently in- 
creasing 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, as shewn by 
Mr. Galton, that prodigies of genius will appear some- 
what more frequently than before. 

In regard to the moral qualities, some elimination of 
the worst dispositions is always in progress even in the 
most civilised nations. Malefactors are executed, or 
imprisoned for long periods, so that they cannot freely 
transmit their bad qualities. Melancholic and insane 
persons are confined, or commit suicide. Violent and 
quarrelsome men often come to a bloody end. Kestless 
men who will not follow any steady occupation — and 
this relic of barbarism is a great check to civilisation 16 — 
emigrate to newly- sett led countries, where they prove 
useful pioneers. Intemperance is so highly destructive, 
that the expectation of life of the intemperate, at the 
age, for instance, of thirty, is only 13 -8 years ; whilst for 
the rural labourers of England at the same a^e it is 



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

16 'Hereditary Genius,' 1870, p. 347. 



Chap. V. CIVILISED NATIONS. 173 

4059 years. 17 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 unim- 
portant element towards success. This especially holds 
good with injurious characters which tend to reappear 
through reversion, such as blackness in sheep ; and 
with mankind some of the worst dispositions, which 
occasionally without 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 recognised 
in the common expression that such men are the black 
sheep of the family. 

With civilised nations, as far as an advanced stand- 
ard of morality, and an increased number of fairly 
well-endowed men are concerned, natural selection ap- 
parently 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, namely, the approbation of our fellow-men — 
the strengthening of our sympathies by habit — example 
and imitation — reason — experience and even self-inte- 
rest — instruction during youth, and religious feelings. 

A most important obstacle in civilised countries to 
an increase in the number of men of a superior class has 
been strongly urged by Mr. Greg and Mr. Galton, 18 



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

18 ' Fraser'.i Magazine,' Sept. 1868, p. 358. 'Macmillan's Magazine,' 
Aug. 1805, p. 318. The Eev. F. W. Farrar (' Fraser's Mag.,' Aug. 1870, 
p. 261) tahes a different view. 



174 THE DESCENT OF MAN. Paet I. 

namely, the fact that the very poor and reckless, who 
are often degraded by vice, almost id variably 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 shewn by Dr. Duncan, 19 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 generally virtuous 
members. Or as Mr. Greg puts the case : " The care- 
" less, squalid, unaspiring Irishman multiplies like 
" rabbits : the frugal, foreseeing, self-respecting, am- 
" bitious 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 remained. 
" In the eternal ' struggle for existence,' it would be 
" the inferior and less favoured 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 

19 "On the Laws of the Fertility of Women," in * Transact. Eoyal 
Soc.' Edinburgh, vol. xxiv. p. 287. See, also, Mr. Galton, ' Hereditary 
Genius,' p. 352-357, for observations to the above effect. 



Chap. V. CIVILISED NATIONS. 175 

from a high rate of mortality, and the extremely pro- 
fligate 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, 20 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 cleath- 
" rate is almost exactly double that of the rural districts." 
As these returns include both the rich and the poor, no 
doubt more than double the number of births would be 
requisite to keep up the number of the very poor inha- 
bitants 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," 21 
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 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. 22 A similar law was proved to 

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

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

22 Dr. Farr, ibid. The quotations given below are extracted from 
the same striking paper. 



176 THE DESCENT OF MAN. Part I. 

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. 23 Dr. Stark remarks on this, " Bachelorhood is 
" more destructive to life than the most unwholesome 
u 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, 
profligate, and criminal classes, whose duration of life 
is low, do not commonly marry ; and it must like- 
wise 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 ao'ed married men still have a considerable advan- 
tage 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. There is another remarkable circum- 
stance 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 mor- 
tality; but Dr. Fan* attributes this to the poverty and 



- z I have taken the mean of the quinquennial means, given in 'The 
Tenth Annual Keport of Births, Deaths, &c, in Scotland,' 1867. The 
quotation from Dr. Stark is copied from an article in the * Daily News,' 
Oct. 17th, 1S68, which Dr. Farr considers very carefully written. 



Chap. V. CIVILISED NATIONS. 177 

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 unmar- 
ried men, which seems to be a general law, " is mainly 
" due to the constant elimination of imperfect types, and 
" to the skilful selection of the finest individuals out of 
" each successive generation;" the selection relating only 
to the marriage state, and acting on all corporeal, in- 
tellectual, and moral qualities. We may, therefore, 
infer that sound and good men who out of prudence 
remain for a time unmarried do not sutler a high rate 
of mortal it v. 

If the various checks specified in the two last para- 
graphs, and perhaps others as yet unknown, do not 
prevent the reckless, the vicious and otherwise inferior 
members of society from increasing at a quicker rate 
than the better class of men, the nation will retro- 
grade, as has occurred too often in the history of the 
world. We must remember that progress is no invari- 
able rule. It is most difficult to say why one civilised 
nation rises, becomes more powerful, and spreads more 
widely, than another ; or why the same nation progresses 
more at one time than at another. We can only say 
that it depends on an increase in the actual number 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, 
except so far as vigour of body leads to vigour of mind, 
appears to have little influence. 

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, 24 ought to have 

24 See the ingenious and original argument on this subject by Mr. 
Galton, 'Hereditary Genius,' p. 310-342. 

VOL. I. N 



178 THE DESCENT OF MAN. Part I. 

risen, if the power of natural selection were real, still 
higher in the scale, increased in number, and stocked 
the whole of Europe. Here we have the tacit assump- 
tion, 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 concurrent favourable cir- 
cumstances. Natural selection acts only in a tentative 
manner. Individuals and races may have acquired 
certain indisputable advantages, and yet have perished 
from failing in other characters. The Greeks may have 
retrograded from a want of 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." 25 The western nations 
of Europe, who now so immeasurably surpass their 
former savage progenitors and stand at the summit of 
civilisation, owe little or none of their superiority to 
direct inheritance from the old Greeks; though they 
owe much to the written works of this 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 
this early period, as Mr. Galton 26 has remarked, almost 
all the men of a gentle nature, those given to medi- 
tation or culture of the mind, had no refuge except in 
the bosom of the Church which demanded celibacy ; 



25 Mr. Greg, ' Fraser's Magazine,' Sept. 1868, p. 357. 

26 'Hereditary Genius,' 1870, p. 357-359. The Eev. F. H. Farrar 
(' Fraser'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) called attention, in a striking passage, to the evil influence of 
the Holy Inquisition in having lowered, through selection, the general 
standard of intelligence in Europe. 



Chap. V. CIVILISED NATIONS. 179 

and this could hardly fail to have had a deteriorating 
influence on each successive generation. During this 
same period the Holy Inquisition selected with extreme 
care the freest and boldest men in order to burn or 
imprison 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, though 
no doubt counterbalanced to a certain, perhaps large 
extent in other ways, is incalculable ; nevertheless, 
Europe has progressed at an unparalleled rate. 

The remarkable success of the English as colonists 
over other European nations, which is well illustrated by 
comparing the progress of the Canadians of English and 
French extraction, has been ascribed to their " daring 
" and persistent energy ; " 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 
people, are the results of natural selection ; the more 
energetic, restless, and courageous men from all parts 
of Europe having emigrated during the last ten or 
twelve generations to that great country, and having there 
succeeded best. 27 Looking to the distant future, I do 
not think that the Rev. Mr. Zincke takes an exaggerated 
view when he says : 28 " All other series of events — as 
" that which 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 subsidiarv to ... . the 
" great stream of Anglo-Saxon emigration to the west." 



27 Mr. Gal ton, • Macmillan's Magazine,' August, 1865, p. 325. See, 
also, ' Nature,' " On Darwinism and National Life," Dec. 1869, p. 184. 

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

N 2 



180 THE DESCENT OF MAN. Part I. 

Obscure as is the problem of the advance of civilisation, 
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 favoured nations. 

Natural selection follows from the struggle for exist- 
ence ; and this from a rapid rate of increase. It is 
impossible not bitterly to regret, but whether wisely 
is another question, the rate at which man tends to 
increase ; for this leads in barbarous tribes to infan- 
ticide and many other evils, and in civilised nations to 
abject poverty, celibacy, and to the late marriages of 
the prudent. But as man suffers from the same physical 
evils with 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 to natural 
selection, assuredlv he would never have attained to 
the rank of manhood. When we see in many parts 
of the world enormous areas of the most fertile land 
peopled by a few wandering savages, but which are 
capable of supporting numerous happy homes, it might 
be argued that the struggle for existence had not been 
sufficiently severe to force man upwards to his highest 
standard. Judoino- from all that we know of man and 
the lower animals, there has always been sufficient 
variability in the intellectual and moral faculties, for 
their steady advancement through natural selection. 
No doubt such advancement demands many favourable 
concurrent circumstances ; but it may well be doubted 
whether the most favourable would have sufficed, had 
not the rate of increase been rapid, and the consequent 
struggle for existence severe to an extreme degree. 

On tlie evidence that all civilised nations were once bar- 
barous, — As we have had to consider the steps by which 



Ciiap. V. CIVILISED NATIONS. 181 

some semi-bum an creature has been gradually raised to 
the rank of man in his most perfect state, the present 
subject cannot be quite passed over. But it has been 
treated in so full and admirable a manner by Sir J. 
Lubbock, 39 Mr. Tylor, Mr. M'Lennan, and others, that 
1 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 favour of the belief that man came into the world 
as a civilised being and that all savages have since 
undergone degradation, seem to me weak in comparison 
with those advanced on the other side. Many nations, 
no doubt, have fallen away in civilisation, and some 
may have lapsed into utter barbarism, though on this 
latter head I have not met with any 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 civilised nations are the de- 
scendants 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 independently able to raise 
themselves a few steps in the scale of civilisation, 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, for instance, of the art of 
enumeration, which, as Mr. Tylor clearly shews by the 
words still used in some places, originated in counting 

29 'On tke Origin of Civilisation,' ' Proc. Ethnological Soc' Nov. 
26, 1867. 

29 'Primeval Man,' 1869. 



182 THE DESCENT OF MAN. Part I. 

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, "which 
after reaching to the number V., change into VI., &c, 
when the other hand no doubt was used. So again, 
" when we speak of three-score and ten, we are count- 
" ing by the vigesimal system, each score thus ideally 
" made, standing for 20 — for ' one man ' as a Mexican 
" or Carib would put it." 31 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, as letters are rudiments of 
pictorial representations. It is hardly possible to read 
Mr. M'Lennan's work 32 and not admit that almost all 
civilised nations still retain some traces of such rude 
habits as the forcible capture of wives. What ancient 
nation, as the same author asks, can be named that was 
originally monogamous ? The primitive idea of justice, 
as shewn by the law of battle and other customs of 
which traces 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. Lub- 
bock has shewn that some savages have recently im- 
proved a little in some of their simpler arts. From the 



31 'Koyal Institution of Great Britain,' March 15, 1867. Also, 
' Researches into the Early History of Mankind,' 1865. 

32 'Primitive Marriage,' 1865. See, likewise, an excellent article, 
evidently by the same author, in the ' North British Review,' July, 
1869. Aho, 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. Schaaffhausen (' Anthropolog. 
Review,' Oct. 1869, p. 373) remarks on "the vestiges of human sacri- 
" fices found both in Homer and the Old Testament." 



Chap. V. CIVILISED NATIONS. 183 

extremely curious account which he gives of the weapons, 
tools, and arts, used or practised by savages in various 
parts of the world, it cannot be doubted that these have 
nearly all been independent discoveries, excepting per 
haps the art of making fire. 33 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 any foreign source ; 34 
many native plants were there cultivated, and a few 
native animals domesticated. We should bear in mind 
that a wandering crew from some semi-civilised land, 
if washed to the shores of America, would not, judging 
from the small influence of most missionaries, have pro- 
duced 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 existing 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 many countries, which 
include nearly the wdiole civilised world, were once in a 
barbarous condition. To believe that man was abori- 



33 Sir J. Lubbock, 'Prehistoric Times,' 2nd edit. 1869, chap. xv. and 
xvi. et passim. 

34 Dr. F. Midler has made some good remarks to this effect in the 
'Keise der Novara : Anthropolog. Theil,' Abtheil. iii. 1868, s. 127. 



184: THE DESCENT OF MAN. Part 1. 

ginally civilised and then suffered utter degradation in 
so many regions, is to take a pitiably low view of 
hum an 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. 



Chap. VI. AFFINITIES AND GENEALOGY. 185 



CHAPTEE VI. 

On the Affinities axd 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 genealogy of man, as inferred, firstly from his affinities and 
secondly from his structure — 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 naturalists maintain, and although we must grant 
that the difference between them is immense in mental 
power, yet the facts given in the previous chapters 
declare, as it appears to me, in the plainest manner, 
that man is descended from some lower form, notwith- 
standing 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 tends to multiply at so rapid a rate that his off- 
spring are necessarily exposed to a struggle for existence, 
and consequently to natural selection. He has given 
rise to many races, some of which are so different that 
they have often been ranked by naturalists as distinct 
species. His body is constructed on the same homo- 
logical plan as that of other mammals, independently 
of the uses to which the several parts may be put. He 



186 THE DESCENT OF MAN. Part I. 

passes through the same phases of ernbryological de- 
velopment. He retains many rudimentary and useless 
structures, which no doubt were once serviceable. Cha- 
racters occasionally make their re-appearance in him, 
which we have every reason to believe were possessed by 
his early progenitors. If the origin of man had 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 mammals 
of some unknown and lower form. 

Some naturalists, from being deeply impressed with 
the mental 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. 1 Spiritual powers cannot be com- 
pared or classed by the naturalist ; but he may endea- 
vour to shew, 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 undoubt- 
edly belong to the same class. The difference is here 
greater, though of a somewhat different kind, than 
that between man and the highest mammal. The 
female coccus, whilst young, attaches itself by its pro- 
boscis to a plant ; sucks the sap but never moves again ; 
is fertilised and lays eggs ; and this is its whole history. 
On the other hand, to describe the habits and mental 



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



Chap. VI. AFFINITIES AND GENEALOGY. 187 

powers of a female ant, would require, as Pierre Huber 
has shewn, a large volume; I may, however, briefly 
specify a few points. Ants communicate information 
to each other, and several unite for the same work, 
or games of play. They recognise their fellow-ants 
after months of absence. They build great edifices, 
keep them clean, close the doors in the evening, and 
post sentries. They make roads, and even tunnels 
under rivers. 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. 2 They go out to battle in regular 
bands, and freely sacrifice their lives for the common 
weal. They emigrate in accordance with a precon- 
certed plan. They capture slaves. They keep Aphides 
as milch-cows. 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 them in distinct classes, much less in distinct 
kingdoms. No doubt this interval is bridged over by 
the intermediate mental powers of many other insects ; 
and this is not the case with man and the higher apes. 
But we have every reason to believe that breaks in the 
series are simply the result of many forms having be- 
come 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 marsupials and the monotremata; 
so that he makes man as distinct from all other mam- 



2 See the very interesting article, " L'lnstinct cliez les Insectes," by 
M. George Pouchet, ' Revue des Deux Mondes,' Feb. 1870, p. 682. 



188 THE DESCENT OF MAN. Part I. 

. inals 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 judg- 
ment, and therefore need not here be further con- 
sidered. 

We can understand why a classification founded on 
any single character or organ — even an organ so won- 
derfully 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 
thoroughly artificial. 3 Classifications may, of course, be 
based on any character whatever, as on size, colour, 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, genealcgical in arrangement, — that is, the 
co-descendants of the same form must be kept together 
in one group, separate 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 — will be expressed by such 
terms as genera, families, orders, and classes. As we 
have no record of the lines of descent, these lines can 
be discovered only by observing the degrees of re- 
semblance between the beings which are to be classed. 
For this object numerous points of resemblance are of 
much more importance than the amount of similarity 
or dissimilarity in a few points. If two languages 
were found to resemble each other in a multitude of 



3 Westwood, ' Modern Class, of Insects,' vol. ii. 1840, p. S7. 



Chap. VI. AFFINITIES AND GENEALOGY. 189 

words and points of construction, they would be uni- 
versally recognised 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 con- 
sist of adaptations to similar habits of life : two animals 
may, for instance, 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 resemblances in unimportant 
structures, in useless and rudimentary organs, and in 
parts not as yet fully developed or functionally active, 
are by far the most serviceable for classification ; 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 modifi- 
cation 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 con- 
ditions) be liable to further variations of the same kind ; 
and these, if beneficial, would be preserved, and thus 
continuallv augmented. In manv cases the continued 
development of a part, for instance, of the beak of a 
bird, or of the teeth of a mammal, would not be advan- 
tageous to the species for gaining its food, or for any 
other object; but with man we can see no definite limit, 
as far as advantage is concerned, to the continued de- 
velopment of the brain and mental faculties. Therefore 
in determining the position of man. in the natural or 
genealogical system, the extreme development of his 
brain ought not to outweigh a multitude of resem- 



190 THE DESCENT OF MAX. Part I. 

blances in other less important or quite unimportant 
points. 

The greater number of naturalists who have taken 
into consideration 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. 
liecently many of our best naturalists have recurred to 
the view first propounded by Linnaeus, 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 if, in 
the first place, we bear in mind the remarks just 
made on the comparatively small importance for classi- 
fication of the great development of the brain in man ; 
bearing, also, in mind that the strongly-marked differ- 
ences between the skulls of man and the Quadrumana 
(lately insisted upon by 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 
every system, from that of Cuvier to the most recent 
one by Mr. Flower, 4 seals are ranked as a mere familv 



4 ' Proc. Zoolog. Soc' 1869, p. 4. 



Chap. VI. AFFINITIES AND GENEALOGY. 191 

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 philosopher, Prof. Huxley, has 
fully discussed this subject, 5 and has come to the con- 
clusion that man in all parts of his organisation 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 volume I brought forward 
various facts, shewing how closely man agrees in con- 
stitution with the higher mammals ; and this agreement, 
no doubt, depends on our close similarity 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 stimulants, and the similar effects thus produced, 
as w r ell as by various drugs ; and other such facts. 

As small unimportant points of resemblance between 
man and the higher apes 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 the features are manifestly the 
same in man and the Quadrumana; and the various 
emotions are displayed 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, 
durino: which the corners of the mouth are drawn back- 



5 « 



Evidence as to Man's Place in Nature,' 1SG3, p. 70, et passim. 



192 THE DESCENT OF MAX. Part I. 

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 Sem- 
nopitheeus nasica is carried to a ridiculous extreme. 

The faces of many monkeys are ornamented with 
beards, whiskers, or moustaches. The hair on the head 
grows to a great length in some species of Semno- 
pithecus ; 6 and in the Bonnet monkey (Macacus 
radiatiis) it radiates from a point on the crown, with a 
parting down the middle, as in man. It is commonly 
said that the forehead gives to man his noble and intel- 
lectual appearance ; but the thick hair on the head of 
the Bonnet monkey terminates abruptly downwards, 
and is succeeded by such short and fine hair, or down, 
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 7 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 Hylobates, and even to some few 
American monkeys. But in Hylobates agUis the hair 



6 Isid. Geoffroy, ' Hist. Nat. Gen.' torn. ii. 1859, p. 217. 

7 " Ueher die Richtung der Haare," &c, Miillei-'s ' Arcliiv fur Anat. 
und Phys.' 1837, s. 51. 



Chap. VI. AFFINITIES AND GENEALOGY. 193 

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 and its direction on the back 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 remarks that the con- 
vergence of the hair towards the elbow on the arms 
of the orang (whose habits he has so carefully studied) 
serves to throw off the rain, when, as is the custom 
of this animal, the arms are bent, with the hands 
clasped round a branch or over its own head. We 
should, however, bear in mind that the attitude of an 
animal may perhaps be in part determined by the 
direction of the hair ; and not the direction of the hair 
by the attitude. If the above explanation is correct in 
the case of the orang, the hair on our fore-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 impossible 
to study the figures given by Eschricht of the arrange- 
ment 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 between the arrangement 

VOL. I. O 



1 94 THE DESCENT OF MAN. Part I. 

of the hair on the limbs, and the course of the medullary- 
arteries. 8 

It must not be supposed that the resemblances be- 
tween man and certain apes in the above and many 
other points — such as in having a naked forehead, 
long tresses on the head, &c. — are all necessarily the 
result of unbroken inheritance from a common pro- 
genitor thus characterised, or of subsequent reversion. 
Many of these resemblances are more probably due 
to analogous variation, which follows, as I have else- 
where attempted to shew, 9 from co-descended organisms 
having a similar constitution and having been acted 
on by similar causes inducing variability. 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 inheritance ; but not 
certainly so, as some very distinct American monkeys 
are thus characterised. The same remark is applicable 
to the tailless condition of man ; for the tail is absent 
in all the anthropomorphous apes. Nevertheless this 
character cannot with certainty be attributed to inheri- 
tance, as the tail, though not absent, is rudimentary 
in several other Old World and in some New World 
species, and is quite absent in several species belonging 
to the allied group of Lemurs. 

Although, as we have now seen, man has no just right 
to form a separate Order for his own reception, he may 



8 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. Esch- 
richt, ibid, s. 46, 55, 61. Owen, ' Anat. of Vertebrates,' vol. iii. p. 619. 
Wallace, ' Contributions to the Theory of Natural Selection,' 1870, p. 
344. 

9 'Origin of Species,' 5th edit. 1869, p. 194. 'The Variation of 
Animals and Plants under Domestication,' vol. ii. 1868, p. 348. 



Chap. VI. AFFINITIES AND GENEALOGY. 195 

perhaps claim a distinct Sub-order or Family. Prof. 
Huxley, in liis last work, 10 divides the Primates into 
three Sub-orders ; namely, the Anthropidae with man 
alone, the Simiadse including monkeys of all kinds, and 
the Lemuridaa 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 
chiefly to his mental faculties. Nevertheless, under 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 source, 
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 modified as to deserve 
to rank as a distinct Sab-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 lines. 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 
undergone ; and how much to close resemblance in 
numerous unimportant points, as indicating the lines of 
descent or genealogy. The former alternative is the 
most obvious, and perhaps the safest, though the latter 
appears the most correct as giving a truly natural 
classification. 

To form a judgment on this head, with reference 
to man we must glance at the classification of the 



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

o 2 



19(3 THE DESCENT OF MAN. Part I. 

Siniiadse. This family is divided by almost all natura- 
lists into the Catarhine group, or Old World monkeys, 
all of which are characterised (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 characterised by 
differently-constructed nostrils and by having six pre- 
molars 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 Catarhines in any characters, excepting in a few 
of not much importance and apparently of an adaptive 
nature. Therefore it would be against all probability 
to suppose that some ancient New World species had 
varied, and had thus produced a man-like creature with 
all the distinctive characters proper to the Old World 
division ; losing at the same time all its own distinctive 
characters. There can consequently hardly be a doubt 
that man is an offshoot from the Old World Simian stem ; 
and that under a genealogical point of view, he must 
be classed with the Catarhine division. 11 

The anthropomorphous apes, namely the gorilla, 
chimpanzee, orang, and hylobates, are separated as a 
distinct sub-group from the other Old World monkeys 
by most naturalists. I am aware that Gratiolet, relying 
on the structure of the brain, does not admit the exist- 



11 This is nearly the same classification as that provisionally adopted 
by Mr. St. George Mivart (' Transact. Philosoph. Soc.' 1867, p. 300), 
who, after separating the Lemuridoe, divides the remainder of the 
Primates into the Hominidaj, the Simiadae answering to the Catarhines, 
the Cebidae, and the Hapalidse, — these two latter groups answering to 
the Plat vrl tines. 



Chap. VI. AFFINITIES AND GENEALOGY. 197 

ence of this sub-group, and no doubt it is a broken 
one ; tbus the orang, as Mr. St. G, Mivart remarks, 12 
" is one of the most peculiar and aberrant forms to be 
" found in the Order." The remaining, non-anthropo- 
morphous, Old World monkeys, are again divided by 
some naturalists into two or three smaller sub-groups ; 
the genus Semnopithecus, with its peculiar sacculated 
stomach, being the type of one such sub-group. But 
it appears from M. Gaudry's wonderful discoveries in 
Attica, that during the Miocene period a form existed 
there, which connected Semnopithecus and Macacus; 
and this probably illustrates the manner in which the 
other and higher groups were once blended together. 

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 Catarhine 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 a member of one of the other lower sub-groups 
should, through the law of analogous variation, have 
given rise to a man-like creature, resembling the higher 
anthropomorphous apes in so many respects. No 
doubt man, in comparison with most of his allies, has 
undergone an extraordinary amount of modification, 
chiefly in consequence of his greatly developed brain 
and erect position ; nevertheless we should bear in 
mind that he " is but one of several- exceptional forms 
" of Primates." 13 

Every naturalist, who believes in the principle of 



12 < Transact. Zoolog. Soc.' vol. vi. 1867, p. 214. 

13 Mr. St. G. Mivart, ' Transact. Phil. Soc' 18G7, p. 410. 



198 THE DESCENT OF MAN. Part I. 

evolution, will grant that the two main divisions of the 
Simiadse, namely the Catarhine and Platyrhine mon- 
keys, 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 incipient genera would have already begun 
to indicate by their diverging characters the future 
distinctive marks of the Catarhine and Platyrhine divi- 
sions. Hence the members of this supposed ancient 
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 ^reatlv from each 
other in the form of their muzzles, 14 and to an extra- 
ordinary degree in their dentition. 

The Catarhine and Platyrhine monkeys agree in 
a multitude of characters, as is shewn by their unques- 
tionably 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 an ancient form which possessed 
many characters common to the Catarhine and Platy- 
rhine monkeys, and others in an intermediate condition, 
and some few perhaps distinct from those now present 
in either group, w r ould undoubtedly have been ranked, 
if seen by a naturalist, as an aue or monkey. And as 
man under a genealogical puint of view belongs to the 
Catarhine or Old World stock, we must conclude, how- 



14 Messrs. Murie and Mivart on the Lenmroidea, 'Transact. Zoolug. 
Soc.' vol. vii. 1869, p. 5. 



Chap. VI. AFFINITIES AND GENEALOGY. 199 

ever much the conclusion may revolt our pride, that 
our early progenitors would have been properly thus 
designated. 15 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 
resembled, 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 shews that they 
inhabited the Old World ; but not Australia nor any 
oceanic island, as we may infer from the laws of geogra- 
phical distribution. 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 w r as 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 an ape 
nearly as large as a man, namely the Dryopithecus 
of Lartet, which was closely allied to the anthropo- 
morphous Hylobates, existed in Europe during the 
Upper Miocene period ; and since so remote a period 
the earth has certainly undergone many great revo- 
lutions, and there has been ample time for migration 
on the largest scale. 



15 H'ackel has come to this same conclusion. See ' Ueher die Ent- 
stehung des Menschengeschlechts,' in Virchow's ' Sammlung. gemein. 
wissen. Vortrage,' 18G8, s. 61. Also his 'Naturliche Schopfungs- 
geschichte,' 1868, in which he gives in detail his views on the geuea- 
logy of man. 



200 THE DESCENT OF MAN. Part I. 

At the period and place, whenever and wherever it 
may have been, when man first lost his hairy covering, 
he probably inhabited a hot country; and this would 
have been favourable for a 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 this may have occurred 
at an epoch as remote as the Eocene period ; for the 
higher apes had diverged from the lower apes as 
early as the Upper Miocene period, as shewn by the 
existence of the Dryopithecus. We are also quite 
ignorant at how rapid a rate organisms, whether high 
or low in the scale, may under favourable circumstances 
be modified : we know, 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 
within the same period some of the co-descendants of 
the same species may be not at all changed, some a 
little, and some greatly changed. 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 ad- 
vanced 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, convinced 
by general reasons, believe in the general principle 
of evolution. Breaks incessantly 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 
Lemuridas — between the elephant and in a more 
striking manner between the Ornithorhynchus or 



Chap. VI. AFFINITIES AND GENEALOGY. 201 

Echidna, and other mammals. But all 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 civilised races 
of man will almost certainly exterminate and replace 
throughout the world the savage races. At the 
same time the anthropomorphous apes, as Professor 
Schaaffhausen has remarked, 16 will no doubt be exter- 
minated. The break will then be rendered wider, for 
it will intervene between man in a more civilised state, 
as we may hope, than the Caucasian, and some ape as 
low as a baboon, instead of as at present between the 
negro or Australian and the gorilla. 

With respect to the absence of fossil remains, serving to 
connect man with his ape-like progenitors, no one will 
lay much stress on this fact, who will read Sir C. Lyell's 
discussion, 17 in which he shews that in all the vertebrate 
classes the discovery of fossil remains has been an 
extremely 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 Catarhine 
or Old World division of the Simiadse, after these had 
diverged from the New World division. We will now 
endeavour to follow the more remote traces of his 
genealogy, trusting in the first place to the mutual 
affinities between the various classes and orders, with 
some slight aid from the periods, as far as ascertained, 



16 4 

17 « 



Anthropological Keview,' April, 1867, p. 236. y^C\ C A 

Elements of Geology/ 1865, p. 583-585. 'Antiquity of/MH^y 
1863, p. 115. A^0 00 ° * 

L LIBRA 



202 THE DESCENT OF MAN. Part I. 

of their successive appearance on the earth. The 
LemuridsB stand below and close to the Simiadae, con- 
stituting a very distinct family of the Primates, or, 
according to Hackel, a distinct Order. This group is 
diversified and broken to an extraordinary degree, and 
includes many aberrant forms. It has, therefore, pro- 
bablv suffered much extinction. Most of the remnants 

at 

survive on islands, namely in Madagascar and in the 
islands of the Malayan archipelago, where they have 
not been exposed to such severe competition as they 
would have been on well-stocked continents. This 
group likewise presents many gradations, leading, as 
Huxley remarks, 18 " 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 Lemuriclae ; 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 what it now is. Hence the 
Placentata are generally supposed to have been derived 
from the Implacentata or Marsupials ; not, however, from 
forms closely like 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 Orni- 
thorhynchus an r l Echidna ; and these two forms may 



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



Chap. VI. AFFINITIES AND GENEALOGY. 203 

be safely considered as relics of a much larger group 
which have been preserved in Australia through some 
favourable concurrence of circumstances. The 3Iono- 
tremata are eminently interesting, as in several 
important points of structure they lead towards the 
class of reptiles. 

In attempting to trace the genealogy of the Mam- 
malia, and therefore of man, lower down in the series, 
we become involved in greater and greater obscurity. 
He who wishes to see what ingenuity and knowledge 
can effect, may consult Prof. Hackel's works. 19 I will 
content myself with a few general remarks. Every 
evolutionist will admit that the five great vertebrate 
classes, namely, mammals, birds, reptiles, amphibians, 
and fishes, are all 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 organised and appeared before the others, we may 
conclude that all the members of the vertebrate king- 
dom are derived from some fish-like animal, less highly 
organised than any as yet found in the lowest known 
formations. The belief that animals so distinct as a 
monkey or elephant and a humming-bird, a snake, frog, 
and 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 closely 
binding together all these forms, now so utterly unlike. 



19 Elaborate tables are given in his ' Generelle Morphologie ' (B. ii. 
s. cliii. and s. 425) ; and with more especial reference to man in his 
' Natiirliche Schopfungsgeschichte,' 1868. Prof. Huxley, in reviewing 
this latter work (' The Academy/ 1869, p. 42) says, that he considers 
the phylum or lines of descent of the Vertebrata to be admirably dis- 
cussed by H'aekel, although he differs on some points. He expresses, 
also, his high estimate of the value of the general tenor and spirit of 
the whole work. 



204 THE DESCENT OF MAN. Part I. 

Nevertheless it is certain that groups of animals have 
existed, or do now exist, which serve to connect more or 
less closely the several great vertebrate classes. We 
have seen that the Ornithorhynchus graduates towards 
reptiles; and Prof. Huxley has made the remarkable 
discovery, confirmed by Mr. Cope and others, that the 
old Dinosaurians are intermediate in many important 
respects between certain reptiles and certain birds — the 
latter consisting of the ostrich-tribe (itself evidently a 
widely-diffused remnant of a larger group) and of the 
Archeopteryx, that strange Secondary bird having a 
long tail like that of the lizard. Again, according to 
Prof. Owen, 20 the Ichthyosaurians — great sea-lizards fur- 
nished with paddles — present many affinities with fishes, 
or rather, according to Huxley, with amphibians. This 
latter class (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 highly 
generalised type, that is they presented diversified affi- 
nities with other groups of organisms. The amphibians 
and fishes are also so closely united by the Lepidosiren, 
that naturalists long disputed in which of these two 
classes it ought to be placed. The Lepidosiren and 
some few Ganoid fishes have been preserved from utter 
extinction by inhabiting our rivers, which are harbours 
of refuge, bearing the same relation to the great waters 
of the ocean that islands bear to continents. 

Lastly, one single member of the immense and diver- 
sified class of fishes, namely the lancelet or amphioxus, 
is so different from all other fishes, that Hackel main- 
tains that it ought to form a distinct class in the 
vertebrate kingdom. This fish is remarkable for its 



20 ' ralceontoiu-v,' 1860, p. 199. 



Chap. VI. AFFINITIES AND GENEALOGY. 205 

negative characters ; it can hardly be said to possess a 
brain, vertebral column, or heart, &c. ; so that it was 
classed by 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 crea- 
tures permanently attached to a support. They hardly 
appear like animals, and consist of a simple, tough, 
leathery sack, with two small projecting orifices. They 
belong to the Molluscoida of Huxley — a lower division 
of the great kingdom of the Mollusca ; but they have 
recently been placed by some naturalists amongst the 
Vermes or worms. Their larvae somewhat resemble 
tadpoles in shape, 21 and have the power of swimming 
freely about. Some observations lately made by M. 
Kowalevsky, 22 since confirmed by Prof. Kuppfer, will 
form a discovery of extraordinary interest, if still further 
extended, as I hear from M. Kowalevsky in Naples he 
has now effected. The discovery is 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 dor salts of vertebrate animals. It thus appears, 
if we may rely on embryology, which has always proved 
the safest guide in classification, that we have at last 
gained a clue to the source whence the Vertebrata have 



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

22 ' Memoires de l'Acad. des Sciences de St. Petersbourg,' torn. x. 
No. 15, 18G6. 



206 THE DESCENT OF MAN. Part I. 

been derived. We should thus be justified iu believing 
that at an extremely 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. 

We have thus far endeavoured 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 during 
successive periods, but not in due order of time, the 
structure of our early progenitors. This can be effected 
by means of the rudiments which man still retains, by 
the characters which occasionally make their appear- 
ance 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 
were no doubt once covered with hair, both sexes 
having beards ; their ears were pointed and capable of 
movement ; and their bodies were provided 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 Quadrumana. The great artery and nerve of 
the humerus ran through a supra-condyloid foramen. 
At this or some earlier period, the intestine gave forth 
a much larger diverticulum or caecum than that now 
existing. The foot, judging from the condition of the 
great toe in the foetus, was then prehensile; and our 
progenitors, no doubt, were arboreal m their habits, 
frequenting some warm, forest-clad land. The males 



Chap. VI. AFFINITIES AND GENEALOGY. 207 

were provided with 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. At about this 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 predecessors of man, thus seen in the dim 
recesses of time, must have been as lowly organised 
as the lancelet or amphioxus, or even still more lowly 
organised. 

There is one other point deserving a fuller notice. 
It has long been known that in the vertebrate king- 
dom one sex bears rudiments of various accessory 
parts, appertaining to the reproductive 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 extremely remote progenitor of the whole verte- 
brate kingdom appears to have been hermaphrodite or 
androgynous. 23 But here we encounter a singular 



23 This is the conclusion of one of the highest authorities in com- 
parative anatomy, namely, Prof. Gegenbaur : ' Grundziige 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 Waldeyer 
(as quoted in Humphry's 'Journal of Anat. and Phys.' 1869, p. 161), 
that the sexual organs of even " the higher vertebrata are, in their early 
" condition, hermaphrodite." Similar views have long been held by 
some authors, though until recently not well based. 



208 THE DESCENT OF MAN. Part I. 

difficulty. In the mammalian class the males possess 
in their vesiculaa prostraticae rudiments of a uterus with 
the adjacent passage ; they bear also rudiments of 
mammae, and some male marsupials have rudiments 
of a marsupial sack. 24 Other analogous facts could be 
added. Are we, then, to suppose that some extremely 
ancient mammal possessed organs proper to both sexes, 
that is, continued androgynous after it had acquired 
the chief distinctions of its proper class, and therefore 
after it had diverged from the lower classes of the 
vertebrate kingdom ? This seems improbable in the 
highest degree; for had this been the case, we might 
have expected that some few members of the two 
lower classes, namely fishes 25 and amphibians, would 
still have remained androgynous. We must, on the 
contrary, believe that when the five vertebrate classes 
diverged from their common progenitor the sexes 
had already become separated. To account, however, 
for male mammals possessing rudiments of the acces- 
sory female organs, and for female mammals possessing 
rudiments of the masculine organs, we need not suppose 
that their early progenitors were still androgynous after 
they had assumed their chief mammalian characters. 
It is quite possible that as the one sex gradually 
acquired the accessory organs proper to it, some of the 
successive steps or modifications were transmitted to 
the opposite sex. When we treat of sexual selection, 
we shall meet w r ith innumerable instances of this form 
of transmission, — as in the case of the spurs, plumes, 



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

25 Serranus is well known often to be in an hermaphrodite condition ; 
but Dr. Giinther informs me that he is convinced that this is not its 
normal state. Descent from an ancient androgynous prototype would, 
however, naturally favour end explain, to a certain extent, the recur- 
rence of this condition in these fishes. 



Chap. VI. AFFINITIES AND GENEALOGY. 209 

and brilliant colours, acquired by male birds for battle 
or ornament, and transferred to the females in an im- 
perfect or rudimentary condition. 

The possession by male mammals of functionally 
imperfect mammary organs is, in some respects, espe- 
cially 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 mam- 
malian series, it is probable that the progenitors of the 
class possessed, in like manner, the 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 of 
Kolliker and Lauger, that in the embryo the mammary 
glands can be distinctly traced before the nipples are 
in the least visible ; and it should be borne in mind that 
the development of successive parts in the individual 
generally seems to represent and accord with the deve- 
lopment of successive beings in the same line of descent. 
The Marsupials differ from the Monotremata by possess- 
ing nipples ; so that these organs were probably 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 after the Marsupials had approxi- 
mately acquired their present structure, and therefore 
at a rather late period in the development of the 
mammalian series, any of its members still remained 
androgynous. We seem, therefore, compelled to recur 
to the foregoing view, and to conclude, that the nipples 
were first developed in the females of some very early 
marsupial form, and were then, in accordance with a 
common law of inheritance, transferred in a functionally 
imperfect condition to the males. 

Nevertheless a suspicion has sometimes crossed my 
vol. i. p 



210 THE DESCENT OF MAN. Part I. 

mind that long after the progenitors of the whole 
mammalian class had ceased to be androgynous, both 
sexes might have yielded milk and thus nourished 
their young; and in the case of the Marsupials, that 
both sexes might have carried their young in mar- 
supial sacks. This will not appear utterly incredible, if 
we reflect that the males of svno-nathous fishes receive 
the eggs of the females in their abdominal pouches, 
hatch them, and afterwards, as some believe, nourish 
the young; 26 — 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, keep- 
ing them there until the tadpoles are born ; — that cer- 
tain 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 suspicion first occurred to me from the mammary 
glands in male mammals being developed so much more 
perfectly than the rudiments of those other accessory 
reproductive parts, which are found in the one sex 
though proper to the other. The mammary glands 
and nipples, as they exist in male mammals, can indeed 
hardly be called rudimentary ; they are simply not 
fully developed and not functionally active. They are 
sympathetically affected under the influence of certain 
diseases, like the same organs in the female. At birth 
they often secrete a few drops of milk ; and they have 



26 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. Giinther has likewise 
described similar cases. 



Chap. VI. AFFINITIES AND GENEALOGY. 211 

been known occasionally in man and other mammals to 
become well developed, and to yield a fair supply of 
milk. Now if we suppose that during a former pro- 
longed period male mammals aided the females in 
nursing their offspring, and that afterwards from some 
cause, as from a smaller number of young being pro- 
duced, the males ceased giving this aid, disuse of the 
organs during maturity would lead to their becoming 
inactive ; and from two well-known principles of in- 
heritance this state of inactivity would probably be 
transmitted to the males at the corresponding age of 
maturity. But at all earlier ages these organs would 
be left unaffected, so that they would be equally well 
developed in the young of both sexes. 

Conclusion. — The best definition of advancement or 
progress in the organic scale ever given, is that by 
Von Baer; and this rests on the amount of differ- 
entiation and specialisation of the several parts of 
the same being, when arrived, as I should be inclined 
to add, at maturity. Now as organisms have become 
slowly adapted by means of natural selection for 
diversified lines of life, their parts w r ill have become, 
from the advantage gained by the division of physio- 
logical labour, more and more differentiated and spe- 
cialised for various functions. 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 will still retain 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 
organisation on the whole has advanced throughout the 
world by slow and interrupted steps. In the great 

p 2 



212 THE DESCENT OF MAN. Part I. 

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 inhabiting 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 populations. 
But we must not fall into the error of looking at the 
existing members of any lowly-organised group as per- 
fect representatives 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, 27 
resembling the larvae of existing Ascidians. These 
animals probably gave rise to a group of fishes, as lowly 
organised 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 



27 All vital functions tend to run their course in fixed and recurrent 
periods, and with tidal animals the periods would probably be lunar ; 
for such animals must have been left dry or covered deep with water, — 
supplied with copious food or stinted, — during endless generations, at 
regular lunar intervals. If then the Vertebrata are descended from an 
animal allied to the existing tidal Ascidians, the mysterious fact, that 
with the higher and now terrestrial Vertebrata, not to mention other 
classes, many normal and abnormal vital processes run their course 
according to lunar periods, is rendered intelligible. A recurrent period, 
if approximately of the right duration, when once gained, would not, as 
far as we can judge, be liable to be changed ; consequently it might 
be thus transmitted during almost any number of generations. This 
conclusion, if it could be proved sound, would be curious ; for we should 
then see that the period of gestation in each mammal, and the hatching 
of each bird's eggs, and many other vital processes, still betrayed the 
primordial birthplace of these animals. 



Chap. VI. AFFINITIES AND GENEALOGY. 213 

carry us on to the amphibians. We have seen that 
birds and reptiles were once intimately connected 
together ; and the Monotremata now, in a slight degree, 
connect mammals with reptiles. But no one can at 
present say by what line of descent the three higher 
and related classes, namely, mammals, birds, and rep- 
tiles, were derived from either of the two lower verte- 
brate classes, namely amphibians and fishes. In the 
class of mammals the steps are not difficult to con- 
ceive which led from the ancient Monotremata to 
tne ancient Marsupials ; and from these to the early 
progenitors of the placental mammals. We may thus 
ascend to the Lemuridse ; and the interval is not wide 
from these to the Simiadse. The Simiadae 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, but not, it may be said, of noble quality. The 
world, it has often 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 re- 
cognise 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 unbiassed mind can study any living creature, 
however humble, without being struck with enthusiasm 
at its marvellous structure and properties. 



214 THE DESCENT OF MAN, Part I. 



CHAPTEK VII. 



On the Races of Man. 

The nature and value of specific characters — Application to the races 
of man — Arguments in favour of, and opposed to, ranking the 
so-called races of man as distinct species — Sub-species — Mono- 
genists 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 ex- 
tinction of races — The formation of races — The effects of cross- 
ing — Slight influence of the direct action of the conditions of life 
Slight or no influence of natural selection— Sexual selection. 



*n 



*& 



It is not my intention here to describe the several 
so-called races of men; but to inquire what is the 
value of the differences between them under a classi- 
ficatory point of view, and how they have originated. 
In determining whether two or more allied forms 
ought to be ranked as species or varieties, natu- 
ralists are practically guided by the following con- 
siderations ; namely, the amount of difference between 
them, and whether such differences relate to few or 
many points of structure, and whether they are of 
physiological importance ; but more especially whether 
they are constant. Constancy of character is what is 
chiefly valued and sought for by naturalists. Whenever 
it can be shewn, or rendered probable, that the forms 
in question have remained distinct for a long period, 
this becomes an argument of much weight in favour 
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 



Chap. VII. THE RACES OF MAN. 215 

test of tlieir specific distinctness ; and their continued 
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 repugnance to mutual pairing. 

Independently of blending from intercrossing, the 
complete absence, 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 somewhat 
different consideration from mere constancy of character, 
for two forms may be highly variable and yet not 
yield intermediate varieties. Geographical distribution 
is often unconsciously and sometimes consciously brought 
into play ; so that forms living in two widely separated 
areas, in which most of the other inhabitants are speci- 
fically distinct, are themselves usually looked at as dis- 
tinct ; but in truth this affords no aid in distinguishing 
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 our nice powers of discrimination 
gained by the long habit of observing ourselves. In 
India, as Elphinstone remarks, 1 although a newly-arrived 
European 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 European nations. Even the most 
distinct races of man, with the exception of certain 
negro tribes, are much more like each other in form 



1 ' History of India,' 1841, vol. i. p. 323. Father Ripa makes exactly 
tiie tame remark with respect to the Chinese. 



216 THE DESCENT OF MAN. Part I. 

than would at first be supposed. This is well shewn by 
the French photographs in the Collection Anthropolo- 
gique du Museum of the men belonging to various 
races, the greater number of which, as many persons 
to whom I have shown them have remarked, mioht 
pass for Europeans. Nevertheless, these men if seen 
alive would undoubtedly appear very distinct, so that 
we are clearly much influenced in our judgment by 
the mere colour of the skin and hair, by slight differ- 
ences in the features, and by expression. 

There is, however, no doubt that the various races, 
when carefully compared and measured, differ much 
from each other, — as in the texture of the hair, the 
relative proportions of all parts of the body, 2 the capa- 
city of the lungs, the form and capacity of the skull, 
and even in the convolutions of the brain. 3 But it 
would be an endless task to specify the numerous points 
of structural difference. The races differ also in con- 
stitution, in acclimatisation, and in liability to certain 
diseases. Their mental characteristics 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, 4 who live 



2 A vast number of measurements of Whites, Blacks, and Indians, are 
given in the ' Investigations in the Military and Anthropolog. Statistics 
of American Soldiers,' by B. A. Gould, 1869, p. 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 'Beise der Novara: Anthropolog. Theil,' 1867. 

* See, for instance, Mr. Marshall's account of the brain of a Bush- 
woman, in ' Bhil. Transact.' 1861, p. 519. 

4 Wallace, ' The Malay Archipelago,' vol. ii. 1869, p. 178. 



Chap. VII. THE EACES OF MAN. 217 

under the same physical conditions, and are separated 
from each other only by a narrow space of sea. 

We -will first consider the arguments wdiich may be 
advanced in favour of classing the races of man as 
distinct species, and then those on the other side. If a 
naturalist, who had never before seen such beings, were 
to compare a Negro, Hottentot, Australian, or Mongolian, 
he would at once perceive that they differed in a multi- 
tude of characters, some of slight and some of consider- 
able 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 disposition. 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 affixing 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 centuries ; and that negroes, apparently identical 
with existing negroes, had lived at least 4000 years 
ago. 5 He would also hear from an excellent observer, 



5 With respect to the figures in the famous Egyptian caves of Abou- 
Simbel, M. Pouchet says (' The Plurality of the Human Kaces,' Eng. 
translat. 1861, p. 50), that he was far from finding recognisable repre- 
sentations of the dozen or more nations which some authors believe 
that they can recognise. Even some of the most strongly-marked 
races cannot be identified witli 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; where- 
as Knox, another firm believer in the specific distinction of the races 
of man ('Races of Man,' 1850, p. 201), speaking of young Memnon 
(the same person with Rameses II., as I am infurmedby Mr. Birch) in- 
sists in the strongest manner that he is identical in character with the 
Jews of Antwerp. Again, whilst looking in the British Museum with 
two competent judges, officers of the establishment, at the statue of 
Amunoph III., we agreed that he had a strongly negro cast of features ; 



218 THE DESCENT OF MAN. Pabt I. 

Dr. Lund, 6 that the human skulls found in the caves of 
Brazil, entombed with many extinct mammals, belonged 
to the same type as that now prevailing throughout the 
American Continent. 

Our naturalist would then perhaps turn to geogra- 
phical distribution, and he would probably declare that 
forms differing not only in appearance, but fitted for 
the hottest and dampest or driest countries, as well as 
for the arctic regions, must be distinct species. He 
might appeal to the fact that no one species in the 
group next to man, namely the Quaclrumana, can resist 
a low temperature or any considerable change of climate ; 
and that those 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, 7 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 mani- 
festly 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 shewn, 
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 opposed to the above rule, for most of 
the productions of the Southern and Northern halves 
differ widely ; yet some few living forms, as the 



but Messrs. Nott and Gliddon (ibid. p. 146, fig. 53) describe him as 
" a hybrid, but not of negro intermixture." 

6 As quoted by Nott and Gliddon, « Types of Mankind,' 1854, p. 439. 
They give also corroborative evidence ; but C. Vogt thinks that the 
subject requires further investigation. 

7 " Diversity of Origin of the Human Kaces," in the ' Christian 
Examiner,' July, 1850. 



Chap. VII. THE EACES OF MAN. 219 

opossum, range from the one into the other, as did 
formerly some of the gigantic Edentata. The Esqui- 
maux, like other Arctic animals, extend round the 
whole polar regions. It should be observed that the 
mammalian forms which inhabit the several zoological 
provinces, do not differ from each other in the same 
degree; 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 same continents from those 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 varieties of the same 
kind of domestic animal should be ranked as specifically 
distinct, that is, whether any of them are descended from 
distinct wild species, every naturalist would lay much 
stress on the fact, if established, of their external parasites 
being specifically distinct. All the more 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 infested 
by the same species of Pediculi or lice. Now Mr. A. 
Murray has carefully examined the Pediculi collected in 
different countries from the different races of man ; 8 
and he finds that they differ, not only in colour, but 
in the structure of their claws and limbs. In every 
case in which numerous specimens were obtained the 
differences were constant. The surgeon of a whaling 
ship in the Pacific assured me that^ when 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 clays. These Pediculi 



8 'Transact. E. Soc. of Edinburgh,' vol. xxii. 1861. p. 567. 



220 THE DESCENT OF MAN. Part I. 

were darker coloured 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 
procured four kinds from Africa, namely from the 
Negroes of the Eastern and Western coasts, from the 
Hottentots and Caffres ; two kinds from the natives 
of Australia ; two from North, and two from South 
America. In these latter cases it may be presumed 
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 investigation, would next inquire whether the 
races of men, when crossed, were in any degree sterile. 
He might consult the work 9 of a cautious and philo- 
sophical observer, Professor Broca ; 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 Australia and Tasmania rarely produce 
children to European men ; the evidence, however, on 
this head has now been shewn 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. 10 Again, it has often 



9 'On the Phenomena of Hybridity in the Genus Homo,' Eng. 
translat. 1864. 

10 See the interesting letter by Mr. T. A. Murray, in the ' Anthro- 
polog. Keview,' April, 1868, p. liii. In this letter Count Strzeleeki's 



Chap. VII. THE KACES OF MAN. 221 

been said that when mulattoes intermarry they produce 
few children ; on the other hand, Dr. Bachman of 
Charlestown u positively asserts that he has known 
mulatto families which have intermarried for several 
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 conclusion. 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 de- 
graded and anomalous position of the class, and by the 
profligacy of the women. A certain amount of absorp- 
tion of mulattoes into negroes must always be in pro- 
gress ; and this would lead to an apparent diminution 
of the former. The inferior vitality of mulattoes is 
spoken of in a trustworthy work 12 as a well-known 
phenomenon ; but this is a different consideration from 
their lessened fertility ; and can hardly 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 mulattoes cannot 
be put under the category of extremely distinct species. 
The common Mule, so notorious for long life and vigour, 
and yet so sterile, shews how little necessary connection 



statement, that Australian women who have borne children to a white 
man are afterwards sterile with their own race^ is disproved. M. A. de 
Quatrefages has also collected (' Eevue des Cours Scientifiques,' March, 
1869, p. 239) much evidence that Australians and Europeans are not 
sterile when crossed. 

11 ' An Examination of Prof. Agassiz's Sketch of the Nat. Provinces 
of the Animal World,' Charleston, 1855, p. 44. 

12 'Military and Anthropolog. Statistics of American Soldiers,' by 
B. A. Gould, 18G9, p. 319. 



222 THE DESCENT OF MAN. Part I. 

there is in hybrids between lessened fertility and vitality : 
other analogous cases could be added. 

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 distinctness. 
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 reciprocal 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 quite fertile. The degrees 
of sterility do not coincide strictly with the degrees of 
difference in external structure or habits of life. Man 
in many respects may be compared with those animals 
which have long been domesticated, and a large body 
of evidence can be advanced in favour of the Pallasian 
doctrine 13 that domestication tends to eliminate the 



13 ' 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 together, is incidental on other 
acquired differences. The nature of these differences is unknown, but 
they relate more especially to the reproductive system, and much less 
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 repro- 
ductive system, and we have good reason to believe (as before re- 
marked) that the fluctuating conditions of domestication tend to elimi- 
nate that sterility which is so general with species in a natural state 
when crossed. It has elsewhere been shewn by me (ibid. vol. ii. p. 185, 
and' ' Origin of Species,' oth 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 



Chap. VII. THE EACES OF MAN. 223 

sterility which is so general a result of the crossing of 
species in a state of nature. From these several con- 
siderations, it may be justly urged that the perfect ferti- 
lity of the intercrossed races of man, if established, 
would not absolutely preclude us from ranking them as 
distinct species. 

Independently of fertility, the character of the off- 
spring from a cross has sometimes been thought to 
afford evidence whether the parent-forms ought to be 
ranked as species or varieties ; but after carefully study- 
ing the evidence, I have come to the conclusion that no 
general rules of this kind can be trusted. Thus with 
mankind the offspring of distinct races resemble in all 
respects the offspring of true species and of varieties. 
This is shewn, for instance, by the manner in which 
the characters of both parents are blended, and by 
one form absorbing another through repeated crosses. 
In this latter case the progeny both of crossed species 
and varieties retain for a long period a tendency to 
revert to their ancestors, especially to that one which 
is prepotent in transmission. When any character has 
suddenly appeared in a race or species as the result of a 



possible that their sterility should he augmented by the preservation or 
survival of the more and more sterile individuals ; for as the sterility 
increases fewer and fewer offspring will be produced i'rom 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 
numerous species, a series can be formed 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, for 
the germen swells. It is here manifestly impossible to select the more 
sterile individuals, which have already ceased to yield seeds ; so tW_ . ^ 
the acme of sterility, wheu the germen alone is affected, caunpif*ne\ P A > 
gained through selection. This acme, and no doubt the olhei^i\&es 
of sterility, are the incidental results of certain unknowm d^^iicO*^' ' ^< 
in the constitution of the reproductive system of the species/ "wiucKarj^^.,-^ 
crossed. / ^0 

Lr LIBRAE 



224 THE DESCENT OF MAN. Part I. 

single act of variation, as is general with monstrosities, 14 
and this race is crossed with another not thus charac- 
terised, the characters in question do not commonly 
appear in a blended condition in the young, but are 
transmitted to them either perfectly developed or not at 
all. As with the crossed races of man cases of this kind 
rarely or never occur, this may be used as an argument 
against the view suggested by some ethnologists, namely 
that certain characters, for instance the blackness of the 
negro, first appeared as a sudden variation or sport. 
Had this occurred, it is probable that mulattoes would 
often have been born, either completely black or com- 
pletely white. 

We have now seen that a naturalist might feel him- 
self fully justified in ranking the races of man as distinct 
species ; for he has found that they are distinguished by 
many differences iu structure and constitution, some 
being of importance. These differences have, also, re- 
mained nearly constant for very long periods of time. 
He 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, in accordance 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 enquire whether the forms of man 
kept distinct like ordinary species, when mingled to- 



14 ' The Variation of Animals,' &c, vol. ii. p. 92. 



Chap. VII. THE EACES OF MAN. 225 

gether in large numbers in the same country, lie would 
immediately discover that this was by no means the 
case. In Brazil he would behold an immense mongrel 
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. 15 In many parts of the 
same continent he would meet with the most complex 
crosses between Negroes, Indians, and Europeans ; and 
such triple crosses afford the severest test, judging from 
the vegetable kingdom, 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 Viti Archipelago a popula- 
tion of Polynesians and Negritos crossed in all degrees. 
Many analogous cases could be added, for instance, in 
South Africa. Hence the races of man are not suffi- 
ciently distinct to co-exist without fusion ; and this it 
is, which in all ordinary cases affords the usual test of 
specific distinctness. 

Our naturalist would likewise be much disturbed as 
soon as he perceived that the distinctive characters of 
every race of man were highly variable. This strikes 
every one when he first beholds the negro-slaves in 
Brazil, who have been imported from all parts of Africa. 
The same remark holds good with the Polynesians, 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 often been said. Hottentot women offer certain 



15 M. de Quatrefages has given (' Anthropolog. Eeview,' Jan. 1860, 
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. 

VOL. I. Q 



226 THE DESCENT OF MAN. Part I. 

peculiarities, more strongly marked than those occur- 
ring in any other race, but these are known not to 
be of constant occurrence. In the several American 
tribes, colour and hairyness differ considerably ; as does 
colour 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 ; 16 and so it is with 
every other character. Now all naturalists 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 
organic being, 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 (Buffon), seven (Hunter), eight (Agassiz), eleven 
(Pickering), fifteen (Bory St. Vincent), sixteen (Des- 
moulins), twenty- two (Morton), sixty (Crawfurd), or as 
sixty-three, according to Burke. 17 This diversity of 
judgment does not prove that the races ought not to be 
ranked as species, but it shews 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 under- 



16 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. 

17 See a good discussion on this subject in Waitz, ' Introduct. to 
Anthropology,' Eng. translat. 1863, p. 198-208, 227. I have taken 
some of the above statements from H. Tuttle's ' Origin and Antiquity 
of Physical Man,' Boston, 1866, p. 35. 



Chap. VII. THE RACES OF MAN. 227 

take the description of a group of highly varying 
organisms, has encountered cases (I speak after ex- 
perience) precisely like that of man ; and if of a cautious 
disposition, he will end by uniting all the forms which 
graduate into each other as 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 Cerco- 
pithecus, 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 ap- 
pear to be specifically distinct, were found to graduate 
into each other by close steps, they would be ranked by 
most naturalists as mere varieties or races ; and thus the 
greater number of naturalists have acted with respect 
to the races of man. Nevertheless it must be confessed 
that there are forms, at least in the vegetable king- 
dom, 18 which we cannot avoid naming as species, but 
which are connected together, independently of inter- 
crossing, by numberless gradations. 

Some naturalists have lately employed the term 
" sub-species " to designate forms which possess many of 
the characteristics of true species, but which hardly de- 
serve so high a rank. Now if we reflect on the weighty 
arguments, above given, for raising the races of man to 
the dignity of species, and the insuperable difficulties 
on the other side in defining them, the term " sub- 



18 Prof. N'ageli has carefully described several striking cases in his 
' Botanische Mittheilungen,' B. ii. 1866, s. 294-369. Prof. Asa Gray 
has made analogous remarks on some intermediate forms in the Com- 
posite of N. America. 

Q 2 



228 THE DESCENT OF MAN. Part I. 

species " might here be used with much propriety. But 
from long habit the term " race " will perhaps always 
be employed. The choice of terms is only so far im- 
portant as it is highly desirable to use, as far as that 
may be possible, the same terms for the same degrees of 
difference. Unfortunately this is rarely possible ; for 
within the same family the larger genera generally 
include closely-allied forms, which can be distinguished 
only with much difficulty, whilst the smaller genera 
include forms that are perfectly distinct ; yet all must 
equally be ranked as species. So again the species 
within the same large genus by no means resemble 
each other to the same degree : on the contrary, in 
most cases some of them can be arranged in little groups 
round other species, like satellites round planets. 19 

The question whether mankind consists of one or 
several species has of late years been much agitated by 
anthropologists, who are divided into two schools of 
monogenists and polygenists. Those who do not admit 
the principle of evolution, must look at species either 
as separate creations or as in some manner distinct 
entities ; and they must decide what forms to rank as 
species by the analogy of other organic beings which 
are commonly thus received. But it is a hopeless en- 
deavour to decide this point on sound grounds, until 
some definition of the term " species " is generally ac- 
cepted ; and the definition must not include an element 
which cannot possibly be ascertained, such as an act of 
creation. We might as well attempt without any defi- 
nition to decide whether a certain number of houses 
should be called a village, or town, or city. We have a 
practical illustration of the difficulty in the never- 



19 



' Origin of Species,' 5th edit. p. 68. 



Chap. VII. THE RACES OF MAN. 229 

ending donbts whether many closely-allied mammals, 
birds, insects, and plants, which represent each other in 
North America and Europe, should be ranked species 
or geographical races ; and so it is with the productions 
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 
greater number of rising men, will feel no doubt that 
all the races of man are descended from a single primi- 
tive stock ; whether or not they think fit to designate 
them as distinct species, for the sake of expressing their 
amount of difference. 20 With our domestic animals the 
question whether the various races have arisen from 
one or more species is different. Although all such 
races, as well as all the natural species within the same 
genus, have undoubtedly sprung from the same primi- 
tive stock, yet it is a fit subject for discussion, whether, 
for instance, all the domestic races of the dog have 
acquired their present differences since some one species 
was first domesticated and bred by man ; or whether they 
owe some of their characters to inheritance from distinct 
species, which had already been modified in a state of 
nature. With mankind no such question can arise, for 
he cannot be said to have been domesticated at any 
particular period. 

When the races of man diverged at an extremely 
remote epoch from their common progenitor, they will 
have differed but little from each other, and been few 
in number ; consequently they will then, as far as their 
distinguishing characters are concerned, have had less 
claim to rank as distinct species, than the existing so- 



20 See Prof. Huxley to this effect in the ' Fortnightly Review,' 1865, 
p. 275. 



230 THE DESCENT OF MAN. Part I. 

called races. Nevertheless such early races would per- 
haps have been ranked by some naturalists as distinct 
species, so arbitrary is the term, if their differences, 
although extremely slight, had been more constant than 
at present, and had not graduated into each other. 

It is, however, possible, though far from probable, 
that the early progenitors of man might at first have 
diverged much in character, until they became more 
unlike each other than are any existing races ; but that 
subsequently, as suggested by Vogt, 21 they converged 
in character. When man selects for the same object 
the offspring of two distinct species, he sometimes 
induces, as far as general appearance is concerned, 
a considerable amount of convergence. This is the 
case, as shewn by Von Nathusius, 22 with the improved 
breeds of pigs, which are descended from two distinct 
species ; and in a less well-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 characters, 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 
applied to superficial and adaptive resemblances. It 



21 ' Lectures on Man,' Eng, translat. 1864, p. 468. 

22 'Die Kacen des Schweines,' 1860, s. 46. 'Vorstudien fur Ge- 
schichte, &c, Schwemeschadel/ 1864, s. 104. With respect to cattle, 
tee M. de Quatrefages, ' Unite' de l'Espece Humaine,' 1861, p. 119. 



Chap. VII. THE KACES OF MAN. 231 

would be extremely rash in most cases to attribute to 
convergence close similarity in many points of struc- 
ture in beings which had once been widely different. 
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 infinitude of complex 
relations, namely on the variations which have arisen, 
these being due to causes far too intricate to be followed 
out, — on the nature of the variations which have been 
preserved, and this depends on the surrounding physical 
conditions, and in a still higher degree on the sur- 
rounding organisms with which each has come into 
competition, — and lastly, on inheritance (in itself a 
fluctuating element) from innumerable progenitors, all 
of which have had their forms determined through 
equally complex relations. It appears utterly incredible 
that two organisms, if differing in a marked manner, 
should ever afterwards converge so closely as to lead 
to a near approach to identity throughout their whole 
organisation. In the case of the convergent races of pigs 
above referred to, evidence of their descent from two pri- 
mitive stocks is still plainly retained, according to Von 
Nathusius, in certain bones of their skulls. If the races 
of man were descended, as supposed by some naturalists, 
from two or more distinct species, which had differed as 
much, or nearly as much, from each other, as the orang 
differs from the gorilla, it can hardly be doubted that 
marked differences in the structure of certain bones would 
still have been discoverable in man as he now exists. 

Although the existing races of man differ in many 
respects, as in colour, hair, shape of skull, proportions 
of the body, &c, yet if their whole organisation be taken 



232 THE DESCENT OF MAN. Part I. 

into consideration they are found to resemble each 
other closely in a multitude of points. Many of these 
points are of so unimportant or of so singular a nature, 
that it is extremely improbable that they should have 
been independently 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 differ as much 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, 
shewing 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 carefully read Mr. Tylor's and Sir 
J. Lubbock's interesting works 23 can hardly fail to be 
deeply impressed with the close similarity between 
the men of all races in tastes, dispositions and habits. 
This is shewn by the pleasure which they all take in 
dancing, rude music, acting, painting, tattooing, and 
otherwise decorating themselves, — in their mutual 
comprehension of gesture-language — and, as I shall be 
able to shew in a future essay, by the same expression 
in their features, and by the same inarticulate cries, 
when they are excited by various emotions. This 
similarity, or rather identity, is striking, when contrasted 
with the different expressions which may be observed 
in distinct species of monkeys. There is good evi- 
dence that the art of shooting with bows and arrows has 
not been handed down from any common progenitor of 



23 Tylor's « Early History of Mankind,' 1865 ; for the evidence with 
respect to gesture-language, see p. 54. Lubbock's • Prehistoric Times,' 
2nd edit. 1869. 



Chap. VII. THE KACES OF MAN. 233 

mankind, yet the stone arrow-heads, brought from the 
most distant parts of the world and manufactured at the 
most remote periods, are, as Mlsson has shewn, 24 almost 
identical ; and this fact can only be accounted for by 
the various races having similar inventive or mental 
powers. The same observation has been made by 
archaeologists 25 with respect to certain widely-prevalent 
ornaments, such as zigzags, &c; and with respect to 
various simple beliefs and customs, such as the burying 
of the dead under megalithic structures. I remember 
observing in South America, 26 that there, as in so many 
other parts of the world, man has generally chosen the 
summits of lofty hills, on which to throw up piles of 
stones, either for the sake of recording some remarkable 
event, or for burying his 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 all 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 unim- 
portant points of resemblance between the several races 
of man in bodily structure 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 were thus characterised. We 
thus gain some insight into the early state of man, 



34 ' The Primitive Inhabitants of Scandinavia/ Eng. translaj^mAJQ A j 
by Sir J. Lubbock, 1868, p. 104. /V ~* , 

25 Hodder M. Westropp, on Cromlechs, &c, ' JournajAf^Et]jliP- S **<v 
logical Soc' as given in 'Scientific Opinion,' June 2nd, 18^9£p~. 2r ^^.z*** « 



26 ' Journal of Kesearches : Voyage of the " Beagle," ' n.39. n , 

1. 1. LIBRA* 




234 THE DESCENT OF MAN. Part I. 

before he had spread step by step over the face of the 
earth. The spreading of man to regions widely sepa- 
rated by the sea, no doubt, preceded any considerable 
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 practised 
by savages in all parts of the world, specifies those 
which man could not have known, when he first wan- 
dered from his original birth-place ; for if once learnt 
they would never have been forgotten. 27 He thus shews 
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 already been dis- 
covered, 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 re- 
mote epoch, when the land in many places stood at a 
very different level, 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, consider- 
" ing that so many races 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 now pos- 
sessed 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 



' Prehistoric Times,' 1869, p. 574. 



Chap. VII. THE EACES OF MAN. 235 

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. 
Without 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 very few 
arts 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 indifference whether the so-called races of 
man are thus designated, or are ranked as species 
or sub-species; but the latter term appears the most 
appropriate. Finally, we may conclude that when 
the principles of evolution are generally accepted, as 
they 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 from a single 
pair possessing some new character, or even from a 
single individual thus characterised, by carefully match- 



236 THE DESCENT OF MAN. Part I. 

ing the varying offspring ; but most of our races have 
been formed, not intentionally from a selected pair, 
but unconsciously by the preservation of many indi- 
viduals 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 horses, were habitually preferred, we may feel 
sure that two distinct sub-breeds would, in the course 
of time, be produced, without any particular pairs 
or individuals having been separated and bred from 
in either country. Many races have been thus formed, 
and their manner of formation is closely analogous with 
that of natural species. We know, also, that the 
horses which have been brought to the Falkland 
Islands have become, during successive generations, 
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 all the individuals having been 
subjected to the same conditions, aided, perhaps, by 
the principle of reversion. The new sub-breeds in 
none of these cases are 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 Extinction of the Races of Man. — The partial 
and complete extinction of many races and sub-races 
of man are historically known events. Humboldt saw 
in South America a parrot which was the sole living 
creature that could speak the language of a lost tribe. 



Chap. VII. THE KACES OF MAN. 237 

Ancient monuments and stone implements found in 
all parts of the world, of which no tradition is pre- 
served by the present inhabitants, indicate much 
extinction. Some small and broken tribes, remnants 
of former races, still survive in isolated and gene- 
rally mountainous districts. In Europe the ancient 
races were all, according to Schaaffhausen, 28 " 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 29 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 high characteristics, and is "entirely different 
" from any other race, ancient or modern, that we have 
" ever heard of." It differed, therefore, from the qua- 
ternary race of the caverns of Belgium. 

Unfavourable physical conditions appear to have had 
but little effect in the extinction of races. 30 Man has 
long lived in the extreme regions of the North, with 
no wood wherewith to make his canoes or other imple- 
ments, and with blubber alone for burning and giving 
him warmth, but more especially for melting the snow. 
In the Southern extremity of America the Fuegians 
survive without the protection of clothes, or of any 
building worthy to be called a hovel. In South Africa 
the aborigines wander over the most arid plains, where 
dangerous beasts abound. Man can withstand the 
deadly influence of the Terai at the foot of the Hima- 
laya, and the pestilential shores of tropical Africa. 



58 Translation in ' Anthropological Eeview,' Oct. 1S68, p. 431. 

29 ' Transact. Internat. Congress of Prehistoric Arch.' 1868, p. 172- 
175. See also Broca (translation) in ' Anthropological Kcview,' Oct. 
1868, p. 410. 

30 Dr. Gerland ' Ueber das Aussterben der Natnrvolkcr/ 1868, s. 82. 



238 THE DESCENT OF MAN. Part I. 

Extinction follows chiefly from the competition of 
tribe with tribe, and race with race. Various checks 
are always in action, as specified in a former chapter, 
which serve to keep down the numbers of each savage 
tribe, — such as periodical famines, the wandering of 
the parents and the consequent deaths of infants, pro- 
longed suckling, the stealing of women, wars, accidents, 
sickness, licentiousness, especially infanticide, and, 
perhaps, lessened fertility from less nutritious food, and 
many hardships. If from any cause any one of these 
checks is lessened, even in a slight degree, the tribe 
thus favoured will tend to increase ; and when one 
of two adjoining tribes becomes more numerous and 
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 is extinct. 31 

When civilised nations come into contact with bar- 
barians the struggle is short, except where a deadly cli- 
mate gives its aid to the native race. Of the causes which 
lead to the victory of civilised nations, some are plain 
and some very 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 are highly destructive ; and it appears 
that in every nation a new disease causes much death, 
until those who are most susceptible to its destructive 
influence are gradually weeded out ; 32 and so it may be 
with the evil effects from spirituous liquors, as well as 
with the unconquerably strong taste for them shewn by 
so many savages. It further appears, mysterious as is 



31 Gerland (ibid. s. 12) gives facts in support of this statement. 

32 See remarks to this effect in Sir H. Holland's ' Medical Notes and 
Reflections,' 1839, p. 390. 



Chap. VII. THE EACES OF MAN. 239 

the fact, that the first meeting of distinct and separated 
people generates disease. 33 Mr. Sproat, who in Van- 
couver Island closely attended to the subject of extinc- 
tion, believes that changed habits of life, which always 
follow from the advent of Europeans, induces much ill- 
health. He lays, also, great stress on so trifling a cause 
as that the natives become " bewildered and dull by the 
" new life around them ; they lose the motives for exer- 
" tion, and get no new ones in their place." M 

The grade of civilisation seems a most important 
element in the success of nations which come in compe- 
tition. A few centuries ago Europe feared the inroads 
of Eastern barbarians ; now, any such fear would be ridi- 
culous. It is a more curious fact, that savages did not 
formerly waste away, as Mr. Bagehot has remarked, 
before the classical nations, as they now do before 
modern civilised 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 perish- 
ing barbarians. 35 

Although the gradual decrease and final extinction 
of the races of man is an obscure problem, we can see 
that it depends on many causes, differing in different 
places and at different times. It is the same difficult 
problem as that presented by the extinction of one of 
the higher animals — of the fossil horse, for instance, 
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 

33 1 have collected ( ; Journal of Besearches, Voyage of the " Beagle," ' 
p. 435) a good many oases bearing on this subject : see also Gerland, 
ibid. s. 8. Poeppig speaks of the " breath of civilisation as poisonous 
" to savages." 

34 Sproat, ' Scenes and Studies of Savage Life,' 1868, p. 284. 

35 Bagehot, " Physics and Politics," ' Fortnightly Beview,' April 1, 
1868, p. 455. 



240 THE DESCENT OF MAN. Part I. 

conscious of this parallelism, for he compares his future 
fate with that of the native rat almost exterminated by 
the European rat. The difficulty, though great to our 
imagination, and really great if we wish to ascertain 
the precise causes, 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 hindered by 
various checks ; so that if any new check, or cause of 
destruction, even a slight one, be superadded, the race 
will surely decrease in number ; and as it has every- 
where been observed that savages are much opposed to 
any change of habits, by which means injurious checks 
could be counterbalanced, decreasing numbers will 
sooner or later lead to extinction ; the end, in most 
cases, being promptly determined by the inroads of 
increasing and conquering tribes. 

On the Formation of the Baces of Man. — It may be 
premised that when we find the same race, though 
broken up into distinct tribes, ranging over a great 
area, as over America, we may attribute their general 
resemblance to descent from a common stock. In some 
cases the crossing of races already distinct has led to 
the formation of new races. 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 36 through the Aryan branches having been 
largely crossed during their wide diffusion by various 
indigenous tribes. When two races in close contact 



36 " On Anthropology," translation, ' Anthropolog. Eeview,' Jan. 
1868, p. 38. 



Chap. VIL THE RACES OF MAN. 241 

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-coloured 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 Hindoos. 37 Whether a heterogeneous people, such 
as the inhabitants of some of the Polynesian islands, 
formed by the crossing of two distinct races, with few 
or no pure members left, would ever become homo- 
geneous, is not known from direct evidence. But as 
with our domesticated animals, a crossed breed can 
certainly, in the course of a few generations, be fixed 
and made uniform by careful selection, 38 we may infer 
that the free and prolonged intercrossing during many 
generations of a heterogeneous mixture would supply 
the place of selection, and overcome any tendency to 
reversion, so that a crossed race would ultimately be- 
come 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 
colour of the skin is the most conspicuous and one of 
the best marked. Differences of this kind, it was for- 
merly thought, could be accounted for by long expo- 
sure under different climates ; but Pallas first shewed 
that this view is not tenable, and he has been followed 
by almost all anthropologists. 39 The view has been 



37 ' The Annals of Rural Bengal,' 1868, p. 134. 

38 ' The Variation of Animals and Plants under Domestication,' vol. 
ii. p. 95. 

89 Pallas, 'Act. Acad. St. Petersburgh,' 1780, part ii. p. 69. He 
was followed by Rudolphi, in his ' Beytr'age zur Anthropologic, ' 1812. 
An excellent summary of the evidence is given by Godron, ' De 
l'Espece,' 1859, vol. ii. p. 246, &c. 

VOL. I. R 



242 THE DESCENT OF MAN. Paet I. 

rejected chiefly because the distribution of the variously 
coloured races, most of whom must have long inhabited 
their present homes, does not coincide with correspond- 
ing differences of climate. Weight must also be given 
to such cases as that of the Dutch families, who, as 
we hear on excellent authority, 40 have not undergone 
the least change of colour, after residing for three cen- 
turies in South Africa. The uniform appearance in 
various parts of the world of gypsies and Jews, though 
the uniformity of the latter has been somewhat exagge- 
rated, 41 is likewise an argument on the same side. A 
very damp or a very dry atmosphere has been supposed 
to be more influential in modifying the colour of the 
skin than mere heat ; but as D'Orbigny in South 
America, and Livingstone in Africa, arrived at diame- 
trically opposite conclusions with respect to dampness 
and dryness, any conclusion on this head must be con- 
sidered as very doubtful. 42 

Various facts, which I have elsewhere given, prove 
that the colour of the skin and hair is sometimes corre- 
lated in a surprising 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 during a long series of generations from 
the deadly influence of the miasmas of their native 
countries. 

I afterwards found that the same idea had long ago 



40 Sir Andrew Smith, as quoted by Knox, ' Races of Man,' 1850, 
p. 473. 

41 See De Quatrefages on this head, • Revue des Cours Scientifiques,' 
Oct. 17, 1868, p. 731. 

4 " Livingstone's ' Travels and Researches in S. Africa,' 1857, p. 338, 
329. D'Orbigny, as quoted by Godron, • De l'Espece,' vol. ii. p. 266. 



Chap. VII. THE RACES OF MAN. 243 

occurred to Dr. Wells. 43 That negroes, and even mulat- 
toes, are almost completely exempt from the yellow- 
fever, which is so destructive in tropical America, has 
long been known. 44 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 return home invalided. 45 This immu- 
nity in the negro seems to be partly inherent, de- 
pending on some unknown peculiarity of constitution, 
and partly the result of acclimatisation. Pouchet 46 
states that the negro regiments, borrowed from the 
Viceroy of Egypt for the Mexican war, which had been 
recruited near the Soudan, escaped the yellow-fever 
almost equally well with the negroes originally brought 
from various parts of Africa, and accustomed to the 
climate of the West Indies. That acclimatisation plays 
a part is shewn by the many cases in which negroes, 
after having resided for some time in a colder climate, 
have become to a certain extent liable to tropical 
fevers. 47 The nature of the climate under which the 
white races have long resided, likewise has some in- 
fluence on them ; for during the fearful epidemic of 
yellow-fever in Demerara during 1837, Dr. Blair found 
that the death-rate of the immigrants was proportional 



43 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. svi) to my ' Origin of Species/ Various cases of 
colour correlated with constitutional peculiarities are given in my 
' Variation of Animals under Domestication,' vol. ii. p. 227, 335. 

44 See, for instance, Nott and Gliddon, ' Types of Mankind,' p. 68. 

45 Major Tulloch, in a paper read before the Statistical Society, 
April 20th, 1840, and given in the ' Athenaeum,' 1840, p. 353. 

46 * The Plurality of the Human Race ' (translat.), 1864, p. 60. 

4 ' Quatrefages, ' Unite de l'Espece Humaine,' 1861, p. 205. Waitz, 
'Introduct. to Anthropology,' translat. vol. i. 1863, p. 124. Living- 
stone gives analogous cases in his ' Travels.' 

R 2 



244 THE DESCENT OF MAN. Part I. 

to the latitude of the country whence they had come. 
With the negro the immunity, as far as it is the result 
of acclimatisation, 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. 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 colour of his skin is a mere conjec- 
ture : it may be correlated with some difference in his 
blood, nervous system, or other tissues. Nevertheless, 
from the facts above alluded to, and from some connec- 
tion apparently existing between complexion and a 
tendency to consumption, the conjecture seemed to me 
not improbable. Consequently I endeavoured, with but 
little success, 48 to ascertain how far it held good. The 



48 In the spring of 1862 I obtained permission from the Director- 
General of the Medical department of the Army, to transmit to the 
surgeons 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 colour of the dermal appendages 
" and the constitution ; and it being notorious that there is some limited 
" degree of relation between the colour of the races of man and the 
" climate inhabited by them ; the following investigation seems worth 
" consideration. Namely, whether there is any relation in Europeans 
" between the colour of their hair, and their liability to the diseases of 
" tropical countries. If the surgeons of the several regiments, 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-coloured 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 colour of the hair and consti- 
" tutional liability to tropical diseases. Perhaps no such relation would 



Chap. VII. THE RACES OF MAN. 245 

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 with- 
stood the climate in a wonderful manner. When he 
first arrived as a boy on the coast, an old and expe- 
rienced negro chief predicted from his appearance that 
this would prove the case. Dr. Nicholson, of Antigua, 
after having attended to this subject, wrote to me that 
he did not think that dark-coloured Europeans escaped 
the yellow-fever better than those that were light- 
coloured. Mr. J. M. Harris altogether denies 49 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 serve, there 
seems no foundation for the hypothesis, which has been 
accepted by several writers, that the colour of the black 
races may have resulted from darker and darker indi- 
viduals having survived in greater numbers, during 
their exposure to the fever-generating miasmas of their 
native countries. 

Although with our present knowledge we cannot 
account for the strongly-marked differences in colour 
between the races of man, either through correlation 
with constitutional peculiarities, or through the direct 
action of climate ; yet we must not quite ignore the 



" 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 indicating one means by which a race 
" of men inhabiting from a remote period an unhealthy tropical climate, 
" might have become dark-coloured by the better preservation of dark- 
" haired or dark-complexioned individuals during a long succession of 
" generations." 

49 ' Anthropological Review,' Jan. 18GG, p. xxi. 



246 THE DESCENT OF MAN. Part I. 

latter agency, for there is good reason to believe that 
some inherited effect is thus produced. 50 

We have seen in our third chapter that the condi- 
tions of life, such as abundant food and general comfort, 
affect in a direct manner the development of the bodily 
frame, the effects being transmitted. Through the 
combined influences of climate and changed habits of 
life, European settlers in the United States undergo, as 
is generally admitted, a slight but extraordinarily rapid 
change of appearance. There is, also, a considerable 
body of evidence shewing that in the Southern States 
the house-slaves of the third generation present a 
markedly different appearance from the field-slaves. 51 

If, however, we look to the races of man, as distri- 
buted over the world, we must infer that their charac- 
teristic 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 exclusively on animal food; they are 
clothed in thick fur, and are exposed to intense cold 
and to prolonged darkness ; yet they do not differ in 
any extreme degree from the inhabitants of Southern 
China, who live entirely on vegetable food and are ex- 
posed almost naked to a hot, glaring climate. The un- 
clothed Fuegians live on the marine productions of their 
inhospitable shores ; the Botocudos of Brazil wander 



50 See, for instance, Quatrefages ('Eevue des Cours Scientifiques,' 
Oct. 10, 1868, p. 724) on the effects of residence in Abyssinia and 
Arabia, and other analogous cases. Dr. Eolle ('Der Mensch, seine 
Abstammung,' &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 Quichuas in the Andes vary greatly in 
colour, according to the position of the valleys inhabited by them. 

51 Harlan, ' Medical Researches,' p. 532. Quatrefages (' Unite' de 
l'Espece Humaine,' 1861, p. 128) has collected much evidence on this 
head. 



Chap. VII. THE EACES OF MAN. 247 

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 Brazilians 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, are 
exposed 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, except to a quite insignificant degree, by 
the inherited effects of the increased or decreased use of 
parts. Men who habitually live in canoes, may have 
their legs somewhat stunted ; those who inhabit lofty 
regions have their chests enlarged ; and those who con- 
stantly use certain sense-organs have the cavities in 
which they are lodged somewhat increased in size, and 
their features consequently a little modified. With 
civilised nations, the reduced size of the jaws from 
lessened use, the habitual play of different muscles 
serving to express different emotions, and the increased 
size of the brain from greater intellectual activity, have 
together produced a considerable effect on their general 
appearance in comparison with savages. 52 It is also 
possible that increased bodily stature, with no corre- 
sponding increase in the size of the brain, may have 
given to some races (judging from the previously ad- 
duced cases of the rabbits) an elongated skull of the 
dolichocephalic type. 

Lastly, the little-understood principle of correlation 
will almost certainly have come into action, as in the 
case of great muscular development and strongly pro- 



52 See Prof. Schaaffhausen, translat. in 'Anthropological Keview,' 
Oct. 1868, p. 429. 



248 THE DESCENT OF MAN. Part I. 

jecting supra-orbital ridges. It is not improbable that 
the texture of the hair, which differs much iu the dif- 
ferent races, may stand in some kind of correlation with 
the structure of the skin ; for the colour of the hair 
and skin are certainly correlated, as is its colour and 
texture with the Mandans. 53 The colour of the skin 
and the odour emitted by it are likewise in some man- 
ner connected. With the breeds of sheep the number 
of hairs within a given space and the number of the 
excretory pores stand in some relation to each other. 54 
If we may judge from the analogy of our domesticated 
animals, many modifications of structure in man pro- 
bably come under this principle of correlated growth. 

We have now seen that the characteristic differences 
between the races of man cannot be accounted for in a 
satisfactory manner by the direct action of the condi- 
tions of life, nor by the effects of the continued use of 
parts, nor through the principle 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 
error on this head) not one of the external differ- 
ences between the races of man are of any direct or 



53 Mr. Catlin states (' N. American Indians,' 3rd edit. 1842, to] . i. p. 
49) that in the whole tribe of the Mandans, about one in ten or twelve 
of the members of all ages and both sexes have bright silvery grey hair, 
which is hereditary. Now this hair is as coarse and harsh as that of 
a horse's mane, whilst the hair of other colours is fine and soft. 

54 On the odour of the skin, Godron, ' Sur 1'Espece,' torn. ii. p. 217. 
On the pores in the skin, Dr. Wilckens, ' Die Aufgaben der landwirth. 
Zootechnik,' 1869, s. 7. 



Chap. VII. THE KACES OF MAN. 249 

special service to him. The intellectual and moral or 
social faculties must of course be excepted from this re- 
mark ; but differences in these faculties can have had 
little or no influence on external characters. The vari- 
ability of all the characteristic differences between the 
races, before referred to, likewise indicates that these 
differences cannot be of much importance ; for, had 
they been important, they would long ago have been 
either fixed and preserved, or eliminated. In this 
respect man resembles those forms, called by naturalists 
protean or polymorphic, which have remained extremely 
variable, owing, as it seems, to their variations being of 
an indifferent nature, and consequently to their having 
escaped the action 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 as 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 resi- 
duum is left, about which we can in our ignorance 
only say, that as individuals are continually born with, 
for instance, heads a little rounder or narrower, and 
with noses a little longer or shorter, such slight dif- 
ferences might become fixed and uniform, if the un- 
known agencies which induced them were to act in a 
more constant manner, aided by long-continued inter- 
crossing. Such modifications come under the provi- 
sional class, alluded to in our fourth chapter, which for 
the want of a better term have been called spontaneous 
variations. Nor do I pretend that the effects of sexual 
selection can be indicated with scientific precision ; but 
it can be shewn that it would be an inexplicable fact if 
man had not been modified by this agency, which has 



250 THE DESCENT OF MAN. Paet I. 

acted so powerfully on innumerable animals, both high 
and low in the scale. It can further be shewn that the 
differences between the races of man, as in colour, hairy- 
ness, form of features, &c, are of the nature which it 
might have been expected would have been acted on by 
sexual selection. But in order to treat this subject in a 
fitting manner, I have found it necessary to pass the 
whole animal kingdom in review ; I have therefore de- 
voted to it the Second Part of this work. At the close 
I shall return to man, and, after attempting to shew 
how far he has been modified through sexual selection, 
will give a brief summary of the chapters in this First 
Part, 



Part II. 



SEXUAL SELECTION. 



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 — Relations 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 — On the limita- 
tion of the numbers of the two sexes through natural selection. 

With animals which have their sexes separated, the 
males necessarily differ from the females in their organs 
of reproduction ; and these afford 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 reproduction; for 
instance, in the male possessing certain organs of sense 
or locomotion, of which the female is quite destitute, or 
in having them more highly-developed, in order that 
he may readily find or reach her ; or again, in the male 
having special organs of prehension so as to hold her 
securely. These latter organs of infinitely diversified 
kinds graduate into, and in some cases can hardly be 
distinguished from, those which are commonly ranked 
as primary, such as the complex appendages at the 
apex of the abdomen in male insects. Unless indeed 



254 THE PRINCIPLES OF Part II. 

we confine the term " primary ' : to the reproductive 
glands, it is scarcely possible to decide, as far as the 
organs of prehension are concerned, which ought to 
be called primary and which secondary. 

The female often differs from the male in having 
organs for the nourishment or protection of her young, 
as the mammary glands of mammals, and the ab- 
dominal sacks of the marsupials. The male, also, in 
some few cases differs from the female in possessing 
analogous organs, as the receptacles for the ova pos- 
sessed by the males of certain fishes, and those tem- 
porarily developed in certain male frogs. Female bees 
have a special apparatus for collecting and carrying 
pollen, and their ovipositor is modified into a sting for 
the defence of their larvae and the community. In the 
females of many insects the ovipositor is modified in 
the most complex manner for the safe placing of the 
eggs. Numerous similar cases could be given, but they 
do not here concern us. There are, however, other 
sexual differences quite disconnected with the primary 
organs with which we are more especially concerned — 
such as the greater size, strength, and pugnacity of the 
male, his weapons of offence or means of defence 
against rivals, his gaudy colouring and various orna- 
ments, his power of song, and other such characters. 

Besides the foregoing primary and secondary sexual 
differences, the male and female sometimes differ in 
structures connected with different habits of life, and 
not at all, or only indirectly, related to the reproductive 
functions. Thus the females of certain flies (Culicidae 
and Tabanidse) are blood-suckers, whilst the males live 
on flowers and have their mouths destitute of man- 
dibles. 1 The males alone of certain moths and of some 



* Westwood, 'Modern Class, of Insects,' vol. ii. 1840, p. 541. In 



Chap. VIII. SEXUAL SELECTION. 255 

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 hermaphrodite form, and are destitute of a mouth 
and prehensile limbs. In these cases it is the male 
which has been modified and has lost certain import- 
ant organs, which the females and other members of the 
same group possess. In other cases it is the female 
which has lost such parts ; for instance, the female glow- 
worm is destitute of wings, as are many female moths, 
some of which never leave their cocoons. Many female 
parasitic crustaceans have lost their natatory legs. In 
some weevil-beetles (Curculionidse) there is a great 
difference between the male and female in the length 
of the rostrum or snout ; 2 but the meaning of this and 
of many analogous differences, is not at all understood. 
Differences of structure between the two sexes in rela- 
tion to different habits of life are generally confined to 
the lower animals ; but with some few birds the beak 
of the male differs from that of the female. No doubt 
in most, but apparently not in all these cases, the dif- 
ferences are indirectly connected with the propagation 
of the species : thus a female which has to nourish a 
multitude of ova will require more food than the male, 
and consequently will require special means for procur- 
ing it. A male animal which lived for a very short 
time might without detriment lose through disuse its 
organs for procuring food ; 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, 



regard to the statement about Tanais, mentioned below, I am indebted 
to Fritz Muller. 

2 Kirby and Spence, 'Introduction to Entomology,' vol. iii. 1826, 
p. 309. 



256 THE PKINCIPLES OF Part II. 

or walking, if she gradually acquired habits which ren- 
dered such powers useless. 

We are, however, here concerned only with that kind 
of selection, which I have called sexual selection. This 
depends on the advantage which certain individuals have 
over other individuals of the same sex and species, in 
exclusive relation to reproduction. When the two sexes 
differ in structure in relation to different habits of life, 
as in the cases above mentioned, they have no doubt 
been modified through natural selection, accompanied 
by inheritance limited to one and the same sex. So 
again the primary sexual organs, and those for nourish- 
ing or protecting the young, come under this same head ; 
for those individuals which generated or nourished their 
offspring best, would leave, ceteris 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 search for the female, he requires for this purpose 
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. W T allace informs me that the males of cer- 
tain moths cannot unite with the females if their tarsi 
or feet are broken. The males of many oceanic crusta- 
ceans have their legs and antennae modified in an extra- 
ordinary manner for the prehension of the female ; 
h^nce we may suspect that owing to these animals 
being washed about by the waves of the open sea, they 
absolutely require these organs in order to propagate 
their kind, and if so their development will have been 
the result of ordinary or natural selection. 

W 7 hen the two sexes follow exactly the same habits 



Chap. VIII. SEXUAL SELECTION. 257 

of life, and the male has more highly developed sense 
or locomotive organs than the female, it may be that 
these in their perfected state are indispensable to the 
male for finding the female ; but in the vast majority 
of cases, they serve only to give one male an advan- 
tage over another, for the less well-endowed males, 
if time were allowed them, would succeed in pair- 
ing with the females ; and thev would in all other 
respects, judging from the structure of the female, be 
equally well adapted for their ordinary habits of life. 
In such cases sexual selection must have come into 
action, for the males have acquired their present struc- 
ture, not from being better fitted to survive in the 
struggle for existence, but from having gained an ad- 
vantage over other males, and from having transmitted 
this advantage to their male offspring alone. It was the 
importance of this distinction which led me to designate 
this form of selection as sexual selection. So again, 
if the chief service rendered to the male by his pre- 
hensile 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 acquired by 
certain males over their rivals. But in most cases it 
is scarcely possible to distinguish between the effects 
of natural and sexual selection. Whole chapters could 
easily be filled with details on the differences between 
the sexes in their sensorv, locomotive, and prehensile 
organs. As, however, these structures are not more 
interesting than others adapted for the ordinary pur- 
poses of life, I shall almost pass them over, 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 offence and the means of defence 

VOL. L s 



258 THE PRINCIPLES OF Part II. 

possessed by the males for fighting with and driving 
away their rivals — their courage and pugnacity — their 
ornaments of many kinds — their organs for producing 
vocal or instrumental music — and their glands for 
emitting odours; most of these latter structures serv- 
ing only to allure or excite the female. That these 
characters are the result of sexual and not of ordinary 
selection is clear, as unarmed, unornamented, or un- 
attractive males would succeed equally well in the 
battle for life and in leaving a numerous progeny, if 
better endowed males were not present. We may infer 
that this would be the case, for 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 they are in many respects in- 
teresting, but more especially as they depend 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 the strangest antics 
before an assembled bodv of females, we cannot doubt 
that, though led by instinct, they know what they are 
about, and consciously exert their mental and bodily 
powers. 

In the same manner as man can improve the breed 
of his game-cocks by the selection of those birds which 
are victorious in the cockpit, so it appeal's that the 
strongest and most vigorous males, or those provided 
with the best weapons, have prevailed under nature, 
and have led to the improvement of the natural breed 
or species. Through repeated deadly contests, a slight- 
degree of variability, if it led to some advantage, how- 
ever slight, would suffice for the work of sexual selec- 
tion ; and it is certain that secondarv sexual characters 



Chap; VIII. SEXUAL SELECTION. 259 

are eminently variable. In the same manner as man 
can give beauly, according to his standard of taste, to his 
male poultry — can give to the Sebright bantam a new 
and elegant plumage, an erect and peculiar carriage — 
so it appears that in a state of nature female birds, by 
having long selected the more attractive males, have 
added to their beauty. No doubt this implies powers 
of discrimination and taste on the part of the female 
which will at first appear extremely improbable; but 
I hope hereafter to shew that this is not the case. 

From our ignorance on several points, the precise 
manner in which sexual selection acts is to a certain 
extent uncertain. Nevertheless 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 
with almost all animals there is a struggle between the 
males for the possession of the female. This fact is so 
notorious that it would be superfluous to give instances. 
Hence the females, supposing that their mental capacity 
sufficed for the exertion of a choice, could select. one out 
of several males. But in numerous cases it appears as 
if it had been specially arranged that there should be 
a struggle between many males. Thus with migratory 
birds, the males generally arrive before the females at 
their place of breeding, so that many males are ready 
to contend for each female. The bird-catchers assert 
that this is invariably the case with the nightingale and 
blackcap, as I am informed by Mr. ^Tenner Weir, who 
confirms the statement with respect to the latter species. 

Mr. Swayslancl of Brighton, who has been in the habit, 
during the last forty years, of catching our migratory 
birds on their first arrival, writes to me that he has 
never known the females of any species to arrive before 

s 2 



260 THE PRINCIPLES OF Part II. 

their males. During one spring he shot thirty-nine 
males of Ray's wagtail (Budytes Baii) before he saw a 
single female. Mr. Gould has ascertained by dissection, 
as he informs me, that male snipes arrive in this 
country before the females ; but this hardly concerns us, 
as snipes do not breed here. In the case of fish, at the 
period when the salmon ascend our rivers, the males in 
large numbers are ready to breed before the females. 
So it apparently is with frogs and toads. Throughout 
the great class of insects the males almost always 
emerge from the pupal state before the other sex, so 
that they generally swarm for a time before any females 
can be seen. 3 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. 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. 

Our difficulty in regard to sexual selection lies in 
understanding 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 the beaten and less 



3 Even with those of plants in which the sexes are separate, the male 
flowers are generally mature before the female. Many hermaphrodite 
plants are, as first shewn by C. K. Sprengel, dichogamous ; that is, 
their male and female organs are not ready at the same time, so thai 
they cannot be self-fertilised. Now with such plants the pollen is 
generally mature in the same flower before the stigma, though there 
are some exceptional species in which the female organs are mature 
before the male. 



Chap. VIII. SEXUAL SELECTION. 261 

attractive males. Unless this result should follow, 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-endowed males will 
ultimately find females (except where polygamy pre- 
vails), and leave as many offspring, equally well fitted for 
their general habits of life, as the best-endowed males. 
From various facts and considerations, I formerly in- 
ferred that with most animals, in which secondary sexual 
characters are well developed, the males considerably 
exceeded the females in number; and this does hold 
good in some few cases. If the males were to the 
females 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 numerical propor- 
tions of the sexes, I do not believe that any great 
inequality in number commonly exists. In most cases 
sexual selection appears to have been effective in the 
following manner. 

Let us take any species, a bird for instance, and 
divide the females inhabiting a district into two equal 
bodies: the one consisting 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 during many years carefully attended to the habits 
of birds. There can also be no doubt that the most 
vigorous, healthy, and best-nourished females would on 
an average succeed in rearing the largest number of 
offspring. The males, as we have seen, are generally 
ready to breed before the females ; of the males the 



262 THE PRINCIPLES OF Part II. 

strongest, and with some species the best armed, drive 
away the weaker males ; and the former would then 
unite with the more vigorous and best-nourished fe- 
males, as these are the first to breed. Such vigorous 
pairs would surely rear a larger number of offspring 
than the retarded females, which would be compelled, 
supposing the sexes to be numerically equal, to unite 
with the conquered and less powerful males ; and tliis 
is all that is wanted to add, in the course of successive 
generations, to the size, strength and courage of the 
males, or to improve their weapons. 

But in a multitude of cases the males which conquer 
other males, do not obtain possession of the females, 
independently of choice on the part 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, as has been 
actually observed in some cases, that they would at the 
same time prefer the more vigorous and lively males. 4 
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 attractive. Such early 
pairs would have the same advantage in rearing off- 
spring on the female side as above explained, and nearly 
the same advantage on the male side. And this ap- 
parently has sufficed during a long course of generations 
to acid not only to the strength and fighting-powers of 



4 I have received information, hereafter to be given, to this effect 
with respect to poultry. 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. 



Chap. VIII. SEXUAL SELECTION. 263 

the males, but likewise to their various ornaments or 
other attractions. 

In the converse and much rarer case of the males 
selecting particular females, it is plain that those which 
were the most vigorous and had conquered others, would 
have the freest choice ; and it is almost certain that they 
would select vigorous as well as attractive females. Such 
pairs would have an advantage in rearing offspring, more 
especially if the male had the power to defend the 
female during the pairing-season, as occurs with some 
of the higher animals, or aided in providing for the 
young. The same principles would apply if both sexes 
mutually preferred and selected certain individuals of 
the opposite sex ; supposing that they selected not only 
the more attractive, but likewise the more vigorous 
individuals. 

Numerical Proportion of the Two Sexes. — I have 
remarked that sexual selection would be a simple 
affair if the males considerably exceeded in number 
the females. Hence I w 7 as led 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, retaining the details for a supplementary dis- 
cussion, so as not to interfere with the course of my 
argument. Domesticated animals alone afford the 
opportunity 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 considerable body of statistical data, from 
which it appears that with most^ of our domestic 
animals the sexes are nearly equal at birth. Thus with 
race-horses, 25,560 births have been recorded during 
twenty-one years, and the male births have been to the 
female births as 99*7 to 100. With greyhounds the 



264 THE PRINCIPLES OF Part II. 

inequality is greater than with any other animal, for 
during twelve years, out of 6878 births, the male births 
have been as HO'l to 100 female births. It is, however, 
in some degree doubtful whether it is safe to infer that 
the same proportional numbers would hold good under 
natural conditions as under domestication ; for slight 
and unknown differences in the conditions affect to a 
certain extent the proportion of the sexes. Thus with 
mankind, the male births in England are as 104*5, 
in Kussia as 108'9, and with the Jews of Livonia as 
120 to 100 females. The proportion is also mysteriously 
affected by the circumstance of the births being legiti- 
mate or illegitimate. 

For our present purpose we are concerned with the 
proportion of the sexes, not at birth, but at maturity, 
and this adds another element of doubt ; for it is a well 
ascertained fact that with man a considerably larger 
proportion of males than of females die before or during 
birth, and during the first few years of infancy. So it 
almost certainly is with male lambs, and so it may be 
with the males of other animals. The males of some 
animals kill each other by fighting ; or they drive 
each other about until they become greatly emaciated. 
They must, also, whilst wandering about in eager search 
for the females, be often exposed to various dangers. 
With 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. With some 
birds the females appear to die in larger proportion 
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 
devoured : in some cases the mature females are less 
active and less rapid in their movements than the males, 



Chap. VIII. SEXUAL SELECTIOX. 265 

and would not be so well able to escape from danger. 
Hence, with animals in a state of nature, in order to 
judge of the proportions of the sexes at maturity, we 
must rely on mere estimation ; and this, except perhaps 
when the inequality is strongly marked, is but little 
trustworthy. Nevertheless, 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, considerably 
exceed in number the females. 

The proportion between the sexes fluctuates slightly 
during successive years : thus with race-horses, for every 
100 females born, the males varied from 107*1 in one 
year to 92*0 in another year, and with greyhounds from 
116*3 to 95*3. But had larger numbers been tabulated 
throughout a more extensive area than England, these 
fluctuations would probably have disappeared ; and such 
as they are, they would hardly suffice to lead under 
a state of nature to the effective action of sexual selec- 
tion. Nevertheless with some few wild animals, the 
proportions seem, as shewn in the supplement, to fluc- 
tuate either during different seasons or in different 
localities in a sufficient degree to lead to such action. 
For it should be observed that any advantage gained 
during certain years or in certain localities by those 
males which were able to conquer other males, 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 every- 
where able to procure a female, the stronger or more 
attractive males previously produced would still have 
at least as good a chance of leaving offspring as the 
less strong or less attractive. 

Polygamy. — The practice of polygamy leads to the 



2G6 THE PKINCIPLES OF Part II. 

same results as would follow from au actual inequality 
in the number of the sexes ; for if each male secures 
two or more females, many males will not be able to 
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 between poly- 
gamy and the development of secondary sexual cha- 
racters, appears nearly certain; and this supports the 
view that a numerical preponderance of males would 
be eminently favourable to the action of sexual selection. 
Nevertheless many animals, especially birds, which are 
strictly monogamous, display stroDgly- marked secondary 
sexual characters ; whilst some few animals, which are 
polygamous, are not thus characterised. 

We will first briefly run through the class of mam- 
mals, and then turn to birds. The gorilla seems to be 
a polygamist, and the male differs considerably from 
the female ; so it is with some baboons which live in 
herds containing twice as many adult females as males. 
In South America the Mycetes car ay a presents well- 
marked sexual differences in colour, beard, and vocal 
organs, and the male generally lives with two or three 
wives : the male of the Cebus ca/pucinus differs some- 
what from the female, and appears to be polygamous. 5 
Little is known on this head with respect to most other 
monkeys, but some species are strictly monogamous. 
The ruminants are eminently polygamous, and they 



5 On the Gorilla, Savage and Wyinan, ' Boston Journal of Nat. Hist.' 
vol. v. 1845-47, p. 423. On Cynocephalus, Brehm, 'Illust. Thierleberi,' 
B. i. 1864, s. 77. On Mycetes, Kengger, 'Naturgeseh. : Saugethiere 
von Paraguay,' 1830, s. 14, 20. On Cebus, Brehin, ibid. s. 108. 



Chap. VIII. SEXUAL SELECTION. 207 

more frequently present sexual differences than almost 
any other group of mammals, especially in their weapons, 
but likewise in other characters. Most deer, cattle, and 
sheep are polygamous; as are most antelopes, though 
some of the latter are monogamous. 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 mature male. The Asiatic Antilope 
saiga appears to be the most inordinate polygamist 
in the world; for Pallas 6 states that the male drives 
away all rivals, and collects a herd of about a hundred, 
consisting of females and kids : the female is hornless 
and has softer hair, but does not otherwise differ much 
from the male. The horse is polygamous, but, except 
in his greater size and in the proportions of his body, 
differs but little from the mare. The wild boar, in his 
great tusks and some other characters, presents well- 
marked sexual characters ; in Europe and in India he 
leads a solitary life, except during the breeding-season ; 
but at this season he consorts in India with several 
females, as Sir W. Elliot, who has had large experience 
in observing this animal, believes : whether this holds 
good in Europe is doubtful, but is supported by some 
statements. The adult male Indian elephant, like the 
boar, passes much of his time in solitude; but when 
associating with others, "it is rare to find," as Dr. 
Campbell states, " more than one male with a whole 
< ; herd of females." The larger males expel or kill the 
smaller and weaker ones. The male differs from the 
female by his immense tusks and greater size, strength, 
and endurance ; so great is the difference in these latter 

6 Pallas, ' Spicilegia Zoolog/ Fasc. 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. 18l8, p. 633) 
gives a table incidentally showing which species of Antelopes pair and 
which are gregarious. 



268 THE PRINCIPLES OF Part II. 

respects, that the males when caught are valued at 
twenty per cent, above the females. 7 With other pachy- 
dermatous animals the sexes differ very little or not at 
all, and they are not, as far as known, polygamists. 
Hardly a single species amongst the Cheiroptera and 
Edentata, or in the great Orders of the Rodents and 
Insectivora, presents well-developed secondary sexual 
differences ; and I can find no account of any species 
being polygamous, excepting, perhaps, the common rat, 
the males of which, as some rat-catchers affirm, live 
with several females. 

The lion in South Africa, as I hear from Sir Andrew 
Smith, sometimes lives with a single female, but gene- 
rally with more than one, and, in one case, was found 
with as many as five females, so that he is polygamous. 
He is, as far as I can discover, the sole polygamist in 
the whole group of the terrestrial Carnivora, and he 
alone presents well-marked sexual characters. If, how- 
ever, we turn to the marine Carnivora, the case is widely 
different ; for many species of seals offer, as we shall 
hereafter see, extraordinary sexual differences, and they 
are eminently polygamous. Thus the male sea-ele- 
phant of the Southern Ocean, always possesses, accord- 
ing to Peron, several females, and the sea-lion of Forster 
is said to be surrounded by from twenty to thirty females. 
In the North, the male sea-bear of Steller is accom- 
panied by even a greater number of females. 

With respect to birds, many species, the sexes of 
which differ greatly from each other, are certainly 
monogamous. In Great Britain we see well-marked 
sexual differences in, for instance, the wild-duck which 
pairs with a single female, with the common blackbird, 



' Dr. Campbell, in ' Proc. Zoolog. Soc.' 1869, p. 138. See also an 
interesting paper, by Lieut. Johnstone, in ' Proc. Asiatic Soc. ofBeDgal,' 
May, 1868. 



Chap. VIII. SEXUAL SELECTION. 269 

and with the bullfinch which is said to pair for life. So 
it is, as I am informed by Mr. Wallace, with the Chat- 
terers or Cotingidoe of South America, and numerous 
other birds. In several groups I have not been able to 
discover whether the species are polygamous or mono- 
gamous. Lesson says that birds of paradise, so re- 
markable for their sexual differences, are polygamous, 
but Mr. Wallace doubts whether he had sufficient evi- 
dence. Mr. Salvin informs me that he has been led 
to believe that humming-birds are polygamous. The 
male widow-bird, remarkable for his caudal plumes, 
certainly seems to be a polygamist. 8 I have been 
assured by Mr. Jenner Weir and by others, that three 
starlings not rarely frequent the same nest ; but whether 
this is a case of polygamy or polyandry has not been 
ascertained. 

The Gallinaceae present almost as strongly marked 
sexual differences as birds of paradise or humming- 
birds, and many of the species are, as is well known, 
polygamous ; others being strictly monogamous. W T hat 
a contrast is presented between the sexes of the poly- 
gamous 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 mono- 
gamous red grouse and ptarmigan differ very little. 
Amongst the Cursores, no great number of species 
offer strongly - marked sexual differences, except the 
bustards, and the great bustard (Otis tarda), is said to 



8 ' The Ibis,' vol. iii. 1861, p. 133, on the Progne Widow-bird. Sot- 
also on the Vidua axillaris, ibid. vol. ii. 1860, p. 211. On the poly- 
gamy of the Capercailzie and Great Bustard, see L. Lloyd, ' Game Birds 
of Sweden,' 1867, p. 19, and 182. Montagu and Selby speak of the 
Black Grouse as polygamous and of the Bed Grouse as monogamous. 



270 THE PRINCIPLES OF Part II. 

be polygamous. With the Grallatores, extremely few 
species differ sexually, but the ruff" (Machetes pugnax) 
affords a strong exception, and this species is believed 
by Montagu to be a polygamist. Hence it appears 
that with birds there often exists a close relation 
between polygamy and the development of strongly- 
marked sexual differences. On asking Mr. Bartlett, at 
the Zoological Gardens, who has had such large ex- 
perience with birds, whether the male tragopan (one of 
the Gallinacere) was polygamous, I was struck by his 
answering, " I do not know, but should think so from 
" his splendid colours." 

It deserves notice that the instinct of pairing with a 
single female is easily lost under domestication. The 
wild-duck is strictly monogamous, the domestic-duck 
hiprhlv polv^amous. The Rev. W. D. Fox informs me 
that with some half-tamed wild-ducks, kept on a large 
pond in his neighbourhood, so many mallards were shot 
bv 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 two or three hens. 9 Canary-birds 
pair in a state of nature, but the breeders in England 
successfully put one male to four or five females ; never- 
theless the first female, as Mr. Fox has been assured, 
is alone treated as the wife, she and her young ones 
being fed by him ; the others are treated as concubines. 
I have noticed these cases, as it renders it in some 
degree probable that monogamous species, in a state of 
nature, might readily become either temporarily or per- 
manently polygamous. 



9 The Rev. E. S. Dixon, however, speaks positively (' Ornamental 
Poultry,' 1S48, p. 76) about the eggs of the guinea-fowl being infertile 
when more than one female is kept with the same male. 



Chap. VIII. SEXUAL SELECTION. 271 

With respect to reptiles and fishes, too little is known 
of their habits to enable ns to sj)eak of their marriage 
arrangements. The stickle-back G-asterosteus), however, 
is said to be a polygamist ; 10 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 develop- 
ment of secondary sexual characters. It has been shewn 
that the largest number of vigorous offspring will be 
reared from the pairing of the strongest and best-armed 
males, which have conquered other males, with the 
most vigorous and best-nourished females, which are 
the first to breed in the spring. Such females, if 
they select the more attractive, and at the same time 
vigorous, males, will rear a larger number of offspring 
than the retarded females, which must pair w r ith 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 especially hold good if the male defends 
the female, and aids in providing 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 lame 
preponderance in number of the males over the females 
would be still more efficient ; whether the preponder- 
ance was only occasional and local, or permanent; 
whether it occurred at birth, or subsequently from the 
greater destruction of the females ; or whether it in- 
directly followed from the practice of polygamy. 



TJie Male generally more modified than the Female. — 
Throughout the animal kingdom, when the sexes differ 



10 



Noel Humphreys, 'River Gardens,' 1857, 



272 THE PRINCIPLES OF Part II. 

from each other in external appearance, it is the male 
which, with rare exceptions, has been chiefly modified ; 
for the female still remains more like the young of her 
own species, and more like the other members of the 
same group. The cause of this seems to lie in the 
males of almost all animals having stronger passions 
than the females. Hence it is the males that fight 
together and sedulously display their charms before 
the females ; and those which are victorious transmit 
their superiority to their male offspring. Why the 
males do not transmit their characters to both sexes 
will hereafter be considered. That the males of all 
mammals eagerly pursue the females is notorious to 
every one. So it is with birds ; but many male birds 
do not so much pursue the female, as display their 
plumage, perform strange antics, and pour forth their 
song, in her presence. With the few fish which have 
been observed, the male seems much more eager than 
the female ; and so it is with alligators, and apparently 
with Batrachians. Throughout the enormous class of 
insects, as Kirby remarks, 11 " the law is, that the male 
" shall seek the female." With spiders and crustaceans, 
as I hear from two great authorities, Mr. Blackwall and 
Mr. C. Spence Bate, the males are more active and more 
erratic in their habits than the females. With insects and 
crustaceans, when the organs of sense or locomotion are 
present in the one sex and absent in the other, or when, 
as is frequently the case, they are more highly developed 
in the one than the other, it is almost invariably the male, 
as far as I can discover, which retains such organs, or has 
them most developed ; and this shews that the male is 
the more active member in the courtship of the sexes. 12 



11 Kirby and Spence, 'Introduction to Entomology,' vol. iii. 182G, 
p. 342. 

12 One parasitic Hymenopterous insect ("Westwood, ' Modern Class, 
of Insects,' vol. ii. p. 160) forms an exception to the rule, as the male 



Chap. VIII. SEXUAL SELECTION. 273 

The female, on the other hand, with the rarest excep- 
tion, is less eager than the male. As the illustrious 
Hunter 13 long ago observed, she generally " requires to 
" be courted ; " she is coy, and may often be seen en- 
deavouring for a long time to escape from the male. 
Everv one who has attended to the habits of animals 

af 

will be able to call to mind instances of this kind. 
Judging from various facts, hereafter to be given, and 
from the results which may fairly be attributed to 
sexual selection, 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 almost as 
general a law as the eagerness of the male. 

We are naturally led to enquire why the male in so 
many and such widely distinct classes has been ren- 
dered more easrer than the female, so that he searches 
for her and plays the more active part in courtship. 
It would be no advantage and some loss of power if 
both sexes were mutually to search for each other ; but 
why should the male almost always be the seeker ? 
With plants, the ovules after fertilisation have to be 
nourished for a time ; hence the pollen is necessarily 
brought to the female organs — being placed on the 
stigma, through the agency of insects or of the wind, 



has rudimentary wings, and never quits the cell in which it is born, 
whilst the female has well-developed wings. "- Audouin believes that 
the females 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, and thus avoid close interbreeding. We shall hereafter 
meet with a few exceptional cases, in various classes, in which the 
female, instead of the male, is the seeker and wooer. 

13 ' Essays and Observations,' edited by Owen, vol. i. 1861, p. 194. 

VOL. I. T 



274 THE PRINCIPLES OF Part II. 

or by the spontaneous movements of the stamens ; and 
with the Algae, &c, by the locomotive power of the 
antherozooids. With lowly-organised animals perma- 
nently affixed to the same spot and having their sexes 
separate, the male element is invariably brought to 
the female ; and we can see the reason why ; for the 
ova, even if detached before being fertilised and not 
requiring subsequent nourishment or protection, would 
be, from their larger relative size, less easily transported 
than the male element. Hence plants 14 and many of 
the lower animals are, in this respect, analogous. The 
males of affixed animals having been thus led to emit 
their fertilising element, it is natural that any of their 
descendants, which rose in the scale and became loco- 
motive, should retain the same habit, and should closely 
approach the female, so that the fertilising element 
might not run the risk of a long transit through the 
waters of the sea. With some few of the lower ani- 
mals, the females alone are iixed, and with these the 
males must be the seekers. With respect to forms, 
of which the progenitors were primordially free, it is 
difficult to understand why the males should inva- 
riably have acquired the habit of approaching the 
females, instead of being approached by them. But 
in all cases, in order that the males should be efficient 
seekers, it would be necessary that they should be en- 
dowed with strong passions ; and the acquirement of 
such passions would naturally follow from the more 
eager males leaving a larger number of offspring than 
the less eager. 

The great eagerness of the male has thus indirectly 



14 Prof. Sachs ('Lehrbuch der Botanik,' 1870, s. 633) in speaking of 
the male and ft male reproductive cells, remarks, " verlialt sich die eine 
" bei der Vereinigung activ, . . . die andere erscheint bei dur Verein- 
" igung passiv." 



Chap. VIII. SEXUAL SELECTION. 275 

led to the much more frequent development of secon- 
dary sexual characters in the male than in the female. 
But the development of such characters will have been 
much aided, if the conclusion at which I arrived after 
studying domesticated animals, can be trusted, namely, 
that the male is more liable to vary than the female. 
I am aware how difficult it is to verify a conclusion of 
this kind. Some slight evidence, however, can be gained 
by comparing the two sexes in mankind, as man has 
been more carefully observed than any other animal. 
During the Novara Expedition 15 a vast number of mea- 
surements of various parts of the body in different races 
were made, and the men were found in almost every 
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, 16 who has carefully 
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 thft greater frequency of deficiency in 
" females before described." Professor Macalister like- 
wise remarks 17 that variations in the muscles "are 
" probably more common in males than females." 
Certain muscles which are not normally present in man- 
kind are also more frequently developed in the male 
than in the female sex, although exceptions to this rule 



15 'Reise der Novara: Anthropolog. Tlieil,"* 1867, s. 21G-2G9. TJie 
results 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. 

16 'Proceedings Royal Soc.' vol. xvi. July, 18GS, p. :">19 and 524. 

17 < Proc. Royal Irish Academy,' vol. x. 1868, p. 123. 

rti •) 



276 THE PRINCIPLES OF Part II. 

are said to occur. Dr. Burt Wilder 18 has tabulated 
the cases of 152 individuals with supernumerary digits, 
of which 86 were males, and 39, or less than half, 
females ; the remaining 27 being of unknown sex. It 
should not, however, be overlooked that women would 
more frequently endeavour to conceal a deformity of 
this kind than men. Whether the large proportional 
number of deaths of the male offspring of man and 
apparently of sheep, compared with the female offspring, 
before, during, and shortly after birth (see supplement), 
has any relation to a stronger tendency in the organs 
of the male to vary and thus to become abnormal in 
structure or function, I will not pretend to conjecture. 

In various classes of animals a few exceptional cases 
occur, in which the female instead of the male has 
acquired well pronounced secondary sexual characters, 
such as brighter colours, greater size, strength, or pug- 
nacity. With birds, as we shall hereafter see, there 
has sometimes 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 apparently select- 
ing, as we may infer from the results, the more attractive 
females. Certain female birds have thus been rendered 
more highly coloured or otherwise ornamented, as well 
as more powerful and pugnacious than the males, these 
characters being transmitted to the female offspring 
alone. 

It may be suggested that in some cases a double 

J DO 

process of selection has been carried on ; the males 
having 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, 



13 'Massachusetts Medical Soc' vol. ii. No. 8, 1868, p. 9. 



Chap. VIII. SEXUAL SELECTION. 277 

would not make the one sex different from the other, 
unless indeed their taste for the beautiful differed; but 
this is a supposition too improbable in the case of any 
animal, excepting man, to be worth considering. There 
are, however, many animals, in which the sexes resemble 
each other, both being furnished with the same orna- 
ments, 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 females having selected the 
more attractive and vigorous males, the latter having 
rejected all except the more attractive females. But 
from what we know of the habits of animals, this view 
is hardly probable, the male being 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 off- 
spring 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 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 coloured or provided 
with special ornaments, and yet the members of both 
sexes or of one alone have probably been modified 
through sexual selection. 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 preferring simple colours, such as plain black 
or white. Obscure colours have often been acquired 
through natural selection for the sake of protection, and 



278 THE PRINCIPLES OF Part II. 

the acquirement through sexual selection of conspicuous 
colours, may have been checked from the danger thus 
incurred. But in other cases the males have probably 
struggled together during long ages, through brute 
force, or by the display of their charms, or by both 
means combined, and yet no effect will have been pro- 
duced unless a larger number of offspring were left by 
the more successful males to inherit their superiority, 
than by the less successful males ; and this, as previously 
ihewn, depends on various complex contingencies. 

Sexual selection acts in a less rigorous manner than 
natural selection. The latter produces its effects by the 
life or death at all ages of the more or less successful 
individuals. Death, indeed, not rarely ensues from the 
conflicts of rival males. But generally the less success- 
ful male merelv fails to obtain a female, or obtains a 
retarded and less vigorous female later in the season, 
or, if polygamous, obtains fewer females ; so that they 
leave fewer, or less vigorous, or no offspring. In re- 
gard to structures acquired through ordinary or natural 
selection, there is in most cases, as long as the condi- 
tions of life remain the same, a limit to the amount of 
advantageous modification in relation to certain special 
ends ; 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 
the frequent and extraordinary amount of variability 
presented by secondary sexual characters. Nevertheless, 
natural selection will determine that characters of this 
kind shall not be acquired by the victorious males, 
which would be injurious to them in any high degree, 
either by expending too much of their vital powers, or 



Chap. VIII. SEXUAL SELECTION. 279 

by exposing them to any great danger. The develop- 
ment, however, of certain structures — of the horns, for 
instance, in certain stags — has been carried to a 
wonderful extreme ; and in some instances 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 
favoured males have derived from conquering other 
males in battle or courtship, and thus leaving a 
numerous progeny, have been in the long run greater 
than those derived from rather more perfect adaptation 
to the external conditions of life. We shall further see, 
and this could never have been anticipated, that the 
power to charm the female has been in some few in- 
stances more important than the power to conquer other 
males in battle. 

LAWS OF INHERITANCE. 

In order to understand how sexual selection has 
acted, and in the course of ages has produced conspicuous 
results with many animals of many classes, it is neces- 
sary to bear in mind the laws of inheritance, as far as 
they are known. Two distinct elements are included 
under the term " inheritance," namely the transmission 
and the development of characters ; but as these 
generally go together, the distinction is often over- 
looked. We see this distinction 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 sexual characters, 
are crossed, for each transmits the characters proper to 



280 THE PRINCIPLES OF Part 11. 

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 deve- 
loped in the female when she grows old or becomes 
diseased ; and so conversely with the male. Again, 
characters occasionally appear, as if transferred from 
the male to the female, as when, in certain breeds of the 
fowl, spurs regularly appear in the young and healthy 
females ; but in truth they are simply developed in the 
female ; for in every breed each detail in the structure 
of the spur is transmitted through the female to her 
male offspring. In all cases of reversion, characters 
are transmitted through two, three, or many generations, 
and are then under certain unknown favourable con- 
ditions developed. This important distinction between 
transmission and development will be easiest kept in 
mind by the aid of the hypothesis of pangenesis, whether 
or not it be accepted as true. According to this hypo- 
thesis, 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 ; 
their development into units or cells, like those from 
wdiich they were derived, depending on their affinity 
for, and union with, other units or cells previously 
developed in the due order of growth. 

Inheritance at Corresponding Periods of Life. — This 
tendency is well established. If a new character appears 
in an animal whilst young, whether it endures through- 
out life or lasts only for a time, it will reappear, as a 
general rule, at the same age and in the same manner 
in the offspring. If, on the other hand, a new character 
appears at maturity, or even during old age, it tends 



Chap. VIII. SEXUAL SELECTION. 281 

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 discussed this subject 
at sufficient length in another work, 19 I will here merely 
give two or three instances, for the sake of recalling the 
subject to the reader's mind. In several breeds of the 
Fowl, the chickens whilst covered with down, the young 
birds in their first true plumage and in their adult plum- 
age, differ greatly from each other, as well as from their 
common parent-form, the Gallus bankiva ; and these 
characters are faithfully transmitted by each breed to 
their offspring at the corresponding period of life. For 
instance, the chickens of spangled Hamburghs, whilst 
covered with down, have a few dark spots on the head 
and rump, but are not longitudinally striped, 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. 20 Hence in this 
breed variations have occurred and have been trans- 
mitted at three distinct periods of life. The Pigeon offers 
a more remarkable case, because the aboriginal parent- 
species does not undergo with advancing age any change 
of plumage, excepting that at maturity the breast 
becomes more iridescent ; yet there are breeds which 
do not acquire their characteristic colours until they 



19 'The Variation of Animals and Plants under Domestication,' vol. 
ii. 1868, p. 75. In the latt chapter but one, the provisional hypothesis 
of pangenesis, above alluded to, is fully explained. 

20 These facts are given on the high authority of a great breeder, 
Mr. Teebay, in 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 above paragraph, see ' Variation of Animals,' 
&c, vol. i. p. 160, 249 ; vol. ii. p. 77. 



282 THE PRINCIPLES OF Part II. 

have moulted two, three, or four times ; and these 
modifications of* plumage are regularly transmitted. 

Inheritance at Corresponding Seasons of the Year. 
— With animals in a state of nature innumerable 
instances occur of characters periodically appearing at 
different seasons. We see this with the horns of the 
staar, and with the fur of arctic animals which becomes 
thick and white during the winter. Numerous birds 
acquire bright colours and other decorations during the 
breeding-season alone. I can throw but little light on 
this form of inheritance from fa r tts observed under 
domestication. Pallas states, 21 that in Siberia domestic 
cattle and horses periodically become lighter-coloured 
during the winter ; and I have observed a similar 
marked change of colour in certain ponies in England. 
Although I do not know that this tendency to assume a 
differently coloured coat durinff different seasons of the 
year is transmitted, yet it probably is so, as all shades of 
colour are strongly inherited by the horse. Nor is this 
form of inheritance, as limited by season, more remark- 
able than inheritance as limited by age or sex. 

Inheritance as Limited hy Sex. — The equal trans- 
mission 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 not 
rarely transferred exclusively to that sex, in which they 
first appeared. Ample evidence on this head has been 
advanced in my work on Variation under Domestica- 



21 'Novae species Quadrupedum e Glirium ordine,' 1778, p. 7. On 
the transmission of colour by the horse, see ' Variation of Animals, &c. 
under Domestication/ vol. i. p. 21. Also vol. ii. p. 71, for a general 
discussion on Inheritance as limited by Sex. 



Chap. VIII. SEXUAL SELECTION. 283 

tion ; 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 domes- 
tication, are regularly transmitted to the same sex. 
With tortoise-shell cats the females alone, as a general 
rule, are thus coloured, the males being rusty-red. 
With most breeds of the fowl, the characters proper 
to each sex are transmitted to the same sex alone. So 
general is this form of transmission that it is an ano- 
maly when we see in certain breeds variations trans- 
mitted equally to both sexes. There are also certain 
sub-breeds of the fowl in which the males can hardly 
be distinguished from each other, whilst the females 
differ considerably in colour. With the pigeon the 
sexes of the parent-species do not differ in any external 
character; nevertheless in certain domesticated breeds 
the male is differently coloured from the female. 22 
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 selection by man, 
the difference between the two sexes is wholly due to 
the form of inheritance which has prevailed ; for it 
has arisen, not from, but rather in opposition to, the 
wishes of the breeder. 

Most of our domestic races have been formed by the 
accumulation 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 diffe- 
rent breeds of the same species all gradations between 
great sexual dissimilarity and complete similarity. In- 



32 Dr. Cliapuis, ' Le Pigeon Voyageur Beige,' 1865, p. 87. Boitard 
et Corbie, « Les Pigeons de Voliere,' &c, 1824, p. 173. 



284 THE PEINCIPLES OF Part II. 

stances have already been given with the breeds of the 
fowl and pigeon ; and under nature analogous cases are 
of frequent occurrence. With animals under domesti- 
cation, but whether under nature I will not venture to 
say, one sex may lose characters proper to it, and may 
thus come to resemble to a certain extent the opposite 
sex ; for instance, the males of some breeds of the fowl 
have lost their masculine plumes and hackles. On the 
other hand the differences between 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 with those sub-breeds of the fowl in which the 
hens whilst young acquire spurs ; 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 intelligible on the hypothesis of pangenesis ; for 
they depend on the gemmules of certain units of the 
body, although present in both sexes, becoming through 
the influence of domestication dormant in the one sex ; 
or if naturally dormant, becoming developed. 

There is one difficult question which it will be con- 
venient to defer to a future chapter ; namely, whether 
a character at first developed in both sexes, can be ren- 
dered through selection limited in its development to 
one sex alone. If, for instance, a breeder observed that 
some of his pigeons (in which species 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 



Chap. VIII. SEXUAL SELECTION. 285 

to change his whole stock, including both sexes, into 
this tint, If, however, variations of the desired tint 
appeared, which were from the first limited in their 
development to the male sex, there would not be the 
least difficulty in making a breed characterised by the 
two sexes being of a different colour, 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, it would 
be easy to make a breed with the females alone thus 
characterised ; but if the variation was not thus originally 
limited, the process would be extremely difficult, per- 
haps impossible. 

On the Relation bettveen the period of Development of a 
Character and its transmission to one sex or to both sexes. 
— Why certain characters should be inherited by both 
sexes, and other characters 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 colour should, with rare exceptions, be 
developed in the female alone. The very same cha- 
racters, such as deficient or supernumerary digits, colour- 
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 the same sex. 23 Although we 
are thus ignorant, two rules often hold good, namely 



Zi Eefercnces are given in my ' Variation of Animals under Domes- 
tication,' vol. ii. p. 72. 



286 THE PRINCIPLES OF Part II. 

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 which 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 de- 
termining cause. As I have not elsewhere discussed 
this subject, and as it has an important 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 constitu- 
tion, before the power of reproduction is gained. On 
the other hand, after this power has been gained and the 
sexes have come to differ in constitution, the gemmules 
(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 with 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 has come to differ from the 
adult female, he differs in the same manner from the 
young of both sexes. The generality of this fact is quite 
remarkable : it holds good with almost all mammals, 
birds, amphibians, and fishes ; also with many crus- 
taceans, spiders and some few insects, namely certain 
orthoptera and libellulae. In all these cases the varia- 
tions, through the accumulation of which the male ac- 
quired his proper masculine characters, must have oc- 
curred at a somewhat late period of life ; otherwise the 
young males would have been similarly characterised ; 
and conformably with our rule, they are transmitted to 



Chap. VIII. SEXUAL SELECTION. 287 

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 
in conformity with our rule during youth. But there is 
here room for doubt, as characters are sometimes trans- 
ferred to the offspring at an earlier age than that at 
which they first appeared in the parents, so that the 
parents may have varied w r hen adult, and have trans- 
ferred their characters to their offspring whilst young. 
There are, moreover, many animals, 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 characters in apparent contradiction to our rule, 
are transferred to both sexes. We must not, however, 
overlook the possibility or even probability of succes- 
sive variations of the same nature sometimes occurring, 
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 corresponding late age ; and there would 
be no real contradiction to our rule of the variations 
which occur late in life being transferred exclusively to 
the sex in which they first appeared. This latter rule 
seems to hold true more generally than the second rule, 
namely, that variations which occur in either sex early 
in life tend to be transferred to both sexes. As it was 
obviously impossible even to estimate in how large a 
number of cases throughout the animal kingdom these 
two propositions hold good, it occurred to me to inves- 
tigate some striking or crucial instances, and to rely 
on the result. 



288 THE PRINCIPLES OF Part II. 

An excellent case for investigation is afforded by the 
Deer Family. In all the species, excepting one, the 
horns are developed in the male alone, though certainly 
transmitted through the female, and capable of occasional 
abnormal development in her. 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 had 
arrived at maturity and had come to differ much in 
constitution. In all the other species of deer the horns 
ought to appear later in life, leading to their develop- 
ment 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 periods 
varying from nine months after birth in the roebuck to 
ten or twelve or even more months in the stags of the 
six other larger species. 24 But with the reindeer the 
case is widely different, for as I hear from Prof. Nilsson, 
who kindly made special enquiries for me in Lapland, 
the horns appear in the young animals 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 common to both sexes in this one species. 

In several kinds of antelopes the males alone are 



24 I am much obliged to Mr. Cupples for having made enquiries for 
me in regard to the Roebuck and Red Deer of Scotland from Mr. 
Robertson, the experienced head-forester to the Marquis of Breadalbane. 
In regard to Fallow-deer, I am obliged to Mr. Eyton and others for 
information. For the Cervus dices of N. America, see ' Land and Water,' 
1868, p. 221 and 254; and for the C. Yirginianus and strongyloceros of 
the same continent, see J. D. Caton, in ' Ottawa Acad, of Nat. So.' 
1868, p. 13. For Cervus Eldi of Pegu, see Lieut. Beavan, ' Proc. 
Zoolog. Soc' 1867, p. 762. 



Chap. VIII. SEXUAL SELECTION. 289 

provided with horns, whilst in the greater number both 
sexes have horns. With respect to the period of de- 
velopment, Mr. Blvth informs me that there lived 
at one time in the Zoological Gardens a young koodoo 
(Ant. strepsiceros), in which species the males alone 
are horned, and the young of a closely-allied species, 
viz. the eland (Ant. oreas), in which both sexes are 
horned. Now in strict conformity with our rule, in the 
young male koodoo, although arrived at the age of ten 
months, 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 worth notice that in the prong-horned antelope, 25 
in which species the horns, though present in both 
sexes, are almost rudimentary in the female, they do not 
appear until about five or six months after birth. With 
sheep, goats, and cattle, in which the horns are well 
developed in both sexes, though not quite equal in size, 
they can be felt, or even seen, at birth or soon after- 
wards. 26 Our rule, however, fails in regard to some 
breeds of sheep, for instance merinos, in which the rams 
alone are horned ; for I cannot rind on enquiry, 27 that 



25 Antilocaiyra Americana. Owen, 'Anatomy of Vertebrates,' vol. 
iii. p. 627. 

2fi 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. 
With cattle Youatt says (' Cattle/ 1834, p. 277) that the prominence of 
the frontal bone penetrates the cutis at birth, and that the homy 
matter is soon formed over it. 

27 I am greatly indebted to Prof. Victor Cams 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 a 
breed of sheep in which, as with merinos, the rams alone bear horns ; 
and Mr. Winwood Eeade informs me that in the one case observed, a 
young ram born on Feb. 10th first showed horns on March Gth, so 
that in this instance the development of the horns occurred at a later 
VOL. I. U 



290 THE PRINCIPLES OF Part II. 

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 ; a certain proportion 
of the merino ewes bearing small horns, and some of the 
rams being hornless ; whilst with ordinary sheep hornless 
ewes are occasionally produced. 

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 pheasant (Crossoptilon 
auritum), however, offers a remarkable exception, for 
both sexes possess the fine caudal plumes, the large ear- 
tufts and the crimson velvet about the head ; and I find 
on enquiry in the Zoological Gardens that all these 
characters, in accordance with our rule, appear very 
early in life. The adult male can, however, be distin- 
guished from the adult female by one character, namely 
by the presence of spurs ; and conformably with our 
rule, these do not begin to be developed, as I am assured 
by Mr. Bartlett, before the age of six months, and even 
at this age, can hardly be distinguished in the two 
sexes. 28 The male and female Peacock differ con- 



period of life, conformably with our rule, than in the Welch sheep, in 
which both sexes are horned. 

28 In the common peacock (Paro cristatus) the male alone possesses 
spurs, whilst botli 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 in life 
than in the common peacock ; but M. Hegt of Amsterdam informs me, 
that with young birds of the previous year, belonging to 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 in- 
formed if any difference in the rate of development had subsequently 
been observed. 



Chap. VIII. SEXUAL SELECTION. 291 

spicuously from each other in almost every part of their 
plumage, 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 con- 
fined 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, 
whilst the curled tail-feathers and other ornaments 
peculiar to the male are developed later. 29 Between 
such extreme cases of close sexual resemblance and 
wide dissimilarity, as those of the Crossoptilon and 
peacock, many intermediate ones could be given, in 
which the characters follow in their order of develop- 
ment our two rules. 

As most insects emerge from their pupal state in a 
mature condition, it is doubtful whether the period of 
development determines the transference of their cha- 
racters to one or both sexes. But we do not know that 
the coloured scales, for instance, in two species of but- 
terflies, in one of which the sexes differ in colour, whilst 
in the other they are alike, are developed at the same 
relative age in the cocoon. Nor do we know whether 
all the scales are simultaneously developed on the wings 



29 In some other species of the Duck Family the speculum in the 
two sexes diners in a greater degree ; but I have not been able to dis- 
cover 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 differ conspicuously in 
general plumage, and to a considerable degree in the speculum, which 
is pure white in the male and greyish-white in the female. Now the 
young males at first resemble, in all respects, the female, and have a 
greyish-white speculum, but this becomes pure white at an earlier age 
than that at which the adult male acquires his other more strongly- 
marked sexual differences in plumage : see Audubon, ' Ornithological 
Biography,' vol. hi. 1835, p. 249-250. 

u 2 



292 THE PRINCIPLES OF Part II. 

of the same species of butterfly, in which certain coloured 
marks are confined to one sex, whilst other marks 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 distinc- 
tive masculine characters only during a later moult. 
Strictly analogous cases occur during the successive 
moults of certain male crustaceans. 

We have as yet only considered the transference of 
characters, relatively to their period of development, with 
species in a natural state ; we will now turn to domes- 
ticated animals ; first touching 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 colour- 
blindness — yet these peculiarities, and other similar 
ones, are often limited in their transmission to one sex ; 
so that the rule that characters which are 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 generally true as the 
converse proposition, namely, that characters which 
appear late in life in one sex are transmitted exclu- 
sively 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 a difference of some kind 
between the sexes at an extremely early age. With 
respect to sexually-limited diseases, we know too little 
of the period at which they originate, to draw any 
fair conclusion. Gout, however, seems to fall under 



GilAP. VIII. SEXUAL SELECTION. 293 

our rule ; for it is generally caused by intemperance 
after early youth, 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 development of their horns, forehead, 
mane, dewlap, tail, and hump on the shoulders; and 
these peculiarities, in accordance with our rule, are not 
fully developed until rather late in life. With dogs, 
the sexes 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 will account, 
according to our rule, for his increased size being trans- 
mitted to his male offspring alone. On the other hand, 
the tortoise-shell colour of the hair, which is confined 
to female cats, is quite distinct at birth, and this case 
violates our 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 pigeon the full develop- 
ment of the wattle and the crop occurs rather late in 
life, and these characters, conformably with our rule, 
are transmitted in full perfection to the males alone. 
The following cases perhaps come within the class pre- 
viouslv alluded to, in which the two sexes have varied 
in the same manner at a rather late period of life, and 
have consequently transferred their new characters to 
both sexes at a corresponding late period ; and if so, 
such cases are not opposed to our rule. Thus there 
are sub-breeds of the pigeon, described by Neumeis- 



294 THE PEINCIPLES OF Part II. 

ter, 30 both sexes of which change colour after moulting 
twice or thrice, as does likewise 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 
characters by one sex or by 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 colour from the female and 
from the adult male parent-species, he differs from the 
young male, so that the newly acquired characters must 
have appeared at a rather late period of life. On the 
other hand with most of the breeds in which the two sexes 
resemble each other, the young are coloured in nearly 
the same manner as their parents, and this renders it 
probable that their colours first appeared 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, leading to its 
transference to both sexes ; for the males alone of many 
natural species are either black or white, the females 
being very differently coloured. With the so-called 
Cuckoo sub-breeds of the fowl, in which the feathers are 
transversely pencilled with dark stripes, both sexes and 
the chickens are coloured in nearly the same manner. 
The laced plumage of the Sebright bantam is the same 
in both sexes, and in the chickens the feathers are tipped 
with black, which makes a near approach to lacing. 
Spangled Ham burghs, however, offer a partial exception, 



30 '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. 



Chap. VIII. SEXUAL SELECTION. 295 

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. Turning to other characters besides colour : 
the males alone of the wild parent-species and of most 
domestic breeds possess a fairly well developed comb, but 
in the young of the Spanish fowl it is largely developed 
at a very early age, and apparently in consequence of 
this it is of unusual size in the adult females. In the 
Game breeds pugnacity is developed at a wonderfully 
early age, of which curious proofs could be given ; and 
this character is transmitted to both sexes, so that the 
hens, from their extreme pugnacity, 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 ; 31 and in this breed a great bony protu- 
berance and an immense crest characterise the adults of 
both sexes. 

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 growth of the 
horns in the reindeer, in which both sexes have horns, 
in comparison with their much later growth in the 
other species in which the male alone bears horns 



31 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. p. 250, 256. In regard to the higher 
animals, the sexual differences which have arisen under domestication 
are described in the same work under the head of each species. 



296 THE PEINCIPLES OF Part II. 

— we may conclude that one cause, 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 efficient, cause of 
characters being inherited by both sexes is their deve- 
lopment 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 an 
early embryonic period, for characters developed at this 
age not rarely become attached to one sex. 

Summary and concluding remarks. — From the fore- 
going discussion on the various laws of inheritance, we 
learn that characters often or even generally tend to 
become developed in 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 
laws, from unknown causes, are very liable to change. 
Hence the successive steps in the modification of a 
species might readily be transmitted in different ways ; 
some of the steps being transmitted to one sex, 
and some to both; some to the offspring at one age, 
and some at all ages. Not only are the laws of inherit- 
ance extremely complex, but so are the causes which 
induce and govern variability. The variations thus 
caused are preserved and accumulated by sexual selec- 
tion, which is in itself an extremely complex affair, 
depending, as it does, on ardour in love, courage, and \ 
the rivalry of the males, and on the powers of percep- 
tion, taste, and will of the female. Sexual selection will 
also be dominated by natural selection for the general 
welfare of the species. Hence the manner in which the 
individuals of either sex or of both sexes are affected 
through sexual selection cannot fail to be complex in 
the highest degree. 



Chap. VIII. SEXUAL SELECTION. 297 

When variations occur late in life in one sex, and are 
transmitted to the same sex at the same age, the other 
sex and the young are necessarily left unmodified. 
When they occur late in life, but are transmitted to 
both sexes at the same age, the young alone are left un- 
modified. 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 will be similarly modified. In the following 
chapters it will be seen that all these cases frequently 
occur under nature. 

Sexual selection can never act on any animal be- 
fore the age for reproduction has arrived. 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 fight- 
ing with their rivals, or with organs for discovering 
and securely holding the female, or for exciting and 
charming her. When 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, have not generally occurred much before the 
age for reproduction. Whenever some or many of the 
variations have occurred early in life, the young males 
will partake in a less or greater degree of the cha- 
racters of the adult males. Differences of this kind 
between the old and young males may be observed 
with many animals, for instance with birds. 

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 in the acquisition of bright 
colours, which would have rendered them conspicuous 



298 THE PEINCIPLES OF Part II. 

to their enemies, or of structures, such as great horns, 
which would have expended much vital force in 
their development. Variations of this kind occurring 
in the young males will almost certainly have been 
eliminated through natural selection. With the adult 
and experienced males, on the other hand, the advan- 
tage derived from the acquisition of such characters, 
in their rivalry with other males, will often have 
more than counterbalanced exposure to some degree 
of clanger. 

As variations analogous to those wdrich give to the 
male a superiority over other males in fighting, or in 
finding, securing, or charming the opposite sex, would, 
if they happened to arise in the female, be of no service 
to her, they will not have been preserved through 
sexual selection in this sex. We have good evidence 
that with domesticated animals variations of all kinds 
are soon lost through intercrossing and accidental 
deaths, if not carefully selected. Consequently, varia- 
tions of the above kind, if they chanced to arise in 
the female, would be extremely liable to be lost ; 
and the females would be left unmodified, as far as 
these characters are concerned, excepting in so far 
as they were received through transference from the 
males. No doubt, if the females varied and trans- 
mitted their newly acquired characters to their off- 
spring of both sexes, the characters which were ad- 
vantageous to the males would be preserved through 
sexual selection, although they were of no use to 
the females themselves. In this case, both sexes would 
be modified in the same manner. But I shall here- 
after have to recur to these more intricate contin- 
gencies. 

Variations occurring late in life, and transmitted to 
one sex alone, have incessantly been taken advantage 



Chap. VIII. SEXUAL SELECTION. 299 

of and accumulated through sexual selection in rela- 
tion to the reproduction of the species ; therefore it 
appears, at first sight, an unaccountable fact that simi- 
lar variations have not frequently been accumulated 
through natural selection, in relation to ordinary habits 
of life. If this had occurred, the two sexes would fre- 
quently have been differently modified, for the sake, 
for instance, of capturing prey or of escaping from 
clanger. We have already seen and shall hereafter 
meet with other instances of differences of this kind 
between the two sexes, especially with the lower ani- 
mals; but they are rare in the higher classes. We 
should, however, bear in mind that the sexes in the 
higher classes generally follow the same habits of life ; 
and supposing that the males alone varied in a manner 
favouring their power of gaining subsistence, &c, and 
transmitted such variations to their male offspring 
alone, these would acquire an organization superior to 
that of the females ; but it is probable that the females, 
from having the same general constitution and from 
being exposed to the same conditions, would sooner or 
later vary in the same manner ; and as soon as this 
occurred, the variations would be equally preserved 
through natural selection in the two sexes, which would 
thus ultimately become like each other. The case is 
widely different with variations accumulated through 
sexual selection ; for the habits of the two sexes in 
relation to the reproductive functions are not the same, 
and sexually-transmitted modifications serviceable to 
the one sex would in it be preserved, whilst similar 
modifications would often be quite useless to the other 
sex, and consequently would in this latter soon be lost. 

In the following chapters, I shall treat of the 
secondary sexual characters in animals of all classes, 



300 THE PEINCIPLES OF Part II. 

and shall endeavour in each case to apply tbe prin- 
ciples 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 which the male conquers other males, 
and by which he allures or excites the female, will be 
fully discussed, as these are in many ways the most 
interesting. 



Supplement on the proportional members of the two sexes 
in animals belonging to various classes. 

As no one, as far as I can discover, has paid atten- 
tion to the relative numbers of the two sexes through- 
out the animal kingdom, I will here give such materials 
as I have been able to collect, although they are ex- 
tremely 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 on 
a large scale in the case of man alone, I will first give 
them, as a standard of comparison. 

Man. — In England during ten years (from 1857 to 
1866) 707,120 children on an annual average have 
been born alive, in the proportion of 104*5 males to 
100 females. But in 1857 the male births through- 
out England were as 105*2, and in 1865 as 104*0 to 
100. Looking to separate districts, in Buckinghamshire 
(where on an average 5000 children are annually born) 



Chap. VIII. SEXUAL SELECTION. 301 

the mean proportion 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 97'0 to 100; but 
even in this small district 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 England. 32 
The proportions are sometimes slightly disturbed by 
unknown causes ; thus Prof. Faye states " that in 
" some districts of Norway there has been during a 
" decennial period a steady deficiency of boys, whilst 
" in others the opposite condition has existed." In 
France 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 to 100. 33 It is a singular fact that 
with Jews the proportion of male births is decidedly 
larger than with Christians : thus in Prussia the propor- 
tion is as 113, in Breslau as 114, and in Livonia as 120 
to 100 ; the Christian births in these countries being 
the same as usual, for instance, in Livonia as 104 to 
100. 34 It is a still more singular fact that in different 
nations, under different conditions and climates, in 
Naples, Prussia, Westphalia, France and England, the 



32 ' Twenty-ninth Annual Report of the Registrar-General for 1866.' 
In this report (p. xii) a special decennial table is given. 

33 For Norway unci Russia, see abstract of Pro!'. Faye's researches, 
in ' British and Foreign Medieo-Cliirurg. Review/ April, 1867, p. 343, 
345. For France, the ' Annuaire pour lAn 1867,' p. 213, 

34 In regard to the Jews, see M. Thury, ' La Loi de Production dcs 
Sexes,' 1863, p. 25. 






302 THE PRINCIPLES OF Part II. 

excess of male over female births is less when they are 
illegitimate than when legitimate. 35 

In various parts of Europe, according to Prof. Faye 
and other authors, "a still greater preponderance of 

males would be met with, if death struck both sexes 

in equal proportion in the womb and during birth. 
" But the fact is, that for every 100 still-born females, 
" Ave have in several countries from 134*6 to 144*9 
" still-born males." Moreover during the first four or 
five years of life more male children die than females ; 
" for example in England, during the first year, 126 
" boys die for every 100 girls, — a proportion w r hich in 
" France is still more unfavourable." 36 As a consequence 
of this excess in the death-rate of male children, and of 
the exposure of men when adult to various dangers, and of 
their tendency to emigrate, the females in all old-settled 
countries, where statistical records have been kept, 37 are 
found to preponderate considerably over the males. 

It has often been supposed that the relative ages 
of the parents determine the sex of the offspring ; 
and Prof. Leuckart 38 has advanced what he considers 



35 Babbage, • Edinburgh Journal of Science,' 1829, vol. i. p. 88 ; also 
p. 90, on still-born children. On illegitimate children in England, 
see ' Keport of Kegistrar-General for 1866,' p. xv. 

36 'British and Foreign Medico-Chirurg. Keview,' April, 1867, p. 
343. Dr. Stark also remarks (' Tenth Annual Keport of Births, Deaths, 
&c, in Scotland,' 1867, p. xxviii) that "'lhese examples may suffice 
" to shew 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." 

37 "With the savage Guaranys of Paraguay, according to the accurate 
Azara ('Voyages dans l'Ame'rique me'rid.' torn. ii. 1809, p. 60, 179), 
the women in proportion to the men are as 14 to 13. 

38 Leuckart (in Wagner, ' Handworterbuch der Phys.' B. iv. 1853, 
s. 774. 



Chap. VIII. SEXUAL SELECTION. 303 

sufficient evidence, with respect to man and certain 
domesticated animals, to shew that this is one impor- 
tant factor in the result. So again the period of 
impregnation has been thought to be the efficient cause ; 
but recent observations discountenance this belief. 
Again, with mankind polygamy has been supposed to 
lead to the birth of a greater proportion of female 
infants ; but Dr. J. Campbell 39 carefully attended to 
this subject in the harems of Siam, and he 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 our English 
race-horses, and we shall immediately see that their 
male and female offspring are almost exactly equal in 
number. 

Horses. — Mr. Tegetmeier has been so kind as to tabulate for me 
from the ' Eacing 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 have 
been 25,560, 40 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 con- 
sidered : 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 propor- 
tions vary in cycles, for the males exceeded the females during six 
successive years ; and the females exceeded the males during two 



39 Anthropological Eeview, April, 1870, p. cyiii. 

40 During the last eleven years a record has been kept of the number of 
mares which have proved barren or prematurely slipped their foals ; and it 
deserves notice, as shewing 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 born, and 743 mares failed to produce offspring. 
During 1867, 836 males and 902 females were born, and 794 mares failed. 



304 THE PRINCIPLES QF Part II. 

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. I may add that certain 
mares, and this holds good with certain cows and with women, 
tend to produce more of one sex than of the other ; Mr. Wright of 
Yeldersley House, informs me that one of his Arab mares, though 
put seven times to different horses, produced seven fillies. 

Dogs. — During a period of twelve years, from 1857 to 1868, the 
births of a large number of greyhounds, throughout England, have 
been sent to the ' Field ' newspaper ; and I am again indebted to 
Mr. Tegetmeier for carefully tabulating the results. The recorded 
births have been 6878, consisting of 3605 males and 3273 females, 
that is, in the proportion of HO'l 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 domes- 
ticated breeds is in some degree doubtful. Mr. Cupples has enquired 
from several great breeders of dogs, and finds that all without 
exception believe that females are produced in excess ; he suggests 
that this belief may have arisen from females being less valued and 
the consequent disappointment producing a stronger impression on 
the mind. 

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 proportions 
at birth. Moieover, I find that seveial 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 one 
or two years ; therefore the proportion of males would be somewhat 
greater at birth than at the age of castration. This is a remarkable 
coincidence with what occurs, as we have seen, with mankind, and 
both cases probably depend on some common cause. I have re- 
ceived returns from four gentlemen in England who have bred low- 
land sheep, chiefly Leicesters, during the last ten or 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 extending 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 



Chap. VIII. SEXUAL SELECTION. 305 



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 whether this would hold 
good at birth is doubtful, owing to the greater liability in the males 
to early death. 41 

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 944 males to 100 females. 
The Rev. W. D. Fox informs me that in 1867 out of 34 calves born 
on a farm in Derbyshire only one was a bull. Mr. Harrison Weir 
writes to me that he has enquired 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 Babbits for many years, 
and has noticed that a far greater number of bucks are produced 
than does. 

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. E. Elliot of Laighwood, informs me that a rat- 
catcher assured him that he had always found the males in 
great 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 ha: 
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 ;" 42 
and as the catching of these animals is a special occupation, the 
statement may perhaps be trusted. Sir A. Smith, in describing 
an antelope of S. Africa 43 (Kobus ettijosiprymnus), 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 ex- 
pelled from the herds, and Sir A. Smith says, that though he has 
himself never seen herds consisting of young males alone, others 
affirm that this does occur. It appears probable that the young 
males when expelled from the herd, would be likely to fall a prey 
to the many beasts of prey of the country. 



s 



41 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 attention to the pre- 
mature deaths of the males, — a statement subsequently confirmed by Mr. 
Aitchison and others. To this latter gentleman, and to Mr. Payan, I owe 
my thanks for the larger returns on sheep. 

42 Bell, < History .of British Quadrupeds,' p. 100. 

43 * Illustrations of the Zoology of S. Africa,' 1849, pi. 29. 

VOL. I. X 



306 THE PRINCIPLES OF Part II. 



BIKDS. 

With respect to the Fowl, I have received only one account, 
namely, that out of 1001 chickens of a highly-bred stock of Cochins, 
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 that the males are produced in excess, or that their 
lives are 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 consist of a male and 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 others 44 
are convinced that the males are generally the more numerous; and 
as the young males of many species resemble the females, the latter 
would naturally appear to be the most numerous. Large numbers 
of pheasants are reared by Mr. Baker of Leadenhall from eggs laid 
by wild birds, and he informs Mr. Jenner Weir that four or five 
males to one female are generally produced. An experienced ob- 
server remarks 45 that in Scandinavia 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 
hks 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, 46 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 enquiring from the dealers 
who receive at certain seasons large numbers of ruffs (Machetes 
puynax) was told that the males are much the most numerous. 
This same naturalist has also enquired for me from the bird- 
catchers, who annually catch an astonishing number of various small 
species alive 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 



41 Brehm (' Illust. Thievleben,' B. iv. s. 990) comes to the same con- 
clusion. 

45 On the authority of L. Lloyd, 'Game Birds of Sweden,' 1867, p. 12, 
132. 

4,5 'Nat. Hist, of Selbourne,' letter xxix. edit, of 1825, vol. i. p. 139. 



Chap. VIII. SEXUAL SELECTION. 307 

1 female, or at least as high as 5 to 3. 47 The males of the black- 
bird, he likewise maintained, were by far the most numerous, whe- 
ther caught by traps or by netting at night. These statements 
may apparently be trusted, because the 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 
common 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 should, 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 most 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 
38 females. With two other species the females were in excess : 
but the proportions apparently vary either during different seasons 
or in different localities ; for on one occasion the males of Cam- 
pylopterus hemileucurus were to the females as five to two, and 
on another occasion 48 in exactly the reversed ratio. As 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." 49 So again with the Quiscalus major, Mr. Gr. Taylor 50 
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 polygamist. 

FISH. 

With Fish the proportional numbers of the sexes can be ascertained 
only by catching them in the adult or nearly adult state; and there 



47 Mr. Jenner Weir received similar information, on making enquiries 
during the following year. To shew the number of chaffinches caught, I 
may mention that in 1869 there was a match., between two experts; and 
one man caught in a day 62, and another 40, male chaffinches. The greatest 
number ever caught by one man in a single day was 70. 
^ 18 'Ibis,' vol. ii. p. 260, as quoted in Gould's ' Trochilidac,' 1861, p. 52. 
For the foregoing proportions, I am indebted to Mr. Salvin for a table of 
his results. 

• ,9 'Ibis,' 1860, p. 137 ; and 1867, p. 369. 

50 ' Ibis,' 1862, p. 137. 

x 2 



308 THE PRINCIPLES OF Part II. 

are many difficulties in arriving at any just conclusion. 51 Infertile 
females might readily be mistaken for males, as Dr. Giintlier has 
remarked to me in regard to trout. With some species the males 
are believed to die soon after fertilising 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, 52 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 
the 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 Stormont field experi- 
ments, 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 attention to the vast disproportion of the 
" males to the females. We had at the outset at least ten males 
" to one female." Afterwards sufficient females 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." 53 This disproportion, no doubt, can be accounted 
for in part, but whether wholly is very doubtful, by the males 
ascending the rivers before the females. Mr. F. Buckland remarks 
in regard to trout, that " it is a curious fact that the males prepon- 
" derate very largely in number 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 numer- 
" ous than the females, or the latter seek safety by concealment 
" rather than flight." He then adds, that by carefully searching the 
banks, sufficient females for obtaining ova can be found. 54 Mr. H. 
Lee informs me that out of 212 trout, taken for this purpose in Lord 
Portsmouth's park, 150 were males and 62 females. 

With the Cyprinida} the males 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 



51 Leuckart quotes Bloch (Wagner, ' Handworterbuch der Phys.' B. iv . 
1853, s. 775), that with fish there are twice as many males as females. 

52 Quoted in the 'Farmer,' March 18, 1869, p. 369. 

53 'The Stormontfield Piscicultural Experiments,' 1866, p. 23. The 
' Field ' newspaper, June 29th, 1867. 

54 ' Land and Water,' 1868, p. 41. 



Chap. VIII. SEXUAL SELECTION. 30 D 

animal kingdom, of polyandry ; for the female whilst 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 spawning- 
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 situa- 
tion for a time, are superseded by other two males." 55 



INSECTS. 

In this class, the Lepidoptera alone afford the means of judging 
of the proportional numbers of the sexes ; for they have been col- 
lected 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 consulting 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. The same naturalist, however, 
informs me, that in the two yearly broods of the Ailanthus silk- 
moth {Borribyx 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 
have been much struck by the apparently enormous preponderance 
of the males. 56 Thus Mr. Bates, 57 in speaking of the species, no 
less than about a hundred in number, which inhabit the Upper 
Amazons, says that the males are much more numerous than the 
females, 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. 



55 Yarrell, ' Hist. British Fishes,' vol. i. 18-86, p. 307; on the Cyprians 
carjrio, 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. 

56 Leuckart quotes Meinecke (Wagner, ' Handworterbuch der Phys.' 
B. iv. 1853, s. 775) that with Butterflies the males are three or four times 
as numerous as the females. 

57 ' The Naturalist on the Amazons,' vol. ii. 1863, p. 228, 347. 



310 THE PRINCIPLES OF Part II. 

Walsh, who informed me of this statement, says that with P. 
turnus this is certainly the case. Jn South Africa, Mr. R. Trimen 
found the males in excess in 19 species ; 58 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 during seven years only 
five females. In the island of Bourbon, M. Maillard states that 
the males of one species of Papilio are twenty times as numerous 
as the females. 59 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 in number the males ; but this is perhaps the 
case with three South African species. Mr. Wallace 60 states that 
the females of Ornithoptera crcesus, 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, Guene'e 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 Societ}^ 61 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 habits 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 lost at the beginning of the season, and 
the females at the end, from the want of mates. 62 I cannot how- 
ever persuade myself that these causes suffice to explain the great 
excess of males in the cases, above ' given, of butterflies which are 
extremely common in their native countries. Mr. Stainton, who 
has paid such 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 most 



58 Four of these cases are given by Mr. Trimen in his ' Pdiopalocera 
Africse Australis.' 

50 Quoted by Trimen, ' Transact. Ent. Soc' vol. v. part iv. 1866, p. 330. 

60 ' Transact. Linn. Soc' vol. xxv. p. 37. 

61 ' Proc. Entomolog. Soc' Feb. 17th, 1868. 

6 " Quoted by Dr. Wallace in ' Proc. Ent. Soc' 3rd series, vol. v. 1867, 
p. 487. 



Chap. VIII. SEXUAL SELECTION. 311 

numerous. Several entomologists concur in this view. Mr. Double- 
day, however, and some others, take an oj3posite view, and are con- 
vinced that they have^ reared from the egg and caterpillar states a 
larger proportion of males than of females. 

Besides the more active habits of the males, their earlier emerg- 
ence from the cocoon, and their frequenting in some cases more 
open stations, other causes may be assigned for an apparent or real 
difference in the proportional numbers of the sexes of Lepidop- 
tera, when captured in the imago state, and when reared from the 
egg or caterpillar state. It is believed by many breeders in Italy, 
as 1 hear from Professor Canestrini, that the female caterpillar of 
the silk-moth suffers more from the recent disease than the male ; 
and Dr. Staudinger informs me that in rearing Lepidoptera more 
females die in the cocoon than males. With many species the 
female caterpillar is larger than the male, and a collector would 
naturally choose the finest specimens, and thus unintentionally 
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 largest ; and 
Professor Canestrini informs me that in Italy some breeders believe, 
though on insufficient evidence, that in the first brood of the 
Ailanthus silk-moth, the wasps destroy a larger number of the 
female than of the male caterpillars. Dr. Wallace further remarks 
that female caterpillars, from being larger than the males, require 
more time for their development and consume more food and mois- 
ture ; and thus they would be exposed 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 the 
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 indicates 
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 fwenty males may often be 
seen congregated round a female Elacliista rufocinerea. Jt is well 
known that if a virgin Lasiocainpa quercus or iiaturnia carpini 
be exposed in a cage, vast numbers of males collect round her, 
and if confined in a room will even come down the chimney to her. 



.312 THE PRINCIPLES OF Part II. 

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 under confinement. Mr. Trim en exposed in the Isle 
of Wight a box in which a female of the Lasiocampa had been 
confined on the previous day, and five males soon endeavoured 
to gain admittance. M. "Verreaux, in Australia, having placed 
the female of a small Bombyx in a box in his pocket, was fol- 
lowed by a crowd of males, so that about 200 entered the house 
with him. 63 

Mr. Doubleday has called my attention to Dr. Standi nger's 64 list 
of Lepidoptera, which gives the prices of the males and females of 
300 species or well-marked varieties of (Ehopalocera) butterflies. 
The prices for both sexes of the very common species are of 
course the same ; but with 114 of the rarer species they differ ; the 
males being in all cases, excepting one, the cheapest. On an ave- 
rage 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 number in the same 
proportion. About 2000 species or varieties of moths (Heterocera) 
are catalogued, those with wingless females being here excluded on 
account of the difference in habits of the two sexes : of these 2000 
species, 141 differ in price according to sex, the males of 130 being 
cheaper, and the males 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 butterflies in this 
priced list, Mr. Doubleday thinks (and no man in England has had 
more experience), that there is nothing in the habits of the 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 numbers of 
the males. But I am bound to add that Dr. Staudinger himself, as 
he informs me, is of a different opinion. He thinks that the less 
active habits of the females 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 under confinement 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 either 



63 Blanchard, ' Metamorphoses, Mceurs des Insectes,' 1868, p. 225-226, 
H4 ' Lepidopteren-Doubblettren Liste,' Berlin, No. x. 1866, 



Chap. VIII. SEXUAL SELECTION. 313 

from eggs or caterpillars, I have received only the few following 
crises : — 



Males, j Females. 

The Rev. J. Hellins 65 of Exeter reared, during 1868, 

imagos of 73 species, which consisted of .. .. 153 137 

Mr. Albert Jones of Eltham reared, during 1868, im- 
agos of 9 species, which consisted of 159 126 

During 1869 he reared imagos from 4 species, consist- 
ing 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 Pernyisent 

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 the above various sources of evidence, all 
pointing to the same direction, 1 infer that with mo.-t species of 
Lepidoptera, the males in the imago state generally exceed the 
females in number, whatever the proportions may be at their first 
emergence from the egg. 

\Y ith 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 unusual number of these b< etles appeared in one part of Ger- 
many, the females appeared to exceed the males as six so ©ne. 
With one of the Elateridas, the males are said to be much more 
numerous than the females, and " two or three are often found 
" united with one female , 66 so that here polyandry seems to prevail. 



65 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. ^ 

66 Giinther's 'Record of Zoological Literature,' 1867, p. 260. On^th^' N 
excess of female Lucanus, ibid. p. 250. On the males of Lucanus in Etftp,^*- 
land, Westwood, ' Modern Class, of Insects,' vol. i. p. 187. On the SingonKi^ q° 
ibid. p. 172. /> 




314 THE PRINCIPLES OF Part II. 

With Siagonium (Staphylinidae), in which the males are furnished 
with horns, " the females are far more numerous than the opposite 
" sex." Mr. Janson stated at the Entomological Society 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. 
In other Orders, from unknown causes, but apparently in some in- 
stances owing to parthenogenesis, the males of certain species have 
never been discovered or are excessively rare, as with several of the 
Cynipida?. 67 In all the gall-making Cynipida? 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 Cecidomyiia; (Diptera). 
With some common species of Saw-flies (Tenthredime) Mr. ¥. 
Smith has reared hundreds of specimens from larvae of all sizes, 
but has never reared a single male : on the other hand Curtis says, 68 
that with certain species (Athalia), bred by him, the males to the 
females were as six to one ; whilst exactly the reverse occurred with 
the mature insects of the same species caught in the fields. With 
the Neuroptera, Mr. Walsh states that in many, but by no means 
in all, the species of the Odonatous groups (Ephemerina), there is a 
great overplus of males : in the genus Heta?rina, 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 numerous, 
whilst in two other species, the females are twice or thrice as 
numerous as the males. In some European species of Psocus thou- 
sands of females may be collected without a single male, whilst 
with other species of the same genus both sexes are common. 69 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 here seen. 70 With most 
of these species (excepting, as I have heard, with the Tenthredina 3 ) 
there is no reason to suppose that the females are subject to parthe- 
nogenesis ; and thas we see how ignorant we are on the causes of the 
apparent discrepancy in the proportional numbers 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 care- 
fully attended to this class during many years, writes to me that 
the males from their more erratic habits are more commonly seen, 



67 Walsh, in 'The American Entomologist,' vol. i. 1869, p. 103. F. Smith, 
' Record of Zoological Literature,' 1867, p. 328. 

68 ' Farm Insects,' p. 45-46. 

69 ' Observations on N. American Neuroptera,' bv H. Hagen and B. D. 
Walsh, 'Proc. Ent. Soc. Philadelphia,' Oct. 1863, p. 168, 223, 239. 

70 ' Proc. Ent. Soc. London,' Feb. 17, 1868. 



Chap. VJII. SEXUAL SELECTION. 315 

and therefore appear to be the 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. 71 The small size of the males in comparison with 
the females, which is sometimes carried to an extreme degree, and 
their widely different appearance, may account in some instances 
for their rarity in collections. 72 

Some of the lower Crustaceans are able to propagate their kind 
asexually, and this will account for the extreme rarity of the males. 
With some other forms (as with Tanais and Cypris) there is reason 
to believe, as Fritz Muller informs me, that the male is much shorter- 
lived than the female, which, supposing the two sexes to be at first 
equal in number, would explain the scarcity of the males. On the 
other hand this same naturalist has invariably taken, on the shores 
of Brazil, far more males than females of the Diastylida? and of 
Cypridina ; 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 Muller found the males to be more numerous 
than the females. The reverse seems to be the case, according to 
the large experience of Mr. C. Spence Bate, with six common British 
crabs, the names of which he has given me. 

On the Tower of Natural Selection to regulate the pro- 
portional Numbers of the Sexes, and General Fertility. — 
In some peculiar cases, an excess in the number of one 
sex over the other might be a great advantage to a 
species, as with the sterile females of social insects, or 
with those animals in which more than one male is 
requisite to fertilise the female, as with certain cirri- 
pecles and perhaps certain fishes. An inequality be- 
tween the sexes in these cases might have been acquired 
through natural selection, but from their rarity they 
need not here be further considered. In all ordinary 



71 Another great authority in this class, Prof. Thorell of Upsala (' On 
European Spiders,' 1869-70, part i. p. 205) speaks as if female spiders were 
generally commoner than the males. 

"- See, on this subject, Mr. Pickard-Cambridge, as quoted in 'Quarterly 
Journal of Science,' 1868, p. 429. 



316 THE PRINCIPLES OF Part II. 

cases an inequality would be no advantage or disad- 
vantage to certain individuals more than to others ; and 
therefore it could hardly have resulted from natural 
selection. We must attribute the inequality to the 
direct action of those unknown conditions, which with 
mankind lead to the males being born in a somewhat 
larger excess in certain countries than in others, or 
which cause the proportion between the sexes to differ 
slightly in legitimate and illegitimate births. 

Let us now take the case of a species producing from 
the unknown causes just alluded to, an excess of one 
sex — we will say of males — these being superfluous and 
useless, or nearly useless. Could the sexes be equalised 
through natural selection ? We may feel sure, from all 
characters being variable, that certain pairs would pro- 
duce a somewhat less excess of males over females than 
other pairs. The former, supposing the actual number 
of the offspring to remain constant, would necessarily 
produce more females, and would therefore be more pro- 
ductive. On the doctrine of chances a greater number 
of the offspring of the more productive pairs would sur- 
vive ; and these would inherit a tendency to procreate 
fewer males and more females. Thus a tendency to- 
wards the equalisation of the sexes would be brought 
about. But our supposed species would by this process 
be rendered, as just remarked, more productive ; and 
this would in many cases be far from an advantage ; 
for whenever the limit to the numbers which exist, de- 
pends, not on destruction by enemies, but on the amount 
of food, increased fertility will lead to severer competi- 
tion and to most of the survivors being badly fed. In 
this case, if the sexes were equalised by an increase in 
the number of the females, a simultaneous decrease in 
the total number of the offspring would be beneficial ; 
and this, I believe, could be effected through natural 



Chap. VIII. SEXUAL SELECTION. 317 

selection in the manner hereafter to be described. The 
same train of reasoning is applicable in the above, 
as well as in the following case, if we assume that 
females instead of males are produced in excess, for 
such females from not uniting with males would be 
superfluous and useless. So it would be with poly- 
gamous species, if we assume the excess of females 
to be inordinately great. 

An excess of either sex, we will again say of the 
males, could, however, apparently be eliminated through 
natural selection in another and indirect manner, namely 
by an actual diminution of the males, without any in- 
crease of the females, and consequently without any 
increase in the productiveness of the species. From 
the variability of all characters, we may feel assured 
that some pairs, inhabiting any locality, would produce 
a rather smaller excess of superfluous males, but an 
equal number of productive females. When the off- 
spring from the more and the less male-productive 
parents were all mingled together, none would have any 
direct advantage over the others; but those that pro- 
duced few superfluous males would have one great 
indirect advantage, namely that their ova or embryos 
would probably be larger and finer, or their young 
better nurtured in the womb and afterwards. We see 
this principle illustrated with plants; as those which 
bear a vast number of seed produce small ones ; whilst 
those which bear comparatively few seeds, often produce 
large ones well-stocked with nutriment for the use of the 
seedlings. 73 Hence the offspring of the parents which 
had wasted least force in producing superfluous males 



' 3 I have often been struck with the fact, that in several species of 
Primula the seeds in the capsules which contained only a few were 
very much larger than the numerous seeds in the more productive 
capsules. 



318 THE PKINCIPLES OF Part II. 

would be the most likely to survive, and would inherit 
the same tendency not to produce superfluous males, 
whilst retaining their full fertility in the production of 
females. So it would be with the converse case of the 
female sex. Any slight excess, however, of either sex 
could hardly be checked in so indirect a manner. Nor 
indeed has a considerable inequality between the sexes 
been always prevented, as we have seen in some of the 
cases given in the previous discussion. In these cases 
the unknown causes which determine the sex of the 
embryo, and which under certain conditions lead to 
the production of one sex in excess over the other, have 
not been mastered by the survival of those varieties 
which were subjected to the least waste of organised 
matter and force by the production of superfluous indi- 
viduals of either sex. Nevertheless we may conclude 
that natural selection will always tend, though some- 
times inefficiently, to equalise the relative numbers of 
the two sexes. 

Having said this much on the equalisation of the 
sexes, it may be well to add a few remarks on the regula- 
tion through natural selection of the ordinary fertility 
of species. Mr. Herbert Spencer has shewn in an able 
discussion 74 that with all organisms a ratio exists be- 
tween what he calls individuation and genesis; whence 
it follows that beings which consume much matter or 
force in their growth, complicated structure or activity, 
or which produce ova and embryos of large size, or 
which expend much energy in nurturing their young, 
cannot be so productive as beings of an opposite nature. 
Mr. Spencer further shews that minor differences in fer- 
tility will be regulated through natural selection. Thus 
the fertility of each species will tend to increase, from 



r-i < 



Principles of Biology,' vol. ii. 18G7, chaps, ii.-xi. 



Chap. VIII. SEXUAL SELECTION. 319 

the more fertile pairs producing a larger number of off- 
spring, and these from their mere number will have the 
best chance of surviving, and will transmit their ten- 
dency to greater fertility. The only check to a con- 
tinued augmentation of fertility in each organism seems 
to be either the expenditure of more power and the 
greater risks run by the parents that produce a more 
numerous progeny, or the contingency of very numerous 
eggs and young being produced of smaller size, or less 
vigorous, or subsequently not so well nurtured. To 
strike a balance in any case between the disadvantages 
which follow from the production of a numerous pro- 
geny, and the advantages (such as the escape of at least 
some individuals from various dangers) is quite beyond 
our power of judgment. 

When an organism has once been rendered extremely 
fertile, how its fertility can be reduced through natural 
selection is not so clear as how this capacity was first 
acquired. Yet it is obvious that if individuals of a 
species, from a decrease of their natural enemies, were 
habitually reared in larger numbers than could be sup- 
ported, all the members would suffer. Nevertheless the 
offspring from the less fertile parents would have no 
direct advantage over the offspring from the more fer- 
tile parents, when all were mingled together in the 
same district. All the individuals would mutually tend 
to starve each other. The offspring indeed of the less 
fertile parents would lie under one great disadvantage, 
for from the simple fact of being produced in smaller 
numbers, they would be the most liable to extermina- 
tion. Indirectly, however, they wOuld partake of one 
great advantage ; for under the supposed condition of 
severe competition, when all were pressed for foofl, it is 
extremely probable that those individuals which from 
some variation in their constitution produced fewer eggs 



320 THE PRINCIPLES OF SEXUAL SELECTION. Part II. 

or young, would produce them of greater size or vigour ; 
and the adults reared from such eggs or young would 
manifestly have the best chance of surviving:, and 
would inherit a tendency towards lessened fertility. 
The parents, moreover, which had to nourish or provide 
for fewer offspring would themselves be exposed to a 
less severe strain in the struggle for existence, and 
would have a better chance of surviving. By these 
steps, and by no others as far as I can see, natural 
selection under the above conditions of severe com- 
petition for food, would lead to the formation of a new 
race less fertile, but better adapted for survival, than 
the parent-race. 



Chap. IX. SEXUAL SELECTION. 321 



CHAPTER IX. 

Secondary Sexual Characters in the Lower Classes of 

the Animal Kingdom. 

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

In the lowest classes the two sexes are not rarely united 
in the same individual, and therefore secondary sexual 
characters cannot be developed. In many cases in which 
the two sexes are separate, both are permanently at- 
tached to some support, and the one cannot search or 
strup-o-le for the other. Moreover it is almost certain 
that these animals have too imperfect senses and 
much too low mental powers to feel mutual rivalry, 
or to appreciate each other's beauty or other attrac- 
tions. 

Hence in these classes or sub-kingdoms, such as the 
Protozoa, Coelenterata, Echinodermata, Scolecida, true 
secondarv sexual characters do not occur ; and this fact 
agrees with the belief that such characters in the 
higher classes have been acquired through sexual selec- 
tion, which depends on the will, desires, 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 colour from the females ; but we have no 
reason to suppose that such differences have been 
augmented through sexual selection. 

VOL. I. Y 



322 SEXUAL SELECTION. Part II. 

Many of the lower animals, whether hermaphrodites 
or with the sexes separate, are ornamented with the 
most brilliant tints, or are shaded and striped in an 
elegant manner. This is the case with many corals 
and sea-anemonies (Actiniae), with some jelly-fish (Me- 
dusae, Porpita, &c), with some Planariae, Ascidians, 
numerous Star-fishes, Echini, &e. ; but we may conclude 
from the reasons already indicated, namely the union 
of the two sexes in some of these animals, the per- 
manently affixed condition of others, and the low 
mental powers of all, that such colours do not serve 
as a sexual attraction, and have not been acquired 
through sexual selection. With the higher animals 
the case is very different ; for with them when one sex 
is much more brilliantly or conspicuously coloured 
than the other, and there is no difference in the 
habits of the two sexes which will account for this 
difference, we have reason to believe in the influence 
of sexual selection ; and this belief is strongly con- 
firmed when the more ornamented individuals, which 
are almost always the males, display their attractions 
before the other sex. We may also extend this con- 
clusion to both sexes, when coloured alike, if their 
colours 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 gorgeous colours of many animals in the lowest 
classes ? It appears very doubtful whether such colours 
usually serve as a protection ; but we are extremely 
liable to err in regard to characters of all kinds in 
relation to protection, as will be admitted by every one 
who has read Mr. Wallace's excellent essay on this 
subject. It would not, for instance, at first occur to 
any one that the perfect transparency of the Medusae, 
or jelly-fishes, was of the highest service to them as a 



Chap. IX. SEXUAL SELECTION. 323 

protection ; but when we are reminded by Hackel that 
not only the medusas but many floating mollusca, crus- 
taceans, and even small oceanic fishes partake of this 
same glass-like structure, we can hardly doubt that 
they thus escape the notice of pelagic birds and other 
enemies. 

Notwithstanding our ignorance how far colour in 
many cases serves as a protection, the most probable 
view in regard to the splendid tints of many of the 
lowest animals seems to be that their colours are the 
direct result either of the chemical nature or the minute 
structure of their tissues, independently of any benefit 
thus derived. Hardly any colour is finer than that of 
arterial blood ; but there is no reason to suppose that 
the colour 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 pur- 
pose. So again with many animals, especially the lower 
ones, the bile is richly coloured ; thus the extreme 
beauty of the Eolidae (naked sea-slugs) is chiefly due, as 
I am informed by Mr. Hancock, to the biliary glands 
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 sup- 
poses 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 chemists, and which exhibit 
the most splendid colours, it would have been a strange 
fact if substances similarly coloured had not often 
originated, independently of any useful end being 
thus gained, in the complex laboratory of living 
organisms. 

y 2 



324 SEXUAL SELECTION. Part II. 

The sub-kingdom of the Mollusca. — Throughout this 
great division (taken in its largest acceptation) of the 
animal kingdom, secondary sexual characters, such as 
we are here considering, never, as far as I can discover, 
occur. Nor could they be expected in the three lowest 
classes, namely in the Ascidians, Polyzoa, and Brachio- 
pods (constituting the Molluscoida of Huxley), for most 
of these animals are permanently affixed to a support 
or have their sexes united in the same individual. In 
the Lamellibranchiata, or bivalve shells, hermaphro- 
ditism is not rare. In the next higher class of the 
Gasteropoda, or marine univalve shells, the sexes are 
either united or separate. But in this latter case the 
males never possess special organs for finding, securing, 
or charming: the females, or for fio-htino- with other 
males. The sole external difference between the sexes 
consists, as I am informed by Mr. Gwyn Jeffreys, in 
the shell sometimes differing a little in form ; for 
instance, the shell of the male periwinkle (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 reproduction or with the development of the ova. 

The Gasteropoda, though 'capable of locomotion and 
furnished with imperfect eyes, do not appear to be en- 
dowed with sufficient mental powers for the members 
of the same sex to struggle together in rivalry, and 
thus to acquire secondary sexual characters. Never- 
theless 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, 1 " Qui- 
" conque a eu l'occasion d'observer les amours cles lima- 



1 ' De l'Espece et cle la Class.' &c, 1869, p. 106. 



Chap. IX. MOLLUSCS. 325 

" cons, ne saurait mettre en doute la seduction deployee 
"dans les mouvements et les allures qui preparent et 
" accomplissent le double embrassement de ces her-* 
" maphrodites." These animals appear also susceptible 
of some degree of permanent attachment : an accurate 
observer, Mr. Lonsdale, informs me that he placed a 
pair of land-shells (Helix pomatia), one of which 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 returned, and apparently 
communicated the result of its successful exploration, 
for both then started along the same track and disap- 
peared over the wall. 

Even in the highest class of the Mollusca, namely the 
Cephalopoda or cuttle-fishes, in which the sexes are 
separate, secondary sexual characters of the kind which 
we are here considering, do not, as far as I can discover, 
occur. This is a surprising circumstance, as these 
animals possess highly-developed sense-organs and have 
considerable mental powers, as will be admitted by 
everv one who has watched their artful endeavours to 
escape from an enemy. 2 Certain Cephalopoda, however, 
are characterised 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 completely does the 
cast-off arm resemble a separate animal, that it was 
described by Cuvieras a parasitic worm under the name 



2 See, for instance, the account which I have given in my ' Journal 
of Kesenrches,' 1845. p. 7. 



326 SEXUAL SELECTION. Part II. 

of Hectocotyle. But this marvellous 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 coloured and shaped. The colours 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 sculpture of the shell depending on its manner of 
growth. The amount of light seems to a certain extent 
to be influential ; for although, as repeatedly stated by 
Mr. G-wyn Jeffreys, the shells of some species living at a 
profound depth are brightly coloured, yet we generally 
see the lower surfaces and the parts covered by the 
mantle less highly coloured than the upper and exposed 
surfaces. 3 In some cases, as with shells livino- ainono-st 
corals or brightly-tinted sea-weeds, the bright colours 
may serve as a protection. But many of the nudibranch 
mollusca, or sea-slugs, are as beautifully coloured as 
any shells, as may be seen in Messrs. Alder and Han- 
cock's magnificent work ; and from information kindly 
given me by Mr. Hancock, it is extremely doubtful 
whether these colours usually serve as a protection. 
With some species this may be the case, as with one 
which lives on the green leaves of algae, and is itself 
bright-green. But many brightly-coloured, white or 
otherwise conspicuous species, do not seek concealment; 
whilst again some equally conspicuous species, as well 
as other dull-coloured kinds, live under stones and in 



3 I have given ('Geolog. Observations on Volcanic Islands,' 1844, 
p. 53) a curious instance of the influence of light on the colours of 
a frondescent incrustation, deposited by the surf on the coast-rocks of 
Ascension, and formed by the solution of triturated sea-shells. 



Chap. IX. MOLLUSCS AND ANNELIDS. 327 

dark recesses. So that with these nudibranch molluscs, 
colour apparently 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 together, as do land-snails, many of which have 
extremely pretty shells. It is conceivable that two 
hermaphrodites, attracted by each others' greater beauty, 
might unite and leave offspring: which would inherit 
their parents' greater beauty. But with such lowly- 
organised creatures this is extremely improbable. Nor 
is it at all obvious how the offspring from the more 
beautiful pairs of hermaphrodites would have any ad- 
vantage, so as to increase in numbers, over the offspring 
of the less beautiful, unless indeed vigour and beauty 
generally coincided. We have not here a number of 
males becoming mature before the females, and the 
more beautiful ones selected by the more vigorous 
females. If, indeed, brilliant colours were beneficial 
to an hermaphrodite animal 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-kingdom of the Vermes : Class, Annelida {or Sea- 
worms). — In this class, although the sexes (when separate) 
sometimes differ 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 attributed to 
sexual selection. These animals, like those in the pre- 
ceding classes, apparently stand .too low in the scale, 
for the individuals of either sex to exert any choice in 
selecting a partner, or for the individuals of the same 
sex to struggle together in rivalry. 



328 SEXUAL SELECTIOX. Part II. 

Sub-kingdom of the Arthropoda: Class, Crustacea. — 
In this great class we first meet with undoubted se- 
condary sexual characters, often developed in a remark- 
able 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 consist- 
ing 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 consequently 
clo not concern us. In various crustaceans, belonging 
to distinct families, the anterior antennas are furnished 
with peculiar thread-like bodies, which are believed to 
act as smelling-organs, and these are much more nume- 
rous 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 smell- 
ing-threads has probably been acquired through sexual 
selection, by the better provided males having been the 
most successful in finding partners and in leaving off- 
spring. Fritz Miiller has described a remarkable dimor- 
phic species of Tanais, in which the male is represented 
by two distinct forms, never graduating into each other. 
In the one form the male is furnished with more 
numerous smel ling-threads, and in the other form with 
more powerful and more elongated chelae or pincers 
which serve to hold the female. Fritz Miiller suo-gests 
that these differences between the two male forms of the 
same species must have originated in certain individuals 
having varied in the number of the smelling-threads, 
whilst other individuals varied in the shape and size of 



Chap. IX. 



CRUSTACEANS. 



329 



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 when found, 
have left the greater number of 
progeny to inherit their respec- 
tive advantages. 4 

In some of the lower crusta- 
ceans, the right-hand anterior 
antenna of the male differs 
greatly in structure from the 
left-hand one, the latter re- 
sembling in its simple tapering 
joints the antennae of the fe- 
male. In the male the modi- 
fied antenna is either swollen 
in the middle or angularly bent, 
or converted (fig. 3) into an 
elegant, and sometimes wonder- 
fully complex, prehensile organ. 5 
It serves, as I hear from Sir J. 
Lubbock, to hold the female, 
and for this same purpose 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 " curiously zigzagged ' : in the 
males alone. 




Fig. 3. 



Labidocera Darwinii (from 
Lubbock). 



Part of right-hand anterior an- 
tenna of male, forming a pre- 
hensile organ. 

Posterior pair of thoracic legs of 
male. 

Ditto of female. 



4 ' 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. 

5 See Sir J. Lubbock in 'Annals, and Mag. of Nat. Hist.' vol. si. 
1853, pi. i. and x. ; and vol. xii. (185H) pi. vii. See also Lubbock in 
' Transact. Ent. Soc' vol. iv. new series, 1856-1858, p. 8. With respect 
to the zigzagged antenna? mentioned below, see Fritz Miiller, ' Facts 
and Arguments for Darwin ' 1869, p. 40, foot-note. 



330 



SEXUAL SELECTION. 



Part II. 



In the higher crustaceans the anterior legs form a 
pair of chelae or pincers, and these are generally 
larger in the male than in the female. In many species 
the chelae on the opposite sides of the body are of 
unequal size, tbe right-hand one being, as I am in- 




Fig. 4. Anterior part of body of Callianassa (from Milne-Edwards), showing the unequal 
and differently -constructed right and left-hand chela? of the male. 

N.B.— The artist by mistake has reversed the drawing, and made the left-hand chela 
the largest. 





Fig. 5. 



Fig. 6. 



Fig. 5. Second leg of male Orchestia Tucuratinga (from Fritz Miiller). 
Fig. 6. Ditto of female. 

formed by Mr. C. Spence Bate, generally, though not 
invariably, the largest. This inequality is often much 
greater in the male than in the female. The two chelae 
also often differ in structure (figs. 4 and 5, 6), the smaller 
one resembling that of the female. What advantage 



Chap. IX. CRUSTACEANS. 331 

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. The chelae 
are sometimes of such length and size that they cannot 
possibly be used, as I hear from Mr. Spence Bate, for 
carrying food to the mouth. In the males of certain fresh- 
water prawns (Palsemon) the right leg is actually longer 
than the whole body. 6 It is probable that the great size 
of one leg with its chelae may aid the male in fighting 
with his rivals ; but this use will not account for their 
inequality in the female on the opposite sides of the body. 
In Gelasimus, according to a statement quoted by Milne- 
Edwards, 7 the male and female live in the same burrow, 
which is worth notice, as shewing that they pair, and 
the male closes the mouth of the burrow with one of its 
chelae, which is enormously developed ; so that here it 
indirectly serves as a means of defence. Their main 
use, however, probably is to seize and to secure the 
female, and this in some instances, as with Gammarus, 
is known to be the case. The sexes, however, of the 
common shore-crab (Carcinus meenas), as Mr. Spence 
Bate informs me, unite directly after the female has 
moulted her hard shell, and 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 previously to the act of moulting, she could then 
be seized with impunity. 

Fritz Miiller states that certain species of Melita are 



6 See a paper by Mr. C. Spence Bate, with figures, iu ' Proc. Zoolog. 
Soc.' ]868, p. 3(J3 ; 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. 

7 ' Hist. Nat. des Crust.' torn. ii. 1837, p. 50. 



332 SEXUAL SELECTION. Part II. 

distinguished 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 processes probably 
resulted from those females which were the most 
securely held during the act of reproduction, having 
left the largest number of offspring. Another Bra- 
zilian amphipod (Orchestia Darwinii, fig. 7) is de- 
scribed by Fritz Miiller, as presenting a case of dimor- 
phism, like that of Tanais ; for there are two male 
forms, which differ in the structure of their chelae. 8 As 
chelae of either shape would certainly have sufficed to 
hold the female, for both are now used for this purpose, 
the two male forms probably originated, by some having 
varied in one manner and some in another ; both forms 
having derived certain special, but nearly equal advan- 
tages, from their differently shaped organs. 

It is not known that male crustaceans fisrht together 
for the possession of the females, but this is probable ; 
for with most animals when the male is larger than the 
female, he seems to have acquired his greater size by 
having conquered during many generations other males. 
Now Mr. 8pence Bate informs me that in most of the 
crustacean orders, especially in the highest or the 
Brachyura, the male is larger than the female; the 
parasitic genera, however, in which the sexes follow 
different habits of life, and most of the Entomostraca 
must be excepted. The chelae of many crustaceans are 
weapons well adapted for fighting. Thus a Devil-crab 
(Portunus puher) was seen by a son of Mr. Bate fighting 
with a Carcinus mmnas, and the latter was soon thrown 
on its back, and had every limb torn from its body. 



Fritz Miiller, ' Facts and Arguments for Darwin,' 1869, p. 25-28. 



Chap. IX. 



CRUSTACEANS. 



333 



When several males of a Brazilian Gelasimus, a species 
furnished with immense pincers, were placed together 
by Fritz Miiller in a glass vessel, they mutilated and 
killed each other. Mr. Bate put a large male Carcinus 








; j' !r^ r ^r r 













Kig. 7. Oichestia Darwinii (from Fritz IVIuller), showing the different ly-cm istriu ted 

chehe of the two male forms. 

mamas into a pan of water, inhabited by a female paired 
with a smaller male ; the Litter was soon dispossessed, 
but, as Mr. Bate adds, " if they fought, the victor)' 



334 SEXUAL SELECTION. Part II. 

" was a bloodless one, for I saw no wounds." This 
same naturalist separated a male sand-skipper (so com- 
mon on our sea- shores), Gammarus marinus, from its 
female, both of which were imprisoned in the same 
vessel with many individuals of the same species. The 
female being thus divorced joined her comrades. After 
an interval the male was again put into the same 
vessel and he then, after swimming about for a time, 
dashed into the crowd, and without anv fight-ins: at once 
took away his wife. This fact shews that in the Amphi- 
poda, an order low in the scale, the males and females 
recognise each other, and are mutually attached. 

The mental powers of the Crustacea are probably 
higher than might have been expected. Any one who 
has tried to catch one of the shore-crabs, so numerous 
on many tropical coasts, will have perceived how wary 
and alert they are. There is a large crab (Birgus 
latro), found on coral islands, which makes at the 
bottom of a deep burrow a thick bed of the picked 
fibres of the cocoa-nut. 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 turning round, extracts the albuminous 
core with its narrow posterior pincers. But these actions 
are probably instinctive, so that they would be per- 
formed as well by a young as by an old animal. 
The following case, however, can hardly be so con- 
sidered : a trustworthy naturalist, Mr. Gardner, 9 whilst 
watching a shore-crab (Gelasimus) making its burrow, 



9 'Travels in the Interior of Brazil,' 1846, p. 111. I have given, in 
my ' Journal of Researches,' p. 463, an account of the habits of the 



Birgos. 



Chap. IX. CRUSTACEANS. 335 

threw some shells towards the hole. One rolled in, 
and three other shells remained within a few inches of 
the mouth. In about live 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. 

With respect to colour which so often differs in the 
two sexes of animals belonging to the higher classes, 
Mr. Spence Bate does not know of any well-marked 
instances with our British crustaceans. In some cases, 
however, the male and female 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 ex- 
posed to the light. In a curious Bornean crab, which 
inhabits sponges, Mr. Bate could always distinguish the 
sexes by the male not having the epidermis so much 
rubbed off. Dr. Power tried to distinguish by colour 
the sexes of the species which inhabit the Mauritius, but 
always failed, except with one species of Squilla, pro- 
bably the S. stijlifera, the male of which is described as 
being " of a beautiful blueish-green," with some of the 
appendages cherry-red, whilst the female is clouded 
with brown and grey, " with the red about her much 
" less vivid than in the male." 10 In this case, we may 
suspect the agency of sexual selection. With Sa- 
phirina (an oceanic genus of Entomostraca, and there- 
fore low in the scale) the males are furnished with 



10 Mr. Oh. Fraser, in 'Proc. Zoolog. Soc.' 1869, p. 3. I am indebted 
to Mr. Bate for the statement from Dr. Power. 



336 SEXUAL SELECTION. Part II. 

minute shields or cell-like bodies, which exhibit beau- 
tiful changing colours ; these being absent in the 
females, and in the case of one species in both sexes. 11 
It would, however, be extremely rash to conclude that 
these curious organs serve merelv to attract the females. 

© Ml 

In the female of a Brazilian species of Gelasimus, the 
whole body, as I am informed by Fritz Muller, is of a 
nearly uniform greyish-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 colours are liable to 
change in the course of a few minutes — the white 
becoming dirty grey or even black, the green " losing 
much of its brilliancy." The males apparently are 
much more numerous than the females. It deserves 
especial notice that they do not acquire their bright 
colours until they become mature. They differ also 
from the females in the larger size of their chela?. 
In some species of the genus, probably 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 highly 
probable that the male in this species has become 
srailv ornamented in order to attract or excite the 
female. 

It has just been stated, that the male Gelasimus does 
not acquire his conspicuous colours until mature and 
nearly ready to breed. This seems the general rule in 
the whole class with the many remarkable difference^ 
in structure between the two sexes. We shall here- 
after find the same law prevailing throughout the great 
sub-kingdom of the Yertebrata, and in all cases it is 
eminently distinctive of characters which have been 



11 Clans, ' Die freilebendeu Copepoden/ 1863, s. 35. 



Chap. IX. SPIDERS. 337 

acquired through sexual selection. Fritz Miiller 12 gives 
some striking instances of this law ; thus the male 
sand-hopper (Orchestia) does not acquire his large 
claspers, which are very differently constructed from 
those of the female, until nearly full-grown ; whilst 
young his claspers resemble those of the female. Thus, 
again, the male Brachyscelus possesses, like all other 
amphipods, a pair of posterior antennae ; the female, 
and this is a most extraordinary circumstance, is desti- 
tute of them, and so is the male as long as he remains 
immature. 

Class, Araclmida (Spiders). — The males are often 
darker, but sometimes lighter than the females, as may 
be seen in Mr. Blackwall's magnificent work. 13 In 
some species the sexes differ conspicuously from each 
other in colour ; thus the female of Sjparassus sma- 
ragdulus is dullish-green ; whilst the adult male has 
the abdomen of a fine yellow, with three longitudinal 
stripes of rich red. In some species of Thomisus the 
two sexes closely resemble each other ; in others they 
differ much; thus in T. citreus the legs and body of 
the female are pale-yellow or green, whilst the front 
legs of the male are reddish-brown : in T. Jiorieolens, 
the legs of the female are pale-green, those of the 
male being ringed in a conspicuous manner with various 
tints. Numerous analogous cases could be given in the 
genera Epeira/Nephila, Philodromus, Theridion, Liny- 
phia, &c. It is often difficult to say which of the two 
sexes departs most from the ordinary coloration of the 
genus to which the species belong ; "but Mr. Blackwall 



f 

12 ' Facts and Arguments,' &c., p. 79. 

13 'A History of the Spiders of Great Britain,' 18<»1-G4. For thc 



following facts, see p. 102, 77, 8S. 
VOL. I. 



338 SEXUAL SELECTION. Part II. 

thinks that, as a general rule, it is the male. Both 
sexes whilst young, as I am informed by the same 
author, usually resemble each other; and both often 
undergo great changes in colour during their successive 
moults before arriving at maturity. In other cases 
the male alone appears to change colour. Thus the 
male of the above-mentioned brightly-coloured Spa- 
rassus at first resembles the female and acquires his 
peculiar tints only when nearly adult. Spiders are 
possessed of acute senses, and exhibit much intelli- 
gence. The females often shew, as is well known, the 
strongest affection for their eggs, which they carry 
about enveloped in a silken web. On the whole it 
appears probable that well-marked differences in colour 
between the sexes have generally resulted from sexual 
selection, either on the male or female side. But doubts 
may be entertained on this head from the extreme 
variability in colour of some species, for instance of 
Theridion lineatum, the sexes of which differ when 
adult ; this great variability indicates that their colours 
have not been subjected to any form of selection. 

Mr. Black wall does not remember to have seen the 
males of any species fighting together for the posses- 
sion of the female. Nor, judging from analogy, is this 
probable; for the males are generally much smaller 
than the females, sometimes to an extraordinary de- 
gree. 14 Had the males been in the habit of fighting 
together, they would, it is probable, have gradually 



14 Aug. Vinson ('Arane'ides des lies de la Ke'union,' pi. vi. figs. 1 
and 2) gives a good instance of the small size of the male in Epeira 
nigra. In this species, as I mny add, the male is testaceous and the 
female black with legs banded with red. Other even more striking 
cases of inequality in size between the sexes have been recorded 
C Quarterly Journal of Science,' 1868, July, p. 429); but I have not seen 
the original accounts. 



C;iai\ IX. SPIDERS AND MYEIAPODA. 339 

acquired greater size and strength. Mr. Blackwall Las 
sometimes seen two or more males on the same web 
with a single female ; but their courtship is too tedious 
and prolonged an affair to be easily observed. The male 
is extremely cautious in making his advances, as the 
female 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 devoured, a 
" sight which, as he adds, filled him with horror and 
" indignation." 15 

Westrino* has made the interesting discovery that 
the males of several species of Theridion 16 have the 
power of making a striclulating sound (like that made 
by many beetles and other insects, but feebler), whilst 
the females are quite 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 could be detected in 
the females. From the analogy of the Orthoptera and 
Homoptera, to be described in the next chapter, we 
may feel almost sure that the stridulation serves, as 
Westring remarks, either to call or to excite the 
female ; and this is the first case in the ascending scale 
of the animal kingdom, known to me, of sounds emitted 
for this purpose. 

Class, Myriapoda. — In neither of the two orders in 
this class, including the millipedes and centipedes, 

15 Kirby and Spence, ' Introduction to Entomology,' vol. i. ISIS, 
p. 280. 

16 Tberidion (Asagena, Sund.) serratipes, 4-punctatum et guttatum ; 
see Westrir.g, in Kroyer, ' Naturhist. Tidskrift,' vol. iv. 1842-1843, 
p. 319; and vol. ii. 1846-1849, p. 342. See, also, for other species, 
' Aruneui Svecicso,' p. 184. 

z 2 



340 SEXUAL SELECTION. Part II. 

can I find any well-marked instances of sexual dif- 
ferences such as more particularly concern us. In 
Glomeris limbata, however, and perhaps in some few 
other species, the males differ slightly in colour from 
the females; but this Glomeris is a highly variable 
species. In the males of the Diplopoda, the legs be- 
longing to one of the anterior segments of the body, or 
to the posterior segment, 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. It is 
a much more unusual circumstance, as we shall see 
when w^e treat of Insects, that it is the female in 
Lithobius which is furnished with prehensile appen- 
dages at the extremity of the body for holding the 
male. 17 



17 Walckenaer et P. Gervais. 'Hist. Nat. cles Insectes : Apteres,' 
torn. iv. 1847, p. 17, 19, 68. 



Chap. X. SEXUAL SELECTION. 341 



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 
understood — Difference in size between the sexes — Thysanura 

— Diptera — Hemiptera — Homoptera, musical Dowers possessed 
by the males alone — Orthoptera, musical instruments of the 
males, much diversified in structure; pugnacity; colours — 
Neuroptera, sexual differences in colour — Hymenoptera, pugnacity 
and colours — Coleoptera, colours ; 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 organs for locomotion, and often in 
their sense-organs, as in the pectinated and beauti- 
fully plumose antennae of the males of many species. 
In one of the Ephemerae, namely Chloeon, the male 
has great pillared eyes, of which the female is entirely 
destitute. 1 The ocelli are absent in the females of 
certain other insects, as in the Mutillida?, which are 
likewise destitute of wings. But we are chiefly con- 
cerned with structures by which one male is enabled 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 female, may be briefly passed over. 
Besides the complex structures at the apex of the abdo- 
men, which ought perhaps to be ranked as primary 



1 Sir J. Lubbock, 'Transact. Linnean Soc.' vol. xxv. 1866. p. 484. 
With respect to the Mutillidje see Westwood, ' Modern Class, of Insects^' 
vol. ii. p. 213. 



342 SEXUAL SELECTION. Part II. 

organs, 2 " it is astonishing," as Mr. B. D. Walsh 3 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 cor nidus (a neuropterous insect 
in some degree allied to the Dragon-flies, &c.) has im- 
mense curved jaws, many times longer than those of the 
female ; and. they are smooth instead of being toothed, 
by which means he is enabled to seize her without 
injury. 4 One of the stag-beetles 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 
(AmmojiMla) the jaws in the two sexes are closely 
alike, but are used for widely different purposes ; the 
males, as Professor Westwood observes, " are exceed- 
" ingly ardent, seizing their partners round the neck 
" with their sickle-shaped jaws ; " 5 whilst the females use 



2 These organs in the male often differ in closely-allied species, and 
afford excellent specific characters. But their importance, under a 
functional point of view, as Mr. K. 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, ' Gesehichte der Natur/ 
B. ii. 1843, s. 164; and Westwood, 'Transact. Ent. Soc' vol. iii. 1842, 
p. 195) of distinct species having been observed in union. Mr. 
MacLachlan informs me vide 'Stett. Ent. Zeitung,' 1867. s. 155) that 
when several species of Phryganidse, which present strongly-pronounced 
differences of this kind, were confined together by Dr. Aug. Meyer, 
they coupled, and one pair produced fertile ova. 

s ' The Practical Entomologist,' Philadelphia, vol. ii. May,^ 1867, 
p. 88. 

4 Mr. Walsh, ibid. p. 107. 

5 < Modern Classification of Insects/ vol. ii. 1840, p. 206, 205. Mr. 
Walsh, who called my attention to this double use of the jaws, says 
that he has repeatedly observed this fact. 



Chap. X. 



INSECTS. 



o i o 



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 females 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 (Hydro- 
porus) have their elytra 
punctured for the same ob- 
ject. 6 In the male of Crabro 
cribrarius (fig. 8.), it is the 
tibia which is dilated into a 
broad horny plate, with mi- 
nute membraneous dots, giv- 
ing to it a singular appear- 
ance like that of a riddle. 7 
In the male of Pen the (a 

genUS Of beetles) a few Of Fi S- 8. Crabro cribrarius. Upper figure 
,-. . , -,-, . . ' r.,1 male; lower figure, female. 

the middle joints ot the an- 

tennge are dilated and furnished on the inferior surface 




6 We have here a curious ana inexplicable cdse of dimorphism, for 
some of the females of four European species of Dytiscus, and of certain 
species of Iiydroporus, have their elytra smooth ; and no intermediate 
gradations between sulcated or punctured "and 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. hi. 1826, p. 305. 

7 Westwood, 'Modern Class.' vol. ii. p. 193. The following state- 
ment about Pentlie, and others in inverted commas, are taken from 
Mr. Walsh, ' Practical Entomologist,' Philadelphia, vol. ii. p. 88. 



3-14 



SEXUAL SELECTION. 



Part II. 



with cushions of hair, exactly like those on the tarsi of 
the Carabidse, " 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 enable them to embrace 
< ( the neck of the female." Lastly in 
the males of many insects, the legs 
are furnished with peculiar spines, 
knobs or spurs ; or the whole leg is 
bowed or thickened, but this is by 
no means invariably a sexual cha- 
racter ; or one pair, or all three 
pairs are elongated, sometimes to 
an extravagant length. 8 

In all the orders, the sexes of 
many species present differences, of 
which the meaning is not under- 
stood. One curious case is that of 
a beetle (fig. 9), the male of which 
has the left mandible much en- 
larged ; so that the mouth is greatly 
distorted. In another Carabidous 
beetle, the Eurygnathus, 9 we have 
the unique case, as far as known to 
Mr. Wollaston, of the head of the 
female beino; much broader and 
larger, though in a variable degree, 
than that of the male. Any number 

Fig. 9. Taphrodei-es distortus f j cageg 1( J be „i ven< TlieV 

(much enlarged). Upper > n * 

figure, male; lower figure, abound in the Lepidoptera : one 

of the most extraordinary is that 
certain male butterflies have their fore-legs more or 





s Kirby and Spence, ' Introduct.' &c, vol. iii. p. 332-336. 
9 'Insecta Maclerensia,' 1854, p. 20. 



Chap. X. INSECTS. 345 

less atrophied, with the tibiee and tarsi reduced to mere 
rudimentary knobs. The wings, also, in the two sexes 
often differ in neuration, 10 and sometimes considerably 
in outline, as in the Aricoris epitus, which was shown 
to me in the British Museum by Mr. A. Butler. The 
males of certain South American butterflies have tufts 
of hair on the margins of the wings, and. horny excres- 
cences on the discs of the posterior pair. 11 In several 
British butterflies, the males alone, as shewn by Mr. 
Wonfor. are in parts clothed with peculiar scales. 

The purpose of the luminosity in the female glow- 
worm is likewise not understood ; for it is very doubtful 
whether the primary use of the light is to guide the 
male to the female. It is no serious objection to this 
latter belief that the males emit a feeble light; for 
secondary sexual characters proper to one sex are often 
developed in a slight degree in the other sex. It is a 
more valid objection that the larvse shine, and in some 
species brilliantly : Fritz Miiller informs me that the 
most luminous insect which he ever beheld in Brazil, 
was the larva of some beetle. Both sexes of certain 
luminous species of Elater emit light. Kirby and 
Spence suspect that the phosphorescence serves to 
frighten and drive away enemies. 

Difference in Size between the Sexes. — With insects 
of all kinds the males are commonly smaller than the 
females ; 12 and this difference can often be detected, 
even in the larval state. So considerable is the difference 



10 E. Doubleday, 'Annals and Mag. of Nat. Hist.' vol. i. 1848, p. 371*. 
I may add that the wings in certain Hymen optera (see Shuckard, 
Tossorial Hymenup.' 18:37, p. 39-43) differ in neuration according to 
sex. 

11 H. W. Bates, in ' Journal of Proc. Linn. Soc." vol. vi. 1862, 
Mr. Wonfor 's observations are quoted in ' Popidar Science, 
1868, p. 343. /<^Q° S H 6 

12 Kirliv and Spence, ' Introduction to Entomologv,' vol/^H\*Zo9. A .^ 4 

LIBRAR 



34(5 SEXUAL SELECTION. Pakt II. 

between the male and female cocoons of the silk-moth 
(Bombyx mori), that in France they are separated by 
a particular mode of weighing. 13 In the lower classes 
of the animal kingdom, the greater size of the females 
seems generally to depend on their developing an enor- 
mous 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 
of some dwarfed caterpillars reared from a second brood 
on unnatural food, "that in proportion as the indivi- 
" dual 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." 14 Now 
as most insects are short-lived, and as they are exposed 
to many dangers, it w T ould manifestly be advantageous 
to the female to be impregnated 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, 15 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 matured 
later would leave fewer offspring. 

There are, however, exceptions to the rule of male 
insects being smaller than the females; and some of 



13 Kobinet, ' Vers a Soie,' 1848, p. 207. 

14 ' Transact. Ent. Soc.' 3rd series, vol. v. p. 486. 

15 < Journal of Proc. Ent. Soc' Feb. 4th, 1867, p. lxxi. 



Chap. X. INSECTS. 347 

these exceptions are intelligible. Size and strength 
would be an advantage to the males, which fight for the 
possession of the female ; and in these cases the males, 
as with the stag-beetle (Lucanus), are larger than the 
females. There are, however, other beetles which are 
not known to fio-ht Wether, 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-flies (Libellulidse) are sometimes sensibly 
larger, and never smaller, than the females ; 16 and 
they do not, as Mr. MacLachlan believes, generally 
pair with the females, until a week or fortnight has 
elapsed, and until they have assumed their proper 
masculine colours. But the most curious case, shewing 
on what complex and easily-overlooked relations, so 
trifling a character as a difference in size between the 
sexes may depend, is that of the aculeate Hymenoptera ; 
for Mr. F. Smith informs me that throughout nearly 
the whole of this large group the males, in accor- 
dance with the general 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 aeervorum, and amongst the 
Fossores, the males of the Methoca ichneumonides, are 
larger than the females. The explanation of this ano- 
maly is that a marriage-flight is absolutely necessary 



16 For this and other statements on the size of the sexes, see Kirhy 
and Spenoe, ibid. vol. iii. p. 300 ; on the duration of life in insects, 
see p. 314. 



348 SEXUAL SELECTION. Part II. 

with these species, and the males require great strength 
and size in order to carry the females through the air. 
Increased size has here been acquired in opposition to 
the usual relation between size and the period of de- 
velopment, for the males, though larger, emerge before 
the 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, Thysanura.—The members of this Order are 
lowly organised for their class. They are wingless, 
dull-coloured, minute insects, with ugly, almost mis- 
shapen heads and bodies. The sexes do not differ ; but 
they offer one interesting fact, by shewing that the males 
pay sedulous court to their females even low down in the 
animal scale. Sir J. Lubbock 17 in describing the Smyn- 
thurm liiteus, says : " it is very amusing to see these 
" little creatures 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 
colour. The greatest difference, known to Mr. F. Walker, 



" ' Transact. Linnean Soc.' vol. xxvi. 1868, p. 296. 



Chap. X. DIPTERA AND HEMTPTERA. 349 

is in the genus Bibio, in which the males are blackish 
or quite black, and the females obscure brownish-orange. 
The genus Elaphomvia, discovered by Mr. Wallace 18 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 stags, being either branched 
or palmated. They equal in length the whole of the 
body in one of the species. They might be thought 
to serve for fighting, but as in one species they are 
of a beautiful pink colour, edged with black, with a 
pale central stripe, and as these insects have altogether 
a very elegant appearance, it is perhaps more pro- 
bable that the horns serve as ornaments. That the 
males of some Diptera fight together is certain ; for 
Prof. Westwoed 19 has several times seen this with some 
species of Tipula or Harry-long-legs. Many observers 
believe that when gnats (Culickke) dance in the air in 
a body, alternately rising and falling, the males are 
courting the females. The mental faculties of the 
Diptera are probably fairly well developed, for their 
nervous system is more highly developed than in most 
other Orders of insects. 20 

Order, He?niptera (Field-Bugs). — Mr. J. W. Douglas, 
who has particularly attended to the British species, has 
kindly aiven me an account of their sexual differences. 
The males of some species are furnished with wings, 
whilst the females are windless ; the sexes differ in the 
form of the body and elytra ; in the second joints of 
their antennae and in their tarsi ; but as the signification 



18 « The Malay Archipelago,' vol. ii. 1809, p. 313. 

19 ' Modern Classification of Insects,' vol. ii. 1840, p. 526. 

30 See Mr. B. T. Lowne's very interesting work, ' On the Anatomy of 
the Blow-Fly, Mnsca vomitoria,' 1870, p. 14. 



350 SEXUAL SELECTION. Part II. 

of these differences is quite 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 colour; 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 marked with vermilion and black. It is 
doubtful whether these colours serve as a protection. 
If in any species the males had differed from the females 
in an analogous manner, we might have been justified 
in attributing such conspicuous colours to sexual selec- 
tion with transference to both sexes. 

Some species of Keduvidae make a stridulating noise ; 
and, in the case of Pirates stridulus, this is said 21 to 
be effected by the movement of the neck within the 
pro-thoracic cavity. According to Westring, Beduvius 
personatus also stridulates. But I have not been able 
to learn any particulars about these insects ; nor have I 
any reason to suppose that they differ sexually in this 
respect. 

Order, Homojrfera. — Every one who has wandered in 
a tropical forest must have been astonished at the din 
made by the male Cicadaa. 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 



21 Westwocd, ' Modern Class, of Insects,' vol. ii. p. 473. 



Chap. X. HOMOPTEKA. 351 

in caires for the sake of their sods:, so that it must be 
pleasing to the ears of some men. 22 The Cicadida3 
usually sing during the day ; whilst the Fulgoridaa 
appear to be night-songsters. The sound, according 
to Landois, 23 who has recently studied the subject, 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. It is increased by a wonderfully 
complex resounding apparatus, consisting of two cavi- 
ties covered by scales. Hence the sound may truly 
be called a voice. In the female the musical apparatus 
is present, but very 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 sejrfemdecim of the United 
States, says, 24 " the drums are now (June 6th and 7th, 
" 1851) heard in all directions. 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 to alight near a 
" male while he was uttering his clanging notes." Fritz 
Miiller writes to me from S. Brazil that he has often 
listened to a musical contest between two or three 
males of a Cicada, having a particularly loud voice, and 
seated at a considerable distance from each other. As 



22 These particulars are taken from Westwood's ' Modern Class, of 
Insects' v«l. ii. 1840, p. 422. See, also, on the Fulgoridse, Kirby and 
Spciice, Introduce' vol. ii. p. 401. 

23 ' Zeitschrift fiir wissenschait. Zcolog.' B. xvii. 1867. s. 152-158. 

21 lam indebted to Mr. Walsh for having sent me this extract from 
a ' Journal of the Doings of Cicada septemdecim,' by Dr. Hartman. 



352 SEXUAL SELECTION. Part II. 

soon as the first had finished his sonp\ a second im- 
mediately began ; and after he had concluded, another 
began, and so on. As there is so much rivalry between 
the males, it is probable that the females not only dis- 
cover them by the sounds emitted, but that, like female 
birds, they are excited or allured by the male with the 
most attractive voice. 

I have not found any well-marked cases of orna- 
mental differences between the sexes of the Homoptera. 
Mr. Douglas informs me that there are three British 
species, in which the male is black or marked with black 
bands, whilst the females are pale-coloured or obscure. 

Order, Orthoptera. — The males in the three salta- 
torial families belonging to this Order are remark- 
able for their musical powers, namely the Achetidse or 
crickets, the Locustidae for which there is no exact 
equivalent name in English, and the Acridiidge or grass- 
hoppers. The stridulation produced by some of the 
Locustidae is so loud that it can be heard durino- the 
night at the distance of a mile ; 25 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 ca^es. All observers agree that the sounds 
serve either to call or excite the mute females. But it 
has been noticed 26 that the male migratory locust of 
Russia (one of the Acridiidae) whilst coupled with the 
female, stridulates from anger or jealousy when ap- 
proached by another male. The house-cricket when 
surprised at night uses its voice to warn its fellows. 27 In 
North America the Katy-did (Platyphyllum concavum, 



25 L. Guikling, ' Transact. Linn. Soc' vol. xv. p. 154. 

26 Koppen, as quoted in the ' Zoological Record ' for 1867, p. 46'K 

2 7 Gilbert White, ' Nat. Hist, of Seiborne,' vol. ii. 1825, p. 262. 



Chap. X. 



ORTHOPTERA. 



353 



one of the Locustidae) is described 28 as mounting on the 
upper branches of a tree, and in the evening beginning 
" his noisy babble, while rival notes issue from the neigh- 
" bouring 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 Ache- 
tidae), says, " the male has been observed to place itself 
" in the evening at the entrance of its' burrow, and 
" stridulate until a female approaches, when the louder 
" notes are succeeded by a more subdued tone, whilst 
" the successful musician caresses with his antennae 
"the mate he has won." 29 
Dr. Scudder was able to 
excite one of these insects 
to answer him, by rubbing 
on a file with a quill. 30 
In both sexes a remark- 
able auditory apparatus 
has been discovered by 
Von Siebold, situated in 
the front legs. 31 

In the three Families 

the SOUnds are differently Fig. 10. Gryllus campestris (from Landois). 

•nrnrlnnprl Tn tllP TYIfllpS of Right-band figure, under side of part of the 
prOUUCea. ±U Uie Illdieb Ul wing-nervure, much magnified, showing 




the Achetidae both wing 



the teeth, st. 
Left-band figure, upper surface of wing-cover, 
with the projecting, smooth nervure, r., 
across which the teeth (si) are scraped. 



covers have the same 
structure ; and this in the 
field-cricket (Gryllus campestris, fig. 10) consists, as de 



23 Harris, 'Insects of New England,' 1842, p. 128. 

29 « xhe 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. p. 445 and 453. 

30 'Proc. Boston Soc. of Nat. Hist.' vol. xi. April, 18G8. 

31 ' Nouveau Manuel d'Anat. Comp.' (French translat.), torn. i. 1850 
p. 567. 

VOL. I. 2 A 




354 SEXUAL SELECTION. Part II. 

scribed by Landois, 32 of from 131 to 138 sharp, trans- 
verse ridges or teeth (st) on the under side of one of the 
nervures 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 re- 
sonance. In some species the wing- 
covers of the males are furnished at 
the base with a talc-like plate. 33 I 
have here given a drawing (fig. 11) 
Fig. ii. Teeth of Nervure of the teeth on the under side of the 

of Gryllus domesticus ? ,i • j? ri 11 

(from Landois). nervure oi another species 01 Uryllus, 

viz. G. domesticus. 

In the Locustidse the opposite wing-covers differ in 
structure (fig. 12), and cannot, as in the last family, 
be indifferently used in a reversed manner. The left 
wing, which acts as the bow of the fiddle, lies over the 
right wing which serves as the fiddle itself. One of 
the nervures (a) on the under surface of the former is 
finely serrated, and is scraped across the prominent 
nervures on the upper surface of the opposite or right 
wing. In our British Pliasgonura viridissima it ap- 
peared to me that the serrated nervure is rubbed 
against the rounded hind corner of the opposite wing, 
the edge of which is thickened, coloured brown, and 
very sharp. In the right wing, but not in the left, 
there is a little plate, as transrjarent as talc, surrounded 
by nervures, and called the speculum. In Ephippig&r 
vitium, a member of this same family, we have a curious 



3: - ' Zeitsehrift fur wissenschaft. Zoolog.' B. xvii. 18G7, s. 117. 
:i3 Westwood, ' Modern Class, of Insects,' vol. i. p. 440. 



Chap. X. 



ORTHOPTERA. 



355 



subordinate modification ; for the wing-covers are greatly 
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." 34 




Fig. 12. (Jblorocoilus Tanana (from Bates), a, b. Lobes of opposite wing-covers. 

We thus see that the musical apparatus is more 
differentiated or specialised in the Locustidse, which 
includes 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. 35 
Landois, however, detected in one of the Locustidse, 
namelv in Decticus, a short and narrow row of small 



31 Westwood, ' Modern Cla&s. of Insects,' vol. i. p. 453. 
35 Landois, ibid. s. 121, 122. 

2 a 2 



356 SEXUAL SELECTION. Part II. 

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 rudi- 
mentary structure on the under side of the right wing- 
cover in Phasgonura viridissima. Hence we may with 
confidence infer that the Locustidaa are descended from 
a form, in which, as in the existing Achetidas, both 
wing-covers had serrated nervures 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 divi- 
sion of labour, the one to act exclusively as the bow and 
the other as the fiddle. 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 overlapped each other formerly as at present, and 
that the friction of the nervures produced a grating 
sound, as I find is now the case with the wing-covers 
of the females. 36 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 fitting 
variations in the roughness of the nervures having been 
continually preserved. 

In the last and third Family, namely the Acridiidae 
or grasshoppers, the stridulation is produced in a very 
difYerent manner, and is not so shrill, according to Dr. 
Scudder, as in the preceding Families. The inner sur- 
face of the femur (fig. 13, r) is furnished with a longi- 
tudinal row of minute, elegant, lancet-shaped, elastic 
teeth, from 85 to 93 in number ; 37 and these are scraped 



36 Mr. Walsh also informs me that he has noticed that the female of 
the Platyphyttum concavu.m, "when captured makes a feeble grating 
" noise by shuffling her wing-covers together." 

3 7 Landois, ibid. s. 113. 



Chap. X. 



ORTHOPTERA. 



357 



u 




Fig. 13. Hind-leg of Stenobothrus pratorura: 
r, the striduiating ridge ; lower figure, the 
teeth, forming the ridge, much magnified 
(from Landois). 



across the sharp, projecting nervures on the wing-covers, 

which are thus made to vibrate and resound. Harris 3 

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 de- 

" signed to receive it, 

" and then draws the lee 

a 



briskly up and down. 

He does not play both 
" fiddles together, but al- 
" ternately 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. 14), a S. African genus belonging to 
this same family, we meet with a new and remarkable 
modification : in the males a small notched ridge pro- 
jects obliquely from each side of the abdomen, against 
which the hind femora are rubbed. 39 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 profoundly modified for the sake of 
stridulation than any other orthopterous insect; for 



3S 'Insects of New England,' 1842, p. 133. 

M Westwood, ' Modern Classification,' vol. i. p. 462. 



358 



SEXUAL SELECTION. 



Part II. 



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 




Fig. 14. Pneumora (from specimens in the British Museum). Upper figure, male ; 

lower figure, female. 

There is one exception to the rule that the females 
in these three Families are destitute of an efficient 
musical apparatus ; for both sexes of Ephippiger (Lo- 
custidae) are said 40 to be thus provided. This case may 

40 Westwood, ibid. vol. i. p. 453. 



Chap. X. ORTHOPTERA. 359 

be compared with that of the reindeer, in which species 
alone both sexes possess horns. Although the female 
orthoptera are thus almost invariably mute, yet Landois 41 
found rudiments of the stridulating organs on the fe- 
mora of the female Acridiidae, and similar rudiments on the 
under surface of the wing-covers of the female Achetidae ; 
but he failed to find any rudiments in the females 
of Decticus, one of the Locustidae. In the Homoptera 
the mute females of Cicada, have the proper musical 
apparatus in an undeveloped state ; and we shall here- 
after meet in other divisions of the animal kingdom with 
innumerable instances of structures proper to the male 
being present in a rudimentary condition in the female. 
Such cases appear at first sight to indicate that both 
sexes were primordially constructed in the same manner, 
but that certain organs were subsequently lost by the 
females. It is, however, a more probable view, as pre- 
viously explained, that the organs in question were 
acquired by the males and partially transferred to the 
females. 

Landois has observed another interesting 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 in both sexes 
during the larval state. In the males, on the other 
hand, they become fully 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 produce their sounds are extremely 
diversified in the Orthoptera, and .are altogether dif- 
ferent from those employed by the Homoptera. But 
throughout the animal kingdom we incessantly find the 



41 Landois, ibid. s. 115, 116, 120, 122. 



360 SEXUAL SELECTION. Part II. 

same object gained by the most diversified means; this 
being due to the whole organisation undergoing in 
the course of ages multifarious changes ; and as part 
after part varies, different variations are taken advantage 
of for the same general purpose. The diversification of 
the 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. Scudder's remarkable discovery, 42 
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." This insect, though in most 
respects related to the Neuroptera, appears to connect, 
as is so often the case with very ancient forms, the 
two Orders of the Neuroptera and Orthoptera which are 
now generally ranked as quite distinct. 

I have but little more to say on the Orthoptera. 
Some of the species are very pugnacious : when two 
male field-crickets (GryJIus camjiestris) are confined 
together, they fight till one kills the other ; and the 
sj)ecies of Mantis are described as manoeuvring 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. 43 With respect 
to colour, some exotic locusts are beautifully orna- 
mented ; the posterior wings being marked with red, 



42 ' Transact. Ent. Soc' 3rd series, vol. ii. (' Journal of Proceedings, 
p. 117.) 

43 Wefctwood, 'Modern Class, of Insects,' vol. i. p. 427; for crickets, 
p. 445. 



Chap. X. NEUROPTERA. 361 

blue, and black; but as throughout the Order the 
two sexes rarely differ much in colour, it is doubtful 
whether they owe these bright tints to sexual selection. 
Conspicuous colours may be of use to these insects 
as a protection, on the principle to be explained in the 
next chapter, by giving notice to their enemies that 
they are unpalatable. Thus it has been observed 44 
that an Indian brightly-coloured locust was invariably 
rejected when offered to birds and lizards. Some cases, 
however, of sexual differences in colour in this Order 
are known. The male of an American cricket 45 is de- 
scribed 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 Phasinidae) " is of a shining 
" brownish-yellow colour; 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 46 is furnished with 
" a long membranous appendage, which falls over the 
" face like a veil ; " but whether this serves as an orna- 
ment is not known. 

Order, Neuroptera. — Little need here be said, except 
in regard to colour. In the Ephenieridae the sexes 
often differ slightly in their obscure tints; 47 but it is 
not probable that the males are thus rendered attrac- 
tive to the females. The Libellulidae or dragon-flies 
are ornamented with splendid green, blue, yellow, and 



44 Mr. Ch. Home, in < Proc. Ent. Soc' May ^3, 1869, p. xii. 

45 The Oecanthus nivalis. Harris, 'Insects of New EDgland,' 1842, 
p. 124. 

46 Platybknmus : Westwood, ' Modern. Class.' vol. i. p. 447. 

4 ? B. D. Walsh, the Pseudo-neuroptera of Illinois, in 'Proc. Ent. Soc. 
of Philadelphia,' 1802, p. 3G1. 



362 SEXUAL SELECTION. Part II. 

vermilion metallic tints; and the sexes often differ. 
Thus, the males of some of the Agrionidse, as Prof. 
Westwood remarks, 48 "are of a rich blue with black 
" wings, whilst the females are fine green with colourless 
"wings." But in Agrion Ramburii these colours are 
exactly reversed in the two sexes. 49 In the extensive 
N. American genus of Hetaerina, 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 ultra-marine blue, and in the female grass- 
green. In the allied genus Gomphus, on the other 
hand, and in some other genera, the sexes differ but 
little in colour. Throughout the animal kingdom, 
similar cases of the sexes of closely-allied forms either 
differing greatly, or very little, or not at all, are of 
frequent occurrence. Although with many Libellulidae 
there is so wide a difference in colour between the sexes, 
it is often difficult to say which is the most brilliant ; 
and the ordinary coloration of the two sexes is exactly 
reversed, as we have just seen, in one species of Agrion. 
It is not probable that their colours in any case have 
been gained as a protection. As Mr. MacLachlan, who 
has closely attended to this family, writes to me, dragon- 
flies — the tyrants of the insect-world — are the least 
liable of any insect to be attacked by birds or other 
enemies. He believes that their bright colours serve 
as a sexual attraction. It deserves notice, as bearing 
on this subject, that certain dragon-flies appear to be 
attracted by particular colours : Mr. Patterson observed 50 
that the species of Agrionidse, of which the males are 
blue, settled in numbers on the blue float of a fishing 



48 ' Modern Class.' vol. ii. p. 37. 

49 Walsh, ibid. p. 381. I am indebted to this naturalist for the 
following facts on Hetsorina, Anax, and Gomphus. 

50 ' Transact. Ent. Soc' vol. i. 1836, p. lxxxi. 



Chap. X. NEUEOPTEKA. 363 

line ; whilst two other species were attracted by shining 
white colours. 

It is an interesting fact, first observed by Schelver, 
that the males, in several genera belonging to two sub- 
families, when they first emerge from the pupal state 
are coloured exactly like the females ; but that their 
bodies in a short time assume a conspicuous 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 colour 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 51 a curious case of dimorphism, some of the 
females having their wings netted in the usual manner ; 
whilst other females 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 netting of the veins is a 
" secondary sexual character in the males." This 
latter character is generally developed in the males 
alone, but being, like every other masculine character, 
latent in the female, is occasionally developed in them. 
We have here an illustration of the manner in which 
the two sexes of many animals have probably come to 
resemble each other, namely by variations first appear- 
ing in the males, being preserved in them, and then 
transmitted to and developed in the females ; but in 
this particular genus a complete transference is occa- 
sionally and abruptly effected. Mr. MacLachlan in- 
forms me of another case of dimorphism occurring in 
several species of Agrion in which a certain number of 
individuals are found of an orange colour, and these are 



51 See abstract in the 'Zoological Record ' fur 18G7, p. 4^0. 



364 SEXUAL SELECTION. Part II. 

invariably females. This is probably a case of reversion, 
for in the true Libellulae, when the sexes differ in 
colour, the females are always orange or yellow, so 
that supposing Agrion to be descended from some pri- 
mordial form having the characteristic sexual colours 
of the typical Libellulre, it would not be surprising that 
a tendency to vary in this manner should occur in the 
females alone. 

Although many dragon-flies are such large, powerful, 
and fierce insects, the males have not been observed 
by Mr. MacLachlan to fight together, except, as he 
believes, in the case of some of the smaller species of 
Agrion. In another very distinct group in this Order, 
namely in the Termites or white auts, both sexes at 
the time of swarming may be seen running about, " the 
" male after the female, sometimes two chasing one 
t( female, and contending with great eagerness who shall 
" win the prize." 52 

Order, Hymenoptera. — That inimitable observer, M. 
Fabre, 53 in describing the habits of Cerceris, a wasp- 
like insect, remarks that " fights frequently eusue 
" between the males for the possession of some parti* 
" cular female, who sits an apparently unconcerned 
** beholder of the struggle for supremacy, and when the 
" victory is decided, quietly flies away in company 
" with the conqueror." Westwood M says that the 
males of one of the saw-flies (Tenthredinse) " have been 
" found fighting together, with their mandibles locked." 
As M. Fabre speaks of the males of Cerceris striving 
to obtain a particular female, it may be well to bear in 



52 Kirby and Spence, ' Introduct. to Entomology,' vol. ii. 1818, p. 35. 

53 See an interesting article, " The Writings of Fabre," in ' Nat. Hist. 
Review,' April, 1802, p. 122. 

54 'Journal of Proe. of Entomolcg. Soc.' Sept. 7th, 18G3, p. 169. 



Chap. X. HYMENOPTERA. 365 

mind that insects belonging to this Order have the 
power of recognising each other after long intervals of 
time, and are deeply attached. For instance, Pierre 
Huber, whose accuracy no one doubts, separated some 
ants, and when after an interval of four months they 
met others which had formerly belonged to the same 
community, they mutually recognised and caressed each 
other with their antennae. Had they been strangers 
they would have fought together. Again, when two 
communities engage in a battle, the ants on the same 
side in the general confusion sometimes attack each 
other, but they soon perceive their mistake, and the 
one ant soothes the other. 55 

In this Order slight differences in colour, according 
to sex, are common, but conspicuous differences are 
rare except in the family of Bees; yet both sexes of 
certain groups are so brilliantly coloured — for instance 
in Chrysis, in which vermilion and metallic greens 
prevail — that we are tempted to attribute the result 
to sexual selection. In the Ichneumonidaa, according to 
Mr. Walsh, 56 the males are almost universally lighter 
coloured than the females. On the other hand, in the 
Tenthredinidse the males are generally darker than the 
females. In the Siricidse the sexes frequently differ; 
thus the male of Sirex juvencus is banded with orange, 
whilst the female is dark purple ; but it is difficult to 
say which sex is the most ornamented. In Tremex 
columbte the female is much brighter coloured than the 
male. With ants, as I am informed by Mr. F. Smith, 
the males of several species are black, the females 
being testaceous. In the family Of Bees, especially in 



55 P. Huber, ' Recherches sur les Moeurs des Fourmis,' 1810, p. 150, 
165. 

56 ' Pi-oc. Eutomolog. Soc. of Philadelphia,' I860, p. 238-239. 



366 SEXUAL SELECTION". Part II. 

the solitary species, as I hear frorn the same distin- 
guished entomologist, the sexes often differ in colour. 
The males are generally the brightest, and in Bombus 
as well as in Apathus, much more variable in colour 
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. In an Australian bee 
(Lestis bombylans), the female is of an extremely brilliant 
steel-blue, sometimes tinted with vivid green ; the male 
being of a bright brassy colour clothed with rich fulvous 
pubescence. As in this group the females are provided 
with excellent defensive weapons in their stings, it is 
not probable that they have come to differ in colour 
from the males for the sake of protection. 

Mutilla Europsea emits a stridulating noise; and ac- 
cording to Groureau 57 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 concentric ridges, 
but so is the projecting thoracic collar, on 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, as do some dipterous insects ; but I have 
not referred to these sounds, as they are not known to 
be in any way connected with the act of courtship. 

Order, Coleoptera (Beetles). — Many beetles are 
coloured so as to resemble the surfaces which thev 



57 Quoted by Westwood, 'Modern Class, of Insects,' vol. ii. p. 214. 



Chap. X. COLEOPTERA. 367 

habitually frequent. Other species are ornamented 
with gorgeous metallic tints, — for instance, many Cara- 
bidae, which live on the ground and have the power 
of defending themselves by an intensely acrid secretion, 
— the splendid diamond-beetles which are protected by 
an extremely hard covering, — many species of Chry- 
somela, such as C. cerealis, a large species beautifully 
striped with various colours, and in Britain confined 
to the bare summit of Snowdon, — and a host of other 
species. These splendid colours, which are often 
arranged in stripes, spots, crosses and other elegant 
patterns, can hardly be beneficial, as a protection, except 
in the case of some flower-feeding species; and we 
cannot believe that they are purposeless. Hence the 
suspicion arises, that they serve as a sexual attraction ; 
but we have no evidence on this head, for the sexes 
rarely differ in colour. Blind beetles, which cannot of 
course behold each other's beauty, never exhibit, as I 
hear from Mr. Waterhouse, jun., bright colours, though 
they often have polished coats : but the explanation of 
their obscurity may be that blind insects inhabit caves 
and other obscure stations. 

Some Longicorns, however, especially certain Pri- 
onidte, offer an exception to the common rule that the 
sexes of beetles do not differ in colour. Most of these 
insects are large and splendidly coloured. The males in 
the genus Pyrodes, 58 as I saw in Mr. Bates' collection, are 



53 Pyrodes pulcherriinus, 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 difference 
in colour between the sexes of beetles. Kirby and Spence (' Introduct. 
to Entomology,' vol. iii. p. 301) mention a Cantharis, Meloe, Rhagium, 
and the Leptura testacca ; the male of the latter being testaceous, with 
a black thorax, and the female of a dull red all over. These two 
latter beetles belong to the Order of Longicorns. Messrs. R. Trimen 
and Waterhouse, junr., inform me of two Lamellicorns, viz., a Peri- 






368 



SEXUAL SELECTION. 



Part II. 



generally redder but rather duller than the females, the 
latter being coloured 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 colour that they have been ranked as distinct 
species : in one species both are of a beautiful shining 
green, but the male has a red thorax. On the whole, 
as far as I could judge, the females of those Prionidse, 
in which the sexes differ, are coloured more richly 
than the males; and this does not accord with the 
common rule in regard to colour when acquired through 
sexual selection. 




Fig. 10. Chalco^oma atlas. Upper figure, male (reduced) ; lower figure, female 

(nat. size). 



tricliia and Trichius, the male of the latter being more obscurely 
coloured than the female. In Tillus elongatus the male is black, and 
the female always, as it is believed, of a dark blue colour with a red 
thorax. The male, also, of Orsodacna atra, as I hear from Mr. Walsh, 
is black, the female (the so-called 0. ruficollis) having a rufous thorax. 



Chap. X. 



COLEOPTERA. 



369 




Copris isidis. (Left-hand figures, males.) 





Phanseus faun us. 




Fig. 18. 



Dipolicus canton, 





Fig. 19. 
VOL, I. 



Onthopliagus rangifer, enlarged. 



2 B 



370 SEXUAL SELECTION. Part II. 

A most remarkable distinction between the sexes of 
many beetles is presented by the great horns which 
rise from the head, thorax, or clypeus of the males ; 
and in some few cases from the under surface of the 
body. These horns, in the great family of the Lamelli- 
corns, resemble those of various quadrupeds, such 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 remarkable forms. (Figs. 15 to 1 9.) 
The females generally exhibit rudiments of the horns 
in the form of small knobs or ridges; but some are 
destitute of even a rudiment. On the other hand, the 
horns are nearly as well developed in the female as in 
the male of Phanseus Jancifer ; and only a little less 
well developed in the females of some other species of 
the same genus and of Copris. In the several sub- 
divisions of the family, the differences in structure of 
the horns do not run parallel, as I am informed by 
Mr. Bates, with their more important and characteristic 
differences ; thus within the same natural section of the 
genus Onthophagus, there are species which have either 
a single cephalic horn, or two distinct horns. 

In almost all cases, the horns are remarkable from 
their excessive variability; so that a graduated series 
can be formed, from the most highly developed males 
to others so degenerate that they can barely be distin- 
guished from the females. Mr Walsh 59 found that in 
Phaneeus camifex the horns were thrice as long in some 
males as in others. Mr. Bates, after examining above 
a hundred males of Onthophagus rangifer (fig. 19), 
thought that he had at last discovered a species in 



39 'Proc. Entomolog. Soc. of Philadelphia,' 1864, p. 228. 



Chap. X. COLEOPTERA. 371 

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 important 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 suppose r, ° that as the males wander much more 
than the females, they require horns as a defence 
against their enemies; but in many cases the horns 
do not seem well adapted for defence, as they are not 
sharp. The most obvious conjecture is that they are 
used by the males for fighting together ; but they 
have never been observed to fight ; nor could Mr. Bates, 
after a careful examination of numerous species, find 
any sufficient evidence in their mutilated or broken 
condition of their having been thus used. If the males 
had been habitual fighters, their size would probably 
have been increased through sexual selection, so as to 
have exceeded that of the female ; but Mr. Bates, after 
comparing the two sexes in above a hundred species of 
the Copridse, does not find in well-developed individuals 
any marked difference in this respect. There is, more- 
over, one beetle, belonging to the same great division 
of the Lamellicorns, namely Lethrus, the males of which 
are known to fight, but they are not provided with 
horns, though their mandibles are much larger than 
those of the female. 

The conclusion, which best agrees with the fact of 
the horns having been so immensely yet not fixedly 
developed, — as shewn by their extreme variability in 



60 Kirby and Spence, ' Introduct. Entomolog.' vol. iii. p. 300. 

2 b 2 



372 



SEXUAL SELECTION. 



Part II. 



the same species and by their extreme diversity in 
closely-allied species — is that they have been acquired 
as ornaments. This view will at first appear extremely 
improbable; but we shall hereafter find with many 
animals, standing 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. 20) are furnished 
with singular projections on their anterior femora, and 

with a great fork or pair of horns on 
the lower surface of the thorax. This 
situation seems extremely ill adapted 
for the display of these projections, 
and they may be of some real ser- 
vice ; but no use can at present be 
assigned to them. It is a highly 
remarkable fact, that although the 
Fig. 2o. onitis furcifer male, mal eg do t ^^bit even a trace of 

viewed from beneath. 

horns on the upper surface of the 
body, yet in the females a rudiment of a single horn on 
the head (fig. 21, a), and of a crest (6) on the thorax, 
are plainly visible. That the slight thoracic crest in the 






& 



Fig. 21. Left-hand figure, male of Onitis furcifer, viewed laterally. Pdght-hand figure, 
female. a. Rudiment of cephalic horn. b. Trace of thoracic horn or crest. 



female is a rudiment of a projection proper to the male, 
though entirely absent in the male of this particular 
species, is clear : for the female of Bubas bison (a form 



Chap. X. COLEOPTEEA. 373 

which comes next to Onitis) has a similar slight crest 
on the thorax, and the male has in the same situation a 
great projection. So again there can be no doubt that 
the little point (a) on the head of the female Onitis 
furcifer, as well 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 lamel- 
licorn beetles, as in Phaneeus, fig. 17. The males indeed 
of some unnamed beetles in the British Museum, which 
are believed actually to belong to the genus Onitis, are 
furnished with a similar horn. The remarkable nature 
of this case will be best perceived by an illustration : 
the Ruminant quadrupeds run parallel with the laniel- 
licorn beetles, in some females possessing horns as large 
as those of the male, in others having them much 
smaller, or existing as mere rudiments (though this is 
as rare with ruminants as it is common w r ith Lamelli- 
corns), or in having none at all. Now if a new species 
of deer or sheep were discovered with the female 
bearing distinct rudiments of horns, whilst the head 
of the male was absolutely smooth, we should have a 
case like that of Onitis furcifer. 

In this case the old belief of rudiments having been 
created to complete the scheme of nature is so far from 
holding good, that all ordinary rules are completely 
broken through. The view which seems the most pro- 
bable is that some early progenitor of Onitis acquired, 
like other Lamellicorns, horns on the head and thorax, 
and then transferred them, in a rudimentary condition, 
as with so many existing species, to the female, by whom 
they have ever since been retained. The subsequent 
loss of the horns by the male may have resulted through 
the principle of compensation from the development of 
the projections on the lower surface, whilst the female 
has not been thus affected, as she is not furnished with 



374 SEXUAL SELECTION. Part II. 

these projections, and consequently has retained the 
rudiments of the horns on the upper surface. Although 
this view is supported by the case of Bleclius imme- 
diately to be given, yet the projections on the lower 
surface differ greatly in structure and development in 
the males of the several species of Onitis, and are even 
rudimentary in some ; nevertheless the upper surface 
in all these species is quite destitute of horns. As 
secondary sexual characters are so eminently variable, it 
is possible that the projections on the lower surface may 
have been first acquired by some progenitor of Onitis and 
produced their effect through compensation, and then 
have been in certain cases almost completely lost. 

All the cases hitherto given refer to the Lam ell i- 
corns, but the males of some few other beetles, be- 
longing to two widely distinct groups, namely, the 
Curculioniclse and Staphylinidse, are furnished with 
horns, — in the former on the lower surface of the body, 61 
in the latter on the upper surface of the head and 
thorax. In the Staphylinidse the horns of the males 
in the same species are extraordinarily variable, just 
as we have seen with the Lamellicorns. In Siagonium 





9 

£}-, o v -v s ■ t 

Fig. 22. Bledius taurus, magnified. Left-hand figure, male; right-hand figure, female. 

we have a case of dimorphism, for the males can be 
divided into two sets, differing greatly in the size of 
their bodies, and in the development of their horns, 
without any intermediate gradations. In a species of 
Bledius (fig. 22), also belonging to the Staphylinidse, 
male specimens can be found in the same locality, as 



61 Kirby and Spence, ibid. vol. iii. p. 329. 



Chap. X. COLEOPTERA. 375 

Professor Westwood states, " in which the central horn 
'* of the thorax is very largp, but the horns of the head 
" quite rudimental ; and others, in which the thoracic 
" horn is much shorter, whilst the protuberances on 
" the head are long." 62 Here, then, we apparently 
have an instance of compensation of growth, which 
throws light on the curious case just given of the loss of 
the upper horns by the males of Onitis furcifer. 

Law of Battle. — Some male beetles, which seem ill 
fitted for fighting, nevertheless engage in conflicts for 
the possession of the females. Mr. Wallace 63 saw two 
males of Leptorliynchus angustatus, 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, 
" apparently in the greatest rage." The smaller male, 
however, " soon ran away, acknowledging himself van- 
" quished." In some few cases the males are well 
adapted for fighting, by possessing great toothed man- 
dibles, much larger than those of the females. 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 period 
they engage in fierce conflicts. When Mr. A. H. 
Davis 64 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 



02 ' Modern Classification of Insects,' vol. i. p. 172. On the same 
page there is an account of Siagouium. In the British Museum I 
noticed one male specimen of Siagonium in an intermediate condition, 
so that the dimorphism is not strict. 

63 ' The Malay Archipelago,' vol. ii. 1869, p. 27G. 

64 ' Entomological Magazine,' vol. i. 1833, p. 82. See also on the 
conflicts of tliis species, Kirby and Spence, ibid. vol. iii. p. 311; and 
Westwood, ibid. vol. i. p. 187. 



376 SEXUAL SELECTIOX. Part II. 

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 is well known to be the 
case with the higher animals. The males would seize 
hold of his finger, if held in front, but not so the females. 
With many of the Lucanidse, as well as with the abo^e- 
mentioned Leptorhynchus, the males are larger and 
more powerful insects than the females. The two sexes 
of Lethrus cejplialotes (one of the Lamellicorns) inhabit the 
same burrow ; and the male has larger mandibles than 
the female. If, during the breeding-season, a strenge 
male attempts to enter the burrow, 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. The action does not 
cease until the aggressor is killed or runs away. 65 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 
balls 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 66 believes, would remain on the spot until 
she died. 

The great mandibles of the male Lucanidse are ex- 
tremely variable both in size and structure, and in this 
respect resemble the horns or the head and thorax 
of many male Lamellicorns and Staphylinidse. A per- 
fect series can be formed from the best-provided to the 
worst-provided or degenerate males. Although the 
mandibles of the common stag-beetle, and probably of 



65 Quoted from Fischer, in ' Diet. Class. d'Hist. Nat.' torn. s. p. 324. 

66 'Ann. Soe. Entomolog. France,' 1866, as quoted in 'Journal of 
Travel,' by A. Murray, 186S, p. 135. 



Chap. X. 



COLEOPTERA. 



377 



many other species, are used as efficient weapons for 
fighting, it is doubtful whether their great size can 
thus be accounted for. We have 
seen that with the Lueanus ela- 
plms of N. America they are used 
for seizing the female, As they 
are so conspicuous and so ele- 
gantly branched, the suspicion 
has sometimes crossed my mind 
that they may be serviceable to 
the males as an ornament, in the 
same manner as the horns on the 
head and thorax of the various 
above described species. The 
male Chiasoc/nathus grantii of S. 
Chile — a splendid beetle belong- 
ing to the same family — has enor- 
mously-developed mandibles (fig. 
23) ; he is bold and pugnacious ; 
when threatened on any side he 
faces round, opening his great 
jaws, and at the same time stridu- 
lating loudly ; but the mandibles 
were not strong enough to pinch 
my finger so as to cause actual 
pain. 

Sexual selection, which implies 
the possession of considerable per- 
ceptive powers and of strong pas- 
sions, seems to have been more 
effective with the Lamellicorns 
than with any other family of the 
Ooleoptera or beetles. With some 
species the males are provided with weapons for fight- 
ing ; some live in pairs and show mutual affection ; 




Fig. 23. Chiasopnathus grantii, 
reduced. Upper figure, male ; 
lower figure, female. 



378 SEXUAL SELECTION. Part II. 

many have the power of stridulating when excited ; many 
are furnished with the most extraordinary horns, appa- 
rently for the sake of ornament ; some which are diurnal 
in their habits are gorgeously coloured ; and, lastly, 
several of the largest beetles in the world belong to this 
family, which was placed by Linnaeus and Fabricius at 
the head of the Order of the Coleoptera. 67 

Stridulating organs. — Beetles belonging to many 
and widely distinct families possess these organs. The 
sound can sometimes be heard at the distance of several 
feet or even yards, 68 but is not comparable with that 
produced by the Orthoptera. The part which may be 
called the rasp generally consists of a narrow slightly- 
raised surface, crossed by very fine, parallel ribs, some- 
times so fine as to cause iridescent colours, and having 
a very elegant appearance under the microscope. In 
some cases, for instance, with Typhoeus, it could be 
plainly seen that extremely minute, bristly, scale-like 
prominences, which cover the whole surrounding sur- 
face in approximately parallel lines, give rise to the 
ribs of the rasp by becoming confluent and straight, and 
at the same time more prominent and smooth. A hard 
ridge on any adjoining part of the body, which in some 
cases is specially modified for the purpose, serves as the 
scraper for the rasp. The scraper is rapidly moved across 
the rasp, or conversely the rasp across the scraper. 

These organs are situated in widely different posi- 
tions. In the carrion-beetles (Necrophorus) two parallel 
rasps (r, fig. 24) stand on the dorsal surface of the fifth 
abdominal segment, each rasp being crossed, as described 
by Landois, 69 by from 126 to 140 fine ribs. These 



6 ' Westwood, ' Modern Class.' vol. i. p. 184. 

68 Wollaston, On certain musical Curculioiiidse, 'Annals and Mag. of 
Nat. Hist.' vol. vi. 1860, p. 14. 

,;, J ' Zeitschrift fur wiss~ Zoolog.' B. xvii. 1867, s. 127. 



Chap. X. 



COLEOPTERA. 






9 



ribs are scraped by the posterior margins of the elytra, a 
small portion of which projects beyond the general out- 
line. In many Crioceridse, and in Chjthra ^-punctata 





Fig. 21. Necrophorus (from Landois). r. The two rasps. 

the rasp highly magnified. 



Left-hand figure, part of 



(one of the Chrysoinelidoe), and in some Tenebrionidae, 
&c., 70 the rasp is seated on the dorsal apex of the abdo- 
men, on the pygidium or pro-pygidium, and is scraped 
as above by the elytra. In Heterocerus, which belongs 
to another family, the rasps are placed on the sides of 
the first abdominal segment, and are scraped by ridges 
on the femora. 71 In certain Curculionidae and Cara- 
bidae, 7 ^ the parts are completely reversed in position, 



70 I am greatly indebted to Mr. G. E. Crotch for having sent me 
numerous prepared specimens of various beetles belonging to these three 
families and others, as well as for valuable information of all kinds. He 
believes 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. F. Darwin, 
finds that Dermestes murium 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. 

71 Schiodte, translated in ' Annals and Mag. of Nat. Hist.' vol. xx. 
1867, p. 37. 

72 Westring has described (Kroyer, ' Naturhist. Tidskrift,' B. ii. 184S- 
49, p. 334) the stridulating organs in these two, as well as in other 
families. In the Carabidse I have examined EldpTirus uliginosus and 
Blethisa multipunctata, sent to me by Mr. Crotch. In Blethisa the 
transverse ridges on the farrowed border of the abdominal segment do 
not come into play, as far as I could judge, in scraping the rasps on the 
elytra. 



380 



SEXUAL SELECTION. 



Part II. 



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 Pelobius hermanni (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 scraping the extreme horny margin 
of the abdomen against the rasp. In a great number 
of long-horned beetles (Longicornia) the organs are alto- 
gether differently situated, the rasp being on the meso- 
thorax, which is rubbed against the pro-thorax ; Landois 
counted 238 very fine ribs on the rasp of Ceramlyx 
hews. 

Many Lamellicorns have the power of stridulating, 
and the organs differ greatly in position. Some species 
r stridulate very loudly, so that when 

Mr. F. Smith caught a Trox sabu- 
losus, a gamekeeper who stood by 
thought that he had caught a 
mouse ; but I failed to discover the 
proper organs in this beetle. In 
Geotrupes and Typhaeus a narrow 
ridge runs obliquely across (r, fig. 
25) the coxa of each hind-leg, 
having in Gr. stercorarius 84 ribs, 
which are scraped by a specially- 
projecting part of one of the abdo- 

Fig. 25. Hind-leg of Geotrupes . , T , , 

stercorarius (from Landois). niinal segments. In the nearly 

allied Copris lunar is, 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 




8 



Easp. c Coxa, /. Femur. 
t. Tibia, tr. Tarsi. 



Chap. X. COLEOPTERA. 381 

the rasp is seated, according to Leconte, 73 on the dorsal 
surface of the abdomen. In Oryctes it is seated on the 
pro-pygidium, and in some other Dynastini, according to 
the same entomologist, on the under surface of the 
elytra. Lastly, Westring states that in Omctloplia hrun- 
nea the rasp is placed on the pro-sternum, and the scraper 
on the meta-sternum, the parts thus occupying the under 
surface of the body, instead of the upper surface as in 
the Lonsncorns. 

We thus see that the stridulatinsr organs in the dif- 
ferent coleopterous families are wonderfully diversified 
in position, but not much in structure. Within the 
same family some species are provided with these 
organs, and some are quite destitute of them. This 
diversity is intelligible, if we suppose that originally 
various species made a shuffling or hissing noise by the 
rubbing together of the hard and rough parts of their 
bodies which were in contact ; and that from the noise 
thus produced being in some way useful, the rough 
surfaces were gradually developed into regular stri- 
dulating organs. Some beetles as they move, now 
produce, either intentionally or unintentionally, a shuf- 
fling noise, without possessing any proper organs for the 
purpose. Mr. Wallace informs me that the Euchirus 
longimanus (a Lamellicorn, with the anterior legs won- 
derfully 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 hissing sound is clearly 
due to a narrow rasp running along "the sutural margin 
of each elytron ; and I could likewise make the grating 



73 I am indebted to Mr. Walsh, of Illinois, for having sent me 
extracts from Leconte's 'Introduction to Entomology,' p. 101, 143. 



382 SEXUAL SELECTION. Part II. 

sound bv rubbing the sliasrreened 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 in his two papers 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 that the stridulating organs in the 
Coleoptera differed according 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 numerous specimens which 
he had the kindness to send me for examination. Any 
slight sexual difference, however, would be difficult to 
detect, on account of the great variability of these organs. 
Thus in the first pair of the Necrojohorus humator and of 
the Pelobius which I examined, the rasp was consider- 
ably larger in the male than in the female ; but not so 
with succeeding specimens. In Geotrujoes stercorarius 
the rasp appeared to me thicker, opaquer, and more 
prominent in three males than in the same number of 
females ; consequently my son, Mr. F. Darwin, in order 
to discover whether the sexes differed in their power of 
stridulating, collected 57 liviug specimens, which he 
separated into two lots, according as they made, when 
held in the same manner, a greater or lesser noise. He 
then examined their sexes, but found that the males 
were very nearly in the same proportion to the females 
in both lots. Mr. F. Smith has kept alive numerous 
specimens of Mononychus pseudacori (Curculionidae), and 
is satisfied that both sexes stridulate, and apparently in 
an equal degree. 

Nevertheless the power of stridulating is certainly a 



Chap. X. COLEOPTERA. 383 

sexual character in some few Coleoptera. Mr. Crotch 
has discovered that the males alone of two species of 
Heliopathes (Tenebrionidse) possess striclulating organs. 
I examined five males of H. gibhus, 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 desti- 
tute of this organ ; but in addition the male 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 re- 
sembling 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 structure. 

Again, in three species of the Lamellicorn genus 
Oryctes, we have a nearly parallel case. In the females 
of 0. gryplius and nasicornis the ribs on the rasp of the 
pro-pygidium are less continuous and less distinct than 
in the males ; but the chief difference is that the whole 
upper surface of this segment, when held in the proper 
light, is seen to be clothed with hairs, which are absent 
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 0. senegal- 
ensis the difference between the sexes is more strongly 
marked, and this is best seen when the proper segment 
is cleaned and viewed as a transparent object. In the 
female the whole surface is covered with little separate 
crests, bearing spines ; whilst in the male these crests 



384 SEXUAL SELECTION. Part II. 

become, in proceeding towards the apex, 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, when 
the abdomen of a softened specimen is pushed back- 
wards and forwards, a slight grating or stridulating 
sound can be produced. 

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. This view is not rendered improbable from beetles 
stridulating under various emotions ; we know that birds 
use their voices for many purposes besides singing to 
their mates. The great Chiasognathus stridulates in 
anger or defiance ; many species do the same from dis- 
tress or fear, when held so that they cannot escape ; 
Messrs. Wollaston and Crotch were able, bv striking 
the hollow stems of trees in the Canary Islands, to dis- 
cover 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. 74 Some natu- 
ralists believe that beetles make this noise to frighten 
away their enemies ; but I cannot think that the quadru- 
peds and birds which are able to devour the larger 
beetles with their extremely hard coats, would be fright- 
ened by so slight a grating sound. The belief that 
the stridulation serves as a sexual call is supported 
by the fact that death-ticks (Anobium tessellation) are 
well known to answer each other's ticking, or, as I have 



7* M. P. de la Brulerie, as quoted in 'Journal of Travel,' A. Murray, 
vol. i. 1868, p. 135. 



Chap. X. COLEOPTEEA. 385 

myself observed, a tapping noise artificially made ; and 
Mr. Doubelday informs me that lie has twice or thrice 
observed a female ticking, 75 and in the course of an hour 
or two has found her united with a male, and on one 
occasion surrounded by several males. Finally, it seems 
probable that the two sexes of many kinds of beetles 
were at first enabled to find each other by the slight 
shuffling noise produced by the rubbing together of the 
adjoining parts of their hard bodies ; and that as the 
males or females which made the greatest noise suc- 
ceeded best in finding partners, the rugosities on various 
parts of their bodies were gradually developed by means 
of sexual selection into true stridulating organs. 



" 5 Mr. Doubleday informs me that " 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 fiir wissen. Zoolog.' B. xvii. s. 131. Olivier 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." 



.. 



VOL. I. 2 c 



386 SEXUAL SELECTION. Part II. 



CHAPTEK XL 

Insects, continued. — Order Lepidoptera. 

Courtship of "butterflies — Battles — Ticking noise — Colours com- 
mon to both sexes, or more brilliant in the males — Examples — 
Not due to the direct action of the conditions of life — Colours 
adapted for protection — Colours of moths — Display — Per- 
ceptive powers of the Lepidoptera — Variability — Causes of the 
difference in colour between the males and females — Mimickry, 
female butterflies more brilliantly coloured than the males — 
Bright colours of caterpillars — Summary and concluding re- 
marks on the secondary sexual characters of insects — Birds and 
insects compared. 

In this great Order the most interesting point for us is 
the difference in colour between the sexes of the same 
species, and between the distinct species of the same 
genus. Nearly the whole of the following chapter will 
be 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 pirouet- 
ting round a female until I became tired, without seeing 
the end of the courtship. Although butterflies are such 
weak and fragile creatures, they are pugnacious, and an 
Emperor butterfly x has been captured with the tips of 
its wings broken from a conflict with another male. 
Mr. Collingwood in speaking of the frequent battles 



1 Apatura Iris : ' The Entomologist's "Weekly Intelligencer,' 1859, 
p. 139. For the Bornean Butterflies see C. Collingwood, 'Bamblea of 
a Naturalist,' 1868, p. 183. 



Chap. XL BUTTERFLIES AND MOTHS. 387 

between the butterflies of Borneo says, "They whirl 
" round each other with the greatest rapidity, and appear 
" to be incited by the greatest ferocity." One case is 
known of a butterfly, namely the Ageronia feronia, 
which makes a noise like that produced by a toothed 
wheel passing under a spring catch, and which could be 
heard at the distance of several yards. At Kio de Janeiro 
this sound was noticed by me, only when two were 
chasing each other in an irregular course, so that it is 
probably made during the courtship of the sexes ; but I 
neglected to attend to this point. 2 

Every one has admired the extreme beauty of many 
butterflies and of some moths ; and we are led to ask, 
how has this beauty been acquired ? Have their colours 
and diversified patterns simply resulted from the direct 
action of the physical conditions to which these insects 
have been exposed, without any benefit being thus de- 
rived ? Or have successive variations been accumulated 
and determined either as a protection or for some un- 
known purpose, or that one sex might be rendered 
attractive to the other ? And, again, what is the mean- 
ing of the colours being widely different in the males 
and females of certain species, and alike in the two 
sexes of other species? Before attempting to answer 
these questions a body of facts must be given. 

With most of our English butterflies, both those which 
are beautiful, such as the admiral, peacock, and painted 
lady (Vanessse), and those which are plain-coloured, 
such as the meadow-browns (Hipparchiae), the sexes 
are alike. This is also the case with the magnificent 
Heliconidse and Danaidse of the tropics. But in certain 



2 See my ' Journal of Eesearches,' 1845, p. 33. Mr. Doubleday has 
detected (' Proc. Ent. Soc.' March 3rd, 1845, p. 123) a peculiar mem- 
branous sac at the base of the front wings, which is probably con- 
nected with the production of the sound. 

2 c 2 



388 SEXUAL SELECTION. Part II. 

other tropical groups, and with some of our English 
butterflies, as the purple emperor, orange-tip, &c. (Apa- 
tura Iris and Anthocharis cardamines), the sexes differ 
either greatly or slightly in colour. No language suffices 
to describe the splendour of the males of some tropical 
species. Even within the same genus we often find spe- 
cies presenting an extraordinary difference between the 
sexes, whilst others have their sexes closely alike. Thus 
in the South American genus Epical ia, Mr. Bates, to 
whom I am much indebted for most of the following 
facts and for looking over this whole discussion, informs 
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 therefore cannot have been dif- 
ferently affected by external conditions. 3 In nine of 
these species the males rank amongst the most brilliant 
of all butterflies, and differ so greatly from the compa- 
ratively 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 likewise resemble both sexes in several allied genera, 
found in various parts of the world. Hence in accord- 
ance with the descent-theory we may infer that these 
nine species, and probably all the others of the genus, 
are descended from an ancestral form which was coloured 
in nearly the same manner. In the tenth species the 
female still retains the same general colouring, but the 
male resembles her, so that he is coloured 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 type of colouring which 



3 See also Mr. Bates' 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,' I860, p. 278. 



Chap. XL BUTTERFLIES AND MOTHS. 389 

is usual with their sex in this genus, for they are gaily 
decorated in nearly the same manner as the males, but 
in a somewhat less degree. Hence in these two species 
the bright colours of the males seem to have been trans- 
ferred to the females ; whilst the male of the tenth 
species has either retained or recovered the plain 
colours of the female as well as of the parent-form of 
the genus ; the two sexes being thus rendered in both 
cases, though in an opposite manner, nearly alike. In 
the allied genus Eubagis, both sexes of some of the 
species are plain-coloured and nearly alike ; whilst 
with the greater number the males are decorated with 
beautiful metallic tints, in a diversified manner, and 
differ much from their females. The females through- 
out the genus retain the same general style of colouring, 
so that they commonly resemble each other much more 
closely than they resemble their own proper males. 

In the genus Papilio, all the species of the iEneas 
group are remarkable for their conspicuous and strongly 
contrasted colours, and they illustrate the frequent ten- 
dency to gradation in the amount of difference between 
the sexes. In a few species, for instance in P. ascanius, 
the males and females are alike ; in others the males 
are a little or very much more superbly coloured than 
the females. The genus Junonia allied to our Vanessaa 
offers a nearly parallel case, for although the sexes of 
most of the species resemble each other and are desti- 
tute of rich colours, yet in certain species, as in J. oenone, 
the male is rather more brightly coloured 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 Theclae, in which both sexes 



390 SEXUAL SELECTION. Part II. 

are nearly alike and wonderfully splendid ; in another, 
the male is coloured in a similarly gorgeous manner, 
whilst the whole upper surface of the female is of a dull 
uniform brown. Our common little English blue butter- 
flies of the genus Lycsena, illustrate the various differ- 
ences in colour between the sexes, almost as well, 
though not in so striking a manner, as the above exotic 
genera. In Lycsena agestis both sexes have wings of a 
brown colour, bordered with small ocellated orange 
spots, and are consequently alike. In L. oegon the 
wings of the male are of a fine blue, bordered with 
black ; whilst the wings of the female are brown, with 
a similar border, and closely resemble those of L. agestis. 
Lastly, in L. avion both sexes are of a blue colour and 
nearly alike, though in the female the edges of the 
wings are rather duskier, w 7 ith the black spots plainer ; 
and in a bright blue Indian species both sexes are still 
more closely alike. 

I have given the foregoing cases in some detail in 
order to shew, in the first place, that when the sexes of 
butterflies differ, the male as a general rule is the most 
beautiful, and departs most from the usual type of colour- 
ing of the group to which the species belongs. Hence in 
most groups the females of the several species resemble 
each other much more closely than do the males. In 
some exceptional cases, however, to which I shall here- 
after allude, the females are coloured more splendidly 
than the males. In the second place these cases 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 colour to so great a dif- 
ference 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 apparently may be due either to the 



Chap. XI. BUTTERFLIES AND MOTHS. 391 

male having transferred his colours to the female, 
or to the male having retained, or perhaps reco- 
vered, the primordial colours of the genus to which the 
species belongs. It also deserves notice that in those 
groups in which the sexes present any difference of 
colour, the females usually resemble the males to a cer- 
tain extent, so that when the males are beautiful to an 
extraordinary degree, the females almost invariably ex- 
hibit some degree of beauty. From the numerous 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, whatever they may 
be, which have determined the brilliant colouring of the 
males alone of some species, and of both sexes in a more 
or less equal degree of other species, have generally 
been the same. 

As so many gorgeous butterflies inhabit the tropics, it 
has often been supposed that they owe their colours to 
the great heat and moisture of these zones ; but Mr. 
Bates 4 has shewn by the comparison of various closely- 
allied groups of insects from the temperate and tropical 
regions, that this view cannot be maintained; and the 
evidence becomes conclusive when brilliantly-coloured 
males and plain-coloured females of the same species 
inhabit the same district, feed on the same food, and 
follow exactly the same habits of life. Even when 
the sexes resemble each other, we can hardly believe 
that their brilliant and beautifully-arranged colours are 
the purposeless result of the nature of the tissues, and 
the action of the surrounding conditions. 

With animals of all kinds, whenever colour has been 
modified for some special purpose, this has been, as far 



4 ' The Naturalist on the Amazons,' vol. i. 1863, p. 19. 



392 SEXUAL SELECTION. Part II. 

as we can judge, either for protection or as an attraction 
between the sexes. With many species of butterflies 
the upper surfaces of the wings are obscurely coloured, 
and this in all probability leads to their escaping ob- 
servation and danger. But butterflies when at rest 
would be particularly liable to be attacked by their 
enemies; and almost all the kinds when resting raise 
their wings vertically over their backs, so that the lower 
sides alone are exposed to view. Hence it is this side 
which in many cases is obviously coloured so as to 
imitate the surfaces on which these insects commonly 
rest. Dr. Bossier, I believe, first noticed the similarity 
of the closed wings of certain Yanessaa and other butter- 
flies to the bark of trees. Many analogous and striking 
facts could be given. The most interesting one is that 
recorded by Mr. Wallace 5 of a common Indian and 
Sumatran butterfly (Kallima), which disappears like 
magic when it settles in a bush ; for it hides its head 
and antennae between its closed wings, and these in 
form, colour, and veining cannot be distinguished from 
a withered leaf together with the footstalk. In some 
other cases the lower surfaces of the wings are brilliantly 
coloured, and yet are protective ; thus in Theda rubi 
the wings when closed are of an emerald green and re- 
semble the young leaves of the bramble, on which this 
butterfly in the spring may often be seen seated. 

Although the obscure tints of the upper or under 
surface of many butterflies no doubt serve to conceal 
them, yet we cannot possibly extend this view to 
the brilliant and conspicuous colours of many kinds, 
such as our admiral and peacock Vanessae, our white 



5 See the interesting article in the * Westminster Eeview,' July, 1867, 
p. 10. A woodcut of the Kallima is given by Mr. Wallace in ' Hard- 
wicke's ' Science Gossip,' Sept. 1867, p. 196. 



Chap. XI. BUTTERFLIES AND MOTHS. 393 

cabbage-butterflies (Pieris), or the great swallow-tail 
Papilio which haunts the open fens — for these butter- 
flies are thus rendered visible to every living creature. 
With these species both sexes are alike ; but in the 
common brimstone butterfly (Gonepteryx rhamni), the 
male is of an intense yellow, whilst the female is much 
paler; and in the orange-tip (Anthoeharis cardamines) 
the males alone have the bright orange tips to their 
wings. In these cases the males and females are 
equally conspicuous, and it is not credible that their 
difference in colour stands in any relation to ordinary 
protection. Nevertheless it is possible that the con- 
spicuous colours of many species may be in an indirect 
manner beneficial, as will hereafter be explained, by 
leading their enemies at once to recognise them as 
unpalatable. Even in this case it does not certainly 
follow that their bright colours and beautiful patterns 
were acquired for this special purpose. In some other 
remarkable cases, beauty has been gained for the sake 
of protection, 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. 

The female of our orange-tip buttterny, above re- 
ferred to, and of an American species (Anth. genutia) 
probably shew us, as Mr. Walsh has remarked to me, 
the primordial colours of the parent - species of the 
genus ; for both sexes of four or five widely-distributed 
species are coloured in nearly the same manner. We 
may infer here, as in several previous cases, that it is 
the males of Anth. cardamines and genutia which have 
departed from the usual type of colouring of their genus. 
In the Anth. sara from California, the orange-tips have 
become partially developed in the female ; for her wings 
are tipped with reddish-orange, but paler than in the 



394 • SEXUAL SELECTION. Part II. 

male, and slightly different in some other respects. In 
an allied Indian form, the Ijjhias glauci^e, the orange- 
tips are fully developed in both sexes. In this Iphias 
the under surface of the wings marvellously resembles, 
as pointed out to me by Mr. A. Butler, a pale-coloured 
leaf; and in our English orange-tip, the under surface 
resembles the flower-head of the wild parsley, on which 
it may be seen going to rest at night. 6 The same 
reasoning power which compels us to believe that the 
lower surfaces have here been coloured for the sake of 
protection, leads us to deny that the wings have been 
tipped, especially when this character is confined to the 
males, with bright orange for the same purpose. 

Turning now to Moths : most of these rest motion- 
less with their wings depressed during the whole or 
greater part of the day ; and the upper surfaces of their 
wings are often shaded and coloured in an admirable 
manner, as Mr. Wallace has remarked, for escaping 
detection. With most of the • Boinbycidse and Noc- 
tuidse, 7 when at rest, the front-wings overlap and 
conceal the hind-wings; so that the latter might be 
brightly coloured without much risk ; and they 
are thus coloured in many species of both families. 
During the act of flight, moths w r ould often be able 
to escape from their enemies ; nevertheless, as the 
hind-wings are then fully exposed to view, their bright 
colours must generally have been acquired at the 
cost of some little risk. But the following fact shews 
us how cautious we ought to be in drawing conclu- 
sions on this head. The common yellow under-wings 



6 See the interesting observations by Mr. T. "W. Wood, ' The Stu- 
dent,' Sept. 1868, p. 81. 

7 Mr. Wallace in ' Hardwicke's Science Gossip,' Sept. 1S67, p. 193. 



Chap. XI. BUTTERFLIES AND MOTHS. 395 

(Triphaena) often fly about during the day or early 
evening, and are then conspicuous from the colour 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 coloured and 
fragile surfaces, instead of at the body. For instance, 
Mr. Weir turned into his aviary a vigorous specimen of 
Triphaena pronuba, which was instantly pursued by 
a robin ; but the bird's attention being caught by the 
coloured wings, the moth was not captured until after 
about fifty attempts, and small portions of the wings 
were repeatedly broken off. He tried the same experi- 
ment, in the open air, with a T. fimbria and swallow; 
but the large size of this moth probably interfered 
with its capture. 8 We are thus reminded of a state- 
ment made by Mr. Wallace, 9 namely, that in the Bra- 
zilian forests and Malayan islands, many common and 
highly-decorated butterflies are weak flyers, though fur- 
nished with a broad expanse of wings ; 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 in pro- 
" portion to the body, it seems probable that the insect 
" would more frequently have been struck or pierced in 
"a vital part, and thus the increased expanse of the 
" wings may have been indirectly beneficial." 

Display. — The bright colours of butterflies and of 
some moths are specially arranged^for display, whether 
or not they serve in addition as a protection. Bright 



8 See also, on this subject, Mr. Weir's paper in ' Transact. Ent. Soc' 
1869, p. 23. A/ O "os Hl 

9 ' Westminster Review,' July, 1867, p. 16. 

lL jiLIBR f 



396 SEXUAL SELECTION. Part II. 

colours would not be visible during: the nig^ht: and 
there can be no doubt that moths, taken as a body, are 
much less gaily decorated than butterflies, all of which 
are diurnal in their habits. But the moths in certain 
families, such as the Zygaenidae, various Sphingidaa, 
Uraniidae, some Arctiidse and Saturniidaa, fly about 
during the clay or early evening, and many of these 
are extremely beautiful, being far more brightly 
coloured than the strictly nocturnal kinds. A few 
exceptional cases, however, of brightly-coloured noc- 
turnal species have been recorded. 10 

There is evidence of another kind in regard to display. 
Butterflies, as before remarked, elevate their wings 
when at rest, and whilst basking in the sunshine often 
alternately raise and depress them, thus exposing to full 
view both surfaces; and although the lower surface is 
often coloured in an obscure manner as a protection, 
yet in many species it is as highly coloured as the 
upper surface, and sometimes in a very different man- 
ner. In some tropical species the lower surface is even 
more brilliantly coloured than the upper. 11 In one 
English fritillary, the Argijnnis aglaia, the lower sur- 
face alone is ornamented with shining silver discs. 
Nevertheless, as a general rule, the upper surface, 
which is probably the most fully exposed, is coloured 
more brightly and in a more diversified manner than 
the lower. Hence the lower surface generally affords 



10 For instance, Lithosia ; but Prof. Westwood (' Modern Class, of 
Insects,' vol. ii. p. 390) seems surprised at this case. On the relative 
colours of diurnal and nocturnal Lepidoptera, see ibid. p. H33 and 392 ; 
also Harris, ' Treatise on the Insects of New England,' 1842, p. 315. 

11 Such differences between the upper and lower surfaces of the 
wings of several species of Papilio, may be seen in the beautiful plates 
to Mr. Wallace's Memoir on the Papilionidse of the Malayan liegiou, 
in ' Transact. Linn. Soc' vol. xxv. part i. 1865. 



Chap. XI. BUTTERFLIES AND MOTHS. 397 

to entomologists the most useful character for detecting 
the affinities of the various species. 

Now if we turn to the enormous group of moths, 
which do not habitually expose to full view the under 
surface of their wings, this side is very rarely, as I hear 
from Mr. Stainton, coloured more brightly than the 
upper side, or even with equal brightness. Some ex- 
ceptions to the rule, either real or apparent, must be 
noticed, as that of Hypopyra, specified by Mr. Wormald. 12 
Mr. E. Trimen informs me that in Guenee's great work, 
three moths are figured, in which the under surface is 
much the most brilliant. For instance, in the Australian 
Gastrophora the upper surface of the fore-wing is pale 
greyish-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 colouring. Mr. 
Trimen also informs me that the lower surface of the 
wings in certain other Geometrse 13 and quadrifid Noctuae 
are either more variegated or more brightly-coloured 
than the upper surface ; but some 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 to view the under surface. 
Other species when settled on the ground or herbage 
have the habit of now and then suddenly and slightly 
lifting up their wings. Hence the lower surface of the 
wings being more brightly-coloured- than the upper sur- 



12 ' Proc. Eut. Soc' March 2nd, 1868. 

13 See also an account of the S. American genus Erateina (one of 
the Geometrse) in ' Transact. Ent. Soc.' new series, vol. v. pi. xv. and 
xvi. 



398 SEXUAL SELECTION. Part II. 

face in certain moths is not so anomalous a circum- 
stance as it at first appears. The Saturniidse include 
some of the most beautiful of all moths, their wings 
being decorated, as in our British Emperor moth, with 
fine ocelli ; and Mr. T. W. Wood w 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, nor as 
far as I can discover hardly any foreign species, which 
are brilliantly coloured, differ much in colour according 
to sex ; though this is the case with many brilliant but- 
terflies. The male, however, of one American moth, the 
Satumia Io, is described as having its fore-wings deep 
yellow 7 , curiously marked with purplish-red spots ; whilst 
the wings of the female are purple-brown, marked with 
grey lines, 15 The British moths which differ sexually in 
colour are all brown, or various tints of dull yellow, or 
nearly white. In several species the males are much 
darker than the females, 16 and these belong to groups 
which generally fly about during the afternoon. On the 
other hand, in many genera, as Mr. Stainton informs me, 



14 ' Proc. Ent. Soc. of London,' July 6, 1868, p. xxvii. 

15 Harris, ' Treatise/ &c, edited by Flint, 1862, p. 395. 

16 For instance, I observe in my son's cabinet that the males are 
darker than the females in the Lasiocampa quercus, Odonestis potatoria, 
Hypogymna dispar, Dasycliira pudibunda, and Cycnia mendlca. In this 
latter species the difference in colour between the two sexes is strongly 
marked ; and Mr. Wallace informs me that we here have, as he believes, 
an instance of protective mimickry 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 colour would thus be highly beneficial. 



Chap. XL BUTTERFLIES AND MOTHS. 399 

the males have the hind-wings whiter than those of 
the female — of which fact Agrotis exclamationis offers a 
good instance. The males are thus rendered more 
conspicuous than the females, whilst flying about in 
the dusk. In the Ghost Moth (Hejnalus humuli) the 
difference is more strongly marked; the males being 
white and the females yellow with darker markings. 
It is difficult to conjecture what the meaning can be 
of these differences between the sexes in the shades of 
darkness or lightness ; but we can hardly suppose that 
they are the result of mere variability with sexually- 
limited inheritance, independently of any benefit thus 
derived 

From the foregoing statements it is impossible to 
admit that the brilliant colours of butterflies and of 
some few moths, have commonly been acquired for the 
sake of protection. We have seen that their colours 
and elegant patterns are arranged and exhibited as 
if for display. Hence I am led to suppose that the 
females generally prefer, or are most excited by the 
more brilliant males ; for on any other supposition 
the males would be ornamented, as far as we can 
see, for no purpose. We know that ants and certain 
lamellicorn beetles are capable of feeling an attachment 
for each other, and that ants recognise their fellows 
after an interval of several months. Hence there is no 
abstract improbability in the Lepidoptera, which pro- 
bably stand nearly or quite as high in the scale as these 
insects, having sufficient mental capacity to admire 
bright colours. They certainly discover flowers by 
colour, and, as I have elsewhere shewn, the plants 
which are fertilised exclusively by the wind never have 
a conspicuously-coloured corolla. 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 } 



400 SEXUAL SELECTION. Part II. 

and I have been assured by a friend, that these moths 
repeatedly visited flowers painted on the walls of a room 
in the South of France. The common white butterfly, 
as I hear from Mr. Doubleday, often flies down to a bit 
of paper on the ground, no doubt mistaking it for one of 
its own species. Mr. Collingwood 17 in speaking of the 
difficulty of collecting certain butterflies 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 a prolonged affair. The 
males sometimes fight together in rivalry ; and many 
may be seen pursuing or crowding round the same 
female. If, then, the females do not prefer one male to 
another, the pairing must be left to mere chance, and 
this does not appear to me a probable event. If, on the 
other hand, the females habitually, or even occasionally, 
prefer the more beautiful males, the colours of the latter 
will have been rendered brighter by degrees, and will 
have been transmitted to both sexes or to one sex, 
according to which law of inheritance prevailed. The 
process of sexual selection will have been much facili- 
tated, if the conclusions arrived at from various kinds of 
evidence in the supplement to the ninth chapter can be 
trusted ; namely that the males of many Lepidoptera, 
at least in the imago state, greatly exceed in number 
the females. 

Some facts, however, are opposed to the belief that 
female butterflies prefer the more beautiful males ; thus, 
as I have been assured by several observers, fresh females 
may frequently be seen paired with battered, faded or 



17 ' Eambles of a Naturalist in the Chinese Seas,' 1868, p. 182. 



Chap. XL BUTTERFLIES AND MOTHS. 401 

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 Bombyeiclaa, the sexes pair imme- 
diately 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-moth (B. mori), 
as I have been told by some continental and English 
breeders. Dr. Wallace, who has had such immense 
experience in breeding Bomhtjx cynthia, is convinced 
that the females evince no choice or preference. He 
has kept above 300 of these moths living together, and 
has often found the most vigorous females mated with 
stunted males. The reverse apparently seldom occurs ; 
for, as he believes, the more vigorous males pass over the 
weakly females, being attracted by those endowed with 
most vitality. Although we have been indirectly in- 
duced to believe that the females of many species prefer 
the more beautiful males, I have no reason to suspect, 
either with moths or butterflies, that the males are 
attracted by the beauty of the females. If the more 
beautiful females had been continually preferred, it is 
almost certain, from the colours of butterflies being so 
frequently transmitted to one sex alone, that the females 
would often have been rendered more beautiful than 
their male partners. But this does not occur except in 
a few instances ; and these can be explained, as we 
shall presently see, on the principle of mimickry and 
protection. 

As sexual selection primarily depends on variability, 
a few words must be added on this subject. In respect 
vol. i. 2d 



402 SEXUAL SELECTION. Part II. 

to colour there is no difficulty, as any number of highly 
variable Lepicloptera could be named. One good in- 
stance will suffice. Mr. Bates shewed me a whole series 
of specimens of Pcqoilio sesostris and children^ ; in the 
latter the males varied much in the extent of the beau- 
tifully enamelled green patch on the fore-wings, and 
in the size of the white mark, as well as of the splendid 
crimson stripe on the hind-wings ; so that there was 
a great contrast between the most and least gaudy 
males. The male of Pajnlio sesostris, though a beautiful 
insect, is much less so than P. chilclrense. It likewise 
varies a little in the size of the green patch on the fore- 
wings, and in the occasional appearance of a 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 least bright of P. children^, 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 by means of selec- 
tion the beauty of either species. The variability is 
here almost confined to the male sex ; but Mr. Wallace 
and Mr. Bates have shewn 18 that the females of some 
other species are extremely variable, the males being 
nearly constant. As I have before mentioned the Ghost 
Moth (Hepialus humuli) as one of the best instances in 
Britain of a difference in colour between the sexes of 
moths, it may be worth adding 19 that in the Shetland 



18 Wallace on the Papilionidae of the Malayan Region, in ' Transact. 
Linn. Soc.' vol. xxv. 1865, p. 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. Entomolog. 
Soc.' Nov. 19th, 1866, p. xl. 

19 Mr. R. MacLacblan, ' Transact. Ent. Soc' vol. ii. part 6th, 3rd 
series, 1866, p. 459. 



Chap. XL BUTTERFLIES AND MOTHS. 403 

Islands, males are frequently found which closely 
resemble the females. In a future chapter I shall have 
occasion to shew that the beautiful eye-like spots or 
ocelli, so common on the wings of many Lepidoptera, 
are eminently variable. 

On the whole, although many serious objections may 
be urged, it seems probable that most of the species of 
Lepidoptera which are brilliantly coloured, owe their 
colours to sexual selection, excepting in certain cases, 
presently to be mentioned, in which conspicuous colours 
are beneficial as a protection. From the ardour 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 
here acted, the male, when the sexes differ, ought to be 
the most brilliantly coloured ; and this undoubtedly is 
the ordinary rule. When the sexes are brilliantly co- 
loured and resemble each other, the characters acquired 
by the males appear to have been transmitted to both 
sexes. But will this explanation of the similarity and 
dissimilarity in colour between the sexes suffice ? 

The males and females of the same species of butterfly 
are known 20 in several cases to inhabit different stations, 
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, 21 as in the adult 
state they are exposed during a very short period to 
different conditions ; and the larvae" of both are ex- 
posed to the same conditions. Mr. Wallace believes 



20 H. W. Bates, 'The Naturalist on the Amazons/ vol. ii. 1863, 
p. 228. A. E. Wallace, in ' Transact. Linn. Soc' vol. xxv. 1865, p. 10. 

21 On this whole subject see ' The Variation of Animals and Plants 
under Domestication,' vol. ii. 1868, chap, xxiii. 

2 d 2 



404 SEXUAL SELECTION. Part II. 

that the less brilliant colours of the female have been 
specially gained in all or almost all cases for the sake 
of protection. On the contrary it seems to me more 
probable that the males alone, in the large majority of 
cases, have acquired their bright colours through sexual 
selection, the females having been but little modified. 
Consequently the females of distinct but allied species 
ought to resemble each other much more closely than 
do the males of the same species ; and this is the general 
rule. The females thus approximately show us the pri- 
mordial colouring of the parent-species of the group to 
which they belong. They have, however, almost always 
been modified to a certain extent by some of the succes- 
sive steps of variation, through the accumulation of 
which the males were rendered beautiful, having been 
transferred to them. The males and females of allied 
though distinct species will also generally have been 
exposed during their prolonged larval state to different 
conditions, and may have been thus indirectly affected ; 
though with the males any slight change of colour thus 
caused will often have been completely masked by the 
brilliant tints gained through sexual selection. When 
we treat of Birds, I shall have to discuss the whole 
question whether the differences in colour between the 
males and females have been in part specially gained 
by the latter as a protection ; so that I will here only 
give unavoidable details. 

In all cases when the more common form of equal 
inheritance by both sexes has prevailed, the selection of 
bright-coloured males would tend to make the females 
bright-coloured ; and the selection of dull-coloured fe- 
males wmdd tend to make the males dull. If both pro- 
cesses were carried on simultaneously, they would tend 
to neutralise each other. As far as I can see, it would 
be extremely difficult to change through selection the 



Chap. XI. BUTTERFLIES AND MOTHS. 405 

one form of inheritance into the other. Bat by the 
selection of successive variations, which were from the 
first sexually limited in their transmission, there would 
not be the slightest difficulty in giving bright colours to 
the males alone, and at the same time or subsequently, 
dull colours to the females alone. In this latter manner 
female butterflies and moths may, as I fully admit, have 
been rendered inconspicuous for the sake of protection, 
and widely different from their males. 

Mr. Wallace 22 has argued with much force in favour 
of his view that when the sexes differ, the female has 
been specially modified for the sake of protection ; and 
that this has been effected by one form of inheritance, 
namely, the transmission of characters to both sexes, 
having been changed through the agency of natural 
selection into the other form, namely, transmission to 
one sex. I was at first strongly inclined to accept this 
view ; but the more I have studied the various classes 
throughout the animal kingdom, the less probable it 
has appeared. Mr. Wallace urges that both sexes of 
the Heliconidae, Danaidse, Acrseidm are equally brilliant 
because both are protected from the attacks of birds 
and other enemies, by their offensive odour ; but that 
in other groups, which do not possess this immunity, 
the females have been rendered inconspicuous, from 
having more need of protection than the males. This 
supposed difference in the " need of protection by the 
" two sexes ' is rather deceptive, and requires some 
discussion. It is obvious that brightly-coloured indi- 
viduals, whether males or females, would equally attract, 
and obscurely-coloured individuals equally escape, the 



22 A. E. Wallace, in 'The Journal of Travel,' vol. i. 1868, p. 88. 
'Westminster Keview,' July, 1867, p. 37. See also Messrs. Wallace 
and Bates in ' Proc. Ent. Soc' Nov. 19th, 1S66, p. xxxix. 



406 SEXUAL SELECTION. Part II. 

attention of their enemies. But we are concerned 
with the effects of the destruction or preservation of 
certain individuals of either sex, on the character of 
the race. With insects, after the male has fertilised 
the female, and after the latter has laid her eggs, 
the greater or less immunity from danger of either sex 
could not possibly have any effect on the offspring. 
Before the sexes have performed their proper functions, 
if they existed in equal numbers and if they strictly 
paired (all other circumstances being the same), the 
preservation of the males and females would be equally 
important for the existence of the species and for the 
character of the offspring. But with most animals, as 
is known to be the case with the domestic silk-moth, 
the male can fertilise two or three females ; so that the 
destruction of the males would not be so injurious to 
the species as that of the females. On the other hand, 
Dr. Wallace believes that with moths the progeny from 
a second or third fertilisation is apt to be weakly, and 
therefore would not have so good chance of surviving. 
When the males exist in much greater numbers than the 
females, no doubt many males might be destroyed with 
impunity to the species ; but I cannot see that the 
results of ordinary selection for the sake of protection 
would be influenced by the sexes existing in unequal 
numbers ; for the same proportion of the more con- 
spicuous individuals, whether males or females, would 
probably be destroyed. If indeed the males presented 
a greater range of variation in colour, the result would 
be different ; but we need not here follow^ out such com- 
plex details. On the whole I cannot perceive that an 
inequality in the numbers of the two sexes would in- 
fluence in any marked manner the effects of ordinary 
selection on the character of the offspring. 

Female Lepidoptera require, as Mr. Wallace insists, 



Chap. XI. BUTTEEFLIES AND MOTHS. 407 

some days to deposit tlieir fertilised ova and to search 
for a proper place; during this period (whilst the life 
of the male was of no importance) the brighter-coloured 
females would be exposed to clanger and would be 
liable to be destroyed. The duller-coloured females on 
the other hand would survive, and thus would in- 
fluence, it might be thought, in a marked manner the 
character of the species, — either of both sexes or of 
one sex, according to which form of inheritance pre- 
vailed. But it must not be forgotten that the males 
emerge from the cocoon-state some days before the 
females, and during this period, whilst the unborn 
females were safe, the brighter-coloured males would be 
exposed to danger ; so that ultimately both sexes w r ould 
probably be exposed during a nearly equal length of 
time to clanger, and the elimination of conspicuous 
colours would not be much more effective in the one 
than the other sex. 

It is a more important consideration that female 
Lepicloptera, as Mr. Wallace remarks, and as is known 
to every collector, are generally slower flyers than 
the males. Consequently the latter, if exposed to 
greater danger from being conspicuously coloured, 
might be able to escape from their enemies, whilst the 
similarly-coloured females would be destroyed ; and thus 
the females would have the most influence in modi- 
fying the colour of their progeny. 

There is one other consideration : bright colours, as 
far as sexual selection is concerned, are commonly of 
no service to the females ; so that if the latter varied 
in brightness, and the variations were sexually limited 
in their transmission, it would depend on mere chance 
whether the females had their bright colours increased ; 
and this would tend throughout the Order to diminish 
the number of species with brightly-coloured females 



408 SEXUAL SELECTION. Part II. 

in comparison with the species having brightly-coloured 
males. On the other hand, as bright colours are sup- 
posed to be highly serviceable to the males in their 
love-struggles, the brighter males (as we shall see 
in the chapter on Birds) although exposed to rather 
greater danger, would on an average procreate a greater 
number of offspring than the duller males. In this 
case, if the variations were limited in their transmission 
to the male sex, the males alone would be rendered 
more brilliantly coloured ; but if the variations were 
not thus limited, the preservation and augmentation of 
such variations would depend on whether more evil was 
caused to the species by the females being rendered 
conspicuous, than good to the males by certain indivi- 
duals being successful over their rivals. 

As there can hardly be a doubt that both sexes of 
many butterflies and moths have been rendered dull- 
coloured for the sake of protection, so it may have 
been with the females alone of some species in which 
successive variations towards dullness first appeared 
in the female sex and were from the first limited in 
their transmission to the same sex. If not thus limited, 
both sexes would become dull-coloured. We shall 
immediately see, when we treat of mimickry, that 
the females alone of certain butterflies have been ren- 
dered extremely beautiful for the sake of protection, 
without any of the successive protective variations 
having been transferred to the male, to whom they 
could not possibly have been in the least degree injuri- 
ous, and therefore could not have been eliminated 
through natural selection. Whether in each particular 
species, in which the sexes differ in colour, it is the 
female which has been specially modified for the sake 
of protection ; or whether it is the male which has been 
specially modified for the sake of sexual attraction, the 



Chap. XI. BUTTEEFLIES AND MOTHS. 409 

female having retained her primordial colouring only 
slightly changed through the agencies before alluded 
to ; or whether again both sexes have been modified, 
the female for protection and the male for sexual attrac- 
tion, can only be definitely decided when we know the 
life-history of each species. 

Without distinct evidence, I am unwilling to admit 
that a double process of selection has long been going 
on with a multitude of species, — the males having been 
rendered more brilliant by beating their rivals ; and the 
females more dull-coloured by having escaped from their 
enemies. We may take as an instance the common brim- 
stone butterfly (G-onepteryx), which appears early in the 
spring before any other kind. The male of this species 
is of a far more intense yellow than the female, though 
she is almost equally conspicuous ; and in this case 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 colours as a sexual 
attraction. The female of Anthocharis cardamines does 
not possess the beautiful orange tips to her wings with 
which the male is ornamented ; consequently she closely 
resembles the white butterflies (Pieris) so common in 
our gardens ; but we have no evidence that this resem- 
blance is beneficial. On the contrary, as she resembles 
both sexes of several species of the same genus inhabit- 
ing various quarters of the world, it is more probable 
that she has simply retained to a large extent her 
primordial colours. 

Various facts support the conclusion that with the 
greater number of brilliantly-coloured Lepidoptera, it 
is the male which has been modified ; the two sexes 
having come to differ from each other, or to resemble 
each other, according to which form of inheritance has 
prevailed. Inheritance is governed by so many un- 



410 SEXUAL SELECTION. Part II. 

known laws or conditions, that they seem to us to be 
most capricious in their action ; 23 and we can so far 
understand how it is that with closely-allied species the 
sexes of some differ to an astonishing degree, whilst 
the sexes of others are identical in colour. As the 
successive steps in the process of variation are neces- 
sarily all transmitted through the female, a greater 
or less number of such steps might readily become 
developed in her; and thus we can understand the 
frequent gradations from an extreme difference to no 
difference at all between the sexes of the species within 
the same group. These cases of gradation are much 
too common to favour 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. With respect to the differences between the 
females of the species in the same genus or family, we 
can perceive that they depend, at least in part, on the 
females partaking of the colours of their respective 
males. This is well illustrated in those groups in which 
the males are ornamented to an extraordinary degree ; 
for the females in these groups generally partake to a 
certain extent of the splendour of their male partners. 
Lastly, we continually find, as already remarked, that 
the females of almost all the species in the same genus, 
or even family, resemble each other much more closely 
in colour than do the males ; and this indicates that 
the males have undergone a greater amount of modifi- 
cation than the females. 



23 < The Variation of Animals and Plants under Domestication, 
vol. ii. chap. xii. p. 17. 



Chap. XL BUTTERFLIES AND MOTHS. 411 

Mimickry. — This principle was first made clear in an 
admirable paper by Mr. Bates, 24 who tlms threw a flood 
of light on many obscure problems. It had previously 
been observed that certain butterflies in S. America 
belonging to quite distinct families, resembled the Heli- 
conidee so closely in every stripe and shade of colour 
that they could not be distinguished except by an 
experienced entomologist. As the HeliconidaB are 
coloured in their usual manner, whilst the others depart 
from the usual colouring of the groups to which they 
belong, it is clear that the latter are the imitators, and 
the Heliconidse the imitated. Mr. Bates further observed 
that the imitating species are comparatively rare, whilst 
the imitated swarm in large numbers ; the two sets 
living mingled together. From the fact of the Heli- 
conidae being conspicuous and beautiful insects, yet 
so numerous in individuals and species, he concluded 
that they must be protected from the attacks of birds 
by some secretion or odour ; and this hypothesis has 
now been confirmed by a considerable body of curious 
evidence. 25 From these considerations Mr. Bates in- 
ferred that the butterflies which imitate the protected 
species had acquired their present marvellously decep- 
tive appearance, through variation and natural selection, 
in order to be mistaken for the protected kinds and 
thus to escape being devoured. No explanation is 
here attempted of the brilliant colours of the imi- 
tated, but only of the imitating butterflies. We must 
account for the colours 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 



24 ' Transact. Linn. Soc.' vol. xxiii. 1862, p. 495. 

25 ' Proc. Ent. Soc' Dec. 3rd, I860, p. xlv. 



412 SEXUAL SELECTION. Part II. 

by Mr. Wallace 26 in the Malayan region, and by 
Mr. Trimen in South Africa. 

As some writers 27 have felt much difficulty in under- 
standing how the first steps in the process of mimickry 
could have been effected through natural selection, it 
may be well to remark that the process probably has 
never commenced with forms widely dissimilar in colour. 
But with two species moderately like each other, the 
closest resemblance if beneficial to either form could 
readily be thus gained ; and if the imitated form was 
subsequently and gradually modified through sexual 
selection or any other means, the imitating form would 
be led along the same track, and thus be modified to 
almost any extent, so that it might ultimately assume 
an appearance or colouring wholly unlike that of the 
other members of the group to which it belonged. As 
extremely slight variations in colour would not in many 
cases suffice to render a species so like another pro- 
tected species as to lead to its preservation, it should 
be remembered that many species of Lepidoptera are 
liable to considerable and abrupt variations in colour. 
A few instances have been given in this chapter ; but 
under this point of view Mr. Bates' original paper on 
mimickry, as well as Mr. Wallace's papers, should be 
consulted. 

In the foregoing cases both sexes of the imitating 
species resemble the imitated ; but occasionally the 



26 ' Transact. Linn. Soc' vol. xxv. 1865, p. 1 ; also ' Transact. Ent. 
Soc' vol. iv. (3rd series), 1867, p. 301. 

2 ' See an ingenious article entitled, " Difficulties of the Theory of 
Natural Selection," in the ' Month,' 1869. The writer strangely sup- 
poses that I attribute the variations in colour of the Lepidoptera, by 
which certain species belonging to distinct families have come to 
resemble others, to reversion to a common progenitor ; but there is no 
more reason to attribute these variations to reversion than in the case 
of any ordinary variation. 



Chap. XI. BUTTERFLIES AND MOTHS. 41 



o 



female alone mocks a brilliantly-coloured and protected 
species inhabiting the same district. Consequently the 
female differs in colour from her own male, and, which 
is a rare and anomalous circumstance, is the more 
brightly-coloured of the two. In all the few species of 
Pieridae, in which the female is more conspicuously 
coloured than the male, she imitates, as I am informed 
by Mr. Wallace, some protected species inhabiting the 
same region. The female of Diadema anomala is rich 
purple-brown with almost the whole surface glossed with 
satiny blue, and she closely imitates the Eujoloea mida- 
mus, "one of the commonest butterflies of the East;" 
whilst the male is bronzy or olive-brown, with only a 
slight blue gloss on the outer parts of the wings. 28 
Both sexes of this Diadema and of D. bolina follow 
the same habits of life, so that the differences in colour 
between the sexes cannot be accounted for by exposure 
to different conditions; 29 even if this explanation were 
admissible in other instances. 30 

The above cases of female butterflies which are more 
brightly-coloured than the males, shew us, firstly, that 
variations have arisen in a state of nature in the female 
sex, and have been transmitted exclusively, or almost ex- 
clusively, to the same sex ; and, secondly, that this form 
of inheritance has not been determined through natural 
selection. For if we assume that the females, before 
they became brightly coloured in imitation of some pro- 
tected kind, were exposed during each season for a longer 
period to danger than the males ; or if we assume that 



28 Wallace, "Notes on Eastern Butterflies," 'Transact. Ent. Soc.' 
1869, p. 287. 

29 Wallace, in 'Westminster Eeview,' July, 1867, p. 37; and in 
' Journal of Travel and Nat. Hist.' vol. i. 1868, p. 88. 

30 See remarks by Messrs. Bates and Wallace, in ' Proc. Ent. Soc.' 
Nov. 19, 1866, p. xxxix. 



414 SEXUAL SELECTION. Part II. 

they could not escape so swiftly from their enemies, 
we can understand how they alone might originally 
have acquired through natural selection and sexually- 
limited inheritance their present protective colours. 
But except on the principle of these variations having 
been transmitted exclusively to the female offspring, 
we cannot understand why the males should have re- 
mained dull-coloured ; for it would surely not have 
been in any way injurious to each individual male to 
have partaken by inheritance of the protective colours 
of the female, and thus to have had a better chance 
of escaping destruction. In a group in which brilliant 
colours are so common as with butterflies, it cannot be 
supposed that the males have been kept dull-coloured 
through sexual selection by the females rejecting the 
individuals which w r ere rendered as beautiful as them- 
selves. We may, therefore, conclude that in these cases 
inheritance bv one sex is not due to the modification 
through natural selection of a tendency to equal inherit- 
ance by both sexes. 

It may be well here to give an analogous case in 
another Order, of characters acquired only by the female, 
though not in the least injurious, as far as we can judge, 
to the male. Amongst the Phasinicke, or spectre-insects, 
Mr. Wallace states that " it is often the females alone 
" that so strikingly resemble leaves, while the males show 
" only a rude approximation." Now, whatever may be 
the habits of these insects, it is highly improbable that 
it could be disadvantageous to the males to escape de- 
tection by resembling leaves. 31 Hence we may conclude 



31 See Mr. Wallace in 'Westminster Keview,' July, 1867, p. 11 and 
37. The male of no butterfly, as Mr. Wallace informs me, is known to 
differ in colour, as a protection, from the female ; and he asks me how 
I can explain this fact on the principle that one sex alone has varied 
and has transmitted its variations exclusively to the same sex, without 



Chap. XL BUTTERFLIES AND MOTHS. 415 

that the females alone in this latter as in the previous 
cases originally varied in certain characters ; these cha- 
racters having been preserved and augmented through 
ordinary selection for the sake of protection and from 
the first transmitted to the female offspring alone. 

Bright Colours of Caterpillars. — Whilst reflecting on 
the beauty of many butterflies, it occurred to me that 
some caterpillars were splendidly coloured, 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 colours of their 
larvae could be in some manner explained. In the first 
place it may be observed that the colours of caterpillars 
do not stand in any close correlation with those of the 
mature insect. Secondly, their bright colours do not 



the aid of selection to check the variations being inherited by the 
other sex. No doubt if it could be shewn that the females of very 
many species had been rendered beautiful through protective miinickry, 
but that this has never occurred with the males, it would be a serious 
difficulty. But the number of cases as yet known hardly suffices for a 
fair judgment. We can see that the males, from having the power of 
flying more swiftly, and thus escaping danger, would not be so likely 
as the females to have had their colours modified for the sake of protec- 
tion ; but this would not in the least have interfered with their receiving 
protective colours through inheritance from the females. In the second 
place, it is probable that sexual selection would actually tend to prevent 
a beautiful male from becoming obscure, for the less brilliant individuals 
would be less attractive to the females. Supposing that the beauty of 
the male of any species had been mainly acquired through sexual 
selection, yet if this beauty likewise served as a protection, the acquisi- 
tion would have been aided by natural selection. But it would be 
quite beyond our power to distinguish between the two processes of 
sexual and ordinary selection. Hence it is not likely that we should 
be able to adduce cases of the males having been rendered brilliant 
exclusively through protective mimickry, though this is comparatively 
easy with the females, which have rarely or never been rendered beau- 
tiful, as far as we can judge, for the sake of sexual attraction, although 
they have often received beauty through inheritance from their male 
parents. 



416 SEXUAL SELECTION. Part II. 

serve in any ordinary manner as a protection. As an 
instance of this, Mr. Bates informs me that the most 
conspicuous 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 man who passed by at the 
distance of many yards, and no doubt of every passing 
bird. 

I then applied to Mr. Wallace, who has an innate 
genius for solving difficulties. After some consideration 
he replied : " Most caterpillars require protection, as 
" may be inferred from some kinds being furnished 
" with spines or irritating hairs, and from many being 
" coloured green like the leaves on which they feed, 
'•' or curiously like the twigs of the trees on which they 
" live." I may add as another instance of protection, 
that there is a caterpillar of a moth, as I am informed 
by Mr. J. Mansel Weale, which lives on the mimosas in 
South Africa, and fabricates for itself a case, quite un- 
distinguishable from the surrounding thorns. From 
such considerations Mr. Wallace thought it probable 
that conspicuously-coloured caterpillars were protected 
by having a nauseous taste ; but as their skin is ex- 
tremely tender, 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 insufficient to protect a caterpillar unless 
" some outward sign indicated to its would-be destroyer 
" that its prey was a disgusting morsel." Under these 
circumstances it would be highly advantageous to a 
caterpillar to be instantaneously and certainly recog- 
nised as unpalatable by all birds and other animals. 



Chap. XI. SUMMAEY ON INSECTS. 417 

Thus the most gaudy colours would be serviceable, and 
might have been gained by variation and the survival 
of the most easily-recognised individuals. 

This hypothesis appears at first sight very bold ; but 
when it was brought before the Entomological Society 32 
it was supported by various statements ; and Mr. J. 
Jenner Weir, who keeps a large number of birds in an 
aviary, has made, as he informs me, numerous trials, 
and finds no exception to the rule, that all caterpillars 
of nocturnal and retiring habits with smooth skins, 
all of a green colour, and all which imitate twigs, are 
greedily devoured by his birds. The hairy and spinose 
kinds are invariably rejected, as were four conspicuously- 
coloured species. When the birds rejected a caterpillar, 
they plainly shewed, by shaking their heads and cleans 
ing their beaks, that they were disgusted by the taste. 
Three conspicuous kinds of caterpillars and moths were 
also given by Mr. A. Butler to some lizards and frogs, 
and were rejected ; though other kinds were eagerly 
eaten. Thus the probable truth of Mr. Wallace's view 
is confirmed, namely, that certain caterpillars have been 
made conspicuous for their own good, so as to be easily 
recognise 1 by their enemies, on nearly the same prin- 
Ciple that certain poisons are coloured by druggists for 
the good of man. This view will, it is probable, be 
hereafter extended to many animals, which are coloured 
in a conspicuous manner. 

Summary and Concluding Remarks on Insects. — 
Looking back to the several Orders; we have seen that 
the sexes often differ in various characters, the meaning 



33 



32 « Proc. Eutomolog. Soc' Dec. 3rd, 1866, p. xlv., and March 4th, 

1867, p. Ixxs. 

33 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. 

VOL. I. ^ E 



418 SEXUAL SELECTION. Part II. 

of which is not understood. The sexes, also, often differ 
in their organs of sense or locomotion, so that the males 
may quickly discover or reach the females, and still 
oftener in the males possessing diversified contrivances 
for retaining the females when found. But we are not 
here much concerned 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 probably it is that the 
males have not often been rendered larger and stronger 
than the females. On the contrary they are usually 
smaller, in order that they may be developed within a 
shorter time, so as to be ready in large numbers for the 
emergence of the females. 

In two families of the Homoptera the males alone 
possess, in an efficient state, organs which may be called 
vocal ; and in three families of the Orthoptera the males 
alone possess stridulating organs. In both cases these 
organs are incessantly used during the breeding-season, 
not only for calling the females, but for charming or 
exciting them in rivalry with other males. No one 
who admits the agency of natural selection, will dispute 
that these musical instruments 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. Even 
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 



Chap. XI. SUMMAKY ON INSECTS: 419 

through sexual selection. It is instrutive to reflect 
on the wonderful diversity of the means for producing 
sound, possessed by the males aloue or by both sexes 
in no less than six Orders, and which were possessed 
by at least one insect at an extremely remote geolo- 
gical epoch. We thus learn how effectual sexual selec- 
tion has been in leading to modifications of structure, 
which sometimes, as with the Homoptera, are of an im- 
portant nature. 

From the reasons assigned in the last chapter, it is 
probable that the great horns of the males of many 
lamellicorn, and some other beetles, have been ac- 
quired as ornaments. So perhaps it may be with cer- 
tain other peculiarities confined to the male sex. From 
the small size of insects, we are apt to undervalue their 
appearance. If we could imagine a male Chalcosoma 
(fig. 15) with its polished, bronzed coat of mail, and 
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 colouring of insects is a complex and obscure 
subject. When the male differs slightly from the female, 
and neither are brilliantly coloured, it is probable that 
the two sexes have varied in a slightly different manner, 
with the variations transmitted to the same sex, without 
any benefit having been thus derived or evil suffered. 
When the male is brilliantly coloured and differs con- 
spicuously from the female, as with some dragon-flies 
and many butterflies, it is probable that he alone has 
been modified, and that he owes his colours to sexual 
selection ; whilst the female has retained a primordial 
or very ancient type of colouring, slightly modified by 
the agencies before explained, and has therefore not 
been rendered obscure, at least in most cases, for the 
sake of protection. But the female alone has soine- 

2 e 2 



420 SEXUAL SELECTION. Fart II. 

times been coloured brilliantly so as to imitate other 
protected species inhabiting the same district. When 
the sexes resemble each other and both are obscurely 
coloured, there is no doubt that they have been in a 
multitude of cases coloured for the sake of protection. 
So it is in some instances when both are brightly 
coloured, causing them to resemble surrounding objects 
such as flowers, or other protected species, or indirectly 
by giving notice to their enemies that they are of an 
unpalatable nature. In many other cases in which the 
sexes resemble each other and are brilliantly coloured, 
especially when the colours are arranged for display, we 
may conclude that they have been gained by the male 
sex as an attraction, and have been transferred to both 
sexes. We are more especially led to this conclusion 
whenever the same type of coloration prevails through- 
out a group, and we find that the males of some species 
differ widely in colour from the females, whilst both 
sexes of other species are quite alike, with intermediate 
gradations connecting these extreme states. 

In the same manner as bright colours 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 
vocal or instrumental organs proper to the males of 
the Homoptera and Orthoptera have generally been 
transferred in a rudimentary, or even in a nearly perfect 
condition to the females ; yet not sufficiently perfect to 
be used for producing sound. It is also an interesting 
fact, as bearing on sexual selection, that the stridulating 
organs of certain male Orthoptera are not fully deve- 
loped until the last moult ; and that the colours of cer- 
tain 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. 



Chap. XI. SUMMAEY ON INSECTS. 421 

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 rare exceptions, is the most ornamented and 
departs most 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 habit- 
ually or occasionally prefer the more beautiful males, 
and that these have thus acquired their beauty. That 
in most or all the orders the females have the power 
of rejecting any particular male, we may safely infer 
from the many singular contrivances possessed by the 
males, such as great jaws, adhesive cushions, spines, 
elongated legs, &c, for seizing the female ; for these 
contrivances shew that there is some difficulty in the 
act. In the case of unions between distinct species, 
of which many instances have been recorded, the 
female must have been a consenting party. Judging 
from what we know of the perceptive powers and 
affections of various insects, there is no antecedent im- 
probability in sexual selection having come largely into 
action ; but we have as yet no direct evidence on this 
head, and some facts are opposed to the belief. Never- 
theless, 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 colours or other 
ornaments, with which the male alone is decorated. 

If we admit that the females of the Homoptera and 
Orthoptera appreciate the musical tones emitted by their 
male partners, and that the various instruments for this 
purpose have been perfected through sexual selection, 
there is little improbability in the females of other 
insects appreciating beauty in form or colour, and con- 
sequently in such characters having been thus gained 



422 SEXUAL SELECTION. Part II. 

by the males. But from the circumstance of colour 
being so variable, and from its having been so often 
modified for the sake of protection, it is extremely 
difficult to decide in how large a proportion of cases 
sexual selection has come into play. This is more 
especially difficult in those Orders, such as the Orthop- 
tera, Hymenoptera, and Coleoptera, in which the two 
sexes rarely differ much in colour ; for we are thus cut 
off from our best evidence of some relation between the 
reproduction of the species and colour. 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 probable 
that all these characters have been gained through 
the same means, namely sexual selection. 

When we treat of Birds, we shall see that they pre- 
sent in their secondary sexual characters the closest 
analogy with insects. 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 colours, all evidentlv for the sake of dis- 
play. 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-coloured and unornamented. Lastly, in some few 



Chap. XI. 



SUMMARY ON INSECTS. 



423 



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. In the latter case we 
shall see that the females, like female insects, often 
possess more or less plain traces of the characters which 
properly belong to the males. The analogy, indeed, in 
all these respects between birds and insects, is curiously 
close. Whatever explanation applies to the one class 
probably applies to the other ; and this explanation, as 
we shall hereafter attempt to shew, is almost certainly 
sexual selection. 



END OF VOL. I. 



&\C4 




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Earliest Times to the Roman Conquest. With Chapters on the 
History of Literature and Art. By DR. WM. SMITH. With Woodcuts. 

THE STUDENTS ANCIENT HISTORY OF THE EAST. 

From the Earliest Times to the Conquests of Alexander the Great, including 
Egypt, Assyria, Babylonia, Media, Persia, Asia Minor, and Phoenicia. By 
PHILIP SMITH, B.A. With Woodcuts. 

THE STUDENT'S OLD TESTAMENT HISTORY. From the 

Creation to the Return of the Jews from Captivity. With Maps and 
Woodcuts. 

THE STUDENT'S NEW TESTAMENT HISTORY. With an 

Introdui tion, containing the connection of the Old and New Testaments. 
With Maps and Woodcuts. 

THE STUDENT'S MANUAL OF THE ENGLISH LAN- 
GUAGE. By GEORGE P. MARSH. Edited, with additional Chapters and 

Notes. 



12 LIST OF POPULAR WORKS. 



THE STUDENT'S MANUAL OF ENGLISH LITERATURE. 

By T. B. SHAW, M.A. Edited, with Notes and Illustrations. 

THE STUDENT'S SPECIMENS OF ENGLISH LITERA- 
TURE. Selected from the Best Writers. By THOS. B. SHAW, M.A. 
Edited, with Additions. 

THE STUDENT'S MANUAL OF ANCIENT GEOGRAPHY. 

By REV. W. L. BE VAN. With Woodcuts. 

THE STUDENT'S MANUAL OF MODERN GEOGRAPHY. 

Mathematical, Physical, and Descriptive. By REV. W. L. BEVAN. With 
Woodcuts. 

THE STUDENTS MANUAL OF MORAL PHILOSOPHY. 

With Quotations and References. By WILLIAM FLEMING, D.D. 

THE STUDENT'S BLACKSTONE. A Systematic Abridgment 

OF THE entire Commentaries. By R. MALCOLM KERR, LL.D. 

A PRACTICAL HEBREW GRAMMAR. With the Hebrew 

text of Genesis i.-vi. and Psalms i.-vi., Grammatical Analysis aud Vocabulary 
By REV. STANLEY LEATHES. 



Nine Shillings. 

THE CONNECTION OF THE PHYSICAL SCIENCES. By 

MARY SOMERVILLE. With Woodcuts. 

PHYSICAL GEOGRAPHY. By MARY SOMERVILLE. 

Revised by H. W. Bates. With Portrait. 

THE STUDENT'S ELEMENTS OF GEOLOGY. By SIR 

CHARLES LYELL. With 600 Woodcuts. 

A MANUAL OF SCIENTIFIC INQUIRY. By Various Writers. 
Edited by SIR J. F. HERSCHEL and REV. ROBERT MAIN. 

POETICAL WORKS OF LORD BYRON. With Notes, Illus- 

tratiuns, and Portrait. 

LIFE OF LORD BYRON ; with his Letters and Journals. By 
THOMAS MOORE. With Portraits. 

ARCHBISHOP BECKET; A BIOGRAPHY. By CANON 

ROBERTSON, M.A. With Illustrations. 

PICTURES OF THE CHINESE, DRAWN BY THEMSELVES. 

Described by REV. R. H. COBBOLD. With 34 Illustrations. 

THE ENGLISH BATTLES AND SIEGES OF THE PENIN- 
SULAR WAR. By SIR WILLIAM NAPIER. With Portrait. 

THE YOUNG OFFICER'S COMPANION; or, Essays on 

Military Duties and (Qualities : with Illustrations from History. By 
LORD DE ROS. 

DOG-BREAKING; the most Expeditious, Certain, and Easy 
Method, whether great Excellence or only Mediocrity be required. With 
a Few Hints for those who Love the Dog and the Gun. By GENERAL 
HUTCHINSON. With Woodcuts. 



LIST OF SCHOOL CLASSICS. 13 



By DR. WILLIAM SMITH. 
PKINCIPIA LATINA, Part I. A Fikst Latin Course. A 

Grammar, Delectus, and Exercise Book with Vocabularies. 13th Edition. 
3s. 6d. 

%* This Edition contains the Accidence arranged for the ' Public School Latin 
Primer.' 

PRINCIPIA LATINA, Part II. Latin Eeading Book. An 

Introduction to Ancient Mythology, Geography, Roman Antiquities, and 
History. With Notes and a Dictionary. 3s. 6d. 

PRINCIPIA LATINA, Part III. Latin Poetry. 1. Easy 

Hexameters and Pentameters. 2. Eclogaj Ovidianaj. 3. Prosody and Metre. 
4. First Latin Verse Book. 3s. 6d. 

PRINCIPIA LATINA, Part IV. Latin Prose Composition. 

Rules of Syntax, with Examples, Explanations of Synonyms, and Exercises 
on the Syntax. 3s. 6d. 

PRINCIPIA LATINA, Part V. Short Tales and Anecdotes 
from Ancient History, for Translation into Latin Prose. 3s. 

A LATIN-ENGLISH VOCABULARY, with a Latin-English 
Dictionary to Phaedrus, Cornelius Nepos, and Caesar's 'Gallic War.' 3s. 6d. 

THE STUDENTS LATIN GRAMMAR. By WM. SMITH, 

D.C.L., and THE0PH1LUS D. HALL. 6s. 

A SMALLER LATIN GRAMMAR. Abridged from the above 
Work. 3s. Qd. 

INITIA GR.ECA, Part I. A First Greek Course, containing 
Grammar, Delectus, Exercise Book, and Vocabularies. By DR. WM. SMITH. 
3s. 6(i. 

INITIA GR^ECA, Part II. A Reading Book ; containing short 
Tales, Anecdotes, Fables, Mythology, and Grecian History. With a Lexicon. 
3s. 6d. 

INITIA GRiECA, Part III. Greek Prose Composition; con- 
taining the Rules of Syntax, with copious Examples and Exercises. 3s. 6d. 

THE STUDENT'S GREEK GRAMMAR. By PROFESSOR 

CUR ITUS, and WM. SMITH, D.C.L. 6s. 

A SMALLER GREEK GRAMMAR. Abridged from the above 

Work. 3s. 6cZ. 



PRINCIPIA GR^ECA. A First Greek Course. A Grammar, 

Delectus, and Exercise Book, with Vocabularies. By H. E. HUTTON, M.A 
3s. 6d. 

MATTHIAS GREEK GRAMMAR. Abridged by BLOM- 
F1ELD. Revised and enlarged, by E. S. Crooke, B.A. 4s. 

KING EDWARD VI.'S FIRST LATIN BOOK; including 
a Short Syntax and Prosody with an English Translation. 2s. 6d. 

KING EDWARD VI.'S LATIN GRAMMAR. 3s. 6d. 

ENGLISH NOTES FOR LATIN ELEGIACS; designed for 
Early Proficients in the Art of Latjn Versification. By REV. W. OXENHAM. 
3s. 6d. 



14 LIST OF HANDBOOKS FOR TRAVELLERS. 



THE CONTINENT, &c. 
HANDBOOK— TRAVEL TALK, — English, French, German, 

and Italian. 3s. 6d. 

HANDBOOK — NORTH GERMANY, Holland, Belgium, 

Prussia, and the Rhine to Switzerland. With Map and Plans. 

HANDBOOK — SOUTH GERMANY, The Tyrol, Bavaria, 
Austria, Salzburg, Sttria, Hungary, and The Danube, from Ulm to the 
Black Sea. With Map and Plans. 10s. 

HANDBOOK — SWITZERLAND, The Alps of Savoy and 

Piedmont. With Maps and Plans. 10s. 

HANDBOOK — FRANCE, Normandy, Brittany, The French 
Alps, Dauphlne, Provence, and the Pyrenees, With Maps. 12s. 

HANDBOOK— PARIS AND ITS ENVIRONS. With Map and 

Plans. 3s. 6d. 

*** Murray's Plan of Paris. 3s. 6d. 
HANDBOOK — CORSICA AND SARDINIA. With Map. 4s. 
HANDBOOK — SPAIN, Madrid, The Castile.?, The Basque 

Provinces, Leon, The Asturias, Galicia, Estremadura, Andalusia, 
Ronda, Granada, Murcia, Valencia, Catalonia, Aragon, Navarre, 
The Balearic Islands, &c, &c. With Maps. 2 vols. 24s. 

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&c. With Map. 9s. 

HANDBOOK — NORTH ITALY, Piedmont, Nice, Lombardy, 

Venice, Parma, Modena, and Romagna. With Map and Plans. 12s. 

HANDBOOK — CENTRAL ITALY, Tuscany, Florence, Lucca, 
Umbria, The Marches, and the Patrimony of St. Peter. With Map. 
10s. 

HANDBOOK — ROME AND ITS ENVIRONS. With Map and 

Plans. 9s. 

HANDBOOK — SOUTH ITALY, Two Sicilies, Naples, Pompeh, 

Herculaneum, Vesuvius, Abruzzi, &c. With Map. 10s. 

HANDBOOK — SICILY, Palermo, Messina, Catania, Syracuse, 
Etna, and the Ruins of the Greek Temples. With Map. 12s. 

HANDBOOK — E G Y P T, The Nile, Alexandria, Cairo, 
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HANDBOOK — GREECE, The Ionian Islands, Athens, 
Albania , Thessaly, and Macedonia. With Map. 

HANDBOOK — Constantinople, The Bosphoris, Dardanelles, 

Brousa, and Plain of Troy, with General Hints for Travellers in Turkey, 
&c. With Map 



LIST OF HANDBOOKS FOR TRAVELLERS. 15 



HANDBOOK — DENMABK, Norway, Sweden, and Iceland. 

With Map and Plans. 

HANDBOOK — KUSSIA, St. Petersburg, Moscow, Finland, &c. 

With Map. 15s. 

HANDBOOK— INDIA, Bombay and Madras. With Map. 2 vols. 

12s. each. 

HANDBOOK — HOLY LAND, Syria, Palestine, Sinai, Edom, 

and the Syrian Deserts. With Map. 2 vols. 24s. 



KNAPSACK GUIDES FOR TRAVELLERS. 
KNAPSACK GUIDE TO SWITZEKLAND. With Plans. 5s. 
KNAPSACK GUIDE TO NOEWAY. With Map. 6s. 
KNAPSACK GUIDE TO ITALY. With Plans. 6s. 
KNAPSACK GUIDE TO THE TYROL. With Plans. 6s. 



ENGLAND AND WALES. 



HANDBOOK — LONDON AS IT IS. With Map and Plans. 

3S. 6d. 

HANDBOOK — ESSEX, CAMBEIDGE, SUFFOLK, AND 
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Yarmouth, Cromer, &c. With Maps and Plans. 12s. 

HANDBOOK — KENT AND SUSSEX — Canterbury, Dover, 
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tings, Lewes, Arundel. With Map. lus. 

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mouth, and The Isle of Wight. With Map. IDs. 

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Map. 7a. 6d. 

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Taunton, &c. With Map. 10s. 

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Ilfracombe, Linton, Sidmouth, Dawlish, Teignmouth, Plymouth, Devon- 
port, Torquay, Launceston, Penzance, Falmouth, The Lizard, Land's 
End, &c. With Map. 10s. 



16 LIST OF HANDBOOKS FOR TRAVELLERS. 



HANDBOOK — GLOUCESTER, HEREFORD, AND 

WORCESTER — Cirencester, Cheltenham, Stroud, Tewkesbury, Leo- 
minster, Ross, Malvern, Kidderminster, Dudley, Bromsgrove, Evesham. 
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HANDBOOK — SOUTH WALES — Monmouth, Carmarthen, 

Tenby, Swansea, and the Wye, &c. With Map. 7s. 

HANDBOOK — DERBY, NOTTS, LEICESTER, AN^» 

STAFFORD — Matlock, Bakewell, Chatsworth, The Peak, Bu> 
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Walsall, Tamworth. With Map. 7s. 6d. 

HANDBOOK — SHROPSHIRE, CHESHIRE, AND LANCA- 
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Bradford, Halifax, Huddersfield, Sheffield. With Map. 12s. 

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Lancaster, Furness Abbey, Ambleside, Kendal, Windermere, Coniston, 
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*** Murray's Map op the Lake District, 3s. 6d. 

HANDBOOK — SCOTLAND — Edinburgh, Melrose, Kelso, 
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HANDBOOK — IRELAND— Dublin, Belfast, Donegal, Gal- 
way, Wexford, Cork, Limerick, Waterford, Killarney, Munster. 
With Map. 12s. 



JOHN MURRAY, 50a, ALBEMARLE STREET. 



LONDON: PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET, 

AND CHARING CROSS. 



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